Simulation study for investment decisions on the EcoBoost camshaft machining line

Design/redesign of manufacturing systems is a complex, risky, and expensive task. Ford Motor Company’s Valencia Engine Plant faces this challenge as it plans to upgrade its machining and assembly lines to introduce the new EcoBoost engines. The research project described in this paper aimed to support the transition process particularly at the camshaft machining line by using simulation modelling techniques. A series of experiments was carried out using the simulation model developed, and recommendations were proposed based on the results of these experiments to support the decision as to where to invest on the line. The outcomes from the research project indicated that investment is required in terms of increasing the capacity of two bottleneck operations through retooling and improving the conveyor routing logic in one key area. Keywords: simulation modelling, closed-loop network, automotive production system

SensorCloud: Towards the Interdisciplinary Development of a Trustworthy Platform for Globally Interconnected Sensors and Actuators

Although Cloud Computing promises to lower IT costs and increase users' productivity in everyday life, the unattractive aspect of this new technology is that the user no longer owns all the devices which process personal data. To lower scepticism, the project SensorCloud investigates techniques to understand and compensate these adoption barriers in a scenario consisting of cloud applications that utilize sensors and actuators placed in private places. This work provides an interdisciplinary overview of the social and technical core research challenges for the trustworthy integration of sensor and actuator devices with the Cloud Computing paradigm. Most importantly, these challenges include i) ease of development, ii) security and privacy, and iii) social dimensions of a cloud-based system which integrates into private life. When these challenges are tackled in the development of future cloud systems, the attractiveness of new use cases in a sensor-enabled world will considerably be increased for users who currently do not trust the Cloud.Comment: 14 pages, 3 figures, published as technical report of the Department of Computer Science of RWTH Aachen Universit

DEFINING AND EVALUATING AGILE CONSTRUCTION MANAGEMENT FOR REDUCING TIME DELAYS IN CONSTRUCTION

Both competitive market forces and growing societal needs have triggered the demand for rapid delivery of construction projects, or at a minimum, for projects completed on schedule. However, schedule delays are common and recurring in construction, inevitably resulting in rework, cost overruns and legal claims. As projects become increasingly complicated, delays arise in a more unpredictable manner. The initial motivation for this research is to explore a systematic flexibility to deal with delays caused by complex changes in construction and meanwhile enhance the overall project performance. Accordingly, agile construction management is proposed in terms of a conceptual framework. Derived from agile theories in other engineering disciplines, agile management is an integrated method that allows projects thrive in a fluid environment by applying agile enablers (approaches) throughout the project lifecycle. Since agility and relevant theories are emerging in construction, the proposed agile ideas and enablers are verified by qualitative interviews with construction professionals. With ultimate goal of reducing delays, a case study is conducted investigating how much delays could be reduced if the agile enablers were used

Testing in the incremental design and development of complex products

Testing is an important aspect of design and development which consumes significant time and resource in many companies. However, it has received less research attention than many other activities in product development, and especially, very few publications report empirical studies of engineering testing. Such studies are needed to establish the importance of testing and inform the development of pragmatic support methods. This paper combines insights from literature study with findings from three empirical studies of testing. The case studies concern incrementally developed complex products in the automotive domain. A description of testing practice as observed in these studies is provided, confirming that testing activities are used for multiple purposes depending on the context, and are intertwined with design from start to finish of the development process, not done after it as many models depict. Descriptive process models are developed to indicate some of the key insights, and opportunities for further research are suggested

Applications of biased-randomized algorithms and simheuristics in integrated logistics

