Previously we have tried to run weka server to utilize all cores of the processor in classification tasks. But it appears that weka server works only in explorer for classification routines. For more advanced machine learning there is a more flexible tool – experimenter. Weka server doesn’s support this area. So what to do if you want more performance or utilize multi-core processor of the local machine. There is a way out, but it is quite tricky. Weka has the ability to perform remote experiments that allow spreading the load across multiple host machines that have Weka set up. You can read the documentation of remote experiment on Weka wikispaces, but in some cases, it may be somewhat confusing. It took time for me to figure out some parts by trial and error. The trickiest part is to set everything up and prepare the necessary command to be run before performing a remote experiment. So let’s get to it.
Currently, WEKA is one of the most favorites machine learning tools. Without programming skills, you can do serious classification, clustering, and big data analysis. For some time I’ve been using its standard GUI features without thinking much about performance bottlenecks. But since researches are becoming more complex by using ensemble, voting and other meta-algorithms that generally are based on multiple classifiers running simultaneously, the performance issues start becoming annoying. You need to wait for hours until the task is completed. The problem is that when running classification algorithms from the WEKA GUI, the utilize a single core of your processor. Such algorithms as Multi-layer Percepron running 10 fold cross-validation is calculating one cross fold at the time on one core taking a long time to accomplish: So I started looking for options to make it use all cores of the processor as separate threads for each fold of operation. There are a couple of options available to do so. One is to use WekaServer package, and another is remote host processing. This time we will focus on WekaServer solution. The idea is to start a WEKA server as a distributed execution environment. When starting the server, you can indicate how…
Logistic regression is the next step from linear regression. The most real-life data have a non-linear relationship, thus applying linear models might be ineffective. Logistic regression is capable of handling non-linear effects in prediction tasks. You can think of lots of different scenarios where logistic regression could be applied. There can be financial, demographic, health, weather and other data where the model could be implemented and used to predict next events on future data. For instance, you can classify emails into spam and non-spam, transactions being fraud or not, tumors being malignant or benign. In order to understand logistic regression, let’s cover some basics, do a simple classification on data set with two features and then test it on real-life data with multiple features.
Artificial Intelligence (AI) is the field of computer science which uses mechanical and computational processes to echo almost all aspects of human intelligence. AI can perform multiple functions: sensory interaction with the environment and the ability to make decisions about events that haven’t happened yet without any human assistance whatsoever. Targeted advertising and virtual agents that recognize the patterns of your behavior are much standards in today’s online undertakings. Artificial Intelligence is used by business enterprises in data analysis algorithms which have the highest advantage of analyzing the Big Data, and it also involves customer engaging techniques. Apart from IBM which developed some of the earliest functions of AI, Google and Facebook are also using AI for the analytic purpose of the massive amount of data they receive.
This is a followup post from previous where we were calculating Naive Bayes prediction on the given data set. This time I want to demonstrate how all this can be implemented using WEKA application. For those who don’t know what WEKA is I highly recommend visiting their website and getting the latest release. It is a compelling machine learning software written in Java. You can find plenty of tutorials on youtube on how to get started with WEKA. So I won’t get into details. I’m sure you’ll be able to follow anyway.
Probably you’ve heard about Naive Bayes classifier and likely used in some GUI based classifiers like WEKA package. This is a number one algorithm used to see the initial results of classification. Sometimes surprisingly it outperforms the other models with speed, accuracy and simplicity. Lets see how this algorithm looks and what does it do. As you may know algorithm works on Bayes theorem of probability which allows to predict the class of unknown data set. Hoe you are comfortable with probability math – at least some basics.
Single feature linear regression is simple. All you need is to find a function that fits training data best. It is also easy to plot data and learning curve. But in reality regression analysis is based on multiple features. So in most cases, we cannot imagine the multidimensional space where data could be plotted. We need to rely on the methods we use. You have to feel comfortable with linear algebra where matrices and vectors are used. If previously we had one feature (temperature) now we need to introduce more of them. So we need to expand hypothesis to accept more features. From now and later on instead of output y we are going to use h(x) notation: As you can see with more variables (features), we also end up with more parameters θ that has to be learned. Before we move let’s find suitable data that we could use for building machine learning algorithm. The data set Again we are going to use data set college cengage. This time we select health data set with several variables. The data (X1, X2, X3, X4, X5) are by city. X1 = death rate per 1000 residents X2 = doctor availability per…