This program of research was aimed at investigating a novel application of computer aided text analysis (CATA). To date, CATA has been used in a wide variety of disciplines, including Psychology, but never in the area of personnel selection. Traditional personnel selection techniques have met with limited success in the prediction of costly training failures for some occupational groups such as pilot and air traffic controller. Accordingly, the overall purpose of this thesis was to assess the validity of linguistic style to select personnel. Several studies were used to examine the structure of language in a personnel selection setting; the relationship between linguistic style and the individual differences dimensions of ability, personality and vocational interests; the validity of linguistic style as a personnel selection tool and the differences in linguistic style across occupational groups. The participants for the studies contained in this thesis consisted of a group of 810 Royal Australian Air Force Pilot, Air Traffic Control and Air Defence Officer trainees. The results partially supported two of the eight hypotheses; the other six hypotheses were supported. The structure of the linguistic style measure was found to be different in this study compared with the structure found in previous research. Linguistic style was found to be unrelated to ability or vocational interests, although some overlap was found between linguistic style and the measure of personality. In terms of personnel selection validity, linguistic style was found to relate to the outcome of training for the occupations of Pilot, Air Traffic Control and Air Defence Officer. Linguistic style also demonstrated incremental validity beyond traditional ability and selection interview measures. The findings are discussed in light of the Five Factor Theory of Personality, and motivational theory and a modified spreading activation network model of semantic memory and knowledge. A general conclusion is drawn that the analysis of linguistic style is a promising new tool in the area of personnel selection.

The objective of an Energy Control Center (ECC) is to ensure secure and economic operation of power system. The challenge to optimize power system operation, while maintaining system security and quality of power supply to customers, is increasing. Growing demand without matching expansion of generation and transmission facilities and more tightly interconnected power systems contribute to the increased complexity of system operation. Rising costs due to inflation and increased environmental concerns has made transmission, as well as generation systems to be operated closure to design limits, with smaller safety margins and hence greater exposure to unsatisfactory operating conditions following a disturbance. Investigations of recent blackouts indicate that the root cause of most of these major power system disturbances is voltage collapse. Information gathered and preliminary analysis, from the most recent blackout incident in North America on 14th August 2003, is pointing the finger on voltage instability due to some unexpected contingency. In this incident, reports indicate that approximately 50 million people were affected interruption from continuous supply for more than 15 hours. Most of the incidents are related to heavily stressed system where large amounts of real and reactive power are transported over long transmission lines while appropriate real and reactive power resources are not available to maintain normal system conditions. Hence, the problem of voltage stability and voltage collapse has become a major concern in power system planning and operation. Reliable operation of large scale electric power networks requires that system voltages and currents stay within design limits. Operation beyond those limits can lead to equipment failures and blackouts. In the last few decades, the problem of reactive power control for improving economy and security of power system operation has received much attention. Generally, the load bus voltages can be maintained within their permissible limits by reallocating reactive power generations in the system. This can be achieved by adjusting transformer taps, generator voltages, and switchable Ar sources. In addition, the system losses can be minimized via redistribution of reactive power in the system. Therefore, the problem of the reactive power dispatch can be optimized to improve the voltage profile and minimize the system losses as well. The Instability in power system could be relieved or at least minimized with the help of most recent developed devices called Flexible AC Transmission System (FACTS) controllers. The use of Flexible AC Transmission System (FACTS) controllers in power transmission system have led to many applications of these controllers not only to improve the stability of the existing power network resources but also provide operating flexibility to the power system. In the past, transmission systems were owned by regulated, vertically integrated utility companies. They have been designed and operated so that conditions in close proximity to security boundaries are not frequently encountered. However, in the new open access environment, operating conditions tend to be much closer to security boundaries, as transmission use is increasing in sudden and unpredictable directions. Transmission unbundling, coupled with other regulatory requirements, has made new transmission facility construction more difficult. In fact, there are numerous technical challenges emerging from the new market structure. There is an acute need for research work in the new market structure, especially in the areas of voltage security, reactive power support and congestion management. In the last few decades more attention was paid to optimal reactive power dispatch. Since the problem of reactive power optimization is non-linear in nature, nonlinear programming methods have been used to solve it. These methods work quite well for small power systems but may develop convergence problems as system size increases. Linear programming techniques with iterative schemes are certainly the most promising tools for solving these types of problems. The thesis presents efficient algorithms with different objectives for reactive power optimization. The approach adopted is an iterative scheme with successive power-flow analysis using decoupled technique, formulation and solution of the linear-programmingproblem with only upper-bound limits on the state variables. Further the thesispresents critical analysis of the three following objectives, Viz., •Minimization of the sum of the squares of the voltage deviations (Vdesired) •Minimization of sum of the squares of the voltage stability L indices (Vstability) •Minimization of real power losses (Ploss) Voltage stability problems normally occur in heavily stressed systems. While the disturbance leading to voltage collapse may be initiated by a variety of causes, the underlying problem is an inherent weakness in the power system. The factors contributing to voltage collapse are the generator reactive power /voltage control limits, load characteristics, characteristics of reactive compensation devices, and the action of the voltage control devices such as transformer On Load Tap Changers (OLTCs). Power system experiences abnormal operating conditions following a disturbance, and subsequently a reduction in the EHV level voltages at load centers will be reflected