Factorial Fractional Hidden Markov Models

Conventional hidden Markov models generally consist of a Markov chain observed through a linear map corrupted by additive Gaussian noise. A lesser known extension of this class of models, is the so called Factorial Hidden Model (FHMM). FHMM’s also have numerous applications, notably in machine learning and speech recognition. In this article we consider FHMM’s with additive fractional Gaussian noise in the observed process.Общепринятые марковские модели скрытия информации представляют собой марковскую цепь, полученную с помощью линейного преобразования, искаженного аддитивным гауссовым шумом. Менее известным расширением этого класса моделей является так называемая факториальная модель скрытия информации (FHMM), которая также имеет множество приложений, в частности при обучении машин и распознaвании речи. Рассмотрены FHMM с аддитивным дробным гауссовым шумом в наблюдаемом процессе.Загальновідомі марковські моделі приховування інформації являють собою ланцюг Маркова, отриманий за допомогою лінійного перетворення, викривленого адитивним гауссовим шумом. Меньше відомим розширенням цього класу моделей є так звана факторіальна модель приховування інформації (FHMM), яка також широко застосовується, наприклад, при навчанні машин и розпізнаванні мови. Розглянуто FHMM з адитивним дробовим гауссовим шумом у процесі, що спостерігається

Partially Observed Discrete-Valued Time Series in Fractional Gaussian Noise

Stochastic processes of counts have very broad applications in view of the host of integer-valued time series which cannot be satisfactorily handled within the classical framework of Gaussian-like series. In this paper we discuss recursive filters for partially observed discrete-valued time series where the noise in the observations is a fractional Gaussian noise.Стохастическая обработка отсчетов широко применяется в множестве задач, содержащих целочисленно-оцениваемые временные ряды, которыми нельзя удовлетворительно оперировать в рамках классических Гауссово-подобных рядов. Рассмотрены рекурсивные фильтры для частично наблюдаемых дискретно-оцениваемых рядов, в которых шумы наблюдений являются дробными Гауссовыми шумами.Стохастична обробка відліків широко застосовується у багатьох задачах з цілочислооцінюваними часовими рядами, котрими не можна задовільно оперувати в рамках класичних Гаусово-подібних рядів. Розглянуто рекурсивні фільтри для частково спостережуваних дискретно-оцінюваних рядів, в котрих шуми спостережень є дробовими Гаусовими шумами

Inter-areal coordination of columnar architectures during visual cortical development

The occurrence of a critical period of plasticity in the visual cortex has long been established, yet its function in normal development is not fully understood. Here we show that as the late phase of the critical period unfolds, different areas of cat visual cortex develop in a coordinated manner. Orientation columns in areas V1 and V2 become matched in size in regions that are mutually connected. The same age trend is found for such regions in the left and right brain hemisphere. Our results indicate that a function of critical period plasticity is to progressively coordinate the functional architectures of different cortical areas - even across hemispheres.Comment: 30 pages, 1 table, 6 figure

Using global analysis, partial specifications, and an extensible assertion language for program validation and debugging

We discuss a framework for the application of abstract interpretation as an aid during program development, rather than in the more traditional application of program optimization. Program validation and detection of errors is first performed statically by comparing (partial) specifications written in terms of assertions against information obtained from (global) static analysis of the program. The results of this process are expressed in the user assertion language. Assertions (or parts of assertions) which cannot be checked statically are translated into run-time tests. The framework allows the use of assertions to be optional. It also allows using very general properties in assertions, beyond the predefined set understandable by the static analyzer and including properties defined by user programs. We also report briefly on an implementation of the framework. The resulting tool generates and checks assertions for Prolog, CLP(R), and CHIP/CLP(fd) programs, and integrates compile-time and run-time checking in a uniform way. The tool allows using properties such as types, modes, non-failure, determinacy, and computational cost, and can treat modules separately, performing incremental analysis

Endothelial dysfunction in obese non-hypertensive children without evidence of sleep disordered breathing

<p>Abstract</p> <p>Background</p> <p>Endothelial dysfunction is a complication of both obesity and obstructive sleep apnea syndrome (OSAS), the latter being highly prevalent among obese children. It is unknown whether obesity causes endothelial dysfunction in children in the absence of OSAS. This study examines endothelial function in obese and non-obese children without OSAS.</p> <p>Methods</p> <p>Pre-pubertal non-hypertensive children were recruited. Endothelial function was assessed in a morning fasted state, using a modified hyperemic test involving cuff-induced occlusion of the radial and ulnar arteries. The absence of OSAS was confirmed by overnight polysomnography. Anthropometry was also performed.</p> <p>Results</p> <p>55 obese children (mean age 8.6 ± 1.4 years, mean BMI z-score: 2.3 ± 0.3) were compared to 50 non-obese children (mean age 8.0 ± 1.6 years, mean BMI z-score 0.3 ± 0.9). Significant delays to peak capillary reperfusion after occlusion release occurred in obese compared to non-obese children (45.3 ± 21.9 sec <it>vs</it>. 31.5 ± 14.1 sec, p < 0.01), but no differences in the magnitude of hyperemia emerged. Time to peak reperfusion and percentage of body fat were positively correlated (r = 0.365, p < 0.01).</p> <p>Conclusions</p> <p>Our findings confirm that endothelial dysfunction occurs early in life in obese children, even in the absence of OSAS. Thus, mechanisms underlying endothelial dysfunction in pediatric obesity are operational in the absence of sleep-disordered breathing.</p

End-of-life care and rituals in contexts of post-migration diversity in Europe:An introduction

No abstract available

Measure theory and filtering: Introduction and applications

This 2004 book is a resource for non-statisticians implementing filtering methods, which covers applications in finance, genetics and population