ppxscal/embedding_network huggingface dataset:
Hierarchical Time-Stamp Protocol: Acquiring Reliable Time-stamp from Local Time Stamping Server
Authors: Xian Pan, J.-L. Zheng
Venue: Proceedings of the 2009 Second International Symposium on Electronic Commerce and Security - Volume 01 (2009)

Time Stamp Protocol (TSP) is a basic security component in e-world, and Time Stamping Server (TSS)as a Trusted Third Party (TTP) generally is implemented on Internet other than in LAN. The acquiring reliability of the existing time-stamp protocols has been mainly focused by researchers in recent years, but the time delay problem produced by frequent time-stamp request has not been paid enough attention to yet. However, simply putting the TSS into LAN may deteriorate its reliability.To solve this problem, a novel Hierarchical Time-Stamp Protocol (HTSP) is proposed in this paper which enables making reliable time stamp in LAN. The hierarchy model in HTSP contains two TSS: Internet TSS and local TSS.Therefore, the advantage of a quick time stamp response of the local TSS is used, whereas the disadvantage of a possible time stamp fake in the local TSS could be overcome by periodically acquiring time stamp from the Internet TSS. The security analysis shows that reliability of time stamp in the HTSP is still remaining unchanged in comparison with the current TSP.
Space-time tradeoffs for approximate nearest neighbor searching
Authors: Sunil Arya, Theocharis Malamatos, David M. Mount
Venue: Journal of the ACM (JACM) (2009)

Nearest neighbor searching is the problem of preprocessing a set of n point points in d-dimensional space so that, given any query point q, it is possible to report the closest point to q rapidly. In approximate nearest neighbor searching, a parameter &epsiv; > 0 is given, and a multiplicative error of (1 + &epsiv;) is allowed. We assume that the dimension d is a constant and treat n and &epsiv; as asymptotic quantities. Numerous solutions have been proposed, ranging from low-space solutions having space O(n) and query time O(log n + 1/&epsiv;d&minus;1) to high-space solutions having space roughly O((n log n)/&epsiv;d) and query time O(log (n/&epsiv;)). We show that there is a single approach to this fundamental problem, which both improves upon existing results and spans the spectrum of space-time tradeoffs. Given a tradeoff parameter &gamma;, where 2 &le; &gamma; &le; 1/&epsiv;, we show that there exists a data structure of space O(n&gamma;d&minus;1 log(1/&epsiv;)) that can answer queries in time O(log(n&gamma;) + 1/(&epsiv;&gamma;)(d&minus;1)/2. When &gamma; &equals; 2, this yields a data structure of space O(n log (1/&epsiv;)) that can answer queries in time O(log n + 1/&epsiv;(d&minus;1)/2). When &gamma; &equals; 1/&epsiv;, it provides a data structure of space O((n/&epsiv;d&minus;1)log(1/&epsiv;)) that can answer queries in time O(log(n/&epsiv;)). Our results are based on a data structure called a (t,&epsiv;)-AVD, which is a hierarchical quadtree-based subdivision of space into cells. Each cell stores up to t representative points of the set, such that for any query point q in the cell at least one of these points is an approximate nearest neighbor of q. We provide new algorithms for constructing AVDs and tools for analyzing their total space requirements. We also establish lower bounds on the space complexity of AVDs, and show that, up to a factor of O(log (1/&epsiv;)), our space bounds are asymptotically tight in the two extremes, &gamma; &equals; 2 and &gamma; &equals; 1/&epsiv;.
The Effects of Type of Interactivity in Experiential Game-Based Learning
Authors: Ming-Puu Chen, Li-Chun Wang
Venue: Proceedings of the 4th International Conference on E-Learning and Games: Learning by Playing. Game-based Education System Design and Development (2009)

The purpose of this study was to examine the effects of type of interactivity, prior knowledge and gender on learners' performance in learning computer programming skills through an experiential game-based learning activity. One hundred and forty six junior high school students participated in the experimental activity. Participants' levels of prior-knowledge (high vs. low) were identified according to previous computer course performance. The interactions of type-of-interactivity-prior-knowledge and type-of-interactivity-gender were significant on participants' performance. The analysis revealed that (a) for the gender effect, the male group outperformed the female group while receiving the challenge-interactivity game-play activity, but while receiving the mixed-interactivity game-play activity, the male group and the female group performed equally; (b) similarly, for the prior-knowledge effect, the high prior-knowledge group outperformed the low prior-knowledge group while receiving the challenge-interactivity game-play activity, but while receiving the mixed-interactivity game-play activity, the high prior-knowledge group and the low prior-knowledge group performed equally. The mixed-interactivity game-play was found to compensate for females' gender disadvantage and insufficient prior-knowledge.
Regularisation of 3D Signed Distance Fields
Authors: Rasmus R. Paulsen, Jakob Andreas Bærentzen, Rasmus Larsen
Venue: Proceedings of the 16th Scandinavian Conference on Image Analysis (2009)

