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.
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.
6353910
Rhythmic-motion synthesis based on motion-beat analysis
Real-time animation of human-like characters is an active research area in computer graphics. The conventional approaches have, however, hardly dealt with the rhythmic patterns of motions, which are essential in handling rhythmic motions such as dancing and locomotive motions. In this paper, we present a novel scheme for synthesizing a new motion from unlabelled example motions while preserving their rhythmic pattern. Our scheme first captures the motion beats from the example motions to extract the basic movements and their transitions. Based on those data, our scheme then constructs a movement transition graph that represents the example motions. Given an input sound signal, our scheme finally synthesizes a novel motion in an on-line manner while traversing the motion transition graph, which is synchronized with the input sound signal and also satisfies kinematic constraints given explicitly and implicitly. Through experiments, we have demonstrated that our scheme can effectively produce a variety of rhythmic motions.
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.
37317818
Practice and Experience of an Embedded Processor Core Modeling
This paper presents our experience in developing an embedded processor core model for an SOC design. We developed an ARM1136 processor simulation environment based on the ARM's MaxCore tool and the SimpleScaclar simulator. A MaxCore ARM1136 instruction accurate (IA) model is developed to support application programmers for the writing application programs from the early design stage. The MaxCore ARM1136 processor model supports all ARMv4, ARMv5TE and ARM v6 instruction sets with 418 LISA instructions. This MaxCore IA Model can be integrated with the ARM's MaxSim system level design environment to develop application softwares and perform architecture explorations. A SimpleScalar ARM1136 cycle accurate (CA) model is also developed by enhancing the existing SimpleScalar-ARM version in the SimpleScalar 3.0. Most important micro-architectural features of ARM1136 processor are implemented in the enhanced SimpleScalar simulator. The accuracy of the developed SimpleScalar-ARM 1136 simulator is about 97% compared to ARM 1136 RTL simulation with the Dhrystone benchmark (100 iterations).
1455414
A Comparison of the Two Traditions of Metadata Development
The two traditional methods of Metadata Development as describe in the article are bibliographic control approach and the data management approach. These two approaches have evolved over time due to the rise of digital information stored in cyberspace and help facilitate metadata standards which include the identification, location, retrieval, manipulation and use of the information. So what is metadata? From my understanding of what metadata is, metadata is simply defined as 'data about data'. And to a certain extent and depending on the perspective which you define what metadata is, 'data about data' is a legitimate and accurate definition. Soyeon Park (1999), define metadata as " structured data about data " whereas NISO Press, 2004 describes metadata as " data about data or information about information. " But according to Gill, 2000, " information about information " is often " incorrectly generalized " by the reader or author as the meaning of metadata, therefore, 'data about data' would be more concise and accurate for this paper. This begs the question of exactly the purpose of metadata and metadata standards. In theory, " metadata provides an effective mechanism for identifying and locating data that is relevant to a particular user. " elements within the metadata standards may be divided into two categories: intrinsic (related to resource identification and discovery) and extrinsic (related administration and other nonbibliographic data). While some metadata formats vary in terms of intrinsic and extrinsic elements, some elements are more suitable for resource description and identification whereas others may help resource access and navigation. However, the issue still remains as to which metadata format to use and whether a universal or unified " grand scheme " that is rich in attribute should be employed, eliminating the need in choosing a specific metadata format. In the past years, we have seen a rise of conflicting standards as an increasingly large amount of information becomes available electronically. This has become a growing problem as retrieving information becomes more complex. In an article by Jessica Milstead and Susan Feldman (1999), the author uses the term " Mercury " as an example of the documents the user would retrieve through the use of
439941
Iterative exploration, design and evaluation of support for query reformulation in interactive information retrieval
We report on the progressive investigation of techniques for supporting interactive query reformulation in the TREC Interactive Track. Two major issues were explored over four successive years: methods of term suggestion; and, interface design to support different system functionalities. Each year's results led to the following year's investigation, with respect to both of these issues. This paper presents first the general motivation for the entire series of studies; then an overview of each year's investigation, its results, and how they influenced the next year's investigation. We discuss what has been learned through this series of investigations about effective term suggestion, usable and useful interface design, and the relationships between these two in support of the TREC Interactive Track task. We conclude with comments about the general methodology employed over this series of studies, and its relevance to the development and evaluation of interactive information retrieval systems.