Auswahl der wissenschaftlichen Literatur zum Thema „Distributed process simulation“

Co-simulation techniques have evolved significantly over the last 10 years. System simulation and hardware-in-the-loop testing are used to develop innovative products in many industrial sectors. Despite the success of these simulation techniques, their efficient application requires a systematic approach. In practice the integration and coupling of heterogeneous systems still require enormous efforts. At this point in time no unified process for integration and simulation of DCP-based co-simulation scenarios is available. In this article we present ProMECoS, a process model for efficient, standard-driven distributed co-simulation. It defines the necessary tasks required to prepare, instantiate and execute distributed co-simulations according to the DCP standard. Furthermore, it enables the exploitation of front-loading benefits, thus reducing the overall system development effort. ProMECoS is based on the IEEE 1730 standard for Distributed Simulation Engineering and Execution Process. It adopts the artefacts of the DCP specification, and defines additional process artefacts. The DCP specification and its associated default integration methodology were developed by a balanced consortium in context of the ITEA 3 project ACOSAR. The DCP is compatible to the well-adopted FMI standard. Therefore both standards can be used together for seamless development using models, software, and real components. ProMECoS provides the necessary guidance for efficient product development and testing.

Abstract In our paper, we designed a distributed feedback control law for a fluid heating model, which is described by a one-dimensional first-order hyperbolic equation. This equation has a non-local boundary condition with time-delay terms. Further, according to geometric control theory, the distributed feedback control law ensures the exponential stability and the input-output stability in a closed-loop system. Finally, we evaluate the proposed controller performances by solving tracking and disturbance rejection problems through numerical simulation, and we compare the simulation results with the optimal control method.

The points of a graph G will form clusters as a result of a flow process. Initially, points i of G own resources xi which are i.i.d. random real numbers. Afterwards, resources flow between points, but always from a point to a neighbor that has accumulated a larger total resource. Thus points with small resource tend to lose it and points with large resource tend to gain. Eventually the flow stops with only two kinds of points, nulls with no resource left and absorbers with such large resource that no neighbor can take it. The final resource at an absorber is a sum of certain initial resources xi, and the corresponding points i form one cluster. Analytical results are obtainable when G is the chain of integer points on the line. Probability distributions are derived for the distance between consecutive absorbers and the size of a cluster. Indeed these distributions do not involve the given distribution for the xi. The Laplace transform of the distribution of final resources at absorbers is derived but the distribution itself is obtained by a simulation. For general graphs G only partial results are obtained.

The points of a graph G will form clusters as a result of a flow process. Initially, points i of G own resources xi which are i.i.d. random real numbers. Afterwards, resources flow between points, but always from a point to a neighbor that has accumulated a larger total resource. Thus points with small resource tend to lose it and points with large resource tend to gain. Eventually the flow stops with only two kinds of points, nulls with no resource left and absorbers with such large resource that no neighbor can take it. The final resource at an absorber is a sum of certain initial resources xi , and the corresponding points i form one cluster. Analytical results are obtainable when G is the chain of integer points on the line. Probability distributions are derived for the distance between consecutive absorbers and the size of a cluster. Indeed these distributions do not involve the given distribution for the xi. The Laplace transform of the distribution of final resources at absorbers is derived but the distribution itself is obtained by a simulation. For general graphs G only partial results are obtained.

La combinaison d’automates cellulaires (CA) et de systèmes distribués offre un moyen simple de modéliser les problèmes environnementaux et sociaux en divisant les zones d’intérêt en segments spatiales discrètes pour le calcul parallèle. L’évolution de l’état de chaque segment est divisée en étapes temporelles discrètes. Les divisions géographiques en tant qu’espace cellulaire irrégulier permettent de tirer parti des données ouvertes pour alimenter les systèmes de simulation. Les données sont analysées pour en déduire les règles de transition apportant des influences distribuées dans un quartier. Une étude de cas de modélisation de la propagation épidémique basée sur les divisions administratives est présentée. Étant donné l’hypothèse que l’épidémie se propage aux personnes vivant dans le quartier, un système de simulation est généré en fonction des voisins adjacents avec des conditions initiales de collecte à partir du portail de données ouvertes du gouvernement. Une approche hybride est introduite avec la coopération entre les tuiles régulières et les espaces cellulaires irréguliers dans la modélisation des activités côtières. Une simulation environnementale est nécessaire pour représenter les caractéristiques du sol et de la mer qui se propagent dans les deux espaces. Ces caractéristiques sont très différentes en raison de la capacité et de la réaction du sol, et du comportement de la mer, en particulier les courants et les marées. Le problème des marées vertes est modélisé lorsque les nutriments sont présents en concentrations élevées et piégés par les courants de marée
The combination of Cellular automata (CA) and distributed systems provide a simple way to model environmental and social issues by dividing the relevant areas into discrete spatial segments for parallel computation. The state evolution of each segment is divided into discrete time steps. Geographic divisions as irregular cell space give a chance to take advantage of Open Data in feeding the simulation systems. Data are analyzed to deduce the transition rules bringing distributed influences in a neighborhood. A case study of epidemic propagation modeling based on geographic divisions is presented. Given an assumption that the epidemic is spreading to people living in the neighborhood, a simulation system is generated based on adjacent neighbors with initial conditions collected from the government open data portal. A hybrid approach is introduced with the cooperation between regular tiles and irregular cellspaces in modeling shore activities. Environmental simulation is needed to represent ground and sea characteristics modeling spreading occurring on both spaces. These characteristics are very different due to soil capability and reaction, and sea behavior, in particular currents and tides. The problem of green tides is modeled when nutrients arepresented in high concentrations and entrapped by tidal currents

