bluuebunny/crossref_metadata_2025 huggingface dataset:
How good is that data in the warehouse?
Authors: Artz John M.
Published: October 2004

A data warehouse is an analytical database used for decision support. Data are copied from production databases, cleaned up, and possibly renormalized (i.e., denormalized for performance or normalized to create correct record structures). If the resulting records are normalized incorrectly or if the users do not understand how the records have been denormalized, then a phenomenon called semantic disintegrity may occur. Semantic disintegrity occurs when a user submits a query and receives an answer, but the answer is not the answer to the question they believe that they asked.Thus an understanding of normalization is critically important for both database designers and database users. Unfortunately, the process of normalization relies on a series of heuristics that, in turn, assume the existence of an innate mental logic in the mind of the database designer or user for understanding data dependencies and their implications. The quality of answers derived from the data warehouse, in turn, relies on the existence of this innate mental logic.In order to determine if this is a reasonable assumption, an empirical test was constructed for the purpose of determining if subjects have an innate mental logic for understanding data dependencies and their implications.
Development of a measure to assess the quality of user-developed applications
Authors: Rivard Suzanne , Poirier Guylaine , Raymond Louis , Bergeron François
Published: October 2004

For several years now, software quality has been a major concern for those involved in the area of software engineering, and researchers as well as practitioners of the domain have proposed instruments to measure it. Application quality is also a concern for researchers and managers involved in the area of end-user computing. However, since end-user computing research is in a much earlier stage than research in software engineering, relatively few efforts have been made to assess the quality of user-developed applications. Building on earlier work in software engineering and in end-user computing, this study developed and assessed a measure of user-developed applications quality. The quality construct comprises eight dimensions: reliability, effectiveness, portability, economy, user-friendliness, understandability, verifiability, and maintainability. In turn, each quality dimension is composed of a set of criteria. Finally, each criterion is measured by a series of items. The instrument was tested by means of a survey involving 110 end-users. Confirmatory factor analysis, using the partial least squares technique, was conducted. The results indicate that the 56-items instrument is reliable and valid, and that it may be a useful tool for researchers and for practitioners alike.
A total quality management-based systems development process
Authors: Stylianou Antonis C. , Kumar Ram L. , Khouja Moutaz J.
Published: October 2004

Meaningful user involvement in systems development and an overall user orientation is critical to the success of any development project. Although traditional systems development methodologies recognize the importance of the user, they provide no formalized methods to translate user quality requirements into system design specifications. In addition, these methodologies are not rigorous in maintaining a focus on user quality requirements during the later phases of development.Manufacturing organizations with established Total Quality Management (TQM) programs successfully use a technique called Quality Function Deployment (QFD) to carry the customers' quality requirements through the design, production, and delivery processes. QFD has also been used to determine software requirements in systems development. This paper describes a systems development process that integrates QFD more completely into the traditional methodologies. The result is a practical process that focuses the development effort on system quality as defined by the various customer groups. An example case study illustrates the methodology and its benefits.
A model of organizational communications
Authors: Lind Mary R.
Published: October 2004

The study of organizational communications has proceeded without a widely accepted model. In this paper a framework of analysis for organizational communication is presented. It is based on the OSI model of data communication which was developed as a standard model to guide data communications systems development. The OSI model is composed of seven layers that each have responsibility for various aspects of data communications. Using this model as a guide, comparisons are made to an organizational communication network resulting in a model of organizational communications.
A manager's guide to integrated services digital network
Authors: Brancheau James C. , Naumann Justus D.
Published: October 2004

Large businesses are becoming increasingly dependent on telecommunications for their continued survival. A recent development in telecommunications which will have enormous strategic impact through the next decade is the concept of integrated services digital network (ISDN). ISDN's strategic value is tied to its goal of providing low cost voice, data, and video access to nearly every home and office in the United States, and eventually, the world. This paper describes what ISDN means and explores many of the issues surrounding its evolution, development, and potential use as a strategic weapon. To support the discussion of ISDN, the current public telecommunications network is described in some detail. Market and competitive forces, motivating and inhibiting the evolution toward ISDN are discussed with some observations on what the future may bring. Finally, planning considerations with respect to ISDN and its strategic implications for business are discussed.
Database schema design: an experimental comparison between normalization and information analysis
Authors: Shoval Peretz , Even-Chaime Moshe
Published: October 2004

