ppxscal/embedding_network huggingface dataset:
An adaptive software library for fast Fourier transforms
Authors: Dragan Mirković, Rishad Mahasoom, Lennart Johnsson
Venue: Proceedings of the 14th international conference on Supercomputing (2000)

In this paper we present an adaptive and portable software library for the fast Fourier transform (FFT). The library consists of a number of composable blocks of code called codelets, each computing a part of the transform. The actual FFT algorithm used by the code is determined at run-time by selecting the fastest strategy among all possible strategies, given available codelets, for a given transform size. We also present an efficient automatic method of generating the library modules by using a special-purpose compiler. The code generator is written in C and it generates a library of C codelets. The code generator is shown to be flexible and extensible and the entire library can be generated in a matter of seconds. We have evaluated the library for performance on the IBM-SP2, SG1-2000, HP-Exemplar and Intel Pentium systems. We use the results from these evaluations to build performance models for the FFT library on different platforms. The library is shown to be portable, adaptive and efficient.
On-Line Difference Maximization
Authors: Ming-Yang Kao, Stephen R. Tate
Venue: SIAM Journal on Discrete Mathematics (1999)

In this paper we examine problems motivated by on-line financial problems and stochastic games. In particular, we consider a sequence of entirely arbitrary distinct values arriving in random order, and must devise strategies for selecting low values followed by high values in such a way as to maximize the expected gain in rank from low values to high values.First, we consider a scenario in which only one low value and one high value may be selected. We give an optimal on-line algorithm for this scenario, and analyze it to show that, surprisingly, the expected gain is n-O(1), and so differs from the best possible off-line gain by only a constant additive term (which is, in fact, fairly small---at most 15).In a second scenario, we allow multiple nonoverlapping low/high selections, where the total gain for our algorithm is the sum of the individual pair gains. We also give an optimal on-line algorithm for this problem, where the expected gain is $n^2/8-\Theta(n\log n)$. An analysis shows that the optimal expected off-line gain is $n^2/6+\Theta(1)$, so the performance of our on-line algorithm is within a factor of 3/4 of the best off-line strategy.
Exploiting Signal Unobservability for Efficient Translation to CNF in Formal Verification of Microprocessors
Authors: Miroslav N. Velev
Venue: Proceedings of the conference on Design, automation and test in Europe - Volume 1 (2004)

The paper presents a method for translating Boolean circuits to CNF by identifying trees of ITE operators, where each ITE has fanout count of 1, and representing every such tree with a single set of equivalent CNF clauses without intermediate variables for ITE outputs, except for the tree output. This not only eliminates intermediate variables, but also reduces the number of clauses, compared to conventional translation to CNF, where each ITE is assigned an output variable and is represented with a separate set of clauses. Other gates with fanout count of 1 are similarly merged with their fanout gate to generate a single set of equivalent clauses. This translation to CNF was implemented in a decision procedure for the logic of Equality with Uninterpreted Functions and Memories (EUFM), and was applied to formulas from formal verification of microprocessors. To increase the number of ITE-trees in the Boolean formulas, the decision procedure was optimized to preserve the ITE-tree structure of arguments to equality comparisons. In conventional translation to CNF with the unoptimized decision procedure, the benchmark formulas require up to hundreds of thousands of CNF variables and millions of clauses. The best translation strategy reduced the CNF variables by up to 8×; the clauses by up to 17×; the SATsolver decisions by up to 79×; the SAT-solver conflicts by up to96×; and accelerated the SAT solving by up to 420× .
A case for OO -- Java -- in teaching algorithm analysis
Authors: Sergio Rajsbaum, Elisa Viso
Venue: Proceedings of the 2nd international conference on Principles and practice of programming in Java (2003)

