bluuebunny/crossref_metadata_2025 huggingface dataset:
Book review: Prolog: The Standard Reference Manual By E Deransart, A. Ed-Dbali, and L. Cervoni (Springer-Verlag, 1996)
Authors: Hodgson J. P.E.
Published: January 2007

The ISO Prolog standard took 10 ars to produce. For a language II that, on its face, is both simple and logical this seems like a long time to spend on standardization. While this book is in no sense a history of the standardization of Prolog, it does provide some insight into why the process took so long. Anyone who has tried to learn Prolog knows that to use the language effectively one must have a sound understanding of the computational model. (Of course, this is true of any programming language, but for Protog it seems to be especially so.) The standards group was to find plenty of room for dispute over the computational model. A major service that this book performs is to provide a clear description of the Prolog inference engine.
Book review: The Knowledge Acquisition and Representation Language, KARL. By Dieter Fensel (Kluwer Academic Publishers, 1995)
Authors: Ageenko Ilieva I.
Published: January 2007

The book is based on the author's Ph.D. dissertation and is written primarily for researchers in AI and practitioners in the field of knowledge-based systems development who, in addition to developing knowledge-based systems, also want to understand the model-semantic foundation in the development of knowledge modeling languages. It can also be used as an advanced textbook for knowledge modeling.
A new imaging method and its application in gynecological treatment planning
Authors: Englmeier K. H. , Pöppi S. J.
Published: January 2007

Intracavitary afterloading therapy -- a customary system to treat malignant tumours in gynaecology -- has received an appropriate basis by development of intrauterine ultrasound, because on the one hand sonographic probe and afterloading probe produce the same geometric circumstances and on the other intrauterine ultrasound has proved to be a method for showing normal myometrium and detecting its pathologic modified regions, especially for localisation and infiltration depth of malignant processes. After computer assisted segmentation and reconstruction of organ slices in three dimensional domain various dose distributions are calculated in case of carcinoma of the body of the uterus. They are produced by various probes and times, during which the radioactive source stops. Using a system of decision rules, a therapy plan is selected, which is an optimum adaptation to the individual geometric circumstances.
INTEGRATING HEALTH INFORMATION MANAGEMENT SYSTEMS
Authors: The American Society for Information Science, Special Intere
Published: January 2007

Integration is a key to the effective management and use of medical information. Academic health sciences centers have recognized this and responded with IAIMS (Integrated Academic Information Management System) programs. Other health care providers, planners, and users need access to the full spectrum of available information to maximize effective patient care and assist consumers in making rational, informed decisions about personal health and health care. Our speakers will discuss the whys and ways of integrating medical information services and systems, and how these systems have been implemented and used in their organizations.
NAOMI one
Authors: Braham Stephen P.
Published: January 2007

The North American OpenMath Initiative (NAOMI) is a recently formed organization to promote, develop, and implement the OpenMath standard in North America. NAOMI held its first workshop in Vancouver this February, and launched full-scale operations.
Completeness of a rewrite system for proving geometric theorems using Clifford algebra
Authors: Fèvre Stéphane
Published: January 2007

In a coordinate-free method proposed by D. Wang and the author for proving geometric theorems, the computations are achieved using an equational theory for Clifford algebra and rewriting techniques. In this note we prove the termination, confluence and completeness of the underlying rewrite system.
On the greatest common right divisor of Ore polynomials with polynomial coefficients which depend on a parameter
Authors: Glotov Peter E.
Published: January 2007

The problem of search for the dependence of GCD of algebraic parametrized objects on a parameter appears in some algorithms of computer algebra. In the case of usual polynomials such problem appears in solving systems of algebraic equations by the elimination method and in some others described in [1]. In the case of rings of polynomials which describe the rings of differential and difference operators such problem appears in solving differential equations in the terms of sparse power series [2]. So it makes interesting to consider this problem from the point of view of Ore polynomial rings which generalize the examples above. For the search for the GCRD of two Ore polynomials it was developed the fast modular algoritm [4]. If we need to determine the depedence of the GCRD on a parameter the next algorithm can be applied: find all the values of a parameter for which the resultant is zero and find the set of GCRDs of polynomials with substituting the parameter by such values. Here we present more efficient non-modular algorithm based on subresultant theory of Ore polynomials [4] which allows to determine the dependence of GCRD on a parameter.
Domain analysis and framework-based software development
Authors: Valerio Andrea , Succi Giancarlo , Fenaroli Massimo
Published: January 2007

