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The Academic Edge Press delegates to organising the first workshop on Research Paper Writing for 2025.
This workshop provides a clear and practical guide to writing research papers, aimed at students, early-career researchers, and professionals. Participants will learn how to develop a strong research question, conduct a focused literature review, structure their paper effectively, and meet academic writing standards. The session also covers common writing challenges, tips for clarity and coherence, and strategies for successful submission to journals or conferences.
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That's a great workshop. I'm hoping for the best.
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I have a Coherent Mira 900 femtosecond mode-locked laser with a repetition rate of 76 MHz. I am interested in modifying the repetition rate to 80 MHz by shortening the cavity length by approximately 9.87 cm. I am wondering if anyone has experience modifying a Mira laser in this way and could kindly share their insights or advice.
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Do you have any specific question to that laser? I havent worked with that particular model. But usually you unmount one of mirrors and mount to to a position of 9-10 cm shorter, as you calculated. Usually the manual should tell you which mirror to move. Then you align the laser again following the instructions by the manual.
Usually, the manual should supply you with alignment instructions and steps also for shortening the cavity.
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What if I told you that wavefunction collapse is a recursive thermodynamic event rather than being invoked by an observer? The system undergoes collapse when energy and structural coherence achieve self-reference. Observation is not an external intervention—it is the onset of recursive self-persistence. What collapses the wavefunction is not the eye of an outsider, but the recursive eye that folds back into the system itself.
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My framing doesn’t depend on the wavefunction being real per se, but rather proposes that what we call “collapse” emerges when recursive thermodynamic coherence within the system reaches self-persistence—essentially when the system begins to reference itself. It’s not that measurement "forces" a collapse, but that what we interpret as measurement is the manifestation of a deeper recursive threshold being crossed. I see this not as replacing standard QM tools, but as offering a thermodynamic interpretation of when and why those tools snap into definite outcomes.
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I’m exploring whether consciousness can be experimentally modulated or disrupted through targeted interference with protein-level fluctuations or thermo-qubit dynamics, specifically under conditions of entropic loading and scale-dependent energy flow.
Theoretical models (e.g., Dynamic Organicity Theory, ODTBT) suggest that brain states emerge from multiscale thermodynamic processes, where fluctuations in molecular structures (like membrane proteins) help shape oscillatory coherence across neural networks.
From this view, consciousness is not static, but dynamically tied to oscillatory phase coherence, and potentially elevated through negentropic processes. This implies that entropic scaling (e.g., energy density across molecular to network scales) could influence the brain's transition into higher-frequency oscillatory states (e.g., alpha → gamma), or conversely, disrupt integration when coherence is lost.
My central questions:
  • Have there been experimental investigations into how manipulating protein conformational dynamics or quantum-thermal fluctuation regimes (thermo-qubits) affect consciousness?
  • Has anyone explored whether entropy gradients or energy scaling conditions contribute to the elevation or degradation of brainwave states?
  • Are there studies that combine molecular dynamics, thermodynamic modeling, and EEG/MEG tracking to correlate biochemical shifts with phase-state transitions in neural activity?
Any leads on empirical work, experimental setups, or cross-disciplinary studies are welcome, especially those connecting biophysical fluctuation, entropic thresholds, and neural synchronization to shifts in consciousness.
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Dear Karin,
Thank you for your detailed and helpful response, it’s exactly the kind of neurophysiological specificity I was hoping to surface. Your point about serotonin-induced activation of the claustrum and the role of the MRN/IPN in suppressing theta states is interesting.
I'm intrigued by your mention of how these structures modulate arousal-promoting nuclei like the basal forebrain, VTA, and medial septum. From the standpoint of a model I am developing, ODTBT, these circuits can be interpreted as coherence regulators operating across nested phase hierarchies. When they inhibit theta and gamma alignment, the system undergoes what the model distinguishes as Threshold Waveform Interface for State Change (TWIST), which is a recursive coherence collapse that in this case appears to be the interface for altered or unconscious states.
Your framing reinforces the idea that consciousness is not a binary state, but a transductive geometry, a structure that can be reconfigured through entropic flow and phase disruption at multiple biological scales.
If you know of any further studies that empirically map protein-level thermodynamics or phase gating structures to EEG coherence or entropy modulation, I’d be deeply interested.
Thank you again, your contribution greatly advanced the scope of my inquiry.
Warm regards,
John
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I am a PhD student in geography, working on integrating the concepts of climate change, sustainability, and geomorphology into a single research paper. I am looking for ways to integrate these concepts in a logical and coherent manner into a research paper that deals with a specific region in Jordan. I would like to ask you to help me suggest approaches and methodologies that can help me develop this topic in line with current research trends and contribute to providing solutions to environmental challenges. Any ideas or suggestions would be greatly appreciated.
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Methodologically, first the relief and its tectonic genesis. So the neotectonic processes in the Neogene and Quaternary that affected the analyzed terrain and the emergence of large morphotectonic structures. Within the morphoevolution of larger morphotectonic units, smaller-more recent landforms are distinguished, primarily created by exo-geomorphological processes caused by climatic influence and climate changes. So after morphotectonics, the sequence of analyses of climate changes and the development (morphoevolution) of genetic types of relief - aeolian, fluvial, slope, etc. Only at the end of the work, within the framework of man's modern influence on the climate and geomorphological processes, will spatial planning - scientific guidelines for sustainability in the analyzed-researched area be given.
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According to the International Code of Nomenclature for algae, fungi, and plants (ICN), a type must be a preserved physical specimen. The current rules do not recognize a DNA sequence alone as a valid type.
Do you think in fungal/plant taxonomy naming species solely based on DNA could lead to an excessive splitting of taxa and loss of taxonomic coherence?
I wish to hear your opinion and insight on this topic.
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This has been proposed and discussed: see
(093–096) Proposals to permit nuclear DNA sequences as nomenclatural types when preservation of specimens is not feasible Susanne S. Renner Washington University, Department of Biology, Saint Louis, Missouri 63130, U.S.A. Address for correspondence: Susanne S. Renner, srenner@wustl.edu DOI https://doi.org/10.1002/tax.12607
and respective decissions....however, over time things might change - evolve!
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Observing repeatable banding in xray images, unable to trace the source.
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X-rays exhibit all the properties inherent of light, but in such a different degree as to modify greatly their practical behavior
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# 163
Dear Sarbast Moslem , Baris Tekin Tezel, Ayse Ovgu Kinay, Francesco Pilla
I read your paper:
A hybrid approach based on magnitude-based fuzzy analytic hierarchy process for estimating sustainable urban transport solutions
My comments:
1- In the abstract you say “The study employs the newly developed Magnitude Based Fuzzy Analytic Hierarchy Process, chosen for its accuracy and computational efficiency compared to existing methods”
Are you aware that Saaty explained that it is incorrect to apply fuzzy in AHP because it is already fuzzy?
Since when using intuition ensures accuracy? Do you have any proof of what you say?
Sensitivity analysis does not ensure quality, what it does us to find how strong is a solution
2- In page 2 you talk about linear regression for evaluation. Linear regression is used to predict the value of a dependent variable on the value of one or more independent variables.
3- In page 3 “AHP offers mechanisms for ensuring consistency in decision-making through pairwise comparisons and sensitivity analyses”
True, AHP ensures consistency by FORCING to adhere to transitivity, by imposing the DM to change his/her estimates.What it ensures, is transitivity without any mathematical foundation,just for the sake of the method. Therefore, this ‘consistency’ is fabricated.
Even if there is a real consistency, it reflects the coherence of the DM, but it does not necessarily mean that consistency and weights can be applied to the real-world. There is no mathematical support for this assumption, neither to assume that the world is consistent, let alone common sense; it is convenient indeed, for the method, but useless for evaluation
4- Page 3 “On the other hand, expressing the data in the form of fuzzy numbers to better express the uncertainty in individual judgments has led to the suggestion and widespread use of fuzzy AHP (FAHP) methods, which include calculations based on fuzzy arithmetic”
5- In several parts of the paper it mentions validation of results. That is only a wish, because no MCDM method has any real yardstick to compare to. It is another and very common fallacy.
6- Pag 8, Fig 4. I understand of that waiting time does not depend on speed but on frequency buses arrival (Number of buses of the same route per hour). The more the frequency the lesser the waiting tine. What role do have the buses speed here? It appears that this concept does not come from transportation experts.
“Reaching to the destination without shifting buses”
I guess that interchanging buses or routes is more adequate
Need of transfer” normally refers to paying a single ticket, that allows a pax to change bus routes, that is, you he can board another bus with the same ticket
Your definition on “Time availability” does not seen too coherent, because what “Number of times that UBT is deployed??? over a route” mean?
“Limited time of use” (C4.2)????. I understand that you want to say ‘Operating hours’, that is start running and finish running, or simply ‘Scheduling’. I am afraid that your expression does not belong to the urban transportation industry.
Please do not be offended with my observations, it is not my intention. Only that is you want readers understanding what you write, you must use the appropriate words. If not, your work risks to be misunderstood and downgraded
Why “providing new buses” is related to “comfort” in stops?
7- Page 9 “In other words, it models the state of uncertainty in the mind of the decision-maker.”
Very true, but why those uncertainties of a MIND can be translated to real-life? In other words, what theorem or axiomsupports that what the DM estimates can be used in real-world? It is a simple assumption that even defies common sense. In my opinion, it does not make any sense to apply fuzzy to invented values. Yes, one will get a crisp value, and what is it good for? For nothing
These are some of my comments. Hope that they can help you
Nolberto Munier
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Sarbast Moslem added a reply
Dear Nolberto Munier , thank you so much for your constructive feedbacks ,
NM-You are most welcome, and I deeply thank and appreciate your answer
SM- Fuzzy AHP is not universally superior but offers advantages in high-uncertainty contexts, here I tried to cover most of your interesting comments,
NM – AHP is universally known, I grant it, but it does not mean that it is effective, in my opinion it is irreal and flawed. What FAHP does is simply find an average value on the DM estimates. Please, look at this from fuzzy analytic hierarchy process
Toly Chen (2020) “FAHP) has been extensively applied to multi-criteria decision making (MCDM). However, the computational burden resulting from the calculation of fuzzy eigenvalue and eigenvector is heavy. As a result, a FAHP problem is usually solved using approximation techniques such as fuzzy geometric mean (FGM) and fuzzy extent analysis (FEA) instead of exact methods. Therefore, the FAHP results are subject to considerable inaccuracy”
So, the DM accumulates inaccuracy on uncertainty. Your opinion please.
SM- 1. Saaty’s critique of Fuzzy AHP
Saaty argued that AHP inherently accounts for uncertainty through its 1–9 scale and consistency checks. However, fuzzy AHP proponents contend that fuzzy sets better model linguistic ambiguity (e.g., "somewhat important") and granular uncertainty. Empirical studies (e.g., Kahraman et al., 2003; Bozbura et al., 2007) demonstrate fuzzy AHP’s effectiveness in complex, uncertain contexts. Sensitivity analysis here tests robustness, not "accuracy," but computational efficiency can be shown via reduced pairwise comparisons or faster convergence in fuzzy logic frameworks.
