3150650
Fault-Tolerant All-to-All Broadcasting in Hypercubes
35581387
Cluster-based Location Discovery in Ad Hoc Sensor Networks
206892687
Recycled path routing in mobile ad hoc networks
In mobile ad hoc networks, many routing algorithms rely on some form of flooding to accomplish the route discovery process. Flooding, however, consumes many valuable network resources such as time, bandwidth, and power. Most current routing schemes expire valid routes after a time period to account for nodal movement. This paper proposes a new route discovery method, called recycled path routing (RPR), which directs broadcasts toward the destination node even in the absence of location information. The recycled path routing scheme reduces the search space for the destination node by implementing an expired route cache that is utilized by each node in the network. Routes are added to the expired route cache as they expire from the active route cache and remain there until some time interval has passed or a new route has been discovered. Since these expired routes can provide valuable insight into finding new routes, RPR uses them to direct broadcasts toward the destination node. RPR can save a significant quantity of valuable network resources because only nodes near the optimal path will rebroadcast route requests.
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.
38077943
Position-Based Topology-Independent Scheduling Algorithms for Mobile Ad Hoc 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.
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.
5736489
Architecture for Implementing the Mobile Government Services in Korea
Each nation’s architecture for the m-Government including Korea’s is being laid out somewhat differently according to its strategy, approach, and its own structural conditions and challenges. Despite such differences, all of them are making numerous efforts to establish the advanced service architecture for the m-Government. In the meantime, they are confused in securing and managing strategic resources which are needed to create constant mobile values, diversifying wired and wireless connection sections, and dealing with technological complexities and differences in various kinds of mobile technologies. Therefore, this study proposes the m-Government service architecture, which can effectively provide nationwide m-Governmental services. It also defines key components of the m-Government service architecture and specific characteristics of applied technologies.
16093001
Textiles and computing: background and opportunities for convergence
John Kay's invention of the flying shuttle in 1733 sparked the first Industrial Revolution, which led to the transformation of industry and subsequently of civilization itself. Yet another invention in the field of textiles - the Jacquard head by Joseph Marie Jacquard (circa 1801) - was the first binary information processor. At any given point, the thread in a woven fabric can be in one of two states or positions: on the face of the fabric or on the back. Pattern cards were punched or cut according to the required fabric design. A hole in the card signified that the thread would appear on the face of the fabric, while a blank meant that the end would be left down and appear on the back of the fabric. The Jacquard head was used on the weaving loom or machine for raising and lowering the warp threads to form desired patterns based on the lifting plan or program embedded in the cards. Thus the Jacquard mechanism set the stage for modern day binary information processing. Ada Lovelace, the benefactor for Charles Babbage who worked on the Analytical Engine (the predecessor to the modern day computer), is said to have remarked, "The Analytical Engine weaves algebraic patterns just as the Jacquard loom weaves flowers and leaves." The Jacquard mechanism that inspired Babbage and spawned the Hollerith punched card has been instrumental in bringing about one of the most profound technological advancements known to humans, viz., the second Industrial Revolution also known as the Information Processing Revolution [1]. In fact, when Intel introduced its Pentium class of microprocessors, one of the advertisements had a "fabric of chips" emerging from a weaving machine; this picture eloquently captured the essence of chip making - a true blending of art and science - much like the design and production of textiles.
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.
15182689
Chameleon: a resource scheduler in a data grid environment
Grid computing is moving into two ways. The Computational Grid focuses on reducing execution time of applications that require a great number of computer processing cycles. The Data Grid provides the way to solve large scale data management problems. Data intensive applications such as High Energy Physics and Bioinformatics require both Computational and Data Grid features. Job scheduling in Grid has been mostly discussed from the perspective of computational Grid. However, scheduling on Data Grid is just a recent focus of Grid computing activities. In Data Grid environment, effective scheduling mechanism considering both computational and data storage resources must be provided for large scale data intensive applications. In this paper, we describe new scheduling model that considers both amount of computational resources and data availability in Data Grid environment. We implemented a scheduler, called Chameleon, based on the proposed application scheduling model. Chameleon shows performance improvements in data intensive applications that require both large number of processors and data replication mechanisms. The results achieved from Chameleon are presented.