ppxscal/embedding_network huggingface dataset:
PHANToM haptic device implemented in a projection screen virtual environment
Authors: A. Fischer, J. M. Vance
Venue: Proceedings of the workshop on Virtual environments 2003 (2003)

This research combines the PHANToM 1.5 haptic device with a six-sided projection screen virtual environment in order to explore the benefits haptic devices bring to this type of immersive environment. The PHANToM is placed on a specially designed and constructed work stand which allows the device to be moved anywhere in the virtual environment. An algorithm has been developed which maps the size of the CAD model represented in the virtual environment, or the movement of the CAD model, to the working space of the PHANToM. Two applications are explored which illustrate using the PHANToM for different tasks: exploring a large NURBS surface and installing an aircraft rudder pedal assembly.
An event routing service for distributed applications: computer telephony-a case study
Authors: Bartosz Klimek, Dominik Radziszowski, Krzysztof Zieliński
Venue: Software&mdash;Practice Experience (2002)

This paper presents an event routing service (ERS) that represents a pattern for the establishment and processing of lightweight sessions between a source and a destination of events. It is based on the CORBA notification service. To illustrate the features of the proposed service, its application in computer telephony is discussed in detail. Most of the positive features of the ERS are inherited from the CORBA notification service, but its implementation requires a novel protocol describing the lightweight session establishment mechanism. The implementation of ERS is described and its application to routing events in a computer telephony system is presented. The paper concludes with a performance measurement study.
Message passing and shared address space parallelism on an SMP cluster
Authors: Hongzhang Shan, Jaswinder P. Singh, Leonid Oliker, Rupak Biswas
Venue: Parallel Computing (2003)

Currently, message passing (MP) and shared address space (SAS) are the two leading parallel programming paradigms. MP has been standardized with MPI, and is the more common and mature approach; however, code development can be extremely difficult, especially for irregularly structured computations. SAS offers substantial ease of programming, but may suffer from performance limitations due to poor spatial locality and high protocol overhead. In this paper, we compare the performance of and the programming effort required for six applications under both programming models on a 32-processor PC-SMP cluster, a platform that is becoming increasingly attractive for high-end scientific computing. Our application suite consists of codes that typically do not exhibit scalable performance under shared-memory programming due to their high communication-to-computation ratios and/or complex commumcation patterns. Results indicate that SAS can achieve about half the parallel efficiency of MPI for most of our applications, while being competitive for the others. A hybrid MPI + SAS strategy shows only a small performance advantage over pure MPI in some cases. Finally, improved implementations of two MPI collective operations on PC-SMP clusters are presented.
A soft design of acceptance sampling plans by variables
Authors: Przemyslaw Grzegorzewski
Venue: Technologies for constructing intelligent systems: tools (2002)

A soft method for designing single sampling plans by variables with relaxed quality levels is suggested. Since small deviations of the parameter from its target value are very often of no importance our soft method for designing sampling plans is more flexible than the conventional one.
Resource optimization of CDMA systems for supporting integrated voice and data traffic
Authors: Mainak Chatterjee, Sajal K. Das
Venue: Journal of High Speed Networks (2002)

In this paper, we optimize the usage of both control and traffic channels of a CDMA system by switching the MAC states of a service. In particular, we find the optimal transition timers for a cdma2000 system supporting integrated voice and data traffic. This is achieved by optimizing a composite performance metric defined as a multi-objective function of channel utilization, waiting time and the saving in the signalling overhead. First, we try to characterize wireless data as a mix of of Poisson-distributed voice packets and Pareto-distributed data packets, and study the effect of the composition of the mix and the shape parameter of Pareto distribution on the system performance. Then we derive analytical expressions for the composite performance metric with a goal to obtain the optimal values of expiration timers at which the MAC states should be switched such that the system performance is maximized. Since a closed form solution could not be obtained due to the transcendental nature of the analytical expression, simulation experiments are conducted to confirm the analysis.
A Hybrid Tabu Search/Branch-and-Bound Algorithm for the Direct Flight Network Design Problem
Authors: Klaus Büdenbender, Tore Grünert, Hans-Jürgen Sebastian
Venue: Transportation Science (2000)

