bluuebunny/crossref_metadata_2025 huggingface dataset:
Designing in the dark: logics that compete with the user
Authors: Grudin J.
Published: January 2007

Skills developed by software user interface designers to solve problems in communication, management, implementation, and other areas may influence design decisions in the absence of sufficient knowledge of user populations. Given today's rapid change in both “faces” to the software interface — user populations and software functionality — the first pass at a design may be made without sufficient understanding of the relevant goals and behaviors of the eventual users. Without this information, designers are less able to grasp “user logic”, and may rely on more familiar “logics” that are useful in other problem-solving arenas. Understanding how these approaches can affect a design may help us recognize them across a wide range of contexts and enable us to focus the human factors contribution to the design evolution process.
Network traffic measurement and modeling
Authors: Williamson Carey L.
Published: January 2007

Network traffic measurement and workload characterization are key steps in the workload modeling process. Much has been learned through network measurement and workload modeling in the last ten years, but new challenges are now at the forefront: measuring network traffic in the Internet environment, understanding the implications of network traffic structure (e.g., self-similarity, autocorrelation, long range dependence), and accurate modeling of network traffic workloads for high speed network environments.This "hot topic" session brings together three prominent speakers to address each of these topics, in turn.
Data interpretation and experiment planning in performance tools
Authors: Malony Allen D.
Published: January 2007

The parallel scientific computing community is placing increasing emphasis on portability and scalability of programs, languages, and architectures. This creates new challenges for developers of parallel performance analysis tools, who will have to deal with increasing volumes of performance data drawn from diverse platforms. One way to meet this challenge is to incorporate sophisticated facilities for data interpretation and experiment planning within the tools themselves, giving them increased flexibility and autonomy in gathering and selecting performance data. This panel discussion brings together four research groups that have made advances in this direction.
Scheduling memory constrained jobs on distributed memory parallel computers
Authors: McCann Cathy , Zahorjan John
Published: January 2007

We consider the problem of multiprocessor scheduling of jobs whose memory requirements place lower bounds on the fraction of the machine required in order to execute. We address three primary questions in this work:1. How can a parallel machine be multiprogrammed with minimal overhead when jobs have minimum memory requirements?2. To what extent does the inability of an application to repartition its workload during runtime affect the choice of processor allocation policy?3. How rigid should the system be in attempting to provide equal resource allocation to each runnable job in order to minimize average response time?This work is applicable both to parallel machines and to networks of workstations supporting parallel applications.
Active memory
Authors: Lebeck Alvin R. , Wood David A.
Published: January 2007

This paper describes the
active memory
abstraction for memory-system simulation. In this abstraction---designed specifically for on-the-fly simulation, memory references logically invoke a user-specified function depending upon the reference's type and accessed memory block state. Active memory allows simulator writers to specify the appropriate action on each reference, including "no action" for the common case of cache hits. Because the abstraction hides implementation details, implementations can be carefully tuned for particular platforms, permitting much more efficient on-the-fly simulation than the traditional trace-driven abstraction.Our SPARC implementation,
Fast-Cache,
executes simple data cache simulations two or three times faster than a highly-tuned trace-driven simulator and only 2 to 7 times slower than the original program. Fast-Cache implements active memory by performing a fast table look up of the memory block state, taking as few as 3 cycles on a SuperSPARC for the no-action case. Modeling the effects of Fast-Cache's additional lookup instructions qualitatively shows that Fast-Cache is likely to be the most efficient simulator for miss ratios between 3% and 40%.
The interaction of parallel and sequential workloads on a network of workstations
Authors: Arpaci Remzi H. , Dusseau Andrea C. , Vahdat Amin M. , Liu Lok T. , Anderson Thomas E. , Patterson David A.
Published: January 2007

This paper examines the plausibility of using a network of workstations (NOW) for a mixture of parallel and sequential jobs. Through simulations, our study examines issues that arise when combining these two workloads on a single platform. Starting from a dedicated NOW just for parallel programs, we incrementally relax uniprogramming restrictions until we have a multi-programmed, multi-user NOW for both interactive sequential users and parallel programs. We show that a number of issues associated with the distributed NOW environment (e.g., daemon activity, coscheduling skew) can have a small but noticeable effect on parallel program performance. We also find that efficient migration to idle workstations is necessary to maintain acceptable parallel application performance. Furthermore, we present a methodology for deriving an optimal delay time for recruiting idle machines for use by parallel programs; this
recruitment threshold
was just 3 minutes for the research cluster we measured. Finally, we quantify the effects of the additional parallel load upon interactive users by keeping track of the potential number of
user delays
in our simulations. When we limit the maximum number of delays per user, we can still maintain acceptable parallel program performance. In summary, we find that for our workloads a 2:1 rule applies: a NOW cluster of approximately 60 machines can sustain a 32-node parallel workload in addition to the sequential load placed upon it by interactive users.
G-networks
Authors: Gelenbe Erol
Published: January 2007

