Questions tagged [classification]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
2
votes
1answer
512 views

How to tackle different sample size in the training set in SVM

I have to train a SVM for a classification problem. I have some strings that are the paths in a deterministic finite automata (DFA). If the alphabet is -01- then possible strings are 011101110 or ...
5
votes
1answer
6k views

Showing that Bayes classifier is optimal

Consider domain $X$, label set $ Y=\{0,1\}$ and the zero-one loss. Given any probability distribution D over $ X\times \{0,1\} $, we've defined the Bayes classifier $ f_D $ to be- $$ f_{D}(x)= \...
2
votes
1answer
71 views

Classifying objects by set proximity

The project I'm working on has a number of objects arranged in overlapping sets. I need to classify them by whether they have a trait or not, using pre-classified objects that they are connected to (...
1
vote
0answers
57 views

Machine Learning Algorithm Recommendation For Sensor Data [closed]

I would like to classify data coming from a sensor. In the literature Hidden Markov Model and SVM are used, but I would like to improve results with another methods.The picture how data and classes ...
1
vote
1answer
2k views

What is the different between Dijsktra's algorithm and KNN?

I am implementing machine learning software and in my case, I am using K-nearest neighbour classifier to get the task done. So far, I am trying to understand how Dijkstra's algorithm that has been ...
1
vote
2answers
488 views

Keywords for classification of 2D time series data?

Trying to find the right search terms for literature on classifying 2D time series data. I am looking at data from positional tracking of a swarm of insects over time. I have example datasets for ...
1
vote
1answer
66 views

Question about handwritten numbers recognition with limited data set

I have a an assignment to make a classifier for hand-written numbers with a limited data set of 500 samples. I am currently using python, I tried sklearn SVC with linear classifier and I got an ...
1
vote
1answer
225 views

How does an image classifier select relevant features?

I am trying to understand cascade classifiers for computer vision. I use OpenCV Traincascade for now and successfully trained some cascades. However I am trying to grasp the whole process. One thing ...
0
votes
0answers
50 views

Genetic algorithms, Pittsburg - Reach a decision from a set of rules

Consider a binary classification problem. In the Pittsburg approach each member of the population represents a set of rules. Each rule encodes information regarding the data features (that is, the ...
3
votes
2answers
269 views

Language Classification + AWS ML: what am I doing wrong?

I'm evaluating Amazon's machine learning platform, and thought that I would give it a "simple" classification problem first. As a disclaimer, I am quite new to machine learning (hence my interest in ...
4
votes
0answers
141 views

What are the best features to identify heads from any angle?

I want to automatically track heads in CCTV records. Sometimes I need to re-identify heads because of multiple heads crossing each other. So I continually need to extract features from tracked heads ...
0
votes
1answer
39 views

What is it called when you classify words into categories, but not by part of speech?

I'm looking to classify words into type categories like sushi to food, baseball to ...
1
vote
0answers
73 views

Problem with the motivation of penalized logistic regression

The following is a motivation for penalized logistic regression in some lecture notes I'm following: Although the cost-function for logistic regression is lower bounded by 0 we get issues if ...
3
votes
1answer
294 views

machine learning classification with financial instrument/time series data

I am new to machine learning and have started brainstorming some model ideas that involve financial instrument/time series data. I was thinking it might be useful to use a classification algorithm to ...
0
votes
0answers
313 views

Support Vector Machines vs K-Nearest Neighbors

Let's say we have trained a Support Vector Machine with a Gaussian Kernel. When we feed our model an example, it classifies it based on its similarity to landmarks (distance to examples in our ...
3
votes
1answer
238 views

What method of collective recogintion to use for digits recognition?

The structure of the question is as follows: at first, I provide the concept of collective recognition, further I provide explanation of the various methods of group classification that I found, in ...
4
votes
2answers
2k views

What is a sparse classifier?

