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King, Brett. "Optimal mine scheduling policies." Thesis, Imperial College London, 2000. http://hdl.handle.net/10044/1/8458.
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Wan, Ziqi. "Scheduling Policies for Cloud Computing." Master's thesis, Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/328227.
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Computer and Information ScienceM.S.
Cloud computing focuses on maximizing the effectiveness of the shared resources. Cloud resources are usually not only shared by multiple users but are also dynamically reallocated per demand. This can work for allocating resources to users. This leads to task scheduling as a core and challenging issue in cloud computing. This thesis gives different scheduling strategies and algorithms in cloud computing. For a common cloud user, there is a great potential to boost the performance of mobile devices by offloading computation-intensive parts of mobile applications to the cloud. However, this potential is hindered by a gap between how individual mobile devices demand computational resources and how cloud providers offer them. In this thesis, we present the design of utility-based uploads sharing strategy in cloud scenarios, which bridges the above gap through providing computation offloading as a service to mobile devices. Our scheme efficiently manages cloud resources for offloading requests to improve offloading performances of mobile devices, as well as to reduce the monetary cost per request of the provider. However, from the viewpoint of data centers, resource limitations in both bandwidth and computing triggers a variety of resource management problems. In this thesis, we discuss the tradeoff between locality and load balancing, along with the multi-layer topology of data centers. After that, we investigate the interrelationship between the time cost and the virtual machine rent cost, and formalize it as the parallel speedup pattern. We then design several algorithms by adopting the idea of minimizing the utility cost. Furthermore, we focus on the detail of MapReduce framework in Cloud. For different MapReduce phases, there are different resource requirements. We propose a new scheduling algorithm based on the idea of combining map shuffle pairs, which has better performance than the popular min-max time first algorithm in minimizing the average makespan of tasks in the job matrix. Directions for future research mainly focus on the large scale implementation of our proposed solution. There are a wide variety of open questions remaining with respect to the design of algorithms to minimize response time. Further, it is interesting and important to understand how to schedule in order to minimize other performance metrics.
Temple University--Theses
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Núñez, del Toro Alma Cristina. "Scheduling policies for multi-period services." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/384932.
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In many situations, the resources in organizations are employed to satisfy some demand (or services) requirements, which are repeated with some periodicity. These recurrent services appear in a large variety of processes such as manufacturing, logistics and several other types of services. In this thesis, we focus on a particular family of problems involving the planning of recurrent services. In these problems resources are assigned to offer recurrent services over a planning horizon. Even if these problems can be classified as scheduling problems, this specific characteristic makes them differ from the typical scheduling problems studied in the literature. A very special characteristic of the problems that we study is that services are considered as single-period tasks. That is, the time needed to start and complete a service never exceeds one time period of the planning horizon. Furthermore, we focus on identifying the single periods when each service is repeated within the time horizon, instead of on the sequence according to which the different services are executed along the time horizon. We concentrate on modelling aspects for recurrent service problems with single-period duration,and on solution techniques for efficiently finding solutions. Particular emphasis is placed on the study of the strategy that is followed to offer the services over the planning horizon, that is, the policy for scheduling. Our aim is to analyze different options for such scheduling policies.The purpose is to provide enough support to decision makers to determine the convenience of using (or not) flexible policies as an alternative to regular strategies.For this, we study alternative models for two different scheduling policies. These models are addressed from a mathematical programming point of view and, therefore, we present several Mixed Integer Linear Programming (MILP) formulations. We develop two different types of formulations: the first type can be seen as a natural initial approach to the problem and produces sparse coefficients matrices whereas the second type is focused on determining the very first service period for each customer and gives dense matrices. For each type of formulation, we present two versions: an extensive and a compact one. In the first one decision variables are associated with individual demand customers whereas in the second one decision variables are associated with classes of customers with similar characteristics. For the regular policy we develop the both types of formulations whereas for the flexible policy we only study the extensive formulation. The formulations for each policy are compared trough extensive computational experience. Since the flexible policy results harder to solve than the regular one, we make use of combinatorial optimization techniques that permit alternative solution methods.In particular, we propose two different formulations suitable for column generation (CG).For each formulation we study the pricing subproblem that allows generating new columns, the initialization phase, as well as a procedure to tackle infeasibility issues. Additionally, we apply stabilization procedures in order to avoid the generation of an excessive of columns. Each CG algorithm is embedded within a branch-and-price (BP) framework, which combines different branching strategies. The BP was implemented for each CG formulation producing very interesting results that we present and analyze. Heuristics are alternative combinatorial optimization techniques that provide optimal and near optimal values within small computational times. In this thesis we also propose a heuristic algorithm suitable for both of scheduling policies.The heuristic produces good quality solutions for the studied problems, specially for the flexible policy. Finally, the structure of the solutions obtained with both scheduling policies are analyzed giving important insights on the trade-off between the regular and the flexible policies.En muchas situaciones los recursos en las organizaciones se usan para satisfacer requerimientos de demanda (o servicios) los cuales se repiten con cierta periodicidad. Estos servicios recurrentes aparecen en una gran variedad de procesos de manufactura, logística y varios otros tipos de servicios. Esta tesis aborda una familia de problemas en donde los recursos deben ser asignados para ofrecer servicios recurrentes sobre un horizonte de planeación. Estos problemas tienen ciertas características que los hacen distintos a los problemas típicos de calendarización encontrados en la literatura. Una de ellas es que los servicios son tareas de periodo unitario. Esto es, el tiempo necesario para comenzar y terminar un servicio nunca excede de un periodo de tiempo del horizonte de planeación. Además, en este tipo de problemas no enfocamos en determinar los periodos en los que cada servicio será repetido, en lugar de la secuenciación en que los diferentes servicios son ejecutados. En particular, nos concentramos en aspectos de modelización para los problemas de servicios recurrentes con duración de periodo simple así como en técnicas de resolución para encontrar soluciones eficientes. Hacemos particular énfasis en el estudio de la estrategia a seguir para ofrecer los servicios, esto es, la política de calendarización. Nuestro propósito es el análisis de distintas opciones para tales políticas. El objetivo es proveer soporte suficiente para los tomadores de decisiones en cuanto a la conveniencia de usar (o no) políticas flexibles como alternativa a estrategias regulares. Para ello estudiamos modelos alternativos para dos diferentes políticas de calendarización. Estos modelos se estudian desde una perspectiva de programación matemática y, por tanto, se presentan varias formulaciones de programación lineal mixta entera. En esta tesis desarrollamos dos tipos de formulaciones: el primer tipo puede verse como un acercamiento natural al problema y produce matrices con coeficientes dispersos mientras que el segundo tipo se enfoca en determinar el primer periodo de servicio para cada cliente y da como resultado matrices densas. Para cada tipo de formulación presentamos dos versiones: una extensa y una compacta. En la primera, las variables de decisión están asociadas a clientes individuales mientras que en la segunda, las variables de decisión se asocian con clases de clientes con características similares. Para la política regular desarrollamos formulaciones de las dos versiones mientras que para la política flexible únicamente estudiamos formulaciones extensas. Las formulaciones para cada política son comparadas por medio de una amplia experiencia computacional. Debido a que la política flexible resulta más difícil de resolver que la regular, usamos técnicas de optimización combinatoria que permiten métodos alternativos de solución. En particular, proponemos dos formulaciones distintas, ambas adecuadas para generación de columnas (GC). Para cada formulación estudiamos el subproblema de pricing para generar nuevas columnas, la fase de inicialización así como un procedimiento para atacar temas de infactibilidad. Además, aplicamos procedimientos de estabilización con el objetivo de evitar la generación de un número excesivo de columnas. Cada algoritmo de GC ha sido incrustado dentro de una estructura de branch-and-price (BP), el cual combina diferentes estrategias de ramificación. El BP ha sido implementado para cada formulación de GC produciendo resultados interesantes los cuales presentamos y analizamos. En este trabajo también proponemos un algoritmo heurístico adaptable para ambas políticas de calendarización. Las heurísticas producen soluciones de buena calidad para los problemas estudiados, especialmente para la política flexible. Finalmente, la estructura de las soluciones obtenidas con ambas políticas se analizan, obteniendo ideas importantes en cuanto a la compensación entre las políticas regulares y las flexibles.