This Hot-Topics Session on G-Networks aims at bringing these relatively new models which we introduced for the first time in 1989 and 1990, to the attention of the performance evaluation and modeling community. The session includes presentations by
Peter Harrison, Onno Boxma, Jean-Michel Fourneau
and myself. We will cover the basic concepts, some examples of potential applications, as well as recent research efforts in this area.
Town, gown and the Web
Authors: Yohe J. Michael
Published: January 2007

The World Wide Web (WWW) can be used to help build mutually supportive coalitions between colleges and universities and the larger communities in which they are located. Academic institutions are ideal partners in establishing community information systems, helping foster the use of technology in the primary and secondary schools, and building regional networks of people as well as computers. Members of the larger community, in return, can offer additional breadth and depth of experience and a "real world" perspective on technology.At the same time, these partnerships raise significant management issues, including funding of hardware and network connections; equal access for all citizens; handling concerns about socially unacceptable, unethical, or criminal activity; bandwidth issues; and administering World Wide Web spaces in the community context. We examine these issues and offer suggestions from the point of view of the University of Northern Iowa's involvement with the local metropolitan area and the Iowa Research and Education Network's Rural Datafication and K-12 initiatives.
Cognitive architectures and HCI
Authors: Kirschenbaum Susan S. , Gray Wayne D. , Young Richard M.
Published: January 2007

The Cognitive Architectures and Human-Computer Interaction Workshop examined computational cognitive modeling approaches to human-computer interaction issues (HCI). The five major architectures and variations represented were briefly summarized. Participants compared approaches to a set of selected HCI problems and alternative solutions, and compared the strengths and weaknesses of the architectures. A list of additional issues was generated and discussed.
The object oriented real-time systems (OORTS) workshop
Authors: van Roosmalen Onno S.
Published: January 2007

The workshop was held in San Antonio Texas in conjunction with the "7th IEEE Symposium on Parallel and Distributed Processing" (SPDP) on October 27th, 1995. It was organized in cooperation with the Software Engineering Laboratory at NJIT with support from the U.S. Naval Surface Warfare Center and the faculty of Mathematics and Computing Science of the Eindhoven University of Technology.
High-level dynamic memory management for object-oriented real-time systems
Authors: Nilsen Kelvin
Published: January 2007

Dynamic memory management in real-time systems is difficult because most traditional allocation and deallocation algorithms are unpredictable in terms of their worst-case memory utilization and execution times. This paper describes recent work on a new memory management system designed specifically to support hard-real-time allocation, automatic garbage collection, and defragmentation of the free pool. The memory management system consists of special hardware circuits placed between the CPU's level-two caches and its memory subsystem. Benefits include worst-case allocation delays of two microseconds and typical memory utilizations that exceed binary-buddy allocators by over 30%. A commercial implementation of this technology is currently under development.
Field oriented design techniques
Authors: Wixon Dennis , Ramey Judy
Published: January 2007

This workshop, held at CHI 95, focused on field research methods that allow us to incorporate a holistic understanding of users and their work and its context into the design process at the earliest stages. Although these techniques hold great promise and have attracted attention and interest in the CHI community, they have not been widely adopted or systematically discussed in the published literature. This workshop was developed to address this deficiency. We were fortunate in receiving a large set of position papers in response to our call for participation; we accepted 12 of about 20 papers submitted (and we both had a case to contribute, for a total of 14 cases).We planned the workshop activities to allow for maximum interaction among the participants. So that we could all arrive already acquainted with each others' studies, we circulated the participants' position papers ahead of time. Our goals for the day-and-a-half workshop (extended by popular demand to include working lunches and extra time on the second day) were to develop a common understanding of the work done in each of the studies, to map the work done in each study to the stages of the design process where it fit best or had the greatest impact, and to come away with a systematic model of the terminology, methodology, and effectiveness of field research as represented in this set of cases. These goals were naturally larger than we could achieve in the short time allotted us, but the enthusiasm and dedication of the group has enabled us to continue to work on them since CHI 95 and will yield a published collection of case studies and essays this Fall.
Reasoning on gestural interfaces through syndetic modelling]
Authors: Faconti G. P.
Published: January 2007

