A cerebellar associative memory approach to option pricing and arbitrage trading Option pricing is a process to obtain the theoretical fair value of an option based on the factors affecting its price. The classical approaches to option pricing include the BlackScholes pricing formula and the binomial pricing model. These techniques, however, employ complex and rigid statistical formulations that are not easily comprehensible to novice investors. More recently, non-parametric and computational methods of option valuation that are able to construct a model of the pricing formula from historical data have been proposed in the literature. However, most of these models functioned as black-boxes and may not be able to efficiently and accurately capture the complex market dynamics and characteristics of the option data. This paper proposes a novel brain-inspired cerebellar associative memory model for pricing American-style call options on British pound vs. US dollar currency futures. The proposed model, named PSECMAC, constitutes a local learning model that is inspired by the neurophysiological aspects of the human cerebellum. The PSECMAC-based option-pricing model is subsequently applied in a mis-priced option arbitrage trading system. Simulation results show an encouraging return on investment of 23.1% for some of the traded options.

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

option pricing
psecmac
cerebellum
associative memory


class discovery in gene expression data Recent studies (Alizadeh et al, [1]; Bittner et al,[5]; Golub et al, [11]) demonstrate the discovery of putative disease subtypes from gene expression data. The underlying computational problem is to partition the set of sample tissues into statistically meaningful classes. In this paper we present a novel approach to class discovery and develop automatic analysis methods. Our approach is based on statistically scoring candidate partitions according to the overabundance of genes that separate the different classes. Indeed, in biological datasets, an overabundance of genes separating known classes is typically observed. we measure overabundance against a stochastic null model. This allows for highlighting subtle, yet meaningful, partitions that are supported on a small subset of the genes. Using simulated annealing we explore the space of all possible partitions of the set of samples, seeking partitions with statistically significant overabundance of differentially expressed genes. We demonstrate the performance of our methods on synthetic data, where we recover planted partitions. Finally, we turn to tumor expression datasets, and show that we find several highly pronounced partitions.

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

partition
space
performance
data
simulated annealing
demonstrate
model
gene expression
paper
class

measurement
analysis method
method
computation
express
discoveries
subtype
sampling
exploration


Feature-based 3D morphing based on geometrically constrained spherical parameterization Current trends in free form editing motivate the development of a novel editing paradigm for CAD models beyond traditional CAD editing of mechanical parts. To this end, we need robust and efficient 3D mesh deformation techniques such as 3D structural morphing. In this paper, we present a feature-based approach to 3D morphing of arbitrary genus-0 polyhedral objects that is appropriate for CAD editing. The technique is based on a sphere parameterization process built on an optimization technique that uses a target function to maintain the correspondence between the initial polygons and the mapped ones, while preserving topology and connectivity through a system of geometric constraints. Finally, we introduce a fully automated feature-based technique that matches surface areas (feature regions) with similar topological characteristics between the two morphed objects and performs morphing according to this feature correspondence list. Alignment is obtained without user intervention based on pattern matching between the feature graphs of the two morphed objects. (C) 2011 Elsevier B.V. All rights reserved.

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

mesh parameterization
feature-based models
animation


Modeling and simulation for fatigue life analysis of robots with flexible joints under percussive impact forces A method is presented for modeling and analyzing the fatigue life of robots with flexible joints, with a particular focus on applications under percussive impact forces. A multiple-loading fatigue model is applied to determine the total number of the rivets that can be riveted before robot's fatigue failure. Based on simulation using our model, four observations are received and the fatigue life can be evaluated.

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


Mining Multidimensional and Multilevel Sequential Patterns Multidimensional databases have been designed to provide decision makers with the necessary tools to help them understand their data. This framework is different from transactional data as the datasets contain huge volumes of historicized and aggregated data defined over a set of dimensions that can be arranged through multiple levels of granularities. Many tools have been proposed to query the data and navigate through the levels of granularity. However, automatic tools are still missing to mine this type of data in order to discover regular specific patterns. In this article, we present a method for mining sequential patterns from multidimensional databases, at the same time taking advantage of the different dimensions and levels of granularity, which is original compared to existing work. The necessary definitions and algorithms are extended from regular sequential patterns to this particular case. Experiments are reported, showing the significance of this approach.

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

sequential patterns
multidimensional databases

frequent patterns
hierarchy
multilevel patterns


Improved differential evolution algorithms for solving generalized assignment problem DE is first designed to solve generalized assignment problem (GAP). The possibility of using new local search in DE for GAP is designed in order to get better solution. The computational results revealed that the proposed heuristic lies among the best algorithms found in the literature.

O O O O O O B I I 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

differential evolution algorithm
shifting procedure
exchange procedure


Biometrics in ambient intelligence The security concerns due to the September 11 and later terroristic attacks, fostered the development of more advanced techniques for biometric identification. This had a positive impact to research and deployment of these technologies, founding a basis for security-related applications. At the same time, the privacy concerns for the misuse of personal information have hindered the application of the same technologies wherever their introduction could not be enforced. The risk is for the scientific development to be blocked by contradictory needs, which, in turn, often derive from misconceptions or misunderstanding of the real potential of biometric technologies. Within this context, ambient intelligence allows to consider the relation between biometrics and privacy under a different perspective. In fact, as most of times we are able to maintain social relations without the need to know each others identity (consider for example the case of a customer relating with an attendant at a department store), in the same way biometric technologies can facilitate the manmachine interaction (to better provide useful services) without the need to determine the users full identity. Also in the case of security applications, most often may be sufficient to retrieve ancillary information about a subject rather than determining his/her identity. This paper analyzes the potential of biometric technologies within the general scope of ambient intelligence, trying to identify some key technological issues which may respond to privacy concerns. Some example applications are considered where by exploiting the information contained in biometric data, such as the facial expression or other, non visual, measurements, it is possible to better relate the user with the environment and provide a substantial input to drive the services provided, without compromising his privacy.

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 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

human machine interaction
pattern recognition
cognition
computer vision
robotics


efficient evaluation of high-selective xml twig patterns with parent child edges in tree-unaware rdbms Recent study showed that native twig join algorithms and tree-aware relational framework significantly outperform tree-unaware approaches in evaluating structural relationships in XML twig queries. In this paper, we present an efficient strategy to evaluate high-selective twig queries containing only parent-child relationships in a tree-unaware relational environment. Our scheme is built on top of our S UCXENT ++ system. We show that by exploiting the encoding scheme of S UCXENT ++, we can devise efficient strategy for evaluating such twig queries. Extensive performance studies on various data sets and queries show that our approach performs better than a representative tree-unaware approach (G LOBAL -O RDER ) and a state-of-the-art native twig join algorithm (TJF AST ) on all benchmark queries with the highest observed gain factors being 243 and 95, respectively. Additionally, our approach reduces significantly the performance gap between tree-aware and tree-unaware approaches and even outperforms a tree-aware approach(M ONET DB/XQ UERY ) for certain high-selective twig queries. We also report our insights to the plan choices a relational optimizer made during twig query evaluation by visually characterizing its behavior over the relational selectivity space.