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Mitchell, Helen Margaret. "Index policies for complex scheduling problems." Thesis, University of Newcastle Upon Tyne, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397534.
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Matondang, Abdul Rahim. "Evaluation of real time scheduling policies using simulation." Thesis, Cranfield University, 1988. http://hdl.handle.net/1826/3704.
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The purpose of this research is to investigate the effects
of different scheduling operating policies in real- time
scheduling. The scheduling policies include due date
assignment method, priority rules, process batch method and
operator reassignment policy. A specific case of
production scheduling-in a hypothetical assembled product
manufacturing system was investigated in this research.
The simulated production system encompasses fifteen work
centres, each containing one to three identical machines
and each machine requires one operator with all operations
being perfectly efficient on all machine types. The
production -system produces finished products as well as
components and sub-assemblies. Orders from outside the
system arrive for service generated according to the
exponential distribution. The orders coming to the system
were classified into "priority" and "standard" orders.
Processing times at each work centre are statistically
independent and uniformly distributed.
A computer simulation technique was chosen as the approach
method. A computer simulation written in DBASE III PLUS
was used to generate the data for analysis. In order to
analyse the behaviour of the simulated production system
with respect to the different performance criteria, a
number of performance measures were selected. These are,
mean tardiness, percent tardy, mean work in progress, mean
machine utilisation, and mean operator utilisation.
The 2x6x2x2 complete factorial is analysed by the
analysis of variance (ANOVA) procedure to statistically
determine whether due date assignment method, priority
rules, process batch method, and operator reassignment
policy or their interaction significantly affect the performance criteria considered. Further analysis to
identify where significant differences in performance occur
is conducted via Duncan multiple comparison test.
Based upon the statistical analysis it was found that the
relative impact of due date assignment method, priority
rule, process batch method, and operator reassignment
policy or their interaction for scheduling policies in real
time scheduling to be dependent upon the measure of
performance considered. In respect of root mean square of
tardiness, the scheduling policies involving the slack time
remaining (STR) priority rule are the most important of
scheduling policies in minimising the tardiness of customer
orders produced by the company. In respect to minimising
the work in progress, there is no dominant level of due
date assignment method, or priority rule or process batch
method or operator reassignment policy. However, the
scheduling policies involving the variable process batch
(VPB) method produce the best result.
The scheduling policies involving the variable process
batch (VPB) method are the best performers in maximising
the utilisation of machine and operator.
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PERES, IGOR TONA. "SIMULATION OF APPOINTMENT-SCHEDULING POLICIES IN OUTPATIENT SERVICES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=31401@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
FUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DO RIO DE JANEIRO
BOLSA NOTA 10
Os sistemas de agendamento de consultas tradicionalmente realizam as marcações dos pacientes em intervalos fixos de tempo, sem levar em consideração diversos fatores de complexidade do sistema de saúde. Isso pode causar mão de obra ociosa em alguns períodos do dia e longas filas de espera de pacientes em outros momentos. Nesse contexto, esta dissertação tem como intuito propor uma nova política de agendamento para uma clínica especializada em cirurgia bariátrica do Rio de Janeiro, considerando os fatores desse sistema: tempos de serviços estocásticos, impontualidade do paciente, atrasos e interrupções do serviço, e presenças de no-shows. Esta dissertação analisou diversos cenários com overbooking (marcação de pacientes adicionais), e testou as principais políticas por meio de simulação, propondo a mais adequada para a clínica. As 18 políticas de agendamento aplicadas foram encontradas através de uma extensa revisão sistemática da literatura. Com a utilização da política de agendamento OFFSET, foi possível aumentar o número de atendimentos em 30 por cento para o agendamento do principal provedor da clínica, mantendo o nível de serviço prestado. Além disto, foi proposta uma nova política de agendamento, denominada DOME CYCLE, que teve resultados superiores às demais políticas da literatura na média dos cenários realizados.
Appointment-scheduling systems traditionally schedule patient appointments at fixed intervals, without taking into account several complexity factors of health-care system. This schedule can make the server idle at certain times of the day and can produce long queues of patients at other times. In this context, the objective of this study is to propose a new scheduling policy for a clinic specialized in bariatric surgery in Rio de Janeiro, considering the following factors of this system: stochastic service times, patient unpunctuality, delays and interruptions of the provider and presences of no-shows. This study analyzed several scenarios with overbooking, and tested the main policies with a simulation model, proposing the most appropriate for the clinic. The 18 scheduling policies applied were found through an extensive systematic review of the literature. With the use of the OFFSET scheduling policy, it was possible to increase the number of appointments by 30 percent to the scheduling of the main clinic provider, maintaining the level of service provided. In addition, a new scheduling policy, called DOME CYCLE, was proposed, which has outperformed the other policies in the average of the tests performed.
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Martínez, Gustavo Enrique. "Frame work for Integrating Scheduling Policies into Workflow Engines." Doctoral thesis, Universitat Autònoma de Barcelona, 2011. http://hdl.handle.net/10803/79127.
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En este trabajo se ha desarrollado una nueva solución para la integración de políticas de planificación de workflows en sistemas gestores de workflows (workflow engines). SchedFlow es la solución propuesta e implementada, la cual Permite que un usuario final pueda utilizar la política de planificación que desee, ya sea esta estática o dinámica, sin necesidad de modificar el sistema gestor de workflow. Además SchedFlow toma en cuenta cuando una tarea del workflow no se puede ejecutar por eventos externos, como que una máquina está siendo utilizada por el usuario principal de la misma. En este tipo de escenarios SchedFlow realiza la replanificación de tareas, siempre bajo la política de planificación definida o elegida por el usuario. Como resultado se ha obtenido una aportación novedosa ya que normalmente si el usuario desea utilizar una política de planificación específica, deberá modificar el gestor de workflow para que soporte dicha política de planificación. Un punto importante a destacar, es que esta tesis además de contener un estudio exhaustivo de la bibliografía existente en el área, y de realizar un análisis de problema y diseño de solución propuesta, implementa la solución en un entorno oportunístico real. Los resultados de esta tesis para la planificación de workflows en entornos Grid, abre una nueva vía para el estudio de políticas de planificación para este tipo de aplicaciones, que será aprovechado por futuras investigaciones en la UAB.
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Malhotra, Manoj K. "Staff scheduling models and policies in postal distribution systems /." Connect to resource, 1990. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1266494783.
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Young, Laurie Robert. "Scheduling in a grid environment using high level policies." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426063.
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Malhotra, Manoj Kumar. "Staff scheduling models and policies in postal distribution systems." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1266494783.
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Shukla, Umesh Kumar. "Backpressure Policies for Wireless ad hoc Networks." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31982.
