ppxscal/embedding_network huggingface dataset:
Knowledge acquisition and representation techniques in scholarly communication
Authors: Brian R. Gaines, Mildred L. G. Shaw
Venue: ACM SIGDOC Asterisk Journal of Computer Documentation (1995)

Paper journals, conferences and workshops have been the major media for scholarly discourse for 300 years. However, in the 1990s access to low-cost personal computing and Internet communications is leading to radical changes in the operation of scholarly communities. Electronic publication and conferencing is becoming common in all disciplines using commonly available Internet facilities such as ftp archives, list servers, gopher and world-wide web. Some scholarly communities that had not previously achieved a critical mass have done so through the net, others have launched major collaborative projects managed through the net, and others are questioning the value of conventional conferences that are limited by being localized in space and time compared with the flexibility of continuous international electronic conferencing through the web. However, the majority of current electronic scholarly discourse emulates paper-based media in relying primarily on text and diagrams for knowledge communication. It is beginning to take advantage of some of the multimedia capabilities of electronic publishing for color diagrams, pictures, movies and sound. Hypertext and hypermedia capabilities are being used to develop webs of linked material. Concept maps and formal knowledge structures are being used to provide a framework for knowledge expression, interchange and collaborative development. This article focuses on the extension of current documentation technologies to provide knowledge-level support for scholarly communities.
Necessary Conditions for Bilevel Dynamic Optimization Problems
Authors: Jane J. Ye
Venue: SIAM Journal on Control and Optimization (1995)

In this paper we study the bilevel dynamic optimization problem, which is a hierarchy of two optimization problems where the constraint region of the upper-level problem is determined implicitly by the solution to the lower-level problem and where the upper-level decision variable is a vector while the lower-level decision variable is an admissible control function. To obtain optimality conditions, we reformulate the bilevel dynamic optimization problem as a single-level optimal control problem that involves the value function of the lower-level problem. A sensitivity analysis of the lower-level problem with respect to the perturbation in the upper-level decision variable is given, and the first-order necessary optimality conditions are derived by using nonsmooth analysis.
Architecture-oriented visualization
Authors: Mohlalefi Sefika, Aamod Sane, Roy H. Campbell
Venue: ACM SIGPLAN Notices (1996)

Tracking the changing dynamics of object-oriented frameworks[5], design patterns[7], architectural styles[8], and subsystems during the development and reuse cycle can aid producing complex systems. Unfortunately, current object-oriented programming tools are relatively oblivious to the rich architectural abstractions in a system.This paper shows that architecture-oriented visualization, the graphical presentation of system statics and dynamics in terms of its architectural abstractions, is highly beneficial in designing complex systems. In addition, the paper presents architecture-aware instrumentation, a new technique for building efficient on-line instrumentation to support architectural queries. We demonstrate the effectiveness and performance of the scheme with case studies in the design of the Choices object-oriented operating system.
Extracting task-level parallelism
Authors: Milind Girkar, Constantine D. Polychronopoulos
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1995)

Automatic detection of task-level parallelism (also referred to as functional, DAG, unstructured, or thread parallelism) at various levels of program granularity is becoming increasingly important for parallelizing and back-end compilers. Parallelizing compilers detect iteration-level or coarser granularity parallelism which is suitable for parallel computers; detection of parallelism at the statement-or operation-level is essential for most modern microprocessors, including superscalar and VLIW architectures. In this article we study the problem of detecting, expressing, and optimizing task-level parallelism, where &ldquo;task&rdquo; refers to a program statement of arbitrary granularity. Optimizing the amount of functional parallelism (by allowing synchronization between arbitrary nodes) in sequential programs requires the notion of precedence in terms of paths in graphs which incorporate control and data dependences. Precedences have been defined before in a different context; however, the definition was dependent on the ideas of parallel execution and time. We show that the problem of determining precedences statically is NP-complete. Determining precedence relationships is useful in finding the essential data dependences. We show that there exists a unique minimum set of essential data dependences; finding this minimum set is NP-hard and NP-easy. We also propose a heuristic algorithm for finding the set of essential data dependences. Static analysis of a program in the Perfect Benchmarks was done, and we present some experimental results.
Multiple paradigms in CS I
Authors: Chuck Leska, John Barr, L. A. Smith King
Venue: Proceedings of the twenty-seventh SIGCSE technical symposium on Computer science education (1996)

