ppxscal/embedding_network huggingface dataset:
Permuting Web Graphs
Authors: Paolo Boldi, Massimo Santini, Sebastiano Vigna
Venue: Proceedings of the 6th International Workshop on Algorithms and Models for the Web-Graph (2009)

Since the first investigations on web graph compression, it has been clear that the ordering of the nodes of the graph has a fundamental influence on the compression rate (usually expressed as the number of bits per link). The author of the LINK database [1], for instance, investigated three different approaches: an extrinsic ordering (URL ordering) and two intrinsic (or coordinate-free) orderings based on the rows of the adjacency matrix (lexicographic and Gray code); they concluded that URL ordering has many advantages in spite of a small penalty in compression. In this paper we approach this issue in a more systematic way, testing some old orderings and proposing some new ones. Our experiments are made in the WebGraph framework [2], and show that the compression technique and the structure of the graph can produce significantly different results. In particular, we show that for the transpose web graph URL ordering is significantly less effective, and that some new orderings combining host information and Gray/lexicographic orderings outperform all previous methods. In particular, in some large transposed graphs they yield the quite incredible compression rate of 1 bit per link.
SEP: A Space Efficient Pipelining Technique for Managing Disk Buffers in Multimedia Servers
Venue: Proceedings of the 1996 International Conference on Multimedia Computing and Systems (1996)

We present techniques for managing disks as a buffer for the tertiary storage of multimedia servers. A unified disk space is used to not only cache frequently referenced objects, but also to provide staging buffers for playing back objects. A new staging technique and three buffer replacement policies are investigated. The simulation results indicate that the staging method is very efficient, and each of the replacement policies offers significant additional improvement. Some of the performance issues are also analyzed analytically. The mathematical model provides guidelines for good multimedia systems design using the proposed techniques.
QuanTM: a quantitative trust management system
Authors: Andrew G. West, Adam J. Aviv, Jian Chang, Vinayak S. Prabhu, Matt Blaze, Sampath Kannan, Insup Lee, Jonathan M. Smith, Oleg Sokolsky
Venue: Proceedings of the Second European Workshop on System Security (2009)

Quantitative Trust Management (QTM) provides a dynamic interpretation of authorization policies for access control decisions based on upon evolving reputations of the entities involved. QuanTM, a QTM system, selectively combines elements from trust management and reputation management to create a novel method for policy evaluation. Trust management, while effective in managing access with delegated credentials (as in PolicyMaker and KeyNote), needs greater flexibility in handling situations of partial trust. Reputation management provides a means to quantify trust, but lacks delegation and policy enforcement. This paper reports on QuanTM's design decisions and novel policy evaluation procedure. A representation of quantified trust relationships, the trust dependency graph, and a sample QuanTM application specific to the KeyNote trust management language, are also proposed.
Performance estimation and slack matching for pipelined asynchronous architectures with choice
Authors: Gennette Gill, Vishal Gupta, Montek Singh
Venue: Proceedings of the 2008 IEEE/ACM International Conference on Computer-Aided Design (2008)

This paper presents a fast analytical method for estimating the throughput of pipelined asynchronous systems, and then applies that method to develop a fast solution to the problem of pipelining "slack matching." The approach targets systems with hierarchical topologies, which typically result when high-level (block structured) language specifications are compiled into data-driven circuit implementations. A significant contribution is that our approach is the first to efficiently handle architectures with choice (i.e., the presence of conditional computation constructs such if-then-else and conditional loops). The key idea behind the fast speed of our analysis method is to exploit information about the hierarchy of a given block-structured system, thereby yielding a runtime that is linear in the number of pipeline stages. In contrast, existing approaches typically represent an entire system as a single Petri net or marked graph, and then apply Markov chain analysis or other state enumeration methods with costly runtimes. Building upon our analysis approach, we introduce a novel solution to the problem of slack matching, i.e., determining optimal insertion of FIFO stages into a pipelined design to improve performance. We present both an optimal solution using an MILP formulation, and a fast heuristic algorithm that yielded optimal results for all of our examples.
Thread-Based Competitive Or-Parallelism
Authors: Paulo Moura, Ricardo Rocha, Sara C. Madeira
Venue: Proceedings of the 24th International Conference on Logic Programming (2008)

