Evolutionary Systems
Scalable Prototype Selection by Genetic Algorithms and Hashing
Plasencia-Calaña, Yenisel, Orozco-Alzate, Mauricio, Méndez-Vázquez, Heydi, García-Reyes, Edel, Duin, Robert P. W.
Classification in the dissimilarity space has become a very active research area since it provides a possibility to learn from data given in the form of pairwise non-metric dissimilarities, which otherwise would be difficult to cope with. The selection of prototypes is a key step for the further creation of the space. However, despite previous efforts to find good prototypes, how to select the best representation set remains an open issue. In this paper we proposed scalable methods to select the set of prototypes out of very large datasets. The methods are based on genetic algorithms, dissimilarity-based hashing, and two different unsupervised and supervised scalable criteria. The unsupervised criterion is based on the Minimum Spanning Tree of the graph created by the prototypes as nodes and the dissimilarities as edges. The supervised criterion is based on counting matching labels of objects and their closest prototypes. The suitability of these type of algorithms is analyzed for the specific case of dissimilarity representations. The experimental results showed that the methods select good prototypes taking advantage of the large datasets, and they do so at low runtimes. Preprint submitted to Elsevier December 27, 2017 1. Introduction The vector space representation is a common option to represent the data for learning tasks since many statistical techniques are applicable for this kind of representation. However, there is an increasing number of real-world problems which are not vectorial. Instead, the data are given in terms of pairwise dissimilarities which may be non-Euclidean and even non-metric.
Profit Driven Decision Trees for Churn Prediction
Höppner, Sebastiaan, Stripling, Eugen, Baesens, Bart, Broucke, Seppe vanden, Verdonck, Tim
Customer retention campaigns increasingly rely on predictive models to detect potential churners in a vast customer base. From the perspective of machine learning, the task of predicting customer churn can be presented as a binary classification problem. Using data on historic behavior, classification algorithms are built with the purpose of accurately predicting the probability of a customer defecting. The predictive churn models are then commonly selected based on accuracy related performance measures such as the area under the ROC curve (AUC). However, these models are often not well aligned with the core business requirement of profit maximization, in the sense that, the models fail to take into account not only misclassification costs, but also the benefits originating from a correct classification. Therefore, the aim is to construct churn prediction models that are profitable and preferably interpretable too. The recently developed expected maximum profit measure for customer churn (EMPC) has been proposed in order to select the most profitable churn model. We present a new classifier that integrates the EMPC metric directly into the model construction. Our technique, called ProfTree, uses an evolutionary algorithm for learning profit driven decision trees. In a benchmark study with real-life data sets from various telecommunication service providers, we show that ProfTree achieves significant profit improvements compared to classic accuracy driven tree-based methods.
Natural selection is still at work in humans, study finds
Humans aren't quite done evolving, a dramatic new study has found. Researchers analyzing genetic and health data on hundreds of thousands of people, uncovered evidence to suggest natural selection has an ongoing, albeit small, effect on modern humans. The new study appears to be favour larger, 'hunkier' men with a greater body mass index, and younger mothers. A new study found that natural selection appears to favour women who get a young start on having a family. Researchers examined data from the UK Biobank, looking at genetic variants and their correlation to the number of children people had.
overnewser, The best real-time news sites information.
In this contributed article, Sharmistha Sarkar of India based Progressive Markets, highlights a handful of compelling technology advancements that are helping to drive the evolution of artificial intelligence. Industry is expected to grow at a CAGR of 46.5% from 2017 to 2025. The market is growing fast due to improved productivity through AI, its diversified application areas, and big data integration drive....
Machine learning is not just for the buy side - Risk.net
The most common application being researched for machine learning is optimal execution. When large trades are executed in the market, it could potentially push prices in an unfavourable direction, so it makes sense that traders are keen on optimising this cost. So far, most of the interest in applying machine learning technology to reduce trading costs has been from the buy side. However, recent research by quants from Standard Chartered shows this may be about to change. In this month's first technical, Evolutionary algos for optimising MVA, Alexei Kondratyev, a managing director at Standard Chartered in London, and George Giorgidze a senior quantitative developer in the strats team within the same bank, propose machine learning techniques to optimise initial margin costs through trade selection.
