5331573
All-to-All Broadcasting in Faulty Hypercubes
A new fault-tolerant all-to-all broadcasting algorithm in an n-dimensional hypercube with up to [n/2] faulty links is given. An extension of this algorithm that can tolerate up to [n/2] faulty nodes is also described. These algorithms assume a multiport I/O model, meaning each node can send and receive messages from all its adjacent nodes simultaneously. The total time steps taken by the proposed algorithms are near optimal, and they produce a factor of n less traffic than previously known algorithms.
42767167
Location Discovery in Ad Hoc Sensor Networks
33219357
Fault-tolerant broadcasting in wormhole-routed torus networks
This paper describes a fault-tolerant broadcast algorithm for wormhole-routed torus networks for which there is only local knowledge of faulty components. This algorithm tolerates tip to k-1 faulty nodes in a k-ary n-cube provided the faults do not cause the network to be disconnected. Based on the fault-tolerant dimension-order unicast communication, this algorithm is deadlock-free and no additional virtual channels are needed. The first stage of this algorithm is itself an optimal broadcast algorithm for a torus if no faults are present. The second stage overcomes the presence of up to k-1 faults with a fixed number of additional message transmissions. Thus, the cost of this algorithm is within a constant factor of the cost of optimal non-fault-tolerant broadcast algorithms.
46184949
Adaptive Deadlock-Free Wormhole Routing in Faulty Hypercubes
35581387
Cluster-based Location Discovery in Ad Hoc Sensor Networks
34087964
Wormhole Routing in Faulty Mesh Networks
17672600
A prototype network embedded in textile fabric
A digital network between active components or "buttons" atop an e-textile fabric must handle the inexact placement of wires in the fabric both for signal distribution and for power distribution. We approach the problem of signal distribution by making the pin logic of the buttons reconfigurable and by providing enough local state to allow an external agent to discover and to reconfigure the buttons into a working network. We describe a prototype system of a 2x2 array of FPGA-and-microcontroller buttons atop a fabric with 0.100"-pitch wiring including architecture decisions, circuits and software algorithms.
16000094
On-line motion blending for real-time locomotion generation
In this paper, we present an integrated framework of on-line motion blending for locomotion generation. We first provide a novel scheme for incremental timewarping, which always guarantees that the time goes forward. Combining the idea of motion blending with that of posture rearrangement, we introduce a motion transition graph to address on-line motion blending and transition simultaneously. Guided by a stream of motion specifications, our motion synthesis scheme moves from node to node in an on-line manner while blending a motion at a node and generating a transition motion at an edge. For smooth on-line motion transition, we also attach a set of example transition motions to an edge. To represent similar postures consistently, we exploit the inter-frame coherency embedded in the input motion specification. Finally, we provide a comprehensive solution to on-line motion retargeting by integrating existing techniques. Copyright © 2004 John Wiley & Sons, Ltd.
2304269
Lightweight logging and recovery for distributed shared memory over virtual interface architecture
As software Distributed Shared Memory(DSM) systems become attractive on larger clusters, the focus of attention moves toward improving the reliability of systems. In this paper, we propose a lightweight logging scheme, called remote logging, and a recovery protocol for home-based DSM. Remote logging stores coherence-related data to the volatile memory of a remote node. The logging overhead can be moderated with high-speed system area network and user-level DMA operations supported by modern communication protocols. Remote logging tolerates multiple failures if the backup nodes of failed nodes are alive. It makes the reliability of DSM grow much higher. Experimental results show that our fault-tolerant DSM has low overhead compared to conventional stable logging and it can be effectively recovered from some concurrent failures.
962129
Bayesian test for asymmetry and nonstationarity in MTAR model with possibly incomplete data
We propose an easy and efficient Bayesian test procedure for asymmetry and nonstationarity in momentum threshold autoregressive model with possibly incomplete data. Estimation of parameters and missing observations is done by using a Markov chain Monte Carlo (MCMC) method. Testing for asymmetry and nonstationarity is done via test of multiple hypotheses representing various types of symmetry/asymmetry and stationarity/nonstationarity. This allows simultaneous consideration of parameters relevant to asymmetry and nonstationarity of the model, and also enables us to find the sources of asymmetry and nonstationarity when they exist. Posterior probabilities of the hypotheses are easily computed by using MCMC outputs under the full model, with almost no extra cost. We apply the proposed method to a set of Korea unemployment rate data.
122654746
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 Euclidean 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, i.e., factor-(1 + e) approximation algorithms. One uses a grid and takes O*(E6-1/3 + n) time, where E = 1/e 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 logn) time. A combination of the two approaches runs in O*(E5 + n) time. Both schemes can also be applied to MSST and 2CP.