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Interference in ad hoc wireless networks causes the performance of traditional networking protocols to suffer. However, some user applications in ad hoc networks demand high throughput and low end-user delay. In the literature, the backpressure policy, i.e. queue backlog differential-based joint routing and scheduling, is known to be throughput-optimal with robust support for traffic load fluctuations \cite{Tssailus92}. Unfortunately, many backpressure-based algorithms cannot be implemented due to high end-user delay, inaccurate assumptions for interference, and high control overhead in distributed scenarios. We develop new backpressure based approaches to address these issues. We first propose a heuristic packet forwarding scheme that solves the issue of high end-user delay and still provides near-optimal throughput. Next we develop a novel interference model that provides simple yet accurate interference relationships among users. Such a model is helpful in designing a simple backpressure scheduling algorithm that does not violate realistic interference constraints. Finally we develop distributed backpressure algorithms based on our proposed ideas. Our distributed algorithms provide throughput performance close to the optimal and have low control overhead and simple implementation.Master of Science
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Schelle, Graham. "Runtime allocation and scheduling policies across network on chip architectures." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3288868.
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Tan, Chin Jiat. "Workload analysis and scheduling policies for a document processing centre." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/38286.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references.
This thesis is the result of a six-month internship at the Steel Stock Department of Keppel FELS Singapore, a company which is involved in the design and construction of oil-rigs. The primary objective of this project is to reduce the tardiness of the delivery of steel materials and identify the reasons behind the delay. The initial stage of this attachment is devoted to understanding the process flow of the department. Analysis has been done to pinpoint to the exact causes of the delay, which is at the stages of document processing and dispatching to the storage areas. The workload at each stage of document processing has been analyzed using a queuing model and it has been found that the stage that the issue vouchers have to be generated and printed out is the bottleneck in the entire process flow. Some recommendations have been proposed to alleviate the problem. The second part of this thesis focuses on the reasons why scheduling rules should be utilized when dispatching the issue vouchers to the storage areas. Three scheduling rules have been tested and their performances with regards to tardiness have been studied.
by Chin Jiat Tan.
M.Eng.
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MATERI, SERGIO. "Energy Efficient Policies, Scheduling, and Design for Sustainable Manufacturing Systems." Doctoral thesis, Università degli studi della Basilicata, 2022. http://hdl.handle.net/11563/155809.
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Climate mitigation, more stringent regulations, rising energy costs, and sustainable manufacturing are pushing researchers to focus on energy efficiency, energy flexibility, and implementation of renewable energy sources in manufacturing systems. This thesis aims to analyze the main works proposed regarding these hot topics, and to fill the gaps in the literature. First, a detailed literature review is proposed. Works regarding energy efficiency in different manufacturing levels, in the assembly line, energy saving policies, and the implementation of renewable energy sources are analyzed. Then, trying to fill the gaps in the literature, different topics are analyzed more in depth. In the single machine context, a mathematical model aiming to align the manufacturing power required to a renewable energy supply in order to obtain the maximum profit is developed. The model is applied to a single work center powered by the electric grid and by a photovoltaic system; afterwards, energy storage is also added to the power system. Analyzing the job shop context, switch off policies implementing workload approach and scheduling considering variable speed of the machines and power constraints are proposed. The direct and indirect workloads of the machines are considered to support the switch on/off decisions. A simulation model is developed to test the proposed policies compared to others presented in the literature. Regarding the job shop scheduling, a fixed and variable power constraints are considered, assuming the minimization of the makespan as the objective function. Studying the factory level, a mathematical model to design a flow line considering the possibility of using switch-off policies is developed. The design model for production lines includes a targeted imbalance among the workstations to allow for defined idle time. Finally, the main findings, results, and the future directions and challenges are presented.
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Joshi, Avinash. "Load Balancing, Queueing and Scheduling Mechanisms in Mobile Ad Hoc Networks." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1004447615.
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Thraves, Caro Christopher Brian. "Performance of Scheduling Policies and Networks in Generalizad Adversarial Queueing Models." Tesis, Universidad de Chile, 2008. http://www.repositorio.uchile.cl/handle/2250/103011.
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Esta tesis estudia problemas generados en redes de colas haciendo un an´alisis de
peor caso. Para esto se basa en un modelo de adversario llamado Adversarial Queueing
Theory (AQT). En esta tesis se presentan tres variantes de dicho modelo, cada una
enfocada al estudio de distintos problemas generados en redes de colas; problemas
motivados en redes de producci´on industriales o redes de comunicaci´on similares a
Internet. Adem´as se hace una contribuci´on directa a la versi´on continua del modelo
AQT llamado Continuous Adversarial Queueing Theory (CAQT).
El modelo de AQT tiene como principales componentes una red, un adversario y
una pol´ıtica. La red est´a representada por un grafo dirigido. El adversario inyecta
carga en la red, representada por paquetes, decidiendo el momento de inyecci´on,
punto de inyecci´on, camino que tiene que recorrer y destino de cada paquete, todo
esto en el momento de la inyecci´on. Cuando m´as de un paquete quiere cruzar un
arco al mismo, tiempo la pol´ıtica act´ua como criterio para determinar qu´e paquete
cruza primero, mientras que los paquetes restantes esperan en una cola asociada al
arco. Todo esto ocurre en un periodo arbitrariamente largo de tiempo. Para que el
adversario no sobrecargue la red trivialmente, ´este es acotado en base a la capacidad
de servicio de cada arco. Como par´ametro de buen comportamiento para pol´ıticas y
redes se define estabilidad, que de manera informal se puede entender como que es
la propiedad de que el n´umero de paquetes que todava no han llegado a destino est´e
acotado por una constante que no depende del tiempo.
En el primer modelo presentado se analizan redes de colas generadas en servidores.
En este modelo el adversario inyecta tareas representadas por un conjunto de procesos,
y en donde la dependencia entre todos los procesos de cada tarea est´a dada por una funci´on Booleana, que para cada proceso que depende del estado de los mismos.
De esta forma se da una condici´on suficiente para que dichas redes sean estables.
Un segundo modelo presentado, llamado AQT with setups, modela el problema
cuando el adversario puede inyectar paquetes de distinto tipo, y cada arco tiene que
pagar en tiempo de no trabajo cada vez que cambia el tipo de paquete que est´a
sirviendo. Como primer resultado se presentan la equivalencia entre una versi´on general
del modelo y una m´as restringida, lo que permite trabajar con la ´ultima sin perder
generalidad en t´erminos de estabilidad. Adem´as se caracteriza el conjunto de todas
las redes estables. En t´erminos de pol´ıticas, se demuestra la existencia de una red y
un adversario que impiden la existencia de pol´ıticas estables. Finalmente, se provee
de una variante de fluidos que permite ocupar herramientas externas para demostrar
estabilidad.
El aporte hecho a CAQT es la demostraci´on de estabilidad para el caso en que la red
es un anillo en una sola direcci´on. Adem´as, apoy´andose en el resultado ya probado
de estabilidad para grafos dirigidos sin ciclos, se caracteriza todo el conjunto de redes
estables.
El ´ultimo modelo presentado, llamado NSCAQT, asume que cada cola tiene un
reloj, hecho muy natural si se piensa que cada nodo es un computador y cada computador
tiene su propio reloj, y adem´as que dichos relojes no est´an sincronizados
necesariamente. De est´a forma, pol´ıticas que usan dicho reloj para tomar su decisi´on
pueden cambiar su funcionamiento con respecto al probado en el modelo de CAQT.
