ppxscal/embedding_network huggingface dataset:
Eventual Clusterer: A Modular Approach to Designing Hierarchical Consensus Protocols in MANETs
Authors: Weigang Wu, Jiannong Cao, Michel Raynal
Venue: IEEE Transactions on Parallel and Distributed Systems (2009)

This paper proposes a modular approach to the design of hierarchical consensus protocols for the mobile ad hoc network with a static and known set of hosts. A two-layer hierarchy is imposed on the network by grouping mobile hosts into clusters, each with a clusterhead. The messages from and to the hosts in the same cluster are merged/unmerged by the clusterhead so as to reduce the message cost and improve the scalability. The proposed modular approach separates the concerns of clustering hosts from achieving consensus. A clustering function, called eventual clusterer (denoted as \diamondC), is designed for constructing and maintaining the two-layer hierarchy. Similar to unreliable failure detectors, \diamondC greatly facilitates the design of hierarchical protocols by providing the fault-tolerant clustering function transparently. We propose an implementation of \diamondC based on the failure detector \diamondS. Using \diamondC, we design a new hierarchical consensus protocol. As shown by the performance evaluation results, the proposed consensus protocol can save both message cost and time cost. Our proposed modular design is therefore effective and can lead to efficient solutions to achieving consensus in mobile ad hoc networks.
Mutual coupling, channel model, and ber for curvilinear antenna arrays
Authors: Zhiyong Huang
Venue:  (2008)

This dissertation introduces a wireless communications system with an adaptive beam-former and investigates its performance with different antenna arrays. Mutual coupling, real antenna elements and channel models are included to examine the system performance. In a beamforming system, mutual coupling (MC) among the elements can significantly degrade the system performance. However, MC effects can be compensated if an accurate model of mutual coupling is available. A mutual coupling matrix model is utilized to compensate mutual coupling in the beamforming of a uniform circular array (UCA). Its performance is compared with other models in uplink and downlink beamforming scenarios. In addition, the predictions are compared with measurements and verified with results from full-wave simulations. In order to accurately investigate the minimum mean-square-error (MSE) of an adaptive array in MC, two different noise models, the environmental and the receiver noise, are modeled. The minimum MSEs with and without data domain MC compensation are analytically compared. The influence of mutual coupling on the convergence is also examined. In addition, the weight compensation method is proposed to attain the desired array pattern. Adaptive arrays with different geometries are implemented with the minimum MSE algorithm in the wireless communications system to combat interference at the same frequency. The bit-error-rate (BER) of systems with UCA, uniform rectangular array (URA) and UCA with center element are investigated in additive white Gaussian noise plus well-separated signals or random direction signals scenarios. The output SINR of an adaptive array with multiple interferers is analytically examined. The influence of the adaptive algorithm convergence on the BER is investigated. The UCA is then investigated in a narrowband Rician fading channel. The channel model is built and the space correlations are examined. The influence of the number of signal paths, number of the interferers, Doppler spread and convergence are investigated. The tracking mode is introduced to the adaptive array system, and it further improves the BER. The benefit of using faster data rate (wider bandwidth) is discussed. In order to have better performance in a 3D space, the geometries of uniform spherical array (USAs) are presented and different configurations of USAs are discussed. The LMS algorithm based on temporal a priori information is applied to UCAs and USAs to beamform the patterns. Their performances are compared based on simulation results. Based on the analytical and simulation results, it can be concluded that mutual coupling slightly influences the performance of the adaptive array in communication systems. In addition, arrays with curvilinear geometries perform well in AWGN and fading channels. 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
Grid Application Systems Design, 1st edition
Authors: April J. Wells
Venue:  (2007)

Grid computing is an emerging technology designed for high-powered applications. Grid Application Systems Design shows how to unleash the high performance of Grid technology. It begins by delving into the history and theory of grid computing, providing background on the concepts, terminology, and issues surrounding it. The book then examines design issues inherent in using Grid technology and a highly distributed computing model. These issues include data updating, data retrieval, concurrency, maintenance, and security concerns. The book also takes an in-depth look at the advantages of migrating toward this new computing architecture and the possibilities it holds for users. The author addresses such issues as high capacity bandwidth and interconnection requirements that relate to managers and administrators. Lastly, the book explores the design decisions, issues, and opportunities that must be tackled by the designer, the developer, and the data administrator involved in creating applications for this new paradigm. 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
Source localization using electric and magnetic point dipoles with modified genetic algorithm
Authors: Päivi K. Koivisto, Johan C.-E. Sten
Venue: International Journal of Numerical Modelling: Electronic Networks, Devices and Fields (2009)

