Academic literature on the topic 'Linear systems; Mathematical optimization; Reliability (Engineering) – Mathematical models'
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Journal articles on the topic "Linear systems; Mathematical optimization; Reliability (Engineering) – Mathematical models"
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Bogdanov, Sergey. "Application of Neural Networks in the Construction of Nonlinear Models of Field-Effect Transistors." Infocommunications and Radio Technologies 5, no. 1 (March 25, 2022): 45–53. http://dx.doi.org/10.29039/2587-9936.2022.05.1.03.
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The nonlinear model of a field-effect transistor based on the mathematical apparatus of the theory of artificial neural networks was developed. The main feature of this model is the possibility of training neural networks used to approximate the current-voltage characteristic and the gate-drain and gate-source capacitances of a nonlinear transistor model by using optimization algorithms built into popular microwave CAD systems. This makes it possible to use the well-known advantages of neural networks in the problems of function approximation to increase the reliability of the results of non-linear modeling of microwave devices based on field-effect transistors.
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Andriy Viktorovich, Goncharenko. "Hybrid-Optional Effectiveness Functions Entropy Conditional Extremization Doctrine Contributions into Engineering Systems Reliability Assessments." Transactions on Aerospace Research 2019, no. 2 (June 1, 2019): 90–100. http://dx.doi.org/10.2478/tar-2019-0012.
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Abstract In this publication a Doctrine for the Conditional Extremization of the Hybrid-Optional Effectiveness Functions Entropy is discussed as a tool for the Reliability Assessments of Engineering Systems. Traditionally, most of the problems having been dealt with in this area relate with the probabilistic problem settings. Regularly, the optimal solutions are obtained through the probability extremizations. It is shown a possibility of the optimal solutions “derivation”, with the help of a model implementing a variational principle which takes into account objectively existing parameters and components of the Markovian process. The presence of an extremum of the objective state probability is observed and determined on the basis of the proposed Doctrine with taking into account the measure of uncertainty of the hybrid-optional effectiveness functions in the view of their entropy. Such approach resembles the well known Jaynes’ Entropy Maximum Principle from theoretical statistical physics adopted in subjective analysis of active systems as the subjective entropy maximum principle postulating the subjective entropy conditional optimization. The developed herewith Doctrine implies objective characteristics of the process rather than subjective individual’s preferences or choices, as well as the states probabilities maximums are being found without solving a system of ordinary linear differential equations of the first order by Erlang corresponding to the graph of the process. Conducted numerical simulation for the proposed mathematical models is illustrated with the plotted diagrams.
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Larrahondo, Diego, Ricardo Moreno, Harold R. Chamorro, and Francisco Gonzalez-Longatt. "Comparative Performance of Multi-Period ACOPF and Multi-Period DCOPF under High Integration of Wind Power." Energies 14, no. 15 (July 27, 2021): 4540. http://dx.doi.org/10.3390/en14154540.
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Today, the power system operation represents a challenge given the security and reliability requirements. Mathematical models are used to represent and solve operational and planning issues related with electric systems. Specifically, the AC optimal power flow (ACOPF) and the DC optimal power flow (DCOPF) are tools used for operational and planning purposes. The DCOPF versions correspond to lineal versions of the ACOPF. This is due to the fact that the power flow solution is often hard to obtain with the ACOPF considering all constraints. However, the simplifications use only active power without considering reactive power, voltage values and losses on transmission lines, which are crucial factors for power system operation, potentially leading to inaccurate results. This paper develops a detailed formulation for both DCOPF and ACOPF with multiple generation sources to provide a 24-h dispatching in order to compare the differences between the solutions with different scenarios under high penetration of wind power. The results indicate the DCOPF inaccuracies with respect to the complete solution provided by the ACOPF.
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Al-Subhi, Ahmad. "Dynamic Economic Load Dispatch Using Linear Programming and Mathematical-Based Models." Mathematical Modelling of Engineering Problems 9, no. 3 (June 30, 2022): 606–14. http://dx.doi.org/10.18280/mmep.090307.
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Economic dispatch (ED) is one of the most important topics in power system operation and planning. The main purpose of this paper is to develop simple and effective mathematical models for the ED problem. Two stages were considered to solve this problem. First, the ED problem is formulated using linear piecewise functions and then optimally solved using the LP technique at various load values. The effectiveness of the LP in optimally solving the ED problem is verified by applying it to two different test systems. The results are compared with those obtained using other ED optimization techniques. The LP optimization performance of the proposed method is found to be similar to those of the reported techniques. In the second stage, the data collected from the optimization process in the first stage are transferred to TuringBot software. This software is adopted to build efficient mathematical models for the optimal power generation (output parameters) as functions of the load values (input parameters). The main objective of these models is to easily evaluate the optimal power sharing of the generators in an online fashion under rapid variable loading conditions without the need to solve the ED-LP based problem. Optimization techniques, including the LP, generally require considerable simulation times for linearization and optimization code execution, particularly under fast load variations. Thus, the main features of the developed models in this paper are simplicity, accessibility, as well as the ability in obtaining an efficient and optimal solution with a faster execution time.
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Stetsyuk, Petro, Oleksii Lykhovyd, Volodymyr Zhydkov, and Anton Suprun. "OPTIMIZATION PROBLEMS OF MODERNIZATION OF THE CAPACITY OF ARCS OF FAULT-TOLERANT NETWORKS." Journal of Automation and Information sciences 5 (September 1, 2021): 5–20. http://dx.doi.org/10.34229/1028-0979-2021-5-1.