on the distribution system. The OLTCs of distribution transformers would restore distribution voltages. With each tap change operation, the MW and MVAR loading on the EHV lines would increase, thereby causing great voltage drops in EHV levels and increasing the losses. As a result, with each tap changing operation, the reactive output of generators throughout the system would increase gradually and the generators may hit their reactive power capability limits, causing voltage instability problems. Thus, the operation of certain OLTCs has a significant influence on voltage instability under some operating conditions. These transformers can be made manual to avoid possible voltage instability due to their operation during heavy load conditions. Tap blocking, based on local measurement of high voltage side of load tap changers, is a common practice of power utilities to prevent voltage collapse. The great advantage of this method is that it can be easily implemented, but does not guarantee voltage stability. So a proper approach for identification of critical OLTC s based on voltage stability criteria is essential to guide the operator in ECC, which has been proposed in this thesis. It discusses the effect of OLTCs with different objectives of reactive power dispatch and proposes a technique to identify critical OLTCs based on voltage stability criteria. The fast development of power electronics based on new and powerful semiconductor devices has led to innovative technologies, such as High Voltage DC transmission (HVDC) and Flexible AC Transmission System (FACTS), which can be applied in transmission and distribution systems. The technical and economicalBenefits of these technologies represent an alternative to the application in AC systems. Deregulation in the power industry and opening of the market for delivery of cheaper energy to the customers is creating additional requirements for the operation of power systems. HVDC and FACTS offer major advantages in meeting these requirements. .A method for co-ordinated optimum allocation of reactive power in AC/DC power systems by including FACTS controller UPFC, with an objective of minimization of the sum of the squares of the voltage deviations of all the load buses has been proposed in this thesis. The study results show that under contingency conditions, the presence of FACTS controllers has considerable impact on over all system voltage stability and also on power loss minimization.minimization of the sum of the squares of the voltage deviations of all the load buses has been proposed in this thesis. The study results show that under contingency conditions, the presence of FACTS controllers has considerable impact on over all system voltage stability and also on power loss minimization. As power systems grow in their size and interconnections, their complexity increases. For secure operation and control of power systems under normal and contingency conditions, it is essential to provide solutions in real time to the operator in ECC. For real time control of power systems, the conventional algorithmic software available in ECC are found to be inadequate as they are computationally very intensive and not organized to guide the operator during contingency conditions. Artificial Intelligence (AI) techniques such as, Expert systems, Neural Networks, Fuzzy systems are emerging decision support system tools which give fast, though approximate, but acceptable right solutions in real time as they mostly use symbolic processing with a minimum number of numeric computations. The solution thus obtained can be used as a guide by the operator in ECC for power system control. Optimum real and reactive power dispatch play an important role in the day-to-day operation of power systems. Existing conventional Optimal Power Flow (OPF) methods use all of the controls in solving the optimization problem. The operators can not move so many control devices within a reasonable time. In this context an algorithm using fuzzy-expert approach has been proposed in this thesis to curtail the number of control actions, in order to realize real time objectives in voltage/reactive power control. The technique is formulated using membership functions of linguistic variables such as voltage deviations at all the load buses and the voltage deviation sensitivity to control variables. Voltage deviations and controlling variables are translated into fuzzy set notations to formulate the relation between voltage deviations and controlling ability of controlling devices. Control variables considered are switchable VAR compensators, OLTC transformers and generator excitations. A fuzzy rule based system is formed to select the critical controllers, their movement direction and step size. Results show that the proposed approach is effective for improving voltage security to acceptable levels with fewer numbers of controllers. So, under emergency conditions the operator need not move all the controllers to different settings and the solution obtained is fast with significant speedups. Hence, the proposed method has the potential to be integrated for on-line implementation in energy management systems to achieve the goals of secure power system operation. In a deregulated electricity market, it may not be always possible to dispatch all of the contracted power transactions due to congestion of the transmission corridors. System operators try to manage congestion, which otherwise increases the cost of the electricity and also threatens the system security and stability. An approach for alleviation of network over loads in the day-to-day operation of power systems under deregulated environment is presented in this thesis. The control used for overload alleviation is real power generation rescheduling based on Relative Electrical Distance (RED) concept. The method estimates the relative location of load nodes with respect to the generator nodes. The contribution of each generator for a particular over loaded line is first identified , then based on RED concept the desired proportions of generations for the desired overload relieving is obtained, so that the system will have minimum transmission losses and more stability margins with respect to voltage profiles, bus angles and better transmission tariff. The results obtained reveal that the proposed method is not only effective for overload relieving but also reduces the system power loss and improves the voltage stability margin. The presented concepts are better suited for finding the utilization of resources generation/load and network by various players involved in the day-to-day operation of the system under normal and contingency conditions. This will help in finding the contribution by various players involved in the congestion management and the deviations can be used for proper tariff purposes. Suitable computer programs have been developed based on the algorithms presented in various chapters and thoroughly tested. Studies have been carried out on various equivalent systems of practical real life Indian power networks and also on some standard IEEE systems under simulated conditions. Results obtained on a modified IEEE 30 bus system, IEEE 39 bus New England system and four Indian power networks of EHV 24 bus real life equivalent power network, an equivalent of 36 bus EHV Indian western grid, Uttar Pradesh 96 bus AC/DC system and 205 Bus real life interconnected grid system of Indian southern region are presented for illustration purposes.

