In radiation therapy, interfraction organ motion introduces a level of geometric uncertainty into the planning process. Plans, which are typically based upon a single instance of anatomy, must be robust against daily anatomical variations. For this problem, a model of the magnitude, direction, and likelihood of deformation is useful. In this thesis, principal component analysis (PCA) is used to statistically model the 3D organ motion for 19 prostate cancer patients, each with 8-13 fractional computed tomography (CT) images. Deformable image registration and the resultant displacement vector fields (DVFs) are used to quantify the interfraction systematic and random motion. By applying the PCA technique to the random DVFs, principal modes of random tissue deformation were determined for each patient, and a method for sampling synthetic random DVFs was developed. The PCA model was then extended to describe the principal modes of systematic and random organ motion for the population of patients. A leave-one-out study tested both the systematic and random motion model’s ability to represent PCA training set DVFs. The random and systematic DVF PCA models allowed the reconstruction of these data with absolute mean errors between 0.5-0.9 mm and 1-2 mm, respectively. To the best of the author’s knowledge, this study is the first successful effort to build a fully 3D statistical PCA model of systematic tissue deformation in a population of patients. By sampling synthetic systematic and random errors, organ occupancy maps were created for bony and prostate-centroid patient setup processes. By thresholding these maps, PCA-based planning target volume (PTV) was created and tested against conventional margin recipes (van Herk for bony alignment and 5 mm fixed [3 mm posterior] margin for centroid alignment) in a virtual clinical trial for low-risk prostate cancer. Deformably accumulated delivered dose served as a surrogate for clinical outcome. For the bony landmark setup subtrial, the PCA PTV significantly (p30, D20, and D5 to bladder and D50 to rectum, while increasing rectal D20 and D5. For the centroid-aligned setup, the PCA PTV significantly reduced all bladder DVH metrics and trended to lower rectal toxicity metrics. All PTVs covered the prostate with the prescription dose.

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Process data from wastewater treatment plants are often corrupted by errors. These data provide a basis for operating the plant, therefore effort should be made to improve the data quality. Currently, Stockholm Vatten och Avfall uses a method where they quantitatively verify water flow measurement data by comparing it to water level measurements. In this thesis, an alternative approach based on mass balancing to detect errors was evaluated. The aim was to find, implement and evaluate a mass balance based method to detect and locate errors. The objective was to use this method to corroborate the flow verification method used by Stockholm Vatten och Avfall, and to improve flow data from Bromma Wastewater treatment plant. The chosen method consisted of two major steps, gross error detection and data reconciliation. A case study was performed where the method was tested on both simulated data with known added errors, real process data and finally a case where the suggested method was compared to the flow verification method. The results showed that this method was efficient in detecting a gross error when only one flow measurement was erroneous and that the estimation of the error magnitude was good. However, the suggested method was not useful for corroboration of the flow verification method. With the flow verification method, the flow in one filter basin at the time was examined. The suggested method required the combined flow in all 24 filter basins, which made it difficult to compare the two methods. The method has potential to be valuable for error detection in wastewater treatment plants, and to be used as a live tool to detect gross errors.

一般說來，我們所遇到的線性模式都是 Y＝Xβ＋ι Y 是一N ×１的向量，其元素為應變數的觀測值 X 是一N ×P 的矩陣，其中的元素為已知數 β是一P ×１的向量，其中的元素為母體的參數（parameters） ι是一N ×１的向量，其中的元素為隨機誤差（random errors） 我們可以用幾何求得參數的估計式 β＝（X′X）－X′Y 同理，我們可求得有關β的標準差，建立βi ′s 的信賴區間，及作各種有關的假設 檢定。一旦我們將模式改成 Ｙ＝Ｘα＋ＺU （ii） Y 是一N ×１的向量，其元素為應變數的觀測值 X 是一N ×P 的已知常數矩陣 Z 是N × 的已知常數矩陣 α是P ×１未知的參數向量（固定效應） Ｕ是γ×１的向量，其中包括隨機效應和隨機誤差兩項 因為（ii）式中的隨機向量Ｕ包括隨機效應和隨機誤差兩項，倘若我們把（ii）式中 兩部分予以分解，則（ii）式可以改寫如下： （圖表省略） 本文所討論的是運用已知的原理去估計β和Ｕ，其中將討論如何運用極限的原理去估 計β和Ｕ的向量

Antenna is an indispensable part of a radar or free space communication system. Antenna requires different stringent specifications for different applications. Designed and fabricated for an intended application, antenna or antenna array has to be evaluated for its far-field characteristics in real free space environment which requires setting up of far-field test site. Maintenance of the site to keep the stray reflections levels low, the cost of the real estate are some of the disadvantages. Nearfield measurements are compact and can be used to test the antennas by exploiting the relationship between near-field and far-field. It is shown that the far-field patterns of an antenna can be sufficiently accurately predicted provided the near-field measurements are accurate. Due to limitation in the near-field measurement systems, errors creep in corrupting the nearfield-measured data thus making error in prediction of the far field. All these errors ultimately corrupt the phase and amplitude data. In this thesis, one such near-field measurement facility, the Planar Near Field Measurement facility is discussed. The limitations of the facility and the errors that occur due to their limitations are discussed. Various errors that occur in measurements ultimately corrupt the near-field phase and amplitude. Investigations carried out aim at a detailed study of these phase and amplitude errors and their effect on the far-field patterns of the antenna. Depending on the source of error, the errors are classified as spike, pulse and random errors. The location of occurrence of these types of errors in the measurement plane, their effects on the far-field of the antenna is studied both for phase and amplitude errors. The studies conducted for various phase and amplitude errors show that the near-field phase and amplitude data are more tolerant to random errors as the far-field patterns do not get affected even for low sidelobe cases. The spike errors, though occur as a wedge at a single point in the measurement plane, have more pronounced effect on the far-field patterns. Lower the taper value of the antenna, more pronounced is the error. It is also noticed that the far-field pattern gets affected only in the plane where the error has occurred and has no effect in the orthogonal plane. Pulse type of errors which occur even for a short length in the measurement affect both the principle plane far-field patterns. This study can be used extensively as a tool to determine to the level to which various error such as mechanical, RF etc need to be controlled to make useful and correct pattern predictions on a particular facility. Thereby, the study can be used as a tool to economise the budget of the facility wherein the parameters required for building the facility need not be over specified beyond the requirement. In general, though this is a limited study, it is certainly a trendsetter in this direction.

The diploma thesis consists of a new design of a controlling procedure for a plastic component of a tank. Its theoretical part deals with the potential sources of errors and uncertainties arising from the measuring itself. It also deals with the characteristics of available CMM devices and includes an analysis of the methods assessing the acceptability of the measurement plan. The practical part analyses systematically the current state and proposes a new solution using a program created using a coordinate machine. A comparison of both variants is presented as an output of the thesis.