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

xml
parent child edges
twig query evaluation


Nonlinear discriminant clustering based on spectral regularization Owing to sparseness, directly clustering high-dimensional data is still a challenge problem. Therefore, obtaining their low-dimensional compact representation by dimensional reduction is an effective method for clustering high-dimensional data. Most of existing dimensionality reduction methods, however, are developed originally for classification (such as Linear Discriminant Analysis) or recovering the geometric structure (known as manifold) of high-dimensional data (such as Locally Linear Embedding) rather than clustering purpose. Hence, a novel nonlinear discriminant clustering by dimensional reduction based on spectral regularization is proposed. The contributions of the proposed method are two folds: (1) it can obtain nonlinear low-dimensional representation that can recover the intrinsic manifold structure as well as enhance the cluster structure of the original high-dimensional data; (2) the clustering results can also be obtained in the dimensionality reduction procedure. Firstly, the desired low-dimensional coordinates are represented as linear combinations of predefined smooth vectors with respect to the data manifold, which are characterized by a weighted graph. Then, the optimal combination coefficients and the optimal cluster assignment matrix are computed by maximizing the ratio between the between-cluster scatter and the total scatter simultaneously as well as preserving the smoothness of the cluster assignment matrix with respect to the data manifold. Finally, the optimization problem is solved in an iterative procedure, which is proved to be convergent. Experiments on UCI data sets and real world data sets demonstrated the effectiveness of the proposed method for both clustering and visualization high-dimensional data set.

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 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 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 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

dimensionality reduction
spectral regularization
cluster structure


Applications of the operator H(?,?) H ( ? , ? ) to the Humbert double hypergeometric functions By making use of some techniques based upon certain new inverse pairs of symbolic operators, the authors investigate several decomposition formulas associated with Humbert hypergeometric functions ?1 ? 1 , ?2 ? 2 , ?3 ? 3 , ?1 ? 1 , ?2 ? 2 , ?1 ? 1 and ?2 ? 2 . These operational representations are constructed and applied in order to derive the corresponding decomposition formulas. With the help of these inverse pairs of symbolic operators, as many as 34 decomposition formulas are found. Euler type integrals connected with Humbert functions are also presented.

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

decomposition formulas
humbert hypergeometric functions
inverse pairs of symbolic operators

mellinbarnes contour integral representations


Analysis of wave gaits for energy efficiency In this paper an energy efficiency analysis of wave gaits is performed for a six-legged walking robot. A simulation model of the robot is used to obtain the data demonstrating the energy consumption while walking in different modes and with varying parameters. Based on the analysis of this data some strategies are derived in order to minimize the search effort for determining the parameters of the gaits for an energy efficient walk. Then, similar data is obtained from an actual experimental setup, in which the Robot-EA308 is used as the walking machine. The strategies are justified based on this realistic data. The analysis concludes the following: a phase modified version of wave gaits is more efficient than the (conventional) wave gaits, using the possible minimum protraction time results in more energy efficient gaits and higher velocity results in less energy consumption per traveled distance. A stability analysis is performed for the phase modification of the wave gaits, and the stability loss due to the modification is calculated. It is concluded that the loss in stability is insignificant.

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

wave gaits
walking
energy
efficiency
stability


Should remote collaborators be represented by avatars? A matter of common ground for collective medical decision-making In a collaborative work situation at a distance, the use of avatars to represent collaborators reduces collaborative effort. Also, animated avatars can help distant users to ground their relationship and facilitate their interaction because they materialise visual clues for the distant collaborators and their current activity. To check the validity of these hypotheses we set up an experiment based on the use of a collaborative virtual environment (CVE) synchronised for collective medical decision-making. Several teams of practitioners from different disciplines will be required to deal with liver tumours displayed in Argonaute 3D. In this paper, we provide some evidence from existing studies for the hypotheses and select several measures to estimate the grounding process in CVEs. Next, we briefly describe the setup used to collect observable data with Argonaute 3D and we summarise first observations acquired with practitioners.

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 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 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

collaborative virtual environment
avatars

mediated collaboration
conversational grounding
medical decision-making


Mesh massage - A versatile mesh optimization framework We present a general framework for post-processing and optimizing surface meshes with respect to various target criteria. On the one hand, the framework allows us to control the shapes of the mesh triangles by applying simple averaging operations; on the other hand we can control the Hausdorff distance to some reference geometry by minimizing a quadratic energy. Due to the simplicity of this setup, the framework is efficient and easy to implement, yet it also constitutes an effective and versatile tool with a variety of possible applications. In particular, we use it to reduce the texture distortion in animated mesh sequences, to improve the results of cross-parameterizations, and to minimize the distance between meshes and their remeshes.

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 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

laplacian smoothing
parameterization
remeshing


Observation-based missing data methods for exploratory data analysis to unveil the connection between observations and variables in latent subspace models This paper introduces a class of methods to infer the relationship between observations and variables in latent subspace models. The approach is a modification of the recently proposed missing data methods for exploratory data analysis (MEDA). MEDA is useful to identify the structure in the data and also to interpret the contribution of each latent variable. In this paper, MEDA is augmented with dummy variables to find the data variables related to a given deviation detected among observations, for instance, the difference between one cluster of observations and the bulk of the data. The MEDA extension, referred to as observation-based MEDA or oMEDA, can be performed in several ways, one of which is theoretically shown to be equivalent to a comparison of means between groups. The use of the proposed approach is demonstrated with a number of examples with simulated data and a real data set of archeological artifacts. Copyright (C) 2011 John Wiley & Sons, Ltd.

O B I 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 B I 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

data understanding
latent structures
biplots


A reduced basis element method for the steady Stokes problem: Application to hierarchical flow systems The reduced basis element method is a new approach for approximating the solution of problems described by partial differential equations. The method takes its roots in domain decomposition methods and reduced basis discretizations (Fink & Rheinboldt (1983), Noor & Peters (1980), Prud'homme et al. (2002)), and its applications extend to, for example, control and optimization problems. The basic idea is to first decompose the computational domain into a series of subdomains that are similar to a few reference domains (or generic computational parts). Associated with each reference domain are precomputed solutions corresponding to the same governing partial differential equation, but solved for different choices of some underlying parameter. In this work, the parameters are representing the geometric shape associated with a computational part. The approximation corresponding to a new shape is then taken to be a linear combination of the precomputed solutions, mapped from the reference domain for the part to the actual domain. We extend earlier work (Maday & Ronquist (2002), Maday & Ronquist (2004)) in this direction to solve incompressible fluid flow problems,governed by the steady Stokes equations. Particular focus is given to constructing the basis functions, to the mapping of the velocity fields, to satisfying the inf-sup condition, and to "gluing" the local solutions together in the multidomain case (Belgacem et al. (2000)). We also demonstrate an algorithm for choosing the most efficient precomputed solutions. Two-dimensional examples are presented for pipes, bifurcations, and couplings of pipes and bifurcations in order to simulate hierarchical flow systems.

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

stokes flow
reduced order model
mortar method
output bounds
a posteriori error estimators


traceability and completeness checking for agent-oriented systems In this paper, we describe a rule-based approach to support traceability and completeness checking of design models and code specification of agent-oriented systems. The rules are specified in an extension of XQuery and allow the generation of traceability relations and checking of completeness of artifacts represented in Prometheus design models and JACK code specification. An example of an Electronic Bookstore agent oriented system is used to illustrate the work.

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

multi-agent systems
agent oriented software engineering


A failure-to-safety robot system for human-robot coexistence In this paper, we discuss a method to achieve a failure-to-safety robot system. First, we point out that there has been little study on human detection through contact sensing and we establish the human pain tolerance for human-oriented design of a safe robot. Secondly, for reliability purposes, we provide a method of sensing contact force by monitoring the direct drive motor current and speed of the robot, without any external sensors. Thirdly, we propose a design method of covering a robot with a viscoelastic material to achieve both impact force attenuation and contact sensitivity, keeping within the human pain tolerance limit. Finally, we covered a two-link arm manipulator with an accordingly designed soft covering material, and demonstrated that the developed manipulator system gives no pain to humans.

