ppxscal/embedding_network huggingface dataset:
An undergraduate concentration in networking and distributed systems
Authors: Margaret M. Reek
Venue: Proceedings of the twentieth SIGCSE technical symposium on Computer science education (1989)

This paper describes our experiences at Rochester Institute of Technology in establishing an undergraduate computer science concentration in networking and distributed systems. The concentration course sequence, prerequisite requirements, individual course structure, lab environment and student projects are discussed.
Factoring rational polynomials over the complexes
Authors: C. Bajaj, J. Canny R. Garrity, J. Warren
Venue: Proceedings of the ACM-SIGSAM 1989 international symposium on Symbolic and algebraic computation (1989)

We give NC algorithms for determining the number and degrees of the absolute factors (factors irreducible over the complex numbers C) of a multi-variate polynomial with rational coefficients. NC is the class of functions computable by logspace-uniform Boolean circuits of polynomial size and polylogarithmic depth. The measures of size of the input polynomial are its degree d, coefficient length c, number of variables n, and for sparse polynomials, the number of non-zero coefficients s. For the general case, we give a random (Monte-Carlo) NC algorithm in these input measures. If n is fixed, or if the polynomial is dense, we give a deterministic NC algorithm. The algorithm also works in random NC for polynomials represented by straight-line programs, provided the polynomial can be evaluated at integer points in NC. Finally, we discuss a method for obtaining an approximation to the coefficients of each factor whose running time is polynomial in the size of the original (dense) polynomial. These methods rely on the fact that the connected components of a complex hypersurface P(z1&hellip;,zn) = 0 minus its singular points correspond to the absolute factors of P.
Learning recursion as a concept and as a programming technique
Authors: Susan Wiedenbeck
Venue: ACM SIGCSE Bulletin (1988)

Two experiments on learning recursion and iteration were carried out. The first studied learning of the mathematical concept of recursion by having subjects compute mathematical functions by analogy to worked out examples. The results suggest that subjects are quite able to induce a computational procedure for both iterative and recursive functions from examples. Furthermore, prior practice with iterative examples does not seem to facilitate subsequent performance on similar recursive problems, nor does prior practice with recursive examples facilitate performance on iterative problems. The second experiment studied novice subjects' comprehension of iterative and recursive Pascal programs. Comprehension of the iterative program was not improved by prior exposure to the recursive version of the program. Comprehension of the recursive version was improved moderately by prior work with the iterative version.
The performance implications of thread management alternatives for shared-memory multiprocessors
Authors: T. E. Anderson, D. D. Lazowska, H. M. Levy
Venue: Proceedings of the 1989 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (1989)

Threads (&ldquo;lightweight&rdquo; processes) have become a common element of new languages and operating systems. This paper examines the performance implications of several data structure and algorithm alternatives for thread management in shared-memory multiprocessors. Both experimental measurements and analytical model projections are presented. For applications with fine-grained parallelism, small differences in thread management are shown to have significant performance impact, often posing a tradeoff between throughput and latency. Per-processor data structures can be used to improve throughput, and in some circumstances to avoid locking, improving latency as well. The method used by processors to queue for locks is also shown to affect performance significantly. Normal methods of critical resource waiting can substantially degrade performance with moderate numbers of waiting processors. We present an Ethernet-style backoff algorithm that largely eliminates this effect.
On arrangements of Jordan arcs with three intersections per pair
Authors: H. Edelsbrunner, L. J. Guibas, J. Hershberger, J. Pach, R. Pollack
Venue: Proceedings of the fourth annual symposium on Computational geometry (1988)

Motivated by a number of motion-planning questions, we investigate in this paper some general topological and combinatorial properties of the boundary of the union of n regions bounded by Jordan curves in the plane. We show that, under some fairly weak conditions, a simply connected Riemann surface can be constructed that exactly covers this union and whose boundary has combinatorial complexity that is nearly linear, even though the covered region can have quadratic complexity. In the case where our regions are delimited by Jordan arcs in the upper halfplane starting and ending on the x-axis such that any pair of arcs intersect in at most three points, we prove that the total number of subarcs that appear on the boundary of the union is only &THgr;(n&agr;(n)), where &agr;(n) is the extremely slowly growing functional inverse of Ackermann's function.
Line-Drawing Interpretation: Bilateral Symmetry
Authors: V. S. Nalwa
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1989)

