ppxscal/embedding_network huggingface dataset:
Immutability specification and its applications: Research Articles
Authors: Igor Pechtchanski, Vivek Sarkar
Venue: Concurrency and Computation: Practice Experience (2005)

A location is said to be immutable if its value and the values of selected locations reachable from it are guaranteed to remain unchanged during a specified time interval. We introduce a framework for immutability specification, and discuss its application to code optimization. Compared with a final declaration, an immutability assertion in our framework can express a richer set of immutability properties along three dimensions&mdash;lifetime, reachability and context. We present a framework for processing and verifying immutability annotations in Java, as well as extending optimizations so as to exploit immutability information. Preliminary experimental results show that a significant number (61&percnt;) of read accesses could potentially be classified as immutable in our framework. Further, use of immutability information yields substantial reductions (33&ndash;99&percnt;) in the number of dynamic read accesses, and also measurable speedups in the range of 5&ndash;10&percnt; for certain benchmark programs. Copyright &copy; 2005 John Wiley & Sons, Ltd.
Using Leader-Based Communication to Improve the Scalability of Single-Round Group Membership Algorithms
Authors: Roger Khazan, Sophia Yuditskaya
Venue: Proceedings of the 19th IEEE International Parallel and Distributed Processing Symposium (IPDPS'05) - Workshop 16 - Volume 17 (2005)

Sigma, the first single-round group membership (GM) algorithm, was recently introduced and demonstrated to operate consistently with theoretical expectations in a simulated WAN environment. Sigma achieved similar quality of membership configurations as existing algorithms but required fewer message exchange rounds. We now consider Sigma in terms of scalability. Sigma involves all-to-all (A2A) type of communication among members. A2A protocols have been shown to perform worse than leader-based (LB) protocols in certain networks, due to greater message overhead and higher likelihood of message loss. Thus, although LB protocols often involve additional communication steps, they can be more efficient in practice, particularly in fault-prone networks with large numbers of participating nodes. In this paper, we present Leader-Based Sigma, which transforms the original all-to-all version into a more scalable centralized communication scheme, and discuss the rounds vs. messages tradeoff involved in optimizing GM algorithms for deployment in large-scale, fault-prone dynamic network environments.
A Real-Time Iteration Scheme for Nonlinear Optimization in Optimal Feedback Control
Authors: Moritz Diehl, Hans Georg Bock, Johannes P. Schlöder
Venue: SIAM Journal on Control and Optimization (2005)

An efficient Newton-type scheme for the approximate on-line solution of optimization problems as they occur in optimal feedback control is presented. The scheme allows a fast reaction to disturbances by delivering approximations of the exact optimal feedback control which are iteratively refined during the runtime of the controlled process. The contractivity of this real-time iteration scheme is proven, and a bound on the loss of optimality---compared with the theoretical optimal solution---is given. The robustness and excellent real-time performance of the method is demonstrated in a numerical experiment, the control of an unstable system, namely, an airborne kite that shall fly loops.
Spatiograms versus Histograms for Region-Based Tracking
Authors: Stanley T. Birchfield, Sriram Rangarajan
Venue: Proceedings of the 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'05) - Volume 2 - Volume 02 (2005)

We introduce the concept of a spatiogram, which is a generalization of a histogram that includes potentially higher order moments. A histogram is a zeroth-order spatiogram, while second-order spatiograms contain spatial means and covariances for each histogram bin. This spatial information still allows quite general transformations, as in a histogram, but captures a richer description of the target to increase robustness in tracking. We show how to use spatiograms in kernel-based trackers, deriving a mean shift procedure in which individual pixels vote not only for the amount of shift but also for its direction. Experiments show improved tracking results compared with histograms, using both mean shift and exhaustive local search.
Comparisons of genetic algorithms for timetabling problems
Authors: Hiroaki Ueda, Daisuke Ouchi, Kenichi Takahashi, Tetsuhiro Miyahara
Venue: Systems and Computers in Japan (2004)

