A simulation based decision model for a fish processing facility

The single, most important production method in the fish processing industry is quick-freezing. The quick-freezing process in a typical fish processing plant is described. The network simulation model is then developed using the imulation anguage for lternative odeling (SLAM). The results from the model include utilization of machines and workers, in-process inventory levels, and throughput times. Sensitivity analysis is performed on some of the major factors that can affect the efficiency of the system. A front-end interface to the simulation model is developed which facilitates the user in entering input parameters to the model without the need to learn the simulation language. The model provides a methodology for evaluating alternative production strategies for a fish processing facility.     

Event-driven receding horizon control for energy-efficient container handling

The performance of container terminals needs to be improved to adapt the growth of containers while maintaining sustainability. This paper provides a methodology for determining the trajectory of interacting machines that transport containers between the quayside area and the stacking area in an automated container terminal. The behaviors of the interacting machines are modeled as a combination of discrete-event dynamics and continuous-time dynamics. An event-driven receding horizon controller (RHC) is proposed for achieving energy efficient container handling. The underlying control problems are hereby formulated as a collection of small optimization problems that are solved in a receding horizon way. Simulation studies illustrate that energy consumption of container handling can indeed be reduced by the proposed methodology. Moreover, an assessment is made of performance of the proposed RHC controller under different types of uncertainties.     

Using simulation for facility design: A case study

A discrete event simulation model was developed and used to estimate the storage area required for a proposed overseas textile manufacturing facility. It was found that the simulation was able to achieve this because of its ability to both store attribute values and to show queuing levels at an individual product level. It was also found that the process of undertaking the simulation project initiated useful discussions regarding the operation of the facility. Discrete event simulation is shown to be much more than an exercise in quantitative analysis of results and an important task of the simulation project manager is to initiate a debate among decision makers regarding the assumptions of how the system operates.     

A modular simulation approach for automated material handling systems

In this paper, the authors present a modular simulation approach for the evaluation of automated material handling systems (AMHSs). The approach involves the use of high level modularity so that alternative AMHS scenarios can be evaluated using identical or nearly identical source code. The approach is implemented using the AutoMod simulation platform, and the efficacy of the strategy is demonstrated through a case study with the United States Postal Service. Results indicate that the approach is viable and that it is of value for the evaluation of AMHS scenarios in general.     

MicroPort: A general simulation platform for seaport container terminals

Seaport container terminals are essential nodes in sea cargo transportation networks. As such, the operational efficiency of container terminals in handling containers passing through them plays a critical role in a globalized world economy. Many models and algorithms have been developed to address various decision problems in container terminals to help improve operational efficiency. These decision support tools are usually used separately for specific purposes. However, the problems they are trying to tackle are often interrelated. Therefore, in this regard, an evaluation tool which can capture as many operational conditions as possible for different decision problems is necessary. This paper introduces a general simulation platform, named MicroPort, which aims to provide an integrated and flexible modeling system for evaluating the operational capability and efficiency of different designs of seaport container terminals. The software structure of MicroPort comprises three programming layers: (1) the Functions layer; (2) the Applications layer; and (3) the Extensions layer. Different layers are bound by Application Programming Interfaces (APIs). Basic functions built in the Functions layer support the Applications layer in which major operation processes can be modeled by an agent-based method. External modules and decision support tools in the Extensions layer then use APIs to adjust the system to produce suitable simulation models for specific purposes.     

集装箱起重机自动装卸系统的研究与设计

在当前集装箱运输迅猛发展的背景下,针对集装箱装卸过程中存在的时间长、效率低、劳动强度大等问题,同时为了改进集装箱装卸模式,提出了一种集装箱起重机自动装卸系统。通过解析系统功能需求,给出了系统逻辑结构。在此基础上,运用基于机器视觉的图像识别技术和双目立体视觉识别定位技术,实现货场集装箱的识别和定位,运用条形码定位技术和电机绝对编码器,实现集装箱起重机各运行机构的运动定位。计算出的吊具与集装箱的三维空间相对位置值,由工控机通过“PLC+变频器”控制起重机自动抓取集装箱,实现集装箱起重机自动装卸集装箱。应用实验结果显示,自动装卸系统集装箱单箱装卸时间较人工操作平均缩短30%,证明该系统安全适用,作业效率高,达到了集装箱装卸自动化的目标。     

Computerized materials handling and facility layout design

We are proposing a systematic approach to the design of materials handling (MH) system that includes an algorithm to select the most suitable equipment. Initially, a conveyor system is proposed while determining its association cost. To seek improvements of the system in terms of cost and equipment utilization, the possibility of supplementing or replacing the conveyor with one or more fork-lift trucks (trucks) will be investigated. The final MH system configuration will consist of conveyors and trucks so that total system optimization will be achieved. The literature on MH design is very limited and often this problem is not directly coupled with the layout problem [4]. The model proposed uses the results of a tentatively designed layout and two important characteristics of the materials, namely size and weight. Facility in this paper refers to a manufacturing plant with low to medium production volume in a process oriented environment. Facility layout and materials handling are two highly interdependent problems. The location of departments, the corresponding distances and production rates dictate the cost of MH. On the other hand, MH costs between departments, influence the departmental arrangements [10]. An iterative process is developed between the layout design and MH selection problems.     

