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In image-guided surgical navigation, instruments tools are tracked by a position sensor and their locations rendered along with the patient's anatomy. Conventional methods require an invasive, time-consuming and potentially uncertain process of intra-operative registration of the images to the patient. In a direct navigation system, such an intra-operative registration is replaced with pre-operative patient-independent calibration in a process that determines the relationship between the coordinate frame of imaging equipment and the coordinate frame of the position sensor. This dissertation presents a method for pre-operatively calibrating a direct navigation system that used an optical position sensor and a mobile gantry CT scanner. A custom bi-local calibration device was designed and manufactured, after which existing navigation software was augmented with components that used the pre-operatively determined transformation to provide image-guided surgical navigation. The resulting system was tested in an image-guided operating suite using plastic bone models. In the validation stage, the inherent error was less than 0.4 mm and the target registration error was approximately 1.6 mm for a ceiling-mounted position sensor and 0.7 mm for a portable position sensor. This accuracy is consistent with the best intra-operative registrations reported in the literature and this calibration method may be useful in future surgical systems. / Thesis (Master, Computing) -- Queen's University, 2013-09-05 12:53:08.994

This study analyses the announcements of European mergers and joint ventures as forms of intra-European direct investment that affect the share prices of U.K. plcs. From a review of the theories of multinational enterprise and foreign direct investment in the context of European economic integration, the study emphasized the importance of the single market and its implications on foreign direct investment. A comparison is made between mergers and joint ventures as forms of foreign direct investment based on their theories and empirical evidences. The effects of the integration on European mergers and joint ventures are then examined by analysing the announcement effects. Using event study methodology, the study investigates the effects of announcements of UK plc acquisitions of European firms and their involvement in European joint ventures on the share prices of UK plcs. Both parametric and non-parametric techniques are used to measure the impact of these announcements in terms of abnormal returns and volatility of returns. The results show positive significant market reaction to the merger announcements on the announcement day for the abnormal return and on the day before the announcement for the volatility. However a significantly negative post announcement cumulative abnormal return is found. A shift of the market reaction after U. K. Is entry into the Exchange Rate Mechanism (ERM) is also found. The market reaction to the joint venture announcements is not significant on the day of announcement. However a significant positive cumulative abnormal return is found a few days prior to the announcement of the joint venture. A positive significant relationship between cumulative market reaction and U.K. Is entry into ERM is also established. Profile analysis of the significant announcements also shows the relevance of certain factors that could explain the market impact of joint ventures.

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