We compare genetic algorithms (GA) that solve timetabling problems for universities. Here, we define a timetabling problem as that of finding both a class schedule and room allocation that do not conflict with any constraints. We have already proposed the TGA, which evolves two kinds of genotypes, one related to class scheduling, the other related to room allocation. However, TGA has not been applied to many kinds of problems and it has not been compared with other methods. Here, we present four kinds of genetic algorithms, TGA, STGA, SGA, and SGA2. TGA and STGA use the two kinds of genotypes mentioned above. TGA evolves these genotypes alternately, while STGA evolves those sequentially. SGA and SGA2 are based on the simple GA that uses one genotype. SGA evolves a population to find feasible class scheduling and room allocation, while SGA2 evolves a population to find only a feasible class schedule for which feasible room allocation is possible. These algorithms are implemented and we apply these methods to several timetabling problems generated by an automatic timetabling problem generator. We also implement two methods, SA and TS; experiments by those methods have been performed, where SA is a method based on simulated annealing and TS is a method based on Tabu search. The experimental results show that SGA2 finds feasible solutions for almost all problems, and TGA finds feasible solutions when the average number of subjects per class is high. In addition, STGA finds a feasible solution when the problem has many classes, and SA finds feasible solutions when the number of classes is small and it has many constraints and requests. 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(7): 1&ndash;12, 2004; Published online in Wiley InterScience (). DOI 10.1002&sol;scj.10682 &copy; 2004 Wiley Periodicals, Inc.
Two-Level Non-Overlapping Schwarz Preconditioners for a Discontinuous Galerkin Approximation of the Biharmonic Equation
Authors: Xiaobing Feng, Ohannes A. Karakashian
Venue: Journal of Scientific Computing (2005)

We present some two-level non-overlapping additive and multiplicative Schwarz methods for a discontinuous Galerkin method for solving the biharmonic equation. We show that the condition numbers of the preconditioned systems are of the order O( H3/h3) for the non-overlapping Schwarz methods, where h and H stand for the fine mesh size and the coarse mesh size, respectively. The analysis requires establishing an interpolation result for Sobolev norms and Poincaré--Friedrichs type inequalities for totally discontinuous piecewise polynomial functions. It also requires showing some approximation properties of the multilevel hierarchy of discontinuous Galerkin finite element spaces.
PRAW&mdash;A PRivAcy model for the Web: Research Articles
Authors: Bracha Shapira, Yuval Elovici, Adlay Meshiach, Tsvi Kuflik
Venue: Journal of the American Society for Information Science and Technology (2005)

Web navigation enables easy access to vast amounts of information and services. However, it also poses a major risk to users' privacy. Various eavesdroppers constantly attempt to violate users' privacy by tracking their navigation activities and inferring their interests and needs (profiles). Users who wish to keep their intentions secret forego useful services to avoid exposure. The computer security community has concentrated on improving users' privacy by concealing their identity on the Web. However, users may want or need to identify themselves over the Net to receive certain services but still retain their interests, needs, and intentions in private. PRAW&mdash;a PRivAcy model for the Web suggested in this paper&mdash;is aimed at hiding users' navigation tracks to prevent eavesdroppers from inferring their profiles but still allowing them to be identified. PRAW is based on continuous generation of fake transactions in various fields of interests to confuse eavesdroppers' automated programs, thus providing them false data. A privacy measure is defined that reflects the difference between users' actual profile and the profile that eavesdroppers might infer. A prototype system was developed to examine PRAW's feasibility and conduct experiments to test its effectiveness. Encouraging results and their analysis are presented, as well as possible attacks and known limitations. &copy; 2005 Wiley Periodicals, Inc.
Real-Time Video Surveillance with Self-Organizing Maps
Authors: Mohamed Dahmane, Jean Meunier
Venue: Proceedings of the 2nd Canadian conference on Computer and Robot Vision (2005)

