ppxscal/embedding_network huggingface dataset:
The Set of 2-by-3 Matrix Pencils --- Kronecker Structures andtheir Transitions Under Perturbations
Authors: Erik Elmroth, Bo Kagstrom
Venue: SIAM Journal on Matrix Analysis and Applications (1996)

The set (or family) of 2-by-3 matrix pencils $A - \lambda B$ comprises 18 structurally different Kronecker structures (canonical forms). The algebraic and geometric characteristics of the generic and the 17 nongeneric cases are examined in full detail. The complete closure hierarchy of the orbits of all different Kronecker structures is derived and presented in a closure graph that shows how the structures relate to each other in the 12-dimensional space spanned by the set of 2-by-3 pencils. Necessary conditions on perturbations for transiting from the orbit of one Kronecker structure to another in the closure hierarchy are presented in a labeled closure graph. The node and arc labels shows geometric characteristics of an orbit's Kronecker structure and the change of geometric characteristics when transiting to an adjacent node, respectively. Computable normwise bounds for the smallest perturbations $(\delta A, \delta B)$ of a generic 2-by-3 pencil $A - \lambda B$ such that $(A + \delta A) - \lambda (B + \delta B)$ has a specific nongeneric Kronecker structure are presented. First, explicit expressions for the perturbations that transfer $A - \lambda B$ to a specified nongeneric form are derived. In this context tractable and intractable perturbations are defined. Second, a modified GUPTRI that computes a specified Kronecker structure of a generic pencil is used. Perturbations devised to impose a certain nongeneric structure are computed in a way that guarantees one will find a Kronecker canonical form (KCF) on the closure of the orbit of the intended KCF. Both approaches are illustrated by computational experiments. Moreover, a study of the behaviour of the nongeneric structures under random perturbations in finite precision arithmetic (using the GUPTRI software) show for which sizes of perturbations the structures are invariant and also that structure transitions occur in accordance with the closure hierarchy. Finally, some of the results are extended to the general $m$-by-$(m+1)$ case.
The $p$-Product and its Applications in Signal Processing
Authors: Huixia Zhu, Gerhard X. Ritter
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

This paper introduces a new matrix product that proves useful in the representation of a large class of orthogonal transforms. It is shown that transform representation in terms of this product provides novel computational methods for computing the fast Fourier transform, the fast Walsh transform, a fast generalized Walsh transform, as well as a fast wavelet transform. Uniqueness and the advantages of this new formalism over traditional methods are also discussed.
Deducing fairness properties in UNITY logic&mdash;a new completeness result
Authors: Yih-Kuen Tsay, Rajive L. Bagrodia
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1995)

We explore the use of UNITY logic in specifying and verifying fairness properties of UNITY and UNITY-like programs whose semantics can be modeled by weakly fair transition systems. For such programs, strong fairness properties in the form of &ldquo;if p holds infinitely often then q also holds infinitely often &square;&loz;p&rArr;&square;&loz;q , can be expressed as conditional UNITY properties of the form of &ldquo;Hypothesis: true&rarr;p Conclusion:true&rarr;q &rdquo;. We show that UNITY logic is relatively complete for proving such properties; in the process, a simple inference rule is derived. Specification and verification of weak fairness properties are also discussed.
A semester project for CS1
Authors: Catherine C. Bareiss
Venue: ACM SIGCSE Bulletin (1996)

While much work has been done on the lab component of the CS1 course, programming assignments have not received as much attention. Many CS1 courses have a series of programming assignments that supplement the lab component. However, the assignments are often unrelated to each other. While the advantages of semester project for upper division courses are well known, little has been done on the use of a semester project in the first programming course. However, it is feasible for a first semester programmer to complete an entire semester project if it is designed properly. The development of a semester-long programming project done in phases has many benefits to offer a CS1 course.
Algorithm 744: a stochastic algorithm for global optimization with constraints
Authors: F. Michael Rabinowitz
Venue: ACM Transactions on Mathematical Software (TOMS) (1995)

