ppxscal/embedding_network huggingface dataset:
Applying Petri Nets to Model SCORM Learning Sequence Specification in Collaborative Learning
Authors: H. W. Lin, Wen-Chih Chang, George Yee, Timothy K. Shih, Chun-Chia Wang, Hsuan-Che Yang
Venue: Proceedings of the 19th International Conference on Advanced Information Networking and Applications - Volume 1 (2005)

With the rapid development of Internet technology and Web-based education, distance learning provides a novel learning style, which is different from traditional education. In order to adapt different teaching strategies in accordance to individual studentsý abilities in a distance learning environment, system directed navigation of students was proposed in a distance learning standard called SCORM (Sharable Content Object Reference Model). We introduce the Distance-learning Color Petri Net (DCPN), applying the features of Petri nets, to decrease the complexity of the sequencing definition model in the SCORM 2004 specification. We thus construct a sequencing framework for various instructional strategies by piecing DPCN subnets together.
Dynamic coast control of train movement with genetic algorithm
Authors: K. K. Wong, T. K. Ho
Venue: International Journal of Systems Science (2004)

The railway service is now the major transportation means in most of the countries around the world. With the increasing population and expanding commercial and industrial activities, a high quality of railway service is the most desirable. Train service usually varies with the population activities throughout a day and train coordination and service regulation are then expected to meet the daily passengers' demand. Dwell time control at stations and fixed coasting point in an inter-station run are the current practices to regulate train service in most metro railway systems. However, a flexible and efficient train control and operation is not always possible. To minimize energy consumption of train operation and make certain compromises on the train schedule, coast control is an economical approach to balance run-time and energy consumption in railway operation if time is not an important issue, particularly at off-peak hours. The capability to identify the starting point for coasting according to the current traffic conditions provides the necessary flexibility for train operation. This paper presents an application of genetic algorithms (GA) to search for the appropriate coasting point(s) and investigates the possible improvement on fitness of genes. Single and multiple coasting point control with simple GA are developed to attain the solutions and their corresponding train movement is examined. Further, a hierarchical genetic algorithm (HGA) is introduced here to identify the number of coasting points required according to the traffic conditions, and Minimum-Allele-Reserve-Keeper (MARK) is adopted as a genetic operator to achieve fitter solutions.
Spatiotemporal Annotation Graph (STAG): A Data Model for Composite Digital Objects
Authors: Smriti Yamini, Amarnath Gupta
Venue: Proceedings of the 21st International Conference on Data Engineering (2005)

In this demonstration, we present a database over complex documents, which, in addition to a structured text content, also has update information, annotations, and embedded objects. We propose a new data model called Spatio-temporal Annotation Graphs (STAG) for a database of composite digital objects and present a system that shows a query language to efficiently and effectively query such database. The particular application to be demonstrated is a database over annotated MS Word and PowerPoint presentations with embedded multimedia objects.
Waypoint navigation with a vibrotactile waist belt
Authors: Jan B. F. Van Erp, Hendrik A. H. C. Van Veen, Chris Jansen, Trevor Dobbins
Venue: ACM Transactions on Applied Perception (TAP) (2005)

Presenting waypoint navigation on a visual display is not suited for all situations. The present experiments investigate if it is feasible to present the navigation information on a tactile display. Important design issue of the display is how direction and distance information must be coded. Important usability issues are the resolution of the display and its usefulness in vibrating environments. In a pilot study with 12 pedestrians, different distance-coding schemes were compared. The schemes translated distance to vibration rhythm while the direction was translated into vibration location. The display consisted of eight tactors around the user's waist. The results show that mapping waypoint direction on the location of vibration is an effective coding scheme that requires no training, but that coding for distance does not improve performance compared to a control condition with no distance information. In Experiment 2, the usefulness of the tactile display was shown in two case studies with a helicopter and a fast boat.
Designing mediation for context-aware applications
Authors: Anind K. Dey, Jennifer Mankoff
Venue: ACM Transactions on Computer-Human Interaction (TOCHI) (2005)

