Jose Niño - Academia.edu (original) (raw)

Papers by Jose Niño

IEEE Computer Applications in Power, 2001

This paper addresses the problem of dynamic bandwidth allocation in a channel to multiclass packe... more This paper addresses the problem of dynamic bandwidth allocation in a channel to multiclass packet traffic, where each traffic class has a finite dedicated buffer. Class-dependent linear holding and rejection cost rates are used to model differing levels of tolerance to delay and loss. Time is slotted, and the controller's backlog information is delayed by one slot. The goal is to design well-grounded and tractable scheduling policies that nearly minimize expected total discounted or long-run average cost. New dynamic index policies are introduced, awarding higher priority to classes with larger index values, where a class' index measures the marginal productivity of work at its current state. The results are obtained by deploying the work-cost analysis approach to marginal productivity indices (MPIs) for restless bandits developed by the author. The results of a computational study on two-class instances are reported, shedding light on how the MPI policy's relative performance varies with each parameter. Across the range of instances explored, the MPI policy is shown to be nearly optimal, and to substantially outperform conventional benchmark policies.

Page 1. Computing an Index Policy for Bandits with Switching Penalties (Invited Paper) José Niño-... more Page 1. Computing an Index Policy for Bandits with Switching Penalties (Invited Paper) José Niño-Mora Department of Statistics Universidad Carlos III de Madrid C/ Madrid 126 28903 Getafe (Madrid), Spain jnimora@alum.mit.edu ...

Top, 2007

This paper surveys recent work by the author on the theoretical and algorithmic aspects of restle... more This paper surveys recent work by the author on the theoretical and algorithmic aspects of restless bandit indexation as well as on its application to a variety of problems involving the dynamic allocation of priority to multiple stochastic projects. The main aim is to present ideas and methods in an accessible form that can be of use to researchers addressing problems of such a kind. Besides building on the rich literature on bandit problems, our approach draws on ideas from linear programming, economics, and multi-objective optimization. In particular, it was motivated to address issues raised in the seminal work of Whittle (Restless bandits: activity allocation in a changing world. In: Gani J. (ed.) A Celebration of Applied Probability, J. Appl. Probab., vol. 25A, Applied Probability Trust, Sheffield, pp. 287–298, 1988) where he introduced the index for restless bandits that is the starting point of this work. Such an index, along with previously proposed indices and more recent extensions, is shown to be unified through the intuitive concept of “marginal productivity index” (MPI), which measures the marginal productivity of work on a project at each of its states. In a multi-project setting, MPI policies are economically sound, as they dynamically allocate higher priority to those projects where work appears to be currently more productive. Besides being tractable and widely applicable, a growing body of computational evidence indicates that such index policies typically achieve a near-optimal performance and substantially outperform benchmark policies derived from conventional approaches.

Revista Brasileira De Psiquiatria, 2004

Baseando-se numa revisão, apresentada pela Organização Mundial da Saúde (OMS), de recentes estudo... more Baseando-se numa revisão, apresentada pela Organização Mundial da Saúde (OMS), de recentes estudos sobre avaliação do custo social e de saúde decorrentes do uso do álcool, este artigo tem o objetivo de expor as evidências que permitem avaliar o consumo do álcool para além da esfera médica assistencial, pessoal e familiar, como questão prioritária do ponto de vista sócio-político e de saúde pública. São discutidos os dados mundiais e enfatizados os dados específicos do cenário brasileiro. O custo social é dimensionado com metodologia aplicada a diversos fatores, sendo unificados dados sobre violência, problemas familiares, abuso de menores, desordem pública, problemas profissionais, entre outros. O custo dos problemas de saúde é evidenciado pelo método epidemiológico, por meio de uma categorização elementar de dados de morbi-mortalidade geral de cada região e sub-região continental e triangulando-se dados de volume médio de consumo e padrões de consumo. Os resultados finais são obtidos através de análise comparativa de risco, utilizando-se basicamente um indicador representativo do número de anos de vida útil perdidos por adoecimento ou mortalidade precoce atribuíveis ao consumo do álcool, na língua inglesa designado "DALYs" (Disability Adjusted Life Years). O valor global do "DALYs", no ano de 2000, para o álcool, foi de 4% da morbi-mortalidade mundial, revelando tendência de ascensão. Os gradientes encontrados entre as diversas regiões do planeta são analisados à luz de uma crítica de seus potenciais determinantes.