NM- You are using the right words “Saaty argued” for its table and consistency checks.
I agree that fuzzy models better linguistic ambiguity, but just for the benefit of the DM, not for the project. Now I ask you? Why the measure of the DM coherence must affect the problem?
Another question, how Kahrarman and Bozhura demonstrate that fuzzy AHP is effective, if they do not have a yardstick to measure it? You do not need mathematics for this, only common sense and reasoning, which as probably you noticed, is the way I analyze a method in discussions
Regarding SA you are correct, its purpose is to measure strength of the best solution, and this is very useful indeed, but may I remind you that SA in AHP consists in selecting as most important criterion to vary, the one with the highest weight, without any mathematical proof of that, all based in intuitions? In addition, by selecting only one criterion and keeping the other constant (ceteris paribus), the DM is applying an incorrect procedure.
SM- Saaty argued that AHP inherently accounts for uncertainty through its 1–9 scale and consistency checks.”
NM- Now, why estimates from a DM must be consistent? In my opinion, it is due to the way Eigen Value (EI) can be applied. If you have an inconsistent matrix the EV delivers the weakest weight, therefore it is only a convenient feature for AHP
SM- 2. Linear Regression for Evaluation
Linear regression may evaluate relationships between variables (e.g., ridership vs. service quality). If the paper uses it to predict outcomes (e.g., demand), this aligns with standard practice. If used to assess criteria weights, clarification is needed, as AHP/FAHP is better suited for weighting.
NM- I do not follow your reasoning. Linear regression is a mathematical process while AHP is not
SM-3. Consistency in AHP
AHP enforces transitivity(if A > B and B > C, then A > C) via the consistency ratio (CR), flagging illogical judgments. While CR ensures internal coherence, it does not guarantee real-world validity. This is a limitation of any preference-based method. However, consistency checks reduce arbitrary biases, making weights more reliable for stakeholders.
NM- You used the correct word “enforcestransitivity. Do you think that is it natural that a formula disavows the estimate of a DM? At least you recognize that it does not guaranty real-world validity, something that Saaty also said, and I do not think that there is MCDM method that models reality in its integrity, but rational methods like POMETHEE ELECTRE, TOPSIS, VIKOR, use reasoning, analysis, experience, research, consultation, something that AHP ignores
SM- 4. Fuzzy Numbers in FAHP
Fuzzy numbers explicitly model uncertainty (e.g., "between moderate and strong preference"). While defuzzification produces crisp outputs, the process preserves uncertainty ranges, offering richer insights than deterministic AHP.
NM- Fuzzy logic only finds the average of the DM estimates. And where the uncertainty ranges come from?
Do you know that there are rational MCDM methods that can determine them, and in published papers with real-life examples?
SM- 5. Validation in MCDM
Validation in MCDM often relies on expert consensus, sensitivity analysis, or benchmarking against historical decisions. While no universal "yardstick" exists, practical applicability and stakeholder acceptance validate results.
NM- Consensus is not validation. The first implies an agreement of intervening parties, each one yielding on some issue and taken on another. Validation is to compare a ranking from analytical tools with the true, existing ranking, that is completely unknown and not available to any MCDM method. Therefore, validation is impossible. Just think that if the DM knew the true results, applying MCDM would be unnecessary
Validation is not related to sensitivity analysis (SA), that tries to determine the strength of the best alternative when criteria, not a criterion, in most cases, is increased/decreased. If the best alternative depends on say three criteria, and for reach one there is a reasonable allowed variation gap, the DM can decide that said alternative is strong, but this is not validation
SM- 6. Transportation Terminology
· Waiting Time: Corrected—waiting time depends on frequency, not speed. Speed affects in-vehicle travel time
NM- Agreed. I think that I made a mistake, sorry for this. Waiting time also depends on other aspects as capacity, benches, information screen, punctuality of buses, weather (temperature, In some Canadian cities heaters are installed, while in Dubai air conditioning is a must. Therefore, it is not as simple
· Transfer Need: Revised to "interchanging buses/routes."
· Time Availability: Clarified as "service frequency" (buses/hour).
· Limited Time of Use: Adjusted to "operating hours" (e.g., 6 AM–10 PM).
· Comfort in Stops: "Providing new buses" may improve seating/shelters at stops, indirectly enhancing comfort.
NM- Providing new more comfortable buses is comfort on board. Seating in shelters provides comfort on land between buses, that must provide comfort too, such as: Easy boarding for old and people in wheelchairs, enough number of seats, screen signaling the next arrival to a station, comfortable temperature, information, cleanliness, etc.,
SM- 7. Fuzzy Logic and Real-World Relevance
Fuzzy logic is axiomatically grounded in Zadeh’s theory (1965) to model human reasoning under uncertainty. While fuzzy outputs are approximations, they reflect realistic trade-offs in ambiguous contexts (e.g., public transit preferences). The value lies in structuring qualitative judgments, not precise predictions.
NM - Agreed on fuzzy logic. Do you know that Saaty said that fuzzy should not be used in AHP because the method is already fuzzy? In my opinion, fuzzy lies on estimated geometrical forms to determine memberships, and using for instance, three invented values. Therefore, it can correctly average the DM coherence, but it is not related to reality, what is the really important.
Dear Szabolcs Duleba ,
NM-It would very productive is Mr. Duleba can collaborate in this important subject
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Themes ought to include:
guaranteeing accurate portrayal of participants' opinions.
both externally divergent (different from other themes) and internally consistent (coherence within the theme).
evaluated iteratively, incorporating triangulation or peer debriefing to increase dependability.
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If anyone has perspectives please share
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in many laser amp system,
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Short answer: no.
The coherence length defines a distance over which if you know (or control!) the phase at location A the phase at location B is no longer related to the known phase at location A. The phase at location B wanders with respect to the phase at location A and averaging over a short time B goes through all possibilities. So at any given moment the difference in phase between point A and point B is random. Well, technically the coherence length is defined at a location where the phase isn’t quite yet completely uncorrelated but it’s getting there.
So, if you hold the phase of laser X constant relative to the phase of laser Y, but then you combine them at a point where their path lengths have differed by more than a coherence length, then their phases will no longer have a fixed relation. They aren’t coherent, and you won’t get the beam quality expected of coherent beam combining.
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Could coherence thresholds in atoms offer a quantifiable link between the quantum and classical worlds, revealing an underlying pattern that governs stability across all scales of reality? If coherence scales predictably with atomic complexity, could we unlock a new framework for understanding how reality stabilizes from the quantum level to the macroscopic?
Explore the theory further in my research paper, "Scaled Coherence and Stability: A Scalable Probability Model for Atomic Structure and Quantum Field Interactions."
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Probability, prediction and assumption is not science...
Atoms are indivisible unit of our living world and all science accept this fact.. thus there is no QM
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Macro Coherence refers to the application of quantum decoherence principles to the macro realm. It suggests that multiple potential realities in the macroscopic world stabilize into a singular, observable one, similar to how wave functions collapse in quantum theory. This concept implies that, much like in quantum systems, the possibilities in the larger world 'solidify' into a single reality as coherence is lost, giving rise to the observable universe.
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I think there’s two key items:
1. Bridging Quantum and Classical Realms
Macro Coherence offers a conceptual bridge between quantum mechanics and classical physics by proposing that decoherence principles can apply beyond the microscopic. This could offer some understanding of how the “collapse” from possibilities into a singular, observed reality scales up from particles to larger objects.
Comment: If this principle holds, it could have material implications on our understanding of reality and causality in the macroscopic world. It may help explain why we perceive a consistent, singular reality despite the underlying probabilistic nature of the quantum level, providing a unifying framework for quantum and classical phenomena.
2. Role of Observer and Stability in Reality Formation
Macro Coherence suggests that, similar to quantum mechanics, the act of observation or interaction may be essential in collapsing potential states into a single macroscopic reality. This would imply that reality, as we know it, is not just a passive backdrop but something that actively stabilizes through interactions, potentially involving conscious or environmental factors.
however….
In quantum mechanics, coherence is highly sensitive to even minute environmental factors, leading to rapid decoherence for particles. In the macroscopic world, however, systems are vastly more complex and have established stability that resists decoherence-like effects, making it difficult to draw direct parallels between quantum wave function collapse and a similar “reality collapse” at a larger scale.
Without concrete evidence showing that quantum principles like decoherence can directly scale to the macroscopic level, Macro Coherence risks remaining speculative.
Furthermore, macroscopic objects consistently exhibit classical behavior without evident quantum superpositions, suggesting that decoherence might lose relevance as complexity and size increase. More empirical research would be needed to bridge this gap and validate whether quantum principles can meaningfully extend to the observable, classical reality we experience.
best
H
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Coding organizes qualitative data into themes or categories, allowing researchers to identify patterns, draw insights, and build a coherent narrative around the research questions.
Reyes, V., Bogumil, E. and Welch, L.E., 2024. The living codebook: Documenting the process of qualitative data analysis. Sociological Methods & Research, 53(1), pp.89-120.
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In qualitative data analysis (QDA), coding is a critical process used to organize and make sense of textual or non-numerical data, such as interview transcripts, observation notes, and open-ended survey responses. Coding allows researchers to systematically categorize and interpret qualitative data, drawing out themes, patterns, and insights. Here’s how coding contributes to qualitative analysis:
  1. Data Organization and Reduction: Coding helps researchers condense large amounts of qualitative data by tagging or labeling specific sections, phrases, or sentences with meaningful codes. This organizes data into manageable categories, making it easier to identify key points and reduce the complexity of the dataset.
  2. Pattern Identification: As researchers code data, patterns begin to emerge. These patterns, often in the form of recurring themes or concepts, highlight connections within the data. This is especially helpful when comparing responses across different participants or groups, making coding essential for identifying trends.
  3. Theory Development: Coding enables researchers to analyze data systematically, facilitating the development of theories or models grounded in the data itself. Through processes like open, axial, and selective coding, researchers refine categories and concepts into a structured theoretical framework.
  4. Improving Reliability: By documenting codes and their meanings, coding helps maintain consistency throughout the analysis. Using well-defined coding schemes or codebooks, particularly in studies with multiple coders, supports inter-coder reliability and reduces subjective bias in data interpretation.
  5. Facilitating Interpretation and Reporting: Coding provides a roadmap for analysis, allowing researchers to trace specific findings back to the data and provide evidence for their conclusions. Coded segments can be grouped by themes, making it easier to report findings with supporting quotes or examples from the data.
In short, coding transforms qualitative data into meaningful information that can be analyzed systematically, helping researchers build a coherent narrative and extract actionable insights.
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Key elements of a Coherent Literature Review ?
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The key elements of a coherent literature review include a clear research focus, critical analysis of existing studies, thematic organization, synthesis of findings, and identification of gaps or inconsistencies in the literature
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Currently going through impact hammer test of cantilever beam(200mmx20mmx2mm) which is made of particulate composite(Epoxy/PZT/CB). Hammer sensitivity is 2.25mV/N and accelerometer sensitivity is 100mV/g. I'm trying my best to hit the same spot without skewing to get the average value in order to find driving point. Here are some problems I've been facing.
