ppxscal/embedding_network huggingface dataset:
Design and Evaluation of Smart Disk Architecture for DSS Commercial Workloads
Authors: Gokhan Memik, Alok Choudhary, Mahmut T. Kandemir
Venue: Proceedings of the Proceedings of the 2000 International Conference on Parallel Processing (2000)

The requirements for storage space and computational power of large-scale applications are increasing rapidly. Clusters seem to be the most attractive architecture for such applications, due to their low costs and high scalability. On the other hand, smart disk systems; with their large storage, capacities and growing computational power are becoming increasingly popular. In this work, we compare the performance of these architectures with a single host-based system using representative queries from the Decision Support System (DSS) databases. We show how to implement individual database operations in the smart disk system and show how to optimize the execution of the whole query by bundling frequently occurring operations together and executing the bundle in a single invocation. Besides decreasing the overall execution time, operation bundling also offers an easy-to-program and easy-to-use interface to access the data on smart disks. We also present a protocol for minimizing the communication time in the smart disk based system. To measure the response times, we have developed the DBsim, an accurate simulator, which can simulate the database operations for the single host-based, cluster-based and smart disk, based systems. Using this simulator, we illustrate that the smart disk architecture offers substantial benefits in terms of overall query execution times of the TPC-D benchmark suite. In particular, the average response time of the smart disk architecture for the representative queries from the TPC-D benchmark in our base configuration is 71% smaller than the response time on the single host-based system and 4: 2% smaller than the response time on the fastest cluster architecture. We also demonstrate the effectiveness of the operation bundling.
Lexical Categorical Disambiguation using a Multi-Agent Systems Architecture
Authors: J. da Silva, V. Strube de Lima
Venue: Proceedings of the 3rd International Conference on Multi Agent Systems (1998)

In this work we present a distributed architecture model for lexical categorical disambiguation based on Multi-Agent Systems. This proposal aims to minimize some shortcomings from sequential approaches to natural language processing systems, through cooperation among intelligent and distributed modules. We have proposed a model for a linguistic society of agents which includes linguistic knowledge as well as a set of procedures to manipulate it, and mechanisms for social reasoning. The disambiguation is solved by a subsociety of acquaintance agents that use a communication protocol based on cooperative learning in order to reach a common goal.
Quality Mesh Generation in Three Dimensions
Authors: Scott A. Mitchell, Stephen A. Vavasis
Venue:  (1992)

We show how to triangulate a three dimensional polyhedral region with holes. Our triangulation is optimal in the following two senses. First, our triangulation achieves the best possible aspect ratio up to a constant. Second, for any other triangulation of the same region into m triangles with bounded aspect ratio, our triangulation has size n=O(m). Such a triangulation is desired as an initial mesh for a finite element mesh refinement algorithm. Previous three dimensional triangulation schemes either worked only on a restricted class of input, or did not guarantee well shaped tetrahedra, or were not able to bound the output size. We build on some of the ideas presented in previous work by Bern, Eppstein, and Gilbert, who have shown how to triangulate a two dimensional polyhedral region with holes, with similar quality and optimality bounds.
Maintaining the confidentiality of interoperable databases with a multilevel federated security system
Authors: Marta Oliva, Fèlix Saltor
Venue: Proceedings of the fifteenth annual working conference on Database and application security (2001)

When several databases with multilevel security policies are federated to form a tightly coupled federated database management system, heterogeneities such as different accreditation ranges must be overcome. This paper describes an extended methodology to integrate policies that use different lattices as accreditation ranges. A semi-automatic process obtains the federated accreditation range and needed translation functions among accreditation ranges in order to be validated by the security administrator.
Spread of excitation in 3-D models of the anisotropic cardiac tissue. Effects of ventricular geometry and fiber structure on the potential distribution
Authors: Piero Colli Franzone, Luciano Guerri, Micol Pennacchio, Bruno Taccardi
Venue:  (1997)

In this paper we investigate how the potential distribution, in a simplified model of the left ventricle, is affected by several factors such as: fiber structure and obliqueness, curvature of the wall, presence or absence of extracardiac conducting media. The spread of excitation in the myocardial tissue, represented by an anisotropic bidomain, is treated by means of the eikonal approach that yields the space and time dependent transmembrane potential $v$ during the depolarization phase. The extracellular potential $u$ is obtained as the solution of a linear elliptic equation with the source term related to $v$. The introduction of a split form of the cardiac sources and the associated extracellular potential distributions provides a useful tool to gain a better insight into some features of the potential field in terms of the underlying cardiac sources. The split form of the electrical sources may also provide a basis for an improved theory of the electrocardiogram. EMAIL:: ian@microian.ian.pv.cnr.it
Analysis of approximate algorithms for constrained and unconstrained edge-coloring of bipartite graphs
Authors: R. Jain, J. Werth
Venue:  (1995)

