Error analysis of a Galerkin method to solve the forward problem in MEG using the boundary element method Sources of brain activity, e.g. epileptic foci, can be localized with Magnetoencephalography (MEG) measurements by recording the magnetic field outside the head. For a successful surgery a very high localization accuracy is needed. The most often used conductor model in the source localization is an analytic sphere, which is not always adequate, and thus a realistically shaped conductor model is needed. In this paper we examine a Galerkin method with linear basis functions to solve the forward problem in MEG using the boundary element method. Its accuracy is compared to the collocation method with constant and linear basis functions. The accuracies are determined for a unit sphere for which analytic solutions are available. The Galerkin method gives a clear improvement in the accuracy of the forward problem especially for the tangential component of the magnetic field. At realistic MEG measurement distances from the brain the Galerkin method reaches a given accuracy with lower computational costs than the collocation methods starting from a few hundreds of unknowns. With larger meshes the difference for the Galerkin method increases significantly.

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

magnetoencephalography
boundary element method
forward problem
galerkin method
collocation method


Piezoelectric materials of (1?x)Pb(Zr0.53Ti0.47)O3xBi(Y0.7Fe0.3)O3 for energy-harvesting devices This paper proposes a composition for use in energy harvesting (EH) devices. A modified conventional method is used to synthesize the ceramics. All the ceramics provided a high Curie temperature. A significant enhancement of transduction coefficient (d33g33) is observed. The high d33g33 indicates the possibility of this ceramic for use in EH devices.

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

energy-harvesting
grain size
sintering
dielectric


Twitter user profiling based on text and community mining for market analysis This paper proposes demographic estimation algorithms for profiling Twitter users, based on their tweets and community relationships. Many people post their opinions via social media services such as Twitter. This huge volume of opinions, expressed in real time, has great appeal as a novel marketing application. When automatically extracting these opinions, it is desirable to be able to discriminate discrimination based on user demographics, because the ratio of positive and negative opinions differs depending on demographics such as age, gender, and residence area, all of which are essential for market analysis. In this paper, we propose a hybrid text-based and community-based method for the demographic estimation of Twitter users, where these demographics are estimated by tracking the tweet history and clustering of followers/followees. Our experimental results from 100,000 Twitter users show that the proposed hybrid method improves the accuracy of the text-based method. The proposed method is applicable to various user demographics and is suitable even for users who only tweet infrequently.

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

web mining
text analysis
community analysis
machine learning


A system to test the ground surface conditions of construction sitesfor safe and efficient work without physical strain Ground surface conditions on construction sites have an important influence on the health and safety of workers and their productivity. The development of an expert-based working conditions evaluation system is described, intended to assist site managers in recognising unsatisfactory ground conditions and remedying these. The system was evaluated in the period 20022003. The evaluation shows that companies recognize poor soil/ground conditions as problematic, but are not aware of the specific physical workload hazards. The developed methods allow assessment of the ground surface quality and selection of appropriate measures for improvement. However, barriers exist at present to wide implementation of the system across the industry. Most significant of these is that responsibility for a site's condition is not clearly located within contracting arrangements, nor is it a topic of serious negotiation.

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

construction
physical strain
ground surface conditions


Multi-qudit information splitting with multiple controllers In this paper, we first present a five-party scheme for sharing a single-qutrit state by using GHZ states as the quantum channel. Any one of the agents has the access to reconstruct the original state if other controlling agents cooperate with him. We also sketch the generation of five-party scheme to the case of multi-qudit states and multiple participants by a composite channel composed of generalized Bell states and GHZ states. In our scheme, the physical operations, especially for the controllers and the final receiver, are considerably reduced. It also demonstrates a high degree of symmetry and providesa usefulinspirationfor implementing hierarchical quantum information splitting.

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

quantum state sharing
quantum secret sharing
quantum cryptography


A fast seed detection using local geometrical feature for automatic tracking of coronary arteries in CTA The seed points are detected for automatic coronary artery tracking from CCTA. The computational efficiency is improved using prior knowledge of vessel structure. Using proposed method, a particle filtering-based tracking algorithm is tested. ROC curve analysis shows the advantage of the proposed method.

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 B I O O O O O O O O

coronary computed tomographic angiography (ccta)


Analysis and design of photonic crystal fibers Solid and hollow core fibers through the finite element method Purpose - The aim of this paper is to show the effectiveness of the finite element method (FEM) to study the properties of different kinds of photonic crystal fibers (PCFs), presenting results which highlight the FEM flexibility, exploited according to the particular PCF feature under investigation. Design/methodology/approach - The FEM has been applied to a new emerging class of optical fibers, the so-called PCFs, also known as microstructured or holey fibers. Findings - It has been shown how to design and customize the PCF cross-section to achieve desired values of dispersion, confinement loss, nonlinear or amplification properties. Reported examples prove the FEM ability to deal with complex geometries, arbitrary refractive index steps and distribution, and to be integrated with other approaches for a better and accurate analysis of the considered fiber. Research limitations/implications - Limitation in the FEM use can be given by the required computation effort in terms of memory occupancy and time, even if computational power of modem workstations can attenuate this aspect. Practical implications - The FEM can be a very powerful tool to investigate and design actual structures to be used in several fields, as telecom, sensing, fiber lasers, spectroscopy. Originality/value - The novelty of the paper is given by the exploitation of the FEM feature to design a new emerging class of optical fibers, considering all numerical aspects given by the unusual characteristics of the domain and problem under investigation.

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

finite element analysis
optical properties of materials


A three-dimensional definition for the flexion/extension and abduction/adduction angles Flexion/extension and abduction/adduction, two major parameters for the description of joint rotations, are used to define planer anatomical orientations of body segments. These two-dimensional definitions have been used extensively in the biomechanical literature for reporting and representing both two-dimensional and three-dimensional joint rotations. Whether these traditional two-dimensional measurements represent true joint rotations in three dimensions has not been investigated. A quantitative error analysis is presented to show how large an error can be produced in the flexion/extension and abduction/adduction angles when using two-dimensional measurements to represent three-dimensional joint rotations. The results indicate that for an out-of-plane flexion the error in abduction angle measured by previous methods increases with both flexion and initial abduction angle and become very sensitive when the flexion angle exceeds 40 degrees. Although the error can be less than 2 degrees for flexion below 20 degrees when the initial abduction angle is at 30 degrees, it can be as large as 9 degrees for 60 degrees of flexion with an initial 10 degrees of abduction; nearly double the real abduction angle. Therefore, two-dimensional measurements of flexion/extension and abduction/adduction can be erroneous and overestimated for a three-dimensional joint rotation. To overcome the problem new definitions are proposed for the true flexion/extension and abduction/adduction angles as two independent parameters for three-dimensional joint rotation.

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

flexion/extension
abduction/adduction
joint kinematics
biomechanics
gait analysis
human movement


sparsity issues in the computation of jacobian matrices The knowledge of sparsity information plays an important role in efficient determination of sparse Jacobian matrices. In a recent work, we have proposed sparsity-exploiting substitution techniques to determine Jacobian matrices. In this paper, we take a closer look at the underlying combinatorial problem. We propose a column ordering heuristic to augment the "usable sparsity" in the Jacobian matrix. Furthermore, we present a new elimination technique based on merging of successive columns.

