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981.
Lars Grunske Kirsten Winter Nisansala Yatapanage 《Journal of Visual Languages and Computing》2008,19(3):343-379
Diagrammatic visual languages can increase the ability of engineers to model and understand complex systems. However, to effectively use visual models, the syntax and semantics of these languages should be defined precisely. Since most diagrammatic visual models that are currently used to specify systems can be described as (directed) typed graphs, graph grammars have been identified as a suitable formalism to describe the abstract syntax of visual modeling languages. In this article, we investigate how advanced graph-transformation techniques, such as conditional, structure-generic and type-generic graph-transformation rules, can help to improve and simplify the specification of the abstract syntax of a visual modeling language. To demonstrate the practicability of an approach that unifies these advanced graph-transformation techniques, we define the abstract syntax of behavior trees (BTs), a graphical specification language for functional requirements. Additionally, we provide a translational semantics of BTs by formalizing a translation scheme to the input language of the SAL model checking tool for each of the graph-transformation rules. 相似文献
982.
Meyer-Spradow J Stegger L Döring C Ropinski T Hinrichs K 《IEEE transactions on visualization and computer graphics》2008,14(6):1499-1506
Myocardial perfusion imaging with single photon emission computed tomography (SPECT) is an established method for the detection and evaluation of coronary artery disease (CAD). State-of-the-art SPECT scanners yield a large number of regional parameters of the left-ventricular myocardium (e.g., blood supply at rest and during stress, wall thickness, and wall thickening during heart contraction) that all need to be assessed by the physician. Today, the individual parameters of this multivariate data set are displayed as stacks of 2D slices, bull's eye plots, or, more recently, surfaces in 3D, which depict the left-ventricular wall. In all these visualizations, the data sets are displayed side-by-side rather than in an integrated manner, such that the multivariate data have to be examined sequentially and need to be fused mentally. This is time consuming and error-prone. In this paper we present an interactive 3D glyph visualization, which enables an effective integrated visualization of the multivariate data. Results from semiotic theory are used to optimize the mapping of different variables to glyph properties. This facilitates an improved perception of important information and thus an accelerated diagnosis. The 3D glyphs are linked to the established 2D views, which permit a more detailed inspection, and to relevant meta-information such as known stenoses of coronary vessels supplying the myocardial region. Our method has demonstrated its potential for clinical routine use in real application scenarios assessed by nuclear physicians. 相似文献
983.
Linsen L Van Long T Rosenthal P Rosswog S 《IEEE transactions on visualization and computer graphics》2008,14(6):1483-1490
Data sets resulting from physical simulations typically contain a multitude of physical variables. It is, therefore, desirable that visualization methods take into account the entire multi-field volume data rather than concentrating on one variable. We present a visualization approach based on surface extraction from multi-field particle volume data. The surfaces segment the data with respect to the underlying multi-variate function. Decisions on segmentation properties are based on the analysis of the multi-dimensional feature space. The feature space exploration is performed by an automated multi-dimensional hierarchical clustering method, whose resulting density clusters are shown in the form of density level sets in a 3D star coordinate layout. In the star coordinate layout, the user can select clusters of interest. A selected cluster in feature space corresponds to a segmenting surface in object space. Based on the segmentation property induced by the cluster membership, we extract a surface from the volume data. Our driving applications are Smoothed Particle Hydrodynamics (SPH) simulations, where each particle carries multiple properties. The data sets are given in the form of unstructured point-based volume data. We directly extract our surfaces from such data without prior resampling or grid generation. The surface extraction computes individual points on the surface, which is supported by an efficient neighborhood computation. The extracted surface points are rendered using point-based rendering operations. Our approach combines methods in scientific visualization for object-space operations with methods in information visualization for feature-space operations. 相似文献
984.
Smooth surface extraction using partial differential equations (PDEs) is a well-known and widely used technique for visualizing volume data. Existing approaches operate on gridded data and mainly on regular structured grids. When considering unstructured point-based volume data where sample points do not form regular patterns nor are they connected in any form, one would typically resample the data over a grid prior to applying the known PDE-based methods. We propose an approach that directly extracts smooth surfaces from unstructured point-based volume data without prior resampling or mesh generation. When operating on unstructured data one needs to quickly derive neighborhood information. The respective information is retrieved by partitioning the 3D domain into cells using a kd-tree and operating on its cells. We exploit neighborhood information to estimate gradients and mean curvature at every sample point using a four-dimensional least-squares fitting approach. Gradients and mean curvature are required for applying the chosen PDE-based method that combines hyperbolic advection to an isovalue of a given scalar field and mean curvature flow. Since we are using an explicit time-integration scheme, time steps and neighbor locations are bounded to ensure convergence of the process. To avoid small global time steps, we use asynchronous local integration. We extract the surface by successively fitting a smooth auxiliary function to the data set. This auxiliary function is initialized as a signed distance function. For each sample and for every time step we compute the respective gradient, the mean curvature, and a stable time step. With these informations the auxiliary function is manipulated using an explicit Euler time integration. The process successively continues with the next sample point in time. If the norm of the auxiliary function gradient in a sample exceeds a given threshold at some time, the auxiliary function is reinitialized to a signed distance function. After convergence of the evolution, the resulting smooth surface is obtained by extracting the zero isosurface from the auxiliary function using direct isosurface extraction from unstructured point-based volume data and rendering the extracted surface using point-based rendering methods. 相似文献
985.
