ppxscal/embedding_network huggingface dataset:
DPL: a data parallel language for the expression and execution of general parallel algorithm
Authors: Robert Gordon Willhoft
Venue: ACM SIGAPL APL Quote Quad (1995)

THE NEED FOR a powerful, easy to use, parallel language continues despite very significant advances in the area of parallel processing. Many parallel languages are simply old sequential languages with parallel constructs added. This research describes the Data Parallel Language (DPL), a parallel language built from its foundations on parallel concepts. DPL bases much of its expression on data parallelism found in APL2 and Fortran90. DPL uses a method based on Petri nets for controlling the execution of groups of statements. Therefore, it allows the user to express parallel algorithms in a natural, array-based method that is independent of the underlying parallel architecture.APL has been recognized as a naturally parallel language because of its ability to express algorithms on array arguments directly. This eliminates the need for a programmer to convert them into sequential loops. Fortran90 has recently adopted similar data parallel concepts into the Fortran language. DPL borrows from APL2 and Fortran90 to define an extensive data parallel function set. Functions in DPL are designed to take arrays as arguments and map the execution onto the underlying parallel machine.Petri nets provide a very elegant model for expressing concurrent and asynchronous operations. DPL uses the semantics of Petri nets to provide a general purpose control structure. DPL frees the programmer from having a fixed set of parallel control constructs, such as are provided in most parallel languages. Rather, it provides a method to express parallel execution based only on the input and output conditions of parts of the program.This work provides the complete syntax and semantics of DPL and then explores its use. The expressiveness of the language is demonstrated by showing how common parallel structures can be implemented. The ease of use is analyzed using a study of existing APL2 code to determine the amount of implicit parallelism in an array language. Some of the issues of compiling DPL are discussed and theoretical speedups are given. The advantages of DPL over other languages, especially APL2 and Fortran90, are outlined.
Logical foundations of object-oriented and frame-based languages
Authors: Michael Kifer, Georg Lausen, James Wu
Venue: Journal of the ACM (JACM) (1995)

We propose a novel formalism, called Frame Logic (abbr., F-logic), that accounts in a clean and declarative fashion for most of the structural aspects of object-oriented and frame-based languages. These features include object identity, complex objects, inheritance, polymorphic types, query methods, encapsulation, and others. In a sense, F-logic stands in the same relationship to the object-oriented paradigm as classical predicate calculus stands to relational programming. F-logic has a model-theoretic semantics and a sound and complete resolution-based proof theory. A small number of fundamental concepts that come from object-oriented programming have direct representation in F-logic; other, secondary aspects of this paradigm are easily modeled as well. The paper also discusses semantic issues pertaining to programming with a deductive object-oriented language based on a subset of F-logic.
FERRARI: A Flexible Software-Based Fault and Error Injection System
Authors: Ghani A. Kanawati, Nasser A. Kanawati, Jacob A. Abraham
Venue: IEEE Transactions on Computers (1995)

A major step toward the development offault-tolerant computer systems is the validation of the dependability properties of these systems. Fault/error injection has been recognized as a powerful approach to validate the fault tolerance mechanisms of a system and to obtain statistics on parameters such as coverages and latencies. This paper describes the methodology and guidelines for the design of flexible software based fault and error injection and presents a tool, FERRARI, that incorporates the techniques. The techniques used to emulate transient errors and permanent faults in software are described in detail. Experimental results are presented for several error detection techniques, and they demonstrate the effectiveness of the software-based error injection tool in evaluating the dependability properties of complex systems.Index Terms¿Fault injection, error injection, real time, coverage, latency.
Serializability with constraints
Authors: Toshihide Ibaraki, Tiko Kameda, Toshimi Minoura
Venue: ACM Transactions on Database Systems (TODS) (1987)