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

sparse jacobians
substitution methods
partition


Building a smart campus to support ubiquitous learning New technological advances in user mobility and context immersion are enabling novel adaptive and pervasive learning models in ambient environments. These advances allow physical learning spaces with embedded computing capabilities to provide an augmented self-aware learning experience. In this paper, we aim at developing a novel ubiquitous learning model within a pervasive smart campus environment. The goal of our research consists of identifying the steps towards building such an environment and the involved learning processes. We define a model of a smart campus, and advocate learning practices in the light of new paradigms such as context-awareness, ubiquitous learning, pervasive environment, resource virtualization, autonomic computing and adaptive learning. We reveal a comprehensive architecture that defines the various components and their inter-operations in a smart educational environment. The smart campus approach is presented as a composition of ambient learning spaces, which are environments where physical learning resources are augmented with digital and social services. We present a model of these spaces to harness future ubiquitous learning environments. One of the distinguished features of this model is the ability to unleash the instructional value of surrounding physical structures. Another one is the provision of a personalized learning agenda when moving across these ambient learning environments. To achieve these goals, we profile learners and augment physical campus structures to advocate context-aware learning processes. We suggest a social community platform for knowledge sharing which involves peer learners, domain experts as well as campus physical resources. Within this pervasive social scope, learners are continuously immersed in a pedagogically supported experiential learning loop as a persuasive approach to learning. A learning path, which responds to learners goals and qualifications, autonomously guides learners in achieving their objectives in the proposed smart campus. We evaluated our ubiquitous learning approach to assert the performance of these building blocks in the proposed smart campus model. The results show interesting tradeoffs and promising insights.

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

pervasive environments
program outcomes
semantic web


Lower-bounding procedures for the 2-dimensional cell suppression problem To protect confidential data from disclosure, statistical offices use a technique called cell suppression which consists of suppressing data from the statistical tables they publish. As some row and column subtotals are published, omitting just the confidential values does not guarantee in every case that they cannot be disclosed or estimated within a narrow range. Therefore to protect confidential data it is often necessary to make complementary suppressions, that is, to suppress also values that are not confidential. Assigning a cost to every complementary suppression, the cell suppression problem is that of finding a set of complementary suppressions with minimum total cost. In this paper new necessary protection conditions are presented. Combining these new conditions with the ones known from the literature new lower-bounding methods for the cell suppression problem are developed. Dominance theoretical results are proven and computational experience is reported for randomly generated tables.

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 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 I O O O O O O O O O O O O O O O O

integer programming
statistical disclosure


On a 5-design related to a putative extremal doubly even self-dual code of length a multiple of 24 By the Assmus and Mattson theorem, the codewords of each nontrivial weight in an extremal doubly even self-dual code of length 24m form a self-orthogonal 5-design. In this paper, we study the codes constructed from self-orthogonal 5-designs with the same parameters as the above 5-designs. We give some parameters of a self-orthogonal 5-design whose existence is equivalent to that of an extremal doubly even self-dual code of length 24m for \(m=3,4,5,6\). If \(m \in \{1,\ldots ,6\}\), \(k \in \{m+1,\ldots ,5m-1\}\) and \((m,k) \ne (6,18)\), then it is shown that an extremal doubly even self-dual code of length 24m is generated by codewords of weight \(4k\).

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


Incremental feature weight learning and its application to a shape-based query system Similarity between shapes is often measured by computing the distance between two feature vectors. Unfortunately, the feature space cannot always capture the notion of similarity in human perception. So, most current image retrieval systems use weights measuring the importance of each feature. However, the similarity does not vary with equal strength or in the same proportion in all directions in the feature space. In this paper, we present feature weights based on both clustered objects in the database and on relevance feedback. We show that using variance information from shape clusters to guide cluster information for an initial database search gives better results than using the standard Euclidean distance. To automatically incorporate a user's need, the proposed shape-based query system uses an incremental feature weight learning method that refines prototypes. In contrast to existing image database systems, the system can learn from user feedback. Indexing and retrieval results are presented that demonstrate the efficacy of our technique using the well-known Columbia database.

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

shape-based query
incremental clustering
weighted feature distance
prototype refinement


Elicitation of neurological knowledge with argument-based machine learning The paper describes the use of expert's knowledge in practice and the efficiency of a recently developed technique called argument-based machine learning (ABML) in the knowledge elicitation process. We are developing a neurological decision support system to help the neurologists differentiate between three types of tremors: Parkinsonian, essential, and mixed tremor (comorbidity). The system is intended to act as a second opinion for the neurologists, and most importantly to help them reduce the number of patients in the gray area that require a very costly further examination (DaTSCAN). We strive to elicit comprehensible and medically meaningful knowledge in such a way that it does not come at the cost of diagnostic accuracy. To alleviate the difficult problem of knowledge elicitation from data and domain experts, we used ABML. ABML guides the expert to explain critical special cases which cannot be handled automatically by machine learning. This very efficiently reduces the expert's workload, and combines expert's knowledge with learning data. 122 patients were enrolled into the study. The classification accuracy of the final model was 91%. Equally important, the initial and the final models were also evaluated for their comprehensibility by the neurologists. All 13 rules of the final model were deemed as appropriate to be able to support its decisions with good explanations. The paper demonstrates ABML's advantage in combining machine learning and expert knowledge. The accuracy of the system is very high with respect to the current state-of-the-art in clinical practice, and the system's knowledge base is assessed to be very consistent from a medical point of view. This opens up the possibility to use the system also as a teaching tool.

O O O O O O O O O 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 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

argument-based machine learning
decision support systems
parkinsonian tremor
essential tremor


Redundant trees for preplanned recovery in arbitrary vertex-redundant or edge-redundant graphs We present a new algorithm which creates redundant trees on arbitrary node-redundant or link-redundant networks, These trees are such that any node is connected to the common root of the trees by at least one of the trees in case of node or link failure. Our scheme provides rapid preplanned recovery of communications with great flexibility in the topology design. Unlike previous algorithms, our algorithm can establish two redundant trees in the case of a node failing in the network. In the case of failure of a communications link, our algorithm provides a superset of the previously known trees.

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

graph theory
multicasting
network recovery
network robustness
routing


A multiobjective genetic algorithm for obtaining the optimal size of a recurrent neural network for grammatical inference Grammatical inference has been extensively studied in recent years as a result of its wide field of application, and in turn, recurrent neural networks have proved themselves to be a good tool for grammatical inference. The learning algorithms for these neural networks, however, have been far less studied than those for feed-forward neural networks. Classical training methods for recurrent neural networks suffer from being trapped in local minimal and having a high computational time. In addition, selecting the optimal size of a neural network for a particular application is a difficult task. This suggests that the problems of developing methods to determine optimal topologies and new training algorithms should be studied. In this paper, we present a multi-objective evolutionary algorithm which is able to determine the optimal size of recurrent neural networks in any particular application. This is specially analyzed in the case of grammatical inference: in particular, we study how to establish the optimal size of a recurrent neural network in order to learn positive and negative examples in a certain language, and how to determine the corresponding automaton using a self-organizing map once the training has been completed.

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

recurrent neural networks
multiobjective genetic algorithm
grammatical inference


Eliminating redundant columns in continuous tour scheduling problems This paper presents a procedure for eliminating redundant columns in generalized set-covering formulations (GSCFs) of continuous tour scheduling problems that are characterized by labor requirements of zero in some planning periods. We describe the procedure and discuss properties of certain scheduling environments that may affect the appropriateness of its use. The procedure was applied to actual labor requirements and problem characteristics associated with 27 United Airlines Airport Stations and reduced the number of columns (tours) by an average of 56%.