This paper presents an approach to algorithm analysis that benefits from and exploits the OO characteristics of Java and the organization Java gives to build the inheritance trees of the classes and, finally, the use of interfaces, collections, and iterators. After defining the inheritance structure of a collection of algorithms -- for instance, graph exploration algorithms - and the different levels of abstraction, we design both the verification and measures of complexity for the abstract algorithms. We prove as many properties as possible at the abstract levels assuming the implementations of the methods called upon will be correct. We also derive a complexity measure in terms of the complexity measures of the abstract methods. When a concrete algorithm is derived, we reuse the proofs we already have, plus the measures, and simply complete them by proving that the properties assumed for the concrete methods indeed hold and obtaining the exact complexity for the method. We call this inheritance tree a generic algorithm.
Adaptive Prefetching for Multimedia Applications in Embedded Systems
Authors: Hassan Sbeyti, Smail Niar, Lieven Eeckhout
Venue: Proceedings of the conference on Design, automation and test in Europe - Volume 2 (2004)

This paper presents a new and simple prefetching mechanism to improve the memory performance of multimedia applications. This method adapts the memory access mechanism to the access patterns as observed in the application. By doing so, performance is increased,the available resources are better utilized and energy consumption is reduced. Using our prefetch method, we are able to get up to 5.5% IPC improvement, more than 50% cache miss reduction, and up to 4.5% energy reduction. Our mechanism results in better performance for a 2KB data cache than is achievable with an 8KB data cache (without prefetching) for StrongArm SA1110 and Xscale-like processor configurations. This mechanism requires limited hardware resources and generates little additional external bus transfers. This makes this adaptive prefetching well suited for embedded microprocessor systems
Robust Control in &ell;1-Formulation: Model Validation and Perturbation Weight Estimation
Authors: V. F. Sokolov
Venue: Automation and Remote Control (2003)

In robust system analysis and robust controller design, the parameters of the nominal system and admissible perturbation classes are usually assumed to be known. In many cases, these classes are described by constraints on perturbation norms and weight filters. Model validation consists in verifying whether the nominal model and the a priori assumptions on measurement perturbations are consistent. A far more difficult problem is the estimation of norms or weights of perturbations from measurement data. In this paper, model verification and perturbation weight estimation are investigated within the framework the &ell;1-theory of robust control corresponding to the fundamental signal space &ell;&infin;. For any model in the form of a linear stationary discrete system with structured uncertainty, model validation is reduced to verifying whether a system of inequalities generated by measurements holds or not. For a model with unstructured uncertainty and diagonal weighted perturbations, optimization of perturbation weights is reduced a fractional quadratic programming problem. For a model with perturbations of irreducible multipliers of the transfer matrix of the nominal system, optimization of perturbation weights is reduced a linear programming problem.
A Survey on Testing and Reuse
Authors: Richard Torkar, Stefan Mankefors
Venue: Proceedings of the IEEE International Conference on Software-Science, Technology & Engineering (2003)

This survey tries to give an account of what type oftrends exist today in software reuse and testing. The focuswas to try to find out how developers use different toolstoday and what tools are lacking, especially in the field ofreuse and testing. The population came from differenttypes of communities and organizations, to better give usa generalized picture of today's developers. We foundthat a majority of the developers participating in thesurvey did not test reused code and other testingmethodologies were not used to the extent that thescientific community takes for granted. A more automatedapproach to testing in combination with code coverageanalysis and statistical analysis was found to be needed.
Reduced energy decoding of MPEG streams
Authors: Malena Mesarina, Yoshio Turner
Venue: Multimedia Systems (2003)

