ppxscal/embedding_network huggingface dataset:
Distributed microprogramming
Authors: Patrick M. Lenders
Venue: Proceedings of the 20th annual workshop on Microprogramming (1987)

This paper proposes the use of the microprogramming technique for synchronizing multiprocessors. The language used is an extension of CSP including the bi-io and the probe statements. We present a self-stabilizing algorithm for the generation of a two-phase clock; this algorithm is a generalization of the Dining Philosophers Problem, where n philosophers access m resources.
Emerging opportunities for theoretical computer science
Authors: Alfred V. Aho, David S. Johnson, Richard M. Karp, S. Rao Kosaraju, Catherine C. McGeoch, Christos H. Papadimitriou, Pavel Pevzner
Venue: ACM SIGACT News (1997)

The principles underlying this report can be summarized as follows:1. A strong theoretical foundation is vital to computer science.2. Theory can be enriched by practice.3. Practice can be enriched by theory.4. If we are guided by (2) and (3), the value, impact, and funding of theory will be enhanced.In order to achieve a greater synergy between theory and application, and to sustain and expand on the remarkable successes of Theory of Computing (TOC), we consider it essential to increase the impact of theory on key application areas. This requires additional financial resources in support of theory, and closer interaction between theoreticians and researchers in other areas of computer science and in other disciplines.The report does not make a detailed assessment of the overall state of theoretical computer science or fully chronicle the achievements of this field. Instead, it has the specific objective of recommending ways to harness these remarkable achievements for the solution of challenging problems emerging from new developments such as the information superhighway.Section 1 describes the events leading up to this report and delineates the report's objectives. Section 2 establishes the context for the report. It traces the history of TOC, describes the impact that TOC has achieved in the areas of core theory and fundamental algorithms, points out the differences between these areas and application-oriented theory, and calls for an intensified effort to bring the methods of TOC to bear on applications. It then goes on to define the four main categories into which our recommen- dations fall: building bridges between theory and applications, algorithm engineering, communication, and education. Section 3 discusses some specific opportunities for stimulating interactions between TOC and applied areas. Section 4 proposes an applied research initiative, Information Access in a Globally Distributed Environment, which identifies an exciting current technological area that we believe presents challenging opportunities for excellent theoretical work. Section 5 proposes a second applied research initiative, The Algorithmic Stockroom, that would exploit and extend the body of theoretical knowledge in the field of algorithms. Section 6 proposes a broadening in graduate education with two purposes in mind: to better prepare theoreticians to interact creatively with practitioners, and to provide future practitioners with the background they will need to benefit from this exchange.
Progress in modular simulation environments
Authors: Charles R. Standridge, James F. Kelly, Thomas Kelley, Jack Walther
Venue: Proceedings of the 28th conference on Winter simulation (1996)

How each simulationist can design and implement software tailored for each particular simulation project is addressed by modular simulation environments. The requirements of such environments are derived from the needs of four distinct types of users. Inter-tool modularity deals with how data flows between a non homogeneous set of software tools that can be changed on an ad hoc basis. Both simulation specific and widely applicable software tools may be used. The organization and management of simulation inputs and results to achieve this goal is important. Intra-tool modularity has to do with supporting simulation project tasks in a modular fashion. Modular modeling is well established. Possibilities for modular animation and the modular use of widely applicable tools, specifically spreadsheets, are discussed. An example modular simulation environment is given.
Constrained Maximum Likelihood
Authors: Ronald Schoenberg
Venue: Computational Economics (1997)

Constrained Maximum Likelihood (CML), developed at Aptech Systems, generates maximum likelihood estimates with general parametric constraints (linear or nonlinear, equality or inequality), using the sequential quadratic programming method. CML computes two classes of confidence intervals, by inversion of the Wald and likelihood ratio statistics, and by simulation. The inversion techniques can produce misleading test sizes, but Monte Carlo evidence suggests this problem can be corrected under certain circumstances.
Anomaly detection: a soft computing approach
Authors: T. Y. Lin
Venue: Proceedings of the 1994 workshop on New security paradigms (1994)

Computer are finite discrete machines, the set of real numbers is an infinite continuum. So real numbers in computers are approximation. Rough set theory is the underlying mathematics. A &ldquo;computer&rdquo; version of Weistrass theorem states that every sequence, within the radius of error, repeats certain terms infinitely many times. In terms of applications, the theorem guarantees that the audit trail has repeating patterns. Examining further, based on fuzzy-rough set theory, hidden fuzzy relationships (rules) in audit data are uncovered. The information about the repeating data and fuzzy relationships reflect &ldquo;unconscious patterns&rdquo; of user's habits. They are some deeper &ldquo;signatures&rdquo; of computer users, which provide a foundation to detect abuses and misuses of computer systems. A &ldquo;sliding window information system&rdquo; is used to illustrate the detection of a &ldquo;simple&rdquo; virus attack. The complexity problem is believed to be controllable via rough set representation of data.
Toward an informational model of the organization: communication transmission metrics
Authors: John H. Lundin, Lawrence L. Schkade
Venue: ACM SIGGROUP Bulletin (1997)

