Commissioning of HVAC systems has potential for significant improvements in occupant satisfaction, comfort and energy consumption, but is very labour-intensive and expensive as practiced at this time. Previous investigators have capitalized on digital control systems' capability of logging and storing data and of interfacing with external computers for open loop control by developing methods of automated fault detection and diagnosis during normal operation. Some investigators have also considered the application of this technique in commissioning. This thesis investigates the possibility of utilizing first principles and empirical models of air-handling unit components to represent correct operation of the unit during commissioning. The models have parameters whose values can be determined from engineering design intent information contained in the construction drawings and other data available at commissioning time. Quasi-dynamic models are developed and tested. The models are tested against design intent information and also against data from a real system operating without known faults. The results show the models agree well with the measured data except for some false positive indications, particularly in the damper and fan models, during transients. A procedure for estimating uncertainty in the instrumentation and the models is developed. The models are also tested against artificial faults and are able to detect all of the faults. Methods of diagnosing the faults are discussed.

Current physiotherapy practice relies on visual observation of the patient for diagnosis and assessment. The assessment process can potentially be automated to improve accuracy and reliability. This thesis proposes a method to recover patient joint angles and automatically extract movement profiles utilizing small and lightweight body-worn sensors. Joint angles are estimated from sensor measurements via the extended Kalman filter (EKF). Constant-acceleration kinematics is employed as the state evolution model. The forward kinematics of the body is utilized as the measurement model. The state and measurement models are used to estimate the position, velocity and acceleration of each joint, updated based on the sensor inputs from inertial measurement units (IMUs). Additional joint limit constraints are imposed to reduce drift, and an automated approach is developed for estimating and adapting the process noise during on-line estimation. Once joint angles are determined, the exercise data is segmented to identify each of the repetitions. This process of identifying when a particular repetition begins and ends allows the physiotherapist to obtain useful metrics such as the number of repetitions performed, or the time required to complete each repetition. A feature-guided hidden Markov model (HMM) based algorithm is developed for performing the segmentation. In a sequence of unlabelled data, motion segment candidates are found by scanning the data for velocity-based features, such as velocity peaks and zero crossings, which match the pre-determined motion templates. These segment potentials are passed into the HMM for template matching. This two-tier approach combines the speed of a velocity feature based approach, which only requires the data to be differentiated, with the accuracy of the more computationally-heavy HMM, allowing for fast and accurate segmentation. The proposed algorithms were verified experimentally on a dataset consisting of 20 healthy subjects performing rehabilitation exercises. The movement data was collected by IMUs strapped onto the hip, thigh and calf. The joint angle estimation system achieves an overall average RMS error of 4.27 cm, when compared against motion capture data. The segmentation algorithm reports 78% accuracy when the template training data comes from the same participant, and 74% for a generic template.

The monitoring of water distribution systems (WDSs) has been a very popular subject of study since the terrorist attacks of September 11, 2001, and the subsequent passing of laws motivating the study of WDS monitoring to provide system protection in the event of a terrorist attack. Inhibiting many WDS monitoring studies to date is the large amount of computational expense required to conduct meaningful studies, especially for larger WDSs that are of most interest. In this study, methods were developed to determine the "importance" of WDS nodes in being considered as locations for sensors used to monitor a WDS in order to make sensor placement optimization more efficient. Single-objective protection goals considered individually in optimization were maximizing detection likelihood, minimizing expected detection time, and minimizing expected contaminated demand volume. A multiobjective protection goal accounting for all three single-objective goals concurrently was also considered; the formulation of the multiobjective optimization problem was intended to minimize tradeoffs among individual protection goals. Sensor placement optimization was carried out with the Iterative Subset Search Method (ISSM) employing genetic algorithms developed in this work; ISSM used nodal importance rankings to search a small subset of nodes for the optimal solution initially then broadened the search incrementally until convergence to a best solution occurred. To demonstrate the effectiveness of the methods developed, sensor placement was performed according to each of the protection goals for three study systems--one small and two large--and a variety of attack conditions. Desirable sensor node solutions that provided for significant protection were found in all cases, and in many cases sensor placement results were comparable to or better than those of other works. Nodal importance narrowed the search for optimal sensor nodes to a relatively small proportion of WDS nodes in most cases.

<p>The Bredasdorp Basin is one of the largest hydrocarbon producing blocks within Southern Africa. The E-M field is situated approximate 50 km west from the FA platform and was brought into commission due to the potential hydrocarbons it may hold. If this field is brought up to full producing capability it will extend the lifespan of the refining station in Mosselbay, situated on the south coast of South Africa, by approximately 8 to 10 years. An unexpected pressure drop within the E-M field caused the suite not to perform optimally and thus further analysis was imminent to assess and alleviate the predicament. The first step within the project was to determine what might have cause the pressure drop and thus we had to go back to cores drilled by Soekor now known as Petroleum South Africa, in the early 1980&rsquo / s.</p> <p><br> <br /> </br>Analyses of the cores exposed a high presence of granulation seams. The granulation seams were mainly subjected within sand units within the cores. This was caused by rolling of sand grains over one another rearranging themselves due to pressure exerted through compaction and faulting, creating seal like fractures within the sand. These fractures caused these sand units to compartmentalize and prohibit flow from one on block to the next. With advance inquiry it was discovered that there was a shale unit situated within the reservoir dividing the reservoir into two main compartments. At this point it was determined to use Petrel which is windows based software for 3D visualization with a user interface based on the Windows Microsoft standards. This is easy as well as user friendly software thus the choice to go with it. The software uses shared earth modeling tool bringing about reservoir disciplines trough common data modelling. This is one of the best modelling applications in the available and it was for this reason that it was chosen to apply within the given aspects of the project A lack of data was available to model the granulation seams but with the data acquired during the core analyses it was possible to model the shale unit and factor in the influences of the granulation seams to asses the extent of compartmentalization. The core revealed a thick shale layer dividing the reservoir within two sections which was not previously noted. This shale layer act as a buffer/barrier restricting flow from the bottom to the top halve of the reservoir. This layer is thickest at the crest of the 10km&sup2 / domal closure and thins toward the confines of the E-M suite. Small incisions, visible within the 3 dimensional models could serve as a guide for possible re-entry points for future drilling. These incisions which were formed through Lowstand and Highstand systems tracts with the rise and fall of the sea level. The Bredasdorp Basin consists mainly of tilting half graben structures that formed through rifting with the break-up of Gondwanaland. The model also revealed that these faults segregate the reservoir further creating bigger compartments. The reservoir is highly compartmentalized which will explain the pressure loss within the E-M suite. The production well was drilled within one of these compartments and when the confining pressure was relieved the pressure dropped and the production decrease. As recommendation, additional wells are required to appraise the E-M structure and determine to what extent the granulation seems has affected fluid flow as well as the degree of sedimentation that could impede fluid flow. There are areas still containing untapped resources thus the recommendation for extra wells.</p>