Transportation and logistics (T&L) activities play a vital role in the development of many businesses from different industries. With the increasing number of people living in urban areas, the expansion of on-demand economy and e-commerce activities, the number of services from transportation and delivery has considerably increased. Consequently, several urban problems have been potentialized, such as traffic congestion and pollution. Several related problems can be formulated as a combinatorial optimization problem (COP). Since most of them are NP-Hard, the finding of optimal solutions through exact solution methods is often impractical in a reasonable amount of time. In realistic settings, the increasing need for 'instant' decision-making further refutes their use in real life. Under these circumstances, this thesis aims at: (i) identifying realistic COPs from different industries; (ii) developing different classes of approximate solution approaches to solve the identified T&L problems; (iii) conducting a series of computational experiments to validate and measure the performance of the developed approaches. The novel concept of 'agile optimization' is introduced, which refers to the combination of biased-randomized heuristics with parallel computing to deal with real-time decision-making.Las actividades de transporte y logística (T&L) juegan un papel vital en el desarrollo de muchas empresas de diferentes industrias. Con el creciente número de personas que viven en áreas urbanas, la expansión de la economía a lacarta y las actividades de comercio electrónico, el número de servicios de transporte y entrega ha aumentado considerablemente. En consecuencia, se han potencializado varios problemas urbanos, como la congestión del tráfico y la contaminación. Varios problemas relacionados pueden formularse como un problema de optimización combinatoria (COP). Dado que la mayoría de ellos son NP-Hard, la búsqueda de soluciones óptimas a través de métodos de solución exactos a menudo no es práctico en un período de tiempo razonable. En entornos realistas, la creciente necesidad de una toma de decisiones "instantánea" refuta aún más su uso en la vida real. En estas circunstancias, esta tesis tiene como objetivo: (i) identificar COP realistas de diferentes industrias; (ii) desarrollar diferentes clases de enfoques de solución aproximada para resolver los problemas de T&L identificados; (iii) realizar una serie de experimentos computacionales para validar y medir el desempeño de los enfoques desarrollados. Se introduce el nuevo concepto de optimización ágil, que se refiere a la combinación de heurísticas aleatorias sesgadas con computación paralela para hacer frente a la toma de decisiones en tiempo real.Les activitats de transport i logística (T&L) tenen un paper vital en el desenvolupament de moltes empreses de diferents indústries. Amb l'augment del nombre de persones que viuen a les zones urbanes, l'expansió de l'economia a la carta i les activitats de comerç electrònic, el nombre de serveis del transport i el lliurament ha augmentat considerablement. En conseqüència, s'han potencialitzat diversos problemes urbans, com ara la congestió del trànsit i la contaminació. Es poden formular diversos problemes relacionats com a problema d'optimització combinatòria (COP). Com que la majoria són NP-Hard, la recerca de solucions òptimes mitjançant mètodes de solució exactes sovint no és pràctica en un temps raonable. En entorns realistes, la creixent necessitat de prendre decisions "instantànies" refuta encara més el seu ús a la vida real. En aquestes circumstàncies, aquesta tesi té com a objectiu: (i) identificar COP realistes de diferents indústries; (ii) desenvolupar diferents classes d'aproximacions aproximades a la solució per resoldre els problemes identificats de T&L; (iii) la realització d'una sèrie d'experiments computacionals per validar i mesurar el rendiment dels enfocaments desenvolupats. S'introdueix el nou concepte d'optimització àgil, que fa referència a la combinació d'heurístiques esbiaixades i aleatòries amb informàtica paral·lela per fer front a la presa de decisions en temps real.Tecnologies de la informació i de xarxe

Developing Supply Chain Agility for the High-Volume and High-Variety Industry

Supply chains are under pressure to meet performance expectations under conditions in which access to the global network of suppliers and customers is fluid. Most studies accept the importance of agility to enhance performance using flexibility as a key dimension. Moreover, based on literature and empirical implications, it is essentially noticeable that there is an agreement on the need for flexibility in manufacturing to address both internal changes at the manufacturing echelon (e.g., a variation of process times) and external uncertainties (e.g., availability of ingredients, delivery schedules).However, there is a lack of adoptable metrics of manufacturing flexibility that can be used to evaluate manufacturing flexibility’s impact to enhance TH and reduce cost, both at the manufacturing echelon and the supply chain as a system as well as its impact on other echelons. Therefore, focusing on manufacturing flexibility as a competitive strategy induces a driving force for the success of the performance of supply chains. The purpose of this research is to present an applicable methodology for the evaluation of flexibility in a supply chain called Flexible Discrete Supply Chain (FDSC). The FDSC structure consists of a supplier, manufacturer, distributor, and customer as its conceptual model. Two main performance indicators – TH and cost are used to study the FDSC performance. This study utilizes four dimensions: volume, delivery, mix, and innovation (VDMI) flexibility. Quality function deployment is used to translate the dimensions of flexibility to key metrics that can be controlled in a discrete-event simulation (DES) model. The DES model is used to generate data, and for configuring VDMI metrics. The data is used for further sensitivity analysis. The developed methodology is verified and validated using data from a real case study. It is applicable to all supply chains within the FDSC criteria. This study contributes to the body of knowledge of supply chain flexibility through technical, methodical, and managerial implications. It clearly illustrated scenarios and provided guidelines for operations managers, to test among VMDI flexibility to maximize TH constrained by cost. Key directions for future research are identified

Managing requirements in market-driven software project: Agile methods view

Vrijeme do plasiranja na tržište i nedovoljno početno saznanje o potrebama dva su značajna problema po kojima se organiziranje potreba kod projekata razvijanja softvera za tržište razlikuje od projekata za softver po narudžbi. Ti se problemi mogu riješiti primjenom agilnih metodologija razvoja softvera kad se radi o tržišno orijentiranom softveru budući da Agilne metode naglašavaju dinamički pristup organiziranju potreba usko povezan s iterativnim ciklusom isporuke. U ovom radu, dinamički pristup Agilnih metoda definiranju potreba koristi se za uspješnu implementaciju složenog tržišno orijentiranog softverskog projekta.Time-to-market and insufficient initial requirements are two significant challenges that make managing requirements for market-driven software projects different from custom-made software projects. These challenges can be resolved by using agile software development methodologies for market-driven software development as agile methods put emphasis on a dynamic approach for requirement engineering which works closely with an iterative release cycle. In this study, dynamic requirement engineering approach of Agile methods was used for the successful implementation of market-driven complex software project