Many context-aware services make the assumption that the context they use is completely accurate. However, in reality, both sensed and interpreted context is often ambiguous. A challenge facing the development of realistic and deployable context-aware services, therefore, is the ability to handle ambiguous context. Although some of this ambiguity may be resolved using automatic techniques, we argue that correct handling of ambiguous context will often need to involve the user. We use the term mediation to refer to the dialogue that ensues between the user and the system. In this article, we describe an architecture that supports the building of context-aware services that assume context is ambiguous and allows for mediation of ambiguity by mobile users in aware environments. We present design guidelines that arise from supporting mediation over space and time, issues not present in the graphical user interface domain where mediation has typically been used in the past. We illustrate the use of our architecture and evaluate it through an example context-aware application, a word predictor system.
Testing versus estimation of graph properties
Authors: Eldar Fischer, Ilan Newman
Venue: Proceedings of the thirty-seventh annual ACM symposium on Theory of computing (2005)

The topic of tolerant property testing, that of distinguishing input instances that are far from satisfying a property from those that are close enough to satisfying it (as opposed to distinguishing the far instances only from the satisfying instances), has recently become an active topic of research in the field of combinatorial property testing [13]. In the general setting, there exist properties that are testable but not tolerantly testable [10]. However, we show here that in the setting of the dense graph model, all testable properties are not only tolerantly testable, but also admit a constant query size algorithm that estimates the distance from the property up to any fixed additive constant.In the course of the construction of this algorithm we develop a framework for extending Szemerédi's Regularity Lemma, both as a prerequisite for formulating what kind of information about the input graph will provide us with the correct estimation, and as the means for efficiently gathering this information. This work is also connected to the question of finding a combinatorial characterization of the testable graph properties, and to the question of efficiently finding a regular partition.
A Framework for Self-Management of Hybrid Wireless Networks Using Autonomic Computing Principles
Authors: Chong Shen, Dirk Pesch, James Irvine
Venue: Proceedings of the 3rd Annual Communication Networks and Services Research Conference (2005)

The dramatic increase in the number of mobile subscribers has put a significant resource and service provisioning strain on current cellular networks in particular in terms of multimedia and high-data rate service provision. Hybrid wireless networks, which is a novel scalable and adaptive wireless network architecture utilizing a mixture of cellular and ad hoc multi-hop routing, facilitates cellular network design with small cell systems without having to wire a large number of base stations into a core network. However, this new network design has drawbacks in terms of routing complexity, radio resource heterogeneity and network infrastructure design growth. Traditional centralised system administration methods become too inflexible to result in an manageable cellular system. A recently introduced concept - Autonomic Computing, based on stimulation from biological systems, may provide a remedy to the state of unmanageability. The Autonomic computing paradigm, recently coined autonomic communications, when applied to communication systems and networks, enables self-management, which is composed of self-protecting, self-healing, self-configuring and self-optimizing components. This self-management is not necessarily novel as technologies such as neural networks, fuzzy logic, genetic algorithms and evolutional methods have already been proposed to facilitate limited self-configuration and self-optimization when embedded with cellular and ad hoc networks. However, a structure or framework has been lacking so far. In this paper we propose an architecture for a framework of autonomic computing based on policies for a hybrid wireless network and investigate the merits of each of its functions.
PageRank and Interaction Information Retrieval: Research Articles
Authors: Sándor Dominich, Adrienn Skrop
Venue: Journal of the American Society for Information Science and Technology (2005)