Room models, currently used for controller tests, assume the room air to be perfectly mixed. A new room model is developed, assuming non-homogeneous room conditions and distinguishing between different sensor positions. From measurement in real test rooms and detailed CFD simulations, a list of convective phenomena is obtained that has to be considered in the development of a model for a room equipped with different HVAC systems. The zonal modelling approach that divides the room air into several sub-volumes is chosen, since it is able to represent the important convective phenomena imposed on the HVAC system. The convective room model is divided into two parts: a zonal model, representing the air at the occupant zone and a second model, providing the conditions at typical sensor positions. Using this approach, the comfort conditions at the occupant zone can be evaluated as well as the impact of different sensor positions. The model is validated for a test room equipped with different HVAC systems. Sensitivity analysis is carried out on the main parameters of the model. Performance assessment and energy consumption are then compared for different sensor positions in a room equipped with different HVAC systems. The results are also compared with those obtained when a well-mixed model is used. A main conclusion of these tests is, that the differences obtained, when changing the position of the controller's sensor, is a function of the HVAC system and controller type. The differences are generally small in terms of thermal comfort but significant in terms of overall energy consumption. For different HVAC systems the cases are listed, in which the use of a simplified model is not recommended. This PhD has been submitted in accordance to the conditions for attaining both the French and the German degree of a PhD, on a co-national basis, in the frame of a statement of the French government from January 18th, 1994. The research has been carried out in the Automation and Energy Management Group (AGE), Department of Sustainable Development (DDD), at the "Centre Scientifique et Technique du Bâtiment" (CSTB) in Marne la Vallée, France, in collaboration with the "Centre Energétique" (CENERG) at the "Ecole Nationale Supérieure des Mines de Paris" (ENSMP), Paris, France and the Technical University of Dresden (TUD), Germany.

The primary goal of artificial intelligence research is to develop a machine capable of learning to solve disparate real-world tasks autonomously, without relying on specialized problem-specific inputs. This dissertation suggests that such machines are realistic: If No Free Lunch theorems were to apply to all real-world problems, then the world would be utterly unpredictable. In response, the dissertation proposes the information-maximization principle, which claims that the optimal optimization methods make the best use of the information available to them. This principle results in a new algorithm, evolutionary annealing, which is shown to perform well especially in challenging problems with irregular structure. / text

Στην παρούσα διπλωματική εργασία προσομοιώθηκε, μέσω του προγράμματος Matlab και συγκεκριμένα μέσω της εργαλειοθήκης Simulink, ένα υβριδικό μικροδίκτυο το οποίο αποτελούνταν από μια φωτοβολταϊκή διάταξη των 85W, ένα συσσωρευτή ιόντων-λιθίου (Liion battery), δυο DC-DC μετατροπείς και ένα R-L φορτίο. Στην συνέχεια πραγματοποιήθηκαν 4 διαφορετικές τεχνικές ελέγχου σε 2 σημεία, έναν στην πλευρά του φωτοβολταϊκού και έναν στην πλευρά της μπαταρίας. Ο έλεγχος στην πλευρά του φωτοβολταϊκού στόχευε το ρεύμα του φωτοβολταϊκού κάθε χρονική στιγμή να έχει την κατάλληλη τιμή προκειμένου να επιτυγχάνεται η μέγιστη ισχύς μέσω σημείου απόδοσης της μέγιστης ισχύος (MPPT). Ο έλεγχος στην πλευρά της μπαταρίας έχει ως σκοπό την διατήρηση της τάσης του φορτίου στα 100 V.(Vload_reference=100V). Οι έλεγχοι που πραγματοποιήθηκαν ήταν με χρήση PI ελεγκτών, έλεγχοι εκμεταλλευόμενοι την παθητικότητα του Euler-Lagrange συστήματος (PBC), με χρήση ασαφών (fuzzy) ελεγκτών και με χρήση νευρο-ασαφών (neuro-fuzzy) ελεγκτών. / In this diploma thesis a DC hybrid microgrid was simulated by using the program Matlab and specifically the toolbox Simulink. The microgrid consists of a photovoltaic array, a Li-ion battery storage, two DC-DC converters and an R-L load. Four different control methods were then applied to our system in 2 places, one on the photovoltaic array and one on the battery. The one on the photovoltaic array aimed that the PV current would be such that every time the maximum power from the PV would be achieved through a maximum power point tracker. The one on the battery has the purpose of maintaining the load voltage at 100 Volts. The control methods which were implied were PI controllers, passivity based control, fuzzy controllers and neuro-fuzzy controllers.

