ppxscal/embedding_network huggingface dataset:
Spectral Radii of Fixed Frobenius Norm Perturbations of Nonnegative Matrices
Authors: Lixing Han, Michael Neumann, Michael Tsatsomeros
Venue: SIAM Journal on Matrix Analysis and Applications (1999)

Let A be an n X n nonnegative matrix. In this paper we consider the problems of maximizing the spectral radii of (i) A + ,X. and (ii) A + D, where X is a real n X n matrix whose Frobenius norm is restricted to be 1 and where D is as X but is further constrained to be a diagonal matrix. For both problems the maximums occur at nonnegative X and D, and we use tools of nonnegative matrices, most notably due to Levinger and Fiedler, as well as the Kuhn--Tucker criterion for constrained optimization, to find upper and lower bounds on the maximums, and, when A is additionally assumed to be irreducible, to characterize cases of equalities in these bounds. In the case of the first problem, when A is irreducible, we characterize a matrix which gives the global maximum. A matrix which yields a global maximum to the second problem is more complicated to characterize as, depending on A, the problem admits local maximums within the nonnegative diagonal matrices of Frobenius norm 1.
Specification formalisms for component-based concurrent systems
Authors: Rance Cleaveland
Venue: ACM SIGSOFT Software Engineering Notes (2000)

This project builds on my ongoing research into design formalisms for, and the automatic verification of, concurrent systems. The difficulties such systems pose for system engineers are well-known and result in large part from the the complexities of process interaction and the possibilities for nondeterminism. My work is motivated by a belief that mathematically rigorous specification and verification techniques will ultimately lead to better and easier-to-build concurrent systems.My specific research interests lie in the development of fully automatic analysis methods and process-algebraic design formalisms for modeling system behavior. I have worked on algorithms for checking properties of, and refinement relations between, system descriptions [CH93, CS93]; the implementation and release of a verification tool, the CWB- NC [CS96] (see http://www.cs.sunysb.edu/~rance to obtain the distribution); case studies [BCL99, ECB97]; and the formalization of system features, such as real time, probability, and priority, in process algebra [BCL99, CDSYar].The aims of this project include the development of expressive and usable formalisms for specifying and reasoning about properties of open, component-based concurrent systems. More specifically, my colleagues and I have been investigating new approaches for describing component requirements and automated techniques for determining when finite-state components meet their requirements. The key topics under study include the following.A temporal logic for open systems. We are working on a notation for conveniently expressing properties constraining the behavior of open systems.Implicit specifications. Implicit specifications use system contexts, or "test harness," to define requirements for open systems. We are studying expressiveness issues and model-checking algorithms for such specifications.Automatic model-checker generation. We have been developing a model-checker generator that, given a temporal logic and "proof rules" for the logic, automatically produces an efficient model checker.
Enhanced reserved polling multiaccess technique for multimedia personal communication systems
Authors: Benny Bing, Regu Subramanian
Venue: Wireless Networks (1999)

This article describes a multiaccess technique which allows the transport of multimedia information across global personal communication systems (PCS). Impressive growth in the application of wireless technologies to telecommunications has sparked active research on a new generation of mobile radio networks projected to handle heterogeneous traffic types. One of the key requirements of these advanced systems is the multiaccess protocol which must guarantee quality of service and provide efficient access to multirate broadband applications that combine voice, video and data communications. In addition, the protocol is required to operate with the demanding constraints imposed by moving users, dynamic traffic load variations and highly sensitive wireless links. To this end, a multiaccess scheme called &ldquo;enhanced reserved polling&rdquo; is proposed. The scheme is designed to execute many PCS-related functions including radio resource assignment, connection control and mobility management. It accommodates a diverse mixture of delay classes/message priorities and can also enhance the bandwidth sharing among different cells in the network.
Why don&rsquo;t they practice what we preach&quest;
Authors: Watts S. Humphrey
Venue: Annals of Software Engineering (1999)

One of the most intractable problems in software is getting engineers to consistently use effective methods. The Software Engineering Institute (SEI) has worked on this problem for a number of years and has developed effective methods for addressing it. This paper describes these methods and shows what they have accomplished with several hundred students and working engineers. After first describing the problem of changing engineers&rsquo; practices, the paper discusses the logic engineers typically follow in deciding what methods to use. Next is a description of the Personal Software Process (PSP) and the Team Software Process (TSP). Finally, the implications of SEI&rsquo;s experiences with the PSP and TSP are described, with particular emphasis on software engineering and computer science education.
Cancellation errors in multivariate resultant computation with floating-point numbers
Authors: Tateaki Sasaki, Tomoyuki Sato
Venue: ACM SIGSAM Bulletin (1998)