The PageRank method is used by the Google Web search engine to compute the importance of Web pages. Two different views have been developed for the interpretation of the PageRank method and values: (a) stochastic (random surfer): the PageRank values can be conceived as the steady-state distribution of a Markov chain, and (b) algebraic: the PageRank values form the eigenvector corresponding to eigenvalue 1 of the Web link matrix. The Interaction Information Retrieval (I2R) method is a nonclassical information retrieval paradigm, which represents a connectionist approach based on dynamic systems. In the present paper, a different interpretation of PageRank is proposed, namely, a dynamic systems viewpoint, by showing that the PageRank method can be formally interpreted as a particular case of the Interaction Information Retrieval method; and thus, the PageRank values may be interpreted as neutral equilibrium points of the Web. &copy; 2005 Wiley Periodicals, Inc.
A network flow algorithm to minimize beam-on time for unconstrained multileaf collimator problems in cancer radiation therapy
Authors: Ravindra K. Ahuja, Horst W. Hamacher
Venue: Networks (2005)

In this article, we study the modulation of intensity matrices arising in cancer radiation therapy using multileaf collimators. This problem can be formulated by decomposing a given m &times; n integer matrix into a positive linear combination of &lpar;0, 1&rpar; matrices with the strict consecutive 1's property in rows. We consider a special case in which no technical constraints have to be taken into account. In this situation, the rows of the intensity matrix are independent of each other and the problem is equivalent to decomposing m intensity rows&mdash;independent of each other&mdash;into positive linear combinations of &lpar;0, 1&rpar; rows with the consecutive 1's property. We demonstrate that this problem can be transformed into a minimum cost flow problem in a directed network that has the following special structures: &lpar;1&rpar; the network is acyclic; &lpar;2&rpar; it is a complete graph &lpar;that is, there is an arc &lpar;i, j&rpar; whenever i < j&rpar;; &lpar;3&rpar; each arc cost is 1; and &lpar;4&rpar; each arc is uncapacitated &lpar;that is, it has infinite capacity&rpar;. We show that using this special structure, the minimum cost flow problem can be solved in O&lpar;n&rpar; time. Because we need to solve m such problems, the total running time of our algorithm is O&lpar;nm&rpar;, which is an optimal algorithm to decompose a given m &times; n integer matrix into a positive linear combination of &lpar;0, 1&rpar; matrices. &copy; 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 45&lpar;1&rpar;, 36&ndash;41 2005
Explicit inverse of a tridiagonal k&#x2212;Toeplitz matrix
Authors: C. M. da Fonseca, J. Petronilho
Venue: Numerische Mathematik (2005)

We obtain explicit formulas for the entries of the inverse of a nonsingular and irreducible tridiagonal k&#x2212;Toeplitz matrix A. The proof is based on results from the theory of orthogonal polynomials and it is shown that the entries of the inverse of such a matrix are given in terms of Chebyshev polynomials of the second kind. We also compute the characteristic polynomial of A which enables us to state some conditions for the existence of A&#x2212;1. Our results also extend known results for the case when the residue mod k of the order of A is equal to 0 or k&#x2212;1 (Numer. Math., 10 (1967), pp. 153&#x2013;161.).
Fine-grained network time synchronization using reference broadcasts
Authors: Jeremy Elson, Lewis Girod, Deborah Estrin
Venue: Proceedings of the 5th symposium on Operating systems design and implementationDue to copyright restrictions we are not able to make the PDFs for this conference available for downloading (2002)

Recent advances in miniaturization and low-cost, low-power design have led to active research in large-scale networks of small, wireless, low-power sensors and actuators. Time synchronization is critical in sensor networks for diverse purposes including sensor data fusion, coordinated actuation, and power-efficient duty cycling. Though the clock accuracy and precision requirements are often stricter than in traditional distributed systems, strict energy constraints limit the resources available to meet these goals.We present Reference-Broadcast Synchronization, a scheme in which nodes send reference beacons to their neighbors using physical-layer broadcasts. A reference broadcast does not contain an explicit timestamp; instead, receivers use its arrival time as a point of reference for comparing their clocks. In this paper, we use measurements from two wireless implementations to show that removing the sender's nondeterminism from the critical path in this way produces high-precision clock agreement (1.85&plusmn; 1.28&mu;sec, using off-the-shelf 802.11 wireless Ethernet), while using minimal energy. We also describe a novel algorithm that uses this same broadcast property to federate clocks across broadcast domains with a slow decay in precision (3.68&plusmn; 2.57&mu;sec after 4 hops). RBS can be used without external references, forming a precise relative timescale, or can maintain microsecond-level synchronization to an external timescale such as UTC. We show a significant improvement over the Network Time Protocol (NTP) under similar conditions.
Pricing in publish/subscribe systems
Authors: Andreas Tanner, Michael A. Jaeger
Venue: Proceedings of the 6th international conference on Electronic commerce (2004)

