ppxscal/embedding_network huggingface dataset:
Site optimal termination protocols for a distributed database under network partitioning
Authors: David Cheung, Tiko Kameda
Venue: ACM SIGOPS Operating Systems Review (1986)

Partition failure causes a major problem for the availability of a distributed database system. No protocol can consistently terminate all parts of a distributed transaction under all possible partitions, since some sites executing subtransactions may not know that other sites have already committed (or aborted) and, therefore, must wait until the failure is repaired. Under a site optimal termination protocol, the expected number of waiting sites is minimized, hence it maximizes the "availability" of a database system in the presence of partition failures. We introduce a new class of partition failures. We introduce a new class of termination protocols, called size-based termination protocols, and identify site optimal termination protocols within this class.
Routing L-shaped channels in nonslicing-structure placement
Authors: H. H. Chen
Venue: Proceedings of the 24th ACM/IEEE Design Automation Conference (1987)

The concept of L-shaped channels was first introduced in RRDO [1] to generate a feasible routing order for nonslicing-structure placement in building-block layout design. This paper presents two approaches for the L-shaped channel-routing problem. In the Manhattan approach, only horizontal and vertical wires are used. The L-shaped channel is divided into two subchannels. The vertical subchannel will be routed first, then the horizontal subchannel will be routed by a special channel router which can handle fixed terminals on 3 sides. Since the routing constraints will change during the boundary movement, several iterations may be needed to complete the routing. In the non-Manhattan approach, 45 &deg; wires are used to preserve the routing constraints when the boundary is moved in the 45 &deg; direction. With all the vertical constraints substituted by 45 &deg; constraints, the L-shaped channel-routing problem can be directly mapped into the straight-type channel-routing problem. Horizontal or vertical extension wires are used to connect terminals on an indented boundary and to separate terminals which are too close to allow the generation of 45 &deg; wires. Experimental results show that both approaches provide good solutions to the L-shaped channel-routing problem.
An extended set of FORTRAN basic linear algebra subprograms
Authors: Jack J. Dongarra, Jeremy Du Croz, Sven Hammarling, Richard J. Hanson
Venue: ACM Transactions on Mathematical Software (TOMS) (1988)

This paper describes an extension to the set of Basic Linear Algebra Subprograms. The extensions are targeted at matrix-vector operations that should provide for efficient and portable implementations of algorithms for high-performance computers.
Beyond two-phase locking
Authors: G. N. Buckley, A. Silberschatz
Venue: Journal of the ACM (JACM) (1985)

Many database systems maintain the consistency of the data by using a locking protocol to restrict access to data items. It has been previously shown that if no information is known about the method of accessing items in the database, then the two-phase protocol is optimal. However, the use of structural information about the database allows development of non-two-phase protocols, called graph protocols, that can potentially increase efficiency. Yannakakis developed a general class of protocols that included many of the graph protocols. Graph protocols either are only usable in certain types of databases or can incur the performance liability of cascading rollback. In this paper, it is demonstrated that if the system has a priori information as to which data items will be locked first by various transactions, a new graph protocol that is outside the previous classes of graph protocols and is applicable to arbitrarily structured databases can be constructed. This new protocol avoids cascading rollback and its accompanying performance degradation, and extends the class of serializable sequences allowed by non-two-phase protocols. This is the first protocol shown to be always as effective as the two-phase protocol, and it can be more effective for certain types of database systems.
Computer support for knowledge workers: A review of laboratory experiments
Authors: Robert L Leitheiser
Venue: ACM SIGMIS Database (1986)

The focus of system design and evaluation has shifted from increasing computer efficiency to improving human/computer effectiveness. The new emphasis is especially critical when the users of the system are not information systems specialists or clerical support personnel, but highly paid knowledge workers. This paper presents a framework for organizing experimental studies in human/computer interaction and suggesting new research opportunities. The framework is applied to a review of 39 experiments in the areas of database management, decision support, text processing, graphics processing, calculation, and operating systems. Studies are assessed for their coverage of experimental variables and organized according to their findings.
A nonlinear Runge-Kutta formula for initial value problems
Authors: D. J. Evans, B. B. Sanugi
Venue: ACM SIGNUM Newsletter (1987)

New non-linear Runge-Kutta methods for solving initial value problems are shown to be obtained by the strategic use of geometric mean (GM) rather than arithmetic mean averaging of the functional values in the standard integration formula.
Cheap hardware support for software debugging and profiling
Authors: T. A. Cargill, B. N. Locanthi
Venue: ACM SIGARCH Computer Architecture News (1987)