This article compares two different methods for designing a data base schema-normalization and information analysis (IA). A set of design tasks was assigned to two groups of analysts who were trained to use the two methods in conjunction with the structured analysis method of system analysis. The results of the experiment revealed that the quality of the data base schemata designed using normalization was better than that designed using IA, that normalization required less time than IA to perform, and that the analysts preferred normalization.
Introducing client/server technologies in information systems curricula
Authors: Chaudhury Abhijit , Rao H. Raghav
Published: October 2004

One goal of information systems (IS) departments in business schools is to train IS professionals with the necessary technical skills to support the IS function in companies. This paper suggests that changes are needed for most current IS curricula to meet the technical requirements of the client/server (C/S) world of technologies. It is hoped that the ideas presented here will stimulate debate and discussions as to how this transition can be accomplished.
An application of rule-based and case-based reasoning within a single legal knowledge-based system
Authors: Pal Kamalendu , Campbell John A.
Published: October 2004

A knowledge-based system, Advisory Support for Home Settlement in Divorce (ASHSD), which gives advice on different aspects of matrimonial-home-settlement in English divorce law is described. The system employs two reasoning methods, rule-based reasoning (RBR) and case-based reasoning (CBR) in an integrated framework. It automates the estimation of the relative suitability of these reasoning methods for any given new case. This relative suitability is judged by matching the features of the selected best case and best rule against the new case. Standard methods of numerical taxonomy are used to determine which of the matches is best, and therefore whether a new case is better solved by calling on rules that express the usual legal knowledge in the area or by referring to a past case that has a interpretation of an ambiguous situation which rules fail to underpin.
Experimentations with TCP selective acknowledgment
Authors: Bruyeron Renaud , Hemon Bruno , Zhang Lixia
Published: October 2004

This paper reports our experimentation results with TCP Selective Acknowledgments (TCP-Sack), which became an Internet Proposed Standard protocol recently. To understand the performance impact of TCP-Sack deployment, in this study we examined the following issues:• How much performance improvement TCP-Sack may bring over the current TCP implementation, TCP-Reno. We conducted experiments both on a lab testbed and over the Internet, under various conditions of link delay and losses.• In particular, how well TCP-Sack may perform over long delay paths that include satellite links.• What is the performance impact of TCP connections with Sack options on those connections without Sack when the two types running in parallel, if there is any.
Deadlock control with Ada95
Authors: Levine Trudy
Published: October 2004

The Ada programming language is unique in its high-level concurrency facilities, supported by a secure and powerful set of programming constructs. Ada 95 now has additional capabilities, specifically the protected type construct.Although the Ada rendezvous is prone to deadlock, a careful discipline can ensure that this type of dead state does not occur. Restricting task communication assists in preventing deadlock, yet such restrictions may be too limiting and/or too inefficient for an application. Indeed, several researchers have suggested that deadlock should not be prevented, but monitored and corrected during testing and/or run time.This paper takes the position that deadlock should be prevented by following specific guidelines in the use of the rendezvous. We define deadlock, show how it can occur with Ada tasks, and outline mechanisms that are appropriate for its control.
A software engineering using Ada 95 course
Authors: Monroe Joseph , Yu H.
Published: October 2004

This paper presents a software engineering course titled "Software Engineering Using Ada 95" for undergraduate junior and senior levels. This course was developed under a Defense Information System Agency curriculum development grant support. In this course software methodology, object oriented techniques, CASE tools and the software development process are addressed. Ada 95 is also taught. Students are guided to design, implement, test and document various components and subsystems by using CASE tools. Four projects are designed that are either individual or team projects. By developing these projects students practice all steps of the software development process, various object oriented techniques, and integrate advanced features of Ada 95 into these system developments.This course covers all basic software engineering topics in the ACM/IEEE Computing Curriculum as well as part of advanced software engineering topics [3][5], trains students to be software engineers with experience in various industrial environments, guides students to practice using Ada 95 [2] and promotes Ada 95 applications. Therefore, this course is applied towards satisfying requirements for a B.S. degree in Computer Science, Computer Engineering, Software Engineering and Information Management.
Experience with control mechanisms for packet video in the internet
Authors: Bolot J-C. , Turletti T.
Published: October 2004

