ppxscal/embedding_network huggingface dataset:
About solutions of renewal equations and determinations of failure moments of a system as equilibrium points
Authors: Ilie Mitran
Venue: WSEAS Transactions on Mathematics (2009)

The results presented in this paper lead to solving main problems of the reliability theory: specifying the failure moments of a failure and determining the solutions of renewal equations. We analyze the following situations: 1. the system structure is not taken into consideration; 2. the system structure is known. In the first case we presume that the adopted efficiency function is the average operation time and, by using specific methods of the theory of games, we can prove that there is no equilibrium type solution, so the failure moment of the system cannot be precisely determined. By solving some specific problems, type maximum or minimax, we can only get the interval where the failure point of the system is found. The optimal problem type maximum is solved by specific methods from the theory of games while the optimal problem type minimax is solved by using the maximum principle of Pontriaghin. In the second case we start from the graph structure associated to a system with renewal operations and we build immediately the equation system with finite differences and the system of differential equations associated to this graph. Applying the Laplace transformation it is determined the system availabilities and unavailabilities caused by its subsystems. The failure moments of the system are determined as equilibrium points but the difficulties in calculations lead to obtaining only an approximate solution. Knowing the failure moments of the analyzed system lead to the reconsideration of the renewal policies of the system. Practically, there are determined the approximate solutions of the renewal equations and their separation curve. Having these elements we can completely analyze the renewal process; this analysis being based both on the failure moments of the system and on the renewal costs of the analyzed system.
Exact Minkowksi Sums of Polyhedra and&#x00a0;Exact and&#x00a0;Efficient Decomposition of Polyhedra into&#x00a0;Convex&#x00a0;Pieces
Authors: Peter Hachenberger
Venue: Algorithmica (2009)

We present the first exact and robust implementation of the 3D Minkowski sum of two non-convex polyhedra. Our implementation decomposes the two polyhedra into convex pieces, performs pairwise Minkowski sums on the convex pieces, and constructs their union. We achieve exactness and the handling of all degeneracies by building upon 3D Nef polyhedra as provided by Cgal. The implementation also supports open and closed polyhedra. This allows the handling of degenerate scenarios like the tight passage problem in robot motion planning. The bottleneck of our approach is the union step. We address efficiency by optimizing this step by two means: we implement an efficient decomposition that yields a small number of convex pieces, and develop, test and optimize multiple strategies for uniting the partial sums by consecutive binary union operations. The decomposition that we implemented as part of the Minkowski sum is interesting in its own right. It is the first robust implementation of a decomposition of polyhedra into convex pieces that yields at most O(r 2) pieces, where r is the number of edges whose adjacent facets comprise an angle of more than 180 degrees with respect to the interior of the polyhedron.
Assessment Of Group And Individual Learning Through Visualization (Agileviz) In Education
Authors: Eric R. Hamilton
Venue: Proceeding of the 2007 conference on Supporting Learning Flow through Integrative Technologies (2007)

The purpose of this paper is to stimulate interest and conversation in an area of significant potential for assessment systems in future education environments. This paper makes two arguments en route to the proposition that it may be possible, in a relatively short time frame, to effect a quantum jump in the utility of existing learner assessments via the use of integrative computer graphics.
An auto-scoring mechanism for evaluating problem-solving ability in a web-based learning environment
Authors: Chuang-Kai Chiou, Gwo-Jen Hwang, Judy C. R. Tseng
Venue: Computers Education (2009)

The rapid development of computer and network technologies has attracted researchers to investigate strategies for and the effects of applying information technologies in learning activities; simultaneously, learning environments have been developed to record the learning portfolios of students seeking web information for problem-solving. Although previous research has demonstrated the benefits of applying information technologies to learning activities, the difficulties in doing so have also been revealed. One of the major difficulties is the lack of a mechanism to assist teachers in evaluating the problem-solving ability of the students, such that constructive suggestions can be given to the students, and tutoring strategies can be improved accordingly. To cope with this problem, in this paper, an auto-scoring mechanism is developed to analyze the various information searching abilities of individual students. Indicators of information searching ability (ISA) are proposed based on the famous Big6 model and are adopted in our auto-scoring mechanism. Moreover, two experiments have been conducted to demonstrate the effectiveness of this innovative approach. The experimental results show high correlation between the scores of the auto-scoring mechanism and the manual scoring. Moreover, the feedbacks from 158 teachers also show that the innovative approach is highly accepted by the teachers.
Understanding Sustained Participation in Open Source Software Projects
Authors: Yulin Fang, Derrick Neufeld
Venue: Journal of Management Information Systems (2009)

