I got a weird H.W assignment in requirements engineering seminar .
I was digging through the entire net yet found no example for this one...
I need to find a problem from any engineering field (mechanics,medicine,chemistry,programming etc.) that the ERD model fails to give a complete/any answer to.
Can anyone show me some examples of a loss of information/process/entity while modeling only in ERD ?
maybe a point where I will need to compromise in order to continue modeling?
Or at least what are ERD's limitations ?
I need it to be an example for the limitation/disadvantage and not an example for a common mistake or bad modeling.
Well, ERD only deals with static aspects of the problem (i.e. the structure of the data that needs to be manipulated). All the information about the dynamic aspects of the problem will be lost if you only model using ERD
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TL;DR i'm currently creating a cross-platform mobile news aggregator, which will identify news articles from different publishers, but about the same topic, e.g. a celebrity passes away.
I believe I found an appropriate journal that can guide me through the steps 'Document Clustering with grouping and chaining algorithms'.
(https://www.aclweb.org/anthology/I05-1025.pdf)
However many of the steps are confusing me such as:
1) Document clustering
2) Grouping and chaining algorithms
3) Understanding equations such as the one below that I'll need to compute.
Any help on the matter, or a brief description of the steps would be greatly appreciated.
Thanks for the help.
I'm also interested in any experts in this field, and would love to use your knowledge as qualitative evidence for my project. If you'd be be up for it please DM, or drop a comment. Thanks again!
In my semester exams I got a question:
Draw class diagram and association diagram for the online booking of movie tickets.
I know how to draw class diagrams so I drew it, but I was confused regarding association diagrams.I took a chance and drew a diagram with my vague understanding.I only drew class boxes and showed associations between them while drawing association diagram,while in class diagram I showed all the relationships like aggregation,composition,inheritance etc.I don't know whether i was right or wrong because when I googled it I found nothing but the examples of class diagrams only.
I would appreciate deeply if anyone alleviate my confusion.thank you!
So, again after a long wait , I am going to answer my question and since it was me only who asked this, suggestions are welcome from the deep bottom of my heart.
Now , so far what I have concluded is that ( obviously after searching many a times on net ) there is nothing specific like Association diagram as such (I am darned of my university for asking question in this way) . If there is anything after all its the association relationships among classifiers which can be otherwise shown as a "association diagram*. So, here is the minute difference which I could make out :
CLASS DIAGRAMS:- Class diagram is basically a detailed one showing classes, their interfaces , attributes and also their relationships. As for example :
While in "association diagrams" ( I am considering for now it as association diagram), classes' attributes and their internal implementation is not given much importance ,all that is shown, is the type of relationships among them.As for example :-
NOTE-- Any kind person who finds any more relevant information regarding this topic, please put suggestions in the comments so that I can edit my answer, for better. Any one is also free to edit my post if he or she feels its right.
Ok this question is not exactly technical but very pertinent and current.
If you may have not heard Eureqa (http://creativemachines.cornell.edu/eureqa) is a machine learning (?) based tool that helps you find hidden equations and mathematical relationships within the data. It does sound futuristic and experimental and to a great degree it seems it is.
This is the relevant talk by Eureqa inventor Hod Lipson
http://www.youtube.com/watch?v=Xja6sLl6dVg entitled Mining experimental data.
So i believe this can become popular amongst many R users .
On the official site one can obtain Eureqa clients for MATLAB, Mathematica, Python etc but none so far for R.
So this question is just what it is , is anyone of you working on creating one...or if you know this project do you know what it will take to make one ?
I asked the same question on the Eureqa group a few months ago. Here's the link:
http://groups.google.com/group/eureqa-group/browse_thread/thread/cb251327b50dbd4f
The last entry has the following links:
http://r.eureqa.ivi.eu.com/
http://groups.google.com/group/eureqa-r
I haven't tried this, so I don't know if it works. If you try it, please post your results.
I have the responsibility of ensuring that a colleague who is just learning R knows the basics before a course where that is a requirement. The colleague has gone through a couple of tutorials so hopefully she is ok, but I would like to give her a test to gauge it.
I was therefore wondering if anyone knew if there were any materials on the web that would be suitable? and is possible had both questions and answers.
