ppxscal/embedding_network huggingface dataset:
Integrating fuzzy multicriteria analysis and uncertainty evaluation in life cycle assessment
Authors: Enrico Benetto, Christiane Dujet, Patrick Rousseaux
Venue: Environmental Modelling Software (2008)

The interpretation phase of Life Cycle Assessment (LCA) studies is often hampered by the number and the heterogeneity of impact assessment results as well as by the uncertainties arising from data, models and practitioner's choices. While decision-aiding methods have proven to support this key LCA phase, the inclusion of uncertainty evaluations in these methods is still a new topic in the LCA community. The fuzzy multicriteria method NAIADE [Munda G., 1995. Multicriteria Evaluation in a Fuzzy Environment. Heidelberg: Springer-Verlag.] has already been used in several LCA case studies and its framework is well suited for the consideration of uncertainty evaluations as well. This paper proposes a modified version of NAIADE, which conforms to the LCA requirements and to the type of uncertainties to be addressed, with an application example. The discussion of the rankings obtained showed how the integration of uncertainty results could help focusing on critical LCA issues and could be coupled with dominance, contribution and gravity analysis for the interpretation of LCA results, especially when the rankings are not fully consistent. This could support engineers and scientists working in LCA discipline as well as managers and decision-makers faced with decision-making problems based on LCA.
Roundoff errors for polynomial evaluation by a family of formulae
Authors: J. M. Carnicer, T. N. T. Goodman, J. M. Pe&#x00f1;a
Venue: Computing (2008)

A roundoff error analysis of formulae for evaluating polynomials is performed. The considered formulae are linear combinations of basis functions, which can be computed with high relative accuracy. We have taken into account that all steps but the last one can be computed to high relative accuracy. The exactness of the initial data is crucial for obtaining low error bounds. The Lagrange interpolation formula and related formulae are considered and numerical experiments are provided.
A methodology to design information retrieval systems (MDIRS)
Authors: João Ferreira, Alberto Silva, José Delgado
Venue: Proceedings of the 2007 Euro American conference on Telematics and information systems (2007)

MDIRS is methodology to define the actors and the steps to build efficiently information retrieval (IR) System. MDRIS main mission is to analyze, develop and evaluate mechanisms and tools to produce IR systems from a more abstract, high level, efficient and productive way than it is done currently. MDIRS project is influenced by MDA reference model, and is mainly based on three principles: namely, high-level models specification; generative programming techniques; and it is component-based architecture-centric. In this paper we detail the methodology generative programming techniques used to produce IR Systems and the work that will be handled in the near future.
On the first integrals of Kdv equation and the trace formulas of Deift-Trubowitz type
Authors: Mayumi Ohmiya, Yu Yamamoto
Venue: Proceedings of the 12th WSEAS International Conference on Applied Mathematics (2007)

A new type of the first integrals associated with KdV equation is constructed by applying the trace formulas of Deift-Trubowitz type for the 1-dimensional Schrödinger operator with no bound states. The relations between the well-known first integrals with the densities expressed in terms of differential polynomials and the present first integrals are obtained.
On two numerical methods for state-constrained elliptic control problems
Authors: Chr. Meyer, U. Prüfert, F. Tröltzsch
Venue: Optimization Methods Software (2007)

A linear-quadratic elliptic control problem with pointwise box constraints on the state is considered. The state constraints are treated by a Lavrentiev type regularization. It is shown that the Lagrange multipliers associated with the regularized state constraints are functions in L2. Moreover, the convergence of the regularized controls is proven for regularization parameter tending to zero. To solve the problem numerically, an interior point method and a primal-dual active set strategy are implemented and treated in function space.
A framework for the simulation of structural software evolution
Authors: Benjamin Stopford, Steve Counsell
Venue: ACM Transactions on Modeling and Computer Simulation (TOMACS) (2008)

