Questions tagged [machine-learning]

Machine Learning is a subfield of computer science that draws on elements from algorithmic analysis, computational statistics, mathematics, optimization, etc. It is mainly concerned with the use of data to construct models that have high predictive/forecasting ability. Topics include modeling building, applications, theory, etc.

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1answer
227 views

Using GPS signal, determine is this person driving a cab

New York City provides tens of gigs of data of taxi routes all over the city. What I'd like to do, is use this data (or some other method), to come up with an algorithm that can take a persons GPS ...
2
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0answers
138 views

Parameters for CART tree

I'm using fitctree function from Matlab to fit a CART tree to my dataset (10'000 data points, 20 features). First, how can I exactly prune it and to what level should the tree be pruned? I think I ...
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2answers
963 views

Hierarchical Clustering customized Linkage function

In my clustering project, I need to customize the linkage function, so that after each cluster merging I can update the inter-cluster distance in my own way. Currently I'm using scikit-learn ...
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1answer
410 views

Character recognition neural net topology/design

I'm building a neural net for classifying characters in pictures. The input can be any character a-z, lowercase and uppercase. I only care about classifying the characters, and not the case, so the ...
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0answers
139 views

Heterodox use of Deep Learning to find hidden patterns

I would appreciate your comments/help about a strategy I am applying in one of my analysis. In short, my case is: 1) My data have biological origin, collected in a period of 120s, from a subject ...
5
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1answer
192 views

how can I generate a Bernoulli block mixture model in matlab?

I am trying to write the code of a Bernoulli block mixture model in matlab, but am facing an error every time I run the function. In particular, I'm having a problem with how to relate the ...
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2answers
111 views

In Neural Nets, why Use Gradient Methods as Opposed to Other Metaheuristics?

In training deep and shallow neural networks, why are gradient methods (e.g. gradient descent, Nesterov, Newton-Raphson) commonly used, as opposed to other metaheuristics? By metaheuristics I mean ...
2
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2answers
352 views

Algorithm Suggestion For a Specific Problem

I'm working on a problem where in I have some data sets about some power generating units. Each of these units have been activated to run in the past and while activation, some units went into some ...
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0answers
2k views

Image Captioning example in keras Approach?

I have used the keras example code of Image Captioning in that I have used the VGG pretrained model for extracting image features(4096) and for text part I have done indexing to the unique words and ...
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1answer
103 views

How would I map categories between two similar but different sets of categories

Having multiple sets of categories from different listings sites (e.g. Yelp, yellowpages.com, Google My Business...). I want to figure out what category X on one site is on another site. We have ...
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1answer
291 views

Understanding ConfusionMatrix for Google Prediction API

I'm trying to analyze my training model, Google Prediction API provides analyze method to get insights for the model. Currently I want to improve confidence levels, for my predictions, I haven't found ...
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1answer
95 views

Questions regarding deep learning?

I have questions regarding this Normalized weights and Initial inputs video on Udacity course Deep Learning In this video the lecturer talks about variables that go into Big-loss function should have ...
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2answers
2k views

IID violation in machine learning

Imagine I'm collecting some training data. Lets say I collect a 30minute time series from 1000 people so I have 1000 observations (rows) in my feature matrix. I train some model (lets say a neural ...
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3answers
1k views

How to predict an approximate weekly/monthly number, when the Unique Daily Visitors for that week/month are already known

I am trying to come up with a formula or machine learning algorithm using which I can approximately predict the weekly or monthly users. What to keep in mind is that I already have counts for the ...
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2answers
3k views

Are real analysis and measure theory essential to learn for data science? [closed]

Some people say data scientists don't necessarily need to know real analysis and measure theory, but for others, real analysis and measure theory are very important for the undersdanding of kernel ...
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1answer
804 views

Any Master Thesis Topics related to NoSQL and Machine Learning or Business Intelligence? [closed]

Im currently in the last year, and I want to do a masters thesis on a topic that has NOSQL and Machine Learning or Business Intelligence. In my topic i want for defintely NOSQL, so I want to add a ...
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1answer
119 views

Building Customers/Patient Profiles

I am looking for ideas on how to proceed with a situation. I have historical data of appointments for many users. I can (easily) predict their future behaviour (whether the next appointment will be ...
7
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1answer
444 views

Neural Networks: How to prepare real world data to detect low probability events?

