bluuebunny/crossref_metadata_2025 huggingface dataset:
APL in operating systems research
Authors: Johnson Greg
Published: January 2007

This paper will discuss three extensions to APL which will improve its usefulness for research in operating systems and systems programming. They are the introduction of processor variables, encased and bound statement fragments, and pointer or referent variables. APL has demonstrated capabilities in free-wheeling research environments. In an experimental operating system written in APL, much superfluous detail would be suppressed, and the essentials of various algorithms used would be brought to the fore.
A portable APL language test generation and verification system
Authors: Nylander Charles G.
Published: January 2007

The major tasks that must be performed during development and use of an APL language test system include construction of tests and verification of test results. In addition, it is desirable that a test system be transportable to a variety of APL language implementations, be extensible, and allow easy revalidation of the language implementation.

In this paper, we will describe the design, implementation, and use of an extensible, portable, self-verifying APL test system that includes facilities to generate large sets of useful tests with very little effort.

The test system is based on a test definition language and on an executable formal definition of the APL language. By careful use of the test system, 150,000 self-verifying language tests were constructed in four man-weeks.

Transportability was achieved by using APL as the implementation language for the test system software.

The successful use and transportation of this test system demonstrates that it is relatively easy to generate tests for and in the APL language.
The class concept in the Simula programming language
Authors: Palme Jacob , Wallin Mats
Published: January 2007

This paper is directed at APL-users who wants a quick introduction into the main features of the Simula programming language. Simula is a general purpose high-level language. Good Simula systems exist on most large computers. The paper describes the methods for program and data structuring in Simula. These are well suited for structured programming and for the production of secure, modular programs. The paper also points at some major differences between Simula and APL.
Is APL a programming language or isn't it?
Authors: Perlis Alan J.
Published: January 2007

It is a matter of both pride and concern to APL programmers that APL appears to develop in ways different from all other programming languages. This talk will attempt to answer why this is so. Comparisons will be made between the directions of APL development and those of the ALGOL family and LISP.
Nested arrays, operators, and functions
Authors: Smith Bob
Published: January 2007

Although the original ideas of nested arrays go back over ten years, it has been only within the past few years that these ideas have matured. During the same period, several new operators and functions have been proposed. This paper describes an experimental research implementation of these proposals. Details of some of the proposals are also described.
TAGINE, an interactive tool for report generation
Authors: Yazigi Colette
Published: January 2007

This paper describes an APL tool designed as an aid to report writing.

Using APL formatting symbols is quite difficult, and the report formatting phase of a business application program is often very long: TAGINE has been designed to allow quick and easy programming of reports.

TAGINE is divided into two modules:

1 - TANA is a simple macro-language intended for describing computations to be performed, and building a model of the final report (with automatic justifications, titles, formatting and decoration).

2 - TEDI performs the report generating using the model that has been stored. Most frequently, the end-user uses only the TEDI module.

At the APL division of SLIGOS, we have been using TAGINE for one year and have reduced the report programming effort by a factor of 10 compared to direct use of formatting primitives.

We have built 400 models with TANA, and produced 10000 tables with TEDI.

Systematic use of TAGINE has greatly improved:

• Applications portability

• Linking of a variety of applications

• Product maintenance and reliability
Designing efficient algorithms for APL
Authors: Gofman Emanuel , Rodeh Michael
Published: January 2007

The interpretation time of
APL
instructions significantly influences the total execution time and therefore must be considered during the development of
APL
programs. As an example of the trade off between interpretation and execution time, the redesign process of a hydraulic network solver originally intended for implementation in
FORTRAN
is described. Efficiency is gained both by designing algorithms which have a more parallel nature and by extensive use of precomputations. It is shown that evaluating an algorithm using the classical method of counting the number of “basic steps” is insufficient in an APL context.
Determining probability distributions by maximum entropy and minimum cross-entropy
Authors: Johnson Rodney W.
Published: January 2007

The principle of maximum entropy and a generalization, the principle of minimum cross entropy, are prescriptions for solving problems of the following sort, which are encountered in a remarkable number of different fields. Namely, some system may be in any one of a given set of states; the probabilities of its being in the various states are not specified, but information about the probability distribution is available in the form of expectation values of given functions on the set of states. It is required to assign an optimal, or minimally prejudiced, set of state probabilities consistent with the given information. This paper describes the principles and presents APL functions that use the Newton-Raphson method to compute maximum-entropy and minimum-cross-entropy probability distributions for arbitrary sets of given expectation values. Example calculations are given.
Relational data-base management and APL
Authors: Codd E. F.
Published: January 2007

Historically, the development of programming languages was driven by a desire to remove needless machine-oriented representation clutter from the programmer's purview. When compared with other implemented programming languages, APL goes quite far in this direction. However, like its competitors, APL provides almost no support for programs that have to access and possibly update data from shared data bases. Such data is usually subject to syntactic and semantic constraints that are declared on a community basis. Moreover, both the data and the constraints are subject to dynamic sharing with other independently-developed programs.

