bluuebunny/crossref_metadata_2025 huggingface dataset:
ABSTRACTS: J - S I G S AM Japanese Special Interest Group on Symbolic and Algebraic Computation and Report of the Last Seasonal Meeting
Authors: Winkler Franz
Published: January 2007

In September, 1984, Japanese SIGSAM was formed in Japan Society of Software Science and Technology. The first chairman is Dr. Tateaki Sasaki, The Institute of Physical and Chemical Research, and the working committee members are Dr. Naoto Niki, The Institute of Statistical Mathematics, Prof. Hidetsune Kobayashi, Department of Mathematics, Nihon University, Mr. Yoshinari Fukui, Total Information System Division, Toshiba Corporation, and Mr. Akio Furukawa, Department of Mathematics, Tokyo Metropolitan University. The number of members is about 40 now, from the fields of mathematics, mathematical sciences, physics, and technology. In each year, the group organizes four meetings and the biggest event is the three-day meeting at RIMS, Kyoto University. In each meeting, we have 30 ~ 50 attendants (not only J-SIGSAM members but also non-members), and 3 ~ 5 papers are presented in each day. The last meeting was held on February 26, 1987, at The Institute of Physical and Chemical Research (see below for the titles and abstracts of the papers presented). Recently, we had an election for the J-SIGSAM chairman, and Prof. Morio Nagata, Department of Science and Technology, Keio University, has been elected as the new chairman.
Admissible orders and linear forms
Authors: Weispfenning Volker
Published: January 2007

Admissible orders on terms (power-products of finitely many indeterminates X
1
,..., X
n
play a fundamental role in the definition and construction of Groebner bases for polynomial ideals (see [Bul). By passage to exponents, these orders may be construed as linear orders on [EQUATION] compatible with addition and with smallest element [EQUATION] = (0,...,0). Any such order extends uniquely to a linear order < on [EQUATION] turning ([EQUATION], +, >) into an ordered group such that all elements of [EQUATION] are non-negative, Conversely, any restriction of such an order to [EQUATION] is an admissible order on [EQUATION]. So from now on an "admissible order" will be a linear group order on [EQUATION] with [EQUATION] >= 0.
A knowledge-based system for computer algebra
Authors: Calmet Jacques , Lugiez Denis
Published: January 2007

This paper reports on a work in progress aiming at designing and implementing a system for representing and manipulating mathematical knowledge. Its kernel is a computer algebra system but it shows several of the features of the so-called knowledge-based systems. The main issues considered here are the software engineering aspects of the project, the definition of a new language to support the system and the use of AI techniques in a field where algebraic algorithms are the building stones of systems. This defines an environment which enables not only to have data-bases of knowledge but also to implement an expert use of this knowledge.
Fortran 8X—the emerging standard
Authors: Metcalf M
Published: January 2007

Since 1979, the Fortran standardization committee, X3J3, has been labouring over a draft for the next version of the standard. Its initial intention of publishing this draft in 1982 was hopelessly optimistic, and at best it may be ready this year. However, a number of fundamental issues have been thrown up over the past two years, such that it is clear that unanimity cannot be achieved: efficiency versus functionality; safety versus obsolescence; small and simple or big and powerful?This paper reviews the current state and content of Fortran 8x, and attempts to bring out some of the controversial issues surrounding its development.
Software reuse through information retrieval
Authors: Frakes W B , Nejmeh B A
Published: January 2007

There is widespread need for safe, verifiable, efficient, and reliable software that can be delivered in a timely manner. Software reuse can make a valuable contrbution toward this goal by increasing programmer productivity and software quality. Unfortunately, the amount of software reuse currently done is quite small. DeMarco [1] estimates that in the average software development environment only about five percent of code is reused.
Some observations on retrieval from a large technical document database
Authors: Marcus R
Published: January 2007

The problem of retrieving documents from a large document database is an important problem that has been the subject of some controversy in the recent literature. See [1] and [2]. The basic question has been whether manual indexing is necessary to overcome the weaknesses of full-text retrieval. The problem with full-text retrieval is that in order to narrow down the number of documents selected to a reasonable size, it is necessary to choose a specialized set of keywords. This restrictive search means that relevant documents will often be missed due to misspellings, alternate terms, typing errors, etc.Manual indexing would seem to provide a solution to this problem by allowing a document to be retrieved using a human assigned index term or terms describing its content. Unfortunately, experiments have shown that manual indexing is often subject to the same problems as full-text retrieval due to the variation in index terms chosen by different people for the same document. An even more serious problem for a very large technical domain with many documents is the difficulty in creating and maintaining coherent indexes that can describe the whole domain.This paper will summarize the experience that has been gained from studying document retrieval in the domain of computer software support. The database is accessed by engineers searching to see if a current problem has occurred and been solved in the past. An extensive study of how documents are submitted and retrieved has brought to light some general principles that can improve the performance of the system. These principles which combine manual indexing and full-text retrieval will be discussed in the remainder of this paper.
Window sharing with collaborative interface agents
Authors: Rich Charles
Published: January 2007

