ppxscal/embedding_network huggingface dataset:
New challanges in dynamic load balancing
Authors: Karen D. Devine, Erik G. Boman, Robert T. Heaphy, Bruce A. Hendrickson, James D. Teresco, Jamal Faik, Joseph E. Flaherty, Luis G. Gervasio
Venue: Applied Numerical Mathematics (2005)

Data partitioning and load balancing are important components of parallel computations. Many different partitioning strategies have been developed, with great effectiveness in parallel applications. But the load-balancing problem is not yet solved completely; new applications and architectures require new partitioning features. Existing algorithms must be enhanced to support more complex applications. New models are needed for non-square, non-symmetric, and highly connected systems arising from applications in biology, circuits, and materials simulations. Increased use of heterogeneous computing architectures requires partitioners that account for non-uniform computing, network, and memory resources. And, for greatest impact, these new capabilities must be delivered in toolkits that are robust, easy-to-use, and applicable to a wide range of applications. In this paper, we discuss our approaches to addressing these issues within the Zoltan Parallel Data Services toolkit.
A Convolution-Thresholding Approximation of Generalized Curvature Flows
Authors: Richards Grzhibovskis, Alexei Heintz
Venue: SIAM Journal on Numerical Analysis (2004)

We construct a convolution-thresholding approximation scheme for the geometric surface evolution in the case when the velocity of the surface at each point is a given function of the mean curvature. Conditions for the monotonicity of the scheme are found and the convergence of the approximations to the corresponding viscosity solution is proved. We also discuss some aspects of the numerical implementation of such schemes and present several numerical results.
Optimal Asynchronous Garbage Collection for RDT Checkpointing Protocols
Authors: Rodrigo Schmidt, Islene C. Garcia, Fernando Pedone, Luiz E. Buzato
Venue: Proceedings of the 25th IEEE International Conference on Distributed Computing Systems (2005)

Communication-induced checkpointing protocols that ensure rollback-dependency trackability (RDT) guarantee important properties to the recovery system without explicit coordination. However, to the best of our knowledge, there was no garbage collection algorithm for them which did not use some type of process synchronization, like time assumptions or reliable control message exchanges. This paper addresses the problem of garbage collection for RDT checkpointing protocols and presents an optimal solution for the case where coordination is done only by means of timestamps piggybacked in application messages. Our algorithm uses the same timestamps as off-the-shelf RDT protocols and ensures the tight upper bound on the number of uncollected checkpoints for each process during all the system execution.
A variational discretization concept in control constrained optimization: the linear-quadratic case
Authors: M. Hinze
Venue: Computational Optimization and Applications (2005)

A new discretization concept for optimal control problems with control constraints is introduced which utilizes for the discretization of the control variable the relation between adjoint state and control. Its key feature is not to discretize the space of admissible controls but to implicitly utilize the first order optimality conditions and the discretization of the state and adjoint equations for the discretization of the control. For discrete controls obtained in this way an optimal error estimate is proved. The application to control of elliptic equations is discussed. Finally it is shown that the new concept is numerically implementable with only slight increase in program management. A numerical test confirms the theoretical investigations.
Natural Deduction for First-Order Hybrid Logic
Authors: Torben Braüner
Venue: Journal of Logic, Language and Information (2005)

This is a companion paper to Braüner (2004b, Journal of Logic and Computation 14, 329--353) where a natural deduction system for propositional hybrid logic is given. In the present paper we generalize the system to the first-order case. Our natural deduction system for first-order hybrid logic can be extended with additional inference rules corresponding to conditions on the accessibility relations and the quantifier domains expressed by so-called geometric theories. We prove soundness and completeness and we prove a normalisation theorem. Moreover, we give an axiom system first-order hybrid logic.
Scalable location services for hierarchically organized mobile ad hoc networks
Authors: Siva Sivavakeesar, George Pavlou
Venue: Proceedings of the 6th ACM international symposium on Mobile ad hoc networking and computing (2005)

This paper proposes a location service to assist location-based routing protocols, realized through a novel Associativity-Based clustering protocol. The main goal of our scheme, which employs hierarchical principles, is to minimize the control traffic associated with location-management. In location-based routing protocols, the control traffic is mainly due to location-updates, queries and responses. Our scheme employs a novel geographically-oriented clustering scheme in order to minimize control traffic without impairing performance. In our location management scheme, nodes are assigned home-zones, and are required to send their location-updates to their respective home-zones through a dominating-set. This strategy, unlike similar location-management approaches, minimizes inevitable superfluous flooding by every node, and prevents location updates and queries from traversing the entire network unnecessarily, hence conserving bandwidth and transmission power. The proposed scheme is evaluated through mathematical analysis and simulations, and the results indicate that our protocol scales well with increasing node-count, node-density and node-speed.
DAC INSIDER'S GUIDE
Authors: Pat Hefferan
Venue: ACM SIGDA Newsletter (1992)

