Over the past several years, a number of information discovery and access tools have been introduced in the Internet, including Archie, Gopher, Netfind, and WAIS. These tools have become quite popular, and are helping to redefine how people think about wide-area network applications. Yet, they are not well suited to supporting the future information infrastructure, which will be characterized by enormous data volume, rapid growth in the user base, and burgeoning data diversity. In this paper we indicate trends in these three dimensions and survey problems these trends will create for current approaches. We then suggest several promising directions of future resource discovery research, along with some initial results from projects carried out by members of the Internet Research Task Force Research Group on Resource Discovery and Directory Service.

Abstract: We provide an overview of the Garlic project, a new project at the IBM Almaden Research Center. The goal of this project is to develop a system and associated tools for the management of large quantities of heterogeneous multimedia information. Garlic permits traditional and multimedia data to be

Discovering different types of file resources (such as documentation, programs, and images) in the vast amount of data contained within network file systems is useful for both users and system administrators. In this paper we discuss the Essence resource discovery system, which exploits file semantics to index both textual and binary files. By exploiting semantics, Essence extracts keywords that summarize a file, and generates a compact yet representative index. Essence understands nested file structures (such as uuencoded, compressed, "tar" files), and recursively unravels such files to generate summaries for them. These features allow Essence to be used in a number of useful settings, such as anonymous FTP archives. We present measurements of our prototype and compare them to related projects, such as the Wide Area Information Servers (WAIS) system and the MIT Semantic File System (SFS). We demonstrate that Essence can index more data types, generate smaller indexes, and in some case...

To help users cope with information overload, Selective Dissemination of Information (SDI) will increasingly become an important tool in wide area information systems. In an SDI service, users post their long term queries, called profiles, at some SDI servers and continuously receive new, filtered documents. To scale up with the volume of information and the size of user population, we need a distributed SDI service with multiple servers. In this paper we first address the key problem of how to replicate and distribute profiles and documents among SDI servers. We draw a parallel between distributed SDI and the well-studied replica control problem, adapt quorum-based protocols for use in distributed SDI, and compare the performances of the different protocols. Next we address another important problem, that of efficient document delivery mechanisms. We present and evaluate a practical scheme, called profile grouping, which exploits the geographical locality of users to cut down network ...

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The InfoHarness ^TM system is aimed at providing integrated and rapid access to huge amounts of heterogeneous information independent of its type, representation, and location. This is achieved by extracting metadata and associating it with the original information. The metadata extraction methods ensure rapid and largely automatic creation of information repositories. A stable hierarchy of abstract classes is proposed to organize the processing and representation needs of different kinds of information. An extensible hierarchy of terminal classes simplifies support for new information types and utilization of new indexing technologies. InfoHarness repositories may be accessed through Mosaic or any other HyperText Transfer Protocol (HTTP) compliant browser.

Due to the rapid growth of the World-Wide Web, resource discovery has become an increasing problem. As an answer to the demand for information management, a third generation of World-Wide Web tools will evolve: information gathering and processing agents. This paper describes wave (Web Analysis and Visualization Environment), a 3D interface for World-Wide Web information visualization and browsing. It uses the mathematical theory of concept analysis to conceptually cluster objects. So-called "conceptual scales" for attributes, such as location, title, keywords, topic, size, or modification time, provide a formal mechanism that automatically classifies and categorizes documents, creating a conceptual information space. A visualization shell serves as an ergonomically sound user interface for exploring this information space. 1 Introduction The World-Wide Web has gained its amazing popularity through the availability of "point and shoot" browsing tools like Mosaic. They provide access ...

. In many large organizations there has been a proliferation of database systems to handle ever increasing volumes of information. In order to explore a potentially huge on-line information space, we must develop an architecture which allows for the dynamic data driven construction of inter--database node relationships in an incremental manner. In this paper we introduce the FINDIT architecture which uses information meta-types to provide a basis for such an organization and, consequently, provides a platform for interoperability. A distinction is made between the information and inter-node relationship spaces to achieve scalability. Tassili language primitives are used for the incremental building of dynamic inter--node relationships based upon usage considerations. Keywords: Multidatabases, Federated Databases, Interoperability, Heterogeneous and Autonomous Databases, Query Languages. 1. Introduction Sharing information among autonomous heterogeneous databases has been researched e...

Information overload, arising from different types of heterogeneous digital data readily accessible from millions of repositories, is a critical problem on the Global Information Infrastructure (GII). We present an information brokering approach, architecture and techniques that address issues related to information overload on the GII. The approach spans three levels: representation (structure/format/type) of digital data, information content captured in the data; and the vocabulary underlying the data. Metadata (data/information about data) is used to abstract from heterogeneous representational details and capture information content. Domain specific ontologies are used to represent and interoperate across different vocabularies used to characterize information content. The approach thus suggested induces a metadata-based architecture that enables information brokering at the different levels. The feasibility of the approach is demonstrated by using a wide variety of metadata to capture information content for textual, image and structured data. These metadata belong to a wide spectrum and may range from metadata independent of the data content to those capturing information content in a application and domain specific

Abstract: Content Delivery Networks (CDNs) have evolved to overcome the inherent limitations of the Internet in terms of user perceived Quality of Service (QoS) when accessing Web content. A CDN replicates content from the origin server to cache servers, scattered over the globe, in order to deliver content to end-users in a reliable and timely manner from nearby optimal surrogates. Content distribution on the Internet has received considerable research attention. It combines development of high-end computing technologies with highperformance networking infrastructure and distributed replica management techniques. Therefore, our aim is to categorize and analyze the existing CDNs, and to explore the uniqueness, weaknesses, opportunities, and future directions in this field. In this paper, we provide a comprehensive taxonomy with a broad coverage of CDNs in terms of organizational structure, content distribution mechanisms, request redirection techniques, and performance measurement methodologies. We study the existing CDNs in terms of their infrastructure, request-routing mechanisms, content replication techniques, load balancing, and cache management. We also provide an indepth analysis and state-of-the-art survey of CDNs. Finally, we apply the taxonomy to map various CDNs. The mapping of the taxonomy to the CDNs helps in “gap ” analysis in the content networking domain. It also provides a means to identify the present and future development in this field and validates the applicability and