Short-term non-uniform access in IEEE 802.11-compliant WLANs: A study on its impact on the saturation performance Along with the success of IEEE 802.11-compliant WLANs, the distributed coordinated function (DCF) specified as the contention-based medium access mechanism in IEEE 802.11 has been widely used to support applications in new regimes. A thorough understanding of the characteristics of IEEE 802.11 DCF is therefore a research focus. DCF assumes the binary exponential backoff algorithm (BEBA) [D. Bertsekas, R. Gallager, Data Networks, Prentice Hall, 1992]. Several existing models that characterize BEBA as a p-persistent scheme have ignored several subtle protocol details. This has practically constrained the models from being applied in a broader range of configurations, e.g., small contention window, and from being further extended, e.g., 802.11e EDCA. In this paper, we develop an analytical model that captures the subtlety, and faithfully describes the channel activities as governed by DCF. Based on the devised model, we perform a rigorous analysis on the saturation throughput performance in a single-hop WLAN. We show that the stochastic property of the backoff time, r, may substantially impact the system performance. For example, setting the range of r to [1,CW] instead of [0,CW?1], can degrade the system throughput considerably. We also identify, by clearly defining and thus being able to differentiate the two terms, attempt probability and transmission probability, an erroneous extension made to Bianchis model [G. Bianchi, Performance analysis of the IEEE 802.11 distributed coordination function, IEEE JSAC, 18(3) (2000) 535547]. All the findings are corroborated by ns-2 simulation.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O


Self-calibration and visual SLAM with a multi-camera system on a micro aerial vehicle The use of a multi-camera system enables a robot to obtain a surround view, and thus, maximize its perceptual awareness of its environment. If vision-based simultaneous localization and mapping (vSLAM) is expected to provide reliable pose estimates for a micro aerial vehicle (MAV) with a multi-camera system, an accurate calibration of the multi-camera system is a necessary prerequisite. We propose a novel vSLAM-based self-calibration method for a multi-camera system that includes at least one calibrated stereo camera, and an arbitrary number of monocular cameras. We assume overlapping fields of view to only exist within stereo cameras. Our self-calibration estimates the inter-camera transforms with metric scale; metric scale is inferred from calibrated stereo. On our MAV, we set up each camera pair in a stereo configuration which facilitates the estimation of the MAVs pose with metric scale. Once the MAV is calibrated, the MAV is able to estimate its global pose via a multi-camera vSLAM implementation based on the generalized camera model. We propose a novel minimal and linear 3-point algorithm that uses relative rotation angle measurements from a 3-axis gyroscope to recover the relative motion of the MAV with metric scale and from 2D-2D feature correspondences. This relative motion estimation does not involve scene point triangulation. Our constant-time vSLAM implementation with loop closures runs on-board the MAV in real-time. To the best of our knowledge, no published work has demonstrated real-time on-board vSLAM with loop closures. We show experimental results from simulation experiments, and real-world experiments in both indoor and outdoor environments.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

micro aerial vehicles
multi-camera systems
self-calibration


An efficient minutiae based geometric hashing for fingerprint database ? This paper proposes an efficient indexing technique for fingerprint database using minutiae based geometric hashing. This technique consists of two stages, known as indexing and searching. For an accurate match at the time of searching, it has proposed a fixed length feature vector built from each minutia, known as Minutia Binary Pattern. Unlike any existing geometric based indexing technique, the proposed technique inserts each minutia along with the feature vector exactly once into a hash table. As a result, it reduces both computational and memory costs. Since minutiae of all fingerprint images in the database are found to be well distributed into the hash table, no rehashing is required. Experiments over FVC 2004 datasets prove the superiority of the proposed indexing technique against well known geometric based indexing techniques.

O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O B O

fingerprints
identification
geometric based hashing


Complex RFID event processing Advances of sensor and radio frequency identification (RFID) technology provide significant new power for humans to sense, understand and manage the world. RFID provides fast data collection with precise identification of objects with unique IDs without line of sight, thus it can be used for identifying, locating, tracking and monitoring physical objects. Despite these benefits, RFID poses many challenges for data processing and management: (i) RFID observations have implicit meanings, which have to be transformed and aggregated into semantic data represented in their data models; and (ii) RFID data are temporal, streaming, and in high volume, and have to be processed on the fly. Thus, a general RFID data processing framework is needed to automate the transformation of physical RFID observations into the virtual counterparts in the virtual world linked to business applications. In this paper, we take an event-oriented approach to process RFID data, by devising RFID application logic into complex events. We then formalize the specification and semantics of RFID events and rules. We discover that RFID events are highly temporal constrained, and include non-spontaneous events, and develop an RFID event detection engine that can effectively process complex RFID events. The declarative event-based approach greatly simplifies the work of RFID data processing, and can significantly reduce the cost of RFID data integration.

O B O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O B O O O O O O O O O O O O O B O O O O O O B O O O B O O O O O O O O B O O O O O O O O B O O O O O O O O O O B O O O O O O O O O B O O


A dynamic large deformation finite element method based on mesh regeneration In this paper, a large deformation finite element (LDFE) approach termed remeshing and interpolation technique with small strain (RITSS) is extended from static to dynamic soil-structure interaction applications. In addition, a technique termed element addition is developed to improve the computational efficiency of both static and dynamic LDFE analyses that involve moving boundaries. The RITSS approach is based on frequent mesh generation to avoid element distortion. In dynamic RITSS, the field variables mapped from the old to the new mesh involve not only the stresses and material properties, but also the nodal velocities and accelerations. Using the element addition technique, new soil elements are attached to the domain boundaries periodically when the soil near the boundaries becomes affected by large displacements of the structure. The procedures of this Abaqus-based dynamic LDFE analysis and element addition technique are detailed, and the robustness of the techniques is validated and assessed through three example analyses: penetration of a flat footing into a half-space and movement of rigid and deformable landslides down slopes.

O O B I B I I O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O B O O O O O O O O O B O O

large deformation
finite element method
penetration
landslides
footing


Computer monitoring: benefits and pitfalls facing management The Information Age has enabled businesses to improve their efficiency through the use of advanced technology. The increase in the use of computers in the workplace has led to the ease of electronic monitoring of employees. Many feel that monitoring is important for the survival of their business. However, some employees regard this action as negatively impacting their work habits and privacy. This article examines the benefits and pitfalls of computer monitoring and recommends specific steps that need to be taken to monitor employees safely and ethically.

B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O

employees privacy
ethical issues
privacy policy
employees rights
corporate security


toward measuring network security using attack graphs In measuring the overall security of a network, a crucial issue is to correctly compose the measure of individual components. Incorrect compositions may lead to misleading results. For example, a network with less vulnerabilities or a more diversified configuration is not necessarily more secure. To obtain correct compositions of individual measures, we need to first understand the interplay between network components. For example, how vulnerabilities can be combined by attackers in advancing an intrusion. Such an understanding becomes possible with recent advances in modeling network security using attack graphs . Based on our experiences with attack graph analysis, we propose an integrated framework for measuring various aspects of network security. We first outline our principles andmethodologies. We then describe concrete examples to buildintuitions. Finally, we present our formal framework. It is our belief that metrics developed based on the proposed framework will lead to novel quantitative approaches to vulnerability analysis, network hardening, and attack response.