A stochastic algorithm is presented for finding the global optimum of a function of n variables subject to general constraints. The algorithm is intended for moderate values of n, but it can accommodate objective and constraint functions that are discontinuous and can take advantage of parallel processors. The performance of this algorithm is compared to that of the Nelder-Mead Simplex algorithm and a Simulated Annealing algorithm on a variety of nonlinear functions. In addition, one-, two-, four-, and eight-processor versions of the algorithm are compared using 64 of the nonlinear problems with constraints collected by Hock and Schittkowski. In general, the algorithm is more robust than the Simplex algorithm, but computationally more expensive. The algorithm appears to be as robust as the Simulated Annealing algorithm, but computationally cheaper. Issues discussed include algorithm speed and robustness, applicability to both computer and mathematical models, and parallel efficiency.
Design of cache memories for multi-threaded dataflow architecture
Authors: Krishna M. Kavi, A. R. Hurson, Phenil Patadia, Elizabeth Abraham, Ponnarasu Shanmugam
Venue: Proceedings of the 22nd annual international symposium on Computer architecture (1995)

Cache memories have proven their effectiveness in the von Neumann architecture when localities of reference govern the execution loci of programs. A pure dataflow program, in contrast, contains no locality of reference since the execution sequence is enforced only by the availability of arguments. Instruction locality may be enhanced if, dataflow programs are reordered. Enhancing the locality of data references in the dataflow architecture is a more challenging problem. In this paper we report our approaches to the design of instruction, data (operand) and I-Structure cache memories using the Explicit Token Store (ETS) model of dataflow systems. We will present the performance results obtained using various benchmark programs.
Stable and efficient reduction of substrate model networks using congruence transforms
Authors: Kevin J. Kerns, Ivan L. Wemple, Andrew T. Yang
Venue: Proceedings of the 1995 IEEE/ACM international conference on Computer-aided design (1995)

Parasitic analog-digital noise coupling has been identified as a key issue facing designers of mixed-signal integrated circuits. In particular, signal cross talk through the common chip substrate has become increasingly problematic. This paper demonstrates a new methodology for developing simulation, synthesis, and verification models to analyze the global electrical behavior of the non-ideal semiconductor substrate. RC substrate network models, which are generated via a triangular discretization method, are accurately approximated for subsequent analysis by an efficient reduction algorithm. This algorithm utilizes the well-conditioned Lanczos process to formulate Pade approximations of the network port admittance. Congruence transformations are employed to ensure stability, and to create reduced networks which are easily realizable with SPICE-compatible RC elements. For validation, the strategy has been successfully applied to several mixed-signal circuit examples.
MMSD'96: workshop on multimedia software development
Authors: Max Mühlhäuser
Venue: ACM SIGSOFT Software Engineering Notes (1996)

Multimedia imposes quite a number of specific issues and requirements on software. While system support for multimedia has been seriously investigated for several years now, the software engineering community has not yet reached a deep understanding of the impacts of multimedia on their field. MMSD'96 brought together a representative spectrum of researchers investigating this issue. Four general observations could be retained from their contributions: 1. distributed multimedia applications exploit both more long-term potential and more persistent research problems than multimedia PC applications; 2. A reference model of multimedia software is not yet in reach; the large number of models proposed, even at MMSD, still lack better rationales, theoretic foundation, and convergence. 3. the MMSD community brings together people with a "document-background" and those with a "software background"; their views and approaches are still far from being harmonized. 4. While the multimedia community struggles for a common understanding among its members, it is in desperate need of a harmonization with approaches to distributed software development. In the remainder of this article, we will review issues to be addressed in the MMSD context, discuss the contributions made at the workshop itself, and draw conclusions for the state of the art.
Components on the Internet (panel)
Authors: Jeffrey Bonar, Nancy Lehrer, Kelly Looney, Randy Schnier, James Russel, Ted Selker, Stewart Nickolas
Venue: ACM SIGPLAN Notices (1996)