Publish/subscribe systems have gained increasing interest in the past few years. There are many commercial products available today that rely on them directly. However, up to now there has been no discussion about pricing in such systemsWe present a new strategyproof distributed algorithm that calculates the maximum subtree of the broker network and the costs arising for the clients. These payments sum up to the amount defined by the marginal cost mechanism and maximize the social surplus (i.e. the sum of the utilities minus the costs). It is taken into account that there may be multiple publishers serving one filter. An extended self-stabilized version copes with systems whose structure underlies a permanent change when publishers (dis-) appear and client utility changes. An adjustment is presented that considers different rates for subscriptions and therefore weakens the previous all-or-nothing scenario.
Impedance characteristics of power distribution grids in nanoscale integrated circuits
Authors: Andrey V. Mezhiba, Eby G. Friedman
Venue: IEEE Transactions on Very Large Scale Integration (VLSI) Systems (2004)

The essential design characteristic of nanoscale integrated circuits is increased interconnect complexity. Conductors at different levels of the interconnect hierarchy have highly different physical and, consequently, electrical characteristics. These interconnect lines also exhibit inductive behavior due to enhanced switching speed of nanoscale devices, making interconnect design and analysis difficult. The design of robust and area efficient power distribution networks for high-speed integrated circuits has therefore become a challenging task. The impedance characteristics of multilayer power distribution grids and the relevant design implications are the subject of this paper. The power distribution network spans many layers of interconnect with disparate electrical properties. Unlike single-layer grids, the electrical characteristics of multilayer grids vary significantly with frequency. As the frequency increases, a large share of the current flow is transfered from the low-resistance upper layers to the low-inductance lower layers. The inductance of a multilayer grid therefore decreases with frequency, while the resistance increases with frequency. The lower layers of multilayer power grids provide a low-inductance current path, significantly reducing the grid impedance at high frequencies. Multilayer power distribution grids extend to the lower interconnect layers, exhibiting superior high-frequency impedance characteristics as compared to power distribution grids built exclusively within the upper, low-resistance metal layers. A significant share of metal resources to distribute the global power should therefore be allocated to the lower metal layers. An analytic model is also presented to determine the impedance characteristics of a multilayer grid from the inductive and resistive properties of the comprising individual grid layers.
Preventing type flaw attacks on security protocols with a simplified tagging scheme
Authors: Yafen Li, Wuu Yang, Ching-Wei Huang
Venue: Proceedings of the 2004 international symposium on Information and communication technologies (2004)

A type flaw attack on a security protocol is an attack where a field in a message that was originally intended to have one type is subsequently interpreted as having another type. Heather et al. proves that type flaw attacks can be prevented with the technique of tagging each field with the information that indicates its intended type. We simplify Heather et al.'s tagging scheme by combining all the tags inside each encrypted component into a single tag and by omitting the tags on the outmost level. The simplification reduces the sizes of messages in the security protocol. We also formally prove our simplified tagging scheme is as secure as Heather et al.'s with the strand space method. Note that Heather et al.'s tagging scheme and our simplified tagging are applicable to, not just one protocol, but a variety of security protocols.
estWin: Online data stream mining of recent frequent itemsets by sliding window method
Authors: Joong Hyuk Chang, Won Suk Lee
Venue: Journal of Information Science (2005)