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

scheduling theory
mathematical programming


Characterization of Lactic Acid Bacteria and Other Gut Bacteria in Pigs by a Macroarraying Method Lactic acid bacteria (LAB) consist of many genera, Gram-positive, and nonspore-forming micro-organisms; some members being used as probiotics while some others have negative effects on pig health. Bacterial species in the gastrointestinal tract can produce antibacterial substances, reduce serum cholesterol in their host, or can be responsible for growth reduction, diarrhea, and intestinal epithelial damage. It is therefore important for the pig industry to evaluate the impact of food and farm management on the presence of good or bad bacteria and the risk for consumers. This articles focuses on the molecular identification of gut microflora species following different diets given to pigs in UK and correlating the data on growth, health, and welfare. First of all, pig feces were individually collected from sows before and after farrowing and also from piglets before and after weaning over several months. Bacteria colonies were grown on MRS agar plates from feces and DNA was extracted (QIAamp DNA stool kit) and amplified using 16S rDNA (27f and 519r) primers. DNA sequencing and sequence alignment allowed us to identify species-specific zones, which were used as probes in a macroarray system also known as reverse line blot hybridization. Some probes were found to be species specific for the following specie

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


Fast algorithms for finding disjoint subsequences with extremal densities ? We derive fast algorithms for the following problem: given a set of n n points on the real line and two parameters s s and p p , find s s disjoint intervals of maximum total length that contain at most p p of the given points. Our main contribution consists of algorithms whose time bounds improve upon a straightforward dynamic programming algorithm, in the relevant case that input size n n is much bigger than parameters s s and p p . These results are achieved by selecting a few candidate intervals that are provably sufficient for building an optimal solution via dynamic programming. As a byproduct of this idea we improve an algorithm for a similar subsequence problem of Chen et al. [Disjoint segments with maximum density, in: International Workshop on Bioinformatics Research and Applications IWBRA 2005, (within ICCS 2005), Lecture Notes in Computer Science, vol. 3515, Springer, Berlin, pp. 845850]. The problems are motivated by the search for significant patterns in biological data. Finally, we propose several heuristics that further reduce the time complexity in typical instances. One of them leads to an apparently open subsequence sum problem of independent 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 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 O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O 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

holes in data
range prediction
protein torsion angle
protein structure prediction
selection algorithms


G-ROME: semantic-driven capacity sharing among P2P networks Purpose - The purpose of this paper is to propose a model for sharing network capacity on demand among different underloaded and overloaded P2P ROME-enabled networks. The paper aims to target networks of,nodes with highly dynamic workload fluctuations that may experience a burst of traffic and/or massive nodes' failure rates. Design/methodology/approach - The paper shows that when locally available network capacity is not adequate for the workload requirements, the excessive capacity needs to be sought into other networks with more availability. A random flat P2P overlay of the ROME servers is used for the discovery and movement of nodes between two networks. Centralised or decentralised DHT-based directories of available nodes cannot cope with high workload fluctuations and frequent join/leave actions of nodes. The paper also introduces semantics to refine the answers to the ones with the most appropriate nodes for the requesting network and to find the requested capacity faster and more efficiently. The behaviour of the model is simulated to evaluate with several experiments the model based on some metrics. Findings - The paper finds that all the user queries of an overloaded underlying network are dropped if G-ROME is not used but as G-ROME overlay satisfies the requested capacity of a ROME server, its Chord ring size increases. In case of uniformly distributed and/or plentiful capacity over the overlay, shallow searches may give very good results. On the contrary, deeper searches are required for scarce capacity but the number of messages increases almost exponentially. Originality/value - This paper provides a model for moving the required resources to the requesting job environment rather than the job and its context to the resource.

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


evaluating sources of query expansion terms This study investigates the effectiveness of retrieval systems and human users in generating terms for query expansion. We compare three sources of terms: system generated terms, terms users select from top-ranked sentences, and user generated terms. Results demonstrate that overall the system generated more effective expansion terms than users, but that users' selection of terms improved precision at the top of the retrieved document list.

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


The FERET evaluation methodology for face-recognition algorithms Two of the most critical requirements in support of producing reliable face-recognition systems are a large database of facial images and a testing procedure to evaluate systems. The Face Recognition Technology (FERET) program has addressed both issues through the FERET database of facial images and the establishment of the FERET tests. To date, 14,126 images from 1,199 individuals are included in the FERET database, which is divided into development and sequestered portions of the database. In September 1996, the FERET program administered the third in a series of FERET face-recognition tests. The primary objectives of the third test were to 1) assess the slate of the art, 2) identify future areas of research, and 3) measure algorithm performance.

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


A butterfly structure for rate 2/n convolutional codes In this letter, we propose a butterfly structure for rate 2/n convolutional codes to reduce the computational complexity of Viterbi decoders. By using the butterfly structure, the branch metric computation complexity of some best known codes can be reduced by a factor of 2 or 4.

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


Bayesian belief network learning algorithms for modeling contextual relationships in natural imagery: a comparative study This paper presents a comparative study of Bayesian belief network structure learning algorithms with a view to identify a suitable algorithm for modeling the contextual relations among objects typically found in natural imagery. Four popular structure learning algorithms are compared: two constraint-based algorithms (PC proposed by Spirtes and Glymour and Fast Incremental Association Markov Blanket proposed by Yaramakala and Margaritis), a score-based algorithm (Hill Climbing as implemented by Daly), and a hybrid algorithm (Max-Min Hill Climbing proposed by Tsamardinos et al.). Contrary to the belief regarding the superiority of constraint-based approaches, our empirical results show that a score-based approach performs better on our context dataset in terms of prediction power and learning time. The hybrid algorithm could achieve similar prediction performance as the score-based approach, but requires longer time to learn the desired network. Another interesting fact the study has revealed is the existence of strong correspondence between the linear correlation pattern within the dataset and the edges found in the learned networks.

B I I 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 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


on extending the functions of a relational database system Relational database systems are attracting great interest from potential users outside the traditional areas in which such systems have been employed. Features of modern relational systems such as powerful query facilities, data and device independence, concurrency control, and recovery are useful in applications such as engineering design, office automation, and graphics. However, such applications place demands on the system that it must be extended to handle. This paper identifies three of these demands: storing non-coded information of arbitrary length within the database, dealing with aggregate objects as a unit, and improving support for interactive access. Additions to System R, a prototypical relational system, are introduced to satisfy these demands: long fields, for storing non-coded data, and complex objects, which declare the semantic relationships among data items and provide a means for adequately supporting interactive access.

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

place
applications
recovery
relationships
systems
users
semantic
aggregate
concurrency control
design
data
support
graphics
access
paper
database
automation
query

interaction
engine
object
relation
feature
informal
relational database
device-independence


A stochastic programming approach for gas detector placement using CFD-based dispersion simulations A stochastic programming formulation is developed for determining the optimal placement of gas detectors in petrochemical facilities. FLACS, a rigorous gas dispersion package, is used to generate hundreds of scenarios with different leak locations and weather conditions. Three problem formulations are investigated: minimization of expected detection time, minimization of expected detection time including a coverage constraint, and a placement based on coverage alone. The extensive forms of these optimization problems are written in Pyomo and solved using CPLEX. A sampling procedure is used to find confidence intervals on the optimality gap and quantify the effectiveness of detector placements on alternate subsamples of scenarios. Results show that the additional coverage constraint significantly improves performance on alternate subsamples. Furthermore, both optimization-based approaches dramatically outperform the coverage-only approach, making a strong case for the use of rigorous dispersion simulation coupled with stochastic programming to improve the effectiveness of these safety systems. (C) 2012 Published by Elsevier Ltd.