Domain Analysis is the process that identifies the relevant objects of an application domain. The goal of Domain Analysis is Software Reuse. The higher is the level of the life-cycle object to reuse, the larger are the benefits coming from its reuse, the harder is the definition of a workable process. Frameworks are excellent candidates for Domain Analysis: they are at a higher level than code but average programmers can understand them.This paper presents the main features of Sherlock, a domain analysis process for the extraction of reusable frameworks, and discusses the impact that Sherlock has on the software process, in particular concerning reuse practices. Sherlock is based on both FODA and Proteus domain analysis techniques. The input of Sherlock is an informal description of the domain based on other domain applications, literature, user requirements, and interviews with domain experts. The output of Sherlock is a set of architectural models (the domain frameworks and patterns), taxonomies of permanencies and variabilities, objects models focusing on the common domain objects. The introduction of Sherlock in the software process requires the definition of new roles and has a valuable impact on reuse practices. We present in this paper a case study: the application of Sherlock at Thera S.p.A., a software company located in Brescia, Italy.
From process modeling to domain modeling
Authors: Benedicenti Luigi , Succi Giancarlo , Vernazza Tullio
Published: January 2007

The hype on software process and software reuse as the capitalization on software as a valuable asset is encountering more and more appreciation. This paper presents an experience in modeling and extracting valuable process assets to build a framework in a small Italian firms specialized in telecommunications personalized solutions.The company has been modeled at first by means of interviews and then analyzing the components in terms of fours main entities.Then, domain analysis was performed. The results of the two phases gave birth to a set of organizational patterns of reuse in the firm that lead to a general organizational framework. The framework can then be refined in a more specific meta-pattern definition or a design framework.
Transformation between different levels of workload characterization for capacity planning: fundamentals and case study
Authors: Graf Ingrid M.
Published: January 2007

Queueing network models are effective tools for capacity planning of computer systems. The base of all performance oriented questions is the characterization of the computer system workload. At the capacity planning level the workload is described in user-oriented terms. At the system level the queueing network model requires input parameters, which differ from the workload description at the capacity planning level. In this paper a general procedure to transform the parameters between these two levels is presented and applied to a case study. The effect on system performance of an increase in the use of an existing application system is analysed.
Network measurement of the VMTP request-response protocol in the V distributed system
Authors: Cheriton david R. , Williamson Carey L.
Published: January 2007

Communication systems are undergoing a change in use from stream to request-response or
transaction
communication. In addition, communication systems are becoming increasingly based on high-speed, low delay, low error rate channels. These changes call for a new generation of networks, network interfaces, and transport protocol design. The performance characteristics of request-response protocols on these high-performance networks should guide the design of this new generation, yet relatively little data of this nature is available.

In this paper, we present some preliminary measurements of network traffic for a cluster of workstations connected by Ethernet running the V distributed operating system. We claim that this system, with its use of a high-speed local area network and a request-response transport protocol tuned for RPC, provides some indication of the performance characteristics for systems in the next generation of communication systems. In particular, these measurements provide an indication of network traffic patterns, usage characteristics for request-response protocols, and the behavior of the request-response protocol itself. These measurements suggest in general that a key design focus must be on minimizing network latency and that a request-response protocol is well-suited for this goal. This focus has implications for protocol design and implementation as well as for the design of networks and network interfaces.
Some conjectures on the behavior of acknowledgement-based transmission control of random access communication channels
Authors: Shenker Scott
Published: January 2007

A class of acknowledgment-based transmission control algorithms is considered. In the finite population case, we claim that algorithms based on backoff functions which increase faster than linearly but slower than exponentially are stable up to full channel capacity, whereas sublinear, exponential, and superexponential algorithms are not. In addition, comments are made about the nature of the quasistationary behavior in the infinite population case, and about how systems interpolate between the finite and infinite number of station cases. The treatment presented here is nonrigorous, consisting of approximate analytic arguments confirmed by detailed numerical simulations.
Do a quick conversion
Authors: Amsler Ann
Published: January 2007

As using the World Wide Web becomes the norm on many university and college campuses, many writers and web designers are being instructed to move most, if not all, documentation to the web. Often, they are expected to simply use an HTML converter to create web documents that are exact replicas of paper documents.This paper examines the implications, particularly for the user, when documents designed for paper are reproduced as-is online. It looks at whether all information is appropriate for the web and at how web pages differ from printed pages. It discusses some of the short comings of converted documents and, finally, offers suggestions for using a converted document as a starting place for producing a worthwhile web document.
Book review: Mind Design II Philosophy, Psychology, and Artificial Intelligence John Haugeland, editor (A 5radford Book The MIT Press Cambridge, MA, 1997 476 pp. ISBN 0-262-58t53-1 (paper) $t9.50 tSBN 0-262-08259-4 (cloth) $40.00)
Authors: Akman Varol
Published: January 2007

