ppxscal/embedding_network huggingface dataset:
Adaptive dynamic process scheduling on distributed memory parallel computers
Authors: Wei Shu
Venue: Scientific Programming (1994)

One of the challenges in programming distributed memory parallel machines is deciding how to allocate work to processors. This problem is particularly important for computations with unpredictable dynamic behaviors or irregular structures. We present a scheme for dynamic scheduling of medium-grained processes that is useful in this context. The adaptive contracting within neighborhood (ACWN) is a dynamic, distributed, load-dependent, and scalable scheme. It deals with dynamic and unpredictable creation of processes and adapts to different systems. The scheme is described and contrasted with two other schemes that have been proposed in this context, namely the randomized allocation and the gradient model. The performance of the three schemes on an Intel iPSC/2 hypercube is presented and analyzed. The experimental results show that even though the ACWN algorithm incurs somewhat larger overhead than the randomized allocation, it achieves better performance in most cases due to its adaptiveness. Its feature of quickly spreading the work helps it outperform the gradient model in performance and scalability.
Invariants, Frames and Postconditions: A Comparison of the VDM and B Notations
Authors: Juan Bicarregui, Brian Ritchie
Venue: IEEE Transactions on Software Engineering (1995)

VDM and B are two ¿model-oriented¿ formal methods. Each gives a notation for the specification of systems as state machines in terms of a set of states with operations defined as relations on that set. Each has a notion of refinement of data and operations based on the principles of reduction of nondeterminism and increase in definedness. This paper makes a comparison of the two notations through an example of a communications protocol previously formalized in [1]. Two abstractions and two reifications of the original specification are given. Particular attention is paid to three areas where the notations differ: the use of postconditions that assume the invariant as opposed to postconditions that enforce it; the explicit ¿framing¿ of operations as opposed to the ¿minimal frame¿ approach; and the use of relational postconditions as opposed to generalized substitutions.
Information superhighway 2015
Authors: Peter J. Denning
Venue: Communications of the ACM (1995)

hospitable as the traditional ones.
Some p-Ranks Related to Orthogonal Spaces
Authors: Aart Blokhuis, G. Eric Moorhouse
Venue: Journal of Algebraic Combinatorics: An International Journal (1995)

We determine the p-rank of the incidence matrix of hyperplanes of PG(n, pe) and points of a nondegenerate quadric. This yields new bounds for ovoids and the size of caps in finite orthogonal spaces. In particular, we show the nonexistence of ovoids in O^+_{10}(2^e), O_{10}^+(3^e), O_9(5^e), O^+_{12}(5^e) and O^+_{12}(7^e). We also give slightly weaker bounds for more general finite classical polar spaces. Another application is the determination of certain explicit bases for the code of PG(2, p) using secants, or tangents and passants, of a nondegenerate conic.
Nearly optimal algorithms and bounds for multilayer channel routing
Authors: Bonnie Berger, Martin Brady, Donna Brown, Tom Leighton
Venue: Journal of the ACM (JACM) (1995)

This paper presents algorithms for routing channels with L&ge;2 layers. For the unit vertical overlap model, we describe a two-layer channel routing algorithm that uses at most d+Od tracks to route two-terminal net problems and 2d+od tracks to route multiterminal nets. We also show that d+Wlog d tracks are required to route two-terminal net problems in the worst case even if arbitrary vertical overlap is allowed. We generalize the algorithm to unrestricted multilayer routing and use only d/L-1+O d/L+1 tracks for two-terminal net problems (within within Od/L+ 1tracks of optimaland d/L-2+O d/L+1 tracks for multiterminal net problems within a factor ofL-1 /L-2times optimal . We demonstrate the generality of our routing strategy by showing that it can be used to duplicate some of the best previous upper bounds for other models (two-layer Manhattan routing and two and three-layer knock-knee routing of two-terminal, two-sided nets), and gives a new upper bound for rotuing with 45-degree diagonal wires.
DataMine&mdash;interactive rule discovery system
Authors: T. Imielinski, A. Virmani
Venue: Proceedings of the 1995 ACM SIGMOD international conference on Management of data (1995)