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

gas leak detection
process safety
sensor placement
mixed-integer linear programming


a multimodal predictive-interactive application for computer assisted transcription and translation Traditionally, Natural Language Processing (NLP) technologies have mainly focused on full automation. However, full automation often proves unnatural in many applications, where technology is expected to assist rather than replace the human agents. In consequence, Multimodal Interactive (MI) technologies have emerged. On the one hand, the user interactively co-operates with the system to improve system accuracy. On the other hand, multimodality improves system ergonomics. In this paper, we present an application that implements such MI technologies. First, we have designed an Application Programming Interface (API), featuring a client-server framework, to deal with most common NLP MI tasks. Second, we have developed a generic client application. The resulting client-server architecture has been successfully tested with two di erent NLP problems: transcription of text images and translation of texts.

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

interactive framework
handwritten recognition
machine translation


Network Reliability Modeling Under Stochastic Process of Component Failures The concept of D-spectrum is a useful tool to investigate the reliability and stochastic properties of networks. In this paper, we consider a network consisting of components (links or nodes), and assume that the network has two states: up, and down. We study the D-spectrum-based reliability of the network under the assumption that the components are subject to failure according to a counting process. Mixture representation of the reliability of the network lifetime is given in terms of the reliability functions of arrival times. It is shown that, when the D-spectra of two networks are stochastically ordered, then under some conditions the lifetimes of two networks are also stochastically ordered. Under the special case when the process of the failure of the components is a nonhomogeneous Poisson process, we arrive at a mixture representation for the reliability function of the network lifetime, and explore several stochastic and aging properties of the network lifetime under different scenarios. The failure rate of the network lifetime and its asymptotic behavior is investigated. D-spectrum based representation theorems are also given on the basis of the stochastic precedence concept.

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

nonhomogeneous poisson process
stochastic precedence

d-spectrum
increasing failure rate
record values
stochastic ordering
system signature
two-state networks


Fuzzy parametric sample selection model: Monte Carlo simulation approach Over a few decades, regression model has received considerable attention and has been shown to be successful when applied together with other models. One of the most successful models is the sample selection model or the selectivity model. However, uncertainties and ambiguities do exist in the models, particularly the relationship between the endogenous and exogenous variables. Therefore, it will disrupt the ability and effectiveness of the model proceeded to give the estimated value that can explain the actual situation of a phenomenon. These are the questions and problems that are yet to be explored and the main aim of this study. A new framework for estimation of the sample selection model using the concept of fuzzy modelling is introduced. In this approach, a flexible fuzzy concept hybrid with the parametric sample selection model is known as fuzzy parametric sample selection model (FPSSM). The elements of vagueness and uncertainty in the models are represented in the model construction, as a way of increasing the available information to produce a more accurate model. This led to the development of the convergence theorem presented in the form of triangular fuzzy numbers to be used in the model. Consistency is an indicator of effectiveness of the developed models and justified using Monte Carlo simulation. Consistency and efficiency of the proposed model are considered in this study. In order to achieve that condition, a Monte Carlo simulation is used. Hence, the error terms of FPSSM are assumed to follow the normal and the chi-square distributions. Simulation results show that FPSSM is consistent and efficient when its distributions are normal. Instead, the FPSSM by chi-square distribution is found to be inconsistent.

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

sample selection model
vagueness and uncertainty
monte carlo simulation
consistency and efficiency


Some experimental investigation of the effect of railway tunnels on mobile communications in Western India Establishing of mobile communications in guided structures like railway tunnels, coal mines, etc., is gaining increasing importance due to the passage of high speed and high density of trains in tunnels and for monitoring of information on safety of workers and day-to-day operations in various mines. The present study reports investigation of mobile communication experiments in ultra high frequency band in railway tunnels of western India conducted in a moving train both in uplink and downlink directions. The observed signal fluctuations are discussed in terms of tunnel characteristics and different modes of propagation in tunnels and compared with model deduced values.

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


movement-aware alternative path routing protocol for vehicular multi-hop communications Vehicular Ad-hoc Networks (VANETs) are now considered to be suitable for enhancing road safety and efficiency in vehicular environment. Especially, due to the affluent spectrum resource, supports for non-safety relevant services, like inter-vehicle entertainments, are also under investigation. However, in the vehicular environments, the nodes can experience frequent link breakages due to the vehicle mobility characteristic. Thus, a reliable multi-hop routing protocols is definitely needed to overcome the performance degradation caused by it. In this paper, we propose a novel scheme for non-safety applications, which is also referred as Movement-aware Alternative path Routing Protocol (MARP), a reactive unicast routing protocol that considers two factors such as vehicle movement and multi-path to determine the optimum reliable routing paths. In addition, we devote special attention to the random characteristic of the radio propagation model to provide a simulation with the desired level of realism. After realistic simulation studies, the performance of proposed MARP routing protocol outperforms the traditional VANETs routing by reducing the routing overhead and enhancing the stability of routing path.

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 B I I 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

ad-hoc routing
vehicular multi-hop communications
connectivity prediction


Kirkman frames having hole type h(u)m(1) for small h We begin an investigation into the spectrum of (non-uniform) Kirkman frames of type h(u) m(1), paying particular attention to the cases where h is an element of {2,4,6,8,10,12}. We show that for each of these values of h the obvious necessary conditions on u, m are sufficient in all but at most 24 cases of (h,u,m).

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

group divisible designs
double group divisible designs
incomplete group divisible designs


Comparative study of the server-initiated lowest algorithm using a load balancing index based on the process behavior for heterogeneous environment The availability of low cost microcomputers and the evolution of computer networks have increased the development of distributed systems. In order to get a better process allocation on distributed environments, several load balancing algorithms have been proposed. Generally, these algorithms consider as the information policy's load index the length of the CPU's process waiting queue. This paper modifies the Server-Initiated Lowest algorithm by using a load index based on the resource occupation. Using this load index the Server-Initiated Lowest algorithm is compared to the Stable symmetrically initiated, which nowadays is defined as the best choice. The comparisons are made by using simulations. The simulations showed that the modified Server-Initiated Lowest algorithm had better results than the Symmetrically Initiated one.

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

load balancing algorithm
high performance
parallel and distributed computing


Experience report: A pure shirt fits reflections on Haskell at Bluespec Bluespec is a hardware-design tools startup whose core technology is developed using Haskell. Haskell is an unusual choice for a startup because it adds technical risk to the inherent business risk. In the years since Bluespec's founding, we have discovered that Haskell's purity is an unexpected match for the development needs of a startup. Based on Bluespec's experience, we conclude that pure programming languages can be the source of a competitive advantage for startup software companies.