This paper presents the logic programming concept of thread-based competitive or-parallelism, which combines the original idea of competitive or-parallelism with committed-choice nondeterminism and speculative threading. In thread-based competitive or-parallelism, an explicit disjunction of subgoals is interpreted as a set of concurrent alternatives, each running in its own thread. The subgoals compete for providing an answer and the first successful subgoal leads to the termination of the remaining ones. We discuss the implementation of competitive or-parallelism in the context of Logtalk, an object-oriented logic programming language, and present experimental results.
A Probability Model for Projective Clustering on High Dimensional Data
Authors: Lifei Chen, Qingshan Jiang, Shengrui Wang
Venue: Proceedings of the 2008 Eighth IEEE International Conference on Data Mining (2008)

Clustering high dimensional data is a big challenge in data mining due to the curse of dimensionality. To solve this problem, projective clustering has been defined as an extension of traditional clustering that seeks to find projected clusters in subsets of dimensions of a data space. In this paper, the problem of modeling projected clusters is first discussed, and an extended Gaussian model is proposed. Second, a general objective criterion used with $k$-means type projective clustering is presented based on the model. Finally, the expressions to learn model parameters are derived and then used in a new algorithm named FPC to perform fuzzy clustering on high dimensional data. The experimental results on document clustering show the effectiveness of the proposed clustering model.
A Novel Algorithm Applied to Task Scheduling in Grid Computing
Authors: Wei Wang, Daisheng Luo, Wanneng Shu, Yong Fang
Venue: International Journal of Distributed Sensor Networks (2009)

In this paper a novel optimal scheduling model and its algorithm are developed for task scheduling problems. A novel annealing-inspired genetic algorithm is applied to solve the scheduling model. The effectiveness of the algorithm is shown for a number of test problems and performance comparisons with the genetic algorithm, simulated annealing are also discussed.
The Measurement of Additional Secondary Factor Based on Integrated Longwave and Microwave Navigation System
Authors: Huang Ying
Venue: Proceedings of the 2009 International Conference on Electronic Computer Technology (2009)

The modification of the longwave ASF (Additional Secondary Factor) is the key to ensure the precision of longwave navigation system, but at present there does not exist the effective way to measure the ASF, because of the effect of the geography. So the paper put forward the way that can measure the ASF, resulted from the theory of wavelet and least square, based on the integrated longwave and microwave navigation system. Meantime, the paper used the way to practical experiment, which proves it effective. And the usage of that method can combine our country navigation sources, improved the ability of our positioning.
Multi-target Tracking in Wireless Sensor Networks Using Distributed Joint Probabilistic Data Association and Average Consensus Filter
Authors: M. A. Tinati, T. Yousefi Rezaii
Venue: Proceedings of the 2009 International Conference on Advanced Computer Control (2009)

The aim of this paper is to develop a distributed Multi-Target Tracking (MTT) algorithm over wireless sensor networks which has the ability of online implementation in low-cost sensor nodes due to its lower computational complexity and execution time compared to the other MTT systems. The Monte Carlo (MC) implementation of JPDAF (MC-JPDAF) is applied to the classical problem of TT in a cluttered area. Also, to make the tracking algorithm scalable and usable for large networks, the distributed Expectation Maximization (EM) algorithm is used via the average consensus filter in order to diffuse the nodes’ information over the whole network. Furthermore, some simplifications and modifications are made to MC-JPDAF algorithm in order to reduce the computation complexity of the tracking system and make it suitable for low-energy sensor networks. Finally, the simulations of tracking tasks for the proposed system are given.
Design and Evaluation of DNS as Location Manager for HIP
Authors: Shuigen Yang, Hongbin Luo, Yajuan Qin, Hongke Zhang
Venue: Wireless Personal Communications: An International Journal (2009)

