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.
- How can I trasmit and receive data from FPGA (ML 506) board using serial cable/hyper terminal?
I want to execute the encryption algorithm on ML 506 board.So how can I give inputs to board and how can I receive the output from the board. In some papers they mentioned it is possible using HYPER TERMINAL. Can anyone know this?
If your purpose is to conect your crypto setup so you can automate your analisys, It is not something you will find a ready-made solution. First, as Bhoopal has said, it is important to know if you need to read some information that can not be made available as an input or output of the FPGA. For instance, if you are willing to make a DPA attack some way to receive power data must be available. In this case the problema is very different and you will need a special board with external circuitry to read this data. Assuming you only want to feed plain text to your circuit and get teh encripted data out you will have to make two things: 1) First you have to design a block (using some HDL of your preference) that will receive octets and assemble the input word of your crypto block (for instance 64bits, 128bits, etc, depending on your algorithm). The same will have to be made for your outputs: a block will take the words and serialize then ingroups of eigth bits (octets). Since this "connection block" will interface to your design it must be custom made by you. 2) You must include a UART that will take each octet and transmit serially, and also will receive serially and convet data to octets. Fortunatelly a UART is a ready made block and you will find many in the opencores as Maryam said. You can use a very simple one (i believe there is one called tinyUART that works well). Usually to send data your "connection block" will provide one octet, sinalize some send input of the uart and wait untill the octet is send (there is always a UART pin that will sinalize when ready somehow). After that it will send the next octet and so on. To receive data the UART will indicate that a octet has arrived and your "connection block" will read the octet from another set of pins. If you choose a simple UART and keep your communication protocol simple the "connection block" is a relativelly small state machine and a few registers. It does, however recquires some experience with HDL and FPGA. If you choose a SOC FPGA with internal microprocessor core there is an alternative: you can map your cryptographic block inputs and outputs to memory and use the development tools of the system to access the internal memory. There are different procedures to to this in each manufacturer tool and it usually requires the inclusion of some sort of predefined IP core in the system assembly tool (f.i. Qsys in Altera) .Following
- How to find cloud service repositories?
Repositories which store cloud services with the corresponding provider specificationFollowing
- Can the proposal about the electromagnetic nature of all interactions in living organisms add anything new to our understanding of their functioning?
The authors look for possible perspectives of such an introduction. But on my oppinion, A) it's obviously that any forces in the alive media (except gravitation) have electromagnetic nature; B) such a detalization is justified only for the problems of field-particle interaction, like Quantum chemistry, Moleculare dynamics, Radiation impacts and so on. To spread EMF-problems over diseases, organs or cells one needs to have related observable effects.
Dear Яков Рейзенкинд,
I think it's just misunderstanding. I ment that any forces (except gravitational and nuclea and week) may be reduce to electromagnetic one. The exchange interaction in Ouantum physics is a hidden fenomena which appears due to an approximate reduction of the many particle problem to a set of quasi-particle equations. This is not an observable force, I think.
- Why is the threshold of Point biserial correlation (item discrimination) in item analysis 0.2?
Point biserial correlation is used to to determine the discrimination index of items in a test. It correlates the dichotomous response on a specific item with the total score in a test. According to the literature items with Point biserial correlation above 0.2 are accepted. According to Crocker (Introduction to classical and modern test theory, p.234) the threshold for point biserial correlation is 2 standard errors above 0.00 , and the standard error could be determined by (1/sqrt(N)) where N is the sample size. What is not clear to me is that in tests we need items that have high discrimination (Correlation) and if Point biserial correlation is a special case of pearson correlation that means that by accepting 0.2 as a threshold we are accepting the fact that the coefficient of determination is 0.04 and total score is only capturing 4% of item variance.
Yeah, this was just and easy, semi-arbitrary rule of thumb. Some types of assessments will have higher point-biserials than other types of assessments, and you can be flexible with what you consider to be minimally acceptable. The range of ability in the pilot sample affects Rpbis, as does difficulty of the item (substantial floor and ceiling effects).Following
- SPSS for multiple imputation to have a dataset with no missing values
I have a dataset with some missing values. I used SPSS for multiple imputation to have a dataset with no missing values (for AMOS). How should I save and use the pooled outcome in AMOS?
