Showing papers on "Spatiotemporal database published in 1993"

Managing Temporal Financial Data in an Extensible Database

Abstract: 1 Introduction Complex financial products and trading applications are difficult to model and implement in conventional commercial databases due to temporal, object, rule and other data support requirements. Extensible database systems provide a better solution because of the ability to define complex data types, manipulate data of type procedure , define rules, operators and access methods to optimize these operators. The paper discusses the design issues in modeling financial trading systems in extensi-ble DBMS. The complexity of financial products is analyzed and strategies for modeling these products are pro posed. Operators relevant to financial trading are discussed alongwith access methods to optimize these operators. The paper describes an implementation of a financial trading system in POSTGRES. Since 1971, after the breakdown of the Bretton WoodswANK system of fixed exchange rates, financial markets have seen a sharp increase in the fluctuation of interest rates and exchange rates. The past 20 years have also seen rapid advances in information technology that make it possible to collect and process large amounts of data. These events, when coupled with the sophistication of financial theory, have created a marketplace of a vast array of financial products that cater to different investment needs. Financial Trading Applications, which are meant to facilitate trading in these products, have also become very complex because : There are a variety of complex financial products available and the dynamic nature of the market, coupled with a decrease in regulation, has created a situation in which new products are introduced often and old ones discontinued. Trading strategies are baaed on numerically intensive procedures and complex mathematical relationships between financial products. The decrease in the cost of telecommunications and the increased reliability of networks make profitable trading opportunities available only for short periods of time. of Energy under Contract DEACO3-76SFWOQS. Pennirrion to copy witliout fee all or part of tlir material ir granted provided tlat tAc copier are not made or distributed for direct commercial advantage, tAc VLDB copyriglt notice and tAe title of the publitaiion and iir date appear; and notice in given tAat copying ir by pemaierion of tAe Ver) Large Data Base Endowmeni. To copy oiAetwire, or to republirl, reqmiree e fee and/or rpecial permiraion from tAc Endowment. The proliferation of financial products, increase in information and rapid advances in technology keep trading houses and investment firms under constant pressure to develop new ad-hoc applications for financial trading support. These …

What's special about spatial?: database requirements for vehicle navigation in geographic space

Abstract: Geographic databases are becoming a popular subject for research projects. It is acknowledged that database requirements for such applications as Geographic Information Systems (GISs), computer cartography, remote-sensing image databases, and emergency routing/dispatching are distinct from those for traditional database applications; however, the specific database needs due to the properties of geographic data are frequently overlooked. Here, we describe a specific problem domain, a vehicle navigation system, and analyze the properties of data to be modeled appropriately and managed efficiently by database management systems. Vehicle navigation systems need continuous, fast access to very large databases. Through the combination of real-time access and geographic data, we identify particularly challenging database requirements of this application with respect to data models, query languages, and query processing.

Bibliography on spatiotemporal databases

Abstract: Spatial and temporal databases are important and well-established sub-disciplines of database research. Some 350 papers in temporal databases have appeared, authored by almost 300 researchers. The literature on spatial databases is also substantial; the bibliography of Samet's landmark book on spatial data structures lists 823 references.

Aggregation in Constraint Databases.

Abstract: We discuss the issues that arise when we add aggregation to a constraint database query language. One example of the use of ag-gregation in such a context is to compute the area of a region in a geographic database. We show how aggregation could be added to the query language, tuple calculus, and discuss the problems that arise from the interaction of aggregate operators and constraints.

Geographical object–oriented databases—a case study

Abstract: An Australian standard for Spatial Data Transfer modelled on the draft American standard is likely to be introduced in 1993. The spatial data model is not accommodated by existing DBMS such as relational systems. Using this model as an example, the suitability of object–oriented database systems for geographical databases is demonstrated. Some initial performance figures obtained with the ONTOS system on an example database are given.

