22 research outputs found

    A SIMPLE, GENERAL STRUCTURE FOR TEMPORAL DOMAINS

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    Much recent research has focused on .the need for, and definitions of, historical (or temporal) database and information systems to serve expanding information needs in a variety of applications. Almost all of this research has assumed that the domain of time itself was well-understood, and some representation for it simply needed to be included in the model to provide the needed temporal dimension. In this paper we present a simple, set-theoretic structure for a time domain which is independent of any particular calendric system. We concentrate on the general structure and operations necessary to support the needs arising in modelling time in information systems.Information Systems Working Papers Serie

    Operations on (ordered) interval sets

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    Intervals play an important role in various kinds of database-applications in practice, for example in historical, spatial, and temporal databases. As a consequence, there is a practical need for a clear and proper treatment of various useful operations on intervals and interval sets in a database context. However, the semantics of some important operations on interval sets are not always treated or not treated very clearly in the literature; e.g., often they are defined in an algorithmic rather than a declarative manner. Moreover, implementation proposals are often not as straightforward as they could be. This paper presents a declarative treatment of various operations on interval sets, also introducing some new notions (such as ordered interval sets, their visible points, and their surface). Then the paper formally ?links? such (mathematical) intervals to their database representations. Finally the paper provides straightforward translations from these formal database representations to standard SQL, without the need for SQL extensions.

    TEMPOS: A Platform for Developing Temporal Applications on Top of Object DBMS

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    This paper presents TEMPOS: a set of models and languages supporting the manipulation of temporal data on top of object DBMS. The proposed models exploit object-oriented technology to meet some important, yet traditionally neglected design criteria related to legacy code migration and representation independence. Two complementary ways for accessing temporal data are offered: a query language and a visual browser. The query language, namely TempOQL, is an extension of OQL supporting the manipulation of histories regardless of their representations, through fully composable functional operators. The visual browser offers operators that facilitate several time-related interactive navigation tasks, such as studying a snapshot of a collection of objects at a given instant, or detecting and examining changes within temporal attributes and relationships. TEMPOS models and languages have been formalized both at the syntactical and the semantical level and have been implemented on top of an object DBMS. The suitability of the proposals with regard to applications' requirements has been validated through concrete case studies

    Implementação de aspectos temporais em SGBDs livres

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    O trabalho apresenta um estudo sobre a viabilidade de implementação de aspectos temporais, nos SGBD open-source PostgreSQL, Ingres, Firebird e MySql, tratando três modalidades diferentes: (1) tabela instantânea para BD de tempo de transação, (2) visão para BD de tempo de transação, e (3) tempo de validade. Foram consideradas as funcionalidades oferecidas por estes SGBD e o grau de transparência no tratamento dos dados para dois perfis de usuários: (a) os interessados nos aspectos temporais dos dados e (b) os que tratam os dados como em bancos de dados instantâneos. Como contribuição, é mostrado que, em MySql, muito pouco pode ser implementado, por enquanto, e em PostgreSQL podem ser implementadas características temporais, com total transparência na atualização dos aspectos temporais dos dados. Também é apresentada neste artigo uma ferramenta de apoio ao desenvolvimento de bancos de dados temporais em SGBDs livresII Workshop de Ingeniería de Software y Bases de Datos (WISBD)Red de Universidades con Carreras en Informática (RedUNCI

    Implementação de aspectos temporais em SGBDs livres

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    O trabalho apresenta um estudo sobre a viabilidade de implementação de aspectos temporais, nos SGBD open-source PostgreSQL, Ingres, Firebird e MySql, tratando três modalidades diferentes: (1) tabela instantânea para BD de tempo de transação, (2) visão para BD de tempo de transação, e (3) tempo de validade. Foram consideradas as funcionalidades oferecidas por estes SGBD e o grau de transparência no tratamento dos dados para dois perfis de usuários: (a) os interessados nos aspectos temporais dos dados e (b) os que tratam os dados como em bancos de dados instantâneos. Como contribuição, é mostrado que, em MySql, muito pouco pode ser implementado, por enquanto, e em PostgreSQL podem ser implementadas características temporais, com total transparência na atualização dos aspectos temporais dos dados. Também é apresentada neste artigo uma ferramenta de apoio ao desenvolvimento de bancos de dados temporais em SGBDs livresII Workshop de Ingeniería de Software y Bases de Datos (WISBD)Red de Universidades con Carreras en Informática (RedUNCI