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


capacity-optimum mode switching strategies over a cooperative relay network In this paper, we deal with two mode switching strategies for capacity-optimum transmission over a cooperative relay network. Both of them switch the transmission mode back and forth between a cooperative mode and a non-cooperative mode based on their corresponding spectral efficiencies. We use the distributed Alamouti code [1] for the cooperative mode transmission. The first strategy uses the same frame structure in both the cooperative and non-cooperative modes. In the cooperative mode, a source node S transmits two signals to a relay node R and a destination node D over two consecutive time slots during the 1 st phase. During the 2 nd phase, S and R transmit again cooperatively the same set of the above two signals to D over two consecutive time slots according to the Alamouti encoding rule, and then D detects jointly the two signals received over two consecutive phases. Sometimes a spectral efficiency of the S-D link might be higher than that of the S-R link. In such a case, cooperative transmission might not be better any longer and non-cooperative transmission in which D does not take any relayed replicas of the two signals would be recommended. We also introduce the 2 nd disruptive strategy that changes disruptively the frame structure between the cooperative and non-cooperative modes in order to utilize best the radio resource in the non-cooperative mode. In the non-cooperative mode, one signal for every slot is transmitted only through the S-D link with no interruption for relaying. Numerical and simulation results show that the second one can provide almost twice the spectral efficiency than the first one does, though it may need a little forward signaling that S notifies the mode change status to D. The performance of the second strategy gets improved more significantly as the signal-to-noise ratio (SNR) of the S-R link is getting low and/or the SNR of the S -D link is getting high.

O B I O O O B I 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 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 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 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

mode switching
cooperative relay
distributed alamouti code
spectral efficiency


Visual soil water status indicator for improved irrigation management ? A device to aid in irrigation scheduling by visually indicating current soil water status relative to an upper and lower set point was developed and field tested. The device can be used by farm managers to easily evaluate current soil water status from a distance. This information can be used to guide irrigation scheduling decisions throughout the season. Seven farm managers evaluated the device on seven commercial potato fields. Two study fields, one with and one without soil water status indicators, were established with each farm manager. Water application was measured in each field. Collectively, farm managers applied 7% (2.9 cm) less water to fields with the soil water status indicators than comparison fields. Average water application was significantly less (P=0.04) for fields with soil water status indicators. The basic elements of the soil water status indicator and its operation are presented.

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 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

irrigation scheduling
irrigation management


The maintenance and evolution of resource-constrained embedded systems created using design patterns Most previous work on pattern-based software development has focused on the process of system creation rather than on the post-creation project phases (such as maintenance and evolution). In the study reported in this paper, we present the results from a short series of empirical studies in which we examined techniques for exchanging patterns used in an embedded design after the project had been completed. When exchanging patterns at this time, our aim was to identify the implementation of the pattern of interest in the system code and then substitute a suitable version of the replacement pattern. Findings are presented both from two small test projects, and from a more realistic case study. The results obtained suggest that this approach has considerable potential.

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

pattern implementations
software maintenance


Algebraic geometry and computer vision: Polynomial systems, real and complex roots We review the different techniques known for doing exact computations on polynomial systems. Some are based on the use of Grobner bases and linear algebra, others on the more classical resultants and its modern counterparts. Many theoretical examples of the use of these techniques are given. Furthermore, a full set of examples of applications in the domain of artificial vision, where many constraints boil down to polynomial systems, are presented. Emphasis is also put on very recent methods for determining the number of (isolated) real and complex roots of such systems.

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

symbolic computation
computer vision applications


A 0.31-1 GHz Fast-Corrected Duty-Cycle Corrector With Successive Approximation Register for DDR DRAM Applications This brief presents a duty cycle corrector (DCC) using a binary search algorithm with successive approximation register (SAR). The proposed DCC consists of a duty-cycle detector, a duty-cycle adjuster, its controller and an output buffer. In order to achieve fast duty-correction with a small die area, a SAR-controller is exploited as a duty-correction controller. The proposed DCC circuit has been implemented and fabricated in a 0.13-mu m CMOS process and occupies 0.048 mm(2). The measured duty-cycle error for the 50% duty-rate is below +/- 1% (or +/- 10 pS) within +/- 320 pS external input duty-cycle error. The duty of output signal is corrected only with 14 cycles. This DCC operates from 312.5 MHz to 1 GHz and dissipates 3.2 mW at 1 GHz.

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

successive approximation register (sar) controller


RANDOMISATION AND DERANDOMISATION IN DESCRIPTIVE COMPLEXITY THEORY We study probabilistic complexity classes and questions of derandomisation from a logical point of view. For each logic L we introduce a new logic BPL, bounded error probabilistic L, which is defined from L in a similar way as the complexity class BPP, bounded error probabilistic polynomial time, is defined from P. Our main focus lies on questions of derandomisation, and we prove that there is a query which is definable in BPFO, the probabilistic version of first-order logic, but not in C-infinity omega(omega), finite variable infinitary logic with counting. This implies that many of the standard logics of finite model theory, like transitive closure logic and fixed-point logic, both with and without counting, cannot be derandomised. Similarly, we present a query on ordered structures which is definable in BPFO but not in monadic second-order logic, and a query on additive structures which is definable in BPFO but not in FO. The latter of these queries shows that certain uniform variants of AC(0) (bounded-depth polynomial sized circuits) cannot be derandomised. These results are in contrast to the general belief that most standard complexity classes can be derandomised. Finally, we note that BPIFP+C, the probabilistic version of fixed-point logic with counting, captures the complexity class BPP, even on unordered structures.

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

descriptive complexity
probabilistic complexity classes
derandomisation


Radial vibration measurements directly from rotors using laser vibrometry: The effects of surface roughness, instrument misalignments and pseudo-vibration Laser Doppler vibrometry (LDV) offers an attractive solution when radial vibration measurement directly from a rotor surface is required. Research to date has demonstrated application on polished-circular rotors and rotors coated with retro-reflective tape. In the latter case, however, a significant cross-sensitivity to the orthogonal radial vibration component occurs and post-processing is required to resolve individual radial vibration components. Until now, the fundamentally different behaviour observed between these cases has stood as an inconsistency in the published literature, symptomatic of the need to understand the effect of surface roughness. This paper offers the first consistent mathematical description of the polished-circular and rough rotor behaviours, combined with an experimental investigation of the relationship between surface roughness and cross-sensitivity. Rotors with surface roughness up to 10nm satisfy the polished-circular rotor definition if vibration displacement is below 100% beam diameter, for a 90?m beam, and below 40% beam diameter, for a 520?m beam. On rotors with roughness between 10nm and 50nm, the polished-circular rotor definition is satisfied for vibration displacements up to 25% beam diameter, for a 90?m beam, and up to 10% beam diameter, for a 520?m beam. As roughness increases, cross-sensitivity increases but only rotors coated in retro-reflective tape satisfied the rough rotor definition fully. Consequently, when polished-circular surfaces are not available, rotor surfaces must be treated with retro-reflective tape and measurements post-processed to resolve individual vibration components. Through simulations, the value of the resolution and correction algorithms that form the post-processor has been demonstrated quantitatively. Simulations incorporating representative instrument misalignments and measurement noise have enabled quantification of likely error levels in radial vibration measurements. On a polished-circular rotor, errors around 0.2% for amplitude and 2mrad for phase are likely, rising a little at the integer orders affected by pseudo-vibration. Higher pseudo-vibration levels and the need for resolution increase errors in the rough rotor measurements, especially around the synchronous frequency where errors reach 20% by amplitude and 100mrad for phase. Outside a range of half an order either side of first order, errors are ten times lower and beyond fifth order errors are similar to those for the polished-circular rotor. Further simulations were performed to estimate sensitivities to axial vibration, speed variation and bending vibrations.