Long battery life and high performance multimedia decoding are competing design goals for portable appliances. For a target level of QoS, the achievable battery life can be increased by dynamically adjusting the supply voltage throughout execution. In this paper, an efficient offline scheduling algorithm is proposed for preprocessing stored MPEG audio and video streams. It computes the order and voltage settings at which the appliance's CPU decodes the frames, reducing energy consumption without violating timing or buffering constraints. Our experimental results elucidate the trade-off between QoS and energy consumption. They demonstrate that the scheduler reduces CPU energy consumption by 19%, without any sacrifice of quality, and by nearly 50%, with only slightly reduced quality. The results also evaluate how the QoS/energy trade-off is affected by buffering and processor speed.
Live 3D video in soccer stadium
Authors: Takayoshi Koyama, Itaru Kitahara, Yuichi Ohta
Venue: ACM SIGGRAPH 2003 Sketches Applications (2003)

A live 3D video system in a real soccer stadium is presented. Players on the pitch are represented with a simplified 3D model. The model is reconstructed from multiple videos obtained by nine CCD cameras surrounding the pitch. Observers can watch the game from arbitrary viewing position. By using real textures of the players, realistic video presentation is possible. All processes are fully automatic and real time. The system can transmit live 3D video to distant places.
Realizability: a historical essay
Authors: Jaap Van Oosten
Venue: Mathematical Structures in Computer Science (2002)

The purpose of this short paper is to sketch the development of a few basic topics in the history of realizability. The number of topics is quite limited and reflects very much my own personal taste, prejudices and area of competence.
Transforming Complex Loop Nests for Locality
Authors: Qing Yi, Ken Kennedy, Vikram Adve
Venue: The Journal of Supercomputing (2004)

Over the past 20 years, increases in processor speed have dramatically outstripped performance increases for standard memory chips. To bridge this gap, compilers must optimize applications so that data fetched into caches are reused before being displaced. Existing compiler techniques can efficiently optimize simple loop structures such as sequences of perfectly nested loops. However, on more complicated structures, existing techniques are either ineffective or require too much computation time to be practical for a commercial compiler. To optimize complex loop structures both effectively and inexpensively, we present a novel loop transformation, dependence hoisting, for optimizing arbitrarily nested loops, and an efficient framework that applies the new technique to aggressively optimize benchmarks for better locality. Our technique is as inexpensive as the traditional unimodular loop transformation techniques and thus can be incorporated into commercial compilers. In addition, it is highly effective and is able to block several linear algebra kernels containing highly challenging loop structures, in particular, Cholesky, QR, LU factorization without pivoting, and LU with partial pivoting. The automatic blocking of QR and pivoting LU is a notable achievement&mdash;to our knowledge, few previous compiler techniques, including theoretically more general loop transformation frameworks [1, 21, 23, 27, 31], were able to completely automate the blocking of these kernels, and none has produced the same blocking as produced by our technique. These results indicate that with low compilation cost, our technique can in practice match the effectiveness of much more expensive frameworks that are theoretically more powerful.
Algorithms for phylogenetic tree reconstruction based on genome rearrangements
Authors: Pavel Pevzner
Venue:  (2002)

Recent progress in genome-scale sequencing and comparative mapping raises new challenges in studies of genome rearrangements. Although the pairwise genome rearrangement problem is well studied, algorithms for reconstructing the most parsimonious rearrangement scenarios for multiple species are in great demand. The previous approaches to the multiple genome rearrangement problem were largely based on the breakpoint distance rather than on a more biologically accurate rearrangement (reversal) distance. Another shortcoming of the existing software tools is their inability to analyze rearrangements (inversions, translocations, fusions, and fissions) of multichromosomal genomes. This thesis proposes a new multiple genome rearrangement algorithm that is based on the rearrangement (rather than breakpoint) distance and that is applicable to both unichromosomal and multichromosomal genomes. We further apply this algorithm for genome-scale phylogenetic tree reconstruction and deriving ancestral gene orders. In particular, our analysis suggests a new improved rearrangement scenario for a very difficult Campanulaceae cpDNA dataset and putative rearrangement scenarios for the human, cat, cow and mouse genomes. In this thesis, we also offer a new lead for the integration of comparative mapping data in genome rearrangement studies. Finally, we describe the web version of the algorithm, which has recently been made available for phylogenetic tree reconstruction and for the exploration of the rearrangement scenarios.
Formal approach to QoS specification and verification
Authors: J. de Meer, A. Rennoch, J. Burmeister
Venue: Proceedings of the 1993 conference of the Centre for Advanced Studies on Collaborative research: software engineering - Volume 1 (1993)

