ppxscal/embedding_network huggingface dataset:
Performance transformations for irregular applications
Authors: Michelle Mills Strout
Venue:  (2003)

Irregular computations occur in several important science and engineering applications: molecular dynamics simulations, n-body problems, Finite Element Analysis, etc. The observed performance in such irregular applications is typically cited as 10% or less of the advertised peak performance of current computer architectures. These applications frequently use compact sparse matrix formats that inhibit compile-time transformation opportunities. Sparse matrix formats inhibit the static analysis required by compile-time transformations, because their use introduces non-affine memory references such as A[B[i]]. Such memory references result in memory access patterns that can not be determined at compile-time. Therefore, run-time data and computation reordering transformations are needed to improve data locality and exploit parallelism, both of which are essential for improved program performance on current computer architectures. Run-time reordering transformations are implemented with inspectors and executors. The inspector traverses the memory reference pattern at run-time, generates data and computation reordering functions based on the observed pattern, creates new schedules, and remaps affected data structures accordingly. The executor is a transformed version of the original program that uses the schedules and remapped data structures generated by the inspector. The challenges inherent in using run-time reordering transformations are the need to amortize the overhead of the inspector, and the automatic composition and generation of the inspector/executor code. This dissertation makes three main contributions: the development of a run-time reordering transformation for data locality and parallelism called full sparse tiling; a description of technical and software engineering issues that occur when incorporating run-time reordering transformations such as full sparse tiling into existing software packages; and a framework for composing full sparse tiling and other run-time reordering transformations at compile-time. Our results show that on scientific computing benchmarks, compositions of run-time reordering transformations can result in significant performance improvements in serial and parallel processing environments, and that it is possible to amortize the overhead of the inspector.
Combined Application of Data Transfer and Storage Optimizing Transformations and Subword Parallelism Exploitation for Power Consumption and Execution Time Reduction in VLIW Multimedia Processors
Authors: K. Masselos, F. Catthoor, C. E. Goutis, H. Deman
Venue: Journal of VLSI Signal Processing Systems (2004)

In this paper the important issues in mapping data dominated multimedia applications on Very Long Instruction Word (VLIW) multimedia processors are addressed. The main design quality factors of applications realized on the target architecture platform are presented and their interactions are explored. Power consumption is the major cost factor while performance is the overriding constraint in realizations of multimedia applications on the target architecture platform. A methodology for the reduction of the data transfer and storage related power consumption, which forms an important part of the total power budget of the system, and the execution time of applications realized on VLIW multimedia processors, has been developed. The methodology is based on the application of a number of transformations, mainly oriented towards data transfer and storage optimization, to a high level description of the target application. The main focus of this paper is on the interaction of the proposed code transformations with the exploitation of subword parallelism (for example through the application of special performance improving arithmetic subword instructions present in modern VLIW multimedia processors). Experimental results from real-life data-dominated multimedia applications clearly demonstrate that the application of the proposed transformations is orthogonal to the exploitation of subword parallelism. A second conclusion is that the positive impact of the proposed code transformations on performance is typically even larger than the effect of the subword parallelism exploitation for the complete application. The effect of the subword parallelism exploitation is even enhanced after the application of the proposed code transformations.
Strata-various: multi-layer visualization of dynamics in software system behavior
Authors: Doug Kimelman, Bryan Rosenburg, Tova Roth
Venue: Proceedings of the conference on Visualization '94 (1994)

Current software visualization tools are inadequate for understanding, debugging, and tuning realistically complex applications. These tools often present only static structure, or they present dynamics from only a few of the many layers of a program and its underlying system. This paper introduces "PV", a prototype program visualization system which provides concurrent visual presentation of behavior from all layers, including: the program itself, user-level libraries, the operating system, and the hardware, as this behavior unfolds over time. PV juxtaposes views from different layers in order to facilitate visual correlation, and allows these views to be navigated in a coordinated fashion. This results in an extremely powerful mechanism for exploring application behavior. Experience is presented from actual use of PV in production settings with programmers facing real deadlines and serious performance problems.
Buffer occupancy analysis for a broadband polling-based WLAN
Authors: Ashraf S. Hasan Mahmoud, David D. Falconer, Samy A. Mahmoud
Venue: Network control and engineering for Qos, security and mobility II (2003)