An implemented system is described which allows a software agent to collaborate with a human user using a shared application window. The system automatically controls input permission and also provides mechanisms for signalling and communication. A generalization of the system to multiple users and agents, called NShare, is compared with common window-sharing tools, such as SharedX. This work is part of a larger agenda to apply principles of human collaboration and discourse structure to human-computer interaction using the interface agent paradigm.
Personal computers and data processing departments: interfaces, impact and implications
Authors: Chandra Satish
Published: January 2007

The impact of the rapidly growing use of personal computers on data processing (DP) departments is analyzed using data from a national survey of DP managers. The implications of the findings are discussed in the context of policy and managing personal computers and DP departments.
An inexpert system for system development
Authors: Ought E.D.
Published: January 2007

This paper explores the concept of inexpert systems which accumulate ignorance and misunderstanding. Capitalizing on the work of N. Worthy and N. Nowen (1985), the idea of an intelligence-avoiding system is applied to a number of common hard problems, formost among which is the development of accounting systems by trained COBOL programmers.
Reuse in a simulation environment for flexible manufacturing systems
Authors: Kopácsi Sándor , Gavalocová Daniela , Kovács George L. , Kmecs Ildikó
Published: January 2007

Software developers often meet the problem of creating new components of an application that someone probably has already produced. Without having effective reuse tools usually it is more natural to create new components from scratch than to seek for useful elements in other programmes and/or systems.In the field of simulation of Flexible Manufacturing Systems (FMS) this issue often occurs, when different systems with some similar features have to be managed. FMSs are highly automated production systems with minimal human control. FMS usually consist Flexible Manufacturing Cells (FMCs). An FMC is considered as a group of one or more machine tools, robots, adjacent mechanical elements, tool and fixture supporting workstations and an internal transport system.The components of different FMSs and FMCs are the same type of machine tools, transfer equipment, etc. In the relevant aspects they usually differ from each other only in their amounts and working parameters. This fact itself breeds the idea of reuse of FMS and FMC simulation model elements.Simulation can be used for analysing the behaviour of an existing or would-be system. It is useful for calculating utilisation statistics, finding bottlenecks, pointing out scheduling errors, and even for creating manufacturing schedules. Simulation is a very effective technique for dynamic analysis, but it is short of optimising ability. A satisfactory solution can be obtained through modelling and simulating alternative approaches with iteration.There are many concepts, object classes, and lines of source code created, that could be reused in the new applications. Usage of reuse methodology and practice will reduce our efforts in developing new systems.In this paper the reuse of the components of simulation models in a hybrid simulation and scheduling system for new simulation applications will be introduced. This simulation-scheduler system has been implemented as a combination of a traditional simulation language (SIMAN/Cinema) and an intelligent expert environment (G2). The design methodology used for model development is based on the object-oriented Rational Rose CASE tool and on a use-case model.
Problems, puzzles, challenges
Authors: Fee G. J. , Managan M. B.
Published: January 2007

This new section is for the submission of problems, puzzles and challenges for our computer algebra systems to solve, and for publishing the computer solutions to the above. We start the problem section by presenting some problems that appear at first glance to be purely numerical, that is they look like they should be solvable by using a purely numerical package. However, you may find that this just leads to an error message when you try to solve them using a purely numerical package. Can our computer algebra systems come to the rescue and solve the following problems?
Gridless detail routing with a front
Authors: Lass S
Published: January 2007

Detail routing is performed one layer at a time by moving a front across a layer. The front (similar to a line) is orthogonal to the connections being routed. The front approach described here is gridless, includes shove aside, supports variable width lines, and has modest memory requirements.
OCCUPATIONAL STRESS IN THE INFORMATION SYSTEMS PROFESSION
Authors: Lo Man-Wan
Published: January 2007

The proliferation and growing use of computers and information systems in organizations have changed the way people live --- in offices, factories, schools, libraries, banks, homes, and other facets of daily life. It has also generated an increasing demand for information systems professionals to manage and implement the technology. To avoid potential health hazards, it is essential that people understand the possible consequences of spending long hours with this new technology.
DATABASE QUERY COMPOSITION AND THE ROLE OF USER VIEW OF DATA
Authors: Smelcer John B.
Published: January 2007

