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1.
A bibliography is traditionally characterized by the judgments, bounded by explicit selection criteria, made by a single compiler. Because these criteria concern the attributes ascribed to a work and the needs of readers, bibliographic work is largely conceptual even across technological eras and domains. Yet, the development of networked information services, made possible by WWW infrastructure, has enabled very large numbers of people to discover, organize, and publish information, including bibliographies. Indeed, bibliographies, or at least bibliography-like artifacts, are a common genre of website, often published by people without specialized skills in information organization who follow non-rigorous selection procedures. Nevertheless, even if the items from these lists are poorly selected and described, this publishing activity is fundamentally important because it structures information locally, creating a patchy network of secondary access points. In turn, these access points enable information discovery, the formation and development of communities of interest, the estimation of document relevance by search engines, and so on. In sum, this activity, and the enabling technical infrastructure, invites bibliographies to take on new interactive possibilities. The aim of this article is to extend the traditional view of bibliography to encompass collaborative possibilities for wide, or narrow, participation in the shaping of bibliographies and the selection of items. This is done by examining the nature of bibliography on the Web, by proposing a conceptual model that opens bibliography to participatory practices, and by discussing a case study where a team sought to develop a bibliography of electronic resources. This examination reveals splendid opportunities for expanding the notion of bibliography with participatory policies while remaining true to its ancient roots. 相似文献
2.
The behavior of a class of hybrid systems in discrete-time can be represented by nonlinear difference equations with a Markov input. The analysis of such a system usually starts by establishing the Markov property of the joint process formed by combining the system's state and input. There are, however, no complete proofs of this property. This paper aims to address this problem by presenting a complete and explicit proof that uses only fundamental measure-theoretical concepts. 相似文献
3.
中国投资引致碳排放与经济增长的空间特征及脱钩测度 总被引：1，自引：0，他引：1
长期以来中国经济增长依赖投资,在低碳经济时代下,投资引致的碳排放和经济增长脱钩关系应受到关注。以往对此研究相对较少,且忽略了投资通过不同区域间产业联系所引发的间接脱钩。本文引入面积元并结合投入产出表以改进脱钩模型,研究了2007-2010年间全社会固定资产投资直接、间接引致的中国30个省区市碳排放和经济增长的空间特征及脱钩关系。结果显示：①大部分省份由投资引致的经济增长比碳排放略快,两者为弱脱钩关系;北京和上海实现强脱钩发展,内蒙古、宁夏等资源型省份多为扩张负脱钩;②投资直接引致农林牧渔业实现脱钩发展,建筑业和服务业的直接脱钩状态相对较差;工业投资引致不同区域各产业的间接负脱钩状态最多,服务业受其他行业投资间接影响多呈现负脱钩状态。低碳发展相关政策的制定应考虑地区间的经济联系和产业间的拉动作用,适当补偿承担高碳生产环节的地区,避免盲目发展可能转移大量碳排放的产业。 相似文献
4.
Filipe Mesquita Altigran S. da Silva Edleno S. de Moura Pável Calado Alberto H.F. Laender 《Information processing & management》2007
A vast amount of valuable information, produced and consumed by people and institutions, is currently stored in relational databases. For many purposes, there is an ever increasing demand for having these databases published on the Web, so that users can query the data available in them. An important requirement for this to happen is that query interfaces must be as simple and intuitive as possible. In this paper we present LABRADOR, a system for efficiently publishing relational databases on the Web by using a simple text box query interface. The system operates by taking an unstructured keyword-based query posed by a user and automatically deriving an equivalent SQL query that fits the user’s information needs, as expressed by the original query. The SQL query is then sent to a DBMS and its results are processed by LABRADOR to create a relevance-based ranking of the answers. Experiments we present show that LABRADOR can automatically find the most suitable SQL query in more than 75% of the cases, and that the overhead introduced by the system in the overall query processing time is almost insignificant. Furthermore, the system operates in a non-intrusive way, since it requires no modifications to the target database schema. 相似文献
5.
Document similarity search (i.e. query by example) aims to retrieve a ranked list of documents similar to a query document in a text corpus or on the Web. Most existing approaches to similarity search first compute the pairwise similarity score between each document and the query using a retrieval function or similarity measure (e.g. Cosine), and then rank the documents by the similarity scores. In this paper, we propose a novel retrieval approach based on manifold-ranking of document blocks (i.e. a block of coherent text about a subtopic) to re-rank a small set of documents initially retrieved by some existing retrieval function. The proposed approach can make full use of the intrinsic global manifold structure of the document blocks by propagating the ranking scores between the blocks on a weighted graph. First, the TextTiling algorithm and the VIPS algorithm are respectively employed to segment text documents and web pages into blocks. Then, each block is assigned with a ranking score by the manifold-ranking algorithm. Lastly, a document gets its final ranking score by fusing the scores of its blocks. Experimental results on the TDT data and the ODP data demonstrate that the proposed approach can significantly improve the retrieval performances over baseline approaches. Document block is validated to be a better unit than the whole document in the manifold-ranking process. 相似文献
6.