We outline the principles underlying the relational model for formatted data bases, including the structures, algebraic operators, normalization, and formal data sublanguages. We conclude with a discussion of the need for a knowledge base (1) to act as a defining base for a proposed data base; (2) to mediate queries and transactions; and (3) to aid in query formulation in formal or natural language.

A short list of references is given for those wishing more introductory information about relational database management.
The nested rectangular array as a model of data
Authors: More Trenchard
Published: January 2007

Data, like electricity and gravity, are part of the world in which we live. Some occur naturally, as in the genetic code, while most occur as a consequence of language and social organization. The search for a theory of data, which begins with the choice of a model, is as important and interesting as the development of theories in physics, economics, and psychology.

Most models of data are collections, such as the unnested array of APL, the one-axis nested list of LISP, and the set, which is nested but lacks the properties of order, repetitions, type, and multiple axes inherent in rectangular arrangement. Nested rectangular arrays have all these properties. The existence of simple, universally valid equations in both set theory and linear algebra suggests that equally simple equations may hold for all arrays. The principles of nested collections developed in set theory apply with few changes to the nesting of arrays. A one-sorted theory of arrays, in which type is preserved for empty arrays, provides an algebra of operations interpreted not only for data but also types of data.
A note on pattern matching
Authors: Falkoff Adin D.
Published: January 2007

The question in the title is answered, and the answer justified by a derivation and use in two applications, string partitioning and string editing. Some implications for APL language extensions are also noted.
A latent-expression exception-handling system
Authors: Gilmore John C. , Puckett Thomas H.
Published: January 2007

This paper describes an Exception-Handling Facility implemented in the
APL*PLUS*
System which uses latent expressions similar to @@@@
LX
as the primary mechanism. Separate expressions are used to deal with errors which occur within the execution of
APL
statements, and with use of the break key on a terminal during statement execution. This allows application packages to deal directly and automatically with many situations which previously required intervention on the part of the user of the package. The facility also includes a means of providing information on the nature of the exception, and providing protection against security breaches for certain cases in which the exception handlers cannot perform their normal functions.
Using an APL macroprocessor to implement generalized software systems
Authors: Dempsey Mark R.
Published: January 2007

Several techniques for implementing generalized software packages in
APL
are considered. One technique in particular, data-driven code generation, is expanded upon. When this technique is employed, application software is written in template form. These templates are then compiled into
APL
objects when an individual application is configured. Some areas which are investigated are the use of software templates, an
APL
macrolanguage, and an
APL
macroprocessor. Specific examples relevant to data base management systems are presented.
Teaching computer science with APL
Authors: Denenberg Stewart A. , Peelle Howard A.
Published: January 2007

We suggest that APL be used to teach selected topics in computer science. As a case in point, we take the topic:

“An Introduction to Search Procedures for Problem-Solving”

This is the first topic in a series of experimental curriculum units currently being developed at the University of Massachusetts.

In this paper, recursive APL functions are used to demonstrate fundamental search procedures, namely:

Breadth-First Search

Depth-First Search

Random Search

Heuristic Search

For illustration, a simplified Water Jug Problem is used with a state-space representation. The reader is invited to consider programming enhancements as well as extensions to other problems.

In closing, we cite some other topics potentially suitable for teaching with APL and mention implications for computer-science education.
Management of APL public libraries
Authors: Boisvert Marguerite A.
Published: January 2007

Ten years of APL public-library acquisitions were sorted through, reduced in quantity, and reorganized. Policies intended to assure high quality in new acquisitions were developed, and programs were created both to support these policies and to provide ease of access to all public-library materials.
Symbolic integration of expressions involving unspecified functions
Authors: Campbell Graham H.
Published: January 2007

The problem of determining an expression whose derivative is a specified expression when that expression involves unspecified functions is analyzed. An algorithm is presented which reduces this problems to that of integration of specified functions.
Validation of a Jungian instrument for MIS research
Authors: Mawhinney Charles H. , Lederer Albert L.
Published: January 2007

The Jungian personality typology has been widely used in MIS research to investigate personal characteristics of MIS participants. The Personal Style Inventory (PSI) is a Jungian instrument in the public domain which has received little previous attention from the MIS community. Reliability, concurrent validity, and construct validity were investigated in an experiment where this instrument was directly compared with the Abbreviated Version of the Myers-Briggs Type Indicator (MBTI/AV) utilizing a sample of undergraduate business majors. Although the PSI was found to be a somewhat weaker instrument, the ability to directly incorporate it into other questionnaires makes it a useful tool for research utilizing a blind mail survey methodology.
Winter 1988 Daedalus
Authors: Agassi Joseph
Published: January 2007