The single class best effort service available in the current Internet does not provide the guarantees, typically expressed in terms of minimum bandwidth and/or maximum delay or loss, associated with real-time applications such as live video. One way to support such applications in best effort networks is to use control mechanisms that adapt the coding, transmission, reception, and decoding processes at the source and at the destination(s) depending on the state of the network. In this paper, we examine and report on our experience over the past several years with such mechanisms for videoconferencing software. We illustrate our points with results obtained with the IVS software developed at INRIA.We consider in particular rate and error control mechanisms. These mechanisms adapt the bandwidth requirements and the resilience to packet loss of the video stream sent by a source coder. We have found that they do prevent video sources from swamping the resources of the Internet, and that they provide reasonably graceful degradation of image quality during periods of network congestion. However, they raise thorny issues of fairness with non-real time traffic sources (such as TCP sources) and of scalability for the multicast delivery of video in heterogeneous networks. We examine different approaches to tackling these problems.
Errata for “Potential benefits of delta encoding and data compression for HTTP”
Authors: Mogul Jeffrey C. , Douglis Fred , Feldmann Anja , Krishnamurthy Balachander
Published: October 2004

The quantitative results presented in our SIGCOMM '97 paper [1] include numerous minor errors. These errors were caused by programming bugs that led to faulty analyses and simulations, and by inaccurate transcriptions during the preparation of the paper. Here we present corrected figures and tables, as well as corrections to values that appeared in the text of the original paper. The effect of correcting the errors is to reduce the differences between the results based on the proxy trace and those based on the packet-level trace. Our overall conclusions are not significantly altered.
Bibliography of recent publications on computer communication
Authors: Steenstrup Martha
Published: October 2004

The quantitative results presented in our SIGCOMM '97 paper [1] include numerous minor errors. These errors were caused by programming bugs that led to faulty analyses and simulations, and by inaccurate transcriptions during the preparation of the paper. Here we present corrected figures and tables, as well as corrections to values that appeared in the text of the original paper. The effect of correcting the errors is to reduce the differences between the results based on the proxy trace and those based on the packet-level trace. Our overall conclusions are not significantly altered.
The DGSA: unmet information security challenges for operating system designers
Authors: Feustel Edward A. , Mayfield Terry
Published: October 2004

The Department of Defense (DoD) Goal Security Architecture (DGSA) introduces a broader view of information security from that previously held by the Department, one which has much more in common with the requirements of an inter-networked commercial view of information security. The purpose of this paper is to introduce designers of operating systems to the most important aspects of the DGSA conceptual framework in order to open discussions on both the suitability of the framework and the feasibility of its implementation. The rationale for this framework is discussed in this paper. Challenging aspects of implementation are presented, and areas needing refinement prior to operating system implementation are described.Work supported by the National Security Agency and the Defense Information Systems Agency under contract number DASW01-94-C-0054. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of Defense or the U.S. Government.
System support for partition-aware network applications
Authors: Babaoğlu Özalp , Davoli Renzo , Montresor Alberto , Segala Roberto
Published: October 2004

Network applications and services need to be
environment-aware
in order to meet quality-of-service requirements in an increasingly dynamic world. In this paper we consider
partition awareness
as an instance of environment awareness in network applications that need to be reliable and self-managing. Partition-aware applications dynamically reconfigure themselves and adjust the quality of their services in response to network partitions and merges. As such, they can automatically adapt to changes in the environment and remain available in multiple partitions with perhaps degraded or reduced services, but without blocking. We propose a system layer consisting of group membership and reliable multicast services that provides systematic support for partition-aware application development. We illustrate the effectiveness of the proposed interface by solving three problems that represent different classes of realistic network applications.
Quality of service based routing
Authors: Apostolopoulos George , Guérin Roch , Kamat Sanjay , Tripathi Satish K.
Published: October 2004

Recent studies provide evidence that Quality of Service (QoS) routing can provide increased network utilization compared to routing that is not sensitive to QoS requirements of traffic. However, there are still strong concerns about the increased cost of QoS routing, both in terms of more complex and frequent computations and increased routing protocol overhead. The main goals of this paper are to study these two cost components, and propose solutions that achieve good routing performance with reduced processing cost. First, we identify the parameters that determine the protocol traffic overhead, namely (a) policy for triggering updates, (b) sensitivity of this policy, and (c) clamp down timers that limit the rate of updates. Using simulation, we study the relative significance of these factors and investigate the relationship between routing performance and the amount of update traffic. In addition, we explore a range of design options to reduce the processing cost of QoS routing algorithms, and study their effect on routing performance. Based on the conclusions of these studies, we develop extensions to the basic QoS routing, that can achieve good routing performance with limited update generation rates. The paper also addresses the impact on the results of a number of secondary factors such as topology, high level admission control, and characteristics of network traffic.
Secure group communications using key graphs
Authors: Wong Chung Kei , Gouda Mohamed , Lam Simon S.
Published: October 2004

