Path protection requires finding a working path and a protection path that are link disjoint. In this paper, we consider the dynamic lightpath protection problem in WDM mesh networks where a single risk factor may cau...
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Path protection requires finding a working path and a protection path that are link disjoint. In this paper, we consider the dynamic lightpath protection problem in WDM mesh networks under the wavelength continuity co...
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Due to its simplicity and scalability, the differentiated services (DiffServ) model is expected to be widely deployed across the Internet. For each DiffServ compliant router, the scheduling algorithm is critical in im...
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Due to its simplicity and scalability, the differentiated services (DiffServ) model is expected to be widely deployed across the Internet. For each DiffServ compliant router, the scheduling algorithm is critical in implementing per hop behaviors (PHBs), according to which packets are forwarded. In this paper, we propose the hierarchical DiffServ scheduling (HDS) algorithm to support DiffServ classes on input-queued switches. The proposed HDS algorithm features in a hierarchical scheduling scheme that consists of two levels of schedulers. One level is the central scheduler which is designed to maximize the switch throughput by computing a maximal size matching between input ports and output ports. The other level is formed by input port schedulers which provide differentiated services by serving cells belonging to different classes dynamically. Using such a hierarchical scheme, the implementation complexity and the amount of information needs to be transmitted between input ports and the central scheduler are dramatically reduced compared with existing maximal weight matching based DiffServ scheduling algorithms. The tradeoff of its slightly worse delay performance is acceptable.
Subdivision surfaces are rapidly gaining popularity in computer graphics, modeling, simulation and animation. Existing of subdivision algorithms is suffer from the lack of precise definition of the schemes with guaran...
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Subdivision surfaces are rapidly gaining popularity in computer graphics, modeling, simulation and animation. Existing of subdivision algorithms is suffer from the lack of precise definition of the schemes with guaranteed behavior for a sufficiently general type of control meshes, non-smoothness due to the existence of regular and non-regular face types during the subdivision process and incapability of optimizing mesh subdivision up to user-controlled criteria. This paper proposes a new algorithm for unifying surface types and optimizing the surface continuity consequently increases the smoothness of the generated mesh surface. Comparisons with existing techniques are included;advantages of our proposed technique over previous algorithms are examined. Our approach is supported by discussions and illustrations of some experimental results.
Let B be a set of n unit balls in 3. We show that the combinatorial complexity of the space of lines in 3 that avoid all the balls of B is O(n3+Ε), for any Ε > 0. This result has connections to problems in visibi...
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Let B be a set of n unit balls in 3. We show that the combinatorial complexity of the space of lines in 3 that avoid all the balls of B is O(n3+Ε), for any Ε > 0. This result has connections to problems in visibility, ray shooting, motion planning and geometric optimization.
To make up for the drawbacks of the rough set model on general relation, a majority inclusion relation is defined and an error parameter α is introduced in order to give a variable precision rough set model based on ...
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ISBN:
(纸本)0780384032
To make up for the drawbacks of the rough set model on general relation, a majority inclusion relation is defined and an error parameter α is introduced in order to give a variable precision rough set model based on general relation. In our rough set model, if α satisfies some conditions, then the model will degenerates the basic rough set model which was first introduced by Z. Pawlak or degenerate the graded rough set model. What follows that model proposed in this paper is an extension of the classical basic rough set based on general relation and graded rough set model. After introducing the error parameter α, more useful information and data are collected and mined. Thus, the drawbacks, which lose more useful information for demanding the inclusion of the absolutely precision in the classical basic rough set model, are overcome.
A system is presented for automatic classification of the atmosphere in motion pictures scenes. This classification is based solely on the extraction of approximate illumination information from single frames. By usin...
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A system is presented for automatic classification of the atmosphere in motion pictures scenes. This classification is based solely on the extraction of approximate illumination information from single frames. By using well defined film grammar rules regarding scene lighting, it generates high level semantic descriptors for frames and scenes. These illumination descriptors could be further combined with other descriptors like motion and sound, to generate a complete automatic semantic analysis system of video media.
We present a method for space-time completion of large space-time "holes" in video sequences of complex dynamic scenes. The missing portions are filled-in by sampling spatio-temporal patches from the availab...
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We present a method for space-time completion of large space-time "holes" in video sequences of complex dynamic scenes. The missing portions are filled-in by sampling spatio-temporal patches from the available parts of the video, while enforcing global spatio-temporal consistency between all patches in and around the hole. This is obtained by posing the task of video completion and synthesis as a global optimization problem with a well-defined objective function. The consistent completion of static scene parts simultaneously with dynamic behaviors leads to realistic looking video sequences. Space-time video completion is useful for a variety of tasks, including, but not limited to: (i) Sophisticated video removal (of undesired static or dynamic objects) by completing the appropriate static or dynamic background information, (ii) Correction of missing/corrupted video frames in old movies, and (iii) Synthesis of new video frames to add a visual story, modify it, or generate a new one. Some examples of these are shown in the paper.
The current best-effort service model used on the Internet treats all requests uniformly, both in the network and at the application level. However, sometimes it is desirable to provide different classes or levels of ...
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The current best-effort service model used on the Internet treats all requests uniformly, both in the network and at the application level. However, sometimes it is desirable to provide different classes or levels of service in order to satisfy the needs of different users and applications. In this paper, we propose an architecture for the provision of differentiated services at the web server level. The architecture is verified by means of a simulation model and real web server traces are used as workload. Two priority-based algorithms are implemented in the architecture aiming at service differentiation. The adaptive algorithm, an innovative solution at the application domain, allows the tuning of the priority level provided and determines how strict the use of priorities will be. The system can then adapt itself to various workloads, an essential feature in a highly dynamic environment such as the Web.
A geometric graph is a simple graph G = (V, E) with an embedding of the set V in the plane such that the points that represent V are in general position. A geometric graph is said to be k-locally Delaunay (or a D k-gr...
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A geometric graph is a simple graph G = (V, E) with an embedding of the set V in the plane such that the points that represent V are in general position. A geometric graph is said to be k-locally Delaunay (or a D k-graph) if for each edge (u, v) ∈ E there is a (Euclidean) disc d that contains u and v but no other vertex of G that is within k hops from u or v. The study of these graphs was recently motivated by topology control for wireless networks. We obtain the following results: (i) We prove that if G is a Di-graph on n vertices, then it has O(n3/2) edges. (ii) We show that for any n there exist D1-graphs with n vertices and Ω(n4/3) edges. (iii) We prove that if G is a D 2-graph on n vertices, then it has O(n) edges. This bound is worst-case asymptotically tight. As an application of the first result, we show that: (iv) The maximum size of a family of pairwise non-overlapping lenses in an arrangement of n unit circles in the plane is O(n3/2). The first two results improve the best previously known upper and lower bounds of O(n 5/3) and Ω(n) respectively (see [6]). The third result improves the best previously known upper bound of O(n log n). Finally, our last result improves the best previously known upper bound (for the more general case of not necessarily unit circles) of O(n3/2k(n)) (see [1]), where k(n) = (log n)O(α2(n)) and where α(n) is the extremely slowly growing inverse Ackermann's function.
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