ppxscal/embedding_network huggingface dataset:
Parallel Wavefront Algorithms Solving Lyapunov Equations for the Cholesky Factor on Message Passing Multiprocessors
Authors: José M. Claver
Venue: The Journal of Supercomputing (1999)

In this paper new parallel algorithms to solve the Lyapunov equations for the Cholesky factor using Hammarling&lsquo;s method on message passing multiprocessors are described. These algorithms are based on previous work carried out on the parallel solution of triangular linear systems by using row block data distribution and a wavefront of antidiagonals. The algorithms are theoretically analyzed and experimental results obtained on an SGI Power Challenge and a Cray T3D are presented.
A New Parallel and Distributed Shortest Path Algorithm for Hierarchically Clustered Data Networks
Authors: Shan Zhu, Garng M. Huang
Venue: IEEE Transactions on Parallel and Distributed Systems (1998)

This paper presents new efficient shortest path algorithms to solve single origin shortest path problems (SOSP problems) and multiple origins shortest path problems (MOSP problems) for hierarchically clustered data networks. To solve an SOSP problem for a network with n nodes, the distributed version of our algorithm reaches the time complexity of O(log(n)), which is less than the time complexity of O(log2(n)) achieved by the best existing algorithm [1]. To solve an MOSP problem, our algorithm minimizes the needed computation resources, including computation processors and communication links for the computation of each shortest path so that we can achieve massive parallelization. The time complexity of our algorithm for an MOSP problem is O(mlog(n)), which is much less than the time complexity of O(Mlog2(n)) of the best previous algorithm. Here, M is the number of the shortest paths to be computed and m is a positive number related to the network topology and the distribution of the nodes incurring communications. m is usually much smaller than M. Our experiment shows that m is almost a constant when the network size increases. Accordingly, our algorithm is significantly faster than the best previous algorithms to solve MOSP problems for large data networks.
Current accreditation, certification, and licensure activities related to software engineering
Authors: Nancy R. Mead, A. Joe Turner
Venue: Annals of Software Engineering (1999)

The issues associated with the accreditation, certification, and licensure of software engineers are, or at least should be, of great concern to the software engineering community. Perhaps as a result of publicity about safety&dash;critical software disasters in the news media, some state legislatures have considered regulating the practice of software engineering, and some professionals believe that accreditation, certification, and licensure are inevitable. Yet there is no agreed&dash;upon body of knowledge for software engineering on which to base accreditation, certification, or licensure, which makes implementing them difficult at best. In addition, it is not clear that these processes and possible mechanisms to support them are well understood within the software engineering community. This paper surveys how these three processes are conducted in other professions, summarizes the processes as they currently exist for computing in general, identifies some issues that are involved in implementing the processes for software engineering, and suggests possible actions that can be taken by the software engineering profession. The implications of accreditation, certification, and licensure for education are also discussed.
Work-Efficient Routing Algorithms for Rearrangeable Symmetrical Networks
Authors: Hasan Çam, José A. B. Fortes
Venue: IEEE Transactions on Parallel and Distributed Systems (1999)

The work performed by a parallel algorithm is the product of its running time and the number of processors it requires. This paper presents work-efficient (or cost-optimal) routing algorithms to determine the switch settings for realizing permutations on rearrangeable symmetrical networks such as Benes and the reduced $\Omega_N \Omega_N^{-1}$. These networks have $2n-1$ stages with $N= 2^n$ inputs/outputs, each stage consisting of $N/2$ crossbar switches of size ($2 \times 2 $). Previously known parallel routing algorithms for a rearrangeable network with $N$ inputs determine the states of all switches recursively in $O(n)$ iterations using $N$ processors. Each iteration determines the switch settings of at most two stages of the network and requires at least $O(n)$ time on a computer of $N$ processors, regardless of the type of its interconnection network. Hence, the work of any previously known parallel routing algorithm equals at least $O( N n^2 )$ for setting up all the switches of a rearrangeable network. The new routing algorithms run on a computer of $p$ processors, $1 \leq p \leq N/n$, and perform work $O(Nn)$. Moreover, because the range of $p$ is large, the new routing algorithms do not have to be changed in case some processors become faulty.
Pontryagin Maximum Principle for Optimal Control of Variational Inequalities
Authors: Maïtine Bergounioux, Housnaa Zidani
Venue: SIAM Journal on Control and Optimization (1999)