John Haugeland, professor of philosophy at the University of Pittsburgh, is well known in the Artificial Intelligence community. With interests --- among others --- in the philosophy of mind and philosophical psychology, he has produced numerous thoughtful works in the past and continues to do so. The title under review,Mind Design II,is the revised version of his 1981 bookMind Design.Other Haugeland books includeArtificial Intelligence: The Very Idea[Haugeland 1985] andHaving Thought[Haugeland 1997].
Book review: Constraint-Based Reasoning by E.C. Freuder and A.K. Mackworth (Eds.) (The MIT Press Cambridge, MA, 1994 )
Authors: Bielikova Maria
Published: January 2007

This book is reprinted from
Artificial Intelligence: An International Journal,
Volume 58, Numbers 1--3, 1992. There are reported new results in constraint-based reasoning. Constraint-based reasoning has a long tradition in artificial intelligence. Many problems to which artificial intelligence techniques are often applied can be described as constraint satisfaction problems.
Hypertext information retrieval for the Web
Authors: Brown Eric W. , Smeaton Alan F.
Published: January 2007

The notion of searching a hypertext corpus has been around for some time, and is an especially important topic given the growth of the World Wide Web and the general dissatisfaction users have with the tools currently available for finding information on the Web. In response to this, a workshop was held as part of SIGIR'98 on
Hypertext Information Retrieval for the Web
and this document presents a brief summary of the papers presented at that workshop, along with a set of themes identified as a result of group discussion and some conclusions on where to go next.
New challenges for Fortran in the next millennium
Authors: Hey Tony
Published: January 2007

This paper discusses the economics of program optimisation and some of the challenges facing the parallel Fortran community. Industry takes a much broader view of cost optimisation than just speeding up a Fortran application code. Two examples of industrial "Fortran" projects undertaken by the Parallel Applications Centre (PAC) at Southampton are used to illustrate these industrial concerns. The PROMENVIR project demonstrated cost-effective use of a Europe-wide metacomputer, composed of idle workstations and parallel systems connected by a WAN, to explore the design space of an industrial application. By contrast, the TOOLSHED project was concerned with integration of the design and grid generation phase with the simulation phase of the industrial design cycle. The paper concludes with a discussion of three important challenges for the continued health of parallel Fortran community. These are: the multiplicity of versions of parallel Fortran; competition from high-level scientific packages such as AXIOM, MATLAB and Mathematica; and finally, the inexorable rise in popularity of Java-based, network-centric computing.
Evolution and evaluation of SPEC benchmarks
Authors: Dujmovic Jozo J. , Dujmovic Ivo
Published: January 2007

We present a method for quantitative evaluation of SPEC benchmarks. The method is used for the analysis of three generations of SPEC component-level benchmarks: SPEC89, SPEC92, and SPEC95. Our approach is suitable for studying (1) the redundancy between individual benchmark programs, (2) the size, completeness, density and granularity of benchmark suites, (3) the distribution of benchmark programs in a program space, and (4) benchmark suite design and evolution strategies. The presented method can be used for designing a universal benchmark suite as the next generation of SPEC benchmarks.
Selection algorithms for replicated Web servers
Authors: Sayal Mehmet , Breitbart Yuri , Scheuermann Peter , Vingralek Radek
Published: January 2007

Replication of documents on geographically distributed servers can improve both performance and reliability of the Web service. Server selection algorithms allow Web clients to select one of the replicated servers which is "close" to them and thereby minimize the response time of the Web service. Using client proxy server traces, we compare the effectiveness of several "proximity" metrics including the number of hops between the client and server, the ping round trip time and the HTTP request latency. Based on this analysis, we design two new algorithms for selection of replicated servers and compare their performance against other existing algorithms. We show that the new server selection algorithms improve the performance of other existing algorithms on the average by 55%. In addition, the new algorithms improve the performance of the existing non-replicated Web servers on average by 69%.
Transfer of learning
Authors: Tetzlaff Linda
Published: January 2007

An experiment on transfer of learning using text editors revealed significant differences in performance, based on the learning experience of the subjects. The set of commands of a text editor was divided into four subsets. Different groups of subjects learned these subsets in different orders. Depending on the order of learning, subjects formed different concepts of the editor as manifest by their choice of commands, their errors, and their model of the editor, elicited by a sorting task. Pragmatic production model approaches to transfer would need significant enhancement to accommodate this result.
Specifying complex dialogs in ALGAE
Authors: Flecchia Mark A. , Bergeron R. Daniel
Published: January 2007

The complexity and high development costs of user interfaces has led to research into the design of User Interface Management Systems (UIMSs). At the heart of a UIMS is a facility for specifying a dialog control component, which processes user actions and coordinates program responses. This paper describes a language called ALGAE, which allows the specification of multi-threaded, event driven dialogs.
Intelligence in interfaces (panel)
Authors: Neches Robert , Brown John Seely , Sondheimer Norm , Malone Tom , Williams Mike
Published: January 2007

The purpose of this symposium is three-fold:

First, by presenting a selection of our work as examples, we seek to define a model of intelligent interaction and illustrate points in the interface process where artificial intelligence can play a role.

