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941.
Citing statements can be used to aid retrieval, to increase the efficiency of citation indexes and for the study of information flow and use. These uses are only feasible on a large scale if computers can identify citing statements within the texts of documents with reasonable accuracy.Computer recognition of multi-sentence citing statements is not easy. Procedures developed for chemistry papers in an earlier experiment were tested on biomedical papers (dealing with various aspects of cancer) and were almost as successful. Specifically, (1) 78% of the words in computer-recognized citing statements were correctly attributable to the corresponding cited papers; and (2) the computer procedures missed 4% of the words in the actual citing statements. When the procedures were modified on the basis of those results and tested on a new sample of cancer papers the results were comparable: 72 and 3% respectively.In an earlier experiment in use of full-text searching to retrieve answer-passages from cancer papers, recall in the “test phase” averaged about 70% and the false retrieval rate was thirteen falsely retrieved sentences per answer-paper retrieved. Unretrieved answer-papers in that experiment's “development phase”, and citing statements referring to them, were studied to develop computer procedures for using citing statements to increase recall. The procedures developed only produced slight recall increases for development phase answer-papers, and similarly for the test phase papers on which they were then tested. Specifically, the test phase results were the following: recall was increased from 70 to 74%, and there was no increase in false retrieval. This contrasts with an earlier experiment in which 50% recall of chemistry papers by search of index terms and abstract words was increased to 70% by the addition of words from citing statements. The difference may be because the average number of citing papers per unretrieved cancer paper was only six while that for chemistry papers was thirteen. 相似文献
942.
943.
While there is no universal logic of induction, the probabilitycalculus succeeds as a logic of induction in many contexts throughits use of several notions concerning inductive inference. Theyinclude Addition, through which low probabilities representdisbelief as opposed to ignorance; and Bayes property, whichcommits the calculus to a refute and rescale dynamicsfor incorporating new evidence. These notions are independentand it is urged that they be employed selectively accordingto needs of the problem at hand. It is shown that neither isadapted to inductive inference concerning some indeterministicsystems.
- 1 Introduction
- 2 Failure of demonstrations of universality
- 2.1 Working backwards
- 2.2 The surface logic
- 3 Framework
- 3.1 The properties
- 3.2 Boundaries
- 3.2.1 Universalcomparability
- 3.2.2 Transitivity
- 3.2.3 Monotonicity
- 3.2.2 Transitivity
- 3.2 Boundaries
- 4 Addition
- 4.1 The property: disbelief versus ignorance
- 4.2Boundaries
- 5 Bayes property
- 5.1 The property
- 5.2 Bayes' theorem
- 5.3Boundaries
- 5.3.1 Dogmatism of the priors
- 5.3.2 Impossibilityof prior ignorance
- 5.3.3 Accommodation of virtues
- 5.3.2 Impossibilityof prior ignorance
- 5.2 Bayes' theorem
- 6Real values
- 7 Sufficiency and independence
- 8 Illustrations
- 8.1 All properties retained
- 8.2 Bayes propertyonly retained
- 8.3 Induction without additivity and Bayes property
- 8.2 Bayes propertyonly retained
- 9Conclusion
- 2 Failure of demonstrations of universality
944.
James G. Taylor 《Journal of The Franklin Institute》1981,311(3):151-170
New important battle-outcome-prediction conditions are developed for combat between two homogeneous military forces modelled by variable-coefficient Lanchester-type equations for area fire. Such conditions are very significant in modern operations research for developing important insights into the dynamics of combat. However, similar differential-equation models do arise in other fields of science and technology such as mathematical ecology and epidemiology, and consequently our new mathematical results may also find application there. These new important “simple approximate” battle-outcome-prediction conditions depend on not only the combat-attrition model but also the battle-termination model, and they are developed for two different types of battle-termination conditions (fixed-force-level-breakpoint battles and fixed-force-ratio-breakpoint battles). They are sufficient (but not necessary) to determine the outcome of battle without having to explicitly compute the force-level trajectories, and a generalization of Lanchester’s famous linear law to variable-coefficient combat is involved in their development. Certain integrability properties of the Lanchester attrition-rate coefficients figure prominently in these results, and an important physical interpretation (relating to logistics considerations) is given for these properties. 相似文献
945.
