Medical imaging is nowadays a vital component of a large number of clinical applications. For comparing images of the same patient (sometimes acquired using different modalities) or for comparing different patients, the images need to be aligned. When images from the same patient or from a collection of patients are acquired using different modalities, their alignment is necessary. Registration is the process of finding the best alignment between a pair or a collection of images. The main topic of this thesis is the conception and the application of intensity-based techniques, both for pairwise and multi-subjects registration. In the context of pairwise registration, we have investigated the use of a stochastic gradient descent technique (SPSA) for optimizing the mutual information metric. For non-rigid registration, the use of volumetric tetrahedral meshes has been implemented as a deformation model in collaboration with A. du Bois d'Aische. The targeted application for our algorithm is the tracking of anatomical changes between pre-operative and intra-operative images in brain, prostate and liver surgery. A second method, equivalent to optical flow but developed for multi-modal images is also described and applied to the problem of atlas to pathological brain registration. In the context of multi-subjects registration, we developed an unbiased atlas generation technique in the Expectation-Maximization framework. At each iteration, the method estimates a reference for the registration problem by performing an average giving more weight to consistent experts (E step). The consistency parameters and the transformation parameters are estimated in the M step. Our atlas generation technique has been applied for aligning 80 brain images segmented in 4 labels (background, gray matter, white matter and ventricles).

The registration of pre-operative volumetric datasets to intra- operative two-dimensional images provides an improved way of verifying patient position and medical instrument loca- tion. In applications from orthopedics to neurosurgery, it has a great value in maintaining up-to-date information about changes due to intervention. We propose a mutual information- based registration algorithm to establish the proper align- ment. For optimization purposes, we compare the perfor- mance of the non-gradient Powell method and two slightly di erent versions of a stochastic gradient ascent strategy: one using a sparsely sampled histogramming approach and the other Parzen windowing to carry out probability density approximation. Our main contribution lies in adopting the stochastic ap- proximation scheme successfully applied in 3D-3D registra- tion problems to the 2D-3D scenario, which obviates the need for the generation of full DRRs at each iteration of pose op- timization. This facilitates a considerable savings in compu- tation expense. We also introduce a new probability density estimator for image intensities via sparse histogramming, de- rive gradient estimates for the density measures required by the maximization procedure and introduce the framework for a multiresolution strategy to the problem. Registration results are presented on uoroscopy and CT datasets of a plastic pelvis and a real skull, and on a high-resolution CT- derived simulated dataset of a real skull, a plastic skull, a plastic pelvis and a plastic lumbar spine segment.

In 2004, with only one fully registered teacher in the early childhood centre where this investigation is set, a question arose as to how five non-registered teachers could be guided through individual programmes of registration advice and guidance. This investigation explores a group approach to early childhood teacher registration, where five registering teachers engaged in written reflections and discussion with their registration tutor, who was also the researcher. The teachers used practitioner inquiry as they explored their own practice and the practice of the team. The researcher used practitioner research to build on the teacher's inquiries. Individual written reflections and group discussions began to highlight differences in the ways teacher's interpreted practice. As part of its communication processes the group regularly compared and categorised individual reflections. These general themes were made public and shared with the group, using a process that this research refers to as the common anonymous voice'. The key findings from this investigation concern the role practitioner action research played in the communication of the group. Discussion and written reflections were shown to provide the group with alternative forms of communication. As tensions and challenges regarding group practice emerged in the discussions, teachers began to rely more on the reflective writing process to articulate their own professional philosophies. Shifts in group dynamics were highlighted as the group moved from the need to agree, through to an acceptance of diversity. Individual teaching beliefs and practices were seen as contributing to the collective process of teaching and learning. The reflexive action research framework developed in this study aligns itself with sociocultural notions of learning and development. Links are made with the professional development of the individual teacher and the collective process of the registration group.

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Inaug.-Diss. -- Göttingen. / Includes bibliographical references (p. [5]-6).

Thesis (M.S.)--University of Iowa, 2009. / Thesis supervisor: Punam K. Saha. Includes bibliographical references (leaves 45-48).