This paper presents an approach to introducing multiple programming language paradigms in the CS I course through the use of a single multiparadigm language. The approach uses multiple paradigms in the design and implementation of solutions to computer projects. The paper illustrates the approach by outlining a solution to a sample project which utilizes the imperative, object-oriented, and the functional paradigms.
A new approach for efficient implementation of ADA multi-tasking
Authors: Gansheng Li
Venue: ACM SIGPLAN Notices (1995)

A new approach to implement Ada multi-tasking with all tasks in a program sharing a single stack in running environment is presented. Compared with the approach of implementing a 'cactus' stack for Ada runtime memory management in which each task has its own stack but high overhead has to be paid for task context switching. The new approach presented in this paper saves runtime storage space and reduces the overhead for task context switching.
Evaluating planners, plans, and planning agents
Authors: Martha E. Pollack
Venue: ACM SIGART Bulletin (1995)

The field of AI planning has become increasingly concerned with questions of evaluation. The papers in this special issue represent several different approaches to evaluation. The first two papers present detailed analytic and experimental comparisons of particular plan generation algorithms ("planners", for short). The third and fourth papers develop formalisms for categorizing planners and the plans they produce; these formalisms are intended to provide a vocabulary for further comparative work that can bridge the gap between formal planning research and planning applications. Finally, the fifth paper argues that planners and plans can only be evaluated in the context of the planning agents that execute the plans, and presents a decision-theoretic approach to evaluating planning agents.
Grey curve and its general problems
Authors: Jinlu Liou
Venue: ACM SIGICE Bulletin (1995)

In this paper, we introduce a conception of grey curve according to the grey system theory, define the grey degree of the grey curve, and discuss the basic properties of the grey curve.
Discriminant Adaptive Nearest Neighbor Classification
Authors: Trevor Hastie, Robert Tibshirani
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1996)

Nearest neighbor classification expects the class conditional probabilities to be locally constant, and suffers from bias in high dimensions. We propose a locally adaptive form of nearest neighbor classification to try to ameliorate this curse of dimensionality. We use a local linear discriminant analysis to estimate an effective metric for computing neighborhoods. We determine the local decision boundaries from centroid information, and then shrink neighborhoods in directions orthogonal to these local decision boundaries, and elongate them parallel to the boundaries. Thereafter, any neighborhood-based classifier can be employed, using the modified neighborhoods. The posterior probabilities tend to be more homogeneous in the modified neighborhoods. We also propose a method for global dimension reduction, that combines local dimension information. In a number of examples, the methods demonstrate the potential for substantial improvements over nearest neighbor classification.
Infinity arithmetic, comparisons and J
Authors: Harvey Davies
Venue: ACM SIGAPL APL Quote Quad (1995)

The principles of infinity arithmetic are explained. There is a need to bring J arithmetic and comparisons into line with these principles. Many of the results produced by J are mathematically anomalous and do not comply with the IEEE 754 Standard for floating-point arithmetic.Some proposals to generalise the concept of comparison tolerance are presented. There are also some tentative proposals regarding safety levels and precision.The paper is oriented towards J but many of the concepts are relevant to all dialects of APL.
Supporting stored video: reducing rate variability and end-to-end resource requirements through optimal smoothing
Authors: James D. Salehi, Zhi-Li Zhang, James F. Kurose, Don Towsley
Venue: Proceedings of the 1996 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (1996)

