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921.
本文提出一种几何数据压缩的新算法,其基本思想是在已知物体网格边界的条件下,首先寻找边界的凹点,然后建立网格结点的特殊树结构,即横切面树,并将横切面树中相邻节点内网格结点之间的关系表示为链表(三角形条带),按契约数结构及链表(三角形条带)编码、存储帮传输网格结点的连接关系,这种算法不同于Gabriel Taubin算法,它具有对顶点坐标、属性坐标及三角形连接关系压缩无损等许多优点。 相似文献
922.
Esther Guerra Juan de Lara Paloma Díaz 《Journal of Visual Languages and Computing》2008,19(3):399-425
Ensuring model quality is a key success factor in many computer science areas, and becomes crucial in recent software engineering paradigms like the one proposed by model-driven software development. Tool support for measurements and redesigns becomes essential to help developers improve the quality of their models. However, developing such helper tools for the wide variety of (frequently domain specific) visual notations used by software engineers is a hard and repetitive task that does not take advantage from previous developments, thus being frequently forgotten.In this paper we present our approach for the visual specification of measurements and redesigns for Domain Specific Visual Languages (DSVLs). With this purpose, we introduce a novel DSVL called SLAMMER that contains generalisations of some of the more used types of internal product measurements and redesigns. The goal is to facilitate the task of defining measurements and redesigns for any DSVL, as well as the generation of tools from such specification reducing or eliminating the necessity of coding. We rely on the use of visual patterns for the specification of the relevant elements for each measurement and redesign type. In addition, SLAMMER allows the specification of redesigns either procedurally or by means of graph transformation rules. These redesigns can be triggered when the measurements reach a certain threshold.These concepts have been implemented in the meta-modelling tool AToM3. In this way, when a DSVL is designed, it is possible to specify measurements and redesigns that will become available in the final modelling environment generated for the language. As an example, we show a case study in the web modelling domain. 相似文献
923.
Agostinho de Medeiros Brito Junior Adri?o Duarte Dória Neto Jorge Dantas de Melo Luiz Marcos Garcia Goncalves 《Neural Networks, IEEE Transactions on》2008,19(6):1130-1140
In this paper, we propose a multiresolution approach for surface reconstruction from clouds of unorganized points representing an object surface in 3-D space. The proposed method uses a set of mesh operators and simple rules for selective mesh refinement, with a strategy based on Kohonen's self-organizing map (SOM). Basically, a self-adaptive scheme is used for iteratively moving vertices of an initial simple mesh in the direction of the set of points, ideally the object boundary. Successive refinement and motion of vertices are applied leading to a more detailed surface, in a multiresolution, iterative scheme. Reconstruction was experimented on with several point sets, including different shapes and sizes. Results show generated meshes very close to object final shapes. We include measures of performance and discuss robustness. 相似文献
924.
F. H. van Heesch M. A. Klompenhouwer G. de Haan 《Journal of the Society for Information Display》2008,16(10):1009-1019
Abstract— The spatio‐temporal aperture and sample rate of a video display determines both the static and dynamic resolution of the video signal that is rendered. The dynamic display characteristics like the visibility of large‐area flicker, motion judder, and motion blur can be derived from the frame rate and the temporal extent of the pixel aperture (i.e., the temporal aperture). For example, liquid‐crystal displays (LCDs) have an aperture that is relatively small in the spatial dimension and wide in the temporal domain. Consequently, moving objects displayed on an LCD suffer from motion blur. Especially in TV applications, the temporal dimension has a large impact on the overall picture quality. The temporal aperture, together with the frame rate, is shown to predict the amount of perceived large‐area flicker, motion judder, and motion blur and also the performance of motion‐blur reduction algorithms for LCDs. From this analysis it is further determined how to obtain the optimal temporal aperture of a television display, for which not only properties of the human visual system (HVS), but also the properties of the video signal have to be taken into account. 相似文献
925.
Marcel P. C. M. Krijn Siebe T. de Zwart Dick K. G. de Boer Oscar H. Willemsen Maarten Sluijter 《Journal of the Society for Information Display》2008,16(8):847-855
Abstract— An attractive concept for 3‐D displays is the one based on LCDs equipped with lenticular lenses. This enables autostereoscopic multiview 3‐D displays without a loss in brightness. A general issue in multiview 3‐D displays is their relatively low spatial resolution because the pixels are divided among the different views. To overcome this problem, we have developed switchable displays, using liquid‐crystal (LC) filled switchable lenticulars. In this way, it is possible to have a high‐brightness 3‐D display capable of fully exploiting the native 2‐D resolution of the underlying LCD. The feasibility of LC‐filled switchable lenticulars was shown in several applications. For applications in which it is advantageous to be able to display 3‐D and 2‐D content simultaneously, a 42‐in. locally switchable prototype having a matrix electrode structure was developed. These displays were realized using cylindrically shaped lenticular lenses in contact with LC. An alternative for these are lenticulars based on gradient‐index (GRIN) LC lenses. Preliminary results for such switchable GRIN lenses are presented as well. 相似文献
926.