The problem of edge-coloring a bipartite graph is to color the edges so that adjacent edges receive different colors. An optimal algorithm uses the minimum number of colors to color the edges. We consider several approximation algorithms for edge-coloring bipartite graphs and show tight bounds on the number of colors they use in the worst case. We also briefly consider the constrained edge-coloring problem where each color may be used to color at most $k$ edges, and obtain bounds on the number of colors used by the approximation algorithms in the worst case.
Foundations of the Bandera abstraction tools
Authors: John Hatcliff, Matthew B. Dwyer, Corina S. Păsăreanu, Robby
Venue: The essence of computation: complexity, analysis, transformation (2002)

Current research is demonstrating that model-checking and other forms of automated finite-state verification can be effective for checking properties of software systems. Due to the exponential costs associated with model-checking, multiple forms of abstraction are often necessary to obtain system models that are tractable for automated checking.The Bandera Tool Set provides multiple forms of automated support for compiling concurrent Java software systems to models that can be supplied to several different model-checking tools. In this paper, we describe the foundations of Bandera's data abstraction mechanism which is used to reduce the cardinality (and the program's state-space) of data domains in software to be model-checked. From a technical standpoint, the form of data abstraction used in Bandera is simple, and it is based on classical presentations of abstract interpretation. We describe the mechanisms that Bandera provides for declaring abstractions, for attaching abstractions to programs, and for generating abstracted programs and properties. The contributions of this work are the design and implementation of various forms of tool support required for effective application of data abstraction to software components written in a programming language like Java which has a rich set of linguistic features.
Combining Multilayer Networks to Combine Learning
Authors: Eric Bax
Venue:  (1997)

This paper explores methods to combine networks, implementations of network combination on multicomputers, and applications of network combination. We divide the network combination process into two steps. First, a matching algorithm rearranges the networks so that corresponding weights in the networks being combined play corresponding roles in the networks'' functions. Then a proportioning algorithm chooses a convex combination of the matched networks. The combination network is a weight-by-weight convex combination of the matched networks. This paper begins by examining combinations of pairs of networks. Matching and proportioning algorithms are developed, analyzed, implemented, and tested. Next, algorithms are developed to combine several networks. Then the combination process is poked and prodded to explore its nature, its utility, and its limits.
A Process Algebra Based Verification of a Production System
Authors: J. J. T. Kleijn, M. A. Reniers, J. E. Rooda
Venue: Proceedings of the Second IEEE International Conference on Formal Engineering Methods (1998)

Studying industrial systems by simulation enables the designer to study the dynamic behaviour and to determine some characteristics of the system. Unfortunately, simulation also has some disadvantages. These can be overcome by using formal methods. Formal methods allow a thorough analysis of the possible behaviours of a system, parameterised system analysis and a modular approach to the analysis of systems.We present a case study in which a model of an industrial system is studied in a formal way. For this purpose, the model is first specified and simulated using the CSP-based executable specification language $\chi$. The model is translated into a model in the process algebra \ACPtau. This enables us to give a correctness proof of the parameterised model andto study the model in isolation.
State of the Art in User Interface Software Tools
Authors: Brad A. Myers
Venue:  (1992)

User Interface Software is inherently difficult to design and implement. This paper discusses some important reasons why user interface software is more difficult than other types of software, and then surveys the approaches that have been taken to address this problem. Many kinds of tools have been designed to help create user interface software, and these can be classified by the styles of interfaces they create, and the techniques used by the user interface designer to create the software. This paper discusses this taxonomy and a number of tools, both research and commercial, in each category. Finally, current research directions and open issues in the field are discussed.
A Data Model for Object-Oriented Databases
Authors: Manojit Sarkar, Steven P. Reiss
Venue:  (1992)

We present an object-oriented data model. The data model represents all entities as objects. The system uses internally generated object identifiers for giving objects their unique identity. An object also has a state and a behavior. Each object belongs to a class. The class defines the structure of the object''s state and its behavior. Classes are organized in an inheritance hierarchy. An object of a class T can be used where an object of T''s superclass is expected. Inheritance polymorphism is provided through late binding of methods based on actual classes of objects. The data model eliminates the objects-versus-values dichotomy by representing all entities as objects. This is achieved at no loss of modeling power or performance. The data model provides for exclusive access of objects by other objects.
A Model for Deferred View Maintenance
Authors: Reda Alhajj, Ashraf Elnagar
Venue: Proceedings of the 1999 International Symposium on Database Engineering & Applications (1999)