Organizations are spending an increasing amount of their budgets on the communication infrastructure. At the same time, the solutions are becoming less defined with more technologies available and accessible. Organizations must develop an informational model and a comprehensive set of metrics to measure the flows of information within and between organizations. This paper will propose and explain a framework for communication transmission metrics as a portion of the informational model. The contribution of this paper is the structure, variable categories and the integration of the metrics for representing the communication infrastructure.
Very concurrent mark- -sweep garbage collection without fine-grain synchronization
Authors: Lorenz Huelsbergen, Phil Winterbottom
Venue: ACM SIGPLAN Notices (1999)

We describe a new incremental algorithm for the concurrent reclamation of a program's allocated, yet unreachable, data. Our algorithm is a variant of mark- amp;-sweep collection that---unlike prior designs---runs mutator, marker, and sweeper threads concurrently without explicit fine-grain synchronization on shared-memory multiprocessors. A global, but infrequent, synchronization coordinates the per-object coloring marks used by the three threads; fine-grain synchronization is achieved without locking via the basic memory consistency guarantees commonly provided by multiprocessor hardware. We have implemented two versions of this algorithm (called VCGC): in the Inferno operating system and in the SML/NJ ML compiler. Measurements, compared to a sequential generational collector, indicate that VCGC can substantially reduce worst-case pause latencies as well as reduce overall memory usage. We remark that the degrees of freedom on the rates of marking and sweeping enable exploration of a range of resource tradeoffs, but makes "optimal" tuning for even a small set of applications difficult.
Forth as a robotics language: part two
Authors: Paul Frenger
Venue: ACM SIGPLAN Notices (1997)

This is the second part of a two-part paper describing the author's recent experiences with robot control systems. In part one, the three principal robotics language philosophies were illustrated. This was followed by a discussion of unconventional languages for robot control, namely PostScript and Java. In this installment, the author describes how he used Forth as an object oriented programming language to develop a multiprocessor android control network. Some interesting Forth derivatives will be presented at the end.
An experiment in simulation interoperability
Authors: Gary N. Bundy, David W. Seidel, Ben C. King, Carl D. Burke
Venue: Proceedings of the 28th conference on Winter simulation (1996)

The AWSIM Interoperability with ModSAF (AIM) program is investigating interfacing traditional constructive simulations with virtual simulations. The program addresses a number of issues involved in this interoperability. As a mechanism for exploring these issues, ModSAF is used to create a detailed window into an AWSIM exercise; modeling of AWSIM aircraft entering the window is transferred to ModSAF. A prototype was developed to investigate the practical aspects of the interface issues. Knowledge, algorithms, and software developed in this program will support future Air Force wargame development.
Metric-Based Symmetric Rank-One Updates
Authors: B. Smith, J. L. Nazareth
Venue: Computational Optimization and Applications (1997)

Metric-based SR1 updates which are stabilized by a variational relaxation of the quasi-Newton relation are examined. This investigation reveals an interesting and surprising connection to the origin of quasi-Newton methods as first formulated by Davidon [1]. An extended version of Davidon&lsquo;s original direct prediction SR1 update is shown to be self-complementary and to possess a finite termination property on quadratics, and limited-memory versions of the update are shown to be globally convergent. Variants of this update are tested numerically and compared to several other metric-based SR1 variants and the BFGS update. Finally, metric-based stabilizations of the SR1 update are critiqued in general, and a promising new model-based strategy recently developed is briefly described.
Interface timing verification drives system design
Authors: Ajay J. Daga, Peter R. Suaris
Venue: Proceedings of the 34th annual Design Automation Conference (1997)

System design, i.e. the design of board-level circuits andsystems-on-a-chip, focuses on the integration of off-the-shelf andapplication-specific VLSI components. A key aspect of systemdesign is to ensure the satisfaction of component interface timingrequirements. This is necessary for the correct exchange ofinformation among components on a system. We present amethodology for the interface timing verification and subsequenttiming-driven floorplanning of systems. We present results on theapplication of this methodology to real-world circuits.
A Traffic Generator for Testing Communication Systems: Presentation,Implementation and Performance
Authors: Nedo Celandroni, Erina Ferro, Francesco Potorti
Venue: Real-Time Systems (1997)

