ppxscal/embedding_network huggingface dataset:
An Inequality for Probability Moments with Applications
Authors: Earl R. Barnes
Venue: SIAM Journal on Discrete Mathematics (1995)

We give an inequality relating the range of a discrete probability distribution to certain determinants formed from moments of the distribution. We show applications of this inequality to problems in geometry, statistics, linear algebra, and combinatorial optimization.
On the Convergence of the Jacobi Method for Arbitrary Orderings
Authors: Walter F. Mascarenhas
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

This paper presents new results concerning the effect of the ordering on the rate of convergence of the Jacobi iteration for computing eigenvalues of symmetric matrices. We start by showing that the diagonal elements converge for any ordering. Next we emphasize that different parts of the matrix converge at different speeds. Taking advantage of this phenomenon, we propose a strategy that leads to a convergence exponent of $ 3^{4/5} \approx 2.41$. Then we show that choosing the rotations to sort the diagonal can improve the convergence by a constant factor and we present experimental results on the performance of this new strategy.
A path-based technique for estimating hardware runtime in HW/SW-cosynthesis
Authors: Jörg Henkel, Rolf Ernst
Venue: Proceedings of the 8th international symposium on System synthesis (1995)

Abstract: One of the key issues in hardware/software-cosynthesis is precise estimation. The usual local estimation techniques are inadequate for globally optimising compilers and synthesis tools. We present a path based estimation technique which allows a computation time/quality tradeoff. The results show acceptable computation times while revealing much more potential parallelism than local list scheduling.
Dynamic reservation multiple access (DRMA): a new multiple access scheme for personal communication systems (PCS)
Authors: Xiaoxin Qiu, Victor O. K. Li
Venue: Wireless Networks (1996)

To improve the spectrum efficiency of integrated voice and data services in Personal Communication System (PCS), several reservation-type multiple access schemes, such as Packet Reservation Multiple Access (PRMA), Dynamic Time Division Multiple Access (D-TDMA), Resource Auction Multiple Access (RAMA), etc., have been proposed. PRMA uses the data packet itself to make a channel reservation, and is inefficient in that each unsuccessful reservation wastes one slot. However, it does not have a fixed reservation overhead and offers shorter access delay. On the other hand, fixed reservation overhead is unavoidable in both RAMA and D-TDMA. Compared to D-TDMA and PRMA, RAMA is superior in the sense that its slot assignment is independent of the traffic load. But its implementation is difficult. With these observations, a new reservation protocol, called Dynamic Reservation Multiple Access (DRMA), is proposed in this paper. With this new protocol, the success probability of channel access is greatly improved at the expense of slightly increased system complexity. It solves the problem of inefficiency in PRMA, but without introducing the fixed reservation overhead as in D-TDMA and RAMA. In addition, it is more suited to the dynamic behavior of the integrated traffic because there is no fixed boundary between voice and data slots (which is mandatory in D-TDMA and RAMA). Our numerical results indicate that its performance is superior to the existing reservation protocols, especially in the integrated traffic scenario. Moreover, the soft capacity feature is exhibited when the traffic load increases.
Some t-Homogeneous Sets of Permutations
Authors: Jürgen Bierbrauer, Stephen Black, Yves Edel
Venue: Designs, Codes and Cryptography (1996)

Perpendicular Arrays are ordered combinatorial structures, which recently have found applications in cryptography. A fundamental construction uses as ingredients combinatorial designs and uniformly t-homogeneous sets of permutations. We study the latter type of objects. These may also be viewed as generalizations of t-homogeneous groups of permutations. Several construction techniques are given. Here we concentrate on the optimal case, where the number of permutations attains the lower bound. We obtain several new optimal such sets of permutations. Each example allows the construction of infinite families of perpendicular arrays.
Improved histograms for selectivity estimation of range predicates
Authors: Viswanath Poosala, Peter J. Haas, Yannis E. Ioannidis, Eugene J. Shekita
Venue: ACM SIGMOD Record (1996)

Many commercial database systems maintain histograms to summarize the contents of relations and permit efficient estimation of query result sizes and access plan costs. Although several types of histograms have been proposed in the past, there has never been a systematic study of all histogram aspects, the available choices for each aspect, and the impact of such choices on histogram effectiveness. In this paper, we provide a taxonomy of histograms that captures all previously proposed histogram types and indicates many new possibilities. We introduce novel choices for several of the taxonomy dimensions, and derive new histogram types by combining choices in effective ways. We also show how sampling techniques can be used to reduce the cost of histogram construction. Finally, we present results from an empirical study of the proposed histogram types used in selectivity estimation of range predicates and identify the histogram types that have the best overall performance.
A Finite Procedure for the Tridiagonalizationof a General Matrix
Authors: A. George, K. Ikramov, A. N. Krivoshapova, W.-P. Tang
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