We wish to determine the effectiveness of some simple hardware for debugging and profiling compiled programs on a conventional processor. The hardware cost is small -- a counter decremented on each instruction that raises an exception when its value becomes zero. With the counter a debugger can provide data watchpoints and reverse execution: a profiler can measure the total instruction cost of a code segment and sample the program counter accurately. Such a counter has been included on a single-board MC68020 workstation, for which system software is currently being written. We will report our progress at the symposium.
Short-Packet Transfer Performance in Local Area Ring Networks
Authors: Wayne M. Loucks, V. C. Hamacher, Bruno R. Preiss
Venue: IEEE Transactions on Computers (1985)

The performance of various access control protocols for bit-serial local area computer network (LACN) rings is studied. Applications in which mnessage packets are of fixed length and shorter than the total inherent propagation delay around the ring are the focus of attention. Token, slotted, and static and dynamic insertion rings are included in the study. In all cases, the transmitting station is responsible for removing its transmitted packet from the ring. Under this type of removal rule, it is possible for the stations of all types of ring structures to execute their access control algorithms with only a short fixed in-line delay in each station. The insertion rings dynamically switch longer delays (insertion registers) into the ring when they are transmitting a packet. The transmitter-remove rule operates in such a way that hogging of the ring transmission facility by a subset of stations cannot occur. Expressions that approximate average transfer time as a function of utilization are derived for all ring types and are checked by simulation. The expressions are found to be quite accurate at low ring utilization levels, which is the case of most importance for LACN's; but some of them exhibit significant errors at high utilization levels. For the assumed, short-packet environment, it is found that token rings exhibit the slowest transfer times, while dynamic insertion rings are fastest.
An automatic rectilinear partitioning procedure for standard cells
Authors: M. C. Chi
Venue: Proceedings of the 24th ACM/IEEE Design Automation Conference (1987)

This paper describes a new approach to automatically partition and place the standard cells in a rectilinear area on a chip among the pre-placed macro cells (RAM, ROM, PLA etc.) and I/O pads. The macro cells may be placed anywhere on the chip. The topological and physical constraints, and the net list connectivity are accounted for simultaneously. This procedure has been implemented in the AT T Bell Laboratories LTX2 chip layout system.
New algorithms for comparing symbol sequences
Authors: W. J. Hsu
Venue: Proceedings of the 1987 Fall Joint Computer Conference on Exploring technology: today and tomorrow (1987)

A framework is presented for computing substrings and subsequences shared between two symbol sequences. Efficient algorithms are then provided for determining the maximal common substrings.
Comments on "A Massive Memory Machine"
Authors: J R Goodman, H C Young
Venue: IEEE Transactions on Computers (1986)

Garcia-Molina, Lipton, and Valdes [1] introduced a new machine architecture called "massive memory machines" (MMM). The primary application of their proposed architecture was for so-called memory bound computations. In this correspondence we argue: 1) that massive memories will likely become feasible, but will be most effective with much more powerful processors, and 2) that a massive memory on the proposed machine will perform poorly in the same cases that virtual memory performs poorly: whenever there is poor locality of memory reference. Other problems with the architecture are also discussed. These related issues include: 1) the infeasibility of large on-chip dual port memory, 2) the support of multiprocessing on an ESP, 3) the possibility of memory prerequest, 4) the potential of trading program size for execution time, and 5) the time required for clearing the entire memory.
Distributing Hot-Spot Addressing in Large-Scale Multiprocessors
Authors: P.-C. Yew, N.-F. Tzeng, D. H. Lawrie
Venue: IEEE Transactions on Computers (1987)

When a large number of processors try to access a common variable, referred to as hot-spot accesses in [6], not only can the resulting memory contention seriously degrade performance, but it can also cause tree saturation in the interconnection network which blocks both hot and regular requests alike. It is shown in [6] that even if only a small percentage of all requests are to a hot-spot, these requests can cause very serious performances problems, and networks that do the necessary combining of requests are suggested to keep the interconnection network and memory contention from becoming a bottleneck.
The X window system
Authors: Robert W. Scheifler, Jim Gettys
Venue: ACM Transactions on Graphics (TOG) (1986)

An overview of the X Window System is presented, focusing on the system substrate and the low-level facilities provided to build applications and to manage the desktop. The system provides high-performance, high-level, device-independent graphics. A hierarchy of resizable, overlapping windows allows a wide variety of application and user interfaces to be built easily. Network-transparent access to the display provides an important degree of functional separation, without significantly affecting performance, which is crucial to building applications for a distributed environment. To a reasonable extent, desktop management can be custom-tailored to individual environments, without modifying the base system and typically without affecting applications.
Software Projects in an Academic Environment
Authors: David B. Worthman
Venue: IEEE Transactions on Software Engineering (1987)

The "software hut" is a course project that is used in conjunction with a graduate-level course in software engineering. The purpose of this project is to give the students some "real world" experience with the design and implementation of software. This paper describes the author's experience in using such a project and presents some suggestions on how a project should be organized.
An application to support a course in numerical analysis
Authors: Mark Temte
Venue: ACM SIGCSE Bulletin (1987)