Second, by comparing the approaches represented in our efforts, we intend to explore a fundamental philosophical difference in the field of intelligent interfaces: the distinction between the
power tools
vs. the
intelligent assistant
paradigms. (As part of this discussion, we intend to consider how to mine the rich ground that lies between these two extremes.)

Third, by examining the design process underlying our examples, we seek to provide a better understanding of the relationship between AI interface tools and the applications that they communicate with.
Panther
Authors: Helfman J. I.
Published: January 2007

An experimental graphical control specification system, called Panther, has been written in C for UNIX®-based applications. Unlike similar systems, which focus on combining interaction techniques, Panther allows the specification of low-level interactions by invoking user-selectable subroutines for input-device transitions. A Panther interface is specified in a textual table as a set of hierarchically nested
regions
. Regions can model any control device, such as menu buttons, slider-bars, switches, alphanumeric displays, or even combinations of other regions. Panther does not rely on special hardware, extensive software, or interprocess communication.
The use of scenarios in human-computer interaction research
Authors: Young Richard M. , Barnard Phil
Published: January 2007

A scenario is an idealised but detailed description of a specific instance of human-computer interaction (HCI). A set of scenarios can be used as a “filter bank” to weed out theories whose scope is too narrow for them to apply to many real HCI situations. By helping redress the balance between generality and accuracy in theories derived from cognitive psychology, this use of scenarios (1) allows the researcher to build on empirical findings already established while avoiding the tar-pits associated with the experimental methodology, (2) enables the researcher to consider a range of phenomena in a single study, thereby directly addressing the question of the scope of the theory, and (3) ensures that the resulting theory will be applicable in HCI contexts.
Approximate modelling of cognitive activity: towards an expert system design aid
Authors: Barnard Phil , Wilson Michael , MacLean Allan
Published: January 2007

Constructs from theoretical psychology can be used to decompose the representational and processing resources of cognition. The decomposition supports “cognitive task analysis” through which user performance can be related to the functioning of resources. Such functional relationships have been formalised and embodied in an expert system. This builds approximate models which describe cognitive activity associated with the execution of dialogue tasks. Attributes of these “cognitive task models” can be used to predict likely properties of user performance.
A multiple, virtual-workspace interface to support user task switching
Authors: Card Stuart K. , Henderson Austin
Published: January 2007

An interface is presented that is designed to help users switch among tasks on which they are concurrently working. Nine desirable properties for such an interface are derived. It is argued that a key constraint to building interfaces that support task switching is that low user-overhead switching among tasks requires a large amount of display space, whereas actual display space is limited. A virtual workspace design is presented that greatly speeds the inevitable task-switching induced window faulting. The resulting interface is presented as a study in theory-based human-interface design. It is shown how in this case theory is important in inspiring a design, but design entailments outside the theory raise new issues that must be faced to make the design viable. These design experiences, in turn, help inspire new theory.
Experiences with parallel job scheduling on a transputer system
Authors: Chan Yuet-Ning , Dandamudi Sivarama P. , Majumdar Shikharesh
Published: January 2007

Both time and space sharing strategies have been proposed for job scheduling in multiprogrammed parallel systems. This paper summarizes the major observations gained from an experimental investigation of these two partition sharing strategies on a Transputer system. A number of factors such as the applications and their software architectures in the multiprogramming mix, the partition sharing strategy, and the partition size are varied and the resulting insights into system performance and scheduling are presented. Space sharing is observed to produce a superior performance in comparison to time sharing for a number of multiprogrammed workloads. Time sharing showed a better performance for workloads with high variability in process execution times, and with high rates of interprocess communication. The relationships between system performance and a number of workload and system characteristics are presented.
Factors affecting professional competence of information technology professionals
Authors: Blanton J. Ellis , Schambach Thomas , Trimmer Kenneth J.
Published: January 2007