Οι ηλεκτροµηχανικές συσκευές αποθήκευσης δεδοµένων πολύ µικρής κλίµακας που βασίζονται στη χρήση ανιχνευτών (probes) αποτελούν ανερχόµενες εναλλακτικές επιλογές για τη βελτίωση της πυκνότητας αποθήκευσης, του χρόνου πρόσβασης των δεδοµένων και της απαιτούµενης ισχύος σε σχέση µε τις συµβατικές αποθηκευτικές συσκευές. Μία υλοποίηση µιας τέτοιας συσκευής χρησιµοποιεί θερµοµηχανικές µεθόδους για την αποθήκευση πληροφορίας σε λεπτές µεµβράνες πολυµερών υλικών. Σε αυτή την περίπτωση, η ψηφιακή πληροφορία αποθηκεύεται µε τη µορφή κοιλωµάτων πάνω στο πολυµερές υλικό, οι οποίες δηµιουργούνται από τις άκρες των ανιχνευτών διαµέτρου µερικών nm. Με στόχο την αύξηση του ρυθµού εγγραφής και ανάγνωσης χρησιµοποιούνται διατάξεις από ανιχνευτές που λειτουργούν παράλληλα, µε κάθε ανιχνευτή να εκτελεί λειτουργίες εγγραφής/ανάγνωσης/διαγραφής σε ξεχωριστό αποθηκευτικό πεδίο. Βασικές απαιτήσεις κατά τη λειτουργία τέτοιων συσκευών αποτελούν η εξαιρετικά µεγάλη ακρίβεια και η µικρή καθυστέρηση κατά τη µετακίνηση των ανιχνευτών πάνω από το πολυµερές υλικό. Η παρούσα διατριβή έχει ως αντικείµενο τη µελέτη των διατάξεων κίνησης και τη σχεδίαση πρωτότυπων αρχιτεκτονικών ελέγχου, που οδηγούν στη βελτίωση της απόδοσης των απαιτούµενων, σε συσκευές τέτοιου τύπου, λειτουργιών ελέγχου. Η µετατόπιση του αποθηκευτικού µέσου σε σχέση µε τη διάταξη των ανιχνευτών επιτυγχάνεται µε τη χρησιµοποίηση µικρής κλίµακας scanners, που έχουν δυνατότητες κίνησης σε δύο κατευθύνσεις (x/y). Πληροφορία για τη θέση του microscanner στις δύο κατευθύνσεις παρέχεται από θερµικούς αισθητήρες ανίχνευσης θέσης που κατασκευάζονται µαζί µε τη διάταξη µε τους ανιχνευτές και τοποθετούνται πάνω από το κινητό πλαίσιο. Η πλήρης κατανόηση της συµπεριφοράς των διατάξεων αυτών αποτελεί απαραίτητο στοιχείο για τον αποτελεσµατικό σχεδιασµό και την ανάλυση των συστηµάτων ελέγχου. Στα πλαίσια της διατριβής δηµιουργήθηκε ένα πλήρες µοντέλο της διάταξης του microscanner και των θερµικών αισθητήρων ανίχνευσης θέσης. Σύγκριση της απόκρισης του µοντέλου µε τις πειραµατικές µετρήσεις καταδεικνύει ότι το µοντέλο προσεγγίζει µε εξαιρετική ακρίβεια την απόκριση του συστήµατος. Το σύστηµα ελέγχου περιλαµβάνει, στην αρχή, τη λειτουργία αναζήτησης/ αποκατάστασης, κατά την οποία το σύστηµα εντοπίζει τη θέση όπου απαιτείται να πραγµατοποιηθεί εγγραφή ή ανάγνωση πληροφορίας µε εκκίνηση µία αυθαίρετη θέση του κινητού πλαισίου. Απαίτηση του συστήµατος κατά τη λειτουργία αυτή είναι η ελαχιστοποίηση του χρόνου πρόσβασης των δεδοµένων. Η γρήγορη πρόσβαση στα δεδοµένα αποτελεί µια σηµαντική πρόκληση στις συµβατικές αποθηκευτικές συσκευές. Με το πλεονέκτηµα των ελαφρύτερων µηχανικών µερών, οι υπό µελέτη συσκευές αποθήκευσης βασισµένες στην τεχνολογία MEMS θεωρούνται βασικές υποψήφιες για τη βελτίωση του χρόνου πρόσβασης των δεδοµένων. Οι σχετικές προοπτικές των συσκευών αυτών διερευνώνται αναλυτικά στα πλαίσια της διατριβής. Συγκεκριµένα, αρχικά µελετάται η απόδοση διαφόρων συστηµάτων µε βάση τη θεωρία ελέγχου βέλτιστου χρόνου. Τα αποτελέσµατα της µελέτης δίνουν το θεωρητικά βέλτιστο χρόνο πρόσβασης και την εξάρτησή του από τις παραµέτρους του κάθε συστήµατος. Στη συνέχεια, περιγράφεται η αρχιτεκτονική ελέγχου για τη λειτουργία αναζήτησης και παρουσιάζονται τα αποτελέσµατα που αντλήθηκαν από το περιβάλλον προσοµοίωσης και από την πειραµατική διάταξη. Τα αποτελέσµατα καταδεικνύουν ότι οι χρόνοι πρόσβασης των δεδοµένων που είναι δυνατό να επιτευχθούν µε τις συσκευές αυτές, είναι σηµαντικά µικρότεροι σε σχέση µε τις συµβατικές. Στη συνέχεια, ακολουθεί η λειτουργία παρακολούθησης, όπου η θέση των ανιχνευτών πρέπει να παραµένει στο κέντρο του επιθυµητού καναλιού, κατά τη διάρκεια εγγραφής/ανάγνωσης των δεδοµένων. Η απαίτηση για µεγάλη ακρίβεια στη µετακίνηση πάνω από τη νοητή γραµµή του κέντρου του καναλιού, της µίας ή περισσότερων κεφαλών που χρησιµοποιούνται κατά την εγγραφή/ανάγνωση, είναι σηµαντική για όλους τους τύπους αποθηκευτικών συσκευών. Οι απαιτήσεις για ακρίβεια γίνονται ακόµα πιο µεγάλες και κρίσιµες, στην περίπτωση των υπό µελέτη αποθηκευτικών συσκευών, όπου η ψηφιακή πληροφορία αποθηκεύεται σε µία περιοχή µε µέγεθος µερικών nm. Το σύστηµα ελέγχου, κατά τη λειτουργία