Clustering Spatial Data for Join Operations Using Match-based Partition

The spatial join is an operation that combines two sets of spatial data by their spatial relationships. The cost of spatial join could be very high due to the large sizes of spatial objects and the computation-intensive spatial operations. In spatial join processing, a common method to minimize the I/O cost is to partition the spatial objects into clusters and then schedule the processing of the clusters such that the number of times the same objects to be fetched into memory can be minimized. In this paper, we propose a match-based approach to partition a large spatial data set into clusters, which is computed based on the maximal match on the spatial join graph. Simulations have been conducted and the results have shown that, when comparing to existing approaches, our new method can significantly reduce the number of clusters produced in spatial join processin

Human Dimensions Research for Informed Decisions About Aquatic Restoration In New Hampshire: Environmental Justice in Implementation of Compensatory Mitigation

New Hampshire’s aquatic resources provide many important ecosystem services and values, such as recreation, wildlife habitat, flood storage, nutrient reduction, community identity and aesthetic enjoyment. However, the many competing interests that seek to benefit from New Hampshire’s aquatic resources present challenges for efforts to steward public aquatic resources in the public interest. This thesis presents findings about the environmental justice outcomes of New Hampshire’s compensatory mitigation program, the Aquatic Resource Mitigation (ARM) fund, to inform aquatic restoration policy. Previous studies have found evidence that aquatic restoration programs can lead to systemic resource relocation and patterns of inequality in outcomes. Using geospatial and statistical analyses, this research compares census-tract level socioeconomic data on specific demographic characteristics (minority population, low education, population density and income) with the spatial location of New Hampshire compensatory mitigation program sites. Census tracts are analyzed according to groupings at the state level and for two service areas with different population densities: the Merrimack and Middle Connecticut Service Areas. This research also applies a geospatial approach to recommend areas where outreach could be expanded to increase environmental justice communities’ participation in the ARM fund. Consistent with previous compensatory mitigation and environmental justice literature, this research finds demographic characteristics are an important consideration for environmental justice. At the statewide census-tract level, I find that populations around mitigation sites are more likely to have a lower percentage of nonwhite populations, lower population density, and higher income, as compared to sites without mitigation sites. Populations around permit sites are also likely to have lower population densities. I also find that this level of analysis is important to recognize inequalities and inform natural resource management decisions. In contrast, to the statewide results, I find significant demographic differences within the relatively low population density Middle Connecticut region. For the Merrimack region, which is larger and more diverse, results are similar to the statewide analysis: I find that populations around mitigation sites are more likely to have a lower percentage of nonwhite populations. Unlike the statewide analysis, I find that populations around mitigation sites are more likely to have lower educational attainment and populations around permit sites are more likely to have higher incomes. Then, I identified 26 environmental justice communities with aquatic restoration opportunities and found that almost half of these communities have participated in the ARM fund by submitting proposals to receive mitigation funding. Using an optimizing hot spot analysis and a heat map, I identified three environmental justice communities that have experienced significant wetland loss and to which the ARM Fund could target outreach: Manchester, Dover and Newington. This thesis research is intended to provide guidance to state agencies, cities and towns, nongovernmental organizations, and others interested in advancing protection of New Hampshire’s aquatic resources. The analytic methods contribute to broader research into the human dimensions of water policy

Usage de la cognition spatiale pour localiser les lieux d'activité lors d'une enquête Origine - Destination

Ce mémoire cerne la problématique de la description qualitative de la localisation d'un lieu décrit en langage naturel. C'est par une approche cognitive qu'est abordé successivement l'apprentissage de l'espace, le stockage de l'information et la restitution de l'information en langage naturel, par l'entremise des concepts de méronymie, de catégories hiérarchiques et de référents spatiaux. De ce cadre théorique, on propose de restructurer une base de données de lieux existants en y ajoutant des paramètres qui permettent de retrouver, d'une description en langage naturel précise ou floue, un lieu sans ambigüité dans une base de données grâce à une interface usager offrant divers modes de repérage spatial

