Delay-tolerant networking (DTN) is an architecture to enable data communications between isolated or remote regions, where long delays and intermittent connectivity can be tolerated. An emerging class of DTN, called v...
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Delay-tolerant networking (DTN) is an architecture to enable data communications between isolated or remote regions, where long delays and intermittent connectivity can be tolerated. An emerging class of DTN, called vehicular DTNs (VDTN), exploits transportation systems as the transport layer to transfer data. In these networks, vehicles (e.g., busses, boats, trains) act as mobile nodes and carry data messages around. Mobile nodes can exchange data messages using devices called relay nodes. Relay nodes, placed in strategic positions along vehicle routes, have the capability to download, store, and upload the data messages from/to the mobile nodes. An important issue in VDTN is the optimal placement of the relay nodes such that delay-tolerant connectivity in VDTN is ensured at minimum cost. In this paper we show that the problem of optimal relay node placement is an NP-hard problem. Other contributions of this paper are the formulation of the relay node placement problem using ILP and the proposal of heuristic algorithms solving the optimization problem. Using simulation results, we compare the performance of each algorithm under different network constraints, such as node storage capability and network topology.
Feature-based flow visualization is naturally dependent on feature extraction. To extract flow features, often higher-order properties of the flow data are used such as the Jacobian or curvature properties, implicitly...
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A new robust watermarking 3D mesh model algorithm is presented in this paper. We embed two different watermarks into a 3D mesh. One of the two watermarks is based on feature information and another is embedded by Niel...
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A new robust watermarking 3D mesh model algorithm is presented in this paper. We embed two different watermarks into a 3D mesh. One of the two watermarks is based on feature information and another is embedded by Nielson norm. The two watermarks do not disturb each other. Since the algorithm is blind, it does not need the original model during extraction. The algorithm is applied to many mesh models. These experiments show that the watermarking scheme not only can keep original mesh feature information but also can resist some attacks, such as affine transformation, noising and cropping.
This paper introduces a network architecture called Vehicular Wireless Burst Switching (VWBS). The main objective of this architecture is to provide low-cost connectivity solution for isolated and dispersed regions wi...
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This paper introduces a network architecture called Vehicular Wireless Burst Switching (VWBS). The main objective of this architecture is to provide low-cost connectivity solution for isolated and dispersed regions with no networks infrastructure. The proposed architecture is based on the concept of Delay Tolerant Networks (DTN) and can be applied to various scenarios, including rapid deployment of emergency communication systems when all communication links have failed. In this paper, we present an overview of VWBS networks and show how their performance, in terms of average packet delays, can be improved using store-and-forward devices called relay nodes. Furthermore, we introduce several heuristic algorithms, which can be used to place minimum number of relay nodes. Through computer simulations, we compare the performance of the algorithms and their tradeoffs. We conclude our work by examining possible open research issues in VWBS.
As companies continue to embrace PLM practices to improve business operations, the ability to create and communicate 3D part and assembly representations throughout the enterprise is becoming increasingly important. C...
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As companies continue to embrace PLM practices to improve business operations, the ability to create and communicate 3D part and assembly representations throughout the enterprise is becoming increasingly important. Companies that design and produce particularly large artifacts, whether in terms of geometry scale or in terms of object complexity, experience problems of portability and scalability when using vendor-supported "standard" file formats. This presentation outlines a project, conducted in conjunction with a large aerospace firm, which examined the conversion, loading, and transportation of such files across a network. The project also examined user interaction with 3DXML files as compared to CGR files, within CATIA. A discussion of project activities, issues encountered, and resulting recommendations is included.
Incremental subspace methods have proven to enable efficient training if large amounts of training data have to be processed or if not all data is available in advance. In this paper we focus on incremental LDA learni...
ISBN:
(纸本)1901725340
Incremental subspace methods have proven to enable efficient training if large amounts of training data have to be processed or if not all data is available in advance. In this paper we focus on incremental LDA learning which provides good classification results while it assures a compact data representation. In contrast to existing incremental LDA methods we additionally consider reconstructive information when incrementally building the LDA subspace. Hence, we get a more flexible representation that is capable to adapt to new data. Moreover, this allows to add new instances to existing classes as well as to add new classes. The experimental results show that the proposed approach outperforms other incremental LDA methods even approaching classification results obtained by batch learning.
We present a new cellular automata model for one-lane traffic flow. In this model, we consider the driver prejudgment according to the state of the leading car. We also consider that the vehicle deceleration capabilit...
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We present a new cellular automata model for one-lane traffic flow. In this model, we consider the driver prejudgment according to the state of the leading car. We also consider that the vehicle deceleration capability is finite and the braking distance of the high-speed running cars cannot be ignored, which is not considered in most models. Furthermore, comfortable driving is considered, too. Using computer simulations we obtain some basic qualitative results and the fundamental diagram of the proposed model. In comparison with the known models, we find that the fundamental diagram of the proposed model is more realistic than that of the known models.
We describe a method for computing an implicit function that represents a surface by its zero level set, given a set of points scattered over the surface and associated with surface normal vectors. This implicit funct...
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We present a novel rendering algorithm that analyses the ray profiles along the line of sight. The profiles are subdivided according to encountered peaks and valleys at so called transition points. The sensitivity of ...
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ISBN:
(纸本)1568813376
We present a novel rendering algorithm that analyses the ray profiles along the line of sight. The profiles are subdivided according to encountered peaks and valleys at so called transition points. The sensitivity of these transition points is calibrated via two thresholds. The slope threshold is based on the magnitude of a peak following a valley, while the peeling threshold measures the depth of the transition point relative to the neighboring rays. This technique separates the dataset into a number of feature layers. The user can scroll through the layers inspecting various features from the current view position. While our technique has been inspired by opacity peeling approach, we demonstrate that we can reveal detectable features even in the third and forth layers for both CT and MRI datasets.
Sketching communicates ideas rapidly through approximate visual images with low overhead (pencil and paper), no need for precision or specialized knowledge, and ease of low-level correction and revision. In contrast, ...
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Sketching communicates ideas rapidly through approximate visual images with low overhead (pencil and paper), no need for precision or specialized knowledge, and ease of low-level correction and revision. In contrast, most 3D computer modeling systems are good at generating arbitrary views of precise 3D models and support high-level editing andrevision. The SKETCH application described in this paper attempts to combine the advantages of each in order to create an environment for rapidly conceptualizing and editing approximate 3D scenes. To achieve this, SKETCH uses simple non-photorealistic rendering and a purely gestural interface based on simplified line drawings of primitives that allows all operations to be specified within the 3D world.
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