Highly Efficient Human Action Recognition with Quantum Genetic Algorithm Optimized Support Vector Machine
Liu, Yafeng, Feng, Shimin, Zhao, Zhikai, Ding, Enjie
In this paper we propose the use of quantum genetic algorithm to optimize the support vector machine (SVM) for human action recognition. The Microsoft Kinect sensor can be used for skeleton tracking, which provides the joints' position data. However, how to extract the motion features for representing the dynamics of a human skeleton is still a challenge due to the complexity of human motion. We present a highly efficient features extraction method for action classification, that is, using the joint angles to represent a human skeleton and calculating the variance of each angle during an action time window. Using the proposed representation, we compared the human action classification accuracy of two approaches, including the optimized SVM based on quantum genetic algorithm and the conventional SVM with grid search. Experimental results on the MSR-12 dataset show that the conventional SVM achieved an accuracy of $ 93.85\% $. The proposed approach outperforms the conventional method with an accuracy of $ 96.15\% $.
Evolving Spatially Aggregated Features from Satellite Imagery for Regional Modeling
Kriegman, Sam, Szubert, Marcin, Bongard, Josh C., Skalka, Christian
Satellite imagery and remote sensing provide explanatory variables at relatively high resolutions for modeling geospatial phenomena, yet regional summaries are often desirable for analysis and actionable insight. In this paper, we propose a novel method of inducing spatial aggregations as a component of the machine learning process, yielding regional model features whose construction is driven by model prediction performance rather than prior assumptions. Our results demonstrate that Genetic Programming is particularly well suited to this type of feature construction because it can automatically synthesize appropriate aggregations, as well as better incorporate them into predictive models compared to other regression methods we tested. In our experiments we consider a specific problem instance and real-world dataset relevant to predicting snow properties in high-mountain Asia.
Scalable Co-Optimization of Morphology and Control in Embodied Machines
Cheney, Nick, Bongard, Josh, SunSpiral, Vytas, Lipson, Hod
Evolution sculpts both the body plans and nervous systems of agents together over time. In contrast, in AI and robotics, a robot's body plan is usually designed by hand, and control policies are then optimized for that fixed design. The task of simultaneously co-optimizing the morphology and controller of an embodied robot has remained a challenge. In psychology, the theory of embodied cognition posits that behavior arises from a close coupling between body plan and sensorimotor control, which suggests why co-optimizing these two subsystems is so difficult: most evolutionary changes to morphology tend to adversely impact sensorimotor control, leading to an overall decrease in behavioral performance. Here, we further examine this hypothesis and demonstrate a technique for "morphological innovation protection", which temporarily reduces selection pressure on recently morphologically-changed individuals, thus enabling evolution some time to "readapt" to the new morphology with subsequent control policy mutations. We show the potential for this method to avoid local optima and converge to similar highly fit morphologies across widely varying initial conditions, while sustaining fitness improvements further into optimization. While this technique is admittedly only the first of many steps that must be taken to achieve scalable optimization of embodied machines, we hope that theoretical insight into the cause of evolutionary stagnation in current methods will help to enable the automation of robot design and behavioral training -- while simultaneously providing a testbed to investigate the theory of embodied cognition.
Evolutionary Algorithms for Feature Selection
Feature selection is a very important technique in machine learning.We need to be able to solve it to produce models. Feature Selection requires heuristic processes to find an optimal machine learning subset. In the previous post we discussed the brute force algorithm as well as forward selection and backward elimination which were both not a great fit. What other options are there? We can use one of the most common optimization algorithms for multi-modal fitness landscapes: evolutionary algorithms. Evolutionary algorithm is a generic optimization technique mimicking the ideas of natural evolution.