Signed 3D distance fields are used a in a variety of domains. From shape modelling to surface registration. They are typically computed based on sampled point sets. If the input point set contains holes, the behaviour of the zero-level surface of the distance field is not well defined. In this paper, a novel regularisation approach is described. It is based on an energy formulation, where both local smoothness and data fidelity are included. The minimisation of the global energy is shown to be the solution of a large set of linear equations. The solution to the linear system is found by sparse Cholesky factorisation. It is demonstrated that the zero-level surface will act as a membrane after the proposed regularisation. This effectively closes holes in a predictable way. Finally, the performance of the method is tested with a set of synthetic point clouds of increasing complexity.
VRV-CAN Network Simulation System Design Based on CANoe
Authors: Zhang Junxing, Shi Lixin, Wang Dusheng
Venue: Proceedings of the 2009 International Forum on Information Technology and Applications - Volume 01 (2009)

The CANoe is adopted to finish the VRV-CAN network simulation system design so as to solve the problem of too many communication nodes, complex communication content within the system. The simulation procedure and means in CANoe are described with emphasis on the discussion of network architecture, communication protocol and network load ratio. The simulation results are presented. Through the system simulation, the communication protocol and design scheme are verified and the development speed is increasingly improved.
A Trinocular Stereo System for Detection of Thin Horizontal Structures
Authors: Klas Hedenberg, Björn Astrand
Venue: Proceedings of the Advances in Electrical and Electronics Engineering - IAENG Special Edition of the World Congress on Engineering and Computer Science 2008 (2008)

Many vision-based approaches for obstacle detection often state that vertical thin structure is of importance, e.g. poles and trees. However, there are also problem in detecting thin horizontal structures. In an industrial case there are horizontal objects, e.g. cables and fork lifts, and slanting objects, e.g. ladders, that also has to be detected. This paper focuses on the problem to detect thin horizontal structures. We introduce a test apparatus for testing thin objects as a complement for the test pieces for human safety described in the European standard EN 1525 Safety of industrial trucks – Driverless trucks and their systems. The system uses three cameras, situated as a horizontal pair and a vertical pair, which makes it possible to also detect thin horizontal structures. A sparse disparity map based on edges and a dense disparity map is used to identify problems with a trinocular system. Both methods use the Sum of Absolute Difference to compute the disparity maps. Tests show that the proposed trinocular system detects all objects at the test apparatus. If a sparse or dense method is used is not critical. Further work will implement the algorithm in real time and verify it on a final system in many types of scenery.
Learning grasping affordances from local visual descriptors
Authors: Luis Montesano, Manuel Lopes
Venue: Proceedings of the 2009 IEEE 8th International Conference on Development and Learning (2009)

In this paper we study the learning of affordances through self-experimentation. We study the learning of local visual descriptors that anticipate the success of a given action executed upon an object. Consider, for instance, the case of grasping. Although graspable is a property of the whole object, the grasp action will only succeed if applied in the right part of the object. We propose an algorithm to learn local visual descriptors of good grasping points based on a set of trials performed by the robot. The method estimates the probability of a successful action (grasp) based on simple local features. Experimental results on a humanoid robot illustrate how our method is able to learn descriptors of good grasping points and to generalize to novel objects based on prior experience.
Semantic analysis of program initialisation in genetic programming
Authors: Lawrence Beadle, Colin G. Johnson
Venue: Genetic Programming and Evolvable Machines (2009)

Population initialisation in genetic programming is both easy, because random combinations of syntax can be generated straightforwardly, and hard, because these random combinations of syntax do not always produce random and diverse program behaviours. In this paper we perform analyses of behavioural diversity, the size and shape of starting populations, the effects of purely semantic program initialisation and the importance of tree shape in the context of program initialisation. To achieve this, we create four different algorithms, in addition to using the traditional ramped half and half technique, applied to seven genetic programming problems. We present results to show that varying the choice and design of program initialisation can dramatically influence the performance of genetic programming. In particular, program behaviour and evolvable tree shape can have dramatic effects on the performance of genetic programming. The four algorithms we present have different rates of success on different problems.
Positive solutions of periodic boundary value problems for impulsive differential equations
Authors: Weibing Wang, Xiangling Fu, Xuxin Yang
Venue: Computers Mathematics with Applications (2009)

In this paper, we discuss the existence of positive solutions of periodic boundary value problems for second-order impulsive equations. The existence and multiplicity of positive solutions are established and the proof is based upon fixed point theorems in cone.
2D Geometric Constraint Solving: An Overview
Authors: Samy Ait-Aoudia, Mehdi Bahriz, Lyes Salhi
Venue: Proceedings of the 2009 Second International Conference in Visualisation (2009)