I have a real world data set of credit borrowers (50,000 records). The set contains categories such as Married, Single, Divorced, etc. as well as continuous data such as Income, Age, etc. Some records ...
5
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1answer
3k views

Testing bimodality of data

I am trying to see if my data is multimodal (in fact, I am more interested in bimodality of the data). I performed dip test and it does evidence against unmodal data. However, I want to see, in ...
10
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2answers
569 views

implementing temporal difference in chess

I have been developing a chess program which makes use of alpha-beta pruning algorithm and an evaluation function that evaluates positions using the following features namely material, kingsafety, ...
10
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1answer
4k views

HOW TO: Deep Neural Network weight initialization

Given difficult learning task (e.g high dimensionality, inherent data complexity) Deep Neural Networks become hard to train. To ease many of the problems one might: Normalize && handpick ...
3
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1answer
204 views

Why doesn't AlphaGo expect its opponent to play the best possible moves?

In the game won by Lee Sedol, AlphaGo was apparently surprised by a brilliant and unexpected move from Lee Sedol. After analysing the logs, the Deep Mind CEO said that AlphaGo had evaluated a 1/10000 ...
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4answers
2k views

How is training data generated

Very new to Machine learning process. I am curious as to how researchers, companies, academics get training data for their research. Do they pay some users to train data. If yes, how do they ...
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4answers
4k views

Feature Extraction Technique - Summarizing a Sequence of Data

I often am building a model (classification or regression) where I have some predictor variables that are sequences and I have been trying to find technique recommendations for summarizing them in the ...
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2answers
189 views

Applying neural network for simple x^2 function for demonstration purpose [closed]

I have tried to train a neural network for a simple x^2 function I developed training data in excel. First column (X) is =RANDBETWEEN(-5,5) i.e random integer between -5 and 5 Second column ...
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3answers
1k views

K Means giving poor results

I have several user names and their salaries. Now I need to cluster user based on their salaries. I am using KMeans clustering and following is my code ...
2
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1answer
779 views

Encoding feature with tree-path data

What are the common techniques for encoding discrete features with tree-path value (e.g. file/folder path) without expanding tree into multiple features corresponding to each node? Update. Overall, ...
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0answers
541 views

Extract Product Attributes/Features

I've been assigned a task to extract features/attributes from product description. Levi Strauss slim fit jeans Big shopping bag in pink and gold I need to be ...
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1answer
47 views

Please suggest some simple functions that I can use to test my neural network implementation

I am a beginner and I have developed code in Octave to train a neural network (as part of Andrew Ng's coursera course). Now I would like to generate some datasets in Excel for simple mathematical ...
0
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1answer
939 views

How to retrieve the clustering results of rpart

I am using rpart package in order to create a segmentation of my data using decision tree. As final result I want to obtain a classification of my data. For exemple, if the rpart devide data into 3 ...
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1answer
26 views

Combinatoric system which using in bookies “S3” system

I am interested what type of combinatorics is using for following bookmakers system called "S3": We have N={1..8} events We build ...
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3answers
12k views

How to perform feature engineering on unknown features?