1. Shrinking magnitude at FRF
Let's say I attached the sensor at point A and hit the opposite side. I got pretty neat 2 sharp peaks with antiresonance placed between them. When I hit the same spot again, the 2nd mode peak of FRF dropped down to 0 which become barely visible peak. Same thing happend when I hit several more time. Can I say it's because of nonlinear result due to micro cracks and voids inside the beam? (I checked many voids by SEM image)
2. Phase
If I check the degree change from 60 to -120, then is it ok to assume resonance there? And does 360 degree changing and density of phase graph doesn't have any meaning at all? Lastly, does the 180 degree phase decrement going through long range of frequency mean high damping?
3. Coherence
I know the best result of coherence is mostly at 1 with slight drops at antiresonance points. In my case, the coherence is showing a noisy wave shape or like a thick dense phase graph. I've been trying to hit the same spot as uniformly I can. What is the cause of this result?
Thank you.
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Some things to check:
How does coherence look like? If close to 1, then there is a nearly linear relation between input an output, if closer to 0 then maybe something wrong with your measurement setup (bad SNR?) since
SNR = gamma²/(1-gamma²), with gamma being the coherence.
Bad SNR can be due to the fact that the eigenmode (at a certain eigenfrequency) is not "excitable", i.e. you hit it at a node, not at a point of maximum amplitude, or your acceleration sensor has bad "observation", i.e. it likewise sits at a node of this mode and not at a point of maximum amplitude.
You might also want to check the APS (Autopowerspectrum) of the hammer pulse. Depending on the hammer tip you are using, you will be able to excite a different distribution of energy, i.e. more energy at lower frequencies for low stiffness tips (like rubber) or higher energy at higher frequencies for higher stiffness tips (like hard resin or metal). The shape of the APS of the hammer pulse will show you the details.
Regarding windowing you should also be careful to choose rectangular or exponential for the hammer pulse (and the response). Do not use Hanning or Hamming windows, since they will "fade-in and out" the time signal and you loose too much energy of the hammer pulse (which sits at the start of the window).
There are some good commercial programs available like Head Acoustics Artemis, LMS, etc. that support you in doing it right.
Hope this helps (or is it all known?)
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The non-linear response of the electron in the driving laser field, we always mention in solids, inter-band polarization, and coherent intra-band dynamics of the electron. I want to deepen my understanding of the coherence related to the electron dynamics in the intra-band.
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Bant içi yapısını malzemenin yapısı ve atomik yapısı hakkında bilgi sahibi olduğunuz kadar hayal edebilirsiniz.
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Hello,
I have a technical question in my rectifier fabrications:
Actually i am trying to fabricate one rectifier that operates at 900 MHz (GSM band) and the second one operates at 2.45 GHz (WiFi Band). The one at 900 MHz, the measured S_11 is coherent with that of simulated, however the measured S_11 of the rectifier at 2.45 GHz always shifts to the left at 2.38 GHz. I literally tried everything to technically fix this problem. Does anyone have gone through this problem at higher frequency?
PS: The types of diode packaging and the capacitors in the rectifiers are 'murata' and the matching network is designed by distributed components (with stubs and microlines).
Thank you in advance for the help,
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Hello,
Which diode are you using? Are you using the generic diode model with SPICE parameters?
If you are using the SMS7630 diode and employing the generic model with SPICE parameters, there might be an offset. To eliminate the offset, you would need to establish a surrounding diode model, for example, with a TRL calibration kit. This will provide the correct diode impedance at different operating points (power, frequency, bias voltage).
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overall strategy and analytical approach that you have chosen in order to integrate, in a coherent and logical way, the different components of the study, thus ensuring that the research problem will be thoroughly investigated.
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I would first suggest exploring the sustainable materials that can be used for making products and what process is most sustainable for producing those products/forms.
What usage of the pots do you wish to address? Whether it is aimed at residential use or commercial uses.
Living art is another construct that needs to be explored. is it the end product of the plants and pots together that produces a live and dynamic installation or the concept of 'live' is limited to the organic plant entity?
Once there is substantial knowledge and clarity about the methods and constructs and the domain whether residential or commercial, the next step of designing a questionnaire for the residential/commercial users can be drafted. Which is followed by some ideation and conceptual design activity.
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Atmospheric imaging especially ionospheric irregularity imaging with radar interferometry.
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Aynı tutarlılık ve fazda o günün atmosfer koşullarında oluşturmak mümkün. Işık spektrumları sayesinde oluşturulan anlık görüntüler o zamanın atmosfer koşullarında elde edilen şekil veya boyutlardır.
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I got inspired by the lecture of Deepak Chopra, Jack Tuszynski et.al about the importance of quantum entaglment for understanding of consciousness.
And then I had found the paper by George Rajna
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I totally agree
that also my way of thinking
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Some Iron Guard mathematicians and physicists have argued for nearly a century that it is an idol that should never be touched.
On the other hand, for each in-depth question in quantum mechanics they refer to SE and its derivatives to obtain coherent or incoherent answers from Google or elsewhere which often do not allow the questioner to advance a centimeter.
In fact, they didn't understand SE simply because it's not understandable.
These are not my words but these are the words of the giant N. Bohr who invented quantum wave superposition as the only interpretation of SE.
We assume that SE can be greatly improved if it could be rewritten into a 4D inseparable x-t space.
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Please take a look at,
Fall and rise of matrix mechanics.
Researchgate, January 2024.
IJISRT, January 2024.
We hope that it will provide detailed answers to the interested reader.
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How can we demonstrate the efficacy of multimodal composing in enhancing writing skills, particularly in the context of academic writing, given the prevalent skepticism surrounding its effectiveness in improving academic writing skills? are there any methods or techniques of analyzing students' multimodal products to showcase improvement in terms of macro or micro-skills of writing? concerning coherence, content, organization, etc.
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Hello, Nikhil
You can analyze students' traditional academic writing before and after engaging in multimodal projects using measures of writing quality like a rubric. Look for improvements from the baseline in areas like organization, coherence, evidence use, style etc. I also suggest you to consider using a survey. The survey should be addressed for students on their perceived improvements in writing skills after completing a multimodal project. Also survey their confidence levels in applying writing skills to academic tasks before and after. Good luck
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Need help with an unsupervised deep image stacking project. Image stacking is a commonly used technique in astrophotography and other areas to improve the signal-to-noise ratio of images. The process works by first aligning a large number of short exposure images and then averaging them which reduces the noise variance of individual pixels. I have to do this process with neural networks by predicting a distortion field for each image and using a consistency objective that tries to maximize the coherence between the undistorted images in the stack and the final output. I need some learning materials for performing image stacking preferably in python and make a neural network. I already have experiences with training object classification and detection models and have worked on different YOLO models.
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Due to the specific characteristics and complicated contents of remote sensing (RS) images, remote sensing image retrieval (RSIR) is always an open and tough research topic in the RS community. There are two basic blocks in RSIR, including feature learning and similarity matching. In this paper, we focus on developing an effective feature learning method for RSIR. With the help of the deep learning technique, the proposed feature learning method is designed under the bag-of-words (BOW) paradigm.
Regards,
Shafagat
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Alcohol ink what is the alcohol ink coposition? and what is the additive which help in adhestion/coherent property of alcohol ink ?
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Thank you Mr Adnan for your answer
Kindly, can you give examples for blending and fixatives
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We are going to use the Heidelberg OCT Spectralis for mouse OCT acquisition. However, we find several papers reporting the use of this instrument for rodents, we are not able to successfully do it. We have two separate devices (1- Heidelberg OCT Spectralis and 2- Heidelberg Hra 2). The Heidelberg OCT Spectralis has two lenses one 30° Standard Objective Lens and an Anterior Segment lens. The Heidelberg Hra 2 has 55° widefield lens. unfortunately, the 55° lens could not be assembled to Heidelberg OCT Spectralis.
As far as we know, given the high dioptre of the mouse eye, we should use the 55° widefield lens. However, using the standard 30° we get a rather acceptable cSLO image, no OCT image is displayed.
Can anyone help solve this problem? We already tried using an additional lens in front of the device lens but still not working, however, maybe the total dioptre of the lens was not enough.
Also, a paper suggests minor software modifications (using Alt+Ctrl+Shift+O in Heidelberg Eye Explorer software) which we could not figure out how that should be done. (Spectral domain optical coherence tomography in mouse models of retinal degeneration. Invest Ophthalmol Vis Sci. 2009 Dec;50(12):5888-95. doi: 10.1167/iovs.09-3724.)
These are some papers about using the Heidelberg OCT Spectralis for rodents:
1- Quantitative Analysis of Mouse Retinal Layers Using Automated Segmentation of Spectral Domain Optical Coherence Tomography Images. Trans. Vis. Sci. Tech. 2015;4(4):9. doi: https://doi.org/10.1167/tvst.4.4.9.
2- Tracking Longitudinal Retinal Changes in Experimental Ocular Hypertension Using the cSLO and Spectral Domain-OCT. Invest. Ophthalmol. Vis. Sci. 2010;51(12):6504-6513. doi: https://doi.org/10.1167/iovs.10-5551.
3- Giannakaki-Zimmermann H, Kokona D, Wolf S, Ebneter A, Zinkernagel MS. Optical Coherence Tomography Angiography in Mice: Comparison with Confocal Scanning Laser Microscopy and Fluorescein Angiography. Transl Vis Sci Technol. 2016 Aug 18;5(4):11. doi: 10.1167/tvst.5.4.11. PMID: 27570710; PMCID: PMC4997887.
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Hi Danilo. Unfortunately, no. We could only get some preliminary results using TOPCON using 7line raster mode. however, we could not achieve a full field of the retina.
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Hello friends,
I'm working on the partial coherence calculation of a micro lens array(MLA) based system, and first I need to know the NA of the rectangular beam. Conventionally, the beam is a circular one, but when the Kohler integrator is applied the beam is a rectangular one. In this case, how can we calcuate the NA of the Fourier lens?
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NA and sigma for, (2,4) angle =10,(4,6) angle =20.( tall dimensional and tiny dimensional)
For example rectangular NA=0.37 and sigma=0.5 application.
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Hi everyone!
I'm looking for some exciting analysis methods for correlation, coherence, causality, etc. that can be used for physiological signals (time series, particularly RR time series) obtained from two subjects.
The case study that I consider is: is there any connection between the RR time interval series between a player on the instrument and the listener?
One of the methods that I want to use is the time-frequency coherence analysis by Orini et al. where I will take to input two RR time interval series (from the player and the listener).
What else can I use for this type of data? Do you have any recommendations?
I'm also interested in creating a connection network between players and listeners using the RR time interval series obtained from participants during a music session. However, I don't know what measure for such a graph will be good. It will be nice to create a network like in the Ivanov et al. methodology https://www.nature.com/articles/ncomms1705, not within a body but between the participants. What do you think?
Thank you for every suggestion.
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Mahdi Khorsand Ghaffari thank you for that suggestion! It could be very interesting. I don't know if the EEG signal from the heads of the players who are moving during playing would be good enough for tracking the brain waves, but maybe some good mobile EEG monitors would allow us to collect a good quality signal.
