LIBSVM: A library for support vector machines

doi:10.1145/1961189.1961199

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LIBSVM: A library for support vector machines

Journal Article•DOI•

LIBSVM: A library for support vector machines

Chih-Chung Chang¹, Chih-Jen Lin¹•Institutions (1)

National Taiwan University¹

06 May 2011-ACM Transactions on Intelligent Systems and Technology (ACM)-Vol. 2, Iss: 3, pp 27

TL;DR: Issues such as solving SVM optimization problems theoretical convergence multiclass classification probability estimates and parameter selection are discussed in detail.

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Abstract: LIBSVM is a library for Support Vector Machines (SVMs). We have been actively developing this package since the year 2000. The goal is to help users to easily apply SVM to their applications. LIBSVM has gained wide popularity in machine learning and many other areas. In this article, we present all implementation details of LIBSVM. Issues such as solving SVM optimization problems theoretical convergence multiclass classification probability estimates and parameter selection are discussed in detail.

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Journal Article•DOI•

Control of a humanoid robot by a noninvasive brain–computer interface in humans

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Christian J. Bell¹, Pradeep Shenoy¹, Rawichote Chalodhorn¹, Rajesh P. N. Rao¹•Institutions (1)

University of Washington¹

15 May 2008-Journal of Neural Engineering

TL;DR: It is shown that by leveraging advances in robotics, an interface based on EEG can be used to command a partially autonomous humanoid robot to perform complex tasks such as walking to specific locations and picking up desired objects.

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Abstract: We describe a brain-computer interface for controlling a humanoid robot directly using brain signals obtained non-invasively from the scalp through electroencephalography (EEG). EEG has previously been used for tasks such as controlling a cursor and spelling a word, but it has been regarded as an unlikely candidate for more complex forms of control owing to its low signal-to-noise ratio. Here we show that by leveraging advances in robotics, an interface based on EEG can be used to command a partially autonomous humanoid robot to perform complex tasks such as walking to specific locations and picking up desired objects. Visual feedback from the robot's cameras allows the user to select arbitrary objects in the environment for pick-up and transport to chosen locations. Results from a study involving nine users indicate that a command for the robot can be selected from four possible choices in 5 s with 95% accuracy. Our results demonstrate that an EEG-based brain-computer interface can be used for sophisticated robotic interaction with the environment, involving not only navigation as in previous applications but also manipulation and transport of objects.

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388 citations

Journal Article•

Affective e-Learning: Using "Emotional" Data to Improve Learning in Pervasive Learning Environment

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Liping Shen, Minjuan Wang, Ruimin Shen

01 Apr 2009-Educational Technology & Society

TL;DR: An experimental prototype of the affective e-Learning model was built to help improveStudents’ learning experience by customizing learning material delivery based on students’ emotional state and indicated the superiority of emotion aware over non-emotion-aware with a performance increase of 91%.

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Abstract: Using emotion detection technologies from biophysical signals, this study explored how emotion evolves during learning process and how emotion feedback could be used to improve learning experiences. This article also described a cutting-edge pervasive e-Learning platform used in a Shanghai online college and proposed an affective e-Learning model, which combined learners’ emotions with the Shanghai e-Learning platform. The study was guided by Russell’s circumplex model of affect and Kort’s learning spiral model. The results about emotion recognition from physiological signals achieved a best-case accuracy (86.3%) for four types of learning emotions. And results from emotion revolution study showed that engagement and confusion were the most important and frequently occurred emotions in learning, which is consistent with the findings from AutoTutor project. No evidence from this study validated Kort’s learning spiral model. An experimental prototype of the affective e-Learning model was built to help improve students’ learning experience by customizing learning material delivery based on students’ emotional state. Experiments indicated the superiority of emotion aware over non-emotion-aware with a performance increase of 91%.

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387 citations

Cites methods from "LIBSVM: A library for support vecto..."

...The best recognition rate 86.3% was achieved by LIBSVM tested on data set I, that is, the data set of one sample every one second....
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...The two pattern classification methods: LIBSVM and KNN were tested over the two data sets....
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...By using the software LIBSVM (Chang & Lin, 2007), we first found the best parameter C andγ with crossvalidation, then used the best parameter C and γ to train the whole training set, and finally tested over the testing set....
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Journal Article•DOI•

Greek long-term energy consumption prediction using artificial neural networks

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Lambros Ekonomou¹•Institutions (1)

School of Pedagogical and Technological Education¹

01 Feb 2010-Energy

TL;DR: The proposed approach can be useful in the effective implementation of energy policies, since accurate predictions of energy consumption affect the capital investment, the environmental quality, the revenue analysis, the market research management, while conserve at the same time the supply security.

...read moreread less

386 citations

Journal Article•DOI•

Hand Gesture Recognition in Real-Time for Automotive Interfaces: A Multimodal Vision-based Approach and Evaluations

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Eshed Ohn-Bar¹, Mohan M. Trivedi¹•Institutions (1)

University of California, San Diego¹

26 Aug 2014-IEEE Transactions on Intelligent Transportation Systems

TL;DR: A vision-based system that employs a combined RGB and depth descriptor to classify hand gestures and is studied for a human-machine interface application in the car.