In this paper we investigate optimal control problems governed by variational inequalities. We present a method for deriving optimality conditions in the form of Pontryagin's principle. The main tools used are the Ekeland's variational principle combined with penalization and spike variation techniques.
Multidimensional Fuzzy Filtering using Statistical Parameters
Authors: A. Fotinos, N. Laskaris, G. Economou, S. Fotopoulos
Venue: Multidimensional Systems and Signal Processing (1999)

A multidimensional filtering technique is proposed using fuzzy logic ideas and based on two locally estimated statistical parameters. This technique is applied to the 3D space of color images. Two fuzzy sets for each fuzzy variable are considered. These fuzzy variables assign the corresponding part of the image to a specific class. The parameters of the fuzzy sets are derived in respect to the corresponding &rsquo;&rsquo;crisp&lsquo;&lsquo; sets attributed to the ideal noiseless image. An additional fuzzy selection process is also introduced by applying a distance dependent weighted average as the filtering action of each rule. Both signal and noise characteristics are taken into account in the filtering process. Experimental results show that these fuzzy non-linear filters work very well.
SimpleGraphics: Tcl/Tk visualization of real-time multi-threaded and distributed applications
Authors: Scott Arthur Moody, Samuel Kwok, Dale Karr
Venue: Proceedings of the ninth international workshop on Real-time Ada (1999)

Visualization of complex software applications is an exciting and challenging field. Useful displays are invaluable for developers in analysis of their software systems, and for meaningful system presentations to customers at a higher conceptual level.There have been many notable visualization examples applicable to data centric systems, including the GRASP code visualizer[11], the UW Illustrating Compiler[14], and the Information Space Visualizations embodied in Cone Trees[7] and Data Walls[8]. As conceptual and abstraction levels of these advanced graphics increases and becomes more prevalent, and as the real-world applications become more complicated from concurrency and distribution, the interfacing cohesion process becomes more difficult.This paper describes concepts and issues for integrating visualization techniques into multi-threaded and distributed applications, and shows foundation use available across application domains. SimpleGraphics is a term used in this paper to describe these powerful and rapidly developed visualizations applied to soft real-time applications. For the applications described here to meet the "simple" criteria they must be both conceptually simple and quickly developed - in say under 10 minutes. This leads to their use when appropriate in a "what if" manner, as well as taking them out if no longer needed. Looking ahead, the newer embedded devices, such as the AutoPC or the PalmPilot, have a small graphic foot print and will probably not allow for complicated graphics, leading to more use of abstractions like SimpleGraphics.Newer object oriented concurrency and distribution abstractions are being explored and applied to augment the work since the last International Real-Time Ada Workshop (IRTAW)[6][5]. With pervasive concurrent and distributed systems under development, it becomes clear that better controls and visualizations techniques are necessary, and Ada provides elegant solution techniques that can evolve with changing requirements. The graphic language, Tcl/Tk[9], is used here both for it's portability and its higher abstraction (through less syntax) supporting rapid development feedback.The benefits and impacts from this work include highlighting multi-threaded real-time issues, showing rapid turnaround through reuse, robust development through objects, better visualization techniques, and techniques for interfacing to other languages. In short, the goals of the 9th IRTAW are addressed in various aspects within this body of work.
Memory system behavior of Java programs: methodology and analysis
Authors: Jin-Soo Kim, Yarsun Hsu
Venue: ACM SIGMETRICS Performance Evaluation Review (2000)