The combined study of the literature about human resource management and the resource‐based view of the firm and organizational learning provides an analysis framework useful for understanding how strategic human resource management systems contribute to the creation and development of a sustained competitive advantage for the firm. This article has two major aims. First, it provides a conceptual framework linking simultaneously three theoretical blocks: (a) human resource management, (b) organizational learning and knowledge management, and (c) sustained competitive advantage. Second, the article builds a causal model and tests it with a sample of Spanish firms from the manufacturing industry using structural equation modeling (SEM). After the performance of a cluster analysis, a group of 72 learning firms is identified and used to test the model. Finally, major conclusions and implications for management are drawn and further avenues for research are suggested. © 2008 Wiley Periodicals, Inc. 相似文献
927.
Shintaro Okazaki Ph.D. Radoslav Skapa Ph.D. Ildefonso Grande Ph.D. 《Journal of Computer-Mediated Communication》2008,13(4):827-855
We adapt the technology acceptance model (TAM) to examine the factors influencing mobile gaming adoption among “global youth.” Our model replaces usefulness with convenience, incorporating visual appeal and escapism as antecedents of fun, and perceived novelty and economic value as antecedents of convenience. Questionnaire surveys were conducted in the U.S., Spain, and the Czech Republic, producing 432 usable responses. In the structural model assessment with the pooled sample, convenience exercises greater effects on attitude toward mobile games than fun, suggesting that the most important driver is probably the capability of being used flexibly at any time and in any place, rather than mere enjoyment. Tests of latent means suggest that most dimensions are perceived more strongly in the Czech Republic. 相似文献
928.
Herbert Van de Sompel Ryan Chute Patrick Hochstenbach 《International Journal on Digital Libraries》2008,9(2):83-100
The need to federate repositories emerges in two distinctive scenarios. In one scenario, scalability-related problems in the
operation of a repository reach a point beyond which continued service requires parallelization and hence federation of the
repository infrastructure. In the other scenario, multiple distributed repositories manage collections of interest to certain
communities or applications, and federation is an approach to present a unified perspective across these repositories. The
high-level, 3-Tier aDORe federation architecture can be used as a guideline to federate repositories in both cases. This paper
describes the architecture, consisting of core interfaces for federated repositories in Tier-1, two shared infrastructure
components in Tier-2, and a single-point of access to the federation in Tier-3. The paper also illustrates two large-scale
deployments of the aDORe federation architecture: the aDORe Archive repository (over 100,000,000 digital objects) at the Los
Alamos National Laboratory and the Ghent University Image Repository federation (multiple terabytes of image files). 相似文献
929.
Erick Corrêa da Silva Aristófanes Corrêa Silva Anselmo Cardoso de Paiva Rodolfo Acatauassu Nunes 《Pattern Analysis & Applications》2008,11(1):89-99
This paper analyzes the application of Moran’s index and Geary’s coefficient to the characterization of lung nodules as malignant
or benign in computerized tomography images. The characterization method is based on a process that verifies which combination
of measures, from the proposed measures, has been best able to discriminate between the benign and malignant nodules using
stepwise discriminant analysis. Then, a linear discriminant analysis procedure was performed using the selected features to
evaluate the ability of these in predicting the classification for each nodule. In order to verify this application we also
describe tests that were carried out using a sample of 36 nodules: 29 benign and 7 malignant. A leave-one-out procedure was
used to provide a less biased estimate of the linear discriminator’s performance. The two analyzed functions and its combinations
have provided above 90% of accuracy and a value area under receiver operation characteristic (ROC) curve above 0.85, that
indicates a promising potential to be used as nodules signature measures. The preliminary results of this approach are very
encouraging in characterizing nodules using the two functions presented.
相似文献
Rodolfo Acatauassu NunesEmail: |
930.
Implementing an enterprise system involves capturing all information necessary to make business processes work in an integrated fashion, and reflecting this integration in source code. Enterprise resource planning implementations should also exploit reuse of existing system elements. ERP tools typically work on top of a framework, using prefabricated modules to create customized variants of the system. Among the free and open source ERP systems, only ERP5 offers a comprehensive set of tools tailored to its framework that, together with other off-the-shelf tools, provide support for creating new modules and entire new systems. 相似文献