Qualitative Spatial Configuration Queries Towards Next Generation Access Methods for GIS

For a long time survey, management, and provision of geographic information in Geographic Information Systems (GIS) have mainly had an authoritative nature. Today the trend is changing and such an authoritative geographic information source is now accompanied by a public and freely available one which is usually referred to as Volunteered Geographic Information (VGI). Actually, the term VGI does not refer only to the mere geographic information, but, more generally, to the whole process which assumes the engagement of volunteers to collect and maintain such information in freely accessible GIS. The quick spread of VGI gives new relevance to a well-known challenge: developing new methods and techniques to ease down the interaction between users and GIS. Indeed, in spite of continuous improvements, GIS mainly provide interfaces tailored for experts, denying the casual user usually a non-expert the possibility to access VGI information. One main obstacle resides in the different ways GIS and humans deal with spatial information: GIS mainly encode spatial information in a quantitative format, whereas human beings typically prefer a qualitative and relational approach. For example, we use expressions like the lake is to the right-hand side of the wood or is there a supermarket close to the university? which qualitatively locate a spatial entity with respect to another. Nowadays, such a gap in representation has to be plugged by the user, who has to learn about the system structure and to encode his requests in a form suitable to the system. Contrarily, enabling gis to explicitly deal with qualitative spatial information allows for shifting the translation effort to the system side. Thus, to facilitate the interaction with human beings, GIS have to be enhanced with tools for efficiently handling qualitative spatial information. The work presented in this thesis addresses the problem of enabling Qualitative Spatial Configuration Queries (QSCQs) in GIS. A QSCQ is a spatial database query which allows for an automatic mapping of spatial descriptions produced by humans: A user naturally expresses his request of spatial information by drawing a sketch map or producing a verbal description. The qualitative information conveyed by such descriptions is automatically extracted and encoded into a QSCQ. The focus of this work is on two main challenges: First, the development of a framework that allows for managing in a spatial database the variety of spatial aspects that might be enclosed in a spatial description produced by a human. Second, the conception of Qualitative Spatial Access Methods (QSAMs): algorithms and data structures tailored for efficiently solving QSCQs. The main objective of a QSAM is that of countering the exponential explosion in terms of storage space occurring when switching from a quantitative to a qualitative spatial representation while keeping query response time acceptable

Physical Reasoning for Intelligent Agent in Simulated Environments

Developing Artificial Intelligence (AI) that is capable of understanding and interacting with the real world in a sophisticated way has long been a grand vision of AI. There is an increasing number of AI agents coming into our daily lives and assisting us with various daily tasks ranging from house cleaning to serving food in restaurants. While different tasks have different goals, the domains of the tasks all obey the physical rules (classic Newtonian physics) of the real world. To successfully interact with the physical world, an agent needs to be able to understand its surrounding environment, to predict the consequences of its actions and to draw plans that can achieve a goal without causing any unintended outcomes. Much of AI research over the past decades has been dedicated to specific sub-problems such as machine learning and computer vision, etc. Simply plugging in techniques from these subfields is far from creating a comprehensive AI agent that can work well in a physical environment. Instead, it requires an integration of methods from different AI areas that considers specific conditions and requirements of the physical environment. In this thesis, we identified several capabilities that are essential for AI to interact with the physical world, namely, visual perception, object detection, object tracking, action selection, and structure planning. As the real world is a highly complex environment, we started with developing these capabilities in virtual environments with realistic physics simulations. The central part of our methods is the combination of qualitative reasoning and standard techniques from different AI areas. For the visual perception capability, we developed a method that can infer spatial properties of rectangular objects from their minimum bounding rectangles. For the object detection capability, we developed a method that can detect unknown objects in a structure by reasoning about the stability of the structure. For the object tracking capability, we developed a method that can match perceptually indistinguishable objects in visual observations made before and after a physical impact. This method can identify spatial changes of objects in the physical event, and the result of matching can be used for learning the consequence of the impact. For the action selection capability, we developed a method that solves a hole-in-one problem that requires selecting an action out of an infinite number of actions with unknown consequences. For the structure planning capability, we developed a method that can arrange objects to form a stable and robust structure by reasoning about structural stability and robustness