The explosive emergence of the Internet forces us to rethink the traditional roles for client, server, and objects. Component technology has emerged as the way objects and frameworks are packaged for flexible object integration. In particular, components allow users who are not programmers to do their own integration. Up until now, components have mainly focused on object integration on end-users desktops and on a client: compound documents, application assembly, etc.Existing component models like OpenDoc and Microsoft's OLE/OCX/COM provide function for compound documents, persistence, scripting, inking, and code management (registration). A series of Internet scenarios are emerging that demand new kinds of components. These scenarios are thin clients (Internet terminals), virtual reality/rich multimedia clients, collaboration, and business data access. Each panelist will explore one of these scenarios for it's requirements on an Internet component model.
Quantum chromodynamics simulation on NWT
Authors: M. Yoshida, A. Nakamura, M. Fukada T. Nakamura S. Hioki
Venue: Proceedings of the 1995 ACM/IEEE conference on Supercomputing (CDROM) (1995)

A portable QCD simulation program running on NWT with 128 PE's shows the performance 0.032 micro sec/link update, which is about 189 times faster than a highly optimized code on CRAY X-MP/48 with four processors. The performance corresponds to 178 GFLOPS sustained speed.
Parallel algorithms for molecular dynamics simulation of irradiation effects in crystals
Authors: Eli Glikman, Ludmila Ioffe, Itzhak Kelson, Shlomit S. Pinter
Venue: Scientific Programming (1995)

We present new parallel algorithms for solving the problem of many body interactions in molecular dynamics (MD). Such algorithms are essential in the simulation of irradiation effects in crystals, where the high energy of the impinging particles dictates computing with large numbers of atoms and for many time cycles. We realized the algorithms using two parallelization methods and compared their performance. Experimental results obtained on a Meiko machine demonstrate that the new algorithms exploit parallelism effectively and can be used to simulate large crystals.
The Euclidian Distance Matrix Completion Problem
Authors: Mihaly Bakonyi, Charles R. Johnson
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

Motivated by the molecular conformation problem, completions of partial Euclidian distance matrices are studied. It is proved that any partial distance matrix with a chordal graph can be completed to a distance matrix. Given any nonchordal graph $G$, it is shown that there is a partial distance matrix $A$ with graph $G$ such that $A$ does not admit any distance matrix completions. Finally, the connection between distance matrix completions and positive semidefinite completions is outlined.
Developing a reflective model of collaborative systems
Authors: Paul Dourish
Venue: ACM Transactions on Computer-Human Interaction (TOCHI) (1995)

Recent years have seen a shift in perception of the nature of HCI and interactive systems. As interface work has increasingly become a focus of attention for the social sciences, we have expanded our appreciation of the importance of issues such as work practice, adaptation, and evolution in interactive systems. The reorientation in our view of interactive systems has been accompanied by a call for a new model of design centered around user needs and participation. This article argues that a new process of design is not enough and that the new view necessitates a similar reorientation in the structure of the systems we build. It outlines some requirements for systems that support a deeper conception of interaction and argues that the traditional system design techniques are not suited to creating such systems. Finally, using examples from ongoing work in the design of an open toolkit for collaborative applications, it illustrates how the principles of computational reflection and metaobject protocols can lead us toward a new model based on open abstraction that holds great promise in addressing these issues.
An Analysis of the Intel 80×86 Security Architecture and Implementations
Authors: Olin Sibert, Phillip A. Porras, Robert Lindell
Venue: IEEE Transactions on Software Engineering (1996)