Caching and database scaling in distributed shared-nothing information retrieval systems

Abstract: A common class of existing information retrieval system provides access to abstracts. For example Stanford University, through its FOLIO system, provides access to the INSPECT database of abstracts of the literature on physics, computer science, electrical engineering, etc. In this paper this database is studied by using a trace-driven simulation. We focus on physical index design, inverted index caching, and database scaling in a distributed shared-nothing system. All three issues are shown to have a strong effect on response time and throughput. Database scaling is explored in two ways. One way assumes an “optimal” configuration for a single host and then linearly scales the database by duplicating the host architecture as needed. The second way determines the optimal number of hosts given a fixed database size.

On Implementing a Language for Specifying Active Database Execution Models

Abstract: A key issue when incorporating rules into database systems concerns understrnding alternative semantics of rule application. The database progrsmming language Heraclitus[Alg,C] is an HI RMIIUS extension of C that supports the relational algebra and novel constructs related to the specification of these semantics. In particular. the language supports delta aa “first&se citizens” .theue are values corresponding to database updates, which may or may not be applied. Deltas are useful in representing the effect of rule firings, and for representing virtual dntabaae states, as they arise in the specification of several active database systems. Unlike previous work on clilTerential files and hypothetical relations, Heraclitun supports operators for combining deltas, and also alternative implementations that incorporate the impact of deltas into conventional database operators (e.g., join). The framework alAo appcsarw useful in connection with hypothetical database acrens, vcrsiou control, specifying concurrency protocols, and thr resolution of update conflicts. This paper dencribea the design and preliminary implementation of Heraclitus[Alg,C]. Two strategies for providing access to d&au have been implemented, one hash-based and the other sort-based. Initial evaluation of system performance demonstrates the feasibility of the language. *This work was supported in part by the NSF under grants IRI-9110522, IHI-910705S,INT-8817874, NYI award IRI-9258362, and tire USC FRIF under grant 22-1509-9440. tThis author’s current address: Computer Science Department, University of Colorado, Boulder, CO 80309. Yrrmirrion to copy wiihout fee all or part of thir material is granted provided that the copier are not made or distributed for direct commercial advantage, the VLllB copyright notice and the title oJ the publication and itr date appear, and notice ir given that copying ir by petmirrion OJ the Very Large Data Bare Endowmrnt. l’o copy otherwire, or to republirh, require4 a Jee and/or special permirsion from the Endowment. Proceedings of tbe 19tb VLDB Conference Dublin, Ireland 1993

Strong Integration of Spatial Domains and Operators in a relational Database System

Abstract: Managing and manipulating spatial data requires selective access to these data, performance at access level, and data protection. The need for a single spatial database system, integrating in a single model both alphanumeric and geometric data, is discussed. Such a database system, GeoSabrina, has been developed as an extension of an already existing relational database system. The system supports spatial data with corresponding spatial operators. Data manipulation is easily made through a spatial extension of SQL. Optimization techniques are used, providing for a strong integration of spatial operators based on spatial indexing and join-indices techniques. Built-in spatial functionalities may be further extended by application programmers through object oriented features.

An Active Object-Oriented Database: A Multi-Paradigm Approach to Constraint Management

Abstract: Mb describe the design and implementation of a constraint management facility for our active object-oriented database system called Jasmine/A. The facility includes integrity constraints, events/triggers, and constraint rules. The facility enables the user to handle both interobject and intraobject constraints, to define both primitive and composite events, and to populate databases with values satisfying specified constraints. We have taken a multi-paradigm approach to construint management. All the paradigms are integrated into object-oriented databases. We describe the semantics of the constraint management facility by extending the conventional terms of trrnsactions and consistency. Evaluation is done officiontly using puge buffers for constraints associated with sot-oriented access and object buffers for those associated with individual object access. Users are also able to control the constraint evaluation.

Modeling Time: Adequacy of Three Distinct Time Concepts for Temporal Databases

Abstract: In this paper we present newly elaborated time concepts for precise and lossless information preservation in temporal databases. First we introduce notions of temporal validity and interpretation-based validity, which help us correctly understand various time concepts introduced earlier for temporal databases. We, then, discuss the problem of preserving multiple past states of a temporal database and argue that three time concepts, valid time, transaction time, and event time are needed to attain the preservation. Lastly a simple and effective representation of temporal information with two-dimensional time is introduced.

