We present a new micro-fabrication process to improve the yield of thin film metal strain gauges that are embedded in a poly-dimethyl-siloxane (PDMS) membrane. This work is directed towards the realization of a flexib...
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We present provably efficient parallel algorithms for sweep scheduling on unstructured meshes. Sweep scheduling is a commonly used technique in Radiation Transport problems, and involves inverting an operator by itera...
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ISBN:
(纸本)0769523129
We present provably efficient parallel algorithms for sweep scheduling on unstructured meshes. Sweep scheduling is a commonly used technique in Radiation Transport problems, and involves inverting an operator by iteratively sweeping across a mesh. Each sweep involves solving the operator locally at each cell. However, each direction induces a partial order in which this computation can proceed. On a distributed computing system, the goal is to schedule the computation, so that the length of the schedule is minimized. Several heuristics have been proposed for this problem;see [14, 15] and the references therein;but none of the heuristics have worst case performance guarantees. Here we present a simple, almost linear time randomized algorithm which (provably) gives a schedule of length at most O(log2 n) times the optimal schedule for instances with n cells, when the communication cost is not considered, and a slight variant, which coupled with a much more careful analysis, gives a schedule of (expected) length O(log m log log log m) times the optimal schedule for m processors. These are the first such provable guarantees for this problem. We also design a priority based list schedule using these ideas, with the same theoretical guarantee, but much better performance in practice. We complement our theoretical results with extensive empirical analysis. The results show that (i) our algorithm performs very well and has significantly better performance guarantee in practice and (ii) the algorithm compares favorably with other natural and efficient parallel algorithms proposed in the literature [14, 15].
The adequate location of wells in oil and environmental applications has a significant economical impact on reservoir management. However, the determination of optimal well locations is both challenging and computatio...
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We introduce a novel algorithm for decision tree learning in the multi-instance setting as originally defined by Dietterich et al. It differs from existing multi-instance tree learners in a few crucial, well-motivated...
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ISBN:
(纸本)1595931805
We introduce a novel algorithm for decision tree learning in the multi-instance setting as originally defined by Dietterich et al. It differs from existing multi-instance tree learners in a few crucial, well-motivated details. Experiments on synthetic and real-life datasets confirm the beneficial effect of these differences and show that the resulting system out-performs the existing multi-instance decision tree learners.
A new method for MR to X-ray registration is presented. Based on training data, consisting of registered multispectral MR and CT data, a function is defined that maps multispectral MR data to CT-like data. For new sub...
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Many sensors providing situation data will be in everywhere under the ubiquitous environment. It requires the current RFID system should be extended to recognize and use situation information from the sensors. We alre...
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DiffServ is the basis of contemporary QoS-enabled networks. Setting up DiffServ QoS requires extensive engineering effort in dimensioning and provisioning, especially for adjacent networks under different administrati...
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ISBN:
(纸本)0780395654
DiffServ is the basis of contemporary QoS-enabled networks. Setting up DiffServ QoS requires extensive engineering effort in dimensioning and provisioning, especially for adjacent networks under different administrations linked in a "federated" hierarchy. In this paper we present a case study for QoS techniques employed in the GRNET MAN networks of Athens and Crete. After introducing the supported QoS mechanisms and service types, we discuss our dimensioning methodology and present two algorithms for worst-case dimensioning. We explain the provisioning mechanisms of GRNET and we present in brief our new automated provisioning ANS tool. Finally, we deal with the extension of our mechanisms and tools in hierarchically federated networks and give some future directions of our work.
This work is in the area of parallel discrete event simulation. We consider a conservatively synchronized parallel simulation where submodels consist of multiple entities, each with some amount of lookahead. We explor...
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ISBN:
(纸本)9077381228
This work is in the area of parallel discrete event simulation. We consider a conservatively synchronized parallel simulation where submodels consist of multiple entities, each with some amount of lookahead. We explore the issue of improving the lookahead of a submodel by combining the lookahead abilities of individual entities. We review the concepts and conditions for cumulative lookahead. We provide an experimental evaluation of the effect of cumulative lookahead on simulation performance.
Based on our experience in designing, building and maintaining an information system for supporting a large scale electronic lottery, we present in this paper a unified approach to the design and implementation of ele...
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We present a new methodology for generating and adapting octree meshes for terascale applications. Our approach combines existing methods, such as parallel octree decomposition and space-filling curves, with a set of ...
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