We test five methods of computing resultant of multivariate polynomials with floating-point number coefficients, mostly from the viewpoint of numerical errors. The methods tested are a) Brown-Traub's subresultant PRS algorithm, b) Collins' algorithm based on polynomial interpolation, c) minor expansion method of Bezout's determinant, d) Gaussian elimination method (Bareiss' algorithm) of Bezout's determinant, and e) efficient Gaussian elimination method (Sasaki-Murao's algorithm) of Bezout's determinant. We find that method a) causes so large cancellation errors that it is almost useless practically. The errors caused by methods b) and d) are not so large as those by a) but still large. The methods c) and e) are quite safe against the cancellation error and they are efficient, too. Mechanisms of occurrence of large cancellation errors in methods a), b) and d) are clarified. By these, we show that approximate algebraic computation often causes large cancellation errors hence the error analysis and development of error-safe algorithms are very important.
Estimating Hospital Inefficiency: Does Case Mix Matter?
Authors: Michael D. Rosko, Jon A. Chilingerian
Venue: Journal of Medical Systems (1999)

A two-stage approach is used in a stochastic frontier analysis of the factors affecting hospital efficiency. In the first stage, a translog cost-function is used to estimate inefficiency scores. In the second stage, inefficiency scores are regressed against independent variables to test hypotheses that come from X-inefficiency Theory. The study was based on 1989 data for 195 Pennsylvania acute care hospitals. This data base was chosen because of the availability of patient-level severity of illness data, a measure of output that is not available from most data sources. The stochastic frontier analysis models estimated mean inefficiency scores that ranged from 0.075 to 0.180. The addition of the DRG case mix index (CMI) reduced estimated inefficiency by more than 50%. The incremental effect of a severity of illness variable to an equation with CMI was very small. The second-stage results suggest inefficiency and are inversely associated with regulatory pressures and industry concentration.
A low-complexity issue logic
Authors: Ramon Canal, Antonio González
Venue: Proceedings of the 14th international conference on Supercomputing (2000)

One of the main concerns in today's processor design is the issue logic. Instruction-level parallelism is usually favored by an out-of-order issue mechanism where instructions can issue independently of the program order. The out-of-order scheme yields the best performance but at the same time introduces important hardware costs such as an associative look-up, which might be prohibitive for wide issue processors with large instruction windows. This associative search may slow-down the clock-rate and it has an important impact on power consumption. In this work, two new issue schemes that reduce the hardware complexity of the issue logic with minimal impact on the average number of instructions executed per cycle are presented.
Chronos: a Performance Characterization Tool Inside the EDPEPPS Toolset
Authors: J. Bourgeois, F. Spies, M. J. Zemerly, T. Delaitre
Venue: The Journal of Supercomputing (2000)

The EDPEPPS toolset is the fruit of a 10 man-year-research development and integrates many modules in order to predict and classify the execution times of C/PVM programs mapped on a cluster of heterogeneous workstations. In this project, a performance characterization tool called Chronos has been developed to model the processor and C instructions. Chronos can be used to characterize a wide range of machines as it is developed round a specialized benchmark. Chronos uses a parameter-based model and characterizes the machine and the program studied. Then, the execution predictor evaluates the time spent in each program block, according to a generic model of cache memory which simulates most of the CPU internal cache memory architecture. Chronos does not need any user's intervention as all the operations are automatic. The performance accuracy of Chronos is highlighted by a real processor-consuming sequential example.This tool can be used by designers to predict the average execution time of their applications quickly. Average percentage errors obtained from this tool are below 10%.
Fully Coupled Forward-Backward Stochastic Differential Equations and Applications to Optimal Control
Authors: Shige Peng, Zhen Wu
Venue: SIAM Journal on Control and Optimization (1999)

Existence and uniqueness results of fully coupled forward-backward stochastic differential equations with an arbitrarily large time duration are obtained. Some stochastic Hamilton systems arising in stochastic optimal control systems and mathematical finance can be treated within our framework.
Patterns of entry and correction in large vocabulary continuous speech recognition systems
Authors: Clare-Marie Karat
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

A study was conducted to evaluate user performance and satisfaction in completion of a set of text creation tasks using three commercially available continuous speech recognition systems. The study also compared user performance on similar tasks using keyboard input. One part of the study (Initial Use) involved 24 users who enrolled, received training and carried out practice tasks, and then completed a set of transcription and composition tasks in a single session. In a parallel effort (Extended Use), four researchers used speech recognition to carry out real work tasks over 10 sessions with each of the three speech recognition software products. This paper presents results from the Initial Use phase of the study along with some preliminary results from the Extended Use phase. We present details of the kinds of usability and system design problems likely in current systems and several common patterns of error correction that we found.
A multi-disciplinary framework for the management of interorganizational systems
Authors: Ram L. Kumar, Connie W. Crook
Venue: ACM SIGMIS Database (1999)