Implementing a hybrid simulation model for a Kanban-based material handling system

Plant floor material handling is a loose loop in most assembly plants. Simulation offers a quick, controllable and tunable approach for prototyping complex material handling processes in manufacturing environments. This paper proposes a hybrid simulation approach, using both discrete event and agent-based technologies, to model complex material handling processes in an assembly line. A prototype system is implemented using a commercial multi-paradigm modeling tool. In this prototype, JIT principles are applied to both the production and the material handling processes. The system performance is evaluated and system optimization directions are suggested. The proposed hybrid modeling approach facilitates the implementation of a responsive and adaptive environment in that various “what-if” scenarios can be simulated under different simulation configurations and real-time situations.     

RISE: A general simulation interoperability middleware container

In recent years, new services on the Internet have enabled global cooperation; in particular, the Web has enabled new distributed simulation technology. Much research has been devoted to develop middleware interoperability methods on the Web. However, most existing methods have constraints in the structural rules that are placed on the design of middleware interoperability methods. For example, such constraints make it difficult to enhance interoperability via decoupling systems implementations and design, which is essential in open computing networks, as in the case of the Web. In order to achieve such objectives we present the RISE (RESTful Interoperability Simulation Environment) middleware. This all-purpose WS-based distributed simulation middleware decouples design and implementation while allowing composition scalability and dynamicity. Furthermore, it supports experiment-oriented frameworks and has the ability to put Web 2.0 services in the simulation loop. RISE is the first existing middleware to achieve such objectives, and the first to employ RESTful Web-services. We present the foundations for meeting the above objectives, and the distinct characteristics of RISE from existing Web-based approaches.     

铁路集装箱物流中心系统建模与仿真分析

铁路集装箱物流中心作业系统是复杂的随机系统,难以用数学模型准确描述。采用系统仿真的方法,依据集装箱物流中心的作业流程,构建基于eM-Plant的铁路集装箱物流中心整体作业模型。通过仿真实验,研究到站集装箱列车所载箱箱型比例、外卡到站时间间隔和内卡数量等模型参数对集装箱物流中心作业性能的影响。仿真结果表明集装箱列车所载箱箱型比例为6∶1∶3时装卸设备利用率最高,外卡在到站时间间隔超过8 min时无需等待,内卡数为5~7时辅助中转箱转运作业时间最少。     

Discrete event simulation of a proton therapy facility: A case study

Proton therapy is a type of particle therapy which utilizes a beam of protons to irradiate diseased tissue. The main difference with respect to conventional radiotherapy (X-rays, γ-rays) is the capability to target tumors with extreme precision, which makes it possible to treat deep-seated tumors and tumors affecting noble tissues as brain, eyes, etc. However, proton therapy needs high-energy cyclotrons and this requires sophisticated control-supervision schema to guarantee, further than the prescribed performance, the safety of the patients and of the operators. In this paper we present the modeling and simulation of the irradiation process of the PROSCAN facility at the Paul Scherrer Institut. This is a challenging task because of the complexity of the operation scenario, which consists of deterministic and stochastic processes resulting from the coordination-interaction among diverse entities such as distributed automatic control systems, safety protection systems, and human operators.     

集装箱码头装卸作业的调度控制模型及算法设计

对集装箱码头上装卸作业的调度控制直接影响码头的整体运营效率．本文研究了集装箱码头装卸作业的调度控制问题,提出了一个基于柔性化flow shop的集成化控制模型．该问题具有非线性规划(NP：non- polynomial)难度,因此本文开发设计了两类基于优先级规则的启发式调度算法．利用该模型来对码头中多种装卸设备进行总体调度可以提高设备之间的协调性,提高码头效率,降低成本．实验研究证明算法能有效地解决该问题．     

Analyzing a computer facility queueing problem by simulation

This paper puts forward a “C” simulation model for the analysis of queueing systems. The model is applied to a computer facility queueing problem with and without preemption. The C program was executed on a PS2 using DOS 3.30, and TURBO C-10. The program is easy to understand and implement, and can be used to simulate considerably more complicated queueing systems than the one presented.     