Results previously derived by the author are used to investigate the implication of bilateral symmetry in line drawings. It is shown that the line drawing of an orthographically protected surface of revolution exhibits bilateral symmetry about the projection of its axis of revolution irrespective of the viewing direction. Barring one exception, a bilaterally symmetric line drawing is necessarily the orthographic projection of a local surface of revolution whenever its symmetry axis continues to be the projection of a fixed line in space under perturbation of viewpoint; the axis of revolution is the invariant preimage of the symmetry axis. Various line-drawing causes are detailed which facilitate the deduction of invariant preimages of symmetry axes, and consequently of local surfaces of revolution.
From local to global: an analysis of nearest neighbor balancing on hypercube
Authors: J. Hong, X. Tan, M. Chen
Venue: ACM SIGMETRICS Performance Evaluation Review (1988)

This paper will focus on the issue of load balancing on a hypercube network of N processors. We will investigate a typical nearest neighbor balancing strategy - in which workloads among neighboring processors are averaged at discrete time steps. The computation model allows tasks, described by independent random variables, to be generated and terminated at all times. We assume that the random variables at all nodes have equal expected value and their variances are bounded by a constant d2, and we let the difference DIFF between the actual load on each node and the average load on the system describe the deviation of the load on a node from the global average value. The following analytical results are obtained: The expected value of DIFF, denoted by E(DIFF), is 0. The variance of DIFF, denoted by Var(DIFF), is independent of time t, and Var(DIFF)&le; 1.386d2 + 0.231 logN.
The kernel of the Kodaira-Spencer map of the versal¿-constant deformation of an irreducible plane curve singularity with ¿r-action
Authors: Bernd Martin, Gerhard Pfister
Venue: Journal of Symbolic Computation (1989)

An algorithm is described which gives a base of the kernel of the Kodaira-Spencer map of the versal @m-constant deformation of certain plane curve singularities. This is useful for computing the moduli of such singularities.
Ada for closely coupled multiprocessor targets
Authors: A. Cholerton
Venue: Proceedings of the conference on Tri-Ada '89: Ada technology in context: application, development, and deployment (1989)

The techniques for cross-compiling real-time Ada programs for embedded targets are well developed. Generally, these toolsets enable the user to compile and build a program on the host, load it into the target's memories via some form of serial or parallel link, and then run and debug the program under intensive control from the host. This technology has now been extended by SD to provide similar facilities for a class of closely coupled multiprocessor targets comprising homogeneous microprocessors connected by shared memories. The outcome is that a single Ada program can be distributed across the processors of a multiprocessor target. This paper describes the general algorithms by which this is achieved, with emphasis given to certain specific solutions for the SD system. The system employs simple, pragmatic solutions in preference to generalised theoretical ones. The paper describes how an Ada program is distributed across a multiprocessor target, both from a user's view and from an implementation view. It describes how a multiprocessor Ada program can be written, built and debugged. Comparisons are also made with other multiprocessor schemes. The multiprocessor Ada system was developed under a contract placed by MBB on behalf of PANAVIA via the German company TELDIX GmbH. It has been in active use since the middle of 1988 for the development of Ada avionics applications on a special Motorola MC68000 based multiprocessor target developed by TELDIX for the Tornado programme. It is believed to be the first multiprocessor Ada system of its kind in avionics use.
Computer algebra on MIMD machine
Authors: J.-L. Roch, P. Senechaud, F. Sievert-Rich, G. Villard
Venue: ACM SIGSAM Bulletin (1989)

PAC is a computer algebra system, based on MIMD type parallelism. It uses parallelism as a tool for processing problems wich are too complex for a sequential treatment. Basic fundamentals of the system are firstly discussed. Then, different problems are studied, particularly the implementation of infinite-precision arithmetic, the solution of linear systems and of Diophantine equations, the parallelization of Buchberger's algorithm for Gr ouml;bner bases.A prototype of PAC is implemented on the Floating Point System hypercube Tesseract 20 (16 nodes), and different timing results obtained on this machine are given.
Distributed Algorithms for Network Recognition Problems
Authors: K. V. S. Ramarao
Venue: IEEE Transactions on Computers (1989)

The problem of recognizing whether a given network is a tree, ring, star, complete graph, or bipartite graph is considered. Unified algorithms to recognize if the network is any one of the above are presented in each of three classes of algorithms-with centralized, decentralized, and noncentralized initiations. It is shown that the communication and time complexities of the centralized algorithm are linear in e and d, respectively, while those for decentralized algorithm are O(e+n log n) and O(n), respectively (e is the number of edges, n is the number of processors, and d is the diameter of the graph). The complexities for noncentralized algorithms are, respectively O(e+n log k), where k is the level number, and O(n).
The family of Soviet APL systems
Authors: Andrew V. Kondrashev
Venue: ACM SIGAPL APL Quote Quad (1990)

This paper deals with the original implementation of the family of APL systems for widely spread class of mini, micro and personal Soviet computers.
Acquiring knowledge by explaining observed problem solving
Authors: J. D. Martin, M. Redmond
Venue: Issue 108 (April 1989) (1989)