O O O O O O O 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 B I 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 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

human detection
pain tolerance
contact sensing


learning a word processing system with training wheels and guided exploration A Training Wheels interface creates a reduced functionality system intended to prevent new users from suffering the consequences of certain types of common errors when they exercise system functions and procedures. This has been shown to be an effective training system design for learning basic text editing functions [4]. We extend this result by examining the extent to which training wheels learners can transfer their skills to interaction with the full-function system. The experiment reported here indicates that training wheels subjects were better able to perform advanced full-system editing functions than subjects who were trained on the full system itself.

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

interaction
training
system design
users
types
text
exercise
learning
errors
exploration

error blocking
systems
procedure
edit
functional
minimalist documentation
skill transfer
training wheels
process
user training
interfaces
experience
skill
effect
guided exploration


Bottom water formation in the Weddell Sea resolved by principal component analysis and target estimation The general mixing situation in the southern Weddell Sea is studied by principal components analysis (PCA). A method for computing the fractions of the assumed source waters in a given sample is presented. The method is applied to the formation of Antarctic Bottom Water in the southern part of the Weddell Sea. The algorithm is a combination of PCA and regression. The method can be used to compile the variation in a number of measured variables without limitations of the variable count. Previous oceanographic knowledge is combined with the score mixing patterns in order to estimate the number of source waters and their compositions. In the application described, the principle of this method is demonstrated with the variables temperature, salinity and oxygen. Three source waters were indicated by PCA and the fractions of the two source waters, ice shelf water and warm deep water were calculated. (C) 1998 Elsevier Science B.V. All rights reserved.

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

bottom water
weddell sea
target estimation


An analysis for AlGaN/GaN modulation doped field effect transistor using accurate velocity-field dependence for high power microwave frequency applications An analytical model of Al0.15Ga0.85N/GaN modulation doped field effect transistor (MODFET), which uses an accurate velocity field relationship and incorporates the dominant effect of piezoelectric polarization induced charge at the AlGaN/GaN interface is presented. The effect of traps has also been taken into account. The calculated DC characteristics are in excellent agreement with the measured data. The model is extended to predict the microwave performance of the device. High current levels (>500mA/mm), large transconductance (160.83mS/mm) and a high cutoff frequency (9.6GHz) have been achieved analytically and are in close agreement with the experimental data.

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

velocity field relationship
cutoff frequency


How big data serves for freight safety management at highway-rail grade crossings? A spatial approach fused with path analysis Future vehicle warning systems needs a local (instead of global) analysis of real-time information transmitted between vehicles and infrastructures, to provide local warning information matching the instantaneous driving contexts. Spatial modeling techniques extracting the location information into the analysis fulfill the needs of local analysis. For truck-involved collisions at highway-rail crossings, the local warnings seem to matters more, than for traffic crashes at the normal highway segments and regular intersections. Crashes at rail grade crossings can result in severe injuries and fatalities to vehicle occupants, while truck-involved crashes at crossings can further result in serious damage to train, crossing and railway equipment. Truck-involved crashes at grade crossings have received limited attention compared with crashes involved with passenger cars. This study presents a methodology of improving safety of trucks at railroad crossings, by taking advantage of the big data containing location information. Unlike previous studies that constructed a direct relationship between the safety outcomes and associated factors, this study investigates direct relationships together with indirect relationships through the truck driver behaviors before collisions, using path analysis techniques. To sum up, this study applies a spatial approach fused with path analysis to uncover the local relationships between truck driver injury severity and crossing controls across the space. By doing so, the research is able to: i) provide a benchmark of identifying potentially risky vehicles on a real time basis; ii) evaluate current control devices at railroad crossing across the country and pin point the potentially problematic crossing sites. An empirical study was conducted by using a rich crash database from the Federal Railroad Administration (N= 4738 for 20042014). The results show that truck-involved crashes occurring at crossings without gate controls are generally associated with higher chance of injury, while the associations vary significantly across the space. In general, crashes in the Midwest and Great Lake regions are associated with an even higher chance of injury at crossings without gates, compared with other regions. More Results and implications are discussed in the paper.

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

highway-rail grade crossing
truck crash
driving behavior
geographically
weighted regressionpath analysis


Look-ahead dynamic threshold voltage control scheme for improving write margin of SOI-7T-SRAM Instability of SRAM memory cells derived from aggressive technology scaling has been recently one of the most significant issues. Although a 7T-SRAM cell with an area-tolerable separated read port improves read margins even at sub-1V, it unfortunately results in degradation of write margins. In order to assist the write operation, we address a new memory cell employing a look-ahead body-bias which dynamically controls the threshold voltage. Simulation results have shown improvement in both the write margins and access time without increasing the leakage power derived from the body-bias.

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


Models and Framework for Supporting Runtime Decisions in Web-Based Systems Efficient management of distributed Web-based systems requires several mechanisms that decide on request dispatching, load balance, admission control, request redirection. The algorithms behind these mechanisms typically make fast decisions on the basis of the load conditions of the system resources. The architecture complexity and workloads characterizing most Web-based services make it extremely difficult to deduce a representative view of a resource load from collected measures that show extreme variability even at different time scales. Hence, any decision based on instantaneous or average views of the system load may lead to useless or even wrong actions. As an alternative, we propose a two-phase strategy that first aims to obtain a representative view of the load trend from measured system values and then applies this representation to support runtime decision systems. We consider two classical problems behind decisions: how to detect significant and nontransient load changes of a system resource and how to predict its future load behavior. The two-phase strategy is based on stochastic functions that are characterized by a computational complexity that is compatible with runtime decisions. We describe, test, and tune the two-phase strategy by considering as a first example a multitier Web-based system that is subject to different classes of realistic and synthetic workloads. Also, we integrate the proposed strategy into a framework that we validate by applying it to support runtime decisions in a cluster Web system and in a locally distributed Network Intrusion Detection System.

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

design
measurement
performance
world wide web
load prediction
load change detection
distributed systems
load representation


Utilizing Wiki-Systems in higher education classes: a chance for universal access? Wikis are a website technology for mass collaborative authoring. Today, wikis are increasingly used for educational purposes. Basically, the most important asset of wikis is free and easy access for end users: everybody can contribute, comment and editfollowing the principles of Universal access. Consequently, wikis are ideally suited for collaborative learning and a number of studies reported a great success of wikis in terms of active participation, collaboration, and a rapidly growing content. However, the wikis success in education was often linked either to direct incentives or even pressure. This paper strongly argues that this contradicts the original intentions of wikis and, furthermore, weakens the psycho-pedagogical impact. A study is presented which focuses on investigating the success of wikis in higher education, when students are neither enforced to contribute nor directly rewarded similar to the principles of Wikipedia. Amazingly, the results show that, in total, none of the N=287 students created new articles or edited existing ones during a whole semester. It is concluded that the use of Wiki-Systems in educational settings is much more complicated, and it needs more time to develop a kind of give-and-take generation.