The last issue of Daedalus, Journal of the American Academy of Arts and Sciences, Winter 1988, is devoted to artificial intelligence--Al, for short. It is always interesting to know what is the official position of the intellectual establishment on intellectual matters, especially where much grant allocation is concentrated.
Animation Using Temporal Constraints
Authors: Duisberg Robert A.
Published: January 2007

Algorithm animation has a growing role in computer aided algorithm design, documentation and debugging, since interactive graphics is a richer channel than text for communication. Most animation is currently done laboriously by hand, and it often has the character of canned demonstrations with restricted user interaction. Animus is a system that allows easy construction of an animation with minimal concern for lower level graphics programming. Constraints are used to describe the appearance and structure of a picture as well as how those pictures evolve in time. The implementation and support of temporal constraints is a substantive extension to previous constraint languages which had only allowed specification of static state. Use of the Animus system is demonstrated in the creation of animations of dynamic mechanical and electrical circuit simulations, sorting algorithms, problems in operating systems, and geometric curve drawing algorithms.
Parallel processors and systems for algebraic manipulation: current work
Authors: Ponder Carl G.
Published: January 2007

What efforts are needed to produce a parallel system (computer architecture and interconnection network) for fast algebraic manipulation? This paper outlines current steps toward such a system, including work in related areas of parallel symbolic processing languages and general- and special-purpose multiprocessor systems.
Evaluation of guidelines for designing accessible Web content
Authors: Colwell Chetz , Petrie Helen
Published: January 2007

This study evaluates the Web Content Accessibility (WCA) guidelines, developed by the Web Accessibility Initiative (WAI). The first aim of this study was to investigate whether the Guidelines can be used effectively by Web page authors. To this end students of HTML (Hyper Text Mark-up Language) used the Guidelines to adapt Web pages. The second aim of the study was to examine whether pages developed using the Guidelines are accessible to visually impaired people. In order to achieve this visually impaired Web users assessed the accessibility of the pages developed by the Web page authors. The study found some difficulties in the use of the Guidelines that were similar to those identified by previous research. There were unexpected results regarding the accessbility of certain HTML elements.
Factoring a binary polynomial of degree over one million
Authors: Bonorden Olaf , von zur Gathen Joachim , Gerhard Jürgen , Müller Olaf
Published: January 2007

On 22 May 2000, the factorization of a pseudorandom polynomial of degree 1 048 543 over the binary field Z
2
was completed on a 4-processor Linux PC, using roughly 100 CPU-hours. The basic approach is a combination of the factorization software BIPOLAR and a parallel version of Cantor's multiplication algorithm. The PUB-library (Paderborn University BSP library) is used for the implementation of the parallel communication.
Mining data streams under block evolution
Authors: Ganti Venkatesh , Gehrke Johannes , Ramakrishnan Raghu
Published: January 2007

In this paper we survey recent work on incremental data mining model maintenance and change detection under
block evolution.
In block evolution, a dataset is updated periodically through insertions and deletions of
blocks
of records at a time. We describe two techniques: (1) We describe a generic algorithm for model maintenance that takes any traditional incremental data mining model maintenance algorithm and transforms it into an algorithm that allows restrictions on a temporal subset of the database. (2) We also describe a generic framework for change detection, that quantifies the difference between two datasets in terms of the data mining models they induce.
KDD Cup 2001 report
Authors: Cheng Jie , Hatzis Christos , Hayashi Hisashi , Krogel Mark-A. , Morishita Shinichi , Page David , Sese Jun
Published: January 2007

This paper presents results and lessons from KDD Cup 2001. KDD Cup 2001 focused on mining biological databases. It involved three cutting-edge tasks related to drug design and genomics.
MDM/KDD
Authors: Zaïane Osmar R. , Simoff Simeon J.
Published: January 2007

This is brief report summarizes the presentations, conclusions and directions for future work that were discussed during the second edition of the International Workshop on Multimedia Data Mining. The report includes references to resources where one can find more information about the workshop format, the proceedings and the workshop participants.
A preprocessing scheme for high-cardinality categorical attributes in classification and prediction problems
Authors: Micci-Barreca Daniele
Published: January 2007