En este marco se demuestra que cuando los relojes pueden marcar horas distintas pero
la diferencia entre ellos no var´ıa, todas las pol´ıticas que son estables cuando todos los
relojes marcan la misma hora siguen siendo estables. Adem´as, para el caso en que las
diferencias entre los relojes puede variar pero de manera acotada, se presentan dos
familias de pol´ıticas estables que basan su decisi´on en el momento de inyecci´on de
cada paquete y alg´un par´ametro del camino que tienen que recorrer. Finalmente para
cuando los relojes no tienen cota para la diferencia entre ellos se presenta una nueva
pol´ıtica estable.
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Veatch, Michael H., and Lawrence M. Wein. "Scheduling a Make-To-Stock Queue: Index Policies and Hedging Points." Massachusetts Institute of Technology, Operations Research Center, 1992. http://hdl.handle.net/1721.1/5212.
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A single machine produces several different classes of items in a make-to-stock mode. We consider the problem of scheduling the machine to regulate finished goods inventory, minimizing holding and backorder or holding and lost sales costs. Demands are Poisson, service times are exponentially distributed, and there are no delays or costs associated with switching products. A scheduling policy dictates whether the machine is idle or busy, and specifies the job class to serve in the latter case. Since the optimal solution can only be numerically computed for problems with several products, our goal is to develop effective policies that are computationally tractable for a large number of products. We develop index policies to decide which class to serve, including Whittle's "restless bandit" index, which possesses a certain asymptotic optimality. Several idleness policies, which are characterized by hedging points, are derived, and the best policy is obtained from a heavy traffic diffusion approximation. Nine sample problems are considered in a numerical study, and the average suboptimality of the best policy is less than 3%.
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Pop, Traian. "Analysis and Optimisation of Distributed Embedded Systems with Heterogeneous Scheduling Policies." Doctoral thesis, Linköping : Department of Computer and Information Science, Linköpings universitet, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8934.
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Nham, John (John T. ). "Size-independent vs. size-dependent policies in scheduling heavy-tailed distributions." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45633.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 47-48).
We study the problem of scheduling jobs on a two-machine distributed server, where the job size distribution is heavy-tailed. We focus on two distributions, for which we prove that the performance of the optimal size-independent policy is asymptotically worse than that of a simple size-dependent policy. First, we consider a simple distribution where incoming jobs can only be of two possible sizes. The motivation is that with two largely different sizes, the simple distribution captures the important aspects of a heavy tail. Second, we extend to a bounded Pareto distribution, which has an actual heavy tail. For both cases, we analyze the performance with regards to slowdown (waiting time divided by job size) for several size-independent and size-dependent policies. We see that the size-dependent policies perform better, and then go on to prove that even the best size-independent policy cannot achieve the same performance. We conclude that as we increase the variance of our job size distribution, the gap between size-independent and size-dependent policies grows.
by John Nham.
M.Eng.
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Burgess, Kevin. "Stability and performance analysis of scheduling policies for flexible manufacturing systems /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487862972136559.
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Comşa, Ioan-Sorin. "Sustainable scheduling policies for radio access networks based on LTE technology." Thesis, University of Bedfordshire, 2014. http://hdl.handle.net/10547/584068.
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In the LTE access networks, the Radio Resource Management (RRM) is one of the most important modules which is responsible for handling the overall management of radio resources. The packet scheduler is a particular sub-module which assigns the existing radio resources to each user in order to deliver the requested services in the most efficient manner. Data packets are scheduled dynamically at every Transmission Time Interval (TTI), a time window used to take the user’s requests and to respond them accordingly. The scheduling procedure is conducted by using scheduling rules which select different users to be scheduled at each TTI based on some priority metrics. Various scheduling rules exist and they behave differently by balancing the scheduler performance in the direction imposed by one of the following objectives: increasing the system throughput, maintaining the user fairness, respecting the Guaranteed Bit Rate (GBR), Head of Line (HoL) packet delay, packet loss rate and queue stability requirements. Most of the static scheduling rules follow the sequential multi-objective optimization in the sense that when the first targeted objective is satisfied, then other objectives can be prioritized. When the targeted scheduling objective(s) can be satisfied at each TTI, the LTE scheduler is considered to be optimal or feasible. So, the scheduling performance depends on the exploited rule being focused on particular objectives. This study aims to increase the percentage of feasible TTIs for a given downlink transmission by applying a mixture of scheduling rules instead of using one discipline adopted across the entire scheduling session. Two types of optimization problems are proposed in this sense: Dynamic Scheduling Rule based Sequential Multi-Objective Optimization (DSR-SMOO) when the applied scheduling rules address the same objective and Dynamic Scheduling Rule based Concurrent Multi-Objective Optimization (DSR-CMOO) if the pool of rules addresses different scheduling objectives. The best way of solving such complex optimization problems is to adapt and to refine scheduling policies which are able to call different rules at each TTI based on the best matching scheduler conditions (states). The idea is to develop a set of non-linear functions which maps the scheduler state at each TTI in optimal distribution probabilities of selecting the best scheduling rule. Due to the multi-dimensional and continuous characteristics of the scheduler state space, the scheduling functions should be approximated. Moreover, the function approximations are learned through the interaction with the RRM environment. The Reinforcement Learning (RL) algorithms are used in this sense in order to evaluate and to refine the scheduling policies for the considered DSR-SMOO/CMOO optimization problems. The neural networks are used to train the non-linear mapping functions based on the interaction among the intelligent controller, the LTE packet scheduler and the RRM environment. In order to enhance the convergence in the feasible state and to reduce the scheduler state space dimension, meta-heuristic approaches are used for the channel statement aggregation. Simulation results show that the proposed aggregation scheme is able to outperform other heuristic methods. When the aggregation scheme of the channel statements is exploited, the proposed DSR-SMOO/CMOO problems focusing on different objectives which are solved by using various RL approaches are able to: increase the mean percentage of feasible TTIs, minimize the number of TTIs when the RL approaches punish the actions taken TTI-by-TTI, and minimize the variation of the performance indicators when different simulations are launched in parallel. This way, the obtained scheduling policies being focused on the multi-objective criteria are sustainable. Keywords: LTE, packet scheduling, scheduling rules, multi-objective optimization, reinforcement learning, channel, aggregation, scheduling policies, sustainable.
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Latta, Peter James. "A comparison of six repair scheduling policies for the P-3 aircraft." Thesis, Monterey, California. Naval Postgraduate School, 1988. http://hdl.handle.net/10945/22958.
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There are a finite number of identical aircraft each of which contain a number of different types of components which contain a number of different types of components which fail at different rates. In order for an aircraft to be operational, all of its components must be operational. Each component type has a finite number of spares. Failed components are repaired at a single server facility. Simulation is used to study the effect of 6 different repair scheduling policies. The repair policies are compared on the basis of average number of operating aircraft at the end of a mission period of one week. It is found that a repair policy which first repairs the component of the type with the fewest operating components is the best. In particular, it is much better than first-in, first-out and also may well improve upon a policy that serves the longest waiting line first. A simple spares stockage policy is developed and evaluated when the above scheduling policy is in use. Keywords: P-3 aircraft; Repair scheduling; Queuing models; Simulation; Patrol aircraft, Theses
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Qian, Zhenzhi. "Designing High Performance Scheduling Policies in Multi-channel and Multi-antenna Networks." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555629597648426.