In spite of years of research aimed at improving database query languages (Boyle, Bury & Evey, 1983; Reisner, Boyce & Chamberlin, 1975; Thomas & Gould, 1975; Welty & Stemple, 1981; Welty, 1985), users still make mistakes. They consistently err when writing queries requiring information about two (or more) different entities, e.g., "What are the locations of all products?" Users not only have to learn a query language, but have to learn the structure of their data (called the user view of data) and then match the language with the data (Ogden, 1986). Current results (Smelcer & Mantei, 1984) indicate that designers and users of databases think about the same data differently; users expect the user view to be organized in one way, but it is actually organized in a different way. Database administrators need guidelines for creating user views of data, which enable users to more easily understand the organization of their data, and more easily write queries to access their data.
COGNITIVE STYLE AS A FACTOR IN RESISTANCE TO AUTOMATION IN HUMAN SERVICES
Authors: Hammer Allen L.
Published: January 2007

Despite a plethora of computer applications proposed or implemented in human service settings, it was observed that resistance to automation remains high among practitioners. Such resistance is a critical issue because of the high costs of developing, implementing and maintaining automated systems. The need to find a solution to the resistance problem will increase as human service organizations face increasing demands for accountability. Demands that, it has been suggested, can only be met through the employment of automated systems.
THE USE OF MENTAL MODELS TO ENHANCE HUMAN-COMPUTER INTERACTION
Authors: Coovert Michael D.
Published: January 2007

The approach taken in this research is to increase the quality of human-computer interaction through having the computer software match or emulate the cognitive representation employed by the user population. We believe that through interacting with users through the users' own cognitive representation of the information or knowledge, the users' perceptions of the interaction will be enhanced. Furthermore, if psychological theories of how users encode and represent knowledge are correct, the quality of information retrieved by users will increase, due to less inhibition, distortion, and reliance on constructive memory. The key is finding the representation employed by the user population. Once the scheme is known, it can be incorporated into the system and used to guide the interaction process.
Dialog management in interactive systems: a comparative survey
Authors: Britts Stefan
Published: January 2007

Developing interactive systems is very expensive. This stems from the fact that, in average, 50--60 per cent of the lines of code in an application are for dialog management [Sutto77]. Therefore, dialog development has been recognized as an important area both among researchers and practitioneers. As a result, many tools have been developed, or are under development, with the aim of reducing the dialog design and implementation efforts, and hence, reducing the costs.
An undergraduate course in software psychology
Authors: Hewett Thomas T
Published: January 2007

Some years ago I undertook to develop a course in Software Psychology. Originally using the model in Shneiderman's book (1980), I gradually modified the course to suit my own interests and conception of the field. Currently, the course focuses on two issues---the cognitive psychology of computer programming and the application of cognitive psychology to design and evaluation of Human-Computer Interfaces, with greatest emphasis upon interface design and evaluation. Currently, the ten week course involves a mixed lecture, discussion, and demonstration format with students doing a short written critique of an application program, a mid-term examination, a final examination, and a design project.
Report on the workshop on design & performance issues in parallel architectures
Authors: Tripathi Satish K , Kaisler Steve , Chandran Sharat , Agrawala Ashok K
Published: January 2007

Machines that perform computations in parallel have come into vogue today partly prodded by technology and user needs. In the early spring of '86, a workshop was held under the auspices of the University of Maryland Institute for Advanced Computer Studies (UMIACS) to investigate the design and the notusually-addressed issue of the performance of these machines. This report serves as a record of the workshop though it does not promise to be a transcript of the various sessions. About a dozen presentations interspersed with sprited open-forum discussions have been paraphrased here. It is hoped that this report remains faithful to the proceedings.
Song of the whale
Authors: Gjerløv Per , Meisel Izabela
Published: January 2007

APL2 has often been used in a credit course at the Technical University of Denmark. The objective of the course exercise has been to analyze the vocalizations of Sperm Whales. In January 1996 the course was run again, this time using the IBM SP/2 supercomputer to solve the problem, and in this course an additional objective was to utilize the possibilities of this powerful parallel computer.During the three weeks of the course the students learned the APL language, solved a non-trivial problem, used a very powerful computer for the solution and wrote excellent and detailed reports.
Classifier systems and economic modeling
Authors: Mitlöhner Johann
Published: January 2007

Human economic decisions are characterized by a number of factors which make them difficult to model with standard mathematical tools. Decisions can be more easily described by a set of rules, and some of them may be "rules of thumb". Economic behavior is adaptive, in that people are able to adjust to a changing environment. It is argued in this paper that the classifier system framework is a suitable means of modeling human economic decisions. A case of a simple economic decision of finding an optimal price is discussed, which is later made more complex by introducing an input variable that effects the optimal price. It is shown that classifier systems can be used in both tasks, and their performance is compared to human decisions in the same set of circumstances.
An integrated business application architecture
Authors: Cheng Wei-Tih
Published: January 2007