DataMine is a statistical database mining system with strong emphasis on interactiveness and nice graphical representation of information produced. It also supports an offline mode of discovery, and provides an extensive API which allows users to write "mining applications" just as easily as routine database applications, The central idea is to perform discovery with a "human in the loop" guiding the system using his initial hypothesis and the feedback from the system. Users can pose a rule-query against a rulebase and the system can generate all rules matching their query. The rulebase could either be pregenerated (using offline mode) or could be realized in real-time as the discovery progresses.Rules generated by the system are of the form:Body - gt; Consequentwhere Body is a conjunction of the elementary predicates of the form (A=a), where A is an attribute and a is a value from the attribute domain of A. Consequent is a single elementary predicate. Each rule can have several parameters like support, confidence, atypicality, color etc. (the definitions have been left out) which can also be used by the user in framing the rule query.For continuous attributes, the system also allows the user some control in deciding how they are discretized. It also allows for the creation of extra attributes at run time which can then be used in queries like the rest.
Multilevel Hierarchical Decision Making in Stochastic Marketing-Production Systems
Authors: S. P. Sethi, Q. Zhang
Venue: SIAM Journal on Control and Optimization (1995)

This paper presents an asymptotic analysis of hierarchical marketing-production systems with stochastic demand and stochastic production capacity modelled as finite state Markov processes. The decision variables used are advertising and production rates which influence capacity, demand, and inventory levels. The objective of this paper is to maximize the expected total discounted profit over an infinite horizon. The authors are interested in situations in which the rate of change in capacity states is an order of magnitude different from the rate of change in demand states. These give rise to upper-level problems in which the stochastic capacity is replaced by the average capacity and/or the random demand is replaced by the average demand. Controls for the corresponding lower-level problems in different cases can be constructed from nearly optimal controls of the upper-level problems in a way that guarantees their asymptotic optimality.
Tile size selection using cache organization and data layout
Authors: Stephanie Coleman, Kathryn S. McKinley
Venue: ACM SIGPLAN Notices (1995)

When dense matrix computations are too large to fit in cache, previous research proposes tiling to reduce or eliminate capacity misses. This paper presents a new algorithm for choosing problem-size dependent tile sizes based on the cache size and cache line size for a direct-mapped cache. The algorithm eliminates both capacity and self-interference misses and reduces cross-interference misses. We measured simulated miss rates and execution times for our algorithm and two others on a variety of problem sizes and cache organizations. At higher set associativity, our algorithm does not always achieve the best performance. However on direct-mapped caches, our algorithm improves simulated miss rates and measured execution times when compared with previous work.
Amortized Communication Complexity
Authors: Tomas Feder, Moni Naor, Eyal Kushilevitz, Noam Nisan
Venue: SIAM Journal on Computing (1995)

In this work we study the direct-sum problem with respect to communication complexity: Consider a relation $f$ defined over $\{0,1\}^{n} \times \{0,1\}^{n}$. Can the communication complexity of simultaneously computing $f$ on $\cal l$ instances $(x_1,y_1),\ldots,(x_{\cal l},y_{\cal l})$ be smaller than the communication complexity of computing $f$ on the $\cal l$ instances, separately? Let the amortized communication complexity of $f$ be the communication complexity of simultaneously computing $f$ on $\cal l$ instances, divided by $\cal l$. We study the properties of the amortized communication complexity. We show that the amortized communication complexity of a relation can be smaller than its communication complexity. More precisely, we present a partial function whose (deterministic) communication complexity is $\Theta(\log n)$ and its amortized (deterministic) communication complexity is $O(1)$. Similarly, for randomized protocols, we present a function whose randomized communication complexity is $\Theta(\log n)$ and its amortized randomized communication complexity is $O(1)$. We also give a general lower bound on the amortized communication complexity of any function $f$ in terms of its communication complexity $C(f)$: for every function $f$ the amortized communication complexity of $f$ is $\Omega \left (\sqrt{C(f)} - \log n \right)$.
Pricing in computer networks: reshaping the research agenda
Authors: S. Shenker, D. Clark, D. Estrin, S. Herzog
Venue: ACM SIGCOMM Computer Communication Review (1996)

