bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of a flexible arm robot for space station applications
Authors: Janssen Paul J. , Harrand Vincent J. , Wessling Francis C. , Choudry Amar
Published: March 2008

A Flexible Arm Robot (FAR), which could be attached to the Space Station, could be used for reaching many locations in the vicinity of the Space Station without the need for astronauts in space suits to perform extravehicu lar activity. FAR is a tube-shaped robot consisting of many stacked segments which are individually controllable. Each segment has six degrees of freedom. Because this robot has many degrees of freedom, new algorithms were needed to control it.

A graphical model and a mathe matical model (direct and inverse kinematics) of FAR have been developed. Based on these two models, a software package for simulating this Flexible Arm Robot on a computer system has been made. FAR and the two models are briefly described in this paper.
A pilot study of the impact of animation on decision-making
Authors: Henz Luehrmann Monica A. , Byrkett Donald L.
Published: March 2008

Recent years have seen the intro duction and growth of graphical animation in simulation. Animation is frequently extolled for its use as a debugging aid, as a communication aid, and as a decision aid. This paper reports on a pilot study that was undertaken to measure the impact of animation as a decision aid. Two versions of a simulation model of a flexible manufacturing system were developed; one with animation and one without.

Subjects were given a problem scenario involving a design decision concerning the flexible manufactur ing system. Half were given the animated simulation model as a tool to assist in the design decision and half were given the nonanimated simulation model. The assignment of subjects to type of simulation model was made randomly. The results of the experiment are presented in terms of five variables: decision quality, decision speed, task performance, problem comprehen sion, and viewer preference. Based on this pilot study, suggestions are made for improving the experimen tal design of future studies.
A real-time distributed simulation of PBX with software reuse
Authors: Chang Carl K. , Chang Young-Fu , Aoyama Mikio
Published: March 2008

Rapid prototyping has proven to be a promising way of accomplish ing a feasibility study. It cuts costs and reduces the complexity of the development of real-time distributed systems. UICPBX is a simulator of Private Branch eXchange (PBX), an important member in the family of telephone switching systems. It has been prototyped using the C language in a SUN workstation environment under UNIX.

During the development of UICPBX, techniques of software reusability have been applied. First, a software hierarchy with three layers (kernel, basic supp orting and calling functions) is employed according to the functional charac teristics of the application system. Secondly, a software library is established to provide an effective environment to support reuse of functions developed at the middle (basic supporting) layer of the software hierarchy. The powerful high-resolution, bit-mapped graphic screen of SUN workstations facilitates effective process monitor ing and visualization of multiple real-time tasks.
On Monte Carlo simulations of dynamic systems
Authors: Bouton Peter M. , Fai Ma
Published: March 2008

The Monte Carlo method provides both design and research engineers with a useful tool for evaluating the effect of input uncertainty on system performance. This paper addresses the basics and the utility of the Monte Carlo approach. Two practical applications of the method help to demonstrate why Monte Carlo simulation is becoming a contemporary trend in system analysis.
Integrated intelligent simulation environment
Authors: Ming Rao  , Jiang Tsung-Shann , Tsai Jeffrey J.-P.
Published: March 2008

In this article, we describe a new simulation method for engineer ing applications. The architec ture development is one of the most important techniques among the AI research tasks. An integrated intelligent simulation system is a large knowledge integration environment that consists of both symbolic reasoning systems (expert systems) and numerical compu tation packages. These software programs are controlled by a meta-system, which manages the selection, operation and commu nication of these programs. This new architecture can serve as a universal configuration to develop the fifth generation simulation environment for many complicated applications.
A rule-based simulator for modeling Just-in-Time manufacturing systems (JITSAI)
Authors: Manivannan S. , Pegden C. Dennis
Published: March 2008

The design details of a new rule-oriented simulator for modeling the production related issues in a Just-in-time (JIT) system are discussed in this paper. The user interacts with the simulator and provides input data related to a JIT system and the simulation experiment. The simulation model is generated automatically by the computer using the rules selected from a domain-specific rulebase. The machine utilization, system throughput, number and type of kanbans, and average WIP levels are some of the results generated by the simula tor. The design was originally implemented using LISP on an IBM 4381 computer and subsequently extended to Macintosh and Sun workstations.
Development of a state space boiler model for process optimization
Authors: Dieck-Assad G.
Published: March 2008

A physically based boiler model is developed to solve a set of optimization problems. The model evaluates the normal operation of a 235 MW gas/oil boiler. The model has 7 states in the process and 25 states in the control system. The boiler has a two stage superheater, a single stage reheater and an economizer. The designed steam pressure is 1815 psia with both superheat and reheat temperatures of 1000 deg F. The model is used to solve the optimal set-point scheduling problem in the boiler system. This paper discusses the boiler process state space model.
Simulation of white noise in dynamical systems
Authors: Pachter M. , Briggs M.M.
Published: March 2008

