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Loss Function for Probability Regression

I am trying to predict a probability with a neural network, but having trouble figuring out which loss function is best. Cross entropy was my first thought, but other resources always talk about it in ...
ahbutfore's user avatar
  • 191
9 votes
0 answers
2k views

Why is my Keras model not learning image segmentation?

Edit: as is turns out, not even the model's initial creator could successfully fine-tune it. This is most likely a problem of implementation, or possibly related to the non-intuitive way in which the ...
Matt's user avatar
  • 199
9 votes
0 answers
3k views

Python : Feature Matching + Homography to find Multiple Objects

I'm trying to use OpenCV via Python to find multiple objects in a train image and match it with the key points detected from a query image. For my case, I'm trying to detect the tennis courts in the ...
Reward's user avatar
  • 91
9 votes
0 answers
2k views

AdaBoost implementation and tuning for high dimensional feature space in R

I am trying to implement the AdaBoost.M1 algorithm (trees as base-learners) to a data set with a large feature space (~ 20.000 features) and ~ 100 samples in R. ...
AfBM's user avatar
  • 91
8 votes
4 answers
5k views

How to perform feature selection on dataset with categorical and numerical features?

I am working on a dataset with 30 columns (29 numerical, 1 non-ordinal categorical). I hot-encoded the categorical feature and reached at 35 columns. To improve training efficiency, I want to perform ...
Songyu Yan's user avatar
8 votes
1 answer
1k views

Gensim LDA model: return keywords based on relevance (λ - lambda) value

I am using the gensim library for topic modeling, more specifically LDA. I created my corpus, my dictionary, and my LDA model. With the help of the pyLDAvis library I visualized the results. When I ...
Tasos Lytos's user avatar
8 votes
0 answers
138 views

Training value neural network AlphaGo style

I have been trying to replicate the results obtained by AlphaGo following their supervise learning protocol. The papers specify that they use a network that has two heads: a value head that predicts ...
Phaune's user avatar
  • 101
8 votes
3 answers
729 views

Chi-square as evaluation metrics for nonlinear machine learning regression models

I am using machine learning models to predict an ordinal variable (values: 1,2,3,4, and 5) using 7 different features. I posed this as a regression problem, so the final outputs of a model are ...
Alex's user avatar
  • 181
8 votes
1 answer
313 views

How to predict advantage value in deep reinforcement learning

I'm currently working on a collection of reinforcement algorithms: https://github.com/lhk/rl_gym For deep q-learning, you need to calculate the q-values that should be predicted by your network. There ...
lhk's user avatar
  • 181
8 votes
1 answer
4k views

Decision Trees - C4.5 vs CART - rule sets

When I read the scikit-learn user manual about Decision Trees, they mentioned that CART (Classification and Regression Trees) is very similar to C4.5, but it differs in that it supports numerical ...
emperorspride188's user avatar
7 votes
2 answers
132 views

Data transformations in hierarchical classification

I am building a hierarchical text classifier using the Local Classifier Per Parent Node (LCPN) approach with the 'siblings' policy as described in the A survey of hierarchical classification across ...
matentzn's user avatar
  • 171
7 votes
1 answer
9k views

How is WordPiece tokenization helpful to effectively deal with rare words problem in NLP?

I have seen that NLP models such as BERT utilize WordPiece for tokenization. In WordPiece, we split the tokens like playing to play and ##ing. It is mentioned that it covers a wider spectrum of Out-Of-...
Harman's user avatar
  • 706
7 votes
0 answers
3k views

Tensorflow v1 Dataset API AttributeError with ndim

I'd like to make pipeline for optimizing Gpu and Cpu. Dataset It's about 10000 datapoint and 4 description variables for the regression problem. ...
AutomaKen's user avatar
7 votes
0 answers
2k views

Using the Python Keras multi_gpu_model with LSTM / GRU to predict Timeseries data

I'm having an issue with python keras LSTM / GRU layers with multi_gpu_model for machine learning. When I use a single GPU, the predictions work correctly ...
Palisadoes's user avatar
7 votes
0 answers
1k views

Multivariate, multistep forecasting with LSTM

I want to use an RNN with LSTM to forecast multiple steps into the future, based on multiple inputs. I have some ideas for different ways to approach this, but I'm afraid I'm missing the "right way" ...
Aurast's user avatar
  • 171
7 votes
0 answers
2k views

Fine tuning accuracy lower than Raw Transfer Learning Accuracy

I've used transfer learning on Inception V3 with ImageNet weights on Keras with Tensorflow backend on python 2.7 to create an image classifier. I first extracted and saved the bottleneck features from ...
Varun's user avatar
  • 71
7 votes
0 answers
946 views

ALS in Spark: what loss function is it minimizing?

