ResearchGate Q&A lets scientists and researchers exchange questions and answers relating to their research expertise, including areas such as techniques and methodologies.

Browse by research topic to find out what others in your field are discussing.

Browse Topics

  • Sandeep Saini added an answer in Face Recognition:
    Which techniques is better for face recognition of a group of people?

    For recognising the number and faces in a frame, should we with image based recognition or video based recognition approach. Please mention the cons and pros of both the techniques. 

    Sandeep Saini · The LNM Institute of Information Technology

    Dear Aditya, 

    I am not asking about the algorithm used for face recognition. But I thank you for providing a relevant answer. 

  • Rajat Pradhan added an answer in Foundations of Physics:
    Do the effects of mind on matter as demonstrated in the experiments of Radin et al (Physics essays 2012 & 2013) herald a new scientific paradigm ?

    This refers to the recent experiments of Radin et al :

    1) D. Radin, L. Michel, K. Galdamez, P. Wendland, R Rickenbach and A. Delorme
    Physics Essays, 25, 2, 157 (2012).
    2)  D. Radin, L. Michel, J. Johnston and A. Delorme, Physics Essays, 26, 4, 553 (2013).

    These experiments show that observers can affect the outcome of a double slit experiments as evidenced by a definite change in the interference pattern.

    It requires urgent attention from the scientific community, especially Physicists.

    If these observed effects are real, then we must have a scientific theory that can account for them.

    Rajat Pradhan · Utkal University

    I have always been an admirer of Charles Francis for his very frank expressions and deep understanding of issues at hand, and my admiration grows day by day. He has put it very clearly that the uneasiness we feel at such an experiment is precisely because we don't have a reasonable theory for such things that involve consciousness.

    Thus to call it pseudoscience is just to give it a bad name. It does not serve any worthwhile purpose. We have to be serious about it.

    We know that mind affects matter and vice versa and we know that we don't have a theory for such interactions. So it now depends on whether we restrict physics only to the domains so far investigated or we extend it beyond.

    As far as the experiment is concerned it is a double slit experiment and if the proposed effects are really there, then for being able to perform ordinary double slit experiments properly in the physical sense we must study this aspect also in physics, since it (mind) may be a potential source of disturbance of the pattern that we are trying to generate for the study of physics itself and we must eliminate all such extraneous sources of disturbance (like the nearby minds) in order to make even a physically acceptable study of the pattern in relation to measurement of wave-length or fringe width etc.

    I have invited Radin himself to join the discussion and if he does he may clarify issues himself firsthand.

  • Charles-Francois Vincent Latchoumane added an answer in Seizures:
    What is the surgical methods that we can done to control seizure ?

    3 years old child with uncontrolled seizure but he has spastic tetraplegia because of CP , he has also nail hypoplasia? what do you think doctors

    Charles-Francois Vincent Latchoumane · Institute for Basic Science

    Despite all the information you provided, I don't think anyone here would be able to make an educated guess without further test on your patient, including EEG recording too locate a possible focus for the seizure and its type and response to medication (list available here: http://www.webmd.com/epilepsy/medications-treat-seizures).

    Nail hypoplasia might also be a results of medications (anti convulsant), here again the history of the patient is needed. I just hope you are not planning to do the surgery yourself.

  • Naoufel Boulila added an answer in Requirements Engineering:
    How can we validate a research in Requirements Engineering?

    Actually I am working in Security Testing, so how to get some data set for validation. The data set that I require must contain the threats/attack with their frequency and point of attack for a particular organization/website.   

    Naoufel Boulila · Siemens AG

    as Anurag mentioned, if you just need a research method, then empirical studies would help here. you can start by:

    1. defining a hypothesis,
    2. set up an experiment (controlled or not), 
    3. observe,
    4. collect data,
    5. analyze,
    6. derive result,
    7. adjust the hypothesis
    8. if needed, repeat experiment with different population as many times as needed,
    9. then confirm or not the hypothesis
    10. then derive a law.

    but if you just need specific data to validate a process, a method, or case study, you can use simulation methods with support of tools like Simulink/Matlab etc.

    good luck

  • Ahmed A. El Tayyan asked a question in Electricity:
    What shall you do if you suffer from not having electrical power at your city?

    It is a crazy World and every thing could happen at any time and at any place. How do you imagine your life if there is no electricity at your city.

  • Saedah Abd. Ghani added an answer in Clinical Supervision:
    Which clinical supervision (group, external, 1-2-1, peer etc) and which ratio to case load is effective in teams for PD/high risk patients?