Categorical data fields characterized by a large number of distinct values represent a serious challenge for many classification and regression algorithms that require numerical inputs. On the other hand, these types of data fields are quite common in real-world data mining applications and often contain potentially relevant information that is difficult to represent for modeling purposes.This paper presents a simple preprocessing scheme for high-cardinality categorical data that allows this class of attributes to be used in predictive models such as neural networks, linear and logistic regression. The proposed method is based on a well-established statistical method (empirical Bayes) that is straightforward to implement as an in-database procedure. Furthermore, for categorical attributes with an inherent hierarchical structure, like ZIP codes, the preprocessing scheme can directly leverage the hierarchy by blending statistics at the various levels of aggregation.While the statistical methods discussed in this paper were first introduced in the mid 1950's, the use of these methods as a preprocessing step for complex models, like neural networks, has not been previously discussed in any literature.
G
ISMO
Authors: Jin Shudong , Bestavros Azer
Published: January 2007

This paper presents a tool called G
ISMO
(Generator of Internet Streaming Media Objects and workloads). G
ISMO
enables the specification of a number of streaming media access characteristics, including object popularity, temporal correlation of request, seasonal access patterns, user session durations, user inter-activity times, and variable bit-rate (VBR) self-similarity and marginal distributions. The embodiment of these characteristics in G
ISMO
enables the generation of realistic and scalable request streams for use in the benchmarking and comparative evaluation of Internet streaming media delivery techniques. To demonstrate the usefulness of G
ISMO
, we present a case study that shows the importance of various workload characteristics in determining the effectiveness of proxy caching and server patching techniques in reducing bandwidth requirements.
Network tomography on general topologies
Authors: Bu Tian , Duffield Nick , Presti Francesco Lo , Towsley Don
Published: January 2007

In this paper we consider the problem of inferring link-level loss rates from end-to-end multicast measurements taken from a collection of trees. We give conditions under which loss rates are identifiable on a specified set of links. Two algorithms are presented to perform the link-level inferences for those links on which losses can be identified. One, the
minimum variance weighted average (MVWA) algorithm
treats the trees separately and then averages the results. The second, based on
expectation-maximization (EM)
merges all of the measurements into one computation. Simulations show that EM is slightly more accurate than MVWA, most likely due to its more efficient use of the measurements. We also describe extensions to the inference of link-level delay, inference from end-to-end unicast measurements, and inference when some measurements are missing.
Characterizing the
d
-TLB behavior of SPEC CPU2000 benchmarks
Authors: Kandiraju Gokul B. , Sivasubramaniam Anand
Published: January 2007

Despite the numerous optimization and evaluation studies that have been conducted with TLBs over the years, there is still a deficiency in an indepth understanding of TLB characteristics from an application angle. This paper presents a detailed characterization study of the TLB behavior of the SPEC CPU2000 benchmark suite. The contributions of this work are in identifying important application characteristics for TLB studies, quantifying the SPEC2000 application behavior for these characteristics, as well as making pronouncements and suggestions for future research based on these results.Around one-fourth of the SPEC2000 applications (ammp, apsi, galgel, lucas, mcf, twolf and vpr) have significant TLB missrates. Both capacity and associativity are influencing factors on miss-rates, though they do not necessarily go hand-in-hand. Multi-level TLBs are definitely useful for these applications in cutting down access times without significant miss rate degradation. Superpaging to combine TLB entries may not be rewarding for many of these applications. Software management of TLBs in terms of determining what entries to prefetch, what entries to replace, and what entries to pin has a lot of potential to cut down miss rates considerably. Specifically, the potential benefits of prefetching TLB entries is examined, and Distance Prefetching is shown to give good prediction accuracy for these applications.
Evaluating tradeoffs of congestion pricing for voice calls
Authors: Shih Jimmy S. , Katz Randy H.
Published: January 2007

We conducted user experiments and simulations to understand the tradeoffs of congestion pricing between system performance and user satisfaction for a large community of users. We found that congestion pricing can be effective for voice calls because it only needs to be applied occasionally and that users are responsive to occasional price increases.
Some new disk scheduling policies and their performance
Authors: Thomasian Alexander , Liu Chang
Published: January 2007

Advances in magnetic recording technology have resulted in a rapid increase in disk capacities, but improvements in the mechanical characteristics of disks have been quite modest. For example, the access time to random disk blocks has decreased by a mere factor of two, while disk capacities have increased by several orders of magnitude. OLTP applications subject disks to a very demanding workload consisting of accesses to randomly distributed disk blocks and gain limited benefit from caching and prefetching (at the onboard disk cache). We propose some new disk scheduling methods to address the limited disk access bandwidth problem.Some well-known disk scheduling methods are: (i) FCFS. (ii) Shortest Seek Time First (SSTF). (iii) SCAN and Cyclical SCAN (CSCAN). The latter moves the disk arm to its beginning point after each SCAN so that requests at all disk cylinders are treated symmetrically. (iv) CSCAN with a lookahead of next
i
requests (CSCAN-LAi) takes into account latency to reorder their processing to minimize the sum of their service times. (v) Shortest Access Time First (SATF), which provides the best performance [2]. (vi) SATF with lookahead for
i
requests (SATF-LAi).In the case of SATF-LAi with
i
= 2 after the completion of request
X
the scheduler chooses requests
A
and
B
such that the sum of their service times processed consecutively, i.e.,