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Lira, Bonates Eduardo Jorge. "Analysis of truckshovel dispatching policies using computer simulation." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65406.
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Geldhauser, Holly A. "Income, scheduling flexibility, and diversity policies an experimental investigation of recruiting older workers /." Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1181668141/.
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Miehling, Erik J. "Stochastic target scheduling for radar resource management : threat assessment and optimal threshold policies." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/37417.
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This thesis formulates a stochastic scheduler for use in adaptive resource management of a single Ground Moving Target Indicator (GMTI) radar when faced with tracking multiple, weakly maneuvering targets. The general problem involves first determining a priority allocation of the L targets, then determining the optimal time to spend using the specified allocation. We present a framework for computing the threat estimate and associated priority of each target in a surveillance environment, termed the radar macro-manager. The threat level of each target is computed based on its heading and proximity relative to a set of user-specified static assets. We present a weight assignment algorithm based on the geography of the surveillance region and use eigenvector centrality to assign vulnerability weights to each asset. The error in the threat level is computed based on the error-covariance matrix of each target, provided by a Kalman filter. Both the threat level and threat error are used to compute the respective priority rank distributions. From the priority distributions of each target we specify a queue of tasks to maximize a reward function associated with processing the queue. The queue is determined with the aid of structural results from the field of optimal issuing which involves ordering the priority rank distributions with respect to the monotone likelihood ratio. In particular, we compute an optimal queue which specifies the order in which we observe individual targets. The length of each target observation is controlled by an external stochastic process, termed the radar micro-manager. The problem of determining this optimal stopping time is formulated as a sequential decision process, a type of Markov decision process. We provide conditions such that the optimal policy is characterized by a monotone threshold policy on the partially ordered set of positive definite error covariance matrices of each target. Given that the optimal policy is monotone, we can efficiently approximate its form with an affine hyperplane using a hybrid random search - Simultaneous Perturbation Stochastic Approximation (SPSA) algorithm. Detailed numerical simulations evaluate the performance of both the radar macro-manager and radar micro-manager.
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Sethi, Suresh P., Gerhard Sorger, and Xun Yu Zhou. "Stability of real-time lot-scheduling and machine replacement policies with quality levels." SFB Adaptive Information Systems and Modelling in Economics and Management Science, WU Vienna University of Economics and Business, 1999. http://epub.wu.ac.at/988/1/document.pdf.
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In this note we show how the main result of Lou et al. can be generalized to an unreliable machine with various quality levels. We consider a single machine which can process parts of different types. The machine can process at most one part at a time and it needs a setup period whenever it switches from one part-type to another. Parts enter the system in type-specific input rates and require type-specific processing times. The quality of the machine deteriorates according to a continuous-time Markov process and the only way to improve the quality is by replacing the machine by a new one. We postulate a simple form of real-time replacement and scheduling policies, and derive conditions ensuring the stability of the system under these policies. (author's abstract)Series: Working Papers SFB "Adaptive Information Systems and Modelling in Economics and Management Science"
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Al-Qaseer, Firas Abdulmajeed. "Scheduling policies considering both production duration and energy consumption criteria for environmental management." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC028/document.
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Nous présentons les enjeux du management environnemental et soulignons l’importance d’une politique d’économie d’énergie pour les entreprises. Nous proposons un modèle pour déterminer le bilan énergétique de la fabrication en intégrant les différentes phases productives et non-productives. Nous définissons un double objectif pour la minimisation de la durée de production et de la consommation d’énergie. Nous appliquons ce modèle à l’ordonnancement d’ateliers job-shop flexibles. Pour déterminer la solution optimale nous utilisons deux classes de méthodes : - La première relève des algorithmes génétiques. Nous proposons différents types d’algorithmes pour résoudre ce problème multicritère. Nous proposons par exemple de faire évoluer deux populations pour minimiser respectivement l’énergie consommée et la durée de production et de les croiser pour atteindre l’objectif global. - La seconde relève de la programmation sous contrainte. Nous proposons de rechercher la solution optimale en développant une double arborescence pour évaluer l’énergie consommée et la durée de production. Nous construisons notre algorithme en partant des tâches à réaliser sur les machines ou en partant des machines qui réaliseront les tâches. Nous discutons de la construction du front de Pareto pour l’obtention de la meilleure solution.Nous terminons en comparant les différentes approches et en discutant leur pertinence pour traiter des problèmes de différentes tailles. Nous proposons également plusieurs améliorations et quelques pistes pour de futures recherchesWe present the challenges of environmental management and underline the importance of an energy saving policy for companies. We propose a model to determine the energy balance of manufacturing by integrating the different productive and non-productive phases. We define two purposes for minimizing production time and energy consumption. We apply this model to the scheduling of flexible job-shop workshops. To determine the optimal solution we use two types of methods: - The first is genetic algorithms. We propose different types of algorithms to solve this multi-criteria problem. For example, we propose to develop two populations to minimize the energy consumed and the production time, and to cross them to achieve the overall objective. - The second is constraint programming. We propose to find the optimal solution by developing a double tree to evaluate the energy consumed and the production time. We build our algorithm starting from the tasks to be performed on the machines or from the machines that will perform the tasks. We discuss the construction of the Pareto front to get the best solution.We finish by comparing the different approaches and discussing their relevance to deal with problems of different sizes. We also offer several improvements and some leads for future research
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Marinakis, Theodoros. "ENHANCING FAIRNESS AND PERFORMANCE ON CHIP MULTI-PROCESSOR PLATFORMS WITH CONTENTION-AWARE SCHEDULING POLICIES." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/dissertations/1757.
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Chip Multi-Processor (CMP) platforms, well-established in the server, desktop and embedded domain, succeeded in overcoming the power consumption and heat dissipation bottlenecks by integrating multiple cores, less complex and powerful than their single-core ancestors, in a single die. A major issue induced by the design of the CMPs is contention for the shared resources of the platform, Last Level Cache (LLC) and main memory bandwidth. Applications, running concurrently on the cores, compete with each other for the shared resources, and are subject to performance degradation. The way applications are assigned to the CMP, is crucial for the overall performance of the system. A scheduling policy that accounts for contention will bring high performance speed-ups, whereas an agnostic one will generate unpredictable contention conditions. For this reason the significance of the scheduler has been elevated, as it is the component that determines which applications utilize the resources each time period.In this thesis, we address cross-core interference on CMP platforms, by designing scheduling policies that improve performance and fairness. We deal with contention in three ways. In our first approach, we incorporate the notion of progress in order to balance unfairness among the applications of the workload. Performance degradation is not evenly distributed and progress greatly varies among them. In order to provide a fair execution environment, we monitor, at run-time, applications assigned to the CPU and prioritize them based on the extent at which they are affected by contention.In our second approach, we target performance by mitigating contention on shared resources. It is necessary to decide, out of all the possible application schedules, the one that generates the least amount of resource interference. To achieve that, the first indispensable step is to extract an interference profile for the applications executed on the CMP. We accomplish that by applying pressure to all levels of memory hierarchy and identifying the point at which performance is compromised. From our analysis, we understand that shared resources can tolerate pressure of certain amount; applications can be grouped together if the overall generated pressure does not reach the saturation point of the shared resources. Having extracted this information, we proceed to the placement of the application in such a way that overall resource requirements are as balanced as possible across the execution.Finally, we design a policy in order to improve performance and fairness at the same time. Applications that heavily rely on the LLC are separated from those with high main memory bandwidth, in order to avoid the destructive effects caused by the LLC thrashing behavior of the latter. The group executed on the CPU is determined based on the key observation that the overall requirements of the group should not exceed the saturation limits of the CMP. Additionally, during execution, the progress for each application is estimated and those with the least accumulated progress are prioritized.Our proposed policies are evaluated in an Intel Xeon E5-2620 v3 processor. A variety of benchmark suites were utilized to generate mixes of diverse characteristics. Our methodologies are implemented in user-space and can be deployed on Linux-based systems. Experimental results show the benefits of tackling contention in shared resources. We achieve throughput gains of up to 16% and unfairness is reduced by 2.37x on average compared to Linux scheduler.