A method to reconstruct the source current from far-field data in terms of electric and magnetic point dipoles is described. The inverse problem of solving the source from a known electromagnetic far-field pattern is carried out by a combination of genetic algorithm and local optimizers. The source is modelled by a small number of point dipoles, the locations, amplitudes and types of which are determined by minimizing the difference between the field of the ensemble and the targeted pattern. Uniqueness is ensured by limiting the number of dipoles together with an appropriately weighted minimum energy condition. A general description of the method applicable to antenna analysis and synthesis is given and three examples of its practical use are presented. Copyright &copy; 2008 John Wiley & Sons, Ltd.
Query-based requirements engineering for health care information systems: Examples and prospects
Authors: Oystein Nytro, Inger Dybdahl Sorby, Peter Karpati
Venue: Proceedings of the 2009 ICSE Workshop on Software Engineering in Health Care (2009)

Designing healthcare information systems is a challenge to software engineering theory and practice. Many requirements engineering (RE) methods demand user-participation, clear functional objectives and a well defined context of use. These demands are hard to meet in the healthcare domain, which is characterized by high diversity, complexity and little time and money to spend. There are many examples of healthcare software systems that have failed due to lacking investment in the early phases of design and requirements analysis. We have developed methods for gathering detailed observational data about care and communication practice. In this article, we explain how this data can be used for iterative, demand-driven, requirements elicitation and to answer design questions. The examples are taken from structured observation of actors, situations, information usage and activities at two Norwegian hospitals. We regard this approach as a useful supplement to other RE methods, in particular for agile development methods.
Optimal strategies in sequential bidding
Authors: Krzysztof R. Apt, Evangelos Markakis
Venue: Proceedings of The 8th International Conference on Autonomous Agents and Multiagent Systems - Volume 2 (2009)

We are interested in mechanisms that maximize the final social welfare. In [1] this problem was studied for multi-unit auctions with unit demand bidders and for the public project problem, and in each case social welfare undominated mechanisms in the class of feasible and incentive compatible mechanisms were identified.
Circular spline fitting using an evolution process
Authors: Xinghua Song, Martin Aigner, Falai Chen, Bert Jüttler
Venue: Journal of Computational and Applied Mathematics (2009)

We propose a new method to approximate a given set of ordered data points by a spatial circular spline curve. At first an initial circular spline curve is generated by biarc interpolation. Then an evolution process based on a least-squares approximation is applied to the curve. During the evolution process, the circular spline curve converges dynamically to a stable shape. Our method does not need any tangent information. During the evolution process, the number of arcs is automatically adapted to the data such that the final curve contains as few arc arcs as possible. We prove that the evolution process is equivalent to a Gauss-Newton-type method.
Inter-cluster routing authentication for ad hoc networks by a hierarchical key scheme
Authors: Yueh-Min Huang, Hua-Yi Lin, Tzone-I Wang
Venue: Journal of Computer Science and Technology (2006)

Dissimilar to traditional networks, the features of mobile wireless devices that can actively form a network without any infrastructure mean that mobile ad hoc networks frequently display partition due to node mobility or link failures. These indicate that an ad hoc network is difficult to provide on-line access to a trusted authority server. Therefore, applying traditional Public Key Infrastructure (PKI) security framework to mobile ad hoc networks will cause insecurities. This study proposes a scalable and elastic key management scheme integrated into Cluster Based Secure Routing Protocol (CBSRP) to enhance security and non-repudiation of routing authentication, and introduces an ID-Based internal routing authentication scheme to enhance the routing performance in an internal cluster. Additionally, a method of performing routing authentication between internal and external clusters, as well as inter-cluster routing authentication, is developed. The proposed cluster-based key management scheme distributes trust to an aggregation of cluster heads using a threshold scheme faculty, provides Certificate Authority (CA) with a fault tolerance mechanism to prevent a single point of compromise or failure, and saves CA large repositories from maintaining member certificates, making ad hoc networks robust to malicious behaviors and suitable for numerous mobile devices.
Torrent worms
Authors: Constantinos Patsakis, Nikolaos Alexandris
Venue: Proceeding of the 2008 conference on Knowledge-Based Software Engineering: Proceedings of the Eighth Joint Conference on Knowledge-Based Software Engineering (2008)

One of the most widely used peer-to-peer file sharing protocols is BitTorrent. In this article we focus on the possible use of bittorrent protocol and applications that make use it, as platform for the spread of new computer-worms.
Decentralised dynamic task allocation: a practical game: theoretic approach
Authors: Archie C. Chapman, Rosa Anna Micillo, Ramachandra Kota, Nicholas R. Jennings
Venue: Proceedings of The 8th International Conference on Autonomous Agents and Multiagent Systems - Volume 2 (2009)