Many emerging applications (e.g., teleconference, real-time information services, pay per view, distributed interactive simulation, and collaborative work) are based upon a group communications model, i.e., they require packet delivery from one or more authorized senders to a very large number of authorized receivers. As a result, securing group communications (i.e., providing confidentiality, integrity, and authenticity of messages delivered between group members) will become a critical networking issue.In this paper, we present a novel solution to the scalability problem of group/multicast key management. We formalize the notion of a secure group as a triple (
U,K,R
) where
U
denotes a set of users,
K
a set of keys held by the users, and
R
a user-key relation. We then introduce key graphs to specify secure groups. For a special class of key graphs, we present three strategies for securely distributing rekey messages after a join/leave, and specify protocols for joining and leaving a secure group. The rekeying strategies and join/leave protocols are implemented in a prototype group key server we have built. We present measurement results from experiments and discuss performance comparisons. We show that our group key management service, using any of the three rekeying strategies, is scalable to large groups with frequent joins and leaves. In particular, the average measured processing time per join/leave increases linearly with the logarithm of group size.
Achieving bounded fairness for multicast and TCP traffic in the Internet
Authors: Wang Huayan Amy , Schwartz Mischa
Published: October 2004

There is an urgent need for effective multicast congestion control algorithms which enable reasonably fair share of network resources between multicast and unicast TCP traffic under the current Internet infrastructure. In this paper, we propose a quantitative definition of a type of bounded fairness between multicast and unicast best-effort traffic, termed "essentially fair". We also propose a window-based Random Listening Algorithm (RLA) for multicast congestion control. The algorithm is proven to be essentially fair to TCP connections under a restricted topology with equal round-trip times and with phase effects eliminated. The algorithm is also fair to multiple multicast sessions. This paper provides the theoretical proofs and some simulation results to demonstrate that the RLA achieves good performance under various network topologies. These include the performance of a generalization of the RLA algorithm for topologies with different round-trip times.
Uniform versus priority dropping for layered video
Authors: Bajaj Sandeep , Breslau Lee , Shenker Scott
Published: October 2004

In this paper, we analyze the relative merits of uniform versus priority dropping for the transmission of layered video. We first present our original intuitions about these two approaches, and then investigate the issue more thoroughly through simulations and analysis in which we explicitly model the performance of layered video applications. We compare both their performance characteristics and incentive properties, and find that the performance benefit of priority dropping is smaller than we expected, while uniform dropping has worse incentive properties than we previously believed.
Predictive and adaptive bandwidth reservation for hand-offs in QoS-sensitive cellular networks
Authors: Choi Sunghyun , Shin Kang G.
Published: October 2004

How to control hand-off drops is a very important Quality-of-Service (QoS) issue in cellular networks. In order to keep the hand-off dropping probability below a pre-specified target value (thus providing a
probabilistic
QoS guarantee), we design and evaluate
predictive
and
adaptive
schemes for the bandwidth reservation for the existing connections' handoffs and the admission control of new connections.We first develop a method to estimate user mobility based on an aggregate history of hand-offs observed in each cell. This method is then used to predict (probabilistically) mobiles' directions and hand-off times in a cell. For each cell, the bandwidth to be reserved for hand-offs is calculated by estimating the total sum of fractional bandwidths of the expected hand-offs within a mobility-estimation time window. We also develop an algorithm that controls this window for efficient use of bandwidth and effective response to (1) time-varying traffic/mobility and (2) inaccuracy of mobility estimation. Three different admission-control schemes for new connection requests using this bandwidth reservation are proposed. Finally, we evaluate the performance of the proposed schemes to show that they meet our design goal and outperform the static reservation scheme under various scenarios.
High-speed policy-based packet forwarding using efficient multi-dimensional range matching
Authors: Lakshman T. V. , Stiliadis D.
Published: October 2004

The ability to provide differentiated services to users with widely varying requirements is becoming increasingly important, and Internet Service Providers would like to provide these differentiated services using the same shared network infrastructure. The key mechanism, that enables differentiation in a connectionless network, is the packet classification function that parses the headers of the packets, and after determining their context, classifies them based on administrative policies or real-time reservation decisions. Packet classification, however, is a complex operation that can become the bottleneck in routers that try to support gigabit link capacities. Hence, many proposals for differentiated services only require classification at lower speed edge routers and also avoid classification based on multiple fields in the packet header even if it might be advantageous to service providers. In this paper, we present new packet classification schemes that, with a worst-case and traffic-independent performance metric, can classify packets, by checking amongst a few thousand filtering rules, at rates of a million packets per second using range matches on more than 4 packet header fields. For a special case of classification in two dimensions, we present an algorithm that can handle more than 128K rules at these speeds in a traffic independent manner. We emphasize worst-case performance over average case performance because providing differentiated services requires intelligent queueing and scheduling of packets that precludes any significant queueing before the differentiating step (i.e., before packet classification). The presented filtering or classification schemes can be used to classify packets for security policy enforcement, applying resource management decisions, flow identification for RSVP reservations, multicast look-ups, and for source-destination and policy based routing. The scalability and performance of the algorithms have been demonstrated by implementation and testing in a prototype system.
Summary cache
Authors: Fan Li , Cao Pei , Almeida Jussara , Broder Andrei Z.
Published: October 2004