Geometric constraint solving has applications in many different fields, such as Computer-Aided Design, molecular modelling, tolerance analysis, and geometric theorem proving. Geometric modelling by constraints enables users to describe shapes by relationships called constraints between geometric elements. The aim is to derive automatically these geometric elements and provide thus effort and time saving. Moreover, users can easily modify existing designs. Many resolution methods have been proposed for solving systems of geometric constraints. We classify these methods in three broad categories: algebraic, rule-oriented and graph-constructive solvers.
Distributed complex event processing with query rewriting
Authors: Nicholas Poul Schultz-Møller, Matteo Migliavacca, Peter Pietzuch
Venue: Proceedings of the Third ACM International Conference on Distributed Event-Based Systems (2009)

The nature of data in enterprises and on the Internet is changing. Data used to be stored in a database first and queried later. Today timely processing of new data, represented as events, is increasingly valuable. In many domains, complex event processing (CEP) systems detect patterns of events for decision making. Examples include processing of environmental sensor data, trades in financial markets and RSS web feeds. Unlike conventional database systems, most current CEP systems pay little attention to query optimisation. They do not rewrite queries to more efficient representations or make decisions about operator distribution, limiting their overall scalability. This paper describes the NEXT CEP system that was especially designed for query rewriting and distribution. Event patterns are specified in a high-level query language and, before being translated into event automata, are rewritten in a more efficient form. Automata are then distributed across a cluster of machines for detection scalability. We present algorithms for query rewriting and distributed placement. Our experiments on the Emulab test-bed show a significant improvement in system scalability due to rewriting and distribution.
Energy Efficient Sensor Network with Service Discovery for Smart Home Environments
Authors: Harri Pensas, Henrik Raula, Jukka Vanhala
Venue: Proceedings of the 2009 Third International Conference on Sensor Technologies and Applications (2009)

A communications network for sensors and actuators is an important part in the realization of any smart home or intelligent environment. This paper presents a new protocol specialized for smart home environments emphasizing energy efficiency and service discovery functionality. Energy efficiency has been attained by using device specific low power listening schemes together with minimal number of message transactions. This protocol was compared to other academic and industry protocols and found promising for use in smart home environments. Prototype implementation of the new protocol has been implemented using TinyOS, a wireless sensor network enabled operating system.
Order matters: transmission reordering in wireless networks
Authors: Justin Manweiler, Naveen Santhapuri, Souvik Sen, Romit Roy Choudhury, Srihari Nelakuditi, Kamesh Munagala
Venue: Proceedings of the 15th annual international conference on Mobile computing and networking (2009)

Modern wireless interfaces support a physical layer capability called Message in Message (MIM). Briefly, MIM allows a receiver to disengage from an ongoing reception, and engage onto a stronger incoming signal. Links that otherwise conflict with each other, can be made concurrent with MIM. However, the concurrency is not immediate, and can be achieved only if conflicting links begin transmission in a specific order. The importance of link order is new in wireless research, motivating MIM-aware revisions to link scheduling protocols. This paper identifies the opportunity in MIM-aware reordering, characterizes the optimal improvement in throughput, and designs a link layer protocol to achieve it. Testbed results confirm the performance gains of the proposed system.
Exploring interactional moves in a CSCL environment for Chinese language learning
Authors: Chee-Kit Looi, Wenli Chen, Yun Wen
Venue: Proceedings of the 9th international conference on Computer supported collaborative learning - Volume 1 (2009)

This work analyzes the interactions of small groups of students doing collaborative learning activities in the primary classroom for learning Chinese as a second language. We take the perspective of identifying the characteristics of interactional moves as students interact and negotiate meaning in the computer-mediated collaborative learning (CSCL) environment called GroupScribbles (GS). Much work in group cognition and in interactional analysis of small groups looks at problem-solving in subjects like mathematics and science. In language learning, the task posed for collaborative activities does not focus on problem-solving, but it may be targeted towards enriching students' vocabulary and proficiency in language expression, developing their thoughts and writing through cogitating with new words, vocabulary and sentence construction. We hope the work can illuminate how students can co-construct knowledge mediated by GS representations for Chinese language learning. In the paper, we look at collaborative situations in which the group members are not seated together in the classroom, and so they have to collaborate through the GS medium.
A comparison of single- and multi-hop beaconing in VANETs
Authors: Jens Mittag, Florian Thomas, Jérôme Härri, Hannes Hartenstein
Venue: Proceedings of the sixth ACM international workshop on VehiculAr InterNETworking (2009)

