Web链接结构信息研究综述

万维网（World Wide Web）是由大量的网页组成的，网页之间由超链接（HyperLink）相互连接。在传统上，人们对网络信息的分析和获取是依靠对网页内容的分析和处理来进行的。例如，传统的网络搜索引擎对网页上文本信息进行分析、索引，并将处理后的信息存储在数据库中，然后根据用户查询输入进行分析，获得查询结果。

Rapid world wide depletion of predatory fish communities

Serious concerns have been raised about the ecological effects of industrialized fishing1, 2, 3, spurring a United Nations resolution on restoring fisheries and marine ecosystems to healthy levels4. However, a prerequisite for restoration is a general understanding of the composition and abundance of unexploited fish communities, relative to contemporary ones. We constructed trajectories of community biomass and composition of large predatory fishes in four continental shelf and nine oceanic systems, using all available data from the beginning of exploitation. Industrialized fisheries typically reduced community biomass by 80% within 15 years of exploitation. Compensatory increases in fast-growing species were observed, but often reversed within a decade. Using a meta-analytic approach, we estimate that large predatory fish biomass today is only about 10% of pre-industrial levels. We conclude that declines of large predators in coastal regions5 have extended throughout the global ocean, with potentially serious consequences for ecosystems5, 6, 7. Our analysis suggests that management based on recent data alone may be misleading, and provides minimum estimates for unexploited communities, which could serve as the ‘missing baseline’8 needed for future restoration efforts.

Web数据挖掘的原理、方法及用途

Web数据挖掘是将数据挖掘技术和理论应用于对WWW资源进行挖掘的一个新兴的研究领域,本文介绍了Web数据挖掘的基本概念,分类,并给出 Web数据挖掘的基本原理,基本方法,最后指出 Web数据挖掘的用途,展望了其美好的发展前景。

World-wide evangelization the urgent business of the church; addresses delivered before the fourth international convention of the Student volunteer movement for foreign missions, Toronto, Canada, February 26-March 2, 1902.

http://www.archive.org/details/worldwideevangel00unknuoft

Resource Management for Responsive Web Computing

The exploding demand for services like the World Wide Web reflects the potential that is presented by globally distributed information systems. The number of WWW servers world-wide has doubled every 3 to 5 months since 1993, outstripping even the growth of the Internet. At each of these self-managed sites, the Common Gateway Interface (CGI) and Hypertext Transfer Protocol (HTTP) already constitute a rudimentary basis for contributing local resources to remote collaborations. However, the Web has serious deficiencies that make it unsuited for use as a true medium for metacomputing --- the process of bringing hardware, software, and expertise from many geographically dispersed sources to bear on large scale problems. These deficiencies are, paradoxically, the direct result of the very simple design principles that enabled its exponential growth. There are many symptoms of the problems exhibited by the Web: disk and network resources are consumed extravagantly; information search and discovery are difficult; protocols are aimed at data movement rather than task migration, and ignore the potential for distributing computation. However, all of these can be seen as aspects of a single problem: as a distributed system for metacomputing, the Web offers unpredictable performance and unreliable results. The goal of our project is to use the Web as a medium (within either the global Internet or an enterprise intranet) for metacomputing in a reliable way with performance guarantees. We attack this problem one four levels: (1) Resource Management Services: Globally distributed computing allows novel approaches to the old problems of performance guarantees and reliability. Our first set of ideas involve setting up a family of real-time resource management models organized by the Web Computing Framework with a standard Resource Management Interface (RMI), a Resource Registry, a Task Registry, and resource management protocols to allow resource needs and availability information be collected and disseminated so that a family of algorithms with varying computational precision and accuracy of representations can be chosen to meet realtime and reliability constraints. (2) Middleware Services: Complementary to techniques for allocating and scheduling available resources to serve application needs under realtime and reliability constraints, the second set of ideas aim at reduce communication latency, traffic congestion, server work load, etc. We develop customizable middleware services to exploit application characteristics in traffic analysis to drive new server/browser design strategies (e.g., exploit self-similarity of Web traffic), derive document access patterns via multiserver cooperation, and use them in speculative prefetching, document caching, and aggressive replication to reduce server load and bandwidth requirements. (3) Communication Infrastructure: Finally, to achieve any guarantee of quality of service or performance, one must get at the network layer that can provide the basic guarantees of bandwidth, latency, and reliability. Therefore, the third area is a set of new techniques in network service and protocol designs. (4) Object-Oriented Web Computing Framework A useful resource management system must deal with job priority, fault-tolerance, quality of service, complex resources such as ATM channels, probabilistic models, etc., and models must be tailored to represent the best tradeoff for a particular setting. This requires a family of models, organized within an object-oriented framework, because no one-size-fits-all approach is appropriate. This presents a software engineering challenge requiring integration of solutions at all levels: algorithms, models, protocols, and profiling and monitoring tools. The framework captures the abstract class interfaces of the collection of cooperating components, but allows the concretization of each component to be driven by the requirements of a specific approach and environment.

