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Questions tagged [machine-learning]

Methods and principles of building "computer systems that automatically improve with experience."

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1answer
15 views

Predicting descrete value problem in regression or classification

In machine learning, regression algorithms attempt to estimate the mapping function (f) from the input variables (x) to numerical or continuous output variables (y). I have one usecase where I ...
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0answers
25 views

How to write a predict function for mlr predict to upload in AzureML as webservice?

I am trying to upload a R Model in AzureML as webservice, for the linear model like Regression I use ...
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2answers
41 views

How to build an image dataset for CNN?

I don't understand how images are actually fed into a CNN? If I have a directory containing a few thousand images, what steps do I need to take in order to feed them to a neural network (for instance ...
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1answer
13 views

Regularization: global or layerwise?

Keras gives you the option to apply regularization differently to different layers. I mean, why not? Though when I first learned about neural nets (from ESL), I thought of it as a global parameter. ...
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1answer
25 views

How to use Machine Learning to discover important biomarkers in an unbalanced small data set

I have a project which I am just starting out, I am only just learning machine learning and statistics so I am somewhat unsure as to what approaches will be good to start off with, and I am sorry if ...
2
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1answer
40 views

multi-output regression problem with tensorflow

number of features: 12 , -15 < each feature < 15 number of targets: 6 , 0 < each target < 360 number of examples: 262144 my normalization: I normalized the features so that they are ...
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1answer
21 views

oversampling data with subclass

Oversampling of under-represented data is a way to combat class imbalance. For example, if we have a training data set with 100 data points of class A and 1000 data points of class B, we can over ...
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1answer
31 views

Residual plot is tight to zero, but low R2 score

Hi I am a beginner at data science, and currently trying to use Gradient Boost Regressor to predict car price based on several attribute such as machine capacity, car brand, car type etc. I am ...
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0answers
11 views

Ordinary Least Squares - P values differing in Jupyter and Spyder for the same Multiple Linear Regression problem

I am trying out a Multiple Linear Regression problem from a Udemy course. The course used Spyder to run the models. When I used the same code on Spyder, I got the same responses. To recap and make my ...
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1answer
32 views

An ambiguity in SVM equations about misclassified data

I have encountered an ambiguity in SVM equations. As is stated in Chris Bishop's machine learning book, the optimization goal in SVM is to maximize this function: $$C\sum\limits_{n = 1}^N {{\xi _n}} ...
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0answers
25 views

What does E mean in the GAN equation?

I don't understand what "E" means in the GAN equation. It would be great, if someone could explain what it means. Is it entropy or expected value or something else? I couldn't manage to find the ...
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1answer
29 views

Machine learning with sklearn vs. scipy stats

I've created 50 random x and y points (with slope of y = 2x-1). First, I used Linear Regression from sklearn to fit the model onto my dataset where I got a slope of ...
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1answer
10 views

Sampling Big Data for Predictive Analytics in Python

In practice, how does one go about sampling a from big data set (eg. +/- 50 million distinct observations) to perform ML using Python? Most non-parametric models (e.g., SVM, ensemble models) start to ...
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1answer
33 views

Choosing a suitable learning rate based on validation or testing accuracy?

I have simulated a neural network with different learning rate, ranging from 0.00001 to 0.1, and recording each test and validation accuracy. The result i obtained is as below. There is 50 epoch for ...
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2answers
44 views

How long would it take to become proficient in machine learning for someone with a non-statistical mathematical background?

I am currently a postdoc and my PhD was in applied mathematics in the area of numerical analysis and electromagnetic/acoustic wave propagation. There was no statistical element to my PhD, it was ...
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0answers
60 views

Named Entity Recognition using context of the sentence

I have a problem in which I want to know how can we extract or name the entity based on the context in which it is getting used in a sentence. For example: If we have to extract date field which is ...
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0answers
12 views

Speeding up actor critic training

I'm simulating a very simple system, recommendation system, and I am running an actor-critic model to predict what item I should recommend next. The agent is learning and is doing just fine. However, ...
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0answers
16 views

CNN: Should I include null examples in the training set for image segmentation

I am new to CNNs and was trying to use the Spacenet Building footprints data for some semantic image segmentation. However, in looking at the training images I found that a large number of images have ...
2
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1answer
42 views

problem of entry format for a simple model in Keras

I apologize if this question is too elementary for this site. I am new in learning Keras and Tensorflow and I have the following type/shape problem on which I have already wasted too much time. I ...
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0answers
32 views

Implementation of NLP to categorize text into two categories

I can't discuss my actual dataset, so please bear with me. Let's say I have a dataset that contains a population of 20,000 examinations by a school principal. The principal is to record their ...
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1answer
21 views

Neural Network Classification Probelm

How can 2-layer networks be used to classify more than two categories? I think, Just by adding more Units/Nodes into the existing layers? Thanks
4
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1answer
38 views

What does it mean to take the “average” of two decision trees by 'voting'

I have heard, in relation to random forest algorithm, that the algorithm will fit many decision trees and take the average of them by votes. (This is related to bagging as well) I understand what ...
1
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1answer
28 views

Neural network back propagation gradient descent calculus

So I've drawn a neural network diagram below: where $x_1, x_2,\ldots,x_m$ are the input layer, $h_1, h_2$ are the hidden layer and $\hat y_1, \hat y_2,\ldots \hat y_k$ are the output layer. In the $W^...
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1answer
40 views

Generalization bound (single hypothesis) in “Foundations of Machine Learning”

I have a question about Corollary $2.2$: Generalization bound--single hypothesis in the book "Foundations of Machine Learning" Mohri et al. $2012$. Equation $2.17$ seems to only hold when $\hat{R}_S(...
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1answer
22 views

Gradient descent with infinite gradient value

Given a function $f(x)$ and $\frac{\partial f(x)}{\partial x_i}=\frac{f^2(x1,...,x_i+\pi/2,...,x_n)-f^2(x1,...,x_i-\pi/2,...,x_n)}{f(x)}$. When $f(x)\to0$, $\frac{\partial f(x)}{\partial x_i}$ could ...
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2answers
33 views

How to compute f1 in tensorflow

I have code that computes the accuracy, but now I would like to compute the f1 score. ...
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0answers
15 views

Is the Apriori algorithm suitable for database tuples?

