Abstract

Abstract
Point Set Registration (PSR) algorithms have very different underlying theoretical models to define a process that calculates the alignment solution between two point clouds. The selection of a particular PSR algorithm can be based on the efficiency (time to compute the alignment) and accuracy (a measure of error using the estimated alignment). In our specific context, previous work used a CPD algorithm to detect and quantify change in spatiotemporal datasets composed of moving and shape-changing objects represented by a sequence of time stamped 2D polygon boundaries. Though the results were promising, we question if the selection of a particular PSR algorithm influences the results of detection and quantification of change. In this work we review and compare several PSR algorithms, characterize test datasets and used metrics, and perform tests for the selected datasets. The results show pyCPD and cyCPD implementations of CPD to be good alternatives and that BCPD can have potential to be yet another alternative. The results also show that detection and quantification accuracy change for some of the tested PSR implementations.

Abstract

Abstract
This paper deals with the design and implementation of a data model and operations for dealing with continuously changing spatial data in object-relational DBMS. The data model relies on abstract data types but we introduce modifications to the internal structure of the spatiotemporal data representations proposed in the literature, to reduce storage requirements and to enable the reutilization of data during the execution of the queries. We show how to implement spatiotemporal operations relying on the spatial functions released by the underlying DBMS and how to use the alternative data representations to reduce the volume of temporary data created in the evaluation of spatiotemporal operations. We also discuss on the advantages and disadvantages of the proposed solutions. © 2012 ACM.

Abstract
The revision process of a Municipal Master Plan has a sequence of several steps that are to be executed. One of these steps, public discussion, is of great democratic importance as it allows citizens to actively participate in the management of the municipality through proposals and public debates taking place at a specific time and location in accordance to a previously published agenda. With such a process running at Oporto's municipality, and with the aim of reaching as much citizens as possible through the removal of spatial and temporal constrains, an effort was made to develop an electronic service for citizens, to complement the usual methods of public participation. In this paper(1) we present the results of such service.

Abstract
SINUP consists of a geographical information system whose purpose is to store, in a coherent manner, data resulting from key activities of Oporto local authority, allowing to better structure the knowledge about the urban reality. In the possession of such knowledge, and with the revision of Oporto's Municipal Master Plan taking place soon, the municipality is making an effort to develop an electronic citizen service that will allow a large number of citizens to consult it, and more important, participate in its public discussion prior to approval thus creating a major instrument of e-democracy in Oporto's municipality.