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171.
Three aspects of the most important problem questionused in agenda-setting research to measure issue salience amongthe public were examined. A split-ballot design in a state-widesurvey compared versions of the public agenda with a socialframe of reference versus a personal frame of reference, versionsusing the traditional term problem versus issue,and the effects of question order. High correlations betweenthe different versions were found in all three sets of comparisons. 相似文献
172.
Intelligent use of the many diverse forms of data available on the Internet requires new tools for managing and manipulating
heterogeneous forms of information. This paper uses WHIRL, an extension of relational databases that can manipulate textual
data using statistical similarity measures developed by the information retrieval community. We show that although WHIRL is
designed for more general similarity-based reasoning tasks, it is competitive with mature systems designed explicitly for
inductive classification. In particular, WHIRL is well suited for combining different sources of knowledge in the classification
process. We show on a diverse set of tasks that the use of appropriate sets of unlabeled background knowledge often decreases
error rates, particularly if the number of examples or the size of the strings in the training set is small. This is especially
useful when labeling text is a labor-intensive job and when there is a large amount of information available about a particular
problem on the World Wide Web.
相似文献
Haym HirshEmail: |
173.
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: |
174.
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: |
175.
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
176.
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
177.
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
178.
In Pavlovian fear conditioning, context-mediated decrements in conditioned responding (e.g., the US preexposure effect) can
counteract competition between cues trained together (e.g., overshadowing). Two experiments were conducted using rats in a
conditioned lick suppression preparation to determine whether context-mediated competition also counteracts competition between
cues trained separately (retroactive interference, or RI). In Experiment 1, a combination of degraded contingency and RI treatments
produced less of a decrement in conditioned responding than did either of those treatments alone. Experiment 2 showed that
RI treatment attenuates the normally deleterious effect of trial massing. The results suggest that empirical similarities
are shared by interference between cues trained apart and competition between cues trained together. 相似文献
179.
Islam MR Khandoker MA Afroz S Rahman MG Khan RI 《Journal of Zhejiang University. Science. B》2007,8(7):465-469
Goat ovaries were collected from the slaughterhouse and categorized as right, left, corpus luteum (CL)-present and -absent group and evaluated on the basis of weight (g), length (cm), width (cm), number of follicles, follicles aspirated and number and state ofcumulus-oocyte-complexes (COCs). Comparatively higher weight [(0.66±0.02) vs (0.64±0.02) g], length [(1.17±0.02) vs (1.1 ±0.02) cm] and width [(0.77±0.02) vs (0.74±0.02) cm] were found in right ovaries than those of left. On the other hand significantly (P〈0.05) higher weight [(0.71±0.03) vs (0.64±0.01) g] and width [(0.76±0.03) vs (0.75±0.01) cm] were found in CL-present group than those of CL-absent group of ovaries. The left ovaries contained comparatively higher number of normal COCs [(1.06±0.09) per ovary] than fight ovaries [(1.03±0.10) per ovary] and the similar trend was found in total number of follicles [(4.51±0.25) vs (4.30±0.23) per ovary] and follicles aspirated [(2.55±0.14) vs (2.52±0.12) per ovary]. But the total COCs per ovary was almost similar in both ovaries [right and left: (1.85±0.12) and (1.85±0.11) per ovary, respectively]. Higher number of total COCs [(1.87±0.09) vs (1.76±0.16) per ovary], total number of follicles [(4.45±0.19) vs (4.16±0.37) per ovary], follicles aspirated [(2.55±0.10) vs (2.48±0.21) per ovary] and normal COCs [(1.12±0.07) vs (0.76±0.14) per ovary] were found in CL-absent group than those of CL-present group of ovaries. 相似文献
180.
The perceived spatiotemporal continuity of objects depends on the way they appear and disappear as they move in the spatial layout. This study investigated whether infants' predictive tracking of a briefly occluded object is sensitive to the manner by which the object disappears and reappears. Five-, 7-, and 9-month-old infants were shown a ball rolling across a visual scene and briefly disappearing via kinetic occlusion, instantaneous disappearance, implosion, or virtual occlusion. Three different measures converged to show that predictive tracking increased with age and that infants were most likely to anticipate the reappearance of the ball following kinetic occlusion. These results suggest that infants' knowledge of the permanence and nonpermanence of objects is embodied in their predictive tracking. 相似文献