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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The geometric correction and registration of airborne line-scanned imagery for temporal thermal studies

Gregory, Simon January 2001 (has links)
This thesis begins by providing a review of techniques for interpreting the thermal response at the earth's surface acquired using remote sensing technology. Historic limitations in the precision with which imagery acquired from airborne platforms can be geometrically corrected and co-registered has meant that relatively little work has been carried out examining the diurnal variation of surface temperature over wide regions. Although emerging remote sensing systems provide the potential to register temporal image data within satisfactory levels of accuracy, this technology is still not widely available and does not address the issue of historic data sets which cannot be rectified using conventional parametric approaches. In overcoming these problems, the second part of this thesis describes the development of an alternative approach for rectifying airborne line-scanned imagery. The underlying assumption that scan lines within the imagery are straight greatly reduces the number of ground control points required to describe the image geometry. Furthermore, the use of pattern matching procedures to identify geometric disparities between raw line-scanned imagery and corresponding aerial photography enables the correction procedure to be almost fully automated. By reconstructing the raw image data on a truly line-by-line basis, it is possible to register the airborne line-scanned imagery to the aerial photography with an average accuracy of better than one pixel. Providing corresponding aerial photography is available, this approach can be applied in the absence of platform altitude information allowing multi-temporal data sets to be corrected and registered.
2

The water use rates of reedbed and wet woodland habitats

Read, K. E. January 2003 (has links)
To create hydrologically sustainable wetlands, knowledge of the water use requirements of target habitats must be known. Extensive literature reviews highlighted a dearth of water-use data associated with large reedbeds and wet woodland habitats and in response to this field experiments were established. Field experiments to measure the water use rates of large reedbeds [ET(Reed)] were completed at three sites within the UK. Reference Crop Evapotranspiration [ETo] was calculated and mean monthly crop coefficients [Kc(Reed)] were developed. Kc(Reed) was less than 1 during the growing season (March to September), ranging between 0.22 in March and reaching a peak of 0.98 in June. The developed coefficients compare favourably with published data from other large reedbed systems and support the premise that the water use of large reedbeds is lower than that from small/fringe reedbeds. A methodology for determining water use rates from wet woodland habitats (UK NVC Code: W6) is presented, in addition to provisional ET(W6) rates for two sites in the UK. Reference Crop Evapotranspiration [ETo] data was used to develop Kc(W6) values which ranged between 0.89 (LV Lysimeter 1) and 1.64 (CH Lysimeter 2) for the period March to September. The data are comparable with relevant published data and show that the water use rates of wet woodland are higher than most other wetland habitats. Initial observations suggest that water use is related to the habitat’s establishment phase and the age and size of the canopy tree species. A theoretical case study presents crop coefficients associated with wetland habitats and provides an example water budget for the creation of a wetland comprising a mosaic of wetland habitats. The case study shows the critical role that the water use of wetland habitats plays within a water budget.
3

Abrasion resistance of fibre reinforced concrete floors

Vassou, Vassoulla January 2003 (has links)
This thesis focuses on the investigation of the abrasion resistance of fibre reinforced concrete floors at both the macro and micro levels. A literature review of the available literature concerning subjects allied to the current project is included. This highlights themes relevant to wear mechanisms and the factors influencing it: factors that affect the abrasion resistance of concrete and several test methods for assessing it; and the historical development of fibres and the properties of different fibre types and their influence on concrete. Three accelerated abrasion testers were compared and critically discussed for their suitability for assessing the abrasion resistance of concrete floors. Based on the experimental findings one accelerated abrasion apparatus was selected as more appropriate to be used for carrying out the main investigations. The laboratory programme that followed was undertaken to investigate the influence of various material and construction factors on abrasion resistance. These included mix variations (w/c ratio), fibre reinforcement, geometry, type and volume, curing method and superplasticizing agents. The results clearly show that these factors significantly affected abrasion resistance and several mechanisms were presumed to explain and better understand these observations. To verify and understand these mechanisms that are accountable for the breakdown of concrete slabs, the same concrete specimens that were used for the macro-study, were also subjected to microstructutural investigations using techniques such as Microhardness examination, Mercury intrusion porosimetry and Petrographic examination. It has been found that the abrasion resistance of concrete is primarily dependent on the microstructure and porosity of the concrete nearest to the surface. The feasibility of predicting the abrasion resistance of fibre reinforced concrete floors by indirect and non-destructive methods was investigated using five methods that have frequently been used for assessing the quality of concrete. They included the initial surface absorption test, the impact test, ball cratering, the scratch test and the base hardness test. The impact resistance (BRE screed tester) and scratch resistance (Base hardness tester) were found to be the most sensitive to factors affecting abrasion resistance and hence are considered to be the most appropriate testing techniques.
4