Learning by Understanding Explanations (LBUE) can be an important tool for automatic knowledge acquisition in diagnostic domains. It takes fuller advantage of an expert's knowledge than some more automatic approaches and uses model-based reasoning to reduce brittleness. LBUE specifically integrates the learning of efficiency information as in Explanation Based Generalization (EBG) with further learning of the causal model. Expert protocols are coded into a machine readable form and then input to the LBUE process. The result of learning is that the system becomes capable of solving the same problem in the future and is also able to apply any newly learned causal model information to novel but similar cases.
The flow of control notations pancode and boxcharts
Authors: D. Jonsson
Venue: ACM SIGPLAN Notices (1990)

The textual flow of control notation Pancode and the coresponding graphical notation Boxcharts are defined. These notations embody a new, unified control construct. The definitions given in this paper supersede those in "Pancode and Boxcharts: Structured Programming Revisited" (SIGPLAN Notices, 22, Aug. 1987, 89--98).
Massage-passing controllerr for a shared-memory multiprocessor
Authors: K.e H. Lee, C. H. Lam
Venue: ACM SIGARCH Computer Architecture News (1989)

Although message-passing is a versatile communication paradigm in the multiprocessing arena [AthSe88], a pure message-passing mechanism via special communication channels is inefficient. Shared-memory multiprocessor systems are usually much cheaper and efficient. Conventional approaches tend to implement message-passing on top of shared-memory architectures using a pure software approach. Even with special techniques [FinHe88], the performance of such systems is still worse than simple shared-memory communication systems. In this paper, we shall present a hardware approach and new message-passing mechanisms that the pure software approach does not support. Such an approach is quite cost effective. The resulting system is suitable for studying concurrent software, scientific computations and distributed problem solving.
Invited talk: modular architectures for distributed and databases systems
Authors: A. Z. Spector
Venue: Proceedings of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1989)

This paper describes the importance of modularity in systems and lists a number of reasons why systems will become increasingly modular. It describes two strawmen architecture models for systems and distributed databases in order to illustrate the hierarchical decomposition of complex systems. The paper also relates the systems model to the layering achieved in a few systems familiar to the author.
Communication/computation paradigms for hypercubes
Authors: R. E. Horan, D. A. Poplawski
Venue: Proceedings of the third conference on Hypercube concurrent computers and applications: Architecture, software, computer systems, and general issues - Volume 1 (1988)

Most hypercube node operating systems allow multiple (multiprogrammed) processes per node and buffered, asynchronous communication with routing between arbitrary nodes. The FPS T-Series implements the CSP (communicating sequential process) model of computation on each node and unbuffered, synchronous communication between adjacent nodes. We have implemented on the T-Series several other computation/communication paradigms (for example, single process with routed, unbuffered, synchronous communication) and measured many aspects of communication performance and the computation overheads associated with each. In this paper we compare the performance and overheads of these and various other models of computation/communication and discuss the various models' flexibility and usefulness in typical applications.
On equational theories, unification, and (Un)decidability
Authors: Hans-Jürgen Bürckert, Alexander Herold, Manfred Schmidt-Schauss
Venue: Journal of Symbolic Computation (1989)

We investigate the following classes of equational theories which are important in unification theory: permutative, finite, Noetherian, simple, almost collapse free, collapse free, regular, and @W-free theories. We show some relationships between the particular classes and their connections to the unification hierarchy. Especially, we study conditions, under which minimal and complete sets of unifiers always exist. We have some undecidability results for the membership problem of equational theories to these classes (the 'class problem'): simplicity, almost collapse freeness, and @W-freeness are undecidable properties. Finiteness is known to be also undecidable, and the other investigated properties, permutativity, regularity, and collapse freeness, are known to be trivially decidable. We give an equational theory where every single equation has a minimal set of unifiers, however, for some systems of equations no minimal set of unifiers exists. This example suggests that the definition of a unification problem has to be modified and that the definitions of the unification types have to be adapted accordingly.
The semiconductor market in the European community
Authors: Roger A. Chiarodo, Judee M. Mussehl
Venue: Communications of the ACM (1990)

The authors discuss the impact of three EC rules of origin on printed circuit boards and on the United States semiconductor industry, which has been the largest exporter to Europe.
Evaluation of safety-critical software
Authors: David L. Parnas, A. John van Schouwen, Shu Po Kwan
Venue: Communications of the ACM (1990)

Methods and approaches for testing the reliability and trustworthiness of software remain among the most controversial issues facing this age of high technology. The authors present some of the crucial questions faced by software programmers and eventual users.
Researches in network development of JUNET
Authors: J. Murai, A. Kato
Venue: Proceedings of the ACM workshop on Frontiers in computer communications technology (1987)

