bluuebunny/crossref_metadata_2025_split huggingface dataset:
On Fly-by-Wire Control System and statistical analysis of system performance
Authors: Hammond Ronald A. , Newman David S. , Yeh Y.C. 
Published: March 2008

The flight control system proposed for future Boeing commercial airplanes is a Fly-By-Wire (FBW) system. The entirely electronic FBW system will replace the mechanical cable/quadrant/pushrod system used on earlier airplanes. The FB W system, also called an Electronic Flight Control System (EFCS), must meet extremely high standards of integrity and reliabil ity. The heart of the FBW concept is the use of redundant, dissimilar computing and communication channels. Predicting the performance of such a system is beyond the capabilities of conventional simulation and control system design methods. Moreover, the number of independent, random parameters in the system makes straight forward Monte Carlo analysis prohibitively expensive. This paper describes the simulation methods used to model the EFCS, and the use of statistically designed experiments to extract more infor mation about the performance of the EFCS with a smaller number of simulation runs than is possible with a less structured approach. The results of the analysis defined the performance of the EFCS, especially the tails of the distribu tions of the performance measures, with much greater confidence than could have been gained by more conventional methods.
A Prolog simulation for combustion control
Authors: Fogarty Terence C. 
Published: March 2008

This paper describes the simulation of the effect on overall carbon monoxide and oxygen readings of alterations to the air inlet valve of each of a number of burners sharing a common flue. Built as part of the development program of a rule-based system for combustion control in a multiple burner furnace in the steel industry it has proved to be an invaluable tool. It is now being used to aid the adaptation of the rule-based system for use on other multiple burner furnaces and on boiler plants. Every burner in the installation is represented by a number of perfect burners which in turn are represented by Prolog facts in a relational database. Changes to the burners and readings of carbon monoxide and oxygen from the common flue are accomplished by Prolog predicates operating on the database as are changes in firing level and degeneration of the burners over time. Prolog was initially chosen for ease of interfacing with the rule-based system but was found to be an ideal language for writing the simulation although elegance of expression often had to be sacrificed to brute force for it to run effi ciently on a micro computer. The output of the functional simulation of a two burner installation under the control of the rule-based system is compared with that of a two burner boiler under the control of the same system. The response of the two is shown to be similar under a broad range of operating conditions.
Simulation methodology for intermodal freight transportation terminals
Authors: Kondratowicz Ludwik J. 
Published: March 2008

This paper presents the issue of general methodology for modeling and simulation of seaport and inland terminals in intermodal freight transportation systems. The report documents a phase of the on-going more comprehensive effort aimed at developing a generalized modeling capability to provide strategic and tactical decision support for transportation logistics and intermodal terminals. By providing the object-oriented process of simula tion modeling with the coherent and uniform methodo logical basis, it was possible to construct a practical tool "TRANSNODE," The Simulator of Intermodal Transportation Terminals which allows one to model and simulate any transportation terminal, or a group of interconnected terminals, large or small, multipurpose or specialized, at optional scale. Knowledge-base and artificial intelligence concepts were incorporated in the simulator. Different from traditional simulation modeling, which combines data, knowledge and control program ming, the data-driven simulation modeling approach of the TRANSNODE system treats data and control logic as distinct parts. The resulting model is a generic simulator which can be used in many different application scenarios without requiring user simulation knowledge to modify the program. The only thing the user must do is supply the input data in the specified format through data files. Different terminal configura tions can be simulated merely by changing the input data. The developed technology is expected to be used by the industry for supporting their strategic and tactical decisions, by engineering firms in evaluating the design of their client facilities, their policies, and by the universities and research institutes in supporting and furthering their research.
BOOK REVIEW A review by Dr. Dean Uyeno, SIMULATION Book Review Editor, Faculty of Commerce, University of British Columbia, Vancouver, Canada, V6T IW8 : Getting Started with GPSS/H
Authors: Banks J. , Carson J.S. , Sy J.N. 
Published: March 2008

The Red Book lies quietly on my shelf, its cover frayed through years of heavy use, some pages torn. The book and I were both young once. Before 1974 when Tom Schriber was still pregnant with the ideas for the book, I employed a pre-publication version to equip bright and eager students with the skills to practically apply this innovative problem-solving tool, GPSS. As the years went by, however, the book and I both became grayer. Updated versions of GPSS appeared on various computer platforms. Microcomputers became the tool of choice and friendlier versions of GPSS became available. Through it all, the Red Book never changed, although its price always rose. Rumor had it that Tom Schriber wanted to revise and expand the book so we waited and remained loyal, but nothing happened. We were very patient, but now it is 1990.
ISI - An environment for the engineering use of general purpose simulation languages
Authors: Nolan Paul J. , Lane Gearóid M. , Fegan Joseph M. 
Published: March 2008