As the Internet makes the transition from research testbed to commercial enterprise, the topic of pricing in computer networks has suddenly attracted great attention. Much of the discussion in the network design community and the popular press centers on the usage-based vs. flat pricing debate. The more academic literature has largely focused on devising optimal pricing policies; achieving optimal welfare requires charging marginal congestion costs for usage. In this paper we critique this optimality paradigm on three grounds: (1) marginal cost prices may not produce sufficient revenue to fully recover costs and so are perhaps of limited relevance, (2) congestion costs are inherently inaccessible to the network and so cannot reliably form the basis for pricing, and (3) there are other, more structural, goals besides optimality, and some of these goals are incompatible with the global uniformity required for optimal pricing schemes. For these reasons, we contend that the research agenda on pricing in computer network should shift away from the optimality paradigm and focus more on structural and architectural issues. Such issues include allowing local control of pricing policies, fostering interconnection, handling multicast appropriately, and allowing receivers to pay for transmission. To illustrate our point, we describe how these goals might be accomplished in the context of a different pricing paradigm: edge pricing. In addition, we argue that in the context of this edge pricing paradigm, usage-based pricing and flat pricing are not radically different but instead both reside along the single continuum of usage-constraining pricing policies.
Analyzing multivariate output
Authors: John M. Charnes
Venue: Proceedings of the 27th conference on Winter simulation (1995)

This paper gives an overview of multivariate statistical techniques that can be useful for analyzing discrete-event simulation output, and describes some of the latest directions in research on multivariate output analysis. A general discussion is given of constructing joint confidence regions on the mean vector of multivariate output from independent replications of terminating models. The multivariate batch means method of simultaneous estimation of means from one long run of steady-state simulation models is described. References are also given for autoregressive, spectral analysis and regenerative methods of inference, as well as variance-reduction and sequential techniques.
Development and evaluation of hypermedia for museum education: validation of metrics
Authors: Shoji Yamada, Jung-Kook Hong, Shigeharu Sugita
Venue: ACM Transactions on Computer-Human Interaction (TOCHI) (1995)

To define a hypermedia system's ease of use from the user's point of view, we propose three evaluation metrics: an interface shallowness metric, a downward compactness metric, and a downward navigability metric. These express both the cognitive load on users and the structural complexity of the hypermedia contents. We conducted a field study at the National Museum of Ethnology (NME) in Osaka, Japan, to evaluate our hypermedia system and to assess the suitability of our hypermedia metrics from the viewpoint of visiting members of the public. After developing a spreadsheet-type authoring system named HyperEX, we built prototype systems for use by members of the public visiting a special exhibition held at the museum. Questionnaires, interviews, automatic recording of users' navigation operations, and statistical analysis of 449 tested users yielded the following results. First, the suitability of the metrics was found to be satisfactory, indicating that they are useful for developing hypermedia systems. Second, there is a strong relationship between a system's enjoyability and its usability. Transparency and the friendliness of the user interface are the key issues in enjoyability. Finally, the quality of the video strongly affects the overall system evaluation. Video quality is determined by optimum selection of scenes, the length of the video, and appropriate audio-visual expression of the content. This video quality may become the most important issue in developing hypermedia for museum education.
Launching the usability approach: experience at Helsinki University of Technology
Authors: Marja-Riitta Koivunen, Marko Nieminen, Sirpa Riihiaho
Venue: ACM SIGCHI Bulletin (1995)

