Latent Class Model with Application to Speaker Diarization

In this paper, we apply a latent class model (LCM) to the task of speaker diarization. LCM is similar to Patrick Kenny's variational Bayes (VB) method in that it uses soft information and avoids premature hard decisions in its iterations. In contrast to the VB method, which is based on a generative model, LCM provides a framework allowing both generative and discriminative models. The discriminative property is realized through the use of i-vector (Ivec), probabilistic linear discriminative analysis (PLDA), and a support vector machine (SVM) in this work. Systems denoted as LCM-Ivec-PLDA, LCM-Ivec-SVM, and LCM-Ivec-Hybrid are introduced. In addition, three further improvements are applied to enhance its performance. 1) Adding neighbor windows to extract more speaker information for each short segment. 2) Using a hidden Markov model to avoid frequent speaker change points. 3) Using an agglomerative hierarchical cluster to do initialization and present hard and soft priors, in order to overcome the problem of initial sensitivity. Experiments on the National Institute of Standards and Technology Rich Transcription 2009 speaker diarization database, under the condition of a single distant microphone, show that the diarization error rate (DER) of the proposed methods has substantial relative improvements compared with mainstream systems. Compared to the VB method, the relative improvements of LCM-Ivec-PLDA, LCM-Ivec-SVM, and LCM-Ivec-Hybrid systems are 23.5%, 27.1%, and 43.0%, respectively. Experiments on our collected database, CALLHOME97, CALLHOME00 and SRE08 short2-summed trial conditions also show that the proposed LCM-Ivec-Hybrid system has the best overall performance

First in Class? The Performance of Latent Class Model

Replaced with revised version of poster 07/22/11.Monte Carlo Simulations, Latent Class Model, Environmental Economics and Policy,

Identification of Segments of Thermo Energy Plants with a Latent Class Model

This paper identifies different groups in a cost function framework of thermo energy plants belonging to EDP-Electricity of Portugal. In particular, we have clustered the sample - comprising data for years 1987 to 2006 - into two groups. To do so, we have implemented a stochastic frontier latent class model, a procedure that also permits us to analyze also the efficiency of the thermo energy plants with respect to their own frontiers. The results reveal that some of the plants could improve their efficiency levels substantially.cost efficiency; latent class model; thermo energy plants; stochastic frontier.

Bayesian inference for Latent Class model via MCMC with application to capture-recapture data

In this paper we propose a Bayesian Latent Class model for capture-recapture data. Through two appliations, the first concerning a sample of snowshoe hares and the second concerning a sample of diabetics in a small Italian town, we show how the proposed approach may be effectively used to obtain point estimates and credibility intervals for the size of a closed-population. To estimate the model we use the Reversible Jump algorithm and the Delayed Rejection strategy to improve its efficiency.Bayesian Inference; Capture-recapture; Delayed Rejection; Latent Class model; Reversible Jump.

Solving the 100 Swiss Francs Problem

Sturmfels offered 100 Swiss Francs in 2005 to a conjecture, which deals with a special case of the maximum likelihood estimation for a latent class model. This paper confirms the conjecture positively

Identification of Segments of Thermo Energy Plants with a Latent Class Model

This paper identifies different groups in a cost function framework of thermo energy plants belonging to EDP-Electricity of Portugal. In particular, we have clustered the sample - comprising data for years 1987 to 2006 - into two groups. To do so, we have implemented a stochastic frontier latent class model, a procedure that also permits us to analyze also the efficiency of the thermo energy plants with respect to their own frontiers. The results reveal that some of the plants could improve their efficiency levels substantially.cost efficiency; latent class model; thermo energy plants; stochastic frontier.

A latent class model for obesity

We extend the discrete data latent class literature by explicitly defining a latent variable for class membership as a function of both observables and unobservables, thereby allowing the equations defining the class membership and observed outcomes to be correlated. The procedure is then applied to modelling observed obesity outcomes, based upon an underlying ordered probit equation

A latent class approach to investigating consumer demand for genetically modified staple food in a developing country: The case of GM bananas in Uganda

genetically modified bananas, Consumers, Choice experiment, latent class model, preference heterogeneity, Science and technology, Genetic resources, Genetically engineered crops, Genetically modified crops,

Do opening hours and unobserved heterogeneity affect economies of scale and scope in postal outlets?

The purpose of this study is to analyze the cost structure of Swiss Post’s postal outlets. In particular, the idea is to assess economies of scale and scope in post offices and franchised postal agencies. Information on their optimal size and production structure is of importance from the policy-makers’point of view because this hypothetical situation may be a basis for calculation of reimbursements when providing the universal service. Two important novelties are introduced in this study. First, the latent class model accounts for postal outlets with different underlying production technologies, caused by unobserved factors. Second, the cost model includes standby time as an indicator of public service because regulated accessibility and negotiated opening hours that enhance public service frequently lead to opening hours that exceed the time necessary to operate the demand. Overall, this analysis confirms the existence of increasing unexploited economies of scale and scope with falling outputs in the Swiss Post office network. Furthermore, the results for the latent class model point to the existence of unobserved heterogeneity in the industry.economies of scale, economies of scope, postal outlet network, unobserved heterogeneity, latent class model, opening hours, standby time

Detecting Technological Heterogeneity in New York Dairy Farms

Agricultural studies have often differentiated and estimated different technologies within a sample of farms. The common approach is to use observable farm characteristics to split the sample into several groups and subsequently estimate different functions for each group. Alternatively, unique technologies can be determined by econometric procedures such as latent class models. This paper compares the results of a latent class model with the use of a priori information to split the sample using dairy farm data in the application. Latent class separation appears to be a superior method of separating heterogeneous technologies.parlor milking system, stanchion milking system, latent class model, stochastic frontier, Production Economics,