The increases in complexity of industrial process simulations necessitate faster methods and more accurate models for analysis. In many cases automation of industrial plants using real-time control cannot be solved using present computer methodologies. This thesis introduces a parallel methodology that outlines the steps to design and implement a distributed continuous simulation. Implementing the system in parallel reduces the simulation time to comply with predetermined time constraints. The methodology determines the structure of the simulator, organization of the distributed tasks and management of the variable memory allocation.
A dynamic model for transient, incompressible pipe flow is used to test the parallel methodology. The generalized flow equations are developed for two applications: a tank-pipe and pipe network model. The models are translated into computer algorithms using parallel techniques developed in the simulation methodology. The individual subroutines of the simulation are directly implemented on a parallel processing and a multi-tasking computer. The flow algorithms are tested on both computers to demonstrate the benefits obtained by using the parallel methodology on a multi-processor computer. Model sizes are varied to provide a performance scale comparing multi-processor results with that of a single processor.

From the second half of the '90s, some software engineering practitioners introduced a new group of software development methodologies called Agile Methodologies (Ams): they have been developed to overcome the limits of the traditional approaches in the software development. FLOSS (Free Libre Open Source Software) has been proposed as possible different solution to the software crisis that is afflicting the ICT worldwide business. If the AMs improve the quality code and allow to respond quickly to requirement changes, FLOSS approach decreases the development costs and increases the spreading of competences about the software products. A debate is shaping about the compatibility of these two approaches. Software development teams have been spreading around the world, with users in Europe, management in the USA and programmers in the USA and India. The scattering of team members and functions around the world introduces barriers to productivity, cultural and languages differences can lead to misunderstanding of requirements, time zone differences can delay project schedules. Agile methods can provide a competitive advantage by delivering early, simplifying communication and allowing the business to respond more quickly to the market by changing the software. Trying to distribute a development project in an agile way isn't easy and will involve compromises. The goal of this thesis is to determine the application of the AMs in several contexts so to define which of these can be used effectively in non traditional software projects as the distributed development.

Reverse Osmosis (RO) is a membrane-based separation process applied in several industrial and food processing applications. In this research, performance of RO process is investigated in respect of two applications (a) wastewater treatment (b) concentration fruit juices using model-based techniques. For this purpose, a number of models (both 1 and 2-dimensional steady state and dynamic) for spiral wound RO process are developed based on Solution-Diffusion model and Irreversible Thermodynamic model. The models are validated against actual experimental data reported in the literature before being used in further simulation and optimisation studies for both wastewater treatment and fruit juice concentration. Wastewater effluents of many industrial applications contain a variety of micro-pollutants and highly-toxic compounds, which are released into a variety of water resources. Such pollutants not only disrupt the biological ecosystem, but they also pose a real threat to the water supply for human consumption and to the aquatic ecosystems. The earlier chapters of the thesis evaluate the performance of RO process in terms of removal efficiency of toxic compounds such as chlorophenol, N-nitrosamine, etc. from wastewater. The effect of several operating parameters such as feed pressure, concentration, flow rate and temperature, on the performance of RO process are evaluated. Also, suitability of a number of different RO configurations for efficient removal of toxic compounds are evaluated. For example, (a) two-stage/two-pass RO design synthesis of RO network for the removal of chlorophenol (b) multistage multi-pass RO process with and without energy recovery option for the removal of N-nitrosamine are investigated. The dynamic response of the RO process for step changes in the operating parameters is investigated for the removal of phenolic compounds. Finally, in the context of wastewater treatment, a case study with multi compounds contaminants is suggested where a multi-objective optimisation problem has achieved the optimum rejection of all the compounds and recovery rate. In respect of food processing, RO has been considered as a prominent process in fruit juice concentration due to its ability to effectively retain the flavour, sensory, aroma and nutritional characteristics and concentrate the juice. This research elucidates one example of apple juice concentration process and focuses on highlighting successful modelling and optimisation methodology. This in turn provides an efficient method of RO process for concentrating apple juice by improving the reliability and efficiency of the underlying separation and concentration process.
Ministry of High Education and Scientific Research of Iraq

Este trabalho analisa o impacto causado no desempenho de uma simulação distribuída quando técnicas de particionamento convencionais são empregadas. Essas técnicas não levam em conta informações inerentes ao estado da simulação. Pelo fato da execução de uma simulação também estar sujeita a sofrer interferências da plataforma, informações sobre a potência computacional de cada recurso utilizado e sobre o tipo de simulação, podem ser aplicadas em seu particionamento. Foram utilizadas informações estáticas, geradas através da avaliação da plataforma com benchmarks, e dinâmicas, obtidas através de índices de carga. Os resultados obtidos da utilização destas técnicas se mostram atrativos, principalmente quando o objetivo é a execução das simulações em ambientes que não disponibilizam políticas de escalonamento específicas e sim políticas convencionais. Nos estudos de casos avaliados, observaram-se ganhos satisfatórios, como a redução de até 24% do tempo de execução, um aumento de até 22% de eficiência e 79% menos rollbacks causados. Percebe-se que dependendo do tempo que se dispõe e dos objetivos pretendidos, as técnicas convencionais podem ser empregadas em simulações distribuídas. Este trabalho também contribui com o aperfeiçoamento das duas ferramentas utilizadas: WARPED e AMIGO. Uma interface de comunicação entre as duas ferramentas foi desenvolvida, ampliando assim seus campos de utilização.
This work analyses the impact caused on distributed simulation performance when conventional partitioning techniques are employed. These techniques do not take into account inherent information about the state of the simulation. Since a simulation execution is subject to platform interference, information about the type of simulations and about the computational power of resources may be applied to the partitioning process. Static performance information, generated from evaluating the platform with benchmarks has been employed, as well as dynamic load information provided by load indices. The results obtained with this approach are attractive, mainly when the objective is to execute simulations on environments which make conventional scheduling policies available, instead of specific policies. The evaluated case studies show satisfactory performance gains of up to 24% of reduction in execution time, 22% of improvement in efficiency and reduction of up to 79% in rollbacks. So, depending on the available time and the aimed objectives, it is worth using conventional techniques to assist distributed simulation partitioning. This work also contributes to the improvement of both tools used in it: Warped and AMIGO. A communication interface has been developed to integrate the tools, extending their capabilities.