PS Cross-posted to r-help#stat.math.ethz.ch
There is a whole set of exercises with solutions from the book Data Analysis and Graphics Using R. (Maindonald & Braun, 2nd edn, CUP 2007) available online : http://maths.anu.edu.au/~johnm/r-book/2edn/exercises/
Next to that, a quick search using the obscure randomized pagecollector Google brought to me a set of exercises where you can pick out whatever you want. Try the magic phrase "R exercises". ;)
Some I found interesting :
http://www2.imperial.ac.uk/~das01/RCourse/Exercises.pdf (very nice)
http://dial.liacs.nl/Courses/MicroArrayDataAnalysis/Exercises/Introduction_to_R_Exercises_Nov_2004.pdf (rather basic)
http://www.shlrc.mq.edu.au/masters/students/raltwarg/altwargslp802.html (rather basic)
If this is just a one time single person evaluation then a oral style exam is probably going to tell you a lot more than a set of fixed problems. Get a data set and have her read it into R, do some basic data manipulation, a couple of plots, and a standard analysis or two. Based on what she does well or has a challenge with you can modify the direction that you have things go and what additional questions you ask.
I'm interested in learning more about pattern recognition. I know that's somewhat of a broad field, so I'll list some specific types of problems I would like to learn to deal with:
Finding patterns in a seemingly random set of bytes.
Recognizing known shapes (such as circles and squares) in images.
Noticing movement patterns given a stream of positions (Vector3)
This is a new area of experimentation for me personally, and to be honest, I simply don't know where to start :-) I'm obviously not looking for the answers to be provided to me on a silver platter, but some search terms and/or online resources where I can start to acquaint myself with the concepts of the above problem domains would be awesome.
Thanks!
ps: For extra credit, if said resources provide code examples/discussion in C# would be grand :-) but doesn't need to be
Hidden Markov Models are a great place to look, as well as Artificial Neural Networks.
Edit: You could take a look at NeuronDotNet, it's open source and you could poke around the code.
Edit 2: You can also take a look at ITK, it's also open source and implements a lot of these types of algorithms.
Edit 3: Here's a pretty good intro to neural nets. It covers a lot of the basics and includes source code (albeit in C++). He implemented an unsupervised learning algorithm, I think you may be looking for a supervised backpropagation algorithm to train your network.
Edit 4: Another good intro, avoids really heavy math, but provides references to a lot of that detail at the bottom, if you want to dig into it. Includes pseudo-code, good diagrams, and a lengthy description of backpropagation.
This is kind of like saying "I'd like to learn more about electronics.. anyone tell me where to start?" Pattern Recognition is a whole field - there are hundreds, if not thousands of books out there, and any university has at least several (probably 10 or more) courses at the grad level on this. There are numerous journals dedicated to this as well, that have been publishing for decades ... conferences ..
You might start with the wikipedia.
http://en.wikipedia.org/wiki/Pattern_recognition
This is kind of an old question, but it's relevant so I figured I'd post it here :-) Stanford began offering an online Machine Learning class here - http://www.ml-class.org
OpenCV has some functions for pattern recognition in images.
You might want to look at this :http://opencv.willowgarage.com/documentation/pattern_recognition.html. (broken link: closest thing in the new doc is http://opencv.willowgarage.com/documentation/cpp/ml__machine_learning.html, although it is no longer what I'd call helpful documentation for a beginner - see other answers)
However, I also recommend starting with Matlab because openCV is not intuitive to use.
Lot of useful links on this page on computer vision related pattern recognition. Some of the links seem to be broken now but you may find it useful.
I am not an expert on this, but reading about Hidden Markov Models is a good way to start.
Beware false patterns! For any decently large data set you will find subsets that appear to have pattern, even if it is a data set of coin flips. No good process for pattern recognition should be without statistical techniques to assess confidence that the detected patterns are real. When possible, run your algorithms on random data to see what patterns they detect. These experiments will give you a baseline for the strength of a pattern that can be found in random (a.k.a "null") data. This kind of technique can help you assess the "false discovery rate" for your findings.
learning pattern-recoginition is easier in matlab..
there are several examples and there are functions to use.
it is good for the understanding concepts and experiments...
I would recommend starting with some MATLAB toolbox. MATLAB is an especially convenient place to start playing around with stuff like this due to its interactive console. A nice toolbox I personally used and really liked is PRTools (http://prtools.org); they have an implementation of pretty much every pattern recognition tool and also some other machine learning tools (Neural Networks, etc.). But the nice thing about MATLAB is that there are many other toolboxes as well you can try out (there is even a proprietary toolbox from Mathworks)
Whenever you feel comfortable enough with the different tools (and found out which classifier is perfomring best for you problem), you can start thinking about implementing the machine learning in a different application.