ppxscal/embedding_network huggingface dataset:
Real-time temporal and causal reasoning for intelligent control
Authors: Eckart Walther, Vivek V. Badami, James B. Comly, Paul Nielsen, Van-Duc Nguyen
Venue: Proceedings of the 2nd international conference on Industrial and engineering applications of artificial intelligence and expert systems - Volume 1 (1989)

Automation of the control of complex systems has been achieved through the application of computers using such tools as closed-loop control, finite-state machines, etc. However, a number of tasks in the control of such processes must still be performed by human operators, resisting conventional automation efforts. These tasks usually involve unforeseen circumstances, such as defective controller hardware or unusual behavior of the application being controlled. Operators often use experience or heuristic reasoning to cope with these types of process deviations. In this paper, we will describe the theory and design of a generic temporal/causal system called TEMPROS (TEMporal PROgramming System) used to perform intelligent real-time control, capable of assuming many of the responsibilities that are currently exclusively performed by human operators. The system uses temporal propositions as its reasoning mechanism, deviating from current temporal reasoning systems by adding the new state &ldquo;potentially true&rdquo; to the truth value of a proposition. In addition, the system employs a plan hierarchy and a &ldquo;lazy instantiation&rdquo; mechanism to achieve the performance needed to make intelligent decisions in real time. We shall also outline the application of TEMPROS to the domain of growing gallium arsenide crystals using the LEC process.
Critical pair criteria for completion
Authors: Leo Bachmair, Nachum Dershowitz
Venue: Journal of Symbolic Computation (1988)

We formulate the Knuth-Bendix completion method at an abstract level, as an equational inference system, and formalize the notion of critical pair criterion using orderings on equational proofs. We prove the correctness of standard completion and verify all known criteria for completion, including those for which correctness had not been established previously. What distinguishes our approach from others is that our results apply to a large class of completion procedures, not just to a particular version. Proof ordering techniques therefore provide a basis for the design and verification of specific completion procedures (with or without criteria).
On the numerical solution of double-periodic elliptic eigenvalue problems
Authors: E. W. Gekeler
Venue: Computing (1989)

In the present paper, numerical solving of the double-periodic elliptic eigenvalue problems Mu,l:=Du +lu+fu =0 0&le;x<2p,0&le; y<2p3 is considered regarding special symmetry properties. At first, subspaces V with the desired symmetry are constructed then a classical Ritz method is applied for the discretization in V and the resulting finite-dimensional bifurcation problem is solved by an algorithm proposed by Keller and Langford representing a numerical implementation of the Ljapunov-Schmidt procedure. If f(u) is an entire function or a polynomial and V is an algebra then the computed solutions reveal to be stable with respect to perturbations of less symmetry. Some examples demonstrate the efficiency of the procedure. &mdash;Author's Abstract
A real-time support processor for ada tasking
Authors: J. Roos
Venue: ACM SIGARCH Computer Architecture News (1989)

Task synchronization in Ada causes excessive run-time overhead due to the complex semantics of the rendezvous. To demonstrate that the speed can be increased by two orders of magnitude by using special purpose hardware, a single chip VLSI support processor has been designed. By providing predictable and uniformly low overhead for the entire semantics of a rendezvous, the powerful real-time constructs of Ada can be used freely without performance degradation. The key to high performance is the set of primitive operations implemented in hardware. Each operation is complex enough to replace a considerable amount of code was designed to execute with a minimum of communication overhead. Task control blocks are stored on-chip as well as headers for entry, delay and ready queues. All necessary scheduling is integrated in the operations. Delays are handled completely on-chip using an internal real-time clock. A multilevel design strategy, based on silicon compilation, made it possible to run actual Ada programs on a functional emulator of the chip and use the results to verify the detailed design. A high degree of parallelism and pipelining together with an elaborate internal addressing scheme has reduced the number of clock cycles needed to perform each operation. Using 2 &mgr;m CMOS, the processor can run at 20 MHz. A complex rendezvous, including the calling sequence and all necessary scheduling, can be performed in less than 15 &mgr;s.
Using a relational system on Wall Street: the good, the bad, the ugly, and the ideal
Authors: Steve Rozen, Dennis Shasha
Venue: Communications of the ACM (1989)