Recent advances in user interface development have been mainly driven by technical innovation, based either on new interaction devices and paradigms, or on algorithms for achieving realistic audio/visual effects [Connor92] [Robertson91a] [Robertson91b] [Berners92]. In such a rich environment, the user potentially interacts with the computer by addressing concurrently different modalities. While the technology driven approach has made possible the implementation of systems in specific application areas, it largely misses an undelying theory. This makes it difficult to assess whether this technology will be effective for users with the consequence that cognitive ergonomics is becoming an urgent requirement for the design of new interactive systems. Attention has been paid to the psychology of terminal users from the very beginning of human-computer interface research [Martin73]. However, existing established design techniques do not readily accomodate issues such as concurrency and parallelism, or the potential for the interaction with multiple interface techniques [Coutaz93].Recently, works have taken place investigating models and techniques for the analysis and design of interactionally rich systems from a variety of disciplinary perspectives as it can be found in the DSV-IS book series edited by [Paterno94] and [Bastide95]. Formal methods have been one of a number of approaches; others include cognitive user models, design space representations, and software architecture models. Applications for formal methods are well known, see for example [Bowen95], and [Gaudel94]. However, none of the cited applications use formal methods to examine the user interface. One reason is that the factors that influence the design of interactive systems depend mostly on psychological and social properties of cognition and work, rather than on abstract mathematical models of programming semantics. For this reason, claims made through formal methods about the properties of interactive systems must be grounded in some psychological or social theory.This paper builds on previous works carried within the ESPRIT Amodeus project and shows how a new approach to human-computer interaction, called
syndetic
modeling, can be used to gain insight into user-oriented properties of interactive systems. The word syndesis comes from the ancient greek and means
conjunction.
It is used to emphasize the key point of this approach: user and system models are described within a common framework that enables one to reason about how cognitive resources are mapped onto the functionality of the system.
Moving tasks at the center of the development, execution and evaluation process
Authors: Paternó Fabio
Published: January 2007

This paper shows how the concept of user task can be used to drive various phases of the design process. The basic idea is to create a direct correspondence between user tasks and the software components needed to perform them. This leads to such results as the design of functionalities which are easier to use, task-oriented help, and the evaluation of users sessions with respect to their tasks.
A tool to support specification and evaluation of context-customized interfaces
Authors: de Rosis Fiorella , Pizzutilo Sebastiano , De Carolis Berardina
Published: January 2007

Intelligent tools to support user interface building are being developed as a response to the difficulty of implementing interfaces of increasing complexity [1, 5, 6, 10, 7]. These tools provide expert assistance to insure that usable interfaces are developed correctly, by formalizing guidelines and criteria which are well known to experts. Less effort has been devoted so far to the objective of supporting the cooperative work of designers and final users in defining how the interface should look like and behave, in evaluating design alternatives and in assessing consequences of changes. This objective becomes relevant when the interface is built in strict cooperation with customers who are not familiar with computers, and by applying iterative design principles. At the same time, it is a common opinion that tools able to support formal evaluation of interfaces might be of help to avoid engaging into expensive empirical evaluations before trivial errors are eliminated from the prototype.A particular specification problem occurs when several categories of users, with distinct backgrounds and needs, are expected to use the system which is being designed: in this case, the interaction style is customized to the context in which the system operates, and the tool should enable simulating and evaluating the different behaviours in a unified way.This paper describes a tool which aims at responding to the mentioned objectives: XDM (Context-Sensitive Dialogue Modeling) extends Coloured Petri Nets to specify context-customized interfaces in a task-based way and to simulate their behaviour in defined contexts. By integrating this modeling approach with KLM theory [2], XDM also enables evaluating (in an automatic or semi-automatic way) whether the interface is correct and usable.First we will show how a designer can employ the tool in the stepwise building of the interface by extending Coloured Petri Nets with functions associated to places and transitions: this extension provides a logical and physical description of tasks performed, actions that enable performing them, information displayed and their layout. Then we describe how interface behaviour can be simulated in several contexts. We go on to show how designers can verify whether the interface is correct and usable. State of the art and future developments are discussed in the final section.
Computer graphics for the blind
Authors: Ina Satoshi
Published: January 2007

This paper presents a tactile hard-copy system which help an "active tactile graphics" for the blind. Here the word "active" means that the blind can make graphics programs and deal with computer graphics by his own efforts. It translates the color graphics on the screen into an embossed dots image on paper. To get a precise embossed dots hard-copy close to the real graphics screen, we adopted a Braille printer plotter. The program stays resident in computer's memory, and a push of COPY key at any time starts to make an embossed hard-copy of the current graphic screen. By this system and computer language like C, the blind can try to make graphics programs and examine the colors and the graphic figures constructing the screen graphics. The system can extract several combinations of colors from the whole graphics selectively and make the hard-copys. This color selective hard-copys help the blind understand the whole graphics as a result, because each hard-copy reduces the complexity of the graphics and tends to be easier to examine by touch.
Bringing real-time scheduling theory and practice closer for multimedia computing
Authors: Gopalakrishnan R. , Parulkar Gurudatta M.
Published: January 2007