Temporal database modeling: an object-oriented approach

Abstract: This work proposes a number of different approaches for incorporating temporal extensions to object-oriented databases. One important question that arises when dealing with temporal databases in the context of objec&oriented systems is whether to associate time with objects or with attributes. Results of previous work comparing tuple (ob ject) versioning and attribute versioning — such as whether to extend flat (F’NF) or nested (NF’NF) relational models — are not applicable to temporal object-oriented databases. This is because object-oriented models provide more powerful constructs than traditional modeis for structuring complex objects. Our goal in this paper is to study alternative temporal object-oriented database representations by identifying the different techniques for representing temporal databases in an object-riented framework. This is in contrast to other work that adopts a single particular approach. Our goal is to determine the particular situation for which each repr~ sentation is applicable. We define the concepts of object versioning and attribute versioning in temporal object-oriented models, and we concentrate on identifying the various representations of temporal relationships between objects. Another contribution of this paper is to analyze our different temporal representations and to determine their storage requirement. A general framework is defined in which the characteristics of various temporal models are studied. A simulation study is performed comparing storage costs of our various temporal representations, and also a temporal FNF relational representation. * Computer Science Engineering Department ,The University of Texas at Arlington, Arlington, Texas 76019, Fax: (817) 2733784, Telephone: (817) 273-3785, Email: ehnasri@cse.uta.edu. t Office Of The Vice President for Resemch & Information Technology, Rice University, P.O. Box 1892, Houston, Texas 77251, Fax: (713) 523-0259, Telephone: (713) 523-0080, Email: vram@rice .edu. This work was done while the author was *ociated with The University of Texas at Arlington. ~ Computer Science Engineering Department ,The University of Texas at Arlington, Arlington, Texas 76019, Fax: (817) 2733784, Telephone: (81 7) 2733785, Email: fernando@cse.uta.edu. Permission to copy without fee afl or pwt of this material is grantad providatf that tho copies aro not made or cfistributad for direct commercial advantaga, tha ACM cop~ight notico ●nd tha titla of the publication and ita date appeor, ●nd notice is @ven that copying ia by parmkion of tha Association for Computing Machinary. 10 copy otherwise, or to rapublish, requires a faa arrdlor specific permission. CIKM ’93-1 l/93/O. C., USA @ 1993 ACM 0-89791-626-3/93/001 1 .. ..$1.50

Strict histories in object-based database systems

Abstract: Atomicity and durability are integral properties of transactions. Atomicity states that all the operations associated with a transaction must be executed to completion, or none at all. Durability states that the effects of a committed transaction are never undone (that is, effects of a committed transaction are persistent). If a history resulting from the concurrent execution of transactions is to preserve the atomicity and durability properties, then it must be at least recoverable [BHG87] (a history is a sequence of read, write, commit, and abort operations belonging to all the transactions executed in the system). A history h is recoverable if for any two transactions Ti and Tj in h, if Tj reads the value of a data item written by Ti, then Ti commits or aborts before Tj commits. In a recoverable history, it is possible to undo the effects of aborted transactions without undoing the effects of committed transactions. However, in a recoverable hktory, undoing the effects of an aborted transaction may result in cascading aborts, which may incur a significant overhead [BHG871. To avoid thb problem, histories can be further restricted to be cascadeless. A hktory is caacadeless if for any two transactions Ti and Tj in h, if Tj reads the value of a data item written by Ti, then Ti commits or aborts before Tj reads the data item. In cascadeless Kktories, undoing the effects of an aborted transaction does not require other transactions (committed or uncommitted)

On temporal modeling in the context of object databases

Abstract: Niki Piss inou ° Cen te r For A d v a n c e d C, o m p u t e r S tudies Univers i ty of S o u t h w e s t e r n Lou i s i ana La faye t t e , Lou i s i ana p iss inou@cacs .us l .edu Kia Makki Dept . of C o m p u t e r Science Univers i ty of Nevada Las Vegas, Nevada k ia@unlv .edu Yelena Yesha C o m p u t e r Science Dept . Un ive r s i ty of M a r y l a n d B a l t i m o r e , M a r y l a n d y e y e s h a @ c s . u m b c . e d u

Functional Dependencies Generalized for Temporal Databases that Include Object-Identity

Abstract: Normalization theory for relational databases is based on the construct of functional dependency. In this paper, we extend the formalism of functional dependency for temporal databases that include object-identity. The proposed extensions are used to compare object-oriented modeling and Extended Entity-Relationship modeling in structural and temporal terms.