Developers of a Wall Street financial application were able to exploit a relational DBMS to advantage for some data management tasks (the good). For others, the relational system was not helpful (the bad), or could be pressed into service only by means of major or minor contortions (the ugly). The authors identify database constructs that would have simplified developing the application (the ideal).
A Systematic Method for Division with High Average Bit Skipping
Authors: D. M. Mandelbaum
Venue: IEEE Transactions on Computers (1990)

It is shown that, if a division is described by AQ=C, where A is the divisor, Q is the quotient, and C is the dividend, then the bit variables involved in a set of equations, each of which determines a leading bit of C, gives an approximation for Q that an be used in a SRT division scheme. The results of an exhaustive statistical simulation, using all possible combinations of two pairs of integers 12 b in length, in normalized form, representing A and C are presented to validate the method.
Perceptions of the CIS graduate's workstyle: undergraduate business students versus CIS faculty
Authors: C. H. Mawhinney, E. G. Cale, D. R. Callaghan
Venue: Proceedings of the ACM SIGCPR conference on Management of information systems personnel (1988)

Student interest in computer-related careers has declined dramatically in recent years. One possible explanation for this decline is incorrect perceptions of the workstyle associated with the positions held by CIS graduates. A study was conducted which compared the perceptions held by entering freshmen undergraduate business majors with those of CIS faculty. The study showed that: (1) in general there was less agreement among the faculty than among the students, (particularly pertaining to issues which distinguish entry level programmers from entry level analysts), and (2) there were several issues on which the students' views differed appreciably from those of the faculty (particularly pertaining to salaries and technical aptitude). The results suggest that: (1) faculty need to be cognizant of the broad range of entry level positions available to the CIS graduate, and (2) recruiting efforts need to focus on correcting students' misperceptions of starting salaries and pre-requisite background for entry level positions.
A symptotic analysis of large heterogeneous queueing systems
Authors: S. Shenker, A. Weinrib
Venue: ACM SIGMETRICS Performance Evaluation Review (1988)

As a simple example of a large heterogeneous queueing system, we consider a single queue with many servers with differing service rates. In the limit of infinitely many servers, we identify a queue control policy that minimizes the average system delay. When there are only two possible server speeds, we can analyze the convergence of this policy to optimality. Based on this result, we propose policies for large but finite systems with a general distribution of server speeds.
Transfer between menu systems
Authors: P. W. Foltz, S. E. Davies, P. G. Polson, D. E. Kieras
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (1988)

This paper investigates whether changes in the user/computer dialogue structure will affect the performance of users who are familiar with an earlier version of the product. Quantitative predictions using the Kieras and Polson (1985) production system model were derived to test whether changing the lexical attributes and structure of a popular menu-driven word-processor would permit transfer of existing knowledge of the word-processor to a new version. The results show that changes to the dialogue structure of the menu-system are not detrimental, while changes to the lexical attributes of the menus will hinder user performance.
Resolving circularity in attribute grammars with applications to data flow analysis (preliminary version)
Authors: S. Sagiv, O. Edelstein, N. Francez, M. Rodeh
Venue: Proceedings of the 16th ACM SIGPLAN-SIGACT symposium on Principles of programming languages (1989)

Circular attribute grammars appear in many data flow analysis problems. As one way of making the notion useful, an automatic translation of circular attribute grammars to equivalent non-circular attribute grammars is presented. It is shown that for circular attribute grammars that arise in many data flow analysis problems, the translation does not increase the asymptotic complexity of the semantic equations. Therefore, the translation may be used in conjunction with any evaluator generator to automate the development of efficient data flow analysis algorithms. As a result, the integration of such algorithms with other parts of a compiler becomes easier.
On search decision and the efficiency of polynomial-time algorithms
Authors: M. R. Fellows, M. A. Langston
Venue: Proceedings of the twenty-first annual ACM symposium on Theory of computing (1989)