This paper presents a multi-application traffic generator (MTG), aimed at the generation of packets over a LAN. The generated traffic simulates the one produced by a number of both isochronous and anisochronous applications, thus allowing the measurement of a number of parameters relevant to the communication network. From a test point of view, data generated by the MTG system is equivalent to data generated by real applications spread over a LAN. The MTG system is presented, its implementation is described, some figures relevant to the MTG performance are shown, and the statistical analysis which can be performed on the recorded data is briefly introduced. The user manual of the MTG system is referenced in (Celandroni, Ferro, and Potorti 1995).
Maximum Matching on Boltzmann Machines
Authors: Xin Yao
Venue: Neural Processing Letters (1998)

The Boltzmann machine is one of widely used neural network models used to cope with difficult combinatorial optimisation problems. It has been used to find near optimum solutions to such hard problems as graph partitioning and the Travelling Salesman problem. However, very little is known about the time complexity of solving combinatorial optimisation problems on Boltzmann machines. This issue is important because it will help us better understand the power of Boltzmann machines in dealing with hard problems. This paper studies the time complexity of maximum matching in a graph on Boltzmann machines. It is shown that some widely-used Boltzmann machines cannot find a maximum matching in average time polynomial in the number of nodes of the graph although there are conventional deterministic algorithms which solve the problem in polynomial time. On the other hand, this paper also shows that a simpler model of Boltzmann machines, with the &rsquo;temperature&lsquo; parameter fixed at some constant, can find a near maximum matching in polynomial average time.
M-TCP: TCP for mobile cellular networks
Authors: Kevin Brown, Suresh Singh
Venue: ACM SIGCOMM Computer Communication Review (1997)

Transport connections set up over wireless links are frequently plagued by problems such as - high bit error rate (BER), frequent disconnections of the mobile user, and low wireless bandwidth that may change dynamically. In this paper, we study the effects of frequent disconnections and low variable bandwidth on TCP throughput and propose a protocol that addresses this problem. We discuss the implementation (in NetBSD) of our protocol called M-TCP and compare its performance against other mobile TCP implementations. We show that M-TCP has two significant advantages over other solutions: (1) it maintains end-to-end TCP semantics and, (2) it delivers excellent performance for environments where the mobile encounters periods of disconnection.
High-speed policy-based packet forwarding using efficient multi-dimensional range matching
Authors: T. V. Lakshman, D. Stiliadis
Venue: ACM SIGCOMM Computer Communication Review (1998)

The ability to provide differentiated services to users with widely varying requirements is becoming increasingly important, and Internet Service Providers would like to provide these differentiated services using the same shared network infrastructure. The key mechanism, that enables differentiation in a connectionless network, is the packet classification function that parses the headers of the packets, and after determining their context, classifies them based on administrative policies or real-time reservation decisions. Packet classification, however, is a complex operation that can become the bottleneck in routers that try to support gigabit link capacities. Hence, many proposals for differentiated services only require classification at lower speed edge routers and also avoid classification based on multiple fields in the packet header even if it might be advantageous to service providers. In this paper, we present new packet classification schemes that, with a worst-case and traffic-independent performance metric, can classify packets, by checking amongst a few thousand filtering rules, at rates of a million packets per second using range matches on more than 4 packet header fields. For a special case of classification in two dimensions, we present an algorithm that can handle more than 128K rules at these speeds in a traffic independent manner. We emphasize worst-case performance over average case performance because providing differentiated services requires intelligent queueing and scheduling of packets that precludes any significant queueing before the differentiating step (i.e., before packet classification). The presented filtering or classification schemes can be used to classify packets for security policy enforcement, applying resource management decisions, flow identification for RSVP reservations, multicast look-ups, and for source-destination and policy based routing. The scalability and performance of the algorithms have been demonstrated by implementation and testing in a prototype system.
The gestalt of scientific programming: problem, model, method, implementation, assessment
Authors: Joseph L. Zachary
Venue: Proceedings of the twenty-eighth SIGCSE technical symposium on Computer science education (1997)

The process of solving a problem in computational science neither begins nor ends with designing and writing a computer program. The process entails isolating the problem, devising a mathematical model, identifying a computational method, producing an implementation, and assessing the solution. Unfortunately, the introductory programming courses taken by science and engineering students frequently focus only on implementation issues. As a result, such students are often ill-equipped to solve computational problems.We have created a course and written an accompanying textbook that present an introduction to scientific programming. Both are organized around the process for solving computational science problems sketched above. In this paper we illustrate this approach by describing two representative problems from the course and textbook. Along the way, we present Java applets that were designed to illustrate some of the ideas that underlie the two problems.
Reducing the performance impact of instruction cache misses by writing instructions into the reservation stations out-of-order
Authors: Jared Stark, Paul Racunas, Yale N. Patt
Venue: Proceedings of the 30th annual ACM/IEEE international symposium on Microarchitecture (1997)