This paper deals with the serializability theory for single-version and multiversion database systems. We first introduce the concept of disjoint-interval topological sort (DITS, for short) of an arc-labeled directed acyclic graph. It is shown that a history is serializable if and only if its transaction IO graph has a DITS. We then define several subclasses of serializable histories, based on the constraints imposed by write-write, write-read, read-write, or read-read conflicts, and investigate inclusion relationships among them. In terms of DITS, we give a sufficient condition for a class of serializable histories to be polynomially recognizable, which is then used to show that a new class of histories, named WRW, can be recognized in polynomial time. We also present NP-completeness results for the problem of testing membership in some other classes. In the second half of this paper, we extend these results to multiversion database systems. The inclusion relationships among multiversion classes defined by constraints, such as write-write and write-read, are investigated. One such class coincides with class DMVSR, introduced by Papadimitriou and Kanellakis, and gives a simple characterization of this class. It is shown that for most constraints, multiversion classes properly contain the corresponding single-version classes. Complexity results for the membership testing are also discussed.
An approximate analysis of waiting time in multi-class M/G/1/./EDF queues
Authors: Ken Chen, Laurent Decreusefond
Venue: ACM SIGMETRICS Performance Evaluation Review (1996)

The Earliest-Deadline-First (EDF) queueing discipline is being more and more widely used for handling time-sensitive applications in computer systems and networks. In this paper, we consider an arbitrary number of traffic classes with class-specific soft-deadline. A soft-deadline is a target waiting-time limit that can be missed. EDF queueing has been proved to minimize the maximum delay overflow related to this limit. We propose a quantitative analysis, through the metric of mean waiting time, on the behavior of EDF queueing. This analysis gives also insight on the correlation between traffic classes with different time-constraints. Technically speaking, we have proven that the mean waiting times for an arbitrary set of N classes of traffic streams with soft deadlines are the unique solution of a system of non-linear equations under the constraint of the Kleinrock's conservation law. We then provide an O (N2) algorithm to get the solution. Simulation suggests that the theoretical approximation we made is quite acceptable.
Determining mental state from EEG signals using parallel implementations of neural networks
Authors: Charles W. Anderson, Saikumar V. Devulapalli, Erik A. Stolz
Venue: Scientific Programming (1995)

EEG analysis has played a key role in the modeling of the brain's cortical dynamics, but relatively little effort has been devoted to developing EEG as a limited means of communication. If several mental states can be reliably distinguished by recognizing patterns in EEG, then a paralyzed person could communicate to a device such as a wheelchair by composing sequences of these mental states. EEG pattern recognition is a difficult problem and hinges on the success of finding representations of the EEG signals in which the patterns can be distinguished. In this article, we report on a study comparing three EEG representations, the unprocessed signals, a reduced-dimensional representation using the Karhunen - Lo&egrave;ve transform, and a frequency-based representation. Classification is performed with a two-layer neural network implemented on a CNAPS server (128 processor, SIMD architecture) by Adaptive Solutions, Inc. Execution time comparisons show over a hundred-fold speed up over a Sun Sparc 10. The best classification accuracy on untrained samples is 73% using the frequency-based representation.
Dynamic resource brokering for multi-user query execution
Authors: Diane L. Davison, Goetz Graefe
Venue: Proceedings of the 1995 ACM SIGMOD international conference on Management of data (1995)

We propose a new framework for resource allocation based on concepts from microeconomics. Specifically, we address the difficult problem of managing resources in a multiple-query environment composed of queries with widely varying resource requirements. The central element of the framework is a resource broker that realizes a profit by "selling" resources to competing operators using a performance-based "currency." The guiding principle for brokering resources is profit maximization. In other words, since the currency is derived from the performance objective, the broker can achieve the best performance by making the scheduling and resource allocation decisions that maximize profit. Moreover, the broker employs dynamic techniques and adapts by changing previous allocation decisions while queries are executing. In a first validation study of the framework, we developed a prototype broker that manages memory and disk bandwidth for a multi-user query workload. The performance objective for the prototype broker is to minimize slowdown with the constraint of fairness. Slowdown measures how much higher the response time is in a multi-user environment than a single-user environment, and fairness measures how even is the degradation in response time among all queries as the system load increases, Our simulation results show the viability of the broker framework and the effectiveness of our query admission and resource allocation policies for multi-user workloads.
SIERRA: an interactive system for ergonomic realization of applications
Authors: Jean Vanderdonckt
Venue: ACM SIGCHI Bulletin (1995)

