ppxscal/embedding_network huggingface dataset:
Graph-theoretic analysis of structured peer-to-peer systems: routing distances and fault resilience
Authors: Dmitri Loguinov, Juan Casas, Xiaoming Wang
Venue: IEEE/ACM Transactions on Networking (TON) (2005)

This paper examines graph-theoretic properties of existing peer-to-peer networks and proposes a new infrastructure based on optimal-diameter de Bruijn graphs. Since generalized de Bruijn graphs exhibit very short average distances and high resilience to node failure, they are well suited for distributed hash tables (DHTs). Using the example of Chord, CAN, and de Bruijn, we study the routing performance, graph expansion, clustering properties, and bisection width of each graph. Having confirmed that de Bruijn graphs offer the best diameter and highest connectivity among the existing peer-to-peer structures, we offer a very simple incremental building process that preserves optimal properties of de Bruijn graphs under uniform user joins/departures. We call the combined peer-to-peer architecture optimal diameter routing infrastructure.
Linear State Space Feedforward and Feedback Structures for Blind Source Recovery in Dynamic Environments
Authors: Khurram Waheed, Fathi M. Salem
Venue: Neural Processing Letters (2005)

Blind Source Recovery (BSR) denotes recovery of original sources or signals from environments, which may include convolution, temporal variation, and even non-linearity--without necessarily performing explicit environment identification. This paper presents two separate multiple-input multiple-output (MIMO) structures for dynamic linear Blind Source Recovery (BSR) of multiple stochastically independent source signals. We propose linear state space models for both the mixing environment and the demixing (or the recovering) adaptive network. The demixing network may assume either the feedforward or the feedback state space configuration. Separate algorithms have been derived for the adaptive estimation of the feedforward and the feedback demixing/recovering network's parameters. These algorithms are based on the multivariable optimization theory and utilize the Riemannian contra-variant gradient (or the natural gradient) search under the constraints of a state space representation. Auxiliary conditions for the convergence of these algorithms have also been derived and discussed. Illustrative simulation examples have been included to demonstrate the successful adaptation results for both proposed demixing network structures in the case of an infinite impulse response (IIR)-type mixing environment for example source statistical distributions.
Scaling Behavior of Internet Packet Delay Dynamics Based on Small-interval Measurements
Authors: Kai Wang, Jing Huang, Zhongcheng Li, Xiaohong Wang, Feng Yang, Jingping Bi
Venue: Proceedings of the The IEEE Conference on Local Computer Networks 30th Anniversary (2005)

Packet delay is one of the most important Internet performance metrics. Many studies indicate that long-range dependence (LRD) exits in Internet packet delay, but the scaling behavior of packet delay is very complicated. This paper analyzes the Internet round-trip time (RTT) behavior based on small-interval (10ms) measurements and finds that RTT series consist of two completely different components: spiky component and normal component. A bottleneck model is proposed to explain the phenomenon. By using detrended fluctuation analysis (DFA) method, it is found that the original RTT series don't exhibit simplex scaling behavior, and although the spiky component accounts for a little proportion of the original RTT series, it has a great impact on the scaling behavior. After removing the spiky component, RTT series show LRD, with Hurst exponent ranging from 0.55 to 0.8.
S-shaped TCP: A new transport protocol for fast long-distance networ
Authors: Masayoshi Nabeshima
Venue: Proceedings of the The IEEE Conference on Local Computer Networks 30th Anniversary (2005)

It is well known that TCP does not fully utilize the available bandwidth in fast long-distance networks. To solve this scalability problem, this paper proposes S-shaped TCP (SSTCP). The window growth function of SS-TCP is, in the steady state, S-shaped, and it can be divided into three regions. In region I, the window growth rate of SS-TCP is the same as that of standard TCP (STD-TCP). In region II, the window of SS-TCP grows faster than that of STD-TCP. In region III, SS-TCP decreases its window growth rate as the network is becoming congested. 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
A Developmental View of System Security
Authors: Christopher L. Huntley
Venue: Computer (2006)

Security should be integrated into an organization in such a way that it enhances and safeguards each facet in the least intrusive yet most effective way possible at any given time.
Large Empirical Case Study of Architecture-Based Software Reliability
Authors: Katerina Goseva-Popstojanova, Margaret Hamill, Ranganath Perugupalli
Venue: Proceedings of the 16th IEEE International Symposium on Software Reliability Engineering (2005)

In this paper we present an empirical study of architecture-basedsoftware reliability based on a large open source application which consists of 350,000 lines of C code. The goals of our study are to analyze empirically the adequacy, applicability, and accuracy of architecture-based software reliability models. For this purpose we developed innovative approaches to efficiently extract and more accurately analyze a large amount of empirical data. Applying the theoretical results on a large scale field study allows us to test how and when they work, to understand their limitations, and outline the issues that need attention in the future research studies. Thus, our results show that for a subset of failures which can clearly be attributed to single components, both the composite and hierarchical models are very accurate when compared to the actual reliability. However, the assumptions made by the existing architecture-based software reliability models do not allow to account for the remaining failures which led to fixing faults in multiple components. These results show that in order to progress further, software reliability engineering should go through cycles of building models, testing them empirically, learning from the experiments, and refining the models to capture the newly discovered phenomena.
A Compiler-Controlled Instruction Cache Architecture for an Embedded Low Power Microprocessor
Authors: Xiaoping Zhu, Teng Tiow Tay
Venue: Proceedings of the The Fifth International Conference on Computer and Information Technology (2005)

Modern microprocessors have been improving their performance with deeper sub-micron technologies and larger on-chip cache memories. This trend leads to a dramatic increment of power consumption in such units and has prompted researchers to develop power efficient caches. Here we propose a method that dynamically turns off those unused cache lines to save power at architecture level. In our algorithm, the object codes of programs are reallocated in memory address map so that the working sets are reduced when they are loaded into I-cache. In addition, a few special cache-scaling instructions (CSIs) are added to the object codes to track the working set sizes. With the information from CSIs and the current system state, a hardware controller implements the decision of caching instructions and scales the size of cache memory. Experimental results using popular Windowsbased applications show that the compiler-controlled resizable cache can reduce 55.8% of energy in a 32K I-cache with only 2.9% of performance degradation on average.
Range of motion estimation from Mocap data
Authors: Hiroshi Yasuda, Suguru Saito, Masayuki Nakajima
Venue: Proceedings of the 2005 International Conference on Cyberworlds (2005)

In this paper, we propose a novel technique to estimate joint ROM (Range of motion) from Mocap (Motion capture) data. For each joint, the probability density function of joint angle is estimated by Mixture of Gaussian, and the angle space is divided into Voronoi cells which have a kernel of Gaussian at these centers. Then, the sets of the Voronoi cells in two different joints, which occur in the Mocap data, are used to approximate the ROM taking into account the change related to the angle of the other joint. As all of this estimation processes are performed on the simple ball joint model, we do not need to introduce any complex musculo-skeletal model. Our method can also estimate the ROMs even for the joints which have difficulty to measure the angle directly by physical measurement as well as the joints of limbs.
Moving Mesh Finite Element Methods for an Optimal Control Problem for the Advection-Diffusion Equation
Authors: Konstantinos Chrysafinos
Venue: Journal of Scientific Computing (2005)

An optimal control problem for the advection-diffusion equation is studied using a Lagrangian-moving mesh finite element method. The weak formulation of the model advection---diffusion equation is based on Lagrangian coordinates, and semi---discrete (in space) error estimates are derived under minimal regularity assumptions. In addition, using these estimates and Brezzi-Rappaz-Raviart theory, symmetric error estimates for the optimality system are derived. The results also apply for advection dominated problems
Advanced MythTV video processing
Authors: Matthew Gast
Venue: Linux Journal (2005)

Once you've got MythTV set up, how do you extract video so you can watch it on other devices?
Motion Recovery by Integrating over the Joint Image Manifold
Authors: Liran Goshen, Ilan Shimshoni, P. Anandan, Daniel Keren
Venue: International Journal of Computer Vision (2005)

Recovery of epipolar geometry is a fundamental problem in computer vision. The introduction of the "joint image manifold" (JIM) allows to treat the recovery of camera motion and epipolar geometry as the problem of fitting a manifold to the data measured in a stereo pair. The manifold has a singularity and boundary, therefore special care must be taken when fitting it.Four fitting methods are discussed--direct, algebraic, geometric, and the integrated maximum likelihood (IML) based method. The first three methods are the exact analogues of three common methods for recovering epipolar geometry. The more recently introduced IML method seeks the manifold which has the highest "support," in the sense that the largest measure of its points are close to the data. While computationally more intensive than the other methods, its results are better in some scenarios. Both simulations and experiments suggest that the advantages of IML manifold fitting carry over to the task of recovering epipolar geometry, especially when the extent of the data and/or the motion are small.
Generation of tree movement sound effects: Research Articles
Authors: Katsutsugu Matsuyama
Venue: Computer Animation and Virtual Worlds (2005)

This paper presents a method for automatically generating sound effects for an animation of branches and leaves moving in the wind. Each tree is divided into branches and leaves, and an independent sound effect generation process is employed for each element. The individual results are then compounded into one sound effect. For the branches, we employ an approach based on the frequencies of experimentally obtained Karman vortex streets. For the leaves, we use the leaf blade state as the input and assume a virtual musical instrument that uses wave tables as the sound source. All computations can be performed independently for each frame step. Therefore, each frame step can be executed on completion of the animation step. The results of the implementation of the approach are presented and it is shown that the process offers the possibility of real-time operation through the use of parallel computing techniques. Copyright &copy; 2005 John Wiley & Sons, Ltd.
Model representation with aesthetic computing: Method and empirical study
Authors: Paul Fishwick, Timothy Davis, Jane Douglas
Venue: ACM Transactions on Modeling and Computer Simulation (TOMACS) (2005)