In this paper, we present an approach for video surveillance involving (a) moving object detection, (b) tracking and (c) normal/abnormal event recognition. The detection step uses an adaptive background subtraction technique with a shadow elimination model based on the color constancy principle. The target tracking involves a direct and inverse matrix matching process. The novelty of the paper lies mainly in the recognition stage, where we consider local motion properties (flow vector), and more global ones expressed by elliptic Fourier descriptors. From these temporal trajectory characterizations, two Kohonen maps allow to distinguish normal behavior from abnormal or suspicious ones. The classification results show a 94.6 % correct recognition rate with video sequences taken by a low cost webcam. Finally, this algorithm can be fully implemented in real-time.
A New Finite Element Gradient Recovery Method: Superconvergence Property
Authors: Zhimin Zhang, Ahmed Naga
Venue: SIAM Journal on Scientific Computing (2005)

This is the first in a series of papers in which a new gradient recovery method is introduced and analyzed. It is proved that the method is superconvergent for translation invariant finite element spaces of any order. The method maintains the simplicity, efficiency, and superconvergence properties of the Zienkiewicz--Zhu patch recovery method. In addition, for uniform triangular meshes, the method is superconvergent for the linear element under the chevron pattern, and ultraconvergent at element edge centers for the quadratic element under the regular pattern. Applications of this new gradient recovery technique will be discussed in forthcoming papers.
Robust Boosting for Learning from Few Examples
Authors: Lior Wolf, Ian Martin
Venue: Proceedings of the 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'05) - Volume 1 - Volume 01 (2005)

We present and analyze a novel regularization technique based on enhancing our dataset with corrupted copies of our original data. The motivation is that since the learning algorithm lacks information about which parts of the data are reliable, it has to make more robust classification functions. Using this framework, we propose a simple addition to the gentle boosting algorithm which enables it to work with only a few examples. We test this new algorithm on a variety of datasets and show convincing results.
Offset-stack scheme and receivers for CCC-based multicarrier CDMA architecture: Research Articles
Authors: Aiping Huang, Jing Li, Shao-Bo Liu
Venue: Wireless Communications Mobile Computing (2005)

The main objective of this paper is to present new receiver structures to improve the applicability of a recently developed multicarrier CDMA architecture based on complete complementary codes. A mathematical description of the new system is presented in this paper. It is found that though it is the offset-stack scheme that guarantees high spectral efficiency and scalable rate-matching, error propagation under multipath fading noisy channel conditions is generated due to such special spreading modulation scheme and the corresponding recursive receiver. In order to avoid error propagation, the precondition of multipath replica separation is derived mathematically so that a non-recursive receiver can be employed. The range of the channel delay spread is discussed and the impact of the time shift in offset-stack spreading modulation on spectral efficiency is analyzed. Then, a RAKE receiver is proposed to further improve the performance through multipath diversity. Simulations are carried out under multipath fading noisy channel conditions to further verify the theoretical analysis. Performance loss caused by error propagation is observed by comparing the performances of the recursive receiver and the non-recursive receiver. With the same spectral efficiency, the proposed offset-stack scheme and the RAKE receiver gain obvious performance improvement compared to the existing offset-stack scheme and the recursive receiver. Copyright &copy; 2005 John Wiley & Sons, Ltd.
Program Counter Based Techniques for Dynamic Power Management
Authors: Chris Gniady, Y Charlie Hu, Yung-Hsiang Lu
Venue: Proceedings of the 10th International Symposium on High Performance Computer Architecture (2004)

Reducing energy consumption has become one of the major challenges in designing future computing systems. This paper proposes a novel idea of using program counters to predict I/O activities in the operating system. The paper presents a complete design of Program-Counter Access Predictor (PCAP) that dynamically learns the access patterns of applications and predicts when an I/O device can be shut down to save energy. PCAP uses path-based correlation to observe a particular sequence of program counters leading to each idle period, and predicts future occurrences of that idle period. PCAP differs from previously proposed shutdown predictors in its ability to: (1) correlate I/O operations to particular behavior of the applications and users, (2) carry prediction information across multiple executions of the applications, and (3) attain better energy savings while incurring low mispredictions.
A grading dilemma or the abyss between sorting and the knapsack problem
Authors: Robert W. McGrail, Tracey Baldwin McGrail
Venue: Journal of Computing Sciences in Colleges (2004)