This paper seeks to bridge the gap between theory and practice of real-time scheduling in the domain of high speed multimedia networking. We show that the strict preemptive nature of real-time scheduling leads to more context switching, and requires system calls for concurrency control. We present our scheduling scheme called rate-monotonic with delayed preemption (
rmdp
) and show how it reduces both these overheads. We then develop the analytical framework to analyze
rmdp
and other scheduling schemes that lie in the region between strict (immediate) preemption and no preemption. Our
idealized scheduler simulation
methodology accounts for the blocking introduced by these schemes under the usual assumption that the time for context switching and preemption is zero. We derive simpler schedulability tests for non-preemptive scheduling, and prove a variant of rate-monotonic scheduling that has fewer preemptions. Our measurements on Sparc and Pentium platforms, show that for the workloads we considered,
Rmdp
increases useful utilization by as much as 8%. Thus our scheduling policies have the potential to improve performance over existing methods.
Effective distributed scheduling of parallel workloads
Authors: Dusseau Andrea C. , Arpaci Remzi H. , Culler David E.
Published: January 2007

We present a distributed algorithm for time-sharing parallel workloads that is competitive with coscheduling.
Implicit scheduling
allows each local scheduler in the system to make independent decisions that dynamically coordinate the scheduling of cooperating processes across processors. Of particular importance is the blocking algorithm which decides the action of a process waiting for a communication or synchronization event to complete. Through simulation of bulk-synchronous parallel applications, we find that a simple two-phase fixed-spin blocking algorithm performs well; a two-phase adaptive algorithm that gathers run-time data on barrier wait-times performs slightly better. Our results hold for a range of machine parameters and parallel program characteristics. These findings are in direct contrast to the literature that states explicit coscheduling is necessary for fine-grained programs. We show that the choice of the local scheduler is crucial, with a priority-based scheduler performing two to three times better than a round-robin scheduler. Overall, we find that the performance of implicit scheduling is near that of coscheduling (+/- 35%), without the requirement of explicit, global coordination.
Experiences with network simulation
Authors: Brakmo Lawrence S. , Peterson Larry L.
Published: January 2007

Simulation is a critical tool in developing, testing, and evaluating network protocols and architectures. This paper describes
x
-Sim, a network simulator based on the
x
-kernel, that is able to fully simulate the topologies and traffic patterns of large scale networks. It also illustrates the capabilities and usefulness of the simulator with case studies. Finally, based on our experiences using
x
-Sim, we identify a set of principles (guidelines) for network simulation, and present concrete examples that quantify the value of these principles, along with the cost of ignoring them.
An approximate analysis of waiting time in multi-class
M/G
/1/./
EDF
queues
Authors: Chen Ken , Decreusefond Laurent
Published: January 2007

The Earliest-Deadline-First (EDF) queueing discipline is being more and more widely used for handling time-sensitive applications in computer systems and networks. In this paper, we consider an arbitrary number of traffic classes with class-specific soft-deadline. A soft-deadline is a target waiting-time limit that can be missed. EDF queueing has been proved to minimize the maximum delay overflow related to this limit. We propose a quantitative analysis, through the metric of mean waiting time, on the behavior of EDF queueing. This analysis gives also insight on the correlation between traffic classes with different time-constraints. Technically speaking, we have proven that the mean waiting times for an arbitrary set of
N
classes of traffic streams with soft deadlines are the unique solution of a system of non-linear equations under the constraint of the Kleinrock's conservation law. We then provide an
O
(
N
2
) algorithm to get the solution. Simulation suggests that the theoretical approximation we made is quite acceptable.
Efficient exploration of availability models guided by failure distances
Authors: Carrasco Juan A. , Escribá Javier , Calderón Angel
Published: January 2007

Recently, a method to bound the steady-state availability using the failure distance concept has been proposed. In this paper we refine that method by introducing state space exploration techniques. In the methods proposed here, the state space is incrementally generated based on the contributions to the steady-state availability band of the states in the frontier of the currently generated state space. Several state space exploration algorithms are evaluated in terms of bounds quality and memory and CPU time requirements. The more efficient seems to be a waved algorithm which expands transition groups. We compare our new methods with the method based on the failure distance concept without state exploration and a method proposed by Souza e Silva and Ochoa which uses state space exploration but does not use the failure distance concept. Using typical examples we show that the methods proposed here can be significantly more efficient than any of the previous methods.
How to integrate shared variables in distributed simulation
Authors: Mehl Horst , Hammes Stefan
Published: January 2007