αυτή, οφείλει να παρακολουθεί το επιθυµητό σήµα αναφοράς, και ταυτόχρονα να έχει ικανοποιητική απόρριψη των διαταραχών και να επιτυγχάνει την απαιτούµενη ακρίβεια ως προς τον προσδιορισµό της θέσης. Παράλληλα, σηµαντικό παράγοντα βελτιστοποίησης αυτής της λειτουργίας, αποτελεί ο ρυθµός εγγραφής/ανάγνωσης των δεδοµένων. Η πρώτη προσέγγιση για την αρχιτεκτονική ελέγχου, κατά τη λειτουργία αυτή, βασίζεται στην παρεχόµενη από τους θερµικούς αισθητήρες ανίχνευσης, πληροφορία της θέσης του microscanner. Η αρχιτεκτονική βασίζεται στον αλγόριθµο του γραµµικού τετραγωνικού ρυθµιστή (LQG) και η αξιολόγησή της γίνεται µε κριτήρια την ικανότητα παρακολούθησης της εισόδου, την απόρριψη των διαταραχών και την ακρίβεια ως προς τον προσδιορισµό της θέσης. Τα αποτελέσµατα που εξήχθησαν, κατά την υλοποίηση της αρχιτεκτονικής ελέγχου στην πειραµατική διάταξη, αναδεικνύουν ότι η αρχιτεκτονική πληρεί τις απαιτήσεις και η ακρίβεια µερικών nm που επιτυγχάνεται στον προσδιορισµό της θέσης επιτρέπει την αξιόπιστη εγγραφή και κατόπιν ανάγνωση δεδοµένων από την αποθηκευτική συσκευή. Μειονέκτηµα της παραπάνω προσέγγισης αποτελεί ο χαµηλής συχνότητας θόρυβος των θερµικών αισθητήρων, που επηρεάζει τη σωστή λειτουργία του κλειστού συστήµατος σε µεγάλες περιόδους λειτουργίας της συσκευής. Το πρόβληµα αυτό επιλύεται µε µία πρωτότυπη προσέγγιση που αναπτύχθηκε στα πλαίσια της διατριβής και βασίζεται στην πληροφορία, την προερχόµενη από τους θερµικούς αισθητήρες ανίχνευσης θέσης, σε συνδυασµό µε το προερχόµενο από το αποθηκευτικό µέσο σήµα σφάλµατος θέσης. Ο σχεδιασµός του συστήµατος ελέγχου, στην περίπτωση αυτή, εκµεταλλεύεται την εκ των προτέρων γνώση των χαρακτηριστικών θορύβου ως προς τη συχνότητα των δύο αισθητήρων ανίχνευσης θέσης, έτσι ώστε το σύστηµα ελέγχου που προκύπτει να χρησιµοποιεί την πιο αξιόπιστη µέτρηση σε κάθε περιοχή συχνοτήτων. Το πλαίσιο του σθεναρού ελέγχου, H∞, χρησιµοποιείται κατά το σχεδιασµό αυτής της αρχιτεκτονικής ελέγχου, µε διαχωρισµό ως προς τη συχνότητα. Με χρήση αυτής της µεθόδου, το σύστηµα ελέγχου δεν επηρεάζεται από τον χαµηλής συχνότητας θόρυβο των θερµικών αισθητήρων. Τα αποτελέσµατα που εξήχθησαν κατά την υλοποίηση της αρχιτεκτονικής ελέγχου στην πειραµατική διάταξη επιβεβαιώνουν τα παραπάνω. Η µέθοδος αυτή είναι πιο γενική και µπορεί να εφαρµοστεί σε κάθε πρόβληµα ελέγχου, που έχει δύο ή και περισσότερους αισθητήρες µε διαφορετικά χαρακτηριστικά απόδοσης σε διαφορετικές περιοχές συχνοτήτων. / Micro-electro-mechanical-system (MEMS)-based scanning-probe storage devices are emerging as potential ultra-high-density, low-access-time, and low-power alternatives to conventional data storage. One implementation of probe-based storage uses thermomechanical means to store and retrieve information in thin polymer films. Digital information is stored by making indentations on the thin polymer film with the tips of atomic force microscope (AFM) cantilevers, which are a few nanometers in diameter. To increase the data rate, an array of probes is used, in which each probe performs read/write/erase operations over an individual storage field. One of the primary challenges in building such devices is the extreme accuracy and the short latency required in the navigation of the probes over the polymer medium. This dissertation describes the design of novel control architectures and the characterization of their performance. The associated modelling effort, theoretical analysis, simulation work and experimental results are presented. Displacement of the storage medium relative to the array of cantilevers is achieved by using silicon-based micro-scanners with x/y-displacement capabilities. The x/y positional information can be provided by thermal position sensors that are fabricated on the cantilever-array chip and positioned directly above the scan table. A thorough understanding of the dynamics of these parts of the device is essential for effective design and analysis of the control architectures. In this dissertation a complete model of the micro-scanner and the thermal position sensors was developed. Comparison of the model response with the experimental data have shown that the model