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Abstract: In this paper, we develop a vision-based system that employs a combined RGB and depth descriptor to classify hand gestures. The method is studied for a human-machine interface application in the car. Two interconnected modules are employed: one that detects a hand in the region of interaction and performs user classification, and another that performs gesture recognition. The feasibility of the system is demonstrated using a challenging RGBD hand gesture data set collected under settings of common illumination variation and occlusion.

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386 citations

Cites methods from "LIBSVM: A library for support vecto..."

...Because HIK SVM with the HOG + HOG2 descriptor showed good results, it is used in the remaining experiments....
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...ent modalities (RGB and depth) with different classification schemes (kernel choices for a support vector machine (SVM) classifier [18]) for finding the optimal combination and gain-...
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...For classification, an SVM classifier is employed [18]....
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...Each of the descriptors is compared over the different modalities (RGB and depth) with different classification schemes (kernel choices for a support vector machine (SVM) classifier [18]) for finding the optimal combination and gaining insights into the strengths and limitations of the different approaches....
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...SVM [18] is used in the experiments due to its popularity in...
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Journal Article•DOI•

Characterization of four-class motor imagery EEG data for the BCI-competition 2005.

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Alois Schlögl, Felix Yuan-Tseng Lee, Horst Bischof, Gert Pfurtscheller

16 Dec 2005-Journal of Neural Engineering

TL;DR: The results of the multi-channel analysis indicate SVM as the most successful classifier, whereas kNN performed worst, while the single-channel results gave rise to topographic maps that revealed the channels with the highest level of separability between classes for each subject.

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Abstract: To determine and compare the performance of different classifiers applied to four-class EEG data is the goal of this communication. The EEG data were recorded with 60 electrodes from five subjects performing four different motor-imagery tasks. The EEG signal was modeled by an adaptive autoregressive (AAR) process whose parameters were extracted by Kalman filtering. By these AAR parameters four classifiers were obtained, namely minimum distance analysis (MDA)--for single-channel analysis, and linear discriminant analysis (LDA), k-nearest-neighbor (kNN) classifiers as well as support vector machine (SVM) classifiers for multi-channel analysis. The performance of all four classifiers was quantified and evaluated by Cohen's kappa coefficient, an advantageous measure we introduced here to BCI research for the first time. The single-channel results gave rise to topographic maps that revealed the channels with the highest level of separability between classes for each subject. Our results of the multi-channel analysis indicate SVM as the most successful classifier, whereas kNN performed worst.

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386 citations

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References

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Journal Article•DOI•

Support-Vector Networks

[...]

Corinna Cortes¹, Vladimir Vapnik¹•Institutions (1)

Bell Labs¹

15 Sep 1995-Machine Learning

TL;DR: High generalization ability of support-vector networks utilizing polynomial input transformations is demonstrated and the performance of the support- vector network is compared to various classical learning algorithms that all took part in a benchmark study of Optical Character Recognition.

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Abstract: The support-vector network is a new learning machine for two-group classification problems. The machine conceptually implements the following idea: input vectors are non-linearly mapped to a very high-dimension feature space. In this feature space a linear decision surface is constructed. Special properties of the decision surface ensures high generalization ability of the learning machine. The idea behind the support-vector network was previously implemented for the restricted case where the training data can be separated without errors. We here extend this result to non-separable training data. High generalization ability of support-vector networks utilizing polynomial input transformations is demonstrated. We also compare the performance of the support-vector network to various classical learning algorithms that all took part in a benchmark study of Optical Character Recognition.

...read moreread less

37,861 citations

"LIBSVM: A library for support vecto..." refers background in this paper

...{1,-1}, C-SVC [Boser et al. 1992; Cortes and Vapnik 1995] solves 4LIBSVM Tools: http://www.csie.ntu.edu.tw/~cjlin/libsvmtools. the following primal optimization problem: l t min 1 w T w +C .i (1) w,b,. 2 i=1 subject to yi(w T f(xi) +b) =1 -.i, .i =0,i =1,...,l, where f(xi)maps xi into a…...
[...]

Statistical learning theory

[...]

Vladimir Vapnik

01 Jan 1998

TL;DR: Presenting a method for determining the necessary and sufficient conditions for consistency of learning process, the author covers function estimates from small data pools, applying these estimations to real-life problems, and much more.

...read moreread less

Abstract: A comprehensive look at learning and generalization theory. The statistical theory of learning and generalization concerns the problem of choosing desired functions on the basis of empirical data. Highly applicable to a variety of computer science and robotics fields, this book offers lucid coverage of the theory as a whole. Presenting a method for determining the necessary and sufficient conditions for consistency of learning process, the author covers function estimates from small data pools, applying these estimations to real-life problems, and much more.