Changes in Web Client Access Patterns: Characteristics and Caching Implications

Understanding the nature of the workloads and system demands created by users of the World Wide Web is crucial to properly designing and provisioning Web services. Previous measurements of Web client workloads have been shown to exhibit a number of characteristic features; however, it is not clear how those features may be changing with time. In this study we compare two measurements of Web client workloads separated in time by three years, both captured from the same computing facility at Boston University. The older dataset, obtained in 1995, is well-known in the research literature and has been the basis for a wide variety of studies. The newer dataset was captured in 1998 and is comparable in size to the older dataset. The new dataset has the drawback that the collection of users measured may no longer be representative of general Web users; however using it has the advantage that many comparisons can be drawn more clearly than would be possible using a new, different source of measurement. Our results fall into two categories. First we compare the statistical and distributional properties of Web requests across the two datasets. This serves to reinforce and deepen our understanding of the characteristic statistical properties of Web client requests. We find that the kinds of distributions that best describe document sizes have not changed between 1995 and 1998, although specific values of the distributional parameters are different. Second, we explore the question of how the observed differences in the properties of Web client requests, particularly the popularity and temporal locality properties, affect the potential for Web file caching in the network. We find that for the computing facility represented by our traces between 1995 and 1998, (1) the benefits of using size-based caching policies have diminished; and (2) the potential for caching requested files in the network has declined.

A concept analysis of renal supportive care: the changing world of nephrology

Title. A concept analysis of renal supportive care: the changing world of nephrology

Aim. This paper is a report of a concept analysis of renal supportive care.

Background. Approximately 1.5 million people worldwide are kept alive by renal dialysis. As services are required to support patients who decide not to start or to withdraw from dialysis, the term renal supportive care is emerging. Being similar to the terms palliative care, end-of-life care, terminal care and conservative management, there is a need for conceptual clarity.

Method. Rodgers' evolutionary method was used as the organizing framework for this concept analysis. Data were collected from a review of CINAHL, Medline, PsycINFO, British Nursing Index, International Bibliography of the Social Sciences and ASSIA (1806-2006) using, 'renal' and 'supportive care' as keywords. All articles with an abstract were considered. The World Wide Web was also searched in English utilizing the phrase 'renal supportive care'.

Results. Five attributes of renal supportive care were identified: available from diagnosis to death with an emphasis on honesty regarding prognosis and impact of disease; interdisciplinary approach to care; restorative care; family and carer support and effective, lucid communication to ensure informed choice and clear lines of decision-making.

Conclusion. Renal supportive care is a dynamic and emerging concept relevant, but not limited to, the end phase of life. It suggests a central philosophy underpinning renal service development that allows patients, carers and the multidisciplinary team time to work together to realize complex goals. It has relevance for the renal community and is likely to be integrated increasingly into everyday nephrology practice.

Reasoning about orchestrations of web services using partial correctness

A service is a remote computational facility which is made available for general use by means of a wide-area network. Several types of service arise in practice: stateless services, shared state services and services with states which are customised for individual users. A service-based orchestration is a multi-threaded computation which invokes remote services in order to deliver results back to a user (publication). In this paper a means of specifying services and reasoning about the correctness of orchestrations over stateless services is presented. As web services are potentially unreliable the termination of even finite orchestrations cannot be guaranteed. For this reason a partial-correctness powerdomain approach is proposed to capture the semantics of recursive orchestrations.

A web-based overview of semiconductor photochemistry-based current commercial applications

The major current commercial applications of semiconductor photochemistry promoted on the world wide web are reviewed. The basic principles behind the different applications are discussed, including the use of semiconductor photochemistry to: photo-mineralise organics, photo-sterilise and photo-demist. The range of companies, and their products, which utilise semiconductor photochemistry are examined and typical examples listed. An analysis of the geographical distribution of current commercial activity in this area is made. The results indicate that commercial activity in this area is growing world-wide, but is especially strong in Japan. The number and geographical distribution of patents in semiconductor photocatalysis are also commented on. The trends in the numbers of US and Japanese patents over the last 6 years are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.

Visually extracting data records from the deep web

Web sites that rely on databases for their content are now ubiquitous. Query result pages are dynamically generated from these databases in response to user-submitted queries. Automatically extracting structured data from query result pages is a challenging problem, as the structure of the data is not explicitly represented. While humans have shown good intuition in visually understanding data records on a query result page as displayed by a web browser, no existing approach to data record extraction has made full use of this intuition. We propose a novel approach, in which we make use of the common sources of evidence that humans use to understand data records on a displayed query result page. These include structural regularity, and visual and content similarity between data records displayed on a query result page. Based on these observations we propose new techniques that can identify each data record individually, while ignoring noise items, such as navigation bars and adverts. We have implemented these techniques in a software prototype, rExtractor, and tested it using two datasets. Our experimental results show that our approach achieves significantly higher accuracy than previous approaches. Furthermore, it establishes the case for use of vision-based algorithms in the context of data extraction from web sites.