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Hi, I’m a beginner in satellite image analysis. I want to know the lat/lon coordinates of some bursts of a sentinel-1 image. I looked at the file names of the downloaded zip, but couldn’t find any promising files(attached: file structure). Can someone teach me how I can obtain them?
Context: My purpose is to generate a coherence image and project to QGIS. I used SNAP following up to p12 of this tutorial(https://step.esa.int/docs/tutorials/S1TBX%20TOPSAR%20Interferometry%20with%20Sentinel-1%20Tutorial_v2.pdf). but the coordinates were somehow lost from the first step(importing and choosing bursts so as to produce a split file). not sure why but it apparently happens with other satellites(https://earthenable.wordpress.com/2016/11/21/how-to-export-sar-images-with-geocoding-in-esa-snap/). I was able to produce the coherence without coordinates, so i’m thinking if I can get the coordinates from the sentinel file, I can just add it to the geotiff myself.
I also want to ask, is this idea wrong? are the sentinel coordinates different from the coherence image as it undergoes back geocoding?
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Maybe you should study the SENTINEL-1 PRODUCT DATA TYPES.
Candidate Reference:
Regards,
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How if a typical ED (Erbium-doped) fiber can be used as a CPA (coherent perfect absorber) for certain absorption Laser frequencies, e.g. 532nm, 650nm?
Or, if one can devise a ED fiber being the exact opposite of the laser process, i.e. make a design that we termed a CPA for certain application such as Raman Spectroscopy. My understanding is that the CPA can perfectly absorb incoming coherent laser light with given frequency and turns it into some form of internal energy — EM heat or energy.
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Over the last few months, just got learned more about the essence of possible implementation for the CPA fiber material, though it has not been proven yet.
Practically, while PM fibers are designed for maintaining polarization states, turning them into CPAs requires careful consideration of both the fiber's and the incoming light's properties. Given that the field of CPAs is still in its research stages, implementing it in PM fibers would require a deep understanding of both fields and might necessitate significant research and development.
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Although people are trying hard to unify gravity with fundamental forces, gravity should also relate, (derive from a Common parental entity of phenomena or theory) to the fundamental 0henomenon of radioactivity.
This connection has been sidelined, due to irres9lvable lack of Common deniminators and has not seen any funded proposal, to my knowledge.
This should change if we want to be honesty and responsible to our aim of ultimate unification and atrival to an allencompassing, coherent theory of nature or physics of it, there off.
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If gravity is well defined as is in reality... Gravity is connected to electromagnetic phenomena of course can get the connection between gravity and radioactive phenomena/effects.
I have the resolution...
My concept has the next prediction: Take a relatively rapidly beta-decaying radioactive element in a very thin and strong insulating box, on the outside we will experience an effect that increases the moment of inertia.
t can be proven exactly experimentally
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Pseudo-intellectuals (often spelled as "pseudo-intellectuals") are individuals who try to appear intellectually superior or knowledgeable but lack the genuine depth of understanding or expertise in the subjects they discuss. They may use complex or technical language, make references to scholarly works, or engage in intellectual discussions, but their knowledge and understanding are superficial or based on misinterpretations. Pseudo-intellectuals often seek to impress others with their supposed intelligence or intellectualism, but their ideas may lack coherence or substance upon closer examination.
Source: ChatGPT
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Sometimes at conferences (research rather than bladder and bowel) I have met people who create an image and that's all it was. I hope that when I used to be talking about what I considered that I was knowledgeable about, I could talk for ages, but if someone mentioned something that was new to me, I'd be really interested and if it was linked to what I was knowledgeable about, I could continue the discussion from my perspective. But I would be open about the gaps in my knowledge. This was sort of conversation was great, but if the other person did not have much knowledge to back up his / her argument, I was very disappointed.
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Psychological theories are scattered and lack sufficient coherence. Researchers have worked without attention to each other. These valuable theories, if they are put together, find great value. isn't it?
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I think not only the theories of learning and development, the theories of various schools of psychology can be integrated into one theory.
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In optical wireless communication, there are two main system architectures:
• Intensity modulation and direct detection (IM/DD)
• Coherent modulation/detection
In IM/DD systems, the optical front-end can only detect the optical intensity while coherent receivers can detect both amplitude and phase.
Discuss how we can benefit from Integrated reflective surfaces in IM/DD and coherent optical wireless systems. For each system type, explain your underlying assumptions and any other essential information to support your arguments.
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In optical wireless communication, there are two main system architectures: Intensity Modulation and Direct Detection (IM/DD) and Coherent Modulation/Detection.
Intensity Modulation and Direct Detection (IM/DD): This architecture utilizes an intensity-modulated optical signal, which is transmitted through the channel. At the receiver end, a photodiode is used to detect the signal, and an electrical signal is recovered using a transimpedance amplifier. The recovered signal is then processed using digital signal processing (DSP) techniques to extract the transmitted information. This architecture is simple and cost-effective, but it has limited performance due to the presence of noise and other channel impairments.
Coherent Modulation/Detection: This architecture utilizes coherent modulation of the optical signal, which involves modulating both the amplitude and phase of the optical carrier. At the receiver end, a coherent detector is used to detect the signal, which involves mixing the received signal with a local oscillator signal. The electrical signal is then processed using DSP techniques to extract the transmitted information. This architecture provides better performance than IM/DD, but it requires complex hardware and is more expensive.
Both architectures have their own advantages and disadvantages, and their suitability depends on the specific application and performance requirements. IM/DD is suitable for short-range applications where cost and simplicity are important factors, while coherent modulation/detection is suitable for long-range applications where high performance is required but at a higher cost.
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Physics started as natural philosophy then became a science but one should not forget to explore its nature as it evolves ..and the realist element is undermined in my view.
Most theories are evaluated based on their alignment with this philosophy, i.e. not based on conceptual or logical coherence but based on realist connotations i.e matching the world, lakcing implicaions that are absent in nature.
Other philosophies complement physics, like conventionalist or relationalist but realism is the defining one and in my opinion has been interchangably, albeit not admitedly, used as a reference for what physics stands for.
In my work "Predictability in physical sciences" (available on my profile) i touch sone aspects of realism, mainly via its expression in oredictability pursuit, which is an overdue aim in physics, thus painting another argument for this thesis: physics is equally a science and a philosophy of realist criteria focused truth seeking
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And ar you affirmstivevwith the thesis that physics is in fact a realist philosophical approach to natural world, using such a framework to discern truths from not truths and not any other i. E mainly pragmatist or conventionalism or rationalist?
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I want to detect photon at high quantum efficiency. I know that PMT (photo-multiplier tube) can do that, but I also want to get the frequency of the signal (like MHz accuracy). Is it possible to use stimulated emission to multiply photons (avalanche effect), and then feed them to a spectrometer or coherent heterodyne device?
I currently find nothing about this in literature. Is this idea impossible for some physics or engineering reason?
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Fotonlar yüksek kuantum verimliliğinde çok hassas frekanslara sahip olurlar. Fotonlar yüksek kuantum verimliliğinde fotonla uyarılır ve yine yüksek kuantumlu fotonlarla beslenir.
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Our answer is certainly YES.
Albeit, in spite of experiments, some supposedly highly-qualified people think that even quantum computing (QC) makes nothing unlimited.
They also say that due to (magical, no one defines it coherently) superposition, exponentially (and more) speed up algorithms can exist but … nobody has shown that it can indefinitely speed up algorithms.
What can one say to that? Would it be helpful to have a manuscript that shows things can be calculated unlimitedly? Only using B={0,1} ?
What is your qualified opinion?
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New text was added to the prime flower posting above, clarifying questions that I received by both public and private messages. Every tool by RG finds its right use ...
Trans-human communication includes not just extraterrestrials (that naturally exist, or it would be a terrible waste of space and time).
Plants also show prime numbers in nature, communicating with insects and humans. See figure in that comment.
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Dear Friend and colleagues please share your views on importance of coherence in leadership. How much it justify leadership personality. In absence of coherent approach what draw back leaders face.
Thanks & Regards
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In my work applying negative dialectics to understand how we might better realise an emergent future, I see coherence as the essential link between the present, the adjacent (future) possibilities and the emergent future. Here, leadership has a key role in developing and maintaining that essential coherence. It is leadership that are the custodians of the adjacent possibilities and who must guide our emergence to best effect.
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I want to make two coherent light sources in phase using one laser source. It can be done by using a beam splitter.
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Well, that’s not really possible. The problem is that for any laser the phase wanders randomly over time compared to an absolutely perfect frequency reference. The more stable the frequency and the narrower the line width the slower the wander, but the phase will wander. For two sources to wander around together they have to be tied to the same random walk. That can mean splitting a single source, or it can mean seeding two sources with the same seed laser. It can also mean actively driving the phase of different sources to match that of some reference source. However, in all cases one way or another all outputs are tied back to one reference source.
Now, if you make two independent sources, their phase difference will stay constant for something like whatever the shorter coherence time of the two. However, while you can expect the phase difference to not drift much on time scales short compared to the coherence time, at any given moment you have no idea what that phase difference is and it will wander through all possible values on a time scale long compared to the shorter coherence time. So that lack of knowledge or control of the relative phase prevents you from doing all the things we do with coherent sources. Yes they are coherent for useful lengths of time, but with an unknown and varying phase difference.
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My Awesomest Network, I am starting my Ph.D. studies and I have some questions and doubts concerning it. Could I write them down here, please? First of them is how can I join disciplines as sociology, management, economics, mathematics, informatics and other similar items to make a complex holistic interdisciplinary analysis and coherent study of pointed fields. I think personally that linking or joining et cetera aspects of artificial intelligence and computational social sciences would be interesting area of considerations. What are Your opinions?
Thank You very much for all in advance
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The Aidos-x system is an excellent intelligent system for diagnosing and classifying human diseases. The methods of using the Aidos-x system for diagnosing human diseases are disclosed in lectures with sound "Using automated system-cognitive analysis for the classification of human organ tumors", "Intelligent system for diagnosing early stages of chronic kidney disease", which can be downloaded right now from the website https ://www.patreon.com/user?u=87599532 Creator's title: «Lectures on Electronic Medicine». After subscribing to this site, you will receive databases for medical research to identify the diseases that you will read about in lectures. The acquired skills of working in the Aidos-x system will allow you to apply for grants to carry out scientific research in the field of medicine.
To subscribe to the site https://www.patreon.com/user?u=87599532 you do not need to go to the bank, but you can do it using the Pay Pal system. Send a transfer in your currencies, and the transfer to dollars will be done automatically. After subscribing on the site, you will receive the Aidos-x system with an English user interface for free.
Thank you.
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I work with an optical coherence tomography system. I want to detect the boundary between two features in an OCT image using a CNN. Kindly guide me to anyone who has done similar work or published work on this problem.
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Actually, there are many tools that you can develop the code. But when we talk about the CNN, it about the long journey of learning. It cannot get on the spot. Maybe you can read some intro what is machine learning, what is deep learning.
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My Awesomest Network, I am starting my Ph.D. studies and I have some questions and doubts concerning it. Could I write them down here, pleaswe? First of them is how can I join disciplines as sociology, management, economics, mathematics, informatics and other similaer items to make a complex holistic interdisciplinary analysis and coherent study of pointed fields.
