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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.
21

A Spectroscopic Investigation of Some Iron II Complexes

Morris, Monica F. 05 1900 (has links)
<p> A number of complexes FeX2Ln (X = Cl, Br; L = formamide, N-methylformamide, N,N-dimethylformamide, acetamide, benzamide, isobutyramide, urea, N-methylurea, N,N'-dimethylurea, thioacetamide, thiourea, N-methylthiourea, N,N'-dimethylthiourea, benzothiazole, aniline) have been prepared and investigated by means of Mossbauer and infrared spectroscopy and magnetic measurements. It has been possible to distinguish firstly between 4-coordinate and 6-coordinate complexes and secondly between a number of different types of 6-coordinate complexes.</p> / Thesis / Master of Science (MSc)
22

Development of Conjugated Low-coordinate Organophosphorus Materials

WU, Shanshan 12 June 2014 (has links)
No description available.
23

Optimization of composite carriage for a coordinate measurement machine

Lombardi, Marco 11 June 2009 (has links)
The growing need for high quality and reliability of products requires the control of the accuracy of dimensions and shape of product components. Coordinate Measurement Machines (CMM) are now able to measure the dimensions and/or the shape of objects with submicron precision. The desire for high-speed measurement, has stimulated the interest of CMM manufacturers in the use of composite materials for the structure of their machines. Composites are lighter than conventional materials, and are generally less affected by temperature changes. In cooperation with one of the major European CMM manufacturers, the problem of redesigning a steel carriage of a CMM, from composite materials component is considered. A simple strength-of-materials based calculation is used to design a prototype of the carriage, which is built and mounted on the machine to be tested. A NASTRAN finite element model of the composite component is created to analyze more accurately the behavior of the composite structure. Structural optimization is next performed to seek minimum weight and maximum stiffness designs of the structural component. / Master of Science
24

Comparison of the effects of realistic flux surface models on calculations of plasma asymmetries in DIII-D

Collart, Timothy Gerard 07 January 2016 (has links)
Several methods are presented for improving upon the traditional analytic “circular” method for constructing a flux-surface aligned curvilinear coordinate system representation of equilibrium plasma geometry and magnetic fields, and the most accurate Asymmetric Miller method is applied to calculations of poloidal asymmetries in plasma density, velocity, and electric potential. Techniques for developing an orthogonalized coordinate system from a general curvilinear representation of plasma flux surfaces and for representing the poloidal component of the magnetic field in the orthogonalized curvilinear system are developed generally, in order to be applied to four plasma flux-surface models. The formalism for approximating flux surfaces originally presented by Miller is extended to include poloidal asymmetries between the upper and lower plasma hemispheres, and is subsequently shown to be more accurate at fitting the shapes of flux surfaces calculated using EFIT than both the traditional “circular” model and two alternative curvilinear models of comparable complexity based on Fourier expansions of major radius, vertical position, and minor radius. Applying the coordinate system orthogonalization technique to these four models allows for calculations of the poloidal magnetic field which, upon comparison to a calculation of the poloidal field performed in a Cartesian system using the experimentally based EFIT prediction for the Grad-Shafranov equilibrium, demonstrates that the asymmetric “Miller” model is also superior to other methods at representing the poloidal magnetic field. A system of equations developed by representing the poloidal variations of velocity, density, and electric potential using O(1) Fourier expansions in the flux-surface averaged neoclassical plasma continuity and momentum balances is solved using several variations of both the “Miller” and “circular” curvilinear models to set geometric scale factors, illustrating the effects that these improvements in geometric modeling have on tokamak fluid theory calculations.
25