I am participating on a kaggle competition. The dataset has around 100 features and all are unknown (in terms of what actually they represent). Basically they are just numbers. People are performing ...
3
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1answer
2k views

Deriving Feature Map formula for Inhomogeneous Polynomial Kernel

How do we derive/extrapolate the feature map for inhomogeneous polynomial kernels for degree $d$, define as $$K(x, x^\prime) = \bigg( (x \cdot x^\prime) + c\bigg)^d$$ I know we don't need to know a ...
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0answers
17 views

Associating processes with load on the system

I am trying to find out the processes on our linux servers that are responsible for load on the system. We have an application server and an Oracle database server (both running Linux). The ...
3
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1answer
2k views

On the properties of Hyperbolic Tangent Kernel [closed]

How do Hyperbolic Tangent Kernels work? That is what is the intuition behind them? Can you provide proofs and examples for illustration? Hyperbolic Tangent Kernels are defined as: $$ K(x, x^\prime) = ...
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1answer
2k views

difference between logistic regression and binary logistic regression

In xgboost R package, there are two objectives given with booster gbtree. reg:logistic ...
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1answer
8k views

How do you calculate how dense or sparse a dataset is?

I'm looking deeper into collaborative filtering. One really interesting paper is "A Comparative Study of Collaborative Filtering Algorithms" http://arxiv.org/pdf/1205.3193.pdf In order to select ...
3
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0answers
370 views

What causes the error in a RNN to increase late in training?

I'm training a 2-layer, 1024 node, dropout of 0.5 RNN over natural text. Specifically, I'm using karpathy's char-rnn which I found to work quite well for most of my use cases. Sometimes however, late ...
11
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2answers
724 views

Neural net for server monitoring

I'm looking at pybrain for taking server monitor alarms and determining the root cause of a problem. I'm happy with training it using supervised learning and curating the training data sets. The data ...
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0answers
78 views

Error with Convolutional Neural Network (SGD?)

I'm implementing a CNN with Numpy and Scipy to solidify my understanding, but I'm encountering a rather strange problem. My layers are: input -> conv -> pool -> FC Here are the relevant functions: <...
1
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1answer
816 views

How would you categorise email subjects to find similar emails? [duplicate]

I have a list of email subjects like <XYZ> commented on <ABC> Weekly review for <Company> Your account is ready And I want to find patterns in ...
6
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1answer
153 views

Geometric Interpretation of Whether SVMs are performing well or not

I came across this research paper which contained this figure which talks about the center of mass (presumably, of the training dataset's datapoints?) and represents the solution of an SVM as ...
3
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1answer
117 views

Value Updation Dynamic Programming Reinforcement learning

Regarding Value Iteration of Dynamic Programming(reinforcement learning) in grid world, the value updation of each state is given by: Now Suppose i am in say box (3,2). I can go to (4,2)(up) (3,3)(...
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0answers
580 views

Machine Learning with fixed and variable inputs and multiple outputs

I've been doing machine learning and neural networks for a couple months, and finished a 5 months online course of it last year, but I'm struggling in an specific scenario: Let's say we've got this ...
6
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1answer
12k views

Implement MLP in tensorflow

There are many resources online about how to implement MLP in tensorflow, and most of the samples do work :) But I am interested in a particular one, that I learned from https://www.coursera.org/learn/...
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1answer
143 views

Expand or compact features?

I have a classification task for people with 3 categories. I want to apply machine learning for that. I have 10 sources of data, which have the same fields (say 4: age, job title, a number of ...
5
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2answers
818 views

How are clusters from DBSCAN sometimes non-convex?

I've been using clustering in my bag of ML techniques for quite some time now, and I've never found a satisfying answer to this question. In DBSCAN, we define a maximum radius with which to form ...
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0answers
88 views

Trend Decline Graph Normalization

I am working on a project that should predict Alarm based on the input data. I am trying to use a supervised learning algorithm. But I do not have the exact target value based on the input for feeding ...
6
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1answer
142 views

How are Hyperplane Heatmaps created and how should they be interpreted?

For nonlinear data, when we are using Support Vector Machines, we can use kernels such as Gaussian RBF, Polynomial, etc to achieve linearity in a different (potentially unknown to us) feature space ...
0
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1answer
159 views

Stanford NER - Increase probability for a certain class

I'm new to machine learning so I apologize if this question is silly. I'm using Stanford NER's english 4class classifier with good results. However, since my dataset is mostly focused on organizations,...

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