Problem description: I need to use an association rule algorithm that lets me use database tuples and I think Apriori is a good option, but I am not sure. Starting point: I know the Apriori ...
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1answer
22 views

Error: ValueError('%r cannot be used to seed a numpy.random.RandomState')

I am getting this error message while trying to fit a model for the isolationForest algorithm. ...
0
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1answer
16 views

Date transformation for KNN to get distance [duplicate]

I have data set with date features like 01/01/2019 and I would like to use KNN. However, I cannot find a good transformation for dates that has a meaningful distance result for the last feature. For ...
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1answer
25 views

Date transformation for KNN

I have data set with date features like 01/01/2019 and I would like to use KNN. However, I cannot find a good transformation for dates that has a meaningful ...
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0answers
20 views

Transpose-CNN with batch normalization

I am new to GAN (generative adversarial networks) and am trying to implement a Transpose-CNN (T-CNN) in Matlab (which is used as the generator in the GAN). I was able to build a Transpose-CNN with ...
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1answer
43 views

What should I observe when choosing which optimizer suits my Deep Neural Network model?

I have trained my neural network model with optimizers such as RMSProp, AdaGrad, Momentum, and Adam. Currently, after running the code, I have printed out the Train and Test Accuracy of every epoch (...
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0answers
24 views

Multi-label text classification (3 targetted result columns)

I am trying to build a multi-label text classifier for suggesting "AC_location", "Issue" and "Part_Affected" on the generated events. The textual data is full of ...
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2answers
52 views

CNN output shape explanation

I have the following sequential model: ...
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0answers
25 views

What causes the network validation loss to always be lower than train loss?

I am using a LSTM model to predict values in a time-series based network. However, my problem is that every time, I get consistently the validation loss lower than the training loss. Even at the ...
1
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1answer
15 views

Choosing the first node in a decision tree, basic example

I'm wondering whether I'm understanding the process of choosing a node correctly and would like to see if this example makes sense. using the following data : ...
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0answers
18 views

CNN binary classifier: validation accuracy fluctuation

For a (binary) classification problem, I made a CNN which works pretty fine. However, to be sure there are no bugs in the data preparation and such, I also trained my network on observations that ...
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2answers
45 views

Is there any clustering algorithm to find longest continuous subsequences?

I have data which contains access duration of some items. Example: t0~t5 is the access time duration, 1 means the items was accessed in the time duration, 0 means it wasn't. ...
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2answers
29 views

Detection model - Training with class-instance limit-awareness

Is there a way to make a detection model aware of the maximal number of possible objects of a given class within a single image? For example in a toy case with 2 classes. If I know that in every ...
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0answers
12 views

Is reward accumulated during a play iteration when performing SARSA?

I've been having issue with getting my DQN to converge to a good solution for snake. Regardless of the different types of reward functions I've tried, it seems that the snake is indefinitely going ...
1
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1answer
15 views

Integrate remote sensing & GIS data in a CNN

I am trying to develop a CNN model that takes as input a set of parameters derived from satellite imagery. What are the necessary steps to go through in order to make the Geotiff data acceptable as a ...
2
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1answer
63 views

Why does all of NLP literature use Noise contrastive estimation loss for negative sampling instead of sampled softmax loss?

A sampled softmax function is like a regular softmax but randomly selects a given number of 'negative' samples. This is difference than NCE Loss, which doesn't use a softmax at all, it uses a ...
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0answers
19 views

When should embeddings not be used for categorical data? What are their limitations?

I recently came across the concept of embeddings so the concept is still new to me, but it is my understanding that embeddings convert one-hot encoded input data into a dense vector. Vectors ...
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2answers
51 views

Why can decision trees have a high amount of variance

I've heard that decision trees can have a high amount of variance, and that for a data set $D$ split into test/train the decision tree could be quite different depending on how the data was split. ...
0
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1answer
29 views

Machine learning algorithm that can use many instances to predict 1 continuous outcome per person

I am trying to use movements identified from accelerometers during sleep to predict gait speed (continuous). I am trying to figure out what the best machine learning algorithms/ feature extraction ...
0
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1answer
19 views

Multiple regression (using machine learning - how plot data)

I wonder how I can use machine learning to plot multiple linear regression in a figure. I have one independent variable (prices of apartments) and five independent (floor, builtyear, roomnumber, ...
2
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1answer
28 views

Python - Create many dummy variables from one text variable?

I'm trying to create dummy variables for a variable that has text data in rows. Data in 1st row is: ...
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0answers
16 views

looping program for MLP Keras prediction [migrated]

I am (sort of a beginner starting out) experimenting with Keras on a time series data application where I created a regression model and then saved it to run on a different Python script. The time ...
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0answers
38 views

Financial SEC Filling Table data Extraction Using Machine Learning

I am trying to build a ML system which extracts financial data from Tables. Sample table is like below. From the above image you can see Net sales is an attribute along with two values 2707.1 and ...
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0answers
16 views

How do I train Xgboost classifier for ECG Signal data?

I am testing https://www.physionet.org/challenge/2017/sources/ submission. I like one of the submission code, which use Xgboost to train the classifier. Training ...