Given a two-dimensional data set where each point is labeled $ \{0,1\}$, I want to implement a sparse classifier with $L_p \ \text({ 0<p \leq 1) }$. I have been reading on logistic regression and ...
1
vote
1answer
67 views

Find string patterns preferably in regex for string streams

I am trying to classify the data in a database columns. DB has about 90 million entries.The main goal is to find different patterns in columns to leverage it for create look alike data. The data ...
2
votes
2answers
6k views

Simple majority classifier question

one of my training questions for my exam is the following one: Suppose you are testing a new algorithm on a data set consisting of 100 positive and 100 negative examples. You plan to use leave-...
2
votes
1answer
762 views

Dynamically Learning Haar Cascade (in OpenCV)

I am new to computer vision so please excuse me if this question is very simple. I am trying to learn how to use the Haar Cascade creation tool provided with OpenCV to train a cascade classifier. It ...
-2
votes
1answer
57 views

classifier accuracy

I’m developing a mutual information based classifier, the output of the classifier is {{0,4,5,6},{1,2,3},{7},{8},{9}} and the correct decision output is {{0,1,2,4,5,6,9},{3},{7,8}}. How to compute the ...
0
votes
2answers
428 views

Can I use machine learning to predict someone will buy something in a specific time? [closed]

I have a dataset which has timestamp and goods variable for an object like the following example: On Moday, John bought Beer, chicken, pizza. On Tuesday, John bought pizza, pork and beef. On ...
3
votes
1answer
88 views

Classification training data, but regression prediction

Suppose I'm performing machine learning on a simple dataset, and have a bunch of training data of the form: ...
0
votes
0answers
1k views

Classifying responses into yes/no

So my problem is as follows: I get responses (such as "yeah whatever", "yes do it", "no don't do it", "nah", "yeah do it" etc.) and I need to classify them into either "yes" or "no" i.e. a binary ...
1
vote
1answer
29 views

What is the need of re-sampling the image for HOG features?

I read Dalal and Triggs paper for HOG description and a blog Chris McCormick HOG regarding the same. The blog says that the image needs to be re-sampled at different scales to recognize different ...
2
votes
1answer
73 views

What is the Best and easiest way to create a Classifer for Sentiment Analysis [closed]

Sentiment analysis using Machine Learning is a hot topic. In the present situation when a person doesn't have a problem in having the training data set then which way should we create the classifier ...
1
vote
0answers
35 views

Classification with optional/catchall attributes

Context Let $S$ be a set of objects, each object $S_k$ containing a set of attributes $A_k\subseteq A$, where $A$ is a global set of attributes. Suppose each attribute $a_k\in A$ can take on integer ...
1
vote
0answers
16 views

How do you set the number of words in the visual dictionary?

How do you set the number of words in the visual dictionary? I tried to understand the different steps to obtain the visual dictionary first: Feature detection: Examines every pixel to see if there ...
1
vote
0answers
255 views

Knowledge Vault - Please explain the local closed world assumption

Background I'm currently reading a paper on the google knowledge vault here : http://www.cs.cmu.edu/~nlao/publication/2014.kdd.pdf. I'm having trouble with the Local Closed World Assumption (LCWA). ...
3
votes
1answer
84 views

What is a visual bag of words and how is it implemented?

I'm currently working on implementing a bag of visual words in Python. I get the general gist of how it works but I can't seem to find any sources that explain it in more detail to a level where I can ...
1
vote
1answer
489 views

NLP Classification: rule-based approach providing high precision but low recall

In NLP, rule-based/linguistic approaches are usually said to provide relatively high precision but low recall compared to for example machine learning approaches. I think this is often true for almost ...
4
votes
1answer
63 views

Simple Bayesian classification with Laplace smoothing question

I'm having a hard time getting my head around smoothing, so I've got a very simple question about Laplace/Add-one smoothing based on a toy problem I've been working with. The problem is a simple ...
1
vote
0answers
52 views

Why naive Bayes performs better?