Cette thèse présente une étude sur la modélisation, la formulation par le formalisme des Systèmes Hamiltoniens à ports et la discrétisation des processus de solidification dont l'interface est supposée diffuse et est modélisée par l'approche des champs de phase. Ses travaux traitent en détail de la solidification de l'eau dans le contexte de fournir des modèles numériques adaptés à la simulation, à la conception et au contrôle de procédés de purification de l'eau. Le premier chapitre rappelle d'abord de manière synthétique les modèles physiques de systèmes biphasique et de leur interface. Il présente ensuite en détail l'approche des champs de phase pour la modélisation des interfaces diffuses ainsi que le modèle thermodynamique du système biphasique. Puis il rappelle le modèle dynamique de la solidification d'une espèce, en particulier de l'eau, comme un système de deux équations d'évolution, l'équation d'Allen-Cahn et l'équation de bilan d'énergie. Ces modèles sont basés sur les propriétés thermodynamiques employant l'entropie totale comme potentiel thermodynamique. Dans le deuxième chapitre, après le rappel de la définition de systèmes hamiltoniens dissipatifs à port frontière, on rappelle que l'on peut formuler l'équation d'Allen-Cahn ainsi que le modèle de solidification complet sous cette forme, en augmentant les variables d'état avec le gradient de la variable de champ de phase. Puis l'on montre que les relations thermodynamiques issues des données sont exprimées en termes de variables intensives et mènent à une formulation hamiltonienne à port implicite. Le dernier chapitre se concentre sur la discrétisation préservant la structure du processus de solidification en utilisant la Méthode des Éléments Finis Partitionnés. Cela garantit que le modèle discrétisé conserve des propriétés clés telles que la conservation de l'énergie et la passivité. Le chapitre développe les formulations faibles, les projections et les hamiltoniens discrets pour l'équation de la chaleur et l'équation d'Allen-Cahn, puis développe la discrétisation du modèle de solidification complet. La principale contribution de ce chapitre réside dans la méthodologie de discrétisation appliquée au modèle Port Hamiltonien implicite du processus de solidification en utilisant l'entropie comme fonction génératrice. Globalement, cette thèse propose une approche pour la modélisation, la simulation et le contrôle des processus de solidification en utilisant le cadre Hamiltoniens à ports. Les résultats posent une base complète pour de futures recherches et développements dans les systèmes à paramètres distribués avec interfaces mobiles, en particulier pour les applications en ingénierie environnementale et chimique
This thesis presents a study on modeling, formulating, and discretizing solidification processes using the Port Hamiltonian framework combined with the phase field approach. The goal is to provide numerical models suitable for simulating, designing, and controlling such processes. It addresses the challenges of representing and controlling phase change phenomena in distributed parameter models with moving interfaces, with a particular focus on the solidification of pure water. The work has been motivated by the development of green processes for water purification technologies such as cyclic melt and crystallization of water, which offer a low-energy solution while minimizing the use of hazardous materials. The first chapter recalls briefly the physical models of multiphase systems and the description of the interface between the phases, in terms of thin or diffuse interfaces. It presents the phase field theory and the associated thermodynamical models of the multiphase systems. Finally, it expresses the dynamics of solidification processes as a coupled system of evolution equations consisting of the Allen-Cahn equation and energy balance equations. A main contribution of this chapter consists in a comprehensive presentation of solidification using the entropy functional approach within the phase field framework. In the second chapter, the Port Hamiltonian formulation of the dynamics of solidification processes using the phase field approach is developed. This chapter introduces Boundary Port Hamiltonian Systems and shows how an extension of the state space to the gradient of the phase field variable leads to a Port Hamiltonian formulation of the solidification model. The model is written in such a way that it utilizes the available thermodynamic data for liquid water and ice, allowing for a detailed and physically-based modeling, leading to an implicit Boundary Port Hamiltonian model. The final chapter focuses on the structure-preserving discretization of the solidification process using the Partitioned Finite Element Method. This ensures that the discretized model retains the Port Hamiltonian structure and, in turn, the key properties such as energy conservation and passivity. The chapter covers weak formulations, projections, and discrete Hamiltonians for the heat equation and the Allen-Cahn equation, leading to the spatial discretization of the solidification model. The principal contribution of this chapter lies in the discretization methodology applied to the implicit Port Hamiltonian model of the solidification process using entropy as the generating function. Overall, this thesis provides structured models of solidification processes using the Port Hamiltonian framework, providing a foundation for their physics-based simulation and control and for future research and development in distributed parameter systems with moving interfaces, particularly for environmental and chemical engineering applications