    We are community based young peoples service for emotional dys-regulation and personality disorder. We are reviewing our systems and procedures including our supervision framework for effectiveness.

    I am looking for similar intensity services managing high risk patients to investigate best practice clinical supervision frameworks. 

    Saedah Abd. Ghani · USIM | Universiti Sains Islam Malaysia


  • Rahul Ramekar added an answer in Popgene:
    How do I make input file for POPGENE software in case of co-dominant markers for genetic diversity analysis?

    How do I make input file for POPGENE software in case of co-dominant markers for genetic diversity analysis?

    Rahul Ramekar · Kangwon National University

    You can also use GenAlEx, where you can export your input file in format for popgene analysis. 

  • Carlos Jimenez-Martinez added an answer in Sustainability Research:
    What are the most sustainable waterfront regeneration projects in the UK, US, Australia and Canada?

    I am preparing an international comparative study on the impact of planning policy instruments on the behaviour of private sector stakeholders in the sustainable development of urban waterfront locations.

    Carlos Jimenez-Martinez · Universidad de La Laguna

    Hello. Some of the professors from this Master in Waterscapes could answer your questions: http://waterscape.aaamaster.it/ (look for "Université Laval", Canada. Good luck)

  • Song Chen added an answer in LDPC:
    Why are the parity bits of generator matrix of QC-LDPC decimal number?

    I creat the generator matrix using the method in paper "Efficient encoding of quasi-cyclic low-density parity-check codes". The parity bits of the generator matrix are decimal number. Why are the parity bits parts in the generator matrix not 0 or 1?

    I focused on the LLR computation of the codeword for soft-decision LDPC decoidng. The decimal number are difficult to get LLR information in noise channel.

    Using the EG(3,2^2) in GF(2^6), I create type-I QC-LDPC parity matrix H=[H1,H2,H3,H4,H5] with five parallel line pounds. 

    Song Chen · University of Science and Technology of China

    We used  the matrices  in the WiMAX and Wi-Fi standards, which generate QC-LDPC codes.

  • Fabrizio Nunnari added an answer in Genetic Algorithm:
    Is there any best practice to check the convergence of a genetic algorithm even when the fitness value of the individuals changes across generations?

    I'm using a genetic algorithm to solve a search problem.

    Within a generation, I calculate the fitness value of the individuals by comparing the individuals with each other (Pairwise Comparison). As usual, individuals with the higher fitness value are elected to migrate to the new generation.

    However, in the new generation, the comparison of the elected individuals with the new ones will yield to different fitness values. Let's say that the fitness function is relative within a generation, hence not comparable across generations. (Indeed, the fitness value is always normalised in the range [0,1])

    This makes it hard to check if the evolution is bringing to better population.

    Is there a methodology, or best practice, to check for the convergence genetic algorithm where the fitness function is valid relatively only within a single generation?

    Fabrizio Nunnari · Deutsches Forschungszentrum für Künstliche Intelligenz

    First of all, thanks everybody for the great answers.

    Let me clarify two points that I should have mentioned in the description. (I will update it accordingly)

    First, the approach that I am taking is a case of Interactive Genetic Algorithm. It means that the fitness value is determined by people voting/scoring/comparing items. There is not really an objective function. The objective is to increase the level of appreciation/agreement among people.

    Second, the fitness value within each generation is normalised between 0-1. Plus, the whole 0-1 range is used. Meaning that in each generation there will be the best individual with fitness value at 1 and the worst individual with fitness value at 0.

    Now, I thought of checking the convergence using the following strategy.

    I assume that, if the specie is improving from a generation to the next, the elected individuals are surpassed by ones with better rank.

    In generation n (containing N individuals), I will sort all the individuals from the best (i=1 <-> fit=1) to the worst (i=N <-> fit=0), where i is the ranking position. The k best individuals will be elected to pass to generation n+1. After collecting users votes, I will sort also the individuals of the generation n+1. Now, I would compare the k individuals which migrated from generation n to generation n+1. Their fitness value will be completely different between the two generations, hence incomparable. However, if the elected individuals are "surpassed" by better individuals, their fitness value should decrease, as well as their rank position after sorting. By checking the average of the difference of the fitness value (or rank position) I should deduce if the specie is improving.

    Sounds it good?

  • Brian P. J. Stevens added an answer in Lamins:
    Probable Laminated Claystone, yet stumped on origin. Any Ideas?