Interest in the problem of the tridiagonalization of an arbitrary square complex matrix by similarity transformation has been renewed recently through work by Geist, Parlett, Tang and others. To our knowledge, no procedure has so far been presented to compute a tridiagonal matrix similar to a general square complex matrix that requires only a finite number of operations and works for any matrix. In this paper, finite algorithms that are guaranteed to reduce an unreduced Hessenberg matrix or a general matrix to tridiagonal form via similarity transformations are presented. The algorithms are mainly of theoretical interest; that of finding a practical, cost-effective procedure for solving the problem remains an open problem.
Performance effects of architectural complexity in the Intel 432
Authors: Robert P. Colwell, Edward F. Gehringer, E. Douglas Jensen
Venue: ACM Transactions on Computer Systems (TOCS) (1988)

The Intel 432 is noteworthy as an architecture incorporating a large amount of functionality that most other systems perform by software. It has, in effect, &ldquo;migrated&rdquo; this functionality from the software into the microcode and hardware. The benefits of functional migration have recently been a subject of intense controversy, with critics claiming that a complex architecture is inherently less efficient than a simple architecture with good software support. This paper examines the performance impact of the incorporation of several kinds of functionality into the Intel 432. Among these are the addressing structure, the caches, instruction alignment, the buses, and the way that garbage collection is handled. A set of several benchmarks is used to quantify the performance effect of each of these decisions. The results indicate that the 432 could have been speeded up very significantly if a small number of implementation decisions had been made differently, and if incrementally better technology had been used in its construction. Even with these modifications, however, the 432 would still have only one-fourth to one times the speed of its contemporaries. These figures may represent the real cost of the 432's style of object-based programming environment.
Constructing 1-writer multireader multivalued atomic variables from regular variables
Authors: S. Haldar, K. Vidyasankar
Venue: Journal of the ACM (JACM) (1995)

A simple wait-free construction of 1-writer multireader multivalued atomic variable from multireader regular variables is presented in this paper. A key point of the construction is the use of an elegant forwarding technique to overcome the new-old inversion property inherent in regular variables.Another construction, using a different forwarding technique, is also given. This technique is a refinement of one proposed in the literature.Formal correctness proofs for both the constructions are short and easy to follow.
Perspectives on simulation using GPSS
Authors: Thomas J. Schriber
Venue: Proceedings of the 27th conference on Winter simulation (1995)

GPSS (General Purpose Simulation System), a simulation modeling language used to build computer models for discrete-event simulations, is overviewed. The approach taken in GPSS to model a one-line, one-server system is explained, implementation details are provided, and results are discussed. References and suggestions for further study are given.
Computer professionals whose scientific freedom and human rights have been violated&mdash;1984: a report of the ACM committee on scientific freedom and human rights
Authors: Jack Minker
Venue: Communications of the ACM (1985)

This is the third report prepared by the ACM Committee on Scientific Freedom and Human Rights (CSFHR). The first was published in the March 1981 Communications and the second in the December 1982 issue. This report is an update. Since the committee intends to publish future updates, it would appreciate receiving further information about computer scientists whose rights have been violated. Such information should be sent to: Jack Minker, Vice-Chairman, Committee on Scientific Freedom and Human Rights, Department of Computer Science, University of Maryland, College Park, MD 29742.Because those whose scientific freedom or human rights have been violated derive sustenance and support from contacts with their colleagues, the CSFHR has established a program in which ACM chapters &ldquo;adopt&rdquo; individual scientists and correspond with them. Such correspondence should touch on the personal and scientific and not discuss political matters. These letters greatly improve the morale of the recipients and are one of the few ways they can keep current with computer science and technology. This CSFHR program is directed by Helen Takacs (P.O. Drawer CS, Mississippi State, MS 39762).
All-to-all communication on the connection machine CM-200
Authors: Kaph K. Mathur, S. Lennart Johnsson
Venue: Scientific Programming (1995)

Detailed algorithms for all-to-all broadcast and reduction are given for arrays mapped by binary or binary-reflected Gray code encoding to the processing nodes of binary cube networks. Algorithms are also given for the local computation of the array indices for the communicated data, thereby reducing the demand for the communications bandwidth. For the Connection Machine system CM-200, Hamiltonian cycle-based all-to-all communication algorithms yield a performance that is a factor of 2 to 10 higher than the performance offered by algorithms based on trees, butterfly networks, or the Connection Machine router. The peak data rate achieved for all-to-all broadcast on a 2,048-node Connection Machine system CM-200 is 5.4 Gbyte/s. The index order of the data in local memory depends on implementation details of the algorithms, but it is well defined. If a linear ordering is desired, then including the time for local data reordering reduces the effective peak data rate to 2.5 Gbyte/s.
Network routing models applied to aircraft routing problems
Authors: Zhiqiang Chen, Andrew T. Holle, Bernard M. E. Moret, Jared Saia, Ali Boroujerdi
Venue: Proceedings of the 27th conference on Winter simulation (1995)