t
X,A

+

at
A,B
,

is minimized. In
SATF with flexible lookahead
only request
A
is definitely processed and request
B
is processed provided that it is selected in the next round. We refer to
a
as the
discount factor
(0 ≤
a
≤ 1), because less weight is attached to the service time of request
B,
since it may not be processed after request
A.
The case
a
= 0 corresponds to pure SATF. When
a
= 1 we consider a variant called
SATF with fixed lookahead
where
B
is processed unconditionally after
A
before any other other (perhaps more favorable recent) requests. Thus requests are processed two at a time, unless only one request is available. More generally requests in the temporal neighborhood of request
A
are given higher priority.
On the sensitivity of cooperative caching performance to workload and network characteristics
Authors: Lee Kang-Won , Amiri Khalil , Sahu Sambit , Venkatramani Chitra
Published: January 2007

A rich body of literature exists on several aspects of cooperative caching [1, 2, 3, 4, 5], including object placement and replacement algorithms [1], mechanisms for reducing the overhead of cooperation [2, 3], and the performance impact of cooperation [3, 4, 5]. However, while several studies have focused on quantifying the performance benefit of cooperative caching, their conclusions on the effectiveness of such cooperation vary significantly. The source of this apparent disagreement lies mainly in their different assumptions about workload and network characteristics, and about the degree of cooperation among caches.To more comprehensively evaluate the practical benefit of cooperative caching, we explore the sensitivity of the benefit of cooperation to workload characteristics such as
object popularity distribution, temporal locality, one time referencing behavior,
and to network characteristics such as
latencies between clients, proxies, and servers.
Furthermore, we identify a critical workload characteristic, which we call
average access density,
and show that it has a crucial impact on the effectiveness of cooperative caching.In this extended abstract, we report on a few important results selected from our extensive study reported in [6]. In particular, assuming an LFU-based cache management policy, we arrive at the following conclusions. First, cooperative caching is only effective when the
average access density
(defined as the ratio of the number of requests to the number of distinct objects in a time window) is relatively high. Second, the effectiveness of cooperative caching decreases as the skew in object popularity increases. Higher skew means that only a small number of objects are most frequently accessed reducing the benefit of larger caches, and therefore of cooperation.
A method for estimating non-responsive traffic at a router
Authors: Zhao Zhili , Ametha Jayesh , Darbha Swaroop , Reddy A. L. Narasimha
Published: January 2007

In this paper, we propose a scheme for estimating the proportion of the incoming traffic that is not responding to congestion at a router. The idea of the proposed scheme is that if the observed queue length and packet drop probability do not match with the predicted results from the TCP model, then the error must come from the non-responsive traffic; it can then be used for estimating non-responsive traffic. The proposed scheme utilizes queue length history, packet drop history, expected TCP and queue dynamics to estimate the proportion. We show that the proposed scheme is effective over a wide range of traffic scenarios through simulations.
Forwarders vs. centralized server
Authors: Alouf Sara , Huet Fabrice , Nain Philippe
Published: January 2007

The Internet has allowed the creation of huge amounts of data located on many sites. Performing complex operations on some data requires that the data be transferred first to the machine on which the operations are to be executed, which may require a non-negligible amount of bandwidth and may seriously limit performance if it is the bottleneck. However, instead of moving the data to the code, it is possible to move the code to the data, and perform all the operations locally. This simple idea has led to a new paradigm called
code-mobility:
a mobile object --- sometimes called an agent --- is given a list of destinations and a series of operations to perform on each one of them. The agent will visit all of the destinations, perform the requested operations and possibly pass the result on to another object. Any mobility mechanism must first provide a way to migrate code from one host to another. It must also ensure that any communication following a migration will not be impaired by it, namely that two objects should still be able to communicate even if one of them has migrated. Such a mechanism is referred to as a
location
mechanism since it often relies on the knowledge of the location of the objects to ensure communications. Two location mechanisms are widely used: the first one uses a centralized server whereas the second one relies on special objects called
forwarders.
This paper evaluates and compares the performance of an existing implementation of these approaches in terms of cost of communication in presence of migration. Based on a Markov chain analysis, we will construct and solve two mathematical models, one for each mechanism and will use them to evaluate the cost of location. For the purpose of validation, we have developed for each mechanism a benchmark that uses
ProActive
[2], a Java library that provides all the necessary primitives for code mobility. Experiments conducted on a LAN and on a MAN have validated both models and have shown that the location server always performs better than the forwarders. Using our analytical models we will nevertheless identify situations where the opposite conclusion holds. However, under most operational conditions location servers will perform better than forwarders.
Enumeration in the Chevalley algebras
Authors: Egorychev Georgy P. , Levchuk Vladimir M.
Published: January 2007