Present day approaches to discrete event simulation can be broadly classified as using either special purpose data-driven simula tion systems or general purpose simulation languages. Although the latter embrace a far wider range of applications and offer much greater flexibility in modeling for a particu lar application, their user base is restricted by the high level of expertise required. An Expert System interface to general purpose simulation languages, ISI (the Intelligent Simulation Interface), is pre sented here. Models are constructed and simulation runs are performed in an integrated environment comprising interactive menu-driven graphics, a knowledge base system and a general purpose simulation language. The features of ISI include hierarchical model construc tion, interactive experiment specification, automatic code generation, run-time animation and interactive graphical post- processing of results. An example case study is presented illustrating the main aspects of ISI. The ISI interface is shown to extend a general purpose language into an intelligent simulation environment.
Graphical programming of simulation models in an object-oriented environment
Authors: Ozden Mufit H. 
Published: March 2008

Graphical programming, which is used here to mean creation of simulation models graphically, has been used in conjunction with conventional simulation languages via block diagrams or activity networks. Its beneficial effects on model development in simulation have been generally accepted. However, none of these conventional simulation languages has reached a level of graphical programming that would impact the user's programming task substantially. Today, this is possible with the current software and hardware technology. An interactive incremental programming environment supported by a good graphical programming system that helps automatic model development, specification and verification would be greatly appreciated in modeling in general, but especially in simulation of complex real-life systems. Such a visual system could essentially be a conceptual framework for analysis of the problem at hand and become a means of communication among the people who are involved in development and management of systems. It can also be the friendly interface that forms a communication medium between the modeler and the computer for automatic programming. In this research paper, a prototype graphical programming methodology for modeling and automatic interpretation of simulation problems is developed in the object-oriented environment of the Smalltalk-80 language. The modeler uses a high-level graphical representation formalism based on the activity-cycle diagrams to define simulation models in an interactive mode. These activity-cycle diagrams can then be interpreted into the underlying program ming language and executed automatically. Thus, the modeler does not have to know the underlying Smalltalk 80 language in order to use our prototype simulation system. The future expansions to this system will include a simulation object editor, a graphical output view system and a richer high-level concept base for modeling purpose.
Space station rendezvous and berthing
Authors: Cook John , Wicks David 
Published: March 2008

This paper describes the application of johnson Space Center's Systems Engineer ing Simulator to model a complex spacecraft rendezvous and capture scenario. In this real-time scenario, an operator in one space vehicle made use of a telerobotic manipulator to capture and berth another, smaller vehicle. The goals of the study were to determine if the task could be reliably completed and to provide design and performance data on the manipulator. The study results demonstrate that it is feasible to use a telerobotic manipulator to berth an incoming Shuttle to Space Station Freedom.
Detailed simulation of a real world job shop with subassembly requirements
Authors: Townsend Miles A. , Lamb Thomas W. 
Published: March 2008

A highly-detailed model of a furniture manufacturing plant was constructed to evaluate the effects of various proposed changes and as a long term planning tool. As it turns out, this plant and model have many features of the general class of low- technology job shops with extensive subassembly: poor scheduling, bottlenecks, which are expensive to cure, and an inadequate knowledge of automation. Salient features of this study are the large size and complexity of the model and the diversity it contains. The plant seems to be typical of a low-technology job shop, and the model has the attribute of being about as realistic as can be expected of a simulation. This paper presents the results of validat ing (matching) the plant and the simulation. Extensive studies which quantify the scheduling priorities are then presented, and some new measures of performance are suggested and evaluated. Further studies on bottleneck removal and adding automation clearly indicate the costs and benefits to the plant. All of these studies would seem to be quite typical of such plants.
Investigating simulation of hardware at various levels of abstraction and timing back-annotation of dataflow descriptions
Authors: Navabi Zainalabedin , Massoumi Mehran 
Published: March 2008

Digital hardware can be described at various levels of abstraction. Functional descriptions merely capture the behavior of the circuit without revealing the details of the architec ture. On the other hand, the gate or switch level models are more robust and include great amounts of detail about the circuit (timing and architecture). Functional models are attractive because they simulate faster than low level models. However, the tradeoff is that the simulation results are not as accurate (primarily from the timing standpoint) as those obtained from low level models. Clearly, having a model that simulates as fast as the functional model and produces accuracies comparable to those of gate level models is desirable. This paper is an investigation of achieving such models. Two levels of abstractions, dataflow and gate level, are considered and the VHDL language (an industry standard) is used for describing Finite State Machine circuits at both levels. Feasibility of timing back-annotation of dataflow models with the information obtained from gate level is analyzed.
Object-Oriented Design of Output Analysis Tools for Simulation Languages
Authors: Mollamustafaoglu Levent , Gurkan Gul , Yonca Ozge A. 
Published: March 2008