This short paper discusses some early work on the SIERRA (Syst egrave;me Interactif pour l'ERgonomie de R eacute;alisation d'Applications - An Interactive System for Ergonomic Realization of Applications) tool for managing guidelines. The goal of this tool is to develop a hypermedia system managing guidelines, human-computer principles.
A Note on Varieties of Groupoids Arising from m-Cycle Systems
Authors: Darryn E. Bryant
Venue: Journal of Algebraic Combinatorics: An International Journal (1995)

Decompositions of the complete graph with n vertices Kn into edge disjoint cycles of length m whose union is Kn are commonly called m-cycle systems. Any m-cycle system gives rise to a groupoid defined on the vertex set of Kn via a well known construction. Here, it is shown that the groupoids arising from all m-cycle systems are precisely the finite members of a variety (of groupoids) for m &equals; 3 and 5 only.
Modulo Reduction in Residue Number Systems
Authors: Karl C. Posch, Reinhard Posch
Venue: IEEE Transactions on Parallel and Distributed Systems (1995)

Residue number systems provide a good means for extremely long integer arithmetic. Their carry-free operations make parallel implementations feasible. Some applications involving very long integers, such as public key encryption, rely heavily on fast modulo reductions. This paper shows a new combination of residue number systems with efficient modulo reduction methods. Two methods are compared, and the faster one is scrutinized in detail. Both methods have the same order of complexity, $O(\log n)$, with $n$ denoting the amount of registers involved.Index Terms¿Computer arithmetic, cryptography, distributed systems, hardware algorithms, long integer arithmetic, modulo reduction, parallel algorithms, residue number systems.
Data access for the masses through OLE DB
Authors: José A. Blakeley
Venue: ACM SIGMOD Record (1996)

This paper presents an overview of OLE DB, a set of interfaces being developed at Microsoft whose goal is to enable applications to have uniform access to data stored in DBMS and non-DBMS information containers. Applications will be able to take advantage of the benefits of database technology without having to transfer data from its place of origin to a DBMS. Our approach consists of defining an open, extensible Collection of interfaces that factor and encapsulate orthogonal, reusable portions of DBMS functionality. These interfaces define the boundaries of DBMS components such as record containers, query processors, and transaction coordinators that enable uniform, transactional access to data among such components. The proposed interfaces extend Microsoft's OLE/COM object services framework with database functionality, hence these interfaces are collectively referred to as OLE DB. The OLE DB functional areas include data access and updates (rowsets), query processing, schema information, notifications, transactions, security, and access to remote data. In a sense, OLE DB represents an effort to bring database technology to the masses. This paper presents an overview of the OLE DB approach and its areas of componentization.
Fixed-Parameter Tractability and Completeness I: Basic Results
Authors: Rod G. Downey, Michael R. Fellows
Venue: SIAM Journal on Computing (1995)

For many fixed-parameter problems that are trivially soluable in polynomial-time, such as ($k$-)DOMINATING SET, essentially no better algorithm is presently known than the one which tries all possible solutions. Other problems, such as ($k$-)FEEDBACK VERTEX SET, exhibit fixed-parameter tractability: for each fixed $k$ the problem is soluable in time bounded by a polynomial of degree $c$, where $c$ is a constant independent of $k$. We establish the main results of a completeness program which addresses the apparent fixed-parameter intractability of many parameterized problems. In particular, we define a hierarchy of classes of parameterized problems $FPT \subseteq W[1] \subseteq W[2] \subseteq \cdots \subseteq W[SAT] \subseteq W[P]$ and identify natural complete problems for $W[t]$ for $t \geq 2$. (In other papers we have shown many problems complete for $W[1]$.) DOMINATING SET is shown to be complete for $W[2]$, and thus is not fixed-parameter tractable unless INDEPENDENT SET, CLIQUE, IRREDUNDANT SET and many other natural problems in $W[2]$ are also fixed-parameter tractable. We also give a compendium of currently known hardness results as an appendix.
A framework for network protocol software
Authors: Hermann Hüni, Ralph Johnson, Robert Engel
Venue: ACM SIGPLAN Notices (1995)