As functionality is added to an aging piece of software, its original design and structure will tend to erode. This can lead to high coupling, low cohesion and other undesirable effects associated with spaghetti architectures. The underlying forces that cause such degradation have been the subject of much research. However, progress in this field is slow, as its complexity makes it difficult to isolate the causal flows leading to these effects. This is further complicated by the difficulty of generating enough empirical data, in sufficient quantity, and attributing such data to specific points in the causal chain. This article describes a framework for simulating the structural evolution of software. A complete simulation model is built by incrementally adding modules to the framework, each of which contributes an individual evolutionary effect. These effects are then combined to form a multifaceted simulation that evolves a fictitious code base in a manner approximating real-world behavior. We describe the underlying principles and structures of our framework from a theoretical and user perspective; a validation of a simple set of evolutionary parameters is then provided and three empirical software studies generated from open-source software (OSS) are used to support claims and generated results. The research illustrates how simulation can be used to investigate a complex and under-researched area of the development cycle. It also shows the value of incorporating certain human traits into a simulation&mdash;factors that, in real-world system development, can significantly influence evolutionary structures.
Cost evaluation on secure routing over powerlines for WMNs
Authors: S. Y. Hui, K. H. Yeung, K. Y. Wong
Venue: Proceedings of the 13th International Conference on Parallel and Distributed Systems - Volume 02 (2007)

In Wireless Mesh Networks (WMNs), wireless nodes exchange routing messages among themselves to build routing tables. Since routing messages are sensitive and critical information, they should be kept confidential and protected. However, the existing WMNs convey the routing messages in an open medium (air) where the messages can be accessed publicly. By abusing the messages, attackers could launch various kinds of attack such as black hole, wormhole, reply, denial of services, and routing table poisoning. In this paper, we present a secure routing architecture for WMNs in which the routing messages are protected by making use of powerline as the routing medium. We also propose three routing protocols for the proposed architecture. The implementation costs of these protocols are evaluated under different scenarios.
A scalable LDPC decoder ASIC architecture with bit-serial message exchange
Authors: Tyler Brandon, Robert Hang, Gary Block, Vincent C. Gaudet, Bruce Cockburn, Sheryl Howard, Christian Giasson, Keith Boyle, Paul Goud, Siavash Sheikh Zeinoddin, Anthony Rapley, Stephen Bates, Duncan Elliott, Christian Schlegel
Venue: Integration, the VLSI Journal (2008)

We present a scalable bit-serial architecture for ASIC realizations of low-density parity check (LDPC) decoders. Supporting the architecture's potential, we describe a decoder implementation for a (256,128) regular-(3,6) LDPC code that has a decoded information throughput of 250Mbps, a core area of 6.96mm^2 in 180-nm 6-metal CMOS, and an energy efficiency of 7.56nJ per uncoded bit at low signal-to-noise ratios. The decoder is fully block-parallel, with all bits of each 256-bit codeword being processed by 256 variable nodes and 128 parity check nodes that together form an 8-stage iteration pipeline. Extrinsic messages are exchanged bit-serially between the variable and parity check nodes to significantly reduce the interleaver wiring. Parity check node processing is also bit-serial. The silicon implementation performs 32 iterations of the min-sum decoding algorithm on two staggered codewords in the same pipeline. The results of a supplementary layout study show that the reduced wiring congestion makes the decoder readily scaleable up to the longer kilobit-size LDPC codewords that appear in important emerging communication standards.
An iterative semi-implicit scheme with robust damping
Authors: N. F. Loureiro, G. W. Hammett
Venue: Journal of Computational Physics (2008)