We present a model for deferred maintenance of object-oriented views. Queries that define views are implemented as methods that are invoked to compute corresponding views. Deferred update reflects to a view only related modifications introduced into the database while that view was inactive. A view is updated by considering modifications performed within all classes along the inheritance and class-composition subhierarchies rooted at every class used in deriving that view. To each class, we add a modification list to keep one modification tuple per view dependent on that class. Such tuple acts as a reference point that marks the start of the next update to the corresponding view.
Modeling Communication Delay on the iPSC/2 AND iPSC/860 Hypercubes
Authors: C. L. McCreary, M. E. McArdle
Venue:  (1991)

Performance information is essential to the design of efficient parallel programs. Whether the programmer has total control over determining the parallel execution of processes or whether some automatic means are used to parallelize serial or partially parallel code, the cost of the overhead due to parallelization must be known. This is especially important in systems where the costs of such mechanisms are high. In distributed memory systems, message passing is the primary means of communication between parallel processes, and message passing tends to be quite expensive. Users of such systems wrestle with a variety of questions related to performance issues. How is the data to be distributed among processors? What grain size (amount of code executed serially on a processor) is required for efficient processing? How should the processes be assigned to the system nodes? Approximate answers to these questions can be given only if the performance characteristics of the system are known. This paper presents the beginning of a practical performance model for two distributed memory multiprocessor systems, the Intel iPSC/2 and iPSC/860 hypercubes. Performance measurements of communication costs on the range of message passing options of the hypercubes have resulted in several formulas which are useful in modeling communication costs. This work extends that of others in several ways. Each node of the hypercube has its own clock whose time is measured independently of the other clocks. Previous timings were made from only one node to avoid the problem of unsynchronized clocks. We have developed a clock adjustment technique to set clock times to a common value and through this adjustment have been able to time messages that can be sent only one way, such as a broadcast. Other performance modeling of which we are aware concentrated only on node to node communication. We extend communication measurements to situations where m nodes are simultaneously sending information to n nodes.
Monads and Comonads in Intensional Semantics
Authors: Stephen Brookes, Kathryn V Stone
Venue:  (1993)

Kleisli categories over monads have been used in denotational semantics to describe functional languages using various notions of computations as values. Kleisli categories over comonads have also been used to describe intensional semantics rather than extensional. This paper explores the possibilities of combining monads and comonads to obtain an intensional semantics using computations as values. We give three alternative ways to combine the two and explore which apply to known monads and comonads of interest. We will also look at various intensional semantics for an example programming language that uses monads for computations and compare them to the original extensional semantics.
On the Use of Weibull Fault Processes in Modeling Fault Tolerant Systems
Authors: Robert Geist, Mark Smotherman, Kishor Trivedi, B J Dugan
Venue:  (1985)

In this paper we investigate the use of the Weibull distribution in modeling times to failure. In particular, we investigate the computation of instantaneous coverage probabilities from a general fault/error-handling model in which the near-coincident fault process is Weibull. We develop a fast, provably conservative approximation technique for the computation of coverage probabilities. We also provide tight bounds on the error in the approximation. The technique developed in this paper is being implemented in the HARP (Hybrid Automated Reliability Predictor) package.
Automatic Simulation to Predict Software Architecture Reliability
Authors: J. Jenny Li, Josephine Micallef, Joseph R. Horgan
Venue: Proceedings of the Eighth International Symposium on Software Reliability Engineering (1997)

One of the goals of software architecture research is to analyze the reliability of a software system early in the development lifecycle. This allows the system designers to predict reliability and evaluate alternative designs. This paper presents a methodology and accompanying toolset, Workflow-to-SDL-Direct-Simulation (W2S), for generating a simulator from a semi-formal architecture description. This simulator allows the analysis of the system's reliability based on the simulated behavior and performance. There are three steps in the W2S methodology: (1) translation of the description to a Communicating Extended Finite State Machine (CEFSM) model; (2) generation of a simulator from the CEFSM model and a model of the system environment; and (3) execution of the simulator on top of an underlying CEFSM engine. The W2S methodology was applied to a Bellcore tele communication control system, using a set of tools that we developed. Several sets of experiments were carried out. The result shows that the information generated by the simulator can be used to predict the reliability of a system solely based on its architectural description. This prediction allows designers to select more reliable architectures.
Constructive Automata Theory Implemented with the Nuprl Proof Development System
Authors: Christoph Kreitz
Venue:  (1986)

