ppxscal/embedding_network huggingface dataset:
A Fuzzy Petri Nets approach for railway traffic control in case of abnormality: Evidence from Taiwan railway system
Authors: Yung-Hsiang Cheng, Li-An Yang
Venue: Expert Systems with Applications: An International Journal (2009)

Railway traffic control by dispatchers in case of abnormality is critical to assure the service quality of a railway system's operation. However, this unique professional knowledge often lies in the dispatcher's mind. Therefore, this study aims to transform a train dispatcher's expertise into a useful knowledge rule. The fuzzy Petri Net approach is adopted to formulate the decision rules of train dispatchers in case of abnormality as the basis for future development of a dispatching decision support system. The dispatching decision rules, factors, and possible options when perturbation happens are collected via expert interviews and literature reviews. This study discusses the abnormal scenarios, including centralized traffic control system failure, automatic train protection failure, and locomotive failure. A case study of a line section of Taiwan's railway network is implemented and the empirical result could be used as a reference in railway dispatching in case of abnormality.
An efficient proxy raffle protocol with anonymity-preserving
Authors: Chin-Chen Chang, Ting-Fang Cheng
Venue: Computer Standards Interfaces (2009)

In 2005, Chen et al. implemented a proxy raffle scheme for the Internet. Unfortunately, their scheme is unable to withstand Denial of Service (DoS) and impersonation attacks. We consequently propose a novel version of this scheme, in this paper, which can resist these malicious attacks. The security of our scheme is based on symmetric and asymmetric cryptosystems. A timestamp mechanism is also applied to prevent suffering the replay attack. Specifically, the communication load of our scheme is less than that of Chen et al.'s scheme. Thus, we can implement our method for the Internet as well as mobile devices.
Supporting QoS in IEEE 802.11e wireless LANs over fading channel
Authors: Marzieh Varposhti, Naser Movahhedinia
Venue: Computer Communications (2009)

Transferring real-time traffic such as voice and video over wireless LAN networks (WLAN) requires stringent delay and jitter requirements. Recently IEEE 802.11e standard has been emerged to support QoS in WLAN. One of the methods to provide QoS in this standard is Enhanced Distributed Channel Access (EDCA) which benefits form the concept of traffic categories. However, EDCA is a contention based method; therefore it can not guarantee strict QoS required by real-time services without proper network control mechanisms. In this paper, we analyze the effect of loss and delay caused by fading channel on EDCA performance. Then, we propose a modification to the media access scheme, called CAFD (Collision Avoidance with Fading Detection) to elevate the performance against channel failures. Moreover an adjustment for the maximum number of retransmissions is proposed to maintain the delay and jitter requirements of the real-time traffic. The performances of the proposed methods are evaluated by simulations.
Inflatable XML processing
Authors: Rohit Fernandes, Mukund Raghavachari
Venue: Proceedings of the ACM/IFIP/USENIX 2005 International Conference on Middleware (2005)

The past few years have seen the widespread adoption of XML as a data representation format in various middleware: databases, Web Services, messaging systems, etc. One drawback of XML has been the high cost of XML processing. We present in this paper InflateX, a system that supports efficient XML processing. InflateX advances the state of the art in two ways. First, it uses a novel representation of XML, called inflatable trees, that supports lazy construction of an XML document in-memory in response to client requests, as well as, more efficient serialization of results. Second, it incorporates a novel algorithm, based on the idea of projection [8], for efficiently constructing an inflatable tree given a set of XPath expressions. The projection algorithm presented in this paper, unlike previous work, can handle all axes in XPath, including complex axes such as ancestor. While we describe the algorithm in terms of our inflatable tree representation, it is portable to other representations of XML. We provide experiments that validate the utility of our inflatable tree representation and our projection algorithm.
The business value of information technology as measured by technical efficiency: Evidence from country-level data
Authors: Winston T. Lin
Venue: Decision Support Systems (2009)

The value of information technology (IT) in a business production process has long been a debatable issue. Explanation of the so-called ''productivity paradox'' has been one of the central topics in this arena. Much work has focused on firm-level analyses. This paper investigates IT contribution at a country level, using production theory in microeconomics. It negates the relationship between IT value and productivity based on grouping of countries, when the individual analytical method is applied and technical efficiency is used as the performance criterion. Findings obtained by applying stochastic production frontiers to a comprehensive country-level panel data set suggest that the IT contributions, as determined by the increase or decrease in the technical efficiency, to individual countries differ in magnitude from a production frontier to another, but are robust. It also shows that IT spending does not necessarily improve technical efficiencies of individual countries, regardless of whether they are developed or developing countries, and that given technological changes, the so-called productivity paradox may exist in a country, no matter whether it is a developed or developing nation. Finally, the significant implications of the findings are presented.
Metascheduling Multiple Resource Types using the MMKP
Authors: Daniel Vanderster, Nikitas Dimopoulos, Randall Sobie
Venue: Proceedings of the 7th IEEE/ACM International Conference on Grid Computing (2006)