We define a new methodology, aesthetic computing, for customizing discrete structures found in mathematics, programming, and computer simulation. The methodology is presented as a procedure, defined within the context of the semantic web, involving a successive chain of model transformations from a source model to a target model, with the source model being the discrete structure to represent and the target model being the geometric model. We also present an implementation based on this methodology, and a class where empirical studies were performed to assess student perceptions on how customized model structures affected their understanding and preferences regarding visual and interactive model representations. Students appear to prefer the methodology as a way to inject creativity into model building, and to allow them to explore alternative, analogical representations influenced by the fields of aesthetics and the arts.
Effect of Antenna Beam Pattern and Layout on Cellular Performance in High Altitude Platform Communications
Authors: J. Thornton, D. A. Pearce, D. Grace, M. Oodo, K. Katzis, T. C. Tozer
Venue: Wireless Personal Communications: An International Journal (2005)

High Altitude Platforms may offer high spectrum efficiency by deploying multi-beam, multi-cell communications networks. The properties of the antennas carried by the HAP payload are key to the effective exploitation of these benefits. This paper compares different models for the antenna sidelobe region and quantifies, in each case, the carrier to interference ratio for a 3 channel re-use plan. Networks of 121 and 313 cells are compared. We show how the ITU recommended pattern for the 47/48 GHz band leads to pessimistic results compared to an adapted pattern which fits that of measured data for an elliptic beam lens antenna. The method is then extended to consider other radiation patterns. Spectrum sharing issues are explored with reference to further ITU recommendations and comparison with measurement data. Finally, an ITU type cellular layout which uses the same antenna for each cell is compared to an alternative hexagonal layout where each cell has equal size.
Descriptional complexity of block-synchronization context-free grammars
Authors: Ian McQuillan
Venue: Journal of Automata, Languages and Combinatorics (2004)

We consider the descriptional complexity of block-synchronization context-free grammars, BSCF grammars. In particular, we consider the number of necessary situation and begin symbols as complexity measures. For weak and strong derivations, one begin symbol and two situation symbols are sufficient to generate all respective language families. Surprisingly, one situation symbol with equality synchronization is also sufficient to generate all weak derivation BSCF languages. The family of synchronized context-free languages (SCF languages) generated by grammars with one situation symbol using equality synchronization gives a language family properly between that of E0L and ET0L languages. Some normal forms are also presented for all variations. In addition, we show that either prefix or equality synchronization can be used to describe all weak and strong derivation languages.
Simulated demand in large-scale batch processing acquisitions: role and justification
Authors: Ross T. Newkirk, James K. Mullin
Venue: ACM SIGSIM Simulation Digest (1974)

The authors present this paper in the context of a successful acquisition of a multi user large scale batch processing system. They discuss the role of simulated demand (a) in determining basic system requirements, (b) as the major part of system specifications made available to vendors and (c) as a major tool in system testing and evaluation.They discuss the simulation of demand profiles from statistical records and user interviews and how this led to specifying minimum system requirements. The integration of simulated demand in formal system specifications is detailed. In particular, the assembly of an adequate test package to permit vendors to provide meaningful responses with their proposals is of interest. The authors show how an extensive series of benchmark programs and kernel routines were assembled to test adequately total system performance under various combinations. The evaluation process in terms of performance graphs in light of the initial specifications is reviewed.In summary, the authors discuss the results of specification, evaluation, selection and installation process in light of system suitability experienced after an initial period of use.
Overlay multicast for real-time distributed simulation
Authors: Dennis M. Moen
Venue:  (2005)

This dissertation is an investigation of overlay multicast services in support of distributed real-time virtual simulations over an open network environment. Overlay multicasting provides message relay services to support many-to-many communications in the very dynamic environment of distributed real-time virtual simulation. This dissertation demonstrates that overlay multicast services is a viable mechanism to meet the demands of communications messaging far distributed real-time virtual simulation. A message traffic generator and test environment was developed for use in performance evaluation of a prototype protocol used to demonstrate feasibility far use of overlay multicast to support distributed real-time simulation. An analytical model was developed to represent the message flow characteristics to determine the regions of feasibility for performance for overlay multicasting to support the target application environment. The analytical model was validated in laboratory measurements of the prototype and the results used to influence the design of the overlay protocol architecture. Studies were conducted of live real-time distributed simulations operating in the laboratory and over the Defense Research and Engineering Network (DREN). Detailed studies and analysis of simulations in the laboratory were also conducted to help characterize the operating system performance that might be required to host the overlay protocol. A proposed top-level architecture for the overlay protocol was developed based on key concepts identified in the laboratory performance studies, the analytical model, and the studies of live simulations. The proposed protocol is called the Extensible Modeling and Simulation Framework Overlay Multicast Protocol (XOM).
Clustering spatial data with a hybrid EM approach
Authors: Tianming Hu, Yuan Sung
Venue: Pattern Analysis Applications (2005)