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Mathematical models of two classes of problems of modernization of the capacity of arcs of fault-tolerant oriented networks are considered. A network is considered to be fault-tolerant for which it is possible to satisfy all the demands for the transmission of flows when there will be one, but any failure, from all possible single network failures. For the first class of problems (problem A), all possible paths in the network can be used for the transmission of flows. For the second class of problems (problem P), only paths from a predetermined set of paths are used to transfer flows. Mathematical models are represented by linear, Boolean and nonlinear programming problems with a block structure of the constraint matrix.The material of the article is presented in five sections. The first section describes the concepts of a single failure and the scenario of network failures, the content of optimization problems A and P for modernization of capacity of arcs of a fault-tolerant network, a test network (6 vertices and 19 arcs) to test algorithms for solving the problems of modernization of fault-tolerant networks. In the second section, basic models of linear programming problems for finding the capacities of arcs of the fault-tolerant physical structure of a network (problem A) and the fault-tolerant logical structure of a network (problem P) are described, and their properties are considered. The third section describes problems A and P in the form of mixed Boolean linear programming models. Optimal solutions of problem A for various failure scenarios are given for the example of the test network. The solutions were found using the Gurobi program from the NEOS server, where the mathematical model of problem A is described in the AMPL modeling language.The fourth section describes nonlinear convex programming models for problems A and P, developed to find the optimal capacities of fault-tolerant networks according to the selected criterion, and a decomposition algorithm for their solution. The fifth section describes software in the FORTRAN programming language for the decomposition algorithm based on efficient implementations of Shor’s r-algorithms. The decomposition algorithm is compared with the IPOPT program based on the results of solving test problems.
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Velmisov, Petr A., and Andrey V. Ankilov. "Mathematical modeling in problems about dynamics and stability of elastic elements of wing profiles." Cybernetics and Physics, Volume 10, 2021, Number 3 (November 30, 2021): 201–12. http://dx.doi.org/10.35470/2226-4116-2021-10-3-201-212.
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The mathematical models describing the dynamics of elastic elements of wing structures and representing the initial-boundary value problems for systems of partial differential equations are proposed. The dynamics and stability of elastic elements of wings, flown around by a gas or liquid stream in a model of an incompressible medium, are investigated. To study the dynamics of elastic elements and a gas-liquid medium, both linear and nonlinear models of the mechanics of a solid deformable body and linear models of the mechanics of liquid and gas are used. On the basis of the constructed functionals for partial differential equations, the sufficient stability conditions are obtained in analytical form. The conditions impose restrictions on the parameters of mechanical systems. The obtained stability conditions are necessary for solving the problems of controlling the parameters of the aeroelastic system. On the basis of the Galerkin method, a numerical study of the dynamics of elastic elements was carried out, the reliability of which is confirmed by the obtained analytical results.
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Cevikcan, Emre. "A mathematical programming approach for walking-worker assembly systems." Assembly Automation 34, no. 1 (January 28, 2014): 56–68. http://dx.doi.org/10.1108/aa-07-2013-067.
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Purpose – It has become increasingly critical to design and maintain flexible and rapid assembly systems due to unpredictable and varying market conditions. The first stage of developing such systems is to restructure the existing assembly system. After designing the manufacturing system, efforts should be made for capacity adjustments to meet the demand in terms of allocating tasks to workers. Walking-worker assembly systems can be regarded as an effective method to achieve flexibility and agility via rabbit chase (RC) approach in which workers follow each other around the assembly cell or line and perform each task in sequence. In this paper, a novel mathematical programming approach is developed with the aim of integrating RC in assembly processes. Therefore, this study is thought to add value to industrial assembly systems in terms of effectively raising engineering control for task allocation activities. Design/methodology/approach – Two consecutive mathematical models are developed, since such a hierarchical approach provides computational convenience for the problem. The initial mathematical programming model determines the number of workers in each RC loop for each segment. In addition, the number of stations and the distribution of station times in the segments is essential. Therefore, the succeeding mathematical programming model generates stations in each segment and provides convenience for the workflow in RC loops. The output of mathematical programming models are the parameters of simulation model for performance assessment. Findings – The effectiveness of the proposed approach was validated by an application in a real-life chair production system. The application resulted in performance improvements for labour requirement (12.5 per cent) and production lead time (9.6 per cent) when compared to a classical assembly system design (CASD) where one stationary worker exists in each station. In addition, it is worth to note that RC leads to a reduced number of workers for a considerable number (39.4 per cent) of test problems. What is more, input as well as output factors have been determined via discriminant analysis and their impacts to the utilization of RC were analyzed for different levels. Practical implications – This study is thought to add value to the industry in terms of effectively providing convenience during production planning and task allocation in assembly lines and cells. Originality/value – To the best knowledge of the author, optimization models for RC considering a real industrial application have not yet been developed. In this context, this paper presents an approach which models RC by the use of mathematical programming in manual assembly processes to address this research gap. The contribution of the paper to the relevant literature is the development of hierarchical mixed integer linear programming models to solve RC problem for the first time.
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Eliwa, M. S., Medhat EL-Damcese, A. H. El-Bassiouny, Abhishek Tyag, and M. El-Morshedy. "The Weibull Distribution: Reliability Characterization Based on Linear and Circular Consecutive Systems." Statistics, Optimization & Information Computing 9, no. 4 (September 24, 2021): 974–83. http://dx.doi.org/10.19139/soic-2310-5070-1132.
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Linear and circular consecutive models play a vital role to study the mechanical systems emerging in various fields including survival analysis, reliability theory, biological disciplines, and other lifetime sciences. As a result, analysis of reliability properties of consecutive k − out − of − n : F systems has gained a lot of attention in recent years from a theoretical and practical point of view. In the present article, we have studied some important stochastic and aging properties of residual lifetime of consecutive k − out − of − n : F systems under the condition n − k + 1, k ≤ n and all components of the system are working at time t. The mean residual lifetime (MRL) and its hazard rate function are proposed for the linear consecutive k − out − of − n : F (lin/con/k/n:F) and circular consecutive k − out − of − n : F (cir/con/k/n:F) systems. Furthermore, several mathematical properties of the proposed MRL are examined. Finally, the Weibull distribution with two parameters is used as an example to explain the theoretical results.
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Lixandru, Bianca Andreea, and Vlad Monescu. "LAPACK library for mathematical modeling used in 3D object reconstruction." SERIES III - MATEMATICS, INFORMATICS, PHYSICS 13(62), no. 2 (January 20, 2021): 715–22. http://dx.doi.org/10.31926/but.mif.2020.13.62.2.27.