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 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 B I 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

wikipedia
higher education
collaborative learning

technology enhanced learning
wiki
civil engineering


Parallel solutions of simple indexed recurrence equations We define a new type of recurrence equations called "Simple Indexed Recurrences" (SIR). In this type of equations. ordinary recurrences are generalized to X[g(i)] = op(i) (X[f(i)],X[g(i)]), where f,g : {1... n}bar right arrow{1...m}, op(i)(x, y) is a binary associative operator and g is distinct. i.e., For All (i) not equal j g(i) not equal g(j). This enables us to model certain sequential loops as a sequence of SIR equations. A parallel algorithm that solves a set of SIR equations will, in fact, parallelize sequential loops of the above type. Such a parallel SIR algorithm must be efficient enough to compete with the O(n) work complexity of the original loop. We show why efficient parallel algorithms for the related problems of List Ranking and Tree Contraction. which require O(n.) work, cannot be applied to solving SIR. We instead use repeated iterations of pointer jumping to compute the final values of X[] in n/p . log p steps and n . logp work, with I, processors. A sequence of experiments was performed to test the effect of synchronous and asynchronous executions on the actual performance of the algorithm. These experiments show that pointer jumping requires O(n) work in most practical cases of SIR loops. An efficient solution is given for the special case where we know how to compute the inverse of op(i), and finally, useful applications of SIR to the well-known Livermore Loops benchmark are presented.

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

indexed recurrence equations
pointer jumping
list ranking
tree contraction
livermore loops benchmark

ordinary recurrence equations
parallel prefix sums
euler tour
parallelizing compilers


Rate distortion optimization for H.264 interframe coding: A general framework and algorithms Rate distortion (RD) optimization for H.264 inter-frame coding with complete baseline decoding compatibility is investigated on a frame basis. Using soft decision quantization (SDQ) rather than the standard hard decision quantization, we first establish a general framework in which motion estimation, quantization, and entropy coding (in H.264) for the current frame can be jointly designed to minimize a true RD cost given previously coded reference frames. We then propose three RD optimization algorithms-a graph-based algorithm for near optimal SDQ in H.264 baseline encoding given motion estimation and quantization step sizes, an algorithm for near optimal residual coding in H.264 baseline encoding given motion estimation, and an iterative overall algorithm to optimize H.264 baseline encoding for each individual frame given previously coded reference frames-with them embedded in the indicated order. The graph-based algorithm for near optimal SDQ is the core; given motion estimation and quantization step sizes, it is guaranteed to perform optimal SDQ if the weak adjacent block dependency utilized in the context adaptive variable length coding of H.264 is ignored for optimization. The proposed algorithms have been implemented based on the reference encoder JM82 of H.264 with complete compatibility to the baseline profile. Experiments show that for a set of typical video testing sequences, the graph-based algorithm for near optimal SDQ, the algorithm for near optimal residual coding, and the overall algorithm achieve on average, 6%, 8%, and 12%, respectively, rate reduction at the same PSNR (ranging from 30 to 38 dB) when compared with the RD optimization method implemented in the H.264 reference software.

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

fixed-slope lossy compression
h.264 hybrid coding
rate distortion (rd) optimization
soft decision quantization (sdq)


Reconstructing Open Surfaces via Graph-Cuts A novel graph-cuts-based method is proposed for reconstructing open surfaces from unordered point sets. Through a Boolean operation on the crust around the data set, the open surface problem is translated to a watertight surface problem within a restricted region. Integrating the variational model, Delaunay-based tetrahedral mesh and multiphase technique, the proposed method can reconstruct open surfaces robustly and effectively. Furthermore, a surface reconstruction method with domain decomposition is presented, which is based on the new open surface reconstruction method. This method can handle more general surfaces, such as nonorientable surfaces. The algorithm is designed in a parallel-friendly way and necessary measures are taken to eliminate cracks and conflicts between the subdomains. Numerical examples are included to demonstrate the robustness and effectiveness of the proposed method on watertight, open orientable, open nonorientable surfaces and combinations of such.

O O O O O O O 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 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


Exploiting cross-coupled and body-driven techniques for noise cancellation of an inductor-less wideband LNA In this paper, using bulk terminal of transistors as well as auxiliary cross-coupled amplifiers, the gain and noise figure (NF) of a conventional common-source low-noise amplifier (LNA) with resistive feedback are improved significantly. The proposed LNA utilizes a new technique for cancelling the thermal noise of transistors. This LNA is simulated in a 0.18?m CMOS technology. Simulation results show a 28-dB voltage gain for the frequency range of 101000MHz, and IIP3 better than ?11dBm. The noise figure in the frequency range of 1001000MHz is 1.21.4dB. Moreover; the noise figure in the frequency range of 35100MHz is also less than 2dB. The total current drawn from a 1.8-V supply voltage is 15mA.

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

cross-coupled
noise figure (nf)
low-noise amplifier (lna)


Global optimization for special reverse convex programming A global optimization algorithm is proposed in order to locate the global minimum of the special reverse convex programming which is both nonconvex and nonlinear. Three new strategies are adopted in this paper. Some of them can be used to solve general reverse convex programming. Global solution locating is to identify the location of the solution. The linear relaxation method is used to obtain the lower bound of the optimum of the primal programming, and in this paper the relaxed programming is a kind of linear programming, which can be solved by standard simplex algorithm. The final strategy is upper bound updating method, which provides a better upper bound than the standard branch and bound method. According to the strategies, a global optimization algorithm is derived based on branch and bound theory. It is proved that the algorithm possesses global convergence. Finally, a numerical experiment is given to illustrate the feasibility and the smaller computational effort.

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

global optimization
reverse convex programming
branch and bound


Theoretical cryptanalysis of the Klimov-Shamir number generator TF-1 The internal state of the Klimov-Shamir number generator TF-1 consists of four words of size w bits each, whereas its intended strength is 2(2w). We exploit an asymmetry in its output function to show that the internal state can be recovered after having 2(w) outputs, using 2(1.5w) operations. For w = 32 the attack is practical, but for their recommended w = 64 it is only of theoretical interest.

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

pseudorandom number generators
t-functions
tf-1


predictable programs in barcodes We explore the challenges for making the programming interfaces for embedded devices open and safe, and present a prototype architecture for delivering verified programs using barcodes. In particular, we consider programs for microwave ovens, which provide a basic open API for controlling cooking times. In our architecture, recipes are written in Java, and their safety properties are formally verified using the model checker Spin. We use off-the-shelf utilities for compressing the byte code, and use two-dimensional barcodes for program delivery. We report on experiments that demonstrate the feasibility of the proposed architecture for predictability and delivery.

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

programmability of embedded devices
active barcodes
code delivery
formal verification


Large deformation FE analysis of driven steel pipe piles with soil plugging This paper presents the application of the Coupled EulerianLagrangian (CEL) numerical technique to simulate the driving of open-ended piles into sandy soil. The main objective of this study was to investigate the effect of soil plugging on the response of piles embedded in a single layer and in multiple layers. Comprehensive studies to verify the plugging effect are presented in this paper. Through comparison with results of field load tests, the CEL methodology was found to be in good agreement with the general trend observed by in situ measurement, and the CEL approach accurately simulated the behavior of the inner and outer skin friction from the radial stress. Additionally, a parametric study was performed by controlling the pile diameter, driving energy, elastic moduli of the soil and bearing layers, and length of pile embedded in the bearing layer. It was found that the soil plugging index (SPI) and maximum radial stress increased linearly with increasing driving energy and elastic moduli of soil and bearing layers, whereas the pile diameter and the length of pile embedded in the bearing layer were inversely proportional to the SPI. From the parametric studies, it was found that the largest influence was due to the effect of the driving energy, followed by the pile diameter, the length of pile embedded in the bearing layer, the soil elastic modulus, and the elastic modulus of the bearing layer.