In spatial clustering, in addition to the object similarity in the normal attribute space, similarity in the spatial space needs to be considered and objects assigned to the same cluster should usually be close to one another in the spatial space. The conventional expectation maximization (EM) algorithm is not suited for spatial clustering because it does not consider spatial information. Although neighborhood EM (NEM) algorithm incorporates a spatial penalty term to the criterion function, it involves much more iterations in every E-step. In this paper, we propose a Hybrid EM (HEM) approach that combines EM and NEM. Its computational complexity for every pass is between EM and NEM. Experiments also show that its clustering quality is better than EM and comparable to NEM.
Key distribution and update for secure inter-group multicast communication
Authors: Weichao Wang, Bharat Bhargava
Venue: Proceedings of the 3rd ACM workshop on Security of ad hoc and sensor networks (2005)

Group communication has become an important component in wireless networks. In this paper, we focus on the environments in which multiple groups coexist in the system, and both intra and inter group multicast traffic must be protected by secret keys. We propose a mechanism that integrates polynomials with flat tables to achieve personal key share distribution and efficient key refreshment during group changes. The proposed mechanism distributes keys via true broadcast. The contributions of the research include: (1) By switching from asymmetric algorithms to symmetric encryption methods, the proposed mechanism avoids heavy computation, and improves the processing efficiency of multicast traffic and the power usage at the wireless nodes. The group managers do not have to generate public-private key pairs when the group member changes. (2) It becomes more difficult for an attacker to impersonate another node since personal key shares are adopted. The additional storage overhead at the wireless nodes and the increased broadcast traffic during key refreshment are justified. In addition, we describe techniques to improve the robustness of the proposed mechanism under the complicated scenarios such as collusive attacks and batch group member changes.
LU-GPU: Efficient Algorithms for Solving Dense Linear Systems on Graphics Hardware
Authors: Nico Galoppo, Naga K. Govindaraju, Michael Henson, Dinesh Manocha
Venue: Proceedings of the 2005 ACM/IEEE conference on Supercomputing (2005)

We present a novel algorithm to solve dense linear systems using graphics processors (GPUs). We reduce matrix decomposition and row operations to a series of rasterization problems on the GPU. These include new techniques for streaming index pairs, swapping rows and columns and parallelizing the computation to utilize multiple vertex and fragment processors. We also use appropriate data representations to match the rasterization order and cache technology of graphics processors. We have implemented our algorithm on different GPUs and compared the performance with optimized CPU implementations. In particular, our implementation on a NVIDIA GeForce 7800 GPU outperforms a CPU-based ATLAS implementation. Moreover, our results show that our algorithm is cache and bandwidth efficient and scales well with the number of fragment processors within the GPU and the core GPU clock rate. We use our algorithm for fluid flow simulation and demonstrate that the commodity GPU is a useful co-processor for many scientific applications.
Automatic Extraction of Ground-Glass Opacity Shadows on CT Images of the Thorax by Correlation between Successive Slices
Authors: Hyoungseop Kim, Masaki Maekado, Joo Kooi Tan, Seiji Ishikawa, Masaaki Tsukuda
Venue: Proceedings of the 17th IEEE International Conference on Tools with Artificial Intelligence (2005)

In general, segmentation is difficult because surrounding soft tissues and organs have similar CT values and sometimes contact with each other. We propose a new technique for automatic segmentation of lung regions and its classification for ground-glass opacity from the segmented lung regions by computer based on a set of the thorax CT images. In this paper, we segment the lung region for extraction of the region of interest employing binarization and labeling process from the inputted each slices images. The region having the largest area is regarded as the tentative lung regions. Furthermore, the ground-glass opacity is classified by correlation distribution on the slice to slice from the extracted lung region with respect to the thorax CT images. Experiment is performed employing twenty six thorax CT image sets and 96% of recognition rates were achieved. Obtained results are shown along with a discussion.
Tools and techniques for improving the efficiency of federal automatic data processing operations
Authors: Harold Joseph Highland
Venue: ACM SIGSIM Simulation Digest (1974)

Because of numerous members interested in the simulation of computer systems, I have included this note about a new volume issued by the GAO (General Accounting Office). This 44-page document was prepared last winter and resulted in the formation of a CPE office within the GSA (General Services Administration). 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