We address the problem of how to properly handle the application of white Gaussian process noise to a digital simulation of a continuous-time linear dynamical system, given the standard device of a Gaussian random numbers generator.
An expert simulator for allocating the quality assurance effort in software development
Authors: Abdel-Hamid Tarek K. , Leidy Frank H.
Published: March 2008

Increasingly software quality assurance (QA) is being recognized as a critical factor in the successful development of software systems. However, because the utilization of QA tools and techniques adds significantly to the cost of developing software, the cost-effectiveness of QA has been a significant concern to the software quality manager. As of yet this concern has not been adequately addressed in the literature.The objective of this research effort is to develop an expert/simulator to support the QA effort allocation decision. The expert system module derives QA effort allocation schemes, feeds them into the simulation model for testing, and uses the feedback from the simulation results to improve upon the efficiency of the QA effort distribution.In a case study involv ing a NASA software project, the model accurately replicated the project's dynamic behavior. The expertlsimulator was then capable of deriving a more cost effective QA policy that achieved a 26% reduction in total project cost.
Optimal dynamic scheduling of a power generation system to satisfy multiple criteria
Authors: Forouzbakhsh Farshid , Deiters Robert M. , Kermanshahi Bahman S.
Published: March 2008

A computer algorithm for the optimal scheduling of generators in a power system is presented and tested. The algorithm, based on goal programming, automatically and dynami cally schedules the output of each generator in the system for optimal operation. The optimal operation can take into consideration multiple objectives such as economy, security, and reduction of pollution as well as practical constraints.

To validate and test the algorithm, an example system of 5 generators, 10 busses, and 11 transmission lines is optimized for two objec tives: minimal generation cost and minimal emission of nitrous oxides (NOx). Hourly changes in total power demand in the range of 90% to 110% are considered together with a constraint of maximum permissible total NOx emission. Other practical equality and inequality constraints are incorporated into the optimiza tion algorithm.

The simulation results demonstrate that the outputs of the generators can be changed smoothly and dynamically. Furthermore, using the algorithm, computer control is practicable either by direct on-line optimization or by using the feasible operation region generated as a small data-base by off-line computation.
Desktop simulation: Modeling for managers
Authors: Rathburn Thomas A. , Weinroth G. Jay
Published: March 2008

This article discusses the potential of merging expert sytems and simulation to provide a platform for sensitivity analysis by managers. The authors have developed a desktop simulation, a generalized simulation for a class of problem. Creating an interface with an expert system shell, the authors used a front-end to allow for customization of the generalized model to the current parameters. The front-end edits the simula tion code; the user may then run the simulation. This iterative approach allows for rapid consideration of a number of prototypes based on various parametes of interest.
Simultation Network News
Authors: Fishwick Paul
Published: March 2008

This column focuses on a single topic within the field of computer simulation. All the material comes directly from the electronic news group (bulletin board) called Simulation Digest. The Digest can be obtained over INTERNET by accessing the news group 'comp.simulation' or by sending e-mail to: 'simulation-request@bikini.cis.ufledu'
Simulation Network News
Authors: Fishwick Paul
Published: March 2008

This column focuses on a single topic within the field of computer simulation. All the material comes directly from the electronic news group (bulletin board) called Simulation Digest. The Digest can be obtained over INTERNET by accessing the news group 'comp.simulation' or by sending e-mail to: 'simulation-request@bikini.cis.ufl.edu'
OMEGA: A reconfigurable transputer-based digital simulator
Authors: Morse Michael J. , Forsythe William
Published: March 2008

This paper describes a high performance digital simulator which is novel both in its design and its implementation. The basic simulator comprises 32 identical processing elements (PEs) interconnected through a global switch in a non-blocking arrange ment; each PE is a transputer and support circuitry configured in an unusual way. The processors operate with floating point arithmetic to avoid the problems of scaling, and a frame time of 0.1 msec., irrespective of problem size or complexity. The performance of the simulator has been validated using PEs to realize both linear and non-linear functions in a variety of simulations.
Simulating management's earnings-per-share forecasts
Authors: Cameron Alex B.
Published: March 2008

This study attempts to simulate management's earnings per-share forecasts using six naive time series models. The results indicate two (random walk and random walk with a drift) of the six models were significantly more accurate than the other four models in simulating management's earnings forecast. Both exhibited a tendency to consistently underforecast earnings, and it was hypoth esized that this could be due to an inherent bias in the data.

