Infrastructure Engineering - Research Publications
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ItemRIM: a ray intersection model for the analysis of the between relationship of spatial objects in a 2D plane(Taylor & Francis, 2020-07-07)The term between is frequently used to describe spatial arrangements of objects where one described core object is positioned in the space bounded by two or more peripheral objects. As such, the relation between involves spatial configurations of at least three spatial objects. However, most of the existing qualitative spatial reasoning models focus only on binary spatial relations, and there is currently no single model that enables adequate reasoning about this ternary spatial relation. This paper proposes a novel model for expressing nuanced spatial relationships between three spatial objects, called the Ray Intersection Model (RIM). RIM evaluates rays cast between two peripheral spatial objects, and their topological relations with the core object to determine its position relative to the peripheral objects. RIM leaves the binary classification of the core object as between/not between to the user and application context. Although RIM supports all types of 2D spatial objects (i.e. points, lines, and polygons), its expressiveness is demonstrated in this paper by analyzing the total of 28 distinct configurations of triplets of polygon objects in a 2D plane. RIM has been computationally implemented and we demonstrate how RIM can be applied to analyze the arrangements of buildings at a university campus.
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ItemExtracting interrogative intents and concepts from geo-analytic questions(Copernicus GmbH, 2020)Understanding syntactic and semantic structure of geographic questions is a necessary step towards true geographic question-answering (GeoQA) machines. The empirical basis for the understanding of the capabilities expected from GeoQA systems are geographic question corpora. Available corpora in English have been mostly drawn from generic Web search logs or limited user studies, supporting the focus of GeoQA systems on retrieving factoids: factual knowledge about particular places and everyday processes. Yet, the majority of questions enquired about in the spatial sciences go beyond simple place facts, with more complex analytical intents informing the questions. In this paper, we introduce a new corpus of geo-analytic questions drawn from English textbooks and scientific articles. We analyse and compare this corpus with two general-purpose GeoQA corpora in terms of grammatical complexity and semantic concepts, using a new parsing method that allows us to differentiate and quantify patterns of a question’s intent.
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ItemOrigin-Destination Flow Estimation from Link Count Data Only(MDPI, 2020-09)All established models in transportation engineering that estimate the numbers of trips between origins and destinations from vehicle counts use some form of a priori knowledge of the traffic. This paper, in contrast, presents a new origin-destination flow estimation model that uses only vehicle counts observed by traffic count sensors; it requires neither historical origin-destination trip data for the estimation nor any assumed distribution of flow. This approach utilises a method of statistical origin-destination flow estimation in computer networks, and transfers the principles to the domain of road traffic by applying transport-geographic constraints in order to keep traffic embedded in physical space. Being purely stochastic, our model overcomes the conceptual weaknesses of the existing models, and additionally estimates travel times of individual vehicles. The model has been implemented in a real-world road network in the city of Melbourne, Australia. The model was validated with simulated data and real-world observations from two different data sources. The validation results show that all the origin-destination flows were estimated with a good accuracy score using link count data only. Additionally, the estimated travel times by the model were close approximations to the observed travel times in the real world.
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ItemPlace facets: a systematic literature review(Taylor & Francis, 2020)Place is a central concept in geography and a topic of interest in the social sciences, urban planning, architecture, and most recently in information science. The notion of place has therefore been studied with different foci of interest. Consequently, heterogeneous terminologies, conceptualizations, models, and ontologies have been proposed to capture this elusive concept. Yet these studies complement each other. Utilizing the concept of place facet as a particular type of information about place, in this review paper we bridge these multidisciplinary studies about place. We collect the different facets of place introduced in the literature and synthesize place characteristics by categorizing the identified facets. Finally, we discuss future directions for place-related research.
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ItemDiscovery of topological constraints on spatial object classes using an extended topological model(University of Maine, 2019)In a typical data collection process, a surveyed spatial object is annotated upon creation, and is classified based on its attributes. This annotation can also be guided by textual definitions of objects. However, interpretations of such definitions may differ among people, and thus result in subjective and inconsistent classification of objects. This problem becomes even more pronounced if the cultural and linguistic differences are considered. As a solution, this paper investigates the role of topology as the defining characteristic of a class of spatial objects. We propose a data mining approach based on frequent itemset mining to learn patterns in topological relations between objects of a given class and other spatial objects. In order to capture topological relations between more than two (linear) objects, this paper further proposes an extension of the 9-intersection model for topological relations of line geometries. The discovered topological relations form topological constraints of an object class that can be used for spatial object classification. A case study has been carried out on bridges in the OSM dataset for the state of Victoria, Australia. The results show that the proposed approach can successfully learn topological constraints for the class bridge, and that the proposed extended topological model for line geometries outperforms the 9-intersection model in this task.
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ItemPlace questions and human-generated answers: A data analysis approach(Springer, Cham, 2020-01-01)This paper investigates place-related questions submitted to search systems and their human-generated answers. Place-based search is motivated by the need to identify places matching some criteria, to identify them in space or relative to other places, or to characterize the qualities of such places. Human place-related questions have thus far been insufficiently studied and differ strongly from typical keyword queries. They thus challenge today’s search engines providing only rudimentary geographic information retrieval support. We undertake an analysis of the patterns in place-based questions using a large-scale dataset of questions/answers, MS MARCO V2.1. The results of this study reveal patterns that can inform the design of conversational search systems and in-situ assistance systems, such as autonomous vehicles.
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ItemInitial Analysis of Simple Where-Questions and Human-Generated Answers(LIPIcs, 2019)Geographic questions are among the most frequently asked questions in Web search and question answering systems. While currently responses to the questions are machine-generated by document/snippet retrieval, in the future these responses will need to become more similar to answers provided by humans. Here, we have analyzed human answering behavior as response to simple where questions (i.e., where questions formulated only with one toponym) in terms of type, scale, and prominence of the places referred to. We have used the largest available machine comprehension dataset, MS-MARCO v2.1. This study uses an automatic approach for extraction, encoding and analysis of the questions and answers. Here, the distribution analysis are used to describe the relation between questions and their answers. The results of this study can inform the design of automatic question answering systems for generating useful responses to where questions.
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ItemConsiderations for Efficient Communication of Route Directions( 2006)We can observe that people familiar with an environment give route directions of varying granularity to other locals. Such route directions are typically shorter than the turn based directions of current navigation services, and contain only references of high relevance to the wayfinder. Studying these route directions of varying granularity reveals that they are intended to be memorized, a property that requires a low cognitive workload of the wayfinder during their usage. The short-term memory span of humans imposes a limit on the amount and the structure of information communicated. We argue that route directions of varying granularity provide the means to respect these limits by efficient recoding.
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ItemLandmark hierarchies in context(SAGE PUBLICATIONS LTD, 2008-05)We are interested in the generation of distinguishing place or route descriptions for urban environments. Such descriptions require a hierarchical model of the discourse, the elements of the city. We postulate that cognitive hierarchies, as used in human communication, can be sufficiently reflected in machine-generated hierarchies. In this paper we (a) propose a computational model for the generation of a hierarchy of one of these elements of the city—landmarks—and (b) demonstrate that a set of filter rules applied on this hierarchy derives distinguishing route descriptions from spatial context.