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Computer Sciences

2002

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Articles 511 - 524 of 524

Full-Text Articles in Physical Sciences and Mathematics

Thread Transparency In Information Flow Middleware, Rainer Koster, Andrew P. Black, Jie Huang, Jonathan Walpole, Calton Pu Jan 2002

Thread Transparency In Information Flow Middleware, Rainer Koster, Andrew P. Black, Jie Huang, Jonathan Walpole, Calton Pu

Computer Science Faculty Publications and Presentations

Existing middleware is based on control-flow centric interaction models such as remote method invocations, poorly matching the structure of applications that process continuous information flows. Difficulties cultiesin building this kind of application on conventional platforms include flow-specific concurrency and timing requirements, necessitating explicit management of threads, synchronization, and timing by the application programmer. We propose Infopipes as a high-level abstraction for information flows, and we are developing a middleware framework that supports this abstraction. Infopipes transparently handle complexities associated with control flow and multi-threading. From high-level configuration descriptions the platform determines what parts of a pipeline require separate threads or …


A Comparison Of Evolutionary And Coevolutionary Search, Ludo Pagie, Melanie Mitchell Jan 2002

A Comparison Of Evolutionary And Coevolutionary Search, Ludo Pagie, Melanie Mitchell

Computer Science Faculty Publications and Presentations

Previous work on coevolutionary search has demonstrated both successful and unsuccessful applications. As a step in explaining what factors lead to success or failure, we present a comparative study of an evolutionary and a coevolutionary search model. In the latter model, strategies for solving a problem coevolve with training cases. We find that the coevolutionary model has a relatively large efficacy: 86 out of 100 (86%) of the simulations produce high quality strategies. In contrast, the evolutionary model has a very low efficacy: a high quality strategy is found in only two out of 100 runs (2%). We show that …


Transparent Fault Tolerance For Web Services Based Architectures, Vijay Dialani, Simon Miles, Luc Moreau, David De Roure, Michael Luck Dec 2001

Transparent Fault Tolerance For Web Services Based Architectures, Vijay Dialani, Simon Miles, Luc Moreau, David De Roure, Michael Luck

Vijay Dialani

Service-based architectures enable the development of new classes of Grid and distributed applications. One of the main capabilities provided by such systems is the dynamic and flexible integration of services, according to which services are allowed to be a part of more than one distributed system and simultaneously serve different applications. This increased flexibility in system composition makes it difficult to address classical distributed system issues such as fault-tolerance. While it is relatively easy to make an individual service fault-tolerant, improving fault-tolerance of services collaborating in multiple application scenarios is a challenging task. In this paper, we look at the …


Synchronization Of The Human Cortical Working Memory Network, Sharlene Newman, Marcel Just, Patricia Carpenter Dec 2001

Synchronization Of The Human Cortical Working Memory Network, Sharlene Newman, Marcel Just, Patricia Carpenter

Marcel Adam Just

No abstract provided.


A Compilation Of Soybean Ests: Generation And Analysis, Elizabeth Shoop, R. Schoemaker, Et Al Dec 2001

A Compilation Of Soybean Ests: Generation And Analysis, Elizabeth Shoop, R. Schoemaker, Et Al

Elizabeth Shoop

No abstract provided.


Logic, Optimization And Constraint Programming, John Hooker Dec 2001

Logic, Optimization And Constraint Programming, John Hooker

John Hooker

No abstract provided.


On The Convergence Of Puck Clustering Systems, S. Kazadi, A. Abdul-Khaliq, R. Goodman Dec 2001

On The Convergence Of Puck Clustering Systems, S. Kazadi, A. Abdul-Khaliq, R. Goodman

Sanza Kazadi

Puck clustering involves the physical relocation of small objects known as ‘pucks’ from random positions to a central location, which need not be specified a priori. The evolution of systems of clusters of pucks under the action of robots capable of moving pucks from several locations is considered. A general set of conditions by which a puck collection system may be seen to evolve to a one-cluster system is developed. General conditions leading to clustering behavior in the presence and absence of non-embodied agents are derived. Conditions leading to more efficient algorithms are also derived. Several examples are given to …


Features For Word Spotting In Historical Manuscripts, Toni M. Rath, R. Manmatha Dec 2001

Features For Word Spotting In Historical Manuscripts, Toni M. Rath, R. Manmatha

R. Manmatha

For the transition from traditional to digital libraries, the large number of handwritten manuscripts that exist pose a great challenge. Easy access to such collections requires an index, which is currently created manually at great cost. Because automatic handwriting recognizers fail on historical manuscripts, the word spotting technique has been developed: the words in a collection are matched as images and grouped into clusters which contain all instances of the same word. By annotating ``interesting clusters," an index that links words to the locations where they occur can be built automatically.