Host Identity Protocol (HIP) is designed to provide secure and continuous communication by separating the identifier and locator roles of the Internet Protocol (IP) address. HIP also has efficient solutions to support host mobility. In this paper, we propose a location management scheme based on Domain Name System (DNS) for HIP. In the proposed scheme, a new DNS HIP resource record is used to translate a domain name into a host identity tag and an IP address. We also develop an analytical model to study the performance of DNS as location manager in terms of success rate, which takes into account the velocity of mobile nodes, the radius of a subnet, the regional network size, the packet transmission delay between the mobile node and the rendezvous server, and the packet processing delay at the DNS and the rendezvous server. The performance results show that for a reasonable range, the DNS is a feasible solution for location management with high success rate for HIP.
Non-linear volume photon mapping
Authors: Diego Gutierrez, Adolfo Munoz, Oscar Anson, Francisco J. Seron
Venue: ACM SIGGRAPH ASIA 2008 courses (2008)

This paper describes a novel extension of the photon mapping algorithm, capable of handling both volume multiple inelastic scattering and curved light paths simultaneously. The extension is based on the Full Radiative Transfer Equation (FRTE) and Fermat's law, and yields physically accurate, high-dynamic data than can be used for image generation or for other simulation purposes, such as driving simulators, underwater vision or lighting studies in architecture. Photons are traced into the participating medium with a varying index of refraction, and their curved trajectories followed (curved paths are the cause of certain atmospheric effects such as mirages or rippling desert images). Every time a photon is absorbed, a Russian roulette algorithm based on the quantum efficiency of the medium determines whether the inelastic scattering event takes place (causing volume fluorescence). The simulation of both underwater and atmospheric effects is shown, providing a global illumination solution without the restrictions of previous approaches.
MR-MIL: Manifold Ranking Based Multiple-Instance Learning for Automatic Image Annotation
Authors: Yufeng Zhao, Yao Zhao, Zhenfeng Zhu, Jeng-Shyang Pan
Venue: IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (2008)

A novel automatic image annotation (AIA) scheme is proposed based on multiple-instance learning (MIL). For a given concept, manifold ranking (MR) is first employed to MIL (referred as MR-MIL) for effectively mining the positive instances (i.e. regions in images) embedded in the positive bags (i.e. images). With the mined positive instances, the semantic model of the concept is built by the probabilistic output of SVM classifier. The experimental results reveal that high annotation accuracy can be achieved at region-level.
Architectural support for SWAR text processing with parallel bit streams: the inductive doubling principle
Authors: Robert D. Cameron, Dan Lin
Venue: Proceeding of the 14th international conference on Architectural support for programming languages and operating systems (2009)

Parallel bit stream algorithms exploit the SWAR (SIMD within a register) capabilities of commodity processors in high-performance text processing applications such as UTF-8 to UTF-16 transcoding, XML parsing, string search and regular expression matching. Direct architectural support for these algorithms in future SWAR instruction sets could further increase performance as well as simplifying the programming task. A set of simple SWAR instruction set extensions are proposed for this purpose based on the principle of systematic support for inductive doubling as an algorithmic technique. These extensions are shown to significantly reduce instruction count in core parallel bit stream algorithms, often providing a 3X or better improvement. The extensions are also shown to be useful for SWAR programming in other application areas, including providing a systematic treatment for horizontal operations. An implementation model for these extensions involves relatively simple circuitry added to the operand fetch components in a pipelined processor.
First hyperpolarizability of donor-acceptor substituted aromatic backbone molecular systems: Effect of dihedral angle and excitation energy
Authors: Diksha Makwani, R. Vijaya
Venue: Journal of Computational Methods in Sciences and Engineering (2008)