Kathrin Müller 《Research Policy》2010,39(2):189-12597
For academic spin-offs I analyze the length of the time period between the founder’s leaving of academia and the establishment of her firm. A duration analysis reveals that a longer time-lag is caused by the necessity of assembling complementary skills, either by acquisition by a single founder or by searching for suitable team members. Furthermore, new ventures are established faster if there has been high-level technology transfer, if the founders have access to university infrastructure, or if they receive informal support by former colleagues. 相似文献
7.
软技术作为一种限制不同操作者之间,以及操作者与工具之间进行协作的规则体系,改变了操作者决策依据和动作的发生方式,最终影响了操作者的学习效率;本文证实了软技术对操作者学习效率的影响:在同样任务条件下,在软技术的规范下,操作效率的改进时间,要短于自学习的方式;也就是在软技术作用下,操作效率将先达到比较稳定的高点,得到了证实;操作者效率改进过程发生了变化,操作效率改进曲线有突变,软技术明显地改变了效率改进曲线;而无软技术作用时,操作者效率改进是平缓的,无突变的。 相似文献
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9.
建立国际反垄断政策协调体制的尝试主要是由欧盟和美国推动的,欧盟希望整合国际反垄断法律并在WTO范围内执行,而美国则希望组成一个国际竞争网络(ICN)作为多边合作平台。通过比较,可以发现WTO和ICN途径之间同时又是互补的,这将导致两个体制的长期共存。 相似文献
10.
本文受文献[1]的启发,定义了方阵和矩阵之间的一类特殊的乘积,即方阵左乘到矩阵中的若干行或右乘到矩阵中的若干列。利用[1]中的定理1,证明了这种乘积的广义行列式所满足的一个等式。利用这个等式,给出Liouville公式的一个推广。 相似文献
11.
Motivation of software developers in Open Source projects: an Internet-based survey of contributors to the Linux kernel 总被引：2，自引：0，他引：2
The motives of 141 contributors to a large Open Source Software (OSS) project (the Linux kernel) was explored with an Internet-based questionnaire study. Measured factors were both derived from discussions within the Linux community as well as from models from social sciences. Participants’ engagement was particularly determined by their identification as a Linux developer, by pragmatic motives to improve own software, and by their tolerance of time investments. Moreover, some of the software development was accomplished by teams. Activities in these teams were particularly determined by participants’ evaluation of the team goals as well as by their perceived indispensability and self-efficacy. 相似文献
12.
《傲慢与偏见》是英国著名女作家简.奥斯汀的一部力作,描述的是青年男女恋爱与婚姻。本文作者试通过分析小说四起典型的婚姻来讨论性格是如何影响一个人的婚姻价值定位的,以及简.奥斯汀对待婚姻的看法;《金粉世家》中的男女主人公也是存在类似的命运,真挚的爱情受到世俗偏见的考验,爱情的力量是伟大的,二人很幸福地结合了,然而最终作者却是以悲剧结局了整部作品。两部作品的爱情与婚姻相同而又具有差异性。 相似文献
13.
习惯性或忠诚性购买行为下的新产品扩散 总被引：8，自引：0，他引：8
消费者习惯性或忠诚性购买行为对新产品扩散有阻滞作用，从而影响Bass模型在非垄断情况下的应用。在一定条件下通过构建反映这种行为的顾客期望状态转移矩阵，利用惯性系数对Bass宏观创新采用概率做出修正，得出了惯性购买行为下的新产品扩散模型。 相似文献
14.
郑州大学知识库建设和实施的方法 总被引：1，自引：0，他引：1
机构知识库是一个大学或研究机构通过网络来收集、存储、管理、检索其产生的学术成果并提供开放服务数据库系统。在促进大学学术成果的保存、传播与利用及为大学的学术成就树立品牌方面起着重要作用。本文探讨了"郑州大学知识库"系统平台建设和实施方法,并提出自己的建议。 相似文献
15.