Prior research into open source software (OSS) developer participation has emphasized individuals' motivations for joining these volunteer communities, but it has failed to explain why people stay or leave in the long run. Building upon Lave and Wenger's theory of legitimate peripheral participation (LPP), this paper offers a longitudinal investigation of one OSS community in which sustained participation is hypothesized to be associated with the coevolution of two major elements of LPP theory: "situated learning" (the process of acting knowledgeably and purposefully in the world) and "identity construction" (the process of being identified within the community). To test this hypothesis, data were collected from multiple sources, including online public project documents, electronic mail messages, tracker messages, and log files. Results from qualitative analyses revealed that initial conditions to participate did not effectively predict long-term participation, but that situated learning and identity construction behaviors were positively linked to sustained participation. Furthermore, this study reveals that sustained participants distinguished themselves by consistently engaging in situated learning that both made conceptual (advising others) and practical contributions (improving the code). Implications and future research are discussed.
MoKi: The Enterprise Modelling Wiki
Authors: Chiara Ghidini, Barbara Kump, Stefanie Lindstaedt, Nahid Mahbub, Viktoria Pammer, Marco Rospocher, Luciano Serafini
Venue: Proceedings of the 6th European Semantic Web Conference on The Semantic Web: Research and Applications (2009)

Enterprise modelling focuses on the construction of a structured description, the so-called enterprise model, which represents aspects relevant to the activity of an enterprise. Although it has become clearer recently that enterprise modelling is a collaborative activity, involving a large number of people, most of the enterprise modelling tools still only support very limited degrees of collaboration. Within this contribution we describe a tool for enterprise modelling, called MoKi (MOdelling wiKI), which supports agile collaboration between all different actors involved in the enterprise modelling activities. MoKi is based on a Semantic Wiki and enables actors with different expertise to develop an enterprise model not only using structural (formal) descriptions but also adopting more informal and semi-formal descriptions of knowledge.
Letters: Feature extraction using fuzzy inverse FDA
Authors: Wankou Yang, Jianguo Wang, Mingwu Ren, Lei Zhang, Jingyu Yang
Venue: Neurocomputing (2009)

This paper proposes a new method of feature extraction and recognition, namely, the fuzzy inverse Fisher discriminant analysis (FIFDA) based on the inverse Fisher discriminant criterion and fuzzy set theory. In the proposed method, a membership degree matrix is calculated using FKNN, then the membership degree is incorporated into the definition of the between-class scatter matrix and within-class scatter matrix to get the fuzzy between-class scatter matrix and fuzzy within-class scatter matrix. Experimental results on the ORL, FERET face databases and pulse signal database show that the new method outperforms Fisherface, fuzzy Fisherface and inverse Fisher discriminant analysis.
On-demand multipath protocol with adaptive routing method by back propagation neural networks
Authors: Fang Jing, R. S. Bhuvaneswaran, Yoshiaki Katayama, Naohisa Takahashi
Venue: International Journal of Communication Networks and Distributed Systems (2009)

Two representative multipath routing protocol strategies have been utilised currently, one is described as primary routing protocol and the other is load-balancing protocol. In the former routing protocol, the source selects the pre-computed shortest or fastest route as the primary one for the following data transmission. On the other hand, the latter routing protocol utilises multiple routes in rotation to equalise transmission load in the network. However, these solutions suffer during high mobility since they are lacking in global perspective for the following data transmission, resulting in low packet delivery ratio and prolonged delay time. Hence, to find the optimum routing protocol strategy, we present an adaptive multipath routing protocol by means of applying golden section search and back propagation neural networks. We evaluated our protocol using Omnet simulator. Simulation results show that the proposed solution has a good real-time performance than those of other protocols.
Using noise inconsistencies for blind image forensics
Authors: Babak Mahdian, Stanislav Saic
Venue: Image and Vision Computing (2009)

A commonly used tool to conceal the traces of tampering is the addition of locally random noise to the altered image regions. The noise degradation is the main cause of failure of many active or passive image forgery detection methods. Typically, the amount of noise is uniform across the entire authentic image. Adding locally random noise may cause inconsistencies in the image's noise. Therefore, the detection of various noise levels in an image may signify tampering. In this paper, we propose a novel method capable of dividing an investigated image into various partitions with homogenous noise levels. In other words, we introduce a segmentation method detecting changes in noise level. We assume the additive white Gaussian noise. Several examples are shown to demonstrate the proposed method's output. An extensive quantitative measure of the efficiency of the noise estimation part as a function of different noise standard deviations, region sizes and various JPEG compression qualities is proposed as well.
Personalised Electromechanical Model of the Heart for the Prediction of the Acute Effects of Cardiac Resynchronisation Therapy
Authors: Maxime Sermesant, Florence Billet, Radomir Chabiniok, Tommaso Mansi, Phani Chinchapatnam, Philippe Moireau, Jean-Marc Peyrat, Kawal Rhode, Matt Ginks, Pier Lambiase, Simon Arridge, Hervé Delingette, Michel Sorine, C. Aldo Rinaldi, Dominique Chapelle, Reza Razavi, Nicholas Ayache
Venue: Proceedings of the 5th International Conference on Functional Imaging and Modeling of the Heart (2009)