Grid computing involves the transparent sharing of computational resources of many types by users across large geographic distances. The altruistic nature of many current grid resource contributions does not encourage efficient usage of resources. As grid projects mature, increased resource demands coupled with increased economic interests will introduce a requirement for a metascheduler that improves resource utilization, allows administrators to define allocation policies, and provides an overall quality of service to the grid users. In this work we present one such metascheduling framework, based on the multichoice multidimensional knapsack problem (MMKP). This strategy maximizes overall grid utility by selecting desirable options of each task subject to constraints of multiple resource types. We present the framework for the MMKP metascheduler and discuss a selection of allocation policies and their associated utility functions. The MMKP metascheduler and allocation policies are demonstrated using a grid of processor, storage, and network resources. In particular, a data transfer time metric is incorporated into the utility function in order to prefer task options with the lowest data transfer times. The resulting schedules are shown to be consistent with the defined policies.
On the Structure of Pānini's System
Authors: George Cardona
Venue: Sanskrit Computational Linguistics: First and Second International Symposia Rocquencourt, France, October 29-31, 2007 Providence, RI, USA, May 15-17, 2008 Revised Selected and Invited Papers (2009)

Pānini accounts for utterances through a derivational procedure that starts from meaning conditions involving actions, participants in actions, and other things that are related to each other. His derivational system thereby serves to form utterances of which words are a part, not isolated words that are then strung together to form utterances. Pānini's system is a continuum that starts from meaning and cooccurrence conditions that determine the introduction of affixes to bases in order to form initial strings and subsequently applies additional affixation and replacement rules to produce final strings. The system does not isolate morphology as a distinct component absolutely independent of syntax. Declensional and conjugational morphology are part of syntactic derivation, and derivational morphology is generally incorporated in the syntactic machinery. Primary derivational affixes are introduced in the course of syntactic derivation. In addition, secondary derivation affixes are regularly introduced after padas---terms that contain endings introduced in syntactic derivation---and not after mere bases in a separate morphological component. Further, composition takes place within the context of syntactic derivation; compounds are formed from related padas of initial strings, which involve number distinctions. Even the formation of certain items with feminine suffixes takes place within the syntactic machinery and not in a totally separate lexicon. Thus Pānini's derivational system is an integrated system accounting for utterances of Sanskrit; it lacks a sharp dichotomy between what western grammarians call syntax and morphology.
An optimal way to licence the radio spectrum
Authors: William Webb
Venue: Telecommunications Policy (2009)

Radio spectrum licences are generally specified in terms of the power a holder is allowed to transmit. However, if licences become flexible, allowing change of use and technology, then this licensing approach could result in significant interference between users. A new approach is proposed termed ''spectrum usage rights'' (SURs) which restricts the interference a licence holder is allowed to cause rather than the power they are allowed to transmit. This approach is shown to protect users against interference while providing the maximum flexibility possible and its implementation is discussed.
Designing a Mixed Training Method (Synchronous and Asynchronous) to Be Offered Online for the Development of Skills for Teachers in Training
Authors: Louise Sauvé, Louis Villardier, Wilfried Probst
Venue: Proceedings of the 2009 International Conference on Mobile, Hybrid, and On-line Learning (2009)

The current challenge for teachers and trainers is to change the way they teach by becoming competent to integrate ICTs into their traditional teaching methods. To our knowledge few studies, if any, have examined this integration into a continuous training process in the work place. This paper presents the problem, the objectives and the methodology of a study that aims to experiment with a mixed model of online training. Depending on the learning profile and the skills of the adult student in the workplace, this model provides a personalized level of synchronous presential teaching and asynchronous distance learning, as well as the creation of the learning objects of the Form@tion program and its virtual workshops.
Sequential triangle strip generator based on hopfield networks
Authors: Jiří Šíma, Radim Lněnička
Venue: Neural Computation (2009)

The important task of generating the minimum number of sequential triangle strips (tristrips) for a given triangulated surface model is motivated by applications in computer graphics. This hard combinatorial optimization problem is reduced to the minimum energy problem in Hopfield nets by a linear-size construction. In particular, the classes of equivalent optimal stripifications are mapped one to one to the minimum energy states reached by a Hopfield network during sequential computation starting at the zero initial state. Thus, the underlying Hopfield network powered by simulated annealing (i.e., Boltzmann machine), which is implemented in the program HTGEN, can be used for computing the semioptimal stripifications. Practical experiments confirm that one can obtain much better results using HTGEN than by a leading conventional stripification program FTSG (a reference stripification method not based on neural nets), although the running time of simulated annealing grows rapidly near the global optimum. Nevertheless, HTGEN exhibits empirical linear time complexity when the parameters of simulated annealing (i.e., the initial temperature and the stopping criterion) are fixed and thus provides the semioptimal offline solutions, even for huge models of hundreds of thousands of triangles, within a reasonable time.
A protocol for a new double-loop computer network and its implementation
Authors: S. Leventis, G. Papadopoulos, S. Koubias, J. Constantinides
Venue: Proceedings of the May 4-7, 1981, national computer conference (1981)