The sharing of caches among Web proxies is an important technique to reduce Web traffic and alleviate network bottlenecks. Nevertheless it is not widely deployed due to the overhead of existing protocols. In this paper we propose a new protocol called "Summary Cache"; each proxy keeps a summary of the URLs of cached documents of each participating proxy and checks these summaries for potential hits before sending any queries. Two factors contribute to the low overhead: the summaries are updated only periodically, and the summary representations are economical --- as low as 8 bits per entry. Using trace-driven simulations and a prototype implementation, we show that compared to the existing Internet Cache Protocol (ICP), Summary Cache reduces the number of inter-cache messages by a factor of 25 to 60, reduces the bandwidth consumption by over 50%, and eliminates between 30% to 95% of the CPU overhead, while at the same time maintaining almost the same hit ratio as ICP. Hence Summary Cache enables cache sharing among a large number of proxies.
Error control techniques for interactive low-bit rate video transmission over the Internet
Authors: Rhee Injong
Published: October 2004

A new retransmission-based error control technique is presented that does not incur any additional latency in frame playout times, and hence are suitable for interactive applications. It takes advantage of the motion prediction loop employed in most motion compensation-based codecs. By correcting errors in a reference frame caused by earlier packet loss, it prevents error propagation. The technique rearranges the temporal dependency of frames so that a displayed frame is referenced for the decoding of its succeeding dependent frames much later than its display time. Thus, the delay in repairing lost packets can be effectively masked out. The developed technique is combined with layered video coding to maintain consistently good video quality even under heavy packet loss. Through the results of extensive Internet experiments, the paper shows that layered coding can be very effective when combined with the retransmission-based error control technique for low-bit rate transmission over best effort networks where no network-level mechanism exists for protecting high priority data from packet loss.
Modeling TCP throughput
Authors: Padhye Jitendra , Firoiu Victor , Towsley Don , Kurose Jim
Published: October 2004

In this paper we develop a simple analytic characterization of the steady state throughput, as a function of loss rate and round trip time for a bulk transfer TCP flow, i.e., a flow with an unlimited amount of data to send. Unlike the models in [6, 7, 10], our model captures not only the behavior of TCP's fast retransmit mechanism (which is also considered in [6, 7, 10]) but also the effect of TCP's timeout mechanism on throughput. Our measurements suggest that this latter behavior is important from a modeling perspective, as almost all of our TCP traces contained more time-out events than fast retransmit events. Our measurements demonstrate that our model is able to more accurately predict TCP throughput and is accurate over a wider range of loss rates.
Computational geometry column 33
Authors: O'Rourke Joseph
Published: October 2004

Several recent SIGGRAPH papers on surface simplification are described.
Everything you wanted to know about the running time of Mergesort but were afraid to ask
Authors: Parberry Ian
Published: October 2004

Although mergesort is an algorithm that is frequently glossed over in textbooks, it provides fertile ground for planting ideas about algorithm analysis in the minds of students. Why can we assume that
n
is a power of 2? How big is the increase in constant multiple if we do? And how do we analyze it if we
don't
? Here then is an excruciatingly detailed analysis of mergesor t for the student whose enquiring mind truly wants to know.
Guidance for the use of the Ada programming language in high integrity systems
Authors: Wichmann B. A.
Published: October 2004

This paper is the current result of a study by the ISO HRG Rapporteur group which is being circulated for comment. Many people have contributed to this, but those who have either attended two recent meetings of group or have made substantial e-mail comments are: Praful V Bhansali (Boeing, USA), Alan Burns (University of York, UK), Bernard Carre' (Praxis Critical Systems, UK), Dan Craigen (ORA, Canada), Nick Johnson MoD, UK), Stephen Michell (Canada), Gilles Motet (DGEI/INSA, France), George Romanski (AONIX, USA), Mark Saaltink (ORA, Canada), Gareth Rowlands (MoD, UK), Adam Tacy (MoD, UK), (Phil) JP Thornley (BAe, UK), David Tombs (DERA, UK), Tullio Vardanega (ESA/ESTEC, Netherlands), Brian Wichmann (NPL, UK).
Dispatching on the function result
Authors: Ben-Ari Mordechai
Published: October 2004