Thank You very much for all in advance
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Thank You for an opinion!
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How can I change the phase coherence of an image with a specific amount?
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The Fourier Transform of an image can be decomposed in two components, its power spectrum (the square modulus of each Fourier coefficient), and the phase (the argument of each Fourier coefficient).
Regards,
Shafagat
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An educational workspace could be a school, university, or any team that works in the education, or training field.
This question addresses particularly t the educational manager but meets also any manager's interests.
Once upon a time, while I attend training about leadership, my mentor said to me: you have to create a team. I thought that I had a team, replied, and he said you don't have a team, you need to build it. At that time, I don't really understand what he meant. And I should continue with a group of coworkers and never had a team. When the team doesn't exist you have to fight for anything as collaboration, outcomes at the right time, sharing experiences, etc After three years, in a new office, I became again a team manager, but I didn't especially create this team, but I think I consolidate the team that I inherited from the circumstances. Nevertheless, I think I gave a good contribution not as large as the executive management who had the power to decide whether to recruit or not the profile that I suggest, but it matters.
So, I would like to get others' experiences to compare and reinforce my experience at work; also writing a scientific article.
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I hope the following attachment helps you
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Coherence and correlation seem very similar to each other to me; while, coherence assesses similarity of the signals in frequency space rather than time space. I was wondering whether it is possible to employ coherence instead of correlation in Canonical Correlation Analysis.
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I have the same feelings with you that coherence can be a better criterion for SSVEP decoding. Do you have any progress on the coherence bbased SSVEP decoding? Thanks.
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I need an exemple of the wavelet coherence and cross spectrum please.
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You Welcome, Karim Bouhali
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In text and linguistics, how coherence can be utilised fully? What are the advantages of coherence?
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请你看看中国语言之中的修辞,回环、顶针……接龙,那些都是
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Hi guys,
I am using the negative log likelihood function of a drichilet distribution as my loss function while implementing this paper:
I parameterise the distribution using my network outcome and compute the negative log likelihood of the observed ground truth.
Issue is that I found sometimes the loss is negative, which means that likelihood at the point of observation is greater than 1.
My understanding of this phenomenon comes with two sets:
- This is normal, as likelihood function can be higher 1
- This stands for overfitting, means that the likelihood function probably peaks at the point of the observation so much that other areas of the support would be zero, if we throw an observation there to be test
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I would suggest that you are probably using a poor method of fitting. Please look at the entries on the attached Google search. Good luck David Booth PS I note that R has procedures for doing this fit.
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Hello everyone. Some of us are not experts in psychology but we are interested in the subject and we want to have some basic ideas to help our students. I have some doubts about the similarities and differences between some concepts. I am referring to Dabrowsky's over-excitabilities, Aron's highly sensitive persons, the concept of giftedness itself and the aftermath of post-traumatic stress. There are experts who confuse these terms, deny the validity of some of them, consider them synonymous, etc... I would like to have a coherent explanation as to whether they are related aspects or whether some encompass others. Thank you very much.
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Thanks a lot Béatrice.
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Cold plasma is characterized by a thermal non-equilibrium between heavy particles (ions, meta stables, neutrals) and light particles (electrons),and is characterized by a low current discharge under atmospheric conditions, generated by application of high voltages.While the most common laser output characteristics include: wavelength, gain bandwidth, monochromatic, spatial and temporal profiles, collimation, output power, coherence and polarization.
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Dear Virendra Nath Rai
Thanks you
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Lasers are well known for their coherency. I was wondering to ask whether it is possible to make white light coherent? Of course, a long coherency length the same as lasers is not intended/expected but a coherence length of 10-30 cm.
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Arman Arefi a coherent, continous white light beam is pretty much a self-contradicting statement.
If light is coherent and white, it comes in pulses.
If light is coherent, but does not come in pulses, it is not white.
If light is white and does not come in pulses, it is not coherent.
Pick one.
Note that femtosecond lasers can often have high repetition rates - 70-80MHz, or in special cases even multi-GHz. For some applications, a source with this high repetition rate may work as a quasi-continous source. For others, of course, this may not be the case.
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I started working on coherence and entanglement. At a point, I became confused between the concepts of entanglement and coherence where an author texted it the same however, they are still considered different by many authors. If anyone can explain, please answer this
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What quantum entanglement? considering that it is possible to identify (and distinguish!) between a mathematical (or spurious) entanglement and a physical entanglement. Identification of a mathematical entanglement (in a mathematical model) does not necessarily correspond to the existence of a corresponding physical entanglement (in a quantum system).
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Assuming there are TWO HeNe coherent laser sources one with LP and the other with Random polarizations (RP). l can see clear fringe pattern if LP light source pass through aligned-fringe pattern MZ interferometer (I had only a LP HeNe laser in my Lab). Is there any difference if take the coherent RP HeNe Laser source for doing the same MZ test? Why?
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Throughout the entire path of the interferometer is light is a collimated plane wave. We can arbitrarily pick two basis polarizations. Let’s choose the two linear polarizations that are S and P at the mirrors of the interferometer. Any other arbitrary state can be described as a supposition of these two. Provided the sample itself is neither a retarder nor a polarizer, the two polarizations do not interfere with each other. Each polarization is effectively a completely independent MZ interferometer experiment. Either polarization produces the same interference pattern. Therefore any superposition of the two polarizations produces the same pattern.
A randomly polarized laser wanders in time over all possible linear combinations of the two polarizations. However, at any instant in time the polarization is well defined. The two paths arriving at the screen are from two slightly different moments in the lasers history depending on the difference in length of the two arms and the path length difference introduced by the sample. For the interferometer to work this path length difference must be less than the coherence length of the laser. It must also be small compared to how quickly the random polarization changes. However those two things are not independent. Since orthogonal polarizations do not interfere, the rate at which the polarization changes is part of what determines the coherence length.
So, basically, if the coherence length is long enough for the interferometer to work, then the polarization state is changing slowly enough to think of the interferometer as being in some particular polarization state at any moment. All superpositions of the eigenpolarizations produce the same interference pattern, so the interferometer works fine with randomly polarized light.
Now, if the sample is birefringent or polarizing, things get more interesting.
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As being an amateur Quantum Optics researcher, I am looking for RG's help with comprehend a few questions re. my fiber Labs.
1. Assuming HeNe laser sources with LP and Random polarizations (RP), let such lights pass through aligned-fringe pattern interferometer (I had only done LP laser). Is there any difference in the TWO sources' output interference patterns? Why?
2. A LP free-space Laser source's MFD and waist get well aligned with a PM fiber coupler (slow axis is in vertical). How and why will the PM fiber coupling ratio (%) be varying with the different polarization incidence angles, e.g. Vertical, Horizontal and Diagonal?
What will be their output characteristics at the PM fiber output end in terms of polarization states?
3. To control a SM fiber output polarization, it can be done by using a fiber-stress type polarization controller. How if I can or cannot control a PM fiber output polarizations by using such controller?
4. How if a typical ED (Erbium-doped) fiber can be used as a CPA (coherent perfect absorber) for certain absorption Laser frequencies?
Or, if one can devise a ED fiber being the exact opposite of the laser process. In turn, make a design what we term a CPA. The ED fiber device perfectly absorbs incoming coherent laser light with given frequency and turns it into some form of internal energy — EM heat or energy.
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The incandescent light source is not considered a coherent source.
This source has a very short coherence time, and you cannot consider it a thermal light though.
another how it could HeNe laser and randomly polarized at the same time!
honestly, I cannot see how could please explain how it is a laser system and randomly polarized.
if you are going to use a thermal light the fringes will be washed-out.
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We synthesized sin waves in matlab. One pair data are at same lower frequency and same lower power. The other pair are at same higher frequency and same higher power. There are high coherence within both lower/higher frequency pair, because they are almost same in the each pair. But if I mix lower/higher frequency/power together and calculate coherence, the higher frequency showed high coherence, but the lower frequency showed low coherence, although the signal in lower freq should be very coherent! I feel something is wrong with power normalization.
The attached is my matlab file. we used mscohere. BTW would wcoherence be different?
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You have to be carful with modelling coherent waves.. you need to begin with certain spectrum width at the start. It will ensure coherence parameters. starting with two or three coherent waves is not correct. there is always a spectrum of few contributing waves. the right way of modelling is spectrum and it’s width.
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I was reading a paper introducing the Delayed Self-Heterodyne Interferometry technique by Okoshi in 1980. It was aimed to measure the linewidth of lasers and the main set-up was something like a Mach-Zehnder interferometer, but one of the arms was delayed by a fiber path much longer than the laser's coherence length, and there was an AOM in the other arm [I don't know if it's important]. The interference of these two beams was claimed to indicate the linewidth of the laser. What I do not understand is that how these uncorrelated beams do interfere?
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For the coherence time the laser’s frequency and phase are stable(ish). Interfering two snippets of the laser from different times, they may have different frequency and phase, but for a coherence time the frequency and phase of each is well defined and they will interfere producing a beat frequency. After a coherence time their phases or frequencies will have drifted enough that the beat frequency and phase drift. However, if the coherence time is longer than your detector bandwidth, you have already recorded the beats that happened during that coherence time. The beat frequency and phase will drift through all possible relations presented by the bandwidth of the laser, but it will all be recorded in the time record.
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Hi,
I'm interested in running periodic ab-initio simulations of a disordered alloy using Quantum Espresso. I noticed that in most recent publications disorder is usually introduced with the coherent potential method (CPA). However I am not really sure how CPA and QE can be coupled together to effectively run the simulations I want.
May I ask you if any of you have already used CPA and QE together and, if so, how can CPA be correctly incorporated in a usual QE routine?
Thanks in advance,
Best,
José
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Many thanks, Abhinav Nag . I will try SPRKKR code
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Hello researchers,
I have around 100 sentinel-1 SLC images. I want to compute coherence between the successive images (1->2, 2->3… and so on). For this, the conventional method is to read images 1 and 2, select swath, apply orbit files, coregister them using the back-geocoding operator, apply ESD and then compute the coherence and the same procedure is also with images 2 and 3, and so on.
I want to discuss another approach here
  1. Read image 1 and coregister all other images (2,3,4…100) with respect to 1.
  2. Now, for images 1 and 2, we can compute the coherence as the above-mentioned method.
  3. For image 2 slv and image 3 slv, we stack them together considering them already coregistered with image 1 and compute coherence.
I want to understand whether it is an ethical way to do it or not.
1. Can we assume in the case of SAR SLC product image 2 and image 3 are also coregistered when they are coregistered with image 1?
2. Do different incident angles affect the coregistration results?
3. Is there any effect of different range and azimuth pixel size? 4. What should be the optimal method to perform successive time series analysis?
Thanks
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I would suggest using isce2 stack processing (https://github.com/isce-framework/isce2).
you may find the tutorials at https://github.com/isce-framework/isce2-docs.
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Dear all,
I conducted a mediation analysis with PROCESS obtaining the following results:
- path a (x on M): significant and negative. Coherent with my theory
- path b (M on Y): significant and positive. Coherent with my theory
- Path c and c': insignificants
Indirect effect: significant and negative.