O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O


The SAMI Galaxy Survey: A prototype data archive for Big Science exploration ? We describe the data archive and database for the SAMI Galaxy Survey, an ongoing observational program that will cover ?3400 galaxies with integral-field (spatially-resolved) spectroscopy. Amounting to some three million spectra, this is the largest sample of its kind to date. The data archive and built-in query engine use the versatile Hierarchical Data Format (HDF5), which precludes the need for external metadata tables and hence the setup and maintenance overhead those carry. The code produces simple outputs that can easily be translated to plots and tables, and the combination of these tools makes for a light system that can handle heavy data. This article acts as a contextual companion to the SAMI Survey Database source code repository, samiDB, which is freely available online and written entirely in Python. We also discuss the decisions related to the selection of tools and the creation of data visualisation modules. It is our aim that the work presented in this articledescriptions, rationale, and source codewill be of use to scientists looking to set up a maintenance-light data archive for a Big Science data load.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

astronomical databases: miscellaneous
surveys
virtual observatory tools
methods: miscellaneous


keyboard entry - can it be simplified? The present keyboard arrangement cannot be defended as comfortable, logically arranged, or optimized for human efficiency. Information theory based experiments suggest measures for alternative arrangements. Character sets used in different tasks can be expected to yield different optimal key locations. New tasks are introducing new characters and changing the frequency of selected old ones. Numerous alternative arrangements for alphanumeric fingered entry have been designed, but none are supported by conclusive testing. The amateur keyboard user far outnumbers the professional. Computer entry and word-processors are overtaking the simple typewriter as common alphanumeric stroke entry devices. Compromise and selection of a simplified keyboard that is compatible with present mechanical and electronic designs is advocated.

B O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O B O O O O O O O O O O O O B O O O O O O O O O O O


Modeling the frequency response of p(+)InP/n(-)InGaAS/n(+) InP photodiodes with an arbitrary electric field profile Purpose - This paper seeks to present a numerical model which is used to obtain the transit time limited frequency response of p-i-n photodiodes with an arbitrary electric field profile. The effect of the absorption layer width and bias voltage on the frequency response is also investigated. Design/methodology/approach - The absorption region is divided into any desired number of layers and the continuity equations are solved, for each layer, assuming that within the layer the carriers' drift velocities are constant. The frequency response of the multilayer structure is calculated from the response of each layer using matrix algebra. Findings - The numerical results agree well with those from the experiment. It is seen that the results, assuming the saturation drift velocities, are usually overestimated especially for low values of the bias voltage or high values of the absorption region width. Research limitations/implications - The numerical method under study neglects the capacitive effects which may determine the frequency response of very short devices. In this case a more complete treatment, including also the displacement current, should be carried out. Practical implications - Software development for the design of multilayer photodiodes with optimized frequency response. Originality/value - To the best of one's knowledge this is an original report of the application of this numerical method to the calculation of the frequency response of p-i-n photodiodes. The numerical method, being able to treat in a simple way multilayer structures with any electric field profile, is a very powerful tool in the development of software for the design of efficient photodiodes of various types.

O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O


A modification of the artificial compressibility algorithm with improved convergence characteristics The artificial compressibility algorithm has a significant drawback in the difficulty of choosing the artificial compressibility parameter, improper choice of which leads either to slow convergence or divergence. A simple modification of the equation for pressure in the artificial compressibility algorithm which removes the difficulty of choosing the artificial compressibility parameter is proposed. It is shown that the choice of the relaxation parameters for the new algorithm is relatively straightforward, and that the same values can be used to provide robust convergence for a range of application problems. This new algorithm is easily parallelized making it suitable for computations such as direct numerical simulation (DNS) which require the use of distributed memory machines. Two key benchmark problems are studied in evaluating the new algorithm: DNS of a fully developed turbulent channel flow, and DNS of a driven-cavity flow, using both explicit and implicit time integration schemes. The new algorithm is also validated for a more complex flow configuration of turbulent flow over a backward-facing step, and the computed results are shown to be in good agreement with experimental data and previous DNS work. Copyright 2007 John Wiley & Sons, Ltd.

O O O O B I O O B I O O B I O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

artificial compressibility
improved convergence


Thin films of CoSi2 on Si1?yCy substrate layers The reaction of Co with epitaxial Si1?yCy(001) films is investigated with regard to dependence on annealing temperature and C concentration y. Resistance measurements and RBS analysis reveal a small increase in the disilicide formation temperature. The electrical properties are very similar for thin CoSi2 films grown at 650C on Si0.999C0.001 and on Si. Whereas the CoSi2 is fully polycrystalline on Si(001), partially oriented CoSi2 has been observed on C-containing substrate layers. An increase of the number of epitaxially grown CoSi2 crystallites has been observed with increasing C concentration.

B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Extraction, matching, and pose recovery based on dominant rectangular structures Man-made environments possess many regularities which can be efficiently exploited for image-based rendering as well as robotic navigation and localization tasks. In this paper, we present an approach for automatic extraction of dominant rectangular structures from a single view and show how they facilitate the recovery of camera pose, planar structure, and matching across widely separated views. In the presented approach, the rectangular hypothesis formation is based on a higher-level information encoded by the presence of orthogonal vanishing directions, the dominant rectangular structures can be detected and matched despite the presence of multiple repetitive structures often encountered in a variety of buildings. Different stages of the approach are demonstrated on various examples of images of indoor and outdoor structured environments.

O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

model-based reconstruction
wide-baseline matching


ECG compression method using Lorentzian functions model An ECG compression algorithm using a combination of Lorentzian functions model is proposed in this paper. In order to estimate the parameters of the Lorentzian functions, the discrete Fourier transform (DFT) is first applied to a mean removed ECG signal from which only the most significant DFT coefficients are retained. The obtained coefficients are, then modeled as the sum of a given number of superimposed exponentially damped sinusoids (EDS), commonly identified by their amplitudes, real damping factors, frequencies and initial phases. Finally, these EDS parameters are estimated, using SVD method, then coded. The algorithm has been tested for its coding efficiency and reconstruction capability by applying it to several popular, benchmark ECG signals. Encouraging results have been obtained.

B I O O B I O O B I O O O O O B I O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

ecg compression
svd
lorentzian functions
exponentially damped sinusoids


Reasoning of Feature Models from Derived Features When using product lines, whose variability models are based on derived features, e.g., Simulink variant objects, the dependencies among the features are only described implicitly. This makes it difficult to verify the mapping of the features to the solution space and to create a comprehensive overview of the feature dependencies like in a feature model. In this paper, an OWL-based approach is presented, which permits the automatic verification of the feature mapping and an automatic feature model synthesis for derived features using OWL reasoning and formal concept analysis.

B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O B I I O O O O B B O B I I

verification
owl
reasoning
feature model synthesis
formal concept analysis

algorithms
derived feature
variant object


Efficient and Generalized Pairing Computation on Abelian Varieties In this paper, we propose a new method for constructing a bilinear pairing over (hyper)elliptic curves, which we call the R-ate pairing. This pairing is a generalization of the Ate and Ate, pairing, and can be computed more efficiently. Using the R-ate pairing, the loop length in Miller's algorithm can be as small as log(r(1/o(k))) for some pairing-friendly elliptic curves which have not reached this lower bound. Therefore, we obtain savings of between 29% and 69% in overall costs compared to the Ate, pairing. On supersingular hyperelliptic curves of genus 2, we show that this approach makes the loop length in Miller's algorithm shorter than that of the Ate pairing.

O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O B I O O B I O O O O O O O O O O O O O O O O O O O O B I

ate pairing
elliptic curves
hyperelliptic curves


efficient implementation of a planar point location method Kirkpatrick's method is extensively used to solve planar point location problem. In this paper we develop an efficient implementation for Kirkpatrick's method by developing an efficient version of the algorithms associated with the method. Efficient data structures for these more efficient algorithms are formulated. Computational experiments that were conducted verify the practical efficiency of our proposed implementation.