Experimental Cell Research, 1999

A continuous source of osteoblasts for normal bone maintenance, as well as remodeling and regener... more A continuous source of osteoblasts for normal bone maintenance, as well as remodeling and regeneration during fracture repair, is ensured by the mesenchymal osteoprogenitor stem cells of the bone marrow (BM). The differentiation and maturation of osteoprogenitor cells into osteoblasts are thought to be modulated by transforming growth factors-β (TGF-β1 and TGF-β2) and TGF-β-related bone morphogenetic proteins (BMPs). To define

Measurement Science & Technology, 2009

Power transformers' reliability can be seriously affected by partial discharges. For this reason,... more Power transformers' reliability can be seriously affected by partial discharges. For this reason, it is necessary to implement technical methods to identify endangered equipment before catastrophic failures occur. A well-known method that can be applied either in the laboratory or in the field is the detection and localization of partial discharges, by means of the analysis of the acoustic signals they produced. An innovative partial discharge detector was developed based on the analysis of an acoustic or electrical PD signal envelope. This paper describes the architecture of the developed acoustic detector, which is composed of a set of ultrasonic sensors, signal conditioning and control modules, a graphical interface and the required software for the location of the affected area within the transformer. The conditioning and control modules perform analog to digital conversion, arrival time measurement, communication and control operations. Finally, some power transformer diagnostic testing is presented and discussed.

We show that if performance measures in a stochastic scheduling problem satisfy a set of so-calle... more We show that if performance measures in a stochastic scheduling problem satisfy a set of so-called partial conservation laws (PCL), which extend previously studied generalized conservation laws (GCL), then the problem is solved optimally by a priority-index policy for an appropriate range of linear performance objectives, where the optimal indices are computed by a one-pass adaptive-greedy algorithm, based on Klimov's. We further apply this framework to investigate the indexability property of restless bandits introduced by Whittle, obtaining the following results: (1) we identify a class of restless bandits (PCL-indexable) which are indexable;

Mathematics of Operations Research, 2006

This paper presents a framework grounded on convex optimization and economics ideas to solve by i... more This paper presents a framework grounded on convex optimization and economics ideas to solve by index policies problems of optimal dynamic allocation of effort to a discrete-state (finite or countable) binary-action (work/rest) semi-Markov restless bandit project, elucidating issues raised by previous work. Its contributions include: (i) the concept of a restless bandit's marginal productivity index (MPI), characterizing optimal policies relative to general cost and work measures; (ii) the characterization of indexable restless bandits as those satisfying diminishing marginal returns to work, consistently with a nested family of threshold policies; (iii) sufficient indexability conditions via partial conservation laws (PCLs); (iv) the characterization of the MPI as an optimal marginal productivity rate relative to feasible active-state sets; (v) application to semi-Markov bandits under several criteria, including a new mixed average-bias criterion; and (vi) PCL-indexability analyses and MPIs for optimal service control of make-to-order/make-to-stock queues with convex holding costs, under discounted and average-bias criteria.

Se empieza por revisar el papel de la Atención Primaria en la Estrategia del Sistema Nacional de ... more Se empieza por revisar el papel de la Atención Primaria en la Estrategia del Sistema Nacional de Salud para la Salud Mental, señalando la inadecuación de las soluciones propuestas para abordar los trastornos comunes (ansiedad y depresión) con su naturaleza de problemas de tipo psicológico. Se propone la integración de la Psicología en Atención Primaria sobre la base de una filosofía contextual, distinta a la derivada del modelo biomédico y biopsicosocial al uso. Esta nueva filosofía incluye un replanteamiento de los problemas psicológicos en términos contextuales, ligados a la vida, y no en términos psicopatológicos, ligados a la biología. En esta línea, se introduce la figura del consultor psicológico de salud, definiendo el papel del psicólogo en Atención Primaria. Se termina por mostrar que el nuevo papel de la psicología en Atención Primaria está avalado por la eficacia, la rentabilidad y la preferencia de los usuarios. Palabras clave: Intevención psicológica. Atención primaria. Salud mental. Modelo bio-psico-social. Modelo contextual.