I have found that naive Bayesian classifier performs much better than classification using mixture of multivariate Gaussians. Here is the problem: I have a set of objects with attached features (10 ...
1
vote
2answers
6k views

Effect of value of k in K-Nearest Neighbor

In K-Nearest Neighbor the value of k decides the accuracy of classification. What are the pros and cons of choosing smaller value for k and larger value for k?
1
vote
0answers
104 views

How to train a Conditional Random Field/Markov Random Field Model for Object Classification in images given the features?

I want to classify superpixels in a image using a Markov Random Field/ Conditional Random Field model but have found no place that can help me with this (references don't even show how the network is ...
0
votes
2answers
509 views

Backpropagation for 'Classification' Neural Network

Question: How does one formulate a back propagation algorithm (either batch, gradient, anything that works) for a neural net, playing a game of Tic Tac Toe? (Java is being utilized) Scenario: There ...
2
votes
1answer
439 views

What kind of Neural Network (if any) could fit two sets of data points?

I have two datasets, one of animal migration patterns (collected over the course of a couple years) that consists of many points on an x, y plane (latitude, longitude), and the other of ocean surface ...
2
votes
2answers
20k views

Differences between SISD, SIMD and MIMD architecture (Flynn classification)

I have a problem with classifying certain CPUs to the proper classes of Flynn's Taxonomy. 1. Zilog Z80 According to this article on Sega Retro, Z80 has limited abilities to be classified as SIMD: ...
1
vote
1answer
33 views

Classification problem where one attribute is a vector

Hello I am a layman trying to analyze game data from League of Legends, specifically looking at predicting the win rate for a given champion given an item build. Outline A player can own up to 6 items ...
3
votes
0answers
460 views

What is the activation function, label and loss function for Hierachical Softmax

Several papers(1 (originator), 2, 3) suggest the use of Hierachical Softmax instead of softmax for classification where the number of classes is large (eg many thousand). I haven't been able to get ...
0
votes
0answers
252 views

Optimal Design of Cascaded Classifier

Consider a cascade of classifiers and a binary classification task. Cascade consists of some number of strong classifiers (n) each of which consists of some number of weak classifiers (m_i, where i = ...
1
vote
1answer
1k views

Online supervised learning algorithm

I have labeled examples coming in on the fly, thus I need to create a classifier from sequential data instead of a static example set. Incoming data is fully labeled, there are no unlabeled examples. ...
0
votes
1answer
1k views

Transformation from one feature space to another

I have found the following example: As an example consider the case when the input space $ {\mathcal{X}}$ consists of images of $ 16\times 16$ pixels, i.e. $ 256$ dimensional vectors, and we ...
0
votes
0answers
39 views

Finding number of clusters in a dataset

I am learning the basics of data classification using competitive learning, and am somewhat confused regarding the way this is implemented. I understand at the start an amount N of prototypes is ...
2
votes
1answer
92 views

Classification when some classes are dependent

I think my problem can easier be explained via an example: Assume we have a dataset containing the images of 10 different mammals, let's say lion, elephant, cat, ... and horse. We have a 20-class ...
8
votes
1answer
37k views

Size of decision tree and depth of decision tree

I'm doing some classification experiments with decision trees ( specifically rpart package in R). By setting the depth of a decision tree to 10 I expect to get a small tree but it is in fact quite ...
0
votes
1answer
205 views

How does the ID3 Algorithm differ from a generic Decision Tree learning algorithm

Based on the notes of my Machine Learning lecturer, I am struggling to understand how the two algorithms differ? Both seem to select the most informative feature A (based on least entropy), then ...
0
votes
1answer
4k views

Is a KNN-Classifier memory intensive?

In my opinion it seems fairly obvious that a $k$ nearest neighbours (KNN) Classifier would be fairly expensive in terms of memory, as the model is the training set itself. However, any notes I've read ...
1
vote
1answer
187 views

Random Forest closed loop

I'm using the Random Forest algorithm for classification. I have some variable to use as features in input, but I was wondering if I can use the output of the classification itself as input. Suppose, ...
0
votes
0answers
83 views

Learn feature value range for a classification

Which domain does this problem belong to? Given a set of products some are classified as cheap and some not. The task is to determine the price range (probabilistic) for cheap products. Supervised ...