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991.
Result merging methods in distributed information retrieval with overlapping databases 总被引:5,自引:0,他引:5
In distributed information retrieval systems, document overlaps occur frequently among different component databases. This
paper presents an experimental investigation and evaluation of a group of result merging methods including the shadow document
method and the multi-evidence method in the environment of overlapping databases. We assume, with the exception of resultant
document lists (either with rankings or scores), no extra information about retrieval servers and text databases is available,
which is the usual case for many applications on the Internet and the Web.
The experimental results show that the shadow document method and the multi-evidence method are the two best methods when
overlap is high, while Round-robin is the best for low overlap. The experiments also show that [0,1] linear normalization
is a better option than linear regression normalization for result merging in a heterogeneous environment.
相似文献
Sally McCleanEmail: |
992.
Brian Edward Hubner 《Archival Science》2007,7(3):195-206
Census information of some form has been collected in Canada since the 1611 census of New France. Aboriginal people, identified
or not, have been included in these enumerations. The collection of this information has had a profound impact on Aboriginal
people and has been an element that has shaped their relationship with the dominant society. In response, Canadian Aboriginal
people have often resisted and refused to co-operate with census takers and their masters. This article is an examination
of this phenomenon focused on the censuses conducted in the post-Confederation period to the present. A census is made to
collect information on populations and individuals that can then be used to configure and shape social and political relations
between those being enumerated and the creators of the census. However, the human objects of the census are not just passive
integers and they have resisted its creation in a number of ways, including being “missing” when the census is taken, refusing
to answer the questions posed by enumerators or even driving them off Aboriginal territory. A census identifies elements of
the social order and attempts to set them in their “proper” place and those who do not wish to be part of that order may refuse
to take part. Archivists and historians must understand that the knowledge gained in a census is bound with the conditions
of own creation. This has been noted by contemporary Aboriginal researchers who often state that the archival record of their
people often distorts history and reflects the ideas and superficial observations of their Euro-Canadian creators. Changes
to the Census of Canada since 1981, have increased the participation rate and therefore changed the nature of the record.
Brian Edward Hubner is currently Acquisition and Access Archivist at the University of Manitoba Archives & Special Collections. He was previously employed at the Archives of Manitoba, in Government Records; Queen’s University Archives, Kingston; and at the National Archives of Canada, Ottawa. He has a Master of Arts (History, in Archival Studies) from the University of Manitoba, and a Master of Arts (History), from the University of Saskatchewan. The 2nd edition of Brian’s co-authored book on the history of the Cypress Hills of Saskatchewan and Alberta is being published in 2007. He has published articles and delivered conference papers on Canadian Aboriginal peoples including “Horse Stealing and the Borderline: The N.W.M.P. and the Control of Indian Movement, 1874-1900.” His current research interest focuses on relationship between Canada’s Aboriginal Peoples and Canadian archives. Brian is married and has two children. 相似文献
Brian Edward HubnerEmail: |
Brian Edward Hubner is currently Acquisition and Access Archivist at the University of Manitoba Archives & Special Collections. He was previously employed at the Archives of Manitoba, in Government Records; Queen’s University Archives, Kingston; and at the National Archives of Canada, Ottawa. He has a Master of Arts (History, in Archival Studies) from the University of Manitoba, and a Master of Arts (History), from the University of Saskatchewan. The 2nd edition of Brian’s co-authored book on the history of the Cypress Hills of Saskatchewan and Alberta is being published in 2007. He has published articles and delivered conference papers on Canadian Aboriginal peoples including “Horse Stealing and the Borderline: The N.W.M.P. and the Control of Indian Movement, 1874-1900.” His current research interest focuses on relationship between Canada’s Aboriginal Peoples and Canadian archives. Brian is married and has two children. 相似文献
993.
Beatrice S. Bartlett 《Archival Science》2007,7(4):369-390
This article describes the first half century of the Communist government’s supervision and management of the central-government
archives of the last two dynasties. Immediately with the Communist ascent to power in 1949, the new government took great
interest in assembling and protecting the country’s archival documents, readying the Ming-Qing archives for access to scholars,
and preparing for publication of selected materials. By the 1980s Beijing’s Number One Historical Archives, in charge of the
largest holding of Ming-Qing documents, had become the first Chinese authority to complete a full sorting and preliminary
catalogues for such a collection. Moreover, to facilitate searches, an attempt has recently begun to create a subject-heading
system for these and other holdings in the country. In the first half century’s final decades, foreign researchers were admitted
for the first time and tours and international exchanges began to take place.
相似文献
Beatrice S. BartlettEmail: |
994.
Previous papers on grey literature by the authors have described (1) the need for formal metadata to allow machine understanding
and therefore scalable operations; (2) the enhancement of repositories of grey (and other) e-publications by linking with
CRIS (Current Research Information Systems); (3) the use of the research process to collect metadata incrementally reducing
the threshold barrier for end-users and improving quality in an ambient GRIDs environment. This paper takes the development
one step further and proposes “intelligent” grey objects. The hypothesis is in 2 parts: (1) that the use of passive catalogs
of metadata does not scale (a) in a highly distributed environment with millions of nodes and (b) with vastly increased volumes
of R&D output grey publications with associated metadata; (2) that a new paradigm is required that (a) integrates grey with
white literature and other R&D outputs such as software, data, products and patents (b) in a self-managing, self-optimizing
way and that this paradigm manages automatically curation, provenance digital rights, trust, security and privacy. Concerning
(1) existing repositories provide catalogs; harvesting takes increasing time ensuring non-currency. The end-user expends much
manual effort/intelligence to utilize the results. The elapsed time of (1) the network (2) the centralized (or centrally controlled
distributed) catalog server searches (3) end-user intervention becomes unacceptable. Concerning (2) there is no paradigm currently
known to the authors that satisfies the requirement. Our proposal is outlined below. Hyperactive combines both hyperlinking
and active properties of a (grey) object. Hyperlinking implies multimedia components linked to form the object and also external
links to other resources. The term active implies that objects do not lie passively in a repository to be retrieved by end-users.