An original numerical method is presented which is suitable for use in a course in numerical analysis. It combines numerical differentiation with numerical integration to extend the solution of a particular kind of partial differential equation throughout a rectangular grid. An implementation of the method together with a friendly user interface is available from the author for instructional use.
Comments on "Reliable Loop Topologies for Large Local Computer Networks"
Authors: F. K. Hwang
Venue: IEEE Transactions on Computers (1987)

We comment on the paper by Raghavendra, Gerla, and Avizienis recently published in this TRANSACTIONS [3]. We point out a different routing strategy leading to a skip distance with diameter roughly v3N as compared to the diameter 2vN from the "optimal" skip distance obtained in that paper.
Practical in-place merging
Authors: Bing-Chao Huang, Michael A. Langston
Venue: Communications of the ACM (1988)

We present a novel, yet straightforward linear-time algorithm for merging two sorted lists in a fixed amount of additional space. Constant of proportionality estimates and empirical testing reveal that this procedure is reasonably competitive with merge routines free to squander unbounded additional memory, making it particularly attractive whenever space is a critical resource.
AWB-ADE: an application development environment for interactive, integrated systems
Authors: Carolyn Childs, Filippos I Vokolos
Venue: Proceedings of the second ACM SIGSOFT/SIGPLAN software engineering symposium on Practical software development environments (1987)

The AWB Application Development Environment (AWB-ADE) is a collection of UNIX* based software tools within an architecture that facilitates the development of new interactive, integrated software systems with significant productivity gain. The main characteristic of this environment is that it encourages a high degree of reusability, especially at the architecture and program level, and it provides facilities for the development of software through rapid prototyping. Further, it is an environment with an open architecture and as such it can easily be extended to meet the variety of needs of its diverse user community.
Routing with a scanning window-8Ma unified approach
Authors: D. Kaplan
Venue: Proceedings of the 24th ACM/IEEE Design Automation Conference (1987)

A general approach to routing by a scanning window is presented, and an experimental switch-box router based on this approach is described. This router first grades conductor segments that are candidates to enter the window according to their estimated contributions to routing success, and then uses a quasi-maximal set of segments. A grade function that imitates human intuition is also described.
The Effects of Problem Partitioning, Allocation, and Granularity on the Performance of Multiple-Processor Systems
Authors: Z. Cvetanovic
Venue: IEEE Transactions on Computers (1987)

In this paper we analyze the effects of the problem decomposition, the allocation of subproblems to processors, and the grain size of subproblems on the performance of a multiple- processor shared-memory architecture. Our results indicate that for algorithms where both the computation and the communication overhead can be fully decomposed among N processors, the speedup is a nondecreasing function of the level of granularity for arbitrary interconnection structure and allocation of subproblems to processors. For these algorithms, the speedup is an increasing function of the level of granularity provided that the interconnection bandwidth is greater than unity. If the bandwidth is equal to unity, then the speedup converges to the value equal to the ratio of processing time to communication time. For algorithms where the computation is decomposable but the communication overhead cannot be decomposed, the speedup is a nondecreasing function of the level of granularity for the best case bandwidth only. If the bandwidth is less than N, the speedup reaches its maximum and then decreases approaching zero as the level of granularity grows. For algorithms where the computation consists of parallel and serial sections of code and the communication overhead is fully decomposable, the speedup converges to a value inversely proportional to the fraction of time spent in the serial code even for the best case interconnection bandwidth.
Beyond the chalkboard: computer support for collaboration and problem solving in meetings
Authors: Mark Stefik, Gregg Foster, Daniel G. Bobrow, Kenneth Kahn, Stan Lanning, Lucy Suchman
Venue: Communications of the ACM (1987)

Although individual use of computers is fairly widespread, in meetings we tend to leave them behind. At Xerox PARC, an experimental meeting room called the Colab has been created to study computer support of collaborative problem solving in face-to-face meetings. The long-term goal is to understand how to build computer tools to make meetings more effective.
A knowledge-based approach to computer-aided design of structures
Authors: H. Adeli, K. V. Balasubramanyam
Venue: Proceedings of the 1987 Fall Joint Computer Conference on Exploring technology: today and tomorrow (1987)

A novel approach is presented for development of expert systems for structural design problems. This approach differs from the conventional expert systems in two fundamental respects. First, mathematical optimization is introduced into the design process. Second, computer is used to obtain parts of the knowledge necessary in the expert systems, in addition to heuristics and experiential knowledge obtained from documented materials and human experts. As an example of this approach, a prototype expert system is presented for optimum design of bridge trusses subjected to moving loads, called BTEXPERT. BTEXPERT has been developed by interfacing an interactive optimization program developed in FORTRAN to an expert system shell developed in Pascal. This new generation of expert systems embracing various advanced technologies such as artificial (machine) intelligence, numerical optimization technique, and interactive computer graphics should find enormous practical implications.
A note on Einstein metrics&mdash;a simple application of a symbolic algebra system
Authors: Birger Nielsen, Hendrik Pedersen
Venue: ACM SIGSAM Bulletin (1988)