The 29th Design Automation Conference (DAC) will be held in Anaheim, California, from June 8 through June 12. Anaheim is also the home of Disney Land, a popular vacation destination. The year, the IEEE/Circuits amp; Systems Society will join in sponsoring the conference.
Experiments in multi-modal automatic content extraction
Authors: Lance Ramshaw, Elizabeth Boschee, Sergey Bratus, Scott Miller, Rebecca Stone, Ralph Weischedel, Alex Zamanian
Venue: Proceedings of the first international conference on Human language technology research (2001)

Unlike earlier information extraction research programs, the new ACE (Automatic Content Extraction) program calls for entity extraction by identifying and linking all of the mentions of an entity in the source text, including names, descriptions, and pronouns. Coreference is therefore a key component. BBN has developed statistical co-reference models for this task, including one for pronoun co-reference that we describe here in some detail. In addition, ACE calls for extraction not just from clean text, but also from noisy speech and OCR input. Since speech recognizer output includes neither case nor punctuation, we have extended our statistical parser to perform sentence breaking integrated with parsing in a probabilistic model.
Detection of clustered microcalcifications on mammograms using new filter bank
Authors: Ryohei Nakayama, Yoshikazu Uchiyama, Koji Yamamoto, Ryoji Watanabe, Kiyoshi Namba
Venue: Systems and Computers in Japan (2005)

We have developed a computer-aided diagnosis scheme for detection of clustered microcalcifications at the early stage in mammograms. In the proposed method, the mammogram image is input to a filter bank for detecting nodular&sol;line patterns. Then, the nodular pattern-enhanced image, the nodular&sol;line pattern-enhanced image, and the second-order difference images for horizontal, vertical, and diagonal directions are generated at each resolution level. Next, the mammogram image is partitioned into regions of interest (5 mm &times; 5 mm). For each region of interest, based on the images generated from the filter bank at each resolution level, the objective features are extracted and used to discriminate the region of interest containing the clustered microcalcifications and the region of interest for normal tissue. Finally, discriminant analysis using these objective features is employed for detecting the clustered microcalcifications. A detection experiment was performed using 59 mammograms containing 106 clustered microcalcifications at the early stage; the sensitivity was 94.3&percnt; (100&sol;106 clustered microcalcifications), the number of false positives was 0.051 per image, indicating that the proposed method is useful in detecting clustered microcalcifications at the early stage. &copy; 2005 Wiley Periodicals, Inc. Syst Comp Jpn, 36(5): 68&ndash;79, 2005; Published online in Wiley InterScience (). DOI 10.1002&sol;scj.20172
Conjunctive queries over trees
Authors: Georg Gottlob, Christoph Koch, Klaus U. Schulz
Venue: Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems (2004)

We study the complexity and expressive power of conjunctive queries over unranked labeled trees, where the tree structure are represented using "axis relations" such as "child", "descendant", and "following" (we consider a superset of the XPath axes) as well as unary relations for node labels. (Cyclic) conjunctive queries over trees occur in a wide range of data management scenarios related to XML, the Web, and computational linguistics. We establish a framework for characterizing structures representing trees for which conjunctive queries can be evaluated efficiently. Then we completely chart the tractability frontier of the problem for our axis relations, i.e., we find all subset maximal sets of axes for which query evaluation is in polynomial time. All polynomial-time results are obtained immediately using the proof techniques from our framework. Finally, we study the expressiveness of conjunctive queries over trees and compare it to the expressive power of fragments of XPath. We show that for each conjunctive query, there is an equivalent acyclic positive query (i.e., a set of acyclic conjunctive queries), but that in general this query is not of polynomial size.
A probabilistic model of computing with words
Authors: Daowen Qiu, Huaiqing Wang
Venue: Journal of Computer and System Sciences (2005)

Computing in the traditional sense involves inputs with strings of numbers and symbols rather than words, where words mean probability distributions over input alphabet, and are different from the words in classical formal languages and automata theory. In this paper our goal is to deal with probabilistic finite automata (PFAs), probabilistic Turing machines (PTMs), and probabilistic context-free grammars (PCFGs) by inputting strings of words (probability distributions). Specifically, (i) we verify that PFAs computing strings of words can be implemented by means of calculating strings of symbols (Theorem 1); (ii) we elaborate on PTMs with input strings of words, and particularly demonstrate by describing Example 2 that PTMs computing strings of words may not be directly performed through only computing strings of symbols, i.e., Theorem 1 may not hold for PTMs; (iii) we study PCFGs and thus PRGs with input strings of words, and prove that Theorem 1 does hold for PCFRs and PRGs (Theorem 2); a characterization of PRGs in terms of PFAs, and the equivalence between PCFGs and their Chomsky and Greibach normal forms, in the sense that the inputs are strings of words, are also presented. Finally, the main results obtained are summarized, and a number of related issues for further study are raised.
Datalog programs and their persistency numbers
Authors: Foto Afrati, Stavros Cosmadakis, Eugénie Foustoucos
Venue: ACM Transactions on Computational Logic (TOCL) (2005)