Driven by growing demands for high-bandwidth multimedia services, Wireless Local Area Networks (WLANs) are now being designed with access schemes catering for both synchronous and asynchronous services. A polling-based Medium Access Control (MAC) protocol for broadband indoor WLAN is briefly presented. Analytical evaluation of the embedded queueing model is performed under some assumptions, and the wireless terminal buffer size probability mass function is derived as a function of the cell loss probability, frame length and structure, and the input traffic statistics. The analysis considers a finite buffer size terminal case, and presents statistics of buffer blocking and mean number traffic cells in buffer. The analysis considers renewal input traffic models such as the generalized batched-Bernoulli models where traffic arrivals during interservice times are statistically independent.
A fast solver for the Stokes equations with distributed forces in complex geometries
Authors: George Biros, Lexing Ying, Denis Zorin
Venue: Journal of Computational Physics (2004)

We present a new method for the solution of the Stokes equations. The main features of our method are: (1) it can be applied to arbitrary geometries in a black-box fashion; (2) it is second-order accurate; and (3) it has optimal algorithmic complexity. Our approach, to which we refer as the embedded boundary integral method (EBI), is based on Anita Mayo's work for the Poisson's equation: "The Fast Solution of Poisson's and the Biharmonic Equations on Irregular Regions", SIAM Journal on Numerical Analysis, 21 (1984) 285-299. We embed the domain in a rectangular domain, for which fast solvers are available, and we impose the boundary conditions as interface (jump) conditions on the velocities and tractions. We use an indirect boundary integral formulation for the homogeneous Stokes equations to compute the jumps. The resulting equations are discretized by Nyström's method. The rectangular domain problem is discretized by finite elements for a velocity-pressure formulation with equal order interpolation bilinear elements (Q1-Q1). Stabilization is used to circumvent the inf-sup condition for the pressure space. For the integral equations, fast matrix-vector multiplications are achieved via an N logN algorithm based on a block representation of the discrete integral operator, combined with (kernel independent) singular value decomposition to sparsify low-rank blocks. The regular grid solver is a Krylov method (conjugate residuals) combined with an optimal two-level Schwartz-preconditioner. For the integral equation we use GMRES. We have tested our algorithm on several numerical examples and we have observed optimal convergence rates.
Improving image retrieval effectiveness via multiple queries
Authors: Xiangyu Jin, James C. French
Venue: Proceedings of the 1st ACM international workshop on Multimedia databases (2003)

Conventional approaches to image retrieval are based on the assumption that relevant images are physically near the query image in some feature space. This is the basis of the cluster hypothesis. However, semantically related images are often scattered across several visual clusters. Although traditional Content-based Image Retrieval (CBIR) technologies may utilize the information contained in multiple queries (gotten in one step or through a feedback process), this is only a reformulation of the original query. As a result these strategies only get the images in some neighborhood of the original query as the retrieval result. This severely restricts the system performance. Relevance feedback techniques are generally used to mitigate this problem. In this paper, we present a novel approach to relevance feedback which can return semantically related images in different visual clusters by merging the result sets of multiple queries. Further research topics, such as achieving candidate queries' visual diversity, are also discussed. We also provide experimental results to demonstrate the effectiveness of our approach.
Negotiating early reuse of components: a model-based analysis
Authors: J. A. Sykes
Venue: UML and the unified process (2003)