An integrated business application architecture has been implemented in the Information Systems and Communications Group and the Information Systems and Products Group, two of IBM's group headquarters. The language base used is APL so that the maximum productivity can be achieved. The cornerstone of this architecture is an APL-based graphics package called A Presentation Graphics System (APGS). The architecture is a closed-loop system with the flexibility to expand as more application systems are needed. Increases in productivity and quality have been realized through the implementation of this architecture for both the management, the planning staff and the application programmers.
Integrating ordinary type and many languages with the APL alphabet and keyboard
Authors: Berry Paul
Published: January 2007

To enjoy the advantages of APL, for too many years the APL user has had to forego “ordinary” characters and keyboards. This has been a major inconvenience to English-speaking North Americans, who have had to adjust to an unconventional keyboard and a character set without lower case, and even worse for Europeans, who found their national keyboards ignored and their national characters unrecognized.

With improvements in technology, a change of orientation is possible. Where formerly APL was conceived as a closed system, independent of everybody else's typography, now it is possible to integrate APL with each nation's standard keyboard. This paper proposes a return to conventional lowercase and caps for APL alphabetics, keyboards that offer APL characters without disturbing conventional layouts, and a major expansion of the APL character set to embrace the characters of a world-wide set of languages.
APLIM—applied linear interactive models
Authors: Ansell J. I. , Sykes A. M.
Published: January 2007

Regression is the most frequently and widely applied technique in Statistics. The field of applications range from experimental design (historically in agriculture) to financial modelling. The technique has been greatly enhanced by the radical approach due to Nelder and Wedderburn. Their approach unified many apparently disparate applications of linear models to produce the Generalized Linear Model. Others have subsequently expanded their work. The paper briefly reviews this work indicating the main features which should be of interest to practitioners in many disciplines, e.g. education, sociology, medicine, economics, and the sciences.

The original software developed from this approach was written in FORTRAN which the present authors believe constrained the development of a truly interactive package. APLIM, the first commercial APL version of the Generalized Linear Model is described. Stress is placed on a “user friendly” approach throughout the package.

The authors have used APLIM to teach undergraduate students at the College Generalized Models, and a taste of their present teaching approach is given. The software has already been tested internally at the college by allowing other research workers access to it.

The authors are at present working on a version for the IBM PC, aided by IBM UK.
A group of APL functions for computer-assisted instruction
Authors: Grannell Vin
Published: January 2007

Computer-Assisted Instruction is claimed to be an important application of APL on microcomputers. Features are described that make APL the language of choice for one type of computer-assisted instruction.
An APL production environment
Authors: Olavi Gösta
Published: January 2007

Production usage of an APL application has further requirements than test execution by the programmer. Normally, each application implements its own production-environment features. This paper discusses the advantages of separating such features from the applications, and to supply them via a standardized production environment. One specific such environment, implemented at Skandinaviska Enskilda Banken, is described.
≅USER
Authors: Neurdenburg Jan-Willem , Schwarz Phil S.
Published: January 2007

This paper describes the implementation of an APL interface to user-provided subroutines written in a language other than APL. The user's subroutines are incorporated directly into the APL interpreter, yet the interface is implemented in a way which prevents such problems as unintentional corruption of the APL workspace. Examples illustrate the use in APL. via the interface, of Data General's GKS (Graphical Kernel System) subroutine package, a flexible, powerful, standard-compliant library of graphics subroutines for compiled languages.
Architecture issues in multimedia storage systems
Authors: Özden Banu , Rastogi Rajeev , Silberschatz Avi
Published: January 2007

Next generation storage systems will need to provide support for both textual data and other types of multimedia data (e.g., images, video, audio). These two types of data differ in their characteristics, and hence require different techniques for their organization and management. In this paper, we provide an overview of 1) how storage systems can be architectured to support multimedia data, and 2) what are the main challenges in devising new algorithms to manage multimedia data. In order to provide rate guarantees for continuous media data, an admission control scheme must be employed that determines, for each client, whether there are sufficient resources available to service that client. To maximize the number of clients that can be admitted concurrently, the various system resources must be allocated and scheduled carefully. In terms of disks, we use algorithms for retrieving/storing data from/to disks that reduce seek latency time and eliminate rotational delay, thereby providing high throughput. In terms of main-memory, we use buffer management schemes that exploit the sequential access patterns for continuous media data, thereby resulting in efficient replacement of buffer pages from the cache.
A diagnostic system based on a multi-decision approximate rules model
Authors: Hashemi Ray R. , Choobineh Fred , Talburt John , Slikker William , Paule Merle G.
Published: January 2007