Although users may want to employ shared variables when they program distributed simulation applications, almost none of the currently existing distributed simulation systems does offer this facility. In this paper, we systematically present new algorithms which provide consistent shared variables for distributed simulation applications. Basically, our approach combines known techniques to realize distributed shared memory with simulation algorithms. As there are essentially two classes of distributed simulation algorithms---conservative and optimistic---we study shared variable algorithms for both of them and propose five new algorithms. Initial performance measurements of a prototype implementation are described. Potential performance degradation by the usage of shared variables is expected to depend to a high degree on the access behavior of the simulation application. Having the abstraction of shared variables available provides the user with a simple concept to design distributed simulation applications in the presence of inherent global data.
Abstracts of Japanese computer algebra meeting in Kyoto
Authors: Noda Matu-Tarow
Published: January 2007

These are abstracts of talks given at the 14th RIMS (Research Institute for Mathematical Sciences) Meeting of Computer Algebra and Its Applications in Mathematical Researches. The meeting took place from 20 to 22 in November 1995. In the meeting, 31 talks were presented. Here, short abstracts of almost all talks are shown. If readers have an interest in in some of abstracts, please contact with authors directly or send a message to Matu-Tarow Noda at the address above. Proceedings of the meeting were already published from RIMS as RIMS memoir 941, entitled
Theory of Computer Algebra and Its Applications.
Book review: Mental Leaps: Analogy in Creative Thought By Keith J. Holyoak and Paul Thagard (The MIT Press, 1995)
Authors: Sutherland Karen T.
Published: January 2007

The work behind this excellent and thorough treatise on analogy began during the authors' days in graduate school over 20 years ago. Holyoak, now professor of Psychology at the University of California, Los Angeles, and Thagard, Professor of Philosophy and Adjunct Professor of Psychology and Computer Science at the University of Waterloo, have produced a gem of a book. Commencing with an explanation of their theory of analogy, the book contains a wealth of information, particularly on the development of analogical thought in young humans as well as in lower mammals.
Resolvent and rational canonical forms of matrices
Authors: Della Dora J. , Jung F.
Published: January 2007

The goal of this paper is to explain how to derive from the resolvent of a matrix the following classical rational canonical forms: the Dunford decomposition, the rational spectral decomposition, the Jacobson and the rational Jordan forms (with corresponding change of basis matrices). We do not pretend that this approach is more efficient than other algorithms classically used to build these forms, but we transform theoretical and nonrational methods used in the context of perturbation matrices into effective rational algorithms well adapted to Computer Algebra.
Software infrastructure for non-uniform scientific computations on parallel processors
Authors: Baden Scott B.
Published: January 2007

Non-Uniform representations are an effective means of resolving diverse physical phenomena but they require sophisticated run time support to manage their underlying complexity, especially on parallel computers. I will describe a software infrastructure for non-uniform computations that was developed in my research group, and discuss how this infrastructure was employed in a computational grand challenge: first principle simulation of real materials. At the heart of our infrastructure are the LPARX and KeLP systems, C++ class libraries that offer portable performance across a diversity of hardware platforms.
Maintaining user service and direction in a complex environment
Authors: Ashmore Bill L. , Helm F. Russell , Haerer Sally D.
Published: January 2007

The past decade has witnessed an explosion in both the breadth and depth of computer utilization in all developed countries. Most U.S. installations are hard-pressed simply to keep themselves aware of new hardware and software, much less to play any active role in the always exciting area of applications development. Universities feel this burden with special sensitivity due to their traditional dual roles of education and research. Not as visible, but nonetheless critical, are the needs associated with the effective administration of a modern university complex. Pushed on by a strong sense of professional responsibility and pulled into the whirlwind by an increasingly demanding user base, educational centers have typically responded by simply placing themselves into motion, hoping to satisfy requirements due to action itself. Many such actions have been next to useless and have led to frustration among all involved parties. It is mandatory that a sense of direction be maintained during any period of rapid change; the alternative is Brownian motion.
Report on a program for solving polynomial equations in non-commuting variables
Authors: Labonté Gilles
Published: January 2007

We now have a program to solve automatically the following problem. Let one be given a set of equations:[EQUATION]in which the p's are polynomials, with coefficients in a skew-field K, and in which the unknowns m
1
, m
2
,..., m
n
are generally non-intercommuting but can also intercommute. Find the possible representations for the ring of polynomials generated by the m's; Eqs (1) being assumed to define a finite ring.
Some simple pretty-print facilities for REDUCE
Authors: van den Heuvel P , Hulshof B J A , van Hulzen J A
Published: January 2007

Some simple REDUCE facilities are presented for pretty-printing quotients, formal derivatives and subscripted variables. The package, an extension of previously published possibilities, is completely written in RLisp and can be considered as an addition to the output repertoire of the Algebraic Mode.
John Reid reports: X3J3 meeting, August 1986
Authors: Reid John
Published: January 2007

