ppxscal/embedding_network huggingface dataset:
A Fully Distributed Spatial Index for Wireless Data Broadcast
Authors: Wang-Chien Lee, Baihua Zheng
Venue: Proceedings of the 21st International Conference on Data Engineering (2005)

To support location-based services in wireless data broadcast systems, a distributed spatial index (called DSI) is proposed in this paper. DSI is highly efficient because it has a linear yet fully distributed structure that naturally facilitates multiple replications of the index by sharing links in different search trees. Search algorithms for point queries, window queries, and kNN queries, based on DSI are presented. Empirical evaluation of DSI are conducted. Result shows that DSI significantly out-performs R-tree and Hilbert Curve Index, two state-of-the-art spatial indexing techniques for wireless data broadcast.
Slot allocation strategies for delay sensitive traffic support in asynchronous ad hoc wireless networks: Research Articles
Authors: B. S. Manoj, V. Vidhyashankar, C. Siva Ram Murthy
Venue: Wireless Communications Mobile Computing (2005)

Supporting real-time traffic in ad hoc wireless networks is considered as a challenging problem. Existing bandwidth reservation mechanisms assume a TDMA environment where achieving time synchronisation is expensive in terms of resources. Heuristics that exist for slot allocation schemes assume a CDMA over TDMA model in order to alleviate the presence of hidden terminals. Slot allocation strategies in the presence of hidden terminals assume significance in a single channel system for supporting delay sensitive traffic. In this paper, we propose three heuristics for the slot allocation process in asynchronou single channel multihop wireless networks in the presence of hidden terminals. The heuristics we propose are the early fit reservation (EFR), minimum bandwidth-based reservation (MBR) and position-based hybrid reservation (PHR). The EFR heuristic assigns bandwidth link-by-link in the forward path. The MBR heuristic allocates bandwidth to the links in the increasing order of free conn-slots. The PHR heuristic assigns bandwidth for every link proportional to its position in the path. Simulation studies show that EFR performs better in terms of delay characteristics. MBR provides better call blocking performance at the cost of high end-to-end delay. PHR provides a better delay performance compared to MBR and better call blocking performance comparedto EFR. Copyright &copy; 2004 John Wiley & Sons, Ltd.
Sharing the big apple: a survey study of people, place and locatability
Authors: Sukeshini A. Grandhi, Quentin Jones, Samer Karam
Venue: CHI '05 extended abstracts on Human factors in computing systems (2005)

With the advancement in technologies to locate individuals, there has been an emergence of information systems that link People-to-People-to-Geographical-Places, labeled P3-Systems. While various P3-System services have been proposed and deployed, there is limited knowledge on people's desires and attitudes towards such services. We used the P3-Systems framework to guide a survey study of the impact of 'place' on people's social information needs and willingness to share personal location data. At fourteen different place types (Restaurant, Post Office, Etc.) in Manhattan, New York, we surveyed 509 individuals over 3 weeks. The vast majority of respondents expressed a desire for and willing to share their personal location data. E.g., 77% of respondents were willing to reveal their current location to others (17% with complete strangers).
Full analysis of the triple integrator problem
Authors: A. I. Kozlov, D. Yu. Muromtsev
Venue: Automation and Remote Control (2005)

Consideration was given to the full analysis of the problem of optimal control using the method of synthesizing variables. The problem of control was formulated as that with fixed ends of the trajectory of the phase coordinate vector, fixed time interval, and bounded control. The plant dynamics was described by the model of the triple integrator, the functional being the power consumption. The results obtained can be used in the real-time design of power-saving control actions in the control systems of plants whose dynamics obeys differential equations of the third order.
Cryptanalysis of Xia-You group signature scheme
Authors: Zuhua Shao
Venue: Journal of Systems and Software (2005)

