摘要:

This paper develops an automated approach to plan for mass tactical airborne operations. This proposed tool enables the user to properly load aircraft according to the mission and user specifications, so that the minimum amount of time is required to seize all assigned objectives. The methodology is based on a hybrid approach in which the first portion is a mathematical model that provides the optimal manifest under “perfect conditions”. This mathematical model is represented by a transportation network, and can be optimized using a transportation algorithm. The optimum solution from the mathematical model is input to a simulation model that introduces the inherent variability induced by wind conditions, drift, aircraft location and speed, and delays between jumper exit times. The simulation returns the expected, best, and worst arrival times to the assigned objectives. This hybrid approach allows a large problem to be solved efficiently with a great deal of time saving.

ISSN:0740-817X    

DOI:10.1080/07408179808966523

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The high level of complexity and cost involved in the development, testing, and implementation of software for traditional, hierarchical shop-floor control of automated manufacturing systems has motivated considerable research in recent years on the distributed shop-floor control paradigm. In this paper, we describe a methodology for modeling and simulation of an auction-based shop-floor control scheme in a parallel and distributed computing environment using the Parallel Virtual Machine software library. Compared to traditional discrete-event simulation, this approach provides a more accurate means for modeling and evaluation of the shop-floor behavior under distributed control, and enables rapid prototyping of the actual control software. We discuss the challenges and highlight research opportunities associated with modeling and simulation of distributed shop-floor control systems using parallel and distributed computing.

ISSN:0740-817X    

DOI:10.1080/07408179808966524

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper describes the development of a simulation system designed to study operating policies for discrete-part, batch-oriented manufacturing cells. Policies consist of protocols for controlling the flow of parts and workers. The need for a simulator arises from strong interactions between the configuration of system resources, part mix, worker assignment rules, and part dispatching rules. This makes analytical modeling and determination of effective universal design and operating rules difficult. The simulator has its basis in a general framework which can be used to describe operating policies. A policy is characterized by assigning appropriate values to a set of descriptive parameters. The system configuration is described by one set of parameters and operating policies by another. The framework representation of policies facilitates the development of the simulator through the application of design and analysis methods based on the Object-Oriented Programming paradigm.

ISSN:0740-817X    

DOI:10.1080/07408179808966525

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Object-oriented programming (OOP) has been revolutionizing software development and maintenance. When applied to simulation of manufacturing systems, OOP also provides an opportunity for developing new ways of thinking and modeling. In this paper, we identify existing large-scale, persistent OOP-based research efforts focusing on manufacturing system simulation, and present an integrating framework for discussing the associated modeling abstractions, implementation strategies, common themes, and distinctive features. The goal is to identify the fundamental research and application issues, assess the current state of the art, and identify key research needs.

ISSN:0740-817X    

DOI:10.1080/07408179808966526

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Although many diverse areas employ simulation models, no agreed-upon taxonomy has been developed to categorize and structure simulation models for all science and engineering disciplines. The discipline of simulation is often splintered due to this lack of structure, with ad hoc model classes such as ‘discrete event,’ ‘continuous’ and ‘combined.’ These classes most often reflect the method of execution used on a model rather than the design structure of the model. We present a uniform model design taxonomy whose categories are inspired from categories in programming language principles within the field of computer science. The taxonomy includes a set of primitive model types (conceptual, declarative, functional, constraint, spatial) and a way of integrating primitive model types together (multimodeling). These model types are discussed using a single application: a robot server for an assembly line. We have found this taxonomy enables simulators to more easily define and categorize their models as well as to understand how model types from seemingly disparate application areas are interrelated.

ISSN:0740-817X    

DOI:10.1080/07408179808966527

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

An important aspect of the vehicle routing problem (VRP) that has been largely overlooked is the use of satellite facilities to replenish vehicles during a route. When possible, satellite replenishment allows the drivers to continue making deliveries until the close of their shift without necessarily returning to the central depot. This situation arises primarily in the distribution of fuels and certain retail items. When demand is random, optimizing customer routes a priori may result in significant additional costs for a particular realization of demand. Satellite facilities are one way of safeguarding against unexpected demand. This paper presents a branch and cut methodology for solving the VRP with satellite facilities subject to capacity and route time constraints. We begin with a mixed-integer linear programming formulation and then describe a series of valid inequalities that can be used to cut off solutions to the linear programming relaxation. Several separation heuristics are then outlined that are used to generate the cuts. Embedded in the methodology is a VRP heuristic for finding good feasible solutions at each stage of the computations. Results are presented for a set of problems derived from our experience with a leading propane distributor.

ISSN:0740-817X    

DOI:10.1080/07408179808966528

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Personnel tour scheduling problems are highly relevant to service organizations and have recently received considerable attention in both theory and practice. The inherent complexity of generalized set-covering formulations (GSCFs) of personnel tour scheduling problems has often resulted in the deployment of LP-based and local-search heuristic procedures, even for relatively small problems. This paper evaluates the performance of the dual all-integer cutting plane for solving such problems. A computational study revealed that the cutting plane, enhanced by an LP objective cut and sophisticated source row selection rule, substantially outperformed a commercial branch and bound code across four sets of test problems. The study also showed that an advanced starting solution based on the LP relaxation of the GSCF generally provided more rapid convergence of the algorithm.

ISSN:0740-817X    

DOI:10.1080/07408179808966529

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We consider the optimal assignment of groups of jobs to a fixed number of time periods over a finite horizon to minimize the total facility idling and job waiting costs. The capacity of the facility varies randomly in the sense that the time that each one of the multiple servers becomes available is random (servers arrive late). The service times are also random and are independent and identically distributed. With approximations, we formulate a dynamic optimization model for this problem. With a simple modification, we can apply this dynamic model to a static outpatient appointment problem. We propose two methods to compute the capacity distribution: (1) Poisson approximation and (2) simulation. While the Poisson approximation works well for exponential service times, the simulation scheme enables us to use the dynamic model without actually specifying the service time distribution. The performance measures of the schedules obtained with these two methods compare well with those of the optimal allocation obtained from (exhaustive) simulation. We also conduct numerical studies to investigate the dynamics between the idling and waiting costs ratio and the number of scheduling periods.

ISSN:0740-817X    

DOI:10.1080/07408179808966530

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0740-817X    

DOI:10.1080/07408179808966532

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0740-817X    

DOI:10.1080/07408179808966533

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor