ppxscal/embedding_network huggingface dataset:
Design and Performance Evaluation of Efficient Consensus Protocols for Mobile Ad Hoc Networks
Authors: Weigang Wu, Jiannong Cao, Jin Yang, Michel Raynal
Venue: IEEE Transactions on Computers (2007)

Designing protocols for solving the consensus problem faces new challenges in mobile computing environments. Among others, how we can achieve message efficiency for saving resource consumption has been the focus of research. In this paper, we present the HC protocol, a message efficient consensus protocol for MANETs. We consider the widely used system model where the hosts fail by crashes and the system is equipped with Chandra-Toueg's unreliable failure detectors. Unlike existing consensus protocols, the HC protocol uses a two-layer hierarchy based on clusters to achieve message efficiency. The messages from and to the hosts in the same cluster are merged so as to reduce the message cost. However, adding such a hierarchy is not trivial. Due to host movements and failures, the hierarchy changes from time to time and this may cause message loss. In designing HC, we also propose methods to handle such message losses. Extensive simulations have been carried out to evaluate and compare the performance of the HC protocol and similar protocols in a MANET environment. Simulation results show that, in most cases, our protocol can significantly reduce both the message cost and time cost. With increases in the system scale or the percentage of faulty hosts, the advantage of our protocol becomes more obvious.
System support for scalable, reliable and highly manageable web hosting service
Authors: Mon-Yen Luo, Chu-Sing Yang
Venue: Proceedings of the 3rd conference on USENIX Symposium on Internet Technologies and Systems - Volume 3 (2001)

This paper presents the architecture and some key mechanisms of an integrated framework for providing a reliable and highly manageable Web hosting service on a scalable server cluster. We devise a novel idea termed "URL Formalizaton" and a corresponding data structure, which provide a scalable solution to the request distribution in the system. We exploit the advantages of Java to implement a management system to providing a highly manageable system. Our system supports a higher level of services reliability than other server cluster systems. The result of performance evaluation on the proposed system shows that the system is low-cost and effective.
Efficient Stack Simulation for Shared Memory Set-Associative Multiprocessor Caches
Authors: C. Eric Wu, Yarsun Hsu, Yew-Huey Liu
Venue: Proceedings of the 1993 International Conference on Parallel Processing - Volume 01 (1993)

We propose efficient stack simulation algorithms for shared memory multiprocessor (MP) caches. A stack simulation algorithm for write-updated MP caches is first presented. It produces the number of write-updates as well as misses for all cache configurations in a single run. We then devise a new stack simulation algorithm for writeinvalidate MP caches. Our algorithm takes into account cross-invalidation among processors, and generates the number of invalidations as well as misses for all cache configurations in a single run. A cache simulator based on our algorithms for MP caches is developed and the results on sample traces are reported. Our results show that effi cient stack simulation is a powerful technique for multi processor cache analysis.
A root cause analysis interface for error reporting
Authors: D. Sturm, R. S. Beiss
Venue: ACM SIGCSE Bulletin (2007)

We describe a web-based interface that facilitates entering and analyzing medical errors. It uses an interactive causal tree-building component. The interactive component allows a user to build a causal tree with any number of events and antecedents. This replaces a form-based approach that is limited to a predetermined number of events and antecedents. After the causal tree is completed, the user can save the tree to a database. Causal trees can be retrieved and rebuilt as well. We developed an algorithm that, given a data bank of reported errors, will help detect similar events. This facilitates recognizing patterns of errors.
Best view selection and compression of moving objects in IR sequences
Authors: N. Vaswani
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2001. on IEEE International Conference - Volume 03 (2001)

Remote surveillance of battlefields is an important component of future combat systems (FCS). Typically, multiple infra-red (IR) sensors are placed in the field for image acquisition from different orientations. A system for selecting a single best view image chip from an IR video sequence and compression of the chip for transmission is presented. Moving object detection was done using the algorithm described in Shekarforoush et al., (2000). Eigenspace classification has been implemented for best view selection. Fast algorithms for image chip compression have been developed in the wavelet domain by combining a non-iterative zerotree coding method with 2D-DPCM for both low and high frequency subbands and compared against existing schemes.
Ceph: a scalable, high-performance distributed file system
Authors: Sage A. Weil, Scott A. Brandt, Ethan L. Miller, Darrell D. E. Long, Carlos Maltzahn
Venue: Proceedings of the 7th USENIX Symposium on Operating Systems Design and Implementation - Volume 7 (2006)

We have developed Ceph, a distributed file system that provides excellent performance, reliability, and scalability. Ceph maximizes the separation between data and metadata management by replacing allocation tables with a pseudo-random data distribution function (CRUSH) designed for heterogeneous and dynamic clusters of unreliable object storage devices (OSDs). We leverage device intelligence by distributing data replication, failure detection and recovery to semi-autonomous OSDs running a specialized local object file system. A dynamic distributed metadata cluster provides extremely efficient metadata management and seamlessly adapts to a wide range of general purpose and scientific computing file system workloads. Performance measurements under a variety of workloads show that Ceph has excellent I/O performance and scalable metadata management, supporting more than 250,000 metadata operations per second.
Tutorial T4A: Formal Verification Techniques and Tools for Complex Designs
Authors: Jacob A. Abraham, Daniel G. Saab
Venue: Proceedings of the 20th International Conference on VLSI Design held jointly with 6th International Conference: Embedded Systems (2007)

Integrated circuit technology has evolved from micro-controllers and discrete components to fully integrating a large system on a single chip (SoC). Today, verification is the most expensive component in the design cycle in term of cost and time. This cost is estimated to consume about 70% to 80% of the total design effort. The verification cost is expected to increase for SoC designs. This is mainly due to the increase in complexity and to the shrinking of the product design cycle. For example, the color TV took over 10 years to sell 1 million units, while the DVD player took just over a year. This shrinking of the design cycle is going to put more pressure on increasing designer productivity which is affected directly by the cost of verification. For these reasons, verification of complex designs is becoming a bottleneck in the process of producing integrated SoC systems. This tutorial provides an overview of emerging directions in Formal Verification and a discussion of new tools being developed in industry and research directions to enable automated verification of next generation systems on a chip. The tutorial will begin with a comprehensive overview of techniques for formally verifying complex designs. It will include the fundamental theory, applicability to different types of VLSI designs, as well as the performance and limitations of various approaches. The focus will be on Formal methods and will include both equivalence checking and property checking. Formal equivalence checking methods (between RTL and gate levels) incorporated into industry tools will be described, as well as new techniques for checking the equivalence between Electronic System Languages (such as SystemC) and RTL. The basics of property checking techniques in existing tools will be described, including the basics of model checking, and search algorithms that automatically show the correctness/violation of a property. Limitation and benefits of both SATisfiability and Automatic Test Pattern Generation (ATPG) based Bounded Model property Checking (BMC) will be described.
Quality measurement for monochrome compressed images in the past 25 years
Authors: A. M. Eskicioglu
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2000. on IEEE International Conference - Volume 04 (2000)

While lossy image compression techniques are vital in reducing bandwidth and storage requirements, they result in distortions in compressed images. A reliable quality measure is a much needed tool for determining the type and amount of image distortion. The traditional subjective criteria, which involve human observers, are inconvenient, time-consuming, and influenced by environmental conditions. Widely used pixel wise measures such as the mean square error (MSE) cannot capture the artifacts like blurriness or blockiness, and do not correlate well with visual error perception. Attempts to improve quality measurement include incorporation of simple models of the human visual system (HVS) and multi-dimensional tool design. We review the criteria for monochrome compressed image quality from 1974 to 1999.
Note: Desarguesian nets without ovals
Authors: David A. Drake
Venue: Journal of Combinatorial Theory Series A (2007)

Let @P be the Desarguesian affine plane coordinatized by a division ring D with charD=9.
Investigating the Action of Complex Highway Noise Barriers by Means of Sound Field Visualization
Authors: David Joseph Oldham, Christopher A. Egan
Venue: Proceedings of the Computer Graphics, Imaging and Visualisation (2007)

The performance of a simple noise barrier is determined by its height relative to the heights of the noise source and receivers. There have been many attempts to overcome this limitation by modifications to the barrier top edge. These generally take the form of an absorbent top or the introduction of additional diffracting edges. However, relatively minor variations in geometry have sometimes been found to result in drastic changes to barrier performance. In this paper the Boundary Element Method is employed to calculate the sound field in the vicinity of complex barrier tops and sound field visualization techniques are used with these data to investigate how the sound field varies with frequency and dimensional changes. It is shown that for some top edge configurations local resonance effects have a significant effect on the attenuation afforded by the barrier.
Sclable Collaborative Virtual Environment Considering User's Interests Based on P2P Overlay Network
Authors: Yushi Nakai, Yoshitaka Shibata
Venue: Proceedings of the First International Conference on Complex, Intelligent and Software Intensive Systems (2007)

Recently, many applications of VR called Collaborative Virtual Environment (CVE) have been proposed and their cooperation methods by users and scalability issues to support a number of users have been investigated. However, by using conventional client/server model, the usability of co-operative works by users degreases and scalability in CVE cannot be attained as the number of the user increases. Also, in conventional CVE system, the presentation and interaction of 3D objects in CVE to users were simple, limited and did not consider the user's background such as user's interest and generation. Eventually the user satisfaction for CVE application was not necessarily enough. In order to overcome those difficulties, we introduce a new method which uses P2P overlay network to realize scalable CVE and recommendation system which uses user's interest to present and offer the proper objects in CVE. Using our suggested method, the 3D objects are distributed on the P2P overlay networks and their computing loads can be reduced, eventually the scalability of the CVE can be improved. Furthermore, by reflecting user interest information to the application system, user can access and communicate to 3D 2objects and contents in which he or she is more interested with higher priority. Thus, the total usability of the CVE system can be improved. In this paper, we propose a new CVE system using P2P overlay network and user recommendation system to reflect user's interest.
Image-based multi-view scene analysis using 'conexels'
Authors: Josep R. Casas, Jordi Salvador
Venue: Proceedings of the HCSNet workshop on Use of vision in human-computer interaction - Volume 56 (2006)

Multi-camera environments allow constructing volumetric models of the scene to improve the analysis performance of computer vision algorithms (e.g. disambiguating occlusion). When representing volumetric results of image-based multi-camera analysis, a direct approach is to scan the 3D space with regular voxels. Regular voxelization is good at high spatial resolutions for applications such as volume visualization and rendering of synthetic scenes generated by geometric models, or to represent data resulting from direct 3D data capture (e.g. MRI). However, regular voxelization shows a number of drawbacks for visual scene analysis, where direct measurements on 3D voxels are not usually available. In this case, voxel values are computed rather as a result of the analysis on 'projected' image data. In this paper, we first provide some statistics to show how voxels project to 'unbalanced' sets of image data in common multi-view analysis settings. Then, we propose a 3D geometry for multi-view scene analysis providing a better balance in terms of the number of pixels used to analyse each elementary volumetric unit. The proposed geometry is non-regular in 3D space, but becomes regular once projected onto camera images, adapting the sampling to the images. The aim is to better exploit multi-view image data by balancing its usage across multiple cameras instead of focusing in regular sampling of 3D space, from which we do not have direct measurements. An efficient recursive algorithm using the proposed geometry is outlined. Experimental results reflect better balance and higher accuracy for multi-view analysis than regular voxelization with equivalent restrictions.
Exact PDFs for sample covariance based array processors with elliptically contoured data
Authors: C. D. Richmond
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1996. on Conference Proceedings., 1996 IEEE International Conference - Volume 05 (1996)

Practical application of array processors typically requires the use of a sample covariance matrix (SCM). We add to the many results on SCM based (SCB) array processors by weakening the traditional assumption of data Gaussianity and subsequently providing for a class of array processors additional performance measures of value in practice. The snapshot data matrix is assumed complex multivariate elliptically contoured (MEC) distributed. The performance measures include the exact probability density functions (PDFs) and moments of the SCB weightings and beam responses of the following array processors: (1) maximum-likelihood signal vector estimator, (2) linearly constrained minimum variance beamformer (LCMV), (3) minimum variance distortionless response beamformer, and (4) generalized sidelobe canceller implementation of the LCMV beamformer. The SCB weightings for these array processors are complex multivariate standardized t-distributed and the SCB beam responses are generalized t. All results are completely invariant over the class of MECs considered. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Research Issues of Privacy Access Control Model for Mobile Ad Hoc Healthcare Applications with XACML
Authors: Patrick C. K. Hung, Jude Andrade, Yongming Chen, Ranny Huang, Miguel Vargas Martin, Yi Zheng
Venue: Proceedings of the 21st International Conference on Advanced Information Networking and Applications Workshops - Volume 02 (2007)

Information privacy is usually concerned with the confidentiality of protected health information (PHI) such as electronic medical records (EMR). To meet the needs of highly mobile patients in healthcare scenarios, mobile devices such as personal digital assistants (PDAs) are being used for storing entire patient histories and physicals, research data collection forms, the physician's reference desk, current care plans, and drug orders. Thus, the information access control mechanism for mobile ad hoc healthcare applications must be embedded with privacy-enhancing technologies. This paper presents the research issues of developing a privacy access control model for supporting mobile ad hoc healthcare applications. This paper also shows how eXtensible Access Control Markup Language (XACML) can protect confidential EMR in such a setting.
New alliances and continuing excellence
Authors: Jeffrey Popyack
Venue: ACM SIGCSE Bulletin (2007)

Greetings, and welcome again to Upsilon Pi Epsilon (UPE), the International Honor Society for the Computing and Information Disciplines. This year has seen some revisions in operating procedures, along with new chapters, a new alliance, and another bumper crop of awards to deserving students. Probably the most exciting of our changes is the hope of bringing a regular presence to the SIGCSE winter meeting. When the ACM Computer Science Conference (CSC) ceased its annual operation a decade ago, it left the International Computer Programming Contest (ICPC) and UPE National Meeting without a home. For many reasons, largely fiscal matters and UPE's role in founding the ICPC, the National Meeting has followed the ICPC. Unfortunately, with SIGCSE and ICPC strong enough to stand on their own without the former "Computing Week" umbrella, these activities eventually diverged, leaving us with very little connection to SIGCSE aside from an occasional booth, and of course this column. Fortunately, we are planning to test the waters at SIGCSE 2008, which should bring us together with our most natural constituency, computer science educators. See you there!
Robust adaptive beamforming in alpha-stable noise environments
Authors: P. Tsakalides
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1996. on Conference Proceedings., 1996 IEEE International Conference - Volume 05 (1996)

We develop an new adaptive beamforming technique based on fractional lower-order moment theory. The proposed adaptive beamformer adjusts the array response to a desired signal while discriminating against impulsive interference modeled as a stable process. Simulation results show that the new technique performs better in localizing a target both in space and Doppler, and thus offers the potential for improved airborne radar performance in space-time adaptive processing (STAP) applications.
Scalable automated methods for dynamic program analysis
Authors: Gul Agha
Venue:  (2006)

Testing using manually generated test cases is the primary technique used in industry to improve reliability of software---in fact, such ad hoc testing accounts for over half of the typical cost of software development. We propose new methods for systematically and automatically testing sequential and concurrent programs. The methods are based on three new techniques: concolic testing, race-detection and flipping, and predictive monitoring. Concolic testing combines concrete and symbolic testing to avoid redundant test cases as well as false warnings. Concolic testing can catch generic errors such as assertion violations, uncaught exceptions, and segmentation faults. Large real-world programs are almost always concurrent. Because of the inherent non-determinism of such programs, testing is notoriously hard. We extend concolic testing with a method called race-detection and flipping , which provides ways of reducing, often exponentially, the exploration space for concolic testing. This combined method provides the first technique to effectively test concurrent programs with complex data inputs. Concolic testing may also be combined with formal specifications by using runtime monitors. Runtime monitors are small software units which are synthesized automatically from the formal specification for the software and weaved into the code to dynamically check if the specification is violated. For multi-threaded concurrent programs, we developed a novel technique which allows efficient predictive monitoring to enable the detection of a violation by observing some related, but possibly bug free execution of a concurrent program. Predictive monitoring dramatically improves the efficiency of testing. Based on the above methods we have developed tools for testing both C and Java programs. We have used the tools to find bugs in several real-world software systems including SGLIB, a popular C data structure library used in a commercial tool, implementations of the Needham-Schroeder protocol and the TMN protocol, the scheduler of Honeywell's DEOS real-time operating system, and the Sum Microsystems' JDK 1.4 collection framework.
Does Interpersonal Trust Also Matter? Exploring the Role of Trust in Successful IT Outsourcing
Authors: Qi Cong, Patrick Y. K. Chau
Venue: Proceedings of the 40th Annual Hawaii International Conference on System Sciences (2007)

Recently, the focus of IT outsourcing has been shifting from the "what" and "why" issues to "how" companies manage outsourcing process, during which the relationship management becomes vitally important for the overall success of IT outsourcing. Simultaneously, trust, as a component of relationship, plays a central role in the success of IT outsourcing relationship. In view of these, this paper will explore the role of trust in successful relationship management, and further in the ultimate IT outsourcing success. The paper will also contribute by categorizing trust into two levels--organizational level and individual level, and exploring especially the effects of interpersonal trust. Knowledge sharing as a risk taking behavior will mediate the path from trust to relationship success. Theory of Organization Boundary Systems and Social Exchange Theory will be used in the model building process, and a survey will be conducted to test the model empirically.
Manipulating temporal dependencies in compressed video data with applications to compressed-domain processing of MPEG video
Authors: S. J. Wee
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 06 (1999)

The ability to manipulate the temporal dependencies in coded video data is important for a number of compressed domain video processing tasks. This paper formulates the general problem and examines it in the context of MPEG. This is used to develop a method for performing frame conversions in MPEG coded video data. These frame conversions are used to develop compressed-domain video processing algorithms for performing temporal mode conversion, frame-by-frame reverse play, and frame-accurate splicing.