ppxscal/embedding_network huggingface dataset:
And/Or Programs: A New Approach to Structured Programming
Authors: David Harel
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1980)

A simple tree-like programming/specification language is presented. The central idea is the dividing of conventional programming constructs into the two classes of and and or subgoaling, the subgoal tree itself constituting the program. Programs written in the language can, in general, be both nondeterministic and parallel. The syntax and semantics of the language are defined, a method for verifying programs written in it is described, and the practical significance of programming in the language assessed. Finally, some directions for further research are indicated.
March tests for word-oriented memories
Authors: A. J. van de Goor, I. B. S. Tlili
Venue: Proceedings of the conference on Design, automation and test in Europe (1998)

Most memory test algorithms are optimized tests for a particular memory technology and a particular set of fault models, under the assumption that the memory is bit-oriented; i.e., read and write operations affect only a single bit in the memory. Traditionally, word-oriented memories have been tested by repeated application of a test for bit-oriented memories whereby a different data background (which depends on the used intra-word fault model) is used during each iteration. This results in time inefficiencies and limited fault coverage. A new approach for testing word-oriented memories is presented, distinguishing between inter-word and intra-word faults and allowing for a systematic way of converting tests for bit-oriented memories to tests for word-oriented memories. The conversion consists of concatenating the bit-oriented test for inter-word faults with a test for intra-word faults. This approach results in more efficient tests with complete coverage of the targeted faults. Because most memories have an external data path which is wider than one bit, word-oriented memory tests are very important.
On polynomial approximation to the shortest lattice vector length
Authors: Ravi Kumar, D. Sivakumar
Venue: Proceedings of the twelfth annual ACM-SIAM symposium on Discrete algorithms (2001)

We obtain a 2&Ogr;(n/&isin;) time algorithm to approximate the length of the shortest vector in an n-dimensional lattice to within a factor of n3+&isin;.
Accelerating shared virtual memory via general-purpose network interface support
Authors: Angelos Bilas, Dongming Jiang, Jaswinder Pal Singh
Venue: ACM Transactions on Computer Systems (TOCS) (2001)

Clusters of symmetric multiprocessors (SMPs) are important platforms for high-performance computing. With the success of hardware cache-coherent distributed shared memory (DSM), a lot of effort has also been made to support the coherent shared-address-space programming model in software on clusters. Much research has been done in fast communication on clusters and in protocols for supporting software shared memory across them. However, the performance of software virtual memory (SVM) is still far from that achieved on hardware DSM systems. The goal of this paper is to improve the performance of SVM on system area network clusters by considering communication and protocol layer interactions. We first examine what are the important communication system bottlenecks that stand in the way of improving parallel performance of SVM clusters; in particular, which parameters of the communication architecture are most important to improve further relative to processor speed, which ones are already adequate on modern systems for most applications, and how will this change with technology in the future. We find that the most important communication subsystem cost to improve is the overhead of generating and delivery interrupts for asynchronous protocol processing. Then we proceed to show, that by providing simple and general support for asynchronous message handling in a commodity network interface (NI) and by altering SVM protocols appropriately, protocol activity can be decoupled from asynchronous message handling, and the need for interrupts or polling can be eliminated. The NI mechanisms needed are generic, not SVM-dependent. We prototype the mechanisms and such a synchronous home-based LRC protocol, called GeNIMA (GEneral-purpose Network Interface support for shared Memory Abstractions), on a cluster of SMPs with a programmable NI. We find that the performance improvements are substantial, bringing performance on a small-scale SMP cluster much closer to that of hardware-coherent shared memory for many applications, and we show the value of each of the mechanisms in different applications.
Exploiting redundancy in question answering
Authors: Charles L. A. Clarke, Gordon V. Cormack, Thomas R. Lynam
Venue: Proceedings of the 24th annual international ACM SIGIR conference on Research and development in information retrieval (2001)

Our goal is to automatically answer brief factual questions of the form ``When was the Battle of Hastings?'' or ``Who wrote The Wind in the Willows?''. Since the answer to nearly any such question can now be found somewhere on the Web, the problem reduces to finding potential answers in large volumes of data and validating their accuracy. We apply a method for arbitrary passage retrieval to the first half of the problem and demonstrate that answer redundancy can be used to address the second half. The success of our approach depends on the idea that the volume of available Web data is large enough to supply the answer to most factual questions multiple times and in multiple contexts. A query is generated from a question and this query is used to select short passages that may contain the answer from a large collection of Web data. These passages are analyzed to identify candidate answers. The frequency of these candidates within the passages is used to ``vote'' for the most likely answer. The approach is experimentally tested on questions taken from the TREC-9 question-answering test collection. As an additional demonstration, the approach is extended to answer multiple choice trivia questions of the form typically asked in trivia quizzes and television game shows.
Pricing considerations in video-on-demand systems (poster session)
Authors: Prithwish Basu, Thomas D. C. Little
Venue: Proceedings of the eighth ACM international conference on Multimedia (2000)