Due to the noise in historical documents, selecting the …


Word Image Matching Using Dynamic Time Warping, Toni M. Rath, R. Manmatha Dec 2001

Word Image Matching Using Dynamic Time Warping, Toni M. Rath, R. Manmatha

R. Manmatha

Libraries and other institutions are interested in providing access to scanned versions of their large collections of handwritten historical manuscripts on the web or on CDROMs. Providing convenient access to a collection requires an index which is manually created at great labour and expense. Since current handwriting recognizers do not perform well on historical documents, a technique called word spotting has been developed. It addresses the need for indexing single-author handwritten historical manuscripts in a new way: word images are matched to form clusters which contain occurrences of the same word throughout a collection. By annotating ``interesting" clusters, an index …


A Formal Approach To Score Normalization For Metasearch, H. Sever, R. Manmatha Dec 2001

A Formal Approach To Score Normalization For Metasearch, H. Sever, R. Manmatha

R. Manmatha

Meta-search, or the combination of the outputs of different search engines in response to a query, has been shown to improve performance. Since the scores produced by different search engines are not comparable, researchers have often decomposed the metasearch problem into a score normalization step followed by a combination step. Combination has been studied by many researchers. While appropriate normalization can affect performance, most of the normalization schemes suggested are ad hoc in nature.

In this paper, we propose a formal approach to normalizing scores for meta-search by taking the distributions of the scores into account. Recently, it has been …


An Fmri Study Of Bilingual Sentence Comprehension And Workload, Mihoko Hasegawa, Patricia A. Carpenter, Marcel Adam Just Dec 2001

An Fmri Study Of Bilingual Sentence Comprehension And Workload, Mihoko Hasegawa, Patricia A. Carpenter, Marcel Adam Just

Marcel Adam Just

No abstract provided.


A Critical Examination Of Tdt’S Cost Function, R. Manmatha, Ao Feng, James Allan Dec 2001

A Critical Examination Of Tdt’S Cost Function, R. Manmatha, Ao Feng, James Allan

R. Manmatha

Topic Detection and Tracking (TDT) tasks are evaluated using a cost function. The standard TDT cost function assumes a constant probability of relevance P(rel) across all topics. In practice, P(rel) varies widely across topics. We argue using both theoretical and experimental evidence that the cost function should be modified to account for the varying P(rel).


Indexing For A Digital Library Of George Washington’S Manuscripts: A Study Of Word Matching Techniques, T. M. Rath, S. Kane, A. Lehman, E. Partridge, R. Manmatha Dec 2001

Indexing For A Digital Library Of George Washington’S Manuscripts: A Study Of Word Matching Techniques, T. M. Rath, S. Kane, A. Lehman, E. Partridge, R. Manmatha

R. Manmatha

In a multimedia world, one would like electronic access to all kinds of information. But a lot of important information still only exists on paper and it is a challenge to efficiently access or navigate this information even if it is scanned in. The previously proposed \word spotting" idea is an approach for accessing and navigating a collection of handwritten documents available as images using an index automatically generated by matching words as pictures. The most difficult task in solving this problem is the matching of word images. The quality of the aged documents and the variations in handwriting make …


Candidate Set Strategies For Ant Colony Optimisation, Marcus Randall, James Montgomery Dec 2001

Candidate Set Strategies For Ant Colony Optimisation, Marcus Randall, James Montgomery

Marcus Randall

Ant Colony Optimisation based solvers systematically scan the set of possible solution elements before choosing a particular one. Hence, the computational time required for each step of the algorithm can be large. One way to overcome this is to limit the number of element choices to a sensible subset, or candidate set. This paper describes some novel generic candidate set strategies and tests these on the travelling salesman and car sequencing problems. The results show that the use of candidate sets helps to find competitive solutions to the test problems in a relatively short amount of time.