This paper studies the memory system behavior of Java programs by analyzing memory reference traces of several SPECjvm98 applications running with a Just-In-Time (JIT) compiler. Trace information is collected by an exception-based tracing tool called JTRACE, without any instrumentation to the Java programs or the JIT compiler.First, we find that the overall cache miss ratio is increased due to garbage collection, which suffers from higher cache misses compared to the application. We also note that going beyond 2-way cache associativity improves the cache miss ratio marginally. Second, we observe that Java programs generate a substantial amount of short-lived objects. However, the size of frequently-referenced long-lived objects is more important to the cache performance, because it tends to determine the application's working set size. Finally, we note that the default heap configuration which starts from a small initial heap size is very inefficient since it invokes a garbage collector frequently. Although the direct costs of garbage collection decrease as we increase the available heap size, there exists an optimal heap size which minimizes the total execution time due to the interaction with the virtual memory performance.
ZPL: A Machine Independent Programming Language for Parallel Computers
Authors: Bradford L. Chamberlain, Sung-Eun Choi, E. Christopher Lewis, Calvin Lin, Lawrence Snyder, W. Derrick Weathersby
Venue: IEEE Transactions on Software Engineering (2000)

The goal of producing architecture-independent parallel programs is complicated by the competing need for high performance. The ZPL programming language achieves both goals by building upon an abstract parallel machine and by providing programming constructs that allow the programmer to ¿see¿ this underlying machine. This paper describes ZPL and provides a comprehensive evaluation of the language with respect to its goals of performance, portability, and programming convenience. In particular, we describe ZPL's machine-independent performance model, describe the programming benefits of ZPL's region-based constructs, summarize the compilation benefits of the language's high-level semantics, and summarize empirical evidence that ZPL has achieved both high performance and portability on diverse machines such as the IBM SP-2, Cray T3E, and SGI Power Challenge.
Approximation of the Wave and Electromagnetic Diffusion Equations by Spectral Method
Authors: F. Ben Belgacem, M. Grundmann
Venue: SIAM Journal on Scientific Computing (1998)

The aim of this paper is to describe a variational spectral solver of the three-dimensional operator (I + curl curl) which we often encounter when dealing with the Maxwell problem. We carry out a mathematical study proving the optimality of such an algorithm and we make an analysis of its complexity showing its efficiency. Finally, some applications to time-dependent partial differential equations obtained from the Maxwell model are presented.
Accelerating APL programs with SAC
Authors: Clemens Grelck, Sven-Bodo Scholz
Venue: Proceedings of the conference on APL '99 : On track to the 21st century: On track to the 21st century (1999)

The paper investigates, how SAC, a purely functional language based on C syntax, relates to APL in terms of expressiveness and run-time behavior. To do so, three different excerpts of real world APL programs are examined. It is shown that after defining the required APL primitives in SAC, the example programs can be re-written in SAC with an almost one-to-one correspondence. Run-time comparisons between interpreting APL programs and compiled SAC programs show that speedups due to compilation vary between 2 and 500 for three representative benchmark programs.
Eavesdropping games: a graph-theoretic approach to privacy in distributed systems
Authors: Matthew Franklin, Zvi Galil, Moti Yung
Venue: Journal of the ACM (JACM) (2000)

We initiate a graph-theoretic study of privacy in distributed environments with mobile eavesdroppers ("bugs"). For two privacy tasks&mdash;distributed database maintenance and message transmission&mdash;a computationally unbounded adversary &ldquo;plays an eavesdrpping game,&rdquo; coordinating the moment of the bugs among the sites to learn the current memory contents. Many different adversaries are considered, motivated by differences in eavesdropping technologies. We characterize the feasibility of the two privacy tasks combinatorially, construct protocols for the feasible cases, and analyze their computational complexity.
Area-Efficient VLSI Layouts for Binary Hypercubes
Authors: Alpesh Patel, Anthony Kusalik, Carl McCrosky
Venue: IEEE Transactions on Computers (2000)