An in-depth analysis of the 80×86 processor families identifies architectural properties that may have unexpected, and undesirable, results in secure computer systems. In addition, reported implementation errors in some processor versions render them undesirable for secure systems because of potential security and reliability problems. In this paper, we discuss the imbalance in scrutiny for hardware protection mechanisms relative to software, and why this imbalance is increasingly difficult to justify as hardware complexity increases. We illustrate this difficulty with examples of architectural subtleties and reported implementation errors.
Micro-architecture evaluation using performance vectors
Authors: Umesh Krishnaswamy, Isaac D. Scherson
Venue: Proceedings of the 1996 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (1996)

Benchmarking is a widely used approach to measure computer performance. Current use of benchmarks only provides running times to describe the performance of a tested system. Glancing through these execution times provides little or no information about system strengths and weaknesses. A novel benchmarking methodology is proposed to identify key performance parameters; the methodology is based on measuring performance vectors. A performance vector is a vector of ratings that represents delivered performance of primitive operations of a system. Measuring the performance vector of a system in a typical user workload can be a tough problem. We show how the performance vector falls out of an equation consisting of dynamic instruction counts and execution times of benchmarks. We present a non-linear approach for computing the performance vector. The efficacy of the methodology is ascertained by evaluating the micro-architecture of the Sun SuperSPARC superscalar processor using SPEC benchmarks. Results show interesting tradeoffs in the SuperSPARC and speak favorably of our methodology.
A comparison of two methods for advancing time in parallel discrete event simulation
Authors: Anthony P. Galluscio, John T. Douglass, Brian A. Malloy, A. Joe Turner
Venue: Proceedings of the 27th conference on Winter simulation (1995)

We compare the design and implementation of a parallel simulation of a traffic flow network using two different approaches: event-driven and time-driven. Our experiments with the sequential implementation of the two approaches correlates with previous research (Nance, 1971). We design a conservative parallel implementation of the traffic flow problem where we obtain a maximum speedup of 9.27 using 16 Sun workstations running under parallel virtual machine or PVM (Geist et al., 1993). We use wall-clock time as a measure of execution speed. We show that appreciable speedup can be achieved in parallelizing either the event-driven or time-driven approach. We also show that speedup is a misleading metric when used to compare the parallelizability of the two approaches. Parallel performance, as measured by speedup, may be better when the sequential performance is poor. For example, the time-driven implementation achieved better speedup than the event-driven implementation for few cars in the system; however the sequential time-driven implementation required longer to execute than the event-driven implementation for few cars in the system. Similarly for many cars in the system, the event-driven implementation achieved better speedup than the time-driven implementation.
Integrating performance monitoring and communication in parallel computers
Authors: Margaret Martonosi, David Ofelt, Mark Heinrich
Venue: Proceedings of the 1996 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (1996)

A large and increasing gap exists between processor and memory speeds in scalable cache-coherent multiprocessors. To cope with this situation, programmers and compiler writers must increasingly be aware of the memory hierarchy as they implement software. Tools to support memory performance tuning have, however, been hobbled by the fact that it is difficult to observe the caching behavior of a running program. Little hardware support exists specifically for observing caching behavior; furthermore, what support does exist is often difficult to use for making fine-grained observations about program memory behavior.Our work observes that in a multiprocessor, the actions required for memory performance monitoring are similar to those required for enforcing cache coherence. In fact, we argue that on several machines, the coherence/communication system itself can be used as machine support for performance monitoring. We have demonstrated this idea by implementing the FlashPoint memory performance monitoring tool. FlashPoint is implemented as a special performance-monitoring coherence protocol for the Stanford FLASH Multiprocessor. By embedding performance monitoring into a cache-coherence scheme based on a programmable controller, we can gather detailed, per-data-structure, memory statistics with less than a 10% slowdown compared to unmonitored program executions. We present results on the accuracy of the data collected, and on how FlashPoint performance scales with the number of processors.
Implementation trade-offs in using a restricted data flow architecture in a high performance RISC microprocessor
Authors: M. Simone, A. Essen, A. Ike, A. Krishnamoorthy, T. Maruyama, N. Patkar, M. Ramaswami, M. Shebanow, V. Thirumalaiswamy, D. Tovey
Venue: Proceedings of the 22nd annual international symposium on Computer architecture (1995)