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

large deformation fe analysis
plugging effect
radial stress
soil plugging index

coupled eulerianlagrangian method
open-ended piles


Minimizing a nonlinear function under a fuzzy max-t-norm relational equation constraint This work studies a nonlinear optimization problem subject to fuzzy relational equations with max-t-norm composition. Since the feasible domain of fuzzy relational equations with more than one minimal solution is non-convex, traditional nonlinear programming methods usually cannot solve them efficiently. This work proposes a genetic algorithm to solve this problem. This algorithm first locates the feasible domain through the maximum solution and the minimal solutions of the fuzzy relational equations, to significantly reduce the search space. The algorithm then executes all genetic operations inside this feasible domain, and thus avoids the need to check the feasibility of each solution generated. Moreover, it uses a local search operation to fine-tune each mutated solution. Experimental results indicate that the proposed algorithm can accelerate the searching speed and find the optimal solution.

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 B I I 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 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

fuzzy relational equations
genetic algorithm


Agile numerical modelling of real electric power plants A novel framework for numerical modelling of electric power plants is presented. Filter algorithms generate state-space models from instrument measurements. The numerical models are agile to adapt between different operational regimes. Original research conducted to a real electric power generation facility. The presented results were validated on site by the power plants chief engineers.

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

electric power plants
numerical modelling
filter algorithms


VE dimension induced by Bayesian networks over the boolean domain In this paper, we focus on the concept classes \({\mathcal {C}}_{{\mathcal{N}}}\) induced by Bayesian networks. The relationship between two-dimensional values induced by these concept classes is studied, one of which is the VC-dimension of the concept class \({\mathcal {C}}_{\cal {N}},\) denoted as \(VCdim({\mathcal {N}}), \) and other is the smallest dimensional of Euclidean spaces into which \({\mathcal {C}}_{{\mathcal {N}}}\) can be embedded, denoted as \(Edim({\mathcal {N}}). \) As a main result, we show that the two-dimensional values are equal for the Bayesian networks with n?4 variables, called the VE-dimension for that Bayesian networks.

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

classification
vc-dimension
inner product space


An approximation algorithm for box abstraction of transition systems on real state spaces Predicate abstraction is a powerful technique for extracting finite-state models from infinite-state systems such as computer software, and is applied to verification of safety properties. Predicate abstraction is also applied to verification of dynamical systems on real state spaces such as hybrid dynamical systems. In this paper, we propose a fast algorithm for computing entire abstract state spaces of transition systems on real state spaces. The method is based on the box abstraction of state spaces, and requires a relatively smaller number of reachability checks and Boolean operations. We also propose a fast method for computing the set of boxes that intersect a given convex polyhedron. This computation is a part of the proposed state-space generation algorithm. Effectiveness of the algorithm is evaluated by the computation time and by the difference of the approximated state space from the exact state space.

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

hybrid dynamical systems
predicate abstraction


optimal multi-objective design of power system damping controller using synergy of bacterial forging and particle swarm optimization In order to solve the parameter optimization problem of traditional power system stabilizer, a novel power system stabilizer (PSS) design method is proposed based on synergy of bacterial forging and particle swarm optimization algorithm. Bacterial foraging algorithm may lead to delay in reaching global solution. Particle swarm optimization may lead to entrapment in local minimum solution and obtain imprecise search results. The new algorithm is proposed to combines both algorithms' advantages in order to get better optimization values. A coordinate optimization index based on multi-object and multiple operation conditions is presented so as to improve the damping ratios of electromechanical modes and increase the robustness of power system. In this paper, PSS design for single machine infinite bus is formulated as multi-objective and multi-operating conditions, and the hybrid approach involving bacterial foraging and particle swarm optimization algorithm is employed to solve this problem. The results of both eigenvalue analysis and nonlinear simulation show that the proposed PSS can damp the low-frequency oscillations effectively and work well with high control performance under different operating conditions. Compared with PSS which is design by genetic algorithm, the proposed PSS in this paper has better damping characteristics.

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

damping controller
particle swarm
bacterial foraging


fast fully dynamic landmark-based estimation of shortest path distances in very large graphs Computing the shortest path between a pair of vertices in a graph is a fundamental primitive in graph algorithmics. Classical exact methods for this problem do not scale up to contemporary, rapidly evolving social networks with hundreds of millions of users and billions of connections. A number of approximate methods have been proposed, including several landmark-based methods that have been shown to scale up to very large graphs with acceptable accuracy. This paper presents two improvements to existing landmark-based shortest path estimation methods. The first improvement relates to the use of shortest-path trees (SPTs). Together with appropriate short-cutting heuristics, the use of SPTs allows to achieve higher accuracy with acceptable time and memory overhead. Furthermore, SPTs can be maintained incrementally under edge insertions and deletions, which allows for a fully-dynamic algorithm. The second improvement is a new landmark selection strategy that seeks to maximize the coverage of all shortest paths by the selected landmarks. The improved method is evaluated on the DBLP, Orkut, Twitter and Skype social 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 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 O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O 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 B O O O O O O O O O O O O B I

trees
shortest paths
landmarks
social networks


Bias-corrected realized variance under dependent microstructure noise The aim of this study is to develop a bias-correction method for realized variance (RV) estimation, where the equilibrium price process is contaminated with market microstructure noise, such as bid ask bounces and price-change discreteness. Although RV constitutes the simplest estimator of daily integrated variance, it remains strongly biased, and many estimators proposed in previous studies require prior knowledge about the dependence structure of microstructure noise to ensure unbiasedness and consistency. The dependence structure is unknown however, and needs to be estimated. A bias-correction method based on statistical inference from the general noise dependence structure is thus proposed. The results of Monte Carlo simulation indicate that the new approach is robust with respect to changes in the dependence of microstructure noise. (c) 2010 IMACS. Published by Elsevier B.V. All rights reserved.

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

realized variance
dependent microstructure noise


A Closed-Form MGF Expression of Instantaneous SNR for Weibull Fading Channels In this paper, a closed-form expression for the moment generating function (MGF) of the instantaneous signal to noise ratio (SNR) per symbol is derived for Weibull fading channels. The derived MGF is valid for the rational values of fading parameter and it is shown to be useful for analyzing the symbol error rate for the case of M-ary phase shift keying and M-ary quadrature amplitude modulation schemes. Also, the outage probability can be accurately evaluated by using the probability density function of instantaneous SNR considered in this work.

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

moment generating function
outage probability
weibull fading channels


A level set characteristic Galerkin finite element method for free surface flows This paper presents a numerical method for free surface flows that couples the incompressible Navier-Stokes equations with the level set method in the finite element framework. The implicit characteristic-Galerkin approximation together with the fractional four-step algorithm is employed to discretize the governing equations. The schemes for solving the level set evolution and reinitialization equations are verified with several benchmark cases, including stationary circle, rotation of a slotted disk and stretching of a circular fluid element. The results are compared with those calculated from the level set finite volume method of Yue et al. (Int. J Numer. Methods Fluids 2003; 42:853-884), which employed the third-order essentially non-oscillatory (ENO) schemes for advection of the level set function in a generalized curvilinear coordinate system. The comparison indicates that the characteristic Galerkin approximation of the level set equations yields more accurate solutions. The second-order accuracy of the Navier-Stokes solver is confirmed by simulation of decay vortex. The coupled system of the Navier-Stokes and level set equations then is validated by solitary wave and broken dam problems. The simulation results are in excellent agreement with experimental data. Copyright (c) 2005 John Wiley & Sons, Ltd.