Lars M. Kristensen Peter Mechlenborg Lin Zhang Brice Mitchell Guy E. Gallasch 《International Journal on Software Tools for Technology Transfer (STTT)》2008,10(1):5-14
This paper shows how a formal method in the form of Coloured Petri Nets (CPNs) and the supporting CPN Tools have been used
in the development of the Course of Action Scheduling Tool (COAST). The aim of COAST is to support human planners in the specification
and scheduling of tasks in a Course of Action. CPNs have been used to develop a formal model of the task execution framework
underlying COAST. The CPN model has been extracted in executable form from CPN Tools and embedded directly into COAST, thereby
automatically bridging the gap between the formal specification and its implementation. The scheduling capabilities of COAST
are based on state space exploration of the embedded CPN model. Planners interact with COAST using a domain-specific graphical
user interface (GUI) that hides the embedded CPN model and analysis algorithms. This means that COAST is based on a rigorous
semantical model, but the use of formal methods is transparent to the users. Trials of operational planning using COAST have
been conducted within the Australian Defence Force.
The work of Lin Zhang was done while he was with the Command and Control Division of the Australian Defence Science and Technology
Organisation. 相似文献
986.
Lars Kristiansen 《Theory of Computing Systems》2008,43(3-4):516-541
We introduce two hierarchies of unknown ordinal height. The hierarchies are induced by natural fragments of a calculus based on finite types and Gödel’s T, and all the classes in the hierarchies are uniformly defined without referring to explicit bounds. Deterministic complexity classes like logspace, p, pspace, linspace and exp are captured by the hierarchies. Typical subrecursive classes are also captured, e.g. the small relational Grzegorczyk classes ? * 0 , ? * 1 and ? * 2 . 相似文献
987.
Yoanna Choleva Mikkel Nrholm Susanne Pedersen Peter Mouritzen Poul E. Hiby Alex. T. Nielsen Sren Mller Mogens H. Jakobsen Lars Kongsbak 《Journal of The Association for Laboratory Automation》2001,6(4):92
Locked Nucleic Acid's or LNA are a new class of bicyclic DNA analogues that have a high affinity and specificity towards complementary nucleic acids. LNA containing oligonucleotides were used to develop a multiplex SNP genotyping assay based entirely on hybridization between capture probe and target. The approach incorporates a polymer microarray platform, photochemistry for immobilization of oligonucleotides onto microarrays, and a dedicated software tool to aid primer and capture probe design for highly multiplex genotyping. Furthermore, these technologies are combined in an integrated microfluidics platform for simple, highly multiplex and robust SNP genotyping. 相似文献
988.
As computers are increasingly woven into the fabric of everyday life, interaction design may have to change – from creating
only fast and efficient tools to be used during a limited time in specific situations, to creating technology that surrounds
us and therefore is a part of our activities for long periods of time. We present slow technology: a design agenda for technology aimed at reflection and moments of mental rest rather than efficiency in performance. The
aim of this paper is to develop a design philosophy for slow technology, to discuss general design principles and to revisit
some basic issues in interaction design from a more philosophical point of view. We discuss examples of soniture and informative art as instances of slow technology and as examples of how the design principles can be applied in practice. 相似文献
989.
Hejnaes Kim Ry; Bayne Stephen; Norskov Leif; Holmegaard Hans; Sorensen H.H.; Thomsen Johannes; Schaffer Lauge; Wollmer Axel; Skriver Lars 《Protein engineering, design & selection : PEDS》1992,5(8):797-806
Denatured and reduced N-terminal extended insulin-like growthfactor-1 (AE-IGF-1) was purified from Escherichia coli extractsand subjected to in vitro folding. The renaturation processwas shown to be a function of the redox potential of the solution.Folding by different methods had no significant effect on therenaturation. A maximal yield of 60% (w/w)was obtained. Thefolded AE-IGF-1 was enzymatically converted to IGF-1. The majorby-product (20% w/w) was identified as scrambled IGF-1. Enzymaticdigestion at alkaline and acidic pH suggested two possible disulphidebond arrangements: (i) Cys6Cys47, Cys18Cys61,Cys48Cys52; or (if) Cys6Cys52, Cysl8Cys61,Cys47 and Cys48 being in their reduced forms. Energy minimizationand molecular modelling suggested that the scrambled IGF-1,having reduced cysteines at positions 47 and 48, was the energeticallymost stable conformation of the two. 相似文献
990.
Mantouvalou I Malzer W Schaumann I Lühl L Dargel R Vogt C Kanngiesser B 《Analytical chemistry》2008,80(3):819-826
The recently developed 3D micro X-ray fluorescence spectroscopy (3D Micro-XRF) enables three-dimensional resolved, nondestructive investigation of elemental distribution in samples in the micrometer regime. Establishing a reliable quantification procedure is the precondition to render this spectroscopic method into a true analytical tool. One prominent field of application is the investigation of stratified material. A procedure for the quantitative reconstruction of the composition of stratified material by means of 3D Micro-XRF is proposed and validated. With the procedure, it is now possible to determine nondestructively the chemical composition and the thickness of layers. As no adequate stratified reference samples were available for validation, stratified reference material has been developed that is appropriate for 3D Micro-XRF or other depth-sensitive X-ray techniques. 相似文献