They “get a life” and the object moves through the network knowing where it is going. A hyperactive grey object is wrapped
by its (incrementally recorded) formal metadata and an associated (software) agent. It moves through process steps such as
initial concept, authoring, reviewing and depositing in a repository. The workflow is based on the rules and information in
the corporate data repository with which the agent interacts. Once the object is deposited, the agent associated with it actively
pushes the object to the end-users (or systems) whose metadata indicate interest or an obligation in a workflowed process.
The agents check the object and user (or system) metadata for rights, privacy, security parameters, and for any charges and
assure compatibility. Alternatively the object can be found passively by end-user or system agents. The object can also associate
itself with other objects forming relationships utilising metadata or content. Declared relationships include references and
citations; workflowed relationships include versions and also links to corporate information and research datasets and software;
inferenced relationships are discovered relationships such as between documents by different authors developed from an earlier
idea of a third author. Components of this paradigm have been implemented to some extent. The challenge is implementing—respecting
part two of the hypothesis—the integration architecture. This surely is harnessing the power of grey.
相似文献
Anne AssersonEmail: |
995.
996.
This article analyses the extent to which archival exemptions for historical, scientific and statistical research in privacy
legislation support preservation in selected European Union countries, and comparable aspects of Australian, American and
Canadian law within a legal, ethical and digital archival perspective. The authors recommend that the further processing of
personal data under data protection law be given a wider scope of interpretation for archival preservation purposes in both
the public and private sector, coupled with the use of researcher and archival codes in relation to access to personal data.
They also recommend early appraisal and integration of privacy with freedom of information and archival regimes.
相似文献
Malcolm ToddEmail: |
997.
Joanna Sassoon 《Archival Science》2007,7(2):133-145
The emergence of the new format of electronic/digital records provides the opportunity for archivists to reconsider the presumed
format-neutrality of professional practice. As research in electronic records has served to re-emphasise, without an understanding
of the needs and forms of material, then the work of archivists can have a profound impact on the evidential value and long-term
research potential of the material. This paper attempts to broaden the debate about the requirements of all archival formats,
and to build a new regime of 21st-century format specialists.
Dr. Joanna Sassoon is currently seconded to Edith Cowan University as Senior Lecturer in the School of Computer and Information Science. Her permanent position is in the State Records Office of Western Australia. She has long experience in managing archival collections, and has written extensively on a range of topics including digitisation, the effect of institutional practice on archival materials, environmental and indigenous history, and photographs as archives, and her work has been recognised with two Mander-Jones awards from the Australian Society of Archivists. She holds a Ph.D. in history with distinction from the University of Western Australia. 相似文献
Joanna SassoonEmail: |
Dr. Joanna Sassoon is currently seconded to Edith Cowan University as Senior Lecturer in the School of Computer and Information Science. Her permanent position is in the State Records Office of Western Australia. She has long experience in managing archival collections, and has written extensively on a range of topics including digitisation, the effect of institutional practice on archival materials, environmental and indigenous history, and photographs as archives, and her work has been recognised with two Mander-Jones awards from the Australian Society of Archivists. She holds a Ph.D. in history with distinction from the University of Western Australia. 相似文献
998.
We used an appetitive sensory preconditioning procedure to investigate temporal integration in rats in two experiments. In
Phase 1, rats were presented with simultaneous compound trials on which a 10-sec conditioned stimulus (CS) X was embedded
within a 60-sec CS A. In Group Early, CS X occurred during the early portion of CS A, whereas in Group Late, CS X occurred
during the latter portion of CS A. In Phase 2, CS X was paired simultaneously with sucrose. On a subsequent test with CS A,
the rate of magazine entries peaked during the early portions of the stimulus in Group Early and during the latter portions
of the stimulus in Group Late (Experiments 1 and 2). Similar response peaks were not observed on tests with a control stimulus
that had been presented in compound with a stimulus that did not signal reward (Experiment 2). 相似文献
999.
In two experiments, participants inspected and drank a series of drinks, half of which contained sugar and half unpalatable
Tween20 (tween). Each sugar and tween drink had a particular flavor and color. Following this training, the flavors of the
sugar drinks were assigned higher hedonic evaluations than were those of the tween drinks, even though the participants did
not reliably report which flavors had been present in the sugar and tween drinks during training. Moreover, the evaluative
conditioning of the flavors was unaffected by whether or not the colors alone had been pretrained to predict the presence
of sugar or tween in the drinks. In accord with Baeyens, Eelen, van den Bergh, and Crombez (1990), we conclude that flavor-evaluative
conditioning is not mediated by contingency learning. 相似文献
1000.
In four experiments with rats, we examined the persistence of behavior when reinforcement was switched from immediate to delayed.
In Experiment 1, lever pressing elicited by instrumental training with immediate reinforcement continued when a 20-sec delay
of reinforcement was introduced (easy-to-hard condition), whereas when the delay condition was introduced from the start (hard-to-hard
condition), responding remained low throughout. A similar result was obtained in Experiment 2, in which lever pressing was
elicited by a classical conditioning (autoshaping) procedure. In Experiment 3, rats initially trained with delayed reinforcement
continued to respond at a low rate when switched to immediate reinforcement (hard-to-easy condition). By measuring magazine
entry (goal tracking) as well as lever pressing (sign tracking) in Experiment 4, we confirmed that such transfer effects at
least partly involve the persistence of whatever type of behavior was initially dominant. 相似文献