The results for the remainingfour models were not as favorable. The two submartingales and the simple linear trend models exhibited a high degree of variability in accuracy and significant biases based on the magnitude of the forecast. The arithmetic average model appeared to be unbiased but exhibited a high degree of variability. The results of the study indicate that it may be possible to simulate management's earnings forecasts using relatively naive mathemati cal models.
Development of design guidelines for local area CSMA/CD networks
Authors: Cobb Richard , Mansfield Edward R. , Mellichamp Joseph M.
Published: March 2008

A local area communications network is complex with many interdependent variables which influence system perfor mance. The purpose of this research was to develop simplified design guidelines that can be used by local area communications network designers. These guidelines apply to situations where designers are consider ing the CSMA/CD contention access protocol. A simulation model applied to this type environment can aid in design by helping to define the range of efficient system operation during the preliminary network configuration design and evalua tion. The research includes the development of a GPSS simulation model that is used to analyze the effects of network design variables. These variables are considered in an experimental design that inputs simula tion results to a multiple regression analysis. The resulting regression equation offers network designers a simplified tool useful in estimating message transmission delay. This will provide an easy method for network perfonnance evaluatiort during the initial network design phase when sophisti cated simulation or analytical modeling techniques are not applicable or not appro priate to the design environment.
Monte Carlo simulation on microcomputers
Authors: Uyeno Dean
Published: March 2008

Monte Carlo analysis is a practical tech nique for including the effects of uncertainty in a model intended for decision support. It has been infrequently used, however, perhaps because it has been tedious and boring to do. A recently available software add-in to 1-2-3 named @Risk makes Monte Carlo analysis much easier. This paper demonstrates Monte Carlo analysis in spreadsheet simulation in 1-2-3 so that you are better able to judge whether or not you should employ it.
Induction of decision making rules for context sensitive systems
Authors: Clymer John R. , Cheng David J. , Hernandez Daniel
Published: March 2008

System design and analysis of highly context-setrsitive systems is both a difficult and time consuming problem. An induction program is discussed that greatly mitigates this problem. The Operational Evaluation Modeling (Op EM) Induction program receives, as input, a case file generated by an OpEM discrete event simulation program. Each case consists of a decision fact plus all knowledge base facts available for this decision (i.e., the decision context). The OpEM induction program analyzes this set of cases and produces an optimal set of rules that decides all of these cases correctly. An OpEM directed graph model is presented that describes the complex, context-sensitive parallel processes of a single-track railroad system, and a Pascal simulation of this railroad system is described to demonstrate that effective decision rules can be induced from extracted expert knowiedge obtained from simulation generated cases. A description of the OpEM induction program is provided, and rules generated by it are compared with rules generated by Ross Quinlan's ID3 Induction prograin using the saine set of cases.
Simulation of Main Memory Database Recovery
Authors: Le Gruenwald  , Eich Margaret H.
Published: March 2008

In a main memory database (MMDB), the primary copy of the database may reside permanently in a volatile memory. When a system failure occurs, the database must be reloaded efficiently from archive memory into main memory. This paper presents four different reload schemes and the simulation models constructed to compare the algorithms. Simulation results indicate that the reload scheme based on freguency of data access gives the best overall performance in terms of transaction response time and system throughput.
Chaos and Fractal Algorithms Applied to Signal Processing and Analysis
Authors: Handley J.W. , Jaenisch H.M. , Bjork C.A. , Richardson L.T. , Carruth R.T.
Published: March 2008

Modern signal processing methods strive to maximize signal to noise ratios, even in the presence of severe noise. Frequently, real world data is degraded by under sampling of intrinsic periodicities, or by sampling with unevenly spaced intervals. This results in dropout or missing data, and such data sets are particularly difficult to process using conventional methods. In many cases, one must still extract as much information as possible from a given data set, although the available discrete data is sparse or very noisy. In such cases, we have found the algorithms derived from Chaos and fractal theory to represent a viable alternative to traditional spectral analysis. The data analysis techniques discussed in this work include phase space reconstruction, Poincare sections, radius of gyration exponent, artificial insymmetration patterns (AIP), Liapunov spectra, correlation techniques, R/S analysis, K-factor, fractal statistics, maximum entropy method, and wavelets.
Simulating Microprocessor-Based Parallel Computers Using Processor Libraries
Authors: George Alan D.
Published: March 2008

As the limits of sequential processing are being approached, the use of parallel architectures in the implementation of modern scientific computer systems grows in importance. The use of advanced and powerful microprocessors in these systems is a particularly effective approach. However, the costs associated with such systems make it critical to be able to forecast system behavior before an actual hardware proto type is constructed, in terms of such requirements as real-time performance, throughput, bandwidth, latency, reliability, availability, etc. Experience with the design and simulation of a new parallel computer is used as an example to illustrate a technique by which requirements can be accurately analyzed without the risk of premature hardware implementution. Using processor libraries, the complexities of the actual system are portrayed in the form of a software-based prototype system which provides significantly more accuracy than traditional simulation methods.
SCS Industry Technology Award Presented at Duke-EPRI Mobile Simulator Dedication Ceremony
Authors: Sharon Ariel
Published: March 2008

On The Road To Excellence: Operating excellence is essential if utilities are to successfully meet the challenge of an increasingly competitive future. Operators must have the knowledge and skills to operate plants with perfection. Replica simulators have been used to train nuclear power plant operators for over 15 years. However, high cost and lack of flexibility have limited the use of simulators by the fossil generation industry.