Um sistema de informação espaço-temporal para objectos móveis

Dissertação de mestrado integrado em Engenharia de ComunicaçõesA grande evolução tecnológica tanto dos Sistemas de Informação Geográfica (SIG) bem como das tecnologias de localização (GPS, WI-FI, RFID) contribuíram para um significativo aumento da recolha de dados espaciais. Devido a esta proliferação e às grandes quantidades de dados que são recolhidos, são necessárias bases de dados e mecanismos apropriados para o seu armazenamento e sua respectiva análise. No passado, o desenho de sistemas de informação para objectos móveis basearam-se muitas vezes em abordagens (aplicações) restritas a tecnologias de localização específicas, levando a um vasto leque de modelos de dados, modelos de base de dados e respectivas funcionalidades. Para superar esta proliferação de modelos, este projecto propõe um sistema de informação espaço-temporal independente do domínio de aplicação, e com o intuito de se abstrair da tecnologia de posicionamento utilizada para a recolha de dados. Este sistema de informação espaço-temporal visa o desenvolvimento de um sistema de armazenamento, análise e visualização de dados sobre objectos móveis capazes de representar e armazenar dados com características espaciais e de realizar análises sobre os mesmos. Este sistema é intitulado STAR e integra três componentes principais, as bases de dados espaçotemporais, os SIG e os dados espaço-temporais. A base de dados espaço-temporal desenhada permite o armazenamento dos dados espaço-temporais bem como o armazenamento da geometria do espaço no qual ocorre o movimento. Esta geometria é representada por pontos, linhas e/ou polígonos. Os SIG auxiliam os processos de análise e visualizações de dados. Os dados espaço-temporais são intitulados neste projecto de objectos móveis, podendo o movimento dos mesmos ser analisado no STAR. Os resultados alcançados são promissores na demonstração de como o sistema é capaz de armazenar dados de posicionamento com formatos diferentes, e na aplicação de análises, visualizações e representações sobre os mesmos.The huge technological evolution of both the Geographic Information Systems (GIS) as well as location technologies (GPS, Wi-Fi, RFID) contributes to a large increase in spatial data collection. Because of this proliferation and to the large amounts of data that are collected, databases and appropriate mechanisms for their storage and their analysis are necessary. In the past, the design of information systems for moving objects was often based on approaches (applications) restricted to specific location technologies, leading to a wide range of data models, database models and functionalities. To overcome this proliferation of models, this project proposes a spatio-temporal information system that is independent of the application domain and that abstract the positioning technology used for data collection. This spatio-temporal information system aims the development of a storage system with data analysis and visualization mechanism for moving objects that can represent and store data with spatial characteristics and perform spatial analysis on them. This system is named STAR and incorporates three main components, spatio-temporal databases, GIS and spatio-temporal data. The designed spatio-temporal database enables the storage of the spatio-temporal data and the geometry of the space in which the movement occurs. This geometry is represented by points, lines and/or polygons. The GIS help the processes of analysis and visualization of data. The spatio-temporal data in this project are entitled to moving objects, their movement can be analysed in STAR. The results obtained so far are promising in demonstrating how the system is capable of storing positioning data with different formats, and in applying analysis, visualizations and different representations of the analysed data

STAR : um sistema de armazenamento, análise e visualização de dados sobre o movimento humano

Dissertação de mestrado em Engenharia e Gestão de Sistemas de InformaçãoA análise do movimento no espaço é uma tarefa complexa que implica a integração de conhecimentos de áreas como a física, geografia ou psicologia. Nesta tarefa complexa, questões que abordam como o movimento num determinado espaço é possível ou como o movimento é limitado por determinados eventos ou obstáculos que aparecem no espaço precisam de ser investigadas. Com o objectivo de realizar análises aos dados sobre o movimento que permitam identificar determinados padrões, apresenta-se neste trabalho a concepção, implementação e validação de um sistema de informação de apoio à recolha, visualização e análise desses dados. O STAR, o sistema descrito neste trabalho, está relacionado com três temas principais, as bases de dados espaciais, os sistemas de informação geográfica e o movimento humano. As bases de dados espaciais desenhadas, permitem o armazenamento dos dados recolhidos através de dispositivos de posicionamento, e ainda, o armazenamento da geometria do espaço no qual ocorre o movimento representado por pontos, linhas e/ou polígonos. Os sistemas de informação geográfica auxiliam o processo de visualização e análise dos dados recolhidos. O movimento humano, mais especificamente, o movimento de pedestres, é a área de aplicação testada pelo STAR. Este trabalho começa com a caracterização do estado da arte através do levantamento de um conjunto de fundamentos teóricos associados aos temas referidos. Posteriormente, são apresentadas as funcionalidades e a arquitectura do STAR. O trabalho prossegue com a definição de um modelo de dados para o sistema proposto, o qual é representado recorrendo a diagramas de classe. Seguidamente, e associado à implementação do STAR, são demonstradas as diversas funcionalidade implementadas. O sistema foi testado através da análise de conjuntos de dados associados ao movimento de pedestres. Os resultados obtidos permitem concluir que o STAR é capaz de armazenar, analisar e visualizar os dados sobre o movimento, sendo uma ferramenta de suporte ao estudo e compreensão da forma como as pessoas se movimentam no espaço.The analysis of movement in space is a complex task that requires the integration of knowledge from several areas, such as physics, geography or psychology. In this complex task, issues like how movement in space is possible and how movement is constrained by events or obstacles that appear in space need to be investigated. In order to analyze movement data that allows the identification of patterns or trends, this work presents the design, implementation and validation of an information system that supports the collection, analysis and visualization of such data. The system described in this work, STAR, is related with three main areas, spatial databases, geographic information systems and human movement. The designed spatial database allows for the storage of data collected by positioning devices, and also, the storage of the geometry of the space in which movement occurs. This geometry is represented by points, lines or polygons. The geographic information systems help the process of visualization and analysis of the collected data. The human movement, more specifically, the movement of pedestrians, represents the application area used to evaluate the STAR system. This work begins with the characterization of the state of the art by surveying a set of theoretical principles associated with these themes. Subsequently, this work presents the envisaged functionalities and architecture of STAR. The data model for the proposed system is also presented using class diagrams. After the description of the functionalities, architecture and database model, the implemented functionalities are shown analyzing two datasets associated with the movement of pedestrians. The obtained results show that the STAR system is able to store, analyze and visualize data about movement, being a tool that can be used to support the study and understanding of how people move in space