I’ve playing with the MovieLens ratings dataset under Spark’s ALS and a manual implementation of ALS and comparing results with the same hyperparameters. I’d like to know this exactly in order to make ...
anymous.asker's user avatar
7 votes
0 answers
516 views

differences between LSQR and FTRL when working with very sparse data

I have a 2M instances dataset with millions of very very sparse dummy variables created using the hashing trick = ...
ihadanny's user avatar
  • 1,357
7 votes
1 answer
379 views

When to use which multiple testing correction?

There are a large number multiple testing p-value correction methods. e.g.: ...
lordy's user avatar
  • 304
6 votes
2 answers
247 views

How sklearn SVM find the initial hyperplane before Optimisation?

The optimization goal of the SVM is to maximize the distance between the positive and negative hyperplanes. But before optimizing, how does sklearn first find the positive and negative support vectors ...
user3363813's user avatar
6 votes
3 answers
186 views

What Clustering Method Should I Use?

My data is a group of 10 thousand points (each having an node location (x,y)) that are spread across a plane. They are also chromatically-colored based on their weight. I need to finalize a bayesian ...
ChessGrandMaster's user avatar
6 votes
2 answers
4k views

Triangle Pattern Recognition on Financial Market with Python

I'm working on a personal project to find Triangles on any stock in Python. I detect the max and min points (shift(-5,+5) because if I consider only shift(-1+1) I have a lot of lines) and write lines ...
Martin Bouhier's user avatar
6 votes
0 answers
150 views

Unable to transform (greatly performing) Autoencoder into Variational Autoencoder

Following the procedure described in this SO question, I am trying to transform my (greatly performing) convolutional Autoencoder into a Variational version of the same Autoencoder. As explained in ...
user87590's user avatar
6 votes
1 answer
8k views

Keras - Implementation of custom loss function with multiple outputs

I am trying to replicate (a way smaller version) the AlphaGo Zero system. However, in the network model, I am having a problem. The loss function I am supposed to implement is the following: $$l = (z -...
ihavenoidea's user avatar
6 votes
1 answer
282 views

What does big O mean in KNN optimal weights?

Wiki gives this definition of KNN In pattern recognition, the k-nearest neighbors algorithm (k-NN) is a non-parametric method used for classification and regression. In both cases, the input consists ...
JJJohn's user avatar
  • 623
6 votes
0 answers
337 views

Optimal implementation of vanilla DQN loss in Keras

I've implemented vanilla DQN for continuous/non-images (no CNN) states in keras. But, I'm not sure if my implementation of the loss computation is optimal. For reminder the loss is defined as : $loss=...
Johan Gras's user avatar
6 votes
0 answers
92 views

Fitting model to differenced time series

I have a time series on daily stock price of company(2013 data points).I took a first order difference and the following acf and pacf plots of the differenced series were obtained. However, I am ...
Jor_El's user avatar
  • 231
6 votes
2 answers
3k views

How to deal with missing data for Bernoulli Naive Bayes?

I am dealing with a dataset of categorical data that looks like this: ...
Chuck's user avatar
  • 161
6 votes
2 answers
2k views

Metrics to evaluate features' importance in classification problem (with random forest)

I want to evaluate the importance of each of the features of a 2000x60 dataset in a classification problem with random forest. The most widely used ones apparrently are: Cross Entropy-Information ...
Outcast's user avatar
  • 1,057
6 votes
2 answers
207 views

Gridsearch XGBoost for ensemble. Do I include first-level prediction matrix of base learners in train set?

I'm not quite sure how I should go about tuning xgboost before I use it as a meta-learner in ensemble learning. Should I include the prediction matrix (ie. df containing columns of prediction results ...
doyz's user avatar
  • 161
6 votes
1 answer
187 views

Predicting change of shapes/coordinates

I'm trying to find a way to predict/calculate how a shape (e.g. outline of a glacier) will change in the future—based on its history (previous shape) and additional factors (e.g. Δtemperature). In my ...
Fabian Schultz's user avatar
6 votes
1 answer
2k views

What is the minimum number of times a word needs to appear in word2vec training corpus for quality results?

When training a word2vec model with, eg, gensim, you can specify the minimum times a word needs to be seen (with the parameter min_count). The default value for this seems to be 5. Are there any ...
user1253952's user avatar
6 votes
0 answers
310 views

Confidence value in AdaBoost?