Modified Rough Sets (MRS)-based diagnostic systems eliminated many of the limitations of Rough Sets (RS)-based, statistical-based, and decision tree-based systems and because of that, they have a better performance. In contrast with the other systems, MRS-based diagnostic systems have potential to handle Multi-Decision Approximate (MDA) rules. In this paper, we (1) develop a diagnostic model based on MDA rules and (2) evaluate the classification power of the model.
A blueprint for automatic indexing
Authors: Salton G.
Published: January 2007

This note summarizes some of the currently available insights in automatic indexing. The emphasis is on aspects that are expected to be useful in practical automatic indexing applications. The discussion is necessarily cursory, but the references will lead interested readers to a deeper treatment of the indexing problem.
Biological Neural Networks in Invertebrate Neuroethology and Robotics. Editors: Randall D. Beer, Roy E. Ritzmann, Thomas McKenna (Academic Press, Inc., Harcourt Brace Jovanovich, 1993)
Authors: Becker Glenn
Published: January 2007

This book is the result of a workshop held in the fall of 1991 at the National Academy of Sciences Study Center in Woods Hole, MA. The workshop was entitled "Locomotion Control of Legged Invertebrates" and it was sponsored by the Office of Naval Research. The purpose of the workshop was to bring together researchers studying neural control of sensory and motor systems in invertebrates and researchers building legged robots. This type of cross-discipline work is often beneficial for both groups. Researchers in robotics and artificial intelligence borrow regularly from biological systems. Likewise, researchers studying neurological systems often benefit from computer models of control systems. These models can be controlled and manipulated much more easily than their biological counter-parts.
Book review: Design and Implementation of Intelligent Manufacturing Systems: From Expert Systems, Neural Networks, to Fuzzy Logic. Volume 6, Environmental and Intelligent Manufacturing Systems Series. Hamid R. Parsaei and Moharnmad Jamshidi, editors. (Prentice Hall PTR, 1995)
Authors: Van Dyke Parunak H.
Published: January 2007

Manufacturing is one of the few activities in an economy that generates real wealth (as opposed to shuffling existing wealth around). Research on ways to do it better is of the utmost social interest, and advanced techniques of machine intelligence have much to offer this agenda. So this volume's title generates great expectations. Readers deserve chapters outlining path-breaking research contributions in industrial-strength machine intelligence, and discussions of how existing AI techniques can be translated into the nitty-gritty domain of real-world application. Several articles in this volume of contributed essays do satisfy these expectations, but most fall short, either because they do not use computational techniques that one would recognize as "intelligent," apply established AI techniques to toy problems of little practical concern in industry, or both.
An efficient algorithm for managing partial orders in planning
Authors: Fox Maria , Long Derek
Published: January 2007

Partial orders are an essential supporting component of non-linear, constraint-posting planning algorithms. However, managing partial orders represents and expensive overhead in plan construction and development. Simple solutions are only suitable for very small planning problems involving tens rather than hundreds of partially ordered elements. For more sophisticated planning languages allowing the representation of point-based intervals and abstraction it is necessary to manage far larger sets of temporal elements. In this paper is presented an approach and algorithm, TEMPMAN, for the management of partial orders which exploits the typical properties of planned partial orders to achieve a significantly better performance than existing solutions to this problem.
A distributed numerical/simulative algorithm for the analysis of large continuous time Markov chains
Authors: Buchholz Peter
Published: January 2007

A distributed algorithm is introduced for the analysis of large continuous time Markov chains (CTMCs) by combining in some sense numerical solution techniques and simulation. CTMCs are described as a set of processes communicating via message passing. The state of a process is described by a probability distribution over a set of reachable states rather than by a single state. Simulation is used to determine event times and messages types to be exchanged, whereas transitions are realized by vector matrix products as in iterative numerical analysis techniques. In this way, the state space explosion of numerical analysis is avoided, but it is still possible to determine more detailed results than with simulation. Parallelization of the algorithm is realized applying a conservative synchronization scheme, which exploits the possibility of precomputing event times as already proposed for parallel simulation of CTMCs. In contrast to a pure simulation approach, the amount of computation is increased, whereas the amount of communication keeps constant. Hence it is possible to achieve even on a workstation cluster a significant speedup.
The threshold of event simultaneity
Authors: Wieland Frederick
Published: January 2007

We revisit the notion of event simultaneity in the context of parallel and distributed simulation. Although the simulation community has recognized this problem for years, it has focused mainly on the mechanics of breaking event-time ties and has neither measured its extent nor considered its implications. Exant simulators (both serial and parallel) prohibit simultaneity either by user-specified event priorities or by an arbitrary (but well-documented) tie-breaking mechanism. We show, theoretically and empirically, that these strategies may lead to an invalid simulation. In doing so, we introduce the threshold of event simultaneity and use it to understand the semantics of simultaneity.
Distributed simulation of spatially explicit ecological models
Authors: Glass Kevin , Livingston Marilynn , Conery John
Published: January 2007