Interest in the variation of fundamental constants has recently been stimulated by claims that the fine structure constant, α, was smaller in the past. Physicists are investigating whether α is currently varying using a number of methods including atomic clock experiments and quasar absorption spectra. To date atomic clock experiments have not reached the same level of precision as the quasar results but the precision to which transition frequencies are being measured is increasing dramatically and very soon atomic clock experiments based on Earth will be able to rival or surpass the quasar results. In order to relate the change in transition frequencies to a variation of α accurate calculations of relativistic effects in atoms and their dependence upon α are needed. Other effects, such as the small shift of transition frequencies due to blackbody radiation also need to be accounted for. In this thesis we perform accurate calculations of the dependence of transition frequencies in two-valence-electron atoms and ions on a variation of α. The relativistic Hartree-Fock method is used with many-body perturbation theory and configuration interaction methods to calculate transition frequencies. We also consider transitions with an enhanced sensitivity to α variation. In particular, narrow lines that correspond to atomic transitions between close lying, long-lived atomic states of different configurations. The small transition frequency, coupled with differences in the electron structure ensures a strong enhancement of the relative frequency change compared to a possible change in α . We also show that using the modified form of the Dirac Hamiltonian, as suggested by Bekenstein, does not affect the analysis of the quasar data pertaining to a measurement of α variation, nor does it affect atomic clock experiments. Finally we have performed calculations of the size of the frequency shift induced by a static electric field on the clock transition frequencies of the hyperfine splitting in Y b+, Rb, Cs, Ba+, and Hg+. The calculations are used to find the frequency shifts due to blackbody radiation which are needed for accurate frequency measurements and improvements of the limits on variation of α. Our result for Cs [??v/=E2 = -2:26(2) x 10-10Hz/(V/m)2] is in good agreement with early measurements and ab initio calculations. We present arguments against recent claims that the actual value might be smaller. The difference (~ 10%) is due to the continuum spectrum in the sum over intermediate states.

The Intensive Care Unit (ICU) is a unit that manages the most critically ill, complex and unstable patients in the hospital. As a result, the ICU is characterised by a high degree of clinical and organisational unpredictability and uncertainty. In Western discourse, uncertainty is often portrayed as problematic, and as something to be controlled and reduced. This research challenges this discourse by examining the productive relationship between certainty and uncertainty in the work practices of ICU clinicians, and subsequently, how intensive care clinicians utilise uncertainty to construct order in a highly unpredictable work environment. To understand how order can coexist with ICU’s unremitting unpredictability, complexity theory is used to frame this investigation. This research engaged an emergent, interventionist methodology, deploying multiple methods. Using ethnography, video-ethnography, and video-reflexivity, this research relied on clinicians’ participation in the construction and analysis of video data of the ICU clinicians’ work practices. This resulted in clinician-led practice change in the ICU. This research suggests that methods need to be deployed adaptively in order to deal with the complexity of ICU, in addition to the moment-to-moment emergence of events that require the researcher’s own work plans to be revisited. Moreover, in order to gain traction with, and understand highly complex and changeable environments, the researcher needs to also enter and experience uncertainty herself. Using complexity theory as its analytical tool, this research shows an inseparability of uncertainty and certainty in the ICU which is labeled ‘un/certainty’. Three main conclusions emerge from this research. First, un/certainty predominates in intensive care, and due to this, ordering is a process rather than a final state. Un/certainty is at the heart of the adaptive practices that clinicians enact. These adaptive practices are highly interconnected to the changes that the ICU environment may require, and thus produce a dynamic order in the unit. Second, the researcher herself, in order to come to terms with the complexity and un/certainty of the ICU environment must also enter un/certainty in order to gain traction with the ICU environment: unpredictability and complexity cannot be studied from a neat and disengaged distance. Third, the presence of un/certainty in the ICU can be significant and enabling rather than disabling for clinicians in their ongoing pursuit of dynamically ordering practice. The contribution of un/certainty to frontline practice is as a central driver to managing change and complexity. Therefore it should be positively revalued by health services researchers, policy makers and clinicians alike.

Thesis (PhD.(Medical Virology)--Faculty of Health Sciences)-University of Pretoria, 2007. / Includes bibliographical references.

Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2006. / Härtill 4 uppsatser + 1 bil.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.