VBR compressed video is known to exhibit significant, multiple-time-scale bit rate variability. In this paper, we consider the transmission of stored video from a server to a client across a high speed network, and explore how the client buffer space can be used most effectively toward reducing the variability of the transmitted bit rate.We present two basic results. First, we present an optimal smoothing algorithm for achieving the greatest possible reduction in rate variability when transmitting stored video to a client with given buffer size. We provide a formal proof of optimality, and demonstrate the performance of the algorithm on a set of long MPEG-1 encoded video traces. Second, we evaluate the impact of optimal smoothing on the network resources needed for video transport, under two network service models: Deterministic Guaranteed service [1, 9] and Renegotiated CBR (RCBR) service [8, 7]. Under both models, we find the impact of optimal smoothing to be dramatic.
A Novel Approach to the Numerical Solution of Boundary Value Problems on Infinite Intervals
Authors: Riccardo Fazio
Venue: SIAM Journal on Numerical Analysis (1996)

The classical numerical treatment of two-point boundary value problems on infinite intervals is based on the introduction of a truncated boundary (instead of infinity) where appropriate boundary conditions are imposed. Then, the truncated boundary allowing for a satisfactory accuracy is computed by trial. Motivated by several problems of interest in boundary layer theory, here we consider boundary value problems on infinite intervals governed by a third-order ordinary differential equation. We highlight a novel approach to define the truncated boundary. The main result is the convergence of the solution of our formulation to the solution of the original problem as a suitable parameter goes to zero. In the proposed formulation, the truncated boundary is an unknown free boundary and has to be determined as part of the solution. For the numerical solution of the free boundary formulation, a noniterative and an iterative transformation method are introduced. Furthermore, we characterize the class of free boundary value problems that can be solved noniteratively. A nonlinear flow problem involving two physical parameters and belonging to the characterized class of problems is then solved. Moreover, the Falkner--Skan equation with relevant boundary conditions is considered and representative results, obtained by the iterative transformation method, are listed for the Homann flow. All the obtained numerical results clearly indicate the effectiveness of our approach. Finally, we discuss the possible extensions of the proposed approach and for the question of a priori error analysis.
A class of logic problems solvable by linear programming
Authors: Michele Conforti, Gérard Cornuéjols
Venue: Journal of the ACM (JACM) (1995)

In propositional logic, several problems, such as satisfiability, MAX SAT and logical inference, can be formulated as integer programs. In this paper, we consider sets of clauses for which the corresponding integer programs can be solved as linear programs. We prove that balanced sets of clauses have this property.
A virtual loss-load congestion control strategy for high speed networks
Authors: Narayanan Prithviraj, Carey L. Williamson
Venue: ACM SIGCOMM Computer Communication Review (1996)

This paper evaluates a hybrid congestion control strategy called the Virtual Loss-Load model. The approach combines the leaky bucket traffic shaper (a preventive congestion control mechanism) with the loss-load model (a reactive congestion control mechanism). Simulation is used to evaluate the virtual loss-load model, and to compare its performance to that of other reactive congestion control strategies from the literature. The evaluation is done using a benchmark suite of network scenarios proposed by Kanakia, Keshav and Mishra. The performance metrics used in the evaluation are file transfer time and packet loss probability.The simulation results show that the virtual loss-load model is an effective congestion control strategy, providing performance comparable to several other reactive congestion control strategies. While transient effects due to dynamic changes in cross traffic result in significantly higher packet loss than expected in the virtual loss-load model, the parameters of the virtual loss-load model make it directly tunable to trade off packet loss and file transfer time.
Silence and secrecy: a historical sketch of the NSA
Authors: Marie A. Wright
Venue: ACM SIGSAC Review (1996)