We study network models applied to two aircraft routing problems, one in which the goal is to route strike aircraft to a target and back so as to to minimize losses and one in which the goal is to route civilian traffic around an airport so as to minimize noise exposure to the population. We propose joint routing as our model: find a required number of time-disjoint routes in a network that minimizes the total cost. We show that joint routing can in turn be modelled as a dynamic network flow problem. We study this problem under several variants and on different types of networks, establishing tight bounds on the running time of exact solutions through applications of both existing and some new methods. We also discuss the modelling of the airspace in which the routing take place and how choices affect the performance of our optimization algorithms. Our model extends to other applications, such as the routing of hazardous materials and of secure communications.
On deductive databases with incomplete information
Authors: Q. Kong, G. Chen
Venue: ACM Transactions on Information Systems (TOIS) (1995)

In order to extend the ability to handle incomplete information in a definite deductive database, a Horn clause-based system representing incomplete information as incomplete constants is proposed. By using the notion of incomplete constants the deductive database system handles incomplete information in the form of sets of possible values, thereby giving more information than null values. The resulting system extends Horn logic to express a restricted form of indefiniteness. Although a deductive database with this kind of incomplete information is, in fact, a subset of an indefinite deductive database system, it represents indefiniteness in terms of value incompleteness, and therefore it can make use of the existing Horn logic computation rules. The inference rules for such a system are presented, its model theory discussed, and a model theory of indefiniteness proposed. The theory is consistent with minimal model theory and extends its expressive power.
Structure exits, not loops
Authors: Mordechai Ben-Ari
Venue: ACM SIGCSE Bulletin (1996)

Until recently, Pascal was the first programming language taught to students. As more schools choose Ada or C++ as a first language, the debate on structured programming has been reopened ([Rob95]). We are no longer restricted to the while-statement: exit/break-statements can be used to exit a loop from the middle, and return from a procedure or function is allowed within a loop statement. Do these constructs violate the principle of structure programming? This article claims that more general loop constructs can be objectively justified, because they simplify the verification of programs. A program that is simple to verify is also easy to explain and understand.
An adjustable user interface providing transparent access to application programs for the physically disabled
Authors: Christian Piwetz, Frank Eiffert, Helmut Heck, Bruno Müller-Clostermann
Venue: Issue 51 (January 1995) (1995)

User interfaces of application programs are usually not designed for the physically disabled [VAN93]. Here we introduce a program for Apple Macintosh computers and PCs using MS-Windows that do assist handicapped users in their interaction with standard application programs. The basic principle is to interact with an interface agent and not with the target application itself, in particular text is entered to the application program via the interface that uses standard operating system mechanisms like the Inter Application Communication (IAC) in the case of the Macintosh. Hence a disabled user may access many different application programs using the same interface. An important feature is the integration of a text prediction component based on the context-sensitive algorithm used in the Reactive Keyboard due to John Darragh and Ian Witten [DWJ90, DAW92]. Currently stable protoype versions for Macintosh and MS-Windows are available.
Principles and practice of unification factoring
Authors: Steven Dawson, C. R. Ramakrishnan, Steven Skiena, Terrance Swift
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1996)

The efficiency of resolution-based logic programming languages, such as Prolog, depends critically on selecting and executing sets of applicable clause heads to resolve against subgoals. Traditional approaches to this problem have focused on using indexing to determine the smallest possible applicable set. Despite their usefulness, these approaches ignore the nondeterminism inherent in many programming languages to the extent that they do not attempt to optimize execution after the applicable set has been determined. Unification factoring seeks to rectify this omission by regarding the indexing and unification phases of clause resolution as a single process. This article formalizes that process through the construction of factoring automata. A polynomial-time algorithm is given for constructing optimal factoring automata that preserve the clause selection strategy of Prolog. More generally, when the clause selection strategy is not fixed, constructing such an optimal automaton is shown to be NP-complete, solving an open trie minimization problem. Unification factoring is implemented through a source code transformation that preserves the full semantics of Prolog. This transformation is specified in the article, and using it, several well-known programs show significant performance improvements across several different systems. A prototype of unification factoring is available by anonymous ftp.
The mathematical validity of software metrics
Authors: B. Henderson-Sellers
Venue: ACM SIGSOFT Software Engineering Notes (1996)

Mathematical modelling, especially in software engineering metrics, requires more emphasis to be placed on the validity of the selected mathematical tools and techniques to be used. There are a plethora of occurrences in the recent literature of the misapplication of quantitative techniques together with errors in the underlying mathematics. Software engineering metrics needs to take more care in its use of mathematics if it is to gain credence in the scientific and engineering communities.
Computational geometry column 26
Authors: Joseph O'Rourke
Venue: ACM SIGACT News (1995)