The meeting was dominated by the themes of correctlng errors in the draft document (S8) and improving its readability, making the technical changes that were agreed at the previous meeting as part of the compromise that reduces the size of the language, and reacting to the ISO meeting held in the previous week. It now looks likely that a fresh letter ballot will be held on the version of S8 that includes all the changes made at this and the next meeting in November and that the February meeting will be devoted to processing the ballots. A straw roll-call ballot on how those members present at Halifax expected to vote in this ballot was 24-6, so it looks as if the compromise will obtain the two-thirds majority needed.
A new theoretical framework for information retrieval
Authors: Van Rijsbergen C J
Published: January 2007

A new framework based on a non-classical logic is proposed for investigating IR. The paper motivates the use of a particular conditional logic as the 'right' logic for IR. A new principle, the
logical uncertainty principle
, is proposed, to deal with the inherent uncertainty associated with applicable inferences.
A computerized test for conformance to the APL standard
Authors: Amer Kaled A
Published: January 2007

This chapter is not intended to fully acquaint the reader with APL. For this purpose the reader is referred to Grey [5]. Here we give a brief history of the language and its uses. Some features which set APL apart from more traditional languages such as Pascal and Fortran are discussed. Also discussed are APL random files, which are essential to the work of subsequent chapters.
Book review: MENTAL SPACES: ASPECTS OF MEANING CONSTRUCTION IN NATURAL LANGUAGE by Gilles Fauconnier (Bradford/MIT Press)
Authors: Dinsmore John
Published: January 2007

Expert systems are now recognized as key elements in the computing systems of the future, and the most significant applications of AI. Expert systems are already being used in such varied fields as medicine, engineering, chemistry and business.
Selected AI-related dissertations
Authors: Krovetz Bob
Published: January 2007

The following are citations selected by title and abstract as being related to Al, resulting from a computer search, using the BRS Information Technologies retrieval service, of the Dissertation Abstracts International (DAI) database produced by University Microfilms International.
AI: Just how scattered is the literature?
Authors: Mills W. J.
Published: January 2007

It is a commonplace that the literature of Al is scattered. This paper presents evidence as to the extent of that scatter and explores some of the implications for how best to locate relevant literature.
Compiling LISP procedures
Authors: Pumplin B A
Published: January 2007

The programming language LISP is frequently the language of choice for the implementation of artificial intelligence (AI) systems, even though it has earned a reputation for being slow. This lack of speed is usually due to the fact that commonly available LISP implementations are interpretive in nature rather than compile and go. And we all know that interpreting source code is invariably slower than simply executing the compiled object code.
GRG
EC
Authors: Tertychniy S. I. , Obukhova I. G.
Published: January 2007

We present a general outline of the specialized computer algebra system GRC
EC
intended for symbolic calculations in the field of the gravitation theory, the classical field theory on a curved background, and the adjacent methods belonging to the differential geometry. The distinctive features of the GRC
EC
input language are exhibited and the noteworthy elements of the system design are discussed.
THE INTUITIVE SIDE OF PROGRAMMING
Authors: Molzberger Peter
Published: January 2007

Looking at Software Development we find two complementary aspects. On one side it is an activity of the rational mind, highly supportable by formalization and tools. On the other side we have creativity and intuition. A synergy of these two aspects may lead to what we call "excellence."
Book review: Designing the User Interface: Strategies for Effective Human-Computer Interaction by Ben Shneiderman (Addison-Wesley, 1987)
Authors: Nielsen Jakob
Published: January 2007

This is Ben Shneiderman's new textbook to replace his classic
Software Psychology
from 1980 and as such it has been eagerly awaited - at least by me. Compared with the 1980 book, the 1987 book (actually published in the summer of 1986) is a big step forward: It has a considerably clearer organization and much better coverage of important issues such as interaction styles and manuals. This improvement is in itself a proof that our field has made real progress in this decade. The new book has more of a focus on user interfaces for end users, while the 1980 book (as implied by its name) included much more material on the human factors of the programming process itself.
ANDYMMO
Authors: Hahn Willi , Hasenjäger Erwin , Trautmann Jens
Published: January 2007

The dynamics of mechanical and/or control systems is traditionally documented by plots of system variables. The imagination of the underlying movements is restricted to very simple cases.ANDYMMO enhances imagination by introducing the possibility to see animated sequences of movements. The source may be any output generated by standard simulation tools. For linear models ANDYMMO has its own buiIt-in simulator.
Dataflow analysis in APL
Authors: Budd Timothy A.
Published: January 2007