Is it correct to comment on this result in terms of fully mediation? however, extensive literature defines mediations in which the coefficients of a and b have opposite signs (and/or in which the total effect is not significant) in terms of inconsistent mediation. Should I interpret my results in these Terms even if they are consistent with what I expect?
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بالتوفيق
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I have an EEG dataset that contains 62 databases of 27 subjects, recorded from 32 channels.
how can I compute coherence or correlation of channels (in whole of dataset)?
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Use the ' conv(A,B) ' in MATLAB to calculate the Cross-correlation. A and B are two different signals. Use the ' Y=fft(A,n) ' command to calculate the FFT of a signal. The A is the signal in the time-domain and the Y is the same signal in the frequency-domain. The n is the number of points we want to calculate the FFT.
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Does quantum coherence relate to one particle?
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Despite having the same roots of origin, namely quantum superposition, coherence and entanglement are conceptually different.
For example, coherence can be present in single quantum systems, where entanglement is not well-defined. Entanglement shows a correlation between the pais of photons where changing the spin of one of them will affect their pair photon in a predictible way no matter the how far apart they are, Einsten call this: "spooky action at the distance"
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The Wavelet Coherence Approach has frequently been used in the time-series analysis. How can one apply this technique in MATLAB. Suggestions from expert users are highly appreciated.
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Wavelet Toolbox™ provides apps and functions for analyzing and synthesizing signals and images. You can detect events like anomalies, change points, and transients, and denoise and compress data. Wavelet and other multiscale techniques can be used to analyze data at different time and frequency resolutions and to decompose signals and images into their various components. You can use wavelet techniques to reduce dimensionality and extract discriminating features from signals and images to train machine and deep learning models
Regards,
Shafagat
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If we apply atmospheric correction to the data to enhance the coherence, will it provide accurate deformation result in a densely vegetated mountainous region like the Himalayas.
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Thank you very much for this interesting question. This indeed is a research question that can only be answered after thorough research. While I was searching for some answers, I came across the attached publication. I hope it provides some insights.
Thanks and regards
Gowhar Meraj
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I want to know the calculation for following paper. I am attaching the paper. Please help me
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I normally use the SLC data of sentinel 1 data for calculation of repeat pass coherence. Is there any platform to access InSAR repeat pass Coherence data without needing the original SLC data?
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The Alaska Satellite Facility (ASF) offers a free SAR processing service - Hybrid Pluggable Processing Pipeline (HyP3). HyP3 provides two types of data:
  • Radiometrically Terrain Corrected (RTC) Sentinel-1;
  • Interferometric SAR Sentinel-1 (contains interferogram, coherence and displacement map, among others).
The quota is 250 tasks per month per user.
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It is well known that femtosecond CARS signal can be further enhanced when the condition of electronic resonance with the involved probe pulse is satisfied. Where can I find the relevant formula that quantitatively describe the ehancement ?
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I agree with Pooja Singh.
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Globally, air shed management and planning has resulted in viable and constructive solutions to address urban air pollution. Real time monitoring of air pollution based on the data pertaining to the part of the atmosphere that behaves in a coherent manner with respect to dispersion of emission might be critical to comprehend the air quality of a place. I would like to invite a discussion on this aspect of pollutant dispersion.
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The detection was of uv-vis thru a traditional double convex (glass) lens.
Can a parabolic reflecting lens focus and detect RF with this same coating, or stereoscopically 2 parabolics, with sufficient amplification ?
Detection of uv-vis with these metals of low work function is by the photoelectric effect.
But what was the phenomena of Marconi's transatlantic detection of RF (and its associated keyed Morse CODE) by the silver nickel powder "coherer" in the circuit?
Are there electrical component specifications for the coherer (V, I, R). The electrical schematic produced by Google searches shows a DC circuit with an Antenna symbol and other recognizable elements, but the "coherer" is not symbolized but is a 2D sketch of what it actually looked like.
Note: The lay word for parabolic is "dish".
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hi,
The electrical parameter Resistance is the measurable quantity which undergoes changes as the ferrous particles of the coherer are exposed to the impinging electromagnetic field. Even though google may not show any particular details, one can just measure the DC resistance (DC circuit with an antenna) to detect RF signals using coherer. If you use metallic parabolic reflectors and place the coherer at its focal point, the signals will be highly concentrated on it. This will to see the changes in the resistance value relatively with an ease.
Regards
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In GP practice, a balance has to be found between limited time and enabling sufficient mutual understanding. One criterion could be the practitioner's feeling of having understood the subjective logic (world view) of the counterpart. What do we know about such a feeling of practitioners?
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Dear Julius,
Thank you for your answer and for asking me to clarify my question.
First of all, my question refers to the work of family doctors. I am collecting arguments and literature references for updating a recommendation for action by the German Society for General and Family Medicine on the initial interview. The previous version contains the recommendation that in addition to the exploration of the general physical condition, any current complaints, existing risk factors and already manifested chronic diseases as well as the diseases that have already occurred in the family, the current life situation (work, family, housing, etc.) and central aspects of the biography should also be found out. This should be done in order to exclude foreseeable dangerous courses and to develop an overall understanding of the patient, which can guide the development of the relationship and the joint treatment. On the part of the group of authors, we argue that it is worth investing in the beginning - the initial interview - whereas many practitioners argue that in the course of long-term treatment, the relevant life-world-related and biographical data can gradually emerge (" lived anamnesis") or gradually be recovered. In Germany, a maximum of about 20 minutes is available for initial interviews, so the question is when it is "enough". In my experience, information is often collected whose meaning remains unclear from the patient's point of view - does "living in family" mean having social support? Or, in the given case, does it mean quite the opposite, that there is constant tension? Therefore, we thought that "the practitioner's feeling of having understood the patient as a whole person" could be a central criterion. It is clear that this feeling depends on experience and the like, but we assume that it also becomes action-guiding when the practitioner is not aware of it.
Apart from the breadth of possible problem situations, the time frame available for the conversation and the possible long-term relationship as special features of general practice, I think the question can be transferred to other situations.
What do you mean?
All the best
Ottomar
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I read a paper address that "The effect of elastic strain energy is neglected in the model since the precipitation of sigma phase is simulated only in base metals where there is no coherency between austenite/ferrite." I don't understand this, how can we know whether there is coherency between phases? thanks for your answering
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It is not that simple. The boundary is not always incoherent. If the microstructure contains Widmannstatten ferrite, then there is a coherent, or semicoherent boundary between this ferrite and austenite.
The nature of a boundary between phases, of which one is the result of a precipitation process, depends on several factors, primarily on the difference in the free formation energy of both phases, on the grain boundary energies and on the rate of movement of the respective grain boundaries of the precipitated phase.
These physical factors, in case of steel, depend on the composition (carbon content) and the cooling rate.
For a more comprehensive reply and understanding of the physical principles, I suggest to read the book: Phase Transformations in Metals and Alloys, third edition, by D. Porter, K, Easterling and M. Sharif, CRC Press, especially page 299 onward.
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Dear all,
I am performing Wavelet Coherence analysis using R package biwavelet. But as soon as I run the command wtc.t1t2=wtc(t1, t2, nrands=100), I am getting error: Error in arima(d2[, 2], order = c(1, 0, 0)) : non-stationary AR part from CSS.
1. Need guidance to get rid of this error.
2. Is there any limit to the number of observations in the series? (in the above command t1 and t2 have 43 observations each)
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Thanks Iftikhar Yasin for sharing the sample file. TI learned that some data may cause this problem. The wtc function uses another function arima which checks with both coefficients to be between -1 and 1 so that the process would be stationary. If not, it throws the error you are experiencing. This can be solved by using the argument method = "ML" in the arima function itself. The ML stands for maximum likelihood and it forces R to perform the task. For your convenience, I have modified the script and pushed it to my GitHub account. The following link provides a script that you can copy and paste into R for execution. Afterward, instead of wtc, use wtc_Modfd. You can leave the rest as it is. Please let me know if there is any difficulty. Thanks
# Use it as
wt1 = wtc_Modfd(t1, t2, nrands = nrands)
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I am trying to investigate the coherence between two shoulder muscles at 0 - 90Hz. Precious studies used various cuff-off for their band pass filter, e.g. 1–400 Hz(Chen, 2012), 5-300Hz(Boonstra,2008), 3-1000Hz (Kattla, 2010). How do I determine the most appropriate filter for my analysis?
Also, we measured both surface and intramuscular EMG, but some intramuscular EMG signal are not good. Is it acceptable if I downsample the intramuscular EMG of one muscle, and calculate the coherence between it and the surface EMG of another muscle?
Thank you!!
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J. Rafiee
Thanks for your help!
Some of my intramuscular EMG data was 'not good' because the fine-wire slightly moves during muscle contraction. For subjects with more fat at their back, getting a nice recording will also be challenging.
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I want to impute my data set in R by hmisc method, but I am failed as it is not recognizing my file and any command I am applying to impute the data, as I want to impute the whole data set as soon as possible. Is there any easy way for that?
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Muhammad Usman thank you so much , files have been opened
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For thin-film interference, the pulse duration is too short that the a part of the light can't meet the other part due to round-trip delay. In other word, part 1 can't reach the top surface part 2 while it's still lasting at the top surface within the source-on duration.
So if the chopper cut the CW light into pieces and changes the spectrum to a wider spectrum, will that mean temporal coherent length is relevant to pulse duration?
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Michel's last sentence is exactly what I'm referring to in my gas-tube HeNe example. Over the time duration of a single pulse, the light is temporally coherent; however, correlated pulse to pulse (depending on the pulse repetition frequency compared to the coherence time), the light is temporally incoherent.
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In File 7 of ENDF thermal scattering sublibrary, the coherent elastic cross sections of solid polycrystals are all for powdered samples.
Texture in the solid samples will affect the Bragg scattering cross sections. The structural materials in reactors are not powdered samples. I wonder is it reasonable to use the coherent elastic scattering cross section for the powdered polycrystal in the simulation of reactors?
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What do you mean by reactor?
Coherent elastic scattering of what?
Neutrons and X-Rays undergo Bragg scattering in polycrystalline metals.
As you mention the behaviour is similar to a powder, because of low interaction of the radiation with the material.
Nicolò
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How to define coherent "limits" of technology´s in AI ?
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What is your experience about a more effective aid to teaching university students. Some people believe that PPTs help promote focus and coherence of thoughts of the teacher, others feel that the use of blackboard draws better attention of the audience. Of course, we presume that other things are the same in both cases e.g.competence of the teacher/facilitator, relevance of the contents, infrastructure, and motivation level of the students, etc.
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Dear Prof. Saini!