An advance on Conway's thrackle conjecture is described.
Subtypes vs. where clauses: constraining parametric polymorphism
Authors: Mark Day, Robert Gruber, Barbara Liskov, Andrew C. Myers
Venue: ACM SIGPLAN Notices (1995)

All object-oriented languages provide support for subtype polymorphism, which allows the writing of generic code that works for families of related types. There is also a need, however, to write code that is generic across types that have no real family relationship. To satisfy this need a programming language must provide a mechanism for parametric polymorphism, allowing for types as parameters to routines and types. We show that to support modular programming and separate compilation there must be a mechanism for constraining the actual parameters of the routine or type. We describe a simple and powerful constraint mechanism and compare it with constraint mechanisms in other languages in terms of both ease of use and semantic expressiveness. We also discuss the interaction between subtype and parametric polymorphism: we discuss the subtype relations that can exist between instantiations of parameterized types, and which of those relations are useful and can be implemented efficiently. We illustrate our points using examples in Theta, a new object-oriented language, and we describe the time- and space-efficient implementation of parametric polymorphism used in Theta.
A Modular Systolic Linearization of the Warshall-Floyd Algorithm
Authors: Jean Frédéric Myoupo, Anne Cécile Fabret
Venue: IEEE Transactions on Parallel and Distributed Systems (1996)

In this paper, we use a variant of the geometric method to derive efficient modular linear systolic algorithms for the transitive closure and shortest path problems. Furthermore, we show that partially-pipelined modular linear systolic algorithms with an output operation, for matrix multiplication, can be as fast as the fully-pipelined existing ones and, moreover, they need less cells.
Regarding test functions for multi-dimensional integration
Authors: W. J. Whiten, L. Kocis
Venue: ACM SIGNUM Newsletter (1995)

Monte Carlo and quasi Monte Carlo (ie using low discrepancy sequences) methods (Bratley amp; Fox 1988, Joe amp; Sloan 1993, Krommer amp; Ueberhuber 1994, Lyness 1989, Niederreiter 1978, Sloan amp; Kachoyan 1987) are used to approximate an integral by the average value of function samples:[EQUATION 1]where v is the volume of integration (taken here to be the unit multi-dimensional cube) and x is a vector with an element for each of the dimensions of the multidimensional space. In the case of Monte Carlo the points xp are chosen at random, while in quasi Monte Carlo the points are chosen to cover the integration volume as uniformly as possible. For numerical integration over a large number of dimensions these two techniques are often the only methods available.
Device-directed rendering
Authors: Andrew S. Glassner, Kenneth P. Fishkin, David H. Marimont, Maureen C. Stone
Venue: ACM Transactions on Graphics (TOG) (1995)

Rendering systems can produce images that include the entire range of visible colors. Imaging hardware, however, can reproduce only a subset of these colors: the device gamut. An image can only be correctly displayed if all of its colors lie inside of the gamut of the target device. Current solutions to this problem are either to correct the scene colors by hand, or to apply gamut mapping techniques to the final image. We propose a methodology called device-directed rendering that performs scene color adjustments automatically. Device-directed rendering applies classic minimization techniques to a symbolic representation of the image that describes the relationship of the scene lights and surfaces to the pixel colors. This representation can then be evaluated to produce an image that is guaranteed to be in gamut. Although our primary application has been correcting out-of-gamut colors, this methodology can be generally applied to the problem of adjusting a scene description to accommodate constraints on the output image pixel values.
An architectural approach for integrated network and systems management
Authors: Raouf Boutaba, Simon Znaty
Venue: ACM SIGCOMM Computer Communication Review (1995)

Today's enterprises are accepting networked systems as a fundamental part of their information technology strategy. The constant growth in quantity and quality of networked systems and the thereby arising problems concerning complexity, heterogeneity and diversity of components in a multi-vendor environment require a sophisticated management of resources. Increasingly the automation of such management is being demanded.In this paper we introduce an architecture for the integrated management of all resources in a networked system, i.e. application, system and network resources. The architecture uses domains as flexible and pragmatic means of grouping resources and of specifying management responsibility and authority boundaries. It maintains a clear distinction between management objectives and the resources being managed in order to provide an integrated view of the various tasks of management as well as an integrated and uniform view of the distributed and heterogeneous managed environment. The uniform management model on which the architecture is based is expressive enough to capture the full richness of management structures and policies both within enterprises and between them. It allows for recursive and generic structuring, we consider as the basis for management activity automation.As an example, we apply our architectural concepts to structure the management of a high speed multi-network (ATM, DQDB, FDDI). Emphasis lies on an automated Quality of Service management in the FDDI management domain.