The Duke-EPRI Mobile Simulator represents a breakthrough in cost and flexibility which makes near-replica simulators affordable, compact and mobile. Duke Power Company, the Electric Power Research Institute, TRAX Corporation, and Westinghouse Electric Corporation teamed to produce a trailer-mounted simulator that includes a complete Westinghouse control system "simulated" by a process model developed by TRAX Corporation. The simulator can be loaded with different control systems and process models to provide near-replica training at various plants.

Duke power will use the mobile simulator to provide operator training and controls engineering for all of its fossil plants, yielding estimated benefits of over $175 million during the next 15 years. The benefits will be realized in the areas of reduced operator preventable trips, reduced commissioning time for control system replacements, quicker start ups, and improved maneuvering capability.
Two-Level Cache Performance for Multiprocessors
Authors: Zimmerman Stanley L. , Robinson J.P.
Published: March 2008

For shared bus multiprocessors operated in multiprogramming mode, the addition of second-level caches tends to significantly increase system performance. Trace-driven simulation was employed to obtain performance measurements over a range of system parameters, with the cache sizes at both levels being the parameters of most interest. For both light and heavy system loading, the addition of second-level caches was found to boost system performance. For heavily loaded multiprocessor cases, the workload-averaged percentage increases in performance ranged from 187% with 32k byte first-level caches to 507% with 4k byte first-level caches when 128k byte second- level caches were added. The main memory configuration and number of processors largely dictates the performance of a shared bus multiprocessor running in multiprogramming mode. The addition of larger second-level caches to the system results in increased system performance over a range of system configurations and workloads.
A Portable Process-Oriented Compiler For Event Driven Simulation
Authors: Harrington Brian E. , Fishwick Paul A.
Published: March 2008

Modern Simulation Program Generators (SPGs) must address four key issues: portability, user interface, consistency and extensibility. Portable SPGs allow the user to edit the model outside of the SPG giving the user the flexibility to add features not supported by the SPG. An SPG's user interface should mimic the user's perception of the system to be modelled. Often the user visualizes the model as a network diagram. The user interface and the SPG's consistency deter mine ease-of-use. SPGs should be developed under a standard environment to provide consistency between programs. They should be modular, to allow the code generator to be modified as new simulation tools are developed. Xsimcode addresses each of these issues. It is a portable SPG, providing flexibitity for experienced modelers. It uses a graphical, direct manipulation interface to represent the simulation model. A noun-verb dialogue limits the user's choices once an object is selected. As an X-Windows program, Xsimcode's interface is consistent with many other X-Windows programs. Xsimcode's user interface module and code generation module are separated by a data structure, allowing Xsimcode to be extended to support other simulation languages or ported to other windowing environments.
Parallel and Vector Logic and Fault Simulation Algorithms on the Cray Y-MP Supercomputer
Authors: Bataineh Abdulla , Özgüner Füsun , Szauter Imre
Published: March 2008

In this paper, we present parallel algorithms for logic and fault simulation, developed for and implemented on the Cray Y-MP supercomputer, a general purpose shared- memory parallel machine with vector processors. The parallel-and-vector version of the event-driven logic simulation algorithm achieves a speedup of 52 on the Cray Y-MP with 8 processors, with a maximum performance of about 2 million events per second. These results are comparable to the performance of hardware simulation engines and can be implemented on other parallel machines without major modifications. The second algorithm is a parallel and vector version of the parallel fault simulation algorithm. Experimental results on benchmark circuits [1] show that very high evaluation rates (20 to 32×109 evaluations/s.) can be achieved. Speedup factors of 45 to 69 are observed between the scalar and the parallel and vector execution of the fault simulator.
Petri Net Based Methodology for Task Scheduling on Multiprocessor Architectures
Authors: Gourgand Jeanne-Marie , Norre Sylvie
Published: March 2008

This paper proposes a Petri Net based methodology for task scheduling on multiproces sor architectures. The aim is to build automati cally a stochastic model (markovian model or stochastic simulation model) for both perfor mance evaluation and task scheduling. The modelling process that we use consists in the consecutive elaboration of two models: the knowledge model and the action model. The knowledge model is a formalization of the structure and the working of the system, using Petri Nets. This knowledge model is made of three parts: a logical subsystem (precedence constraints between tasks), a physical subsystem (multiprocessor architecture) and a decision subsystem (scheduling method). The action model is a translation of the previous knowledge model in a programming language or in a mathematical formalism. We propose in this paper two kinds of action models: a stochastic simulation model and a markovian model. These models are dedicated to dynamic task allocation between identical processors without communi cation cost between tasks. It is to be remarked that these action models are automatically deduced from the corresponding knowledge models. Finally, we report some results obtained from these two action models. In particular, we highlight that these two independent models return identical results and so validate them selves.
A Simulation Methodology for RISC Computer Systems
Authors: Obaidat M.S.
Published: March 2008