Schematisation in Hard-copy Tactile Orientation Maps

This dissertation investigates schematisation of computer-generated tactile orientation maps that support mediation of spatial knowledge of unknown urban environments. Computergenerated tactile orientation maps are designed to provide the blind with an overall impression of their surroundings. Their details are displayed by means of elevated features that are created by embossers and can be distinguished by touch. The initial observation of this dissertation states that only very little information is actually transported through tactile maps owing to the coarse resolution of tactual senses and the cognitive effort involved in the serial exploration of tactile maps. However, the differences between computer-generated, embossed tactile maps and manufactured, deep-drawn tactile maps are significant. Therefore the possibilities and confines of communicating information through tactile maps produced with embossers is a primary area of research. This dissertation has been able to demonstrate that the quality of embossed prints is an almost equal alternative to traditionally manufactured deep-drawn maps. Their great advantage is fast and individual production and (apart from the initial procurement costs for the printer)low price, accessibility and easy understanding without the need of prior time-consuming training. Simplification of tactile maps is essential, even more so than in other maps. It can be achieved by selecting a limited number from all map elements available. Qualitative simplification through schematisation may present an additional option to simplification through quantitative selection. In this context schematisation is understood as cognitively motivated simplification of geometry and synchronised maintenance of topology. Rather than further reducing the number of displayed objects, the investigation concentrates on how the presentation of different forms of streets (natural vs. straightened) and junctions (natural vs. prototypical) affects the transfer of knowledge. In a second area of research, a thesis establishes that qualitative simplification of tactile orientation maps through schematisation can enhance their usability and make them easier to understand than maps that have not been schematised. The dissertation shows that simplifying street forms and limiting them to prototypical junctions does not only accelerate map exploration but also has a beneficial influence on retention performance. The majority of participants that took part in the investigation selected a combination of both as their preferred display option. Tactile maps that have to be tediously explored through touch, uncovering every detail, complicate attaining a first impression or an overall perception. A third area of research is examined, establishing which means could facilitate map readersâ options to discover certain objects on the map quickly and without possessing a complete overview. Three types of aids are examined: guiding lines leading from the frame of the map to the object, position indicators represented by position markers at the frame of the map and coordinate specifications found within a grid on the map. The dissertation shows that all three varieties can be realised by embossers. Although a guiding line proves to be fast in size A4 tactile maps containing only one target object and few distracting objects, it also impedes further exploration of the map (similar to the grid). In the following, advantages and drawbacks of the various aids in this and other applications are discussed. In conclusion the dissertation elaborates on the linking points of all three examinations. They connect and it is argued that cognitively motivated simplification should be a principle of construction for embossed tactile orientation maps in order to support their use and comprehension. A summary establishes the recommendations that result from this dissertation regarding construction of tactile orientation maps considering the limitations through embosser constraints. Then I deliberate how to adapt schematisation of other maps contingent to intended function, previous knowledge of the map reader, and the relation between the time in which knowledge is acquired and the time it is employed. Closing the dissertation, I provide an insight into its confines and deductions and finish with a prospective view to possible transfers of the findings to other applications, e.g. multimedia or interactive maps on pin-matrix displays and devices

Learning cognitive maps: Finding useful structure in an uncertain world

In this chapter we will describe the central mechanisms that influence how people learn about large-scale space. We will focus particularly on how these mechanisms enable people to effectively cope with both the uncertainty inherent in a constantly changing world and also with the high information content of natural environments. The major lessons are that humans get by with a less is more approach to building structure, and that they are able to quickly adapt to environmental changes thanks to a range of general purpose mechanisms. By looking at abstract principles, instead of concrete implementation details, it is shown that the study of human learning can provide valuable lessons for robotics. Finally, these issues are discussed in the context of an implementation on a mobile robot. © 2007 Springer-Verlag Berlin Heidelberg

Building Complex and Site Categorization Using Similarity to a Prototypical Site

This project presents an assessment tool for classifying building complexes using sitebased relationships as calculated from ArcGIS 9.2 using model builder and Python scripting. Anthropogenic features extracted from imagery often form the foundation of spatial databases. These data are in turn used to inform situational awareness for relief, law enforcement, and military agencies among many others. Buildings and the complexes they form are critical features within the landscape. The categorization of complexes requires an understanding of the relationships of the buildings within the site. In this study, building complexes in California were assessed for similarity to a prototypical California high school defined with a training set of known high schools and compared to a set of uncategorized sites. Eighty-eight percent of the high schools were correctly classified as being highly similar to the control data set

