machine-learning

Version Spaces algorithm examples

I'm asked to learn a concept using the Version Spaces (VS) algorithm that is able to predict life expectancy given a set of samples and data. The class examples we saw are kind of trivial compared to the assignment we got now. In particular I'm unsure about how to decide on the granularity of the concept hierarchies given that the data i...

Hierarchy of meaning

I am looking for a method to build a hierarchy of words. Background: I am a "amateur" natural language processing enthusiast and right now one of the problems that I am interested in is determining the hierarchy of word semantics from a group of words. For example, if I have the set which contains a "super" representation of others, i...

Algorithm to generate numerical concept hierarchy

I have a couple of numerical datasets that I need to create a concept hierarchy for. For now, I have been doing this manually by observing the data (and a corresponding linechart). Based on my intuition, I created some acceptable hierarchies. This seems like a task that can be automated. Does anyone know if there is an algorithm to gene...

Different weights of false positive and false negative in neural network?

I have a yes/no classification problem, where false positives are worse than false negatives. Is there a way to implement this fact into neural network especially in MATLAB's Neural Network Toolbox? ...

What algorithms are suitable for this simple machine learning problem?

I have a what I think is a simple machine learning question. Here is the basic problem: I am repeatedly given a new object and a list of descriptions about the object. For example: new_object: 'bob' new_object_descriptions: ['tall','old','funny']. I then have to use some kind of machine learning to find previously handled objects that h...

Pruning Deductions in Expert Systems

In a rule system, or any reasoning system that deduces facts via forward-chaining inference rules, how would you prune "unnecessary" branches? I'm not sure what the formal terminology is, but I'm just trying to understand how people are able to limit their train-of-thought when reasoning over problems, whereas all semantic reasoners I've...

How To Design Eurisko

The program Eurisko was developed by Douglas Lenat in the late 70s and 80s. It's allegedly adept at learning general patterns and heuristics, and at improving it's own performance. Naturally, Lenat has never released the source code, and has published very little information about the exact inner workings of the program. So, in lieu of a...

Machine Learning Algorithm for Predicting Order of Events?

Simple machine learning question. Probably numerous ways to solve this: There is an infinite stream of 4 possible events: 'event_1', 'event_2', 'event_4', 'event_4' The events do not come in in completely random order. We will assume that there are some complex patterns to the order that most events come in, and the rest of the event...

Applications for the Church Programming Language

Has anyone worked with the programming language Church? Can anyone recommend practical applications? I just discovered it, and while it sounds like it addresses some long-standing problems in AI and machine-learning, I'm skeptical. I had never heard of it, and was surprised to find it's actually been around for a few years, having been a...

Convergence criterion for (batch) SOM (Self-Organizing Map, aka "Kohonen Map")?

I like to stop the execution when Batch SOM becomes converged. What error function can I use to determine the convergence? ...

Issues in Convergence of Sequential minimal optimization for SVM

I have been working on Support Vector Machine for about 2 months now. I have coded SVM myself and for the optimization problem of SVM, I have used Sequential Minimal Optimization(SMO) by Mr. John Platt. Right now I am in the phase where I am going to grid search to find optimal C value for my dataset. ( Please find details of my project...

Calculating Nearest Match to Mean/Stddev Pair With LibSVM

I'm new to SVMs, and I'm trying to use the Python interface to libsvm to classify a sample containing a mean and stddev. However, I'm getting nonsensical results. Is this task inappropriate for SVMs or is there an error in my use of libsvm? Below is the simple Python script I'm using to test: #!/usr/bin/env python # Simple classifier t...

Nominal Attributes in LibSVM

When creating a libsvm training file, how do you differentiate between a nominal attribute verses a numeric attribute? I'm trying to encode certain nominal attributes as integers, but I want to ensure libsvm doesn't misinterpret them as numeric values. Unfortunately, libsvm's site seems to have very little documentation. Pentaho's docs s...

Question on multi-probe Local Sensitive Hashing

Hey guys sorry to be asking this kind noob question, but because I really need some guidance on how to use Multi probe LSH pretty urgently, so I did not do much research myself. I realize there is a lib call LSHKIT available that implemented that algorithm, but I have trouble trying to figure out how to use it. Right now, I have a few ...

Any Naive Bayesian Classifier in python?

Dear Everyone I have tried the Orange Framework for Naive Bayesian classification. The methods are extremely unintuitive, and the documentation is extremely unorganized. Does anyone here have another framework to recommend? I use mostly NaiveBayesian for now. I was thinking of using nltk's NaiveClassification but then they don't think t...

Prolog: Not executing code as expected.

Basically I am attempting to have an AI agent navigate a world based on given percepts. My issue is handling how the agent moves. Basically, I have created find_action/4 such that we pass in the percepts, action, current cell, and the direction the agent is facing. As it stands the entire code looks like: http://wesnoth.pastebin.com/kdNv...

When to choose which machine learning classifier?

Suppose I'm working on some classification problem. (Fraud detection and comment spam are two problems I'm working on right now, but I'm curious about any classification task in general.) How do I know which classifier I should use? (Decision tree, SVM, Bayesian, logistic regression, etc.) In which cases is one of them the "natural" fi...

Neural Network: Handling unavailable inputs (missing or incomplete data)

Hopefully the last NN question you'll get from me this weekend, but here goes :) Is there a way to handle an input that you "don't always know"... so it doesn't affect the weightings somehow? Soo... if I ask someone if they are male or female and they would not like to answer, is there a way to disregard this input? Perhaps by placing ...

what is the best way to generate fake data for classification problem ?

i'm working on a project and i have a subset of user's key-stroke time data.This means that the user makes n attempts and i will use these recorded attempt time data in various kinds of classification algorithms for future user attempts to verify that the login process is done by the user or some another person. (Simply i can say that th...

How to segment text images using MATLAB?

It's part of the process of OCR,which is : How to segment the sentences into words,and then characters? What's the candidate algorithm for this task? ...