A Hybrid Model for Dynamic Simulation of Custom Software Projects in a Multiproject Environment

This paper describes SimHiProS, a hybrid simulation model of software production. The goal is to gain insight on the dynamics induced by resource sharing in multiproject management. In order to achieve it the hierarchy of decisions in a multiproject organization is modeled and some resource allocation methods based on algorithms from the OR/AI domain are used. Other critical issues such as the hybrid nature of software production and the effects of measurement and control are also incorporated in the model. Some first results are presented.Ministerio de Ciencia e Innovación TIN2004-06689-C03-03Ministerio de Ciencia e Innovación TIN2007-67843-C06-0

Simulación híbrida: caso de estudio en un filtro activo de potencia

El concepto de simulación hibrida consiste en la combinación de simulaciones por computador y pruebas de laboratorio físicas. Este enfoque es una alternativa rentable a las pruebas físicas de todo un sistema, y permite la mejor comprensión de los complejos sistemas acoplados. Este artículo describe la implementación de un prototipo híbrido de filtro activo de potencia (APF), donde se implementa el sistema de fuente y la carga en simulación en tiempo real, y el sistema de convertidor de energía estática que actúa como filtro activo de potencia se implementa en hardware. Además, se confirman los resultados de simulación híbrida con la implementación de la simulación numérica en MATLAB-Simulink del mismo sistema implementado en la etapa de análisis y diseño del filtro activo de potencia.The hybrid simulation concept consisting of a combination of computer simulation and laboratory tests. This approach is a cost effective alternative to physically testing the whole system and allows better understanding of complex coupled systems.This paper describes implementing an active power filter (APF) hybrid prototype where the source system and load are implemented as a real-time simulation and the system of static power converter acting as an active power filter is implemented in physical hardware. It also confirmed the hybrid simulation results by implementing the simulation in MATLAB-Simulink regarding the same system implemented during the active power filter analysis and design stage

Exploring the Software Verification and Validation Process with Focus on Efficient Fault Detection

Quality is an aspect of high importance in software development projects. The software organizations have to ensure that the quality of their developed products is what the customers expect. Thus, the organizations have to verify that the product is functioning as expected and validate that the product is what the customers expect. Empirical studies have shown that in many software development projects as much as half of the projected schedule is spent on the verification and validation activities. The research in this thesis focuses on exploring the state of practice of the verification and validation process and investigating methods for achieving efficient fault detection during the software development. The thesis aims at increasing the understanding of the activities conducted to verify and validate the software products, by the means of empirical research in the software engineering domain. A survey of eleven Swedish software development organizations investigates the current state of practice of the verification and validation activities, and how these activities are managed today. The need for communicating and visualising the verification and validation process was expressed during the survey. Therefore the usefulness of process simulations was evaluated in the thesis. The simulations increased the understanding of the relationships between different activities among the involved participants. In addition, an experiment was conducted to compare the performance of the two verification and validation activities, inspection and testing. In the future work, empirical research, including experiment results, will be used for calibration and validation of simulation models, with focus on using simulation as a method for decision support in the verification and validation process

Modelling future demand for long-term care

This research was jointly funded by the Economic and Social Research Council (ESRC) and the Engineering and Physical Sciences Research Council (EPSRC). As such, its underpinning and innovative aim was to explore the use of Operational Research (OR) techniques, a research area traditionally associated with the EPSRC, to address key societal problems traditionally associated with the ESRC.The ageing population presents many significant challenges for social care services at both a national and local level, one of which is to meet the demand for long-term care. The population of people aged over 65 will continue to grow for some time as the ?baby boom? generation ages. The concern for policy planners is whether there will be enough resources in place to handle the expected strain on the system in the future. The research presented in this thesis addresses this key issue, and was carried out in collaboration with the Adult Services Department of Hampshire County Council (HCC). The overarching aim of this thesis was to develop computer models (using data local to Hampshire) which would be of practical use in estimating the future demand and planning the supply of long-term care in Hampshire.A cell-based model was built to forecast the demand for long-term care in Hampshire from people aged 65 and over for the period 2009 to 2026. An important part of this research was to understand the main drivers of future demand for long-term care and to predict the future number of people with a disability. Hampshire County Council has already tried to address these issues of demographic change through a modernisation programme. Part of this has been the establishment of a contact centre called Hantsdirect. A discrete-event simulation model of the contact centre was developed. The two models were combined to explore the short- and long-term performance of the contact centre in the light of demographic change. This hybrid model has enabled HCC to explore the short- and long-term performance of the contact centre.This study combines OR with Gerontology, Demography and Social Policy. This research is novel as it iteratively combines a compartmental population model with a discrete-event simulation model. From an OR perspective, the aim was not only to explore the use of modelling in social care (where, unlike healthcare, there has not hitherto been a lot of research), but also to investigate the potential for combining different modelling approaches in order to obtain additional value from the modelling. This novel approach in a social care setting is one of the main contributions of this thesis