Knowledge embedded in a data stream is likely to be changed as time goes by. Identifying the recent change of the knowledge quickly can provide valuable information for the analysis of the data stream. However, most mining algorithms over a data stream are not able to extract the recent change of knowledge in a data stream adaptively. This is because the obsolete information of old data elements which may be no longer useful or possibly invalid at present is regarded as being as important as that of recent data elements. This paper proposes a sliding window method that finds recently frequent itemsets over a transactional online data stream adaptively. The size of a sliding window defines the desired life-time of information in a newly generated transaction. Consequently, only recently generated transactions in the range of the window are considered to find the recently frequent itemsets of a data stream.
On the Low-Rank Approximation of Data on the Unit Sphere
Authors: M. Chu, N. Del Buono, L. Lopez, T. Politi
Venue: SIAM Journal on Matrix Analysis and Applications (2005)

In various applications, data in multidimensional space are normalized to unit length. This paper considers the problem of best fitting given points on the m-dimensional unit sphere Sm-1 by k-dimensional great circles with k much less than m. The task is cast as an algebraically constrained low-rank matrix approximation problem. Using the fidelity of the low-rank approximation to the original data as the cost function, this paper offers an analytic expression of the projected gradient which, on one hand, furnishes the first order optimality condition and, on the other hand, can be used as a numerical means for solving this problem.
Network-based Intrusion Detection-Modeling for a Larger Picture
Venue: Proceedings of the 16th USENIX conference on System administration (2002)

The Internet is changing computing more than ever before. As the possibilities and the scopes are limitless, so too are the risks and chances of malicious intrusions. Due to the increased connectivity and the vast spectrum of financial possibilities, more and more systems are subject to attack by intruders. One of the commonly used method for intrusion detection is based on anomaly. Network based attacks may occur at various levels, from application to link levels. So the number of potential attackers or intruders are extremely large and thus it is almost impossible to "profile" entities and detect intrusions based on anomalies in host-based profiles. Based on meta-information, logical groupings has been made for the alerts that belongs to same logical network, to get a clearer and boarder view of the perpetrators. To reduce the effect of probably insignificant alerts a threshold technique is used.
Constructing extensible XQuery mappings
Authors: Gang Qian, Yisheng Dong
Venue: Special interest tracks and posters of the 14th international conference on World Wide Web (2005)

Constructing and maintaining semantic mappings are necessary but troublesome in data sharing systems. While most current work focuses on seeking automated techniques to solve this problem, this paper proposes a combination model for constructing exten-sible mappings between XML schemas. In our model, complex global mappings are constructed by first defining simple atomic mappings for each target schema element, and then combining them using a few basic operators. At the same time, we provide automated support for constructing such combined mappings.
Similarity Searching in Peer-to-Peer Databases
Authors: Indrajit Bhattacharya, Srinivas R. Kashyap, Srinivasan Parthasarathy
Venue: Proceedings of the 25th IEEE International Conference on Distributed Computing Systems (2005)

We consider the problem of handling similarity queries in peer-to-peer databases. We propose an indexing and searching mechanism which, given a query object, returns the set of objects in the database that are semantically related to the query. We propose an indexing scheme which clusters data such that semantically related objects are partitioned into a small set of clusters, allowing for a simple and efficient similarity search strategy. Our indexing scheme also decouples object and node locations. Our adaptive replication and randomized lookup schemes exploit this feature and ensure that the number of copies of an object is proportional to its popularity and all replicas are equally likely to serve a given query, thus achieving perfect load balancing. The techniques developed in this work are oblivious to the underlying DHT topology and can be implemented on a variety of structured overlays such as CAN, CHORD, Pastry, and Tapestry. We also present DHT-independent analytical guarantees for the performance of our algorithms in terms of search accuracy, cost, and load-balance; the experimental results from our simulationsconfirm the insights derived from these analytical models.