The Quality of Sercvice (QoS) of advanced communication services and applications needs to be defined precisely and also it is necessary to verify that QoS statements hold. For both purposes some means of QoS languages are required. In this paper we propose extentions for the formal description language LOTOS (ISO 8807) with concepts of time consumption, resource allocation and behaviour probabilities. A new action denotation for synchronization in real environments has been introduced and a formal semantics for the time phases during synchronization is defined. Furthermore, we propose LOTOS for the definition of configurations and measurement scenarios in QoS verification experiments.
Navigating massive data sets via local clustering
Authors: Michael E. Houle
Venue: Proceedings of the ninth ACM SIGKDD international conference on Knowledge discovery and data mining (2003)

This paper introduces a scalable method for feature extraction and navigation of large data sets by means of local clustering, where clusters are modeled as overlapping neighborhoods. Under the model, intra-cluster association and external differentiation are both assessed in terms of a natural confidence measure. Minor clusters can be identified even when they appear in the intersection of larger clusters. Scalability of local clustering derives from recent generic techniques for efficient approximate similarity search. The cluster overlap structure gives rise to a hierarchy that can be navigated and queried by users. Experimental results are provided for two large text databases.
Double-pushout graph transformation revisited
Authors: Annegret Habel, Jürgen Müller, Detlef Plump
Venue: Mathematical Structures in Computer Science (2001)

In this paper we investigate and compare four variants of the double-pushout approach to graph transformation. As well as the traditional approach with arbitrary matching and injective right-hand morphisms, we consider three variations by employing injective matching and&sol;or arbitrary right-hand morphisms in rules. We show that injective matching provides additional expressiveness in two respects: for generating graph languages by grammars without non-terminals and for computing graph functions by convergent graph transformation systems. Then we clarify for each of the three variations whether the well-known commutativity, parallelism and concurrency theorems are still valid and &ndash; where this is not the case &ndash; give modified results. In particular, for the most general approach with injective matching and arbitrary right-hand morphisms, we establish sequential and parallel commutativity by appropriately strengthening sequential and parallel independence.
A plan-based mission control center for autonomous vehicles
Authors: Gary Look, Howard Shrobe
Venue: Proceedings of the 9th international conference on Intelligent user interfaces (2004)

Teams of autonomous vehicles (AVs) carry out missions in a number of fields such as space exploration and search-and-rescue. However, human supervision is still required to monitor the status of the team to ensure that the mission is being carried out as planned. To reduce information overload on these supervisors, we have developed an application, the Mission Control Center (MCC), that aggregates and abstracts status information from AVs using a plan-based view of the mission. Using this model, the MCC presents mission status at the level of goals and plans and directs operator attention to the AVs that require the most attention.
Set-at-a-time access to XML through DOM
Authors: Hai Chen, Frank Wm. Tompa
Venue: Proceedings of the 2003 ACM symposium on Document engineering (2003)

To support the rapid growth of the web and e-commerce, W3C developed DOM as an application programming interface that provides the abstract, logical tree structure of an XML document. In this paper, we propose ordered-set-at-a-time extensions for DOM while maintaining its tightly managed navigational nature. In particular, we define the NodeSequence interface with functions that filter, navigate, and transform sequences of nodes simultaneously. The extended DOM greatly simplifies writing some application code, and it can reduce the communications overhead and response time between a client application and the DOM server to provide applications with more efficient processing. As validation of our proposals, we present application examples that compare the convenience and efficiency of DOM with and without extensions.
Web Agents With A Three-Stage Information Filtering Approach
Authors: Kwang Mong Sim
Venue: Proceedings of the 2003 International Conference on Cyberworlds (2003)