Large-scale ecological simulations are natural candidates for distributed discrete event simulation. In optimistic simulation of spatially explicit models, a difficult problem arises when individuals migrate between physical regions simulated by different logical processes. We present a solution to this problem that uses shared object states. Shared states allow for efficient communication between LPs and for early detection of canceled events. We briefly describe an optimistic simulation environment called EcoKit, which operates on top of the WarpKit implementation of Time Warp. Our experiments with this system on a shared memory multiprocessor show that EcoKit promises to scale well both with the number of processors and the number of individuals simulated.
Speculative parallel simulation with an adaptive throttle scheme
Authors: Tay Seng Chuan , Teo Yong Meng , Kong Siew Theng
Published: January 2007

Excessive rollback recoveries due to overoptimistic event execution in Time Warp simulators often degrade their runtime performance. This paper presents a two-sided throttling scheme to dynamically adjust the event execution speed of Time Warp simulators. The proposed throttle is based on a new concept called global progress window, which allows the individual simulation process to be positioned on a global time scale, thereby to accelerate or suspend their event execution. As each simulation process can be throttled to a steady state, excessive rollback recoveries due to causality errors can be avoided. To quantify the effect of rollbacks and for purpose of comparing different Time Warp implementations, we propose two new measures called RPE (number of Rollback events Per committed Event), and E (relative Effectiveness in reducing rollback overhead). Our implementation results show that the proposed throttle effectively regulates the proceeding of each simulation process, resulting in a significant reduction in rollback thrashing and elapsed time.
Billiards and related systems on the bulk-synchronous parallel model
Authors: Marín Mauricio
Published: January 2007

With two examples we show the suitability of the bulk-synchronous parallel (BSP) model for discrete-event simulation of homogeneous large-scale systems. This model provides a unifying approach for general purpose parallel computing which in addition to efficient and scalable computation, ensures portability across different parallel architectures. A valuable feature of this approach is a simple cost model that enables precise performance prediction of BSP algorithms. We show both theoretically and empirically that systems with uniform event occurrence among their components, such as colliding hard-spheres and ising-spin models, can be efficiently simulated in practice on current parallel computers supporting the BSP model.
Dag consistent parallel simulation
Authors: Cai Wentong , Letertre Emmanuelle , Turner Stephen J.
Published: January 2007

We present a novel approach to parallel discrete event simulation based on the Cilk model of multithreaded computation. Cilk's runtime system not only manages the low-level aspects of program execution, but also provides the user with an algorithmic model of performance which can be used to predict the execution time of a parallel simulation. Moreover, a Cilk application can ``scale down'' to run on a single processor with nearly the same performance as that of serial code.A conservative parallel discrete event simulation algorithm has been developed in which communication between logical processes is achieved using Cilk's virtual memory model, dag consistent shared memory. The simulation executes in cycles, where each cycle involves a divide and conquer computation. Although local lookahead information can be exploited, the algorithm is robust in that it also calculates a global simulation time for each cycle. It can therefore be used for applications where zero lookahead may occur.
The dark side of risk (what your mother never told you about Time Warp)
Authors: Nicol D. M. , Liu X.
Published: January 2007

This paper is a reminder of the danger of allowing ``risk'' when synchronizing a parallel discrete-event simulation: a simulation code that runs correctly on a serial machine may, when run in parallel, fail catastrophically. This can happen when Time Warp presents an ``inconsistent'' message to an LP, a message that makes absolutely no sense given the LP's state. Failure may result if the simulation modeler did not anticipate the possibility of this inconsistency. While the problem is not new, there has been little discussion of how to deal with it; furthermore the problem may not be evident to new users or potential users of parallel simulation. This paper shows how the problem may occur, and the damage it may cause. We show how one may eliminate inconsistencies due to lagging rollbacks and stale state, but then show that so long as risk is allowed it is still possible for an LP to be placed in a state that is inconsistent with model semantics, again making it vulnerable to failure. We finally show how simulation code can be tested to ensure safe execution under a risk-free protocol. Whether risky or risk-free, we conclude that under current practice the development of correct and safe parallel simulation code is not transparent to the modeler; certain protections must be included in model code or model testing that are not rigorously necessary if the simulation were executed only serially.
Drowning in our success
Authors: Ashworth Jayne
Published: January 2007

College and university computing support providers are discovering these days what Walt Kelly's Pogo character said many years ago: "We have met the enemy and he is US." We who work in support of computing activities in higher education may have been overly successful in helping to integrate the use of computer technology into all facets of academic life as we must now work with the situations that are happening as a result of our communities embracing this technology.
Breathless in Oberlin (and Seattle, and New York, and Podunk)
Authors: Bucher John
Published: January 2007