This paper presents a simulation methodology for evaluating the performance of single and multiprocessor Reduced Instruction Set computers, RISC. The uniprocessor RISC model considers all interactions among various units in the CPU for a wide spectrum of application programs and conditions. The instruction flow of each instruction is modeled and data dependencies and stalls in the different pipelines are considered and treated. The single processor detailed model is used in the Crossbar and Delta-based multiprocessor models. Benchmark programs are characterized by their Input/Output ratio (α). A comparative simulation performance study of crossbar switch and Delta-based multiprocessors using RISC processors is made. The MC88100 RISC processor is considered as a case study for both cases. Different simulation experiments have been carried out to predict the behavior of the single and multiprocessor systems if certain parameters or conditions are varied or satisfied.
Simulation of a Fuzzy-Logic Control System
Authors: Kom Granino A.
Published: March 2008

We review fuzzy-control principles and show a simulation program permitting convenien t generation of membership functions and simple output interpolation. Interactive simulation is more than ordinarily important for economical fuzzy- controller design, which must reduce the number of membership classes and input/ output rules as much as possible. We use a personal computer and interactive editing to compare linear and fuzzy servo controllers. With 50 per cent class-membership overlap ("pseudo dither"), our fuzzy logic produces linear interpolation, and thus completely unimpaired servo performance even if we use only 2 fuzzy sets ("positive" and negative") each for error and output rate.
Coordinate Transformations in Distributed Interactive Simulation (DIS)
Authors: Lin Kuo-Chi , Ng Huat
Published: March 2008

The newly drafted Military Standard on Distributed Interactive Simulation (DIS) uses the geocentric coordinates as the world coordinates. However, SIMNET and most of the existing simulators use local topocentric or geodetic coordinates as their world coordinates. This paper establishes the coordinate transformations among the different coordinate systems. The orientation representations in different coordinates are also disccessed.
Use of Colour to Describe System States in a Process Simulation Language
Authors: Morris A.S.
Published: March 2008

The paper describes an extension to a standard, block-structured, interactive simulation language in which colours are used to indicate the levels of variables in the simulated process. A coding system is used to classify the level of simulated process variables into three regions of safe, unsafe and dangerous operation, represented by green, yellow and red colours respectively. The enhanced simulation package facilitates controller development for industrial plant and avoids dangerous levels being overlooked in the simulation of prototype systems prior to their implementation on plant. The use of the enhanced facility is demonstrated by the simulation of the electrode drive system and controller for an electric arc furnace.
Knowledge Based Simulation Systems - A Review
Authors: Merkuryeva Galina V. , Merkuryev Yury A.
Published: March 2008

The paper presents a review in the field of knowledge based simulation systems (KBSS). Development and application of such systems allow the user to perform simulation studies without special training in programming languages, simulation theory, and other skills related to simulation project realization. KBSS architecture, programming paradigms and development tools are considered. Problem areas and characteristics of the main applications of KBSS are described. More than 50 examples of research and commercial systems are given in the tables.

Quality assurance techniques which may be used in KBSS are considered. They support tools for model reduction and parallel processing techniques. The perspectives for KBSS development are discussed. Among them are support of both on-line digital control, simulation modelling and data base management, development of parallel and distributed systems, fuzzy simulation environment development, combination of the expert system capabilities with potential for adaptation by artificial neural nets. Bibliography includes 168 references.
A Simulation Study of DQDB Metropolitan Area Network
Authors: Catania V. , La Corte A. , Puliafito A. , Vita L.
Published: March 2008

In this paper we focus on a simulation analysis of the performance of the DQDB access protocol with both multiple priority levels and Bandwidth Balancing Mechanism (BBM) activated. The analysis presented is oriented towards the evolution of the effect the BBM has on access delay and bandwidth sharing assuming different types of workload.
FACTOR/AIM: A Manufacturing Simulation System
Authors: Lilegdon William R. , Martin David L. , Pritsker A. Alan B.
Published: March 2008

This paper presents a formal description of FACTOR/AIM™, a complete manufacturing simulation system. AIM contains a manufacturing modelling language, a simulation analysis program, a problem definition interface and a database for storing inputs, models, animations, simulation outputs and analysis procedures. These components of AIM are integrated in a seamless manner to facilitate both their concurrent and batch execution. AIM also provides utility programs for importing and exporting data to the AIM data base. The focus of the article is to provide a basic understanding of a manufacturing simulation system.
Composite Dispatching Rules for Multiple-Vehicle AGV Systems
Authors: Lee Jim
Published: March 2008