Contrary to the importance given to simulation modeling, output analysis has seen little implementation effort. Most of the simulation systems and programs have very primitive forms of output analysis facilities. This might result in either statistically insignificant results, if the analyst does not have correct assumptions about the system and uses a very simple output analysis method, or it can discourage the analyst from using the methods because it will be very hard to use them without ready computer help. This paper analyzes the output analysis methods in literature and reports ways to include them in simulation environments. A generic object-oriented design for output analysis methods is also described. A critical comparison of object-oriented and traditional methods is included.
Macro Requirement Within a Simulation Interface
Authors: Munir Ahmad M. , Stam Frank A. 
Published: March 2008

The use of simulation has traditionally required a great deal of expertise. Simulation Interfaces to General Purpose Simulation Languages made simulation easier to use. However, for successfully building simulation models, modelling expertise is still required. Macros have been proposed as a tool within Simulation Interfaces which simplify the building of models. A macro in this context should be seen as a group of SimulationLanguage statements with a data interface to the user. The questions to be answered were: "What should a macro do and how should it be implemented?" The first objective of the work was to specify the macro functionality more tightly and then develop some macros. The wide range of macro applications allows categorising. An attempt was made to classify the different types of macros in a hierarchical structure. Implementation of macros in SIMAN® [1], showed difficulties such as nesting, attribute sharing, and code connectivity. To make data input for complete models less laborious, generic data interfaces were proposed. A simple model of a manufacturing cell is discussed, to show some of the above mentioned aspects. It became clear that macros could considetably speed up model building. However, bigger macros could reduce modelling flexibility to some extent.
Analysis of Envelope-to-Cycle Difference (ECD) in the Far Field
Authors: Peterson B.B. , DeWalt K.M. 
Published: March 2008

With the recent mid-continent expansion of LORAN in the United States and the worldwide increase in the use of LORAN in terrestrial and aviation applications, the understanding of propagation over land of LORAN signals has received renewed attention. This study focuses on two aspects of the ability of a LORAN receiver to select the correct zero crossing to track. First, it has long been thought that the negative change in Envelope to Dcyle Difference (ECD) s more rapid over land than seawater. Recent data has shown this not to be true and one purpose of this study is to develop a more accurate model of the variation of ECD with distance and ground conductivity. Second, with more groundwave attenuation over land than over seawater, skywave to groundwave ratios are larger and skywaves are potentially more of a problem. In our study we have developed a highly accurate model of pulses from solid state transmitters which allows the isolation of skywave from groundwave. This allows us to collect statistical data on skywave to groundwave ratio, skywave delay, and skywave ECD. These statistics, together with a knowledge of the frequency response of the receiver front end and the ECD estimation method, allow us to predict ECD bias and cycle selection problems due to skywave interference.
The Carbon Budget of the Canadian Forest Sector: Phase I
Authors: Kurz W.A. , Webb T.M. , McNamee P.J. , Apps M.J. 
Published: March 2008

An assessment of the contribution of Canadian forest ecosystems and forestry activities to the global carbon budget has been undertaken. The first phase of this study consisted of the development of a computer modeling framework and the use of pub lished information to establish the sector's current role as a net source or a net sink of atmospheric carbon. The framework includes age-dependent carbon sequestration by living forest biomass, net detrital litter fall of carbon to the forest floor, subsequent accumulation and decomposition release in three soil compartments, retention of carbon in manufactured products derived from harvested forest biomass, and burning of forest biomass for energy. There is explicit representation of the role of ecosystem disturbances, such as fire, insect-induced stand mortality, and harvesting (clear-cutting, clear- cutting and slash burning, and partial cutting), as they affect carbon releases and transfers to the forest floor and to the forest product sector. Regrowth of biomass and changes in soil decomposition processes following disturbance are also simulated within the model. In the first phase of the work, national and provin cial data bases were used to provide the first compre hensive estimates of the net carbon exchange between Canadian forest ecosystems and the atmosphere for the reference year 1986.
Simulation analysis of a Multiple Bus Shared Memory Multiprocessor
Authors: McCarron Christopher W. , Tung Cheng-Hsien 
Published: March 2008

The past several years have brought the widespread acceptance of bus based shared memory parallel computer systems. There is a great deal of research which suggests that the limitations of single bus based interconnection networks prohibit effective use of more than perhaps 16 processors. Proposals have been made for several years [7] regarding the use of multiple buses to improve overall bandwidth. In research conducted during the past two years we have studied the performance gains which could be made by providing additional buses to interconnect processors and memory. In this paper we will present the results of extensive trace driven simulation done using a sample workload. Because a detailed simulation model was created we are able to obtain fine grain detail regarding the operation of the system.
Power Plant Simulators Using Westinghouse Distributed Processing Family Hardware and Software
Authors: Griebenow Ron , Perdeus Matt , Sudduth Al , Fray Roy , Heuser Steve 
Published: March 2008