O O O O O O O O O O O O O O O B I I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Evaluation of different features of an eHealth application for personalized illness management support: Cancer patients' use and appraisal of usefulness Objective: The purpose of this paper was to describe patients' use of a multi-component eHealth application, WebChoice, designed to support cancer patients in illness management. With WebChoice patients can monitor their symptoms, obtain individually tailored, evidence-based self-management support, ask questions to a clinical nurse specialist, communicate with other patients in a Forum, and use a diary. Methods: To better understand what components were most helpful, we analyzed user logs of breast and prostate cancer patients who participated in the experimental arm of an RCT to test effects of WebChoice on clinical outcomes. Patients could freely use the system for one year. After 6 months into the study, participants received questionnaires asking about reasons for using the different WebChoice components and their usefulness. Results: 103 (64%) patients actively used WebChoice, on average 60 times. The Forum and asking questions to the nurse were used the most, yet there were large individual variations in use patterns. Also, patients used different WebChoice components for different reasons. The e-mail communication with nurses was valued highest. Discussion: Differences were found between breast and prostate cancer patients and between patients with a first time diagnosis and metastases or recurrences. The large variations among patients in their use of WebChoice components demonstrate that patients' needs for support vary. Conclusion: The use patterns and patients' appraisals of usefulness in this study provide important insights into cancer patients' information and communication behavior that are important for further improvements and the design of eHealth applications for illness management support. (C) 2013 Elsevier Ireland Ltd. All rights reserved.

O O O O O O B O O O O O O B O O O O O B O O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O B O O O O O O O B O O O O O O O O O O O O O O O B O O O O O O O O O O O O O


On the relative impact of subgrid-scale modelling and conjugate heat transfer in LES of hot jets in cross-flow over cold plates This work describes numerical simulations of a hot jet in cross-flow with applications to anti-ice systems of aircraft engine nacelles. Numerical results are compared with experimental measurements obtained at ONERA to evaluate the performances of LES in this industrial context. The combination of complex geometries requiring unstructured meshes and high Reynolds number does not allow the resolution of boundary layers so that wall models must be employed. In this framework, the relative influence of subgrid-scale modelling and conjugate heat transfer in LESs of aerothermal flows is evaluated. After a general overview of the transverse jet simulation results, a LES coupled with a heat transfer solver in the walls is used to show that thermal boundary conditions at the wall have more influence on the results than subgrid scale models. Coupling fluid flow and heat transfer in solids simulations is the only method to specify their respective thermal boundary conditions. Copyright (C) 2011 John Wiley & Sons, Ltd.

O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

fluid-structure coupling
large eddy simulation
hot jet in cross-flow
subgrid-scale modelling


SQUIRE: Sequential pattern mining with quantities Discovering sequential patterns is an important problem for many applications. Existing algorithms find qualitative sequential patterns in the sense that only items are included in the patterns. However, for many applications, such as business and scientific applications, quantitative attributes are often recorded in the data, which are ignored by existing algorithms. Quantity information included in the mined sequential patterns can provide useful insight to the users. In this paper, we consider the problem of mining sequential patterns with quantities. We demonstrate that naive extensions to existing algorithms for sequential patterns are inefficient, as they may enumerate the search space blindly. To alleviate the situation, we propose hash filtering and quantity sampling techniques that significantly improve the performance of the naive extensions. Experimental results confirm that compared with the naive extensions, these schemes not only improve the execution time substantially but also show better scalability for sequential patterns with quantities. (c) 2006 Elsevier Inc. All rights reserved.

O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


A parallel and non-parallel genetic algorithm for deconvolution of NMR spectra peaks Interpreting high resolution nuclear magnetic resonance (NMR) spectra of complex samples is investigated by the use of real valued parallel and nonparallel genetic algorithm based on stochastic search procedure. The population-centric crossover operators were used in real coded genetic algorithm (RCGA) based on some probability distributions. This paper also presents parallel genetic algorithms computations with different genetic immigration operators. Different results were found with respect to the problems, even at the different stages of the genetic process in the same problem. It is observed that the grid and centralized type genetic immigration (island models) were effective on the global optimization. The parallel and non-parallel algorithms were also applied for solving some multi-modal test problems. It is found that the island models achieve superior performance on multi-modal test problems and on deconvolution of complex NMR spectra. (C) 2013 Elsevier B.V. All rights reserved.

O O O O O O O O O B O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O

parallel genetic algorithm
peak deconvolution
experimental chemistry data processing


Motion estimation of elastic articulated objects from points and contours with volume invariable constraint This paper presents a model of elastic articulated objects based on revolving conic surface and a method of model-based motion estimation. The model includes 3D object skeleton and deformable surfaces that can represent the deformation of human body surfaces. In each limb, surface deformation is represented by adjusting one or two deformation parameters. Then, the 3D deformation parameters are determined by corresponding 2D image points and contours with volume invariable constraint from a sequence of stereo images. The 3D motion parameters are estimated based on the 3D model. The algorithm presented in this paper includes model-based parameter estimation of motion and parameter determination of deformable surfaces.

B I O B I I O O O O O O O O O O O O O O B I I O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

elastic articulated objects
motion estimation

human body modeling
revolving conic surfaces


accurate and efficient gate-level parametric yield estimation considering correlated variations in leakage power and performance Increasing levels of process variation in current technologies have a major impact on power and performance, and result in parametric yield loss. In this work we develop an efficient gate-level approach to accurately estimate the parametric yield defined by leakage power and delay constraints, by finding the joint probability distribution function (jpdf) for delay and leakage power. We consider inter-die variations as well as intra-die variations with correlated and random components. The correlation between power and performance arise due to their dependence on common process parameters and is shown to have a significant impact on yield in high-frequency bins. We also propose a method to estimate parametric yield given the power/delay jpdf that is much faster than numerical integration with good accuracy. The proposed approach is implemented and compared with Monte Carlo simulations and shows high accuracy, with the yield estimates achieving an average error of 2\%.

O O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O


Optimal online pricing with network externalities We study the optimal pricing strategy for profit maximization in presence of network externalities where a decision to buy a product depends on the price offered to the buyer and also on the set of her friends who have already bought that product. We model the network influences by a weighted graph where the utility of each buyer is the sum of her initial value on the product, and the linearly additive influence from her friends. We assume that the buyers arrive online and the seller should offer a price to each buyer when she enters the market. We also take into account the manufacturing cost. In this paper, we first assume that the monopolist defines a unique price for the product and commits to it for all buyers. In this case, we present an FPTAS algorithm that approximates the optimal price with a high probability. We also prove that finding the optimum price is NP-hard. Second, we consider a market with positive network externalities and assume that the monopolist could offer a private price to each customer. We prove that this problem is also hard to approximate for linear influences. On the positive side, we present a polynomial time algorithm for the problem when influences are symmetric. At last, we show that the seller has more ability to extract influences with price discrimination. (C) 2011 Elsevier B.V. All rights reserved.