In conventional processors, each instruction cache fetch brings in a group of instructions. Upon encountering an instruction cache miss, the processor will wait until the instruction cache miss is serviced before continuing to fetch any new instructions. This paper presents a new technique, called out-of-order issue, which allows the processor to temporarily ignore the instructions associated with the instruction cache miss. The processor attempts to fetch the instructions that follow the group of instructions associated with the miss. These instructions are then decoded and written into the processor's reservation stations. Later, after the instruction cache miss has been serviced, the instructions associated with the miss are decoded and written into the reservation stations. (We use the term issue to indicate the act of writing instructions into the reservation stations. With this technique, instructions are not written into the reservation stations in program order. Hence, the term out-of-order issue.) In this paper, we introduce the concept of out-of-order issue, describe its implementation, and present some initial data showing the performance gains possible with out-of-order issue.
A refinement calculus for the synthesis of verified hardware descriptions in VHDL
Authors: Peter T. Breuer, Carlos Kloos Delgado, Andrés López Marín, Natividad Martínez Madrid, Luis Sánchez Fernández
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1997)

A formal refinement calculus targeted at system-level descriptions in the IEEE standard hardware description language VHDL is described here. Refinement can be used to develop hardware description code that is &ldquo;correct by construction&rdquo;. the calculus is closely related to a Hoare-style programming logic for VHDL and real-time systems in general. That logic and a semantics for a core subset of VHDL are described. The programming logic and the associated refinement calculus are shown to be complete. This means that if there is a code that can be shown to implement a given specification, then it will be derivable from the specification via the calculus.
Delivering Dependable Telecommunication Services Using Off-the-Shelf System Components
Authors: Y. Levendel
Venue: Journal of Electronic Testing: Theory and Applications (1998)

For decades, traditional telecommunication systems have reliably delivered telephony services using expensive equipment and software. In spite of large R D expenses, the end customer costs remained low due to the amortization of the equipment over a large population of users. With the advent of low cost and high performance computers, it has become conceivable to deliver similar and more powerful services using systems constructed with off-the-shelf components. The only obstacle remaining to make this a reality is the ability of system designers to provide rationable dependability of such systems. This paper illustrates one possible avenue for performing this task and identifies a condition that is necessary for the deployment of such systems, namely the components must in turn provide measures of survivability.
Combinatory formulations of concurrent languages
Authors: N. Raja, R. K. Shyamasundar
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1997)

We design a system with six Basic Combinators and prove that it is powerful enough to embed the full asynchronous &pgr;-calculus, including replication. Our theory for constructing Combinatory Versions of concurrent languages is based on a method, used by Quine and Bernays, for the general elimination of variables in linguistic formalisms. Our combinators are designed to eliminate the requirement of names that are bound by aninput prefix. They also eliminate the need for input prefix, output prefix, and the accompanying mechanism of substitution. We define a notion of bisimulation for the combinatory version and show that the combinatory version preserves the semantics of the original calculus. One of the distinctive features of the approach is that it can be used to rework several process algebras in order to derive equivalent combinatory versions.
Probabilistic Analysis of Gaussian Elimination Without Pivoting
Authors: Man-Chung Yeung, Tony F. Chan
Venue: SIAM Journal on Matrix Analysis and Applications (1997)

The numerical instability of Gaussian elimination is proportional to the size of the $L$ and $U$ factors that it produces. The worst-case bounds are well known. For the case without pivoting, breakdowns can occur and it is not possible to provide {a priori} bounds for $L$ and $U$. For the partial pivoting case, the worst-case bound is $O(2^m)$, where $m$ is the size of the system. Yet these worst-case bounds are seldom achieved, and in particular Gaussian elimination with partial pivoting is extremely stable in practice. Surprisingly, there has been relatively little theoretical study of the ``average'' case behavior. The purpose of our paper is to provide a probabilistic analysis of the case without pivoting. The distribution we use for the entries of $A$ is the normal distribution with mean $0$ and unit variance. We first derive the distributions of the entries of $L$ and $U$. Based on this, we prove that the probability of the occurrence of a pivot less than $\epsilon$ in magnitude is $O(\epsilon)$. We also prove that the probabilities ${\rm Prob}(||U||_\infty/||A||_\infty > m^{2.5})$ and ${\rm Prob}(||L||_\infty > m^{3})$ decay algebraically to zero as $m$ tends to infinity. Numerical experiments are presented to support the theoretical results.