approximates the system response with an excellent accuracy. In general, the servo system in such a storage device has two functions. First, it locates the target track to which information is to be written or read back from, starting from an arbitrary initial position of the scan table carrying the storage medium. This is achieved by the so-called seek-and-settle procedure. The data access time depends on the duration of this operation, and therefore the minimization of its duration constitutes an important optimization factor. The speed of data access is a significant bottleneck in today’s computing systems. With the advantage of the lighter moving stage MEMS-based storage devices are widely touted to improve access times. In this dissertation these perspectives are examined in detail. Initially the time-optimal control theory has been studied for different system models and their performance has been examined regarding the optimal access time. The results of this study have provided the theoretically optimal access time for each model and its dependence on the system parameters. The control architecture for the seek operation has been designed. The simulation and experimental results show that the possible access times that can be achieved are significantly smaller than the conventional storage devices. The second function of the control system is to maintain the position of the read/write probes on the centre of the target track as they are being scanned along the length of this track during the normal read/write operation. This is achieved by the so-called track-follow procedure. Precise positioning and navigation of the read/write head(s) on the track centerlines is of paramount importance in all types of storage devices. The requirements become more crucial in the devices under study, where in order to achieve reliable storage and retrieval of data, accuracy in the order of a few nanometers in the scanner motion is needed. Therefore, the tracking of the reference signal, the disturbance rejection capabilities and the positioning resolution are considered as performance measures for the control system in this operation. Similarly, the read/write data rate constitutes an important optimization factor for this operation. The first approach of the control architecture for the track-follow procedure uses the position information from the thermal sensors. The control of the position in the x/y directions is realized using two independent feedback loops and each controller is based on the linear quadratic Gaussian regulator (LQG). For the evaluation of the proposed control architecture a detailed analysis has been performed in terms of the tracking performance, the disturbance rejection and the positioning resolution. The proposed architecture has been implemented in the experimental set-up and the analytical results are in agreement with those obtained experimentally. The experimental results show that the accuracy in the motion of the micro-scanner obtained with the proposed control architecture allows reliable storage and retrieval of data in the storage device. The disadvantage of the above control scheme originates from the low frequency noise of the thermal sensors that affects the closed loop performance for long term operation of the device. A novel control architecture was developed that addresses this problem by using medium-derived position information along with the thermal positioning sensor. The objective of this method is, using the a priori knowledge of the noise characteristics of the two sensors, to create a control structure that utilizes the best measurement in different frequency regions. The framework of the H∞ robust control was used for the design of this new frequency separated control architecture. Using this method the control system is not affected from the low frequency noise of the thermal sensors. The experimental results validate the performance of the proposed method. The developed methodology is more general and can be applied to any control problem that has two or more sensors with different performance characteristics in different frequency regions.