An efficient, iterative semi-implicit (SI) numerical method for the time integration of stiff wave systems is presented. Physics-based assumptions are used to derive a convergent iterative formulation of the SI scheme which enables the monitoring and control of the error introduced by the SI operator. This iteration essentially turns a semi-implicit method into a fully implicit method. Accuracy, rather than stability, determines the timestep. The scheme is second order accurate and shown to be equivalent to a simple preconditioning method. We show how the diffusion operators can be handled so as to yield the property of robust damping, i.e. dissipating the solution at all values of the parameter D@Dt, where D is a diffusion operator and @Dt the timestep. The overall scheme remains second order accurate even if the advection and diffusion operators do not commute. In the limit of no physical dissipation, and for a linear test wave problem, the method is shown to be symplectic. The method is tested on the problem of Kinetic Alfven wave mediated magnetic reconnection. A Fourier (pseudo-spectral) representation is used. A two-field gyrofluid model is used and an efficacious k-space SI operator for this problem is demonstrated. CPU speed-up factors over a CFL-limited explicit algorithm ranging from ~20 to several hundreds are obtained, while accurately capturing the results of an explicit integration. Possible extension of these results to a real-space (grid) discretization is discussed.
Polynomial threshold functions, AC functions and spectrum norms
Authors: J. Bruck
Venue: Proceedings of the 31st Annual Symposium on Foundations of Computer Science (1990)

The class of polynomial-threshold functions is studied using harmonic analysis, and the results are used to derive lower bounds related to AC/sup 0/ functions. A Boolean function is polynomial threshold if it can be represented as a sign function of a sparse polynomial (one that consists of a polynomial number of terms). The main result is that polynomial-threshold functions can be characterized by means of their spectral representation. In particular, it is proved that a Boolean function whose L/sub 1/ spectral norm is bounded by a polynomial in n is a polynomial-threshold function, and that a Boolean function whose L/sub infinity //sup -1/ spectral norm is not bounded by a polynomial in n is not a polynomial-threshold function. Some results for AC/sup 0/ functions are derived.
An Adaptive Caching Strategy for m-Learning Based on SCORM Sequencing and Navigation
Authors: Hsuan Pu Chang, Timothy K. Shih, Qing Li, Chun-Chia Wang, Te-Hua Wang, Louis R. Chao
Venue: World Wide Web (2008)

One of the main problems encountered in the usage of mobile devices as a learning platform is the presence of an impermanent network environment due to insufficient coverage or link failure in wireless communication. On the other hand, a persistent connection is usually offered by cellular phones using a telecommunication protocol, but with a relatively weak computing power and very limited network bandwidth which makes m-learning a time-consuming process. Moreover, learning contents are currently composed of various multimedia resources that induce long latency to display on handheld devices such as smartphones with GPRS. Recently, a lot of m-learning systems and contents have conformed to the Sharable Content Object Reference Model (SCORM) since it was introduced by ADL in the late 90s. The Sequencing and Navigation (S N) specification is an important part of SCORM. S N is defined to prescribe the intended student learning sequence by instructors. In this paper, we propose an adaptive course caching strategy based on the S N specification in an m-learning environment. The system automatically switches to the corresponding course caching strategies, namely, the virtual memory management (VMM) mode and caching on disk (COD) mode, according to the current networking capability. The proposed mechanism is implemented on an m-learning system--Pocket SCORM--which received the 2005 Brandon Hall Excellence in Learning Award in the USA. Our simulation and experiments demonstrate that the proposed course caching strategy ultimately reduces the latency during the learning process and decreases the requests for Internet reconnection.
Preference networks: probabilistic models for recommendation systems
Authors: Tran The Truyen, Dinh Q. Phung, Svetha Venkatesh
Venue: Proceedings of the sixth Australasian conference on Data mining and analytics - Volume 70 (2007)

Recommender systems are important to help users select relevant and personalised information over massive amounts of data available. We propose an unified framework called Preference Network (PN) that jointly models various types of domain knowledge for the task of recommendation. The PN is a probabilistic model that systematically combines both content-based filtering and collaborative filtering into a single conditional Markov random field. Once estimated, it serves as a probabilistic database that supports various useful queries such as rating prediction and top-N recommendation. To handle the challenging problem of learning large networks of users and items, we employ a simple but effective pseudo-likelihood with regularisation. Experiments on the movie rating data demonstrate the merits of the PN.
Delpsc: a delaunay mesher for piecewise smooth complexes
Authors: Tamal K. Dey, Joshua A. Levine
Venue: Proceedings of the twenty-fourth annual symposium on Computational geometry (2008)