This paper is a tutorial on dynamic dispatching of functions with a controlling result. A case shows how to use this construct to replicate a value extracted from a heterogeneous data structure.
Tasking solutions to the Sieve of Eratosthenes
Authors: Collins W. Robert
Published: October 2004

Shapiro and later Bokhari described a multiprocessing view of the Sieve of Eratosthenes, to test load balancing on shared-memory multiprocessors. Shapiro proposed the following parallel version of the sieve:Eratosthenes starts off with a large number of slaves and instructs the first one to write down the integers 2, 3, 4, … on the ground in a field. A second slave is dispatched with instructions to cross out all multiples of 2. Eratosthenes now moves down the "list" of numbers and dispatches a new slave whenever an uncrossed number is encountered. Thus, the third slave is sent off with instructions to cross out the multiples of 3, the fourth crosses out all multiples of 5, and so on. The uncrossed numbers that remain at the end of this process are the primes.It turns out that Ada (especially Ada95) supports multiprocessing well in the Sieve of Eratosthenes. One may make use of static and dynamic tasks, protected types, communication, and synchronization in a relatively small program, making the sieve an excellent choice for instruction. In a graduate course we offer at William & Mary, Theory of Programming Languages, we give students a multiprocessing assignment. At this stage, students have rarely done parallel programming, except for low-level threads and locks in operating systems courses. So a parallel programming assignment in a high level language adds an extra tool to their arsenals and gives them an idea of an important part of computing today.
ASIS Report for WG9 Meeting on 12 June 1998, Uppsala, Sweden
Authors: Blake Stephen , Roby Clyde G. , Colket William Currie
Published: October 2004

This report covers the ASIS activities since the last ISO/IEC JTC1/SC22 WG9 meeting on 14 November 1997 in St. Louis, Missouri; United States.
A comparison of Ada and Java as a foundation teaching language
Authors: Brosgol Benjamin M.
Published: October 2004

Java has entered the software arena in unprecedented fashion, upstaging languages and technologies that are longstanding players in the industry. Almost unheard of before 1995, the language and its surrounding technology are attracting increasing attention not merely in the hardware and software communities but also among lay users and in the popular press. This phenomenon has not escaped the attention of academia, and a growing number of colleges and universities are looking at Java as a candidate "foundation" language on which to base computer science curricula.This paper looks at the role of a programming language for teaching computer science courses and compares Ada and Java against the identified criteria. It concludes that Ada is the superior choice, based on technical factors such as its more comprehensive feature set and its methodology-neutral design, and also taking into account external factors including the availability of good but inexpensive compilation environments.Section 1 provides a brief overview of the Java technology. Section 2 identifies the criteria relevant to choosing a programming language for a foundation-level Computer Science course. Section 3 compares Ada and Java with respect to the criteria related to technical aspects of the language, and Section 4 compares the languages with respect to external factors. Section 5 summarizes the conclusions of this analysis.Appendix A furnishes a summary of the Java language. It is assumed that the reader is familiar with Ada, and thus an Ada language summary is not included. Web sites with links to Ada information include [SIGAda], [Kempe
1
], and [AdaIC].
A software engineering training program for non-software engineers
Authors: Heinfeld Blaine W. , Silver James L.
Published: October 2004

This paper describes a software engineering training program that targets personnel with skills in other engineering disciplines. This intensive nine-week program was designed in the fall of 1995. It was offered three times during 1996 and 1997 with modifications that incorporate lessons learned from previous sessions. We will describe key features of the program, give an overview of its implementation, report on our experiences with graduates of the program, and note lessons learned.
FrameKit, an Ada framework for a fast implementation of CASE enviroments
Authors: Kordon Fabrice , Mounier Jean-Luc
Published: October 2004

Software engineering methodologies rely on various and complex graphical representations and are more useful when associated to CASE (Computer Aided Software Engineering) tools designed to take care of constraints that have to be respected. Now, CASE tools gave way to CASE environments (a set of tools that have a strong coherence in their us). This concept provides enhanced solutions for software reusability while the environment may be adapted to a specific understanding of a design methodology.This paper describes FrameKit, an Ada based framework dedicated to the quick implementation of CASE environments. We summarize first the concepts implemented in FrameKit and illustrate them using a detailed example of a simple tool implementation and integration.
Concurrency in object-oriented propagation modeling using Ada95
Authors: Needham Donald M. , Demurjian Steven A. , McMahon Margaret M.
Published: October 2004