We consider the maximal nilpotent subalgebra NΦ(
K
) of the Chevalley algebra of the type Φ over an arbitrary field
K
. Our purpose is enumeration of ideals of NΦ(
K
) that are invariant under the subgroup
D
of all diagonal automorphisms. Connections between ideals of NΦ(
K
) and normal subgroups of the unipotent subgroup of the Chevalley group of the type Φ over
K
are used. Finally, we use methods of integral representation of sums and of listing lattice paths. We also discuss some other problems of the enumeration of ideals.
Towards the distributed processing of mobile software agents
Authors: Wang David K. , Wang James K.
Published: January 2007

The mobile software-agent paradigm allows the software agent's data or state to relocate from one machine to another. The actual executable code of the mobile software agent could migrate and not be constraint to a single machine or a specific operating environment. Currently, deficiency of open and close standards for mobile software-agents has contributed to the deterrent of its favorable public acceptance. Regardless, numerous efforts are emerging to standardize protocols and application programming interfaces, promising interoperability of mobile software-agents from various vendors. Contemporary development of organizations that focus on various commercial aspects of applied mobile software-agents could increase the public awareness and desire toward this novel technological investment.
A case for context-aware TCP/IP
Authors: Williamson Carey , Wu Qian
Published: January 2007

This paper discusses the design and evaluation of CATNIP, a Context-Aware Transport/Network Internet Protocol for the Web. This integrated protocol uses application-layer knowledge (i.e., Web document size) to provide explicit context information to the TCP and IP protocols. While this approach violates the traditional layered Internet protocol architecture, it enables informed decision-making, both at network endpoints and at network touters, regarding flow control, congestion control, and packet discard decisions.We evaluate the performance of the context-aware TCP/IP approach first using ns-2 network simulation, and then using WAN emulation to test a prototype implementation of CATNIP in the Linux kernel of an Apache Web server. The advantages of the CATNIP approach are particularly evident in a congested Internet with 1-10% packet loss. Simulation results indicate a 10-20% reduction in TCP packet loss using simple endpoint control mechanisms, with no adverse impact on Web page retrieval times. More importantly, using CATNIP context information at IP touters can reduce mean Web page retrieval times by 20-80%, and the standard deviation by 60-90%. The CATNIP algorithm can also interoperate with Random Early Detection (RED) for active queue management.
How much time do software professionals spend communicating?
Authors: Sullivan S. L.
Published: January 2007

How closely does the myth that programmers spend long hours working alone compare with reality? Not very much, according to the results of this study.
Environments: Austria compared to the United States
Authors: Couger J. D. , Adelsberger H.
Published: January 2007

The objective of the study was to analyze the motivation for computer personnel in Austria compared to the United States. A sample of more than 600 Austrian computer personnel was conducted, with the same diagnostic instruments used to derive a data base on motivation factors for 8,000 U.S. computer personnel. Seventeen Austrian organizations participated in the survey. The two survey populations were found to be quite similar in their rankings of motivation factors and in individual characteristics. Nevertheless, there was a mismatch for Austrian respondents on the two factors most important for motivation--individual need for growth as compared to the job's motivating capacity. A procedure for improving this match is discussed after the survey results are analyzed.
IRX: an information retrieval system for experimentation and user applications
Authors: Harman D. , Benson D. , Fitzpatrick L. , Huntzinger R. , Goldstein C.
Published: January 2007

IRX is a text retrieval system designed to be a testbed for conducting information retrieval research on statistically-based retrieval strategies in either batch or interactive modes. The modular structure of IRX has permitted major changes in components of the system (e.g., ranking algorithms, parsers, interfaces; without redesign. As an interactive system IRX is in use at the Johns Hopkins University and the Lister Hill Center providing access to databases in human and molecular genetics.
Recent results in mathematical modeling and performance evaluation of disks and disk array
Authors: Bachmat Eitan
Published: January 2007

In the seventies and eighties extensive work on mathematical modeling and performance evaluation of disks and disk arrays was carried out. The main tools were stochastic and combinatorial analysis. For the combinatorial approach led by C. K. Wong and his collaborators the reader is urged to consult [11]. for the stochastic approach led by E. G. Coffman and his collaborators one should consult [3]. Both references provide rather extensive bibliographies. In the late eighties and the nineties with the coming of the RAID "revolution", most of the work in the area has become rather heuristic in nature, see [5] for a survey, with a few notable exceptions.In this abstract we would like to report on two recent results which relate performance and modeling issues in disks and disk arrays to the theory of metric spaces and the theory of graph evolution and phase transition. We hope this will revive the spirit of the work done in the seventies and eighties (in other walks of life this may not be advisable). The results are taken from [2] and [4]
As we may communicate
Authors: Reynolds Carson
Published: January 2007