Group signature is a variant of digital signatures, which allows members of a group to sign messages anonymously on behalf of he group. The application of group signatures includes e-voting, e-bidding and e-cash. Recently, Xia and You proposed an identity-based group signature scheme with Strong separability. In this paper, however, we find that there are several problems in the Xia-You group signature scheme. This scheme is vulnerable to forgery attacks. Any adversary could easily forge a valid group signature for any message without the knowledge of the secret values of the legal members of the group. Furthermore, the Xia-You group signature scheme does not satisfy nearly all other security requirements of group signatures. The signatures are too long to be computed, stored and transmitted.
s-power series: an alternative to Poisson expansions for representing analytic functions
Authors: J. Sánchez-Reyes, J. M. Chacón
Venue: Computer Aided Geometric Design (2005)

Morin and Goldman [Computer Aided Geometric Design 17 (2000) 813] have recently presented a remarkable new framework, based on employing Poisson series, for describing analytic functions in CAD. We compare this Poisson formulation with s-power series, modified Newton series that can be regarded as the two-point analogue of Taylor expansions. Such s-power series yield, over finite intervals, better approximations for CAD purposes, as they are polynomial and hence expressible in the Bernstein-Bézier standard, can be pieced together in a smooth Hermitian spline and, in general, display better convergence.
Cost-Driven General Join View Maintenance over Distributed Data Sources
Authors: Bin Liu, Elke A. Rundensteiner
Venue: Proceedings of the 21st International Conference on Data Engineering (2005)

Maintainingmaterialized views that have join conditions between arbitrary pairs of data sources possibly with cycles is critical for many applications. In this work, we model view maintenance as the process of answering a set of inter-related distributed multi-join queries. We illustrate two strategies for maintaining as well as optimizing such general join views. We propose a cost-driven view maintenance framework which generates optimized maintenance plans tuned to a given environmental settings. This framework can significantly improve view maintenance performance especially in a distributed environment.
Geometry-driven physical interaction between avatars and virtual environments: Research Articles
Authors: Harald Schmidl, Ming C. Lin
Venue: Computer Animation and Virtual Worlds (2004)

We present an interactive technique on virtual contact handling for avatars in virtual environments using geometry-driven physics. If a contact has occurred between an articulated avatar and a virtual environment, the global penetration depth and contact points are estimated based on a fast local penetration depth computation for decomposed convex pieces. The penetration depth and contact information are then used to resolve overlap between the avatar and the virtual environment. If applicable, joint angles for an articulated body are computed using an inverse kinematics approach based on cyclic coordinate descent. Resulting dynamic response with friction is modeled with impulse-based dynamics under the Coulomb friction law. We demonstrate the algorithm on a modestly complex virtual environment. The resulting system is able to maintain an interactive frame rate of 30&ndash;60&thinsp;Hz. Copyright &copy; 2004 John Wiley & Sons, Ltd.
Guest Editors' Introduction: Approaches to Recovery-Oriented Computing
Authors: Armando Fox, David Patterson
Venue: IEEE Internet Computing (2005)

Given that hardware fails, software has bugs, and human operators make mistakes, researchers must increasingly consider recovery-oriented approaches to dependability. The articles in this issue's theme section describe how a range of techniques based on these perspectives canaugment and complement other efforts to improve dependability.
An Analysis of Database-Driven Mail Servers
Authors: Nick Elprin, Bryan Parno
Venue: Proceedings of the 17th USENIX conference on System administration (2003)

This paper compares the performance of three different IMAP servers, each of which uses a different storage mechanism: Cyrus uses a database built on BerkeleyDB, Courier-IMAP uses maildirs, and UW-IMAP uses mbox files. We also use a mySQL database to simulate a relational-database-driven IMAP server. We find that Cyrus and mySQL outperform UW and Courier in most tests, often dramatically beating Courier. Cyrus is particularly efficient at scan operations such as retrieving headers, and it also does particularly well on searches on header fields. UW and Cyrus perform similarly on full-text searches, although Cyrus seems to scale slightly better as the size of the mailbox grows. mySQL excels at full-text searches and header retrieval, but it performs poorly when deleting messages. In general, we believe that a database system offers better email storage facilities than traditional file systems.
Image Denoising Using Wavelet and Support Vector Regression
Authors: Hui Cheng, Qiuze Yu, Jinwen Tian, Jian Liu
Venue: Proceedings of the Third International Conference on Image and Graphics (2004)