Quantifying Coordinate Uncertainty Fields in Coupled Spatial Measurement systems

Calkins, Joseph Matthew 06 August 2002 (has links)
Spatial coordinate measurement systems play an important role in manufacturing and certification processes. There are many types of coordinate measurement systems including electronic theodolite networks, total station systems, video photogrammetry systems, laser tracking systems, laser scanning systems, and coordinate measuring machines. Each of these systems produces coordinate measurements containing some degree of uncertainty. Often, the results from several different types of measurement systems must be combined in order to provide useful measurement results. When these measurements are combined, the resulting coordinate data set contains uncertainties that are a function of the base data sets and complex interactions between the measurement sets. ISO standards, ANSI standards, and others, require that estimates of uncertainty accompany all measurement data. This research presents methods for quantifying the uncertainty fields associated with coupled spatial measurement systems. The significant new developments and refinements presented in this dissertation are summarized as follows: 1) A geometrical representation of coordinate uncertainty fields. 2) An experimental method for characterizing instrument component uncertainty. 3) Coordinate uncertainty field computation for individual measurements systems. 4) Measurement system combination methods based on the relative uncertainty of each measurement's individual components. 5) Combined uncertainty field computation resulting from to the interdependence of the measurements for coupled measurement systems. 6) Uncertainty statements for measurement analyses such as best-fit geometrical shapes and hidden-point measurement. 7) The implementation of these methods into commercial measurement software. 8) Case studies demonstrating the practical applications of this research. The specific focus of this research is portable measurement systems. It is with these systems that uncertainty field combination issues are most prevalent. The results of this research are, however, general and therefore applicable to any instrument capable of measuring spatial coordinates. / Ph. D.
26

System for Tracking of Surgical Tools and Assessment of Surgical Skills Using Continuously Adaptive Mean Shift Methodology

Manat, Namith N. 01 January 2005 (has links)
A tracking system that serves as a tool for tracking the movement of surgical instruments has been developed. The system tracks color markers on the surgical instruments. The Continuously Adaptive Mean Shift (CAMSHIFT) methodology was employed for tool tracking and a total distance traversed by the surgical instrument of interest was calculated. Two cameras were used to record the motion of the tool and the software developed was used to track the movement of markers on the tools over subsequent frames. The information thus derived from the two views of cameras was used to calculate the three dimensional coordinates of the location of the marker on the instrument and subsequently the distance traversed. MATLAB, which is a commercial software package, was used to implement the tool tracking algorithm and for developing the GUI (Graphic User Interface). Data was collected using Commercial off the shelf (COTS) camera hardware and processing was done on a 2.2 GHz, 512 MB RAM Intel Pentium 4 computer.
27

Proposta de classificação de linhas de base obtidas com dados GPS, à luz de árvore de decisão / Proposal for classification of baselines obtained with GPS data, in light of decision tree

Dorth, Mélodie Kern Sarubo 17 May 2010 (has links)
Ao se efetuar levantamentos utilizando a tecnologia GNSS, o processamento desses dados, bem como uma análise dos fatores oriundos dos processamentos e a correta interpretação dos resultados obtidos, consiste em fator primordial para se definir a qualidade de um levantamento. Contudo, os resultados estatísticos fornecidos pelos softwares comerciais após o processamento e ajustamento dos dados, apesar de garantir maior confiabilidade aos levantamentos, não fornecem a acurácia das coordenadas encontradas, apresentando apenas a sua precisão. Assim, este trabalho tem por objetivo final, fornecer uma tabela onde seja possível, através de uma comparação dos resultados oriundos dos processamentos, classificar a acurácia dos mesmos. Para tanto, foram efetuados os processamentos e ajustamentos de dados inerentes as quatro estações do ano, durante os anos de 2006, 2007 e 2008, e após adequada análise dos mesmos, foi implementada uma Tabela de Acurácia Recomendada, onde os profissionais da área de mensuração poderão, através de uma comparação entre os relatórios de processamento fornecidos e os itens da referida tabela, efetuar a classificação da acurácia dos trabalhos de interesse. / When making surveys using GNSS technology, the processing of these data, as well as an analysis of the factors resulting from the processing and the correct interpretation of results, is to prime factor for defining the quality of a survey. However, the statistics provided by commercial software after processing and adjustment of the data, while ensuring high reliability of surveys, do not provide the accuracy of the coordinates found, showing only its precision. This paper aims to provide a table where possible, by comparing the results from the processing, The classification accuracy of them. To do so, we made adjustments and the processing of data relating the four seasons, during the years 2006, 2007 and 2008, and after proper analysis of the same purpose, a Table of Accuracy Recommended where professionals in the area of measurement may, through a comparison between the reports provided and processing the items of the tariff, to perform the classification accuracy of the work of interest.
28