Recent advances in well-partial-order theory, especially the seminal contributions of Robertson and Seymour, have troubling consequences for those who would equate tractability with polynomial-time decidability. Specifically: many problems are now known to be decidable in low-degree polynomial time, but only by decision algorithms with overwhelmingly astronomical constants of proportionality, the existence of such a polynomial-time decision algorithm alone does not ensure that a corresponding search problem can be solved efficiently, and even if both a decision problem and a corresponding search problem can be shown to be polynomial-time computable, there is no guarantee that correct algorithms can be found or even recognized within any bounded amount of time. In this paper, we present a number of techniques for dealing with these remarkable features of algorithms based on well-partially-ordered sets. Our main results include a general strategy with which such algorithms can be made constructive. With the aid of this method, we demonstrate that low-degree polynomial-time algorithms are now known for almost all of the catalogued applications of RS posets. We also prove that, despite the nonconstructive nature of the well-partial-order theory on which this line of research is based, no RS poset application can settle P @@@@ N P non-constructively by any established method of argument.
Static Analysis-based program evolution support in the common lisp framework
Authors: K. Narayanswamy
Venue: Proceedings of the 10th international conference on Software engineering (1988)

The Common Lisp Framework(CLF) is an object-oriented environment to support the development and maintenance of programs written in the language Common Lisp. A static analysis tool, which is part of CLF, supports program evolution in CLF. Since the effectiveness of our approach stems from the basic design and architecture of CLF, we provide an overview of the relevant features of CLF. The static analysis tool asserts the static properties of program objects definitions into the CLF objectbase. CLF's general mechanism to add rules to the objectbase provides the conceptual basis to respond to changes in the static properties of program objects in several interesting ways &mdash; from programming routine responses to program changes to viewing program alterations idiomatically.
Edge concentration: a method for clustering directed graphs
Authors: F. J. Newbery
Venue: ACM SIGSOFT Software Engineering Notes (1989)

The display of a directed graph is a commonly used visual aid for representing relationships. However, some graphs contain so many edges that their display by traditional graph layout algorithms is virtually impossible because of the overwhelming number of crossings. Graphs representing large software systems and their configurations are particularly prone to this problem. Examples of such graphs include: graphs depicting a system's configuration, call graphs, graphs depicting import and export relationships between modules, and graphs depicting the &ldquo;includes&rdquo; relation among a system's source files. This paper proposes the elimination of some edges by replacing sets of edges that have the same set of source and target nodes by a special node called an edge concentration node. Reducing the number of edges often has the desirable side effect of reducing the number of crossings. An algorithm that determines a reasonable set of edge concentrations of a graph in &Ogr;(n4) operations for each level in the graph is presented where n is the number of nodes in that level. Several examples from the area of software configuration management are shown to demonstrate the effectiveness of using edge concentrations.
A protocol to maintain a minimum spanning tree in a dynamic topology
Authors: C. Cheng, I. Cimet, S. Kumar
Venue: Symposium proceedings on Communications architectures and protocols (1988)

We present a distributed protocol for updating and maintaining a minimum-weight spanning tree (MST) in a network with changing topology. The protocol can respond to multiple link/node failures and recoveries that can occur at arbitrary times. Given that an arbitrary finite number of topological changes occur during a period, the protocol finds the MST corresponding to the latest network, within finite time after the last change. The message complexity of the protocol is O(m|E|+k|V|) when k link recoveries and m link failures occur, where |V| and |E| are the total number of nodes and links, respectively.
Congestion avoidance and control
Authors: V. Jacobson
Venue: Symposium proceedings on Communications architectures and protocols (1988)

