Infrastructure Engineering - Theses
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ItemTechnical and financial feasibility of a solar dryer in Bhutan( 2005)The technical and financial performance of an existing solar crop dryer at Khao-kor, Thailand has been evaluated for possible replication in Bhutan. The complete dryer system has been modelled using TRNSYS and the collector area was optimised to give minimum drying cost. From the evaluation, the average collector, pick-up and system efficiencies were found as 44%, 23% and 18% respectively. The solar contribution to the load is 33% when the dryer is used for 304 days in a year. Chilli and beef were selected as products to be dried as they are an integral part of Bhutan’s dishes. The drying cost is US $ 7.94 and 5.96 per kg of dry matter for chilli and beef respectively using the solar dryer system. The corresponding costs using an electric heating system is US $ 7.76 and 6.25 per kg of dry matter for chilli and beef respectively. The solar dryer system was found to be cheaper compared to an electric heating system, however, from the commercial point of view, without any incentives, both the systems are financially non-viable in Bhutan. Nevertheless, the solar dryer system is more attractive than the electric heating system as its NPV at 13% real discount rate is higher.
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ItemA multi-purpose cadastre prototype on the web( 2000-08)The Multi-Purpose Cadastre concept has been discussed over the last three decades. The concept, although idealistic when conceived, is still regarded as visionary in addressing the inherent limitations of most modern geo-spatial systems, especially cadastral systems worldwide. The concept is being used to better disseminate and utilise the increasingly large amount of data contained in many of the geo-spatial databases developed over the last few years. The utilisation of the World Wide Web has allowed these geo-spatial systems to evolve into online ‘virtual’ systems that are accessible by most people with the appropriate tools (the computers and telephone lines). This thesis analysed the growing development of these online systems. It describes a review of online cadastral systems that revealed the similarities in moving towards the future vision of cadastral systems of the 21st century, as highlighted by the International Federation of Surveyors document, Cadastre 2014. The rapidly growing volume of geo-spatial data, which has been attributed by technologies such as remote sensing and Global Positioning Systems, are impacting on the way societies of today, are using, viewing and storing geo-spatial data. Improvements in related areas such as the Spatial Data Infrastructure, the Open GIS Consortium and the Australian World Wide Web Mapping Consortium are described and discussed in this thesis.
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ItemPneumatic separation of grain from straw and chaff in the combine harvester( 1970)The riddle mechanism, used to clean threshed grain in harvesting machinery, has remained basically unchanged for over a century. The desired function and throughput of the cleaning mechanism in a harvester is discussed, together with the effectiveness of the conventional system. The published work on a combined harvester is reviewed; the history and development of the various components leading to their present configurations is examined together with work done on developing alternatives to the usual components in a harvester. Pneumatic separation in a vertical air stream, proposed as an alternative to the riddle system of cleaning the efflux from the threshing system of a harvester, is examined in depth. Theoretical prediction of the performance of a vertical air stream, as a separator, is shown to be intractable while predictions of separation based on terminal velocities of all the types of particles present in the mixture (which were measured fully) are shown to provide only a fair indication of likely performance. A small pneumatic separator was designed and built; the performance of this unit was investigated in detail; the effects of air velocity, feed rate, and of material composition are discussed. Likely ways of improving separation, together with the lines along which further investigations should be conducted, are discussed using the results obtained from the separation tests.
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ItemDeveloping a user generated method to add landmarks to Openstreetmap( 2011)The essential role of landmarks in human way finding motivated researchers to investigate options of integrating landmarks in navigation systems to generate automatic instructions that are close to human instructions. Theses attempts usually define methods to select landmarks from various datasets including cadastral maps and yellow pages. However, landmark selection in a volunteered geographic information database has never been tried before. In this research, Openstreetmap is used as a volunteered geographic information dataset to be used for adding landmarks. It is proposed to add landmarks with a user-generated method to Openstreetmap. A system is designed for this purpose and is tested in adding landmarks to Openstreetmap.
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ItemThe relative benefit of reliable heading updates on urban wayfinding( 2010)Prior research about wayfinding has found that females tend to employ a single strategy based on landmarks, where males are more versatile, using a dual strategy of landmarks and global orientation information such as cardinal directions (Lawton, 2010). It was proposed that this difference occurs due to males’ better sense of direction, which would deliver more trustworthy indications of current heading. Since males’ versatility has often been linked with better navigation performance (for example Sandstrom, Kaufman, & Huettel, 1998; Saucier et al., 2002) this study sought to contribute to the growing body of literature on methods of training to increase sense of direction (such as Hund and Minarik, 2006; Hund & Nazarczuk, 2009). An experimental procedure was used to investigate the possibility that the provision of reliable cardinal direction heading updates to participants would lead to a dual strategy for orientation in those that usually use a single strategy based on landmarks. This was done in an urban navigation context, with the main dependent variable being level of recall for route structure. Using the Santa Barbara Sense of Direction Scale, the study revealed that males had a higher self-reported sense of direction than females. Additionally, no sex differences in performance were found on the route structure recall tasks. Rather than being due to females’ use of a dual wayfinding strategy, however, this was interpreted as an artefact of the use of a video in the procedure, which involved watching someone else navigating along a route. This is supported by another finding, that conditions containing cardinal directions or landmark spatial references did not produce higher route structure recall than the control condition. Since the procedure did not require participants to navigate through a real, or virtual, environment, it may not have been perceived as a disorientation threat. Due to this, they may not have employed wayfinding strategies, accounting for the poor influence of the spatial reference conditions and the lack of sex difference. The study is therefore viewed as an ideal candidate for replication by future investigators, who may wish to compare performance using a task where participants are required to deploy wayfinding strategies.
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ItemIndoor centrality( 2009)Indoor environments are different from other environments. There are some characteristics which are unique such as dimensionality and spatial structure. Apart from indoor centrality, research has been done to reveal the properties of centrality particularly in street networks, social networks, and biological networks. In addition, there are some indoor representations which have already been developed for different purposes such as wayfinding, behavioural science, and sociology.Therefore, this research is undertaken to investigate models of representation and apply the measures of centrality to reveal the properties of indoor environments. Different representations and betweenness centrality measures have been tested in a subset of indoor environments. The models and measures have been proven capable of revealing the properties of indoor environments such as centrality, prominency, and complexity. In addition, this research has revealed the strengths and weaknesses of both models and measures. The results of different measurements of betweenness centrality based on different representations are combined. Here, graph representations which depict space and link centralities in topological graphs is used to construct a structural hierarchy which is able to support wayfinding in indoor environments. This research contributes to our understanding of indoor centrality through the formalization of the representations and measures.