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Over time, multiple solutions have been sought for building 3D models in the fastest and most accurate way possible. For this reason, this article proposes the use of LAPACK library for a quick solution of linear systems generated by least square method calculation. A mathematical and physical component used in the reconstruction of models consists in the use of Spherical Harmonics which represent some special functions often used in solving partial differential equations in different scientific areas. This problem finds its place in multiple domains such as medicine, engineering, programming. The target of the work described by this paper is to achieve optimization in the reconstruction of 3D models. We aim to perform real-time model reconstruction for large data sets by using Spherical Harmonics functions.
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Colina, Eliezer, Mario Peña, Villie Morocho, and Lorena Siguenza-Guzman. "Mathematical modeling to standardize times in assembly processes: Application to four case studies." Journal of Industrial Engineering and Management 14, no. 2 (March 5, 2021): 294. http://dx.doi.org/10.3926/jiem.3192.
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Purpose: This paper proposes model-based standard times estimates, using multiple linear regression, nonlinear optimization, and fuzzy systems in four real cases assembly lines. The work includes a description of the models and a comparison of their performance with values obtained using the conventional chronometer method. These models allow estimating standard times without reconducting field studies.Design/methodology/approach: For the development of the time study, the methodology applied by the International Labour Organization (ILO) was used as a baseline. This methodology is structured in three phases: selection of the case study, registration of the process by direct observation, and calculation/estimation of the standard time. The selected case studies belong to real assembly lines of motorcycles, television sets, printed circuit boards, and bicycles.Findings: In the motorcycle’s assembly case, the study allowed constructing seven linear regression models to estimate standard times for assembling the front parts, and seven linear regression models to predict standard times for the rear parts of the different motorcycle types. Compared to the classical chronometer method, the results obtained never exceeded 10%. Regarding the case studies of assembling TV sets and PCBs, the study considered the construction of nonlinear optimization models that allow making appropriate predictions of the standard times in their assembly lines. Finally, for the bicycle assembly line, a fuzzy logic model to represent the standard time was constructed and validated.Research limitations/implications: For reasons of confidentiality of information, this work omitted the names of companies, services, and models of manufactured products.Originality/value: The literature consulted does not refer to the representation of standard time on assembly lines using mathematical models. The construction of these models with empirical data from actual assembly lines was a valuable aid to the companies involved in supporting activity planning.
Dissertations / Theses on the topic "Linear systems; Mathematical optimization; Reliability (Engineering) – Mathematical models"
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O'Reilly, Małgorzata Marzena. "Necessary conditions for the variant optimal design of linear consecutive systems." Title page, contents and summary only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09pho668.pdf.
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"October 2001." Bibliography: leaves 99-103. Establishes several sets of conditioning relating to the variant optimal deign of linear consecutive-k-out-of-n systems and includes a review of existing research in the theory of variant optimal design of linear consecutive-k-out-of-n systems.
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Santos, Bruno Samways dos. "Programação de ônibus interurbano utilizando a técnica de programação linear inteira." Universidade Tecnológica Federal do Paraná, 2014. http://repositorio.utfpr.edu.br/jspui/handle/1/929.
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PAEO transporte rodoviário é um dos modais mais utilizados para o transporte de passageiros principalmente devido à sua acessibilidade, tanto no contexto nacional como mundial. As organizações buscam métodos e sistemas cada vez mais eficientes para atender de forma satisfatória seus clientes, oferencendo serviços de qualidade e confiáveis. O presente trabalho teve como objetivo propor um modelo matemático de veículos para a minimização de ônibus, evitando ao máximo o desbalanceamento da rede de transporte. O modelo buscou abranger as restrições inerentes aos fluxos em rodoviárias de modo a cobrir todas as viagens de uma tabela de horários já definida, alocando apenas um veículo para cada viagem e aproveitando o mesmo para outras viagens quando possível, atendendo à função objetivo. O modelo foi aplicado à uma empresa de transportes de passageiros com quatro cidades envolvidas e 105 viagens em um tempo de 24 horas. As variáveis e restrições foram identificadas a partir de entrevistas semi -estruturadas e visitas à organização, observando roteiros de viagens a serem cumpridos por dois modelos de ônibus: metropolitanos e articulados. Neste contexto, dois modelos distintos foram montados de forma a atender as viagens, sendo analisadas separadamente. Os resultados definiram um total necessário de 12 ônibus metropolitanos e 4 ônibus articulados para atender às exigências da empresa e da tabela viagens, sendo que todas as restrições foram satisfeitas, detectando -se a necessidade da realização de seis viagens mortas (sem passageiros) para suprir a necessidade de d emanda de ônibus para cada tabela de viagens diárias. Com os resultados, fez-se uma comparação com a programação que a empresa necessitava para cumprir a tabela de viagens, identificando a diminuição de um ônibus metropolitano, sem deixar de cumprir a restrição de autonomia de cada ônibus poder rodar 400 quilômetros sem necessidade de reabastecimento. Algumas melhorias foram identificadasanalisando-se a rede resultante, sendo discutidas ao final da pesquisa e norteando novas intenções de trabalhos futuros.
Road transport is one of the most used modes for passenger transport mainly due to its affordability, in the national and global context. Organizations seek for a better methods and systems to meet the satisfaction of its customers, offering quality and reliable services. This research aimed to propose a vehicle scheduling model to minimize buses, avoiding the transmission system imbalance. The model tried to cover the restrictions inherent about the vehicle flow on bus stations to cover all travel in a given timetable, allocating only one vehicle for each trip and using it for other trips when it is possible, given the objective function. The model was applied to a passenger transportation company with four cities involved and 105 trips in a time of 24 hours. The variables and constraints were identified from semi-structured interviews and visits at organization, identifying the tours to be met by two bus models: articulated and metropolitan. In this context, two different models were fitted to meet the travel , and analyzed separately. The results defined a required total of twelve metropolitan buses and four articulated buses to meet the company and timetable requirements and all constraints were satisfied, detecting the need of perform six deadheading trips (without passengers) to meet the need for demand bus for each table in the daily trips. With the results, a comparison was made between the old programming system adopted by the organization to fulfill the timetable, identifying the reduction of a metropolitan bus, while fulfilling the constraint of autonomy that each bus can travel 400 kilometers. Some improvements were identified by observing the resulting route network, being discussed at the end of the research and guiding for a new works in the future.