Wavelet image denoising has been well acknowledged as an important method of denoising in image processing. This paper describers a new method for the suppression of noise in image by fusing the wavelet denoising technique with support vector regression (SVR). Based on the least squares support vector machine (LS-SVM), a new denoising operators used in the wavelet domain are obtained. Simulated noise images are used to evaluate the denoising performance of proposed algorithm along with another wavelet-based denoising algorithm. Experimental results show that the proposed denoising method outperforms standard wavelet denoising techniques in terms of the signal-to-noise ratio and the prevented edge information in most cases. It also achieves better performance than the median filter.
Trust-based secure information sharing between federal government agencies: Research Articles
Authors: Peng Liu, Amit Chetal
Venue: Journal of the American Society for Information Science and Technology (2005)

The September 11 attack and the following investigations show that there is a serious information sharing problem among the relevant federal government agencies, and the problem can cause substantial deficiencies in terrorism attack detection. In this paper we provide a systematic analysis of the causes of this problem; and conclude that existing secure information sharing technologies and protocols cannot provide enough incentives for government agencies to share information with each other without worrying that their own interests can be jeopardized. Although trust-based information access is well studied in the literature, the existing trust models, which are based on certified attributes, cannot support effective information sharing among government agencies, which requires an interest-based trust model. To solve this information sharing problem, we propose an innovative interest-based trust model and a novel information sharing protocol, where a family of information sharing policies are integrated, and information exchange and trust negotiation are interleaved with and interdependent upon each other. In addition, an implementation of this protocol is presented using the emerging technology of XML Web Services. The implementation is totally compatible with the Federal Enterprise Architecture reference models and can be directly integrated into existing E-Government systems.
Contextor: capture and dynamic distribution of contextual information
Authors: Gaëtan Rey, Joëlle Coutaz
Venue: Proceedings of the 1st French-speaking conference on Mobility and ubiquity computing (2004)

Without the support of adequate software infrastructures, the implementation of context sensitive interactive systems is hard to achieve in a sound way. In this article, we propose the notion of contextor, a software abstraction that supports the operational deployment of interaction contexts. We show how contextors are organized into levels of abstraction, and how these levels fit within the Arch architecture reference model for interactive systems. Based on the P2P paradigm, the contextor infrastructure is intended to support both mobility and ubiquity. Similar in spirit to the Context Toolkit, we make the differences explicit.
Vibrotactile Pattern Recognition on the Arm and Torso
Authors: Erin Piateski, Lynette Jones
Venue: Proceedings of the First Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (2005)

A tactile display for use in navigation has been designed and evaluated. In these experiments, the ability of subjects to identify patterns of vibrotactile stimulation was tested using tactile displays mounted on the arm and torso. The performance of two types of motors (pancake and cylindrical) was also compared at both sites. The results indicated that identification of the vibrotactile patterns was superior on the torso as compared to the forearm, with subjects achieving 99-100% accuracy with seven of the eight patterns presented.
Automatic generation of high coverage usability tests
Authors: Renée C. Bryce
Venue: CHI '05 extended abstracts on Human factors in computing systems (2005)

Software systems are often complex in the number of features that are available through the user interface and consequently, the number of interactions that can occur. Such systems are prone to errors when interactions do not work as anticipated. This research introduces a combinatorial method for setting up task-based usability tests. The method bridges contributions from mathematics, design of experiments, software test, and algorithms for application to usability testing.
Fractional step methods for index-1 differential-algebraic equations
Authors: Prashanth K. Vijalapura, John Strain, Sanjay Govindjee
Venue: Journal of Computational Physics (2005)