This paper introduces a network design problem with a structure that is encountered in many transportation processes. The general organization of these systems is as follows. Freight has to be transported between a large number of origins and destinations. To consolidate the freight, it is first shipped to a terminal. Next, it is transported directly to a terminal where it is re-loaded and shipped to its destination. The task is to decide which terminals have to be used and how the freight is transported among the terminals. We describe an application where the terminals are airports and the freight is letter mail. Here, the transportation between terminals is by air, which is required due to temporal constraints. The economical impact of these decisions is huge because air transportation is costly and the process is repeated every night. We show how the problem can be modeled as a capacitated warehouse location problem with side constraints and propose a hybrid Tabu Search/Branch-and-Bound algorithm, which solves large real-world instances with acceptable computation times.
Verifying authentication protocol implementations
Authors: Steve Schneider
Venue: Proceedings of the IFIP TC6/WG6.1 Fifth International Conference on Formal Methods for Open Object-Based Distributed Systems V (2002)

Formal methods for verifying authentication protocols tend to assume an idealised, perfect form of encryption. This approach has been spectacularly successful in finding flaws, but when we aim for proofs of correctness then we need to consider this assumption more carefully, and perhaps to weaken it to reflect properties of real cryptographic mechanisms. This paper reviews the existing CSP approach to verifying protocols, and considers how algebraic properties of real cryptographic mechanisms can be incorporated within a rank function verification. The approach is illustrated with an authentication protocol which makes use of exclusive-or.
A portable thread API for teaching operating systems
Authors: Jeffrey D. Martens
Venue: Journal of Computing Sciences in Colleges (2003)

When teaching a course that includes programming assignments, it can be expedient to allow students a choice in programming language and operating systems, e.g. Java or C++, Windows or Linux, etc. In addition to saving classroom time, this allows the student to focus on the problem at hand, as opposed to an unfamiliar environment or language. To support such flexibility in an introductory OS course, I provide C++ programmers with a Java-like thread API and semaphore and pipe classes, all of which work under both Linux or Windows. Similarly, I supply semaphore and pipe classes for Java programmers. The result is that students in all three camps are using the same APIs and terminology, which greatly facilitates class discussion.
Operability Restoration Procedure for Fault-Tolerant Digital Systems with Dynamic Redundancy
Authors: V. A. Vedeshenkov
Venue: Automation and Remote Control (2003)

A procedure was developed to restore operability of the fault-tolerant digital systems with dynamic redundancy. A method of reconfiguration of the fault-tolerant graph, which allows one to use the redundant chords to eliminate the effect of the faulty chords of the working configurations of graph, was described. Indiscriminability of the faults of adjacent components does not inhibit restoration of operability of the fault-tolerant systems with dynamic redundancy. A procedure of single diagnosis of faulty components was developed with regard for the characteristics of the model. For some fault situations of the 2-fault-tolerant vertex 3-cube, examples of realization of the main stages of the restoration procedure&mdash;diagnosis of the faulty components and change of the working configurations&mdash;were presented.
Who wants to know what when? privacy preference determinants in ubiquitous computing
Authors: Scott Lederer, Jennifer Mankoff, Anind K. Dey
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

We conducted a questionnaire-based study of the relative importance of two factors, inquirer and situation, in determining the preferred accuracy of personal information disclosed through a ubiquitous computing system. We found that privacy preferences varied by inquirer more than by situation. That is, individuals were more likely to apply the same privacy preferences to the same inquirer in different situations than to apply the same privacy preferences to different inquirers in the same situation. We are applying these results to the design of a user interface for managing everyday privacy in ubiquitous computing.
Domain decomposition method for contact problems with small range contact
Authors: Josef Daněk
Venue: Mathematics and Computers in Simulation (2003)