    This rock was found in NYC. It may have traveled on/in the ice sheet from as far north as Labrador, or it could have come from more locally. There appears to be some limonite. This rock may have come from dredged up European or other ship's ballast rock, out of NY waterways. Please help me with any ideas you may have. I will try to post a few more photos. Thanks!

    Brian P. J. Stevens

    Would a thin section help Are there any textures that could indicate volcanic ash?

  • Subbaiah Tondepu added an answer in Nitric Acid:
    Is there any procedure for the reduction of Nitric Acid (HNO3) to Nitric Oxide (NO) using copper as catalyst?

    I was planning to synthesize a complex with NO as ligand, but it is difficult here in the Philippines to order NO gas, so I had to synthesize NO gas from simple precursors. I have read that reduction of NItric Acid (HNO3) to Nitric Oxide (NO) is feasible using Copper (Cu) as catalyst. can someone tell me what is the exact procedure for the reduction process. I know its a bit dangerous as to dealing with NO gases because it can lead to death when exposed in large amounts.

    I hope you can help me guys. :)

    Subbaiah Tondepu · Koneru Lakshmaiah University

    We have reduced nitric acid using electrochemical technique from 4 M to 1M.Using chemical reduction also,nitric acid can be reduced

  • Omer Nevo asked a question in Tropical:
    An easy method to measure ethanol content in fruits?

    I would like to measure ethanol levels in tropical fruits in the field. Is anybody familiar with a cheap and reliable method?

  • Lutz von Wangenheim added an answer in Analog Electronics:
    Is a transistor really an amplifying element? Is it an active or passive device? Are there amplifying elements? Is it possible to amplify energy at all?
    Is it well known that the transistor is an active element used to build amplifiers. But IMHO this is not true. The transistor is not active but passive element; the only thing that a transistor can do is to dissipate energy. So, it is not amplifying but attenuating element. It is just a resistor (non-linear, electrically controlled but still a resistor) that decreases the current.

    The true amplification is impossible; so there are no real amplifiers. The so-called "amplification" is just an illusion, a clever trick and the "amplifier" is just a "magic box" where we see a bigger output power but this is not the amplified small input power. This is else's power.

    In analog electronics, we implement such an "amplification" in the possibly most paradoxical, absurd and silly way - to obtain output power bigger than the input one, we get a big power source and then throw away a part of it (from zero up to the whole power). In comparison, in energetics, they can't afford to do it..
    Am I right?
    Lutz von Wangenheim · Hochschule Bremen

    I think, we all know that the terminology in electronics never is "correct". Can  a current flow? No.  Is any circuit really linear? No. Can a wave be really sinusoidal ? No. Does a current source really provide a current (independent on the load)? No. Is an amplifier stage with RE signal feedback still a common-emitter stage? No.

    The most important   thing is to use terms which can avoid misinterpretations and misunderstandings.  Therefore, I support the view that we have an amplifier - if it is powered or not.

  • Chris Pirson added an answer in Dendritic Cells:
    Can monocyte derived DCs produce M-CSF or GM-CSF?

    Hi there,

    MCSF can be produced by variety of cells and I was wondering if anyone know whether M-CSF (and GM-CSF) can be produced by monocyte derived dendritic cells?

    Chris Pirson · University of Surrey

     Hi Elwira

    I tried to look at this during my PhD but I couldn't get a straight answer.  I tried to measure GM-CSF by ELISA in the supernatants but because the cells were cultured in GM-CSF it was hard to tell.  I tried to control for it but could never get a particularly clear answer.

    The best information that I could find was that you wouldn't expect MDDC to produce either M-CSF or GM-CSF but I wasn't able to confirm this.  Perhaps your best option would be to look for transcriptome evidence of expression of these molecules (assuming you use GM-CSF in your MDDC culture).

  • Jules Lloyd Hammond added an answer in Photolithography:
    How do we calculate exposure in photolithography?

    We are using Karl Suss MA6/BA6 and the lamp power shows 350 W and we do exposure for 10 sec. i am confused how to find power per unit area? which area to consider - mask or source area??? kindly help

    Jules Lloyd Hammond · University of Bath

    As Jose rightly points out, you need to measure the UV intensity (MW/cm^2) so that you can calculate the required exposure time.

    We currently use a 'Karl Suss UV Intensity Meter-Model 1000' with the 'P365nm probe'. Often the UV lamp in the mask aligner will require a warm up period (ours takes around 30 minutes to stabilise).

    When taking measurements you'll probably find there is a slight difference in intensity between the centre and the perimeter of the chuck and this is worth noting in case you need to use the perimeter.

