Image databases: Problems and perspectives

With the increasing number of computer graphics, image processing, and pattern recognition applications, economical storage, efficient representation and manipulation, and powerful and flexible query languages for retrieval of image data are of paramount importance. These and related issues pertinent to image data bases are examined

Web-based public participation GIS application : a case study on flood emergency management

Scientific summary The increasing prevalence of natural disasters is driving people to pay more and more attention to emergency management. Progress in catastrophe analysis capabilities based on Geographical Information System (GIS) may allow the needs of public participation to be considered. Synchronous data sharing between citizens and emergency workers could effectively promote the process of decision making. This thesis introduces an interactive web-based application which mainly deals with flood risk management in Kamloops in Canada. The application is built for citizens and emergency workers using three layers: (1) the client side is developed in HTML and JavaScript; (2) the web server layer, which connects the users and the database, is implemented in PHP; and (3) the database contains PostgreSQL, GeoServer and OSM. Except the city map, PostgreSQL stores the spatial information with the support of OpenGIS. Generally, the application meets the initial objectives. Citizens can access present shelter information and register their own requirements for shelter, while emergency workers have the power to manage all the shelters and warehouses based on the available flood information and figure out the supply allocation solution based on the response from the public. On the other hand, the application also provides useful routing functions for both citizens and emergency workers, such as searching the available shortest path to a shelter, and computing the optimized allocation routes between all the shelters and warehouses. This practical study proved that Public Participation GIS (PPGIS), combined with IT knowledge, can provide very useful tools for decision making when facing a flood risk.Popularized summary Nowadays, the growing prevalence of natural disasters is driving people to pay more and more attention to emergency management. Progress in catastrophe analysis capabilities based on Geographical Information System (GIS) may allow the needs of public participation to be considered. Synchronous data sharing between citizens and emergency workers could effectively promote the process of decision making. This thesis introduces an interactive web-based application which mainly deals with flood risk management in Kamloops in Canada. The application contains various data sources and adopts spatial database. Citizens can access present shelter information and register their own requirements for shelter, while emergency workers have the power to manage all the shelters and warehouses based on the available flood information and figure out the supply allocation solution based on the response from the public. On the other hand, the application also provides useful routing functions for both citizens and emergency workers, such as searching the available shortest path to a shelter, and computing the optimized allocation routes between all the shelters and warehouses. This practical study proved that Public Participation GIS (PPGIS), combined with IT knowledge, can provide very useful tools for decision making when facing a flood risk

Design And Implementation Of Wireles Sensor Networks For Parking Management System

The technology of wirelessly networked micro sensors promises to revolutionize the way we interact with the physical environment. A new approach to solve parking-related issues of vehicles in parking lots using wireless sensor networks is presented. This approach enables the implementation of the Parking Management System (PMS®) in public parking lots found in Airports, Commercial Buildings, Universities, etc. The design architecture of the sensor nodes is discussed here. An overall view of the sensor network, which covers the whole of the parking lot, is also summarized. Detailed description of the software architecture that supports the hardware is provided. A sample experiment for detecting the movement of vehicles by placing the sensor nodes allowing vehicles to pass over it is performed. The readings are sent to a local database server, which gives an indication of the actual number of vehicles parked in the building at any time. This application-oriented project also identifies important areas of further work in power management, communication, collaborative signal processing and parking management

Efficient geographic information systems: Data structures, Boolean operations and concurrency control

Geographic Information Systems (GIS) are crucial to the ability of govern mental agencies and business to record, manage and analyze geographic data efficiently. They provide methods of analysis and simulation on geographic data that were previously infeasible using traditional hardcopy maps. Creation of realistic 3-D sceneries by overlaying satellite imagery over digital elevation models (DEM) was not possible using paper maps. Determination of suitable areas for construction that would have the fewest environmental impacts once required manual tracing of different map sets on mylar sheets; now it can be done in real time by GIS. Geographic information processing has significant space and time require ments. This thesis concentrates on techniques which can make existing GIS more efficient by considering these issues: Data Structure, Boolean Operations on Geographic Data, Concurrency Control. Geographic data span multiple dimensions and consist of geometric shapes such as points, lines, and areas, which cannot be efficiently handled using a traditional one-dimensional data structure. We therefore first survey spatial data structures for geographic data and then show how a spatial data structure called an R-tree can be used to augment the performance of many existing GIS. Boolean operations on geographic data are fundamental to the spatial anal ysis common in geographic data processing. They allow the user to analyze geographic data by using operators such as AND, OR, NOT on geographic ob jects. An example of a boolean operation query would be, Find all regions that have low elevation AND soil type clay. Boolean operations require signif icant time to process. We present a generalized solution that could significantly improve the time performance of evaluating complex boolean operation queries. Concurrency control on spatial data structures for geographic data processing is becoming more critical as the size and resolution of geographic databases increase. We present algorithms to enable concurrent access to R-tree spatial data structures so that efficient sharing of geographic data can occur in a multi user GIS environment

Index of Dimensional Projection : an Index Supporting Search for Spatial Objects by Region�

In image databases and other spatial data retrieval systems, the techniques for storing and indexing data objects require different kinds of search and query from those in traditional databases and data retrieval systems. In order to handle spatial data more efficiently, a new index structure supporting search for spatial objects by region, the Index by Dimensional Projection is proposed in this thesis. By this method, the number of pages accessed for searching a point region has a logarithmic relationship with the number of objects in data space and the number of comparisons required for searching an entry within a disk page has logarithmic relationship with the number of entries in the disk page.Computer Scienc

A Program Visualization System That Supports the Program Understanding Process.

The goal of this research is to provide a graphical system that supports the program understanding process by representing the program\u27s control flow, the code and the identifiers local to a specific point within the program. By having more information local to the point of interest, the programmer can maintain continuity in developing program understanding. The programmer can see loops, procedure calls, and other structures with respect to their execution order and can view them in the environment or the context in which they will execute. The Peec system supplies a graphical representation of the program\u27s control flow in which the control structures are represented as tiers. The tiers are arranged in a three-dimensional space representing the program\u27s operational flow. The body of the procedure or function is nested within the reference tier so that the programmer views the routine local to its reference point. Also, a list of live identifiers is displayable for the current tier element. The advantage is that the routine\u27s text and the identifier list are local to the area of study and the programmer does not have to look elsewhere for the program text and the identifier definition. The programmer can maintain a continuity in developing program understanding using information local to the point of interest. The Peec system consists of the Peec compiler which transforms a Pascal program into tier and identifier information, and the Peec environment for modeling the program\u27s operational flow image. The Peec environment provides the programmer many interactive capabilities. These capabilities consist of browsing the flow model, displaying text, displaying identifiers and transforming the three-dimensional flow model into appropriate views. These features are aimed at assisting the programmer in the processing of developing program understanding

The Ubiquitous B-tree: Volume II

Major developments relating to the B-tree from early 1979 through the fall of 1986 are presented. This updates the well-known article, The Ubiquitous B-Tree by Douglas Comer (Computing Surveys, June 1979). After a basic overview of B and B+ trees, recent research is cited as well as descriptions of nine B-tree variants developed since Comer\u27s article. The advantages and disadvantages of each variant over the basic B-tree are emphasized. Also included are a discussion of concurrency control issues in B-trees and a speculation on the future of B-trees