A non-overlapping domain decomposition algorithm of Neumann-Neumann type for solving variational inequalities arising from the elliptic boundary value problems in two dimensions with unilateral boundary condition is presented. We suppose that boundary with inequality condition is 'relatively' small. First, the linear auxiliary problem, where the inequality condition is replaced by the equality condition, is solved. In the second step, the solution of the auxiliary problem is used in a successive approximations method. In these solvers, a preconditioned conjugate gradient method with Neumann-Neumann preconditioner is used for solving the interface problems, while local problems within each subdomain are solved by direct solvers. A convergence of the iterative method is proved and results of computational test are reported.
Nonlinearity of Boolean Functions and Hyperelliptic Curves
Authors: Jung Hee Cheon, Seongtaek Chee
Venue: SIAM Journal on Discrete Mathematics (2003)

We give a novel relationship between the nonlinearity of rational functions over $\mathbb{F}_{2^n}$ and the number of points of the associated hyperelliptic curve. Using this, we obtain a lower bound on the nonlinearity for rational functions over $\mathbb{F}_{2^n}$. Compared to previous work that provides a lower bound on the nonlinearity only for monomials of special types, our result gives a general bound applicable to all rational functions defined over $\mathbb{F}_{2^n}$. By applying this result, we get a lower bound on the nonlinearity for various n &times; kn S-boxes.
A Column Generation Approach for Large-Scale Aircrew Rostering Problems
Authors: Gerard Cornuejols, Milind Dawande, Michel Gamache, Francois Soumis, Gerald Marquis, Jacques Desrosiers
Venue: Operations Research (1999)

This article describes a method for solving the crew rostering problem in air transportation. This problem consists of constructing personalized schedules that assign pairings, days off, and other activities to airline crew members. A generalized set partitioning model and a method using column generation have been used. This method has been adapted in a number of ways to take advantage of the nature of the problem and to accelerate solution. Numerical tests on problems from Air France have demonstrated that this method is capable of solving very large scale problems with thousands of constraints and hundreds of subproblems. The tests have also shown that these adaptations are capable of reducing solution time by a factor of about a thousand. Finally, results from this method are compared with those obtained with the method currently used at Air France.
Constructing Edge-Disjoint Spanning Trees in Product Networks
Authors: Shan-Chyun Ku, Biing-Feng Wang, Ting-Kai Hung
Venue: IEEE Transactions on Parallel and Distributed Systems (2003)

A Cartesian product network is obtained by applying the cross operation on two graphs. In this paper, we study the problem of constructing the maximum number of edge-disjoint spanning trees (abbreviated to EDSTs) in Cartesian product networks. LetG=(V_G, E_G)be a graph havingn_1EDSTs andF=(V_F, E_F)be a graph havingn_2EDSTs. Two methods are proposed for constructing EDSTs in the Cartesian product ofGandF , denoted byG\times F . The graphGhast_1=|E_G|-n_1(|V_G|-1)more edges than that are necessary for constructingn_1EDSTs in it, and the graphFhast_2=|E_F|-n_2(|V_F|-1)more edges than that are necessary for constructingn_2EDSTs in it. By assuming thatt_1\ge n_1andt_2 \ge n_2 , our first construction shows thatn_1+ n_2EDSTs can be constructed inG \times F . Our second construction does not need any assumption and it constructsn_1 + n_2-1EDSTs inG \times F . By applying the proposed methods, it is easy to construct the maximum numbers of EDSTs in many important Cartesian product networks, such as hypercubes, tori, generalized hypercubes, mesh connected trees, and hyper Petersen networks.
Location models for airline hubs behaving as M/D/c queues
Authors: Vladimir Marianov, Daniel Serra
Venue: Computers and Operations Research (2003)