  • Gaurav Magare added an answer in Perl:
    Any suggestions in extracting a sub sequence from a large text file?

    I have a large text file. How can i extract text between specific text pattern and print it to another file..is there any script for it in perl or python

    Gaurav Magare · Citrix Systems

    This depends on how large of a file are we talking here. If this is a small file, look at any regular expression solution. grep, awk, any-programming-language with regex support should work. But if the file is massive and response time is critical, you might have to dirty your hands with something like Hadoop.

  • Rajamanickam N asked a question in Multiferroics:
    Which is the best material for multiferroic research?

    Other than that BiFeO3.

  • Steffen Hau added an answer in Micromachining:
    Is possible to do micromachining on micro chips?

    The chip which is used in mostly in laptop's and CPU's, under the cover of processor. is possible to do micro machining process on that chip.

    Steffen Hau · Universität des Saarlandes

    @ Sameer: Unfortunatelly I don't get what you mean with "chips are covered with wafer on tap portion".

    You can do micromachining on a chip (Silicon with active areas) . You just need to take care that no active area is effected, neither by chipping or crack formation. Which means you need to have a enough space. The sawing process for chip singulation is actually a kind of chip machining.

  • Aniruddha Mitra added an answer in Animal Behavior:
    Can one infer a dominance hierarchy from an undirected, weighted social network?

    I have association data from 12 geographically separate populations of wild birds and I am interested in trying to use that association data to build a dominance hierarchy for each population. Specifically, we are using Radiofrequency Identification (RFID) to gather information on individual associations. At one of our sites, we supplemented the RFID dataset with observed directed interactions between birds using videography, which we then used to construct a hierarchy using the methodology of Shizuka and McDonald (2012) [Animal Behavior]. Because videography and direct observations are extremely time intensive, we would like to know if there is a way to use the RFID data (undirected, association only) to infer dominance hierarchies at the remaining 11 sites.

    So far, the only paper I can find that does this is "Inferring the Maximum Likelihood Hierarchy in Social Networks" by Maiya and Berger-Wolf (2009). Their methodology seems reasonable to me but can anyone speak to the validity of their approach, and/or know of others that I might use?

    Thanks in advance! 

    Aniruddha Mitra · French National Centre for Scientific Research

    How will you conclude anything about dominance interactions unless you have behavioral observation data about dominant-subordinate interactions? From what you have written, you will only get something like an association index from the RFID data, you will just get an idea about how much time any 2 given birds spend with each other (or in the vicinity of each other). Time spent together can be in a lot of other behaviors, other than dominance interactions. Depending on the ecology of the species you will have either pair bonds or group foraging and it will be impossible to tell about dominance just from association frequency. Try looking at the data set you have where you have both RFID and behavioral observations to see if there is any patterns. But even if there is, it will be difficult and maybe even erroneous to extrapolate from just one population to 11 other populations.

  • Mark Johann King added an answer in Traffic Engineering:
    Any researcher interested in working with transportation regulations and their impacts in megacities regarding developing countries?

    Economic growth in metropolitan urban areas in developing countries is resulting in increasing demands from companies for goods and services. In fact, Governmental regulations aim decreasing mainly traffic congestion, although many others problems have emerged. Are these regulations enough? Which regulations are the most relevant/necessary in freight distribution system?

    Mark Johann King · Queensland University of Technology

    Hi José

    I have an interest primarily in road safety issues in developing countries, which doesn't necessarily fit with your need, however I wanted to make a point which applies equally to freight distribution regulation as to traffic safety regulation.  That is: the effectiveness of regulation depends very much on the effectiveness of enforcement, and this in turn is linked to governance issues like corruption,  Having sound regulations but lax or corrupt enforcement is not much better than having no regulations at all.

    Regards Mark mark.king@qut.edu.au

  • Niklas Zimmer added an answer in Photography:
    Is there a kind of fundamental difference between continuous light source and high speed flash photography?

    We have built a kind of light source that can produce both continuous and pulsed (500 ns) light. When we tested with the continuous mode (dark room and target was a glass of water and dirt) the target was beginning to shine but in pulsed mode the only thing that we could capture was just a thin arc around that glass (the mixture of water and dirt was completely dark and unseen). But why? In my theory there is not any difference between pulsed and continuous light just in making blurred image or sharp image of a moving object!

