Discrete event simulation (DES) produces models of greater granularity and higher accuracy in analysis of heavy construction operations than classic quantitative techniques;specifically utilizing average production ra...
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ISBN:
(纸本)9781479939503;9781479920778
Discrete event simulation (DES) produces models of greater granularity and higher accuracy in analysis of heavy construction operations than classic quantitative techniques;specifically utilizing average production rates for determining the fleet required for and duration of earthmoving operations. Nonetheless, the application of DES is not readily applied beyond academic work for high level analysis in the heavy construction industry. Field level planners default to the use of average production rates, which can be easily applied with simple spreadsheet tools and allows quick recalculations to be performed when existing input data is changed or more data becomes available. To aid in fleet selection and determination of the duration of site grading earthworks operations where one fleet is applied, this research presents a new approach by developing quantitative formulas from DES analysis. The approach simplifies DES application and reduces the barrier to access simulation-generalized and field-applicable knowledge, while providing greater accuracy than simply relying on average production
Industrial construction projects have recently moved more towards tighter schedules and fast-tracked engineering and construction. This leads to overlap between work packages, increased occurrences of resource over-al...
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ISBN:
(纸本)9781479939503;9781479920778
Industrial construction projects have recently moved more towards tighter schedules and fast-tracked engineering and construction. This leads to overlap between work packages, increased occurrences of resource over-allocation and site congestion, which pose challenges to project planners in scheduling construction works and dynamically allocating resources considering the construction site conditions. Most previous research related to scheduling and resource allocation assumes that allocated resources remain consistent throughout the execution of work packages. This paper presents a workface planning system that allows for variable resource allocation and variable durations in execution of a work package, while holding logic relationships and space congestion constraints. A case study from a real industrial project is presented and results show that the proposed system reduces resource idle time as well as returns shorter project duration than traditional scheduling approaches.
In semiconductor high-mix fabs, several technology nodes are run on the same line, using tool types from different generations. In this context, processability is a function defining which products can be processed on...
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ISBN:
(纸本)9781479939503;9781479920778
In semiconductor high-mix fabs, several technology nodes are run on the same line, using tool types from different generations. In this context, processability is a function defining which products can be processed on a given machine considering the current status of both the product and the machine. So in a high-mix context, having an information system that provides reliable information on processability and that can support the evolution of processability rules is fundamental. In this paper, we analyze the key elements for such a system. Based on the example of the implementation of fab constraints at STMicroelectronics' Crolles300 production unit, we illustrate the consequences of the integration of new processability rules and propose flexible and agile UML class diagrams enabling information system to meet evolution requirements. The approach is validated on real fab data, and its impact is discussed.
Difficulty of social phenomena representation can be related to limitations of used modeling techniques. More flexibility and creativity to represent social phenomena (an adequate mix of model scope, resolution, and f...
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ISBN:
(纸本)9781479939503;9781479920778
Difficulty of social phenomena representation can be related to limitations of used modeling techniques. More flexibility and creativity to represent social phenomena (an adequate mix of model scope, resolution, and fidelity) is desirable. The representation of social phenomena with a combination of different methods seems intuitively appealing, but the usefulness of this approach is questionable. Current view on the justification of multi-method has limitations in social science context, because it lacks a human dimension. This paper explores the literature that pertains to mixing methods, and displays current reasoning behind the use of the multi-method approach. The perspective on mixing methods from empirical social science projected onto M&S domain exposes high-level purposes related to representation of social phenomena with mixed method approaches. Based on the reviewed literature and qualitative analysis, the general view of ingredients for inferring purposefulness of the multi-method approach in the context of social phenomena representation is proposed.
This paper describes an analysis of emissions of carbon monoxide (CO) using a discrete event simulator of open source. A simulation model was built to evaluate gas emissions emitted by a fleet of trucks during transpo...
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In several applications arising in compute science, cascade theory, and other applied areas, it is of interest to evaluate the tail probabilities of non-homogeneous stochastic fixed point equations. Recently, techniqu...