This paper attempts to provide a solution to a seemingly simple grading problem. It introduces a notion of sorting for lists of weighted grades and puts forward an algorithmic candidate for this task. The paper then goes on to discuss the reliability of this algorithm and concludes with suggestions for student research. It is noted that the problem has similarities to both sorting and the knapsack problem and can be a nice addition to a course on algorithms.
Towards an Efficient and Scalable Discontinuous Galerkin Atmospheric Model
Authors: J. M. Dennis, M. Levy, R. D. Nair, H. M. Tufo, T. Voran
Venue: Proceedings of the 19th IEEE International Parallel and Distributed Processing Symposium (IPDPS'05) - Workshop 13 - Volume 14 (2005)

An efficient and scalable Discontinuous Galerkin shallow water model on the cubed sphere is developed by extending the transport scheme of Nair et al.The continuous flux form nonlinear shallow water equations in curvilinear coordinates are developed.Spatial discretization is a nodal basis set of Legendre polynomials.Fluxes along internal element interfaces are approximated by a Lax-Friedrichs scheme.A third-order total variation diminishing Runge-Kutta scheme is applied for time integration, without any filter or limiter.The standard shallow-water test suite of Williamson et al. is used to validate the model.It is observed that the numberical solutions are accurate, the model conserves mass to machine precision, and there are no spurious oscillations in a test case where zonal flow impinges a mountain.Development time was substantially reduced by building the model in the High Order Method Modeling Environment (HOMME) developed at the National Center for Atmospheric Research (NCAR).Performance and scaling data for the steady state geostrophic flow problem is presented. Sustained performance in excess of 10% of peak is observed out to 64 processors on a Linux cluster.
A mediation framework for multimedia delivery
Authors: Onyeka Ezenwoye, Raimund K. Ege, Li Yang, Qasem Kharma
Venue: Proceedings of the 3rd international conference on Mobile and ubiquitous multimedia (2004)

We present a conceptual mediation framework that features three layers of mediators: presence, integration, and homogenization layers that work together in a peer-to-peer (p2p) manner to facilitate the delivery of multimedia data. On arrival of each request for data from a client, a global-mediator is elected from a group of integration layer mediators to service that request. Using distributed hash table (DHT), the global-mediator dispatches the request to other integrator mediators to track down the data sources. Upon receipt of the results, from the source(s), the global-mediator presents the data to the client via a presence-mediator. The presence-mediator may need to reformat the data to suit the execution context of the client. This mediation process is context-aware, adaptive and dynamically structured. Quality of service (QoS) factors are taken into consideration in the retrieval and presentation of data.
Model replication techniques for parameter-influence studies and Monte Carlo simulation with random parameters
Authors: Granino A. Korn
Venue: Mathematics and Computers in Simulation (2005)

Modern computers produce large volumes of simulation results so quickly that their management becomes a formidable task. We describe interactive computer software for replicating simulation models with different parameters. A single simulation run then produces results for hundreds of models with different parameter values without the loop overhead imposed by repeated simulations. One can1.arrange corresponding values of model-parameter values and model performance measures in corresponding arrays suitable for use in commercially available spreadsheet and relational-database programs for further processing and archival storage, or 2.produce a Monte Carlo sample of model runs with random parameter values and compute statistics such as various averages or probability estimates as functions of simulation time in a single simulation run.
Dependability assessment of software-based systems: state of the art
Authors: Bev Littlewood
Venue: Proceedings of the 27th international conference on Software engineering (2005)

My talk will present a personal and rather selective view of the state of the art of some aspects of dependability assessment for software-based systems. This short note gives a brief outline of the issues I shall address.
Security-Driven Heuristics and A Fast Genetic Algorithm for Trusted Grid Job Scheduling
Authors: Shanshan Song, Yu-Kwong Kwok, Kai Hwang
Venue: Proceedings of the 19th IEEE International Parallel and Distributed Processing Symposium (IPDPS'05) - Papers - Volume 01 (2005)