Interorganizational information systems (IOS) are information technology (IT)-based systems that link multiple organizations. Management of these systems could be significantly more complex than managing IT within individual organizations. We explore the complexities of managing IOS using case studies and propose a multidisciplinary framework that includes collaboration, organization, and technology issues for the design and management of such organizations. Multiple case studies are presented to illustrate the proposed framework. Managerial and research implications are also discussed.
Factors affecting professional competence of information technology professionals
Authors: J. Ellis Blanton, Thomas Schambach, Kenneth J. Trimmer
Venue: ACM SIGCPR Computer Personnel (1998)

Design and development of effective information technology (IT) based systems depends upon a staff of competent information technology professionals (ITPs). Due to the rapid pace of technological innovation, diverging application of IT, and changing role responsibilities of ITPs, it is becoming increasingly difficult for ITPs to maintain up-to-date professional competency.Although not extensively examined in IT research, professional obsolescence threats have been acknowledged and evaluated in referent research. Psychologists studying the engineering discipline have suggested individual characteristics, nature of work, and organizational climate as being important determinants of obsolescence.The purpose of this study was to evaluate the relationships between individual personality differences and manageable work context factors and the degree of professional competency, or conversely obsolescence of ITPs. Structural equation modeling was employed in evaluating the direct-effects model of professional competency. The study used questionnaires to obtain 161 usable self-report responses from systems analysts. The results suggest that individual personality differences and factors of the work environment do effect professional competency levels. Overall, the research model accounted for 44% of the variance in ITP competency.
Hypertext information retrieval for the Web
Authors: Eric W. Brown, Alan F. Smeaton
Venue: ACM SIGIR Forum (1998)

The notion of searching a hypertext corpus has been around for some time, and is an especially important topic given the growth of the World Wide Web and the general dissatisfaction users have with the tools currently available for finding information on the Web. In response to this, a workshop was held as part of SIGIR'98 on Hypertext Information Retrieval for the Web and this document presents a brief summary of the papers presented at that workshop, along with a set of themes identified as a result of group discussion and some conclusions on where to go next.
Prioritizing remote procedure calls in Ada distributed systems
Authors: J. J. Gutiérrez García, M. González Harbour
Venue: Proceedings of the ninth international workshop on Real-time Ada (1999)

In this paper we discuss the assignment of priorities to the execution of remote procedure calls in distributed real-time systems that are programmed using the Distributed Systems Annex (DSA) of Ada 95. We first discuss the current priority model used in the Glade implementation of the DSA. We then present some theoretical results that show that a more flexible priority assignment methodology can provide much better schedulable utilization levels. Based upon these results we propose an implementation that would allow using this priority assignment methodology in Glade. Finally, we propose new features for a future DSA that would allow prioritizing remote procedure calls in a flexible manner.
Protecting UNIX Systems: Security Management with CA-UNICENTER
Authors: Katherine Jones
Venue: International Journal of Network Management (1996)

Created around a series of concepts, CA-UNICENTER addresses system entry validation, password controls, asset security, audit concerns, protection by default, protection by definition, and policy-based security.
State Dependent Expected Utility for Savage's State Space
Authors: Peter P. Wakker, Horst Zank
Venue: Mathematics of Operations Research (1999)

This paper generalizes the Debreu/Gorman characterization of additively decomposable functionals and separable preferences to infinite dimensions. The first nove lty concerns the very definition of additively decomposable functionals for infinite dimensions. For decision under uncertainty, our result provides a state-dependent extension of Savage's expected utility. A characterization in terms of preference condi tions identifies the empirical content of the model; it amounts to Savage's axiom system with P4 (likelihood ordering) dropped. Our approach does not require that a (probability) measure on the state space be given a priori, or can be derived from extraneous conditions outside the realm of decision theory. Bayesian updating of new information is still possible, even though no prior probabilities are given. The finding suggests that the sure-thing principle, rather than prior probability, is at the heart of Bayesian updating.
Computer-generated pen-and-ink illustration of trees
Authors: Oliver Deussen, Thomas Strothotte
Venue: Proceedings of the 27th annual conference on Computer graphics and interactive techniques (2000)

We present a method for automatically rendering pen-and-ink illustrations of trees. A given 3-d tree model is illustrated by the tree skeleton and a visual representation of the foliage using abstract drawing primitives. Depth discontinuities are used to determine what parts of the primitives are to be drawn; a hybrid pixel-based and analytical algorithm allows us to deal efficiently with the complex geometric data. Using the proposed method we are able to generate illustrations with different drawing styles and levels of abstraction. The illustrations generated are spatial coherent, enabling us to create animations of sketched environments. Applications of our results are found in architecture, animation and landscaping.
Algebraic Foundations and Broadcasting Algorithms for Wormhole-Routed All-Port Tori
Authors: San-Yuan Wang, Yu-Chee Tseng
Venue: IEEE Transactions on Computers (2000)

