Interactions between a virtual actor and its virtual environment involve many aspects. An important one is hands interactions. In a virtual scene depicting everyday life, the actor will need to grasp and hold objects,...
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In this paper we extend the concept of Voronoi diagrams to parameterized surfaces where distance between two points is defined as infimum over the lengths of surface paths connecting these points. We present a method ...
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In this paper we extend the concept of Voronoi diagrams to parameterized surfaces where distance between two points is defined as infimum over the lengths of surface paths connecting these points. We present a method to compute Voronoi diagrams on these surfaces.
We consider the extremal problem to determine the maximal number N(m, k, r) of columns of a 0-1 matrix with m rows and at most r ones in each column such that each k columns are linearly independent modulo 2. For fixe...
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We consider the extremal problem to determine the maximal number N(m, k, r) of columns of a 0-1 matrix with m rows and at most r ones in each column such that each k columns are linearly independent modulo 2. For fixed integers k ≥ 1 and r ≥ 1, we shall prove thep robabilistic lower bound N(m, k, r) = Ω(mkr/2(k-1)) for k a power of 2, we prove the upper bound N(m, k, r) = O(m[kr/(k-1)]/2) which matches the lower bound for infinitely many values of r. We give some explicit constructions.
作者：
L. Miguel EncarnaçãoUniversity of Tübingen
Wilhelm-Schickard-Institute of Computer Science Interactive Graphics Systems Lab (WSI/GRIS) Auf der Morgenstelle 10 C9 D-72076 Tübingen Germany
This case study analyses how the adoption of material requirement planning (MRP) at Alenia Aircraft has brought about organizational and logistic changes in the firm's supply chain. The impact of the MRP system on...
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This case study analyses how the adoption of material requirement planning (MRP) at Alenia Aircraft has brought about organizational and logistic changes in the firm's supply chain. The impact of the MRP system on the supply chain is investigated by analysing the relationship between Alenia Aircraft and the firm Alfa, one of its more significant subcontractors. The case study highlights the current trends within Alenia Aircraft's supply chain. A tiering of the subcontracting firms is taking place through a selection process, leading some traditional subcontractors to become main subcontractors while only some of them become main verticalized subcontractors . In this selection and tiering process of the supply chain, a crucial role is played by the subcontractors' managerial, organizational and logistic capabilities.
The draft international standard ITU-T H.263 is closely related to the well known and widely used ITU-T Recommendation H.261. However, H.263 does provide the same subjective image quality at less than half the bit-rat...
The draft international standard ITU-T H.263 is closely related to the well known and widely used ITU-T Recommendation H.261. However, H.263 does provide the same subjective image quality at less than half the bit-rate. In this paper we investigate to what extend single enhancements of H.263 contribute to this performance gain, and consider the trade-off quality vs. complexity. Based on typical test sequences, H.263 with its various modes is compared to H.261 on the basis of rate distortion curves at bit-rates up to 128 kbps. At 64 kbps, the performance gain of H.263 in its default mode compared to H.261 is approximately 2 dB. This improvement is achieved with only little increase of complexity, and is mainly due to more accurate motion compensation with half-pel accuracy. Considering the trade-off quality vs. complexity, the combination of the optional coding-modes "Advanced prediction mode" and "PB-frames mode" is a good compromise, resulting in an additional performance gain of 1.5 dB PSNR at 64 kbps. The "Syntax-based arithmetic coding mode" on the other hand, offers only a very small performance gain (0.1 dB at 64 kbps) for its increased computational complexity. Results from profiling an H.263 software codec are presented in order to support complexity considerations of the optional coding-modes.
This article describes the effort to join two different approaches for the development of the proactive network management. The first approach was developed in the Laboratory of Network and Management, at Federal Univ...
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This article describes the effort to join two different approaches for the development of the proactive network management. The first approach was developed in the Laboratory of Network and Management, at Federal University of Santa Catarina, which uses remote monitoring and simulation tools. The second one, was developed in the National Supercomputing Center, which handles the problem with artificial intelligence and SunNet Manager's agents usage. The new concept of proactive network management aims at identifying the existing troubles in advance of any performance degradation, as well as providing support for future decision-making actions. The goal of this work is to adapt a complete proactive environment which will be used to explore the remote monitors and simulation tools to identify the symptoms of proactive management problems; and specially to recognize the problem using artificial intelligence techniques and to take proactive actions to solve it, configuring a proactive management application for the prevention of problems in computer networks.
A prototype concurrent engineering tool has been developed for the preliminary design of composite topside structures for modern navy warships. This tool, named GELS for the Concurrent Engineering of Layered Structure...
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A prototype concurrent engineering tool has been developed for the preliminary design of composite topside structures for modern navy warships. This tool, named GELS for the Concurrent Engineering of Layered Structures, provides designers with an immediate assessment of the impacts of their decisions on several disciplines which are important to the performance of a modern naval topside structure, including electromagnetic interference effects (EMI), radar cross section (RCS), structural integrity, cost, and weight. Preliminary analysis modules in each of these disciplines are integrated to operate from a common set of design variables and a common materials database. Performance in each discipline and an overall fitness function for the concept are then evaluated. A graphical user interface (GUI) is used to define requirements and to display the results from the technical analysis modules. Optimization techniques, including feasible sequential quadratic programming (FSQP) and exhaustive search are used to modify the design variables to satisfy all requirements simultaneously. The development of this tool, the technical modules, and their integration are discussed noting the decisions and compromises required to develop and integrate the modules into a prototype conceptual design tool.
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