Dario García-García, Raúl Santos-Rodríguez, E. Parrado-Hernández
{"title":"Classifier-based affinities for clustering sets of vectors","authors":"Dario García-García, Raúl Santos-Rodríguez, E. Parrado-Hernández","doi":"10.1109/MLSP.2012.6349760","DOIUrl":"https://doi.org/10.1109/MLSP.2012.6349760","url":null,"abstract":"We focus on the task of clustering sets of vectors. This can be seen as a special case of sequence clustering when the dynamics are not taken into account. We propose to use the error probability of binary classifiers to obtain a measure of the affinity between two sets so that a standard similarity-based clustering algorithm can be applied.","PeriodicalId":262601,"journal":{"name":"2012 IEEE International Workshop on Machine Learning for Signal Processing","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121191185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jesus Fernandez-Bes, L. A. Azpicueta-Ruiz, Magno T. M. Silva, J. Arenas-García
{"title":"A novel scheme for diffusion networks with least-squares adaptive combiners","authors":"Jesus Fernandez-Bes, L. A. Azpicueta-Ruiz, Magno T. M. Silva, J. Arenas-García","doi":"10.1109/MLSP.2012.6349767","DOIUrl":"https://doi.org/10.1109/MLSP.2012.6349767","url":null,"abstract":"In this paper, we propose a novel diffusion scheme for adaptive networks, where each node preserves a pure local estimate of the unknown parameter vector and combines this estimate with other estimates received from neighboring nodes. The combination weights are adapted to minimize a local least-squares cost function. Simulations carried out in stationary and nonstationary scenarios show that the proposed scheme can outperform other existing schemes for diffusion networks with adaptive combiners in terms of tracking capability and convergence rate when the network nodes use different step sizes.","PeriodicalId":262601,"journal":{"name":"2012 IEEE International Workshop on Machine Learning for Signal Processing","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121469417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Perturbation regulated kernel regressors for supervised machine learning","authors":"S. Kung, Pei-Yuan Wu","doi":"10.1109/MLSP.2012.6349743","DOIUrl":"https://doi.org/10.1109/MLSP.2012.6349743","url":null,"abstract":"This paper develops a kernel perturbation-regulated (KPR) regressor based on the errors-in-variables models. KPR offers a strong smoothing capability critical to the robustness of regression or classification results. For Gaussian cases, the notion of orthogonal polynomials is instrumental to optimal estimation and its error analysis. More exactly, the regressor may be expressed as a linear combination of many simple Hermite Regressors, each focusing on one (and only one) orthogonal polynomial. For Gaussian or non-Gaussian cases, this paper formally establishes a “Two-Projection Theorem” allowing the estimation task to be divided into two projection stages: the first projection reveals the effect of model-induced error (caused by under-represented regressor models) while the second projection reveals the extra estimation error due to the (inevitable) input measuring error. The two-projection analysis leads to a closed-form error formula critical for order/error tradeoff. The simulation results not only confirm the theoretical prediction but also demonstrate superiority of KPR over the conventional ridge regression method in MSE reduction.","PeriodicalId":262601,"journal":{"name":"2012 IEEE International Workshop on Machine Learning for Signal Processing","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126399668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The discounted cumulative margin penalty: Rank-learning with a list-wise loss and pair-wise margins","authors":"C. Renjifo, C. Carmen","doi":"10.1109/MLSP.2012.6349807","DOIUrl":"https://doi.org/10.1109/MLSP.2012.6349807","url":null,"abstract":"In recent years, the fields of rank-learning and information retrieval have received substantial attention. Algorithms developed within these domains have shown promising results in a variety of problem spaces, especially in document retrieval and web search. In this paper, a new rank-learning algorithm is proposed that combines list-wise loss measurements with pair-wise margins. The list-wise loss term is inspired by the Normalized Discounted Cumulative Gain (NDCG) metric, and the resulting objective function is solvable with gradient-free optimization techniques. Experiments using the LETOR 3.0 and 4.0 collections demonstrate that the ranking performance achieved by an algorithm using this loss measure is competitive with reported baselines.","PeriodicalId":262601,"journal":{"name":"2012 IEEE International Workshop on Machine Learning for Signal Processing","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125649230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Pseudo inputs for pairwise learning with Gaussian processes","authors":"J. Nielsen, B. S. Jensen, Jan Larsen","doi":"10.1109/MLSP.2012.6349812","DOIUrl":"https://doi.org/10.1109/MLSP.2012.6349812","url":null,"abstract":"We consider learning and prediction of pairwise comparisons between instances. The problem is motivated from a perceptual view point, where pairwise comparisons serve as an effective and extensively used paradigm. A state-of-the-art method for modeling pairwise data in high dimensional domains is based on a classical pairwise probit likelihood imposed with a Gaussian process prior. While extremely flexible, this non-parametric method struggles with an inconvenient O(n3) scaling in terms of the n input instances which limits the method only to smaller problems. To overcome this, we derive a specific sparse extension of the classical pairwise likelihood using the pseudo-input formulation. The behavior of the proposed extension is demonstrated on a toy example and on two real-world data sets which outlines the potential gain and pitfalls of the approach. Finally, we discuss the relation to other similar approximations that have been applied in standard Gaussian process regression and classification problems such as FI(T)C and PI(T)C.","PeriodicalId":262601,"journal":{"name":"2012 IEEE International Workshop on Machine Learning for Signal Processing","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114080736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Souden, K. Kinoshita, Marc Delcroix, T. Nakatani