Simple as the outflow clock principle may seem for the measurement of time, its translation into an accurate clock raises formidable technical and conceptual problems. An attempt is made here to reconstruct the Egyptians' consciousness of these problems, and the success of their solutions. 相似文献
946.
James Hartley 《中国科技期刊研究》2004,15(2):127-129
参考文献表的编排有多种体例形式,并且不同体例中参考文献各著录项的表达也不尽相同。由于期刊大都倾向于采用自己所特定的参考文献著录格式,因而目前已有的参考文献软件并不能给予作者很多帮助,即作者如果将其稿件由某期刊改投到另一种期刊,通常需要改动其中的参考文献表格式和正文中的相关部分。在众多的参考文献表格式中,有两种最为主要。其一是在人文科学中较为常用的哈佛体系(即著者一出版年体系),该体系规定正文中给出引文的作者和出版年,文献书目中的引文按著者姓名的字母顺序和出版年的先后排列。另外一种主要的参考文献表是数字体系(顺序编码制),即正文中给出引文的序号,参考文献表中的各篇文献按其在正文中出现的先后顺序排列。科技论文和医学论文多采用该种体例。本文列举了上述两种体例的格式,并对比了二者的优缺点,认为著者.出版年体系可以使学术论文的读者很方便地了解作者所引用的工作是由谁完成的,而数字体系(顺序编码制)因为简洁,从而可以使读者更为通畅地阅读论文。 相似文献
947.
This paper investigates the conditions when a research joint venture (RJV) will involve a university as a research partner. We hypothesize that larger RJVs are more likely to invite a university to join the venture as a research partner than smaller RJVs because larger ventures are less likely to expect substantial additional appropriability problems to result because of the addition of a university partner and because the larger ventures have both a lower marginal cost and a higher marginal value from university R&D contributions to the ventures’ innovative output. We test this hypothesis using data from the COoperative REsearch (CORE) database, and those data confirm the hypothesis. 相似文献
948.
James L. Dolby 《Information processing & management》1977,13(1):69-77
One of the fundamental problems in information science is to distinguish various objects (such as books or journal articles) on the basis of associated values (such as authors and titles). Where the values fail to distinguish two distinct objects we say that the objects are ambigious under the given value assignment. To obtain a measure of ambiguity, it is only necessary to count the number of ways that the objects can be arranged for each set of ambiguous objects, multiply these counts and take logarithms. It is shown that such an approach leads to a measure in the formal sense and that the measure depends only on the definition of equality of values so that it can be simply extended to sets of values and ordered sets of values. It is also shown that it is possible to construct a function of ambiguity that one can call “information” and that the information loss that occurs when distinct values are grouped into equivalence classes (as in the use of search and sort keys) is also a measure. Finally, it is shown that ambiguity and information as here defined are directly related to Shannon's definition of “information” thus tieing this approach to that portion of information theory associated with the derivation of optimal distributions frequently used in information science models. 相似文献
949.
950.
Artificial Life (ALife) has two goals. One attempts to describe fundamental qualities of living systems through agent based
computer models. And the second studies whether or not we can artificially create living things in computational mediums that
can be realized either, virtually in software, or through biotechnology. The study of ALife has recently branched into two
further subdivisions, one is “dry” ALife, which is the study of living systems “in silico” through the use of computer simulations,
and the other is “wet” ALife that uses biological material to realize what has only been simulated on computers, effectively
wet ALife uses biological material as a kind of computer. This is challenging to the field of computer ethics as it points
towards a future in which computer and bioethics might have shared concerns. The emerging studies into wet ALife are likely
to provide strong empirical evidence for ALife’s most challenging hypothesis: that life is a certain set of computable functions
that can be duplicated in any medium. I believe this will propel ALife into the midst of the mother of all cultural battles
that has been gathering around the emergence of biotechnology. Philosophers need to pay close attention to this debate and
can serve a vital role in clarifying and resolving the dispute. But even if ALife is merely a computer modeling technique
that sheds light on living systems, it still has a number of significant ethical implications such as its use in the modeling
of moral and ethical systems, as well as in the creation of artificial moral agents. 相似文献