The relation between Datalog programs and homomorphism problems and between Datalog programs and bounded treewidth structures has been recognized for some time and given much attention recently. Additionally, the essential role of persistent variables (of program expansions) in solving several relevant problems has also started to be observed. It turns out that to understand the contribution of these persistent variables to the difficulty of some expressibility problems, we need to understand the interrelationship among different notions of persistency numbers, some of which we introduce and/or formalize in the present work.This article is a first foundational study of the various persistency numbers and their interrelationships. To prove the relations among these persistency numbers, we had to develop some nontrivial technical tools that promise to help in proving other interesting results too. More precisely, we define the adorned dependency graph of a program, a useful tool for visualizing sets of persistent variables, and we define automata that recognize persistent sets in expansions.We start by elaborating on finer definitions of expansions and queries, which capture aspects of homomorphism problems on bounded treewidth structures. The main results of this article are (a) a program transformation technique, based on automata-theoretic tools, which manipulates persistent variables (leading, in certain cases, to programs of fewer persistent variables); (b) a categorization of the different roles of persistent variables; this is done by defining four notions of persistency numbers which capture the propagation of persistent variables from a syntactical level to a semantical one; (c) decidability results concerning the syntactical notions of persistency numbers that we have defined; and (d) the exhibition of new classes of programs for which boundedness is undecidable.
Software system of the earth simulator
Authors: Takashi Yanagawa, Kenji Suehiro
Venue: Parallel Computing (2004)

The Earth Simulator (ES) is a large scale, distributed memory, parallel computer system consisting of 640 processor nodes (PN) with shared memory vector multiprocessors (64GFLOPS/PN, 5120 APs in total, AP: arithmetic processor). All the nodes are connected via a high speed (16GB/s) single-stage crossbar network called the Interconnection Network (IN).The operating system for the Earth Simulator is based on SUPER-UX, the UNIX operating system for the SX series scientific supercomputers. In order to realize high-performance parallel processing on the highly parallel machine, the operating system is enhanced for scalability.The Earth Simulator system is managed as a two-level cluster system called the Super Cluster System. In the Super Cluster System, the Earth Simulator system is divided into 40 clusters (16PNs/cluster). A single controller called Super Cluster Control Station (SCCS) manages all these clusters. This management system provides Single System Image (SSI) operation, management and job control for the large scale multi-node system.The Job Scheduler (JS) and NQS running on the SCCS control all jobs of the system. They schedule the resources such as processing nodes and files which have not usually been treated as scheduling resources. This allows efficient scheduling of large scale jobs.The MPI library (MPI/ES) and the HPF compiler (HPF/ES) are available for distributed parallel programming on the Earth Simulator. MPI/ES conforms to the MPI 2.0 standard and is optimized to exploit the hardware features. HPF/ES conforms to the core part of HPF 2.0 and supports some features of the HPF 2.0 approved extensions and HPF/JA 1.0 extensions. HPF/ES suitably handles the 3-level parallelism of the Earth Simulator system, that is, vectorization, shared-memory parallelization, and distributed-memory parallelization. Moreover, HPF/ES extends the language to easily handle irregular problems.
Grasping determination experiments within the UJI robotics telelab
Authors: Raul Marín, Pedro J. Sanz
Venue: Journal of Robotic Systems (2005)

As a result of new technology becoming available it is increasingly possible to develop more natural human-robot interfaces. In particular, interaction channels based on both voice and synthesis recognition, and combined with other sensors, mainly computer vision, are now implemented in current robots. These capabilities enable a more natural face-to-face dialogue in the human-robot interaction. Currently, they are demonstrating their potential in many service robot applications, such as museums, hospitals, and so on. One area where these new forms of interaction have been extensively tested recently is within the educational robotics context. This article addresses a novel user-interface implemented in such a system developed in our lab, namely &ldquo;The UJI Robotics Telelab&rdquo;, where the word UJI is the acronym for the name of our University. In order to develop this kind of complex system, several years of intensive research have been necessary in both multimedia tutoring systems and robotics. The principal motive for the project was the experimentation and validation of a complete telelaboratory, including an Internet-based robot system, with off-line and on-line control possibilities, and other different facilities (e.g., multimedia tutorial, chat channel, etc.) aimed at teaching undergraduate students in the robotics subject in our university campus. Finally, taking into account experience gained from using this system for regular undergraduate courses in robotics, new facilities have been implemented, and results showing the user performance, usability, and reliability of this novel contribution are discussed, including its advantages and limitations. &copy; 2005 Wiley Periodicals, Inc.
Static Techniques for Concept Location in Object-Oriented Code
Authors: Andrian Marcus, Vaclav Rajlich, Joseph Buchta, Maksym Petrenko, Andrey Sergeyev
Venue: Proceedings of the 13th International Workshop on Program Comprehension (2005)