Unless existing components are considered during formulation of a system specification, the amount of component reuse that is possible may be limited. In order to increase the amount of reuse, it may be necessary to alter the functionality or performance of the system from that originally envisioned. Tension between stakeholders thus exists. Reuse of components also significantly changes the specification activity because it must now deal with component specifications as input models, which is not necessarily the case when reuse is not the goal. These issues are investigated using a modeling framework based on semiotic theory. The nature of modeling abstractions that could support the negotiation between stakeholders is also explored. Two scenarios are examined: one based on the idea of functional abstractions that can be composed and the other one using structural abstractions of the kind available in the UML as the basis of component composition. Even though at this stage, there are no good examples of functional abstractions that can be composed, it is concluded that functional abstractions are the best prospect for supporting collaboration and negotiation.
A Stability Property of T. Chan's Preconditioner
Authors: Xiao-Qing Jin, Yi-Min Wei, Wei XU
Venue: SIAM Journal on Matrix Analysis and Applications (2003)

In this short note, we prove that T. Chan's preconditioner proposed in {TChan} [SIAM J. Sci. Statist. Comput., 9 (1988), pp. 766--771] is stable for matrices that are normal and stable.
Logical concurrency control for large objects in a multidatabase system
Authors: Gopi K. Attaluri
Venue: Proceedings of the 1993 conference of the Centre for Advanced Studies on Collaborative research: distributed computing - Volume 2 (1993)

Non-traditional database management systems (DBMSs) are being increasingly used for application areas such as computer aided design, geographical data and multimedia presentation. In an environment consisting of both traditional and non-traditional DBMSs, application programmers must deal with diversity of the systems. Moreover, a non-traditional DBMS affects the performance of other systems because of its long duration transactions and large, non-uniform data objects. CORDS aims to address these problems and implement a multidatabase system (MDBS) consisting of both traditional and non-traditional DBMSs.This paper deals with concurrency control of large, non-uniform data objects in a MDBS. It proposes a logical concurrency control framework to efficiently handle these objects. With this framework, it is possible to share data objects at a finer granularity than that supported by a local database system. We consider local database systems based on locking and present concurrency control and recovery aspects of the framework.
Synthesizing Test Data for Fraud Detection Systems
Authors: Emilie Lundin Barse, Håkan Kvarnström, Erland Jonsson
Venue: Proceedings of the 19th Annual Computer Security Applications Conference (2003)

This paper reports an experiment aimed at generatingsynthetic test data for fraud detection in an IP based video-on-demand service. The data generation verifies a methodologypreviously developed by the present authors [7] thatensures that important statistical properties of the authenticdata are preserved by using authentic normal data andfraud as a seed for generating synthetic data. This enablesus to create realistic behavior profiles for users and attackers.The data can also be used to train the fraud detectionsystem itself, thus creating the necessary adaptation of thesystem to a specific environment. Here we aim to verify theusability and applicability of the synthetic data, by usingthem to train a fraud detection system. The system is thenexposed to a set of authentic data to measure parameterssuch as detection capability and false alarm rate as well asto a corresponding set of synthetic data, and the results arecompared.
Continuous and discrete Bessel wavelet transforms
Authors: R. S. Pathak, M. M. Dixit
Venue: Journal of Computational and Applied Mathematics (2003)

Using the theory of Hankel convolution, continuous and discrete Bessel wavelet transforms are defined. Certain boundedness results and inversion formula for the continuous Bessel wavelet transform are obtained. Important properties of the discrete Bessel wavelet transform are given.
Inverted matrix: efficient discovery of frequent items in large datasets in the context of interactive mining
Authors: Mohammad El-Hajj, Osmar R. Zaïane
Venue: Proceedings of the ninth ACM SIGKDD international conference on Knowledge discovery and data mining (2003)