Design and development of effective information technology (IT) based systems depends upon a staff of competent information technology professionals (ITPs). Due to the rapid pace of technological innovation, diverging application of IT, and changing role responsibilities of ITPs, it is becoming increasingly difficult for ITPs to maintain up-to-date professional competency.Although not extensively examined in IT research, professional obsolescence threats have been acknowledged and evaluated in referent research. Psychologists studying the engineering discipline have suggested individual characteristics, nature of work, and organizational climate as being important determinants of obsolescence.The purpose of this study was to evaluate the relationships between individual personality differences and manageable work context factors and the degree of professional competency, or conversely obsolescence of ITPs. Structural equation modeling was employed in evaluating the direct-effects model of professional competency. The study used questionnaires to obtain 161 usable self-report responses from systems analysts. The results suggest that individual personality differences and factors of the work environment do effect professional competency levels. Overall, the research model accounted for 44% of the variance in ITP competency.
Critical success factors for IS executive careers—evidence from case studies
Authors: Shi Nansi , Bennett David
Published: January 2007

This article qualitatively analyzes the Critical Success Factors (CSFs) for Information Systems (IS) executive careers based on evidence gathered from five case studies carried out in 1997. Typical IS executive career paths are presented within a time series style and the CSFs are interpreted within a descriptive framework by synthesising the case data based on Social Cognitive Theory. The descriptive framework suggests that successful IS executive careers would most likely be achieved by well educated and experienced IS employees who have the right attitude towards both their career and work, together with good performance. They would also exhibit an ability for self-learning and to anticipate future IT uses, as well as having proficient IS management knowledge and skills while working with an appropriate organizational environment. Moreover, the framework systematically indicates the interactions between the coupling factors in the typical career development processes. This provides a benchmark for employees that are aiming at a senior IS executive career against which they can compare their own achievements and aspirations. It also raises propositions for further research on theory building.
Data transfer between Java Applets and legacy APL systems
Authors: Amos B. , Disney G. , Sorrey D.
Published: January 2007

The rise of Internet technologies (particularly Java) provides many benefits for the development and deployment of user interfaces. In many cases, however, the back end system is behind the times: Internet hostile, no object orientation, etc. How can data be transferred between the new generation front end and the old generation back end without compromising the strengths or integrity of either? This paper discusses the use of customised Java data serialisation to achieve this goal against a large IBM MVS Sharp APL system.
The computer construction of weaving designs
Authors: Smillie Keith
Published: January 2007

Weaving is the art of forming a fabric by interlacing threads at right angles and is performed on a frame called a loom. The threads at right angles to the weaver are the warp threads, and the threads parallel to the weaver and which are inserted between the warp threads are the weft threads. The warp threads are alternately raised and lowered to create a shed through which the weft thread is inserted. They are fastened to a warp roller at the back of the loom, pass over a back beam and through the eyes of vertical wires called heddles, and then through reeds which help keep them parallel and in the proper sequence. The woven cloth passes over a front beam and is then wound onto a cloth roller. Each row of heddles is attached to a harness, and there may be two, four, eight or more harnesses. Each warp thread passes through a heddle on any one of the harnesses. The harnesses are raised and lowered by treadles which are worked by the fingers on a table loom and by the feet on a foot loom. Harnesses may be tied together so that more than one may be operated by the same treadle. As a group of warp threads is raised or lowered by the treddles, the shuttle with the weft thread is inserted into the shed between the two groups of threads.
Interactive design of structures
Authors: Riebenbauer Johann , Hoffmann Joachim
Published: January 2007

In this paper we present a program for the design and analysis of planar member frame structures. The intuitive graphic user interface covers all steps necessary for designing a load bearing structure, from geometry design to system optimization.This project is the first step in converting from a pool of APL*PLUS II programs towards interactive Windows applications written in DyalogAPL/W, and was carried out by Dipl.-Ing. Johann Riebenbauer, Institute of Structural Design (Institut für Tragwerkslehre) at the Technical University of Graz, Austria, and the Group of Civil Engineering (IG für Bauwesen) Zenkner&Handel.The computational section of the described application is composed of proven space frame algorithms, which where developed by Prof. Peter Klement over the last three decades in APL, and which represent the backbone of the new graphic user interface (GUI) in DyalogAPL/W. (In the Appendix the reader can find a small vocabulary, which can be used to translate the German words in the illustrations.)
Footprints in the cache
Authors: Stone Harold S. , Thibaut Dominique
Published: January 2007