    Niklas Zimmer · University of Cape Town

    usually you will find that flash units output a lot more light than continuous lighting. This topic is exhaustively covered in the tutorials on large vendors' websites such as B&H. It sounds as if the pulsing of your unit is doing the opposite, though: draining or chopping up the source power. There is a lot of hybrid flash/continuous lighting on the market now since the advent of LEDs as well as the rise in cross-over video/stills SLRs and mirrorless cameras. Of course, precise synching is one of the key issues here, as stated correctly in the previous comment.

  • Tomofumi Miyashita asked a question in Journal Impact Factor:
    How to measure leakage currents using doped Ceria electrolytes in SOFCs?

    In SOFCs, using YSZ electrolytes, the open circuit voltage is 1.15 V.

    But using doped Ceria electrolytes, the open circuit voltage is only 0.80 V.

    They said that there should be not only RI-drop, but also polarization voltage losses.

    However, every electrode degrades with time.

    Consequently, the open circuit voltage should become lower with time due to electrode degradations, since the polarization voltage losses should become larger.

    But experimentally, the changing in the open circuit voltage has never been reported.


    Necessity of verification of leakage currents using Sm doped Ceria electrolytes in SOFCs

    Journal of Materials Science (Impact Factor: 2.31). 01/2006; 41:3183. DOI: 10.1007/s10853-006-6371-8


  • Bhoj R Singh added an answer in Microbial Genetics:
    What are the good microbial genetic targets to study the microbiome of lower respiratory track in asthmatic subjects?

    I would like to identify the difference of microbiome in asthmatic and non asthmatic subjects. Which available technique is most efficient for this study. 

    Bhoj R Singh · Indian Veterinary Research Institute

    16s rRNA gene followed by NGS are for bacterial community, you have to think of several viruses, noxious chemicals and other pathopotential molecules. Microbiome, a small word is very complex in doing and even more in understanding in lack of proper control. Therefore, caution sign(s) needs to be read at every stage.

  • Gandhidas Sonajirao Lavekar added an answer in Herbal:
    Is there an antidote for herbal medication drug interaction in the perioperative setting?

    In regards to the implication of herbal medication in the OR, there different herbal medications and its drug interaction. Are there any medications you can give to reverse any of the interactions/effects? (for example, if you give a narcotic you can use Narcan to reverse its effects), are there any drugs that can do this for herbal medications? Thank you.

    Gandhidas Sonajirao Lavekar · Central Council for Research in Ayurveda & Siddha

    Yes, there are many herbal drugs given as antidote in case of drug drug interaction, depends on sign and symptoms.  Antagonist drugs are there, in Ayurveda in many compound formulations are of antagonist, synergistic, bio-enhancer etc.

  • Eleonora Accorsi added an answer in Environmental Geophysics:
    Is there a study or a list of all the social vulnerability index to a natural hazard?

    I have to measure the tsunami's social vulnerability of an italian city and I'm searching for all the index that I can use to do that. I've found a lot of articles but no one updated to recent years (2013-2014). Thank you!

    Eleonora Accorsi · University of Bologna

    Thanks for the very interesting article Mr Bothun, reading those bulletins is very impressive!

  • Shabir Ahmad asked a question in Melanins:
    Anybody having experience in chemical analysis of melanin especially pyomelanin?

    We have some interesting mutants which is producing a high amount of black melanin like pigment when grown in minimal media having tyrosine, we speculate that it may be pyomelanin, and interested to find out its chemical nature. If somebody have experience in melanin chemical analysis kindly help me...

  • Giulio Caravagna added an answer in Stochastic Models:
    How do I handle time dependent parameters in disease transmission using stochastic models?

    I am using a birth and death process. 

    Giulio Caravagna · Università degli Studi di Milano-Bicocca

    See answer to another question.

  • Dario Fassini added an answer in Biomaterial Science:
    How can I apply a thin, even layer of liquid glue to a small piece of a material without it overflowing when I press down to adhere it to glass?

    I am trying to apply a thin layer of a liquid glue to a small piece of a biopolymer (5 mm2) which I am then adhering to glass. I am attempting to do this without a dispenser machine due to the high cost. Generally I am finding it okay, but there is often leakage of the glue which leaves a messy result and also compromises the biopolymer. Any help with regards to this would be much appreciated.

    Dario Fassini · University of Minho

    Hi Catriona,

    for collagen films (CFs) what I use to do is to apply the cianoacrilic cement directly on the CFs and then remove the glue in excess by dragging it gently on a standard A4 paper. You have "just" to take care of not applying any pressure between the biomaterial and the paper. Once the glue excess has been removed (in the case of cianoacrilic cement) you have to place the material in position carefully since it will adhere very fast and you will not have a second chance to adjust the position...

    Good luck!