Models are presented for the optimal location of hubs in airline networks, which take into consideration the congestion effects. Hubs, which are typically the most congested airports, are modeled as M/D/c queuing systems. A formula is derived for the probability of a number of customers in the system, which is later used to propose a capacity constraint. This constraint limits the probability of more than b airplanes in queue, to be smaller than or equal to a given value. Due to the computational complexity of the formulation, the model is solved using a heuristic based on tabu search. Computational experience is presented together with an example using a data set available in the literature.
Contrasting Structured and Random Permutation Flow-Shop Scheduling Problems: Search-Space Topology and Algorithm Performance
Authors: Jean-Paul Watson, Laura Barbulescu, L. Darrell Whitley, Adele E. Howe
Venue: INFORMS Journal on Computing (2002)

The use of random test problems to evaluate algorithm performance raises an important, and generally unanswered, question: Are the results generalizable to more realistic problems? Researchers generally assume that algorithms with superior performance on difficult, random test problems will also perform well on more realistic, structured problems. Our research explores this assumption for the permutation flow-shop scheduling problem. We introduce a method for generating structured flow-shop problems, which are modeled after features found in some real-world manufacturing environments. We perform experiments that indicate significant differences exist between the search-space topologies of random and structured flow-shop problems, and demonstrate that these differencescan affect the performance of certain algorithms. Yet despite these differences, and in contrast to difficult random problems, the majority of structured flow-shop problems were easily solved to optimality by most algorithms. For the problems not optimally solved, differences in performance were minor. We conclude that more realistic, structured permutation flow-shop problems are actually relatively easy to solve. Our results also raise doubts as to whether superior performance on difficult random scheduling problems translates into superior performance on more realistic kinds of scheduling problems.
The Proteus multiprotocol message library
Authors: Kenneth Chiu, Madhusudhan Govindaraju, Dennis Gannon
Venue: Proceedings of the 2002 ACM/IEEE conference on Supercomputing (2002)

Grid systems span manifold organizations and application domains. Because this diverse environment inevitably engenders multiple protocols, interoperability mechanisms are crucial to seamless, pervasive access. This paper presents the design, rationale, and implementation of the Proteus multiprotocol library for integrating multiple message protocols, such as SOAP and JMS, within one system. Proteus decouples application code from protocol code at run-time, allowing clients to incorporate separately developed protocols without recompiling or halting. Through generic serialization, which separates the transfer syntax from the message type, protocols can also be added independently of serialization routines. We also show performance-enhancing mechanisms for Grid services that examine metadata, but pass actual data through opaquely (such as adapters). The interface provided to protocol implementors is general enough to support protocols as disparate as our current implementations: SOAP, JMS, and binary. Proteus is written in C++; a Java port is planned.
Incremental placement for layout driven optimizations on FPGAs
Authors: Deshanand P. Singh, Stephen D. Brown
Venue: Proceedings of the 2002 IEEE/ACM international conference on Computer-aided design (2002)

This paper presents an algorithm to update the placement of logic elements when given an incremental netlist change. Specifically, these algorithms are targeted to incrementally place logic elements created by layout-driven circuit restructuring techniques. The incremental placement engine assumes that the restructuring algorithms provide a list of new logic elements along with preferred locations for each of these new elements. It then tries to shift non-critical logic elements in the original placement out of the way to satisfy the preferred location requests. Our algorithm considers modern FPGA architectures with clustered logic blocksthat have numerous architectural constraints. Experiments indicate that our technique produces results of extremely highquality.
Design, Implementation, and Performance of Checkpointing in NetSolve
Authors: Adnan Agbaria, James S. Plank
Venue: Proceedings of the 2000 International Conference on Dependable Systems and Networks (formerly FTCS-30 and DCCA-8) (2000)

