The difficulty of clustering and the variety of clustering methods suggest the need for a theoretical study of clustering. Using the idea of a standard statistical framework, we propose a new framework for clustering. For a well-defined clustering goal we assume that the data to be clustered come from an underlying distribution and we aim to find a high-density cluster tree. We regard this tree as a parameter of interest for the underlying distribution. However, it is not obvious how to determine a connected subset in a discrete distribution whose support is located in a Euclidean space. Building a cluster tree for such a distribution is an open problem and presents interesting conceptual and computational challenges. We solve this problem using graph-based approaches and further parameterize clustering using the high-density cluster tree and its extension. Motivated by the connection between clustering outcomes and graphs, we propose a graph family framework. This framework plays an important role in our clustering framework. A direct application of the graph family framework is a new cluster-tree distance measure. This distance measure can be written as an inner product or kernel. It makes our clustering framework able to perform statistical assessment of clustering via simulation. Other applications such as a method for integrating partitions into a cluster tree and methods for cluster tree averaging and bagging are also derived from the graph family framework.

Habitat loss is one of the leading causes of species decline across all taxa and conservation practices require information on population trends. The Mescalero Sands ecosystem, New Mexico, USA, is experiencing landscape changes associated with oil and gas development. The dune-dwelling lizard community contains a habitat specialist, Sceloporus arenicolus, that is of particular interest because it has a very limited geographic distribution that is entirely subject to oil and gas development. Distance sampling is widely used to estimate population densities of many vertebrate taxa however assumptions can be difficult to satisfy with certain species or in certain habitats. Researchers must investigate the likelihood that assumptions can be satisfied before implementing any population sampling method. I had two objectives. First to investigate the precision of population densities of dune-dwelling lizards estimated via distance sampling that was coupled with double-observer surveys. Second to compare abundances of dune-dwelling lizards among sites that varied in oil and gas development. I conducted distance line transects and compared those density estimates to densities obtained from total removal plots. I quantified the amount of oil and gas development, habitat quantity and quality and correlated those to lizard abundances to investigate the effects of oil and gas development on lizard populations. I found large differences in density estimates from distance sampling and total removal plots that resulted from violation of distance sampling assumptions. Although distance sampling is a low cost method, it does not produce reliable density estimates for dune-dwelling lizards and is not an appropriate sampling method in this system. I did not find oil and gas development effects on the habitat quantity, quality or on the abundances of lizards. Lizard abundances were most strongly correlated to habitat quantity. Lizard abundances may be influenced by complex interactions between oil and gas development and habitat quantity and quality but controlling for those interactions was beyond the scope of my study. Before and after experiments and long-term studies at multiple sites would be required to more fully address the effects of oil and gas development on lizard populations in the Mescalero Sands.

Abstract Corporate managers are constantly looking for more cost-effective ways to deliver training to their employees. E-learning is less expensive than traditional classroom instruction. In addition, many expenses-booking training facilities, travel costs for employees, plus employee time away from the job- are greatly reduced. Distance learning has existed for a long time. When computers became available, educators were tempted by this new means to deliver education at a distance. Today, what was once an obscure sidebar to education has become big business. This is what people now are talking about e-learning. The value of the computer may seem to be its ability to deliver information anytime and anywhere, but its value in education is potentially much more important. E-learning is fueling efforts to integrate distributed learning systems in organization. The purpose of this study is to examine the some factors that determine intention to adopt e-learning in Kaohsiung Rapid Transit Corporation. The studied system enables online or web-based learning, which has grown in popularity in the new millennium as an innovative and useful enterprising training tool. This paper takes a social, organizational, and technical approach in its investigation to identify the factors that affect intention to adopt e-learning. Regression Analysis was used to assess the relationships in the constructs. The paper presents some findings on e-learning adoption intention determinants in order to giving some suggestions to KRTC for future implementing e-learning training system.

In this thesis, a novel fiber structure with advantages of high coupling efficiency, long working distance and better alignment tolerance has been presented. In this structure, the front-end of the singe-mode fiber (SMF) was spliced a graded-index fiber (GIF) with 50£gm core diameter. A hyperbolic-shaped lens was fabricated in the front-end of GIF. This novel fiber structure can increase the coupling efficiency of SMF effectively by using the wavefront-transfer characteristic of hyperbolic-shaped lens and the focusing characteristic of GIF. According to the simulation results, the optimized length of the GIF was 1160£gm. This novel fiber structure can reach to the coupling efficiency of 77% and working distance of 16£gm when the output power of laser diode was operated at 10mW and the radius curvature of lensed fiber was 12.74£gm. The lateral and longitudinal alignment tolerances of this fiber were 0.8£gm and 1.3£gm, respectively. In comparison with the conventional SMF lens, this novel fiber structure has longer working distance and better fiber alignment tolerance. Therefore, this structure can increase the package yield and reduce the fabrication cost for the application of laser module package.

Abstract For a set D of positive integers, the integral distance graph G(Z, D) is the graph with vertex set Z and edge set { xy : x, y 2 Z and | x − y | 2 D } . An integral distance graph G(Z, D) is called ¡§locally dense¡¨ if the clique size of G(Z, D) is not less to | D | . This paper acterizes locally dense integral distance graphs and determine their chromatic numbers.

Stabilizer codes form a special class of quantum error correcting codes. Nonbinary quantum stabilizer codes are studied in this thesis. A lot of work on binary quantum stabilizer codes has been done. Nonbinary stabilizer codes have received much less attention. Various results on binary stabilizer codes such as various code families and general code constructions are generalized to the nonbinary case in this thesis. The lower bound on the minimum distance of a code is nothing but the minimum distance of the currently best known code. The focus of this research is to improve the lower bounds on this minimum distance. To achieve this goal, various existing quantum codes are studied that have good minimum distance. Some new families of nonbinary stabilizer codes such as quantum BCH codes are constructed. Different ways of constructing new codes from the existing ones are also found. All these constructions together help improve the lower bounds.

Thesis (Ph. D.)--Open University. BLDSC no. DX185079.

Thesis (Ed. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains vii, 134 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 110-119).

Title from title page of PDF (University of Missouri--St. Louis, viewed February 9, 2010). Includes bibliographical references (p. 111-130).

Thesis (Ph. D.)--University of Nebraska--Lincoln, 2002. / Title from title screen. PDF text: [2] leaves abstract; viii, 181 leaves dissertation : ill. Sites viewed on Aug. 30, 2002. Includes bibliographical references (leaves 159-163 of dissertation).