The purpose of this article is to critique and reshape one of the fundamental paradigms of Human-Computer Interaction: the workspace. This treatise argues that the concept of a workspace---as an interaction metaphor---has certain intrinsic defects. As an alternative, a new interaction model, the communication space is offered in the hope that it will bring user interfaces closer to the ideal of human-computer symbiosis.
XP requirement negotiation workshop
Authors: Fraser Steven , Succi Giancarlo
Published: January 2007

The plan is first to do an introduction with positions + interests and then to perform a visioning exercise.
An analysis of IS technical career paths and job satisfaction
Authors: Ridings Catherine M. , Eder Lauren B.
Published: January 2007

Technical career paths have been implemented in Information Systems (IS) departments to address the career development needs of employees whose career aspirations are not met by the traditional managerial career path. Understanding how to meet the needs of the technically oriented IS employee is important to IS career planning and development. Much has been written in both academic and popular literature about what composes a successful technical career path. Equity theory has been used in much of the existing research on technical career paths. This literature suggests that a successful technical career path should provide equitable rewards to those of a managerial career path. The present research establishes scales for four "key success factors" - equitable compensation, career path status, decision making influence, and career planning tool availability --- and examines the relationship of perceived equity of these factors to job satisfaction. Job satisfaction is relevant to an organization because it has been shown to be related to motivation to stay in an organization and organizational commitment. IS personnel on a technical career path were surveyed with regard to their equity perceptions and job satisfaction. Scales for the perception of equity for all four success factors were established. Data analysis showed that only the perception of equity of career planning tool availability is related to job satisfaction for these employees. Implications for management and areas for further research are discussed.
Weasel
Authors: Challis B. P. , Edwards A. D. N.
Published: January 2007

Although we constantly rely on touch and sound on a daily basis, product designers rarely monopolise the potential for auditory and, in particular, tactile feedback. This is particularly true within computer interface design where there is still a trend to work with highly graphical interfaces using only a mouse and a keyboard for input. This kind of kind of reliance on visual interaction actively prevents blind people from using many common computer applications. At the University of York we have been exploring possibilities for non-visual computer interaction with a view to establishing a set of design principles that can be used within multimodal interface design. To help with this, we have been developing an experimental non-visual multimodal approach to accessing music notation (called
Weasel
) which is aimed specifically at blind music learners.
Large-scale flow field visualization for aneurysm treatment
Authors: Liu Damon , Burgin Mark , Karplus Walter , Valentino Daniel
Published: January 2007

An important medical problem of the non-invasive treatment of brain aneurysm has attracted growing interest. Aneurysm surgery remains dangerous because surgeons have limited knowledge of blood flow patterns and complex 3D geometry of aneurysms. This information is essential to determine if the aneurysm is suitable for a certain surgical technique. Therefore, a Virtual Aneurysm (VA) research was initiated to make it possible for medical specialists to obtain such detailed information.Here we discuss two schemes relating to the realization and efficiency of VA system. The first is a scheme of data storage and management technique. It is aimed not only to achieve higher access efficiency and storage utilization but also to reduce the stress of memory resources. The second is the scheme of the branching simulation approach attempting to lessen the computational burden at visualization. These schemes illustrated by VA system, requiring minimal run-time computing or memory, are suggested so as to best exploit the performance for the simulation and visualization. While there is no intrinsic difference when applied to other scientific and engineering areas, these schemes are more beneficial to typical biomedical visualizations when the data already push the limits of the simulation and visualization environment.
Graph coloring in J
Authors: Peelle Howard A.
Published: January 2007

Fundamentals of graph coloring are introduced, and four basic alternative algorithms for coloring undirected graphs are described in J, along with programs for generating, adjacency matrices and testing them. Results are compared, and suggestions for future development are offered.
Is there a way of combining array-processing and object-oriented programming?
Authors: Reichard George
Published: January 2007

Based on the seven levels of principals of object-oriented programming described by B. Meyer [2], it is shown that with today's APL interpreters it is possible to combine array processing and object-oriented programming on a very high level of abstraction.
Artificial life evolution in a simplified APL2 environment
Authors: Alfonseca Manuel
Published: January 2007