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Akrouche, Joanna. "Optimization of the availability of multi-states systems under uncertainty." Thesis, Compiègne, 2020. http://www.theses.fr/2020COMP2545.
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La sûreté de fonctionnement (SdF) est devenue une nécessité dans le monde industriel au cours du XXe siècle. La SdF est un domaine d’activité qui propose des moyens d’augmenter les attributs du système dans un délai raisonnable et à moindre coût. Dans l’ingénierie des systèmes, la SdF est définie comme la propriété qui permet aux utilisateurs du système de placer une confiance justifiée dans le service qu’il leur fournit et c’est une mesure de la disponibilité, de la fiabilité et de la maintenabilité d’un système, et de la performance du support de maintenance, et, dans certains cas, d’autres caractéristiques telles que la durabilité, la sûreté et la sécurité. Le concept sur lequel notre travail est basé est la textbf disponibilité. La disponibilité A(t) est la capacité d’un système à être opérationnel à un moment précis. Le coût d’un système à haute disponibilité est très cher. Le concepteur doit faire un compromis entre la disponibilité et les coûts économiques. Les utilisateurs peuvent rejeter des systèmes dangereux, peu fiables ou non sécurisés. Par conséquent, tout utilisateur (ou industrie) posera cette question avant avoir un produit : "Quel est le produit optimal sur le marché ?" Pour répondre à cette question, nous devons combiner les deux points suivants : - La meilleure disponibilité du système : l’utilisateur souhaite un produit qui dure longtemps le plus possible. - Le meilleur coût du système : l’utilisateur veut un produit sans lui coûter une fortune. Le calcul de la disponibilité est basé principalement sur la connaissance des taux de défaillance et des réparations des composants du système. L’analyse de disponibilité permet de calculer la capacité d’un système à fournir un niveau de performance requis en fonction du niveau de dégradation. Plusieurs méthodes ont été utilisées pour calculer la disponibilité d’un système, parmi lesquelles on trouve la Fonction de Génératrice Universelle (UGF), la technique d’inclusion-exclusion, les modèles de Markov, etc. Ces méthodes utilisent différentes techniques probabilistes pour évaluer ce critère, mais ces approches proposées ne restent efficaces que pour des cas très spécifiques, par exemple les cas de systèmes binaires. Un système binaire est un système où deux cas sont possibles : fonctionnement parfait et défaillance totale. Alors que les systèmes multi-états (SME) restreint considérablement l’application de la plupart de ces méthodes. Dans la vie réelle, les systèmes correspondent à des SME. Dans de tels scénarios, les systèmes et leurs composants peuvent fonctionner à différents niveaux de performances entre l’état de fonctionnement parfait et l’état de défaillance totale. Cependant, l’évaluation de la disponibilité des SME est plus difficile que dans le cas binaire, car il faut tenir compte des différentes combinaisons des modes de défaillance des composants. Tout au long de cette thèse, nous recherchons une méthode qui nous aide à calculer et à optimiser la disponibilité de SME tenant compte le facteur coûtDependability has become a necessity in the industrial world during the twentieth century. Dependability is an activity domain that proposes means to increase the attributes of the system in a reasonable time and with a less cost. In systems engineering, dependability is defined as the property that enables system users to place a justified confidence in the service it delivers to them and it is a measure of a system’s availability, reliability, and its maintainability, and maintenance support performance, and, in some cases, other characteristics such as durability, safety and security. The key concept that our work is based on is the availability. The availability A(t) is the ability of a system to be operational at a specific moment. The cost of some system with high availability is very expensive. The designer must compromise between the availability and the economic costs. Users can reject systems that are unsafe, unreliable or insecure. Therefore, any user (or industry) will ask this questionbefore getting any product: "What is the optimal product in the market?" To answer to this question, we must combine the following two points : - The best availability of the system : the user wants a product that lasts as long as possible. - The best cost of the system : the user wants a product without costing him a fortune. Availability calculation is based primarily on knowledge of failure rates and repairs of system components. Availability analysis helps to calculate the ability of a system to provide a required level of performance depending on the level of degradation. Several methods have been used to calculate the availability of a system, amongst which we find the Universal Generating Function (UGF), Inclusion-Exclusion technique, Markov models, etc. These methods employ different probabilistic techniques to evaluate this criterion, but these proposed approaches remain effective only for very specific cases, for example the cases of binary systems. A binary system is a system where only two cases are possible : perfect functioning and total failure. While the transition to multi-state systems (MSS) drastically restricts the application of most of these methods. In real life, the systems corresponds to MSS. In such scenarios, systems and their components can operate at different performance levels between working and failure states. However, the evaluation of the availability of the MSSs is more difficult than in the binary case, because we have to take into account the different combinations of the component failure modes. Throughout this thesis, we search for a method that helps us to compute and to optimize the availability of MSS
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Bettoni, Luiz Marcelo Michelotti. "Modelos plim para otimização de circuitos da rede de distribuição secundária de energia elétrica." Universidade Tecnológica Federal do Paraná, 2011. http://repositorio.utfpr.edu.br/jspui/handle/1/373.
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ANEELEm sistemas de distribuição de energia elétrica é comum o desenvolvimento de projetos que busquem a melhoria dos índices de equilíbrio de cargas, carregamento de transformadores e quedas de tensão ao longo dos circuitos da rede secundária. O presente trabalho apresenta modelos matemáticos de Programação Linear Inteira Mista (PLIM) para quatro das intervenções técnicas usualmente praticadas com vistas a estas melhorias: balanceamento de carga, troca de condutor, divisão de circuito e remanejamento de carga. Os modelos respeitam aspectos técnicos, elétricos e considerações operacionais dos especialistas na busca de soluções que minimizem o investimento necessário para restabelecimento destes índices. Um método linear simplificado para o cálculo elétrico, baseado no Backward-Forward Sweep (BFS), é proposto a fim de incluir restrições sobre níveis de tensão diretamente nos modelos. A realização conjunta das intervenções é sugerida em uma proposta de integração de modelos por encadeamento de soluções. Para desenvolvimento dos modelos PLIM criou-se o ambiente de modelagem Gusek, interface para o solver livre GLPK. Os modelos foram implementados em uma ferramenta de apoio à tomada de decisão para projetos de melhoria de rede. Resultados são apresentados através de estudos de caso com dados de circuitos reais.
