42767167
Location Discovery in Ad Hoc Sensor Networks
46184949
Adaptive Deadlock-Free Wormhole Routing in Faulty Hypercubes
3150650
Fault-Tolerant All-to-All Broadcasting in Hypercubes
29785948
Fast Replacement Route Discovery in Location-Aided Mobile Ad hoc Networks
34087964
Wormhole Routing in Faulty Mesh Networks
17579236
Adaptive topology control for wireless Ad hoc networks
Topology control in ad-hoc networks is the problem of adjusting the transmission power at network nodes in order to achieve the optimal topology that maximizes network performance. Recently, using effective topology control to optimize energy usage in the network has come into focus in the research community [1, 2]. The common thesis arrived at by existing works is that the transmission range used by mobile nodes should be the minimum required to keep the network connected. We refer to such a topology as the minimally connected topology in the rest of the paper. We argue in this work that the minimally connected topology does not always provide the optimal performance in typical ad-hoc networks. We show that in contrast, for typical ad-hoc networks with a few hundred nodes distributed over a few square miles area, the optimal topology is a function of the traffic load.
17481727
Strain analysis and visualization: left ventricle of a heart
Abstract Clinical utility of computational models is crucial in the applications of medical data visualization. Previously we have developed a new class of volumetric models whose parameters are functions in conjunction with physically based deformable modeling framework, and have applied the technique to estimate the left ventricular (LV) wall motion. We have successfully showed that the model parameter functions characterize the LV motion of normal and abnormal states and that no further non-trivial post-processing is required for anatomically meaningful interpretation. In an effort to evaluate the LV model, this paper presents a method and results from a strain analysis based on the nodal displacements of the deformable LV model. Furthermore, in order to visualize the local quantities on the volumetric model for an effective analysis, we also developed a methodology to assist in assessing the cardiac function utilizing principal strains, Von-Mises’ yield criteria, and a smoothing filter. Each strain tensor component was in the range of values observed in other reported studies. The application of a smoothing filter on the model improved in visualizing the overall trend of each strain variation. With our platform for a comprehensive strain analysis, we have augmented a clinical utility to the deformable models with parameter functions.
6873960
A scalable approach for reliable downstream data delivery in wireless sensor networks
There exist several applications of sensor networks wherere liability of data delivery can be critical. While the redundancy inherent in a sensor network might increase the degree of reliability, it by no means can provide any guaranteed reliability semantics. In this paper, we consider the problem of reliable sink-to-sensors data delivery. We first identify several fundamental challenges that need to be addressed, and are unique to a wireless sensor network environment. We then propose a scalable framework for reliable downstream data delivery that is specifically designed to both address and leverage the characteristics of a wireless sensor network, while achieving the reliability in an efficient manner. Through ns2 based simulations, we evaluate the proposed framework.
404376
Power-aware deterministic block allocation for low-power way-selective cache structure
This paper proposes a power-aware cache block allocation algorithm for the way-selective set-associative cache on embedded systems to reduce energy consumption without additional delay or performance degradation. For this goal, way selection logic and specialized replacement policy are designed to enable only one way of set-associative cache as in the direct-mapped cache. Overall cache access time becomes almost the same as that of a conventional set associative cache with accessing additional way selection logic. Because data array can be accessed without waiting for tag comparison, multiplexer delay can be removed totally. The simulation result shows that the proposed architecture can reduce a per access power consumption by 59% over conventional set-associative caches with average 0.06% of negligible performance loss.
1849566
Facility Location and the Geometric Minimum-Diameter Spanning Tree
Let P be a set of n points in the plane. The geometric minimum-diameter spanning tree (MDST) of P is a tree that spans P and minimizes the Euclidian length of the longest path. It is known that there is always a mono- or a dipolar MDST, i.e. a MDST with one or two nodes of degree greater 1, respectively. The more difficult dipolar case can so far only be solved in slightly subcubic time.This paper has two aims. First, we present a solution to a new data structure for facility location, the minimum-sum dipolar spanning tree (MSST), that mediates between the minimum-diameter dipolar spanning tree and the discrete two-center problem (2CP) in the following sense: find two centers p and q in P that minimize the sum of their distance plus the distance of any other point (client) to the closer center. This is of interest if the two centers do not only serve their customers (as in the case of the 2CP), but frequently have to exchange goods or personnel between themselves. We show that this problem can be solved in O(n2 log n) time and that it yields a factor-4/3 approximation of the MDST.Second, we give two fast approximation schemes for the MDST. One uses a grid and takes O*(E6-1/3 + n) time, where E = 1/? and the O*-notation hides terms of type O(logO(1) E). The other uses the well-separated pair decomposition and takes O(nE3+En log n) time. A combination of the two approaches runs in O*(E5 + n) time. Both schemes can also be applied to MSST and 2CP.