O O B O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

social networks
approximation algorithm
online algorithm


Classifying technological knowledge for presentation to mechanical engineering designers In this paper, we explore various options to classify technological knowledge for mechanical engineering designers. Classification is needed when technological knowledge is presented to designers in an automated knowledge management system (for example, a database that can be accessed by designers through the Internet). In particular, we draw from philosophy of technology, history of technology, and design methodology, to see what classifications can be made. It is not known whether such theoretical classifications are recognised by designers. In the empirical part of our study, we have submitted a number of optional classifications to active mechanical engineering designers to see what classification they would prefer as the basis for an automated knowledge-based system on the Internet. The outcome was that they recognised a classification that had been developed in the context of philosophical and historical studies, and even preferred that compared to more traditional disciplinary classifications.

O B I O O O O O O O O O O O O O O O B I O O O O B O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O

epistemology
product design
knowledge-based systems


MODEL-FREE RECONFIGURATION MECHANISM FOR FAULT TOLERANCE The problem of fault tolerant control is studied from the behavioral point of view. In this mathematical framework, the concept of interconnection among the variables describing the system is a key point. The problem is that the behavior we intend to control is not known. Therefore, we are interested in designing a fault accommodation scheme for an unknown behavior through an appropriate behavioral interconnection. Here we deal simply with the trajectories that are generated by the system in real time. These trajectories determine the behavior of a system in various (faulty/healthy) modes. Based on the desired interconnected behavior, only the trajectories that obey certain laws are selected. These laws, representing the desired behavior, can indeed be achieved by a regular interconnection. Thus, when the trajectories do not belong to a certain desired behavior, it is considered to be due to the occurrence of a fault in the system. The vantage point is that the fault tolerant control problem now becomes completely a model-free scheme. Moreover, no explicit fault diagnosis module is required in our approach. The proposed fault tolerance mechanism is illustrated on an aircraft during the landing phase.

O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

control performance
behavioral theory
switching control


Type-2 Fuzzy Formation Control for Collision-Free Multi-Robot Systems The main goal of this paper is to investigate the leader-following formation control of multi-robot systems. The problem of collision avoidance is considered as well. According to the graph-theoretic concepts and locally distributed information, an interval type-2 neural fuzzy formation controller is designed with the capability of on-line learning. The learning rules of controller parameters can be derived from the gradient descent method. To avoid collisions between robots, a fuzzy separation controller is proposed such that the local minimum problem can be solved. Both static and dynamic leaders are discussed for performance validations. Simulation and experimental results indicate that the proposed fuzzy formation and separation control can provide better formation responses compared to conventional consensus formation and potential-based collision-avoidance algorithms.

O O B I O O O O O O O O O O O O O O O B I O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

multi-robot systems
interval type-2 fuzzy control


A soft sensor method based on values predicted from multiple intervals of time difference for improvement and estimation of prediction accuracy Soft sensors are widely used to estimate process variables that are difficult to measure online. However, their predictive accuracy gradually decreases with changes in the state of the plants. We have been constructing soft sensor models based on the time difference of an objective variable, y, and that of explanatory variables (time difference models) for reducing the effects of deterioration with age such as the drift without model reconstruction. In this paper, we have attempted to improve and estimate the prediction accuracy of time difference models, and proposed to handle multiple y-values predicted from multiple intervals of time difference. A weighted average is a final predicted value and the standard deviation is an index of its prediction accuracy. This method was applied to real industrial data and then, could predict more number of data with higher predictive accuracy and estimate the prediction errors more accurately than traditional ones. (C) 2011 Elsevier B.V. All rights reserved.

O B I O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O B I O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

prediction error
applicability domain
distance to model
ensemble prediction


Elastoplastic meshless integral method In this paper, the meshless integral method based on regularized boundary integral equation [A. Bodin, J. Ma, X.J. Xin, P. Krishnaswami, A meshless integral method based on regularized boundary integral equation, Comput. Methods Appl. Mech. Engrg. 195 (2006) 62586286] has been extended to elastoplastic materials. In the formulation, the domain of interest is populated with a set of nodes using an automatic node generation algorithm. The sub-domain and support domain associated with each node are also generated automatically using algorithms that have been developed for this purpose. The governing integral equation is obtained from the weak form of elastoplasticity over a local sub-domain, and the moving least-squares approximation is used for meshless function approximation. The constitutive law is the small deformation, rate-independent flow theory based on von Mises yielding criterion with isotropic hardening. The generalized collocation method is employed to enforce the essential boundary conditions exactly, which is simple and computationally efficient. Natural boundary conditions are incorporated in the system governing equation and require no special handling. The solution algorithm for elastoplastic analysis is discussed in detail. The proposed method can handle any prescribed loading profile, including unloading and reversed loading. Numerical examples show that the elastoplastic integral meshless method is accurate and robust.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O

local boundary integral equation
moving least-squares approximation
subtraction method
singularity removal


MRI of hemangioblastoma in the conus medullaris Hemangioblastoma of the conus medullaris with MRI has not been reported before. A 75-year-old man had a history of falling due to weakness of his left lower limb. MRI revealed a well-defined oval mass in the conus medullaris. The tumor had an isointense signal relative to spinal cord on T1-weighted images, hyperintense signal areas intermixed with punctate spots of hypointensity on T2-weighted images, and heterogeneous obvious enhancement on gadolinium-enhanced T1-weighted images. Associated abnormally tortuous vessels were noted in the dura proximal to the tumor. Histological findings were compatible with the diagnosis of hemangioblastoma. Hemangioblastoma should be included in the differential diagnosis in patients with an enhancing tumor and adjacent engorged vessels of the spinal cord.

O O B O O B I B O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B B O O O O O O O O O O O O O O O O O O O O O

magnetic resonance imaging (mri)
spinal cord tumors


Determinants of customer repurchase intention in online shopping Purpose - The purpose of this paper is to understand customers' repurchase intentions in online shopping. This study extends the technology acceptance model (TAM) by introducing e-service quality dimensions, trust and enjoyment in the development of a theoretical model to study customers' repurchase intentions within the context of online shopping. Design/methodology/approach - Data collected from 360 PCHome online shopping customers provides strong support for the proposed research model. PLS (partial least squares, PLS-Graph version 3.0) is used to analyse the measurement and structural models. Findings - The study shows that trust, perceived ease of use, perceived usefulness and enjoyment are significant positive predictors of customers' repurchase intentions. Research limitations/implications - The data are collected from a single online shopping store the generalisation of the model and findings to other online stores requires additional research. Our findings imply that the five dimensions of e-service quality are possibly among the most important antecedents of customers' trust in online vendors. Practical implications - Online vendors should ensure that they provide adequate utilitarian and hedonic value for customers instead of focusing on just one of these aspects in their web site development. Originality/value - Customer loyalty is critical to the online vendor's survival and success. The study provides evidence that online trust is built through order fulfilment, privacy, responsiveness and contact.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O

internet shopping
consumer behaviour
customer services quality


Embedding-Based Subsequence Matching in Time-Series Databases We propose an embedding-based framework for subsequence matching in time-series databases that improves the efficiency of processing subsequence matching queries under the Dynamic Time Warping (DTW) distance measure. This framework partially reduces subsequence matching to vector matching, using an embedding that maps each query sequence to a vector and each database time series into a sequence of vectors. The database embedding is computed offline, as a preprocessing step. At runtime, given a query object, an embedding of that object is computed online. Relatively few areas of interest are efficiently identified in the database sequences by comparing the embedding of the query with the database vectors. Those areas of interest are then fully explored using the exact DTW-based subsequence matching algorithm. We apply the proposed framework to define two specific methods. The first method focuses on time-series subsequence matching under unconstrained Dynamic Time Warping. The second method targets subsequence matching under constrained Dynamic Time Warping (cDTW), where warping paths are not allowed to stray too much off the diagonal. In our experiments, good trade-offs between retrieval accuracy and retrieval efficiency are obtained for both methods, and the results are competitive with respect to current state-of-the-art methods.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

algorithms
performance
theory
embedding methods
similarity matching
nearest neighbor retrieval
non-euclidean spaces
nonmetric spaces


