Ebrahim Shayan

Investigation of port capacity under a new approach by computer simulation

This paper investigates the role of computer simulation in evaluating the performance of a container terminal in relation to its handling techniques and their impact on the capacity of terminal. The paper investigates and compares two different operational systems (current and proposed) statistically via a simulation model. The paper also addresses issues such as the performance criteria and the model parameters to propose an operational method that reduces port terminal congestion and increases the capacity of terminal.

The importance of information technology in port terminal operations

Information technology has become an essential part of the rapid and accurate transfer and processing of enormous volumes of data processed in international transport firms and port organisations. The proper management of systems, which process this information and communicate it to those who manage port operations, is vital for efficient transport. This explains why container‐tracking systems are given high priority among operational computer applications in ports. Investigates the importance of information technology and its role in improving the operational systems in cargo handling. A computer simulation model is developed to compare two different operational systems – a container terminal equipped with electronic devices versus a terminal without such devices. The importance of information technology in supply‐chain management is also discussed.

Genetic algorithm for facilities layout problems based on slicing tree structure

The use of genetic algorithms to solve facility layout problems has gained popularity in recent years among researchers. A difficult requirement for the use of genetic algorithms in layout problems is an efficient method of coding the relevant features of a layout as a chromosome. The slicing tree structure has gained popularity in developing genetic algorithms for layout problems. However, previous implementations based on slicing tree structure mostly require repairing procedures to ensure that the chromosomes represent legal layouts after application of genetic operators. Some representations do not permit an exhaustive search. This paper reports on design, development and experimentation results of a new genetic algorithm named (GA.FLP.STS), which always produces legal chromosomes without any need for repairing procedures. A penalty system was introduced to facilitate generating facilities with acceptable dimensions. (GA.STS.FLP) required insignificant processing times even for test problems of 100 facilities solved.

A fuzzy logic modelling of dynamic scheduling in FMS

This paper is concerned with scheduling in flexible manufacturing systems (FMSs) using a fuzzy logic (FL) approach. Four fuzzy input variables: machine allocated processing time, machine priority, due date priority and setup time priority are defined. The job priority is the output fuzzy variable, showing the priority status of a job to be selected for next operation on a machine. The model will first select the machines and then assign operations based on a multi-criteria scheduling scheme. The performance of the approach is compared against established methods reported in the literature. The performance measures considered average machine utilisation, meeting due dates, setup times, work in process and mean flow times. The test results demonstrate the superiority of the fuzzy logic approach in most performance measures.

Cost estimation in flat plate processing using fuzzy sets

Cost estimation in Flat Plate Processes (FPPs) involves a combination of man, machine and resources and consequently, a combination of physical processes, engineering resources and economic laws as well as actions and behaviour of people should be taken into consideration. Thus, in cost estimation process, apart from physical and engineering variables, there often exist several subjective criteria, which need to be described qualitatively and linguistically. In addition, there are some probabilistic or random variables including labour fatigue, shortage of resources and materials, failure of machines, unavailability of facilities and so on, which can not be accurately predicted. Using analytical and mathematical approaches, it is not possible to quantify and transform these imprecise and subjective criteria and random factors into proper input variable in the cost estimation model. Therefore, the state of uncertainty should be considered in cost estimation problem in some ways. In this paper, fuzzy sets and probability distribution approaches are applied to tackle the problem of uncertainty in cost estimation in order to generate reliable cost estimates in flat plate processing industry.

POSITIVE IMPACT OF DISTRIBUTION CENTRES ON THE ENVIRONMENT

The transport sector in general, and trucks in particular, generates a significant amount of emissions in Australia. It appears the trend will escalate unless different measures are taken to reduce the reliance of freight transport on trucks. This paper discusses the benefits of distribution centres as a means to reduce road congestion, increase safety, protect the environment by reducing atmospheric pollution and improve freight distribution. It also provides the effective use of the existing rail network and its infrastructure and improves the lead-time as well as lowering the cost of transportation of cargo. It also investigates the positive impact of distribution centres located near to manufacturing and farming production units. A simulation model has been developed and used to help determine the amount of atmospheric pollution produced by two modes of land transport, rail and road, for the movement of containers between port and destination. Results derived from the model provide evidence about a preferred land-transport regime. The paper has two sections: (1) the role of distribution centres in the chain of transport and (2) the impact of distribution centres on the environment. The first section investigates the feasibility of the implementation of distribution centres in the State of Victoria with respect to rail line capacity and location allocation. The second section presents an additional simulation model that investigates the role of a distribution centre in relation to the amount of atmospheric pollution produced by rail and road, while containers are carried between port and destination.

Modelling of a continuous food pressing process by dimensional analysis

This paper focuses on the development of a mathematical model of a continuous pressing operation where biscuit shape is formed. It identifies a functional relationship and predicts its parameter values using a set of observed data. Dimensional analysis was used to model biscuit thickness as a non-linear function of a number of predictor variables and multiple regression was applied for parameter estimation of the model. The results were satisfactorily tested against real data.

Tool management in flexible manufacturing systems

Describes a systematic way to design and develop a generic relational model for a tool management system in FMS. Reviews the need for tool database management in FMS and discusses the advantages. Highlights the requirements for a successful tool database and presents a systematic way to design and develop a relational tool database. The developed tool database is implemented by using the ORACLE database management system. Finally, presents four demonstration runs.

Cost/time estimation in flat plate processing using fuzzy modeling

Cost/time estimation in flat plate processing (FPP) is a complex system of man-work-environment-organization. As the share and impact of physical, psychological, personal, and other characteristics of human in this complex system becomes bigger, the state of FPP time estimation changes from well defined to ill-defined (uncertain). Due to so many inter-related, imprecise, and ill-defined factors involved in activity time, it is too complicated; time consuming and expensive to model these factors into a universally accepted activity time/cost estimation system using mathematical or even analytical-experimental approaches. This paper addresses the issue of uncertainty treatment in activity time estimation in FPP. The emphasis is placed on modeling of nonrandom uncertainties using fuzzy sets.

Modelling petroleum fields with movable platforms

Abstract Mathematical programming models for an early evaluation of a petroleum field have previously been developed. Among these is a mixed integer programming model that incorporates a reservoir simulation and an economic evaluation model. This model is formulated to answer questions related to where wells should be drilled when the goal is to get the best total value from the field development. Motivated by the new technology in flexible platform systems, we have developed an extension of this model. In many cases it is desirable to determine the value of the possibility of moving a production platform. We discuss a model that finds when, if at all, the platform should be moved to another location on the field. We also present some experimental results illustrating the value of this feature.