The objective of this research is to evaluate the performance of three composite AGV dispatching rules which can be easily implemented in manufacturing or assembly systems. Attempts were also made to compare the composite rules to a simple dispatching rule and to identify system operating parameters which might affect the performance difference of the rules. Composite dispatching rules tested in this study are based on combinations of concepts proposed in previous research. Discrete event simulation models were developed to implement the heuristic rules in a hypothetical assembly system with a zone control scheme to avoid vehicle collision. The simulation result revealed that a combination of the Nearest Station and the Stay-in-the-same-station (NS-SS) rule outperformed the other rules. Statistical analyses on the simulation output suggest that a composite rule which minimizes the AGV travel distance might be a good control strategy, and the operational factors which affect the performance difference are dependent on the type of dispatching rules.
Functional Simulation Using Spreadsheets
Authors: El-Hajj Ali
Published: March 2008

In this paper, a functional simulation method using modern spreadsheet programs is dis cussed and evaluated. This method is based on simulating the basic blocks that constitute a system and in connecting these blocks together using a graphical interface. The simulation can be customized using toolbars, menus, help and dialog sheets. It is characterized by its low cost, flexibility, and simplicity.
Efficient Numerical Integration Using Gaussian Quadrature
Authors: Place J. , Stach J.
Published: March 2008

Simulation engineers are occasionally required to include numerical integration in their simulation models. The technique most often used is the simple "trapezoid method." In this short tutorial, we review Gaussian Quadrature techniques for nu merical integration and show how careful deployment of coefficient weights and se lection of the number of coefficients can dramatically reduce the work required to produce excellent numerical results.
Object-Oriented Simulator Design For an Automated High-Speed Modular Placement Machine Family
Authors: Csaszar Peter , Tirpak Thomas M. , Nelson Peter C.
Published: March 2008

This paper introduces the computer model established for a new family of modular type, multi-station walking beam high-speed chip mounter (also called chip shooter) machines, and the implemented high-accuracy simula tion software. The objective of the project was the de velopment of a comprehensive simulation tool that can replace the real machines in experiments regarding sys tem analysis and setup, yet provide accurate cycle time estimation. The thorough analysis of the machines led to the understanding of the characteristics of each part of the system, as well as the hierarchy of the parts and the interaction between them. This well-defined hierar chy and separability of different parts suggest the ob ject-oriented paradigm for the implementation of the simulation software. This paper highlights the major goals successfully addressed by the developed software: the identification of the system hierarchy with its rep resentation in a C++ class structure, the implementa tion providing code efficiency, and the design of I/O features that prepare the simulator to be embedded in an optimization procedure.
A Study of Wool's Tensile Strength in Early Stage Processing
Authors: Lijing Wang  , Xungai Wang
Published: March 2008

The tensile strength of wool during pre-spinning processing is examined in this paper. Both single fiber breaking load and fiber bundle strength are studied. The results confirm that carding causes more fiber damage or strength loss than other processes examined. The breaking load of fibers in combed sliver may be significantly higher than that in carded sliver, because combing breaks weak fibers damaged in carding and increases the average fiber diameter in combed sliver by removing some fine fibers. An attempt is made to generate an ideal bundle strength profile from single fiber tensile curves. Compared with the tensile curve of the ideal fiber bundle, the tensile curve of an actual wool bundle shows a relatively higher elongation and lower tenacity, probably due to the between-fiber interactions and relatively poorer fiber orientation in the actual wool bundle. A method of minimizing fiber interaction during bundle strength testing is proposed.
Animal Fiber Analysis Using Imaging Techniques
Authors: Robson D.
Published: March 2008

The assessment of fiber scale height is known to be a key ingredient in animal fiber analysis, particularly when quantifying speciality fiber/wool blends. This paper ex plores the potential role of imaging techniques in scale height measurement. High magnification fiber images are captured from a SEM, and imaging techniques are applied and critically evaluated. A systematic, semi-automatic image capture, pro cessing, and analysis approach enables measurement of scale height and scale pattern features for two specific animal fiber types and the creation of information databases. Linear discriminant statistical techniques allow assessment of database integrity and the implementation of "unknown" fiber classification strategies. Adding scale height data to scale pattern data improves database integrity and permits correct classification of a larger proportion of "unknowns."
Weavability Limit of Yarns with Thickness Variation in Shuttleless Weaving: The Single Filling Yarn Feeder Case
Authors: Seyam Abdelfattah M.
Published: March 2008

Recent developments have allowed air-jet weaving machines to handle filling yams with thickness variations, thus joining the solid shuttleless weaving systems in producing fabrics from novelty filling yarns. The increasing popularity of shuttleless weaving technologies and their ability to weave such filling yams has created a need to expand the weavability limit theory to fabrics constructed on shuttleless weaving machines. In this paper, theoretical weavability limit relationships of such fabrics are derived in terms of warp and filling cover factors, warp and filling yam characteristics, and the distribution of thick and thin places of filling yam over the fabric surface.
A New Orientation Density Function of Ideally Migrating Fibers to Predict Yarn Mechanical Behavior
Authors: Boong Soo Jeon  , Jun Young Lee
Published: March 2008