Let's go back to the original question. Reza wrote (with emphasis added):
- I used SPSS for multiple imputation to have a dataset with no missing values (for AMOS). How should I save and use the pooled outcome in AMOS?
As far as I can see, we don't know the answers to these important questions:
- What type of analysis did you perform with SPSS? (This will determine what the "pooled outcome" you refer to consists of. E.g., if you were estimating some kind of regression model, the outcome will be a table of pooled estimates of the regression coefficients.)
- What did you hope to do with the "pooled outcome" in AMOS?
In a later post, Reza wrote this:
- However, results are only usable inside SPSS and you cannot export the outcome to any other package because SPSS performs analysis based on 5 imputed versions and then creates a pooled answer for the analysis (not a pooled dataset).
And then Pat wrote:
- Ah, if SPSS can only export a single dataset, that was probably the source of my confusion!
I'd like to clarify that regardless of what software one is using, multiple imputation is never about generating one "pooled" data set. It is about generating multiple imputed data sets, performing the desired analysis on each of those data sets, and then generating pooled estimates of the results (e.g., regression coefficients & their associated SEs). So this is not some limitation of SPSS--it would apply equally to any other package.
Second, the 5 (or however many) imputed data sets generated by the MULTIPLE IMPUTATION procedure in SPSS are all in the same data file. There is a variable called Imputation_ that is equal to 0 for the original data set, and to 1 through m for the m imputed data sets. (When you perform the actual analysis, the file is SPLIT BY Imputation_. This is what tells SPSS go generate the pooled estimates.) So if you are trying to use those multiple imputed data sets in AMOS, I don't see what the problem is.
Finally, for the sake of those who do not use SPSS (and those who do, but don't bother to read the documentation), a list of SPSS procedures that support computation of pooled estimates from multiple imputed data sets can be viewed at the first link below--click on Procedures That Support Pooling.
p.s. - For questions about how to do things with SPSS (and other related products such as AMOS), I would recommend posting to the SPSSX-L mailing list (second link below) rather than to RG. Actual SPSS users participate in that forum, so you might have better luck getting answers to your questions. ;-)Following
- What treatment would you suggest for a patient with chronic, severe and scarring hidradenitis suppurativa?
As you are probably aware hidradenitis suppurativa is a chronic pyogenic and scarring condition involving apocrine glands in the axillary, perineal and genital areas of the body. The aetiology is shrouded in mystery. However the pathophysiology involves an unexplained keratinous plugging of the ducts of the apocrine glands. This leads to dilatation and rupture of the glands with intense inflammation in the surrounding tissues.
The lesions may subsequently become infected with a variety of Gram positive and Gram negative microorganisms including Staphylococcus aureus, non-haemolytic streptococci, E. coli, Proteus species, Pseudomonas aeruginosa, and Bacteroides fragilis.
Chronic extensive disease could be extremely distressing to the patient. In advanced disease there is often poor response to antibiotic therapy (including tetracycline, ciprofloxacin and clindamycin) and surgical intervention may become necessary followed by skin grafting.
I would welcome your thoughts on the management of a patient with chronic and extensive ciccatricial disease. Many thanks in anticipation for your suggestions.
Sayed S Bukhari MD FRCPath
Consultant in Infection
I would suggest, although it sounds somewhat impudent, that a reading of the recent review in Best Practices will bring several areas up to date for you. See the Open Access article at http://www.bestpracticeobgyn.com/article/S1521-6934%2814%2900136-9/abstract
Also, if you have UpToDate.com available, take a look at that as well.Following
- Can anyone recommend a good, inexpensive trail camera that can record predation events on snakes at a gestation site?
We will be placing foam models out at potential gestation sites to measure predation intensity. Trail Cameras could help us identify what species are doing the actual predation.
As others have pointed out, your first concerns should be identifying a camera with the appropriate features for your objectives and the species you expect at your sites--things like wake-up or trigger time, video or not, and stealth, IR or full color (white-flash) options. Regardless, I would be very wary of spending a great deal of money on a large number of inexpensive camera traps if you're using them for research and hope they'll last longer than a season. Many of the less expensive brands/models are spotty at actually detecting animals, so if having high confidence in your detections (or especially non-detections) is a priority, I would spend more $$. Also, while buying cheaper cameras may seem more cost-effective, if they start having problems after a season or two you'll spend much more money, time, and frustration constantly sending them back to the maker or having to replace them. If you're only buying a relatively few cameras, and hope to use them for years to come, I wouldn't buy anything but Reconyx. If you need to buy many, and it's not critical that they all perform optimally, and you only need them for a season or two, you might be satisfied with less-expensive brands and models.Following
- Any examples of cultural connotations rather than color terms?
