Descriptive Name Services for Large Internets

This thesis addresses the challenge of locating people, resources, and other objects in the global Internet. As the Internet grows beyond a million hosts in tens of thousands of organizations, it is increasingly difficult to locate any particular object. Hierarchical name services are frustrating, because users must guess the unique names for objects or navigate the name space to find information. Descriptive (i.e. relational) name services offer the promise of simple resource location through a non-procedural query language. Users locate resources by describing resource attributes. This thesis makes the promise of descriptive name services real by providing fast query processing in large internets. The key to speed in descriptive query processing is constraining the search space using two new techniques, called an active catalog and meta-data caching. The active catalog constrains the search space for a query by returning a list of data repositories where the answer to the query is li..

Distributed Active Catalogs and Meta-Data Caching in Descriptive Name Services

Today's global internetworks challenge the ability of name services and other information services to locate data quickly. We introduce a distributed active catalog and meta-data caching for optimizing queries in this environment. Our active catalog constrains the search space for a query by returning a list of data repositories where the answer to the query is likely to be found. Meta-data caching improves performance by keeping frequently used characterizations of the search space close to the user, and eliminating active catalog communication and processing costs. When searching for query responses, our techniques contact only the small percentage of the data repositories with actual responses, resulting in search times of a few seconds. We implemented a distributed active catalog and meta-data caching in a prototype descriptive name service called "Nomenclator. " We present performance results for Nomenclator in a search space of 1000 data repositories. 1. Introduction Users canno..

An industrial case study of bypass testing on web applications

Web applications are interactive programs that are deployed on the world wide web. Their execution is usually controlled very heavily by user choices and user data. This makes them vulnerable to abnormal behavior from invalid inputs as well as security attacks. Thus, web applications invest heavily in validating user inputs according to defined constraints on the values. This work focuses on validation done on the client, which uses two types of technologies; restrictions in HTML form fields and scripts that check values. Unfortunately users have the ability to subvert or skip client-side validation. Bypass testing has been developed to test the behavior of web applications when client-side validation is skipped. This paper presents results from an industry case study of bypass testing applied to a project fro

Query-Answering Algorithms for Information Agents

We describe the architecture and queryanswering algorithms used in the Information Manifold, an implemented information gathering system that provides uniform ac- cess to structured information sources on the World-Wide Web. Our architecture provides an expressive language for describing information sources, which makes it easy to add new sources and to model the fine-grained distinctions between their contents. The queryanswering algorithm guarantees that the descriptions of the sources are exploited to access only sources that are relevant to a given query. Accessing only relevant sources is crucial to scale up such a system to large numbers of sources. In addition, our algorithm can exploit run-time information to further prune information sources and to reduce the cost of query planning