Implementation des ATKIS in GIS mit relationaler Attributverwaltung unter dem Aspekt der Fortführung

Das Amtliche Topographisch-Kartographische Informationssystem (ATKIS) ist ein Vorhaben der Landesvermessungsverwaltungen der Bundesrepublik Deutschland zum Aufbau digitaler Landschaftmodelle (DLM) und digitaler Kartenmodelle (DKM). In der Arbeit werden zunächst die Grundideen von ATKIS und von temporalen Datenmodellen dargestellt. Auf Grund einer Analyse des ATKIS-Objektartenkatalogs wurde ein Metainformationssystem DST entwickelt und mit Unterstützung des Instituts für Angewandte Geodäsie / Außenstelle Leipzig (IfAG) praktisch eingeführt. Weiterhin wurden Vorschläge für temporale Erweiterungen des DLM unterbreitet, die insbesondere die Gewinnung inkrementeller Fortführungsinformationen unterstützen

Anfrageoptimierung in objektrelationalen Datenbanken durch kostenbedingte Termersetzungen

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Formal extension of the relational model for the management of spatial and spatio-temporal data

[Resumen] En los últioms años, se ha realizado un gran esfuerzo investigador en la manipulación de datos especiales y Sistemas de Información Geográfica (SIG). Una clara limitación de las primeras aproximaciones es la falta de integración entre datos geográficos y alfanuméricos. Para resolver esto surge el área de Bases de Datos Espaciales. Los problemas que aparecen en este campo son muchos y complejos. Un primer ejemplo son las peculiaridades de las operaciones espaciales, como el calculo de la intersección espacial de dos superficies. Otro ejemplo es el elegir las estructuras de datos apropiadas (relaciones, capas, etc.) y el conjunto de operaciones adeucado. La combinación con las Bases de Datos Temporales da lugar a las Bases de Datos Espacio-temporales, en las que la inclusión de la dimensión temporal complica más los problemas anteriores. A pesar de la gran cantidad de aproximaciones propuestas, no se ha llegado todavía a una solución satisfactoria. La presente tesis propone una nueva solución que resuelve todos los problemas de modelado de datos espaciales y espacio-temporales resaltados arriba. Parte del trabajo se completó durante el proyecto ""CHOROCRONOS"": A Research Network for Saptiotemporal Database Systems"", financiado por la Unión Europea. El modelo propuesto en la tesis define tres tipos de dato punto, línea y superficie, que encajan perfectamente en la percepción humana. La definición de estos tipos de dato se basa en la definición previa de Quanta Espacial. Las estructuras de datos usadas son las relaciones no anidadas de modelo relacional puro. El conjunto de operaciones relacionales permite alcanzar casi por completo la funcionalidad propuesta en otros modelos. Todas las operaciones han sido definidas en base a un núcleo reducido de operaciones primitvas. Todos los tipos de datos, espaciales, espacio-temporales y convencionales se manipulan de forma uniforme con este conjunto de operaciones

Resolving semantic conflicts through ontological layering

We examine the problem of semantic interoperability in modern software systems, which exhibit pervasiveness, a range of heterogeneities and in particular, semantic heterogeneity of data models which are built upon ubiquitous data repositories. We investigate whether we can build ontologies upon heterogeneous data repositories in order to resolve semantic conflicts in them, and achieve their semantic interoperability. We propose a layered software architecture, which accommodates in its core, ontological layering, resulting in a Generic ontology for Context aware, Interoperable and Data sharing (Go-CID) software applications. The software architecture supports retrievals from various data repositories and resolves semantic conflicts which arise from heterogeneities inherent in them. It allows extendibility of heterogeneous data repositories through ontological layering, whilst preserving the autonomy of their individual elements. Our specific ontological layering for interoperable data repositories is based on clearly defined reasoning mechanisms in order to perform ontology mappings. The reasoning mechanisms depend on the user‟s involvments in retrievals of and types of semantic conflicts, which we have to resolve after identifying semantically related data. Ontologies are described in terms of ontological concepts and their semantic roles that make the types of semantic conflicts explicit. We contextualise semantically related data through our own categorisation of semantic conflicts and their degrees of similarities. Our software architecture has been tested through a case study of retrievals of semantically related data across repositories in pervasive healthcare and deployed with Semantic Web technology. The extensions to the research results include the applicability of our ontological layering and reasoning mechanisms in various problem domains and in environments where we need to (i) establish if and when we have overlapping “semantics”, and (ii) infer/assert a correct set of “semantics” which can support any decision making in such domains