The use of context in the classification of urban aerial imagery

Buchanan, A. J. January 2000 (has links)
Urban regions present some of the most challenging areas for the remote sensing community. Many different types of land cover have similar spectral responses, making them difficult to distinguish from one another. Traditional per-pixel classification techniques suffer particularly badly because they only use these spectral properties to determine a class, and no other properties of the image, such as context. This project presents the results of the classification of a deeply urban area of Dudley, West Midlands, using 4 methods: Supervised Maximum Likelihood, SMAP, ECHO and Unsupervised Maximum Likelihood. An accuracy assessment method is then developed to allow a fair representation of each procedure and a direct comparison between them. Subsequently, a classification procedure is developed that makes use of the context in the image, though a per-polygon classification. The imagery is broken up into a series of polygons extracted from the Marr-Hildreth zero-crossing edge detector. These polygons are then refined using a region-growing algorithm, and then classified according to the mean class of the fine polygons. The imagery produced by this technique is shown to be of better quality and of a higher accuracy than that of other conventional methods. Further refinements are suggested and examined to improve the aesthetic appearance of the imagery. Finally a comparison with the results produced from a previous study of the James Bridge catchment, in Darleston, West Midlands, is made, showing that the Polygon classified ATM imagery performs significantly better than the Maximum Likelihood classified videography used in the initial study, despite the presence of geometric correction errors.
5

Finite element analysis of particle impact problems

Wu, Chuan-Yu January 2001 (has links)
Particle impacts are of fundamental importance in many areas and there has been a renewed interest in research on particle impact problems. A comprehensive investigation of the particle impact problems, using finite element (FE) methods, is presented in this thesis. The capability of FE procedures for modelling particle impacts is demonstrated by excellent agreements between FE analysis results and previous theoretical, experimental and numerical results. For normal impacts of elastic particles, it is found that the energy loss due to stress wave propagation is negligible if it can reflect more than three times during the impact, for which Hertz theory provides a good prediction of impact behaviour provided that the contact deformation is sufficiently small. For normal impact of plastic particles, the energy loss due to stress wave propagation is also generally negligible so that the energy loss is mainly due to plastic deformation. Finite-deformation plastic impact is addressed in this thesis so that plastic impacts can be categorised into elastic-plastic impact and finite-deformation plastic impact. Criteria for the onset of finite-deformation plastic impacts are proposed in terms of impact velocity and material properties. It is found that the coefficient of restitution depends mainly upon the ratio of impact velocity to yield Vni/Vy0 for elastic-plastic impacts, but it is proportional to [(Vni/Vy0)*(Y/E*)]-1/2, where Y /E* is the representative yield strain for finite-deformation plastic impacts. A theoretical model for elastic-plastic impacts is also developed and compares favourably with FEA and previous experimental results. The effect of work hardening is also investigated.
6

The effect of catchment characteristics on sewage settling velocity grading

Tyack, J. N. January 1995 (has links)
A procedure has been developed which measures the settling velocity distribution of particles within a complete sewage sample. The development of the test method included observations of particle and liquid interaction using both synthetic media and sewage. Comparison studies with two other currently used settling velocity test procedures was undertaken. The method is suitable for use with either DWF or storm sewage. Information relating to the catchment characteristics of 35 No. wastewater treatment works was collected from the privatised water companies in England and Wales. 29 No. of these sites were used in an experimental programme to determine the settling velocity grading of 33 No. sewage samples. The collected data were analysed in an attempt to relate the settling velocity distribution to the characteristics of the contributing catchment. Statistical analysis of the catchment data and the measured settling velocity distributions was undertaken. A curve fitting exercise using an S-shaped curve which had the same physical characteristics as the settling velocity distributions was performed. None of these analyses found evidence that the settling velocity distribution of sewage had a significant relationship with the chosen catchment characteristics. The regression equations produced from the statistical analysis cannot be used to assist in the design of separation devices. However, a grading curve envelope was produced, the limits of which were clearly defined for the measured data set. There was no evidence of a relationship between settling velocity grading and the characteristics of the contributing catchment, particularly the catchment area. The present empirical approach to settling tank design cannot be improved upon at present by considering the variation in catchment parameters. This study has provided a basis for future research into the settling velocity measurement and should be of benefit to future workers within this field.
7

North Korea : transport and logistics scenarios and South Korean enterprises' location decisions