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

laser vibrometry
radial vibration
rotor
surface roughness


The impact of critical sporadic jobs on gang scheduling performance in distributed systems A commonly used task scheduling algorithm for parallel and distributed systems is gang scheduling. In this paper, we study gang scheduling performance in the presence of critical sporadic jobs. A simulation model is used to address performance issues associated with gang scheduling on distributed processors for various workloads. Simulated results indicate that the relative performance of the gang scheduling policies depends on the arrival rates of gangs and critical sporadic jobs and also on the variability in the critical sporadic jobs inter-arrival times.

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

scheduling policies
distributed systems
performance
simulation


Role of Cdk5 in Drug Abuse and Plasticity Neuronal plasticity serves as the basis for learning and memory in the adult brain. Contextual, motor, and reward-based learning are important in reinforcing survival behavior in animals. Most psychostimulant drugs of abuse target the dopaminergic reward system of the brain. Drugs of abuse cause long-standing cellular and molecular neuroadaptations in the brain. The neuronal protein kinase Cdk5 is emerging as an important player in the cellular and physiological responses to drugs of abuse. Substantial evidence indicates that Cdk5 controls dopamine neurotransmission through regulation of the protein phosphatase-1 inhibitor, DARPP-32. Furthermore, the morphological changes associated with chronic cocaine exposure are dependent on Cdk5. Thus, Cdk5 mediates cellular responses to psychostimulant drug-induced changes in dopamine signal transduction and cytoskeletal reorganization. In this regard, Cdk5, through its targeting of various substrates, integrates a number of intracellular pathways that are targeted by psychostimulant drugs. These studies and the emerging role of Cdk5 in various forms of neuronal plasticity are reviewed.

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


Memory-enhanced MMSE decoding in vector quantization An approach to minimum mean-squared error (MMSE) decoding for vector quantization over channels with memory is presented. The decoder is based on the Gilbert channel model that allows the exploitation of both intra- and inter-block correlation of bit error sequences. We also develop a recursive algorithm for computing the a posteriori probability of a transmitted index sequence, and illustrate its performance in quantization of Gauss-Markov sources under noisy channel conditions.

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

mmse decoding
vector quantization
gilbert channel


structure and parameter estimation for cell systems biology models In this work we present a new methodology for structure and parameter estimation in cell systems biology modelling. Our modelling framework is based on P systems, an unconventional computational paradigm that abstracts from the structure and functioning of the living cell. The process of designing models, consisting of both the optimisation of the modular structure and of the stochastic kinetic parameters, is performed using a memetic algorithm. Specically, we use a nested evolutionary algorithm where the first layer evolves rule structures while the inner layer, implemented also as a genetic algorithm (GA), fine tunes the parameters of the model. Our approach consists of an incremental methodology. Starting from very simple P system modules specifying basic molecular interactions, more complicated modules are produced to model more complex molecular systems. These newly found modules are in turn added to the library of available P systems modules so as to be used subsequently to develop more intricate and circuitous cellular models. The effectiveness of the algorithm was tested on three case studies, namely, molecular complexation, enzymatic reactions and autoregulation in transcriptional networks.

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

memetic algorithm
p systems
systems biology

modular biology
genetic algorithms
synthetic biology


Spatial and frequency domain techniques for segmentation of Placido images and accuracy implications for videokeratography Videokeratography (VK) has been a widespread technology for corneal surface analysis since the mid 1980s. Most manufactures use personal computers attached to a Placido disc apparatus in order to capture and process digital images. Although precision reported by most manufactures are within very good limits, none of them have disclosed, probably due to proprietary reasons, the nature of the algorithm used in their image-processing phase. This is a problem when researchers want to reproduce or test their own curvature or elevation algorithms on Placido images generated on different commercial videokeratographs or even compare their algorithms on data from different manufactures. Our main objective in this work was to develop certain basic techniques for Placido image edge detection and to compare the results of each algorithm in terms of precision at the image level and also the consequences for axial curvature computations. We also propose that manufactures come forward and at least explain which image-processing technique is used in their own algorithms so other researchers and laboratories can make better use of their data to improve VK algorithms. Placido images from an Eyesys system 2000 were captured for four different spherical surfaces. Each image was saved in bitmap format at the hard disk of an IBM computer. Six different image-processing algorithms were developed using different techniques well documented in the literature. The six methods were as follows: (1) first order numerical derivative, (2) first and (3) second order Fourier derivative, (4) the MarrHildreth filter, (5) Canny's method and (6) Mathematical Morphology. Each algorithm was tested on each of the Placido images. Edge radial distance from center of Placido image was compared for each algorithm and a computer simulation of the VK system. The simulated image was used as absolute reference. Another approach was to calculate Axial dioptric power using, again, well documented procedures, and compare the results for each image detection algorithm. Mean deviation in terms of pixels/millimeters/dioptric power for all spheres for methods (16) were, respectively, (1) 33.1695/0.7961/0.79, (2) 32.79/0.7870/0.7724, (3) 60.7150/1.4572/1.4192, (4)18.97/0.4553/0.4572, (5) 46.33/1.1119/1.0917 and (6) 20.55/0.4932/0.48. All methods have great deviation propagation in terms of dioptric power calculations when the axial algorithm is used and the absolute reference simulated edges are used to generate the calibration curves. This indicates that researchers should be more careful when using resulting image processing files from different videokeratographs to compare their own curvature or elevation algorithms among different instruments or even to measure the absolute precision of their new algorithms.

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

corneal topography
placido discs
signal processing


Hybrid Estimation of Distribution Algorithm for the Quay Crane Scheduling Problem The competitiveness of a container terminal is highly conditioned by the time that container vessels spend on it. The proper scheduling of the quay cranes can reduce this time and allows a container terminal to be more attractive to shipping companies. The goal of the Quay Crane Scheduling Problem (QCSP) is to minimize the handling time of the available quay cranes when performing the tasks of loading and unloading containers onto/from a container vessel. This paper proposes a hybrid Estimation of Distribution Algorithm with local search to solve the QCSP. This approach includes a priori knowledge about the problem in the initialization step to reach promising regions of the search space as well as a novel restarting strategy with the aim of avoiding the premature convergence of the search. Furthermore, an approximate evaluation scheme is applied in order to reduce the computational burden. Moreover, its performance is statistically compared with the best optimization method from the literature. Numerical testing results demonstrate the high robustness and efficiency of the developed technique. Additionally, some relevant components of the scheme are individually analyzed to check their effectiveness.

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

quay crane scheduling problem
container terminal
estimation of distribution algorithm
local search


A QoS Architecture for Real-Time Transactions Guarantee in Mobile Ad Hoc Networks Many real-time applications, handling a large amount of data, require a real-time database system, RTDBS, which provides adequate mechanisms to guarantee time constraints during transaction execution and data access. Deploying real-time applications using data services in mobile ad hoc networks (MANETs) implies several constraints. The key challenging is providing the application time constrained services with node limited resources. Indeed, the mobile nodes lifetime has to face unpredictable requests leading to an overload, a battery exhaustion or a service unavailability. In this work, we propose a quality of service, QoS, architecture to handle real-time transaction execution in MANETs. Appropriate parameters are needed to capture the unstable system behavior and the limited autonomy. The proposed architecture is based on a cross-layer approach and integrates the network layer QoS parameters with the ones specified at the application layer, useful in the service selection step. The proposed solution includes (i) an energy and delay aware routing protocol and (ii) a cross-layer service selection protocol, ensuring both timeliness and energy efficiency by avoiding low-power and busy service provider nodes. Simulation results prove that the protocols offered within the cross-layer architecture, decrease the deadline miss ratio of packets, increase the service availability and extend the network lifetime.