I need examples that show differences of connotation from one culture to another.Following
- Can you help me with the transfer of proteins from SDS gel to nitrocellulose membrane?
My protein of interest is very small (9-11 kDa). I use a 20% acrylamide gel to run my proteins and use a Bio-rad high intensity field 1 hr (350mA) wet transfer. I do not use SDS on my transfer buffer as my protein of interest is small. I stain my gel with coomassie after transfer and noticed most of the proteins are left on the gel. Has anyone looked at lower MW proteins? Suggestions please?
1. Transfer is never 100 % complete, so you will always get staining of protein bands in your gel after transfer. Have you actually checked (e.g. by Ponceau stain of your membrane) whether there was protein transfer?
2. For small proteins, I recommend Tricine SDS PAGE (see link)Following
- Any easiest and safer method for O-Acylation of Phenols with 2-bromopropionyl bromide?
Hi all, I am working on O-Acylation of Phenols with 2-bromopropionyl bromide, but unfortunately I am not getting the reaction completion confirmation through TLC monitoring even after following several references involving ZnO, CoCl2, acid catalysis, and base catalysis reactions.
Could anyone kindly help me with exact procedure with reaction conditions of Phenols with 2-bromopropionyl bromide.
Thank you Dr. Kirill I. Petko:
Thanks a lot for the detailed process, I agree with you regarding the usage of Pyridine, so I tried using Na2CO3, K2CO3, NaHCO3 too, but somewhere somehow, I am not getting TLC confirmation.
The next time I will follow the method that you have suggested, could you kindly let me know the above said procedure's reference, which would be helpful for me.
Thanks once again for letting me to know the detailed procedure.Following
- Full sequencing of 16S rRNA gene?
I am trying to get full sequence of 16S rRNA gene from actinomycete isolates. I have tried 8F and 1492R set prime but I have got 1384 bps and is still lower than about 1490 bps. I was wondering if anyone could tell me what is the best approach to reach to the full sequence of the gene?Following
- Can anyone provide help using software for item response theory?
There is software available for item response theory, but it is very hard for me to understand how they work. Can anyone provide information on this.
I totally agree with Cristiano and Alan. IRTPRO and Xcalibre are much easier to use because of the UI rather than command code. You can see more on Xcalibre at https://www.youtube.com/user/ASCpsychometrics.
(Disclosure: I am the author of Xcalibre. But I also highly recommend IRTPRO.)Following
- Does anyone know of research looking at self-regulated learning in MOOCs?
Currently writing the literature review to underpin our own work in the field (see link) and want to make sure I havent missed anything.
One of the few research articles that talk about learning in a MOOC: http://www.irrodl.org/index.php/irrodl/article/view/1902Following
- What papers should I read about Distributed Denial of Service Detection, Prevention technique ?
I am starting researching deeply about DDOS and detection algorithm as well as preventing technique. Detect and Prevent DDOS both for Streaming Media Application and Web-based Service. What should read latest science paper about this field?
I read this
1.Edhud Doron , WDA: A Web farm Distributed Denial Of Service attack attenuator
2.Huizhong Sun, Huizhong Sun ; Chao, H.J. ; Wing Cheong Lau, Wing Cheong Lau ,ALPi: A DDoS Defense System for High-Speed Networks, Ayres, P.E. ;
3. Chen Lei, Chen Lei ; Ye Dejian, Ye Dejian, DoS and DDoS Attack's Possibility Verification on Streaming Media Application , 2008 International Symposium on Information Science and Engineering, Dec. 2008, Vol.2, pp.63-67
also, try this one:
An efficient and easily deployable method for dealing with DoS in SIP services, Computer Communications, Vol. 57, pp. 50-63, 2015, Elsevier.Following
- Anyone familiar with XPS Carbon nanotubes?
