ppxscal/embedding_network huggingface dataset:
Stability analysis of biorthogonal multiwavelets whose duals are not in L2 and its application to local semiorthogonal lifting
Authors: Jan Maes, Adhemar Bultheel
Venue: Applied Numerical Mathematics (2008)

Wavelets have been used in a broad range of applications such as image processing, computer graphics and numerical analysis. The lifting scheme provides an easy way to construct wavelet bases on meshes of arbitrary topological type. In this paper we shall investigate the Riesz stability of compactly supported (multi-) wavelet bases that are constructed with the lifting scheme on regularly refined meshes of arbitrary topological type. More particularly we are interested in the Riesz stability of a standard two-step lifted wavelet transform consisting of one prediction step and one update step. The design of the update step is based on stability considerations and can be described as local semiorthogonalization, which is the approach of Lounsbery et al. in their groundbreaking paper [M. Lounsbery, T.D. DeRose, J. Warren, Multiresolution analysis for surfaces of arbitrary topological type, ACM Trans. Graphics 16 (1) (1997) 34-73]. Riesz stability is important for several wavelet based numerical algorithms such as compression or Galerkin discretization of variational elliptic problems. In order to compute the exact range of Sobolev exponents for which the wavelets form a Riesz basis one needs to determine the smoothness of the dual system. It might occur that the duals, that are only defined through a refinement relation, do not exist in L"2. By using Fourier techniques we can estimate the range of Sobolev exponents for which the wavelet basis forms a Riesz basis without explicitly using the dual functions. Several examples in one and two dimensions are presented. These examples show that the lifted wavelets are a Riesz basis for a larger range of Sobolev exponents than the corresponding non-updated hierarchical bases but, in general, they do not form a Riesz basis of L"2.
Boundedness of the Domain of Definition is Undecidable for Polynomial ODEs
Authors: Daniel S. Graça, Jorge Buescu, Manuel L. Campagnolo
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2008)

Consider the initial-value problem with computable parameters{dxdt=p(t,x)x(t"0)=x"0, where p:R^n^+^1->R^n is a vector of polynomials and (t"0,x"0)@?R^n^+^1. We show that the problem of determining whether the maximal interval of definition of this initial-value problem is bounded or not is in general undecidable.
Scheduling considerations for building dynamic verification tools for MPI
Authors: Sarvani Vakkalanka, Michael DeLisi, Ganesh Gopalakrishnan, Robert M. Kirby
Venue: Proceedings of the 6th workshop on Parallel and distributed systems: testing, analysis, and debugging (2008)

Dynamic verification methods are the natural choice for formally verifying real world programs when model extraction and maintenance are expensive. Message passing programs written using the MPI library often fall under this category, especially when these programs have to be verified after being ported to new platforms and iteratively optimized. However, implementing dynamic verification tools for MPI requires solving many problems pertaining to the scheduling realities of the MPI runtime. In this paper, we describe the progression of our ideas during the development of our dynamic verification tool for MPI programs, called in-situ partial order (ISP). Each idea developed in this progression relates to our dual goals of ensuring full coverage of all representative interleavings (in the sense of partial order reduction) among MPI processes, and forcing the MPI runtime to affect these interleavings. We briefly examine similar issued faced by other builders of dynamic verification tools. We conclude with observations backing the growing importance of addressing scheduling issues in future dynamic verification tools for various concurrency APIs.
NOYB: privacy in online social networks
Authors: Saikat Guha, Kevin Tang, Paul Francis
Venue: Proceedings of the first workshop on Online social networks (2008)