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

level set method
solitary wave
broken dam

characteristic galerkin method
unstructured mesh
free surface flow


Convergence and Parameter Choice for Monte-Carlo Simulations of Diffusion MRI This paper describes a general and flexible Monte-Carlo simulation framework for diffusing spins that generates realistic synthetic data for diffusion magnetic resonance imaging. Similar systems in the literature consider only simple substrates and their authors do not consider convergence and parameter optimization. We show how to run Monte-Carlo simulations within complex irregular substrates. We compare the results of the Monte-Carlo simulation to an analytical model of restricted diffusion to assess precision and accuracy of the generated results. We obtain an optimal combination of spins and updates for a given run time by trading off number of updates in favor of number of spins such that precision and accuracy of sythesized data are both optimized. Further experiments demonstrate the system using a tissue environment that current analytic models cannot capture. This tissue model incorporates swelling, abutting, and deformation. Swelling-induced restriction in the extracellular space due to the effects of abutting cylinders leads to large departures from the predictions of the analytical model, which does not capture these effects. This swelling-induced restriction may be an important mechanism in explaining the changes in apparent diffusion constant observed in the aftermath of acute ischemic stroke.

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

diffusion magnetic resonance imaging (mri)


Effective link interference model in topology control of wireless Ad hoc and sensor networks Topology control is an important way of reducing the link interference in wireless Ad hoc and sensor networks with shared channel. Modeling link interference is the primary step for designing interference-aware topology controls, and it is very critical to the efficacy of the topology control schemes in use. This paper presents a new link interference model, which can not only be easily calculated with global or local algorithms, but also more effectively profile the link interference in co-channel wireless Ad hoc and sensor networks than previous models. Based on the proposed model, a centralized topology control algorithm is designed to construct interference-optimal topologies. In fact, our model can also be fed into most of the already-existed topology control algorithms aimed at reducing link interferences. Finally, extensive simulations and analysis are conducted to evaluate our designs in detail. The simulation results show the outstanding effectiveness of interference reduction achieved by our model and algorithm, in comparison with the previous work.

O B I I 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 B I 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 B I 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

link interference model
topology control


Non-isothermal, non-Newtonian Hele-Shaw flows within Cattaneo's heat flux law In this paper, we consider a non-isothermal, non-Newtonian injection process. This leads to the study of a novel elliptic-hyperbolic system. The hyperbolic nature of the system arises because we replace the infinite speed of propagation from classical, thermal elasticity by a finite propagation velocity. We present a formal derivation of the elliptic-hyperbolic system starting from conservations of mass, momentum, and energy in a three-dimensional domain, where the removal of the infinite propagation speed is achieved using Cattaneo's law for heat conduction. The existence of weak solutions to certain elliptic-hyperbolic problems associated with the resulting equations is proved. (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 O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

hyperbolic heat equation
hele-shaw approximation
lubrication approximation


A CAT ALGORITHM FOR THE EXHAUSTIVE GENERATION OF ICE PILES We present a CAT (constant amortized time) algorithm for generating those partitions of n that are in the ice pile model IPM(k)(n), a generalization of the sand pile model SPM(n). More precisely, for any fixed integer k, we show that the negative lexicographic ordering naturally identifies a tree structure on the lattice IPM(k)(n): this lets us design an algorithm which generates all the ice piles of IPM(k)(n) in amortized time O(1) and in space O(root n).

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 B I I 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

sand pile model
ice pile model
exhaustive generation

integer partitions
cat algorithms
discrete dynamical systems


Solution of diffusion-dispersion models using a computationally efficient technique of orthogonal collocation on finite elements with cubic Hermite as basis In this paper, linear and non linear diffusion-dispersion models involving fluid flow through porous cylindrical particles are solved using orthogonal collocation on finite elements with cubic Hermite as basis. The technique involves partitioning of axial domain into equal elements and then orthogonal collocation method with cubic Hermite as basis function is applied within each element. Exit concentration profiles are drawn for Peclet numbers ranging from 0 (perfect mixing) to 8 (perfect displacement). Proposed technique is computationally efficient, stable and yields accurate solution, even for nonlinear stiff problem. Correlation with industrial parameters is also presented. (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 O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

langmuir isotherm
axial dispersion model
diffusion
cubic hermite basis
peclet number
exit solute concentration


Remote sensing image fusion via wavelet transform and sparse representation In this paper, we propose a remote sensing image fusion method which combines the wavelet transform and sparse representation to obtain fusion images with high spectral resolution and high spatial resolution. Firstly, intensity-hue-saturation (IHS) transform is applied to Multi-Spectral (MS) images. Then, wavelet transform is used to the intensity component of MS images and the Panchromatic (Pan) image to construct the multi-scale representation respectively. With the multi-scale representation, different fusion strategies are taken on the low-frequency and the high-frequency sub-images. Sparse representation with training dictionary is introduced into the low-frequency sub-image fusion. The fusion rule for the sparse representation coefficients of the low-frequency sub-images is defined by the spatial frequency maximum. For high-frequency sub-images with prolific detail information, the fusion rule is established by the images information fusion measurement indicator. Finally, the fused results are obtained through inverse wavelet transform and inverse IHS transform. The wavelet transform has the ability to extract the spectral information and the global spatial details from the original pairwise images, while sparse representation can extract the local structures of images effectively. Therefore, our proposed fusion method can well preserve the spectral information and the spatial detail information of the original images. The experimental results on the remote sensing images have demonstrated that our proposed method could well maintain the spectral characteristics of fusion images with a high spatial resolution.

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

remote sensing image fusion
wavelet transform
sparse representation
training dictionary


Automated recognition of stratigraphic marker shales from geophysical logs in iron ore deposits We apply Gaussian Processes to identify marker shales in iron ore mines. We examine manual and active learning methods of training Gaussian Processes. The active learning's use of uncertainty increases the accuracy of results. The active learning method can replace more than 3/4 of the manual interpretations.

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


Automatic Assessment of 3D Modeling Exams Computer-based assessment of exams provides teachers and students with two main benefits: fairness and effectiveness in the evaluation process. This paper proposes a fully automatic evaluation tool for the Graphic and Virtual Design (GVD) curriculum at the First School of Architecture of the Politecnico di Torino, Italy. In particular, the tool is designed for the 3D modeling course, taught during the second year, where students have to prove their ability to model static scenes using the open source modeler Blender. During the final exam, students are required to create a 3D model as similar as possible to a reference object proposed by the teacher and shown through a set of 2D views; the similarity of the images is judged according to both model shape and materials. The traditional assessment process is particularly slow and strongly based on teachers subjective evaluation; the proposed solution efficiently implements an objective assessment mechanism that exploits computer vision and image analysis algorithms to automatically extract similarity indices. These indices are related to partial evaluation grades, which are then combined to obtain the final mark. A comparison with the traditional assessment process shows robustness and trustworthiness of the designed approach.

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 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

evaluation methodologies
teaching and learning strategies
higher education
computer graphics


The heuristic, GLRT, and MAP detectors for double differential modulation are identical We consider the relationship between several single-symbol detectors for double differential modulation. We have shown in a previous paper that a simple heuristic detector is identical to the generalized likelihood ratio test (GLRT) detector. In this correspondence, we introduce a maximum a posteriori probability (MAP) detector and show that it is identical to the heuristic and GLRT detectors. Consequently, neither GLRT nor MAP can offer any gain over the simple heuristic detector, which means that the latter should be the detector of choice.

