academic

Performance of an large directory structure, networked application

I'm trying to find out what the performance of a large directory structure would be if deep directories were to be accessed on a shared, nfs filesystem. The structure would be excessively large, with 4 levels of nested directories, each level containing 1024 directories. (1024 at root, 1024 in a given subdirectory, and so on). This file...

Algorithm to determine how positive or negative a statement/text is

I need an algorithm to determine if a sentence, paragraph or article is negative or positive in tone... or better yet, how negative or positive. For instance: Jason is the worst SO user I have ever witnessed (-10) Jason is an SO user (0) Jason is the best SO user I have ever seen (+10) Jason is the be...

Which Data Mining Algorithm is the best?

Hi everyone! Long time listener, first time caller. I'm a full time SE during the day and a full time data mining student at night. I've taken the courses, and heard what our professors think. Now, I come to you - the stackoverflowers, to bring out the real truth. What is your favorite data mining algorithm and why? Are there any s...

Source Control for an Academic Research Group?

In contrast to most software development organizations, our little research group within a university department consists of a professor and a flow of grad and undergrad students, it's hard to retain any working knowledge beyond the research itself. Our backgrounds vary, and rarely involves much computer science background. (i have not ...

Help understanding academic notation for type system

I'm trying to understand an academic paper (pdf) about programming language design. In particular, it describes a lightweight version of Java called Featherweight Java. It has typing rules with notation like this: x_ : C_, this : C |- e0 : E0 E0 <: C0 class C extends D {...} if mtype(m,D) = D_->D0, then C_ = D_ and C0 = D0 -----...

Regular expression for finding a regular expression?

Does anyone have code for finding a file that contains a regular expression? I would assume you could have two different flavors, one for BREs and one for EREs. You would think some kind of test suites would have something like an isRegex() test. Can anyone have any code? Looking for something comprehensive of course. I see this was...

Entropy repacking

I have been tossing around a conceptual idea for a machine (as in a Turing machine) and I'm wondering if any work has been done on this or related topics. The idea is a machine that takes an entropy stream and gives out random symbols in any range without losing any entropy. I'll grand that is a far from rigorous description so I'll g...

Fun with md5 - digests of digests

Two questions actually: 1) Does there exist a 128-bit number whose md5 hash is itself? X == md5(X) - does 'X' exist and can it be found without brute force? 2) Does there exist two 128-bit md5 digests that hash to each other? Y == md5(X) && X == md5(Y) - do 'X' and 'Y' exist and can they be found without brute force? Related: ...

Identity column maximum value in SQLite DBs

I have a purely academic question about SQLite databases. I am using SQLite.net to use a database in my WinForm project, and as I was setting up a new table, I got to thinking about the maximum values of an ID column. I use the IDENTITY for my [ID] column, which according to SQLite.net DataType Mappings, is equivalent to DbType.Int64. ...

Academic papers concerning Task changes and productivity?

I'm currently writing up a technical report for a course, and I'm to source at least one academic/scientific paper, which is difficult since my focus is on programming (It's an general Engineering course, so for every engineering but Software it's much easier to find a relevant paper to your current project) I want to just briefly use t...

Does "if ([bool] == true)" require one more step than "if ([bool])"?

This is a purely pedantic question, to sate my own curiosity. I tend to go with the latter option in the question (so: if (boolCheck) { ... }), while a coworker always writes the former (if (boolCheck == true) { ... }). I always kind of teased him about it, and he always explained it as an old habit from when he was first starting progr...

Where can I find good open source code flow visualization software?

I am working on an academic research regarding some very long functions in the Linux kernel (link, link). For that research, I would like to use some code flow visualization tool, that would be able to plot a graph in which each vertex is a decision point and each edge is a piece of code which runs in a consequent way. Do you know of a...

Optimal Multi-page Navigation

I have encountered many web sites and even desktop applications that have a breadcrumb type control to navigate pages of information. For example, given X pages where the user is currently on page N, SOFU has a bread crumb control that presents page navigation in the form of: (X[N-1])(X[0])...(X[N-2])(X[N-1])(X[N])(X[N+1])(X[N+2])...(...

Code that causes physical effects in hardware?

A couple of years ago, I remember reading about an academic project that executed a specific sequence of instructions whose effect was to cause the targeted processor to catastrophically overheat and fail, by exceeding the tolerance limits of the processor's design. It was interesting because it was the only example I've ever seen of a p...

Can someone please explain the difference between Big-O and Little-O Notation?

I'm having trouble distinguishing between these these two. Can someone please explain the differences to me? I'm a little slow, so examples would probably help. Thanks ...

Prove that binary trees with the same inorder and preorder traversals are identical?

Does anybody know how to prove that if two binary trees have the same inorder and preorder traversals, then they are identical? (perhaps by showing that you can't have two different binary trees with identical inorder and preorder traversals) Alternatively, show a case that would disprove this, or show why can't it be done? (I'll admit...

What is an exciting area of database research?

I'm in graduate school and about to start a project related to databases. The professor has provided a list of topics for us to choose from, but we are also free to suggest something else we're personally interested in. The basic format of the project is quite simple: I'll study 2-3 research papers related to the area I end up choosing...

Top k problem - finding usage for my academic work

Top k problem - searching BEST k (3 or 1000) elements in DB There is fundamental problem with relational DB, that to find top k elems, there is a need to process ALL rows in table. Which make it useless on big data. I'm making application (for university research, not really my invention, I'm implementing and trying to improve origina...

Where can I take .NET courses in San Francisco?

I hope this question is considered programing related. I've been learning and using .NET for my job for over a year now. I've been using it to write plug-ins for programs we use in the office and a couple stand alone utilities. I don't work at a tech company, so there are very few people at the company that I can get any support from. Th...

Is the C# language a Microsoft product?

I am proofing my thesis and I am wondering how I should describe the language that I used Microsoft C-Sharp (C#) C-Sharp (C#) C# C# and the Microsoft .NET Framework Combinations of, or something else? ...