Training a feed-forward network with incomplete data due to missing input variables Data available for training a neural network may be deficient not only in quantity of data but entire independent variables with their data may be missing such as is often the situation for software engineering data. This may cause the relation based on the available data to exhibit the property of one-to-many (o-m) valuedness or almost o-m valuedness. Multiplayer perceptrons or feed-forward network however are generally trained to represent functions or m-o mappings. The solution consists of adding another input to the standard feed-forward network and of modifying the training algorithm to allow for determination of this input for which no training data is available. If the values for the additional input are restricted to a discrete set then they may be perceived as cluster identifiers and the training method may be perceived as another form of clustering or segmentation of the input. If the missing input variable is assumed to have a finite number of values the method proposed here may be compared to mixture of experts and mixture density networks except that the proposed method is more direct solution. The modified feed-forward network and training method has been successfully applied to several examples.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

feed forward neural networks
relations
one-to-many mappings
data segmentation
many-valued functions
missing inputs
incomplete training data


P2P IP Telephony over wireless ad-hoc networks A smart approach on super node admission This paper presents a new strategy to form P2P IP Telephony overlay for wireless ad-hoc networks. In the proposed strategy a structured P2P system is considered where some nodes, called super-nodes, with higher capacity form the overlay and provide registry and call routing services. As selection and admission of new super-nodes in wireless ad-hoc networks is more challenging than backbone networks, we define the strategies to select and admit new super-nodes into the overlay. On one hand, scarce resources and fluctuating link quality demand additional criteria than just node computing resources for super-nodes selection. On the other hand, the indiscriminate increase in super-node number can raise the call session setup delay and degrade the quality. This is due to the relaying of packets across multiple wireless links. In this paper, we first define the criteria to select super-nodes and then the major part of the paper is dedicated to defining the required strategies to admit new super-nodes. Our admission strategies add new super-nodes to the system whenever they are required. Since the strategy does not simply admit all eligible super-node candidates, this ensures control over the number of super-nodes and keeps the session setup delay within to the required service level threshold. We define a queuing network to model our system and evaluate the efficacy of our admission strategies with intensive simulations. Furthermore, we have implemented a P2P IP Telephony system that operates on wireless ad-hoc networks and validated the performance of our admission strategies on this real platform.

B B I O O O O O O O O O O O O O O O O O O O B B I O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B B I O O O O O O O O O O O O O O O O O O O

wireless ad-hoc networks
distributed hash table


Nonlocal image and movie denoising Neighborhood filters are nonlocal image and movie filters which reduce the noise by averaging similar pixels. The first object of the paper is to present a unified theory of these filters and reliable criteria to compare them to other filter classes. A CCD noise model will be presented justifying the involvement of neighborhood filters. A classification of neighborhood filters will be proposed, including classical image and movie denoising methods and discussing further a recently introduced neighborhood filter, NL-means. In order to compare denoising methods three principles will be discussed. The first principle, "method noise", specifies that only noise must be removed from an image. A second principle will be introduced, "noise to noise", according to which a denoising method must transform a white noise into a white noise. Contrarily to "method noise", this principle, which characterizes artifact-free methods, eliminates any subjectivity and can be checked by mathematical arguments and Fourier analysis. "Noise to noise" will be proven to rule out most denoising methods, with the exception of neighborhood filters. This is why a third and new comparison principle, the "statistical optimality", is needed and will be introduced to compare the performance of all neighborhood filters. The three principles will be applied to compare ten different image and movie denoising methods. It will be first shown that only wavelet thresholding methods and NL-means give an acceptable method noise. Second, that neighborhood filters are the only ones to satisfy the "noise to noise" principle. Third, that among them NL-means is closest to statistical optimality. A particular attention will be paid to the application of the statistical optimality criterion for movie denoising methods. It will be pointed out that current movie denoising methods are motion compensated neighborhood filters. This amounts to say that they are neighborhood filters and that the ideal neighborhood of a pixel is its trajectory. Unfortunately the aperture problem makes it impossible to estimate ground true trajectories. It will be demonstrated that computing trajectories and restricting the neighborhood to them is harmful for denoising purposes and that space-time NL-means preserves more movie details.

O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Anytime propagation algorithm for min-based possibilistic graphs This paper proposes a new anytime possibilistic inference algorithm for min-based directed networks. Our algorithm departs from a direct adaptation of probabilistic propagation algorithms since it avoids the transformation of the initial network into a junction tree which is known to be a hard problem. The proposed algorithm is composed of several, local stabilization, procedures. Stabilization procedures aim to guarantee that local distributions defined on each node are coherent with respect to those of its parents. We provide experimental results which, for instance, compare our algorithm with the ones based on a direct adaptation of probabilistic propagation algorithms.

B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


The influence of task and gender on search and evaluation behavior using Google To improve search engine effectiveness, we have observed an increased interest in gathering additional feedback about users information needs that goes beyond the queries they type in. Adaptive search engines use explicit and implicit feedback indicators to model users or search tasks. In order to create appropriate models, it is essential to understand how users interact with search engines, including the determining factors of their actions. Using eye tracking, we extend this understanding by analyzing the sequences and patterns with which users evaluate query result returned to them when using Google. We find that the query result abstracts are viewed in the order of their ranking in only about one fifth of the cases, and only an average of about three abstracts per result page are viewed at all. We also compare search behavior variability with respect to different classes of users and different classes of search tasks to reveal whether user models or task models may be greater predictors of behavior. We discover that gender and task significantly influence different kinds of search behaviors discussed here. The results are suggestive of improvements to query-based search interface designs with respect to both their use of space and workflow.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

web search
information retrieval
humancomputer interaction
information seeking


Dual sourcing using capacity reservation and spot market: Optimal procurement policy and heuristic parameter determination This contribution focuses on the cost-effective management of the combined use of two procurement options: the short-term option is given by a spot market with random price, whereas the long-term alternative is characterized by a multi period capacity reservation contract with fixed purchase price and reservation level. A reservation cost, proportional with the reservation level, has to be paid for the option of receiving any amount per period up to the reservation level. A long-term decision has to be made regarding the reserved capacity level, and then it has to be decided period by period which quantities to procure from the two sources. Considering the multi-period problem with stochastic demand and spot price, the structure of the optimal combined purchasing policy is derived using stochastic dynamic programming. Exploiting these structural properties, an advanced heuristic is developed to determine the respective policy parameters. This heuristic is compared with two rolling-horizon approaches which use the one-period and two-period optimal solution. A comprehensive numerical study reveals that the approaches based on one-period and two-period solutions have considerable drawbacks, while the advanced heuristic performs very well compared to the optimal solution. Finally, by exploiting our numerical results we give some insights into the systems behavior under problem parameter variations.

B I O B I O B I O B I O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

dual sourcing
capacity reservation
spot market
procurement policy
stochastic dynamic programming


Quantitative structure-retention relationships for gas chromatographic retention indices of alkylbenzenes with molecular graph descriptors Quantitative structure-retention relationships (QSRR) represent statistical models that quantify the connection between the molecular structure and the chromatographic retention indices of organic compounds, allowing the prediction of retention indices of novel, not yet synthesized compounds, solely from their structural descriptors. Using multiple linear regression, QSRR models for the gas chromatographic Kovats retention indices of 129 alkylbenzenes are generated using molecular graph descriptors. The correlational ability of structural descriptors computed from 10 molecular matrices is investigated, showing that the novel reciprocal matrices give numerical indices with improved correlational ability. A QSRR equation with 5 graph descriptors gives the best calibration and prediction results, demonstrating the usefulness of the molecular graph descriptors in modeling chromatographic retention parameters. The sequential orthogonalization of descriptors suggests simpler QSRR models by eliminating redundant structural information.

