anomaly-detection | simple demonstration of sub-sequence sampling | Machine Learning library
kandi X-RAY | anomaly-detection Summary
kandi X-RAY | anomaly-detection Summary
This project provides a demonstration of a simple time-series anomaly detector. The idea is to use sub-sequence clustering of an EKG signal to reconstruct the EKG. The difference between the original and the reconstruction can be used as a measure of how much like the signal is like a prototypical EKG. Poor reconstruction can thus be used to find anomalies in the original signal. The data for this demo are taken from physionet. See The particular data used for this demo is the Apnea ECG database which can be found at. All necessary data for this demo is included as a resource in the source code (see src/main/resources/a02.dat). You can find original version of the training data at. This file is 6.1MB in size and contains several hours of recorded EKG data from a patient in a sleep apnea study. This file contains 3.2 million samples of which we use the first 200,000 for training.
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- Runs a test program
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- Read a matrix from an input stream
anomaly-detection Key Features
anomaly-detection Examples and Code Snippets
Community Discussions
Trending Discussions on anomaly-detection
QUESTION
Please consider this records:
...ANSWER
Answered 2022-Apr-05 at 10:08When you calculate the AVG & STDEV simply group by the Type.
Then join the data to the summary on the Type.
QUESTION
I looked into the anomaly detection using both PCA and Autoencoder using the codes from the following link: Machine learning for anomaly detection and condition monitoring and I try to run the code part for using PCA with Mahalanobis Distance, however, if I run the code I always get the exception message and it turns out the problem is with the covariance matrix function part where the error 'numpy.ndarray' object is not callable
appears. I tried to create new variables, change the dataframe into NumPy but nothing worked what is causing this error?
Code:
...ANSWER
Answered 2021-Sep-27 at 12:35Per your comment, you have a namespace collision between a var cov_matrix
and a function cov_matrix()
Change that line to e.g.
QUESTION
I have recently transitioned from R to python, and I am not sure how to problem solve the following.
When I run the setup for pycaret anomaly detection, following the instructions that can be found here, on my own data I get the following error.
...ANSWER
Answered 2021-Sep-09 at 12:22The answer to this question is that the environment had a library versions such as numpy
that were too new for pycaret
to work with, for example, pycaret need numpy (1.19.5 and will not work with newer).
My solution was to create a new environment in anaconda, which used pip install pycaret[full]
, and added nothing else to the environment. It worked after this.
QUESTION
While learning Azure Log processing I started recording simple queue counts as metrics via AppInsight. Currently I process them in a fairly simple way and show them in a same graph.
The simple query is like
...ANSWER
Answered 2021-Apr-19 at 07:02- If you have both the actual counts and the forecast in the table then 'render timechart shows both. Note that you need to specify to max_t+horizon in make-series.
QUESTION
I need to automatically extract raw data of a PowerBI visualisation across multiple published reports.
Why not just pull the underlying dataset? Because the visualisations are using anomaly detection features of PowerBI, which include anomaly flags not available in the underlying dataset (basically, the visualisations contain calculated columns that are not included in main PowerBI data model)
Ideally a REST API solution would be best, but dumping CSV files or other more roundabout methods are ok.
So far, the closest functionality I can see is in the Javascript API here - https://docs.microsoft.com/en-us/javascript/api/overview/powerbi/export-data, which allows a website to communicate with an embedded PowerBI report and pass in and out information. But this doesn't seem to match my implementation needs.
I have also seen this https://docs.microsoft.com/en-us/azure/cognitive-services/anomaly-detector/tutorials/batch-anomaly-detection-powerbi which is to manually implement anomaly detection via Azure Services rather than the native PowerBI functionality, however this means abandoning the simplicity of the PowerBI anomaly function that is so attractive in the first place.
I have also seen this StackOverflow question here PowerBI Report Export in csv format via Rest API and it mentions using XMLA endpoints, however it doesn't seem like the client applications have the functionality to connect to visualisations - for example I tried DAX Studio and it doesn't seem to have any ability to query the data on a visualisation level.
...ANSWER
Answered 2021-Apr-19 at 04:32I'm afraid all information on PowerBI says this is not possible. The API only supports PDF, PPTX and PNG options, and as such the integration with Power Automate doesn't do any better.
The StackOverflow question you link has some information on retrieving the Dataset but that's before the anomaly detection has processed the data.
I'm afraid your best bet is to, indeed, use the Azure service. I'd suggest ditching PowerBI and going to an ETL tool like DataFactory or even into the AzureML propositions Microsoft offers. You'll be more flexible than in PowerBI as well since you'll have the full power of Python/R notebooks at your disposal.
Sorry I can't give you a better answer.