在过去的半个世纪中，戶口（戶籍）制度是影响人们生活机会最重要的社会制度之一，对于能否获得良好的就业机会、医疗、住房，甚至子女教育都是至关重要的决定因素。因此，从农业戶口转为城镇戶口，是一种非常有效的社会上向流动的途径。然而，由于缺乏数据，以往的研究未能评估亲属关系在戶口转换中的作用。依据2008年中国综合社会调查，本文重点考察亲属关系在戶口转换中的作用，将“农转非过程中的亲属关系划分为配偶关系和亲子关系，并考察谁更可能使用这些关系。本研究采用离散时间竞争风险模型，主要探讨家庭出身、教育程度和性别是如何影响不同类型的亲属关系的使用。实证研究结果表明：（1）亲属关系在戶口转换中起到最为重要的角色;（2）父亲的教育和工作单位性质对于采用亲属关系实现戶口转换有很大推动作用，而这主要是通过先让父亲自己得到城镇戶口而实现的;（3）控制了家庭出身后，高中教育对于使用配偶关系有促进作用，主要采用这种关系的是女性，而高职和大学教育则不会影响亲属关系的使用，因为它们本身就是合法的戶口转换渠道;（4）农村妇女更可能通过嫁给一个城镇男性，来获得戶口转换的机会，而大部分的男性则主要通过参军、教育或职业渠道来获得戶口转换;（5）本文还将采用这一性别差异的框架来解决以往戶口转换研究中的一个难题。 / Over the last half century, household registration (hukou) system is perhaps the most important determinants of people’s life chances, access to good jobs, health care, housing and even education for one’s children. Therefore, transforming one’s hukou status from rural to urban is a very effective path to upward social mobility. However, for lack of appropriate data, previous studies have failed to evaluate the role of familial ties in hukou mobility. Drawing on the 2008 Chinese General Social Survey, this paper emphasizes the role of familial ties in hukou mobility, infers from multiple survey questions the important distinction between channels of hukou conversion based on spousal tie and parent-child tie, and examines who are more or less likely to use spousal and parent-child tie. Using the discrete-time competing-risk hazard rate model, this study specifically examines how family origin, educational attainment and gender affect the access to different types of familial-tie-based channels. Empirical findings show that: (1) familial ties play a prominent role in hukou conversion; (2) father’s education and employment at a state work unit facilitate the use of familial ties to achieve hukou conversion, but evidently all due to father’s own attainment of urban hukou in advance; (3) net of the effect of family origin, senior high school education promotes the use of spousal tie, mainly by women, whereas neither vocational school nor college education has significant effects on the use of familial ties, because they are both de jure channels of hukou conversion; (4) rural women are more likely to use marriage to an urban man as a channel for hukou conversion, with signs of status exchange, whereas the majority of men use military, education or employment channels for hukou conversion; (5) the gender-specific framework is then applied to resolve a puzzle of hukou conversion reported in prior literature. / Detailed summary in vernacular field only. / Xiang, Jun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 41-47). / Abstracts also in Chinese.

The Mobile IPv6 (MIPv6) protocol enables mobile nodes (MNs) to remain connected to other correspondent nodes (CNs) while roaming the IPv6 Internet. Home and correspondent registrations are essential parts of the MIPv6 protocol, whereby MNs register their care-of addresses (CoAs) with their home agents (HAs) and with their CNs, respectively. Security provision for home and correspondent registrations is a fundamental part of the MIPv6 protocol and has been an open research issue since the early stages of the protocol.This thesis examines state-of-the-art protocols for securing home and correspondent registrations in MIPv6 networks. The strengths and weaknesses of these protocols are discussed. The investigation of these protocols leads to the proposal of an enhanced home registration protocol and a family of correspondent registration protocols. The Enhanced Home Registration (EHR) protocol extends the basic home registration protocol defined in MIPv6 to support the location authentication of MNs to their HAs. The EHR is based on novel ideas of segmenting the IPv6 address space, using a symmetric CGA-based technique for generating CoAs, and applying concurrent CoAs reachability tests. As a result, EHR is able to reduce the likelihood of a malicious MN being successful in luring an HA to flood a third party with useless packets using MIPv6. In addition, EHR enables HAs to help in correspondent registrations by confirming MNs' CoAs to CNs. Simulation studies of EHR have shown that it only introduces a marginal increase in the registration delay, but a significant increase in the signalling overhead as a cost of supporting the location authentication of MNs.The thesis also proposes a family of correspondent registration protocols. These protocols rely on the assistance of home networks to confirm the MNs' ownership of the claimed HoAs and CoAs. The protocols consist of three phases: a creation phase, an update phase and a deletion phase. Informal and formal protocol analyses have confirmed the protocols' correctness and satisfaction of the required security properties. The protocols have been simulated extensively and the results show that they produce lower registration delay and a reduction in the signalling overhead during update and deletion phases. This is at the cost of a varying increase, depending on the protocol variant, in the registration delay and signalling overhead during the creation phase.

Magister Pharmaceuticae - MPharm / Medicines have to be regulated in an effort to monitor their quality, safety, and efficacy. The process of medicines registration is lengthy, costly, and document-heavy. Many countries have limited expertise and resources at national medicines regulatory authorities (NMRAs) and some countries have adopted unified approaches to medicines registration legislation. Harmonised guidelines and initiatives have been adopted in South Africa and the Southern African Development Community (SADC). However, there are no studies that have identified the effects of these initiatives and guidelines on major stakeholders such as the pharmaceutical industry and regulators.