Owner companies should consider all elements of Document Management during a project’s life cycle, identify shortcomings and address them successfully to ensure successful completion of projects and ultimately to also ensure legal compliance as stipulated by contractual agreements. Proper governance during the execution of projects involves, amongst others, the establishment of structures and processes, with appropriate checks and balances built into these structures and processes, to enable all stakeholders to be in a position to have access to relevant documentation. Executing projects makes a huge demand on the flow and management of project related documentation through the different phases of these projects. The research, as documented in this dissertation, investigates and evaluates whether Sasol Technology, as the project execution agent for the Sasol Business Units, has efficient governing Document Management processes and procedures in place to support the successful execution of capital projects. Sasol Technology uses a stage gate model, associated with project life cycles, as a systematic approach for the execution of capital projects. Document Management is a new business function that was established in 2008. Not all the functions involved in the life cycle of project execution are fully aligned with the central function managing documentation. There is thus a need for a fully integrated Document Management System, involving all the functions of Sasol which are involved during the different phases of project execution. The literature study analyses existing world best document management and records management practices and procedures and points out that meticulous and strict document and records management practices form the backbone of organisational authentic evidence compliance. The research design method that was chosen to authenticate the research question is an Exploratory Qualitative Approach, combined with a Descriptive Approach. Results are obtained from a combination of three methods. Published and available existing data of how documents are managed in Sasol was gathered and secondary findings are established. Focused and structured interviews were then conducted with experienced team members from the different functions involved in project execution and lastly, e-mail administrated questionnaires were developed and distributed to relevant project team members within Sasol Technology to assess the current system and to determine additional requirements for an enhanced Document Management System, specifically applicable to owner companies in the project execution environment. Whereas the scrutiny of the secondary sources provides a background and the progress iii made with regard to setting requirements for a standardised Document Management System for the execution of projects in the Sasol Technology and some of the other Sasol Business Units, the primary data findings indicate how the project team members perceive the existing Sasol Technology Document Management System to be. Key findings include, that documentation life cycle management is not fully developed and needs to be addressed in the Sasol Technology project execution environment. Furthermore, integration of the documentation management of the various departments, functions and structures in Sasol will enable better and improved management of project documentation. The specific output of this dissertation is the recommendation of an improved Document Management System to allow the different functions within Sasol Technology and some other Sasol Business Units to have access to an integrated system, included in it all relevant documentation requirements during the life cycle of projects. An added deliverable is a framework of requirements to be included in a document management philosophy, not only for Sasol, but also for other owner companies during project execution. / Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2010.

Owner companies should consider all elements of Document Management during a project’s life cycle, identify shortcomings and address them successfully to ensure successful completion of projects and ultimately to also ensure legal compliance as stipulated by contractual agreements. Proper governance during the execution of projects involves, amongst others, the establishment of structures and processes, with appropriate checks and balances built into these structures and processes, to enable all stakeholders to be in a position to have access to relevant documentation. Executing projects makes a huge demand on the flow and management of project related documentation through the different phases of these projects. The research, as documented in this dissertation, investigates and evaluates whether Sasol Technology, as the project execution agent for the Sasol Business Units, has efficient governing Document Management processes and procedures in place to support the successful execution of capital projects. Sasol Technology uses a stage gate model, associated with project life cycles, as a systematic approach for the execution of capital projects. Document Management is a new business function that was established in 2008. Not all the functions involved in the life cycle of project execution are fully aligned with the central function managing documentation. There is thus a need for a fully integrated Document Management System, involving all the functions of Sasol which are involved during the different phases of project execution. The literature study analyses existing world best document management and records management practices and procedures and points out that meticulous and strict document and records management practices form the backbone of organisational authentic evidence compliance. The research design method that was chosen to authenticate the research question is an Exploratory Qualitative Approach, combined with a Descriptive Approach. Results are obtained from a combination of three methods. Published and available existing data of how documents are managed in Sasol was gathered and secondary findings are established. Focused and structured interviews were then conducted with experienced team members from the different functions involved in project execution and lastly, e-mail administrated questionnaires were developed and distributed to relevant project team members within Sasol Technology to assess the current system and to determine additional requirements for an enhanced Document Management System, specifically applicable to owner companies in the project execution environment. Whereas the scrutiny of the secondary sources provides a background and the progress iii made with regard to setting requirements for a standardised Document Management System for the execution of projects in the Sasol Technology and some of the other Sasol Business Units, the primary data findings indicate how the project team members perceive the existing Sasol Technology Document Management System to be. Key findings include, that documentation life cycle management is not fully developed and needs to be addressed in the Sasol Technology project execution environment. Furthermore, integration of the documentation management of the various departments, functions and structures in Sasol will enable better and improved management of project documentation. The specific output of this dissertation is the recommendation of an improved Document Management System to allow the different functions within Sasol Technology and some other Sasol Business Units to have access to an integrated system, included in it all relevant documentation requirements during the life cycle of projects. An added deliverable is a framework of requirements to be included in a document management philosophy, not only for Sasol, but also for other owner companies during project execution. / Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2010.