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Katre, Kedar Maheshwar. "Policies for Migration of Real-Time tasks in Embedded Multicore Systems." OpenSIUC, 2010. https://opensiuc.lib.siu.edu/theses/264.
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There has been a lot of work that has been done on timing predictability of real-time tasks on embedded systems. The main assumption in these studies has been that the timing behavior has been based on single processor systems. The scenario has changed entirely when the single core systems have been replaced with the new Multicore systems. The timing predictability is controlled by the migrating tasks, the network topology connecting the cores and the number of cores on the system. In this thesis we come up with a feasibility analysis which depends on the characteristics of the tasks viz. number of cache lines, time of migration, available bandwith, number of tasks etc. We also test this analysis on novel mechanisms of migration which have been proposed recently and present its results.
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Markowitz, David Maxwell. "A unified approach to single machine scheduling : heavy traffic analysis of dynamic cyclic policies." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/11040.
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Peters, Christopher Nectarios. "Performance analysis of scheduling policies for a class of flexible automated manufacturing systems through simulation." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38765.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.Includes bibliographical references (p. 165).
by Christopher Nectarios Peters.
M.S.
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Yong, Meow Seen 1977. "Simulation of real-time scheduling policies in multi-product, make-to-order semiconductor fabrication facilities." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/89311.
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Au, Terrence Siu-Lun Carleton University Dissertation Computer Science. "Characterization of classes of parallel programs and their use in performance evaluation of scheduling policies." Ottawa, 1992.
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Villegas, David. "Interoperable Resource Brokering with Policy-based Provisioning and Job Allocation." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/788.
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The increasing needs for computational power in areas such as weather simulation, genomics or Internet applications have led to sharing of geographically distributed and heterogeneous resources from commercial data centers and scientific institutions. Research in the areas of utility, grid and cloud computing, together with improvements in network and hardware virtualization has resulted in methods to locate and use resources to rapidly provision virtual environments in a flexible manner, while lowering costs for consumers and providers.
However, there is still a lack of methodologies to enable efficient and seamless sharing of resources among institutions. In this work, we concentrate in the problem of executing parallel scientific applications across distributed resources belonging to separate organizations. Our approach can be divided in three main points. First, we define and implement an interoperable grid protocol to distribute job workloads among partners with different middleware and execution resources. Second, we research and implement different policies for virtual resource provisioning and job-to-resource allocation, taking advantage of their cooperation to improve execution cost and performance. Third, we explore the consequences of on-demand provisioning and allocation in the problem of site-selection for the execution of parallel workloads, and propose new strategies to reduce job slowdown and overall cost.
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Meng, Kai M. Eng Massachusetts Institute of Technology. "Reduce cycle time and work in process in a medical device factory : scheduling policies for needle assembly machine." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42328.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (p. 58).
Many manufacturing firms have improved their operations by implementing a work-in-process (WIP) limiting control strategy. This project explores the application of this concept to limit WIP and reduce cycle time for the Becton, Dickinson and Company's manufacturing facility in Tuas, Singapore. BD's Eclipse Safety Needle production line is facing increasing pressure to reduce its high WIP and long cycle times. With the forecast of increasing demand, the current production control practice will sooner or later push the shop floor space to a limit. We divided the overall system into three manageable sub-systems and analyzed different strategies for each. At Needle Assembly machine (AN) and downstream, we can achieve significant reduction in cycle time and work in process by eliminating the unnecessary early start of production and extra delay caused by the current planning method, and by reducing the transfer batch sizes. In this paper, we refine further these approaches to AN and packaging machines with consideration of a mixed dispatching rule and a CONWIP release rule. The mixed dispatching rule reduces WIP level of the system by enhancing the total throughput of the four production routes after the bottleneck (AN machine). The CONWIP release rule further reduces WIP by controlling the total amount of inventory in the system. With these four proposed strategies, we can have a pure pull system within AN and downstream machines and achieve significant reduction in cycle time and WIP.
by Kai Meng.
M.Eng.
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Johnstone, Daniel P. "Integrated retrograde, repair scheduling, and distribution policies in a multi-echelon service parts supply network with multiple repair depots." [Bloomington, Ind.] : Indiana University, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3380089.
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Thesis (Ph.D.)--Indiana University, Kelley School of Business, 2009.Title from PDF t.p. (viewed on Jul 19, 2010). Source: Dissertation Abstracts International, Volume: 70-12, Section: B, page: 7834. Adviser: S. Christian Albright.
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Roychowdhury, Sayak. "Data-Driven Policies for Manufacturing Systems and Cyber Vulnerability Maintenance." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1493905616531091.
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Besson, Thomas 1972. "Simulation modeling as a tool for assessing the impact of inventory control and scheduling policies in the manufacturing of specialty steel." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50405.
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Broberg, James Andrew, and james@broberg com au. "Effective task assignment strategies for distributed systems under highly variable workloads." RMIT University. Computer Science and Information Technology, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080130.150130.
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Heavy-tailed workload distributions are commonly experienced in many areas of distributed computing. Such workloads are highly variable, where a small number of very large tasks make up a large proportion of the workload, making the load very hard to distribute effectively. Traditional task assignment policies are ineffective under these conditions as they were formulated based on the assumption of an exponentially distributed workload. Size-based task assignment policies have been proposed to handle heavy-tailed workloads, but their applications are limited by their static nature and assumption of prior knowledge of a task's service requirement. This thesis analyses existing approaches to load distribution under heavy-tailed workloads, and presents a new generalised task assignment policy that significantly improves performance for many distributed applications, by intelligently addressing the negative effects on performance that highly variable workloads cause. Many problems associated with the modelling and optimisations of systems under highly variable workloads were then addressed by a novel technique that approximated these workloads with simpler mathematical representations, without losing any of their pertinent original properties. Finally, we obtain advance queuing metrics (such as the variance of key measurements like waiting time and slowdown that are difficult to obtain analytically) through rigorous simulation.
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Lee, Moonsu. "Analytical models to evaluate system performance measures for vehicle based material-handling systems under various dispatching policies." Diss., Texas A&M University, 2005. http://txspace.tamu.edu/bitstream/handle/1969.1/2352/etd-tamu-2005A-INEN-Lee.pdf?sequence=1.
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Reis, Valéria Quadros dos. "Escalonamento em grids computacionais: estudo de caso." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-18092006-115903/.