Existing association rule mining algorithms suffer from many problems when mining massive transactional datasets. One major problem is the high memory dependency: either the gigantic data structure built is assumed to fit in main memory, or the recursive mining process is too voracious in memory resources. Another major impediment is the repetitive and interactive nature of any knowledge discovery process. To tune parameters, many runs of the same algorithms are necessary leading to the building of these huge data structures time and again. This paper proposes a new disk-based association rule mining algorithm called Inverted Matrix, which achieves its efficiency by applying three new ideas. First, transactional data is converted into a new database layout called Inverted Matrix that prevents multiple scanning of the database during the mining phase, in which finding frequent patterns could be achieved in less than a full scan with random access. Second, for each frequent item, a relatively small independent tree is built summarizing co-occurrences. Finally, a simple and non-recursive mining process reduces the memory requirements as minimum candidacy generation and counting is needed. Experimental studies reveal that our Inverted Matrix approach outperform FP-Tree especially in mining very large transactional databases with a very large number of unique items. Our random access disk-based approach is particularly advantageous in a repetitive and interactive setting.
On resource placements in 3D tori
Authors: Bader F. Al Bdaiwi, Bella Bose
Venue: Journal of Parallel and Distributed Computing (2003)

Perfect distance-d placements in 3D tori is investigated. It is proved that there exists no linear perfect distance-1 placement other than the known ones so far. Perfect distance-d placements in 3D tori, where at least one of the dimensions is 2, are presented. Furthermore, quasi-perfect placements for 3D tori are introduced.
A Crosstalk Aware Interconnect with Variable Cycle Transmission
Authors: Lin Li, N. Vijaykrishnan, Mahmut Kandemir, Mary Jane Irwin
Venue: Proceedings of the conference on Design, automation and test in Europe - Volume 1 (2004)

Crosstalk between wires, caused by increased capacitive coupling, is considered one of the major factors that affect the performance of interconnects such as buses. The data-dependent nature of crosstalk-induced delays necessitates bus cycle time to be designed for the worst case crosstalk. However, this pessimism incurs a significant performance penalty. Consequently, we propose a crosstalk aware inter-connect that uses a faster clock and dynamically controls the number of cycles required for transmission based onthe estimated delay of the data pattern to be transmitted. In order to accomplish this, we designed a crosstalk analyzer circuit that is incorporated into the sender side of the bus and support a variable cycle transmission mechanism. We evaluate the effectiveness of the proposed scheme focusing on the on-chip buses of a microprocessor and by using the SPEC2000 benchmarks. The experimental results show that the proposed approach improves performance by 31.5% as compared to the original pessimistic approach. Furthermore, we employ a coding optimization to enhance the effectiveness of the proposed approach. We also show that the proposed scheme is an area-efficient approach to improving performance as compared to other crosstalk reduction schemes.
Computing with features as formulae
Authors: Mark Johnson
Venue: Computational Linguistics (1994)

This paper extends the approach to feature structures developed in Johnson (1991a), which uses Sch&ouml;nfinkel-Bernays' formulae to express feature structure constraints. These are shown to be a disjunctive generalization of Datalog clauses, as used in database theory. This paper provides a fixed-point characterization of the minimal models of these formulae that serves as the theoretical foundation of a forward-chaining algorithm for determining their satisfiability. This algorithm, which generalizes the standard attribute-value unification algorithm, is also recognizable as a nondeterministic variant of the semi-naive bottom-up algorithm for evaluating Datalog programs, further strengthening the connection between the theory of feature structures and databases.
Military applications of simulation
Authors: Paul K. Davis
Venue: Applied system simulation: methodologies and applications (2003)

This chapter provides a selective overview of simulation activities taking place within the U.S. defense community. It touches upon work with virtual reality, entity-level simulation for analysis, highly distributed simulation in exercises and experimentation, and low-resolution exploratory analysis for higher-level force planning.
Labeling Planar Graphs with Conditions on Girth and Distance Two
Authors: Wei-Fan Wang, Ko-Wei Lih
Venue: SIAM Journal on Discrete Mathematics (2004)