The Einstein equations consist of ten 2nd order non-linear coupled differential equations for a metric. It is not only hard to solve these equations, but also difficult just to check whether a conjectured metric works. We describe how we verified a conjecture on a generalization of a recent metric of Gegenberg and Das via the REDUCE symbolic computation system.
The weighted region problem
Authors: J. Mitchell, C. Papadimitriou
Venue: Proceedings of the third annual symposium on Computational geometry (1987)

We present an algorithm for determining the shortest path between a source and a destination through a planar subdivision in which each region has an associated weight. Distances are measured according to a weighted Euclidean metric: Each region of the subdivision has associated with it a weight, and the weighted distance between two points in a convex region is the product of the corresponding weight and the Euclidean distance between them. Our algorithm runs in time &Ogr;(n7 L) and requires &Ogr;(n3) space, where n is the number of edges of the subdivision, and L is the precision of the problem instance (including the number of bits in a user-specified tolerance &isin;, which is the percentage the solution is allowed to differ from an optimal solution). The algorithm uses the fact that shortest paths obey Snell's Law of Refraction at region boundaries, a local optimality property of shortest paths that is well-known from the analogous optics model.
Generalized stochastic subdivision
Authors: J. P. Lewis
Venue: ACM Transactions on Graphics (TOG) (1987)

Stochastic techniques have assumed a prominent role in computer graphics because of their success in modeling a variety of complex and natural phenomena. This paper describes the basis for techniques such as stochastic subdivision in the theory of random processes and estimation theory. The popular stochastic subdivision construction is then generalized to provide control of the autocorrelation and spectral properties of the synthesized random functions. The generalized construction is suitable for generating a variety of perceptually distinct high-quality random functions, including those with non-fractal spectra and directional or oscillatory characteristics. It is argued that a spectral modeling approach provides a more powerful and somewhat more intuitive perceptual characterization of random processes than does the fractal model. Synthetic textures and terrains are presented as a means of visually evaluating the generalized subdivision technique.
The LDF 100: a large grain dataflow parallel processor
Authors: Ian Kaplan
Venue: ACM SIGARCH Computer Architecture News (1987)

The LDF 100 is a large grain dataflow parallel processor. The systems is designed to be incrementally expandable from 10 to over 128 processing elements. To avoid memory contention or prohibitive cost, the LDF 100 uses a distributed memory architecture. The LDF 100 also supports parallelism in the processing element. Each processing element consists of two microprocessors. One microprocessor is responsible for collecting data from the dataflow bus and one microprocessor is responsible for application execution.
A model of computation for VLSI with related complexity results
Authors: Bernard Chazelle, Louis Monier
Venue: Journal of the ACM (JACM) (1985)

A new model of computation for VLSI, based on the assumption that time for propagating information is at least linear in the distance, is proposed. While accommodating for basic laws of physics, the model is designed to be general and technology independent. Thus, from a complexity viewpoint, it is especially suited for deriving lower bounds and trade-offs. New results for a number of problems, including fan-in, transitive functions, matrix multiplication, and sorting are presented. As regards upper bounds, it must be noted that, because of communication costs, the model clearly favors regular and pipelined architectures (e.g., systolic arrays).
Concurrent search structure algorithms
Authors: Dennis Shasha, Nathan Goodman
Venue: ACM Transactions on Database Systems (TODS) (1988)

A dictionary is an abstract data type supporting the actions member, insert, and delete. A search structure is a data structure used to implement a dictionary. Examples include B trees, hash structures, and unordered lists. Concurrent algorithms on search structures can achieve more parallelism than standard concurrency control methods would suggest, by exploiting the fact that many different search structure states represent one dictionary state. We present a framework for verifying such algorithms and for inventing new ones. We give several examples, one of which exploits the structure of Banyan family interconnection networks. We also discuss the interaction between concurrency control and recovery as applied to search structures.
Adaptive File Allocation in Star Computer Network
Authors: Clement T. Yu, Man-Keung Siu, K. Lam, C. H. Chen
Venue: IEEE Transactions on Software Engineering (1985)

In this paper, we study the allocation of files in a star network. Unlike previous algorithms which assume that files are independently accessed and independently assigned, the interaction of files during the processing of queries is directly incorporated into our cost model. We present an adaptive algorithm, which is much faster than existing algorithms on file allocation, obtains solutions which are on the average only 0.1 percent away from the optimal solutions, and possesses many desirable properties such as the satisfaction of some necessary and sufficient conditions for file allocation.