{"title":"Distributed microphone array processing for speech source separation with classifier fusion","authors":"M. Souden, K. Kinoshita, Marc Delcroix, T. Nakatani","doi":"10.1109/MLSP.2012.6349782","DOIUrl":"https://doi.org/10.1109/MLSP.2012.6349782","url":null,"abstract":"We propose a new approach for clustering and separating competing speech signals using a distributed microphone array (DMA). This approach can be viewed as an extension of expectation-maximization (EM)-based source separation to DMAs. To achieve distributed processing, we assume the conditional independence (with respect to sources' activities) of the normalized recordings of different nodes. By doing so, only the posterior probabilities of sources' activities need to be shared between nodes. Consequently, the EM algorithm is formulated such that at the expectation step, local posterior probabilities are estimated locally and shared between nodes. In the maximization step, every node fuses the received probabilities via either product or sum rules and estimates its local parameters. We show that, even if we make binary decisions (presence/ absence of speech) during EM iterations instead of transmitting continuous posterior probability values, we can achieve separation without causing significant speech distortion. Our preliminary investigations demonstrate that the proposed processing technique approaches the centralized solution and can outperform Oracle best node-wise clustering in terms of objective source separation metrics.","PeriodicalId":262601,"journal":{"name":"2012 IEEE International Workshop on Machine Learning for Signal Processing","volume":"138 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124329581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Kernel-based parametric validity index for assessing clusters from microarray gene expression data","authors":"Rui Fa, A. Nandi","doi":"10.1109/MLSP.2012.6349780","DOIUrl":"https://doi.org/10.1109/MLSP.2012.6349780","url":null,"abstract":"In this paper, we develop a kernel-based parametric validity index (KPVI), which not only inherits robust feature from the newly proposed PVI, but possesses extra superiority inherited from the kernel method. The KPVI employs the kernel method to calculate both the inter-cluster and the intra cluster dissimilarities. Furthermore, we develop several rules to guide the selection of parameter values by examining the dissimilarity densities of different datasets such that the maximal appropriate values of the parameters for individual dataset can be obtained. We evaluate the new KPVI for assessing five clustering algorithms in both synthetic and real gene expression datasets. The experimental results support that the KPVI has the most superior performance among the existing validation algorithms, even better than the PVI.","PeriodicalId":262601,"journal":{"name":"2012 IEEE International Workshop on Machine Learning for Signal Processing","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124727702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. V. Vaerenbergh, I. Santamaría, M. Lázaro-Gredilla
{"title":"Estimation of the forgetting factor in kernel recursive least squares","authors":"S. V. Vaerenbergh, I. Santamaría, M. Lázaro-Gredilla","doi":"10.1109/MLSP.2012.6349749","DOIUrl":"https://doi.org/10.1109/MLSP.2012.6349749","url":null,"abstract":"In a recent work we proposed a kernel recursive least-squares tracker (KRLS-T) algorithm that is capable of tracking in non-stationary environments, thanks to a forgetting mechanism built on a Bayesian framework. In order to guarantee optimal performance its parameters need to be determined, specifically its kernel parameters, regularization and, most importantly in non-stationary environments, its forgetting factor. This is a common difficulty in adaptive filtering techniques and in signal processing algorithms in general. In this paper we demonstrate the equivalence between KRLS-T's recursive tracking solution and Gaussian process (GP) regression with a specific class of spatio-temporal covariance. This result allows to use standard hyperparameter estimation techniques from the Gaussian process framework to determine the parameters of the KRLS-T algorithm. Most notably, it allows to estimate the optimal forgetting factor in a principled manner. We include results on different benchmark data sets that offer interesting new insights.","PeriodicalId":262601,"journal":{"name":"2012 IEEE International Workshop on Machine Learning for Signal Processing","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116756774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tue Herlau, Morten Mørup, Mikkel N. Schmidt, L. K. Hansen
{"title":"Modelling dense relational data","authors":"Tue Herlau, Morten Mørup, Mikkel N. Schmidt, L. K. Hansen","doi":"10.1109/MLSP.2012.6349747","DOIUrl":"https://doi.org/10.1109/MLSP.2012.6349747","url":null,"abstract":"Relational modelling classically consider sparse and discrete data. Measures of influence computed pairwise between temporal sources naturally give rise to dense continuous-valued matrices, for instance p-values from Granger causality. Due to asymmetry or lack of positive definiteness they are not naturally suited for kernel K-means. We propose a generative Bayesian model for dense matrices which generalize kernel K-means to consider off-diagonal interactions in matrices of interactions, and demonstrate its ability to detect structure on both artificial data and two real data sets.","PeriodicalId":262601,"journal":{"name":"2012 IEEE International Workshop on Machine Learning for Signal Processing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129321902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"ECG-based biometrics: A real time classification approach","authors":"A. Lourenço, H. Silva, A. Fred","doi":"10.1109/MLSP.2012.6349735","DOIUrl":"https://doi.org/10.1109/MLSP.2012.6349735","url":null,"abstract":"Behavioral biometrics is one of the areas with growing interest within the biosignal research community. A recent trend in the field is ECG-based biometrics, where electrocardiographic (ECG) signals are used as input to the biometric system. Previous work has shown this to be a promising trait, with the potential to serve as a good complement to other existing, and already more established modalities, due to its intrinsic characteristics. In this paper, we propose a system for ECG biometrics centered on signals acquired at the subject's hand. Our work is based on a previously developed custom, non-intrusive sensing apparatus for data acquisition at the hands, and involved the pre-processing of the ECG signals, and evaluation of two classification approaches targeted at real-time or near real-time applications. Preliminary results show that this system leads to competitive results both for authentication and identification, and further validate the potential of ECG signals as a complementary modality in the toolbox of the biometric system designer.","PeriodicalId":262601,"journal":{"name":"2012 IEEE International Workshop on Machine Learning for Signal Processing","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133217650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}