JUNET was developed in order to provide a testing environment for studies of computer networking and distributed processing by connecting a large number of computers and by providing actual services for the users. Research interests in development of the network have been focused on resource name managing, Japanese character handling and communication technologies. For the name managements, the hierarchical domain concept is employed to construct a name space for the network, and a mechanism for text message exchange is implemented using the concept. An environment for text message exchange using Japanese characters is achieved as results of general discussions to handle 16-bit Kanji codes in computers. Efficient data transmissions with the high speed modems are achieved by a new UUCP protocol and the dial-up IP link mechanism developed with a tty driver which provides host-to-modem flow control mechanism. As the result of researches described above, JUNET currently connects various types of organizations relating computer science which are 87 organizations with more than 250 computers in number. It connects universities and major research laboratories in Japan, and the protocols currently used are TCP/IP over leased lines as well as dial-up lines, and UUCP over dial-up lines. The services such as electronic mail and network news have been provided since the network was started, and special technologies for Japanese character handling, name servers, and multimedia mail supports have been developed. In this paper, the current status of JUNET and its research results in development of the network are described.
PISCES: an expert system for coal fired power plant monitoring and diagnostics
Authors: Eddie S. Washington, Moonis Ali
Venue: Proceedings of the 1st international conference on Industrial and engineering applications of artificial intelligence and expert systems - Volume 1 (1988)

Economics and safety are two of the primary factors that influence the efficient operation of today's complicated power plants. The use of a computer expert system to assist in automatic plant system surveillance and diagnostics can reduce the operation cost and provide a greater degree of safety and system reliability. In our expert system, called PISCES (Plant Intelligent Supervisory Control System), plant engineers' experience and technical knowledge are represented symbolically and employed in diagnosing problems automatically and in providing assistance to inexperienced engineers, technicians, or operators who perform duties in the absence of an experienced plant engineer. The knowledge base of PISCES was developed using the MHD power plant which employs the Department of Energy's (DOE) coal fired flow facility at the University of Tennessee Space Institute. PISCES is a ruled-based system whose efficiency has been enhanced by the use of several research tools developed at our laboratory. The indexing of rules saves a lot of processing time which other rulebased systems waste in searching for proper rules. The PISCES's control strategy dynamically generates, processes and verifies hypotheses. The diagnostic results are displayed to operators, and explanations are provided on request. This paper describes the mechanism and functionality of the automatic diagnosis performed by PISCES.
Automatic, look-and-feel independent dialog creation for graphical user interfaces
Authors: Brad Vander Zanden, Brad A. Myers
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: Empowering people (1990)

Jade is a new interactive tool that automatically creates graphical input dialogs such as dialog boxes and menus. Application programmers write a textual specification of a dialog's contents. This specification contains absolutely no graphical information and thus is look-and-feel independent. The graphic artist uses a direct manipulation graphical editor to define the rules, graphical objects, interaction techniques, and decorations that will govern the dialog's look-and-feel, and stores the results in a look and feel database. Jade combines the application programmer's specification with the look-and-feel database to automatically generate a graphical dialog. If necessary, the graphic artist can then edit the resulting dialog using a graphical editor and these edits will be remembered by Jade, even if the original textual specification is modified. By eliminating all graphical references from the dialog's content specification, Jade requires only the absolutely minimum specification from the application programmer. This also allows a dialog box or menu's look and feel to be rapidly and effortlessly changed by simply switching look and feel databases. Finally, Jade permits complex inter-field relationships to be specified in a simple manner.
Formalization of the control stack
Authors: J. A. Velazques Iturbide
Venue: ACM SIGPLAN Notices (1989)

The main aim of the article is to show a simple explanation of how variables are accessed in block-structured programming languages. For such a purpose, the run-time devices generically known as control stacks are modelled as an abstract data type.
End-user modifiability in design environments
Authors: Gerhard Fischer, Andreas Girgensohn
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: Empowering people (1990)

Convivial systems encourage users to be actively engaged in generating creative extensions to the artifacts given to them. Convivial systems have the potential to break down the counterproductive barrier between programming and using programs. Knowledge-based design environments are prototypes for convivial systems. These environments support human problem-domain communication, letting users work within their domains of expertise. One of the design rationales behind design environments is to ease the construction and modification of artifacts designed within the environment. But because design environments are intentionally not general purpose programming environments, situations will arise that require modifications to the design environment itself. The rationale and the techniques for these later modifications are discussed in this paper. Our conceptual framework for end-user modifiability is illustrated in the context of JANUS, an environment for architectural design. Evaluating our system building efforts against our objectives shows the subtleties of integrating end-user modifiability in these kinds of systems.