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Esta dissertação tem por objetivo apresentar a proposta de uma política de escalonamento para grids computacionais. Essa política, intitulada Dynamic Max-Min2x, é orientada ao escalonamento de aplicações cujas tarefas não realizam comunicação entre si e visa a redução do tempo de resposta dessas aplicações através da utilização de atribuição dinâmica de tarefas e replicação das mesmas. Experimentos, feitos através de simulação, mostram que o tempo médio de resposta de aplicações utilizando-se a Dynamic Max-Min2x é inferior ao de outras políticas da literatura. Análises dos resultados desses experimentos apontam que esse tempo tende a ser mais atrativo principalmente quando as tarefas necessitam de muito processamento e quando há grande variação de carga no sistema, caracteristicas comuns em grids computacionais. Além disso, esta dissertação apresenta a implementação de um framework utilizando-se o Globus Toolkit, onde é possível a inserção de políticas de escalonamento para a submissão inteligente de tarefas em um grid computacional.This Master thesis proposes a new grid scheduling policy called Dynamic Max-Min2x. This policy focuses on applications in which tasks do not communicate among themsenves and targets a response time reduction of these applications through the use of dynamic task distribution and replication techniques. Experiments, done using simulations, have shown that the response time related to Dynamic Max-Min2x is smaller than others policies found in literature. Analysis of the results have demonstrated that this time tends to become more attractive when tasks do not need much processing power and when there is a great load variation in the system, characteristics frequently found in grids. Furthermore, this thesis presents the implementation of a framework using Globus Toolkit, which makes possible the new scheduling policies insertion to provide an intelligent submission tasks in a computational grid system.
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Oliveira, Juliano Amorim de. "Um estudo comparativo de cargas de trabalho e políticas de escalonamento para aplicações paralelas em clusters e grids computacionais." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-12012007-143257/.
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Diversas políticas de escalonamento para aplicações paralelas voltadas a ambientes computacionais distribuídos têm sido propostas. Embora tais políticas apresentem bons resultados, elas são, geralmente, avaliadas em cenários específicos. Quando o cenário muda, com diferentes ambientes distribuídos e condições de carga, essas políticas podem ter seu desempenho deteriorado. Nesse contexto, este trabalho apresenta um estudo comparativo envolvendo dez políticas de escalonamento avaliadas em diferentes cenários. Cada uma das políticas foi submetida a uma combinação de quatro cargas de trabalho de ocupação da UCP e três variações da taxa de comunicação média entre os processos, utilizando a rede. Foram considerados ainda três sistemas distribuídos distintos: dois clusters, com diferentes quantidades de nós, e um grid computacional. Foi utilizada a simulação com ambientes próximos ao real e cargas de trabalho obtidas de modelos realísticos. Os resultados demonstraram que, embora as políticas sejam voltadas a ambientes computacionais paralelos e distribuídos, quando o cenário muda, o desempenho cai e a ordem de classificação entre as políticas se altera. Os resultados permitiram ainda demonstrar a necessidade de se considerar a comunicação entre os processos durante o escalonamento em grids computacionais.Several scheduling policies for parallel applications directed to the distributed computational environments have been proposed. Although such policies present good results, they, generally, are evaluated in specific scenarios. When scenario change, by using different distributed environments and workload conditions, these policies can have its performance spoiled. In this context, this work presents a comparative study involving ten scheduling policies evaluated on different scenarios. Each policy was submitted to a combination of four CPU occupation workloads and three variations of interprocess average communication rates, using the network. Three different distributed systems had been yet considered: two clusters, with different amounts of nodes, and one grid computing. Simulation was used with environments near to the real and workloads obtained of realistic models. Although the policies are directed to parallel and distributed environments, the results have demonstrated that when scenario change, the performance falls and the ranking between the policies changes too. The results have still allowed to demonstrate the necessity of considering interprocess communication during the scheduling in a grid computing.
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Zambelli, Monica de Souza. "Planejamento da operação energetica via curvas-guias de armazenamento." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259877.
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Orientadores: Secundino Soares Filho, Marcelo Agusto CicognaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: O setor elétrico brasileiro vem passando por sucessivas reformas na busca por um modelo institucional que permita a otimização do uso dos recursos energéticos, conciliada com o objetivo de se alcançar um desenvolvimento sustentável. O planejamento energético tem um papel fundamental neste contexto, de modo que estudos e pesquisas que forneçam suporte ao planejamento do setor energético e à elaboração de políticas energéticas de médio e longo prazo têm ganhado destaque entre as prioridades do setor elétrico brasileiro. A proposta deste trabalho é apresentar uma política operativa baseada no conceito de curvas-guias de armazenamento para o planejamento da operação energética de médio prazo. Essa política determina que, a cada estágio do período de planejamento, as decisões de vazão turbinada por cada usina hidrelétrica devem ser tais que mantenham seus reservatórios em níveis pré-estabelecidos por curvas-guias de armazenamento. A análise de desempenho dessa política operativa foi feita através de simulações da operação hidrotérmica, para sistemas de único reservatório e uma cascata do sistema elétrico brasileiro. Os resultados das simulações foram também comparados aos de políticas operativas mais robustas, incluindo o uso de programação dinâmica estocástica, técnica de solução já consolidada para o problema e utilizada atualmente no setor elétrico brasileiro. Os resultados demonstram que, apesar de simples e transparente, essa política operativa apresenta um desempenho competitivo para o planejamento da operação energética
Abstract: The Brazilian electric sector has been passing through successive reforms in the search for an institutional model that allows the optimization of the use of the energetic resources, concealed with the goal of achieving a sustaining development. The energetic planning plays a fundamental roll in this context, thus studies and researches designated to support planning in the energetic sector and elaboration of long term energetic policies have been gaining space among the Brazilian electric sector priorities. The proposal of this work is to present an operating policy based on the concept of storage guide-curves for the mid term hydrothermal scheduling. This policy determines that, at each stage of the planning period, the decisions of water discharged from each hydro plant must be such that keep their reservoirs at levels pre-determined by storage guide-curves. The performance analysis of this operating policy was done through operation simulation, considering different hydro plants of the Brazilian system. The simulation results were also compared to more robust operative policies, including the use of stochastic dynamic programming, a consolidated solution technique for the problem witch is actually in use by the Brazilian electric sector. The results demonstrate that, despite of simple and transparent, this operating policy presents a competitive performance for the hydrothermal scheduling
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica
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Mallangi, Siva Sai Reddy. "Low-Power Policies Based on DVFS for the MUSEIC v2 System-on-Chip." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-229443.