Object-Oriented Databases

Abstract: 1. What is Meant by Objects? 2. Constructing the Object-Oriented Environment 3. Approaches to Object-Oriented Programming 4. Objects and the Process of Prototyping 5. Why an Object Database? 6. Spatial and Temporal Semantics 7. Why Should We Care for Multimedia Databases? 8. Primitives of the Global Database 9. Beyond Relational Database Management Systems 10. DBMS for Object-Oriented Databases 11. Distributed Deductive Databases 12. Knowledgebanks and Databases 13. Intentional and Extentional Databases 14. Objects and Data Level Parallelism

CoBase: A Cooperative Query Answering Facility for Database Systems

Abstract: A new generation of database that integrates knowledge base technology with database systems is presented for providing cooperative (approximate and conceptual) query answering. Based on the database schema and application characteristics, data are organized into type abstraction hierarchies. The higher levels of the hierarchy provide a more abstract data representation than the lower levels. Generalization (moving up in the hierarchy), specialization (moving down in the hierarchy) and association (moving between hierarchies) are the three key operations in deriving cooperative query answers. A relaxation manager is included to provide control for query relaxations. An Explanation System is also included to describe the relaxation process and provide the nearness of the approximate answer. We have demonstrated the feasibility and functionality of CoBase on top of a transportation relational database. The CoBase methodology has also been adopted in the knowledge based multimedia medical distributed database project [5] at UCLA.

A Browser for a Versioned Entity-Relationship Database

Abstract: In database systems supporting versioning, there exist two information spaces, the version space and the product space. The version space contains a point for each possible configuration of the product, and the product space consists of the individual components comprising the product. While conventional models represent these spaces in an intertwined structure, the change-oriented versioning model allows them to be treated quite separately.

EMBL–Search: a CD–ROM based database query system

Abstract: This paper describes a system of generally applicable index files provided on the EMBL sequence databases CD-ROM to facilitate the development of front-end software to the sequence databases available on this CD-ROM. The index files are used by a new versatile and user-friendly database retrieval program for the Apple Macintosh, EMBL-Search, which allows the easy construction of complex database queries. EMBL-Search utilizes cross-reference information contained in the databases to support navigation between different information resources. The ability to run EMBL-Search on a local computer network accessing a shared database CD-ROM makes its use particularly cost effective.

Performance of Catalog Management Schemes for Running Access Modules in a Locally Distributed Database System

Abstract: Catalog management schemes affect many aspects of distributed database systems such as site autonomy, query optimization, view management, authorization mechanism, and data distribution transparency. However, the performance comparison of various catalog management schemes has received relatively little attention. Embedded read queries to the catalogs in a form of data manipulation statements are assumed to be compiled into an access module, since the module is executed repeatedly with different parameters. Update queries to the catalogs are assumed to be interpreted due to their interactive nature. The performance of the catalog management schemes measured in terms of running access modules is investigated using simulation approach in a locally distributed database system. The three alternatives studied include the centralized catalogs, the fully replicated catalogs, and the partitioned catalogs.

An incremental algorithm for building temporal quadtrees

Abstract: Research involving applications such as geographic information systems, digital cartography, machine-drawing understanding systems, and medical imaging systems has recently focused considerable attention on spatial databases that support temporal reasoning. To develop such applications, several spatiotemporal data models have been proposed. In this work, an incremental algorithm is presented for building temporal quadtrees from a sequence of time-stamped grids. The temporal quadtree data model is particularly well-suited for applications involving highly homogeneous spatiotemporal data. Analysis of the algorithm reveals that an upper bound on its execution time is proportional to the product of the number of time-stamped grids involved and the number of cells in each grid.