This article describes how the usability approach was introduced into Finnish companies and to computer science students by combining teaching and real cases from companies. Two courses were developed where usability study projects were part of the usability education. The courses not only taught the evaluation methods but also radically changed the students' attitudes towards usability.
Multiscalar processors
Authors: Gurindar S. Sohi, Scott E. Breach, T. N. Vijaykumar
Venue: Proceedings of the 22nd annual international symposium on Computer architecture (1995)

Multiscalar processors use a new, aggressive implementation paradigm for extracting large quantities of instruction level parallelism from ordinary high level language programs. A single program is divided into a collection of tasks by a combination of software and hardware. The tasks are distributed to a number of parallel processing units which reside within a processor complex. Each of these units fetches and executes instructions belonging to its assigned task. The appearance of a single logical register file is maintained with a copy in each parallel processing unit. Register results are dynamically routed among the many parallel processing units with the help of compiler-generated masks. Memory accesses may occur speculatively without knowledge of preceding loads or stores. Addresses are disambiguated dynamically, many in parallel, and processing waits only for true data dependences.This paper presents the philosophy of the multiscalar paradigm, the structure of multiscalar programs, and the hardware architecture of a multiscalar processor. The paper also discusses performance issues in the multiscalar model, and compares the multiscalar paradigm with other paradigms. Experimental results evaluating the performance of a sample of multiscalar organizations are also presented.
Using iterative enhancement in undergraduate software engineering courses
Authors: David H. Hutchens, Elizabeth E. Katz
Venue: Proceedings of the twenty-seventh SIGCSE technical symposium on Computer science education (1996)

Many software development courses include both instruction in formal and informal techniques and application of those techniques on a team project. In teaching such a course, a dilemma arises in trying to present material in sufficient detail before students must apply the material in their projects. The students are not comfortable with a technique before they must use it. If the project is moved later in the course, the students do not have enough time to tackle a problem that is big enough to require many of the software development techniques. There must be a better approach to teaching the course without separating the material into two courses or dividing the course over two terms.This paper describes an iterative approach. Let the students develop an initial pass at the project using the techniques they know. Then, have them apply the techniques learned in this class to later iterations. They develop a reasonably large project and apply the techniques appropriately. In addition, they have an opportunity to modify and maintain their documents as they complete the project. This paper describes the approach, experiences using it, and what modifications might be useful.
Maximum Entropy Elements in the Intersection of an AffineSpace and the Cone of Positive Definite Matrices
Authors: Mihaly Bakonyi, Hugo J. Woerdeman
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

It is shown that for given positive definite $A$ and $B$ and a linear subspace $\cal{W}$ consisting of $ n \times n$ indefinite (or trivial) Hermitian matrices, there exists a unique positive definite matrix $F$ in $A+\cal{W}$ such that $F^{-1} -B \in \\cal{W}^{\perp}$. This matrix $F$ appears as the maximizer of a certain entropy function. The theorem generalizes a result on Gaussian measures with prescribed margins. Several special cases are presented, yielding new results and recovering known matrix completion results. In case $\cal{W}$ is a coordinate subspace, algorithms to find the optimal $F$ are described and numerical results are presented.
Signal integrity optimization on the pad assignment for high-speed VLSI design
Authors: Kai-Yuan Chao, D. F. Wong
Venue: Proceedings of the 1995 IEEE/ACM international conference on Computer-aided design (1995)

In this paper, an efficient method is proposed to effectively minimize both simultaneous switching noise and crosstalk that are inevitably caused by package inductance and capacitance during the design of high-speed/high-bandwidth circuits. Due to its efficiency, our algorithm can be incorporated into existing circuit floorplanning and placement schemes for the co-design of VLSI and packaging. For a set of industrial circuits/packages tested in our experiment, on the average, our method achieves a 16.8% reduction of total electrical noise when compared with the conventional design rule of thumb popularly used by circuit designers.
Rough sets
Authors: Zdzislaw Pawlak, Jerzy Grzymala-Busse, Roman Slowinski, Wojciech Ziarko
Venue: Communications of the ACM (1995)