You pointed to an important topic. I think that now during the COVID-19 pandemic online interactive online handouts with video short movies (cases) are the best way to adapt to circumstances (remote learning). Still this problem is a case - and context dependent one:
1) Lorico DS. Lapitan Jr et al. (2021). An effective blended online teaching and learning strategy during the COVID-19 pandemic, Education for Chemical Engineers, Volume 35, (2021), Free access: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7847201/pdf/main.pdf
2) A case-study: William Flynn et al. (2021).Delivering online alternatives to the anatomy laboratory: Early experience during the COVID-19 pandemic, Clinical Anatomy, Volume 34, Issue 5, January 2021, Free access: https://onlinelibrary.wiley.com/doi/10.1002/ca.23722?af=R
3) Darius, P.S.H., Gundabattini, E. & Solomon, D.G. A Survey on the Effectiveness of Online Teaching–Learning Methods for University and College Students. J. Inst. Eng. India Ser. B (2021). https://doi.org/10.1007/s40031-021-00581-x Free access:
4) Kumar, P., Saxena, C. & Baber, H. Learner-content interaction in e-learning- the moderating role of perceived harm of COVID-19 in assessing the satisfaction of learners. Smart Learn. Environ. 8, 5 (2021). https://doi.org/10.1186/s40561-021-00149-8 Free access:
Yours sincerely, Bulcsu Szekely
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I now explore three pedagogical strategies to improve junior high school students' skills in ESL academic writing. The main things I set up now are: lexical resources, grammatical range and accuracy, and coherence and cohesion. Do you think it works? Do you have any better suggestions for me?Thanks!
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You can consider with discourse can increase the student motivation and activity to write their idea.
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Why fiber rotator is needed in optical coherence tomography system? Currently I'm building a endoscopic OCT system from scratch and the fiber rotator will be used in the sample arm. Since I'm a newcomer in this area, could anybody offer an explanation for this device?
Thank you.
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Well, I never heard of OCT until this minute, but a fiber rotator is generally for selecting the axis of polarization entering (exiting) a polarization maintaining (PM) fiber. A couple minutes with Google and I see polarization sensitive OCT is a thing, so I think that is the idea. If the light source is polarized, the scattering tissue can change the polarization. Different tissues give different polarization effects, so being able to change what polarization you are observing provides extra tissue differentiation and contrast.
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I'm looking for some kind of study, maybe a survey, that looks at where researchers started their work in terms of ideas and where they ended before publishing it. This could be an idea that they had or a reference that inspired them. It is my belief that researchers often try to tie their initial ideas to their innovative findings in a coherent train of thought before publishing it. But it is also possible that the innovation may have nothing to do with what they started. I wish to check if there is a statistical study on this matter, but I'm not sure what keywords would help me find such a study.
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Hopefully the guidance as per the following publications could help:
  • Blackburn, R. and Welter, F. (2014) From idea to publication: managing the research process, in Fayolle, A. and Wright, M. (eds.) How to get published in the best entrepreneurship journals: A guide to steer your academic career. Cheltenham, UK: Edward Elgar Publishing. Inc., pp. 72-93.
  • Blaxter, L., Hughes, C. and Tight, M. (2006) How to Research. 3rd edn. Berkshire, England: Open University Press, McGraw-Hill Education.
  • Fink, A. G. (2017) How to Conduct Survey: A Step-by-Step Guide. 6th edn. California: SAGE Publications, Inc.
  • Summers, J. O. (2001) Guidelines for Conducting Research and Publishing in Marketing: From Conceptualization Through the Review Process, Journal of the Academy of Marketing Science, 29, 4, pp. 405-415.
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Working on chandrayaan-2 DFSAR data, there are three datasets available:
1) Slant range image data product: The slant range complex image file. Each pixel is represented by two 4-byte floating point value (one 4-byte floating point real and one 4-byte floating point imaginary value). Each pixel in the slant range image is Seleno-tagged with a lat./lon. value.
2) Ground range image data product: The ground range unsigned short int image file. Each pixel is represented by 2-byte unsigned short int. Each pixel in the slant range image is Seleno-tagged with a lat./lon. value.
3) Seleno-referenced image data product: The Map projected image file. Each pixel is represented by 2-byte unsigned short int file(amplitude).
Which should I be using if i want to generate coherency matrix and perform target decomposition?
Thanks in advance!
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Piyush Kumar For generating coherency matrix and further performing target decomposition, Single Look Complex SAR data is required which is Slant Range Data Product. So, in case of Chandrayaan-2 DFSAR data, you need to explore SLI (Single Look Image) data. I think that these basic information are available at ISSDC web portal where you might be downloading data sets.
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I am working in wavelet coherence analysis of two variables and I have plotted the wavelet coherence spectrum. But I wanted to find the phase lag and correlation coefficient for different time periods like 2, 2-4, 4-8,8-16, 116-32. Basically I wanted to decompose the wavelet into different time scales. I am using MATLAB for the analysis and I am pretty new in MATLAB coding. Please help me to find a solution.
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One option could be just using windowing or proper scaling filters and performing wavelet decomposition separately if your ultimate goal is to detect the frequency elements in a particular time period. For this option, you might use any windowing algorithm with or without overlap. Another option could be using different forms of wavelet transform. For instance, wavelet package decomposition might give you more flexibility in terms of time-frequency scaling. You might also wanna look at : Maximal Overlap Discrete Wavelet Package Transform (MODWPT) and Double Density Discrete Wavelet Transform (DWT) for better decomposition options.
For more details:
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Hello,
I am doing SIMULATION of TURBULENT PREMIXED FLAMES of CH4/NH3/air in Ansys Fluent. I am using the following:
Partially Premixed Combustion Model; Chemical Equilibrium; Extended Coherent Flame Model; Energy Eq on; Viscous k-e;
I wanted to try with Flamelet Generated Manifold but don't have CHEMKIN Files for this mixture of fuel.
I have Laminar burning velocity from measurements but don't know where to put it? also equivalence ratio (0.9); In Properties Tab of Species Model Fluent is calculating Laminar Flame Speed - how?
Boundary conditions: velocity: 0.41607m/s; Turb Intensity: 16.64%
Please help!
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Agree, GriMech is one of the best libs to calculate such a problem!
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We calculate coherence as the degree of first-order coherence, defined in Eq. 6, Dudley et al., Rev. Mod. Phys. 78, (2006), where input pulse shot-noise is modeled semi-classically through the addition of a noise seed of one photon per mode. From this model, we expect that the coherence depends on the repetition rate, and the coherence will be higher for a high repetition rate. Is that true from a physical point of view?
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For a prefect pulsed laser, the repetition rate will not affect the first-order coherence. Happenly, I have also worked on this noise model of SC generation several month ago. In fact, I have tried to model several kinds of noise such as the quantum noise, technical noise, as well as the amplified spontaneous emission noise. The last one makes us publish some papers. see " Spontaneous emission noise in mode-locked lasers and frequency combs" and " Tailoring the waveguide dispersion of nonlinear fibers for supercontinuum generation with superior intrapulse coherence ". I also wonder what mathematical models you will adopted for noises?
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Professor Selleri's book "The weak relativity" represents the summary of 20 years of research on the physics of space and time. The research path is clear, the arguments are solid, the logic is evident, the content is revolutionary. If the topics expressed in this book are "true" physics would be completely reversed, the SR and the GR should be abandoned, with all their consequences, such as the Big Bang, dark matter etc .. Yet 9 years after its publication, no one has been able to reasonably contrast Selleri's ideas and in the same way no one has thought it necessary to rethink the physics of space and time .......
Either his ideas are refuted in a coherent and rational way or the physics of space and time must be completely re-founded, there is no alternative in the scientific method, indifference is not an option
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The interaction between a two-level system and a coherent field without a cavity does not produce the so-called "collapse and revival". Why?
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The oscillations are the result of energy being transfered back and forth between the photon field and the population inversion. The population inversion has feedback from its own history N round trips ago and that coupling to its earlier self is what causes the oscillations. However, without a cavity there is no backwards coupling between the photon field and the gain population that produced It. Yes photons interact with the population inversion further down the gain medium, but there is no chance to interact with the population inversion where they were produced. There is feed forward, but no feedback, and without feedback there is no oscillation.
Take a simple case of a gain medium with a population inversion with a seed laser entering from the right. Now consider a thin slice of the gain at the entrance. Now write the differential equations. The stimulated emission depends on the population inversion and the photon flux as you may be used to in a cavity. The resonant absorption also has the usual form. What is different from a cavity is that for a very thin slice (limit) the rate of change of the photon population does not depend on the population inversion at all. Any stimulated emission immediately exits the thin slice toward the left. Any stimulated absorption is immediately replaced by the seed laser flux. The seed laser flux may vary in time, but not due to anything that is happening in the gain slice. If the seed laser fluence is constant, the photon population is constant. There is no coupling to the population inversion. There is no feedback to the population inversion to cause oscillations. The population inversion proceeds monotonically to the equilibrium condition.
Now consider another thin slice of gain just to the left of the first. The situation is exactly the same. The “seed” now includes the emission from the first slice, but we know that it is changing monotonically to equilibrium. In this slice once again there is no feedback coupling the photon population to the population inversion. Here again the inversion proceeds monotonically to equilibrium.
And so on for each slice throughout the gain. The entire system proceeds monotonically to equilibrium.
Fundamentally, the oscillations come from feedback. What the population inversion did at an earlier time is fed back into the population inversion at a later time by the photon field. If the photons do not circulate and return to the same place at a later time there is no feedback mechanism to link the population inversion to its own earlier history. No feedback, no oscillations.
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Is there someone who has a research paper?
Preferably for frequencies around 700 Mhz, 868 Mhz, 900 Mhz.
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this pdf>>>>>>
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Do we have any research that scientifically, rigorously or with some level of objectivity measure the structural logic of policies? Or is there anyway measure we use to say that this is a coherent, consistent, congruent policy with integrity (the content)? Or in another way, are there any existing measures one can use to measure the evolution of a policy's causal logic over time?
The existing measure is it also used as an indicator for the potential success of a policy?
Thank you so much
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@Andrew McCulloch
Yes, I agree with the arguments of Hassan as they are fundamentally the bases for policy sciences.
However, I think my interest is in the advancement of the field and the recognition that the structural logic of a policy may have a big impact on the implementation outcomes. Some even suggest that in evaluation one could blame failure more to policy design (noun) than on implementation.
For me, the collaborative approach as suggested by you in concert with mapping as suggested by current research could help objectively or more rigorously analyse the content.
Additionally, for me I think another problem is the "tacit information" or policy elements that we have in policy. They are difficult to trace or rigorously evaluate, and makes policy feedback very difficult. Policy feedback and learning is important to the advancement of policy to include new information to contextualize the policy more to its environment. "Approximating it well against its environment" as suggested by John Peter.
On your starting point suggestion. Yes, that would be a good start. Having identified the data underlying the policy, and relevance (meaning)of the policy. As policy pinching often in 3rd world states tilt toward failure because of the possible mismatch between the policy and its environment. The missing link however, will be the "structural /causal logic"of the policy in Popper's tradition.
That is where my interest to the question comes from, as current scholarship hints at this but doesn't clearly provide methods to evaluate the structural logic.
Thanks,
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We are measuring spectra using Thorlabs OSA which also provides the interferogram signal. We would like to retrieve information about the pulse in the time domain and the pulse coherence.
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Dear Alberto,
the interferogram measured by FTIR-based OSA provides exactly the same information as the usual spectrum. It is impossible to retrieve the pulse shape in time domain using only FTIR interferogram. Very clear and comprehensive discussion of this issue you can find in the book:
R. Trebino, "Frequency-Resolved Optical Gating: The Measurement of Ultrashort Laser Pulses" (Kluwer Academic Publishers 2000).