Writing software to control networks is important and difficult. It must be efficient, reliable, and flexible. Conduits+ is a framework for network software that has been used to implement the signalling system of a mullti-protocol ATM access switch. An earlier version was used to implement TCP/IP. It reduces the complexity of network software, makes it easier to extend or modify network protocols, and is sufficiently efficient. Conduits+ shows the power of a componentized object-oriented framework and of common object-oriented design patterns.
The Lotus notes storage system
Authors: Kenneth Moore
Venue: Proceedings of the 1995 ACM SIGMOD international conference on Management of data (1995)

Lotus Notes is a commercial product that empowers individuals and organizations to collaborate and share information [1].Notes enables the easy development of applications such as messaging, document management, workflow, and asynchronous conferencing. Notes applications can be deployed globally, across independent organizations, among a heterogeneous network of loosely coupled computers that range in size from small notebooks to large multi-processor systems.The third major release of Lotus Notes occurred in May 1993. Notes is a client-server product, with clients available on Windows, OS/2, Macintosh, SCO UNIX, HP-UX, AIX, and Solaris. The server is available on Windows, OS/2, Windows NT (for Intel processors), NetWare, SCO UNIX, HP-UX, AIX, and Solaris.
Disk-tape joins: synchronizing disk and tape access
Authors: Jussi Myllymaki, Miron Livny
Venue: Proceedings of the 1995 ACM SIGMETRICS joint international conference on Measurement and modeling of computer systems (1995)

Today large amounts of data are stored on tertiary storage media such as magnetic tapes and optical disks. DBMSs typically operate only on magnetic disks since they know how to maneuver disks and how to optimize accesses on them. Tertiary devices present a problem for DBMSs since these devices have dismountable media and have very different operational characteristics compared to magnetic disks. For instance, most tape drives offer very high capacity at low cost but are accessed sequentially, involve lengthy latencies, and deliver lower bandwidth. Typically, the scope of a DBMS's query optimizer does not include tertiary devices, and the DBMS might not even know how to control and operate upon tertiary-resident data. In a three-level hierarchy of storage devices (main memory, disk, tape), the typical solution is to elevate tape-resident data to disk devices, thus bringing such data into the DBMS' control, and then to perform the required operations on disk. This requires additional space on disk and may not give the lowest response time possible. With this challenge in mind, we studied the trade-offs between memory and disk requirements and the execution time of a join with the help of two well-known join methods. The conventional, disk-based Nested Block Join and Hybrid Hash Join were modified to operate directly on tapes. An experimental implementation of the modified algorithms gave us more insight into how the algorithms perform in practice. Our performance analysis shows that a DBMS desiring to operate on tertiary storage will benefit from special algorithms that operate directly on tape-resident data and take into account and exploit the mismatch in disk and tape characteristics.
Data compression on a database system
Authors: Gordon V. Cormack
Venue: Communications of the ACM (1985)

A general-purpose data-compression routine&mdash;implemented on the IMS database system&mdash;makes use of context to achieve better compression than Huffman's method applied character by character. It demonstrates that a wide variety of data can be compressed effectively using a single, fixed compression routine with almost no working storage.
A General Approximation Technique for Constrained Forest Problems
Authors: Michel X. Goemans, David P. Williamson
Venue: SIAM Journal on Computing (1995)

