242 research outputs found
A State-of-the-art Integrated Transportation Simulation Platform
Nowadays, universities and companies have a huge need for simulation and
modelling methodologies. In the particular case of traffic and transportation,
making physical modifications to the real traffic networks could be highly
expensive, dependent on political decisions and could be highly disruptive to
the environment. However, while studying a specific domain or problem,
analysing a problem through simulation may not be trivial and may need several
simulation tools, hence raising interoperability issues. To overcome these
problems, we propose an agent-directed transportation simulation platform,
through the cloud, by means of services. We intend to use the IEEE standard HLA
(High Level Architecture) for simulators interoperability and agents for
controlling and coordination. Our motivations are to allow multiresolution
analysis of complex domains, to allow experts to collaborate on the analysis of
a common problem and to allow co-simulation and synergy of different
application domains. This paper will start by presenting some preliminary
background concepts to help better understand the scope of this work. After
that, the results of a literature review is shown. Finally, the general
architecture of a transportation simulation platform is proposed
Time granularity impact on propagation of disruptions in a system-of-systems simulation of infrastructure and business networks
System-of-systems (SoS) approach is often used for simulating disruptions to
business and infrastructure system networks allowing for integration of several
models into one simulation. However, the integration is frequently challenging
as each system is designed individually with different characteristics, such as
time granularity. Understanding the impact of time granularity on propagation
of disruptions between businesses and infrastructure systems and finding the
appropriate granularity for the SoS simulation remain as major challenges. To
tackle these, we explore how time granularity, recovery time, and disruption
size affect the propagation of disruptions between constituent systems of an
SoS simulation. To address this issue, we developed a High Level Architecture
(HLA) simulation of 3 networks and performed a series of simulation
experiments. Our results revealed that time granularity and especially recovery
time have huge impact on propagation of disruptions. Consequently, we developed
a model for selecting an appropriate time granularity for an SoS simulation
based on expected recovery time. Our simulation experiments show that time
granularity should be less than 1.13 of expected recovery time. We identified
some areas for future research centered around extending the experimental
factors space.Comment: 26 pages, 11 figures, 2 tables, Submitted to International Journal of
Environmental Research and Public Health: Special Issue on Cascading Disaster
Modelling and Preventio
Service-oriented architecture for device lifecycle support in industrial automation
Dissertação para obtenção do Grau de Doutor em
Engenharia Electrotécnica e de Computadores
Especialidade: Robótica e Manufactura IntegradaThis thesis addresses the device lifecycle support thematic in the scope of service oriented industrial automation domain. This domain is known for its plethora of heterogeneous equipment encompassing distinct functions, form factors, network interfaces, or I/O specifications supported by dissimilar software and hardware platforms. There is then an evident and crescent need to take every device into account and improve the agility performance during setup, control, management, monitoring and diagnosis phases.
Service-oriented Architecture (SOA) paradigm is currently a widely endorsed approach
for both business and enterprise systems integration. SOA concepts and technology
are continuously spreading along the layers of the enterprise organization envisioning
a unified interoperability solution. SOA promotes discoverability, loose coupling,
abstraction, autonomy and composition of services relying on open web standards – features that can provide an important contribution to the industrial automation domain.
The present work seized industrial automation device level requirements, constraints and needs to determine how and where can SOA be employed to solve some of the existent difficulties. Supported by these outcomes, a reference architecture shaped by distributed, adaptive and composable modules is proposed. This architecture will assist and ease the role of systems integrators during reengineering-related interventions throughout system lifecycle. In a converging direction, the present work also proposes a serviceoriented
device model to support previous architecture vision and goals by including
embedded added-value in terms of service-oriented peer-to-peer discovery and identification, configuration, management, as well as agile customization of device resources.