Tesis por compendio
[ES] Algunos productos se caracterizan por su falta de homogeneidad, lo que significa que productos con diferentes características pueden ser obtenidos de un mismo proceso de producción debido a factores incontrolables como la naturaleza de las materias primas o las condiciones ambientales durante la producción. Hay cuatro aspectos que caracterizan la falta de homogeneidad en el producto: los subtipos homogéneos que se obtienen de un mismo lote de producción, la cantidad de productos que componen cada subtipo, el valor de cada uno de los subtipos, y el estado de los productos. La falta de homogeneidad en el producto dificulta la gestión de los procesos de las empresas y cadenas de suministro en el momento en el que los clientes requieren homogeneidad entre las unidades de producto que adquieren. Un ejemplo de esto se produce en el sector de la cerámica, en el que los clientes requieren que todas las unidades que van a ser ensambladas juntas tengan el mismo color, espesor y calidad por razones estéticas y de seguridad. Otro ejemplo es el extraído del sector agroalimentario, en el que el mercado final requiere productos que cumplan con un tamaño mínimo, un color particular, o sabor en el caso de las frutas. Además, el sector agroalimentario tiene la complejidad añadida producida por el deterioro de los productos a lo largo del tiempo, y la necesidad de los mercados de ofrecer a los clientes productos con una mínima duración tras su venta. En esta Tesis, se define como productos heterogéneos a aquellos productos que se pueden clasificar en subtipos homogéneos con una cantidad variable, mientras que los productos perecederos son aquellos que, además de ser heterogéneos, tienen falta de homogeneidad en su estado. De acuerdo con estos conceptos, el sector cerámico comercializa productos heterogéneos mientras que el sector agroalimentario comercializa productos perecederos. Esta Tesis propone marcos conceptuales y modelos de Investigación Operativa que soporten la gestión de cadenas de suministro con productos heterogéneos y perecederos en la toma de decisiones centralizada y distribuidas relacionadas con los niveles de decisión estratégica, táctica y operativa. El objetivo es mejorar la competitividad, sostenibilidad y flexibilidad de la cadena de suministro para adaptarse a los requerimientos del mercado bajo condiciones de incertidumbre. Para esto, se han propuesto modelos de Investigación Operativa deterministas e inciertos, cuyos resultados se comparan concluyendo que los resultados obtenidos con los modelos inciertos se adaptan mejor al comportamiento real de las cadenas de suministros.Los modelos de Investigación Operativa propuestos han contribuido a tres áreas de investigación: problemas operativos en el sector cerámico, problemas estratégicos en el sector agroalimentario y problemas de planificación en el sector agroalimentario. Las principales novedades en los problemas operativos en el sector cerámico son el modelado de las características de las baldosas cerámicas, la consideración de los requerimientos de homogeneidad entre unidades de diferentes líneas de pedido, y la posibilidad de realizar entregas parciales y entregas con retraso. Esta Tesis contribuye a los problemas estratégicos en el sector agroalimentario al diseñar una cadena de suministro completa de productos agroalimentarios frescos considerando el aspecto perecedero de los productos e integrando decisiones tácticas, y determinando el impacto real que tiene considerar el aspecto perecedero de los productos durante el diseño de la cadena de suministro ...
[CA] Alguns productes es caracteritzen per la seua falta d'homogeneïtat, el que significa que productes amb diferents característiques poden ser obtinguts d'un mateix procés de producció degut a factors incontrolables com la naturalesa de les matèries primeres o les condicions ambientals durant la producció. Hi ha quatre aspectes que caracteritzen la falta d'homogeneïtat en el producte: els subtipus homogenis que s'obtenen d'un mateix lot de producció, la quantitat de productes que componen cada subtipus, el valor de cada un dels subtipus, i l'estat dels productes. La falta d'homogeneïtat en el producte dificulta la gestió dels processos de les empreses i cadenes de subministrament en el moment en què els clients requerixen homogeneïtat entre les unitats de producte que adquirixen. Un exemple d'açò es produïx en el sector de la ceràmica, en el que els clients requerixen que totes les unitats que seran acoblades juntes tinguen el mateix color, grossària i qualitat per raons estètiques i de seguretat. Un altre exemple és l'extret del sector agroalimentari, en el que el mercat final requerix productes que complisquen amb una grandària mínima, un color particular, o sabor en el cas de les fruites. A més, el sector agroalimentari té la complexitat afegida produïda pel deteriorament dels productes al llarg del temps, i la necessitat dels mercats d'oferir als clients productes amb una mínima duració després de la seua venda. En aquesta Tesi, es definix com a productes heterogenis a aquells productes que es poden classificar en subtipus homogenis amb una quantitat variable, mentres que els productes peribles són aquells que, a més de ser heterogenis, tenen falta d'homogeneïtat en el seu estat. D'acord amb aquests conceptes, el sector ceràmic comercialitza productes heterogenis mentres que el sector agroalimentari comercialitza productes peribles. Aquesta Tesi proposa marcs conceptuals i models d'Investigació Operativa que suporten la gestió de cadenes de subministrament amb productes heterogenis i peribles en la presa de decisions centralitzada i distribuïdes relacionades amb els nivells de decisió estratègica, tàctica i operativa. L'objectiu és millorar la competitivitat, sostenibilitat i flexibilitat de la cadena de subministrament per adaptar-se als requeriments del mercat sota condicions d'incertesa. Per a açò, s'han proposat models d'Investigació Operativa deterministes i incerts, els resultats es comparen concloent que els resultats obtinguts amb els models incerts s'adapten millor al comportament real de les cadenes de