Preface note: The following is an article that was recently published in
The Observer
, the faculty and staff bi-weekly newspaper of Oberlin College. I wrote it to explain the "service support crisis" to our campus community and I offer it as an example of the kind of proactive work we need to take on our campuses to deal with the crisis. It is reprinted here exactly as it appeared in The Observer.
Share the documentation load
Authors: Hales Susan , Novogrodsky Seth , Colgrove Johanna
Published: January 2007

Do you write computing documentation? Edit a newsletter? Put together "Getting Started" or "Quick Tips" handouts? If so, we'd like to invite you to join the DocShare Consortium.
Prediction of attention in autism from single-trial EEG using artificial neural networks
Authors: Belmonte Matthew
Published: January 2007

Two-layer and three-layer feed-forward artificial neural networks were trained to predict behvioural performance from singletrial EEG in autistic and normal subjects in a task involving response to rare stimuli and shifting of attention between vision and audition. Eyeblink artefacts were removed from the data using a frequency-domain filter. Performances of the networks on separate test sets varied across subjects but were usually at least 80%. The networks usually converged faster and attained a somewhat greater level of performance when input was presented in the frequency domain instead of in the time domain. Analysis of the network's failures in classifying the autistic auditory data turned up a variable response in which N270 and P700 were only occasionally present.
Exploring time series analysis using APL
Authors: Robinson Lew
Published: January 2007

Time series often occur which exhibit some sort of "seasonality" pattern. Circadian or calendarial influences are frequently present. Derived from the generic circulant form, quasi-circulant matrices can directly and uniquely separate such seasonality from trend in the observations. The methodology is developed in APL and then applied to atmospheric lead data. Results are plotted, tabulated and discussed.
Extracting formal domain models from exsisting code for generative reuse
Authors: Devanbu Prem , Frakes Bill
Published: January 2007

The existence of a
domain model
that formally describes the meaning of a piece of software can be helpful for re-use. We illustrate an approach, where by reengineering a formal domain model out of an existing system, one can generalize the existing system to an application generator: we map a domain model for program representations into the front end of a compiler, using the
Genii
system, and use this in
Genoa
, an application generator for language tools. This approach shows promise in other domains, as well.
Experimental evaluation of the Hewlett-Parkard exemplar file system
Authors: Bordawekar Rajesh , Landherr Steven , Capps Don , Davis Mark
Published: January 2007

This article presents results from an experimental evaluation study of the HP Exemplar file system. Our experiments consist of simple micro-benchmarks that study the impact of various factors on the file system performance. These factors include I/O request/buffer sizes, vectored/non-vectored access patterns, read-ahead policies, multi-threaded (temporally irregular) requests, and architectural issues (cache parameters, NUMA behavior, etc.). Experimental results indicate that the Exemplar file system provides high I/O bandwidth, both for single- and multi-threaded applications. The buffer cache, with prioritized buffer management and large buffer sizes, is effective in exploiting temporal and spatial access localities. The performance of non-contiguous accesses can be improved by either using vectored I/O interfaces or tuning the read-ahead facilities. The file system performance depends on the relative locations of the computing threads and the file system, and also on various Exemplar design parameters such as the NUMA architecture, TLB/data cache management and paging policies.
Book review: Artificial Intelligence by Ian Pratt (The Macmillan Press Ltd, Houndmills, 1994)
Authors: Návrat Pavol
Published: January 2007

With only 280 pages, Pratt's book on artificial intelligence is a rather courageous attempt to offer a textbook for a field which nowadays is frequently covered in substantially bigger texts, e.g. (Russell). The modest size has the effect of emphasizing some subdisciplines of AI over others.
Book review: Fuzzy logic and Neuro Fuzzy Applications Explained by Constantin von Altrock (Prentice Hall 1995)
Authors: Pat.yra Marek
Published: January 2007

Fuzzy Logic and News Fuzzy Applications Explained
presents three major topics: (1) an intuitive introduction to the theory of fuzzy sets, fuzzy logic and fuzzy control; (2) a plethora of engineering applications of fuzzy logic and fuzzy logic-based control, and (3) an introduction to fuzzyTECH
TM
, a software system for development of fuzzy logic-based controllers from INFORM Corporation, Aachen, Germany. A demonstration version of FuzzyTECH with an example is included on 2 diskettes (PC version only).
Book review: Fundamentals of Artificial Neural Networks by Mohamad H. Hassoun (MIT PRESS, 1996)
Authors: Olivas Emilio Sofia
Published: January 2007

