7373402
Co-cited author maps as interfaces to digital libraries: designing Pathfinder Networks in the humanities
Using data from the Arts and Humanities Citation Index for 1988-1997, we are attempting to generate co-cited author maps in real time that can serve as interfaces for document retrieval. Our novel approach is to start the maps by entering the name of a single author. Our system obtains a rank-ordered list of the other authors who are most often co-cited with the input name (e.g., the top 50) and then systematically pairs these other authors in turn to obtain their co-citation counts. The resulting matrix can be passed to a mapping program which groups the authors meaningfully to show the structure of the field implied by the input author's name. At present we are experimenting with Pathfinder Networks (PFNETs) as the mapping program, and show a PFNET for 25 authors in hermeneutics, a major field of the humanities. The documents co-citing the mapped authors are candidates for retrieval. We discuss desirable features and design considerations in retrieval interfaces based on PFNETs.
2535403
Visualization for the document space
An information retrieval frame work that promotes graphical displays, and that will make documents in the computer visualizable to the searcher, is described. As examples of such graphical displays, two simulation results of using a Kohonen feature map to generate map displays for information retrieval are presented and discussed. The map displays are a mapping from a high-dimensional document space to a two-dimensional space. They show document relationships by various visual cues, such as dots, links, clusters, and areas, as well as their measurement and spatial arrangement. Using the map displays as an interface for document retrieval systems, the user is provided with richer visual information to support browsing and searching.<<ETX>>
207195547
Graphical table of contents
This paper proposes a graphical table of contents (GTOC) that is functionally analogous to the table of contents. The proposed GTOC can be generated automatically from the text of documents. It visualizes document contents and relationships to allow easy access of underlying documents. It also provides various interactive tools to let the user explore the documents. Issues of how to generate such GTOC include how documents are indexed and organized, how the organized documents are visualized, and what interactive means are needed to provide necessary functionality of GTOC. These issues are discussed in this paper with a GTOC prototype based on Kohonen’s selforganizing featore map algorithm.
18690541
Real-time author co-citation mapping for online searching
Author searching is traditionally based on the matching of name strings. Special characteristics of authors as personal names and subject indicators are not considered. This makes it difficult to identify a set of related authors or to group authors by subjects in retrieval systems. In this paper, we describe the design and implementation of a prototype visualization system to enhance author searching. The system, called AuthorLink, is based on author co-citation analysis and visualization mapping algorithms such as Kohonen's feature maps and Pathfinder networks. AuthorLink produces interactive author maps in real time from a database of 1.26 million records supplied by the Institute for Scientific Information. The maps show subject groupings and more fine-grained intellectual connections among authors. Through the interactive interface the user can take advantage of such information to refine queries and retrieve documents through point-and-click manipulation of the authors' names.
21113165
Graphical representations of electronic search patterns
Increasing numbers of researchers and developers are collecting data that trace the processes of humancomputer interactions. Although a variety of methods are used to collect such data, all researchers share common problems in representing and analyzing continuous streams of data. A set of methods and tools for graphically representing the search patterns of users interacting with a variety of databases and hypertexts is under development as part of ongoing research in electronic information seeking. The methodology described in this article involves defining state spaces of user options within a system, capturing keystrokes or mouse moves as raw data, coding these data into the state spaces, and analyzing user moves through the state space as evidence of goal-directed informationseeking strategies and patterns. A tool for displaying user moves through a state space has been developed and is described. The tool graphically represents data in a variety of formats, allowing human pattern recognition capabilities to be applied for data analysis. Graphs can be represented for individual searches or for multiple searches done by either a single searcher or by several searchers working on the same search task.
32681772
Visual MeSH
Visual MeSH is a graphical interface developed to interact with real world databases such as the National Library of Medicine’s MetaThesaurus and MEDLINE. Visual MeSH makes it easy for the user to browse complex relationships through visual representation of thesaurus structures. It helps the user to select controlled vocabulary terms for online searching in the click-andchoose environment.
15723189
Impact of imperfect OCR on part-of-speech tagging
Part-of-speech (POS) tagging is the foundation of natural language processing (NLP) systems, and thus has been an active area of research for many years. However, one question remains unanswered: How will a POS tagger behave when the input text is not error-free? This issue can be of great importance when the text comes from imperfect sources like optical character recognition (OCR). This paper analyzes the performance of both individual POS taggers and combination systems on imperfect text. Experimental results show that a POS tagger's accuracy decreases linearly with the character error rate and the slope indicates a tagger's sensitivity to input text errors.
14038708
Efficiently computing frequent tree-like topology patterns in a Web environment
Data mining has recently emerged in a number of real life applications, such as banking, supermarketing, and interneting. The authors investigate a novel data mining problem derived from the applications of WWW. They present an efficient algorithm for solving the problem. The initial implementation suggests that the algorithm is very efficient and scalable in practice.
28914040
Low-Complexity Distributed Scheduling Algorithms for Wireless Networks
We consider the problem of distributed scheduling in wireless networks. We present two different algorithms whose performance is arbitrarily close to that of maximal schedules, but which require low complexity due to the fact that they do not necessarily attempt to find maximal schedules. The first algorithm requires each link to collect local queue-length information in its neighborhood, and its complexity is independent of the size and topology of the network. The second algorithm is presented for the node-exclusive interference model, does not require nodes to collect queue-length information even in their local neighborhoods, and its complexity depends only on the maximum node degree in the network.
19601209
Pricing-Based Control of Large Networks
In this work we study pricing as a mechanism to control large networks. Our model is based on revenue maximization in a general loss network with Poisson arrivals and arbitrary holding time distributions. In dynamic pricing schemes, the network provider can charge different prices to the user according to the current utilization level of the network. We show that, when the system becomes large, the performance of an appropriately chosen static pricing scheme, whose price is independent of the current network utilization, will approach that of the optimal dynamic pricing scheme. Further, we show that under certain conditions, this static price is independent of the route that the connections take. This result has the important implication that distance-independent pricing that is prevalent in current domestic telephone networks in the U.S. may in fact be appropriate not only from a simplicity, but also a performance point of view. We also show that in large systems prior knowledge of the connection holding time is not important from a network revenue point of view.
1773095
Delay Optimization in Quorum Consensus
Abstract
 The management of replicated data in distributed database systems is a classic problem with great
practical importance. Quorum consensus is one of the popular methods, combined with eager replication, for
managing replicated data. In this paper we investigate the problems of delay-optimal quorum consensus.
Firstly, we show that the problem of minimizing the total delay (or mean delay) restricted to a ring can be
solved in a constant time in contrast to the existing approximation results. Secondly, we show that the problem
of minimizing the total delay (or mean delay) is NP-hard. Thirdly, we present an approximate algorithm with
an approximate ratio 2; and the approximate algorithm can guarantee the exact solutions for some specific
network topology, such as trees and meshes. Finally, we present an improvement on the existing algorithm
to solve the problem of minimizing the maximal delay; this reduces the time complexity from O(n3 log n) to
O(n3) where n is the number of nodes.