An orientation density function of migrating fibers is newly defined to predict the mechanical behavior of yam. Applying the new function to yam with a helical structure produces the same results as the existing theories, and the function is applicable to even more general cases. Ideal migration behavior is mathematically analyzed by introducing two parameters that describe the migration behavior of fibers in the directions of the yarn axis and the yam's radial axis. The relative initial tensile modulus of the migrating yarn is calculated by applying two parameters to the orientation density function. The relative initial modulus depends strongly on both the migration period in the direction of the yarn axis and the degree of migration in the direction of the yam's radial axis.
Modeling the Creasing Properties of Woven Fabrics
Authors: Feng Jun Shi  , Jinlian Hu  , Tongxi Yu
Published: March 2008

Based on the semicircular form for a fabric bend, the model established by Chapman and Hearle is improved by considering that bending starts from a finite radius. The relationship between creasing behavior and deformation is deduced and solutions are given for a linearly elastic material with constant internal frictional constraint, and then the improved model is applied to the creasing of semicircular and looped specimens made of different fabrics. Pure bending parameters measured on the KEs system are used for the calculations. Agreement between theoretical predictions and experimental results is very satisfactory.
Cotton Color Grading with a Neural Network
Authors: Xu B. , Su J. , Dale D.S. , Watson M.D.
Published: March 2008

It is well known that disagreements about cotton color grades between high volume instruments and classers are substantial, and these machine-classer disagreements deter full acceptance of machine grading of cotton color. This paper provides first a quantitative analysis of the distributions of these disagreements across all the color grades, both major and subcolor categories. The study proves that the disagreements can be both systematic and random, and further analyzes the possible sources for them. Second, the paper introduces a novel design of a neural network classifier for cotton color classification. This classifier consists of multiple networks performing a two-step classification that identifies major and subcolor categories separately. The classifier can be trained by any desirable data. In this research, it is trained using a set of classers' grades, and it exhibits good generalization for the new testing data. The classifier seems to reduce machine-classer disagreements to a minimal level, which is limited by the classer's reproducibility.
Effects of Heat and Moisture Transport in Fabrics and Garments Determined with a Vertical Plate Sweating Skin Model
Authors: Yoo H.S. , Hu Y.S. , Kim E.A.
Published: March 2008

A vertical sweating skin model is developed and changes in vapor pressure within a clothing system are measured to investigate the effects of fiber type, air layer thickness, and garment openings on the microclimate. Cotton broadcloth, polyester broadcloth and cotton canvas are considered. Openings of a garment, such as neck, armhole and waist, are simulated, and the total openness is controlled at 0, 10, 20, 40, and 60%. To evaluate changes in the microclimate of the clothing system, a buffering index Kd and the efficiency of openness are determined. Results show that the buffering index of polyester is higher than that of cotton. As the thickness of the air layer increases, the buffering index increases but an unnecessarily large air gap does not increase the buffering capacity efficiently. As the openness increases, the effect of fabrics on the microclimate decreases gradually, losing its effect at 60% and approached the value of nude skin.
Protective Effect of Maleic Acid Derivatives on the Properties of Wool Fabric Dyed at 120°C
Authors: Liao Q. , Chen L.L. , Shen G.Q. , Brady P.R. , Pailthorpe M.T.
Published: March 2008

Eleven maleic acid derivatives are synthesized and authenticated, then used as wool protective agents for dyeing wool at 120°C with Isolan Red S-RL. The protective effects are evaluated in terms of tensile properties (initial modulus, tensile strength, extension at break, and work to rupture) for both conditioned and wet-state fabrics, chemical damage is assessed in terms of alkali solubility, and hygral expansion is also measured. N-naphthyl and trifluorophenyl maleamic acid and N-benzyl and N-trifluorophenyl maleimides pro vide beneficial effects in terms of increased tensile strength, reduced hygral expansion, and minimal yellowing. However, N-benzyl and N-trifluorophenyl maleimides produce higher alkali solubilities. These results are in contrast to those for Irgasol HTW NEW treated wool, which has relatively low alkali solubility yet higher hygral expansion and poorer tensile properties.
Crosslinking Analysis of Polycarboxylic Acid Durable Press Finishing of Cotton Fabrics and Strength Retention Improvement
Authors: Weilin Xu  , Yi Li
Published: March 2008

Cotton fabric is treated in different concentrations of BTCA and SHP solutions. The fabric weight gain is confirmed by FTIR analysis, and the peak ratio of 1720 cm-1/1380 cm-1 has a good linear relation with fabric weight gain. The results show that BTCA is most effective for durable press finishing at around 2%. The moisture regain of the treated fabric decreases as the weight gain increases before 10%, and then increases at high levels of weight gain. These results indicate that except for inter- and intramolecular crosslinking, some side grafts are formed during the treatment, and at BTCA high concentrations, the quantity of side grafts increases. When the fabric is cured in tension, the intramolecular crosslinks can be reduced and the treated fabric's strength retention can improve from 45% to above 75%.
Effects of Yarn Bending and Fabric Structure on the Bending Properties of Plain and Rib Knitted Fabrics
Authors: Alimaa D. , Matsuo T. , Nakajima M. , Takahashi M.
Published: March 2008