Optimizing vehicular communication strategies is important for an efficient usage of the available wireless bandwidth and also critical for the success of VANETs. In this paper we address the fundamental and practical question whether the load on the wireless channel can be reduced if periodic beacon messages are transmitted over multiple hops with reduced transmit power instead of being transmitted over one hop with high transmit power. In particular, we look at the possible bandwidth savings that can be achieved by piggybacking forwarded messages into the own next beacon transmission. For that matter, we first propose an analytical model to compute a lower bound for the resulting channel load when single- or multi-hop dissemination of beacons is performed. In this model we assume optimal channel conditions and perfect relaying and piggybacking decisions to show that a reduction of the load by multi-hop is possible and closely related to piggybacking. Further, we show that the possible savings depend on the ratio between the size of the header and the payload of a beacon and that a reduction of the load is theoretically possible if the header is larger than the payload - what would be the case in VANETs if security overheads are considered part of the header. We then perform a simulative comparison of single- and multi-hop beaconing to evaluate the impact of effects such as packet collisions and channel fading. We show that the possible savings of multi-hop beaconing are difficult to exploit under non-perfect channel conditions and suboptimal relaying decisions.
The importance of privacy revisited
Authors: Norman Mooradian
Venue: Ethics and Information Technology (2009)

James Rachels' seminal paper "Why Privacy Is Important" (1975) remains one of the most influential statements on the topic. It offers a general theory that explains why privacy is important in relation to mundane personal information and situations. According to the theory, privacy is important because it allows us to selectively disclose personal information and to engage in behaviors appropriate to and necessary for creating and maintaining diverse personal relationships. Without this control, it is implied, the diversity of relationships would diminish; relationships would "flatten out", we might say. The aspect of the paper that addresses information flows (what I refer to as his information privacy theory) has been of particular interest to computer information privacy theorists. Despite its continued importance to computer privacy theorists, however, the information privacy theory appears to be contradicted by recent developments in computing. In particular, since the publication of Rachels' paper we have seen an extensive amount of personal information collected. Further, recent developments in computing falling under the heading of social computing have brought about a new wave of personal information creation and collection. This paper will reassess and resituate Rachels' information privacy theory in light of these developments. I will argue that the increasing collection of personal data will not flatten relationships as the information privacy theory predicts because such data lack contextual factors important to Rachels' general theory. The paper will conclude by pointing to some areas where Rachels' general theory and where his information privacy theory will continue to be relevant.
A Segment and Fusion-Based Stereo Approach
Authors: Frank Pagel
Venue: Proceedings of the 2009 Canadian Conference on Computer and Robot Vision (2009)

Most algorithms in stereo vision work on rectified images and therefore find the point correspondences row by row. So especially for standard block-matching algorithms periodic patterns are a problem in determining corresponding features reliably.This contribution describes a segment-based approach that allows the detection and removal of single outliers in an arbitrary dense disparity map and so improves the data quality. The first step is a matching of vertical edge segments in the images in a coarse to fine strategy.Then the segment information is taken into account. Even more, when using segments there is only need to calculate feature correspondences for a fraction of the image rows, which considerably reduces computation time. By fusing this information with the disparity map of the standard block matching algorithm a significant improvement of the resulting disparity map in the presence of periodic patterns can be reached.
Combining Ehrenfeucht-Fraïssé Games
Authors: Benjamin Rossman
Venue: Proceedings of the 2009 24th Annual IEEE Symposium on Logic In Computer Science (2009)

Ehrenfeucht-Fraisse games are a useful technique for proving inexpressibility results in first-order logic. Strategies for a few basic games (on long paths, set-powerset structures and random graphs, to name a few) can be used as a building blocks for strategies in more complicated games. In this talk, I will discuss a few general methods for combining strategies. Applications include results on the expressive power of successor-invariant logic and k-variable logic. 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 "person" in the interface: effects on user perceptions of multibiometrics
Authors: Álvaro Hernández, Beatriz López, David Díaz, Rubén Fernández, Luis Hernández, Javier Caminero
Venue: Proceedings of the Workshop on Embodied Language Processing (2007)

In this paper we explore the possibilities that conversational agent technology offers for the improvement of the quality of human-machine interaction in a concrete area of application: the multimodal biometric authentication system. Our approach looks at the user perception effects related to the system interface rather than to the performance of the biometric technology itself. For this purpose we have created a multibiometric user test environment with two different interfaces or interaction metaphors: one with an embodied conversational agent and the other with on-screen text messages only. We present the results of an exploratory experiment that reveals interesting effects, related to the presence of a conversational agent, on the user's perception of parameters such as privacy, ease of use, invasiveness or system security.
Research Summary
Authors: Frank Raiser
Venue: Proceedings of the 25th International Conference on Logic Programming (2009)

Constraint Handling Rules (CHR) [1] has become a general-purpose rule-based programming language throughout the last decade. The relations to many other formalisms have been investigated [2] and often results could be transferred from CHR to other formalisms, or vice versa. 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