In this paper a new double-loop computer network is presented, as well as its hardware implementation. The proposed protocol permits simultaneous transfer of variable-length messages even between interfering segments of the network. Various concurrent transmissions can also take place with this protocol. These operations, together with a completely distributed control mechanism, make this new network capable of providing automatic traffic regulation. In addition, the reliability of the system is improved. The nodes of the network can be implemented by existing programmable LSI communication protocol controllers. This simple hardware implementation and the above capabilities make the proposed network very attractive for local networks with high traffic demands. In this paper a node realization, based on the 8085A microprocessor chips, is also presented. Every node consists basically of two SDLC Chips, one DMA controller and the Interrupt Controller.
Review: Audio quality assessment techniques-A review, and recent developments
Authors: Dermot Campbell, Edward Jones, Martin Glavin
Venue: Signal Processing (2009)

Assessing the perceptual quality of wideband audio signals is an important consideration in many audio and multimedia networks and devices. Examples of such multimedia technologies are: streaming audio over the Internet, Digital Radio Mondiale (DRM), Digital Audio Broadcasting (DAB), VoIP (Voice over Internet Protocol), mobile phones, as well as compression algorithms for digital audio. The International Telecommunications Union (ITU) standard for audio quality (BS.1387) is commonly referred to as perceptual evaluation of audio quality (PEAQ). PEAQ is currently the only available standardised method for the purpose of audio quality assessment. This paper includes a brief technical summary of the standardised PEAQ algorithm. Furthermore, this paper outlines recent advancements in the general area of audio quality assessment since the publication of the ITU standard, and discusses possible techniques, including some recent findings, that could be used to extend the applicability of PEAQ and improve the accuracy of the algorithm in assessing the quality of multimedia devices and systems.
Subdivision methods for solving polynomial equations
Authors: B. Mourrain, J. P. Pavone
Venue: Journal of Symbolic Computation (2009)

This paper presents a new algorithm for solving a system of polynomials, in a domain of R^n. It can be seen as an improvement of the Interval Projected Polyhedron algorithm proposed by Sherbrooke and Patrikalakis [Sherbrooke, E.C., Patrikalakis, N.M., 1993. Computation of the solutions of nonlinear polynomial systems. Comput. Aided Geom. Design 10 (5), 379-405]. It uses a powerful reduction strategy based on univariate root finder using Bernstein basis representation and Descarte's rule. We analyse the behavior of the method, from a theoretical point of view, shows that for simple roots, it has a local quadratic convergence speed and gives new bounds for the complexity of approximating real roots in a box of R^n. The improvement of our approach, compared with classical subdivision methods, is illustrated on geometric modeling applications such as computing intersection points of implicit curves, self-intersection points of rational curves, and on the classical parallel robot benchmark problem.
Combined regression models
Authors: Enrique Castillo, Carmen Castillo, Ali S. Hadi, José M. Sarabia
Venue: Computational Statistics (2009)

The goal of this paper is two-fold. First, new regression models obtained by combinations of the least squares (LS), minimax (MM), and the least sum of absolute deviations (LSAD) are proposed. Second, measures for assessing the influence of observations on the fitted models are suggested. The paper is interdisciplinary because the theory behind the proposed method draws from results in the operations research area. The methods are illustrated by their application to some examples and graphical illustrations are given.
An expert system prototype for designing natural gas cogeneration plants
Authors: José Alexandre Matelli, Edson Bazzo, Jonny Carlos da Silva
Venue: Expert Systems with Applications: An International Journal (2009)

Cogeneration plants are units that simultaneously produce electricity and useful heat from the same fuel. In such plants different components (prime movers, pumps, steam generators, etc.) are combined in order to meet electricity and useful heat loads requirements. The trend in cogeneration is to move toward more efficient and often more complex plants, so that their design requires an expressive amount of engineering expertise and time. In this work, it is presented an expert system prototype to support engineers in the conceptual and preliminary design phases of natural gas cogeneration plants, considering the loads related to electricity and saturated steam as design requirements. The prototype consists of a knowledge base composed of rules, object-oriented, component technical information and procedural functions. It is able to provide different designs for the same requirements, each of them containing plant diagram, components specifications and sizing, and explanations for each prototype decision. A case for a plant with demands as 15MW of electricity and 30 t/h of saturated steam at 8bar is presented.
Unrestricted wavelet synopses under maximum error bound
Authors: Chaoyi Pang, Qing Zhang, David Hansen, Anthony Maeder
Venue: Proceedings of the 12th International Conference on Extending Database Technology: Advances in Database Technology (2009)