We present a general approximation technique for a large class of graph problems. Our technique mostly applies to problems of covering, at minimum cost, the vertices of a graph with trees, cycles or paths satisfying certain requirements. In particular, many basic combinatorial optimization problems fit in this framework, including the shortest path, minimum-cost spanning tree, minimum-weight perfect matching, traveling salesman and Steiner tree problems. Our technique produces approximation algorithms that run in $O(n^2\log n)$ time and come within a factor of 2 of optimal for most of these problems. For instance, we obtain a 2-approximation algorithm for the minimum-weight perfect matching problem under the triangle inequality. Our running time of $O(n^2\log n)$ time compares favorably with the best strongly polynomial exact algorithms running in $O(n^3)$ time for dense graphs. A similar result is obtained for the 2-matching problem and its variants. We also derive the first approximation algorithms for many NP-complete problems, including the non-fixed point-to-point connection problem, the exact path partitioning problem and complex location-design problems. Moreover, for the prize-collecting traveling salesman or Steiner tree problems, we obtain 2-approximation algorithms, therefore improving the previously best-known performance guarantees of 2.5 and 3, respectively [Math. Programming, 59 (1993), pp. 413--420].
Evaluating FTRE's for Dependability Measures in Fault Tolerant Systems
Authors: Suresh Rai
Venue: IEEE Transactions on Computers (1995)

In order to analyze dependability measures in a fault tolerant system, we generally consider a nonstate space or a state space type model. A fault tree with repeated events (FTRE's) presents an important strategy for the nonstate space model. This paper deals with a conservative assessment to complex fault tree models, henceforth called as CRAFT, to obtain an approximate analysis of the FTRE's. It is a noncutset, direct, bottom-up approach. It uses failure probability or failure rate as input and determines a bound on the probability of occurrence of the $\mbi{TOP}$ event. CRAFT generalizes the concept of a cutting heuristic that obtains the signal probabilities for testability measurement in logic circuits. The method is efficient and solves coherent and noncoherent FTRE's having AND, OR, XOR, and NOT gates. In addition, CRAFT considers $M/N$, priority AND, and two types of functional dependency, namely OR and AND types. Examples such as the $Cm^*$ architecture and a fault-tolerant software based on recovery block concept are used to illustrate the approach. The paper also provides a comparison with approaches such as SHARPE, HARP, and FTC.Index Terms¿Coherent and noncoherent structures, conservative assessment, cutting heuristic, dependability measure, fault tree analysis, fault tolerant system, functional dependency, priority AND, signal probability.
Computing Most Nearly Rank-Reducing Structured Matrix Perturbations
Authors: M. A. Wicks, R. A. DeCarlo
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

The paper investigates the problem of computing structured matrix perturbations that cause, or most nearly cause, some specified system matrix to fail to have full rank. The paper discusses some theoretical issues concerning the existence of solutions to these problems. It suggests a numerical approach to computing solutions that utilizes some ideas on differentiation of singular values. Finally, an algorithm for finding structured most rank-reducing perturbations and structured most nearly rank-reducing perturbations is developed. The paper demonstrates convergence of the algorithm to a rank-reducing perturbation or to a local minimum for a most nearly rank-reducing perturbation. Numerical examples illustrating the technique are included.
Scheduling Tasks with AND/OR Precedence Constraints
Authors: Donald W. Gillies, Jane W, .-S. Liu
Venue: SIAM Journal on Computing (1995)

In traditional precedence-constrained scheduling a task is ready to execute when all its predecessors are complete. We call such a task an AND task. In this paper we allow certain tasks to be ready when just one of their predecessors is complete. These tasks are known as OR tasks. We analyze the complexity of two types of real-time AND/OR task scheduling problems. In the first type of problem, all the predecessors of every OR task must eventually be completed, but in the second type of problem, some OR predecessors may be left unscheduled. We show that most problems involving tasks with individual deadlines are NP-complete, and then present two priority-driven heuristic algorithms to minimize completion time on a multiprocessor. These algorithms provide the same level of worst-case performance as some previous priority-driven algorithms for scheduling AND-only task systems.
A QL Procedure for Computing the Eigenvalues of Complex Symmetric Tridiagonal Matrices
Authors: Jane K. Cullum, Ralph A. Willoughby
Venue: SIAM Journal on Matrix Analysis and Applications (1996)

We present a storage efficient procedure for computing all of the eigenvalues of a complex symmetric tridiagonal matrix. This procedure mimics the implicit $QL$ procedure for computing all of the eigenvalues of a real symmetric tridiagonal matrix, modified by heuristics for monitoring and maintaining numerical stability. Numerical experiments demonstrate the capabilities of this procedure.