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 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 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

real-time database system
delay guarantee
cross-layering
mobile ad hoc network


SPH simulation of transition to turbulence for planar shear flow subjected to a streamwise magnetic field Active flow control of electrically conducting fluids finds growing importance in the metallurgical industry. A magnetic field applied in the streamwise direction of electrically conducting fluid flow restrains the velocity fluctuations in the transverse plane and the transition to turbulence may be delayed. The smoothed particle hydrodynamic (SPH) methodology is employed to interpret this concept. To this purpose, the onset of turbulence is related to the transitional organization of the SPH fluid particle structure or to the temporal history of the turbulence-related quantities during the early stages of the transition to turbulence. The results put in evidence the ability of a streamwise magnetic field on controlling the transition to turbulence of an electrically conducting fluid flow, i.e., the transition to turbulence may be distinctly delayed in the fluid flow subjected to a streamwise magnetic field. Furthermore, if the applied streamwise magnetic field is strong enough, the Reynolds stress in the streamwise direction may be dominant over the transverse counterpart, and turbulence is anisotropic as only in the streamwise direction of the fluid flow, the Reynolds stress is detectable.

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

smoothed particle hydrodynamics
magnetohydrodynamics
turbulence control
cfd


A Mixed Methods Approach to Technology Acceptance Research The aim of this paper is to discuss the significance and potential of a mixed methods approach in technology acceptance research. After critically reviewing the dominance of the quantitative survey method in TAM-based research, this paper reports a mixed methods study of user acceptance of emergency alert technology in order to illustrate the benefits of combining qualitative and quantitative techniques in a single study. The main conclusion is that a mixed methods approach provides opportunities to move beyond the vague conceptualizations of "usefulness" and "ease of use" and to advance our understanding of user acceptance of technology in context.

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


Spatialhistorical landscapes of telecommunication network survivability Network security and survivability are critical components of the global telecommunication infrastructure. However, due to a string of recent events, including the attacks on the World Trade Center, the ability of this infrastructure to provide a robust platform for the movement of critical financial, political and cultural information is in doubt. In the United States, both law enforcement and national security agencies are questioning the fundamentals of network security and survivability. This resurgence of interest in telecommunication network performance (particularly the Internet) by the US government is not only cyclical in nature, but has a decidedly geographic component. The purpose of this paper is to trace the evolution of telecommunication network survivability from the Cold War era to the present day, paying particular attention to its spatial manifestations. This includes an extended examination of network topology and survivability. In addition, this paper utilizes basic statistical analysis and a geographic information system to empirically examine a series of legacy communication bunkers scattered throughout the US. Results suggest that their locations were not only strategic during the 1960s, but remain geographically strategic today.

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

infrastructure
network security
survivability


The real-time urban traffic control system CRONOS: Algorithm and experiments The real-time urban traffic control algorithm CRONOS has been evaluated on an intersection by comparison of two reference control strategies, a local one and a centralized one. Recurrent traffic situations, from peak hour traffic to low traffic, have been studied, and the impact on the traffic from a fluidity point of view has been investigated using various criteria. The average behavior of CRONOS has also been analyzed by crossing the traffic signal colors with traffic variables. Several of the criteria are innovative, thanks to the real-time, accurate video-based traffic data collected. The results show high benefits of CRONOS on the total delay compared to the two reference control strategies, and benefits are also obtained on the total number of stops and percentage of stops, especially in comparison with the local strategy. All traffic situations (peak to low traffic) are concerned by these results. The analysis of the average behavior of CRONOS shows a higher average number of cycles per hour, more global green duration per hour at the center of the intersection, to the detriment of the entries. Moreover, CRONOS switches more often from amber to red when no vehicles are present on the link in percentage of cycles or in number of cycles per hour; it switches more often from green to amber when vehicles are present on the link in percentage of cycles per hour.

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

signalized intersection
real-time control strategy
on-field assessments
impact on fluidity traffic criteria
control strategy behavior


Bridging the fuzzy, neural and evolutionary paradigms for automatic target recognition Multilayer perceptron neural networks possess pattern recognition properties that make them well suited for use in automatic target recognition systems. Their application is hindered, however, by the lack of a training algorithm, which reliably finds a nearly global optimal set of weights in a relatively short time. The approach presented here is based on implementation of genetic algorithms and fuzzy logic in training the proposed hybrid architecture. Compared to other approaches, it offers the following three main advantages. The neuro-computing technique is capable of fast and adaptive distortion-invariant pattern recognition for rapidly changing targets. On the other hand, genetic algorithms and fuzzy logic offer very sophisticated configuration control, which combines the results of previous computations with the external operating environment. Third, it allows us to significantly improve the reliability of object detection in the input scene with respect to associated distortions at no additional computational cost. This paper examines using genetic algorithms as an efficient way to train a feedforward neural net, the inputs for which are provided by a fuzzy front end, to be applied to automatic target recognition. The system is tested using actual laser detection and range data as training data and the results of the analysis show that the proposed system results in a much faster convergence on a weight set, and a high rate of successful recognition.

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

fuzzy logic
automatic target recognition

feedforward neural networks
genetic algorithm


Periodic synchronization control of discontinuous delayed networks by using extended Filippov-framework ? This paper is concerned with the periodic synchronization problem for a general class of delayed neural networks (DNNs) with discontinuous neuron activation. One of the purposes is to analyze the problem of periodic orbits. To do so, we introduce new tools including inequality techniques and Kakutanis fixed point theorem of set-valued maps to derive the existence of periodic solution. Another purpose is to design a switching state-feedback control for realizing global exponential synchronization of the driveresponse network system with periodic coefficients. Unlike the previous works on periodic synchronization of neural network, both the neuron activations and controllers in this paper are allowed to be discontinuous. Moreover, owing to the occurrence of delays in neuron signal, the neural network model is described by the functional differential equation. So we introduce extended Filippov-framework to deal with the basic issues of solutions for discontinuous DNNs. Finally, two examples and simulation experiments are given to illustrate the proposed method and main results which have an important instructional significance in the design of periodic synchronized DNNs circuits involving discontinuous or switching factors.

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

periodic synchronization
neural networks

functional differential inclusions
filippov-framework
discontinuous neuron activations
switching state-feedback control


RFID-based traceability in the supply chain Purpose - The paper aims to propose a novel dynamic tracing task model to enhance the traceability range along the supply chain beyond simple distribution channels. It further extends the study by implementing the system architecture with the proposed data model to support the dynamic tracing task. Design/methodology/approach - Typical processes of supply chain in manufacturing industries using bill of material data to extract and define information requirements are followed. The data elements are systematically selected and explained in the proposed model step by step. Findings - This paper found that existing Radio Frequency IDentification (RFID) data management scheme has to be modified so as to provide end-to-end traceability. Research limitations/implications - Validation of the proposed model and system architecture should be done through actual implementation in industrial settings. Practical implications - The paper gives an insight to many system managers and executors in how full traceability along the supply chain can actually be realized. Originality/value - Several studies have discussed the traceability issues but failed to construct a system and methodologies to obtain the full traceability range. However, this paper contributes by presenting the specific methodological steps which can provide powerful solutions to build a system for traceability, exploiting RFID technology.