Rough set theory, introduced by Zdzislaw Pawlak in the early 1980s [11, 12], is a new mathematical tool to deal with vagueness and uncertainty. This approach seems to be of fundamental importance to artificial intelligence (AI) and cognitive sciences, especially in the areas of machine learning, knowledge acquisition, decision analysis, knowledge discovery from databases, expert systems, decision support systems, inductive reasoning, and pattern recognition.
Inside risks: Computers as substitute soldiers?
Authors: C. C. Demchak S. E. Goodman
Venue: Communications of the ACM (1995)

Technological edge has been sought throughout military history, and today's versions of the longer lance are the computerized, integrated systems that reach pervasively into enemy space. They are intended to provide efficiencies in information gathering, processing, and disseminating so that a minimal number of humans can prevail against an enemy. The 1991 Gulf War encouraged belief in the power of electronics to defeat numerically large enemies with small friendly losses. The allies used the magic of complex electronics to pound away at an Iraqi army of over a half-million soldiers. A vision was seemingly confirmed: that those with the best computer systems will win by seeing furthest, targeting best, moving quickest, and blasting most precisely.
On the Probabilistic Interpretation of Neural Network Classifiers and Discriminative Training Criteria
Authors: Hermann Ney
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1995)

A probabilistic interpretation is presented for two important issues in neural network based classification, namely the interpretation of discriminative training criteria and the neural network outputs as well as the interpretation of the structure of the neural network. The problem of finding a suitable structure of the neural network can be linked to a number of well established techniques in statistical pattern recognition, such as the method of potential functions, kernel densities, and continuous mixture densities. Discriminative training of neural network outputs amounts to approximating the class or posterior probabilities of the classical statistical approach. This paper extends these links by introducing and analyzing novel criteria such as maximizing the class probability and minimizing the smoothed error rate. These criteria are defined in the framework of class-conditional probability density functions. We will show that these criteria can be interpreted in terms of weighted maximum likelihood estimation, where the weights depend in a complicated nonlinear fashion on the model parameters to be trained. In particular, this approach covers widely used techniques such as corrective training, learning vector quantization, and linear discriminant analysis.
Finding Regular Simple Paths in Graph Databases
Authors: Alberto O. Mendelzon, Peter T. Wood
Venue: SIAM Journal on Computing (1995)

We consider the following problem: given a labelled directed graph $G$ and a regular expression $R$, find all pairs of nodes connected by a simple path such that the concatenation of the labels along the path satisfies $R$. The problem is motivated by the observation that many recursive queries in relational databases can be expressed in this form, and by the implementation of a query language, ${\bf G}^+$, based on this observation. We show that the problem is in general intractable, but present an algorithm than runs in polynomial time in the size of the graph when the regular expression and the graph are free of conflicts. We also present a class of languages whose expressions can always be evaluated in time polynomial in the size of both the graph and the expression, and characterize syntactically the expressions for such languages.
Fast static analysis of C++ virtual function calls
Authors: David F. Bacon, Peter F. Sweeney
Venue: Proceedings of the 11th ACM SIGPLAN conference on Object-oriented programming, systems, languages, and applications (1996)

Virtual functions make code easier for programmers to reuse but also make it harder for compilers to analyze. We investigate the ability of three static analysis algorithms to improve C++ programs by resolving virtual function calls, thereby reducing compiled code size and reducing program complexity so as to improve both human and automated program understanding and analysis. In measurements of seven programs of significant size (5000 to 20000 lines of code each) we found that on average the most precise of the three algorithms resolved 71% of the virtual function calls and reduced compiled code size by 25%. This algorithm is very fast: it analyzes 3300 source lines per second on an 80 MHz PowerPC 601. Because of its accuracy and speed, this algorithm is an excellent candidate for inclusion in production C++ compilers.