Haptic collision handling for simulation of transnasal surgery

Simulation of endoscopic navigation in the narrow nasal cavity poses important challenges to the computation of adequate and near‐realistic collision response and haptic feedback because extensive multidirectional contact and massive tissue deformations are inevitable. We present a virtual coupling algorithm that provides stable collision response as well as intuitive and smooth haptic interaction in all phases of the simulation. In each iteration, continuous collision detection between the point shell representing the surface of the virtual patient anatomy and the endoscope, represented by a cylinder, is performed. This allows for rolling back the instrument movement to the point in time the first collision occurred. Subsequently, a relaxation process locally optimizes the position and orientation of the instrument. A novel method of applying contact forces to colliding tissues and thus triggering appropriate deformations improves the fluency of navigation. This paper describes the algorithm and presents experimental results. © Her Majesty the Queen in Right of Canada 2012. Reproduced with the permission of the Minister of Medical Devices, National Research Council Canada.     

A simulation optimization method for internal trucks sharing assignment among multiple container terminals

Owing that the internal trucks (ITs) are frequently used as transportation equipments between yards and quaysides, the transportation efficiency of ITs secures a crucial position in container terminal productivity. Hence, a container terminal cannot contain a big number of ITs. As such, it is an imperative to explore an appropriate IT assignment strategy. Specifically for those container terminals with adjacent locations, an approach to sharing internal trucks among multiple container terminals (SIMT) is investigated. In this study, a novel strategy to resolve the SIMT problem was proposed for a specific large port with multiple adjacent container terminals. Firstly, an illustration of the SIMT strategy was presented. Then, an integer programming model for this problem is developed, where the objective functions are subject to the minimization of the total overflowed workloads and total transferring costs in every time-period among these container terminals. In particular, the rolling-horizon approach is employed for considering the immediate scheduling. Furthermore, a simulation optimization method, which integrates the genetic algorithm (GA) searching and simulation, is proposed for the near optimal solutions. Finally, the computational experiments are used to verify the effectiveness of the proposed SIMT strategy and simulation optimization method.     

Advanced concepts flight simulation facility

The cockpit environment is changing rapidly. New technology allows airborne computerised information, flight automation and data transfer with the ground. By 1995, not only will the pilot's task have changed, but also the tools for doing that task. To provide knowledge and direction for these changes, the National Aeronautics and Space Administration (NASA) and the Lockheed-Georgia Company have completed three identical Advanced Concepts Flight Simulation Facilities.

Many advanced features have been incorporated into the simulators — e g, cathode ray tube (CRT) displays of flight and systems information operated via touch-screen or voice, print-outs of clearances, cockpit traffic displays, current databases containing navigational charts, weather and flight plan information, and fuel-efficient autopilot control from take-off to touchdown. More importantly, this cockpit is a versatile test bed for studying displays, controls, procedures and crew management in a full-mission context. The facility also has an air traffic control simulation, with radio and data communications, and an outside visual scene with variable weather conditions. These provide a veridical flight environment to evaluate accurately advanced concepts in flight stations.     

A heuristic for packing boxes into a container

Given a container of known dimensions and a collection of rectangular boxes with known dimensions and number of boxes of each type, the problem is to find suitable positions for placing the boxes in the container in such a way that all the boxes can be fitted in. A heuristic for computer or manual operation is described.     

Field analysis: A mathematical method of analysis for information handling processes

A general method of analysis, mathematical in nature, is proposed for the abstract study of information handling processes. The method is based on an extension of the field concept as used in physical sciences, and makes no reference to data processing considerations. Thus, theory and practice are neatly separated so that each can progress on its own, helped but unhindered by the other. The paper details the method proposed and illustrates it with a preliminary analysis of information processing for selective mailings of periodicals. The analysis leads to a set of equations from which the values of all the derived information fields can be rigorously calculated. The discussion at the end of the paper helps to relate the present work to research relevant to the specification, documentation, design, and implementation of computer-aided information processing systems.The views expressed are those of the author and do not necessaril' represent those of the Ministry of State for Urban Affairs.Since this article was submitted, the author's name has been changed to S. H. Talbert.     

A simulation study of soft real-time scheduling and handling schemes for multimedia support

Under the control of a soft real-time framework for multimedia support, processes are scheduled by soft real-time scheduling algorithms and the timing overflows are handled by soft real-time handling methods. The paper conducts a simulation study to show the effects of the related schemes. Based on an abstract model for continuous media communications and applications, a simulator with versatile parameterization possibilities is constructed to simulate soft real-time effects concerning necessity of soft real-time, pros and cons for timing monitoring and enforcing, effects of soft real-time handling of timing-overflow, etc. Simulations driven by theoretical distributions are validated against trace-oriented simulations and the results are found to agree with each other well.