Charge transfer molecular systems that contain two fused benzene rings as the core have been studied for their contribution to the first order hyperpolarizability &beta;. Two identical donor groups are attached through the core to two cyanide groups that act as acceptors. Calculation of &beta; has been done using ab-initio HF and semi-empirical AM1 Hamiltonian. The effect of twist (dihedral) angle &thgr; on &beta; and HOMO-LUMO energy gap has been analyzed using both the methods. Inverse relationship between HOMO-LUMO energy gap and &beta; is observed from their variation with the dihedral angle only in the case of AM1. It is clear from the study that a planar geometry is not an essential condition for a large value of &beta;. Dispersion plots show the first excitation energy values for all the molecules using AM1 and HF/6-31+G(d,p). These plots show a dip in the first excitation peak for AM1. This feature is also observed in the frequency-dependent &beta; calculated by the same method for the equivalent single-core molecules. The first excitation energy values with AM1 calculations are comparable to HF/6-31G(d) but different from HF/6-31+G(d,p). However, the calculation of &beta; using ab-initio Hartree-Fock method does not show the double peak feature, thus providing a clue about the robustness of the model and the influence of basis set in calculating &beta;.
Cross-View Object Tracking by Projective Invariants and Feature Matching
Authors: Ning Ouyang, Le-Ping Lin, Zhao Liu
Venue: Proceedings of the 9th Pacific Rim Conference on Multimedia: Advances in Multimedia Information Processing (2008)

One of the key techniques of multi-camera tracking systems is cross-view object tracking. Feature Matching (FM) and Field of View (FOV) based methods are adopted in conventional solutions towards this problem. However, FM is not computationally efficient and the results heavily depend on the parameter settings of the cameras. Therefore, it is not effective in practical applications. In addition, approaches based on FOV suffer from the delay of the detection of newly appeared objects. The results are not reliable if only consistent labelling is utilized. In this paper, we propose a novel scheme for cross-view object tracking based on Projective Invariants (PI) and FM. The experimental results show that, our method improves the performance of normal PI-based tracking algorithms. Especially, it provides accurate tracking performance in the case of multiple objects appear closely in the same area.
A Replication-Aware CDN-P2P Architecture Based on Two-Step Server Selection and Network Coding
Authors: Hung-Chang Yang, Min-Yi Hsieh, Hsiang-Fu Yu, Li-Ming Tseng
Venue: Proceedings of the 9th Pacific Rim Conference on Multimedia: Advances in Multimedia Information Processing (2008)

E-learning service is getting increasingly popular, especially the multimedia content educations. To distribute content to end users, two different technologies --- Content Distribution Network (CDN) and Peer-to-Peer (P2P) network --- have been proposed. However, both technologies have their own limitations: CDN servers are expensive to deploy and maintain. Under P2P network, anyone could share his content regardless of the copyright. In this paper, a new concept of integrating both CDN and P2P technologies into a replication-aware CDN-P2P architecture has been proposed. We propose a two-step selection approach on landmark-based selection algorithm to find the nearest replica-cache server and peer-caches to download content in this architecture. Furthermore, recent studies have supported the claim that network coding technology is beneficial for large-scale P2P content distribution. Herein, we show how to apply network coding technology to distribute content so that the content provider's rights can be protected.
H.264-based Multiple Security Levels Net Video Encryption Scheme
Authors: Yan Li, Main Cai
Venue: Proceedings of the 2009 International Conference on Electronic Computer Technology (2009)

Due to traditional and single video encryption algorithms can’t meet the needs of various net multimedia services. This paper references the H.264 video coding standard and video encryption algorithms, analyzes the existing video encryption algorithms from security, speed, compression ratio and date operability, and classes the video encryption algorithms according to security. It also proposes the multiple security levels net video encryption scheme. The scheme could meet requirements of different net videos, provide safe and real-time services, improve the utilization of net resources, and have a good adaptation to network.
An implementation of the SANE Virtual Processor using POSIX threads
Authors: M. W. van Tol, C. R. Jesshope, M. Lankamp, S. Polstra
Venue: Journal of Systems Architecture: the EUROMICRO Journal (2009)