An algorithm is described to perform dataflow analysis on programs written in an APL-like language. The dataflow analysis is performed at both the intra and interprocedural levels. The algorithm presented here is simpler and tailored more directly to the target language than previously published algorithms for dataflow analysis in APL. These algorithms have been implemented as part of a APL compiler.
APL teaching bugs
Authors: Peelle Howard A. , Eisenberg Murray
Published: January 2007

This paper discusses “APL teaching bugs”, in three senses: (1) issues inherent in the teaching of APL that confront the instructor with difficult choices; (2) potential mistakes sometimes made by instructors teaching APL; and (3) problematic aspects of the design of APL that are especially difficult to explain. These teaching bugs are presented as provocative questions, but the “answers” are left to individual instructors. By facing these questions, teachers may make APL more comprehensible and hence foster its acceptance and growth.
Structural experiments with arrays of functions
Authors: Benkard J. Philip
Published: January 2007

Proposals have been made to include function arrays in APL syntax. Strand syntax extends to provide vectors; bracket semantics, to provide reshaping.

Herein the structure phase of expression evaluation, which is APL's unique addition to the more familiar syntax and semantics phases, is analyzed. To the two argument shapes of VSAPL must be added the function shape. The extension of the conformance rules is straightforward; scalar conformance is the driving mechanism; applied recursively it is the basis of pervasion. Function and data arrays used with EACH and ENCLOSE, respectively, to produce scalars, lead to identities involving TRANSPOSE, DISCLOSE, and OUTER PRODUCT.

Analysis of the nonpervasive scalar function RHO EACH suggests what structural information must be retained in an empty function array. A vector of derived functions is a useful alternative to a derived function with an EACH in some common circumstances. A historical survey suggests that adding function vectors to APL2 would enhance the symmetry and balance of the language.
APLGRAPH—how to develop graphics software without really trying
Authors: Ylinen Tauno
Published: January 2007

The paper describes the development process and system structure of a presentation graphics software written in APL, and shows its user characteristics through a few examples.
A new method for analysing feedback-based protocols with applications to engineering Web traffic over the Internet
Authors: Heyman D. P. , Lakshman T. V. , Neidhardt Arnold L.
Published: January 2007

Most of the studies of feedback-based flow and congestion control consider only persistent sources which always have data to send. However, with the rapid growth of Internet applications built on TCP/IP such as the World Wide Web and the standardization of traffic management schemes such as Available Bit Rate (ABR) in Asynchronous Transfer Mode (ATM) networks, it is essential to evaluate the performance of feedback-based protocols using traffic models which are specific to dominant applications. This paper presents a method for analysing feedback-based protocols with a Web-user-like input traffic where the source alternates between "transfer" periods followed by "think" periods. Our key results, which are presented for the TCP protocol, are:(1) The goodputs and the fraction of time that the system has some given number of transferring sources are
insensitive
to the distributions of transfer (file or page) sizes and think times except through the ratio of their means. Thus, apart from network round-trip times, only the ratio of average transfer sizes and think times of users need be known to size the network for achieving a specific quality of service.(2) The Engset model can be adapted to accurately compute goodputs for TCP and TCP over ATM, with different buffer management schemes. Though only these adaptations are given in the paper, the method based on the Engset model can be applied to analyze other feedback systems, such as ATM ABR, by finding a protocol specific adaptation. Hence, the method we develop is useful not only for analysing TCP using a source model significantly different from the commonly used persistent sources, but also can be useful for analysing other feedback schemes.(3) Comparisons of simulated TCP traffic to measured Ethernet traffic shows qualitatively similar autocorrelation when think times follow a Pareto distribution with infinite variance. Also, the simulated and measured traffic have long range dependence. In this sense our traffic model, which purports to be Web-user-like, also agrees with measured traffic.
Preprototyping SIMD coprocessors using virtual machine emulation and trace compilation
Authors: Herbordt Martin C. , Kidwai Owais , Weems Charles C.
Published: January 2007

The use of massively parallel SIMD array architectures is proliferating in the area of domain specific coprocessors. Even so, they have undergone few systematic empirical studies. The underlying problems include the size of the architecture space, the lack of portability of the test programs, and the inherent complexity of simulating up to hundreds of thousands of processing elements. We address the computational cost problem with a novel approach to trace-based simulation. Code is run on an abstract virtual machine to generate a coarse-grained trace, which is then refined through a series of transformations (a process we call
trace compilation
) wherein greater resolution is obtained with respect to the details of the target machine. We have found this technique to be one to two orders of magnitude faster than instruction-level simulation while still retaining much of the accuracy of the model. Furthermore, abstract machine traces must be regenerated for only a small fraction of the possible parameter combinations. Using virtual machine emulation and trace compilation also addresses program portability by allowing the user to code in a single data parallel language with a single compiler, regardless of the target architecture. This technique has already been used to generate significant results with respect to SIMD array architectures, a sample of which are presented here.
Second moment resource allocation in multi-service networks
Authors: Knightly Edward W.
Published: January 2007