Increasingly, Internet users trade privacy for service. Facebook, Google, and others mine personal information to target advertising. This paper presents a preliminary and partial answer to the general question "Can users retain their privacy while still benefiting from these web services?". We propose NOYB, a novel approach that provides privacy while preserving some of the functionality provided by online services. We apply our approach to the Facebook online social networking website. Through a proof-of-concept implementation we demonstrate that NOYB is practical and incrementally deployable, requires no changes to or cooperation from an existing online service, and indeed can be non-trivial for the online service to detect.
Fault Nodes in Implication Graph for Equivalence/Dominance Collapsing, and Identifying Untestable and Independent Faults
Authors: Rajamani Sethuram, Michael L. Bushnell, Vishwani D. Agrawal
Venue: Proceedings of the 26th IEEE VLSI Test Symposium (2008)

This paper presents a new fault node for implication graph that represents the Boolean detectability status of afault in the circuit. An implication graph with fault nodes is termed functional fault graph (FFG) because such a graph stores both the functional information and the fault information of the circuit. By computing the transitive closure and graph condensation of the FFG of a circuit, we show that we can collapse faults, and identify untestable faults and independent fault pairs in the circuit. Compared to prior fault independent-based approaches for fault collapsing, our technique gives the best result by reducing the fault-set size by 66%. Additional advantages of our technique compared to previous techniques are: a) It can also identify independent fault pairs in the circuit, and b) It can be extended for other fault models and has a variety of applications. Our experiment with c7552 also found more than 268K independent fault pairs. This work also introduces the first fault-independent polynomial-time approach for identifying untestable transition delay faults.
Environment-Independent Online Real-Time Traffic Identification
Authors: Masaki Tai, Shingo Ata, Ikuo Oka
Venue: Proceedings of the Fourth International Conference on Networking and Services (2008)

In the current Internet, there is a real need for the online real-time traffic identification technique to provide different services for real-time and bulk applications. Previously, it is easy to identify real-time traffic by checking the protocol/port number in IP header, however, it becomes more difficult due to the existence of real-time traffic over TCP connection, P2P and VPN. Previously, we have proposed the online identification method based on flow statistics without checking the protocol/port number to solve these problems. However, this technique performance is unstable due to environment dependency. In this paper, at first, we reanalyze the characteristics of bulk and streaming traffic flows, which shows that the packet arrival interval varies significantly among high-bitrate, low bitrateand bulk flows. Second, we propose a new identification method without using a fixed threshold depending on network environment. Finally, testing shows that its identification accuracy is higher than that of a previous method, which recognizes only two types of flows. It also shows that the improved method is robust against differences in the network environment.
Real world dynamic appearance enhancement with procam feedback
Authors: Toshiyuki Amano, Hirokazu Kato
Venue: Proceedings of the 5th ACM/IEEE International Workshop on Projector camera systems (2008)

In this paper, a dynamic appearance enhancement method for the less saturated object is proposed. The appearance enhancement method proposed in this paper is realized with a projector camera dynamic feed back system. Therefore, the proposed method has an ability of the rapid and continuous appearance enhancement and it is useful for the human visual perception assistance. Also, the system not requires a pre-captured appearance of the target.
Characterizing subgraphs of Hamming graphs
Authors: Sandi Klavžar, Iztok Peterin
Venue: Journal of Graph Theory (2005)

Cartesian products of complete graphs are known as Hamming graphs. Using embeddings into Cartesian products of quotient graphs we characterize subgraphs, induced subgraphs, and isometric subgraphs of Hamming graphs. For instance, a graph G is an induced subgraph of a Hamming graph if and only if there exists a labeling of E(G) fulfilling the following two conditions: (i) edges of a triangle receive the same label; (ii) for any vertices u and v at distance at least two, there exist two labels which both appear on any induced u, &Aring;-path. &copy; 2005 Wiley Periodicals, Inc. J Graph Theory 49: 302312, 2005
Video streaming in mobile ad hoc networks
Authors: Thomas Schierl, Karsten Gänger, Cornelius Hellge, Karsten Grüneberg, Detlev Marpe, Thomas Stockhammer, Thomas Wiegand
Venue: Proceedings of the 2nd international conference on Mobile multimedia communications (2006)