In October of '86, the Internet had the first of what became a series of 'congestion collapses'. During this period, the data throughput from LBL to UC Berkeley (sites separated by 400 yards and three IMP hops) dropped from 32 Kbps to 40 bps. Mike Karels1 and I were fascinated by this sudden factor-of-thousand drop in bandwidth and embarked on an investigation of why things had gotten so bad. We wondered, in particular, if the 4.3BSD (Berkeley UNIX) TCP was mis-behaving or if it could be tuned to work better under abysmal network conditions. The answer to both of these questions was &ldquo;yes&rdquo;. Since that time, we have put seven new algorithms into the 4BSD TCP: round-trip-time variance estimation exponential retransmit timer backoff slow-start more aggressive receiver ack policy dynamic window sizing on congestion Karn's clamped retransmit backoff fast retransmit Our measurements and the reports of beta testers suggest that the final product is fairly good at dealing with congested conditions on the Internet. This paper is a brief description of (i) - (v) and the rationale behind them. (vi) is an algorithm recently developed by Phil Karn of Bell Communications Research, described in [KP87]. (viii) is described in a soon-to-be-published RFC. Algorithms (i) - (v) spring from one observation: The flow on a TCP connection (or ISO TP-4 or Xerox NS SPP connection) should obey a 'conservation of packets' principle. And, if this principle were obeyed, congestion collapse would become the exception rather than the rule. Thus congestion control involves finding places that violate conservation and fixing them. By 'conservation of packets' I mean that for a connection 'in equilibrium', i.e., running stably with a full window of data in transit, the packet flow is what a physicist would call 'conservative': A new packet isn't put into the network until an old packet leaves. The physics of flow predicts that systems with this property should be robust in the face of congestion. Observation of the Internet suggests that it was not particularly robust. Why the discrepancy? There are only three ways for packet conservation to fail: The connection doesn't get to equilibrium, or A sender injects a new packet before an old packet has exited, or The equilibrium can't be reached because of resource limits along the path. In the following sections, we treat each of these in turn.
Synthesis of concurrent systems with many similar sequential processes (extended abstract)
Authors: P. C. Attie, E. A. Emerson
Venue: Proceedings of the 16th ACM SIGPLAN-SIGACT symposium on Principles of programming languages (1989)

Methods for synthesizing concurrent programs from Temporal Logic specifications based on the use of a decision procedure for testing temporal satisfiability have been proposed by Emerson Clarke [EC82] and Manna Wolper [MW84]. An important advantage of these synthesis methods is that they obviate the need to manually compose a program and manually construct a proof of its correctness. One only has to formulate a precise problem specification; the synthesis method then mechanically constructs a correct solution. A serious drawback of these methods in practice, however, is that they suffer from the state explosion problem. To synthesize a concurrent system consisting of K sequential processes, each having N states in its local transition diagram, requires construction of the global product-machine having at least NK global states in general. This exponential growth in K makes it infeasible to synthesize systems composed of more than 2 or 3 processes. In this paper, we show how to synthesize concurrent systems consisting of many (i.e., a finite but arbitrarily large number K of) similar sequential processes. Our approach avoids construction of the global product-machine for K processes; instead, it constructs a two process product-machine for a single pair of generic sequential processes. The method is uniform in K, providing a simple template that can be instantiated for each process to yield a solution for any fixed K. The method is also illustrated on synchronization problems from the literature.
APL object transfer in a multi-APL site
Authors: H. F. van Eggelen
Venue: ACM SIGAPL APL Quote Quad (1987)