QUESTION
I am following this tutorial to create a Keras-based autoencoder, but using my own data. That dataset includes about 20k training and about 4k validation images. All of them are very similar, all show the very same object. I haven't modified the Keras model layout from the tutorial, only changed the input size, since I used 300x300 images. So my model looks like this:
...ANSWER
Answered 2021-Apr-05 at 15:32It could be that the decay_rate
argument in tf.keras.optimizers.schedules.ExponentialDecay is decaying your learning rate quicker than you think it is, effectively making your learning rate zero.
QUESTION
I am reading this tutorial in order to create my own autoencoder based on Keras. I followed the tutorial step by step, the only difference is that I want to train the model using my own images data set. So I changed/added the following code:
...ANSWER
Answered 2021-Mar-30 at 15:25Use class_mode="input" at the flow_from_directory so returned Y will be same as X
class_mode: One of "categorical", "binary", "sparse", "input", or None. Default: "categorical". Determines the type of label arrays that are returned: - "categorical" will be 2D one-hot encoded labels, - "binary" will be 1D binary labels, "sparse" will be 1D integer labels, - "input" will be images identical to input images (mainly used to work with autoencoders). - If None, no labels are returned (the generator will only yield batches of image data, which is useful to use with
model.predict()
). Please note that in case of class_mode None, the data still needs to reside in a subdirectory ofdirectory
for it to work correctly.
Code should end up like:
QUESTION
My question lies specifically in knn method in Anomaly Detection module of pycaret library. Usually number of k neighbors has to be specified. Like for example in PyOD library.
How to learn what number of neighbors knn uses in pycaret library? Or does it have a default value?
...ANSWER
Answered 2021-Jan-06 at 03:17you can find the number of neighbors of the constructed knn model by printing it.
By default, n_neighbors=5, radius=1.0
.
I run the knn demo code locally, with:
QUESTION
Here mydata
...ANSWER
Answered 2020-Dec-22 at 19:44The time_decompose()
function requires data in the form of:
A tibble or tbl_time object
(from ?time_decompose
)
Perhaps zem
is a data.frame? You can include as_tibble()
in the pipe to make sure it is a tibble ahead of time.
In addition, it expects to work on time based data:
It is designed to work with time-based data, and as such must have a column that contains date or datetime information.
I added to your test data a column with dates. Here is a working example:
QUESTION
Specifically what spurred this question is the return_sequence
argument of TensorFlow's version of an LSTM layer.
The docs say:
Boolean. Whether to return the last output. in the output sequence, or the full sequence. Default: False.
I've seen some implementations, especially autoencoders that use this argument to strip everything but the last element in the output sequence as the output of the 'encoder' half of the autoencoder.
Below are three different implementations. I'd like to understand the reasons behind the differences, as the seem like very large differences but all call themselves the same thing.
Example 1 (TensorFlow):This implementation strips away all outputs of the LSTM except the last element of the sequence, and then repeats that element some number of times to reconstruct the sequence:
...ANSWER
Answered 2020-Dec-08 at 15:43There is no official or correct way of designing the architecture of an LSTM based autoencoder... The only specifics the name provides is that the model should be an Autoencoder and that it should use an LSTM layer somewhere.
The implementations you found are each different and unique on their own even though they could be used for the same task.
Let's describe them:
TF implementation:
- It assumes the input has only one channel, meaning that each element in the sequence is just a number and that this is already preprocessed.
- The default behaviour of the
LSTM layer
in Keras/TF is to output only the last output of the LSTM, you could set it to output all the output steps with thereturn_sequences
parameter. - In this case the input data has been shrank to
(batch_size, LSTM_units)
- Consider that the last output of an LSTM is of course a function of the previous outputs (specifically if it is a stateful LSTM)
- It applies a
Dense(1)
in the last layer in order to get the same shape as the input.
PyTorch 1:
- They apply an embedding to the input before it is fed to the LSTM.
- This is standard practice and it helps for example to transform each input element to a vector form (see word2vec for example where in a text sequence, each word that isn't a vector is mapped into a vector space). It is only a preprocessing step so that the data has a more meaningful form.
- This does not defeat the idea of the LSTM autoencoder, because the embedding is applied independently to each element of the input sequence, so it is not encoded when it enters the LSTM layer.
PyTorch 2:
- In this case the input shape is not
(seq_len, 1)
as in the first TF example, so the decoder doesn't need a dense after. The author used a number of units in the LSTM layer equal to the input shape.
- In this case the input shape is not
In the end you choose the architecture of your model depending on the data you want to train on, specifically: the nature (text, audio, images), the input shape, the amount of data you have and so on...
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Install anomaly-detection
You can use anomaly-detection like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the anomaly-detection component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer maven.apache.org. For Gradle installation, please refer gradle.org .
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