Pang, Kelvin Ka Liong January 2012 (has links)
North Korea is one of the world’s last remaining communist countries. Insistence on self-sufficiency has resulted in the stagnation of its economy and collapse of its transport distribution system. This research project examines how various scenarios for North Korea and the implications of South Korean enterprises’ location decisions affect future transport and logistics developments in North Korea. In the foreseeable future, aside from Chinese companies, South Korean investors will probably be the only companies to invest heavily in the North, driven by political and economic motivations. The objectives of this study are four-fold. Firstly, it analyses the political and economic factors affecting North Korea. Secondly, it appraises the present conditions of transport and logistics infrastructure in North Korea. Next, in order to ascertain the implications of business organisations’ decisions to locate in North Korea, it is imperative to determine the probable scenarios surrounding North Korea due to its unique and reclusive nature. Finally, it identifies the factors that will affect potential investors’ location choices. In order to answer the above research question and objectives, a combination of qualitative and quantitative methods was used. In the absence of reliable data from North Korea, an exploratory study was undertaken with eight experts to gain deeper understanding of the issues surrounding North Korea. The insights gathered, together with the comprehensive literature review led to the development of eight sub-research questions. Next, in-depth qualitative interviews were conducted to help develop scenarios for North Korea. Quantitative surveys were concurrently conducted which engaged SMEs and logistics companies. The findings of the research uncovered new insights. Experts think that the status quo scenario is most likely to continue in the near future unless one of the wildcard situations, such as the death of Kim Jong-il occurs. Investors are likely to invest $1-9 million in North Korea, with Nampo and Sinuiju as probable investment locations. Four main factors will influence the location choices of potential South Korean investors including ‘legal’, ‘political economy’, ‘spatial’ and ‘infrastructure’. Road transport was found to be the choice of mode for both experts and investors and China and South Korea would be the mostly like export destinations for North Korean-made products.
8

Enabling sustainable development through logistics: a case of Southern Africa

Fourie, Gerhard 19 June 2019 (has links)
Africa, as a continent, requires rapid development in order to catapult the continent into developed status. As decision-makers on the continent acknowledge this, ambitious development goals have been put in place. This research study analysed whether logistics, and more specifically, transport logistics can contribute to sustainable development on the continent, and if so, in which ways and forms this can be implemented. The qualitative study focused specifically on the SADC region trade block within Africa. The research included a case study of a leader in the transport logistics industry. Interviews with the company’s management committee, as well as the management of its top five clients, have been conducted to form the basis of an explorative study. The findings of this study indicate that logistics can contribute to sustainable development within Africa. Three specific areas of impact have been identified, i.e. the role of logistics as enabler of trade on the continent, its contribution to the combat against climate change and its role in social development. The researcher considers the findings in this paper to be significant for sustainable development in terms of their potential value for use by decision-makers in incorporating logistics into their decision-making. More importantly, the potential significant impact that logistics can have on sustainable development, with the formation of strategic partnerships in achieving these development goals, has been highlighted.
9

Совершенствование системы транспортной логистики промышленного предприятия на основе технологии Blockchain : магистерская диссертация / Improving the transport logistics system of an industrial enterprise based on Blockchain technology