Video-on-demand (VoD) has been an active area of research for the past few years in the multimedia research community. However, there have not been many significant commercial deployments of VoD owing to the inadequacy of per user bandwidth and the lack of a good business model.1 Significant research efforts have been directed towards reduction of network bandwidth requirements, improvement of server utilization, and minimization of start-up latency. In this paper, we investigate another aspect of VoD systems which has been largely neglected by the research community, namely, pricing models for VoD systems. We believe that the price charged to a user for an on-demand video stream should influence the rate of user arrivals into the VoD system and in turn should depend upon quality-of-service (QoS) factors such as initial start-up latency. We briefly describe some simple pricing models and analyze the tradeoffs involved in such scenarios from a profit maximization point of view. We further explore secondary content insertion (ad-insertion) which was proposed elsewhere [1] not only as a technique for reducing the resource requirements at the server and the network, but also as a means of subsidizing VoD content to the end user. We treat the rate of ad insertion as another QoS factor and demonstrate how it can influence the price of movie delivery.
Bounds on Functions with \sl N-th order BandlimitedHankel Transforms
Authors: Nikolaos E. Myridis, Christodoulos Chamzas
Venue: Multidimensional Systems and Signal Processing (2000)

N-th order Hankel Transforms are important for the reconstruction in Magnetic Resonance Imaging (MRI), CAT etc. In this contribution we derive new bounds on functions, which have bandlimited their n-th order Hankel Transform.
The emergence of a profession
Authors: Alex Orden
Venue: Communications of the ACM (1967)

Computer programming deals with an enormous variety of activities and is carried on by people with a great variety of backgrounds. It seems clear that part but not all of this activity is evolving toward a distinct professional field, but that the scope of this emerging profession, and some of its economic, social, and educational characteristics are as yet by no means well defined. In this paper, these issues are examined and some opinions about them are expressed.
LEneS: task scheduling for low-energy systems using variable supply voltage processors
Authors: Flavius Gruian, Krzysztof Kuchcinski
Venue: Proceedings of the 2001 Asia and South Pacific Design Automation Conference (2001)

The work presented in this paper addresses minimization of the energy consumption of a system during system-level design. The paper focuses on scheduling techniques for architectures containing variable supply voltage processors, running dependent tasks. We introduce our new approach for Low-Energy Scheduling (LEneS) and compare it to two other scheduling methods. LEneS is based on a list-scheduling heuristic with dynamic recalculation of priorities, and assumes a given allocation and assignment of tasks to processors. Our approach minimizes the energy by choosing the best combination of supply voltages for each task running on its processor. The set of experiments we present shows that, using the LEneS approach, we can achieve up to 28% energy savings for the tightest deadlines, and up to 77% energy savings when these deadlines are relaxed by 50%.
Mobile values, new names, and secure communication
Authors: Martín Abadi, Cédric Fournet
Venue: ACM SIGPLAN Notices (2001)

We study the interaction of the "new" construct with a rich but common form of (first-order) communication. This interaction is crucial in security protocols, which are the main motivating examples for our work; it also appears in other programming-language contexts. Specifically, we introduce a simple, general extension of the pi calculus with value passing, primitive functions, and equations among terms. We develop semantics and proof techniques for this extended language and apply them in reasoning about some security protocols.
On ACM special interest groups and committees
Authors: Peter J. Denning
Venue: Communications of the ACM (1971)

This report has been written to explain the nature, purposes, and organization of the Special Interest Groups (SIGS) and Special Interest Committees (SICS) of ACM, and to summarize SIG/SIC activity during the period August 1, 1970, to August 1, 1971.
Relationship Between Backward Stochastic Differential Equations and Stochastic Controls: A Linear-Quadratic Approach
Authors: Michael Kohlmann, Xun Yu Zhou
Venue: SIAM Journal on Control and Optimization (2000)