While a variety of checkpointing techniques and systems has been documented for long-running programs, they are typically not available for programmers that are non-systems experts. This paper details a project that integrates three technologies, NetSolve, Starfish, and IBP, for the seamless integration of fault-tolerance into long-running applications. We discuss the design and implementation of this project, and present performance results executing on both local and wide-area networks.
A database of categories
Authors: Michael Fleming, Ryan Gunther, Robert Rosebrugh
Venue: Journal of Symbolic Computation (2003)

We describe a program which facilitates storage and manipulation of finitely-presented (FP) categories and finite-set valued functors. It allows storage, editing and recall of FP categories and functors. Several tools for testing properties of objects and arrows, and the computation of right and left Kan extensions are included. The program is written in ANSI C and is menu-based. Use of the program requires a basic knowledge of category theory.
Interactive locality optimization on NUMA architectures
Authors: Tao Mu, Jie Tao, Martin Schulz, Sally A. McKee
Venue: Proceedings of the 2003 ACM symposium on Software visualization (2003)

Optimizing the performance of shared-memory NUMA programs remains something of a black art, requiring that application writers possess deep understanding of their programs' behaviors. This difficulty represents one of the remaining hindrances to the widespread adoption and deployment of these cost-efficient and scalable shared-memory NUMA architectures. To address this problem, we have developed a performance monitoring infrastructure and a corresponding set of tools to aid in visualizing and understanding the subtleties of the memory access behavior of parallel NUMA applications with large datasets. The tools are designed to be general, interoperable, and easily portable. We give detailed examples of the use of one particular tool in the set. We have used this memory access visualization tool profitably on a range of applications, improving performance by around 90%, on average.
Optimizing web servers using page rank prefetching for clustered accesses
Authors: Victor Safronov, Manish Parashar
Venue: Information Sciences&mdash;Informatics and Computer Science: An International Journal (2003)

This paper presents a Page rank-based prefetching technique for accesses to Web page clusters. The approach uses the link structure of a requested page to determine the "most important" linked pages and to identify the page(s) to be prefetched. The underlying premise of our approach is that in the case of cluster accesses, the next pages requested by users of the Web server are typically based on the current and previous pages requested. Furthermore, if the requested pages have a lot of links to some "important" page, that page has a higher probability of being the next one requested. An experimental evaluation of the prefetching mechanism is presented using real server logs. The results show that the Page rank-based scheme does better than random prefetching for clustered accesses, with hit rates of 90% in some cases.
A Facet Generation Procedure for Solving 0/1 Integer Programs
Authors: Gyana Parija, Radu Gadidov, Wilbert Wilhelm
Venue: Operations Research (1999)

This paper presents the Facet Generation Procedure (FGP) for solving 0/1 integer programs. The FGP seeks to identify a hyperplane that represents a facet of an underlying polytope to cut off the fractional solution to the linear programming relaxation of the integer programming problem. A set of standard problems is used to provide insight into the computational characteristics of the procedure.
Controlling Decision-Making Practice in Organizations
Authors: Kathleen M. Sutcliffe, Gerry McNamara
Venue: Organization Science (2001)

How are decision practices fostered in organizations and how are they linked to decision outcomes? This study addresses these questions by examining one financial institution's efforts to standardize and control decision making across geographically separated organizational units. We argue that decision-maker behavior is situated and is not simply a function of individual choice. Rather, in organizational settings decision-makers are subject to a hierarchy of influences that affect the decision processes they use and their resulting decision choices. To test our ideas, we examined 900 borrower "risk rating" decisions and found general support for our hypotheses. Decision makers were more likely to use the prescribed practice when decisions were important, when the decision target was known, and when the decision maker was located in a larger subunit. Decision makers altered their decision practices in the short term, but in the long term they appeared to partially revert to their earlier practices. Reliance on prescribed practice fostered stability in decisions, but surprisingly appeared to negatively affect future judgments. The findings indicate that organizations can change the more microaspects of decision making, but these changes may be transitory. Moreover the results suggest that decision makers may become complacent when they rely on prescribed decision practices, a tendency that can have untoward consequences for the organizations in which they are embedded.