This video presents the working of a new algorithm/software called DelPSC that meshes piecewise smooth complexes in three dimensions with Delaunay simplices. Piecewise smooth complexes admit a large class of geometric domains including polyhedra, smooth and piecewise smooth surfaces with or without boundary, and non-manifolds. The algorithm and its proof of correctness are described in the paper [7].
A Fault Inference Mechanism in Sensor Networks Using Markov Chain
Authors: Elhadi Shakshuki, Xinyu Xing
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications (2008)

The reliability of communication and sensor devices has been recognized as one of the crucial issues in Wireless Sensor Networks (WSNs). In distributed environments, micro-sensors are subject to high-frequency faults. To provide high stability and availability of large scale sensor networks, we propose a fault inference mechanism based on reverse multicast tree to evaluate sensor nodes’ fault probabilities. This mechanism is formulated as maximization-likelihood estimation problem. Due to the characteristics (energy awareness, constraint bandwidth and so on) of wireless sensor networks; it is infeasible for each sensor to announce its working state to a centralized node. Therefore, maximum likelihood estimates of fault parameters depend on unobserved latent variables. Hence, our proposed inference mechanism is abstracted as Nondeterministic Finite Automata (NFA). It adopts iterative computation under Markov Chain to infer the fault probabilities of nodes in reverse multicast tree. Through our theoretical analysis and simulation experiments, we were able to achieve an accuracy of fault inference mechanism that satisfies the necessity of fault detection.
Modified Cholesky algorithms: a catalog with new approaches
Authors: Haw-ren Fang, Dianne P. O&#x2019;Leary
Venue: Mathematical Programming: Series A and B (2008)

Given an n &#x00d7;&#x00a0; n symmetric possibly indefinite matrix A, a modified Cholesky algorithm computes a factorization of the positive definite matrix A +&#x00a0; E, where E is a correction matrix. Since the factorization is often used to compute a Newton-like downhill search direction for an optimization problem, the goals are to compute the modification without much additional cost and to keep A +&#x00a0; E well-conditioned and close to A. Gill, Murray and Wright introduced a stable algorithm, with a bound of ||E||2 =&#x00a0; O(n 2). An algorithm of Schnabel and Eskow further guarantees ||E||2 =&#x00a0; O(n). We present variants that also ensure ||E||2 =&#x00a0; O(n). Mor&#x00e9; and Sorensen and Cheng and Higham used the block LBL T factorization with blocks of order 1 or 2. Algorithms in this class have a worst-case cost O(n 3) higher than the standard Cholesky factorization. We present a new approach using a sandwiched LTL T -LBL T factorization, with T tridiagonal, that guarantees a modification cost of at most O(n 2).
Motions of infinite mass-spring systems
Authors: Khiem V. Ngo
Venue: Proceedings of the 7th WSEAS International Conference on Applied Mathematics (2005)

In the study of physical, mechanical, and electrical systems one often encounters differential-difference equations and recurrence relations. The sources from which these equations arise may be quite different but their mathematical forms are very similar. For example, there is an analogy between mass-spring systems and electrical systems whereby point masses correspond to inductances and springs correspond to capacitances [1]. Another area where differential-difference equations occur is in the numerical solution of the wave equations if the spatial variable is discretized [2]. It's important to understand how these systems behave as time evolves and how changes in the parameters of the model influence this behavior. In this paper, we study systems consisting of point masses joined together by springs. In particular, we present some of the mathematical methods involved and how they are used to solve these practical problems. By obtaining the solution for these simple mass-spring systems, we indirectly obtain solutions for many similar applied problems in mechanics, physics, and engineering.
Complecto mutatio: teaching software design best practices using multi-platform development
Authors: Randy W. Connolly
Venue: ACM SIGCSE Bulletin (2008)

