Logic Programming with Solution Preferences: A Declarative Method.

Preference logic programming (PLP) is an extension of constraint logic program­ming for declaratively specifying problems requiring optimization or comparison and selection among alternative solutions to a query. PLP essentially separates the programming of a problem itself from the criteria specification of its solution selection. This thesis presents a declarative method of specifying and executing preference logic programs based on a tabled Prolog system. The method intro­duces a formal predicate mode declaration for designating certain predicates as optimization predicates, and stating the criteria for determining their optimal so­lutions via preference rules. A flexible mode declaration scheme is implemented in a tabled Prolog system, which provides an easy implementation vehicle for programming with preferences. Finally, experimental results and performance analysis demonstrate the effectiveness of the method

Development of a rapid and effective screening method for basal stress tolerance of Petunia x hybrida

High temperature and drought stress are two of the greatest impediments to bedding plant growth and development. The objective of this study was to develop a rapid and effective protocol for screening Petunia x hybrida for basal heat or drought tolerance. A practical growth system for measuring seedling growth, or seedling growth sensitivity test (SGST), was first established. Based on this protocol, radicle growth rate was chosen over hypocotyl growth as the most reliable and accurate measurement for the SGST. Nineteen petunia cultivars from three plant classes (floribunda, grandiflora, or spreading) were previously evaluated, where cultivars within the same plant class and series were grouped as either best or worst for overall landscape performance, and then subjected to the SGST. Seeds were germinated in Petri dishes at 26°C for 4 days and then subjected to 5-h heat shock at a temperature of 40°C or 6 d drought stress at an osmotic potential of -0.8MPa achieved with PEG 6000 to determine heat or drought tolerance, respectively. The results indicated heat or drought stress significantly affected the relative radicle growth rate of seedlings. However, the imposed stress did not affect all cultivars similarly. While ‘Avalanche Lilac’ and ‘Dreams Burgundy Picotee’ had the greatest radicle growth rate, they were considered as more heat susceptible cultivars due to a significant reduction in radicle growth rate under heat stress. ‘Avalanche Lilac’ was also regarded as the most drought sensitive cultivar. The results from this study indicate that the SGST may be used to determine heat or drought tolerance, but further research should be conducted to determine greenhouse and landscape performance under heat or drought stress

Doctor of Philosophy

dissertationThe focus of this dissertation is to explore novel effects in metal nanofilms, particularly, the quantum size effect (QSE) and strain effect, through the methodology of first-principles density functional theory (DFT) calculations. The QSE has already been shown to affect many properties of metal nanofilms, such as surface energy, work function, and even superconducting transition temperature. Based on the extensive DFT calculations that I carried out in the last five years, we further demonstrate that several new properties of metal nanofilms, including edge/surface stress, elastic constants, and adatom-adatom binding energy can also be modulated by QSE to exhibit strong thickness dependence. Specifically, this dissertation includes the following five chapters of topics: ( 1 ) interplay between strain effect and quantum size effect in metal nanofilm; (2 ) quantum manifestation of elastic constants in nanostructures; (3) QSE on adatom-adatom binding energy and island nucleation; (4) quantum manifestations of graphene edge stress and edge instability; (5) bistability of nanoscale islands induced by anisotropic stress. Overall, my dissertation research not only has explained a number of puzzling experimental observations and resolved some existing controversies, but also made some interesting theoretical predictions in novel quantum aspects of thin film growth and nanomechanics. It is my hope that these studies will further our fundamental understanding of QSE and strain effect in metal nanofilms, with broader implications in other low-dimensional nanostructures as well as in potential technological applications of nanostructures