A qualitative calculus for moving point objects constrained by networks

Continu bewegende objecten vormen een belangrijk studieobject in een groot aantal domeinen. Enkele voorbeelden zijn: een bioloog die het verplaatsinggedrag van een kudde dieren wil bestuderen, een verkeersplanner die de bewegingen van auto’s wil volgen en een sportwetenschapper die de onderlinge interacties van voetballers tijdens een wedstrijd wil analyseren. Vanuit geometrisch standpunt, concentreren de meeste toepassingen zich op de positionele beweging van het voorwerp zelf waardoor bewegende objecten meestal tot punten worden vereenvoudigd. De recente evoluties in diverse plaatsbepalingstechnieken (GPS, GSM, ...) laten toe grote hoeveelheden dergelijke bewegende puntobjecten op te meten en op te slaan. Er is al heel wat onderzoek verricht in het genereren, indexeren, en modelleren en bevragen van bewegende objecten in tijdruimtelijke databanken. Redeneren over de relaties tussen bewegende puntobjecten echter vormt nog maar sinds kort het voorwerp van onderzoek, vooral het redeneren binnen een kwalitatief kader. Nieuwe technieken binnen informatiesystemen, zoals Geografische Informatiesystemen (GIS), zouden echter veel meer kwalitatieve methodes moeten hanteren. Aangezien mensen verkiezen te communiceren in kwalitatieve termen, zouden dergelijke systemen dichter komen bij de manier waarop informatie wordt meegedeeld. Wat GIS betreft, passen deze ideeën volledig binnen het onderzoeksdomein van de Naïeve Geografie (Naive Geography). Door hun populariteit, wordt een GIS niet alleen meer door domeinspecialisten gebruikt (b.v. Google Earth, systemen voor autonavigatie). Het gebruik van kwalitatieve methodes binnen informatiesystemen zou de toegankelijkheid moeten verzekeren voor een brede waaier gebruikers. Aangezien redeneren over bewegingen een belangrijk onderdeel vormt van het alledaagse menselijke kennisvermogen, is er een duidelijke behoefte om een kwalitatieve ‘bewegingscalculus’ te ontwikkelen. In het domein van kwalitatief ruimtelijk redeneren is Mereotopologie het meest onderzochte studiegebied. Volgens het 9-Intersectie Model (9-Intersection Model) echter zijn er slechts twee triviale topologische relaties tussen twee puntobjecten: de objecten zijn ofwel co-incident ofwel disjunct. Aangezien bewegende objecten in de realiteit meestal niet samenvallen, en topologische modellen geen verder onderscheid kunnen maken tussen disjuncte objecten, zijn deze calculi in het geval van bewegende puntobjecten niet expressief genoeg. Een typisch voorbeeld is het geval waar twee vliegtuigen zich in een gescheiden relatie bevinden. Het is noodzakelijk om te weten of deze beide vliegtuigen in deze relatie kunnen blijven, zoniet kunnen de gevolgen catastrofaal zijn. De Kwalitatieve Traject Calculus (Qualitative Trajectory Calculus: QTC), geïntroduceerd door Van de Weghe, is op dit vlak expressiever. QTC beschrijft en redeneert over kwalitatieve relaties tussen disjuncte continu bewegende puntobjecten. In Van de Weghe, worden twee soorten QTC geïntroduceerd. De basiscalculus (QTC-Basic: QTCB) beschrijft de onderlinge relaties tussen bewegende puntobjecten met behulp van afstandsvergelijkingen, terwijl QTC-Dubbel Kruis (QTC-Double Cross: QTCC) de relaties beschrijft via een referentieframe bestaande uit drie referentielijnen in de vorm van een dubbel kruis. Moreira et al. maken een onderscheid tussen twee soorten bewegende objecten: voorwerpen die in de vrije ruimte kunnen bewegen (b.v. een vogel die door de lucht vliegt) en voorwerpen die in hun bewegingsvrijheid beperkt worden (b.v. een trein kan enkel op het spoorwegnetwerk bewegen). Een groot aantal bewegingen worden duidelijk begrensd door een netwerk (binnenschepen kunnen enkel varen op kanalen en sommige rivieren, auto’s rijden op straatnetwerken, enz.). Daarom is de hoofddoelstelling van dit proefschrift het uitbreiden van de QTC theorie naar objecten die enkel op netwerken kunnen bewegen. Met andere woorden, het doel is een kwalitatieve calculus op te stellen die het mogelijk maakt om relaties tussen bewegende puntobjecten die enkel op netwerken kunnen bewegen te beschrijven en te onderzoeken: De Kwalitative Traject Caculus op Netwerken (QTCN). Een tweede doelstelling bestaat erin om een eerste aanzet te geven tot de taalkundige en cognitieve bruikbaarheid en geschiktheid van QTC

BoR: Bag-of-Relations for Symbol Retrieval

International audienceIn this paper, we address a new scheme for symbol retrieval based on bag-of-relations (BoRs) which are computed between extracted visual primitives (e.g. circle and corner). Our features consist of pairwise spatial relations from all possible combinations of individual visual primitives. The key characteristic of the overall process is to use topological relation information indexed in bags-of-relations and use this for recognition. As a consequence, directional relation matching takes place only with those candidates having similar topological configurations. A comprehensive study is made by using several different well known datasets such as GREC, FRESH and SESYD, and includes a comparison with state-of-the-art descriptors. Experiments provide interesting results on symbol spotting and other user-friendly symbol retrieval applications