Emerging Mobile Ad-Hoc Networks (MANETs) which do not need access points, but rely on peer-to-peer connections, are becoming suitable platforms for exchanging or sharing real-time video streams due to recent progress in routing algorithms, throughput and transmission bit-rate. In this paper, a multi-source streaming approach is presented to increase the robustness of realtime video transmission in MANETs which are characterized by highly dynamic behavior of the transmission routes and path outage probabilities. Video coding as well as channel coding techniques on application layer are introduced exploiting the multi-source representation of the transferred media. Source coding is based on the Scalable Video Coding (SVC) extension of H.264/MPEG4-AVC. Channel coding is based on a new Un-equal Packet Loss Protection (UPLP) scheme, which is based on Raptor forward error correction codes. Furthermore, an application layer protocol is introduced for supporting peer-to-peer based multi-source streaming in MANETs.
A semantic-expansion approach to personalized knowledge recommendation
Authors: Ting-Peng Liang, Yung-Fang Yang, Deng-Neng Chen, Yi-Cheng Ku
Venue: Decision Support Systems (2008)

The rapid propagation of the Internet and information technologies has changed the nature of many industries. Fast response and personalized recommendations have become natural trends for all businesses. This is particularly important for content-related products and services, such as consulting, news, and knowledge management in an organization. The digital nature of their products allows for more customized delivery over the Internet. To provide personalized services, however, a complete understanding of user profile and accurate recommendation are essential. In this paper, an Internet recommendation system that allows customized content to be suggested based on the user's browsing profile is developed. The method adopts a semantic-expansion approach to build the user profile by analyzing documents previously read by the person. Once the customer profile is constructed, personalized contents can be provided by the system. An empirical study using master theses in the National Central library in Taiwan shows that the semantic-expansion approach outperforms the traditional keyword approach in catching user interests. The proper usage of this technology can increase customer satisfaction.
A note on vertex orders for stability number
Authors: N. V. R. Mahadev, B. A. Reed
Venue: Journal of Graph Theory (1999)

We investigate vertex orders that can be used to obtain maximum stable sets by a simple greedy algorithm in polynomial time in some classes of graphs. We characterize a class of graphs for which the stability number can be obtained by a simple greedy algorithm. This class properly contains previously known classes of graphs for which the stability number can be computed in polynomial time. &copy; 1999 John Wiley & Sons, Inc. J Graph Theory 30: 113&ndash;120, 1999
A lower bound for partial list colorings
Authors: Glenn G. Chappell
Venue: Journal of Graph Theory (1999)

Let G be an n-vertex graph with list-chromatic number &Ccedil;ℓ. Suppose that each vertex of G is assigned a list of t colors. Albertson, Grossman, and Haas [1] conjecture that at least tn-&Ccedil;ℓ vertices can be colored from these lists. We prove a lower bound for the number of colorable vertices. As a corollary, we show that at least ${6}\over{7}$ of the conjectured number can be colored. &copy; 1999 John Wiley Sons, Inc. J Graph Theory 32: 390393, 1999
A randomized maximum-flow algorithm
Authors: J. Cheriyan, T. Hagerup
Venue: Proceedings of the 30th Annual Symposium on Foundations of Computer Science (1989)

The authors present a randomized maximum-flow algorithm, called the PLED (prudent linking excess diminishing) algorithm, whose expected running time is O(nm+n/sup 2/(log n)/sup 3/); this is O(nm) for all except relatively sparse networks. The algorithm is always correct, and in the worst case, which occurs with negligible probability, it take O(nm log n) time. The approach taken is to maintain a parameter Delta , which is a measure of the maximum flow excess of a vertex and of the maximum amount of flow sent by a single operation. Initially, Delta is less than or equal to the maximum edge capacity, and Delta =0 at termination. The execution of the PLED algorithm is partitioned into phases so that Delta stays fixed during each phase and decreases between consecutive phases. In order to achieve a bound on the number of phases that is independent of the maximum edge capacity, the algorithm decreases Delta by as large a factor (>or=2) as possible, rather than by a constant factor. The algorithm uses the dynamic trees data structure.
The complexity of the outer face in arrangements of random segments
Authors: Noga Alon, Dan Halperin, Oren Nechushtan, Micha Sharir
Venue: Proceedings of the twenty-fourth annual symposium on Computational geometry (2008)