On the web, a huge variety of text collections contain knowledge in different expertise domains, such as technology or medicine. The texts are written for different uses and thus for people having different levels of expertise on the domain. Texts intended for professionals may not be understandable at all by a lay person, and texts for lay people may not contain all the detailed information needed by a professional. Many information retrieval applications, such as search engines, would offer better user experience if they were able to select the text sources that best fit the expertise level of the user. In this article, we propose a novel approach for assessing the difficulty level of a document: our method assesses difficulty for each user separately. The method enables, for instance, offering information in a personalised manner based on the user’s knowledge of different domains. The method is based on the comparison of terms appearing in a document and terms known by the user. We present two ways to collect information about the terminology the user knows: by directly asking the users the difficulty of terms or, as a novel automatic approach, indirectly by analysing texts written by the users. We examine the applicability of the methodology with text documents in the medical domain. The results show that the method is able to distinguish between documents written for lay people and documents written for experts. 相似文献
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17.
Demand is a major potential source of innovation, yet the critical role of demand as a key driver of innovation has still to be recognised in government policy. This article discusses public procurement as one of the key elements of a demand-oriented innovation policy. The paper starts by signaling the new significance of public procurement for innovation policy strategies at the EU level and in a range of European countries. It then defines the concept of public procurement and embeds this concept within a taxonomy of innovation policies. The rationales and justifications of public procurement policies to spur innovation are discussed, followed by a consideration of the challenges and potential pitfalls as well as appropriate institutional arrangements and strategies, including some recent empirical examples of good practice. It concludes by confronting the public procurement approach with two of the most common objections to it and by considering future prospects. 相似文献
18.
In this paper, we propose a continuous flow droplet-based microfluidic platform for magnetic particle-based assays by employing in-droplet washing. The droplet-based washing was implemented by traversing functionalized magnetic particles across a laterally merged droplet from one side (containing sample and reagent) to the other (containing buffer) by an external magnetic field. Consequently, the magnetic particles were extracted to a parallel-synchronized train of washing buffer droplets, and unbound reagents were left in an original train of sample droplets. To realize the droplet-based washing function, the following four procedures were sequentially carried in a droplet-based microfluidic device: parallel synchronization of two trains of droplets by using a ladder-like channel network; lateral electrocoalescence by an electric field; magnetic particle manipulation by a magnetic field; and asymmetrical splitting of merged droplets. For the stable droplet synchronization and electrocoalescence, we optimized droplet generation conditions by varying the flow rate ratio (or droplet size). Image analysis was carried out to determine the fluorescent intensity of reagents before and after the washing step. As a result, the unbound reagents in sample droplets were significantly removed by more than a factor of 25 in the single washing step, while the magnetic particles were successfully extracted into washing buffer droplets. As a proof-of-principle, we demonstrate a magnetic particle-based immunoassay with streptavidin-coated magnetic particles and fluorescently labelled biotin in the proposed continuous flow droplet-based microfluidic platform. 相似文献
19.
Alistair Black 《The Information Society》2001,17(1):63-80
Contrary to the "retro" image often awarded them, and despite their continuing enthusiasm and responsibility for the organization of printed materials, librarians are upbeat about the prospects of an information society driven primarily by electronic technologies, but in which libraries can play an important part. Public librarians detect a natural correlation between the historic democratic mission of their institution and the increased accessibility made possible by digitalized sources. The library community's acceptance of the information society idea as a "given" social phenomenon supports discourses that play down historical continuities and herald the dawn of a new age. Such discourses ignore or reject historical evidence that points to the existence of past information societies, revolutions, and infrastructures defined, in part, by the operation of indirect surveillance, constituted by the bureaucratic information systems of modernity. Victorian Britain serves as a good example of an early information society, to which public libraries, themselves micro-information societies, contributed significantly. The role played by public librarians in the Victorian information society, illustrated in this article by evidence drawn from the contemporary library press, is seen in their preoccupation with the surveillance and ordering of knowledge; their adoption for library operations of the businesslike, bureaucratic procedures described recently by business historians; and their panoptic tracking of users and their activities. 相似文献
20.
张砺 《科技成果管理与研究》2009,(8):89-90,103
膜结构是近40年发展起来的一种新型建筑结构形式,它以性能优良的柔软织物作为覆盖材料,可以是向膜内充空气,由空气压力支撑膜面,也可以利用柔软的拉索结构或刚性的支撑结构将膜绷紧或撑起,从而形成具有一定刚度、能够覆盖大跨度空间的结构体系。膜结构的突出特点就是它形状的多样性．曲面存在着无限的可能性。以索或骨架支承的膜结构．其曲面就可以随着建筑师的想象力而任意变化,使得膜结构具有广阔的发展前景,将是21世纪空间结构发展的主流。 相似文献