subministraments. Els models d'Investigació Operativa proposats han contribuït a tres àrees d'investigació: problemes operatius en el sector ceràmic, problemes estratègics en el sector agroalimentari i problemes de planificació en el sector agroalimentari. Les principals novetats en els problemes operatius en el sector ceràmic són el modelatge de les característiques de les rajoles ceràmiques, la consideració dels requeriments d'homogeneïtat entre unitats de diferents línies de comanda, i la possibilitat de realitzar lliuraments parcials i lliuraments amb retard. Aquesta Tesi contribueix als problemes estratègics en el sector agroalimentari al dissenyar una cadena de subministrament completa de productes agroalimentaris frescos considerant l'aspecte perible dels productes, integrant decisions tàctiques, i determinant l'impacte real que té considerar l'aspecte perible dels productes durant el disseny de la cadena de subministrament ...
[EN] Some products are characterised by their lack of homogeneity, what means that products with different characteristics can be obtained from the same production process due to uncontrollable factors such as the nature of raw materials or the environmental conditions during production. There are four aspects that characterize the lack of homogeneity in the product: the homogeneous subtypes to be obtained from a production lot, the quantity of products that belong to each subtype, the value related to each of the subtypes and the state of the products. The lack of homogeneity in the product hinders the management of the supply chain or company's processes at the time customers require the homogeneity among the acquired units of product. An example of this is produced in the ceramic tile sector, in which customers need all acquired ceramic tiles that are going to be jointly assembled to have the same colour, thickness and quality for aesthetic and safety reasons. Another example is the extracted from the agri-food sector, in which final markets require products that meet some characteristics such as a minimum size, a particular colour or flavour in the case of fruits. In addition, the agri-food sector has the added complexity produced by the deterioration of products over time, and the need of markets to offer to end consumers products with a minimum durability after sale. In this Thesis, heterogeneous products are defined as products for which different subtypes can be obtained in a variable quantity while perishable products are those that, apart from being heterogeneous, have a lack of homogeneity in their state. According to these concepts, ceramic sectors would commercialize heterogeneous products while the agri-food sector would do so with perishable products. This Thesis proposes conceptual frameworks and Operations Research models to support the management of supply chains with heterogeneous and perishable products in centralized and distributed decision-making processes related to strategic, tactical and operative decisional levels. The objective is to improve the supply chain competitiveness, sustainability and flexibility to adapt to market requirements under uncertain conditions. For this, both deterministic and uncertain Operations Research models have been proposed, whose results are compared concluding that results obtained with uncertain models better fit with the behaviour of real supply chains. The proposed Operations Research models have contributed to three research areas: operational problems in the ceramic sector, strategic problems in the agri-food sector and planning problems in the agri-food sector. Main novelties in the ceramic operational problems are the modelling of the characteristics of ceramic tile products, the consideration of homogeneity requirements between units from different order lines, and the possibility of making partial deliveries and delayed deliveries. This Thesis contributes to strategic problems in agri-food products by designing an entire fresh agri-food supply chain considering the perishability of products and integrating tactical decisions, and by determining the real impact that considering the products' perishability has on the supply chain design process ...
This Thesis has been developed in the Research Centre of Management and Production Engineering (CIGIP, for its acronym in Spanish “Centro de Investigación en Gestión e Ingeniería de Producción”) of the Universitat Politècnica de València with the support of the predoctoral grant Programme of Formation of University Professors (FPU, for its acronym in Spanish “Formación de Profesorado Universitario”) from the Spanish Ministry of Science, Innovation and Universities (Ref. FPU15/03595). The supervisors of this Thesis are Dr. Angel Ortiz, and Dra. María del Mar Alemany Diaz that are Professors in the Research Centre of Management and Production Engineering (CIGIP) of the Universitat Politècnica de València. The FPU grant has been endorsed by the supervisor Dr. Ángel Ortiz. This Thesis has also been supported by the project ‘RUC-APS: Enhancing and implementing Knowledge based ICT solutions within high Risk and Uncertain Conditions for Agriculture Production Systems’ (Ref. 691249) funded by the EU under its funding scheme H2020-MSCA-RISE-2015, the project ‘Methods and models for operations planning and order management in supply chains characterised by uncertainty in production due to the lack of product uniformity’ (PLANGES-FHP) (Ref. DPI2011- 23597) funded by the Spanish Ministry of Economy and Competitiveness. The projects RUC-APS and PLANGES-FHP have been led by the one of the supervisors of this Thesis Dr. María del Mar Eva Alemany. In order to obtain the international mention for this Thesis, three months of research stages have been made in the research agency Agenzia Lucana di Sviluppo e di Innovazione in Agricoltora, located in Metaponto (Italy)
Esteso Álvarez, A. (2020). Operations research models for the management of supply chains of perishable and heterogeneous products in uncertain contexts. Application to the agri-food and ceramic sectors [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/141099
TESIS
Compendio