In eletric power distribution systems it is common to develop projects to improve the levels of load balancing, transformer loading and voltage drops along secondary network circuits. This paper presents Mixed Integer Linear Programming (MILP) mathematical models for adressing four technical interventions usually undertaken to achieve these improvements: load balancing, conductor changing, circuit split, and load relocation. These models comply with technical and electrical aspects and satisfy operational considerations from specialists in finding solutions that minimize the required investment for restoration of circuit levels. A simplified linear power flow method, based on the Backward-Forward Sweep (BFS), is proposed to include voltage levels constraints into the models. The combination of interventions is suggested in a proposal for integration of models by chaining solutions. To develop the MILP models the GUSEK modeling environment was created as an interface for the GLPK free solver. The models were implemented in a decision-making support tool for network improvement projects. Results are presented through case studies with data from real circuits.
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O'Reilly, Małgorzata Marzena. "Necessary conditions for the variant optimal design of linear consecutive systems." Thesis, 2001. http://hdl.handle.net/2440/114935.
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Establishes several sets of conditioning relating to the variant optimal deign of linear consecutive-k-out-of-n systems and includes a review of existing research in the theory of variant optimal design of linear consecutive-k-out-of-n systems.Thesis (Ph.D.) -- University of Adelaide, Dept. of Applied Mathematics, 2001.
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Sidhu, Amardeep Singh. "Fault diagnosis of lithium ion battery using multiple model adaptive estimation." Thesis, 2013. http://hdl.handle.net/1805/4447.
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Indiana University-Purdue University Indianapolis (IUPUI)Lithium ion (Li-ion) batteries have become integral parts of our lives; they are widely used in applications like handheld consumer products, automotive systems, and power tools among others. To extract maximum output from a Li-ion battery under optimal conditions it is imperative to have access to the state of the battery under every operating condition. Faults occurring in the battery when left unchecked can lead to irreversible, and under extreme conditions, catastrophic damage. In this thesis, an adaptive fault diagnosis technique is developed for Li-ion batteries. For the purpose of fault diagnosis the battery is modeled by using lumped electrical elements under the equivalent circuit paradigm. The model takes into account much of the electro-chemical phenomenon while keeping the computational effort at the minimum. The diagnosis process consists of multiple models representing the various conditions of the battery. A bank of observers is used to estimate the output of each model; the estimated output is compared with the measurement for generating residual signals. These residuals are then used in the multiple model adaptive estimation (MMAE) technique for generating probabilities and for detecting the signature faults. The effectiveness of the fault detection and identification process is also dependent on the model uncertainties caused by the battery modeling process. The diagnosis performance is compared for both the linear and nonlinear battery models. The non-linear battery model better captures the actual system dynamics and results in considerable improvement and hence robust battery fault diagnosis in real time. Furthermore, it is shown that the non-linear battery model enables precise battery condition monitoring in different degrees of over-discharge.
Books on the topic "Linear systems; Mathematical optimization; Reliability (Engineering) – Mathematical models"
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IFIP WG 7.5 Working Conference (1st 1987 Alborg, Denmark). Reliability and optimization of structural systems: Proceedings of the First IFIP WG 7.5 Working Conference, Aalborg, Denmark, May 6-8, 1987. Edited by Thoft-Christensen Palle 1936- and IFIP WG 7. 5. Berlin: Springer-Verlag, 1987.
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Ferreres, Gilles. A practical approach to robustness analysis with aeronautical applications. New York: Kluwer Academic, 1999.
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Willems, Jan C. From Data to Model. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989.
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Stochastic reliability modeling, optimization and applications. Singapore: World Scientific Pub. Co, 2010.
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Reliability and Optimization of Structural Systems: Proceedings of the First Ifip Wg 7.5 Working Conference (Lecture Notes in Engineering). Springer, 1987.
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A Practical Approach to Robustness Analysis with Aeronautical Applications. Springer, 1999.
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Ferreres, Gilles. A Practical Approach to Robustness Analysis with Aeronautical Applications. Springer, 2013.
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Ferreres, Gilles. Practical Approach to Robustness Analysis with Aeronautical Applications. Springer London, Limited, 2007.
Find full textBook chapters on the topic "Linear systems; Mathematical optimization; Reliability (Engineering) – Mathematical models"
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Falcone, Domenico, Alessandro Silvestri, Gianpaolo Di Bona, and Antonio Forcina. "Mathematical Models for Reliability Allocation and Optimization for Complex Systems." In Human Factors and Reliability Engineering for Safety and Security in Critical Infrastructures, 43–76. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-62319-1_3.
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Bal, Alperen, and Sule Itir Satoglu. "Mathematical Optimization Models for the Maintenance Policies in Production Systems." In Handbook of Research on Applied Optimization Methodologies in Manufacturing Systems, 252–68. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-2944-6.ch012.
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This chapter initially presents a brief information about production systems. At these systems, different types of maintenance policies are developed to cope with wear out failures. Mainly used maintenance policies can be classified as corrective, preventive, and condition-based maintenance. In the corrective maintenance, repair or replacement is applied whenever components of the machine breakdown. In the preventive maintenance approach maintenance activities are applied to the critical components on a periodic basis. On the other hand, maintenance activities are applied whenever critical reliability level is reached or exceeded. These types of maintenance policies are modeled using mathematical modeling techniques such as linear programming, goal programming, dynamic programming, and simulation. A review of current literature about the mathematical models, the simulation-based optimization studies examining these maintenance policies are categorized and explained. Besides, the solution methodologies are discussed. Finally, the opportunities for future research are presented.
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Stennikov, Valery A., and Ivan V. Postnikov. "Problems of Modeling and Optimization of Heat Supply Systems." In Sustaining Power Resources through Energy Optimization and Engineering, 102–26. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-4666-9755-3.ch005.