This paper reports on a novel decentralised technique for planning agent schedules in dynamic task allocation problems. Specifically, we use a Markov game formulation of these problems for tasks with varying hard deadlines and processing requirements. We then introduce a new technique for approximating this game using a series of static potential games, before detailing a decentralised solution method for the approximating games that uses the Distributed Stochastic Algorithm. Finally, we discuss an implementation of our approach to a task allocation problem in the RoboCup Rescue disaster management simulator. Our results show that our technique performs comparably to a centralised task scheduler (within 6% on average), and also, unlike its centralised counterpart, it is robust to restrictions on the agents' communication and observation range.
Iterated local search for the multiple depot vehicle scheduling problem
Authors: Benoít Laurent, Jin-Kao Hao
Venue: Computers and Industrial Engineering (2009)

The multiple depot vehicle scheduling problem (MDVSP) is a well-known and important problem arising in public transport. Although many solution approaches have been published in the literature, algorithms using metaheuristics appeared only very recently (large neighborhood search and Tabu search). In this paper, we introduce an iterated local search algorithm for the MDVSP, incorporating a neighborhood schema called ''block moves'', based on the notion of ejection chains. Using a set of benchmark instances, we show empirically that the proposed algorithm performs better than the best metaheuristics implemented so far and obtains high quality results within short computational times.
Reusing and Composing Habitual Behavior in Video Browsing
Authors: Akio Takashima, Yuzuru Tanaka
Venue: Proceeding of the 2008 conference on Information Modelling and Knowledge Bases XIX (2008)

We have increasingly more opportunities to use video for our knowledge work, such as monitoring events, reflecting on physical performances, learning subject matter, or analyzing scientific experimental phenomena. In such ill-defined situation, users often create their own browsing styles to explore the videos because the domain knowledge of contents is not useful, and then the users interact with videos according to their browsing style. However, such kind of tacit knowledge, which is acquired through user's experiences, has not been well managed. The goal of our research is to share and reuse tacit knowledge, and then create new knowledge by composing them in video browsing. This paper describes the notion of reusing habitual behavior of video browsing, and presents examples of composing these behaviors to create new video browsing styles.
MINCE A Framework for Organizational Maturity
Authors: Van Harern Publishing
Venue: Best Practice Series (2007)

Assessment of Organizational Maturity is becoming a very popular technique. This book explains how most organizations need to achieve and maintain the competitive ability to meet and take advantage of change. Skills, technical ability, processes all must be in place to achieve competitive advantage. Many companies aspire to maturity in these areas; others use well documented and successful frameworks and approaches in specific areas of the organization. However it is clear that maturity and all the benefits it delivers cannot be limited to just one department in an organization or just one discipline. MINCE, a framework for achieving organizational maturity, takes the approach that maturity is in effect the sum total of a corporation expressed in terms of the people within it and how they deliver regardless of whether the requirement is HR, technical, Customer Service or Governance. MINCE therefore describes an overall approach to maturity; the advantage is that organizations can finally identify and assess their ability to deliver change in terms of their overall ability in other words how their customers see it. MINCE identifies six pillars of maturity: 1. People 2. Methods and techniques 3. Customer 4. Realization 5. Knowledge 6. Supporting Services These pillars can be assessed across departments and across organizations using the following criteria: A. Leadership B. Staff C. Policy D. Means E. Instructions Depending on the nature of the business organizations one can decide how important these pillars are and how much to invest in order to improve the maturity scores. As soon as the organization starts using the MINCE measurement toolset, management will gain insights in: maturity of the organization; skills of the staff; abilities of the organization s customer chain; effectiveness of the organization s projects; the way the organization benefits from past lessons learned, and ability to adapt to change. Organizations are not simple; if they were, assessment and implementation of change wouldn t be as difficult as they so clearly are for many. MINCE takes the complex mix of people skills, process approach and technical ability and describes a common-sense and easy to understand approach that is relevant for all. Its well thought-out approach provide a much needed solution to many organizations seeking to make the leap from a simple silo delivery to real organizational achievement. 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
Five Levels of Collaboration --Five Levels of ICT Support?
Authors: Heini Korpilahti, Toni Koskinen
Venue: Proceeding of the 2006 conference on Cooperative Systems Design: Seamless Integration of Artifacts and Conversations -- Enhanced Concepts of Infrastructure for Communication (2006)