In order to transfer APL objects, workspaces and files between the different mainframes, minis and micros at the European Commission, two APL object transfer systems have been developed. One such system is based on using tapes and follows the Workspace Interchange Convention. This convention had to be extended since it does not handle generalized arrays and user-defined operators. The other system transmits data direct over the communication line. The STSC's supplied workspaces SERXFER and SERHOST have been used and modified to establish this. Since the Commission has several different APLs on its range of computers, some new approaches had to be developed, which are discussed in this paper.
Symbolic computation of the flow of granular avalanches
Authors: Stuart B. Savage
Venue: Journal of Symbolic Computation (1990)

The two-dimensional flow of a mass of cohesionless granular material downa rough bed is studied by the use of the method of strained coordinates. The work is relevant to the motion of rockfalls, ice avalanches and dense flowing snow avalanches. By appropriate non-dimensionalization, a small parameter @?, which is the ratio of the characteristic length to depth of the pile, appears in the equations of motion. Perturbation expansions for the depth and velocity profiles of the moving mass, and the strained coordinate are introduced. The differential equations for terms of various orders are solved and the resulting divergent series are summed by the use of Shanks transformations and Pade approximants. The analysis is carried out with the symbolic manipulation package REDUCE 3.3 and these results are translated by means of GENTRAN into C-code for numerical evaluation. The analytical form of the solution suggested the existence of similarity solutions for certain initial conditions. The analysis also demonstrated the inadequacies of a finite difference routine; this led to the development of a much improved numerical scheme.
The Cornell commission: on Morris and the worm
Authors: T. Eisenberg, D. Gries, J. Hartmanis, D. Holcomb, M. S. Lynn, T. Santoro
Venue: Communications of the ACM (1989)

After careful examination of the evidence, the Cornell commission publishes its findings in a detailed report that sheds new light and dispels some myths about Robert T. Morris and the Internet worm.
Optimal file distribution for partial match retrieval
Authors: Myoung Ho Kim, Sakti Pramanik
Venue: Proceedings of the 1988 ACM SIGMOD international conference on Management of data (1988)

In this paper we present data distribution methods for parallel processing environment. The primary objective is to process partial match retrieval type queries for parallel devices. The main contribution of this paper is the development of a new approach called FX (Fieldwise eXclusive) distribution for maximizing data access concurrency. An algebraic property of exclusive-or operation, and field transformation techniques are fundamental to this data distribution techniques. We have shown through theorems and corollaries that this FX distribution approach performs better than other methods proposed earlier. We have also shown, by computing probability of optimal distribution and query response time, that FX distribution gives better performance than others over a large class of partial match queries. This approach presents a new basis in which optimal data distribution for more general type of queries can be formulated.
A overview of modular smalltalk
Authors: Allen Wirfs-Brock, Brian Wilkerson
Venue: ACM SIGPLAN Notices (1988)

This paper introduces the programming language Modular Smalltalk, a descendant of the Smalltalk-80 programming language. Modular Smalltalk was designed to support teams of software engineers developing production application programs that can run independently of the environment in which they are developed. We first discuss our motivation for designing Modular Smalltalk. Specifically, we examine the properties of Smalltalk-80 that make it inappropriate for our purposes. We then present an overview of the design of Modular Smalltalk, with an emphasis on how it overcomes these weaknesses.
Unidraw: a framework for building domain-specific
Authors: J. M. Vlissides, M. A. Linton
Venue: Proceedings of the 2nd annual ACM SIGGRAPH symposium on User interface software and technology (1989)

Unidraw is a framework for creating object-oriented graphical editors in domains such as technical and artistic drawing, music composition, and CAD. The Unidraw architecture simplifies the construction of these editors by providing programming abstractions that are common across domains. Unidraw defines four basic abstractions: components encapsulate the appearance and behavior of objects, tools support direct manipulation of components, commands define operations on components, and external representations define the mapping between components and a file or database. Unidraw also supports multiple views, graphical connectivity, and dataflow between components. This paper presents Unidraw and three prototype domain-specific editors we have developed with it: a schematic capture system, a user interface builder, and a drawing editor. Experience indicates a substantial reduction in implementation time and effort compared with existing tools.