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1.
When public catalog users enter queries that exactly match the catalog's controlled vocabulary, online systems should respond with browsing lists of alphabetically arranged subject headings, because such displays guide users to retrievals based on the assignment of the matched subject headings to bibliographic records. Unfortunately, studies of online catalog searching demonstrate that alphabetical displays are no longer capable of managing large numbers of subdivided forms of subject headings, because searchers exhibit low levels of perseverance when faced with large numbers of retrievals. This paper introduces a new approach to displaying retrieved subject headings in subject searching—the exact-display approach—designed to encourage users to browse bibliographic information. The purpose of this paper is to emphasize the importance of the exact-display approach by showing how many user queries would be candidates for this approach, demonstrate an implementation of the exact-display approach in an experimental online catalog, and feature end-user experiences with this approach as implemented in the experimental catalog. End-user experiences gave the authors the opportunity to make several recommendations for enhancing the original design of the exact-display approach so that future implementations of this approach in operational online catalogs are responsive to the needs of online catalog users. 相似文献
2.
Justine Roberts 《Information processing & management》1983,19(3):131-139
The national standard machine-readable bibliographic format for films was expanded and modified for use in cataloging a collection of medical illustrations at the University of California, San Francisco. SNOMED and MeSH subject terms are stored in the computer catalog records and used to produce precoordinated entry terms for an Anatomic Index and a Disease/Procedures Index to the collection. 相似文献
3.
《Information processing & management》2019,56(3):823-843
A vast number of user opinions are available from reviews posted on e-commerce websites. Although these opinions are a valuable source of knowledge for both manufacturers and customers, they provide volumes of information that exceeds the human cognitive processing capacity, which can be a major bottleneck for their effective use. To address this problem, a number of opinion-summarization methods have been proposed to organize these opinions by grouping them around aspects. However, these methods tend to generate an excessive number of aspect groups that are frequently overly generic and difficult to interpret. We argue that a superior alternative would be to organize opinions around product attributes as defined in a product catalog. Typically, product attributes correspond to the most important characteristics of the products. Furthermore, they are common to all products in a given category and thus, form a more stable set than aspects. In this paper, we propose a novel approach called OpinionLink to products in a catalog at the attribute granularity level with opinions extracted from product reviews. The proposed approach is divided into two phases. In the first phase, OpinionLink uses a classifier to identify opinionated sentences in the reviews on a particular product. In the second phase, another classifier is used to map the opinions that were previously extracted from the user reviews to the attributes of the products in the product catalog. We performed a series of experiments on these phases. For the first phase, our experiments indicated that using classifiers with the proposed features achieved an average of 0.87 in terms of F1 measure for the task of identifying opinionated sentences. In the second phase, the method we proposed for the opinion-mapping task achieved an average of 0.85 in terms of F1. Further, we verified the effectiveness of the proposed approach as a realistic end-to-end application, indicating that we can use OpinionLink in a real setting. Finally, we empirically demonstrate the feasibility of using the proposed approach with an extremely large volume of opinions available in a collection of more than 600,000 real reviews. We also set forth a number of directions for future research. 相似文献
4.
This paper investigates entry guidance of a capsule for pinpoint landing on Mars. In this scenario, the capsule is subject to the external disturbances caused by the atmosphere that can result in control saturation, and then undesired landing errors. To this end, a new guidance scheme to satisfy entry constraints, high-accuracy landing at high elevation sites, is proposed. The technical contributions of this work are two-fold: first, in order to mitigate the effects caused by large disturbance, a function describing the joint constraints of bank angle and slacked height is proposed; based on the nonlinear model predictive control (NMPC), a new algorithm is developed, where the constraints of dynamics, bank angle, slacked height, are sufficiently considered and precisely modeled; second, a state-space observer to improve the prediction of disturbance is introduced, which can significantly improve the accuracy of landing performance. The numerical simulations show the feasibility and validity of the proposed scheme. 相似文献
5.
Johanna Pedroza-Díaz Sarah R?thlisberger 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2015,25(1):22-35
The discovery of protein biomarkers that reflect the biological state of the body is of vital importance to disease management. Urine is an ideal source of biomarkers that provides a non-invasive approach to diagnosis, prognosis and prediction of diseases. Consequently, the study of the human urinary proteome has increased dramatically over the last 10 years, with many studies being published. This review focuses on urinary protein biomarkers that have shown potential, in initial studies, for diseases affecting the urogenital tract, specifically chronic kidney disease and prostate cancer, as well as other non-urogenital pathologies such as breast cancer, diabetes, atherosclerosis and osteoarthritis. PubMed was searched for peer-reviewed literature on the subject, published in the last 10 years. The keywords used were “urine, biomarker, protein, and/or prostate cancer/breast cancer/chronic kidney disease/diabetes/atherosclerosis/osteoarthritis”. Original studies on the subject, as well as a small number of reviews, were analysed including the strengths and weaknesses, and we summarized the performance of biomarkers that demonstrated potential. One of the biggest challenges found is that biomarkers are often shared by several pathologies so are not specific to one disease. Therefore, the trend is shifting towards implementing a panel of biomarkers, which may increase specificity. Although there have been many advances in urinary proteomics, these have not resulted in similar advancements in clinical practice due to high costs and the lack of large data sets. In order to translate these potential biomarkers to clinical practice, vigorous validation is needed, with input from industry or large collaborative studies.Key words: urine, protein, biomarker 相似文献
6.