I read this introduction about AdaBoost (http://www.cs.man.ac.uk/~nikolaon/~nikolaon_files/Introduction_to_AdaBoost.pdf), and am curious why confidence for each model is defined as $$\alpha_j=\frac{...
user3326682's user avatar
6 votes
0 answers
379 views

Maths of Xavier initialization

The paper I read is Glorot et al (2010). And the math part is in Section 4.2.1. Formula (5) and (10) make sense to me but I cannot derive formula (6) and (7) myself from (2) and (3). I found many ...
Jason's user avatar
  • 61
6 votes
0 answers
99 views

Classify driver based on time-series sensor data

I want to build a model that can detect which driver is driving now the car based on a dataset that contains 20 driver records for 3600s each driver ( the dataset contains all the car sensors values ...
John Karimov's user avatar
6 votes
0 answers
152 views

Learning a logical function with a 2 layer BDN network - manual weight setting rule question?

So I am trying to construct a 2-layer network of binary decision neurons as proposed by McCullough and Pitts (1943) to learn a logical function (a composition of AND's and OR's) such as: $((\neg x_1\...
David Silver's user avatar
6 votes
0 answers
612 views

Adversarial Learning for Semantic Segmentation

I am incorporating Adversarial Training for Semantic Segmentation from Adversarial Learning for Semi-Supervised Semantic Segmentation. The idea is like this: The discriminator takes as input a ...
ethelion's user avatar
6 votes
0 answers
233 views

Connect output node to next hidden node in RNN

I'm trying to build a neural network with an unconventional architecture and a having trouble figuring out how. Usually we have connections like so, where $X=$ input, $H=$ hidden layer, $Y=$ output ...
tom's user avatar
  • 2,248
6 votes
0 answers
3k views

How to tune weights in Voting Classifier (Sklearn)

I am trying to do the following: ...
Abhinav Gupta's user avatar
6 votes
0 answers
1k views

Keras objective function shared between outputs

Is there any way to implement a loss function that is shared between outputs? I have a 2D image output and scalar classification that are both used by a single loss function. I have attempted writing ...
Daniel Underwood's user avatar
6 votes
0 answers
112 views

Fixed-radius range search in non-Euclidean space

I'm trying to find an indexing data structure most suitable for my metric space: set of IP network related data (IP addresses, ports, TCP flags, ...), distance function is continuous, non-Euclidean ...
Jan Wrona's user avatar
6 votes
0 answers
12k views

Tuning Gradient Boosted Classifier's hyperparametrs and balancing it

I am not sure if it is a correct stack. Maybe I should have put my question into crossvalidated. Nevertheless, I perform following steps to tune the hyperparameters for a gradient boosting model: ...
user1877600's user avatar
6 votes
0 answers
291 views

how to propagate error from convolutional layer to previous layer?

I've been trying to implement a simple convolutional neural network. But I've been stuck at this problem for over a week. To be specific, assume there are 3 layers in a convolutional pass, marked as ...
Shindou's user avatar
  • 161
6 votes
0 answers
102 views

Meta-analysis of public 16S data

I am trying to start a meta-analysis for which I want to extract some 16S-based information from public databases. Moreover, I want to relate this information with any metadata found in the associated ...
André Soares's user avatar
6 votes
1 answer
488 views

Visualizing large number of points as a 3D density map

The result of my computational simulation is a (time-dependent) system of large number (~100k) of moving points in a confined space. Each point has its own Cartesian coordinates as well as a weight (...
deeep's user avatar
  • 61
6 votes
0 answers
390 views

3D map using leaflet

I'm trying to create 3D bars on this map. Can anyone please advise if this is possible, and how? http://leafletjs.com/examples/choropleth.html My data: UFO sightings in the USA (location wise). ...
Minu's user avatar
  • 805
6 votes
3 answers
332 views

Anomaly detection using clustering of highly correlated Categorical data

My data has two columns and both are highly correlated e.g. if column1 has value ABC, column2 should be XYZ i.e. ABC-->XYZ. If column2 has anything else it's Anomaly. Likewise, there are thousands ...
viral kapadia's user avatar
6 votes
1 answer
4k views

How does XGBoost compute the probabilities in predict_proba()?

I'm using the sklearn wrapper for XGBoost. I didn't manage to find a clear explanation for the way the probabilities given as output by predict_proba() are computed....
keren42's user avatar
  • 61
5 votes
1 answer
2k views

Difference Between Attention and Fully Connected Layers in Deep Learning

There have been several papers in the last few years on the so-called "Attention" mechanism in deep learning (e.g. 1 2). The concept seems to be that we want the neural network to focus on ...
Adam's user avatar
  • 896
5 votes
0 answers
87 views

How is image convolution actually implemented in deep learning libraries using simple linear algebra?

As a clarifier, I want to implement cross-correlation, but the machine learning literature keeps referring to it as convolution so I will stick with it. I am trying to implement image convolution ...
Jozef Nagy's user avatar

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