Arthur M. Keller

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We consider the problem of updating databases through views composed of selections? projections. and joins of a series of Boyce-Codd Normal Form relations. This involves translating updates expressed against the view to updates expressed against the database. We; present five criteria that these translations must satisfy. For each type of view update(More)
Infomaster is an information integration system that provides integrated access to multiple distributed heterogeneous information sources on the Internet, thus giving the illusion of a centralized, homogeneous information system. We say that Infomaster creates a virtual data warehouse. The core of Infomaster is a facilitator that dynamically determines an(More)
We propose a new client-side data-caching scheme for relational databases with a central server and multiple clients. Data are loaded into each client cache based on queries executed on the central database at the server. These queries are used to form predicates that describe the cache contents. A subsequent query at the client may be satisfied in its(More)
This paper summarizes and analyses data compiled on the activities of email harvesters gathered through a 5,000+ member honey pot system that issues unique addresses based on a visitor’s IP address and specific spidering time. The project, known as Project Honey Pot, has provided data about the geographical source of harvesting and mail processing, the(More)
Thousands of single-copy internal eliminated sequences (IESs) are excised from the germ line genome of ciliates during development of the polygenomic somatic macronucleus, following sexual events. Paramecium IESs are short, noncoding elements that frequently interrupt coding sequences. No absolutely conserved sequence element, other than flanking 5'-TA-3'(More)
Update propagation and transaction atomicity are major obstacles to the development of replicated databases. Many practical applications, such as automated teller machine networks, flight reservation, and part inventory control, do not require these properties. In this paper we present an approach for incrementally updating a distributed, replicated(More)
The view-object model provides a formal basis for representing and manipulating object-based views on relational databases. In this paper, we present a scheme for handling update operations on view objects. Because a typical view object encompasses multiple relations, a view-object update request must be translated into valid operations on the underlying(More)
In this paper we consider approaches to updating databases containing null values and incomplete information. Our approach distinguishes between modeling incompletely known worlds and modeling changes in these worlds. As an alternative to the open and closed world assumptions, we propose the expanded closed world assumption. Under this assumption, we(More)
Infomaster is a virtual information system that allows users to access a variety of heterogeneous, distributed information from multiple perspectives. Infomaster accesses information stored in databases or knowledge bases using Agent Communication Language (ACL), a combination of KQML, KIF, and Ontologies. Facilitators are used decompose, route, and(More)
Recent pioneering work opened the way for cloning genes in Paramecium by functional complementation of mutants. We present here the construction and pilot utilization of a new indexed library of Paramecium macronuclear DNA. The library is made of 61,440 clones containing inserts mostly between 6 and 12 kilobases. It has already allowed the complementation(More)