It is well known that backward stochastic differential equations (BSDEs) stem from the study on the Pontryagin type maximum principle for optimal stochastic controls. A solution of a BSDE hits a given terminal value (which is a random variable) by virtue of an it additional martingale term and an indefinite initial state. This paper attempts to explore the relationship between BSDEs and stochastic controls by interpreting BSDEs as some stochastic optimal control problems. More specifically, associated with a BSDE, a new stochastic control problem is introduced with the same dynamics but a definite given initial state. The martingale term in the original BSDE is regarded as the control, and the objective is to minimize the second moment of the difference between the terminal state and the terminal value given in the BSDE. This problem is solved in a closed form by the stochastic linear-quadratic (LQ) theory developed recently. The general result is then applied to the Black--Scholes model, where an optimal mean-variance hedging portfolio is obtained explicitly in terms of the option price. Finally, a modified model is investigated, where the difference between the state and the expectation of the given terminal value at any time is taken into account.
Simultaneous shield insertion and net ordering under explicit RLC noise constraint
Authors: Kevin M. Lepak, Irwan Luwandi, Lei He
Venue: Proceedings of the 38th annual Design Automation Conference (2001)

For multiple coupled RLC nets, we formulate the min-area simultaneous shield insertion and net ordering SINO/NB-&ngr; problem to satisfy the given noise bound. We develop an efficient and conservative model to compute the peak noise, and apply the noise model to a simulated-annealing (SA) based algorithm for the SINO/NB-&ngr; problem. Extensive and accurate experiments show that the SA-based algorithm is efficient, and always achieves solutions satisfying the given noise bound. It uses up to 71\% and 30\% fewer shields when compared to a greedy based shield insertion algorithm and a separated shield insertion and net ordering algorithm, respectively. To the best of our knowledge, it is the first work that presents an in-depth study on the min-area SINO problem under an explicit noise constraint.
Turnover among DP personnel: a casual analysis
Authors: Kathryn M. Bartol
Venue: Communications of the ACM (1983)

Four variables suggested by previous research were included in a proposed causal model of turnover among computer specialists. When tested using correlational analysis, three of the variables were significant inverse predictors of turnover. A fourth variable was also inversely related to turnover, but not significantly so. Path analysis supports the proposed causal model and suggest turnover indirectly through its influence on the other model variables.
α-coral: a multigrain, multithreaded processor architecture
Authors: Mark N. Yankelevsky, Constantine D. Polychronopoulos
Venue: Proceedings of the 15th international conference on Supercomputing (2001)

Recently popularized hardware multithreading (HMT) architectures, such as SMT, Multiscalar and Terra do not provide flexible and efficient methods of thread management and synchronization in hardware. The &agr;-Coral architecture is a tool for investigation of a more dynamic approach to thread management. Unlike other architectures, there are no strict requirements on timing and size of threads, and no static partitioning of resources. &agr;-Coral provides for simultaneous multiprogramming and multithreading environment, which is mostly managed in hardware. To other architectures, &agr;-Coral adds on demand register allocation, fast variable size thread creation and destruction, as well as quick synchronization through a shared register file. While other architectures attempt to port existing compilers, the &agr;-Coral architecture is supported by a custom compiler system. This system provides for a simple method of mapping hierarchical internal representation of the program to variable size threads. This paper examines a new approach to hardware multithreading, involving minimal extensions to the instruction set of conventional RISC superscalar architectures. The &agr;-Coral architecture and compiling support introduce a multi-grain multithreaded architecture which extends wide-superscalar processor cores to support hierarchical multithreading. A simulator was developed and results are presented to demonstrate the feasibility of our design approach.
Positivity and norms
Authors: F. L. Bauer
Venue: Communications of the ACM (1975)

Following some lines of joint work with A.S. Householder, the character and use of algebraic methods in the theory of norms is demonstrated. New results concerning norms with values in an Archimedian vector lattice (not necessarily being totally ordered) are given, in particular for the generalization of order unit norms, L-norms and M-norms. An example of application to operator norms is given concerning contraction properties of positive operators.
The conversion of limited-entry decision tables to optimal and near-optimal flowcharts: two new algorithms
Authors: M. Verhelst
Venue: Communications of the ACM (1972)

Two new algorithms for deriving optimal and near-optimal flowcharts from limited entry decision tables are presented. Both take into account rule frequencies and the time needed to test conditions. One of the algorithms, called the optimum-finding algorithm, leads to a flowchart which truly minimizes execution time for a decision table in which simple rules are already contracted to complex rules. The other one, called the optimum-approaching algorithm, requires many fewer calculations but does not necessarily produce the optimum flowchart. The algorithms are first derived for treating decision tables not containing an ELSE-rule, but the optimum-approaching algorithm is shown to be equally valid for tables including such a rule. Both algorithms are compared with existing ones and are applied to a somewhat large decision table derived from a real case. From this comparison two conclusions are drawn. (1) The optimum-approaching algorithm will usually lead to better results than comparable existing ones and will not require more, but usually less, computation time. (2) In general, the greater computation effort needed for applying the optimum-finding algorithm will not be justified by the small reduction in execution time obtained.
The Role of Holistic Paradigms in Handwritten Word Recognition
Authors: Sriganesh Madhvanath, Venu Govindaraju
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2001)

