We will present some ideas about sharing a secret in a monotonic access structure. We show the relations which occur between the method of encrypting a monotonic access structure with the use of basis sets or maximal unprivileged sets, and that based on a logical formula (used by Benaloh and Leichter in [1]). We will also give some facts connected with the problem of security, including the asp...

Access control systems are among the most critical of computer security components. Faulty policies, misconfigurations, or flaws in software implementations can result in serious vulnerabilities. To formally and precisely capture the security properties that access control should adhere to, access control models are usually written, bridging the gap in abstraction between policies and mechanism...

The performance of access methods and the underlying disk system is a significant factor in determining the performance of database applications, especially with large sets of data. While modern hard disks are manufactured with multiple physical zones, where seek times and data transfer rates vary significantly across the zones, there has been little consideration of this important disk charact...

LA UKkNCE E. MILSTEI>V is aprofessor with the Department ofElecmncal and Computer Engineering at the L’niwsily of California at San D q o . ver the past several years, code division multiple access (CDMA) has been shown to be a viable alternative to both frequency division multiple access (FDMA) and time division multiple acccss (TDMA), and the use of spread spectrum techniques (upon which CDMA...

By supporting the valid and transaction time dimensions, bitemporal databases represent reality more accurately than conventional databases. In this paper, we examine the issues involved in designing efficient access methods for bitemporal databases, and propose the partial-persistence and the double-tree methodologies. The partial-persistence methodology reduces bitemporal queries to partial p...

Despite the fact that the database community has proposed a vast number of indexing methods over the years, no standard physical data model has been established like it has been achieved on the conceptual and logical level. How to optimize a given data model by using various indexing methods is still the ‚trade secret‘ of the database administrators. Only recently, some approaches have been tri...

Interest in multidimensional data has been steadily rising in the database community. Storage and subset retrieval of multi-dimensional data is necessary for scienti c, geographic, temporal and business data. Our research has concentrated on developing techniques for e cient loading, retrieval, and update of multi-dimensional data. Current commercial systems (with the exception of one) do not s...

This paper is a survey of work and issues on multidimensional search trees. We provide a classification of such methods, we describe the related algorithms, we present performance analysis efforts, and finally outline future research directions. Multi-dimensional search trees and Spatial Access Methods, in general, are designed to handle spatial objects, like points, line segments, polygons, po...

Designing and tuning access methods (AMs) has always been more of a black art than a rigorous discipline, with performance assessments being mostly reduced to presenting bottom-line runtime or I/O numbers. (This paper presents an analysis framework for AMs that gives detailed feedback about observed page access performance and the performance implications of individual aspects of an AM design.)...

Designing and tuning access methods (AMs) has always been more of a black art than a rigorous discipline, with performance assessments being mostly reduced to presenting aggregate runtime or I/O numbers. This paper presents amdb, a comprehensive graphical design tool for AMs that are constructed on top of the Generalized Search Tree abstraction. At the core of amdb lies an an analysis framework...