I fitted XPS for CNTs and it was more than 12 peaks using CasaXPS program,
but all the former papers fitted CNTs only 6 peaks. I do not know now if my fitted is wrong or CasaXPS not a good program to use in that fitting?
Firstly, Thank you very much.
Secondly, yes I am trying to fit the C1s spectrum. I already attach an image. it is for CNT oxidized with HNO3.Following
- Type-I and type-II error and alpha value relationship in research?
What is relationship between type-I and type -II error and how these correspond to alpha value?
I would suggest using SAS, R, or even something like Excel and using the random number generators to create populations that you can then sample. You can draw the sample directly from a random function or you can create a population using a random function and then withdraw samples. The latter approach more accurately simulates practice because you have a "population" that is from an underlying distribution of possible values and from which we take a sample. However, dispensing with that complexity will help simplify initial efforts.
Because this is done with a computer, you can withdraw samples many times. So I will have 100,000 trials where I gather 5 samples from each of two populations. I will then do this over using 50 samples, then 500 samples, and 5000 samples. I will have a random normal distribution with mean X and standard deviation Y and another population with mean X+1 and standard deviation Y. I then know that the true difference between the populations is 1, and I can record the outcome of my t-test (or whatever I hope to use on the real data). I can then add other constants, and I can change Y and determine exactly the limits of my method. Since I know which observations are from each population I can also calculate Type 1 and Type II error rates and see how these change. This is an easy programming exercise (though it will take time), but assumes that you know programming. The game here is using the computer to create a population where you know what the answer will be. Then sampling that population to see how the act of sampling and the method interact to distort your perception of "truth."Following
- What are the different datasets available for network intrusion detection?
What are the different datasets available for network intrusion detection in publucdomain except KDD CUP 99 data set?
Try this one:
- What are the differences between Targetlynx and Quanlynx?
Hi guys, I am bit confused again by the masslynx application managers:
what are the differences between Targetlynx and Quanlynx? it seems both of them can do quantification.
Yes, both programs are application managers for quantitation purposes.
TargetLynx is an evolution of Quanlynx. Both are working at the same way, but TargetLynx is able to add some other capabilities.
Differences: TargetLynx offers:
1) More than 1 Ion ratio.
2) Trendplot: Is having an extra tool to create control and statistical charts.
3) QCMonitor: You can control the quality control samples, taking decissions and managing your sample lists.
4) Quanpedia: Collection of methods with MRM for several compounds or even complete methods to analyze contaminants in food and environment.
I hope this can help you,
- Does the prostate cancer cell line MDA-PCA 2b express CXCR1/2?
I've been treating my MDA PCa-2b cells with a component that is known for creating apoptosis, but more interestingly this component is decreasing the expression of intracellular protein beta-arrestin 2, at this time we are trying to figure out the pathway behind it. I am currently looking at ERK; I've been treating my cells (that are already treated with the component) with Interluekin 8 (at difference concentrations) to see the affect of ERK, however I am not seeing much of a difference in the expression for ERK for both my treated cells and control cells. I'm trying to determine why I am not seeing a difference in ERK expression (especially in control cells) when treated with IL-8, possibly MDA-Pca 2b does not express in the CXCR1 and CXCR2 that is associated with IL-8. Any thoughts?
Thank you! I will look more into this.Following
- What is the fine difference between a business plan, feasibility studies and a marketing plan?
Three terms used interminably in business need to know the scientific difference ,,
what about business acumen?
or PROJECT BUSINESS PLAN (PBP) or (CHARTER) - The agreed contract between the Client and the Project Management Team.Following
- Are item means typically different in Xcalibre?
I am running an IRT analysis on an instrument in XCalibre, and the analysis reports substantially different means for the items than those calculated in Excel? Is there some weighting happening of which I am unaware?
As Alan suggested, there is indeed likely an algorithmic reason that Xcalibre might be calculating differently. I know of one situation for sure. A few weeks ago I received a support email with the same question, and the issue was that they were running a 5-point polytomous calibration on a sample of only 36. (!!!!) Xcalibre automatically combines response levels with N=0. In that case, there was, for example, an item where no one responded as 1 or 2, only 3-4-5. The 1 and 2 levels were dropped and it was treated as a 3-option item, and since numbering starts at 0 or 1 (depending on if doing PCM or RSM approach), it gets renumbered. So the researcher anticipated an item mean of 4 or so and it was reported as 2 or so.