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ISBN:
(纸本)9781479939503;9781479920778
In several applications arising in compute science, cascade theory, and other applied areas, it is of interest to evaluate the tail probabilities of non-homogeneous stochastic fixed point equations. Recently, techniques have been developed for the related linear recursions, yielding tail estimates and importance sampling methods for these recursions. However, such methods do not routinely generalize to non-homogeneous recursions. Drawing on techniques from the weighted branching process literature, we present a consistent, strongly efficient importance sampling algorithm for estimating the tail probabilities for the case of non-homogeneous recursions.
Recently, the growth of outpatient clinic capacity has not matched the increasing demand on outpatient clinics, which has led to long waiting times for patients and overtime work for clinic staff. This has three signi...
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ISBN:
(纸本)9781479939503;9781479920778
Recently, the growth of outpatient clinic capacity has not matched the increasing demand on outpatient clinics, which has led to long waiting times for patients and overtime work for clinic staff. This has three significant negative effects on patients and staff: (1) patients' distrust of the procedures for treating outpatients increases, (2) nurses' stress from patient complaints increases, and (3) doctors' pressure to shorten treatment times while maintaining high levels of service quality increases. Presented in this paper is a simulation-based operation management method that provides the stakeholders with future visibility in outpatient departments. The future visibility is obtained from the current situation of the outpatient department using a simulation-based scheduling system and is shared by a business process management system that informs patients of their expected waiting time in order to lower the workload and pressure on clinic staff and to allow staff to manage exceptions proactively.
July 1, 2013 will usher in new revisions to the current Federal Motor Carrier Safety Administration's Hours of Service (HOS) regulations governing hours of service for drivers of Commercial Motor Vehicles. This pa...
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ISBN:
(纸本)9781479939503;9781479920778
July 1, 2013 will usher in new revisions to the current Federal Motor Carrier Safety Administration's Hours of Service (HOS) regulations governing hours of service for drivers of Commercial Motor Vehicles. This paper will chronicle the modeling approach and preliminary results of the performance impact of the two most significant 2013 HOS regulation changes on a large random over-the-road (OTR) trucking fleet operating in North America. The ultimate goal of this modeling analysis was to provide data to quantify the pending impact of the regulation changes to guide company strategies to mitigate risk and provide a foundation for proactive customer communications. The simulation model was successfully validated by comparing simulated fleet performance against actual fleet performance. Results have been used to communicate impact to internal company stake holders, industry analysts, and customers, along with prompting detailed fleet studies to identify strategies to minimize impact to high risk customers.
Today, information systems are threatened not only by the opportunistic exploitation of particular technical weaknesses, but increasingly by targeted attacks that combine multiple vectors to achieve the attacker's...
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ISBN:
(纸本)9781479939503;9781479920778
Today, information systems are threatened not only by the opportunistic exploitation of particular technical weaknesses, but increasingly by targeted attacks that combine multiple vectors to achieve the attacker's objectives. Given the complexities involved, identifying the most appropriate measures to counteract the latter threats is highly challenging. In this paper, we introduce a novel simulation-optimization method that tackles this problem. It combines rich conceptual modeling of security knowledge with discrete event simulation and metaheuristic optimization techniques. By simulating attacks, the method infers possible routes of attack and identifies emergent weaknesses while accounting for adversaries' heterogeneous objectives, capabilities, and available modes of entry. The optimization iteratively adapts the system model by means of a genetic algorithm and optimizes its ability to detect ongoing attacks and prevent their successful execution. We describe a prototypical implementation and illustrate its application by means of scenarios for five types of adversaries.
Massive concrete dam projects will be conducted in the next ten years to respond to the increasing demand for clean energy and water resources in developing countries. With more attention paid to environmental issues,...
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ISBN:
(纸本)9781479939503;9781479920778
Massive concrete dam projects will be conducted in the next ten years to respond to the increasing demand for clean energy and water resources in developing countries. With more attention paid to environmental issues, there is an increasing need to develop a methodology for reliably predicting the integrated performance of cost, schedule and emission factors in the planning stage. In this paper, we propose a methodology for using discrete event simulation (DES) for dam construction processes to enhance the performance dynamically. A case study is conducted to demonstrate the effectiveness of the DES model, which is validated by the actual cumulative progress on the construction site. The results indicate that the cost, schedule and emission performance are highly interactively correlated when using RFC in dam projects. The promoted methodology could help construction managers compare the integrated performance of different options in RFC dam constructions.
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