In this context, the implementation and validation work proved not simply the feasibility and fitness of the proposed solution to two distinct test-benches but also its relevance to the expanding domain of SOA applications to support device lifecycle in the industrial automation domain
Just-in-Time Retail Distribution:A Systems Perspective on Cross-Docking
Cross-docking is a just-in-time strategy for distribution logistics. It is aimed at reducing inventory levels and distribution lead times by creating a seamless flow of products from suppliers to customers. Prior supply chain literature has argued that creating such a seamless product flows requires a holistic view on cross-docking management, aimed at synchronizing cross-docking operations at the distribution center with its inbound and outbound network logistics. This paper provides an in-depth case study illustrating how cross-docking operations can be managed more holistically in a retail distribution context. A discrete event simulation model has been developed to understand and improve the cross-docking operations of a large grocery retailer in The Netherlands. The model is used to quantitatively evaluate two proposed changes that exploit opportunities in the design and control of the retailer’s distribution network. An extensive real-world data set is used as input to the model. Overall, the case and simulation results show that a holistic cross-docking management approach can indeed improve system-wide performance, which further stresses the importance of making cross-dock operational decisions making and network decisions together
EVAQ: Person-Specific Evacuation Simulation for Large Crowd Egress Analysis
Timely crowd evacuation in life-threatening situations such as fire emergency or terrorist attack is a significant concern for authorities and first responders. An individual’s fate in this kind of situation is highly dependent on a host of factors, especially (i) agent dynamics: how the individual selects and executes an egress strategy, (ii) hazard dynamics: how hazards propagate (e.g., fire and smoke spread, lone wolf attacker moves) and impair the surrounding environment with time, (iii) intervention dynamics: how first responders intervene (e.g., firefighters spread repellents) to recover environment. This thesis presents EVAQ, a simulation modeling framework for evaluating the impact of these factors on the likelihood of survival in an emergency evacuation. The framework captures the effect of personal traits and physical habitat parameters on occupants’ decision-making. In particular, personal (i.e., age, gender, disability) and interpersonal (i.e., agent-agent interactions) attributes, as well as an individual’s situational awareness are parameterized in a deteriorating environment considering different exit layouts and physical constraints. Further, the framework supports a variety of hazard propagation schemes (e.g., fire spreading in a given direction, lone wolf attacker targeting individuals), and intervene schemes (e.g., firefighters spreading repellents, police catch the attacker) to support a wide range of emergency evacuation scenarios. The application of EVAQ to crowd egress planning in an airport terminal and a shopping mall in the fire emergency is presented in this thesis, and results are discussed. Result shows that the likelihood of survival decreases with a decrease in availability of the nearest exits and a resulting
increase in congestions in the environment. Also, it is observed that the incorporation of group behavior increases the likelihood of survival for children, as well as elderly and disabled people. In addition, several verifications and validation tests are performed to assess the reliability and integrity of EVAQ in comparison with existing evacuation modeling tools. As personalized sensing and information delivery platforms are becoming more ubiquitous, findings of this work are ultimately sought to assist in developing and executing more robust and adaptive emergency mapping and evacuation plans, ultimately aimed at promoting people’s lives and wellbeing
A HOLISTIC APPROACH TO COMPUTER INTEGRATED MANUFACTURING ARCHITECTURE AND SYSTEMS DESIGN
This work addresses the problem of finding an improved solution to Computer
Integrated Manufacturing (ClM) Architecture and Systems Design. The current
approaches are shown to be difficult to understand and use, over complex. In
spite of their complexity of approach they lack comprehensiveness and omit many
factors and dimensions considered essential for success in today's competitive
and often global market place.
A new approach to ClM Architecture and Systems Design is presented which
offers a simpler, more flexible and more robust format for defining a particular ClM
System within a general architectural framework. At the same time this new
approach is designed to offer a comprehensive and holistic solution.
The research work involved the investigation of current approaches and research
and development initiatives focusing particularly on the CIM-OSA and GRAI
Integrated methodologies in the field of ClM Architecture. The strengths and
weaknesses of the various approaches are examined. Developments in other
related fields including manufacturing systems, manufacturing management,
information technology and systems generally have been investigated regarding
their relevance and possible contribution to an improved solution.
The author has built on his practical experience in creating, designing and
managing the implementation of a global CIM system. The authors work on
several publicly funded collaborative research and development projects relevant
to the problem area is described. These include CIM-OSA, IMOCIM and TIQS
projects. In the latter two projects the author was instrumental in developing the
methodological approach based on a systems approach to business processes in
connection with the design of quality and manufacturing systems. Both of these
projects have contributed to this work. The author has also participated in the
global IMS programme as a rapporteur for the European Commission and this
helped to provide a global perspective on the problems of manufacturing
companies as they attempt to compete in a world wide market place.
The results of this work provide the basis for a radically improved approach to
ClM Architecture and Systems Design based on the holistic view of an enterprise.
