Simulation Of System Operation Research Articles

Management Science Roundup

In the first part several comments by Peter Drucker are presented. Peter Drucker said in 1958 that management science was in danger of becoming a management gadget bag of techniques for the efficiency expert. This danger existed because of the practitioners' emphasis on technique rather than on problem definition. According to Drucker, the focus of much of the work in management science has been not on such questions as what is the business enterprise, what is managing, what do the two do and what do the two need, but rather the focus has been on “Where can I apply my beautiful gimmick.” “The emphasis has been on the hammer, rather than on driving in the nail, let alone on building the house.” The regular part of the column, In this issue, presents: —“What do you think?—JB”; —“Editorial notes”; —“Inventory control for the District of Columbia—Siedman”; —“Management science at the National Bureau of Standards—Suzuki”; —“NSF seeks proposals for research conferences—Renirie”; —“Funds allocation in a corporate trust department—Chang”; —“Profit planning model for a commercial bank—Wisz”; —“Syborn's planning model—Mitchell”; —“Support for research in the mathematical sciences—JB”; —“Center for Future Research established at USC—JB”; —“Research fellowships in OR/MS at the International Center for Management Sciences, University of Louvain—JB”; —“Seen Elsewhere: (1) Technological Progress Function. A New Technique for Forecasting, (2) Forecasting Inventory Requirements in a Large Scale Department Store Setting, (3) Technical Forecasting at National Level in Japan (4) Applications of a Model Used in Calculating the Mental Load of Workers in Industry, (5) Mathematical Models for Manpower and Personnel Planning, (6) A Production Management Operating System Simulation, and (7) A Management Coach Concept for Management Development”; —“Bulletin Board: (1) TIMS meetings, (2) Other meetings/symposia, (3) Personal notes, (4) Notices and (5) Errata”; —“Deadline for future issues of INTERFACES”.

Network: System Transient Calculations by Implicit Method

Abstract The calculation of transient flows and pressures in a gas network by the characteristics pressures in a gas network by the characteristics method has a time interval restricted to the shortest pipe length divided by the isothermal wave speed. To avoid this restriction, the centered implicit-difference method is developed. It requires two equations for each pipe and one equation for each junction. The Newton-Raphson method of handling the nonlinear equations is utilized and sparse matrix algebra reduces the time of solution of the simultaneous equations. An example is presented which compares results obtained with the implicit scheme with results obtained from the characteristics method of solving for conditions at each node in turn. The new method is then applied to a simplified grid of the Consumers Power Co. and a comparison is made with field Power Co. and a comparison is made with field measurements. Introduction Steady-state analysis and design of natural gas transmission and distribution systems has progressed to a fairly sophisticated state in recent years. When time variations of parameters are added to an analysis, an entirely new independent dimension is added to the mathematical model. The analyst must be concerned with the variation of pressure with time as well as position and, additionally, must be concerned with the space and time variation of mass flow rate. From the system operator's point of view the latter modeling represents the real physical operation of a system. Some progress has physical operation of a system. Some progress has been made in this area of dynamic simulation of system operation. This paper is intended to further the knowledge of analysis and design techniques concerned with unsteady flow in natural gas systems. The primary complication in a treatment of transient-flow phenomena is in the handling of the variables in their true distributed character. The parameters of concern include frictional, inertial, parameters of concern include frictional, inertial, pressure, and gravitational forces, and system pressure, and gravitational forces, and system storage and compliance. To accomplish a solution of the partial-differential equations that relate these parameters, normally one of three different approaches is followed: an implicit procedure, an explicit procedure, or the method of characteristics. Computer programs that have been developed include PIPETRAN, developed by Electronic Associates, Inc., under contract to the American Gas Assn.; the G. E. Simulator, developed by General Electric Co.; CAP, developed at the Engineering Research Station of the Gas Council; and SATAN, developed at the London Research Station of the Gas Council. The G.E. Simulator and CAP bob use an implicit-solution procedure for the dynamic equations; PIPETRAN and SATAN use an explicit modeling. The method of characteristics has also been used successfully. The method of characteristics provides a stable, accurate solution of the equations, but has the disadvantage of costly computations for long-duration transients in a complicated system. For stability reasons the time increment in the model cannot exceed the reach length divided by the isothermal wave speed. The explicit approach is limited in the same manner; however, users of the method have successfully relaxed this restriction on the time step by using certain empirical restraints to achieve stability. The implicit finite-difference representation of the equations offers the advantage of guaranteed stability for a large time step, but has the disadvantage of requiring the solution of a set of nonlinear simultaneous equations at each time step. For a complicated gas network, the matrix becomes quite large, the computer storage requirements become very large, and the solution time again becomes excessive. SPEJ P. 356

Multimedia And Other Advanced TrainingTechniques

Individualization of training has resulted in designing specific advanced training techniques such as simulators and multimedia telematics. Simulator: Training for crane and gantry crane drivers by simulators has increased considerably the level of competence at a lower cost than traditional the spot training in a shorter period with a better level of safety. Telemactics multimedia European project Safety-net The Port of Le Havre and IPER are the French representatives amongst 13 partners from 7 countries in the European project SAFETY-NET. The 4 industrial sectors involved are : MARITIME, PORT, offshore oil exploration and rail. The project aims at demonstrating the feasibility of training on the work place by telematics. Each Competent Development Module (CDM) has three components : a training component, a knowledge assessment and a performance assessment. The technology for distance learning includes CDROM, INTERNET, VISIO CONFERENCE. An appraisal shows a potential of 3500 learners located on 30 European competence development sites. Extending the network world-wide is expected through satellite broadcast. 1 Tomorrow's technology already available for today's training Training gantry crane drivers by SIMULATOR Distance learning by INTERNET Transactions on the Built Environment vol 36, © 1998 WIT Press, www.witpress.com, ISSN 1743-3509 J4 ivianume engineering ana rons Le Havre Port Authority Engineering Department is involved in maritime public works and assistance abroad, therefore it provides the following-up training. Port training is organised by IPER either in Le Havre or in-company in foreign countries. Short courses aim at training port managers and higher executives. The seminars are conducted both in French and English. Additionally a Master Degree on international transport and logistics is offered to students over one year. Efficiency in training has always been a genuine target keeping abreast with cost reduction. Organising small group sessions on a specific content was the first step in meeting the needs of port human resources. Experience has led to go further into individualisation and has resulted in designing specific advanced training techniques such as simulators and multimedia telematics. 1.1 Training sessions on a simulation system for gantry crane operators In order to train container gantry crane operators or to improve their driving these machines, the Port of Le Havre Authority has equipped with a simulation system of operation of gantry cranes. With this kind of equipment, the Port of Le Havre Authority can train its own staff but it can also organise training sessions intended for the staff of other French or foreign Port Authority. 1.1.1 The training equipment The simulation system is made up of a series of equipment grouped together in the premises of the Training Centre of the Port of Le Havre Authority. A first room shelters a driving cab, raised on hydraulic jacks, which places the operator in driving conditions, the video projection and the electric and hydraulic equipment simulating the movements. The physical environment of the cab is that of a real driving cab of one of the latest gantry cranes. A second room shelters all the driving and monitoring equipment of the simulation system.