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This chapter deals with the problem of comprehensive analysis of heat supply reliability for consumers. It implies a quantitative assessment of the impact of all stages of heat energy production and distribution on heat supply reliability for each consumer of the heat supply system. A short review of existing methods for the analysis of fuel and heat supply reliability is presented that substantiates the key approaches to solving the problem of comprehensive analysis of heat supply reliability. A methodological approach is suggested, in which mathematical models and methods for nodal evaluation of heat supply reliability for consumers are developed and the studies on the impact of different elements of fuel and heat supply systems on its level are described. Mathematical modeling is based on the Markov random processes, models of flow distribution in a heat network, deterministic dependences of thermal processes of heat energy consumption and some other models.
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Floudas, Christodoulos A. "Mixed-Integer Linear Optimization." In Nonlinear and Mixed-Integer Optimization. Oxford University Press, 1995. http://dx.doi.org/10.1093/oso/9780195100563.003.0010.
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This chapter provides an introduction to the basic notions in Mixed-Integer Linear Optimization. Sections 5.1 and 5.2 present the motivation, formulation, and outline of methods. Section 5.3 discusses the key ideas in a branch and bound framework for mixed-integer linear programming problems. A large number of optimization models have continuous and integer variables which appear linearly, and hence separably, in the objective function and constraints. These mathematical models are denoted as Mixed-Integer Linear Programming MILP problems. In many applications of MILP models the integer variables are 0 — 1 variables (i.e., binary variables), and in this chapter we will focus on this sub-class of MILP problems. A wide range of applications can be modeled as mixed-integer linear programming MILP problems. These applications have attracted a lot of attention in the field of Operations Research and include facility location and allocation problems, scheduling problems, and fixed-charge network problems. The excellent books of Nemhauser and Wolsey (1988), and Parker and Rardin (1988) provide not only an exposition to such applications but also very thorough presentation of the theory of discrete optimization. Applications of MILP models in Chemical Engineering have also received significant attention particularly in the areas of Process Synthesis, Design, and Control. These applications include (i) the minimum number of matches in heat exchanger synthesis (Papoulias and Grossmann, 1983; see also chapter 8) (ii) heat integration of sharp distillation sequences (Andrecovich and Westerberg, 1985); (iii) multicomponent multiproduct distillation column synthesis (Floudas and Anastasiadis, 1988); (iv) multiperiod heat exchanger network, and distillation system synthesis (Floudas and Grossmann, 1986; Paules and Floudas, 1988); flexibility analysis of chemical processes (Grossmann and Floudas, 1987); (v) structural properties of control systems (Georgiou and Floudas, 1989, 1990); (vi) scheduling of batch processes (e.g., Rich and Prokapakis, 1986, 1986; Kondili et al., 1993; Shah et al, 1993; Voudouris and Grossmann, 1992, 1993); and (vii) planning and scheduling of batch processes (Shah and Pantelides, 1991, Sahinidis et al, 1989, Sahinidis and Grossmann, 1991). In addition to the above applications, MILP models are employed as subproblems in the mixed-integer nonlinear optimization approaches which we will discuss in the next chapter. In this section, we will present the formulation of Mixed-Integer Linear Programming MILP problems, discuss the complexity issues, and provide a brief overview of the solution methodologies proposed for MILP models.
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Verma, Vibha, Neha Neha, and Anu G. Aggarwal. "Software Release Planning Using Grey Wolf Optimizer." In Advances in Systems Analysis, Software Engineering, and High Performance Computing, 1–44. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1718-5.ch001.
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This chapter presents the application of grey wolf optimizer in software release planning considering warranty based on the proposed mathematical model that measures reliability growth of software systems. Hence, optimal release and warranty time is determined while minimizing the overall software development cost. The software cost model is based on failure phenomenon modelled by incorporating fault removal efficiency, fault reduction factor, and error generation. The model has been validated on the fault dataset of ERP systems. Sensitivity analysis has been carried out to study the discrete changes in the cost parameter due to changes in optimal solution. The work significantly contributes to the literature by fulfilling gaps of reliability growth models, release problems considering warranty, and efficient ways for solving optimization problems. Further, the grey wolf optimizer result has been compared with genetic algorithm and particle swarm optimization techniques.
Conference papers on the topic "Linear systems; Mathematical optimization; Reliability (Engineering) – Mathematical models"
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Fernandez, Charles, Shashi Bhushan Kumar, Wai Lok Woo, Rosemary Norman, and Arun Kr. Dev. "Real-Time Prediction of Reliability of Dynamic Positioning Sub-Systems for Computation of Dynamic Positioning Reliability Index (DP-RI) Using Long Short Term Memory (LSTM)." In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18844.
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Abstract In this study, a framework using Long Short Term Memory (LSTM) for prediction of reliability of Dynamic Positioning (DP) sub-systems for computation of Dynamic Positioning Reliability Index (DP-RI) has been proposed. The DP System is complex with significant levels of integration between many sub-systems such as the Reference System, DP Control System, Thruster / Propulsion System, Power System, Electrical System and the Environment System to perform diverse control functions. The proposed framework includes a mathematical computation approach to compute reliability of DP sub-systems and a data driven approach to predict the reliability at a sub-system level for evaluation of model performance and accuracy. The framework results demonstrate excellent performance under a wide range of data availability and guaranteed lower computational burden for real-time non-linear optimization. There are three main components of the proposed architecture for the mathematical formulation of the DP sub-systems based on individual sensor arrangements within the sub-system, computation of reliability of sub-systems and optimized LSTM deep learning algorithm for prediction of its reliability. Firstly, the mathematical formulation for the reliability of sub-systems is determined based on the series/parallel arrangement of the sensors of each individual equipment item within the sub-systems. Secondly, the computation of the reliability of sub-systems is achieved through an integrated approach during complex operation of the vessel. Thirdly, the novel optimized LSTM network is constructed to predict the reliability of the subsystems while minimizing integral errors in the algorithm. In this paper, numerical simulations are set-up using a state-of-the-art advisory decision-making tool with mock-up and real-world data to give insights into the model performance and validate it against the existing risk assessment methodologies. Furthermore, we have analyzed the efficiency and stability of the proposed model against various levels of data availability. In conclusion the prediction accuracy of the proposed model is scalable and higher when compared with other model results.
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Marani, Pietro, and Cristian Ferrari. "Suppression of High Frequency Oscillations on Suspension System of Snow Groomer With Evolutionary Algorithms Optimization." In 9th FPNI Ph.D. Symposium on Fluid Power. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fpni2016-1534.
