Surface mesh regeneration considering curvatures

This work describes an automatic algorithm for unstructured mesh regeneration on arbitrarily shaped three-dimensional surfaces. The arbitrary surface may be: a triangulated mesh, a set of points, or an analytical surface (such as a collection of NURBS patches). To be generic, the algorithm works directly in Cartesian coordinates, as opposed to generating the mesh in parametric space, which might not be available in all the cases. In addition, the algorithm requires the implementation of three generic functions that abstractly represent the supporting surface. The first, given a point location, returns the desired characteristic size of a triangular element at this position. The second method, given the current edge in the boundary-contraction algorithm, locates the ideal apex point that forms a triangle with this edge. And the third method, given a point in space and a projection direction, returns the closest point on the geometrical supporting surface. This work also describes the implementation of these three methods to re-mesh an existing triangulated mesh that might present regions of high curvature. In this implementation, the only information about the surface geometry is a set of triangles. In order to test the efficiency of the proposed algorithm of surface mesh generation and implementation of the three abstract methods, results of performance and quality of generated triangular element examples are presented.     

Survey on using constraints in data mining

This paper provides an overview of the current state-of-the-art on using constraints in knowledge discovery and data mining. The use of constraints in a data mining task requires specific definition and satisfaction tools during knowledge extraction. This survey proposes three groups of studies based on classification, clustering and pattern mining, whether the constraints are on the data, the models or the measures, respectively. We consider the distinctions between hard and soft constraint satisfaction, and between the knowledge extraction phases where constraints are considered. In addition to discussing how constraints can be used in data mining, we show how constraint-based languages can be used throughout the data mining process.     

Mobile Agent Coordination for Distributed Network Management

Mobile agents are a promising technology to face the problems raised by the increasing complexity and size of today's networks. In particular, in the area of network management, mobile agents can lead to a fully distributed paradigm to overcome the limits of traditional centralized approaches. A basic requirement for the management of a complex network is the definition of high-level and flexible models to coordinate the accesses to the resources—data and services—provided by the network nodes. On this basis, this paper describes the MARS coordination architecture for mobile agents. MARS is based on the definition of programmable tuple spaces associated with the network nodes: mobile agents can access the local resources and services via the tuple space, thus adopting a standard and high-level interface. The network administrator—via mobile agents—can dynamically program the behavior of the tuple space in reaction to the agents' access to the tuple space, thus leading to a flexible network model. Several examples show the effectiveness of the MARS approach in supporting network management activities.     

Mixture of KL subspaces for relevance feedback

Relevance feedback has recently emerged as a solution to the problem of improving the retrieval performance of an image retrieval system based on low-level information such as color, texture and shape features. Most of the relevance feedback approaches limit the utilization of the user’s feedback to a single search session, performing a short-term learning. In this paper we present a novel approach for short and long term learning, based on the definition of an adaptive similarity metric and of a high level representation of the images. For short-term learning, the relevant and non-relevant information given by the user during the feedback process is employed to create a positive and a negative subspace of the feature space. For long-term learning, the feedback history of all the users is exploited to create and update a representation of the images which is adopted for improving retrieval performance and progressively reducing the semantic gap between low-level features and high-level semantic concepts. The experimental results prove that the proposed method outperforms many other state of art methods in the short-term learning, and demonstrate the efficacy of the representation adopted for the long-term learning.

Testing Planning Domains (without Model Checkers)

We address the problem of verifying planning domains as used in model-based planning, for example in space missions. We propose a methodology for testing flight rules of planning domains which is self-contained, in the sense that flight rules are verified using a planner and no external tools are required. We review and analyse coverage conditions for requirements-based testing, and we reason in detail on "Unique First Cause" (UFC) coverage for test suites. We characterise flight rules using patterns, encoded using LTL, and we provide UFC coverage for them. We then present a translation of LTL formulae into planning goals, and illustrate our approach on a case study.     

ELNES at magic angle conditions

If one needs to cancel the effects of the anisotropy of the sample in a EELS experiment in the TEM, a particular couple of values for the collection and convergence angle must be used, called magic angle conditions (MAC). Recent developments in the theory have shown that a full relativistic treatment is mandatory to correctly describe this effect and that the MAC are strongly dependent on the acceleration voltage. We show how the analytical formula can be derived and give the exact analytical solution for the MAC which can then be easily applied to every practical case. We show the consequences of the energy dependence of the magic angle and that the parallelity of the beam will be the limiting factor for high acceleration voltages while for low acceleration voltages the contribution coming from Bragg spots may make it impossible to reach MAC.     

Ecclesiastes effects

The reward system in science involves several psychosocial processes that can be named after books in theBible: Merton proposed the Matthew Effect andTurner andChubin offered the Ecclesiastes Hypothesis, based on relevant biblical passages. This article identifies several other bibliometric phenomena described inEcclesiastes, including an explanation of why there is a multiplication of specializations in disciplines with growing literatures.     