The hypercube is an interesting and useful topology for parallel computation. While hypercubes have been analyzed in graph theory, this analysis has done little to determine the minimum area required for realizations of the hypercube topology on two-dimensional chips. In a common VLSI layout of the hypercube, the hypercube nodes are placed in a single-row in numeric order. This paper derives an easily computed formula for the minimum number of tracks used by this configuration. For an $n$-node hypercube, the number of tracks required is roughly two-thirds of $n$. This result is also a useful upper bound on the number of tracks required under optimal ordering. In general, the number of tracks required is a function of the ordering, but finding the optimal order (optimal in the sense of requiring the minimum number of tracks over all orderings) is NP-hard. Finally, the formula is applied to more area-efficient and practical two-dimensional hypercube layouts. In general, it allows estimation of and control over implementation parameters such as area and chip aspect ratios.
Learning Information Extraction Rules for Semi-Structured and Free Text
Authors: Stephen Soderland
Venue: Machine Learning (1999)

A wealth of on-line text information can be made available to automatic processing by information extraction (IE) systems. Each IE application needs a separate set of rules tuned to the domain and writing style. WHISK helps to overcome this knowledge-engineering bottleneck by learning text extraction rules automatically.WHISK is designed to handle text styles ranging from highly structured to free text, including text that is neither rigidly formatted nor composed of grammatical sentences. Such semi-structured text has largely been beyond the scope of previous systems. When used in conjunction with a syntactic analyzer and semantic tagging, WHISK can also handle extraction from free text such as news stories.
Embodiment in conversational interfaces: Rea
Authors: J. Cassell, T. Bickmore, M. Billinghurst, L. Campbell, K. Chang, H. Vilhjálmsson, H. Yan
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

In this paper, we argue for embodied corrversational characters as the logical extension of the metaphor of human - computer interaction as a conversation. We argue that the only way to fully model the richness of human I + to-face communication is to rely on conversational analysis that describes sets of conversational behaviors as fi~lfilling conversational functions, both interactional and propositional. We demonstrate how to implement this approach in Rea, an embodied conversational agent that is capable of both multimodal input understanding and output generation in a limited application domain. Rea supports both social and task-oriented dialogue. We discuss issues that need to be addressed in creating embodied conversational agents, and describe the architecture of the Rea interface.
Skill requirements of IT T professionals and graduates: an Australian study research-in-progress
Authors: Jo Orr, Liisa von Hellens
Venue: Proceedings of the 2000 ACM SIGCPR conference on Computer personnel research (2000)

The IT T (Information Technology and Telecommunications) Skills Taskforce recently released the results of their study on IT T skill requirements in Australia, predicting that in the current financial year, Australian employers will be seeking an excess of 30,000 skilled IT T professionals [8]. This figure is expected to grow at approximately 9% per year for at least the next 5 years [8]. Yet already, employers are reported to be experiencing difficulty obtaining skilled IT T personnel [8]. While the IT T Skills Task Forces study indicates IT T areas and specific IT T technical skills that are in demand, based on studies conducted in other nations, we suggest that this list is limited and not truly reflective of the skills an employer considers when making employment decisions. The objectives of this study are to 1.) determine the skill requirements of practicing IT T professionals in Australia, and to assess the relative importance of these skills; 2.) determine the skill requirements of IT T graduates in Australia, and to assess the relative importance of these skills; 3.) determine if and how the skill requirements of a practicing IT T professional differs from that of an IT T graduate; 4.) explore how the combination of skills is taken into account when hiring an IT T professional or graduate. To address this research problem, there are three methods of data collection being used in this study. Initially an analysis of IT T jobs advertised in Australian newspapers will be undertaken. The purpose of this analysis is to gain an insight into the current job market in Australia and the job skills being sought within this market. This is to be followed by the distribution of a questionnaire. The purpose of the questionnaire is to determine the skills required for IT T professionals and graduates, and to assess the relative importance of these skills. Finally, the questionnaires will be followed by interviews. The interviews will further support the identified skills required by IT T professionals and graduates, and the relative importance of these skills. More importantly however, the interviews will allow us to explore the combination of skills that are taken into account when employment decisions are being made.
OPTICS: ordering points to identify the clustering structure
Authors: Mihael Ankerst, Markus M. Breunig, Hans-Peter Kriegel, Jörg Sander
Venue: ACM SIGMOD Record (1999)