A crucial problem for the efficient design and management of integrated services networks is how to best allocate network resources for heterogeneous and bursty traffic streams in multiplexers that support prioritized service disciplines. In this paper, we introduce a new approach for determining per-connection performance parameters such as delay-bound violation probability and loss probability in multi-service networks. The approach utilizes a traffic characterization consisting of the variances of a stream's rate distribution over multiple interval lengths, which captures its burstiness properties and autocorrelation structure. From this traffic characterization, we provide a simple and efficient resource allocation algorithm by deriving stochastic delay-bounds for static priority schedulers and employing a Gaussian approximation over intervals. To evaluate the scheme, we perform trace-driven simulation experiments with long traces of MPEG-compressed video and show that our approach is accurate enough to capture most of the inherent statistical multiplexing gain, achieving average network utilizations of up to 90% for these traces and substantially outperforming previous "effective bandwidth" techniques.
Design and evaluation of a DRAM-based shared memory ATM switch
Authors: Chiueh Tzi-cker , Varadarajan Srinidhi
Published: January 2007

Beluga
is a single-chip switch architecture specifically targeted at local area ATM networks, and it features three architectural innovations. First, an interconnection hierarchy composed of multiple switching fabrics is built into the chip to provide both low-latency cell transfer when the traffic is light and low cell drop rate under heavy load. Secondly, to improve silicon efficiency, Beluga is based on shared memory architecture, and the buffers are implemented using DRAM rather than SRAM technology. Heavy interleaving and selective invalidation are used to address long latency and periodic refreshing problems, respectively. Thirdly, Beluga supports multicast with minimal physical bit replication. It also separates support for unicast and multicast cells to optimize for the common case, where multicast cells occur infrequently. This paper describes the design details of
Beluga
and the results of a comprehensive simulation study to quantify the performance impact of each of its architectural features. The most important result from this research is that DRAM-based buffer implementation significantly reduces the cell-drop rate during heavy while exhibiting almost identical cell latency to SRAM-based implementation during light load. Therefore, we believe DRAM makes an attractive alternative for switch buffer implementation, especially for single-chip architecture such as
Beluga.
Efficient retrieval of composite multimedia objects in the
JINSIL
distributed system
Authors: Song Junehwa , Dan Asit , Sitaram Dinkar
Published: January 2007

In a distributed environment, presentation of structured, composite multimedia information poses new challenges in dealing with variable bandwidth (BW) requirement and synchronization of media data objects. The detailed knowledge of BW requirement obtained by analyzing the document structure can be used to create a prefetch schedule that results in efficient utilization of system resources. A distributed environment consists of various system components that are either dedicated to a client or shared across multiple clients. Shared system components could benefit from
Fine Granularity Advanced Reservation (FGAR)
of resources based on true BW requirement. Prefetching by utilizing advance knowledge of BW requirement can further improve resource utilization. In this paper, we describe the JINSIL retrieval system that takes into account the available bandwidth and buffer resources and the nature of sharing in each component on the delivery path. It reshapes BW requirement, creates prefetch schedule for efficient resource utilization in each component, and reserves necessary BW and buffer. We also consider good choices for placement of prefetch buffers across various system components.
Buffer sharing in video-on-demand servers
Authors: Shi Weifeng , Ghandeharizadeh Shahram
Published: January 2007

This paper describes a buffer sharing technique that strikes a balance between the use of disk bandwidth and memory in order to maximize the performance of a video-on-demand server. We make the key observation that the configuration parameters of the system should be independent of the physical characteristics of the data (e.g., popularity of a clip). Instead, the configuration parameters are fixed and our strategy adjusts itself dynamically at run-time to support a pattern of access to the video clips.
Complexity, ontology, and the causal Markov assumption
Authors: Losiewicz Paul B.
Published: January 2007

The question of what constitutes a causal model is significant, as it will lead to a better understanding of the role of causality and its heuristic role in probabilistic reasoning. It has been argued that in certain cases domain specific considerations can be appealed to in the construction of more efficient causal models that are "nonstandard" in the way networks reflect anomalous correlations between nodes. For the most part, the causal assumptions generally invoked [Pearl 1988], [Spirtes, Glymour, Scheines 1993] do lead to systematic efficiencies based on a reduction in computational requirements for the models they produce. The goal of this paper is to uncover some of the assumptions about causality that undergird current causal models, assumptions which should be kept in mind by those invoking causal relations in the construction of discovery algorithms for causal networks.