Cardiac resynchronisation therapy (CRT) has been shown to be an effective adjunctive treatment for patients with dyssynchronous ventricular contraction and symptoms of the heart failure. However, clinical trials have also demonstrated that up to 30% of patients may be classified as non-responders. In this article, we present how the personalisation of an electromechanical model of the myocardium could help the therapy planning for CRT. We describe the four main components of our myocardial model, namely the anatomy, the electrophysiology, the kinematics and the mechanics. For each of these components we combine prior knowledge and observable parameters in order to personalise these models to patient data. Then the acute effects of a pacemaker on the cardiac function are predicted with the in silico model on a clinical case. This is a proof of concept of the potential of virtual physiological models to better select and plan the therapy.
Progressive assignment in CS1
Authors: Mirela Djordjević
Venue: ACM SIGCSE Bulletin (2009)

This paper proposes a simple graphics programming project, Java Target project that follows the Spiral Model of teaching three different components of the introductory programming course: fundamentals, object-oriented, and event-driven programming. Especially important in this project is the progressive nature that introduces one concept and reviews others. The project consists of following progressive tasks: draw a circle (target); user defines radius, and center of a circle; report number of shots; randomize shots; select color, select shape, resize target; define user class Circle (Target); define number of circles in target; keep scores and find the best score.
Boolean applications in aircraft electric power systems reliability analysis
Authors: Nicolae Jula, Costin Cepisca, Mircea Covrig, Ciprin Racuciu, Tudor Ursu
Venue: Proceedings of the 2nd conference on European computing conference (2008)

The paper presents a concrete case of an actual aircraft electric power system analysis. Using the Boolean logical structures we define a conceptual fault tree. The fault tree will express all the combination of factors that can lead to system failure in the onboard electric system. The further on analysis rely on AND - OR logic elements, and the goal is to improve the fault-tolerance behavior of the system. The examples and numeric figures are for a c.c. electric power system of an operational aircraft.
An Introduction to the Quantitative, Rational and Scientific Process of Software Development (Part 2)
Authors: Zenya Koonoa, Hui Chenb, Hassan Abolhassanic
Venue: Proceeding of the 2007 conference on New Trends in Software Methodologies, Tools and Techniques: Proceedings of the sixth SoMeT_07 (2007)

“Product” and “process” are two mutually orthogonal and important aspects of software. As Part 1 discusses “product”, Part 2 discusses “process”. “Process” is independent of “product” and is used commonly by various “producers”. This paper first explains the structure of “process” and then introduces important technique by “divide and conquer”. Various important management issues are discussed.
Probabilistically reliable on-demand multicast in wireless mesh networks
Authors: Xin Zhao, Chun Tung Chou, Jun Guo, Sanjay Jha, Archan Misra
Venue: Proceedings of the 2008 International Symposium on a World of Wireless, Mobile and Multimedia Networks (2008)

This paper studies probabilistically reliable multicast in wireless mesh networks (WMNs), utilizing MAC layer re-transmission and wireless broadcast advantage to improve both the multicast throughput and the delivery rate. We first present a new multicast routing metric which we call the expected multicast transmissions (EMT). EMT captures the effect of link packet delivery ratio, MAC layer retransmission and wireless broadcast advantage at the same time. The EMT of a MAC layer multicast transmission is the expected number of data transmissions (including retransmissions) required for a packet to reach all the recipients. The EMT of a multicast tree is the sum over the EMT of each forwarding node. Then, we propose a probabilistically reliable on-demand (PROD) multicast protocol with the objective of minimizing the EMT of the multicast tree. Simulation results show that, in comparison with existing approaches, PROD reduces the end-to-end packet loss ratio by up to 30% and improves the multicast throughput by up to 25%. In addition, it reduces the number of transmissions per packet by up to 40% and thus significantly reduces the network overhead of the multicast session.
A haptic device DELTA-4: Kinematics and its analysis
Authors: Jumpei Arata, Hiroyuki Kondo, Masamichi Sakaguchi, Hideo Fujimoto
Venue: Proceedings of the World Haptics 2009 - Third Joint EuroHaptics conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (2009)