The National Security Agency (NSA) is a silent government organization whose powerful role in controlling the design and use of non-military cryptographic algorithms has generated controversy and criticism. Because so little is known about this secretive agency, this article outlines the history of the NSA. From the rise of the American Black Chamber during the 1920s, through the growth of the Army's Signal Intelligence Service and the Navy's Radio Intelligence Division during World War II, to the establishment of the NSA in 1952, there is a recurring theme of silence and secrecy.
Efficient execution of programs with static semantics
Authors: George Becker, Neil V. Murray
Venue: ACM SIGPLAN Notices (1995)

An extension to single-threading (using each value exactly once) is presented that allows efficient execution of functional programs while maintaining their static semantics. This extension preserves the idea of only one, possibly modifying, use of a data item, and also allows any number of read-only uses. The inefficiency problem is overcome by imposing a restriction on function composition. The proposed method is based upon a static analysis of function definitions and calls. This analysis is linear in the size of function definitions, and additive between functions. Unlike approaches utilized in optimizing compilers, the proposed method can be applied even to large programs, and it guarantees the asymptotic complexity of corresponding imperative programs while obviating the need for garbage collection. An experimental functional programming language based on these ideas has been designed and implemented.
The design of RPM: an FPGA-based multiprocessor emulator
Authors: Koray Öner, Luiz A. Barroso, Sasan Iman, Jaeheon Jeong, Krishnan Ramamurthy, Michel Dubois
Venue: Proceedings of the 1995 ACM third international symposium on Field-programmable gate arrays (1995)

Recent advances in Field-Programmable Gate Arrays (FPGA) and programmable interconnects have made it possible to build efficient hardware emulation engines. In addition, improvements in Computer-Aided Design (CAD) tools, mainly in synthesis tools, greatly simplify the design of large circuits. The RPM (Rapid Prototype Engine for Multiprocessors) Project leverages these two technological advances. Its goal is to develop a common hardware platform for the emulation of multiprocessor systems with different architectures.For cost reasons, the use of FPGAs in RPM is limited to the memory controllers, while the rest of the emulator, including the processors, memories and interconnect, is built with off-the-shelf components. A flexible non-intrusive event logging mechanism is included at all levels of the memory hierarchy, making it possible to monitor the emulation in very fine detail. This paper presents the hardware design of RPM.
The difference-bit cache
Authors: Toni Juan, Tomás Lang, Juan J. Navarro
Venue: Proceedings of the 23rd annual international symposium on Computer architecture (1996)

The difference-bit cache is a two-way set-associative cache with an access time that is smaller than that of a conventional one and close or equal to that of a direct-mapped cache. This is achieved by noticing that the two tags for a set have to differ at least by one bit and by using this bit to select the way. In contrast with previous approaches that predict the way and have two types of hits (primary of one cycle and secondary of two to four cycles), all hits of the difference-bit cache are of one cycle. The evaluation of the access time of our cache organization has been performed using a recently proposed on-chip cache access model.
A Hyper Optimal Encoding Scheme for Self-Checking Circuits
Authors: Jien-Chung Lo
Venue: IEEE Transactions on Computers (1996)

A typical self-checking circuit has an unordered code encoded output. The optimal scheme needs $\lceil\, {\rm log}\, (r + 1)\, \rceil$ check bits, where r is the number of unique weights in all output patterns. A hyper optimal scheme for self-checking output encoding is proposed in this paper where the number of check bits will be further reduced in some cases. Two algorithms are presented to search for the hidden m-out-of-n code words. The hidden m-out-of-n code words are found when all unique output patterns, specified by the circuit specification, in the n selected output bits have exactly m 1s. The output bits that belong to the hidden m-out-of-n code words are then excluded from further encoding. Typically, the number of added check bits of the proposed technique ranges from 0 to $\lceil\, {\rm log}\, (p + 1)\, \rceil$, where p¿r. When hidden m-out-of-n code words exist, applying the proposed scheme usually results in significant hardware cost and delay time reduction. In the five MCNC FSM benchmark circuits that have been identified with hidden m-out-of-n code words, 10% to 41% hardware reductions are exhibited compared to the theoretically optimal separable code encoding scheme. In addition, 7% to 45% reductions in checking delays are demonstrated for the same circuits compared to the separable code encoding scheme.
Least Squares Sign-Solvability
Authors: Bryan L. Shader
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