Modeling object interdependency within an object-oriented application requires design-time mechanisms for specifying object interrelationships, as well as software constructs for the runtime maintenance of these relationships. In this paper, we present our technique for the design-time modeling of
propagations
(our term for the relationships between interdependent objects), with a focus on the concurrently executing portions of our propagation model. We examine our propagation model as implemented using Ada95's tasking constructs, and present the source level mechanisms through which our model achieves concurrency. The concurrency embedded within our approach to propagation modeling allows the development of software applications that more fully utilize environments supportive of multi-tasking.
Teaching computer networks through modeling
Authors: Davis Noël , Ransbottom Scot , Hamilton Drew
Published: October 2004

Modern computer scientists need to understand both the theoretical and practical aspects of computer networking. As computer science teaching methods continue to mature, experiences in mixing theory and application have been shared in the community [Marti 96]. While the literature is rich with experiences in applied or project based courses in artificial intelligence, architecture, software engineering, data structures and algorithms, few have addressed the challenge of coordinating theory and practice in computer networking courses.Combining theory and practice in a single course on computer networks is difficult because of the complexity and scale of modern networks. Classroom modeling of networks is a technique to illustrate the theoretical aspects of networking through practical models of computer networks. At West Point we are evolving our network course to use network modeling and simple simulation as a visualization tool to show how networks operate and the performance tradeoffs associated with network design decisions. This approach provides the opportunity to do more than teach an undergraduate survey course in computer networking.
Master of science in software engineering via distance learning
Authors: Shing M. , Berzins V. , Holden M. , Eagle C. , Luqi
Published: October 2004

This paper describes the distance learning Software Engineering Master's program offered at the Naval Postgraduate School and presents the lessons from its first class. The program differs from the other software engineering programs in two ways: (1) the curriculum is developed specifically to meet the needs for formal software engineering education for DoD software practitioners with an undergraduate computer science degree and at least two years of software experience, and (2) the program is offered totally via distance learning. The curriculum builds upon the students' scientific knowledge in computer science from their undergraduate education and the insight into software problems from their working experience. It introduces students to a set of engineering practices that enable ordinary practitioners to create sophisticated software systems that work, and teaches students the principles and methods for managing the software development processes.
New ideas for generic components in Ada
Authors: Riehle Richard
Published: October 2004

The creation of reusable software components is an important part of modern software practice. Generic templates are one technique for designing these components. A generic template is a module containing algorithms which can operate on some class of data types where the specific data type is not known until later in the development process. Many languages, including Ada, support this technique. In Ada, generic templates must be type-safe at compile time. We examine some features of Ada which allow us to define the type as an entire package module and to instantiate with that module. The main theme of this paper will be generic formal package parameters.
RT PC distributed services overview
Authors: Sauer Charles H. , Johnson Don W. , Loucks Larry K. , Shaheen-Gouda Amal A. , Smith Todd A.
Published: October 2004

RT PC Distributed Services
provides distributed operating system capabilities for the AIX
1
operating system. These include distributed files with local/remote transparency, a form of "single system image" and distributed interprocess communication. Applications, including data management/data base applications, can typically be used in the distributed environment without modification to existing
object
code. Distributed Services is architected for strong compatibility with AIX, the UNIX
2
operating system, IBM architectures such as SNA and some of the architectures of Sun Microsystems'
3
NFS. The Distributed Services implementation includes caching mechanisms and other algorithms designed for high performance without sacrificing strict functional transparency. This paper describes the key characteristics and decisions in the design of Distributed Services.
PAMAS—power aware multi-access protocol with signalling for ad hoc networks
Authors: Singh Suresh , Raghavendra C. S.
Published: October 2004

In this paper we develop a new multiaccess protocol for ad hoc radio networks. The protocol is based on the original MACA protocol with the adition of a separate signalling channel. The unique feature of our protocol is that it conserves battery power at nodes by intelligently powering off nodes that are not actively transmitting or receiving packets. The manner in which nodes power themselves off does not influence the delay or throughput characteristics of our protocol. We illustrate the power conserving behavior of PAMAS via extensive simulations performed over ad hoc networks containing 10-20 nodes. Our results indicate that power savings of between 10% and 70% are attainable in most systems. Finally, we discuss how the idea of power awareness can be built into other multiaccess protocols as well.
Adaptive VBR video traffic management for higher utilization of ATM networks
Authors: Chiruvolu Girish , Sankar Ravi , Ranganathan N.
Published: October 2004