The research work presented in this paper employs the awareness evaluation model developed by Neale, Carrol, and Rosson [1]. The model presents five collaboration levels based on how closely the tasks of different persons are coupled together. These levels are light-weight interaction, information sharing, coordination, collaboration, and cooperation. We applied the model in distributed process industry environment. Our goal was to identify the existing collaboration situations and place them to different categories of the model. In addition, we viewed these different collaboration levels from the standpoint ICT-mediated collaboration support. This meant that we identified both the requirements for ICT-mediated collaboration support and applications capable of fulfilling the requirements set by the interaction situations. As a result we noticed that one of the characteristics of interaction situations classified into these categories is a constant switching of collaboration levels. By this we mean that during interaction situations people are seamlessly shifting from one level to another. When reflecting this finding in ICT support, it seems to indicate that in the same way the support for higher collaboration levels should make possible seamless transitions from one level to another. More detailed results are presented in the paper.
A Dynamic Theory of Ontology
Authors: John F. Sowa
Venue: Proceeding of the 2006 conference on Formal Ontology in Information Systems: Proceedings of the Fourth International Conference (FOIS 2006) (2006)

Natural languages are easy to learn by infants, they can express any thought that any adult might ever conceive, and they accommodate the limitations of human breathing rates and short-term memory. The first property implies a finite vocabulary, the second implies infinite extensibility, and the third implies a small upper bound on the length of phrases. Together, they imply that most words in a natural language will have an open-ended number of senses ---ambiguity is inevitable. Peirce and Wittgenstein are two philosophers who understood that vagueness and ambiguity are not defects in language, but essential properties that enable it to accommodate anything that people need to say. In analyzing the ambiguities, Wittgenstein developed his theory of language games, which allow words to have different senses in different contexts, applications, or modes of use. Recent developments in lexical semantics, which are remarkably compatible with the views of Peirce and Wittgenstein, are based on the recognition that words have an open-ended number of dynamically changing and context-dependent microsenses. The resulting flexibility enables natural languages to adapt to any possible subject from any perspective for any humanly conceivable purpose. To achieve a comparable level of flexibility with formal ontologies, this paper proposes an organization with a dynamically evolving collection of formal theories, systematic mappings to formal concept types and informal lexicons of natural language terms, and a modularity that allows independent distributed development and extension of all resources, formal and informal.
Creating Digital Resources from Legacy Documents: An Experience Report from the Biosystematics Domain
Authors: Guido Sautter, Klemens Böhm, Donat Agosti, Christiana Klingenberg
Venue: Proceedings of the 6th European Semantic Web Conference on The Semantic Web: Research and Applications (2009)

Digitized legacy document marked up with XML can be used in many ways, e.g., to generate RDF statements about the world described. A prerequisite for doing so is that the document markup is of sufficient quality. Since fully automated markup-generation methods cannot ensure this, manual corrections and cleaning are indispensable. In this paper, we report on our experiences from a digitization and markup project for a large corpus of legacy documents from the biosystematics domain, with a focus on the use of modern tools. The markup created covers both document structure and semantic details. In contrast to previous markup projects reported on in literature, our corpus consists of large publications that comprise many different semantic units, and the documents contain OCR noise and layout artifacts. A core insight is that digitization and automated markup on the one hand and manual cleaning and correction on the other hand should be tightly interleaved, and that tools supporting this integration yield a significant improvement.
Combining textual and structural analysis of software artifacts for traceability link recovery
Authors: Collin McMillan, Denys Poshyvanyk, Meghan Revelle
Venue: Proceedings of the 2009 ICSE Workshop on Traceability in Emerging Forms of Software Engineering (2009)

Existing methods for recovering traceability links among software documentation artifacts analyze textual similarities among these artifacts. It may be the case, however, that related documentation elements share little terminology or phrasing. This paper presents a technique for indirectly recovering these traceability links in requirements documentation by combining textual with structural information as we conjecture that related requirements share related source code elements. A preliminary case study indicates that our combined approach improves the precision and recall of recovering relevant links among documents as compared to stand-alone methods based solely on analyzing textual similarities.
Computational analysis of perfect-information position auctions
Authors: David Robert Martin Thompson, Kevin Leyton-Brown
Venue: Proceedings of the tenth ACM conference on Electronic commerce (2009)

Position auctions were widely used by search engines to sell keyword advertising before being well understood (and, indeed, studied) theoretically. To date, theorists have made significant progress, for example showing that a given auction is efficient or revenue-dominates a benchmark auction such as VCG. This paper augments that line of work, relying on computational equilibrium analysis. By computing Nash equilibria and calculating their expected revenue and social welfare, we can quantitatively answer questions that theoretical methods have not. Broadly, the questions we answer are: (1) How often do the theoretically predicted "good" (i.e., efficient, high-revenue) equilibria of GSP occur? (2) In models where GSP is known to be inefficient, how much welfare does it waste? We also use our data to examine the larger question of whether GSP is a good choice, compared with the alternatives.