This paper develops an analytical model for a cache-reload transient. When an interrupt program or system program runs periodically in a cache-based computer, a short cache-reload transient occurs each time the interrupt program is invoked. That transient depends on the size of the cache, the fraction of the cache used by the interrupt program, and the fraction of the cache used by background programs that run between interrupts. We call the portion of a cache used by a program its
footprint
in the cache, and we show that the reload transient is related to the area in the tail of a normal distribution whose mean is a function of the footprints of the programs that compete for the cache. We believe that the model may be useful as well for predicting paging behavior in virtual-memory systems with round-robin scheduling.
The analysis and performance of batching arbiters
Authors: Kleeman Lindsay , Cantoni Antonio
Published: January 2007

A class of arbiters, known as batching arbiters, is introduced and defined. A particularly simple decentralised example of a batching arbiter is described, with motivation given for the batching arbiter model adopted. It is shown that under reasonable assumptions, batching arbiters can be described by a finite state Markov chain. The key steps in the analysis of the arbiter performance are the method of assigning states, evaluation of state transition probabilities and showing that the Markov chain is irreducible. Arbiter performance parameters are defined, such as proportion of time allocated to each requester and mean waiting time for each requester. Apart from results describing the steady state behavior of the arbiter for general system parameters, a number of limiting results are also obtained corresponding to light and heavy request loading.

Finally, numerical results of practical interest are presented, showing the performance parameters of the arbiter versus request rates for various configurations.
Performance analysis of an algorithm for concurrency control in replicated database systems
Authors: Swinghal Mukesh , Agrawala A. K.
Published: January 2007

In this paper, we analyze the performance of a concurrency control algorithm for replicated database systems. We present a model of a distributed database system which provides a framework to study the performance of different concurrency control algorithms. We discuss performance criteria to evaluate different algorithms. We use the model to analyze the performance of an algorithm for concurrency control in replicated database systems. The technique used in analysis is iterative and approximate. We plot a set of performance measures for several values of the model parameters. The results of analysis are compared against a simulation study.
Analysis of a conveyor queue in a flexible manufacturing system
Authors: Coffman E. G. , Gelenbe E. , Gilbert E. N.
Published: January 2007

In a flexible manufacturing system stations are arranged along a common conveyor that brings items for processing to the stations and also carries away the processed items. At each station specialized robots automatically load and unload items on and off the conveyor. We examine here a single station in such a system. A new kind of queueing problem arises, with input-output dependencies that result because the same conveyor transports items both to and from the station. The paper analyzes two models of a station. Model 1 has one robot that cannot return a processed item to the conveyor while unloading a new item for processing. Model 2 has two robots to allow simultaneous loading and unloading of the conveyor. A principal goal of the analysis is the proper choice of the distance separating the two points at which items leave and rejoin the conveyor.
Analytic performance model of the U.S. en route air traffic control computer systems
Authors: Bleistein Sandra , Cho Shin-Sun , Goettge Robert T.
Published: January 2007

An analytic performance modeling case study of a complex command and control computer system is presented. A queueing network model of the system was developed and validated. Features of the model found to be critical to its accuracy were detailed software models, general service time distributions, and models of transient response time behavior. Response time prediction accuracy of the model was validated to 20 percent for moderate device utilizations. The study shows that analytic techniques can be successfully applied to performance modeling of complex systems. Prediction of response time percentile values and modeling of transient effects are identified as two areas where improved analytic techniques would enhance performance engineering of such systems.
Multiclass queueing networks with population constrainted subnetworks
Authors: Krzesinski A. E. , Teunissen P.
Published: January 2007

A Multiclass Queueing Network model (MQN) is partitioned into a set of disjoint subnetworks. Population constraints are applied to each subnetwork such that within each subnetwork each population chain is either subject to an individual population constraint, or a group of chains may be subject to a common (shared) population constraint. Such population constraints are necessary in order to model multiprogramming level constraints in mainframe computer systems and window flow control mechanisms in computer communication networks. A computationally efficient approximate solution method is developed for solving MQN's with population constraints. Each subnetwork is reduced to a single approximately flow equivalent composite centre by assuming that the effect of other chains on a given chain can be adequately represented by their average customer populations. The accuracy of the population constraint approximation is compared against previous techniques by applying it to a set of test cases for which simulation solutions have previously been reported. The accuracy of the approximation technique is found to be good and in general is an improvement over previously published concurrency constraint approximations.
Evaluation of optical disk systems for very large database applications
Authors: Hevner Alan R.
Published: January 2007

Optical Disk Systems have significant advantages over conventional magnetic mass storage media for very large database applications. Among other features, optical disk systems offer large capacity and high transfer rate. A critical problem is how to integrate the optical disk system into a total application system environment while maintaining the high performance capabilities of the optical disk. In this paper the performance of optical disk system configurations under realistic application environments is analyzed via queueing models. The results provide several important guidelines for the use of optical disk systems on large applications.
Analysis of some optimistic concurrency control schemes based on certification
Authors: Thomasian Alexander , Ryu In Kyung
Published: January 2007