O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I I O O O O O O O O O

gas chromatographic kovats retention index


Derandomized Constructions of k-Wise (Almost) Independent Permutations Constructions of k-wise almost independent permutations have been receiving a growing amount of attention in recent years. However, unlike the case of k-wise independent functions, the size of previously constructed families of such permutations is far from optimal. This paper gives a new method for reducing the size of families given by previous constructions. Our method relies on pseudorandom generators for space-bounded computations. In fact, all we need is a generator, that produces "pseudorandom walks" on undirected graphs with a consistent labelling. One such generator is implied by Reingold's log-space algorithm for undirected connectivity (Reingold/Reingold et al. in Proc. of the 37th/38th Annual Symposium on Theory of Computing, pp. 376-385/457-466, 2005/2006). We obtain families of k-wise almost independent permutations, with an optimal description length, up to a constant factor. More precisely, if the distance from uniform for any k tuple should be at most delta, then the size of the description of a permutation in the family is O(kn + log 1/delta).

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

pseudo-randomness
card shuffling
block ciphers
random walk


Optical mapping in plant comparative genomics Optical mapping has been widely used to improve de novo plant genome assemblies, including rice, maize, Medicago, Amborella, tomato and wheat, with more genomes in the pipeline. Optical mapping provides long-range information of the genome and can more easily identify large structural variations. The ability of optical mapping to assay long single DNA molecules nicely complements short-read sequencing which is more suitable for the identification of small and short-range variants. Direct use of optical mapping to study population-level genetic diversity is currently limited to microbial strain typing and human diversity studies. Nonetheless, optical mapping shows great promise in the study of plant trait development, domestication and polyploid evolution. Here we review the current applications and future prospects of optical mapping in the field of plant comparative genomics.

B I O O B I B I O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O B I


Statistical geometry representation for efficient transmission and rendering Traditional geometry representations have focused on representing the details of the geometry in a deterministic fashion. In this article we propose a statistical representation of the geometry that leverages local coherence for very large datasets. We show how the statistical analysis of a densely sampled point model can be used to improve the geometry bandwidth bottleneck, both on the system bus and over the network as well as for randomized rendering, without sacrificing visual realism. Our statistical representation is built using a clustering-based hierarchical principal component analysis (PCA) of the point geometry. It gives us a hierarchical partitioning of the geometry into compact local nodes representing attributes such as spatial coordinates, normal, and color. We pack this information into a few bytes using classification and quantization. This allows our representation to directly render from compressed format for efficient remote as well as local rendering. Our representation supports both view-dependent and on-demand rendering. Our approach renders each node using quasi-random sampling utilizing the probability distribution derived from the PCA analysis. We show many benefits of our approach: (1) several-fold improvement in the storage and transmission complexity of point geometry; (2) direct rendering from compressed data; and (3) support for local and remote rendering on a variety of rendering platforms such as CPUs, GPUs, and PDAs.

O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O O B O O O O O O O

computer graphics
point-based rendering
view-dependent rendering
progressive transmission
network graphics
quasi-random numbers
programmable gpu


Efficient arbitrated quantum signature and its proof of security In this paper, an efficient arbitrated quantum signature scheme is proposed by combining quantum cryptographic techniques and some ideas in classical cryptography. In the presented scheme, the signatory and the receiver can share a long-term secret key with the arbitrator by utilizing the key together with a random number. While in previous quantum signature schemes, the key shared between the signatory and the arbitrator or between the receiver and the arbitrator could be used only once, and thus each time when a signatory needs to sign, the signatory and the receiver have to obtain a new key shared with the arbitrator through a quantum key distribution protocol. Detailed theoretical analysis shows that the proposed scheme is efficient and provably secure.

O O B I O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Classification and optimization of potentially runaway processes using topology tools Fast and strongly exothermic reactions can exhibit a well-known phenomenon called "thermal runaway". To identify high productivity and safe conditions for these reactions, with particular reference to industrial semibatch processes carried out using both isothermal and isoperibolic temperature control mode, a dedicated classification/optimization software has been implemented. This software is able to both classify a set of operating parameters from the thermal stability viewpoint and identify the optimum reacting/synthesis conditions using a topological criterion that binds the so-called "QFS region", where reactants accumulation is low and all the heat released is readily removed by the cooling equipment. During the search for system optimum a number of safety and quality constraints can be taken into account. The software reliability, in terms of both classification and optimization ability, has been tested using both laboratory and industrial scale experimental data. Obtained results confirm a good agreement between theoretical predictions and experimental evidence. (C) 2013 Elsevier Ltd. All rights reserved.

O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

loss of control
chemical reactors
safe optimization


Using multilayer perceptrons as receptive fields in the design of neural networks In this paper, we propose a new neural network architecture based on a family of referential multilayer perceptrons (RMLPs) that play a role of generalized receptive fields. In contrast to standard radial basis function (RBF) neural networks, the proposed topology of the network offers a considerable level of flexibility as the resulting receptive fields are highly diversified and capable of adjusting themselves to the characteristics of the locally available experimental data. We discuss in detail a design strategy of the novel architecture that fully exploits the modeling capabilities of the contributing RMLPs. The strategy comprises three phases. In the first phase, we form a blueprint of the network by employing a specialized version of the commonly encountered fuzzy C-means (FCM) clustering algorithm, namely the conditional (context-based) FCM. In this phase our intent is to generate a collection of information granules (fuzzy sets) in the space of input and output variables, narrowed down to some certain contexts. In the second phase, based upon a global view at the structure, we refine the inputoutput relationships by engaging a collection of RMLPs where each RMLP is trained by using the subset of data associated with the corresponding context fuzzy set. During training each receptive field focuses on the characteristics of these locally available data and builds a nonlinear mapping in a referential mode. Finally, the connections of the receptive fields are optimized through global minimization of the linear aggregation unit located at the output layer of the overall architecture. We also include a series of numeric experiments involving synthetic and real-world data sets which provide a thorough comparative analysis with standard RBF neural networks.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

conditional clustering
local modeling
neural receptive fields
radial basis function (rbf) networks
referential neural networks


Weighting for more: Enhancing characteristic-function based ICA with asymptotically optimal weighting ? ?? The CHaracteristic-function-Enabled Source Separation (CHESS) method for independent component analysis (ICA) is based on approximate joint diagonalization (AJD) of Hessians of the observations' empirical log-characteristic-function, taken at selected off-origin processing points. As previously observed in other contexts, the AJD performance can be significantly improved by optimal weighting, using the inverse of the covariance matrix of all of the off-diagonal terms of the target-matrices. Fortunately, this apparently cumbersome weighting scheme takes a convenient form under the assumption that the mixture is already nearly separated, e.g., following some initial separation. We derive covariance expressions for the Sample-Hessian matrices, and show that under the near-separation assumption, the weight matrix takes a nearly block-diagonal form, conveniently exploited by the recently proposed WEighted Diagonalization using Gauss itErations (WEDGE) algorithm for weighted AJD. Using our expressions, the weight matrix can be estimated directly from the dataleading to our WeIghTed CHESS (WITCHESS) algorithm. Simulation results demonstrate how WITCHESS can lead to significant performance improvement, not only over unweighted CHESS, but also over other ICA methods.