The implementation of a superscalar, speculative execution SPARC-V9 microprocessor incorporating Restricted Data Flow principles required many design trade-offs. Consideration was given to both performance and cost. Performance is largely a function of cycle time and instructions executed per cycle while cost is primarily a function of die area. Here we describe our Restricted Data Flow implementation and the means with which we arrived at its configuration. Future semiconductor technology advances will allow these trade-offs to be relaxed and higher performance Restricted Data Flow machines to be built.
Types in objectbases development
Authors: Adoración de Miguel, Mario G. Piattini
Venue: ACM SIGPLAN OOPS Messenger (1995)

During the later years a significant number of data models for objectbases (object models) have been proposed introducing different categories of data types. However, these models usually covers only implementation issues, not considering types throughout all the development phases. In this paper a classification of types in object models is presented and their role along the different development phases is discussed.
Analyzing and redesigning a remote sensing business process for rapid estimates of agriculture in Europe
Authors: Alexandre Zenié, Thomas Schäl
Venue: Proceedings of conference on Organizational computing systems (1995)

This paper1 describes the application of the ActionWorkflow&trade; approach to analyze a European project for monitoring agriculture from high resolution satellite images by using remote sensing techniques. The objective of this study was to improve and maintain coordination between the organizations involved in the remote sensing process which evolved from a pilot phase and became operational. The study of the existing process was supported by the workflow product ActionWorkflow Analyst&trade;. Breakdowns and possible weaknesses identified in the previous process are reported. On the basis of a critical process review, the process is rationalized with an explicit visibility of customers, suppliers, organizational roles, activities and their communicative relation. The reengineered process improves the service to customers in the European Commission (i.e., D.G. VI and Eurostat) and reduces transaction costs due to notable less customer/supplier interactions. Furthermore, there is a clear distinction between recurrent operations (done with more efficiency than in the actual process) and strategic services (with an added value to the management of ad-hoc requests in the previous process). The newly designed business process has been prototyped using the workflow suite by Action Technologies. The appropriateness of the ActionWorkflow&trade; approach and the systems ActionWorkflow Analyst&trade;, Builder&trade; and Manager&trade; for Lotus Notes&trade; are evaluated.
Panel discussion on the role of modeling and simulation in business process reengineering
Venue: Proceedings of the 27th conference on Winter simulation (1995)

Modeling and simulation are important technologies that can be applied to business process reengineering (BPR). Dynamic process models afford the analysis of alternative process scenarios through simulation by providing quantitative process metrics such as cost, cycle time, serviceability and resource utilization. These metrics form the basis for evaluating alternatives and selecting the most promising scenario for implementation. Tradeoffs can be made on the basis of measurements as opposed to intuition, resulting in more informed business decisions. The paper summarizes the ideas to be presented in a panel discussion session on the role of modeling and simulation in business process reengineering. Each panelist represents a different perspective: 1) a theoretical view, 2) a BPR practitioner's view and 3) a software system view. The objective of this session is to highlight key issues in modeling and simulation of business processes from each of these perspectives and to motivate research and tool development in this area.
An Ada-like separate compilation style in C
Authors: Alexy V. Khrabrov
Venue: ACM SIGAda Ada Letters (1995)

The Ada programming language's modularity allows for stepwise refinement in software engineering. Effective separate compilation is crucial in most large systems, including those written in C. An approach to implementing effective modularity in C, modeled after Ada, is explored. The concept of language-independent modularity, and the possibility of implementing it in a given "entry level" language is introduced. An example, a simple sentence parser, is developed in C using this concept. The technique, called A/SC2, may easily be extended to other programming systems and languages. Modeling modularity is a useful design tool.