Students can best understand the benefits of software design principles when they have to work on a project in which requirements change repeatedly in some substantial way over the course of a semester. This poster describes two different semester-long projects in which substantial change was enforced upon the students by making them develop a system that had to work on three different user interface platforms (text-based console, desktop Windows, and a mobile Pocket PC). By making the students plan and adapt for this change the students were better able to truly appreciate the benefits of good design and were willing to take the extra effort to implement a design that reflects the principles taught in most object-oriented design courses. One of the key principles engaged by this approach was the importance of a layered architecture to software projects driven by change.
Exploiting Environmental Properties for Wireless Localization and Location Aware Applications
Authors: Shu Chen, Yingying Chen, Wade Trappe
Venue: Proceedings of the 2008 Sixth Annual IEEE International Conference on Pervasive Computing and Communications (2008)

Wireless sensor networks monitor phenomena that vary over the spatial region the sensor network covers. The sensor readings may also be dual-used for additional purposes. In this paper we propose to use the inherent spatial variability in physical phenomena to support localization and position verification. We first present the problem of localization using general spatial information fields, and then propose a theory for exploiting this spatial variability for localization. Our Spatio-Correlation Weighting Mechanism (SCWM) uses spatial relationships of measured physical phenomena to determine an appropriate subset of environmental parameters for better locationaccuracy. We next present the Flex-EP algorithm, which supports our theoretical model for performing localization. Finally, we provide an experimental evaluation of our approach by using a collection of physical phenomena measured across one hundred locations inside a building. Our results provide strong evidence of the viability of using general sensor readings for location applications.
Multi-classification by categorical features via clustering
Authors: Yevgeny Seldin, Naftali Tishby
Venue: Proceedings of the 25th international conference on Machine learning (2008)

We derive a generalization bound for multi-classification schemes based on grid clustering in categorical parameter product spaces. Grid clustering partitions the parameter space in the form of a Cartesian product of partitions for each of the parameters. The derived bound provides a means to evaluate clustering solutions in terms of the generalization power of a built-on classifier. For classification based on a single feature the bound serves to find a globally optimal classification rule. Comparison of the generalization power of individual features can then be used for feature ranking. Our experiments show that in this role the bound is much more precise than mutual information or normalized correlation indices.
Extending Mixed Serialisation Graphs to Replicated Environments
Authors: Josep M. Bernabé-Gisbert, Francesc D. Muñoz-Escoí
Venue: Proceedings of the 2008 Third International Conference on Availability, Reliability and Security (2008)

Replication has been told to be a solution to provide scalability and high availability in databases. Unfortunately, the cost of ensuring isolated and consistent executions is sometimes too high. Weakest isolation models have proved to be a way to reduce this cost but they can violate some applications transactions isolation needs. In stand-alone systems, models supporting different isolation restrictions for concurrent transaction are used to avoid this dilemma. With this kind of protocols, applications can specify every transaction isolation requirements. However, how to extend these models to replicated systems is still an issue. In this paper we extend Adya's model based on serialization graphs as a first step to construct replication protocols with such a feature.
K 4-free subgraphs of random graphs revisited
Authors: S. Gerke, H. J. Pr&#x00f6;mel, T. Schickinger, A. Steger, A. Taraz
Venue: Combinatorica (2007)

In Combinatorica 17(2), 1997, Kohayakawa, &#x0141;uczak and R&#x00f6;dl state a conjecture which has several implications for random graphs. If the conjecture is true, then, for example, an application of a version of Szemer&#x00e9;di&#x2019;s regularity lemma for sparse graphs yields an estimation of the maximal number of edges in an H-free subgraph of a random graph G n, p . In fact, the conjecture may be seen as a probabilistic embedding lemma for partitions guaranteed by a version of Szemer&#x00e9;di&#x2019;s regularity lemma for sparse graphs. In this paper we verify the conjecture for H = K 4, thereby providing a conceptually simple proof for the main result in the paper cited above.