Optimistic Concurrency Control-OCC schemes based on certification are analyzed in this paper. We allow two types of data access schemes referred to as static and dynamic. According to the first (second) scheme a transaction reads all the required data items at the beginning of its processing (on demand during its processing), respectively. After completing its processing, each transaction is checked as to whether it has encountered a data conflict. Validated transactions commit; otherwise, they are restarted. A variant of the regular (silent) commit scheme where a committing transaction notifies conflicted transactions to restart immediately (broadcast commit scheme) is also considered. We use an iterative method to analyze the performance of OCC schemes in the framework of a system with a fixed number of transactions in multiple classes with given probabilities for their occurrence. The iterative method is validated against simulation and shown to be highly accurate even for high data contention. We present graphs/tables, which are used to determine how system performance is affected by: (i) various OCC schemes, (ii) transaction size, i.e., number of data items accessed, (iii) number of transactions, (iv) the distribution of transaction processing time requirements, (v) the throughput characteristic of the system, and (vi) granule placement.
Writing optimization software in APL, J, and MATLAB
Authors: Brown Richard L. W.
Published: January 2007

Since the appearance of [Karmarkar 1984], interior point methods for linear programming have developed sufficiently to challenge the traditional simplex method, especially on large problems. Moreover, interior point methods generalize to certain types of nonlinear problems that cannot be handled by the simplex method [Ye 1997].A search of the Internet will reveal a number of software packages that implement interior point methods for linear and nonlinear problems (For example, see [Helmberg 1998, Wolkowicz 1998]). The programming languages used include FORTRAN, C, PASCAL, and (most frequently) MATLAB.Examination of these codes shows that they involve extensive manipulation of arrays of numbers. Some MATLAB codes use arrays of dimension greater than two and arrays whose elements are arrays. Higher dimensional and nested arrays are a recent addition to MATLAB (added in Version 5, the current version) but have been available in APL and J for some time.Why is the array processing language MATLAB such a popular choice rather than APL or J? Is this an area where APL and J can make a contribution?To gain insight into these questions, we compare interior point method code written in MATLAB to code written in APL and J.
All searches are divided into three parts
Authors: Siegel David E.
Published: January 2007

This paper considers the problem of searching for strings in a dictionary or symbol table. It presents a data structure which can be used for this purpose---the Ternary Tree. It considers the theoretical properties of this structure, compared with other possible structures for the same purpose. It presents an implementation of this structure in APL, including code to do a variety of operations on it.
Pattern recognition in APL with application to reactor diagnostics
Authors: Skomorokhov Alexander O. , Slepov Michail T.
Published: January 2007

The paper describes implementation in APL of some methods of pattern recognition. These general-purpose techniques of data analysis are illustrated by application to Nuclear Power Plant Diagnostics. In particular we consider vibration spectra analysis, including simple descriptive statistics, smoothing and peak extractions, multidimensional scaling for data visualization, informative features selection, cluster analysis and classification.Implementation of algorithms used in the paper has been done in Dyalog APL. The paper discusses benefits of using APL for the problem area.Application is based on analysis of real vibration characteristics measured at the Nuclear Power Plant in Novovoronehz. The paper discusses the technology of the analysis, the discovered data structure, and malfunction diagnostics.The paper also mentions using the implemented techniques in the training of engineers for Nuclear Power plant and other applications.
An empirical study on how program layout affects cache miss rates
Authors: Bradford Jeffrey P. , Quong Russell
Published: January 2007

Cache miss rates are quoted for a specific program, cache configuration, and input set; the effect of program layout on the miss rate has largely been ignored. This paper examines the
miss variation,
that is, the variation in the miss rate for instruction and data caches resulting from randomly generated layouts; the layouts were generated by changing the order of the modules on the command line when linking. This analysis is performed for several cache sizes, lines sizes, set-associativities, input sets, compiler versions, and optimization levels for five programs in the SPEC92 benchmark suite. Miss rates were observed that varied from 60% to 180% of the mean miss rate. We did not observe any consistently good layouts across different parameters; in contrast, several layouts were consistently bad. Overall, cache line size and input set has little effect on the miss variation, while increasing the cache size (i.e. decreasing the miss rate), decreasing the set-associativity, or increasing the optimization level increases the miss variation. For a direct-mapped cache, the results in this paper call into question the validity of using a single layout (
i
) to determine the miss rate of a given program, (
ii
) to determine how a given compiler optimization affects the miss rate, and (
iii
) to make architecture design decisions based on the miss rate.
On achievable service differentiation with token bucket marking for TCP
Authors: Sahu Sambit , Nain Philippe , Diot Christophe , Firoiu Victor , Towsley Don
Published: January 2007