A Framework to Evaluate Candidate Agile Software Development Processes

University of Minnesota Ph.D. dissertation. July 2019. Major: Computer Science. Advisors: Mats Heimdahl, Sanjai Rayadurgam. 1 computer file (PDF); vii, 108 pages.Today's software development projects must respond to fierce competition, a constantly changing marketplace, and rapid technological innovation. Agile development processes are popular when attempting to respond to these changes in a controlled manner; however, selecting an ill-suited process may increase project costs and risk. Before adopting a seemingly promising Agile approach, we desire to evaluate the approach's applicability in the context of the specific product, organization, and staff. Simulation provides a means to do this. Because of Agile's emphasis on the individual and interactions, we theorize that a high-fidelity model---one that models individual behavior---will produce more accurate outcome predictions than those that do not account for individual behavior. To this end, we define criteria, based on the Agile Manifesto, for determining if a simulation is suited to model Agile processes and use the criteria to assess existing simulations (and other evaluation frameworks). Finding no suitable evaluation framework, we focus on constructing a simulation that satisfies our criteria. In this work, we propose a process simulation reference model that provides the constructs and relationships needed to capture the interactions among the individuals, product, process, and project in a holistic fashion. As a means for evaluating both our criteria and reference model, we constructed the Lean/Agile Process Simulation Environment (LAPSE), a multi-agent simulation framework for evaluating Agile processes prior to adoption within an organization. The contributions of this work are threefold. Building on the simulation assessment criteria of Kellner, Madachy, and Raffo and the Agile Manifesto, we establish criteria for assessing Agile simulations. From there, we define a reference model that captures the constructs and relationships needed to simulate Agile processes. We then show the satisfiability of our criteria and demonstrate how the constructs of the reference model fit together by building LAPSE. This work lays the groundwork for detailed a priori process evaluation and enables future research into process transformation

Process software simulation model of Lean-Kanban Approach

Software process simulation is important for reducing errors, helping analysis of the risks and for improving software quality. In recent years, the Lean-Kanban approach has been widely applied in software practice including software development and maintenance. The Lean-Kanban approach minimizes the Work-In-Progress (WIP), which is the number of items that are worked on by the team at any given time. It has been demonstrated that such approach can help to improve software maintenance and development processes in industrial environments. The goal of the simulation model itself is to increase the understanding and to support decisions for planning such kind of projects. Considering the threats to validity of the study, the accuracy and reliability of the simulation model could be shown and the simulation model implementation allows for deriving hypothesis on the impact of distribution on parameters such as throughput. In this thesis, we describe our simulation studies, which show that the Lean-Kanban approach can indeed help to reduce the average time needed to complete maintenance or development issues. This simulation model can simulate existing maintenance and development processes that does not use a WIP limit, as well as a maintenance and development processes that adopt a WIP limit. We performed some case studies using real data collected from different projects. The results confirmthat the WIP-limited process as advocated by the Lean- Kanban approach could be useful to increase the efficiency of software maintenance and development, as reported in previous industrial practices

Process software simulation model of Lean-Kanban Approach

Software process simulation is important for reducing errors, helping analysis of the risks and for improving software quality. In recent years, the Lean-Kanban approach has been widely applied in software practice including software development and maintenance. The Lean-Kanban approach minimizes the Work-In-Progress (WIP), which is the number of items that are worked on by the team at any given time. It has been demonstrated that such approach can help to improve software maintenance and development processes in industrial environments. The goal of the simulation model itself is to increase the understanding and to support decisions for planning such kind of projects. Considering the threats to validity of the study, the accuracy and reliability of the simulation model could be shown and the simulation model implementation allows for deriving hypothesis on the impact of distribution on parameters such as throughput. In this thesis, we describe our simulation studies, which show that the Lean-Kanban approach can indeed help to reduce the average time needed to complete maintenance or development issues. This simulation model can simulate existing maintenance and development processes that does not use a WIP limit, as well as a maintenance and development processes that adopt a WIP limit. We performed some case studies using real data collected from different projects. The results confirmthat the WIP-limited process as advocated by the Lean- Kanban approach could be useful to increase the efficiency of software maintenance and development, as reported in previous industrial practices

Submission to ProSim 2000 Workshop Hybrid Simulation Modelling of the Software Process

The paper proposes the combination of three traditional modelling methods (analytical, continuous and discrete-event) into a unique hybrid two-level modelling approach to address software process simulation modelling issues. At the higher abstraction level, the process is modelled by a discrete-event queuing network, which represents the component activities (i.e. service stations), their interactions, and the exchanged artifacts. At the lower abstraction level, the analytical and continuous methods are used to describe the implementation details of the introduced activities. The hybrid approach is applied to a waterfall-based software process to study the effects of requirements instability on various process quality attributes, as effort, delivery time, productivity, rework percentage, and product quality. Simulation results show that the use of the model can provide both qualitative and quantitative suggestions on how to improve the software process or to satisfy specific organisational needs. 1