...read moreread less

26,531 citations

"LIBSVM: A library for support vecto..." refers background in this paper

...Under given parameters C > 0and E> 0, the standard form of support vector regression [Vapnik 1998] is ll tt 1 T min w w + C .i + C .i * w,b,.,. * 2 i=1 i=1 subject to w T f(xi) + b- zi = E + .i, zi - w T f(xi) - b = E + .i * , * .i,.i = 0,i = 1,...,l....
[...]
...It can be clearly seen that C-SVC and one-class SVM are already in the form of problem (11)....
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..., l, in two classes, and a vector y ∈ Rl such that yi ∈ {1,−1}, C-SVC (Cortes and Vapnik, 1995; Vapnik, 1998) solves the following primal problem:...
[...]
...Then, according to the SVM formulation, svm train one calls a corresponding subroutine such as solve c svc for C-SVC and solve nu svc for ....
[...]
...Note that b of C-SVC and E-SVR plays the same role as -. in one-class SVM, so we de.ne ....
[...]

Proceedings Article•DOI•

A training algorithm for optimal margin classifiers

[...]

Bernhard E. Boser¹, Isabelle Guyon², Vladimir Vapnik²•Institutions (2)

University of California, Berkeley¹, Bell Labs²

01 Jul 1992

TL;DR: A training algorithm that maximizes the margin between the training patterns and the decision boundary is presented, applicable to a wide variety of the classification functions, including Perceptrons, polynomials, and Radial Basis Functions.

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Abstract: A training algorithm that maximizes the margin between the training patterns and the decision boundary is presented. The technique is applicable to a wide variety of the classification functions, including Perceptrons, polynomials, and Radial Basis Functions. The effective number of parameters is adjusted automatically to match the complexity of the problem. The solution is expressed as a linear combination of supporting patterns. These are the subset of training patterns that are closest to the decision boundary. Bounds on the generalization performance based on the leave-one-out method and the VC-dimension are given. Experimental results on optical character recognition problems demonstrate the good generalization obtained when compared with other learning algorithms.

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11,211 citations

"LIBSVM: A library for support vecto..." refers background in this paper

...It can be clearly seen that C-SVC and one-class SVM are already in the form of problem (11)....
[...]
...Then, according to the SVM formulation, svm train one calls a corresponding subroutine such as solve c svc for C-SVC and solve nu svc for ....
[...]
...Note that b of C-SVC and E-SVR plays the same role as -. in one-class SVM, so we de.ne ....
[...]
...In Section 2, we describe SVM formulations supported in LIBSVM: C-Support Vector Classi.cation (C-SVC), ....
[...]
...{1,-1}, C-SVC [Boser et al. 1992; Cortes and Vapnik 1995] solves 4LIBSVM Tools: http://www.csie.ntu.edu.tw/~cjlin/libsvmtools. the following primal optimization problem: l t min 1 w T w +C .i (1) w,b,. 2 i=1 subject to yi(w T f(xi) +b) =1 -.i, .i =0,i =1,...,l, where f(xi)maps xi into a higher-dimensional space and C > 0 is the regularization parameter....
[...]

A Practical Guide to Support Vector Classication

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Hsu Chih-Wei, Chih-Chung Chang¹, Chih-Jen Lin•Institutions (1)

National Taiwan University¹

01 Jan 2008

TL;DR: A simple procedure is proposed, which usually gives reasonable results and is suitable for beginners who are not familiar with SVM.

...read moreread less

Abstract: Support vector machine (SVM) is a popular technique for classication. However, beginners who are not familiar with SVM often get unsatisfactory results since they miss some easy but signicant steps. In this guide, we propose a simple procedure, which usually gives reasonable results.

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7,069 citations

"LIBSVM: A library for support vecto..." refers methods in this paper

...A Simple Example of Running LIBSVM While detailed instructions of using LIBSVM are available in the README file of the package and the practical guide by Hsu et al. [2003], here we give a simple example....
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...For instructions of using LIBSVM, see the README file included in the package, the LIBSVM FAQ,3 and the practical guide by Hsu et al. [2003]. LIBSVM supports the following learning tasks....
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Journal Article•DOI•

A comparison of methods for multiclass support vector machines

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Hsu Chih-Wei¹, Chih-Jen Lin¹•Institutions (1)

National Taiwan University¹

01 Mar 2002-IEEE Transactions on Neural Networks

TL;DR: Decomposition implementations for two "all-together" multiclass SVM methods are given and it is shown that for large problems methods by considering all data at once in general need fewer support vectors.

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Abstract: Support vector machines (SVMs) were originally designed for binary classification. How to effectively extend it for multiclass classification is still an ongoing research issue. Several methods have been proposed where typically we construct a multiclass classifier by combining several binary classifiers. Some authors also proposed methods that consider all classes at once. As it is computationally more expensive to solve multiclass problems, comparisons of these methods using large-scale problems have not been seriously conducted. Especially for methods solving multiclass SVM in one step, a much larger optimization problem is required so up to now experiments are limited to small data sets. In this paper we give decomposition implementations for two such "all-together" methods. We then compare their performance with three methods based on binary classifications: "one-against-all," "one-against-one," and directed acyclic graph SVM (DAGSVM). Our experiments indicate that the "one-against-one" and DAG methods are more suitable for practical use than the other methods. Results also show that for large problems methods by considering all data at once in general need fewer support vectors.

...read moreread less

6,562 citations