Dans un premier temps, nous présentons des modèles permettant de décrire des systèmes de processus communicants, synchronisés par rendez-vous, ainsi que les différentes théories qui traitent le problème de la comparaison observationnelle. Nous abordons ensuite le problème à partir du langage FP2. Nous proposons une démarche qui permet de faire totalement abstraction des événements internes des processus et d'exprimer le comportement de communication des processus en n'utilisant que les événements de communication avec l'environnement. Enfin, une notion de contexte est définie et étudiée

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This work presents methodology for voltage adequacy into electric power distribution network with the insertion of photovoltaic distributed generation. Deterministic, heuristic and hybrid optimization methods are used to find the variables: i) geographical siting, ii) supply power and iii) amount of photovoltaic distributed generation. The main characteristic of the methodology is the obtaining of the amount of photovoltaic distributed generation units necessary for the adequacy of electric network voltage, respecting the supply power of each generation unit. The results indicate improvement in voltage levels after insertion of photovoltaic distributed generation units with optimized parameters for different voltage transgression scenarios. The proposed methodology is efficient for voltage adequacy through the insertion of photovoltaic distributed generation.
Este trabalho apresenta metodologia para adequação de tensão na rede de distribuição de energia elétrica com a inserção de geração distribuída fotovoltaica. São utilizados métodos de otimização determinístico, heurístico e híbrido para encontrar as variáveis: i) posição geográfica, ii) potência de fornecimento e iii) quantidade de geração distribuída fotovoltaica. A principal característica da metodologia é a obtenção da quantidade de unidades de geração distribuída fotovoltaica necessárias para a adequação de tensão da rede elétrica, respeitando a potência de fornecimento de cada unidade de geração. Os resultados indicam melhoria nos níveis de tensão após inserções de unidades de geração distribuída fotovoltaica com parâmetros otimizados para diferentes cenários de transgressão de tensão. A metodologia proposta é eficiente para adequação de tensão através da inserção de geração distribuída fotovoltaica.

The same forces that spurred the development of multicomputers - the demand for better performance and economy - are driving the evolution of multicomputers in the direction of more abundant and less expensive computing nodes - the direction of fine-grain multicomputers. This evolution in multicomputer architecture derives from advances in integrated circuit, packaging, and message-routing technologies, and carries far-reaching implications in programming and applications. This thesis pursues that trend with a balanced treatment of multicomputer programming and applications. First, a reactive-process programming system - Reactive-C - is investigated; then, a model application- discrete-event simulation - is developed; finally, a number of logic-circuit simulators written in the Reactive-C notation are evaluated.

One difficulty m multicomputer applications is the inefficiency of many distributed algorithms compared to their sequential counterparts. When better formulations are developed, they often scale poorly with increasing numbers of nodes, and their beneficial effects eventually vanish when many nodes are used. However, rules for programming are quite different when nodes are plentiful and cheap: The primary concern is to utilize all of the concurrency available in an application, rather than to utilize all of the computing cycles available in a machine. We have shown in our research that it is possible to extract the maximum concurrency of a simulation subject, even one as difficult as a logic circuit, when one simulation element is assigned to each node. Despite the initial inefficiency of a straightforward algorithm, as the the number of nodes increases, the computation time decreases linearly until there are only a few elements in each node. We conclude by suggesting a technique to further increase the available concurrency when there are many more nodes than simulation elements.

Chapter 2 sets out the basic framework. It considers an economy evolving indefinitely in discrete time, with producers, consumers, and a central bank as principal actors. Individuals plan over finite horizons and form expectations according to what they see. Money is conceived of as a commodity that is produced through credit creation rather than distributed by a fancy helicopter. This natural way to represent money is rarely followed in the literature and differs sharply from the usual helicopter drops because it ties money creation to credit creation. The chapter’s upshot is a system of simultaneous equations determining prices, wages, and the nominal interest rate. Using this solution, individuals revise their expectations, and the economy proceeds to the next period. The chapter concludes with functional and numerical specifications for later simulations, the purpose of which is to analyze key economic processes and to derive meaningful results.

The Higher Education Institutions that run business management programs in Malaysia is under severe criticism from industry that the passing out management graduates do not have adequate practical exposure to the industry and lack of practical skills to deal industrial issues proactively as the catalyst of change.This indicates that the traditional management education curriculum, as presently constituted, may not be adequately preparing individuals for the challenges they experience as professional managers.To deal with this issue, many management institutes are adopting case study as a pedagogy, a hypothetical or actual business situation to formulate a recommended policy or decision based on the facts and figures provided, to induce practical exposure to the students by simulating case situations, which improve students analytical skills and decision-making skills.A case study in business management course is a rigorous analysis of an incident, situation, person, crisis or any such phenomenon or concept, in relation to industry, business or people in the organisations.It is well related to the management, process or methodology adopted by the organisation stressing analysis of chain of events for better change management in relation to business operation context. The case studies included in this book provides better perspective of various issues and situations in the business field.The cases are written from the field of Organisational Behaviour, Human Resource Management, Marketing, Business Ethics, International Business, Strategic Management, Business Laws and General Management. These case studies are to be thoroughly analyzed by the faculty members before applying that into the classroom. It is expected that the faculty members should refer to the similar case scenarios at local and international levels to stimulate students to have better discussion on the multifaceted issues or situation. Instead of a direct entry into theoretical concepts, the author suggests that the faculty members distribute these cases well in advance and invite students to come for creative discussions and practical solutions.By preparing solutions to case studies, the students will be exposed to a variety of business operations, business process, management roles, and business situations.Thus the case studies can adequately integrate theoretical concepts effortlessly in realistic situations with better referential skills.The 50 cases included in this book can extremely be valuable in preparing students a career in industry by giving better chance to develop analytical and decision-making skills in the classroom that meet up the challenges of industry.

