Introduction to Modeling and Simulation Techniques

Modeling and simulation techniques are becoming an important research method for investigating operational and organizational systems. Many literatures report different aspects and views of modeling and simulation but there is little literature that covers a full cycle of modeling and simulation, including both model design & development and model verification & validation, for use in industrial product development systems. This paper introduces modeling and simulation concepts, methods and tools, and discusses approaches that can be used for model verification and validation. A modeling and simulation procedure, designed for use in understanding industrial product development systems, is introduced that accommodates both model creation and verification & validation. The overall goal of the research is to bridge the gap between model design & development and model verification & validation in a modeling and simulation procedure which, as a whole, is essential for the application of modeling and simulation techniques to understand any real-world system

Modeling and Simulating Vicious Circles Problems

Time and cost overruns in new product development processes are often attributed to low quality information communication in early stages of the process when key decisions are made by individuals who have limited understanding of how micro-level decision-making can significantly affect macro-level system performance, that eventually leads to the phenomenon of “vicious circles” in new product development processes. Agent-based simulation is a promising approach that can be applied to understand complex systems, such as new product development processes. This paper reports an application of agent-based simulation to time-related aspects of vicious circles in a new product development process case study from a large UK-based manufacturing company. A simulation model was developed following an experimental method established in the research. In the model, work teams and their activities and contributions to the process are represented by autonomous agents. Initial simulation results showed agent-based simulation is an effective and efficient approach for understanding and studying vicious circles in new product development processes

Agent-Based Simulation New Product Development Processes

New Product Development Processes (NPDP) involve a series of functional teams who work in a complex information communication network. Agent-Based Simulation (ABS) comprises a set of autonomous agents that act and interact complying with simulation specifications within a simulation world. This paper analyzes key features of both new product development processes and agent-based simulation. A simulation mapping is introduced to highlight mirror relationships between key elements of new product development processes and key concepts that underpin agent-based simulation. We introduce a new product development process case study arising from a large UK-based manufacturing company, and an agent-based simulation model to represent the new product development process. Simulation results show that agent-based simulation is a promising method to study and explore complex socio-technical systems such as new product development processes

Uma solução de implantação auto-adaptativa para plataformas Android

Orientador: Cecília Mary Fischer RubiraDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: Os dispositivos móveis, hoje em dia, fornecem recursos semelhantes aos de um computador pessoal de uma década atrás, permitindo o desenvolvimento de aplicações complexas. Consequentemente, essas aplicações móveis podem exigir tolerar falhas em tempo de execução. No entanto, a maioria das aplicações móveis de hoje são implantados usando configurações estáticas, tornando difícil tolerar falhas durante a sua execução. Nós propomos uma infraestrutura de implantação auto-adaptativa para lidar com este problema. A nossa solução oferece um circuito autônomo que administra o modelo de configuração atual da aplicação usando um modelo de características dinâmico associado com o modelo arquitetônico da mesma. Em tempo de execução, de acordo com a seleção dinâmica de características, o modelo arquitetônico implantado na plataforma se re-configura para fornecer uma nova solução. Uma aplicação Android foi implementada utilizando a solução proposta, e durante sua execução, a disponibilidade de serviços foi alterada, de tal forma que sua configuração corrente foi dinamicamente alterada para tolerar a indisponibilidade dos serviçosAbstract: Mobile devices, nowadays, provide similar capabilities as a personal computer of a decade ago, allowing the development of complex applications. Consequently, these mobile applications may require tolerating failures at runtime. However, most of the today¿s mobile applications are deployed using static configurations, making difficult to tolerate failure during their execution. We propose an adaptive deployment infrastructure to deal with this problem. Our solution offers an autonomic loop that manages the current configuration model of the application using a dynamic feature model associated with the architectural model. During runtime, according to the dynamic feature selection, the deployed architectural model can be modified to provide a new deployment solution. An Android application was implemented using the proposed solution, and during its execution, the services availability was altered so that its current configuration was changed dynamically in order to tolerate the unavailability of servicesMestradoCiência da ComputaçãoMestre em Ciência da Computação131830/2013-9CNP

Toward Customizable Multi-tenant SaaS Applications

abstract: Nowadays, Computing is so pervasive that it has become indeed the 5th utility (after water, electricity, gas, telephony) as Leonard Kleinrock once envisioned. Evolved from utility computing, cloud computing has emerged as a computing infrastructure that enables rapid delivery of computing resources as a utility in a dynamically scalable, virtualized manner. However, the current industrial cloud computing implementations promote segregation among different cloud providers, which leads to user lockdown because of prohibitive migration cost. On the other hand, Service-Orented Computing (SOC) including service-oriented architecture (SOA) and Web Services (WS) promote standardization and openness with its enabling standards and communication protocols. This thesis proposes a Service-Oriented Cloud Computing Architecture by combining the best attributes of the two paradigms to promote an open, interoperable environment for cloud computing development. Mutil-tenancy SaaS applicantions built on top of SOCCA have more flexibility and are not locked down by a certain platform. Tenants residing on a multi-tenant application appear to be the sole owner of the application and not aware of the existence of others. A multi-tenant SaaS application accommodates each tenant’s unique requirements by allowing tenant-level customization. A complex SaaS application that supports hundreds, even thousands of tenants could have hundreds of customization points with each of them providing multiple options, and this could result in a huge number of ways to customize the application. This dissertation also proposes innovative customization approaches, which studies similar tenants’ customization choices and each individual users behaviors, then provides guided semi-automated customization process for the future tenants. A semi-automated customization process could enable tenants to quickly implement the customization that best suits their business needs.Dissertation/ThesisDoctoral Dissertation Computer Science 201

Simulating vicious circles in new product introduction systems

New product introduction systems are complex socio-technical systems that are used to design, develop, and deliver products and services to users. Lack of design information within such systems results in uncertainties that have an adverse effect on the performance of the whole system by creating a need for rework. Typical performance measurements for new product introduction systems are time, cost, and quality. Rework has a significant influence on time-related aspects of system performance because it consumes additional time resource that could otherwise be dedicated to other activities such as the development of new products. Rework reduces time resource available for information communication which in turn leads to more rework in the future. This results in vicious circles where limited time leads to more rework which further detracts from time to devote to other tasks in the future. Vicious circles have previously been reported in societal systems. The goal of this research was to apply modelling and simulation techniques to understand time-related aspects of the vicious circles phenomenon in new product introduction systems and explore potential management interventions to mitigate the consequences of vicious circles. A case study from an international manufacturing organisation was used to inform the development of a simulation mapping between key elements of the new product introduction system and key concepts that underpin agent-based simulation methods. A simulation model was developed to represent vicious circles in the case study, based on the simulation mapping. The simulation model was verified and validated through a series of seven experiments. Four further simulation experiments were then carried out. The first two experiments explored the impact of different prioritisations of responding to information requests on time-related aspects of the system performance. Results highlighted the importance of prioritising responses to information requests which significantly reduced rework volumes in the model. The final two experiments explored the balancing of time taken for individual product development activities and resources used. In simulations with low response rates, one means to avoid system collapse was to extend the time allowed for product development. Given the need to deliver products to market as quickly as possible, a final experiment explored ways to speed up product development to eliminate adverse effects on product development cycle time. By reducing the time taken to respond to requests, which in a real world system could be achieved in a number of ways, e.g. improving team size or design capability, the product development cycle could be shortened