The Holistic paradigm in handwritten word recognition treats the word as a single, indivisible entity and attempts to recognize words from their overall shape, as opposed to their character contents. In this survey, we have attempted to take a fresh look at the potential role of the Holistic paradigm in handwritten word recognition. The survey begins with an overview of studies of reading which provide evidence for the existence of a parallel holistic reading process in both developing and skilled readers. In what we believe is a fresh perspective on handwriting recognition, approaches to recognition are characterized as forming a continuous spectrum based on the visual complexity of the unit of recognition employed and an attempt is made to interpret well-known paradigms of word recognition in this framework. An overview of features, methodologies, representations, and matching techniques employed by holistic approaches is presented.
A Direct Interpretation of Dynamic Images with Camera and Object Motions for Vision Guided Robot Control
Authors: Koichiro Deguchi
Venue: International Journal of Computer Vision (2000)

A general scheme to represent the relation between dynamic images and camera and/or object motions is proposed for applications to visual control of robots. We consider the case where a moving camera observes moving objects in a static scene. The camera obtains images of the objects moving within the scene. Then, the possible combinations of the camera and the objects' poses and the obtained images are not arbitrary but constrained to each other. Here we represent this constraint as a lower dimensional hypersurface in the product space of the whole combination of their motion control parameters and image data. The visual control is interpreted as to find a path on this surface leading to their poses where a given goal image will be obtained. In this paper, we propose a visual control method to utilize tangential properties of this surface. First, we represent images with a composition of a small number of &ldquo;eigen images&rdquo; by using K-L (Karhunen-Lo&egrave;ve) expansion. Then, we consider to reconstruct the eigen space (the eigen image space) to achieve efficient and straightforward controls. Such reconstruction of the space results in the constraint surface being mostly flat within the eigen space. By this method, visual control of robots in a complex configuration is achieved without image processing to extract and correspond image features in dynamic images. The method also does not need camera or hand-eye calibrations. Experimental results of visual servoing with the proposed method show the feasibility and applicability of our newly proposed approach to a simultaneous control of camera self-motion and object motions.
Climate data assimilation on a massively parallel Supercomputer
Authors: Hong Q. Ding, Robert D. Ferraro
Venue: Proceedings of the 1996 ACM/IEEE conference on Supercomputing (CDROM) (1996)

We have designed and implemented a set of highly efficient and highly scalable algorithms for an unstructured computational package, the PSAS data assimilation package, as demonstrated by detailed performance analysis of systematic runs on up to 512-nodes of an Intel Paragon. The preconditioned Conjugate Gradient solver achieves a sustained 18 Gflops performance. Consequently, we achieve an unprecedented 100-fold reduction in time to solution on the Intel Paragon over a single head of a Cray C90. This not only exceeds the daily performance requirement of the Data Assimilation Office at NASA's Goddard Space Flight Center, but also makes it possible to explore much larger and challenging data assimilation problems which are unthinkable on a traditional computer platform such as the Cray C90.
QuickCheck: a lightweight tool for random testing of Haskell programs
Authors: Koen Claessen, John Hughes
Venue: Proceedings of the fifth ACM SIGPLAN international conference on Functional programming (2000)

Quick Check is a tool which aids the Haskell programmer in formulating and testing properties of programs. Properties are described as Haskell functions, and can be automatically tested on random input, but it is also possible to define custom test data generators. We present a number of case studies, in which the tool was successfully used, and also point out some pitfalls to avoid. Random testing is especially suitable for functional programs because properties can be stated at a fine grain. When a function is built from separately tested components, then random testing suffices to obtain good coverage of the definition under test.
Why license when you can rent? Risks and rewards of the application service provider model
Authors: Ravi Patnayakuni, Nainika Seth
Venue: Proceedings of the 2001 ACM SIGCPR conference on Computer personnel research (2001)

The confluence of several developments in technology and trends in the business environment has led to the emergence of new outsourcing model, the Application Service Provider (ASP). In this paper we draw upon outsourcing literature to understand the factors that are likely to influence the adoption of the ASP model. An initial research model is developed based on factors identified from economic and social perspectives used in outsourcing literature.
Investigation of a new analytical method for numerical derivative evaluation
Authors: R. D. Wilkins
Venue: Communications of the ACM (1964)

A recently proposed analytical approach to numerical derivative evaluation is discussed. The technique is shown to be both accurate and easy to apply, though certain indicated modifications are required. Its use should greatly facilitate the writing and debugging of programs requiring derivatives of highly complex functions.