Coordinate transformation based electromagnetic design and applications

Tang, Wenxuan January 2012 (has links)
The main objective of this thesis is to take one step forward to practical and realisable devices for antenna and microwave engineering, using the technique of discrete coordinate transformation (DCT), which is a practical implementation of the coordinate transformation method. During this thesis, the DCT technique was demonstrated and analysed from the theory, and was proved to provide an all-dielectric approach to design devices under certain conditions. Two schemes were proposed on how to use this technique in a practical design. The first one is to transform an existing device into a flattened profile, meanwhile maintaining its electromagnetic performance. As examples, a flat reflector and a flat lens were created from a parabolic reflector and a convex lens, respectively. The second scheme is to project the propagating paths of an electromagnetic wave, and then generate a distorted space according to the paths by engineering the electromagnetic properties of the media. In this scheme, two examples of application were presented: an undetectable antenna composed of a carpet cloak and a conducting cavity, and a broadband device which can extraordinarily enhance the transmission through a sub-wavelength aperture. Numerical simulations based on the Finite-Difference Time-Domain (FDTD) method were implemented to verify all the designs. Several specific configurations were employed in the modelling in order to simulate the DCT based devices more efficiently and precisely. Performance of these devices was validated and analysed, and the advantages and disadvantages of this technique were investigated. Realisation and fabrication methods i were also studied, and a prototype was designed, fabricated and measured. At the end, as an extension, a multiple discrete coordinate transformation method was proposed and presented. This multiple transformation was proved to effectively relax the limitation of the one-step transformation, and was used to design an all-dielectric thin absorber from a conventional pyramidal one for demonstration.
29

Coordinations de prédicats en mandarin contemporain / Coordinations of predicates in contemporary Mandarin

Lin, Ting-Shiu 15 November 2017 (has links)
Dans ce travail, nous examinons les propriétés syntaxiques et sémantiques des coordonnants de prédicats du mandarin contemporain ainsi que les structures syntaxiques des coordinations qu’ils forment. Nous nous intéressons aux coordinations simples et corrélatives. D’une part, nous découvrons que comme Zhang Ning (2010) l’a avancé les coordinations simples du mandarin ont une structure de type spécifieur-tête-complément : le coordonnant est la tête de la coordination, le conjoint externe le spécifieur et le conjoint interne le complément. Mais d’autre part, nous démontrons que, contrairement à l’affirmation de Zhang Ning (2008), la composition de la structure syntaxique des coordinations corrélatives du mandarin est différente de celles des langues germaniques : les premières sont composées d’une conjonction nulle et de plusieurs particules de focus tandis que les secondes, comme le montrent des travaux antérieurs, sont constituées d’une conjonction prononcée et d’une particule de focus. Au long de notre étude, nous comparons par ailleurs les coordonnants de prédicats du mandarin sur les plans syntaxique et sémantique. Nous remarquons qu’ils diffèrent l’un de l’autre selon au moins l’un des aspects suivants : les catégories syntaxiques des éléments qu’ils peuvent coordonner, les relations sémantiques qu’ils peuvent établir entre leurs conjoints et la possession d’un trait [V] ou d’un trait [-V]. Enfin, nous notons que les prédicats reliés par certains coordonnants doivent, dans la plupart des cas, avoir les mêmes traits aspectuels. Nous expliquons que cette tendance est liée au type de relation sémantique que ces coordonnants établissent entre les prédicats qu’ils relient. / In this dissertation, we study the syntactic and semantic features of several coordinators of predicates in contemporary Mandarin and analyze the syntactic structures of the coordinate constructions formed by these coordinators. We investigate not only simple but also correlative coordinations. We notice that, on the one hand, the Mandarin simple coordination has most likely a head-specifier-complement structure, as Zhang Ning (2010) has proposed: the coordinator is the head, the external conjunct is the specifier and the internal conjunct is the complement. On the other hand, in contrast to Zhang Ning’s (2008) claim, we discover that the correlative coordinations of Mandarin and those of Germanic languages do not have the same syntactic configurations: the former are composed of one silent conjunction and at least two focus-sensitive particles while the latter, as previous research has noted, are made up of one overt conjunction and one focus-sensitive particle. In addition, we find out that the Mandarin coordinators of predicates differ from one another in at least one of the following respects: the syntactic categories of the elements that they can coordinate, the semantic relationships that they may build between their conjuncts and the possession of a [V] feature or a [-V] feature. Last but not least, we notice that the predicates coordinated by some coordinators must, in most of the cases, have identical aspectual features. We argue that this tendency is related to the type of semantic relationship that these coordinators build between their conjuncts.
30