IEEE Computer Applications in Power, 2001

This paper addresses the problem of dynamic bandwidth allocation in a channel to multiclass packe... more This paper addresses the problem of dynamic bandwidth allocation in a channel to multiclass packet traffic, where each traffic class has a finite dedicated buffer. Class-dependent linear holding and rejection cost rates are used to model differing levels of tolerance to delay and loss. Time is slotted, and the controller's backlog information is delayed by one slot. The goal is to design well-grounded and tractable scheduling policies that nearly minimize expected total discounted or long-run average cost. New dynamic index policies are introduced, awarding higher priority to classes with larger index values, where a class' index measures the marginal productivity of work at its current state. The results are obtained by deploying the work-cost analysis approach to marginal productivity indices (MPIs) for restless bandits developed by the author. The results of a computational study on two-class instances are reported, shedding light on how the MPI policy's relative performance varies with each parameter. Across the range of instances explored, the MPI policy is shown to be nearly optimal, and to substantially outperform conventional benchmark policies.

Page 1. Computing an Index Policy for Bandits with Switching Penalties (Invited Paper) José Niño-... more Page 1. Computing an Index Policy for Bandits with Switching Penalties (Invited Paper) José Niño-Mora Department of Statistics Universidad Carlos III de Madrid C/ Madrid 126 28903 Getafe (Madrid), Spain jnimora@alum.mit.edu ...

Top, 2007

This paper surveys recent work by the author on the theoretical and algorithmic aspects of restle... more This paper surveys recent work by the author on the theoretical and algorithmic aspects of restless bandit indexation as well as on its application to a variety of problems involving the dynamic allocation of priority to multiple stochastic projects. The main aim is to present ideas and methods in an accessible form that can be of use to researchers addressing problems of such a kind. Besides building on the rich literature on bandit problems, our approach draws on ideas from linear programming, economics, and multi-objective optimization. In particular, it was motivated to address issues raised in the seminal work of Whittle (Restless bandits: activity allocation in a changing world. In: Gani J. (ed.) A Celebration of Applied Probability, J. Appl. Probab., vol. 25A, Applied Probability Trust, Sheffield, pp. 287–298, 1988) where he introduced the index for restless bandits that is the starting point of this work. Such an index, along with previously proposed indices and more recent extensions, is shown to be unified through the intuitive concept of “marginal productivity index” (MPI), which measures the marginal productivity of work on a project at each of its states. In a multi-project setting, MPI policies are economically sound, as they dynamically allocate higher priority to those projects where work appears to be currently more productive. Besides being tractable and widely applicable, a growing body of computational evidence indicates that such index policies typically achieve a near-optimal performance and substantially outperform benchmark policies derived from conventional approaches.

Revista Brasileira De Psiquiatria, 2004

Baseando-se numa revisão, apresentada pela Organização Mundial da Saúde (OMS), de recentes estudo... more Baseando-se numa revisão, apresentada pela Organização Mundial da Saúde (OMS), de recentes estudos sobre avaliação do custo social e de saúde decorrentes do uso do álcool, este artigo tem o objetivo de expor as evidências que permitem avaliar o consumo do álcool para além da esfera médica assistencial, pessoal e familiar, como questão prioritária do ponto de vista sócio-político e de saúde pública. São discutidos os dados mundiais e enfatizados os dados específicos do cenário brasileiro. O custo social é dimensionado com metodologia aplicada a diversos fatores, sendo unificados dados sobre violência, problemas familiares, abuso de menores, desordem pública, problemas profissionais, entre outros. O custo dos problemas de saúde é evidenciado pelo método epidemiológico, por meio de uma categorização elementar de dados de morbi-mortalidade geral de cada região e sub-região continental e triangulando-se dados de volume médio de consumo e padrões de consumo. Os resultados finais são obtidos através de análise comparativa de risco, utilizando-se basicamente um indicador representativo do número de anos de vida útil perdidos por adoecimento ou mortalidade precoce atribuíveis ao consumo do álcool, na língua inglesa designado "DALYs" (Disability Adjusted Life Years). O valor global do "DALYs", no ano de 2000, para o álcool, foi de 4% da morbi-mortalidade mundial, revelando tendência de ascensão. Os gradientes encontrados entre as diversas regiões do planeta são analisados à luz de uma crítica de seus potenciais determinantes.