采用文献计量方法,对国内学习共享空间研究领域论文的时间分布、著者分布、期刊分布、关键词词频分布、基金论文分布及主题分布进行了定量分析,以考察这一领域研究现状,为今后研究作出参考。 相似文献
7.
本文通过分析4个尝试网络书目控制的站内搜索引擎的功能和存在的不足,从网页书目控制标签的制作、互联网目录的建立、目录过滤垃圾信息的功能提出改进的办法,并探讨网络书目控制搜索引擎工作原理和要达到的效果. 相似文献
8.
Uddin Md. Elmarhomy Elsayed Masao Kazuhiro Jun-ichi 《Information processing & management》2007,43(6):1793
Field Association (FA) terms are a limited set of discriminating terms that can specify document fields. Document fields can be decided efficiently if there are many relevant FA terms in that documents. An earlier approach built FA terms dictionary using a WWW search engine, but there were irrelevant selected FA terms in that dictionary because that approach extracted FA terms from the whole documents. This paper proposes a new approach for extracting FA terms using passage (portions of a document text) technique rather than extracting them from the whole documents. This approach extracts FA terms more accurately than the earlier approach. The proposed approach is evaluated for 38,372 articles from the large tagged corpus. According to experimental results, it turns out that by using the new approach about 24% more relevant FA terms are appending to the earlier FA term dictionary and around 32% irrelevant FA terms are deleted. Moreover, precision and recall are achieved 98% and 94% respectively using the new approach. 相似文献
9.
Martin Halvey David ValletDavid Hannah Yue FengJoemon M. Jose 《Information processing & management》2010
There are a number of multimedia tasks and environments that can be collaborative in nature and involve contributions from more than one individual. Examples of such tasks include organising photographs or videos from multiple people from a large event, students working together to complete a class project, or artists and/or animators working on a production. Despite this, current state of the art applications that have been created to assist in multimedia search and organisation focus on a single user searching alone and do not take into consideration the collaborative nature of a large number of multimedia tasks. The limited work in collaborative search for multimedia applications has concentrated mostly on synchronous, and quite often co-located, collaboration between persons. However, these collaborative scenarios are not always practical or feasible. In order to overcome these shortcomings we have created an innovative system for online video search, which provides mechanisms for groups of users to collaborate both asynchronously and remotely on video search tasks. In order to evaluate our system an user evaluation was conducted. This evaluation simulated multiple conditions and scenarios for collaboration, varying on awareness, division of labour, sense making and persistence. The outcome of this evaluation demonstrates the benefit and usability of our system for asynchronous and remote collaboration between users. In addition the results of this evaluation provide a comparison between implicit and explicit collaboration in the same search system. 相似文献
10.
基于Z39.50的虚拟联合目录体系概念模型 总被引：6，自引：0，他引：6
本文根据传统集中式联合目录存在的问题,在介绍分析Z39.50标准及其运行过程的基础上,对基于Z39.50标准的虚拟化和分布式联台目录系统的基本概念模式、广播式检索机制、编目联合作业和馆际互借联合作业方式等进行了初步探讨。 相似文献
11.
网络信息分类检索问题研究 总被引：4，自引：0，他引：4
This paper studies network information classification retrieval from the theory of information management. With a brief introduction to search engines, it focuses on analyzing the characteristics of network documents and their classification system. Problems in network document classification are pointed out. Suggestions such as constructing a catalog classification search engine system are made. 相似文献
12.
本文以SCIE收录的关于学科信息服务的学术文献为数据源,采用文献计量的方法,对学术文献的时间分布、学科分布、国家/地区分布及研究机构分布等外部特征方面进行统计,分析国际学科信息服务研究的基本态势;并利用HistCite、SPSS和Ucinet可视化工具对学科信息服务相关文献进行聚类分析和可视化显示,揭示出国际学科信息服务功能的发展轨迹、研究热点及前沿趋势,以期为现阶段学科信息服务研究工作的深入开展提供参考。 相似文献
13.
14.