Constructing Haar wavelet synopses under a given approximation error has many real world applications. In this paper, we take a novel approach towards constructing unrestricted Haar wavelet synopses under an error bound on uniform norm (L&infin;). We provide two approximation algorithms which both have linear time complexity and a (log N)-approximation ratio. The space complexities of these two algorithms are O (log N) and O (N) respectively. These two algorithms have the advantage of being both simple in structure and naturally adaptable for stream data processing. Unlike traditional approaches for synopses construction that rely heavily on examining wavelet coefficients and their summations, the proposed construction methods solely depend on examining the original data and are extendable to other findings. Extensive experiments indicate that these techniques are highly practical and surpass related ones in both efficiency and effectiveness.
Amplify-and-forward cooperative diversity wireless networks: model, analysis, and monotonicity properties
Authors: Teerawat Issariyakul, Vikram Krishnamurthy
Venue: IEEE/ACM Transactions on Networking (TON) (2009)

This paper models and analyzes the performance of an amplify-and-forward cooperative diversity wireless network. We propose a Markov-based model, which encompasses the following aspects: 1) the transmission using amplify-and-forward cooperative diversity at the physical layer; 2) a flow control pro-tocol, finite and infinite transmitting buffers, and an ARQ-based error recovery mechanism at the radio link layer; and 3) a bursty traffic pattern at the application layer. We derive expressions for packet delivery probability and distribution of packet delivery delay. We numerically quantify improvement in terms of packet delivery probability and packet delivery delay for increasing SNR and/or cooperative nodes. For an additional cooperative node, we quantify the amount of SNR which can be reduced (i.e., SNR saving) without degrading the system performance. Also, the minimum SNR and cooperative nodes which satisfy a probabilistic delay bound are computed. We then derive a sufficient condition that ensures an increase in packet delivery probability. Unlike numerical evaluation of the model, this sufficient condition does not require computation of stationary distribution of the Markov chain. It only involves parameter adjustment at physical, radio link, and application layers, hence substantially reducing the com-putation effort. Based on the developed model, we design a power allocation algorithm, which computes the minimum transmission power under a packet delivery probability constraint. We then use the derived sufficient condition to reduce complexity of the power allocation algorithm.
Web-based education against computer anxiety of greek health care professionals
Authors: Constantinos Koutsojannis, Andrew Andrikopoulos, Helias Patakas, Ioannis Basilakakis, Maria Katsardi
Venue: Proceedings of the 12th WSEAS international conference on Computers (2008)

Although several studies in different countries have explored the extent to which health care professionals use biomedical technology as well as the computer and the internet, few researches are available on this subject in Greece. One hundred health care professionals of the main Hospitals of Western Greece, participated during last four years, to a web-based course, including basic computer skills that designed to assist the faculty in becoming comfortable computer users. The applications addressed included: introduction to MS Windows, electronic mail, word processing, presentation and database applications, library on-line searches of literature databases and introduction to internet browsers. The participants completed a-16 item questionnaire before and after the course. The mean age for the participants were 40.5 years. Overall, 32.6% of the entire sample could use the computer, 67.4% could not. Slightly more than two thirds (75%) of the entire health care professionals had never used the internet, and 25% had. The total improvement of new technology familiarization was statistically significant (usually p<0.0001). Improved efforts such as inclusion of more web-based courses in health care curricular or in life long learning programs additionally with establishment of computer laboratories are required to increase the health care professional's access to computers and internet, conquering computer anxiety.
A new constrained edit distance between quotiented ordered trees
Authors: Aïda Ouangraoua, Pascal Ferraro
Venue: Journal of Discrete Algorithms (2009)

In this paper we propose a dynamic programming algorithm to compare two quotiented ordered trees using a constrained edit distance. An ordered tree is a tree in which the left-to-right order among siblings is significant. A quotiented ordered tree is an ordered tree T with an equivalence relation on vertices and such that, when the equivalence classes are collapsed to super-nodes, the graph so obtained is an ordered tree as well. Based on an algorithm proposed by Zhang and Shasha [K. Zhang, D. Shasha, Simple fast algorithms for the editing distance between trees and related problems, SIAM Journal on Computing 18 (6) (1989) 1245-1262] and introducing new notations, we describe a tree edit distance between quotiented ordered trees preserving equivalence relations on vertices during computation which works in polynomial time. Its application to RNA secondary structures comparison is finally presented.