For a planar graph $G$, let $\Delta(G)$, $g(G)$, and $\lambda(G;p,q)$ denote, respectively, its maximum degree, girth, and $L(p,q)$-labeling number. We prove that (1) $\lambda(G;p,q)\le (2q-1)\Delta(G)+4p+4q-4$ if $g(G)\ge 7$; (2) $\lambda(G;p,q)\le (2q-1)\Delta(G)+6p+12q-9$ if $g(G)\ge 6$; (3) $\lambda(G;p,q)\le (2q-1)\Delta(G)+6p+24q-15$ if $g(G)\ge 5$. These bounds have consequences on conjectures by Wegner [Graphs with Given Diameter and a Coloring Problem, preprint, University of Dortmund, Dortmund, Germany, 1977] and Griggs and Yeh [SIAM J. Discrete Math., 5 (1992), pp. 586--595].
A $\sqrt{N}$ Dynamic Load Distribution Algorithm Using Anti-Tasks and Load State Vectors
Authors: Qin Lu, Kwong-Sak Leung, Sau-Ming Lau
Venue: Cluster Computing (2004)

One of the fundamental issues to ensure maximal performance improvement in a cluster computing environment is load distribution, which is commonly achieved by using polling-based load distribution algorithms. Such algorithms suffer from two weaknesses: (1) Load information exchanged during a polling session is confined to the two negotiating nodes only. (2) Such algorithms are not scalable in that growth of the distributed system is accompanied with increasing amount of polling sessions.In this paper, we proposed a LD algorithm which is based on anti-tasks and load state vectors. Anti-tasks travel around the distributed system for pairing up task senders and receivers. As an anti-task travels, timed load information is collected and disseminated over the entire system via the load state vector bundled with the anti-task. Guided by load state vectors, anti-tasks are spontaneously directed towards processing nodes having high transient workload, thus allowing their surplus workload to be relocated soonest possible. No peer-to-peer negotiations between senders and receivers are needed.To reduce the network bandwidth consumption caused by the anti-task algorithm, the number of hosts that an anti-task needs to travel to must be carefully limited. The algorithm achieves this by employing the mathematical notion of Finite Projective Plane (FPP). By employing FPP, the number of nodes that each anti-task has to travel is at most $\sqrt{N}$, where N is the number of nodes in the system, without sacrifying the spread of load information.
Ordered types and a generalized <u>for</u> statement
Authors: Harvey Abramson
Venue: ACM SIGPLAN Notices (1977)

An ordered type is a data structure together with predecessor and successor procedures and a relation defined over pairs of elements of the ordered type. A generalized for statement which uses the procedures connected with an ordered type is introduced. This allows ordered types to be used to control statement iteration in programs.
Design, Implementation and Test of an Email Virus Throttle
Authors: Matthew M. Williamson
Venue: Proceedings of the 19th Annual Computer Security Applications Conference (2003)

This paper presents an approach to preventing the damagecaused by viruses that travel via email. The approachprevents an infected machine spreading the virus further.This directly addresses the two ways that viruses causedamage: less machines spreading the virus will reduce thenumber of machines infected and reduce the traffic generatedby the virus.The approach relies on the observation that normalemailing behaviour is quite different from the behaviour of aspreading virus, with the virus sending messages at a muchhigher rate, to different addresses. To limit propagation arate-limiter or virus throttle is described that does not affectnormal traffic, but quickly slows and stops viral traffic. Thepaper includes an analysis of normal emailing behaviour,and details of the throttle design. In addition an implementationis described and tested with real viruses, showingthat the approach is practical.
Visualizing data: is virtual reality the key?
Authors: Linda M. Stone, Thomas Erickson, Benjamin B. Bederson, Peter Rothman, Raymond Muzzy
Venue: Proceedings of the conference on Visualization '94 (1994)

A visualization goal is to simplify the analysis of large-quantity, numerical data by rendering the data as an image that can be intuitively manipulated. The question this controversial panel addresses is whether or not virtual reality techniques are the cure-all to the dilemma of visualizing increasing amounts of data.This panel determines the usefulness of techniques available today and in the near future that will ease the problem of visualizing complex data. In regards to visualization, the panel members will discuss characteristics of virtual reality systems, data in three-dimensional environments, augmented reality, and virtual reality market opportunities.