The SANE Virtual Processor (SVP) is an abstract concurrent programming model that is both deadlock free and supports efficient implementation. It is captured by the @mTC programming language. The work presented in this paper covers a portable implementation of this model as a C++ library on top of POSIX threads. Programs in @mTC can be translated to the standard C++ syntax and linked with this library to run on conventional systems. The motivation for this work was to provide an early implementation on conventional processors as well as supporting work from programming FPGA chips to Grids.
Parts-based segmentation with overlapping part models using Markov chain Monte Carlo
Authors: Matthias Seise, Stephen J. McKenna, Ian W. Ricketts, Carlos A. Wigderowitz
Venue: Image and Vision Computing (2009)

A probabilistic method is proposed for segmenting multiple objects that overlap or are in close proximity to one another. A likelihood function is formulated that explicitly models overlapping object appearance. Priors on global appearance and geometry (including shape) are learned from example images. Markov chain Monte Carlo methods are used to obtain samples from a posterior distribution over model parameters from which expectations can be estimated. The method is described in detail for the problem of segmenting femur and tibia in X-ray images. The result is a probabilistic segmentation that quantifies uncertainty, conditioned upon the model, so that measurements such as joint space can be made with associated uncertainty.
From technology prototypes to ethnographic studies: a look to the Ubicomp research directions
Authors: Petteri Alahuhta, Heikki Ailisto
Venue: Proceedings of the International Conference on Mobile Technology, Applications, and Systems (2008)

In this paper, the accepted submissions published on Handheld and Ubiquitous computing (HUC) and Ubicomp conferences between 1999 and 2007 are reviewed. We classify 244 papers into six distinct categories and analyze the change in the distribution of the papers in these categories over the period under review. The strongest change trends identified in the analysis are the decrease of number of application and interaction related papers and the increase of number of user studies. Furthermore, we recognized three major issues that we think are missing in the reviewed research: Internet-related research, research on technology adaptation and acceptance among end users, as well as reports on the large-scale deployment of ubiquitous systems. We describe the state of the art in ubiquitous computing in the sense of design space as defined by Stankiewitz. In this regard the field has evolved from technological prototyping oriented art towards end user-driven approaches where real world constraints are taken more seriously. A need for future work on user acceptance, interoperability and privacy issues is suggested.
Stochastic π-Calculus Modelling of Multisite Phosphorylation Based Signaling: The PHO Pathway in Saccharomyces Cerevisiae
Authors: Nicola Segata, Enrico Blanzieri
Venue: Transactions on Computational Systems Biology X (2008)

We propose a stochastic &pi;-calculus modelling approach able to handle the complexity of post-translational signalling and to overcome some limitations of the ordinary differential equations based methods. The model we developed is customizable without a priori assumptions to every multisite phosphorylation regulation. We applied it to the multisite phosphorylation of the Pho4 transcription factor that plays a crucial role in the phosphate starvation signalling in Saccharomyces cerevisiae, using available in vitro experiments for the model tuning and validation. The in silico simulation of the sub-path with the stochastic &pi;-calculus allows quantitative analyses of the kinetic characteristics of the Pho4 phosphorylation, the different phosphorylation dynamics for each site (possibly combined) and the variation of the kinase activity as the reaction goes to completion. One of the predictions indicates that the Pho80-Pho85 kinase activity on the Pho4 substrate is nearly distributive and not semi-processive as previously found analysing only the phosphoform concentrations in vitro. Thanks to the compositionality property of process algebras, we also developed the whole PHO pathway model that gives new suggestions and confirmations about its general behaviour. The potentialities of process calculi-based in silico simulations for biological systems are highlighted and discussed.