    Query processing in temporal object-oriented databases

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    This PhD thesis is concerned with historical data management in the context of objectoriented databases. An extensible approach has been explored to processing temporal object queries within a uniform query framework. By the uniform framework, we mean temporal queries can be processed within the existing object-oriented framework that is extended from relational framework, by extending the existing query processing techniques and strategies developed for OODBs and RDBs. The unified model of OODBs and RDBs in UmSQL/X has been adopted as a basis for this purpose. A temporal object data model is thereby defined by incorporating a time dimension into this unified model of OODBs and RDBs to form temporal relational-like cubes but with the addition of aggregation and inheritance hierarchies. A query algebra, that accesses objects through these associations of aggregation, inheritance and timereference, is then defined as a general query model /language. Due to the extensive features of our data model and reducibility of the algebra, a layered structure of query processor is presented that provides a uniforrn framework for processing temporal object queries. Within the uniform framework, query transformation is carried out based on a set of transformation rules identified that includes the known relational and object rules plus those pertaining to the time dimension. To evaluate a temporal query involving a path with timereference, a strategy of decomposition is proposed. That is, evaluation of an enhanced path, which is defined to extend a path with time-reference, is decomposed by initially dividing the path into two sub-paths: one containing the time-stamped class that can be optimized by making use of the ordering information of temporal data and another an ordinary sub-path (without time-stamped classes) which can be further decomposed and evaluated using different algorithms. The intermediate results of traversing the two sub-paths are then joined together to create the query output. Algorithms for processing the decomposed query components, i. e., time-related operation algorithms, four join algorithms (nested-loop forward join, sort-merge forward join, nested-loop reverse join and sort-merge reverse join) and their modifications, have been presented with cost analysis and implemented with stream processing techniques using C++. Simulation results are also provided. Both cost analysis and simulation show the effects of time on the query processing algorithms: the join time cost is linearly increased with the expansion in the number of time-epochs (time-dimension in the case of a regular TS). It is also shown that using heuristics that make use of time information can lead to a significant time cost saving. Query processing with incomplete temporal data has also been discussed

    Developments in spatio-temporal query languages

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    Human Resource Development climate and organizational citizenship behavior: a comparative study of Banking industry.

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    The aim of the present study was to inspect and explore the relationship between Human Resource Development Climate (HRD C) and Organizational Citizenship Behavior (OCB). In this study, Human Resource Development Climate (HRD C) was treated as an independent variable and Organizational Citizenship Behavior (OCB) as a dependent variable. The relationship between the independent and dependent variable was explored using Pearson’s coefficient of correlation and simple linear regression analysis. Demographic variables undertaken in this study includes; Nature of Organization, name of the organization, gender, age, tenure, and length of the service. These demographic variables have also been explored through inferential analysis using t-test, and One way ANOVA. Based on the literature support, five dimensional model conceptually proposed by organ in year 1988 and empirically validated by Podsakoff et al. in year 1990 has been used in the present study to measure Organizational Citizenship Behavior (OCB) among the employees of sample organizations. This five dimensional model of OCB includes sub-variables namely, Altruism, Conscientiousness, courtesy, civic-virtue and Sportsmanship. Whereas, a scale developed by the pioneer of HRD Climate concept Rao and Abraham (1990), is the sole measure available in the literature to measure HRD climate. It has three elements namely; General Climate, OCTAPACE Culture, and HRD Mechanisms. The present study has been conducted in the banking industry, with the two banks from private sector {namely, Jammu and Kashmir bank (JKB) and Housing development and financial corporation (HDFC)} and two banks from public sector {State bank of India (SBI) and Punjab national bank (PNB)}. The present study is based on the responses collected from 316 Branch Heads, who have been selected as a choice of source with the aim to avoid the common method variance based on the recommendations available in the literature.Digital copy of Ph.D thesis.University of Kashmir
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