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In current engineering practice for the design and dimensioning of hydropneumatic suspension systems, the effect of main parameters is considered; this approach can be used to implement approximate models basically suitable to describe low frequency and high amplitude oscillations of the machine. The target of this study is a Snow Groomer, a tracked vehicle driven by diesel engines and equipped in front with a shovel and behind with a cutter. When the machine drives over a snowfield, it pushes snow ahead of it and, at the same time, smooths out any surface unevenness. The suspension system is the key element to ensure the driver’s safety and comfort, the effectiveness of snow grooming and finally enhance the reliability of the machine components. The on-field testing had shown high frequency pressure oscillations transmitted from the sprocket to hydraulic system, propagated through the flexible hoses. Those Pressure Oscillations cause noise and can affect negatively the durability and reliability of the Machine. A lumped parameter non-linear dynamic model of the hydraulic circuit and of the machine interactions is built in Amesim environment, including Lax Wendroff wave propagation models, to make it able to catch the high frequency oscillations experienced in the test field. Most of the design parameters are fixed (such as vehicle weight and hydraulic lines length), other parameters can be varied to study the optimal solution, these parameters define the “factors” of the optimization problem. As a next step it is important to define the objectives of the optimization, in this case corresponding to various figures of merit describing the behavior of the system in different work conditions. The large number of factors included in the lumped parameter model generates an exponentially larger number of possible configurations. Moreover the relationship between factors and objective is not always possible to express with explicit mathematical models. Finally the presence of multiple and sometimes conflicting objectives forces more refined analysis methods to be adopted. For the above mentioned reasons a Multi-objective Optimization method is proposed taking advantage of Evolutionary Algorithms and Pareto Front optimization. Two different architectural solutions are analyzed and optimized using two different algorithms, Non Sorting Genetic Algorithm II (NSGAII) and Multiple Object Swarm Particle Optimization Algorithm (MOPSO). The results of the optimization belonging to the Pareto Front will be analyzed to assess the expected improvement of the suspension performance and will be chosen as candidates for a new setting of the Snow Groomer. Furthermore a comparison in terms of effectiveness and speed in finding solutions will be given for the current simulation environment.
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Cavalca, Katia Lucchesi, Sérgio Junichi Idehara, Franco Giuseppe Dedini, and Robson Pederiva. "Experimental Non-Linear Model Updating Applied in Cylindrical Journal Bearings." In ASME 2001 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/detc2001/vib-21549.
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Abstract The present paper proposes the use of non linear model updating applying unrestricted optimization method, in order to obtain a methodology, which allows the calibration of mathematical models in rotating systems. An experimental set up for this purpose consists of a symmetric rotor, on a rigid foundation supported by two hidrodynamic cylindrical bearings and with a central disk of considerable mass, working as na unbalancing excitation force. Once the numeric and experimental values are obtained, error vectors are defined, which are the minimization parameters, through the variation of the numeric model parameters. The method presented satisfactory results, as it was able to calibrate the mathematical model, and then to obtain reliable responses for the physical system studied. The research also presents a contribution for the rotating machine desing area as it presents a relatively simple methodology on the updating and revalidation of computacional models for machines and structures.
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Coelho, Leandro dos Santos, and Viviana Cocco Mariani. "Discrete Variable Structure Control Based on Optimization by Cultural Differential Evolution Approach." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15554.
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Advanced conceptions to design industrial control systems are, in general, dependent of mathematical models of the controlled process. Also, the task of the controllers is to achieve an optimum performance when facing with various types of disturbances that are, sometimes, unknown in practical applications. An advanced methodology for control design is the variable structure control (VSC) with sliding mode. This paper considers the non-linear control of industrial processes based on self-tuning discrete VSC technique. A novel and systematic VSC design methodology is proposed, which integrates an estimator based on recursive least square algorithm, a discrete quasi-sliding surface and a optimization method. Contrary to the trial and error selection of the variable structure feedback gains reported in the literature, the selection in present work is done using differential evolution (DE) optimization, an evolutionary computation technique, with a new operator based on normative knowledge of cultural algorithms. The proposed design has been applied to a control valve described by a non-linear Wiener model. Numerical simulation results reveal that the new DE approach is applicable and promising for the VSC design.
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Narimani, A., and M. F. Golnaraghi. "Modeling and Control of Magnetorheological Dampers for Vibration Isolation." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42467.
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Semi-active isolators offer significant improvement in performance over passive isolators. These systems benefit from the advantages of active systems with the reliability of the passive systems. In this work we study a vibration isolation system with a magnetorheological (MR) damper. The experimental investigation of the mechanical properties of a commercially available linear MR damper (RD-1005-3) was conducted next. The mathematical Bouc-Wen model was adopted to predict the performance of MR damper. In addition, a modified Bingham model has been developed to characterize the damper behavior more accurately and efficiently. The measured hysteresis characteristics of field-dependent damping forces are compared with the simulation results from the described mathematical models. The accuracy of a damping-force controller using the proposed method is also demonstrated experimentally. Finally, a scaled quarter car model is set up to study the performance of the control strategy. The experimental results show that with the semi-active control the vibration of the quarter car model is well controlled.
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Usubamatov, Ryspek, Tan Chan Sin, and Mohd Fidzwan B. Md Amin Hamzas. "Productivity Theory for Industrial Automated Lines." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62722.
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The basic attributes of any industrial machines and systems are productivity rate and quality of products. Attributes of productivity are related to the theory of reliability let alone the theory of efficiency of machines. Publications in area of productivity of the industrial systems enable to write the productivity theory for the industrial machines and systems. This theory shows the links between productivity, reliability, technological and technical parameters and the structure of machines with complex designs. Automated production lines are considered industrial systems for the collection of serial and parallel stations arranged according to a certain structure that depends on a technological process of machining parts. Manufacturers require correct and clear mathematical models to calculate the productivity of the automated lines with high accuracy. The mathematical models for productivity rate of industrial systems with complex design define their structures according to the level of output. This paper presents an analytical approach to the productivity rate of automated lines with stations and mechanisms that display different failure rates and processing times. The typical designs of industrial automated lines are considered by three types of structure: multi-station ’s automated line of serial, parallel action and serial-parallel action. All designs can be presented using linear, circular and rotary arrangements. The analytical equations allow for the output of the automated lines to be modeled with different failure rates for the stations and mechanisms yielding results close to the actual productivity values.