The approach developed supports the business process view of an enterprise;
addresses the people and organisational aspects; leads to ClM solutions focused
on meeting enterprise goals; and is able to deal with a significantly increased
scope and complexity compared with existing methods yet is easily understood
and more simple to simple to apply than current approaches
Cycle Time Estimation in a Semiconductor Wafer Fab: A concatenated Machine Learning Approach
Die fortschreitende Digitalisierung aller Bereiche des Lebens und der Industrie lässt die Nachfrage nach Mikrochips steigen. Immer mehr Branchen – unter anderem auch die Automobilindustrie – stellen fest, dass die Lieferketten heutzutage von den Halbleiterherstellern abhängig sind, was kürzlich zur Halbleiterkrise geführt hat. Diese Situation erhöht den Bedarf an genauen Vorhersagen von Lieferzeiten von Halbleitern. Da aber deren Produktion extrem schwierig ist, sind solche Schätzungen nicht einfach zu erstellen. Gängige Ansätze sind entweder zu simpel (z.B. Mittelwert- oder rollierende Mittelwertschätzer) oder benötigen zu viel Zeit für detaillierte Szenarioanalysen (z.B. ereignisdiskrete Simulationen). Daher wird in dieser Arbeit eine neue Methodik vorgeschlagen, die genauer als Mittelwert- oder rollierende Mittelwertschätzer, aber schneller als Simulationen sein soll. Diese Methodik nutzt eine Verkettung von Modellen des maschinellen Lernens, die in der Lage sind, Wartezeiten in einer Halbleiterfabrik auf der Grundlage einer Reihe von Merkmalen vorherzusagen. In dieser Arbeit wird diese Methodik entwickelt und analysiert. Sie umfasst eine detaillierte Analyse der für jedes Modell benötigten Merkmale, eine Analyse des genauen Produktionsprozesses, den jedes Produkt durchlaufen muss – was als "Route" bezeichnet wird – und entwickelte Strategien zur Bewältigung von Unsicherheiten, wenn die Merkmalswerte in der Zukunft nicht bekannt sind. Zusätzlichwird die vorgeschlagene Methodik mit realen Betriebsdaten aus einerWafer-Fabrik der Robert Bosch GmbH evaluiert. Es kann gezeigt werden, dass die Methodik den Mittelwert- und Rollierenden Mittelwertschätzern überlegen ist, insbesondere in Situationen, in denen die Zykluszeit eines Loses signifikant vom Mittelwert abweicht. Zusätzlich kann gezeigt werden, dass die Ausführungszeit der Methode signifikant kürzer ist als die einer detaillierten Simulation
Thirty-fourth Annual Symposium of Trinity College Undergraduate Research
2021 annual volume of abstracts for science research projects conducted by students at Trinity College
Conceptual design and simulated operation of economies of scope and scale manufacturing enterprises
Much of industry is seeking scope economies, but this requires more complex and flexible product realisation. Modelling technologies have potential to support the life cycle engineering of both Economies of Scope and Scale (EoSS) manufacturing systems. However when companies operate in dynamic environments it is not sufficient to model manufacturing systems in isolation. Rather a holistic modelling methodology is needed which can create structural and behavioural models of dependencies between the manufacturing systems, and the business and engineering environments in which they operate; so that a suitable balance between economies of scope and scale can be achieved. This thesis describes the conception and development of a step wised Extended Modelling Methodology (EMM) which facilitates reasoning, and related decision making, about EoSS manufacturing systems. The EMM was conceived from exploratory research in two SMEs, following which it was applied and case tested in a large manufacturing company. Little academic attention to date has been paid to theorising about the link between ‘Economies of Scope and Scale (EoSS) phenomenon' and ‘manufacturing systems design'. Hence many questions about EoSS manufacturing remain unanswered, such as: (1) academic communities need to know what EoSS actually means and how state-of-the-art modelling can support qualitative and quantitative analysis of EoSS system phenomenon; and (2) industry needs to know how they can benefit from EoSS, what attended costs they might incur, and what best balance between scope and scale economies can be achieved. With these general requirements in mind the thesis reports on the conception and industrial application of the EMM. This has: (A) developed new ideas about EoSS, which can be used to characterise EoSS phenomenon; (B) introduced a new way of visualising architectural aspects of EoSS at multiple-levels of abstraction; and (C) with reference to case studies has illustrated the use of multi-level modelling to enable predictions to be made about EoSS benefits and costs.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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