Particularly relevant chapter of this book you can download from:
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Small Ag precipitate has a coherent interface with Cu, the large one has a semi-coherent interface.
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Thank you!
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I want to find the cross-correlation of the three time series i.e., SST, SSS, and NINO4. Two of those (SST & SSS) have a strong seasonality and the rest one has an interannual cycle. How should I deal with those 3 to find the correlation?
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if you want to measure the interrelation between two signals , it is suggested to use WTC, which is the normalized version of the XWT. Not being normalized, XWT is not altogether a satisfactory method for coherency analysis.
Check out this paper of Maraun and Kurths (2004) on the pitfalls of XWT
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We have conducted an AHP (analytic hierarchy process) to understand experts' opinions of the relative importance of different aspects of natural resource management, specifically for fisheries governance.
From our data, it appears group coherency is low - all our experts have every different opinion about what components of governance are important in the situation we proposed to them.
To confirm this, we want to compute a measure of group coherence as described by Zahir in two papers in 1999. However, this calculation is beyond my statistical abilities. Does anyone have any guide, or ideally code (Python, R script) to calculate this statistic?
Zahir S (1999a). Clusters in a group: Decision making in the vector space formulation of the analytic hierarchy process. European Journal of Operational Research 112: 620-634.
Zahir S (1999b). Geometry of decision making and the vector space formulation of the analytic hierarchy process. European Journal of Operational Research 112: 373-396.
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For this better tool is ANP!
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I have recently begun doctoral research in the field of laser speckle suppression. I want to simulate this effect to provide proof of concept. However, I have no idea where to start. Does anybody have advice on this?
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Dario Ambrosini Thanks for this. However, I am not trying to add speckle to an image. I am trying to simulate the speckle pattern itself (based on the coherence properties of the laser in use). For example, a laser with increased linewidth (due to optical feedback) will have decreased temporal coherence, which directly affects speckle intensity distribution and contrast. The algorithms you mentioned are probably needed (based on statistical copula), however I could not find practical advice on how to actually implement the algorithms. And typically, that is exactly what I need to proceed with simulations!
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When particle size (5um) is greater than the incident wavelength (0.55um) the Mie scattering occurs.The forward scattered light is stronger than the back-scattered light. In literature, it is mentioned that the forward scattered light is exactly in-phase, regardless of separation of dipoles. this is not true for any other direction. The back-scattered light is out of phase.
So, my question is, why forward scattered light is in-phase and back-scattered light is out of phase? If we consider scattering by dipoles, in general the scattering by dipole is coherent. The forward and back-scattered light should be same.
Can anyone explain according to physics (without mathematics) ?
Your cooperation will be highly appreciated. Thanks in advance.
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Basic text books explain mathematically, using the boundary conditions, that light is transmitted through a glass plate without any change in phase at the boundaries. But the reflection from the denser boundary surface to the less dense medium (called external reflection) suffers a Pi phase shift.This is also true for the mechancal oscillation on bound stretched string.
When the surface varies randomly, the reflected or the transmitted wavefront emerges while picking up this random random phase variation. However, the physics of "external reflection" remains the same. The "backward scateering" is "external reflection".
The size of the random surface variations compared to the wavelength determines the detailed quantittative scaterring phenomenon. They could also be isolated particles. But, the basic properties of light transmission and reflection remain the smae.
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I'm trying to check the coherence between a high frequency data and a low frequency data using wavelet.. Is it supported or do I need to convert them to the same nature ..
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I guess Yes, because the Wavelets can be considered as a frequency separation tool...
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There are, of course (correspondingly), "idiotic" Questions. And ridiculous speculations by-analogy (and by-analogy is always suspect). (An example of "Answers" by foundation-less and link-less analogy is " 'quantum' explanations" to several psychological things; it is a bad joke any such person could have a graduate degree !) Sorry: my perception of common things here on RG. And, after years of nonsense, I have decided to state my observation.
It is likely very nearly pointless that I am here on RG (and there have been only so many years I have been able to try to fool myself).
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Questions for the sake of questioning, answers for the sake of answering
I also find that medical issues are being answered by people who have credentials in chemistry, Physics, arts, computer sciences.
Sometimes, the people are discussing matters that are not related the the questions asked and being recommended for such answers.
It could be that most of the medical health care workers are busy in their duties looking after challenging COVID-19 patients and have little time to participate in the discussions on the forum of Researchgate (RG).
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Dear research community.
Can anyone recommend a reasonably priced type of neurofeedback equipment for coherence or ratio training in frontal/midline areas? I am looking for equipment for a pilot-project on children/adolescents and have a very limited budget so want an approach that can give results without needing full LoRETA resolution.
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Please look at the Thought Technology equipment.
Regards,
Rafal
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Let's say I am simulating as simple as BFSK, it has two symbols one entirely on the real plane while other on the complex plane for representing let's say zero and one, that is how the constellation of BFSK looks like. s=data + j*(~data); %Baseband BFSK modulation
Now let's say we added AWGN (N) and Rayleigh fading (h) as well. Rx= h*x + N; Now when I tried to detect it on the receiving side I will have to divide this entire Rx by an h, well that makes sense. My entire graphs for the BER curve match non-coherent detection for FSK. It exactly matched the theory, Eb/N0 vs. BER for BFSK over Rayleigh Channel. Now how to do the same for Non-coherent detection? If I do not divide Rx by h Rx/h, I get a few very very bad results and that doesn't match anything. Theory tells us that In non-coherent detection, prior knowledge of the channel impulse response is not known at the receiver.
In Coherent systems, the receiver needs phase information of the transmitter (the carrier phase) to recover the transmitted data at the receiver side. I haven't used any such thing but still simulation results for BER matched with that of theory for Coherent FSK.
Can someone here help me with this? By not diving by h, will I get better results for Non coherent FSK ? Whether BPSK or BFSK every time we need to divide h*x + N by an h for getting results that match theory.
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"BFSK is done by selecting between two frequencies for each symbol (Binary Frequency Shift Keying). What the OP is showing is samples from M-PSK (Phase Shift Keying); selecting between M phases for each symbol (which would result in two distinct dots on the IQ constellation). Here the two symbols selected are phases 0° and 90°, so these could be 2 of the 4 symbols for QPSK.
To do any form of FSK, the phase must transition over the course of the symbol, given that frequency is by definition the derivative of phase. Thus if one symbol is at a fixed frequency, the phase would vary linearly with time over the duration of that symbol. On an IQ constellation, we would see the phasor rotate at a constant rate from one dot to the next (rotating counter-clockwise to represent a positive frequency and clock-wise to represent a negative frequency).
MSK (Minimum Shift Keying) is the case of the phase rotating ±90° over the symbol duration, as this would be the minimum frequency offset between symbols where the symbols would still be orthogonal. Out of band emissions can be reduced by smoothing the phase from one symbol to the next (generally abrupt transitions in phase or magnitude have high spectral content), which is the intention for GMSK (Gaussian Minimum Shift Keying) where instead of linear phase ramps going up and down according to the symbol used, the phase trajectory is filtered with a Gaussian filter such that the transitions are continuous in the first derivative, meaning the frequency transitions smoothly from one symbol to the next. " Dan Boschen Marcus Müller
Code --
%This program simulates BER of BFSK in AWGN channel%
clear all; close all; clc;
num_bit=100000; %Signal length
max_run=20; %Maximum number of iterations for a single SNR
Eb=1; %Bit energy
SNRdB=0:1:50; %Signal to Noise Ratio (in dB)
SNR=10.^(SNRdB/10);
hand=waitbar(0,'Please Wait....');
for count=1:length(SNR) %Beginning of loop for different SNR
avgError=0;
avgError_awgn=0;
No=Eb/SNR(count); %Calculate noise power from SNR
for run_time=1:max_run %Beginning of loop for different runs
waitbar((((count-1)*max_run)+run_time-1)/(length(SNRdB)*max_run));
Error=0;
Error_awgn=0;
data= round(rand(1,num_bit)); %Generate binary data source
s=data+j*(~data); %Baseband BFSK modulation
NI=sqrt(No/2)*randn(1,num_bit);
NQ=sqrt(No/2)*randn(1,num_bit);
N=NI+j*NQ; %Generate complex AWGN
h = 1/sqrt(2).* (randn(1,num_bit) + j*randn(1,num_bit)); % Rayleigh channel coefficent
Y_with_AWGN = s +N; %Receievd signal with AWGN only
Y=s.*h +N; %Received Signal with both Rayleigh and AWGN
Y= Y./h; %Channel equalization
%---------------------------------------------------------------
%---------------------------------------------------------------
for k=1:num_bit %Decision device taking hard decision and deciding error
Z(k)=real(Y(k))-imag(Y(k)); %Y(k) is actual trasmited signal signal
Z_1(k)=real(Y_with_AWGN(k))-imag(Y_with_AWGN(k));
% if real that mean we chose 1 and if imaginary we chose zero
if ((Z(k)>0 && data(k)==0)||(Z(k)<0 && data(k)==1)) % error conditions
Error_awgn=Error_awgn+1;
end
if ((Z_1(k)>0 && data(k)==0)||(Z_1(k)<0 && data(k)==1)) % error conditions
Error=Error+1;
end
end
Error=Error/num_bit; %Calculate error/bit
avgError=avgError+Error; %Calculate error/bit for different runs
Error_awgn=Error_awgn/num_bit;
avgError_awgn=avgError_awgn+Error_awgn;
end %Termination of loop for different runs
BER_sim(count)=avgError/max_run; %Calculate BER for a particular SNR
BER_sim1(count) =avgError_awgn/max_run;
end %Termination of loop for different SNR
BER_th=(1/2)*erfc(sqrt(SNR/2)); %Calculate analytical BER
close(hand);
semilogy(SNRdB,BER_th,'k'); %Plot BER
hold on
semilogy(SNRdB,BER_sim1,'r--');
hold on
semilogy(SNRdB,BER_sim,'k*');
legend('awgn','Rayleigh');
axis([min(SNRdB) max(SNRdB) 10^(-5) 1]);
grid on;
hold off
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How can we identify the precipitate /matrix relationship (coherent/incoherent) from coffee bean contrast observed in the precipitates.
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Hi Bhavana,
After referring to the attached research article it can be inferred that.
If the precipitates have a coherent strain then they will show a coffee bean contrast in the TEM. Furthermore, in diffraction mode, if the concentric rings are continuous at the interface between the precipitate and the matrix, then it indicates that the precipitates are indeed coherent. Also in this work, in the electron diffraction patterns from (OO1), strong superlattice reflections were observed, which further confirms that the precipitates of A13Sc have an ordered L12 structure. You may refer to the publication for detailed understanding.
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As we face a digital era that connects researchers and researches from around the world there is a tremendous amount of works available for new researchers and their projects and works. Are there any methods, tools, strategies that can improve the bibliographical research stage?
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the internet services data bases are very powerful to obtain any information in the open arena. However, some sites are secure and permission may be obtained from editors and/or those who have published papers there. The academic community is so kind that members may even download some important works and send to you so that your work can be enriched when the publishers permit so.