P. Bruce Berra

Index structures for structured documents

Much research has been carried out in order to manage structured documents such as SGML documents and to provide powerful query facilities which exploit document structures as well as document contents. In order to perform structure queries efficiently in a structured document management system, an index structure which supports fast document element access must be provided. However, there has been little research on the index structures for structured documents. In this paper, we propose various kinds of new inverted indexing schemes and signature file schemes for efficient structure query processing. We evaluate the storage requirements and disk access time of our schemes and present the analytical and experimental results.

Minimum cost selection of secondary indexes for formatted files

Secondary indexes are often used in database management systems for secondary key retrieval. Although their use can improve retrieval time significantly, the cost of index maintenance and storage increases the overhead of the file processing application. The optimal set of indexed secondary keys for a particular application depends on a number of application dependent factors. In this paper a cost function is developed for the evaluation of candidate indexing choices and applied to the optimization of index selection. Factors accounted for include file size, the relative rates of retrieval and maintenance and the distribution of retrieval and maintenance over the candidate keys, index structure, and system charging rates. Among the results demonstrated are the increased effectiveness of secondary indexes for large files, the effect of the relative rates of retrieval and maintenance, the greater cost of allowing for arbitrarily formulated queries, and the impact on cost of the use of different index structures.

A data management system utilizing an associative memory

There are a wide variety of data management systems in existence. These systems vary from those that are fairly general to those that are very specific in their performance characteristics. The former systems tend to have a longer life cycle, while sacrificing some efficiency, whereas the latter are more efficient but tend to become obsolete when requirements are modified.

Automated planning and optimization of machining processes: A systems approach

Abstract A system is presented that combines the automated planning and optimization functions in machining processes. The planning function is performed by a systematic analysis of the stated requirements of the finished part in the light of information on available machining facilities and raw materials. The optimization phase utilizes a mathematical programming model to take into account various costs and constraints under alternative machining conditions. A gradient or “hill-climbing” algorithm is shown to be a convenient optimization technique for this class of problems. Implementation of the system is illustrated in some detail for the case of the face milling process.

Some problems in associative processor applications to data base management

Associative memories and processors have been discussed in the literature for the past 15 years and a small number of hardware devices have actually been built. The usefulness of these devices can only be proven through actual applications. A number of these applications have been considered and include air traffic control, computer graphics, information retrieval, numerical analysis, networks and among others, data base management.

Associative techniques in the solution of data management problems

This paper is concerned with the development of data management systems from an associative point of view. The design utilizes relational set theory applied to information systems. The basic notion involves the mathematical transformation of hierarchical structures of n-ary relations into associative normal form (ANF). This transformation preserves the information content while at the same time allowing the information to be manipulated by an associative memory in a more efficient manner than is possible on a random access memory. Among the advantages that can be realized from this system are the capability of handling many and varied data structures; substantially fewer pointers and directories; a reduction in storage space requirements; and a substantial decrease in query and update time.

Management of Multi-structured Hypermedia Documents: A Data Model, Query Language, and Indexing Scheme

Structured documents have gained popularity with the advent of documentstructure markupstandards such as SGML, ODA, HyTime, and HTML.Document management systems can provide powerful facilities by maintaining thestructure information of documents.Since the hypermediadocument is also a kind of structured document, wecan apply the results of many studies, whichhave been performed in storing, retrieving, and managing structured documents,to the hypermedia document management.However, more factors should be considered in handling hypermedia documentsbecause they contain multimedia data and also have multiple complex structuressuch as hyperlink networks and spatial/temporal layout structures as well aslogical structures.In this paper, we propose an object-oriented model for multi-structuredhypermediadocuments and multimedia data, and a query language for retrievinghypermedia document elements based on the content and multiple complexstructures.By using unique element identifiers and an indexing scheme whichexploits multiple structures,we can process queries efficiently with minimal storage overheadfor maintaining structure information.

An evaluation of design trade-offs in a high-performance, media-on-demand server

Abstract.We present a high-performance solution to the I/O retrieval problem in a distributed multimedia system. Parallelism of data retrieval is achieved by striping the data across multiple disks. We identify the components that contribute to media data-retrieval delay. The variable delays among these have a great bearing on the server throughput under varying load conditions. We present a buffering scheme to minimize these variations. We have implemented our model on the Intel Paragon parallel computer. The results of component-wise instrumentation of the server operation are presented and analyzed. Experimental results that demonstrate the efficacy of the buffering scheme are presented. Based on our experiments, a dynamic admission-control policy that takes server workloads into account is proposed.

Associative processing of line drawings

The marriage of computer graphics and an associative memory is a natural union. This is evidenced by the widespread use of software simulations of associative memories in todays most flexible graphical systems. The content-addressability of a hardware associative memory makes conventional addressing schemes superfluous and eliminates the need for pointers required to link related data, vastly reducing system overhead. The parallel retrieval and update functions possible with a hardware associative memory remove any need for multiple storage which is so prevalent in current systems and simultaneously increases processing speed. The capability of implicitly storing relations between data further decreases the storage requirements, while increasing flexibility.

A Comparison of Concatenated and Superimposed Code Word Surrogate Files for Very Large Data/Knowledge Bases

Surrogate files are very useful as an index for very large knowledge bases to support multiple logic programming inference mechanisms because of their small size and simple maintenance requirement. In this paper, we analyse the superimposed code word (SCW) and concatenated code word (CCW) surrogate file techniques in terms of storage space and time to answer queries in various cases. One of the most important results of our analysis is that the size and the query response time of the CCW is smaller than those of the SCW when the average number of arguments specified in a query is small. It is also shown that most of the query response time is used for the surrogate file processing when the extensional database is very large. Therefore, if we use a special architecture to speed up the surrogate file processing, the total query response time can be reduced considerably.