No description available.

A new Ultra-Wideband (UWB) pattern diversity antenna is proposed, designed and investigated in this thesis. The antenna is capable of radiating in directive and omni-directional modes. Three different versions of the design are studied to show the performance for different applications. The first design consists of a single radiating element fed from two sides by coaxial probes over a shaped ground plane. In-phase excitation of the ports produces omni-directional radiation patterns and out-of-phase excitation results in directive radiation in the boresight of the antenna. The shape of the radiator is a disk, which is modified in geometry to improve the isolation of the ports. The antenna shows impedance bandwidth from 6.8 GHz to more than 15 GHz. The second design is a dual-element version of the same antenna to equalize the radiation patterns in the E- and H-planes. The antenna requires four ports and has an impedance bandwidth from 7.4 GHz to more than 15 GHz. A microstrip power divider is then included, in the third design, which in addition to decreasing the number of extra circuits for feeding, decreases the lower frequency to 4.5 GHz, without changing the radiation patterns significantly throughout the bandwidth. A prototype of this antenna was fabricated and measured, and the results are presented. In the fifth chapter, an electromagnetic polarization filter is designed for the single element UWB antenna, to reduce the cross-polarization level. 7 dB reduction in the maximum level of cross-polarization is achieved, throughout the frequency band 8 - 11 GHz. The following chapter is dedicated to the study and performance of the microstrip-fed UWB antenna, when used as a feed for prime-focus reflectors. It is shown that the designed antenna is capable of feeding the reflector with efficiency as high as 75%, and more than 60%, over a wide bandwidth of 5.5 - 9 GHz.

No description available.

Thesis (Ph. D.)--University of Hawaii at Manoa, 1994. / Includes bibliographical references (leaves 181-191). / Microfiche. / xvi, 191 leaves, bound ill. 29 cm

Pattern mining is a knowledge discovery task which is useful for finding interesting data characteristics. Existing mining techniques sometimes suffer from limited performance in challenging situations, such as when finding patterns in high-dimensional datasets. Binary Decision Diagrams and their variants are a compact and efficient graph data structure for representing and manipulating boolean functions and they are potentially attractive for solving many problems in pattern mining. This thesis explores techniques for the use of binary decision diagrams for mining both simple and complex types of patterns. / Firstly, we investigate the use of Binary Decision Diagrams for mining the fundamental types of patterns. These include frequent patterns, also known as frequent itemsets. We introduce a structure called the Weighted Zero-suppressed Binary Decision Diagram and evaluate its use on high dimensional data. This type of Decision Diagram is extremely useful for re-using intermediate patterns during computation. / Secondly, we study the problem of mining patterns in sequential databases. Here, we introduce a new structure called the Sequence Binary Decision Diagram, which can be used for mining frequent subsequences. We show that our technique is competitive with the state of the art and identify situations where it is superior. / Thirdly, we show how Weighted Zero-suppressed Binary Decision Diagrams can be used for discovering new and complex types of patterns. We introduce new types of highly expressive patterns for capturing contrasts, which express disjunctions of attribute values. Moreover, to investigate the usefulness of disjunctive patterns for knowledge discovery, we employ a statistical methodology for testing their significance, and study their use for solving classification problems. Our findings show that classifiers based on significant disjunctive patterns can be more robust than those which are only based on simple patterns. / Finally, we introduce patterns for capturing second-order differences between two groups of classes, which can provide useful insights for human experts. Again, we show how binary decision diagrams can be deployed for efficiently discovering this type of knowledge. / In summary, we demonstrate that Binary Decision Diagrams, are a powerful and scalable tool in pattern mining. We believe their use is very promising for a range of current and future tasks in the data mining context.

Masters Research - Master of Medical Science / Pattern recognition is a non-analytical clinical reasoning process which has been reported in the medical and allied health literature for some time. At a time when clinical problem solving was largely considered to consist of the analytical process of hypothetico-deductive reasoning, pattern recognition was introduced in the literature with observations of greater efficiency and accuracy. The research that followed these apparent opposing models of clinical reasoning resulted in significant growth in the understanding of problem solving in healthcare. On commencing this thesis the knowledge surrounding pattern recognition in physiotherapy was insufficient for its inclusion in educational design. Consequently the aims of the study described in this thesis were to clearly identify pattern recognition using high fidelity case methods and observe its relationship with accuracy and efficiency. The study utilised a single case study with multiple participants. A real clinical case with a diagnosis of high grade lumbar spine spondylolisthesis was simulated using a trained actor. This provided a high fidelity case study method allowing the observation of more realistic problem solving practices as compared with the common low fidelity paper case approach. Two participant groups were included in the study to investigate the common belief that pattern recognition is an experience based reasoning process. The expert group comprised ten titled musculoskeletal physiotherapists with a minimum of ten years overall clinical experience and greater than two years experience following the completion of postgraduate study. The novice group included nine physiotherapists in their first year of clinical practice following completion of an undergraduate degree. Qualitative data collection methods included observation of the participant taking a patient history of the simulated client and a stimulated retrospective recall interview with the participant. The mixed method analysis used in the study provided methodological triangulation of the results and supported the presence of pattern recognition in musculoskeletal physiotherapy. The quantitative research findings indicated that pattern recognition was significantly more likely to produce an accurate diagnostic outcome than analytical reasoning strategies during a physiotherapy history. However its use was not a guarantee of success with only three of the four experts using pattern recognition identifying the correct diagnosis. Although four experts utilised pattern recognition as compared with only one novice, no significant overall differences were found in the use of pattern recognition between the expert and novice participant groups. The findings relating to time data found that expert participants took longer to conduct the client history than novices. Similarly those participants identified using pattern recognition also required more time which seemingly contradicts the view of pattern recognition being an efficient clinical reasoning process. This finding was limited by the incomplete nature of the study which did not include a physical examination or any client management.

Thesis (M. Sc.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references (leaves (184-185). Also available via the World Wide Web.

Thesis (Ph. D.)--Ohio University, March, 2000. / Title from PDF t.p.

Thesis (Ph.D.) - James Cook University, 2003. / Typescript (photocopy) Bibliography: leaves 181-196.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 76-80). Also available via the Internet.