Concept location in source code is the process that identifies where a software system implements a specific concept. While it is well accepted that concept location is essential for the maintenance of complex procedural code like code written in C, it is much less obvious whether it is also needed for the maintenance of the Object-Oriented code. After all, the Object-Oriented code is structured into classes and well-designed classes already implement concepts, so the issue seems to be reduced to the selection of the appropriate class. The objective of our work is to see if the techniques for concept location are still needed (they are) and whether Object-Oriented structuring facilitates concept location (it does not). This paper focuses on static concept location techniques that share common prerequisites and are search the source code using regular expression matching, or static program dependencies, or information retrieval. The paper analyses these techniques to see how they compare to each other in terms of their respective strengths and weaknesses.
Analysis of Typed Analyses of Authentication Protocols
Authors: Michele Bugliesi, Riccardo Focardi, Matteo Maffei
Venue: Proceedings of the 18th IEEE workshop on Computer Security Foundations (2005)

This paper contrasts two existing type-based techniques for the analysis of authentication protocols. The former, proposed by Gordon and Jeffrey, uses dependent types for nonces and cryptographic keys to statically regulate the way that nonces are created and checked in the authentication exchange. The latter, proposed by the authors, relies on a combination of static and dynamic typing to achieve similar goals. Specifically, the type system employs dependent ciphertext types to statically define certain tags that determine the typed structure of the messages circulated in the authentication exchange. The type tags are then checked dynamically to verify that each message has the format expected at the corresponding step of the authentication exchange. This paper compares the two approaches, drawing on a translation of tagged protocols, validated by our system, into protocols that type check with Gordon and Jeffreyýs system. This translation gives new insight into the trade-offs between the two techniques, and on their relative expressiveness and precision. In addition, it allows us to port verification techniques from one setting to the other.
Finding the boundaries of information resources on the web
Authors: Pavel Dmitriev, Carl Lagoze, Boris Suchkov
Venue: Special interest tracks and posters of the 14th international conference on World Wide Web (2005)

In recent years, many algorithms for the Web have been developed that work with information units distinct from individual web pages. These include segments of web pages or aggregation of web pages into web communities. Using these logical information units has been shown to improve the performance of many web algorithms. In this paper, we focus on a type of logical information units called compound documents. We argue that the ability to identify compound documents can improve information retrieval, automatic metadata generation, and navigation on the Web. We propose a unified framework for identifying the boundaries of compound documents, which combines both structural and content features of constituent web pages. The framework is based on a combination of machine learning and clustering algorithms, with the former algorithm supervising the latter one. Experiments on a collection of educational web sites show that our approach can reliably identify most of the compound documents on these sites.
PROTOCOL ANALYSIS OF THE USE OF A CAD SYSTEM IN A HOME DESIGN TASK
Authors: Armin Bruderlin, John Dickinson, John Dill, Lyn Bartram
Venue: ACM SIGCHI Bulletin (1991)

The question of how humans design has been approached from a number of perspectives. Analyses have been made of the processes, strategies and problem solving techniques utilized when generating new designs [Finger 89]. One descriptive method to understanding the design process is the use of protocol analysis. This method has been successfully applied to elucidate the stages and decisions inherent in design (see, for instance, [Ullman 86, Adelson 89, Schon 88]).
Approximately uniform random sampling in sensor networks
Authors: Boulat A. Bash, John W. Byers, Jeffrey Considine
Venue: Proceeedings of the 1st international workshop on Data management for sensor networks: in conjunction with VLDB 2004 (2004)

Recent work in sensor databases has focused extensively on distributed query problems, notably distributed computation of aggregates. Existing methods for computing aggregates broadcast queries to all sensors and use in-network aggregation of responses to minimize messaging costs. In this work, we focus on uniform random sampling across nodes, which can serve both as an alternative building block for aggregation and as an integral component of many other useful randomized algorithms. Prior to our work, the best existing proposals for uniform random sampling of sensors involve contacting all nodes in the network. We propose a practical method which is only approximately uniform, but contacts a number of sensors proportional to the diameter of the network instead of its size. The approximation achieved is tunably close to exact uniform sampling, and only relies on well-known existing primitives, namely geographic routing, distributed computation of Voronoi regions and von Neumann's rejection method. Ultimately our sampling algorithm has the same worst-case asymptotic cost as routing a point-to-point message, and thus it is asymptotically optimal among request/reply-based sampling methods. We provide experimental results demonstrating the effectiveness of our algorithm on both synthetic and real sensor topologies.