In this paper, a new parallel link mechanism “DELTA-4” is developed as a new haptic device within a high quality force display capability and operability. DELTA-4 realizes 3 DOF of translational motions by a new redundant parallel link mechanism. The name of the mechanism DELTA-4 is derived from a conventional parallel link mechanism “DELTA”, because there are several common points on motion constraints of end-effector. However, these benefits can be obtained by DELTA-4: wider working area, smaller footprint, better mechanical access of end-effector from operators.
Using Agility in Ontology Construction
Authors: Amir Azim Sharifloo, Mehrnoush Shamsfard
Venue: Proceeding of the 2008 conference on Formal Ontologies Meet Industry (2008)

Ontology development method is a method that shows how to construct an ontology. Many approaches have been reported for developing ontologies. Almost all of them are derived from traditional software development methods and consequently, have inherited their weaknesses. In the last decade, agile methods have appeared in software development area. These methods attempt to solve some problems of traditional methods. In this paper, one famous agile method that is known as Extreme Programming (XP) is adapted for ontology construction. Also, we report the ontology constructed using this method.
On conditions for the liveness of weakly persistent nets
Authors: GuanJun Liu, ChangJun Jiang
Venue: Information Processing Letters (2009)

This paper first proves that each minimal siphon in a weakly persistent net is a trap if its pre-set is nonempty. Therefore, each minimal siphon contains a marked trap if a weakly persistent net is live for an initial marking. Next, it is proved that the condition, each minimal siphon contains a marked trap, is both necessary and sufficient for the liveness of weakly persistent nets if these nets additionally satisfy the asymmetric choice property or the intrinsic fairness.
Channel Segmentation using Confidence and Curvature-Guided Level Sets on Noisy Seismic Images
Authors: Benjamin J. Kadlec
Venue: Proceedings of the 2008 IEEE Workshop on Applications of Computer Vision (2008)

This paper presents a new method for segmenting channel features from commonly noisy 3D seismic images. Anisotropic diffusion using Gaussian-smoothed first order structure tensors is conducted along the strata of seismic images in a way that filters across discontinuous regions from noise or faulting, while preserving channel edges. The eigenstructure of the second order structure tensor is used to generate an estimation of orientation and channel curvature. Gaussian smoothing of second order tensor orientations accounts for noisy vectors from imprecise finite difference calculations and generates a stable tensor across the image. Analysis of the confidence and direction of second order eigenvectors is used to enhance depositional curvature in channel features by generating a confidence and curvature attribute. The tensor-derived attribute forms the terms of a PDE, which is iteratively updated as an implicit surface using the level set process. This technique is tested on two 3D seismic images with results that demonstrate the effectiveness of the approach. 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
Bifurcation-analysis technique for nonlinear, parametric effects in 3D magnetic nanodevices at microwaves and photonics
Authors: G. S. Makeeva, O. A. Golovanov
Venue: Proceedings of the 2nd conference on European computing conference (2008)

The developed technique involves numerical determination of bifurcation points of the nonlinear Maxwell equations complemented by the Landau-Lifshitz equation with the exchange term taking into account the electrodynamical boundary conditions for 3D magnetic nanodevices. A special computational algorithm has been developed for determination of bifurcation points of the nonlinear Maxwell operator including the Landau-Lifshitz equation. The bifurcation points are found from the eigenvalues of the characteristic equation of the linearized Maxwell operator via the use of necessary and sufficient conditions for the existence of a bifurcation point. The original computational algorithm is improved by combining it with a qualitative method of analysis, based on Lyapunov stability theory. The instabilities of parametric excitation process of magnetostatic dipole-dipole waves (MSW) and dipole-exchange spin waves (SW) in periodic bandgap structures of nano-sized magnetic particles is simulated using bifurcation-analysis technique.
Bregman-EM-TV Methods with Application to Optical Nanoscopy
Authors: Christoph Brune, Alex Sawatzky, Martin Burger
Venue: Proceedings of the Second International Conference on Scale Space and Variational Methods in Computer Vision (2009)

Measurements in nanoscopic imaging suffer from blurring effects concerning different point spread functions (PSF). Some apparatus even have PSFs that are locally dependent on phase shifts. Additionally, raw data are affected by Poisson noise resulting from laser sampling and "photon counts" in fluorescence microscopy. In these applications standard reconstruction methods (EM, filtered backprojection) deliver unsatisfactory and noisy results. Starting from a statistical modeling in terms of a MAP likelihood estimation we combine the iterative EM algorithm with TV regularization techniques to make an efficient use of a-priori information. Typically, TV-based methods deliver reconstructed cartoon-images suffering from contrast reduction. We propose an extension to EM-TV, based on Bregman iterations and inverse scale space methods, in order to obtain improved imaging results by simultaneous contrast enhancement. We illustrate our techniques by synthetic and experimental biological data.