We investigate the complexity of the outer face in arrangements of line segments of a fixed length in the plane, drawn uniformly at random within a square. We derive upper bounds on the expected complexity of the outer face, and establish a certain phase transition phenomenon during which the expected complexity of the outer face drops sharply as a function of the total number of segments. In particular we show that up till the phase transition the complexity of the outer face is almost linear in n, and that after the phase transition, the complexity of the outer face is roughly proportional to pn. Our study is motivated by the analysis of a practical point-location algorithm (so-called walk-along-a-line point-location algorithm) and indeed, it explains experimental observations of the behavior of the algorithm on arrangements of random segments.
Naturalistic use of cell phones in driving and context-based user assistance
Authors: Harry Zhang, Christopher Schreiner, Keshu Zhang, Kari Torkkola
Venue: Proceedings of the 9th international conference on Human computer interaction with mobile devices and services (2007)

A field study has been conducted to investigate the naturalistic use of cell phone applications in driving, home, work, and school and during daytime and nighttime. GPS coordinates are used to determine whether cell phone users are driving. The frequency and duration of use of various cell phone applications such as incoming or outgoing voice calls, music player, calendar, SMS, camera, and the Internet are analyzed separately for driving and non-driving. The present results provide fundamental data for adequately assessing the distraction potential of mobile devices and guiding the design of context-based assistance systems.
Cracking Matrix Encryption Row by Row
Authors: Craig Bauer, Katherine Millward
Venue: Cryptologia (2007)

The Hill Cipher, also known as matrix encryption, uses matrices to encipher and decipher text. Various attacks, such as those found by Jack Levine [2, 3, 5], have been published for this system. This article reviews a few previous results and presents a powerful new attack in which the rows of the matrix can be determined independent of one another, greatly reducing the amount of time needed for decipherment.
A sketch of the programmer's coach: making programmers more effective
Authors: David C. Shepherd, Gail C. Murphy
Venue: Proceedings of the 2008 international workshop on Cooperative and human aspects of software engineering (2008)

As programmers work on source code, they ask an array of questions that are difficult to answer manually. To help answer these questions, programmers often employ software tools; often in attempting to use these tools, the programmers encounter many obstacles which frustrate their efforts and lead to less than optimal tool utilization. Possibly worse, programmers often intentionally under utilize available tools as they prefer to answer questions only with tools they have used before. We hypothesize that we can coach programmers towards a more systematic use of appropriate software tools that would enable the programmers to be more productive in the completion of their work. We propose to use activity logs collected automatically to deduce the questions a given programmer asks a frequently and then to coach the programmer automatically on appropriate, possibly unfamiliar, tools to answer those questions more effectively. By using activity logs to inform coaching decisions, our approach is based on an objective cost metric. We envision an environment that enables a programmer to learn how to use appropriate tools systematically.
Novel seamless image mosaicing algorithm for virtual environment
Authors: Dan Liu
Venue: International Journal of Computer Mathematics (2007)

The image mosaic method is an image-based rendering method which is based on the ability to align different views of a scene (overlapped) into a large image and then to blend the image together seamlessly. A smooth image mosaic algorithm for stitching multiple source images together to produce a single output image is proposed. It can effectively eliminate the impact of light and colour difference on the matching of two images, and reduce the possibility of mismatch, without involving intensive computing. It works well for almost all pictures with common characteristics. The algorithm can be easily and efficiently implemented.
Combining computation and data transmission in the systems with switches
Authors: G. G. Stetsyura
Venue: Automation and Remote Control (2008)