AbstractThe phenomenon of bank erosion and collapse is widely distributed in major rivers all over the world, and it is a kind of natural disaster with greater hazards. Bank erosion in seasonally frozen rivers (SFR) is subject to the coupling effects between hydrodynamic forces and freeze-thaw, and the mechanism is complex. Understanding of bank erosion mechanisms is of great significance for river bank protection and comprehensive river management. Taking the downstream near dam section of the Dadingzishan Navigation and Hydropower Project in the mainstream of the Songhua River as an example, the BSTEM model was used to analyze the degrees of riverbank stability in different periods considering the freeze-thaw effect. The results indicated that the degrees of riverbank stability are high during the periods of low water level and water-level rising before the flood season, and the slope toe scour is the main factor; and they are low during the periods of high water level and water-level recession with the continuous bank collapse occurring; The freezing and thawing effect has an important effect on the stability of river banks in the seasonal frozen region. so as to provide a certain reference for the study on the bank collapse of the river in seasonal freezing region and its simulation for the study of riverbank erosion in seasonally frozen rivers.

The risk of pluvial flooding is going to increase as climate change causes an increase in intense precipitation along with urbanisation leading to an increase in impermeable surfaces. In the last decade, cities such as Malmö and Copenhagen have already experienced severe pluvial flooding that has caused extensive damage. Adapting to climate change by creating flood resilient urban areas is therefore important and blue-green infrastructure (BGI) may be one measure to accomplish this. A hydrological model called TFM-DYN has been used to investigate whether BGI can aid the mitigation of pluvial flooding. TFM-DYN can also assist in selecting the best locations of BGIs. The problem of modeling urban floods using distributed high resolution hydrological models while considering the hydrological process in the upstream area is difficult due to the limited current computation capacity. However, coupling a distributed hydrological model (TFM-DYN) with an other semi distributed models (HYPE) is crucial to enable simulate, predict and map floods with high-resolution for an urban area while considering its catchment area. With the using of the new suggested coupled hydrological model, it is possible to connect and use the output results from HYPE model as an input to a distributed model (TFM-DYN). The interaction between HYPE and TFM-DYN will consider the hydrologic process occurred outside the model boundary of the interested urban area. The coupling of the two models will help initiating the model with real water depth data that may lead to more realistic simulation. The procedure of input data manipulation using the two model interactions is explained in details. The model is tested on a selected urban area to dynamically simulate the changes in the water depth with time using high resolution gridded data. The new coupled model can be of a great tool for wide range of user and stakeholders as an example to municipalities, water experts, insurance companies and to all other interested water organizations who have access to regional catchment models and in need for a high-resolution, flood simulation and mapping model.

The following manual has been prepared with the idea of facilitating the learning process in the use of the Hydro-BID model and the Analytical Hydrographic Database for Latin America and the Caribbean (LAC-AHD). The instructions below are supported by the material distributed in Hydro-BID’s installation package and that is based on the simplified case study of a River basin in the state of Pernambuco, Brazil. By following the instructions you should be able to understand how to set up a simulation in Hydro-BID, how to proceed for the interpolation of climate data, how to calibrate the model and how to visualize the results obtained. The technical information relating to the model and the LAC-AHD database can be obtained by downloading the technical notes from our website www.hydrobidlac.org.

Computer simulation of technical objects and processes is one of the components of the system of professional training of a modern electromechanics engineer. It has been established that despite the fact that mobile Internet devices (MID) are actively used by electrical engineers, the methods of using them in the process of bachelor in electromechanics training is considered only in some domestic scientific studies. The article highlights the components of the methods of using MID in the formation of the ICT component of the competence of the bachelor in electromechanics in modeling of technical objects, providing for students to acquire basic knowledge in the field of Computer Science and modern ICT and skills to use programming systems, math packages, subroutine libraries, and the like. For processing tabular data, it is proposed to use various freely distributed tools that do not significantly differ in functionality, such as Google Sheets, Microsoft Excel, for processing text data – QuickEdit Text Editor, Google Docs, Microsoft Word. For 3D-modeling and viewing the design and technological documentation, the proposed comprehensive use of Autodesk tools in the training process.

The EU Single Farm Payment (SFP) is currently distributed in proportion to primary factor shares in version 8 of the GTAP database. In this paper, we investigate whether this way of modeling the EU SFP makes a difference in analyzing agricultural policy reforms. To do so, we create alternative versions of the GTAP database to compare the effects with the default setting in GTAP. Employing OECD data, along with the GTAP framework, we vary the assumptions about the allocation of the SFP. In the process, we demonstrate how to alter and update the GTAP database to implement domestic support of OECD PSE tables. We provide a detailed overview supplemented with assumptions of payment allocation, shock calculations and in particular, the Altertax procedure to update value flows and price equations extended in the GTAP model. Subsequently, we illustrate the impact of those assumptions by simulating a 100% removal of the SFP using the deviating versions of GTAP database. This sensitivity analysis reveals strong differences in results, but particularly in production responses of food and agricultural sectors that decrease with an increasing degree of decoupling. Furthermore, our analysis shows that the effect on welfare and the trade balance decreases with an increasing degree of decoupling. This experiment shows that the allocation of the SFP can have strong impacts on simulation results.