《Information processing & management》2005,41(5):1193-1205
This paper examines a real-time measure of bias in Web search engines. The measure captures the degree to which the distribution of URLs, retrieved in response to a query, deviates from an ideal or fair distribution for that query. This ideal is approximated by the distribution produced by a collection of search engines. Differences between bias and classical retrieval measures are highlighted by examining the possibilities for bias in four extreme cases of recall and precision. The results of experiments examining the influence on bias measurement of subject domains, search engines, and search terms are presented. Three general conclusions are drawn: (1) the performance of search engines can be distinguished with the aid of the bias measure; (2) bias values depend on the subject matter under consideration; (3) choice of search terms does not account for much of the variance in bias values. These conclusions underscore the need to develop “bias profiles” for search engines. 相似文献
15.
《Research Policy》1999,28(2-3):179-193
This paper examines motives, location characteristics, inter-temporal characteristics and modes of entry for foreign direct investment (FDI) in research and development (R&D). The paper is based on a detailed empirical survey of laboratory sites established by 32 large multinational companies domiciled in 5 countries. Findings indicate that FDI in R&D has risen considerably over the last 40 years and that firms invest in R&D sites abroad in order to augment their knowledge base or in order to exploit it. The former motive leads to establishment of facilities primarily close to universities while the latter type leads to establishment of facilities close to existing manufacturing facilities and markets. The paper also finds that greenfield investments are the dominant mode of entry and that firms establish multiple R&D sites in their home countries before investing in such sites abroad. 相似文献
16.
寻找各学科居前1‰高被引论文的阈值,是评估科研绩效的标尺。利用中国知网检索了94个学科领域的居前1‰高被引论文,对被引用阈值和权重进行排序,发现各学科领域的阈值严重不均衡,最高值和最低值之间相差55倍,平均阈值为101。各学科阈值的高低取决于以下因素:文献总量多的学科领域高于文献总量少的学科领域;哲学与人文社会科学同一学科内基础理论领域高于其他领域等。 相似文献
17.
本文将2008-2011年中国科技部企业创新数据库、世界银行全球治理数据库和Hofstede关于文化的研究数据合并，基于东道国视角，研究东道国正式制度和文化制度对全球知识搜索与创新绩效关系的调节作用。实证结果表明外部知识搜索促进了企业创新绩效，前人提出的倒U型关系曲线的“拐点”尚未出现。进一步结合东道国制度因素对其探讨，发现东道国正式制度中的法律规则与监管质量负向调节搜索行为与创新绩效的关系；而文化制度中的长期导向正向调节二者之间的关系，权力距离的负向调节作用未出现。此外，我们还发现在上述东道国制度调节下全球知识搜索所实现的中国企业创新，仍以渐进式创新为主，颠覆式创新则略显乏力。 相似文献
18.
Michael J. Nelson 《Information processing & management》1997,33(6):739-744
A prefix trie index (originally called trie hashing) is applied to the problem of providing fast search times, fast load times and fast update properties in a bibliographic or full text retrieval system. For all but the largest dictionaries a single key search in the dictionary under trie hashing takes exactly one disk read. Front compression of search keys is used to enhance performance. Partial combining of the postings into the dictionary is analyzed as a method to give both faster retrieval and improved update properties for the trie hashing inverted file. Statistics are given for a test database consisting of an online catalog at the Graduate School of Library and Information Science Library of the University of Western Ontario. The effect of changing various parameters of prefix tries are tested in this application. 相似文献
19.
《Information processing & management》2001,37(5):721-740
This paper studies the influence of question-related variables (closed/open and predictable/unpredictable source) on Web users’ choices of search strategy (direct address, subject directory, and search engine) in the initial stage of a search. Subjects are 54 Finnish and American students with about 2.5 yr of Web searching. Data were gathered via a questionnaire asking for decisions for 16 questions of four types: closed/predictable source; closed/unpredictable source; open/predictable source; open/unpredictable source. The participants not only indicated a fairly high degree of familiarity with the initial search options and used different search strategies but also were influenced in their choice of an initial search strategy by question-related characteristics. Of the two question characteristics in the study, the most influential is the predictable/unpredictable source of the answer. The participants mentioned 24 different types of reasons for selecting the initial search strategy, which were grouped by their focus on questions, sources, and search strategy options. The reasons varied across question types. A model of choice behavior shows relationships among the initial question, the reasons, and the choice of initial search strategies. 相似文献
20.
Oscar H. GandyJr. 《Ethics and Information Technology》2010,12(1):29-42
In the future systems of ambient intelligence will include decision support systems that will automate the process of discrimination
among people that seek entry into environments and to engage in search of the opportunities that are available there. This
article argues that these systems must be subject to active and continuous assessment and regulation because of the ways in
which they are likely to contribute to economic and social inequality. This regulatory constraint must involve limitations
on the collection and use of information about individuals and groups. The article explores a variety of rationales or justifications
for establishing these limits. It emphasizes the unintended consequences that flow from the use of these systems as the most
compelling rationale. 相似文献