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Weber Martins, Thiago, Katharina Albrecht, and Reiner Anderl. "Automated Import of XML-Files Containing Optimized Geometric Data to 3D-CAD-Models of Non-Linear Integral Bifurcated Sheet Metal Parts." In ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-47076.
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The Collaborative Research Centre 666 has the focus on researching fundamental new methods for the development of optimized products and production processes for integral bifurcated sheet metal parts. Technological innovations have been achieved with respect to new production processes such as linear flow splitting and linear bend splitting as well as to produce products with flexible profiles. The use of state of art product development methodologies can be applied but these are not optimized to deal with the high complexity of the requirements and properties of integral bifurcated sheet metal products. In order to deal with that complexity a new approach of a product development methodology, the algorithm based product development process, has been established. Within the scope of the algorithm based product development methodology a topology optimization, based on mathematical algorithms using product requirements information, is already applied in the conceptual steps of product development process. By using this methodological approach an optimized concept of bifurcated sheet metal can be determined. The results are stored as optimized geometric data in XML-format files. 3D-CAD-Models are generated based on these data. However the import of these data into 3D-CAD-Systems are not fully automated. The developed data model, from earlier works for linear flow splitting and linear bend splitting, does not take into account the variability of the profiles in the third-dimension. In addition the topology optimization does not provide production-orientated design requirements and therefore it does not take into account the production process limits (of linear flow splitting and linear bend splitting). Hence 3D-CAD-Models resulting from the optimized geometric data need to be adapted manually. Therefore new advanced approaches in terms of virtual product development tools need to be explored. This paper describes the development of an interface within the CAD-System Siemens NX which supports the automatic import of XML-files containing the optimized geometric data of non-linear integral bifurcated sheet metal in 3D-CAD-Models. The existing data model is extended considering the requirements of the developed interface in order to represent nonlinear bifurcated profiles. An approach of the interface using the described data model and the NX Open API is introduced and explained.
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Verulkar, Adwait, Corina Sandu, Daniel Dopico, and Adrian Sandu. "Direct Sensitivity Analysis of Spatial Multibody Systems With Joint Friction Using Index-1 Formulation." In ASME 2021 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/detc2021-68777.
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Abstract Sensitivity analysis is one of the most prominent gradient based optimization techniques for mechanical systems. Model sensitivities are the derivatives of the generalized coordinates defining the motion of the system in time with respect to the system design parameters. These sensitivities can be calculated using finite differences, but the accuracy and computational inefficiency of this method limits its use. Hence, the methodologies of direct and adjoint sensitivity analysis have gained prominence. Recent research has presented computationally efficient methodologies for both direct and adjoint sensitivity analysis of complex multibody dynamic systems. The contribution of this article is in the development of the mathematical framework for conducting the direct sensitivity analysis of multibody dynamic systems with joint friction using the index-1 formulation. For modeling friction in multibody systems, the Brown and McPhee friction model has been used. This model incorporates the effects of both static and dynamic friction on the model dynamics. A case study has been conducted on a spatial slider-crank mechanism to illustrate the application of this methodology to real-world systems. Using computer models, with and without joint friction, effect of friction on the dynamics and model sensitivities has been demonstrated. The sensitivities of slider velocity have been computed with respect to the design parameters of crank length, rod length, and the parameters defining the friction model. Due to the highly non-linear nature of friction, the model dynamics are more sensitive during the transition phases, where the friction coefficient changes from static to dynamic and vice versa.
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Yerlikaya, Ümit, and R. Tuna Balkan. "Dynamic Modeling and Control of an Electromechanical Control Actuation System." In ASME 2017 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/dscc2017-5056.
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Electromechanical actuators are widely used in miscellaneous applications in engineering such as aircrafts, missiles, etc. due to their momentary overdrive capability, long-term storability, and low quiescent power/low maintenance characteristics. This work focuses on electromechanical control actuation systems (CAS) that are composed of a brushless direct current motor, ball screw, and lever mechanism. In this type of CAS, nonlinearity and asymmetry occur due to the lever mechanism itself, saturation limits, Coulomb friction, backlash, and initial mounting position of lever mechanism. In this study, both nonlinear and linear mathematical models are obtained using governing equations of motion. By using the linear model, it is shown that employing a PI-controller for position and a P-controller for velocity will be sufficient to satisfy performance requirements in the inner-loop control of an electromechanical CAS. The unknown controller parameters and anti-windup coefficient are obtained by the Optimization Tools of MATLAB using nonlinear model. Results obtained from the nonlinear model and real-time unloaded and loaded tests on a prototype developed are compared to verify the nonlinear model.
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Thuanboon, Swieng, David S. Tordonato, William Navidi, David L. Olson, Brajendra Mishra, and Ge Wang. "A Statistical Analysis of Corrosion Wastage of Transverse Members in Single Hull Tankers." In 25th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/omae2006-92665.
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Corrosion wastage of structural members in oil tankers over the time causes variability in structural properties. Corrosion is a function of many variables and uncertainties, such as the types of corrosion protection systems used, types of cargo, temperature, humidity, etc. The traditional engineering and analysis, which uses simplified deterministic approaches to account for this time-dependent reliability or risk of aging ship structure, is not suitable. This investigation explores the use of statistical analysis approaches to predict corrosion wastage in oil carrying tankers. Corrosion wastage measurements from transverse members of 115 oil tankers were collected to add to an extensive corrosion wastage database. Lognormal function was found to best fit the collected data when compared to other methods, such as the Weibull function. Linear regression in the form of three mathematical models of corrosion wastage, developed by considering age of ship, coating life, and the location of the transverse members, is used to indicate the relationship between corrosion wastage and age of ship. Corrosion rates were determined by the derivatives of the corrosion wastage. The results show that corrosion wastage may accelerate after twenty years of service. It is expected that the study will help identify which structural members may be more susceptible to corrosion wastage and require more frequent inspection.