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

generalized likelihood ratio test (glrt)

maximum a posteriori probability (map) detector

single and double differential modulation


Digital-carrier multi-band user codes for baseband UWB multiple access The growing interest towards ultra-wideband (UWB) communications stems from its unique features such as baseband operation, ample multipath diversity, and the potential of enhanced user capacity. But since UWB has to overlay existing narrowband systems, multiple access has to be achieved in the presence of narrowband interference (NBI). However, existing baseband spreading codes for UWB multiple access are not flexible in handling NBI. In this paper, we introduce two novel spreading codes that not only enable baseband UWB multiple access, but also facilitate flexible NBI cancellation. We construct our codes using a single carrier or multiple carriers (SC or MC), which can be implemented with standard discrete-cosine transform (DCT) circuits. With our SC/MC codes, NBI can be avoided by simply nulling undesired digital carriers. Being digital, these SC/MC codes give rise to multiband UWB systems, without invoking analog carriers. In addition, our SC/MC codes enable full multipath diversity, and maximum coding gains. Equally attractive is their capability to reduce the number of interfering users, with simple matched filter operations. Comprehensive simulations are also carried out to corroborate our analysis.

O O 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 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

ultra-wideband (uwb)
diversity gain
coding gain
rake
direct-sequence (ds)
single-carrier (sc)
multicarrier (mc)
narrowband interference (nbi)
multi-user interference (mui)
discrete cosine transform (dct)


A comparison of extrinsic clustering evaluation metrics based on formal constraints There is a wide set of evaluation metrics available to compare the quality of text clustering algorithms. In this article, we define a few intuitive formal constraints on such metrics which shed light on which aspects of the quality of a clustering are captured by different metric families. These formal constraints are validated in an experiment involving human assessments, and compared with other constraints proposed in the literature. Our analysis of a wide range of metrics shows that only BCubed satisfies all formal constraints. We also extend the analysis to the problem of overlapping clustering, where items can simultaneously belong to more than one cluster. As Bcubed cannot be directly applied to this task, we propose a modified version of Bcubed that avoids the problems found with other metrics.

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

clustering
evaluation metrics
formal constraints


a micro-ethical view on computing practice Critical computing should include a concern for the everyday work practice of IT professionals. We explain our 'micro-ethical view', which shifts focus towards everyday work culture, seemingly mundane action, and describe what is gained thereby and by 'preventive' ethics. Four scenarios illustrate the situations relevant for our analysis. Reconstructing the history of 'responsibility' uncovers various concepts that provide fields of tension and systematize our analysis. We finish with related research questions relevant for this micro-ethical view that offer a broad field for research, as well as for professional action.

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 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 O O O O O O

responsibility
everyday work practice
ethics
work culture

professional practice
moral improvisation
self-reflection


Simple equations on binary factorial languages We consider equations on the monoid of factorial languages on the binary alphabet. We use the notion of a canonical decomposition of a factorial language and previous results by Avgustinovich and the author to solve several simple equations on binary factorial languages including X(n) = Y(n), the commutation equation XY = YX and the conjugacy equation XZ = ZY. At the end of the paper, we discuss the difficulties hindering the reduction of equations on factorial languages to equations on words and the extension of the alphabet considered. (C) 2009 Elsevier B.V. All rights reserved.

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 B 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

commutation
conjugacy
monoid of factorial languages

language equations
catenation of languages
canonical decompositions


Inverse Lax-Wendroff procedure for numerical boundary conditions of conservation laws We develop a high order finite difference numerical boundary condition for solving hyperbolic conservation laws on a Cartesian mesh. The challenge results from the wide stencil of the interior high order scheme and the fact that the boundary intersects the grids in an arbitrary fashion. Our method is based on an inverse Lax-Wendroff procedure for the inflow boundary conditions. We repeatedly use the partial differential equation to write the normal derivatives to the inflow boundary in terms of the time derivatives and the tangential derivatives. With these normal derivatives, we can then impose accurate values of ghost points near the boundary by a Taylor expansion. At outflow boundaries, we use Lagrange extrapolation or least squares extrapolation if the solution is smooth, or a weighted essentially non-oscillatory (WENO) type extrapolation if a shock is close to the boundary. Extensive numerical examples are provided to illustrate that our method is high order accurate and has good performance when applied to one and two-dimensional scalar or system cases with the physical boundary not aligned with the grids and with various boundary conditions including the solid wall boundary condition. Additional numerical cost due to our boundary treatment is discussed in some of the examples. (C) 2010 Elsevier Inc. All rights reserved.

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

numerical boundary conditions
hyperbolic conservation laws
cartesian mesh
extrapolation
solid wall

finite difference method
lax-wendroff procedure


A Griesmer bound for linear codes over finite quasi-Frobenius rings In this article we give a Griesmer type bound for linear codes over finite quasi-Frobenius rings and consider linear codes over these rings meeting the bound. And we study a geometrical characterization of linear codes over finite chain rings meeting the bound, that is, a one-to-one correspondence between these codes and minihypers in projective Hjelmslev spaces over these rings.

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

codes over rings
quasi-frobenius rings
projective hjelmslev geometries


eigentransport for efficient and accurate all-frequency relighting We present a method for creating a geometry-dependent basis for diffuse precomputed radiance transfer. Unlike previous PRT bases, ours is derived from Principal Component Analysis of the sampled transport functions at each vertex, without relying on pre-projections to secondary bases, such as the Spherical Harmonics or Haar wavelets. It allows for efficient evaluation of shading, has low memory requirements and produces accurate results with few coefficients. We are able to capture all-frequency effects from both distant and near-field dynamic lighting in real-time and present a simple and efficient rotation scheme. Reconstruction of the final shading becomes a low-order dot product and is performed on the GPU.

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

shading error analysis
realistic image synthesis
dimensionality reduction


Secure and Efficient Tree-based Group Diffie-Hellman Protocol Current group key agreement protocols (often tree-based) involve unnecessary delays because members with low-performance computer systems can join group key computation. These delays are caused by the computations needed to balance a key tree after membership changes. An alternate approach to group key generation that reduces delays is the dynamic prioritizing mechanism of filtering low performance members in group key generation. This paper presents an efficient tree-based group key agreement protocol and the results of its performance evaluation. The proposed approach to filtering of low performance members in group key generation is scalable and it requires less computational overhead than conventional tree-based protocols.

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 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

group key management
secure group communication


Monitoring of Linearly Accumulated Optical Impairments in All-Optical Networks Optical performance monitoring covers a very wide range of measurements intended to help ensure network performance and is essential for service providers. We address the problem of solving the linearly accumulated end-to-end impairments of a special set of paths of interest in a reconfigurable all-optical network. This set of paths of interest may include all the paths between any two communicating nodes. The main focus is on the minimization of the number of monitoring devices that are required. A set of channels is injected into the network and monitored. By using the correlation in the channel quality between injected channels, a framework of algebraic performance monitoring is proposed to derive the channel quality of the paths of interest from the linear combination of the monitoring results of the injected channel. The upper bounds on the minimum number of monitoring devices required are derived and constructively achieved for a general network. For a special network in which all nodes are capable of initiating and dropping the monitoring channels, the fundamental limit on the minimum number of monitoring devices is also achieved. The proposed monitoring scheme for this kind of network can also locate at least one fault, even if multiple faults occur. We reduce the cost of monitoring by utilizing the information from the monitoring results and minimizing the number of monitoring devices.