The Differentiated services (diffserv) architecture has been proposed as a scalable solution for providing service differentiation among flows without any per-flow buffer management inside the core of the network. It has been advocated that it is feasible to provide service differentiation among a set of flows by choosing an appropriate “marking profile” for each flow. In this paper, we examine (i) whether it is possible to provide service differentiation among a set of TCP flows by choosing appropriate marking profiles for each flow, (ii) under what circumstances, the marking profiles are able to influence the service that a TCP flow receives, and, (iii) how to choose a correct profile to achieve a given service level. We derive a simple, and yet accurate, analytical model for determining the achieved rate of a TCP flow when edge-routers use “token bucket” packet marking and core-routers use active queue management for preferential packet dropping. From our study, we observe three important results: (i) the achieved rate is not proportional to the assured rate, (ii) it is not always possible to achieve the assured rate and, (iii) there exist ranges of values of the achieved rate for which token bucket parameters have no influence. We find that it is not easy to regulate the service level achieved by a TCP flow by solely setting the profile parameters. In addition, we derive conditions that determine when the bucket size influences the achieved rate, and rates that can be achieved and those that cannot. Our study provides insight for choosing appropriate token bucket parameters for the achievable rates.
Comparing random data allocation and data striping in multimedia servers
Authors: Santos Jose Renato , Muntz Richard R. , Ribeiro-Neto Berthier
Published: January 2007

We compare performance of a multimedia storage server based on a random data allocation layout and block replication with traditional data striping techniques. Data striping techniques in multimedia servers are often designed for restricted workloads, e.g. sequential access patterns with CBR (constant bit rate) requirements. On the other hand, a system based on random data allocation can support virtually any type of multimedia application, including VBR (variable bit rate) video or audio, and interactive applications with unpredictable access patterns, such as 3D interactive virtual worlds, interactive scientific visualizations, etc. Surprisingly, our results show that system performance with random data allocation is competitive and sometimes even outperforms traditional data striping techniques, for the workloads for which data striping is designed to work best; i.e. streams with sequential access patterns and CBR requirements. Due to its superiority in supporting general workloads and competitive system performance, we believe that random data allocation will be the scheme of choice for next generation multimedia servers.
RESCU
Authors: Joshi Srinath R. , Rhee Injong
Published: January 2007

The current Internet is not reliable; packet loss rates are frequently high, and varying over time. Transmitting high-quality interactive video over the Internet is challenging because the quality of compressed video is very susceptible to packet losses. Loss of packets belonging to a video frame manifests itself not only in the reduced quality of that frame but also in the propagation of that distortion to successive frames. This error propagation problem is inherent in many motion-based video codecs due to the interdependence of encoded video frames. This paper presents a dynamic loss recovery scheme, called RESCU, to address the error propagation problem. In this new scheme, picture coding patterns are
dynamically
adapted to current network conditions in order to maximize the effectiveness of hybrid transport level recovery (employing both forward error correction and retransmission) in reducing error propagation. Since RESCU does not introduce any playout delay at the receiver, it is suitable for interactive video communication. An experimental study based on actual Internet transmission traces representing various network conditions shows that dynamic hybrid RESCU exhibits better error resilience and incurs much less bit overhead than existing error recovery techniques such as NEWPRED and Intra-H.261.
AMVA techniques for high service time variability
Authors: Eager Derek L. , Sorin Daniel J. , Vernon Mary K.
Published: January 2007

Motivated by experience gained during the validation of a recent Approximate Mean Value Analysis (AMVA) model of modern shared memory architectures, this paper re-examines the “standard” AMVA approximation for non-exponential FCFS queues. We find that this approximation is often inaccurate for FCFS queues with high service time variability. For such queues, we propose and evaluate: (1) AMVA estimates of the mean residual service time at an arrival instant that are much more accurate than the standard AMVA estimate, (2) a new AMVA technique that provides a much more accurate estimate of mean center residence time than the standard AMVA estimate, and (3) a new AMVA technique for computing the mean residence time at a “downstream” queue which has a more bursty arrival process than is assumed in the standard AMVA equations. Together, these new techniques increase the range of applications to which AMVA may be fruitfully applied, so that for example, the memory system architecture of shared memory systems with complex modern processors can be analyzed with these computationally efficient methods.