In this paper, our contributions are two-fold: First, we enhance the Min-Min and Sufferage heuristics under three risk modes driven by security concerns. Second, we propose a new Space-Time Genetic Algorithm (STGA) for trusted job scheduling, which is very fast and easy to implement. Under our new model, a job can possibly fail if the site security level is lower than the job security demand. We consider three security-driven heuristic modes: secure, risky, and f-risky. The secure mode always dispatches jobs to secure sites meeting the job security demands. The risky mode allocates jobs to any available resource site, taking whatever the risk it may face. The f-risky mode tries to limit the risk to be at most certain probability f. Our extensive simulation results indicated that the proposed STGA is highly effective in scheduling two types of practical workloads: NAS (Numerical Aerodynamic Simulation) and PSA (parametersweep application). The STGA outperforms the Min-Min and Sufferage heuristics under three risk modes, in terms of a wide range of performance metrics including makespan, average response time, site utilization, slowdown ratio, and job failure rate.
MRNet: A Software-Based Multicast/Reduction Network for Scalable Tools
Authors: Philip C. Roth, Dorian C. Arnold, Barton P. Miller
Venue: Proceedings of the 2003 ACM/IEEE conference on Supercomputing (2003)

We present MRNet, a software-based multicast/reduction network for building scalable performance and system administration tools. MRNet supports multiple simultaneous, asynchronous collective communication operations. MRNet is flexible, allowing tool builders to tailor its process network topology to suit their tool's requirements and the underlying system's capabilities. MRNet is extensible, allowing tool builders to incorporate custom data reductions to augment its collection of built-in reductions. We evaluated MRNet in a simple test tool and also integrated into an existing, real-world performance tool with up to 512 tool back-ends. In the real-world tool, we used MRNet not only for multicast and simple data reductions but also with custom histogram and clock skew detection reductions. In our experiments, the MRNet-based tools showed significantly better performance than the tools without MRNet for average message latency and throughput, overall tool start-up latency, and performance data processing throughput.
A Haptic Interface for Human-in-the-Loop Manipulation at the Nanoscale
Authors: Hong Z. Tan, Laron Walker, Ron Reifenberger, Sorubh Mahadoo, George Chiu, Arvind Raman, Aron Helser, Pablo Colilla
Venue: Proceedings of the First Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (2005)

This paper outlines major challenges that we are facing in interfacing a human user with objects in the nanoworld via a haptic interface. After a review of prior efforts at haptically-enabled nanomanipulation systems, we present the current state of our nanomanipulator system. We then discuss current research issues including the direct-Z mode, force modeling, data transfer rates and the stability of the haptic interface. Results of nanomanipulation of single-walled carbon nanotubes are presented. It is our hope that the insight gained by the human user of a haptic interface to SPM will lead to scanning algorithms that can automatically adjust the SPM parameters based on the properties of the nanosample and the substrate under investigation.
Towards Exploring Interactive Relationship between Clusters and Outliers in Multi-Dimensional Data Analysis
Authors: Yong Shi, Aidong Zhang
Venue: Proceedings of the 21st International Conference on Data Engineering (2005)

Nowadays many data mining algorithms focus on clustering methods. There are also a lot of approaches designed for outlier detection. We observe that, in many situations, clusters and outliers are concepts whose meanings are inseparable to each other, especially for those data sets with noise. Thus, it is necessary to treat clusters and outliers as concepts of the same importance in data analysis. In this paper, we present a cluster-outlier iterative detection algorithm, tending to detect the clusters and outliers in another perspective for noisy data sets. In this algorithm, clusters are detected and adjusted according to the intra-relationship within clusters and the inter-relationship between clusters and outliers, and vice versa. The adjustment and modification of the clusters and outliers are performed iteratively until a certain termination condition is reached. This data processing algorithm can be applied in many fields such as pattern recognition, data clustering and signal processing. Experimental results demonstrate the advantages of our approach.