The VBR video traffic exhibits high burstiness and correlation properties that are quite complex to be captured by a single traffic model. Efficient resource management based on few parameters of the source traffic is highly desirable. The real-time VBR video traffic has stringent quality of service (QoS) requirements such as delay (few milliseconds) and cell loss (1 in 10
-5
) that are difficult to achieve with good utilization (> 0.6) by static bandwidth allocation schemes. In order to satisfy such QoS constraints with good utilization, proper adaptive mechanisms have to be devised. This paper presents a dynamic bandwidth allocation scheme for VBR video traffic based on buffer monitoring and a simple LMS (least mean square) traffic prediction system. The goal is to reduce the frequency of the bandwidth reallocations and at the same time reduce the Cell-loss Ratio (CLR) with increased utilization. Simulation results indicate that utilization up to 0.8 can be achieved by the proposed scheme even under high source alignment [26] for bursty VBR video traffic. It is found that the proposed adaptive scheme outperforms the static FCFS allocation scheme with lower buffer requirements and fewer (< 5%) bandwidth reallocations.
An evaluation of TCP with larger initial windows
Authors: Allman Mark , Hayes Chris , Ostermann Shawn
Published: October 2004

TCP's slow start algorithm gradually increases the amount of data a sender injects into the network, which prevents the sender from overwhelming the network with an inappropriately large burst of traffic. However, the slow start algorithm can make poor use of the available bandwidth for transfers which are small compared to the bandwidth-delay product of the link, such as file transfers up to few thousand characters over satellite links or even transfers of several hundred bytes over local area networks. This paper evaluates a proposed performance enhancement that raises the initial window used by TCP from 1 MSS-sized segment to roughly 4 KB. The paper evaluates the impact of using larger initial windows on TCP transfers over both the shared Internet and dialup modem links.
A comparative investigation of ethical decision making
Authors: Cappel James J. , Windsor John C.
Published: October 2004

As information technology evolves, it continues to raise new ethical challenges. In recognition of this, the business and academic communities have focused increased attention on ethics. Professional codes of ethics have been enacted by the ACM, AITP, and other computing organizations to provide guidance to information systems (IS) professionals in resolving ethical dilemmas. In addition, the IS'95 model curriculum and the American Assembly of Collegiate Schools of Business (AACSB) guidelines for business education both recognize the importance of ethics in business educational programs.This paper explores an important question that has been neglected by previous research: do IS professionals differ significantly from students in terms of their perceptions about ethical issues? Two studies were conducted and they revealed a number of ethical decision-making differences between professionals and students. This result, along with an additional finding that participants showed little consensus about most ethical scenarios, suggests that ethical decision making is often difficult and that both students and professionals can benefit from ethical training and education. The findings also have important implications for IS research.
Revisiting the perennial question
Authors: Wynekoop Judy L. , Walz Diane B.
Published: October 2004

Three types of information systems personnel (programmers, systems analysts, and project managers) were compared to the general population based on responses to a standardized personality test. The IS professionals, in aggregate, exceeded population norms for nearly all of the relevant scales, confirming much prior research.However, the personality profiles of analysts and managers differed widely from that of programmers, but not from one another. Managers and analysts were found to be conservative, logical, analytical, diligent, and ambitious, with strong leadership tendencies and high self-confidence and self-esteem. They were also found to be more sociable and creative than in past research.The differences identified between traditional programmers and systems analysts and managers indicate the importance of studying, managing, and recruiting these groups differently. The findings offer insight into how to retain, promote, and manage IS personnel effectively.
Techniques for authentication protocols and key distribution on wireless ATM networks
Authors: Patiyoot D. , Shepherd S. J.
Published: October 2004

With the growing acceptance of ATM as the standard for broadband networking and the increasing importance of wireless devices, it has become appropriate to extend ATM application to wireless platforms. Adding a wireless network to existing wired network creates a set of problems. Security functions have to be reconsidered since wired network security did not account for the open medium, mobile roaming. A necessary foundation for securing a network is the ability to authenticate entities. There is a need to authenticate users of the system so that the resources would not be misused by nonsubscribers. After authentication by authentication protocol, two parties who involves in communications should be able and entitle to believe that they are communicating with each other and not with intruders. In mobile networks, normally secret-key cryptography is used for authentication. In this paper, both secret key and public key are attempted to be used in wireless ATM network.