Let $Ax=b$ be a linear system. We study the relationship between the sign pattern of the least squares solution to $Ax=b$ and the sign patterns of $A$ and $b$. The system $Ax=b$ is least squares sign-solvable if the signs of the entries in its least square solution can be determined solely from the signs of the entries of $A$ and $b$. We construct a family of least squares sign-solvable linear systems from the vertex-incidence matrices of trees. General properties of least squares sign-solvable linear systems are developed and the structure of a least squares sign-solvable system is shown to be analogous to that of sign-solvable linear systems. Square matrices whose sign pattern determines the sign pattern of its inverse have been extensively studied. We study matrices whose sign pattern determines the sign pattern of its generalized inverse.
Topological relations in the world of minimum bounding rectangles: a study with R-trees
Authors: Dimitris Papadias, Timos Sellis, Yannis Theodoridis, Max J. Egenhofer
Venue: Proceedings of the 1995 ACM SIGMOD international conference on Management of data (1995)

Recent developments in spatial relations have led to their use in numerous applications involving spatial databases. This paper is concerned with the retrieval of topological relations in Minimum Bounding Rectangle-based data structures. We study the topological information that Minimum Bounding Rectangles convey about the actual objects they enclose, using the concept of projections. Then we apply the results to R-trees and their variations, R+-trees and R*-trees in order to minimise disk accesses for queries involving topological relations. We also investigate queries that involve complex spatial conditions in the form of disjunctions and conjunctions and we discuss possible extensions.
Efficient implementation of adaptive software
Authors: Jens Palsberg, Cun Xiao, Karl Lieberherr
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1995)

Adaptive programs compute with objects, just like object-oriented programs. Each task to be accomplished is specified by a so-called propagation pattern which traverses the receiver object. The object traversal is a recursive descent via the instance variables where information is collected or propagated along the way. A propagation pattern consists of (1) a name for the task, (2) a succinct specification of the parts of the receiver object that should be traversed, and (3) code fragments to be executed when specific object types are encountered. The propagation patterns need to be complemented by a class graph which defines the detailed object structure. The separation of structure and behavior yields a degree of flexibility and understandability not present in traditional object-oriented languages. For example, the class graph can be changed without changing the adaptive program at all. We present an efficient implementation of adaptive programs. Given an adaptive program and a class graph, we generate an efficient object-oriented program, for example, in C++. Moreover, we prove the correctness of the core of this translation. A key assumption in the theorem is that the traversal specifications are consistent with the class graph. We prove the soundness of a proof system for conservatively checking consistency, and we show how to implement it efficiently.
Formal Verification for Fault-Tolerant Architectures: Prolegomena to the Design of PVS
Authors: Sam Owre, John Rushby, Natarajan Shankar, Friedrich von Henke
Venue: IEEE Transactions on Software Engineering (1995)

PVS is the most recent in a series of verification systems developed at SRI. Its design was strongly influenced, and later refined, by our experiences in developing formal specifications and mechanically checked verifications for the fault-tolerant architecture, algorithms, and implementations of a model ¿reliable computing platform¿ (RCP) for life-critical digital flight-control applications, and by a collaborative project to formally verify the design of a commercial avionics processor called AAMP5. Several of the formal specifications and verifications performed in support of RCP and AAMP5 are individually of considerable complexity and difficulty. But in order to contribute to the overall goal, it has often been necessary to modify completed verifications to accommodate changed assumptions or requirements, and people other than the original developer have often needed to understand, review, build on, modify, or extract part of an intricate verification. In this paper, we outline the verifications performed, present the lessons learned, and describe some of the design decisions taken in PVS to better support these large, difficult, iterative, and collaborative verifications.