Duke Power Company and the Electric Power Research Institute have embarked on a joint effort to develop plant specific engineering and training simulators to support control replacement projects in Duke's fossil plants. These simulators use low cost personal computer hardware (PCs) and modular process simulation development software, integrated to Westinghouse Distributed Processing Family (WDPF) control hardware and software, to provide an accurate representation of the plant process and controls. Integrating the PC-based process simulation to the control system proved to be a very complex task. To meet the interface requirements, firmware was modified, and software and interface cards were developed that allow high-speed parallel access to the control system processor memory. In addition, modifications had to be made to provide necessary simulator training functions such as freezing the system, saving snap-shots, and loading initial conditions. This paper provides details on the development of the PC/ WDPF interface and simulator instructor capabilities. In addition, it outlines plans for use of the simulator as an operator training and controls engineering tool.
Modeling Of Multibody Systems For Controls Using General Purpose Simulation Languages
Authors: Zeid Ashraf A. , Overholt James L. , Beck Ronald R. 
Published: March 2008

This paper demonstrates how to use an interpretive-type simulation language, such as MATRIXx or SIMULINK, in the simulation of multibody systems. Functional blocks that contain details of the dynamics of a rigid body and of the equations of several joints were created by using the graphical user interface of MATRIXx. Models of complex multibody systems are built by graphically selecting, duplicating, and connecting appropriate blocks of rigid bodies and joints. This modularity is afforded because joints are formulated using the explicit singularly perturbed formulation. The singularly perturbed formulation, originally developed in bond graph language, is based on modeling infinitesimal defonnation in joints, a characteristic of realistic multibody joints. Bond graphs are graphical models of multi-energy doinain dynamic systems that depict and account for the power structure in the system. In this paper, block diagrams that were obtained from an algorithmic translation of joint bond graphs are coded using the simulation language graphical interface. The methodology is demonstrated by modeling the dynamic behavior of a complex multibody system; namely, a Stewart platform. Because this formulation is explicit, it sets the stage for the simulation of very large- scale multibody systems by exploiting parallelisin of novel computer architectures.
A Knowledge-Based Simulation Approach (K-SIM) for Train Operation and Planning
Authors: Sharma Ghanshyam , Asthana R.G.S. , Goel Suneeti 
Published: March 2008

This paper describes a decision support system developed to assist railroad managers in day-to-day as well as long term planning of train operation and study advantages of augmentation of infrastructure. The model simulates train movements on a railroad based on track geometry, speed restrictions, locomotives & wagon characteristics, train schedule and interaction with all other trains over a section and/or a corridor. The model helps in introducing and optimally scheduling train services. An attempt has been made in this paper to exploit potential of AI, Simulation, and operational research (OR) techniques. The user is presented with an integrated environment enabling him to easily modify, validate and implement different methods of train operation through an English-like knowledge-base, and to simulate train operations to carry out studies for different trafic mixes, track geometry, assigning blocks and temporary speed restrictions and failure conditions.
Texas-Mexico Border Intervention by Promotores for Patients With Type 2 Diabetes
Authors: Sixta Constance S. , Ostwald Sharon 
Published: March 2008

Purpose The purpose of this study is to evaluate the impact of a promotores-led diabetes self-management program by comparing the outcomes (knowledge, beliefs, and HbA1c level) of Mexican American patients with type 2 diabetes who received usual diabetic care in a wait-list control group to those who received self-management education and follow-up by promotores in consultation with clinic providers and staff. Methods This randomized control study compared the results of 63 patients who attended a promotores-led culturally sensitive diabetes self-management course at a commu- nity clinic with 68 patients in a wait-list, usual-care control group. Participants were Mexican Americans with type 2 diabetes who were patients at the clinic and at least 18 years of age. At baseline, 3 months, and 6 months, the Diabetes Knowledge Questionnaire (DKQ), Health Beliefs Questionnaire (HBQ), and HbA1c levels (drawn by the clinic laboratory) were collected. Results There was a significant improvement in the intervention group's DKQ scores over time and in treatment by time. The baseline HbA1c level was 7.49 and did not change over time in either group. The DKQ, HBQ, and HbA1c results were significantly affected by age; the DKQ and HbA1c were affected by years with diabetes. Conclusions The promotores-led diabetes self-management course improved the knowledge of patients with diabetes. Participant baseline HbA1c level was close to therapeutic level (much lower than reported in previous studies), suggesting participants received good medical care within the community clinic.