The field of artificial neural networks has grown substantially in recent years accompanied by an increased number of neural networks textbooks. These books attempt to give a broad introduction to both the theory and use of neural networks, such as (Hertz, 1991), (Kung, 1993), (Haykin, 1994), and (Rojas, 1996). Hassoun's book, like these, is a very good textbook for first year undergraduate students who are learning the computational abilities of neural networks. In addition it has some value to researchers because recent advances are covered.
TED—a language for modeling telecommunication networks
Authors: Perumalla Kalyan , Fujimoto Richard , Ogielski Andrew
Published: January 2007

TeD
is a language designed mainly for modeling telecommunication networks. The
TeD
language specification is separated into two parts --- (1) a
meta
language (2) an
external
language. The meta language specification is concerned with the high-level description of the structural and behavioral interfaces of various network elements. The external language specification is concerned with the detailed low-level description of the implementation of the structure and behavior of the network elements. In this document, we present an introduction to the
TeD
language, along with a brief tutorial using an example model of a simple ATM multiplexer.
LEEP3—distance education tips
Authors: Woodbury Marsha
Published: January 2007

The Graduate School of Library and Information Science (GSLIS) at the University of Illinois in Urbana-Champaign is reaching out to potential graduate students in Illinois and beyond. GSLIS is developing an experimental model for delivering high-quality professional instruction through its new distance education M.S. scheduling option, LEEP3 (http://alexia.lis.uiuc.edu/LEEP3/index.html). My talk deals with lessons learned during our first few months of instruction.
Abstracts of the 4th East Coast Computer Algebra Day, Northeastern University, Boston, MA, May 3, 1997
Authors: Cooperman Gene
Published: January 2007

A one-day computer algebra workshop was held at Northeastern University on May 3, 1997. The workshop was endorsed by SIGSAM. The workshop included three invited speakers, 12 poster presentations and four software demonstrations. The workshop included 54 participants, from a region roughly bounded by North Carolina, Ohio, Ontario and Maine. Previous workshops in this annual series were held at the University of Delaware, Drexel University, and IBM Watson Research Laboratories. Please contact the organizers to be added to the mailing lists.A Web version of these abstracts will be provided at www.ccs.neu.edu /home/gene/eccad97.html. We gratefully acknowledge the financial support of the National Science Foundation (CCR-9707543), Northeastern University, and the College of Computer Science at Northeastern University.
On calibrating measurements of packet transit times
Authors: Paxson Vern
Published: January 2007

We discuss the problem of detecting errors in measurements of the total delay experienced by packets transmitted through a wide-area network. We assume that we have measurements of the transmission times of a group of packets sent from an originating host,
A,
and a corresponding set of measurements of their arrival times at their destination host,
B,
recorded by two separate clocks. We also assume that we have a similar series of measurements of packets sent from
B
to
A
(as might occur when recording a TCP connection), but we do not assume that the clock at
A
is synchronized with the clock at
B,
nor that they run at the same frequency. We develop robust algorithms for detecting abrupt adjustments to either clock, and for estimating the relative skew between the clocks. By analyzing a large set of measurements of Internet TCP connections, we find that both clock adjustments and relative skew are sufficiently common that failing to detect them can lead to potentially large errors when analyzing packet transit times. We further find that synchronizing clocks using a network time protocol such as NTP does not free them from such errors.
Modeling communication pipeline latency
Authors: Wang Randolph Y. , Krishnamurthy Arvind , Martin Richard P. , Anderson Thomas E. , Culler David E.
Published: January 2007

In this paper, we study how to minimize the latency of a message through a network that consists of a number of store-and-forward stages. This research is especially relevant for today's low overhead communication systems that employ dedicated processing elements for protocol processing. We develop an abstract pipeline model that reveals a crucial performance tradeoff involving the effects of the overhead of the bottleneck stage and the bandwidth of the remaining stages. We exploit this tradeoff to develop a suite of fragmentation algorithms designed to minimize message latency. We also provide an experimental methodology that enables the construction of customized pipeline algorithms that can adapt to the specific system characteristics and application workloads. By applying this methodology to the Myrinet-GAM system, we have improved its latency by up to 51%. Our theoretical framework is also applicable to pipelined systems beyond the context of high speed networks.
Modeling set associative caches behavior for irregular computations
Authors: Fraguela Basilio B. , Doallo Ramón , Zapata Emilio L.
Published: January 2007

While much work has been devoted to the study of cache behavior during the execution of codes with regular access patterns, little attention has been paid to irregular codes. An important portion of these codes are scientific applications that handle compressed sparse matrices. In this work a probabilistic model for the prediction of the number of misses on a
K
-way associative cache memory considering sparse matrices with a uniform or banded distribution is presented. Two different irregular kernels are considered: the sparse matrix-vector product and the transposition of a sparse matrix. The model was validated with simulations on synthetic uniform matrices and banded matrices from the Harwell-Boeing collection.