Showing papers presented at "International ACM SIGIR Conference on Research and Development in Information Retrieval in 1975"

On the encipherment of search trees and random access files

Abstract: The securing of information in indexed, random access files by means of privacy transformations must be considered as a problem distinct from that for sequential files. Not only must processing overhead due to encrypting be considered, but also must threats to encipherment arising from updating and the file structure itself be countered. A general encipherment scheme is proposed for files maintained in a paged structure on secondary storage. This is then applied to the encipherment of indexes organized as B-trees, a particular type of multiway search tree. Threats to the encipherment of B-trees, especially relating to updating, are examined, and counter-measures proposed for each. In addition, the effect of encipherment on file access and update, on paging mechanisms, and on files related to the enciphered index are discussed. Many of the concepts presented here may be readily transferred to other forms of multiway index trees and to binary search trees.

Optimal allocation of resources in distributed information networks

Abstract: The problems of file allocation and capacity assignment in a fixed topology distributed computer network are examined. These two aspects of the design are tightly coupled through an average message delay constraint. The objective is to allocate copies of information files to network nodes and capacities to network links so that a minimum cost is achieved subject to network delay and file availability constraints. A model for solving the problem is formulated and the resulting optimization problem is shown to fall into a class of non-linear integer programming problems. Deterministic techniques for solving this class of problems are computationally cumbersome even for small sized problems. A new heuristic algorithm is developed, based on a decomposition technique which greatly reduces the computational complexity of the problem. Numerical results for a variety of network configurations indicate that the heuristic algorithm, while not theoretically convergent, yields practicable low cost solutions with substantial savings in computer processing time and storage requirements. Moreover, it is shown that this algorithm is capable of solving realistic network problems whose solution using deterministic techniques is computationally intractable.

The design of a rotating associative array memory for a relational data base management application

Abstract: There are significant advantages to tailoring hardware storage devices to support high level data models in very large data bases. A storage device that can assume some of the data selection functions traditionally performed by the CPU can substantially reduce the amount of data to be transferred to the CPU. This reduction together with increased concurrency of CPU and device operation result in increased data rates and lower response times. By designing the device to support one specific data model, greater efficiency can be achieved than in devices designed to be a compromise in their support of several different models. The number and complexity of the functions performed by the device can be drastically reduced, along with its development and production costs. In this paper we describe the design and usage of an associative array memory using a rotating storage device which is tailored to support the relational model of E.F. Codd.

On non-numeric architecture

Abstract: In this informal paper, we present what we believe is one of the major problems in computer science of the 70's and several approaches to the solution of this problem that are being studied by our group and by others. (A formal paper that includes a detailed bibliography on this topic is in preparation. Therefore, we are writing this paper in an informal style without references). A very large part of the computational load throughout the world is essentially business computation. Perhaps it is the majority of computation. Business computation is heavily oriented to data base management and information retrieval. We will refer to this type of computation as non-numeric processing. The main primitive operation here is the search. However, we are using standard von Neumann computers whose main primitive operation is addition. What is good for numeric problems like inverting large matrices is not necessarily good for non-numeric problems like searching large data bases. The hardware limitations of conventional von Neumann computers tend to straightjacket our approach to non-numeric processing.

Restructuring for large data bases: three levels of abstraction

Abstract: The development of a powerful restructuring function involves two important components - the unambiguous specification of the restructuring operations and the realization of these operations in a software system. We direct our efforts to the first component in the belief that a precise specification will provide a firm foundation for restructuring algorithms and implementations. This paper defines completely the semantics of the restructuring of tree structured data bases.The delineation of the restructuring function is accomplished by formulating three different levels of abstraction, with each level of abstraction representing successively more detailed semantics of the function.At the first level of abstraction, the schema modification, three types are identified: naming, combining and relating, and are further divided into eight schema operations. The second level of abstraction, the instance operations, constitutes the transformations on the data instances. They are divided into group operations such as replication, factoring, union and group relation operations such as collapsing, refinement, fusion etc. The final level, the item values operations, includes the actual item operations such as copy value, delete value, or create a null value.

On the language of information science

Abstract: 1. Lavoisier and The Nomenclature of Chemistry. As a science matures, the language used by its practitioners evolves. Hogben (1) describes the evolution of the language of several sciences. Of particular interest is his description of the evolution of the language of chemistry. The clarity of thinking in chemistry, and the progress in the field took a sharp upturn after Lavoisier introduced revolutionary changes in the system of chemical nomenclature. Before Lavoisier, substances were generally known by names that might be called recipes or histories; somebody's notion or recollection of how they first encountered the substance. Methane was known as marsh gas, because it was first found bubbling up through the mud of marshes, as a result of the decay of organic materials under the mud. Hydrochloric acid was known as muriatic acid, from muria, the Latin name for brine, a common source of hydrochloric acid. Muria, in turn, comes from mare, Latin for sea. Chlorine was known to sixteenth century chemists and alchemists as dephlogisticated muriatic acid. The original process by which chlorine was manufactured, and still a common process, is by oxidation of the hydrogen in hydrochloric acid. Since oxidation was not yet understood at that time, it was called dephlogistication -- removal of the phlogiston. Lavoisier's new nomenclature describes substances not by their surmised origin, but by their present content, structure and condition.