Cluster analysis is a primary method for database mining. It is either used as a stand-alone tool to get insight into the distribution of a data set, e.g. to focus further analysis and data processing, or as a preprocessing step for other algorithms operating on the detected clusters. Almost all of the well-known clustering algorithms require input parameters which are hard to determine but have a significant influence on the clustering result. Furthermore, for many real-data sets there does not even exist a global parameter setting for which the result of the clustering algorithm describes the intrinsic clustering structure accurately. We introduce a new algorithm for the purpose of cluster analysis which does not produce a clustering of a data set explicitly; but instead creates an augmented ordering of the database representing its density-based clustering structure. This cluster-ordering contains information which is equivalent to the density-based clusterings corresponding to a broad range of parameter settings. It is a versatile basis for both automatic and interactive cluster analysis. We show how to automatically and efficiently extract not only 'traditional' clustering information (e.g. representative points, arbitrary shaped clusters), but also the intrinsic clustering structure. For medium sized data sets, the cluster-ordering can be represented graphically and for very large data sets, we introduce an appropriate visualization technique. Both are suitable for interactive exploration of the intrinsic clustering structure offering additional insights into the distribution and correlation of the data.
Unpacking the semantics of source and usage to perform semantic reconciliation in large-scale information systems
Authors: Ken Smith, Leo Obrst
Venue: ACM SIGMOD Record (1999)

Semantic interoperability is a growing challenge in the United States Department of Defense (DoD). In this paper, we describe the basis of an infrastructure for the reconciliation of relevant, but semantically heterogeneous attribute values. Three types of information are described which can be used to infer the context of attributes, making explicit hidden semantic conflicts and making it possible to adjust values appropriately. Through an extended example, we show how an automated integration agent can derive the transformations necessary to perform four tasks in a simple semantic reconciliation.
Comparing random data allocation and data striping in multimedia servers
Authors: Jose Renato Santos, Richard R. Muntz, Berthier Ribeiro-Neto
Venue: Proceedings of the 2000 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (2000)

We compare performance of a multimedia storage server based on a random data allocation layout and block replication with traditional data striping techniques. Data striping techniques in multimedia servers are often designed for restricted workloads, e.g. sequential access patterns with CBR (constant bit rate) requirements. On the other hand, a system based on random data allocation can support virtually any type of multimedia application, including VBR (variable bit rate) video or audio, and interactive applications with unpredictable access patterns, such as 3D interactive virtual worlds, interactive scientific visualizations, etc. Surprisingly, our results show that system performance with random data allocation is competitive and sometimes even outperforms traditional data striping techniques, for the workloads for which data striping is designed to work best; i.e. streams with sequential access patterns and CBR requirements. Due to its superiority in supporting general workloads and competitive system performance, we believe that random data allocation will be the scheme of choice for next generation multimedia servers.
A constructivist approach to object-oriented design and programming
Authors: Said Hadjerrouit
Venue: Proceedings of the 4th annual SIGCSE/SIGCUE ITiCSE conference on Innovation and technology in computer science education (1999)

Computer science education is greatly affected by the object-oriented approach. This can be seen in the numerous new teachers being attracted to programming languages such as Java. Learning the object-oriented approach is however difficult for novice students, mostly because it requires a new way of thinking about computing and more depth to grasp. Thus, to promote the object-oriented approach at the introductory level, a re-examination of the teaching method is recommended. This article describes a pedagogical framework rooted in the constructivist epistemology for teaching object-oriented design and programming.