O O O O O O B O O B I O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O

hessians of the log-characteristic function


Interoperation among agent-based information systems through a communication acts ontology ? Information technology is evolving from focusing on local systems to encompassing a more global interaction among multiple systems in enterprises and communities. On the one hand, new advances in the area of network communications have facilitated in some way the intercommunication among heterogeneous information systems located at different places. However, what is still missing is the possibility of a real and efficient interoperation among those systems in an open environment as the one favoured by Internet. On the other hand, agent technology provides platforms where cooperative work of information systems is concernable because of the software agents working on behalf of these information systems. But, nowadays that cooperation is in general restricted and requires a laborious a priori preparation. In this paper we present the features of a formal ontology that can play a relevant role in the development of a new kind of information systems interoperation frameworks. The ontology includes classes and properties for describing communication acts among agents. We claim that the communication acts ontology provides interoperability support due to the recognition of communication acts from one Agent Communication Language (acl) as instances of communication acts in another acl. Sometimes the comprehension will not be complete, but partial comprehension of the communication may be useful and preferable to the not understood answer given nowadays. Terms of the ontology are described as classes or properties using the Web Ontology Language owl.

O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O


a network coding scheme for svc streaming over wireless mesh network We argue that the conventional forward error correcting code (FEC) and retransmission solutions will become ineffective to transmit scalable video coding streaming in wireless mesh network (WMN) for the reason that video frame errors appear in bursts rather than random and the bad channel condition usually persists for a period in wireless channels. A novel SVC streaming cooperative transmission scheme is proposed in this paper. Our cooperative transmission scheme includes two stages among nodes in WMN. The first stage is selecting appropriate paths for the relevant SVC sub-layer streams and the second one is selecting nearby nodes to cache the network coding results of the adjacent sub-layer streams and retransmit the network coded packets to the user terminal for recovering the error packets. Simulation results are given to demonstrate the significant improvement of the SVC streaming reconstructive video quality.

O B I O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O B I O O O O O O O B I O O O O O O O B O O O O O O O O O O B O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O

cooperative transmission
network coding
svc
wmn


Identification of subsurface structures using electromagnetic data and shape priors We consider the inverse problem of identifying large-scale subsurface structures using the controlled source electromagnetic method. To identify structures in the subsurface where the contrast in electric conductivity can be small, regularization is needed to bias the solution towards preserving structural information. We propose to combine two approaches for regularization of the inverse problem. In the first approach we utilize a model-based, reduced, composite representation of the electric conductivity that is highly flexible, even for a moderate number of degrees of freedom. With a low number of parameters, the inverse problem is efficiently solved using a standard, second-order gradient-based optimization algorithm. Further regularization is obtained using structural prior information, available, e.g., from interpreted seismic data. The reduced conductivity representation is suitable for incorporation of structural prior information. Such prior information cannot, however, be accurately modeled with a gaussian distribution. To alleviate this, we incorporate the structural information using shape priors. The shape prior technique requires the choice of kernel function, which is application dependent. We argue for using the conditionally positive definite kernel which is shown to have computational advantages over the commonly applied gaussian kernel for our problem. Numerical experiments on various test cases show that the methodology is able to identify fairly complex subsurface electric conductivity distributions while preserving structural prior information during the inversion.

O O O O O O O O B I O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

electric conductivity estimation
reduced parameterization


Using Web resources to construct multilingual medical thesaurus for cross-language medical information retrieval Due to the language barrier, non-English users are unable to retrieve the most updated medical information from the U.S. authoritative medical websites, such as PubMed and MedlinePlus. However, currently, there is no any cross-language medical information retrieval (CLMIR) system that can help Chinese-speaking consumers cross the language barrier in finding useful English medical information. A few CLMIR systems utilize MeSH (Medical Subject Headings) to help overcome the language barrier. Unfortunately, the traditional Chinese version of MeSH is currently unavailable. In this paper, we employ a semi-automatic term translation method to construct a ChineseEnglish MeSH by exploiting abundant multilingual Web resources, including Web anchor texts and searchresult pages. Through this method, we have developed a ChineseEnglish Mesh Compilation System to assist knowledge engineers in compiling a ChineseEnglish medical thesaurus with more than 19,000 entries. Furthermore, this thesaurus has been used to develop a prototypical system for cross-language medical information retrieval, MMODE, which can help consumers retrieve top-quality English medical information using Chinese terms.

O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Improved bounds on partial derivatives of rational triangular Bezier surfaces This paper applies inequality skill, degree elevation of triangular Bezier surfaces and difference operators to deduce the bounds on first and second partial derivatives of rational triangular Bezier surfaces. Further more, we prove that the new bounds are tighter and more effective than the known ones. All the results are obviously helpful for further optimization of geometric design systems. (C) 2007 Elsevier Ltd. All rights reserved.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

rational bezier curve
rational triangular bezier surface
bivariate bernstein basis
bound on derivative


The effectiveness of groups recognizing patterns ? An experiment was conducted in which groups made resource allocation decisions while physically dispersed and supported with a shared virtual work surface (What You See Is What I SeeWYSIWIS). The task required groups to recognize patterns of information and collaborate to allocate their resources appropriately. The experimental treatment involved the use of a tool specifically designed to minimize the cognitive effort required to recognize and share patterns among group members. Dependent measures included outcome quality, time-to-decision, consensus of pattern recognition, and the number of resource allocation moves required to reach consensus. All groups received significant financial rewards in direct proportion to their outcome quality. Groups supported with the patternsharing tool had significantly higher outcome quality and significantly less resource movements. These results extend the theory of Recognition-Primed Decision-Making by applying it to groups.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

group support systems
collaboration
shared cognition


Factorial validity of problematic Internet use scales There exists a number of multidimensional measurement scales for problematic Internet use (PIU) with varying factor structures. This study reviews the factor analytic techniques used to develop these measures and discusses their implications for the factorial validity, particularly discriminant validity, of these PIU scales. To further illustrate these points, we reformulate the four-factor Online Cognition Scale into a more parsimonious two-factor measure (i.e., dependency and distraction) and demonstrate its factorial validity as well as robustness across student and working adult samples. Contributions of this research are discussed.

O O O B I I O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

internet addiction
computer attitudes
validation
factor analysis


Integration of a Voice Recognition System in a Social Robot Human-robot interaction (HRI)(1) is one of the main fields in the study and research of robotics. Within this field, dialogue systems and interaction by voice play an important role. When speaking about human-robot natural dialogue we assume that the robot has the capability to accurately recognize what the human wants to transmit verbally and even its semantic meaning, but this is not always achieved. In this article we describe the steps and requirements that we went through in order to endow the personal social robot Maggie, developed at the University Carlos III of Madrid, with the capability of understanding the natural language spoken by any human. We have analyzed the different possibilities offered by current software/hardware alternatives by testing them in real environments. We have obtained accurate data related to the speech recognition capabilities in different environments, using the most modern audio acquisition systems and analyzing not so typical parameters such as user age, gender, intonation, volume, and language. Finally, we propose a new model to classify recognition results as accepted or rejected, based on a second automatic speech recognition (ASR) opinion. This new approach takes into account the precalculated success rate in noise intervals for each recognition framework, decreasing the rate of false positives and false negatives.