New connection structure and computation arrangement are proposed for a multiprocessor system combining computations and data transmission. Fast connection reorganization and computational speedup in such systems are achieved by using non-typically connected switches. Implementation of some typical computational algorithms is considered, computation speed is estimated. It is shown that small modifications in the multiprocessor system arrangement allow to speed up computations with respect to known estimates.
A GENERIC MODEL OF COLLECTIVITIES
Authors: Nigel Gilbert
Venue: Cybernetics and Systems (2007)

A class of social phenomena, exhibiting fluid boundaries and constant change, called 'collectivities,' is modeled using an agent-based simulation, demonstrating how such models can show that a set of plausible microbehaviors can yield the observed macro-phenomenon. Some features of the model are explored and its application to a wide range of social phenomena is described.
Reputation-Based Estimation of Individual Performance in Grids
Authors: Thanasis G. Papaioannou, George D. Stamoulis
Venue: Proceedings of the 2008 Eighth IEEE International Symposium on Cluster Computing and the Grid (2008)

Hidden information is a critical issue for the successful delivery of SLAs in grid systems. It arises when the agents (hardware and software resources) employed to serve a task belong to multiple administrative domains, thus rendering monitoring of remote resource provision absent or unreliable. Therefore, the grid service broker can often observe only the outcome of the collective effort of groups of agents rather than their individual efforts, which makes it hard to identify cases of free-riding or low-performing agents. In this paper, we first identify cases of hidden information in grid systems and explain why they cannot be handled satisfactorily by the existing accounting systems. Second, we develop and evaluate a reputation-based mechanism enabling the grid service broker to deal effectively with hidden information. Our mechanism maintains a reputation metric for each agent; we propose and evaluate several approaches on how to update this metric based only on the observations of collective outcomes.
Spatial-temporal specific neighbourhood rules for cellular automata land-use modelling
Authors: S. Geertman, M. Hagoort, H. Ottens
Venue: International Journal of Geographical Information Science (2007)

This paper explores the necessity of using spatial-temporal specific neighbourhood rules for simulation of urban dynamics at a regional level with the help of a Cellular Automata (CA) land-use model (Environment Explorer). Moreover, it explores a method for formulating these spatial-temporal specific neighbourhood rules. Therein, spatial metrics originating from the field of landscape ecology prove to be very useful, in particular the so-called enrichment factor. Analysis of historical data with the help of these spatial metrics revealed evidence of substantial differences in land-use developments between time periods and regions, for example, differences that should be incorporated in land-use models if applied on a more detailed regional scale. In a case study, micro-scale land-use data incorporated in a CA-model were used to analyse and simulate the urban morphological changes over two time periods in four urban regions in the Netherlands. In this study, regional and time-specific neighbourhood rules performed significantly better than a set of generic neighbourhood rules. In contrast, within current practice, most CA land-use modelling makes use of only one uniform set of neighbourhood rules for performing both large area and regional scale land-use simulations. This study questions this common practice and puts it into perspective. Moreover, it indicates some restrictions in the proposed regionalization of the neighbourhood rules; one which is particularly noteworthy is its time-specific dependency of local developments and circumstances.
R2P: A Peer-to-Peer Transfer System Based on Role and Reputation
Authors: Yingjie Xia, Guanghua Song, Yao Zheng, Mingzhe Zhu
Venue: Proceedings of the First International Workshop on Knowledge Discovery and Data Mining (2008)

This paper introduces R2P, a Peer-to-Peer (P2P) transfer system with role based and reputation based access control policies. With the combination of user authentication, organization authorization and scoring system, we solve the problem of resource piracy, user privacy and network jam, which exist in traditional P2P systems. The R2P system takes advantage of the X509 certificate to implement the role based access control policy. By assembling the artificial scoring and the automatic scoring components, the system evaluates the quantity and quality of the transfer resources, putting forward the reputation based access control policy. Upon the two policies and the adaptive P2P transfer model, the R2P system provides a secure, controllable and efficient resource transfer community.