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

supply chain management
radio frequencies
modelling
tracer methods


Password-based user authentication and key distribution protocols for client-server applications Up to now, most of the literature on three-party authentication and key distribution protocols has focused on the environment in which two users (clients) establish a session key through an authentication server. In this paper, we discuss another environment in which a user (client) requests service from an application server through an authentication server. We propose two secure and efficient authentication protocols (KTAP: key transfer authentication protocol and KAAP: key agreement authentication protocol) to fit this environment. These two proposed protocols can be efficiently applied to various communication systems in distributed computing environments since they provide security, efficiency, and reliability. (C) 2003 Elsevier Inc. All rights reserved.

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

authentication
key agreement
key transfer


Finding an internal state of RC4 stream cipher The RC4 is a stream cipher widely deployed in software applications due to its simplicity and efficiency. The paper presents a cryptanalytic attack that employs the tree representation of this cipher and introduces an abstraction in the form of general conditions for managing the information about its internal state. In order to find the initial state, the tree of general conditions is searched applying the hill-climbing strategy. The complexity of this attack is lower than that of an exhaustive search. The attack is derived from a general cryptanalytic approach for a class of table-shuffling ciphers, whose next-state function permutes the table entries. Incorporating the general conditions in the existing backtracking algorithm, the estimated complexity of the cryptanalytic attack is decreased below the best published result but the RC4 still remains a quite secure cipher in practice. (c) 2006 Elsevier Inc. All rights reserved.

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


Absence of inelastic collapse for a ID gas of grains with an internal degree of freedom in a cooling gas of rigid particles interacting with a constant coefficient of restitution, groups of particles within the gas may experience an infinite number of collisions in a finite time. This singularity, named inelastic collapse, is a shortcoming of the mathematical model, and it hampers the efforts of simulating a freely evolving, cooling granular system. After a brief review of previous works addressing the problem, we propose a one-dimensional model where a grain is seen as a pair of point masses joined by a massless, dissipative spring. We show that binary interactions of such grains are described as impacts with a constant restitution coefficient, whose expression is given in terms of the spring parameters. However, the impact is not instantaneous, but it requires a finite time. We show that in situations that would lead to inelastic collapse, multiple interactions among grains transfer kinetic energy into potential energy associated with the deformation of the springs, rather than dissipate it. This effectively avoids the collapse. Finally, we discuss the results of the simulations of a cooling granular system in comparison with other models. (c) 2007 Elsevier Ltd. All rights reserved.

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

inelastic collapse
restitution coefficient


A high order cell-centered semi-Lagrangian scheme for multi-dimensional kinetic simulations of neutral gas flows The term Convected Scheme (CS) refers to a family of algorithms, most usually applied to the solution of Boltzmanns equation, which uses a method of characteristics in an integral form to project an initial cell forward to a group of final cells. As such the CS is a forward-trajectory semi-Lagrangian scheme. For multi-dimensional simulations of neutral gas flows, the cell-centered version of this semi-Lagrangian (CCSL) scheme has advantages over other options due to its implementation simplicity, low memory requirements, and easier treatment of boundary conditions. The main drawback of the CCSL-CS to date has been its high numerical diffusion in physical space, because of the 2nd order remapping that takes place at the end of each time step. By means of a modified equation analysis, it is shown that a high order estimate of the remapping error can be obtained a priori, and a small correction to the final position of the cells can be applied upon remapping, in order to achieve full compensation of this error. The resulting scheme is 4th order accurate in space while retaining the desirable properties of the CS: it is conservative and positivity-preserving, and the overall algorithm complexity is not appreciably increased. Two monotone (i.e. non-oscillating) versions of the fourth order CCSL-CS are also presented: one uses a common flux-limiter approach; the other uses a non-polynomial reconstruction to evaluate the derivatives of the density function. The method is illustrated in simple one- and two-dimensional examples, and a fully 3D solution of the Boltzmann equation describing expansion of a gas into vacuum through a cylindrical tube.

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


A posteriori error analysis for a transient conjugate heat transfer problem We consider the accuracy of an operator decomposition finite element method for a transient conjugate heat transfer problem consisting of two materials coupled through a common boundary. We derive accurate a posteriori error estimates that account for the transfer of error between components of the operator decomposition method as well as the errors in solving the iterative system. We address a loss of order of convergence that results from the decomposition, and show that the order of convergence is limited by the accuracy of the transferred gradient information. We extend a boundary flux recovery method to transient problems and use it to regain the expected order of accuracy in an efficient manner. In addition, we use the a posteriori error estimates to adaptively compute the recovered boundary flux only within the domain of dependence for a quantity of 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 O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Imagery Mismatch Negativity in Musicians The present study investigated musical imagery in musicians and nonmusicians by means of magnetoencephalography (MEG). We used a new paradigm in which subjects had to continue familiar melodies in their mind and then judged if a further presented tone was a correct continuation of the melody. Incorrect tones elicited an imagery mismatch negativity (iMMN) in musicians but not in nonmusicians. This finding suggests that the MMN component can be based on an imagined instead of a sensory memory trace and that imagery of music is modulated by musical expertise.

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


Supporting sketch-based retrieval from a library of reusable behaviours Building the behaviour for non-player characters in a game is a complex collaborative task among AI designers and programmers. In this paper we present a visual authoring tool for game designers that supports behaviour reuse. We describe a visual editor, capable of storing, indexing, retrieving and reusing behaviours previously designed by AI programmers. One of the most notable features of our editor is its capability for sketch-based retrieval: searching in a repository for behaviours that are similar to the one the user is drawing, and making suggestions about how to complete it. As this process relies on graph behaviour comparison, in this paper, we describe different algorithms for graph comparison, and demonstrate, through empirical evaluation in a particular test domain, that we can provide structure-based similarity for graphs that preserves behaviour similarity and can be computed at reasonable cost. (C) 2012 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 O O O O O O O O O O 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 matching
behaviour authoring
game design
fsms
non-playing characters
ai authoring tools


Spectral and polarization analysis of geomagnetic pulsations data using a multitaper method Spectral and polarization parameters of geomagnetic pulsations are computed from geomagnetic data recorded at ground station, using multitaper and singular value decomposition (SVD) analysis. These techniques were adapted to provide appropriate polarization parameters of pulsations. The spectra are comparable to those obtained from classical methods, but the dynamic spectra of degree of polarization present more localized spectral information, allowing easier identification of polarized pulsation events mixed to noise, which are associated by coherent sources of MHD waves. The timefrequency polarization parameters of polarized pulsations show different signatures to regular and irregular pulsation events, and the multiwavelet polarization method is used to compare with multitaper. The regular pulsation events showed to be more continuous on time with a narrow spectral frequency band, while the irregular events showed to be more localized on time with a wide spectral frequency band. The dynamic analysis of multitaper method is indicated to characterize regular pulsations and the timefrequency analysis of multiwavelet method efficiently detects irregular pulsations. The continuous multiwavelet analysis of ellipticity and azimuth is useful in progressively monitoring the propagations of MHD waves in the magnetosphere, mainly in the irregular pulsations as observed on the magnetic storm of March 24, 1991.

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

multitaper
polarization analysis
geomagnetic pulsations