I'd encourage you to contact the support team about the issue.
(Disclosure: I am the author of Xcalibre.)Following
- What is the best Stat3 inhibitor for in vivo mouse model study?
Did some search. There are so many. And also don't know whether the usages are tricky or not. Appreciate if you can give me some recommendations.
Thank you Saamarthy and Priyankaa for your recommendations.
Thank you Nicole for your remind.Following
- Do you have a formal curriculum to teach radiology residents how to perform hands-on ultrasound?
It can be difficult to find the time to teach radiology residents a formal hands-on ultrasound curriculum in the setting of a busy clinical ultrasound service. The pressures of daily workflow and patient throughput often put service needs before education. Has your institution developed a formal curriculum for hands-on ultrasound education?
I would like to develop an e-learning program for you.Following
- How to determine which attributes to use by applying SVM-RFE?
I have some questions on classification using Support Vector Mahine Recursive Feature Extraction using WEKA. RFE gives a final ranking for the attributes however one need a method to decide which featuers to select from the final ranking. i am dealing with binary classification and have a set of features to discriminate between patients and healthy individuals but my dataset is unbalanced (have a few samples from patients) and need some help regarding these questions:
- Should i normilize the data or not? when and why we normilize the data?
- using SVM-RFE what is the best method to decide which features should be condidered to build the classifier and which not (sensitivity, accuracy, kappa statistic,....) considering that i am dealing with unbalanced data
at first you should consider your training set (positive and negative sets). this is very important to decide which features should be used. when you can't decide based on your data, it's better to use feature selection tools or algorithms. for example you can use PCA to rank your features and select optimum features to develop your SVM.Following
- Do you have experience of starting a double-blind journal in engineering?
I am thinking to start a double-blind journal in engineering, in the next year or so. Having a better picture of the complexity of such project would be very helpful to me. Thanks!
@Valeria, I find the idea interesting, but I see a possible debate around what would be the criterion for 'best paper'. I see that some journals give access to the most viewed/downloaded papers, but is that really a sign of quality? That would certainly limit the chances of publications from less popular or established topics to be awarded the 'prize'. An editorial award based on a pre-selection by the editors which would then have to be re-evaluated and voted for might work, but would also be a lot of work...Following
- Has anybody used the ENSEMBLE package from Julie Forman-Kay's lab?
I am interested in finding out if anybody has used the ENSEMBLE program from Julie Forman-Kay's lab at the University of Toronto. This package can be used to computationally model ensembles of protein unfolded states and then can select a sub-ensemble that agrees with experimental data such as RDCs, chemical shifts, SAXS data, PREs, and so forth.
I am having a terrible time getting the program to read and work with my data successfully despite having compared my own data to the example data provided and having consulted the program's documentation repeatedly.
If anybody has used this program successfully, would you please let me know? I'd like to ask you a couple of questions to try to figure out what might be wrong on my end. (I have of course tried to contact the program's authors directly a couple of times over the last month but have received no response, so my best hope now is somebody else out there who has used ENSEMBLE successfully.)
Thanks in advance.
I have recently used ENSEMBLE from Julie-Kay's group to model ensembles of denatured state. I can try my best to answer a few questions.
- Can anyone suggest me which binary classification I may use?
I quantified the features of the products, now I wish to include only those features which has a particular value or greater, how to classify? I have my own formula to score the features of the products.
You can use any standard classifiers like MLP, SVM, Decision Tree etc.Following
- Who would be interested in hiring a remote Instructional Development Specialist?
I work specifically on interdisciplinary models of inquiry. As a student, I am seeking to gain an entry level, full time position, appropriate for the further development of these programs as a new field of study. Follow me at email@example.com. and/or LinkedIn. My major is Interdisciplinary Studies with concentrations in Business Administration, Family Studies, and Applications of Teaching; all of which cross all disciplinary borders.
~ ADMST Map Model
~ Instructional Interdisciplinary Research Development Model
~ Family Business Interdisciplinary Researcher
~ Stem Instructional Interdisciplinary Research Development AssociationFollowing