Using Similarity Analyses to Scale Out Research Findings Across Andean Watershed Basins

Abstract

Strategic research in agriculture and natural resources carried out by international research centers is deemed a public good and should, sooner or later, be put into the hands of development, governmental and non-governmental organizations. However, this research is usually done at specific pilot sites; there is a greater need to know how representative those sites are in relation to the diversity of contexts in other locations. Such is the case with the Challenge Program on Water and Food (CPWF), a global initiative in water research promoted by the Consultative Group on International Agricultural Research (CGIAR), which is developing and implementing strategic research in nine basins located in the tropics of Africa, Asia and South America. Given that resources are not available to collect data from the whole of the region, pilot sites are needed. It is hoped that research outputs obtained in the selected pilot sites can be the basis for scaling out solutions to similar situations in neighbouring or adjacent areas in same or different basins.

In order to contribute to the scaling-out process, different classification methodologies were applied to determine how specific watershed basins are representative of larger areas. The Andean eco-region served as a case study but the methods can easily be applied in other regions. The spatial diversity of biophysical and social conditions across the Andes requires careful site selection. Two methods, a combination of Weight of Evidence (WofE) and Logistic Regression (LR) methods and Fast Cluster analysis, were used to determine the similarity of selected sites with those excluded. A 1-km study resolution covering most of the Andes eco-region included annual rainfall, elevation, length of growing period, land cover, roads and population density as the key variables. Results showed complementarities between the two methods in presenting a probability surface of similarity across the Andes and a clustering of similar sites inside and outside the pilot basins. The output information forms a strong basis for devising plans to scale out research findings from the pilot basins to the whole region.     

Schnelle Bestimmung von Furfurol und Hydroxymethylfurfurol in alkoholischen Getr?nken mit Hilfe der Umkehrphasen-Chromatographie

Zusammenfassung Furfurol und Hydroxymethylfurfurol können leicht mit Hilfe der Umkehrphasen-Chromatographie in Alkoholika bestimmt werden. Eine Probenvorbereitung ist nicht notwendig. Die beiden Aldehyde werden UV-spektrometrisch erfaßt, die absolute Nachweisgrenze bei Routinearbeiten beträgt 4–7 mg/100 l reinen Alkohol (entsprechend 0,01–0,03 mg/l im Getränk) und kann für Spurenbestimmungen auf 0,002–0,001 mg/l durch Injektion von größeren Probenvolumen erniedrigt werden. Die Peakhöhen der beiden Furfuroie sind im Bereich von 0,25–3 mg/l Getränk linear von der Konzentration abhängig. Die Gesamtanalyse dauert etwa 12 min. Mit der beschriebenen Methode werden brasilianischer Zukkerrohrschnaps (Cachaça) Bowie eine Reihe in Deutschland käuflicher Alkoholika untersucht.

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Rapid determination of furfural and hydroxymethylfurfural in alcoholic beverages by reverse-phase-chromatographyComparative investigations on the content of furfurals in Brazilian Cachaça and other alcoholic liquors

Summary Furfural and Hydroxymethylfurfural can easily be determined in alcoholic beverages by means of reverse phase chromatography. A special sample preparation is not necessary. The aldehydes are detected by UV-spectrometry, the absolute detection limit in routine work is 4–7 mg/100 liters of pure ethanol (corresponding to 0.016–0.03 mg/l beverage) and can be extended down to 0.002–0.001 mg/l when injecting higher volumes for trace analysis. In the range of 0.25–3 mg/l linear relationship is obtained between peak hight and concentration. The complete assay procedure takes about 12 min. A series of Brazilian Cachaça samples and German commercial liquors were investigated with the here described method.

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Sumário Os autores apresentam um método de determinação de Furfural e Hidroxi-metilfurfural em cachaça e outras bebidas alcoolicas, Cromatografia em alta pressão com colunas de fase reversa (C₈; 5 m; 250 × 4 mm; CH₃CN/H₂O 5/95 como eluente) permite a separação e determinaçã sem pre-tratamento das amostras em 10–12 minutos. A sensibilidade da determinação em UV (254 nm) è 4–7 mg/100 L álcool puro (0.01–0.03 mg/L na bebida respectivamente). Usando um volume maior de injecção, o limite se pode abaixar até 0.002–0.001 mg/L bebida. A altura dos picos é proporçional à concentração entre 0.25–3 mg/L bebida. As cachaças investigadas possuem geralmente um conteúdo de Furfural e de Hidroxi-metilfurfural menor do que suposto e determinato pelo método de anilina recomendado pelo governo (determinação não específica).

     

γ-Radiolysis of Polyynes in Heptane

The polyynes in heptane solution were γ-radiolyzed at a total dose of 150, 300 and 600 kGy. After radiolysis the products were analyzed by electronic absorption spectroscopy, by HPLC (liquid chromatography) and by FT-IR spectroscopy. Even at 150 kGy the polyynes disappear completely from the solution and the chromatographic analysis shows that the acetylenic chains undergo fragmentation, addition and crosslinking reactions with other chains and with solvent. The oxidative interference from air has been detected by FT-IR.