Database Systems - Present and Future

The database systems have nowadays an increasingly important role in the knowledge-based society, in which computers have penetrated all fields of activity and the Internet tends to develop worldwide. In the current informatics context, the development of the applications with databases is the work of the specialists. Using databases, reach a database from various applications, and also some of related concepts, have become accessible to all categories of IT users. This paper aims to summarize the curricular area regarding the fundamental database systems issues, which are necessary in order to train specialists in economic informatics higher education. The database systems integrate and interfere with several informatics technologies and therefore are more difficult to understand and use. Thus, students should know already a set of minimum, mandatory concepts and their practical implementation: computer systems, programming techniques, programming languages, data structures. The article also presents the actual trends in the evolution of the database systems, in the context of economic informatics.database systems - DBS, database management systems – DBMS, database – DB, programming languages, data models, database design, relational database, object-oriented systems, distributed systems, advanced database systems

Designing data warehouses for geographic OLAP querying by using MDA

Data aggregation in Geographic Information Systems (GIS) is a desirable feature, spatial data are integrated in OLAP engines for this purpose. However, the development and operation of those systems is still a complex task due to methodologies followed. There are some ad hoc solutions that deal only with isolated aspects and do not provide developer and analyst with an intuitive, integrated and standard framework for designing all relevant parts. To overcome these problems, we have defined a model driven approach to accomplish Geographic Data Warehouse (GDW) development. Then, we have defined a data model required to implement and query spatial data. Its modeling is defined and implemented by using an extension of UML metamodel and it is also formalized by using OCL language. In addition, the proposal has been verified against a example scenario with sample data sets. For this purpose, we have accomplished a developing tool based on Eclipse platform and MDA standard. The great advantage of this solution is that developers can directly include spatial data at conceptual level, while decision makers can also conceptually make geographic queries without being aware of logical details.This work has been partially supported by the ESPIA project (TIN2007-67078) from the Spanish Ministry of Education and Science and by the QUASIMODO project (PAC08-0157-0668) from the Castilla-La Mancha Ministry of Education and Science (Spain). Octavio Glorio is funded by the University of Alicante under the 11th Latin American grant program

Using Ontologies for the Design of Data Warehouses

Obtaining an implementation of a data warehouse is a complex task that forces designers to acquire wide knowledge of the domain, thus requiring a high level of expertise and becoming it a prone-to-fail task. Based on our experience, we have detected a set of situations we have faced up with in real-world projects in which we believe that the use of ontologies will improve several aspects of the design of data warehouses. The aim of this article is to describe several shortcomings of current data warehouse design approaches and discuss the benefit of using ontologies to overcome them. This work is a starting point for discussing the convenience of using ontologies in data warehouse design.Comment: 15 pages, 2 figure

Users Integrity Constraints in SOLAP Systems. Application in Agroforestry

SpatialData Warehouse and Spatial On-Line Analytical Processing are decision support technologies which offer the spatial and multidimensional analysis of data stored in multidimensional structure. They are aimed also at supporting geographic knowledge discovery to help decision-maker in his job related to make the appropriate decision . However, if we don’t consider data quality in the spatial hypercubes and how it is explored, it may provide unreliable results. In this paper, we propose a system for the implementation of user integrity constraints in SOLAP namely “UIC-SOLAP”. It corresponds to a methodology for guaranteeing results quality in an analytical process effectuated by different users exploiting several facts tables within the same hypercube. We integrate users Integrity Constraints (IC) by specifying visualization ICs according to their preferences and we define inter-facts ICs in this case. In order to validate our proposition, we propose the multidimensional modeling by UML profile to support constellation schema of a hypercube with several fact tables related to subjects of analysis in forestry management. Then, we propose implementation of some ICs related to users of such a system

Development and implementation of air quality data mart for Ontario, Canada : a case study of air quality in Ontario using OLAP tool

This thesis describes the development and implementation of Air Quality Data Mart for Ontario Canada using Online Analytical Processing (OLAP) tool. It is followed by a case study which presents comparisons of air quality between the urban and rural areas, peak and non-peak hours, working days and weekends for various cities in Ontario. The purpose of this study is to develop a user friendly tool for historical air quality data and evaluate the functionality of the tool by extracting the data across several dimensions. The data for air quality is available on the Ontario Ministry of Environment website for 43 monitoring stations across Ontario. This data is in the form of static Hyper Text Markup Language (HTML) pages which cannot be used for analytical purposes. Air quality data mart was developed using open source OLAP. The database was designed using multidimensional modeling approach. OLAP server “Mondrian” was used as the presentation server whereas “Openi” client was used as an end user tool for this study. The different functions available in this data mart are: rollup, drill down and slice and dice the data across several dimensions such as time, location and pollutant. The most important conclusion of this thesis is the successful implementation of an air quality data mart with the possibility to extract accurate historical air quality data. The data in the form of a data mart provides numerous advantages, where it can be analyzed according to the required analytical perspective for a given city/cities. The only drawback of having data in the form of a data mart is that, if the data is drilled down to the finest precision i.e. to the hour (depending on the number of dimensions selected) the resulting chart will be very crowded but the generated report will present a complete overview of the analysis.Popular summary: Air quality data mart built in this study consists of historical air pollutant data for cities across Ontario. This data is available at the Ontario ministry of environment website from 2000-2007 for most of the cities. There is missing data for some of the cities and some pollutants as well. It is because the monitoring of those specific pollutants did not commence in or before 2000. This data mart facilitates the user to extract historical data. The user does not need to know query language skills. With user friendly interface data analysis can be performed using drag and drop feature. The statistical functions implemented in this data mart are AVG, MIN and MAX. The database is designed in a form where it is possible to extract data for a specific time period. This data can be further filtered based on location and a given pollutant. The query output is in the form of a chart and a table. It is also possible to save the analysis which can be accessed again in future for referential purposes. The air quality in Ontario was compared using parameters like weekday – weekend effect, peak hour – off peak hour, urban and rural areas etc. Most of these parameters were used for the cities of Toronto and Ottawa. The results generated by the data mart showed that the pollutant concentration levels in both cities surpassed the recommended guidelines, but there were less exceedance days monitored in Ottawa compared to Toronto. This data mart lacks the component of visual maps. It would be interesting if this data mart had a choropleth map associated with the pollutant measurements. This would enable the user to visually comprehend the air quality data. However, if there are limitations in air quality data mart for Ontario, Canada at this point it is an indicator that spatial maps with spatial statistics can be implemented in future

A Backend Framework for the Efficient Management of Power System Measurements

Increased adoption and deployment of phasor measurement units (PMU) has provided valuable fine-grained data over the grid. Analysis over these data can provide insight into the health of the grid, thereby improving control over operations. Realizing this data-driven control, however, requires validating, processing and storing massive amounts of PMU data. This paper describes a PMU data management system that supports input from multiple PMU data streams, features an event-detection algorithm, and provides an efficient method for retrieving archival data. The event-detection algorithm rapidly correlates multiple PMU data streams, providing details on events occurring within the power system. The event-detection algorithm feeds into a visualization component, allowing operators to recognize events as they occur. The indexing and data retrieval mechanism facilitates fast access to archived PMU data. Using this method, we achieved over 30x speedup for queries with high selectivity. With the development of these two components, we have developed a system that allows efficient analysis of multiple time-aligned PMU data streams.Comment: Published in Electric Power Systems Research (2016), not available ye