The Nuprl proof development system was designed for the computer-assisted problem solving in mathematics and programming. In particular it can be used for the development of mathematical proofs and of programs which are guaranteed to meet their specifications. The implementation of the theory of finite automata gave lots of insights into its strengths and weaknesses and shows that Nuprl is indeed powerful enough now to obtain nontrivial results within reasonable amounts of time. Its success shall encourage people to actually use the system and build theories within it. This report describes the techniques and the user-defined extensions to the Nuprl object language which were necessary to formulate and prove theorems from the theory of finite automata. It also describes the experiences which came from actually working with the current Nuprl system and gave some useful insights into its strenghts and weaknesses. A complete Nuprl-proof of the pumping lemma and its computational evaluation are presented and an outline for future development is given.
Abstract machines modelling network control systems
Authors: K. Hopper, H. J. Kugler, C. Unger
Venue: ACM SIGOPS Operating Systems Review (1979)

A major problem in designing computer systems is to match the needs of all types of computer users with the real resources available. The concept of an abstract machine working for the user is introduced to overcome this problem. The applicability of this concept in a wide variety of practical environments leads to the development of a proposed standard architecture for network control systems.
State space reduction using partial tau-confluence
Authors: Jan F Groote, Jaco C. Pol
Venue:  (2000)

We present an efficient algorithm to determine the maximal class of confluent $\tau$-transitions in a labelled transition system. Confluent $\tau$-transitions are inert with respect to branching bisimulation. This allows to use $\tau$-priorisation, which means that in a state with a confluent outgoing $\tau$-transition all other transitions can be removed, maintaining branching bisimulation. In combination with the removal of $\tau$-loops, and the compression of $\tau$-sequences this yields an efficient algorithm to reduce the size of large state spaces.
ACE: A Fast Multiscale Eigenvectors Computation for Drawing Huge Graphs
Authors: Yehuda Koren, Liran Carmel, David Harel
Venue: Proceedings of the IEEE Symposium on Information Visualization (InfoVis'02) (2002)

We present an extremely fast graph drawing algorithm for very large graphs, which we term ACE (for Algebraic multigrid Computation of Eigenvectors). ACE exhibits improvement of something like two orders of magnitude over the fastest algorithms we are aware of; it draws graphs of millions of nodes in less than a minute. ACE finds optimal drawing by minimizing a quadratic energy function. The minimization problem is expressed as a generalized eigenvalue problem, which is rapidly solved using novel algebraic multigrid technique. The samegeneralized eigenvalue problem seems to come up also in other fields, hence ACE appears to be applicable outside of graph drawing too.
An Implementation of Mermera: A Shared Memory System that Mixes Coherence with Non-coherence
Authors: Abdelsalam Heddaya, Himanshu Sinha
Venue:  (1993)

Abstract Coherent shared memory is a convenient, but inefficient, method of inter-process communication for parallel programs. By contrast, message passing can be less convenient, but more efficient. To get the benefits of both models, several non-coherent memory behaviors have recently been proposed in the literature. We present an implementation of Mermera, a shared memory system that supports both coherent and non-coherent behaviors in a manner that enables programmers to mix multiple behaviors in the same program~\cite{HeddayaS93}. A programmer can debug a Mermera program using coherent memory, and then improve its performance by selectively reducing the level of coherence in the parts that are critical to performance. Mermera permits a trade-off of coherence for performance. We analyze this trade-off through measurements of our implementation, and by an example that illustrates the style of programming needed to exploit non-coherence. We find that, even on a small network of workstations, the performance advantage of non-coherence is compelling. Raw non-coherent memory operations perform 20-40~times better than non-coherent memory operations. An example aplication program is shown to run 5-11~times faster when permitted to exploit non-coherence. We conclude by commenting on our use of the Isis Toolkit of multicast protocols in implementing Mermera.
Task Parallel Implementation of the Bowyer-Watson Algorithm
Authors: Nikos Chrisochoides, Florian Sukup
Venue:  (1996)

In this paper we present a parallel implementation of the Bowyer-Watson (BW) algorithm using the task-parallel programming model. The BW algorithm constitutes an ideal mesh refinement strategy for implementing a large class of unstructured mesh generation techniques on both sequential and parallel computers, by preventing the need for global mesh refinement. Its implementation on distributed memory multicomputers using the traditional data-parallel model has been proven very inefficient due to excessive synchronization needed among processors.
Latent concepts and the number orthogonal factors in latent semantic analysis
Authors: Georges Dupret
Venue: Proceedings of the 26th annual international ACM SIGIR conference on Research and development in informaion retrieval (2003)

We seek insight into Latent Semantic Indexing by establishing a method to identify the optimal number of factors in the reduced matrix for representing a keyword. This method is demonstrated empirically by duplicating all documents containing a term t, and inserting new documents in the database that replace t with t'. By examining the number of times term t is identified for a search on term t' (precision) using differing ranges of dimensions, we find that lower ranked dimensions identify related terms and higher-ranked dimensions discriminate between the synonyms.