In the numerical solution of ordinary differential systems, the method of fractional steps (also known as operator splitting) yields high-order accurate schemes based on separate, computationally convenient treatments of distinct physical effects. Such schemes are equally desirable but much less accurate for semi-explicit index-1 differential-algebraic equations (DAEs). In the first half of this note, it is shown that nai@?ve application to DAEs of standard splitting schemes suffers from order reduction: both first and second-order schemes are only first-order accurate for DAEs. In the second half of this note, a new family of higher-order splitting schemes for semi-explicit index-1 DAEs is developed. The new schemes are based on a deferred correction paradigm in which an error equation is solved numerically, and therefore inherit a simple computationally convenient structure. Higher-order convergence of the new schemes is proved, and numerical results confirm the expected order of accuracy in addition to establishing efficiency.
Tunneling IPv6 through NAT with Teredo Mechanism
Authors: Shiang-Ming Huang, Quincy Wu, Yi-Bing Lin
Venue: Proceedings of the 19th International Conference on Advanced Information Networking and Applications - Volume 2 (2005)

Teredo is a service that enables hosts located behind one or more IPv4 NATs to obtain IPv6 connectivity by tunneling packets over IPv4 UDP. Under the national IPv6 deployment project in Taiwan, we developed the first Linux-based Teredo service in 2003. In this paper, we explain how IPv6 candidates located behind NATs can enlist the help of "Teredo servers" and "Teredo relays" to learn their "global addresses" and to obtain connectivity, and how clients, servers and relays can be organized in Teredo networks. We also describe in details our strategies for implementing Teredo server and Teredo relay under Linux, and show the performance of different Teredo implementations in public domain.
Dense Photometric Stereo Using a Mirror Sphere and Graph Cut
Authors: Tai-Pang Wu, Chi-Keung Tang
Venue: Proceedings of the 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'05) - Volume 1 - Volume 01 (2005)

We present a surprisingly simple system that performs robust normal reconstruction by dense photometric stereo, in the presence of large shadows, highlight, transparencies, complex geometry, variable attenuation in light intensity and inaccurate light directions. Our system consists of a mirror sphere, a spotlight and a DV camera only. Using this, we infer a dense set of unbiased but noisy photometric data uniformly distributed on the light direction sphere. We use this dense set to derive a very robust matching cost for our MRF photometric stereo model, where the Maximum A Posteriori (MAP) solution is estimated. To aggregate support for candidate normals in the normal refinement process, we introduce a compatibility function that is translated into a discontinuity-preserving metric, thus speeding up the MAP estimation by energy minimization using graph cut. No reference object of similar material is used. We perform detailed comparison on our approach with conventional convex minimization. We show very good normals estimated from very noisy data on a wide range of difficult objects to show the robustness and usefulness of our method.
A General Cooperative Intrusion Detection Architecture for MANETs
Authors: D. Sterne, P. Balasubramanyam, D. Carman, B. Wilson, R. Talpade, C. Ko, R. Balupari, C-Y. Tseng, T. Bowen, K. Levitt, J. Rowe
Venue: Proceedings of the Third IEEE International Workshop on Information Assurance (2005)

Intrusion detection in MANETs is challenging because these networks change their topologies dynamically; lack concentration points where aggregated traffic can be analyzed; utilize infrastructure protocols that are susceptible to manipulation; and rely on noisy, intermittent wireless communications. We present a cooperative, distributed intrusion detection architecture that addresses these challenges while facilitating accurate detection of MANET-specific and conventional attacks. The architecture is organized as a dynamic hierarchy in which detection data is acquired at the leaves and is incrementally aggregated, reduced, and analyzed as it flows upward toward the root. Security management directives flow downward from nodes at the top. To maintain communications efficiency, the hierarchy is automatically reconfigured as needed using clustering techniques in which clusterheads are selected based on topology and other criteria. The utility of the architecture is illustrated via multiple attack scenarios.
The 3-D Karnaugh map
Authors: Michael J. Reale
Venue: Journal of Computing Sciences in Colleges (2005)