Алексеевский, К. А., Alekseevskiy, K. A. January 2019 (has links)
Деятельность любого промышленного предприятия тесно связано с необходимостью транспортировки грузов. На сегодняшний день процесс доставки грузов осложняется: низкой скоростью логистического цикла; долгим документооборотом и наличием в нём ошибок; сохранностью груза. В ходе научного исследования обоснована возможность применения технологии блокчейн в совершенствовании эффективности транспортно-логистической системы. Однако, универсальный метод внедрения этой технологии на промышленных предприятиях отсутствует. Цель магистерской диссертации заключается в обосновании необходимости внедрения технологии блокчейн в систему транспортной логистики промышленного предприятия. Анализ основывался на изучении научно-периодической литературы, изучении существующих методик исследования и зарубежного опыта внедрения технологии блокчейн в практику её применение на предприятиях. В качестве источников информации использовались нормативно-правовые акты, база публикаций Российского индекса научного цитирования, представленная на ресурсе Elibrary и внутренние документы исследуемого предприятия. Выявленные преимущества технологии блокчейн позволяют обеспечить единое информационное поле для логистической цепи. Использование технологии позволяет построить новую упорядоченную систему передачи информации между участниками логистических цепочек. Данная схема передачи информации может быть осуществлена в рамках авторского подхода, особенностью которого является то, что он включает: модель внедрения технологии блокчейн в систему транспортной логистики предприятия; разработанную автором модель взаимодействия факторов снижения трансформационно-трансакционных затрат; комплекс показателей эффективности процессов транспортной и информационной логистики, а также показатели качества транспортно-логистических систем. По результатам апробации эффективность представлена: через изменение общего показателя эффективности процессов информационной и транспортной логистики; в виде экономии на затратах путём совершенствования процессов системы транспортной логистики на основе технологии блокчейн. Таким образом, экономия на затратах в виде: аренды от простоя вагонов, потери от хранения готовой продукции на складе и вне склада. Таким образом, предложен подход к внедрению технологии блокчейн в системе транспортной логистики предприятия, обеспечивающий единое информационное поле, включающий авторскую модель взаимодействия факторов снижения трансформационно-трансакционных затрат и позволяющий повысить эффективность транспортно-логистический услуг. / The activity of any industrial enterprise is closely connected with the need to transport goods. To date, the process of delivery of goods is complicated by: low speed of the logistics cycle; long document flow and the presence of errors in it; safety of cargo. In the course of the research, the possibility of using blockchain technology to improve the efficiency of the transport and logistics system has been substantiated. However, there is no universal method for introducing this technology in industrial enterprises. The purpose of the master's thesis is to justify the introduction of blockchain technology into the transport logistics system of an industrial enterprise. The analysis was based on the study of scientifically-periodical literature, the study of existing research methods and foreign experience in implementing the blockchain technology into practice its application in enterprises. The sources of information were the regulatory legal acts, the base of publications of the Russian Science Citation Index, presented on the Elibrary resource and internal documents of the enterprise under study. The identified advantages of the blockchain technology allow us to provide a single information field for the logistics chain. The use of technology allows you to build a new orderly system of information transfer between participants in the supply chains. This scheme of information transfer can be carried out within the framework of the author's approach, a feature of which is that it includes: a model for the introduction of blockchain technology into the enterprise's logistics system; a model developed by the author for the interaction of factors reducing transformational transaction costs; a set of indicators of efficiency of transport and information logistics processes, as well as indicators of the quality of transport and logistics systems. According to the results of approbation, the efficiency is presented: through a change in the overall indicator of the efficiency of information and transport logistics processes; in the form of cost savings by improving the processes of the transport logistics system based on blockchain technology. Thus, the cost savings in the form of: rent from idle wagons, losses from storage of finished products in the warehouse and outside the warehouse. Thus, the proposed approach to the introduction of the blockchain technology in the company's transportation logistics system provides a unified information field, including the author’s model of interaction of factors reducing the transformational-transactional costs and improving the efficiency of transport and logistics services.
10

Managing the humanitarian supply chain : a collaborative approach?

Ramsden, Gary P. January 2014 (has links)
Humanitarian disasters are expected to increase 5-fold over the next 50 years. In 2010 a total of 385 separate disasters killed over 297,000 people worldwide, affected more than 217 million others and caused US$ 123.9 billion of economic damages. It is suggested that the scale of resource dedicated to logistics provision in response to disasters accounts for upwards of 80% of the total budget, hence humanitarian logistics both as a practice and a research topic is very much in the spotlight. Consequently, this research addresses what is argued to be the under-representation of humanitarian logistics in the literature and the associated lack of empirical research focussed on the management of the supply chain. Collaborative working has been promoted as a Silver Bullet in many areas of Supply Chain Management and is contended to be a mechanism to prevent organisations optimising solely their own results rather than integrating their goals and activities with others to benefit overall end user value. Collaborative techniques inherent within commercial supply chains have not been observed in the humanitarian relief chain. This study investigates why this is the case, as this lack of collaboration is reported to lead to inefficiency; which at worst results in increased humanitarian suffering and additional loss of life. Hence, the findings reveal ways to advance collaborative working within the humanitarian relief supply chain. Criticism is levelled at the predominance of quantitative methodologies in current research within humanitarian logistics. This study addresses this gap as well as the calls for more cross-organisational case studies within the field, by adopting a multi-case, qualitative approach based on the triangulation of data gathered during a series of in-depth interviews and focus groups across 4 separate humanitarian relief organisations. Data interpretation is through content analysis to identify specific patterns and themes. The research concerns itself with the response immediately following the onset of a disaster. This limited scope helps to address issues surrounding the generalisability of a purely qualitative approach whilst also maintaining control over data volume; however, there are still ample opportunities for significant theoretical and practical contribution. The findings identify specific barriers to collaborative working within the sector; in particular, themes and patterns within management and control, understanding and training, relationships, and military involvement have surfaced. Outcomes also have implications for commercial supply chain managers who are increasingly faced with challenges that no longer obey the traditional rules of forecast driven certainty and predictability, and are therefore, expected to adopt the more event driven, agile and flexible approaches that are already a reality for their humanitarian sector counterparts. The study concludes with the development of a conceptual generic model of the humanitarian supply chain that includes a number of significant issues which, if addressed will improve collaboration and thereby benefit overall efficiency and effectiveness to the general betterment of future relief provision.

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