The one-to-all broadcast is the most primary collective communication pattern in a multicomputer network. We consider this problem in a wormhole-routed torus which uses the all-port and dimension-ordered routing model. We derive our routing algorithms based on the concept of ¿span of vector spaces¿ in linear algebra. For instance, in a 3D torus, the nodes receiving the broadcast message will be ¿spanned¿ from the source node to a line of nodes, to a plane of nodes, and then to a cube of nodes. Our results require at most $2(k-1)$ steps more than the optimal number of steps for any square $k$-D torus. Existing results, as compared to ours, can only be applied to tori of very restricted dimensions or sizes and either rely on an undesirable non-dimension-ordered routing or require more numbers of steps.
A Fast Neural Learning Vision System for Crowd Estimation at Underground Stations Platform
Authors: Siu-Yeung Cho, Tommy W. S. Chow
Venue: Neural Processing Letters (1999)

A neural learning-based crowd estimation system for surveillance in complex scenes at the platform of underground stations is presented. Estimation is carried out by extracting a set of significant features from the sequences of images. Feature indices are modeled by the neural networks to estimate the crowd density. The learning phase is based on our proposed hybrid algorithms which are capable of providing the global search characteristic and fast convergence speed. Promising experimental results were obtained in terms of estimation accuracy and real-time response capability to alert the operators automatically.
On Families of Pointwise Optimal Finite Volume ENO Approximations
Authors: Thomas Sonar
Venue: SIAM Journal on Numerical Analysis (1998)

The present work is devoted to the construction of radial functions which can serve as recovery functions in essentially nonoscillatory (ENO) approximations of hyperbolic conservation laws on unstructured grids. Conditionally positive $\lambda$-definite radial functions are shown to be pointwise optimal and therefore very well suited for use in finite volume schemes. In the present paper we develop the theory of pointwise optimality and give examples.
Advanced drawing tools aid network planning
Authors: Nathan J. Muller
Venue: International Journal of Network Management (1997)

Network administrators can facilitate managing large, complex networks by using diagramming solutions. This article describes and discuses a variety of tools that are available to aid the design process. &copy; 1997 John Wiley & Sons, Ltd.
The Use of Simulation in Planning the Transportation of Patients to Hospitals Following a Disaster
Authors: P. Maria Joseph Christie, Reuven R. Levary
Venue: Journal of Medical Systems (1998)

The characteristics of disaster management are outlined. Planning for the efficient management of a disaster is described. The level of preparedness for disasters can be increased using simulation models in conjunction with drills. With the simulation model, &ldquo;what-if&rdquo; analyses are performed to predict the consequences of conceivable scenarios. Emergency medical service personnel will find such computer simulation models a useful supplement to their standard training.
StackThreads/MP: integrating futures into calling standards
Authors: Kenjiro Taura, Kunio Tabata, Akinori Yonezawa
Venue: ACM SIGPLAN Notices (1999)

An implementation scheme of fine-grain multithreading that needs no changes to current calling standards for sequential languages and modest extensions to sequential compilers is described. Like previous similar systems, it performs an asynchronous call as if it were an ordinary procedure call, and detaches the callee from the caller when the callee suspends or either of them migrates to another processor. Unlike previous similar systems, it detaches and connects arbitrary frames generated by off-the-shelf sequential compilers obeying calling standards. As a consequence, it requires neither a frontend preprocessor nor a native code generator that has a builtin notion of parallelism. The system practically works with unmodified GNU C compiler (GCC). Desirable extensions to sequential compilers for guaranteeing portability and correctness of the scheme are clarified and claimed modest. Experiments indicate that sequential performance is not sacrificed for practical applications and both sequential and parallel performance are comparable to Cilk[8], whose current implementation requires a fairly sophisticated preprocessor to C. These results show that efficient asynchronous calls (a.k.a. future calls) can be integrated into current calling standard with a very small impact both on sequential performance and compiler engineering.
Some reflections on software engineering research
Authors: Alfonso Fuggetta
Venue: ACM SIGSOFT Software Engineering Notes (1999)

The May and July issues of ACM Software Engineering Notes include three stimulating and thought-provoking papers, two by David Lorge Parnas and one by David Notkin. The papers discuss the nature of software engineering research and identify problems and issues that the community is facing. After reading them, I felt compelled to assess the research I have been doing during the past years. These notes are just an attempt to organize and structure in a written form the impressions and concerns that I have derived from this reflection. I hope they can be useful to continue and deepen the discussion on the subject.To anticipate some possible negative reactions to these notes, I admit up front that my comments might appear biased, harsh, and perhaps too pessimistic. Please consider them first and foremost as a sincere critique of myself. I do believe that the only way to solve problems is to address them without any fear or ambiguity. Ignoring or avoiding problems would just mean that we do not have the ability or the courage to solve them.