Artificial life based on simulation evolution is a flourishing field. One of its most publicized achievements of the nineties was TIERRA, by T. S. Ray. APL2 has been used successfully to implement a similar simpler artificial life application that shows most of the interesting features of TIERRA in an efficient way, providing a modifiable environment where it is easy to experiment.
Representation of ASN.1 in APL nested structures
Authors: Hager Peter-Michael
Published: January 2007

Abstract Syntax Notation One, or ASN.1, is a standardized data format for data networks and open system communications, defined by the ITU. Several TCP/IP protocols and security applications are based on it. In order to use APL to implement software solutions in this field, we need tools that allow us to manipulate data in ASN.1 format. This presentation gives an overview of the ASN.1 encoding and describes a mechanism for transforming complex ASN.1 contents into APL nested structures and vice versa. The handling of security certificates using Dyalog APL is also discussed. In fact, it would be possible to extend APL could convert any objects even a whole workspace, to ASN.1.
Dyalog-APL application with threads on the basis of ActiveX data objects
Authors: Karabanov A. , Korablev J. , Roche G.
Published: January 2007

This paper presents an implementation of ActiveX Data Objects (ADO) in multithreading Dyalog-APL applications providing high performance access to any data source. The suggested approach is based upon an OLEClient object of Dyalog-APL that provides an OLE (Object Linking and Embedding) automation mechanism for working with ADO as an OLE Automation Server. This concept of such Dyalog-APL applications consists in a presentation of data-processing on 3 levels of hierarchy:{ {OPERATION)ε TASK}εJOB.A synchronisation of database operations in threads is supported by ADO events. Low level operations are accumulated in a library of functions that can also be used autonomously in a single thread for solution of private tasks. These functions are optimised to work in a Dyalog-APL environment. It is available to use in a root of a objects tree RECORDSET object. Data-processing can be carried out directly at a low level to optimise performance, other objects can be created when necessary for the solution of concrete tasks. Many of the RECORDSET operations can be notified before and after each other. OLE is very dependent on the Visual Basic programming language and the syntax of APL is more restricted than the syntax of Visual Basic. It is discussed accommodation problems from syntax point of view.
Avoiding the pitfalls of corporate intranets
Authors: Laurmaa Timo
Published: January 2007

This paper describes some typical problems experienced in corporate intranets and introduces a way to use XML in order to overcome these problems.A Dyalog APL implementation for intranet maintenance is used to illustrate how APL and XML work together.
High-level object oriented programming with array technology
Authors: Mougin Philippe
Published: January 2007

Although classical object-oriented programming languages provide high-level modeling capacities (abstract data type, inheritance etc.), they remain low-level relative to data manipulation. Addressing this problem with object oriented programming languages is an important mission of today's research. Considerable work has already been done, leading to the development of tools such as object query languages, with mixed results. In this paper, we present the key points of a new approach to this problem. We propose an enhancement of object oriented programming at the core level, by integrating Array Programming, a high-level model for computing. Our solution is based on an extension to object oriented programming. This integration of object technology and Array Programming allows for high-level object-oriented programming. At the same time, it opens Array Programming to the powerful world of objects.
An APL ompiler
Authors: Otto Tilman P.
Published: January 2007

Even if APL is the best-suited programming language for multi-dimensional data, nowadays computer applications additionally require complex graphical user interfaces, internet and database access. Combining software written in C, C++ or Java with interpreted APL programs is difficult. A homogeneous solution has been found by automatically converting APL programs into native C code. A complete APL2 like system including interpreter and session manager has been implemented in ISO C from scratch based on the standard C library. It is the property of the author and not yet commercially available. It has been successfully compiled on several operating systems. The built in system call
APL2C
allows one to compile any APL function including all referenced functions or operators within the workspace into native C code and completely removes the interpreter using direct calls to the C coded APL primitives. Only obvious restrictions (no runtime execution of character arrays or dynamic creation of functions via
FX
) apply. In addition, a makefile is created to enable the simple build of standalone executable files. The C files, generated by
APL2C,
can be easily mixed with other C/C++ source files and compiled on any platform provided that the required library for the APL primitives is available.
Spoken-word direction of computer program synthesis
Authors: Surkan Alvin J.
Published: January 2007

Prototype software is being designed to orchestrate speech-directed synthesis of customizable computer programs. The problems encountered are considered from a perspective that assumes the notation, syntax and function structure of
APL.
Program synthesis is to be completed with spoken-word dialogs between humans and computers. The computer is to assist in constructing programs with minimal or zero need for mechanical contact between mobile users and computer hardware. During synthesis, the system is to respond audibly and, only when necessary, visually. Spoken commands that invoke functions must be easily recognized in a limited vocabulary in a given context for interactively completing specification of each program. Experimentation with prototype system is expected to facilitate the replacement of conventional text-entry programming systems by that a practical one for speech-directed program synthesis and development.