The use of project management mechanisms in software development and their relationship to organisational distance; An emperical investigation

January 2005 (has links)
This thesis describes empirical research into project management of software development. Specifically, the aim of the research is to investigate how project managers monitor, control and coordinate software development tasks and how this is affected by changing environments, in this case increased organizational distance between the project manager and elements of the project team. Differing project environments allow investigation into which project management mechanisms are essential, which are required in specific circumstances and which may be useful but not necessarily essential. To explore how software development projects are monitored, controlled and coordinated, a broad range of literature from software development and other fields such as organization theory, supply chain management and automobile manufacture is examined to establish a consensus of the mechanisms of project monitoring, control and coordination and their classification into groups. To better understand how the different mechanisms may be selected in different circumstances, a range of contingencies is examined to deduce which of these contingencies may significantly affect the project management of software development projects. Outsourced and distributed software development projects are becoming more frequent than in the past with consequent effects on project management practices. Although there has been some research into the ways in which project managers monitor, control and coordinate software development projects, little of it has investigated how the mechanisms employed to do so may be affected by such factors as increasing organizational distance. If more were known about the ways in which changed project environments affected the selection and use of project management mechanisms, better responses to those environmental changes could be devised. This could also identify where tools could be developed to assist project management of outsourced and distributed projects. In this research, the term 'organizational distance' is used to describe the cultural, structural and administrative distance between the project manager and elements of the project team. Since there is limited information available on the concept of organizational distance, a new model is developed that encompasses the dimensions of distance that may be found in outsourced or globally distributed projects. A second model is then developed that relates changes in the factors of organizational distance with preferred choices of project management mechanism via project contingencies. Empirical data were collected by structured interviews with project managers who were currently engaged in software development within Sydney, Australia. The method of collecting the data provided both quantitative and qualitative data that enabled three separate ways to investigate the research questions. The empirical research found that project managers do not rely on a single mechanism to monitor, control or coordinate a software development project but employ multiple mechanisms. While the portfolio of mechanisms for both monitoring and control comprised a relatively narrow selection, the portfolio of coordination mechanisms was more diverse. Project monitoring mechanisms were employed to first detect any project problems then to respond to those problems. This contrasts with monitoring systems designed to provide all the information about both the existence and probable causes of project problems. Project control mechanisms reflected the origin of the control. The constraints imposed on the project by the organization and used by the project manager to direct the project tended to be outcome related, for example budget and schedule. The behaviour of the project team, even across significant organizational distances, was controlled through the use of project plans that determined when different tasks would be performed. Project coordination mechanisms reflected the different types of dependencies between software development activities. The most common was using a project work breakdown structure, expressed in the project schedule, to resolve sequential and pooled resource dependencies. Mutual dependencies tended to be resolved using interactive mechanisms such as co-location, conversations and meetings. The empirical evidence did not find any difference between co-located projects and distributed projects so far as the choice of project management mechanisms were concerned. Distributed and globally outsourced software development projects may encounter many difficulties that a fully co-located project does not, but the response to those difficulties appears to lie with the implementation of project management mechanisms and not their selection.

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