O O O B I O O O B I O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I B O O O O O O O O O O O O O O O O O O O O O O O O O O O

asr
automatic speech recognition
dialogue
maggie
social robot
speech recognition
voice recognition

audition system
computing confidence score
human-computer interaction
human-robot interaction
microphone system
natural language processing
natural language understanding
personal robot
robot audition


Applications of agent-based systems in intelligent manufacturing: An updated review Agent technology has been recognized as a promising paradigm for next generation manufacturing systems. Researchers have attempted to apply agent technology to manufacturing enterprise integration, enterprise collaboration (including supply chain management and virtual enterprises), manufacturing process planning and scheduling, shop floor control, and to holonic manufacturing as an implementation methodology. This paper provides an update review on the recent achievements in these areas, and discusses some key issues in implementing agent-based manufacturing systems such as agent encapsulation, agent organization, agent coordination and negotiation, system dynamics, learning, optimization, security and privacy, tools and standards. (c) 2006 Elsevier Ltd. All rights reserved.

O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

agents
multi-agent systems
distributed manufacturing systems


An adaptive service selection method for cross-cloud service composition Cloud computing aims at providing elastic applications that can be scaled at runtime. In practice, traditional service composition methods are not flexible enough to changes in cross-cloud environment. In view of this challenge, an adaptive service selection method for cross-cloud service composition is proposed in this paper, by dynamically selecting proper services with near-optimal performance for adapting to changes in time. First, concretely speaking, the service selection and execution are modeled with Markov decision process to ensure flexibility. Second, service pair is defined, and the way to build service pairs set is proposed to predict the performance of candidate services. Third, the adaptive service selection algorithm is designed to select proper cloud services for changing cross-cloud environment. Finally, a case study for cross-cloud service composition and experiments are presented for validating the feasibility of our proposal. Concurrency and Computation: Practice and Experience, 2013.(c) 2013 Wiley Periodicals, Inc.

O B I I O O O B I O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O B I I O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O

adaptive service selection
service composition


WAMS Based Damping Control of Inter-area Oscillations Employing Energy Storage System This paper presents a systematic design procedure for a wide-area damping controller (WADC) employing Energy Storage Systems (ESSs). The WADC is aimed at enhancing the damping of multiple inter-area modes in a large scale power system. Firstly, geometric measures of controllability and obsevability are used to select the control locations for ESSs and most effective stabilizing signals, respectively. Then, the WADC coordinates these signals to achieve multiple-input-multiple-output (MIMO) controllers with the least Frobenius norm feedback gain matrix. The simulation results of frequency and time domains verify the effectiveness of the wide-area damping controller for various operating conditions. Furthermore, the robustness of the wide-area damping controller is also tested with respect to time delay and uncertainty of models.

O O B O O O O O B I O O O O O O O O O O O B O O O B I O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O B O O O B O O O O O O O O O O O O O

phasor measurement units
power system stability


Loop parallelization algorithms: From parallelism extraction to code generation In this paper, we survey loop parallelization algorithms, analyzing the dependence representations they use, the loop transformations they generate, the code generation schemes they require, and their ability to incorporate various optimizing criteria such as maximal parallelism detection, permutable loop detection, minimization of synchronizations, easiness of code generation, etc. We complete the discussion by presenting new results related to code generation and loop fusion for a particular class of multidimensional schedules called shifted linear schedules. We demonstrate that algorithms based on such schedules lead to simple codes.

O B I O O O O B I O O O O O O B I O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O B I O B I O O O O O O O O O O O O O O O O O O O O O O O

parallelization algorithms
loop fusion
code generation


Incorporating ObjectStab Library and Fuzzy Logic Toolbox for Design of Power System Damping Controller ObectStab is a general purpose simulation tool for power system stability studies developed by Modelica which is an object-oriented modeling language. It provides enough modeling flexibility to allow addition or modification of new power system components. This article describes an incorporated use of ObjectStab library and fuzzy logic toolbox in Matlab/Simulink to enhance the application of this library into fuzzy control design environment. The example provided here is the modeling of the static synchronous series compensator (SSSC) which is the new device developed in the ObjectStab. In addition, the interface of ObjectStab with Matlab/Simulink for an SSSC damping controller design by fuzzy logic toolbox is explained step by step. In fuzzy control design, a simple approach to extract membership functions and fuzzy logic control rules based on observed signals is presented. Simulation studies in a two-area four-generator power system confirm the effectiveness of the fuzzy controller of SSSC designed by the incorporated use of ObjectStab and fuzzy logic toolbox. (C) 2008 Wiley Periodicals, Inc. Comput Apt Eng Educ 16: 243-255, 2008; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/cae.20126

O B O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O


Lip segmentation and tracking under MAP-MRF framework with unknown segment number This paper proposes a color lip segmentation method with unknown true segment number. Firstly, we build up a multi-layer hierarchical model, in which each layer corresponds to one segment cluster. Subsequently, a Markov random field derived from this model is obtained such that the segmentation problem is formulated as a labeling optimization problem under the maximum a posteriori Markov random field (MAP-MRF) framework. Suppose the pre-assigned number of segment clusters may over-estimate the ground truth, whereby leading to the over-segmentation. We present a rival penalized iterative algorithm capable of performing segment clusters and over-segmentation elimination simultaneously. Based upon this algorithm, we propose a lip segmentation and tracking scheme, featuring the robust performance to the estimate of the number of segment clusters. Experimental results show the efficacy of the proposed method in comparison with the existing counterparts.

O O O O O O O O O B I O O O O B I I O O O O B I O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

color lip segmentation
hierarchical model
segment number


Quantifying the accuracy of the ground truth associated with Internet traffic traces Ground truth information for Internet traffic traces is often derived by means of port analysis and payload inspection (Deep Packet Inspection DPI). In this paper we analyze the errors that DPI and port analysis commit when assigning protocol labels to traffic traces. We compare the ground truth provided by these approaches with that derived by gt, a tool that we developed, which provides error-free ground truth at the application level by construction. Experimental results demonstrate that, depending on the protocols composing a trace, ground truth information from port analysis and DPI can be incorrect for up to 91% and 26% of the labeled bytes, respectively.

O O O O O O O O O B B O O O O O B B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Super-resolution image reconstruction for a steerable array of sub-imagers Super-resolution image reconstruction has many different application areas. A thin flat-form factor camera can use arrays of small low-resolution imagers with dynamic control of the overlapping fields-of-view to theoretically achieve arbitrarily fine resolution in some parts of a reconstructed image in a noise-free environment. Diversity in the structure of the sub-imagers has been shown to improve performance in medium and low noise environments and also to allow local reconstruction which lowers computational requirements. Analysis in both the space domain and spatial frequency domain of the relationship of measurement noise level and resolution improvement factor on performance explains the behavior of systems with diverse magnification and orientation. Simulations show expected performance over a range of relevant noise levels, and image examples are used to demonstrate results.

O B I O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

super-resolution
optimal estimation
flat camera design


infopipes for composing distributed information flows Building applications that process information flows on existing middleware platforms is difficult, because of the variety of QoS requirements, the need for application-specific protocols, and the poor match of the commonly used abstraction of remote invocations to streaming. We propose Infopipes as a high-level abstraction for building blocks that handle information flows. The ability to query individual Infopipe elements as well as composite Infopipes for properties of supported flows enables QoS-aware configuration. Similarly to local protocol frameworks Infopipes provide a flexible infrastructure for configuring communication services from modules, but unlike protocols the abstraction uniformly includes the entire pipeline from source to sink, possibly across process and node boundaries.

B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

distributed setup
quality of service
information flow
smart proxies