1442053
User preferences when searching individual and integrated full-text databases
This paper addresses a crucial issue in the digital library environment: how to support effective interaction of users with heterogeneous and distributed information resources. We compared users' preference for systems which implement interaction with multiple databases through a common interface and with multiple databases as if they were one (integrated interaction) in an experiment in the Text REtrieval Conference (TREC) environment. Twenty-eight volunteers were recruited from the graduate students of School of Communication, Information, & Library Studies at Rutgers University. Significantly more subjects preferred the common interface (HERMES) to the integrated interface (HERA). For most of the subjects in this study, the greater control in HERMES outweighed the advantages of HERA such as convenience, efficiency, and ease of use. These results suggest that: (1) the general assumption of the information retrieval (IR) literature that an integrated interaction is best needs to be revisited; (2) it is important to allow for more user control in various ways in the distributed environment; and (3) for digital library purposes, it is important to characterize different databases to support user choice for integration.
34137561
Using Relevance Feedback and Ranking in Interactive Searching
We present results of a study in which 50 searchers, of varying degrees of experience in information retrieval (IR), each performed searches on two TREC-4 adhoc interactive track topics, using a simple interface to the INQUIRY retrieval engine. The foci of our study were : the relationships between the users'models and experience of IR, and their performance in the TREC-4 adhoc task while using a best-match IR system with relevance feedback ; the understanding, use and utility of relevance feedback and ranking in interactive IR ; and, the evaluation of interactive IR.
36047409
A Comparison of Scalable Labeling Schemes for Detecting Races in OpenMP Programs
Detecting races is important for debugging shared-memory parallel programs, because the races result in unintended nondeterministic executions of the program. On-the-fly technique to detect races uses a scalable labeling scheme which generates concurrency information of parallel threads without any globally-shared data structure. Two efficient schemes of scalable labeling, BD Labeling and NR Labeling, show the similar complexities in space and time, but their actual efficiencies have been compared empirically in no literature to the best of our knowledge. In this paper, we empirically compare these two labeling schemes by monitoring a set of OpenMP kernel programs with nested parallelism. The empirical results show that NR Labeling is more efficient than BD Labeling by at least 1.5 times in generating the thread labels, and by at least 3.5 times in using the labels to detect races in the kernel programs.
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.
195862521
The wearable motherboard: a framework for personalized mobile information processing (PMIP)
Textiles and computing share a synergistic relationship, which is being harnessed to create a new paradigm in personalized mobile information processing (PMIP). In this paper, we provide an overview of this "interconnection" between the two fields and present the vision for "E-Textiles," which represents the convergence of the two fields. We discuss the role of the Georgia Tech Wearable Motherboard in pioneering this paradigm of "fabric is the computer" and serving as a framework for PMIP. Finally, recent research in this area resulting in the realization of a "computational fabric network" is discussed.
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.
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.