A Comparative Study of Takeover Defences in UK, US and Chinese Law

This thesis explores the issues regarding which regime style would be appropriate for China to adopt in the regulation of takeover defences, given that there are two distinct takeover regulatory systems in the world – that of the UK, and that of the US. China has already adopted a UK-style shareholder-friendly regulatory system. This thesis considers the reasons why China has chosen a shareholder-friendly takeover regulatory system rather than a US-style director-friendly regulatory system. In addition, combining analysis of the character of China’s market and its legal framework, it discusses whether the current regulatory system is appropriate for China or not. Furthermore, it considers specific features of individual takeover defensive tactics and the possibility of their use being legitimised in China. This thesis is relevant because of the likelihood of the freeing up of the Chinese takeover market in the future; as this happens, there will be more and more takeover activity, taking place in China’s market. Thus it is important to provide adequate legislation for market players. Though China adopted the UK’s shareholder regulatory system many years ago, when it first regulated its takeover market, the shareholding structure in China is totally different to the UK’s, and so it is important to discuss whether this regulatory system is still relevant for China or whether there should be a change to a regulatory system more like that of the US. As China issued the Administrative Measures of Preferred Shares Experimental Units in 2014, and the new leadership in China has continued China’s economic reform over recent years, it i could be said that China’s listed companies have become more attractive to investors and there could be more hostile raiders entering the market. Hence there is a need to consider whether China’s delegation of decision-making powers to the shareholders regarding defence against hostile raiders is appropriate. It is also important to establish which takeover defence measures might appropriately be legalised and which would be inappropriate for China. Chapter 1 introduces background information about the trend of mergers and acquisitions and hostile takeovers, China’s state-owned enterprises and briefly consider takeover defensive measures. Following this, it discusses shareholding structures, and problems in China’s market in comparison with the UK and US. Chapter 2 outlines both the UK’s and US’s distinctive takeover regulatory systems and evaluates their pros and cons, as well as the reasons why certain regulatory systems are suitable for each market. Chapter 3 explores the differences between China’s ownership structure, market, and legal framework, and those of the UK and US. It also summarises the weaknesses of the Chinese system(s) in seeking to transplant a western-style set of takeover regulations into China’s market. Primarily, these are that (a) China does not provide sufficient legislation relating to takeover defence measures and (b) Chinese market players and legal advisors do not have adequate experience of takeover defence measures. ii Chapter 4 discusses takeover defence measures related to stock trading – share repurchase, the ‘pac-man’ defence, the use of white knights and ESOP. The chapter concludes that the first two tactics may be too risky for target companies such that their adoption should be prohibited in China while the latter two tactics may be helpful and could be widely used by China’s listed companies. Chapter 5 considers takeover defence measures related to management, such as poison pills, shark repellents, the scorched earth policy, dual class recapitalization and three kinds of parachutes. Except for the scorched earth policy, which could be harmful to the long-term interests of target companies, the other tactics may work well in China’s market and help Chinese companies secure controlling power or raise the share premium. Chapter 6 looks into defensive measures relating to litigation, raising anti-trust issues with relevant authorities, inadequate information provision by bidders and other crimes. It summarizes how measures relating to litigation could help delay the hostile takeover process, but could also terminate it, even if the target company is only seeking a greater share premium. This process could also involve government intervention, and its effectiveness cannot be guaranteed. Even if this group of measures are the most frequently used tactics by target companies, this thesis does not recommend it over other options. Chapter 7 analyses and compares the legislative systems of the US and UK and concludes that the UK’s system is better for contemporary China. However, there is iii still the potential for China to legalise certain takeover defensive measures in the future as China’s market is continually being reformed. Chapter 8 concludes the thesis in proposing that China is justified in adopting the UK’s shareholder-friendly regulatory system. This is partly based on consideration of promoting takeover activities, and the existence of China’s SOEs, which may be reasons to prohibit certain defensive measures in China’s market. As the reform of China’s market continues, moderate defensive tactics like the white knight, parachute system and poison pill could work well. However, the decision-making power should remain in the hands of shareholders and the government should provide sufficient supervision over the market whilst following the principle of protecting shareholders’ interests. The importance of the thesis, and its contribution to existing knowledge, is the research for it has found that most other researchers are focused on the mandatory bid rule – adopted from the UK – in China, but that hardly any systematic research is being undertaken into defensive measures. Thus, this thesis fills a gap in the current literature on the takeover regulations area for China. It also discusses most of the major takeover defensive tactics, analysing in which markets certain defensive tactics work, and whether they would be appropriate for China. Newly-released regulations show the intention of Chinese legislators to turn to a more US style – which will make certain takeover defence measures possible in China, such as the poison pill; whether these are suitable for the Chinese market is debatable. In addition, it is found that iv Chinese companies, especially high-tech companies, quite frequently use several defensive measures when they list on the US market, and the function of these tactics in securing control over the target company can be seen. Thus, research into how to regulate those defensive measures and what problems might arise with their use in China is important for regulators, and will make this thesis meaningful in China

A Customer Programmable Microfluidic System

Microfluidics is both a science and a technology offering great and perhaps even revolutionary capabilities to impact the society in the future. However, due to the scaling effects there are unknown phenomena and technology barriers about fluidics in microchannel, material properties in microscale and interactions with fluids are still missing. A systematic investigation has been performed aiming to develop A Customer Programmable Microfluidic System . This innovative Polydimethylsiloxane (PDMS)-based microfluidic system provides a bio-compatible platform for bio-analysis systems such as Lab-on-a-chip, micro-total-analysis system and biosensors as well as the applications such as micromirrors. The system consists of an array of microfluidic devices and each device containing a multilayer microvalve. The microvalve uses a thermal pneumatic actuation method to switch and/or control the fluid flow in the integrated microchannels. It provides a means to isolate samples of interest and channel them from one location of the system to another based on needs of realizing the customers\u27 desired functions. Along with the fluid flow control properties, the system was developed and tested as an array of micromirrors. An aluminum layer is embedded into the PDMS membrane. The metal was patterned as a network to increase the reflectivity of the membrane, which inherits the deformation of the membrane as a mirror. The deformable mirror is a key element in the adaptive optics. The proposed system utilizes the extraordinary flexibility of PDMS and the addressable control to manipulate the phase of a propagating optical wave front, which in turn can increase the performance of the adaptive optics. Polydimethylsiloxane (PDMS) has been widely used in microfabrication for microfluidic systems. However, few attentions were paid in the past to mechanical properties of PDMS. Importantly there is no report on influences of microfabrication processes which normally involve chemical reactors and biologically reaction processes. A comprehensive study was made in this work to study fundamental issues such as scaling law effects on PDMS properties, chemical emersion and temperature effects on mechanical properties of PDMS, PDMS compositions and resultant properties, as well as bonding strength, etc. Results achieved from this work will provide foundation of future developments of microfluidics utilizing PDMS