With ever-increasing number of websites, users facethe challenge of locating, as well as filtering, browsing, andmonitoring information of astronomical magnitude. While thereare many extant search engines that assist users in locatingURLs, they often return an overwhelmingly large number ofinformation sources for a query, and the (time-consuming butperhaps interesting) task of browsing websites rests heavily onusers. This article presents detailed designs of web agents thatassist users in browsing and filtering information in websites. Inengineering web browsing agents (WBAs), the contributions ofthis research include: (1) devising a 3-stage information filteringapproach that determines the relevance of web pages bydetecting evidence phrases (EP) constructed from WORDNET,counting the frequencies of EP and considering the nearnessamong keywords; and (2) devising a relevance metric tomeasure the relatedness of evidence phrases. Favorableexperimental results show that WBAs are successful in filteringrelevant information in many instances. Discussions on howdifferent word senses affect the information filtering approachare also given.
Systems requirements for organizational learning
Authors: Jim Q. Chen, Ted E. Lee, Ruidong Zhang, Yue Jeff Zhang
Venue: Communications of the ACM (2003)

To produce organizational memory, knowledge management systems must transform individual knowledge into organizational knowledge, sometimes grudgingly.
On the computation of recursion in relational databases
Authors: Yangjun Chen
Venue: Effective databases for text & document management (2003)

A composite object represented as a directed graph is an important data structure which requires efficient support in CAD/CAM, CASE, office systems, software management, Web databases and document databases. It is cumbersome to handle such an object in relational database systems when it involves recursive relationships. In this chapter, we present a new encoding method to support the efficient computation of recursion. In addition, we devise a linear time algorithm to identify a sequence of reachable trees (w.r.t.) a directed acyclic graph (DAG), which covers all the edges of the graph. Together with the new encoding method, this algorithm enables us to compute recursion w.r.t, a DAG in time O(e), where e represents the number of edges of the DAG. More importantly, this method is especially suitable for a relational environment.
Mouthbrush: drawing and painting by hand and mouth
Authors: Chi-ho Chan, Michael J. Lyons, Nobuji Tetsutani
Venue: Proceedings of the 5th international conference on Multimodal interfaces (2003)

We present a novel multimodal interface which permits users to draw or paint using coordinated gestures of hand and mouth. A headworn camera captures an image of the mouth and the mouth cavity region is extracted by Fisher discriminant analysis of the pixel colour information. A normalized area parameter is read by a drawing or painting program to allow read-time gestural control of pen/brush parameters by mouth gesture while sketching with a digital pen/tablet. A new performance task, the Radius Control Task, is proposed as a means of systematic evaluation of performance of the interface. Data from preliminary experiments show that with some practice users can achieve single pixel radius control with ease. A trial of the system by a professional artist shows that it is ready for use as a novel tool for creative artistic expression.
Optimization of a kinetic laser-plasma interaction code for large parallel systems
Authors: Olivier Coulaud, Michaël Dussere, Pascal Hénon, Erik Lefebvre, Jean Roman
Venue: Parallel Computing (2003)

In this work, we simulate the interaction between intense laser radiation and a fully ionized plasma by solving a Vlasov-Maxwell system using the "Particle-In-Cell" (PIC) method. This method provides a very detailed description of the plasma dynamics, but at the expense of large computer resources.Our SPMD 3D PIC code, CALDER, which is fully relativistic, is based on a spatial domain decomposition. Each processor is assigned one subdomain and is in charge of updating its field values and particle coordinates. This paper presents some optimizations to achieve large simulations, such as communication overlapping, cache-friendly data management, and the use of a parallel sparse PCG solves the Poisson's equation.Finally we present the benefits from these optimizations on the IBM SP3 and the physical results for a large case simulation obtained on the CEA/DIF Teraflops parallel computer.