The crisis of the system of professional development and personnel training in the energy sector exists not only in Ukraine but also all over the world. The article describes the concept of development and functioning of the industry system of personnel training in the energy sector of Ukraine. The importance of using modern web-oriented technologies to improve the skills of operational and dispatching personnel in the energy sector of Ukraine is substantiated. The meth- ods of distributed power system operating modes modelling are presented. De- velopment and software tools for the construction of distributed simulating sys- tems and particular features of cloud technologies application for the creation of a virtual training centers network in the energy sector, as well as the ways to automate the process of simulating scenarios development are described. The ex- perience of introducing remote training courses for energy specialists and remote web-based training simulators based on a comprehensive model of the energy system of Ukraine is presented. An important practical aspect of the research is the application of software and data support for the development of personnel key competencies in the energy sector for rapid recognition of accidents and, if necessary, accident management. This will allow them to acquire knowledge and practical skills to solve the problems of analysis, modelling, forecasting, and monitoring data visualization of large power systems operating modes.

Pesticide leaching in heterogeneous field soils is relatively unstudied and is the focus of this project. A wide variety of heterogeneous soils exist, characterized by processes that result from the presence of structural cracks, worm holes, and other preferred pathways within which the majority of transport can occur (called physical non-equilibrium processes), along with the presence of sorption processes that are both equilibrium and kinetic (chemical non-equilibrium processes). Previous studies of pesticide leaching have focused primarily on relatively homogeneous soils, which are less widely distributed in nature, but more studied due to the relative ease with which quantitative theory can be applied to interpret experimental results. The objectives of the proposed project were: first, to gain greater insight into the basic physical and chemical processes that characterize non-equilibrium systems, second, to improve our ability to predict pesticide leaching in heterogeneous field soils, and third, to estimate the consequences of non-equilibrium processes at the field scale by conducting an analysis of the probability of pesticide leaching when non-equilibrium processes prevail. The laboratory, theoretical and modelling aspects of the project were successful; the field aspects less so. We gained greater insight into basic processes in heterogeneous field soils, and we improved and tested tools (simulation models) and the methodology of using such tools for assessing the probability of pesticide leaching as a contribution to broader risk analysis efforts.

Snow is a critical component of the global hydrologic cycle and is a key input to river and stream flow forecasts. In 2016, the National Oceanic and Atmospheric Administration launched the National Water Model (NWM) to provide a high-fidelity numerical forecast of streamflow integrated with the broader atmospheric prediction modeling framework. The NWM is coupled to the atmospheric model using the Noah-MP land surface modeling framework. While snow in Noah-MP has been consistently evaluated in the western United States, less attention has been paid to understanding and optimizing its performance in the Northeast US (NEUS). The newly installed New York State Mesonet (NYSM), a network of high-quality surface meteorological stations distributed across New York State, provides a unique opportunity to evaluate Noah-MP performance in the NEUS. In this report, we document the methodology used to perform single-column simulations using meteorological inputs from the NYSM and compare the point evaluations against baseline NWM performance. We further discuss how enhanced surface energy balance measurements at a selection of NYSM sites can be used to evaluate specific components of Noah-MP and present initial results.

Evapotranspiration is one of the major components of Earth’s Water Balance, being the sum of evaporation and plant transpiration from the land and ocean surface. This report documents edcrop, a Python package that use climate input to simulate field-scale evapotranspiration and drainage from the root zone of an area covered with a crop, a wetland, or a forest. The conceptual model implemented in edcrop is a modification of the Evacrop model by Olesen and Heidmann (2002), which itself builds on the Watcros model by Aslyng and Hansen (1982). The edcrop conceptualization is based on considerations regarding the physical processes that are important for turning precipitation and irrigation into either evaporation, transpiration, or drainage from the root zone: Temperature determines whether precipitation falls as rain or snow, and it determines when snow thaws and infiltrates. The vegetation intercepts a part of precipitation, while the rest infiltrates into the ground. The infiltrated water will either evaporate, be absorbed by plant roots, be stored in the soil, or drain from the root zone. Potential evaporation is distributed between vegetation and soil, where the former part drives evaporation of intercepted water and plant transpiration from the green leaf area, while the latter part drives evaporation from the soil. The soil’s ability to store water depends on its field capacity; when the water content exceeds field capacity, water will gradually drain downwards. Furthermore, it is assumed that the annual life cycle of crops and wetland vegetation can be described by growing degree-days alone, while for forests the life cycle is described by a calendar. For irrigation, either (i) date and amount are input, or (ii) they are determined automatically by edcrop using certain criteria. There are two alternative soil water balance functions to choose between in edcrop. The first alternative is an almost straight copy of the function used in the original Evacrop code by Olesen and Heidmann (2002), simulating flow through the soil profile as flow through two linear reservoirs using daily time steps. However, it can simulate macro-pore drainage, which the original Evacrop cannot. The second alternative simulates flow through the soil profile as flow through four linear or nonlinear reservoirs using daily or sub-daily time steps. For nonlinear reservoirs, edcrop uses Mualem – van Genuchten like functions. It also simulates gravity driven macro-pore flow as well as precipitation loss due to surface runoff. As input, given in text files, edcrop requires daily temperature, precipitation, and reference evapotranspiration. It also requires information about combination(s) of soil type and vegetation type to simulate. One can choose between seven default soil types and fifteen default vegetation types, or one can manually input information for other types of soil or vegetation. In a single model run, edcrop can loop through lists of climate files, soils, and vegetation. Edcrop can be imported and used in own python script, or it can be executed from the command line as a script.