The Multiple Facets of ETF Investing: A World-Wide Analysis

The global ETF industry provides more complicated investment vehicles than low-cost index trackers. Instead, we find that the real investments of ETFs that do not fully replicate their benchmarks may deviate from their benchmarks to leverage informational advantages (which leads to a surprising stock-selection ability), to benefit from the securities lending market, to support ETF-affiliated banks’ stock prices, and to help affiliated OEFs through cross-trading. These effects are more prevalent in ETFs domiciled in Europe. Market awareness of such additional risk is reflected in ETF outflows. These results have important normative implications for consumer protection and financial stability.

Evaluation of information extraction techniques to label extracted data from e-commerce web page

Automatically determining and assigning shared and meaningful text labels to data extracted from an e-Commerce web page is a challenging problem. An e-Commerce web page can display a list of data records, each of which can contain a combination of data items (e.g. product name and price) and explicit labels, which describe some of these data items. Recent advances in extraction techniques have made it much easier to precisely extract individual data items and labels from a web page, however, there are two open problems: 1. assigning an explicit label to a data item, and 2. determining labels for the remaining data items. Furthermore, improvements in the availability and coverage of vocabularies, especially in the context of e-Commerce web sites, means that we now have access to a bank of relevant, meaningful and shared labels which can be assigned to extracted data items. However, there is a need for a technique which will take as input a set of extracted data items and assign automatically to them the most relevant and meaningful labels from a shared vocabulary. We observe that the Information Extraction (IE) community has developed a great number of techniques which solve problems similar to our own. In this work-in-progress paper we propose our intention to theoretically and experimentally evaluate different IE techniques to ascertain which is most suitable to solve this problem.

A presença empresarial online e a incorporação de tendências Web 2.0

Numa época marcada pelas novas tecnologias da comunicação e informação, o sector empresarial debate-se com a necessidade de marcar a diferença. Inovar na forma de contactar o cliente (ou possível cliente) e promover a sua marca são objectivos ambicionados pelas empresas ao investirem na sua representação online. Na Web 2.0 a partilha de informação, a instantaneidade nos contactos, o feedback imediato e a proximidade (aparente) são levados ao extremo e apresentam-se como argumentos capazes de suscitar alterações profundas ao nível das estratégias de comunicação empresarial online. Abordando as mais recentes tendências e ferramentas da Web 2.0 na presença online das organizações, recorrendo a revisão bibliográfica alargada, à aplicação e análise de inquéritos por questionário e à observação de presenças organizacionais na World Wide Web, neste estudo procura-se compreender “como estão as empresas nacionais a integrar, na sua presença online, características / ferramentas da Web 2.0”. ABSTRACT: In an era marked by new technologies of information and communication, the business sector has to contend with the need to make the difference. Innovating in the manner of contacting a (possible) client and promoting their brand is a companyʼs desired objective when investing in their online presence. In Web 2.0, the share of information, the instant contact, the immediate feedback and (apparent) proximity are taken to the extreme and are presented as arguments capable of modifying strategies related with a businessʼs online communication. Exploring the latest trends and tools of Web 2.0 in the online representation of organizations, as well as the use of an extended literature review, the application and analysis of surveys and the observation of organizational presences on the World Wide Web; this study seeks to understand "in what way are national companies integrating in their online presence features/tools of the Web 2.0".

Gestão de informação académica com base na Web: um sistema de apoio a programas de pós-graduação

Esta dissertação descreve o processo de desenvolvimento de um sistema de informação para a gestão da informação académica de programas de pósgraduação - Sistema WebMaster - que tem como objectivo tornar aquela informação acessível aos utilizadores através da World Wide Web (WWW). Começa-se por apresentar alguns conceitos que se julgam relevantes para a compreensão da problemática dos sistemas de informação em toda a sua abrangência numa determinada organização, particularizando alguns conceitos para o caso das universidades. De seguida reflecte-se sobre os sistemas de informação com base na Web, confrontando-se os conceitos de Web Site (tradicional) e aplicação Web, a nível de arquitectura tecnológica, principais vantagens e desvantagens, fazendo-se, ainda, uma breve referência às principais tecnologias para a construção de soluções com geração dinâmica de conteúdos. Por último representa-se o sistema WebMaster ao longo das suas diferentes etapas de desenvolvimento, desde a análise de requisitos, projecto do sistema, até à fase da implementação. A fase análise de requisitos foi levada a cabo através de um inquérito realizado aos potenciais utilizadores no sentido de identificar as suas necessidades de informação. Com base nos resultados desta fase apresenta-se o projecto do sistema numa perspectiva conceptual, navegacional e de interface de utilizador, fazendo uso da metodologia OOHDM - Object-Oriented Hypermedia Design Method. Finalmente, passa-se à fase da implementação que, com base nas etapas anteriores e nas tecnologias seleccionadas na fase do planeamento, proporciona um espaço interactivo e de troca de informação a todos os interessados da comunidade académica envolvidos em cursos de pós-graduação.

Web-Atlas Konsumgüterwirtschaft

Verzeichnis und Portrait von relevanten Webseiten im Themenfeld "Konsumgüterwirtschaft".