Experimental Cell Research, 1999

A continuous source of osteoblasts for normal bone maintenance, as well as remodeling and regener... more A continuous source of osteoblasts for normal bone maintenance, as well as remodeling and regeneration during fracture repair, is ensured by the mesenchymal osteoprogenitor stem cells of the bone marrow (BM). The differentiation and maturation of osteoprogenitor cells into osteoblasts are thought to be modulated by transforming growth factors-β (TGF-β1 and TGF-β2) and TGF-β-related bone morphogenetic proteins (BMPs). To define

Measurement Science & Technology, 2009

Power transformers' reliability can be seriously affected by partial discharges. For this reason,... more Power transformers' reliability can be seriously affected by partial discharges. For this reason, it is necessary to implement technical methods to identify endangered equipment before catastrophic failures occur. A well-known method that can be applied either in the laboratory or in the field is the detection and localization of partial discharges, by means of the analysis of the acoustic signals they produced. An innovative partial discharge detector was developed based on the analysis of an acoustic or electrical PD signal envelope. This paper describes the architecture of the developed acoustic detector, which is composed of a set of ultrasonic sensors, signal conditioning and control modules, a graphical interface and the required software for the location of the affected area within the transformer. The conditioning and control modules perform analog to digital conversion, arrival time measurement, communication and control operations. Finally, some power transformer diagnostic testing is presented and discussed.

We show that if performance measures in a stochastic scheduling problem satisfy a set of so-calle... more We show that if performance measures in a stochastic scheduling problem satisfy a set of so-called partial conservation laws (PCL), which extend previously studied generalized conservation laws (GCL), then the problem is solved optimally by a priority-index policy for an appropriate range of linear performance objectives, where the optimal indices are computed by a one-pass adaptive-greedy algorithm, based on Klimov's. We further apply this framework to investigate the indexability property of restless bandits introduced by Whittle, obtaining the following results: (1) we identify a class of restless bandits (PCL-indexable) which are indexable;

Mathematics of Operations Research, 2006

This paper presents a framework grounded on convex optimization and economics ideas to solve by i... more This paper presents a framework grounded on convex optimization and economics ideas to solve by index policies problems of optimal dynamic allocation of effort to a discrete-state (finite or countable) binary-action (work/rest) semi-Markov restless bandit project, elucidating issues raised by previous work. Its contributions include: (i) the concept of a restless bandit's marginal productivity index (MPI), characterizing optimal policies relative to general cost and work measures; (ii) the characterization of indexable restless bandits as those satisfying diminishing marginal returns to work, consistently with a nested family of threshold policies; (iii) sufficient indexability conditions via partial conservation laws (PCLs); (iv) the characterization of the MPI as an optimal marginal productivity rate relative to feasible active-state sets; (v) application to semi-Markov bandits under several criteria, including a new mixed average-bias criterion; and (vi) PCL-indexability analyses and MPIs for optimal service control of make-to-order/make-to-stock queues with convex holding costs, under discounted and average-bias criteria.

Se empieza por revisar el papel de la Atención Primaria en la Estrategia del Sistema Nacional de ... more Se empieza por revisar el papel de la Atención Primaria en la Estrategia del Sistema Nacional de Salud para la Salud Mental, señalando la inadecuación de las soluciones propuestas para abordar los trastornos comunes (ansiedad y depresión) con su naturaleza de problemas de tipo psicológico. Se propone la integración de la Psicología en Atención Primaria sobre la base de una filosofía contextual, distinta a la derivada del modelo biomédico y biopsicosocial al uso. Esta nueva filosofía incluye un replanteamiento de los problemas psicológicos en términos contextuales, ligados a la vida, y no en términos psicopatológicos, ligados a la biología. En esta línea, se introduce la figura del consultor psicológico de salud, definiendo el papel del psicólogo en Atención Primaria. Se termina por mostrar que el nuevo papel de la psicología en Atención Primaria está avalado por la eficacia, la rentabilidad y la preferencia de los usuarios. Palabras clave: Intevención psicológica. Atención primaria. Salud mental. Modelo bio-psico-social. Modelo contextual.