This work deals with the bending properties of a series of plain and rib weft knitted structures made from cashmere yarns. Additionally, some plain weft knitted fabrics made from polyester textured yarns (PET) are included for comparison. The experimental results are discussed in terms of the structural characteristics (cover factor, fabric weight) and their effects on the bending properties. Theoretical analyses of the effects of yarn bending properties and fabric structure on the bending rigidity and frictional bending moment of the fabrics are based on our straight parallel yarns (SPY) model. In this model, the knitted structure is assumed to consist of a series of straight yarns that have some overlapping regions at the interlocking points. The estimation of fabric bending parameters is based on summing up the bending parameters of these straight yarns, which have some overlapping regions lying in the direction of bending. The estimated values from this model are compared with the values measured on a KES-FB pure bending tester; the predictions are in a reasonable agreement with the experimental data.
Hollow Yarn in Friction Spinning
Authors: Merati Ali Akbar , Okamura Masaaki
Published: March 2008

"Hollow" yams have been created to improve cotton yam properties, to increase the entrapped air in the yam, and to gain a stronger yam for spinning and weaving processes. Hollow yams are spun by introducing PVA filaments into the yam-forming zone of an experimental friction spinning apparatus. A 61/18-denier (6.8 tex) PVA multifilament is used as the core and cotton fibers form the sheath. The water soluble PVA in the center is removed from the yam structure in boiling water with a good extraction of more than 95%. The effect of the PVA proportion on the mechanical properties of the hollow yam is examined, and its properties are compared with those of conventional cotton yams. The results show that the strength of the yam before boiling significantly increases as the PVA percentage increases, and it is more than that of an equivalent conventional cotton yarn. The strength of the hollow yam after PVA extraction does not change with the PVA content, and it is the same as that of the equivalent cotton yam. At a high filament percentage, the breaking elongation of the hollow yam is more than that of the cotton yarn.
Model Reduction and Controller Design of a Whole Roller Carding System
Authors: Kuo Chung-Feng Jeffrey , Hsieh Chien-Teng
Published: March 2008

A central idea involved in the design of a dynamic system is the modeling and manipulation of that system. By applying physical laws to a specific system, it is possible to develop a mathematical model that describes the system dynamics. Because a model must be a simplification of reality, there is a great deal of creative art in constructing models. This paper presents a good approach to simplifying a whole roller carding system. It proposes a novel technique to obtain a corresponding single degree of freedom model estimated from a high-order system. This model provides a computationally efficient and conceptually simple algorithm, which for system design purposes yields an appropriate estimation of a high-order linear system.
Infrared Analysis of Aqueous Textile Processing Solutions Using a ZnSe Horizontal ATR Cell
Authors: Eun Kyung Choe  , So Young You  , Beom Soo Lee
Published: March 2008

Although water-based solutions are frequently encountered in textile processes, ana lyzing aqueous solutions is considered to be a difficult task with infrared spectroscopy because of the high absorptivity of the water spectrum and the general incompatibility of water with common infrared cell materials. In this study, textile processing solutions, including indigo dye solutions and polyester caustification wastewater, are analyzed by an infrared method using a trough-type ZnSe horizontal ATR cell. IR spectra of the indigo dye solution feature two intense sulfite and sulfate peaks occurring at 937 and 1100 cm-1, respectively. These peaks provide an easy way to determine the optimum vatting condi tions as well as to estimate the degree of ageing of indigo stock and dyebath solutions. The ethylene glycol component in polyester caustification wastewater is also conveniently measured quantitatively or semiquantitatively by IR analysis without laborious sample preparation.
Quantifying Wetting and Wicking Phenomena in Cotton Terry as Affected by Fabric Conditioner Treatment
Authors: Van Der Meeren Paul , Cocquyt Jan , Flores Silvia , Demeyere Hugo , Declercq Marc
Published: March 2008

To enable the simultaneous determination of both the speed and extent of liquid absorption in cotton fabrics, we have developed a radial, horizontal wicking experiment. The initial part of the absorbed mass versus time profile is linear, which allows us to determine the wicking rate. After a given time, a constant mass is reached, corresponding to the liquid absorption capacity of the fabric. Using the method proposed, we show that a fabric conditioner does not affect the physical characteristics. such as porosity and pore size, and hence the water absorption capacity of cotton terry. On the other hand, there is a pronounced effect on the wicking rate. Based on the experimentally determined values of the contact angle of water on the treated fabrics, the differences in wicking rates as a function of the kind of fabric conditioner can be ascribed to differences in wettability.