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Multi functional health monitoring wearable devices are quite prominent these days. Usually these devices are battery-operated and consequently are limited by their battery life (from few hours to a few weeks depending on the application). Of late, it was realized that these devices, which are currently being operated at fixed voltage and frequency, are capable of operating at multiple voltages and frequencies. By switching these voltages and frequencies to lower values based upon power requirements, these devices can achieve tremendous benefits in the form of energy savings. Dynamic Voltage and Frequency Scaling (DVFS) techniques have proven to be handy in this situation for an efficient trade-off between energy and timely behavior. Within imec, wearable devices make use of the indigenously developed MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). This system is optimized for efficient and accurate collection, processing, and transfer of data from multiple (health) sensors. MUSEIC v2 has limited means in controlling the voltage and frequency dynamically. In this thesis we explore how traditional DVFS techniques can be applied to the MUSEIC v2. Experiments were conducted to find out the optimum power modes to efficiently operate and also to scale up-down the supply voltage and frequency. Considering the overhead caused when switching voltage and frequency, transition analysis was also done. Real-time and non real-time benchmarks were implemented based on these techniques and their performance results were obtained and analyzed. In this process, several state of the art scheduling algorithms and scaling techniques were reviewed in identifying a suitable technique. Using our proposed scaling technique implementation, we have achieved 86.95% power reduction in average, in contrast to the conventional way of the MUSEIC v2 chip’s processor operating at a fixed voltage and frequency. Techniques that include light sleep and deep sleep mode were also studied and implemented, which tested the system’s capability in accommodating Dynamic Power Management (DPM) techniques that can achieve greater benefits. A novel approach for implementing the deep sleep mechanism was also proposed and found that it can obtain up to 71.54% power savings, when compared to a traditional way of executing deep sleep mode.Nuförtiden så har multifunktionella bärbara hälsoenheter fått en betydande roll. Dessa enheter drivs vanligtvis av batterier och är därför begränsade av batteritiden (från ett par timmar till ett par veckor beroende på tillämpningen). På senaste tiden har det framkommit att dessa enheter som används vid en fast spänning och frekvens kan användas vid flera spänningar och frekvenser. Genom att byta till lägre spänning och frekvens på grund av effektbehov så kan enheterna få enorma fördelar när det kommer till energibesparing. Dynamisk skalning av spänning och frekvens-tekniker (såkallad Dynamic Voltage and Frequency Scaling, DVFS) har visat sig vara användbara i detta sammanhang för en effektiv avvägning mellan energi och beteende. Hos Imec så använder sig bärbara enheter av den internt utvecklade MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). Systemet är optimerat för effektiv och korrekt insamling, bearbetning och överföring av data från flera (hälso) sensorer. MUSEIC v2 har begränsad möjlighet att styra spänningen och frekvensen dynamiskt. I detta examensarbete undersöker vi hur traditionella DVFS-tekniker kan appliceras på MUSEIC v2. Experiment utfördes för att ta reda på de optimala effektlägena och för att effektivt kunna styra och även skala upp matningsspänningen och frekvensen. Eftersom att ”overhead” skapades vid växling av spänning och frekvens gjordes också en övergångsanalys. Realtidsoch icke-realtidskalkyler genomfördes baserat på dessa tekniker och resultaten sammanställdes och analyserades. I denna process granskades flera toppmoderna schemaläggningsalgoritmer och skalningstekniker för att hitta en lämplig teknik. Genom att använda vår föreslagna skalningsteknikimplementering har vi uppnått 86,95% effektreduktion i jämförelse med det konventionella sättet att MUSEIC v2-chipets processor arbetar med en fast spänning och frekvens. Tekniker som inkluderar lätt sömn och djupt sömnläge studerades och implementerades, vilket testade systemets förmåga att tillgodose DPM-tekniker (Dynamic Power Management) som kan uppnå ännu större fördelar. En ny metod för att genomföra den djupa sömnmekanismen föreslogs också och enligt erhållna resultat så kan den ge upp till 71,54% lägre energiförbrukning jämfört med det traditionella sättet att implementera djupt sömnläge.
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Lee, Tzu-En. "A study and analysis of a transmission scheduling and discard algorithm for ATM networks." Thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-03172010-020744/.
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Wang, Jianfu. "Scheduling Policies in Service Networks." Thesis, 2014. http://hdl.handle.net/1807/65765.
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In this thesis, we study different scheduling policies in service networks. In Chapter 2, we consider two service level (SL) measures in a two-server tandem queue system: the average sojourn time and the probability of long waits. We demonstrate that a family of Threshold Based Policies (TBP) can reduce the probability of long waits while maintaining sojourn times that are only slightly higher than those of a non-idling policy. In Chapter 3, we present a case study for improving the operations of a healthcare provider that has an open-shop queueing network. We propose an effective implementation of Dynamic Scheduling Policies (DSPs) and a generalized TBP to improve the SL in an open-shop queueing networks. Using a simulation model we demonstrate that an open-shop queueing network can be managed in a systematic fashion to deliver improved SL. In Chapter 4, we study the waiting time distribution of two different priority classes in an M/M/c queue with different service times. For the c=2 case, we provide closed form expression of the Generating Function (GF) of the number of low-priority jobs in the system, which can lead to the waiting time distribution. For c>2 case, we present an efficient numerical algorithm for deriving this GF. We discuss several insights gained from numerical results.
Both Chapter 2 and 3 were supervised by Professors Opher Baron, Oded Berman, and Dmitry Krass. Chapter 4 was supervised by Professors Opher Baron and Alan Scheller-Wolf.
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Stuecheli, Jeffrey Adam. "Mitigating DRAM complexities through coordinated scheduling policies." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-05-2762.
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Contemporary DRAM systems have maintained impressive scaling by managing a careful balance between performance, power, and storage density. In achieving these goals, a significant sacrifice has been made in DRAM's operational complexity. To realize good performance, systems must properly manage the significant number of structural and timing restrictions of the DRAM devices. DRAM's efficient use is further complicated in many-core systems where the memory interface has to be shared among multiple cores/threads competing for memory bandwidth. In computer architecture, caches have primarily been viewed as a means to hide memory latency from the CPU. Cache policies have focused on anticipating the CPU's data needs, and are mostly oblivious to the main memory. This work demonstrates that the era of many-core architectures has created new main memory bottlenecks, and mandates a new approach: coordination of cache policy with main memory characteristics. Using the cache for memory optimization purposes dramatically expands the memory controller's visibility of processor behavior, at low implementation overhead. Through memory-centric modification of existing policies, such as scheduled writebacks, this work demonstrates that performance-limiting effects of highly-threaded architectures combined with complex DRAM operation can be overcome. This work shows that an awareness of the physical main memory layout and by focusing on writes, both read and write average latency can be shortened, memory power reduced, and overall system performance improved. The use of the "Page-Mode" feature of DRAM devices can mitigate many DRAM constraints. Current open-page policies attempt to garner the highest level of page hits. In an effort to achieve this, such greedy schemes map sequential address sequences to a single DRAM resource. This non-uniform resource usage pattern introduces high levels of conflict when multiple workloads in a many-core system map to the same set of resources. This work presents a scheme that provides a careful balance between the benefits (increased performance and decreased power), and the detractors (unfairness) of page-mode accesses. In the proposed Minimalist approach, the system targets "just enough" page-mode accesses to garner page-mode benefits, avoiding system unfairness. This is accomplished with the use of a fair memory hashing scheme to control the maximum number of page mode hits. High density memory is becoming ever more important as many execution streams are consolidated onto single chip many-core processors. DRAM is ubiquitous as a main memory technology, but while DRAM's per-chip density and frequency continue to scale, the time required to refresh its dynamic cells has grown at an alarming rate. This work shows how currently-employed methods to schedule refresh operations are ineffective in mitigating the significant performance degradation caused by longer refresh times. Current approaches are deficient -- they do not effectively exploit the flexibility of DRAMs to postpone refresh operations. This work proposes dynamically reconfigurable predictive mechanisms that exploit the full dynamic range allowed in the industry standard DRAM memory specifications. The proposed mechanisms are shown to mitigate much of the penalties seen with dense DRAM devices. In summary this work presents a significant improvement in the ability to exploit the capabilities of high density, high frequency, DRAM devices in a many-core environment. This is accomplished though coordination of previously disparate system components, exploiting integration of such components into highly integrated system designs.text
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Liu, Chang. "Scheduling policies for disks and disk arrays." Thesis, 2005. http://library1.njit.edu/etd/fromwebvoyage.cfm?id=njit-etd2005-079.
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Mansharamani, Rajesh Kishin. "Efficient analysis of parallel processor scheduling policies." 1993. http://catalog.hathitrust.org/api/volumes/oclc/31353011.html.
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Thesis (Ph. D.)--University of Wisconsin--Madison, 1993.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 238-248).