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

all-optical networks
fiber optics communications
optical communications


A re-configurable multi-agent system architecture for error recovery in production systems Multi-agent systems for manufacturing systems appear to provide adequate response to abrupt disturbances on the shop floor. To date, most of the work has been focused on planning and scheduling but very little work has been done on issues pertaining to monitoring, diagnostics and error recovery. Our approach addresses the issue of combining the discipline of hierarchical systems with the agility of multi-agent systems. Within the context of a hierarchy, the focus is on the workstation level and, in particular, the construction of a re-configurable system having production agents, error recovery agents, and a mediator agent structure connecting production and recovery agent hierarchies. In addition, the relationship to a multi-level, multi-layer hierarchy control is established. This latter hierarchy, based on Petri Net constructs, serves, in one sense, as a retrieval based resource for process planning and generation of recovery plans for production and recovery agents within the proposed multi-agent system. An objective of this effort is to provide a test-bed for comparison of hierarchical systems, heterarchical, and a hybrid combination which is the focus of the investigation presented here.

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 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 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

multi-agent systems
hierarchical control
petri nets
flexible manufacturing systems


Spectral embedding of graphs In this paper we explore how to embed symbolic relational graphs with unweighted edges in a pattern-space. We adopt a graph-spectral approach. We use the leading eigenvectors of the graph adjacency matrix to define eigenmodes of the adjacency matrix. For each eigenmode, we compute vectors of spectral properties. These include the eigenmode perimeter, eigenmode volume, Cheeger number, inter-mode adjacency matrices and intermode edge-distance. We embed these vectors in a pattern-space using two contrasting approaches. The first of these involves performing principal or independent components analysis on the covariance matrix for the spectral pattern vectors. The second approach involves performing multidimensional scaling on the L2 norm for pairs of pattern vectors. We illustrate the utility of the embedding methods on neighbourhood graphs representing the arrangement of corner features in 2D images of 3D polyhedral objects. Two problems are investigated. The first of these is the clustering of graphs representing distinct objects viewed from different directions. The second is the identification of characteristic views of single objects. These two studies reveal that both embedding methods result in well-structured view spaces for graph-data extracted from 2D views of 3D objects.

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

graph spectra
graph clustering
view based recognition
principal component analysis
independent component analysis


ON THE EXISTENCE OF MINIMAL beta-POWERS If all proper factors of a word u are beta-power-free while u itself is not, then u is a minimal beta-power. We consider the following general problem: for which numbers k, beta, and p there exists a k-ary minimal beta-power of period p? For the case beta >= 2 we completely solve this problem. If the number beta = 9 these sets are almost exhaustive.

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

formal languages
power free words
minimal powers
circular words


Perceptual 3D rendering based on principles of analytical cubism ? Cubism, pioneered by Pablo Picasso and Georges Braque, was a breakthrough in art, influencing artists to abandon existing traditions. In this paper, we present a novel approach for cubist rendering of 3D synthetic environments. Rather than merely imitating cubist paintings, we apply the main principles of analytical cubism to 3D graphics rendering. In this respect, we develop a new cubist camera providing an extended view, and a perceptually based spatial imprecision technique that keeps the important regions of the scene within a certain area of the output. Additionally, several methods to provide a painterly style are applied. We demonstrate the effectiveness of our extending view method by comparing the visible face counts in the images rendered by the cubist camera model and the traditional perspective camera. Besides, we give an overall discussion of final results and apply user tests in which users compare our results very well with analytical cubist paintings but not synthetic cubist paintings.

O O O O O O O O B 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 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

non-photorealistic rendering
computer graphics


Optimal node-selection algorithm for parallel download in overlay content-distribution networks In this paper. we investigate the issue of server selection for parallel download in overlay content-distribution networks. To achieve high performance and resilience to failures, a receiver can make connections with multiple servers simultaneously and receive different portions of the data from the servers in parallel. Prior studies mostly focus on the user-centric performance objectives, such as reducing the round-trip time (RTT) or the completion time of individual download, but tend to ignore the congestion caused by the concurrent connections from different servers or the total network resource usage. The latter performance concerns are important for the service providers who operate content-distribution networks. In this paper, we present a node-selection scheme in a hypercube-like overlay network that generates the optimal server set with respect to the worst-case link stress (WLS) criterion. The algorithm allows scaling to a large system because it is very efficient and does not require network measurement or collection of topology or routing information. It has performance advantages in a number of areas, particularly against the random selection scheme. First, it minimizes the level of congestion at the bottleneck link. This is equivalent to maximizing the achievable throughput. Second, it consumes less network resources in terms of the total number of links used and the total bandwidth usage. Third, it often leads to low average round-trip time to selected servers, hence, allowing nearby nodes to exchange more data, an objective sought by many content-distribution systems. (C) 2009 Elsevier B.V. All rights reserved.

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

server selection
parallel download
link stress

node selection
overlay networks
hypercube
content-distribution networks
peer-to-peer networks


on designing an automated malaysian stemmer for the malay language (poster session) Online and interactive information retrieval systems are likely to play an increasing role in the Malay Language community. To facilitate and automate the process of matching morphological term variants, a stemmer focusing on common affix removal algorithms is proposed as part of the design of an information retrieval system for the Malay Language. Stemming is a morphological process of normalizing word tokens down to their essential roots. The proposed stemmer strips prefixes and suffixes off the word. The experiment conducted with web sites selected from the World Wide Web has exhibited substantial improvements in the number of words indexed.

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

information retrieval
world wide web
malay language
stemming


High quality navigation in computer games Navigation plays an important role in many modern computer games. Currently the motion of entities is often planned using a combination of scripting, grid-search methods, local reactive methods and flocking. In this paper we describe a novel approach, based on a technique originating from robotics, that computes a roadmap of smooth, collision-free navigation paths. Because the vast amount of computation time is spent in the pre-processing phase, navigation during the execution of an application is almost instantaneous. The created roadmap can be queried to obtain high quality paths. Furthermore, the applications of the roadmap are not limited to navigating an entity. Therefore, besides navigation for an entity, two other applications are presented; one for planning the motion of groups of entities and one for creating smooth camera movements through an environment. All applications are based on the same underlying techniques. (c) 2007 Elsevier B.V. All rights reserved.

O O B O B I B 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 B 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 B 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 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

navigation
roadmap
groups
computer games


What is the value of Taxicab(6)? For almost 350 years it was known that 1729 is the smallest integer which can be expressed as the sum of two positive cubes in two different ways. Motivated by a famous story involving Hardy and Ramanujan, a class of numbers called Taxicab Numbers has been defined: Taxicab(k, j, n) is the smallest number which can be expressed as the sum of j kth powers in n different ways. So, Taxicab( 3, 2, 2) = 1729; Taxicab( 4, 2, 2) = 635318657. Computing Taxicab Numbers is challenging and interesting, both from mathematical and programming points of view. The exact value of Taxicab( 6) = Taxicab( 3, 2, 6) is not known; however, recent results announced by Rathbun [R2002] show that Taxicab( 6) is in the interval [ 1018, 24153319581254312065344]. In this note we show that with probability greater than 99%, Taxicab( 6) = 24153319581254312065344.

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

hardy-ramanujan number
taxicab number
sampling