As a graphical aid in reducing Boolean canonical expressions, K-maps are very useful. However, a two-dimensional Karnaugh map can fit at most 4 variables. This project explores an implementation of a 3D Karnaugh map. Programmed entirely in JAVA, it utilizes an advanced GUI that allows the user to input binary information (either directly or by opening an appropriate file), to convert it to DNF (SOP) or CNF (POS), and to construct an appropriate 3D Karnaugh map for it. The implementation involved development of a simple 3D graphics engine that can display multi-colored "bricks" with some shading. These cubes represent the data values using color codes. We automatically reduce the map and display the reduction. Other GUI enhancements allow the user to select bricks, make bricks "disappear" and "reappear" (to facilitate selection of obscured bricks), and rotate the display, as well as toggle bricks "on" and "off" in modification mode. The user also has the option to manually reduce the K-map in reduction mode.
Using intimacy, chronology and zooming to visualize rhythms in email experience
Authors: Mirko Mandic, Andruid Kerne
Venue: CHI '05 extended abstracts on Human factors in computing systems (2005)

Experiences of intimacy and connectedness through social networks are vital to human sense of well-being. We live in an electronic habitat. Electronic mail functions as a medium of interpersonal exchange. As it accumulates, email data becomes more than a collection of reminders. It is a diary we didn't know we were keeping, and a potential source of valuable insight into the structure and dynamics of one's social network. Current interfaces do little to help users see patterns of social interaction within email data.We introduce a multiscale email interface that utilizes computed intimacy measures and chronology as parameters for information visualization. Rhythms of intimacy in email experience are made visible as patterns of color and shapes in a zoomable chronological grid. Qualitative user experience data indicates that such an email visualization can provide striking insights into the experience of social connectedness over time. These insights potentially enable users to better manage how they invest time and energy into personal and work relationships, and thus to improve overall sense of well-being.
On the statistical properties of least-square estimators of layered neural networks
Authors: Masashi Kitahara, Taichi Hayasaka, Naohiro Toda, Shiro Usui
Venue: Systems and Computers in Japan (2004)

There are still some statistical properties which have not been clarified in the regression model based on the three-layered neural network. This paper presents an analysis of these problems, in terms of the probability distribution of the parameter estimators. It is first shown numerically that the least-square estimator for the condition in which the probability distribution for the parameter estimator has not been clearly described follows a distribution which is different from the probability distribution derived in the past for various conditions. Based on the result, a theoretical analysis is presented for the simplified regression model, and it is shown that the least-square parameter estimator follows the double-exponential distribution. &copy; 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(12): 1&ndash;9, 2004; Published online in Wiley InterScience (). DOI 10.1002&sol;scj.10580
A Gradient-based Continuous Method for Large-scale Optimization Problems
Authors: Li-Zhi Liao, Liqun Qi, Hon Wah Tam
Venue: Journal of Global Optimization (2005)

In this paper, we study a gradient-based continuous method for large-scale optimization problems. By converting the optimization problem into an ODE, we are able to show that the solution trajectory of this ODE tends to the set of stationary points of the original optimization problem. We test our continuous method on large-scale problems available in the literature. The simulation results are very attractive.
Implementation of international accounting standard 39
Authors: Sevdalina Draganova, Svetlozar Stefanov
Venue: Proceedings of the 5th international conference on Computer systems and technologies (2004)

The paper describes an implementation of a module for calculating fair values and balance values of financial instruments, according to International Accounting Standard 39. Position balance values are estimated by Amortization Cost Method (method of effectiveness rate of interest). This module is part of Portfolio Management System (PMS) of Much-Net AG. The module is developed in Microsoft Visual C++. The application is a Windows PC based system that operates on many database/data sources.