Ces travaux de thèse consistent en la conception et la réalisation d’une chaîne de tractionintégrée pour véhicule hybride plug-in. L’étude s’oriente vers une solution de convertisseur mutualisé,dans l’objectif de partager la traction et les modes chargeurs de batteries, la structure en NPC à 3niveaux est retenue. Le chargeur monophasé se base une topologie de redresseur à MLI monophaséavec trois bras entrelacés, avec l’utilisation des enroulements du moteur pour le filtrage. En chargeurtriphasé nous adaptons la topologie pour réaliser un montage en double boost triphasé. Pour chaqueconfiguration, les passifs sont dimensionnés pour répondre aux contraintes en courant BF et HF. Lecontrôle adopté se base sur les correcteurs résonants. Enfin, un prototype de 5 kW a été réalisé pourvalider les différents modes de l’application.Dans une seconde partie, nous proposons une solution de chargeur isolé sans étage continu auprimaire à double ponts actifs (DAB). La topologie est modélisée au premier harmonique et unecommande assurant l’absorption sinusoïdale est étudiée. Une configuration isolée triphasée permetl’accès aux puissances plus élevées ainsi que la réduction des ondulations de courant BF en sortie. / This thesis consists on the design and realization of a plug-in hybrid vehicle integrated tractiondrive supply. The work turns to a solution of a mutualized converter, in the objective to imagine asolution which shared drive and battery chargers modes, the three-level NPC topology has beenretained. The single phase charger is based on an interleaved PWM rectifier, and motor windings areused as smoothing inductors. A double-boost PFC configuration is introduced to ensure the threephasecharger. Passives are sized in each configuration in order to take in account the whole currentconstraints (LF and HF). The PFC behavior is based on the resonant controllers. Then, a 5 kWprototype has been realized to validate the different application modes.In a second part, a single-stage isolated charger based on a Dual-Active-Bridge (DAB) isproposed. The topology is modeled to the fundamental and the PFC control law is studied. A threephaseconfiguration is simulated in order to achieve higher charging powers and to reduce batterycurrent low-frequency ripple.

The goal of this project is to develop a system of supervision, communication and control, implemented in a free supervisory software the SCADABR for installed wind farms and/or to be installed in Brazil, from the considerations and recommendations of IEC 61400 - 25. The construction of complete wind farms with full automation, has led entrepreneurs to focus their efforts not only on profit and productivity, but also in: human capital, concerned with the management system, technological mastery and communication at all levels. Information processing with communication, opened borders with new forms of relationship and growing trend in the industrial automation field, which favors different devices to communicate with others in a cooperative way. However, the largest manufacturers of wind generation plants still offer proprietary solutions "black boxes" for the networks field, which results in a variety of protocols of systems, causing the client the full dependence on these suppliers. Aiming interoperability and flexibility of operation, groups of researchers advocate standards of open model, as the solution of networks and protocols for all, leaving customers free. In this struggle, the best-known organization in the field of wind energy is IEC 61400-25, specifically for the monitoring system and free communication among different equipment vendors, nevertheless internal communication of the components of wind power plant is not within the standard. The application range of the standard covers the operation of this kind of wind farm, including wind turbine, meteorological measurement system, electrical system and management system, but does not include the relevant line of the substation feeding and information. Hence, the interaction with the supervisory system SCADABR developed in "open-source" model of free license. It is proposed the application of a multi-platform Java-based, from an application server, like Apache Tomcat the standard choice. Considering the requirements of the present communication model in IEC 61400-25-2 it is defined a model of information for monitoring and control of wind power plants, to this end, part-data simulator MatrikonOPC through customer / OPC DA server interaction (Object Linking and Embedding for Process Control Data Access), with ScadaBR software. / O objetivo da pesquisa é desenvolver um sistema de supervisão, comunicação e controle, implementado em um software de supervisão livre o ScadaBR, para parques eólicos instalados e/ou a serem instalados no Brasil, a partir das considerações e recomendações da norma IEC 61400-25. A construção de parques eólicos completos, com automação total, tem levado os empreendedores a focalizar seus esforços não só no lucro e produtividade, mas também no: capital humano, preocupando-se com o sistema de gestão, domínio tecnológico e comunicação em todos os níveis. O processamento da informação com a comunicação, abriu fronteiras com as novas formas de relacionamento e a crescente tendência na área de automação industrial, favorece que diferentes dispositivos comuniquem-se com outros de uma maneira cooperativa. No entanto, os maiores fabricantes de usinas de geração eólica ainda oferecem soluções proprietárias caixas pretas para as redes de campo, o que resulta numa diversidade de protocolos de sistemas, levando dependência desses fornecedores. Visando a interoperabilidade e flexibilidade de operação, grupos de pesquisadores defendem normas de padrão aberto, como a solução de redes e protocolos para todos, deixando os clientes livres. Nesta luta, a organização mais conhecida na área de energia eólica é a norma IEC 61400-25, especificamente para o sistema de monitoramento e comunicação livre entre diferentes fornecedores de equipamentos, porém a comunicação interna dos componentes da usina de energia eólica não está no âmbito desta norma. A faixa de aplicação da norma abrange parte da operação desse tipo de usina, incluindo turbina de vento, sistema de medição meteorológica, sistema elétrico e sistema de gestão, mas não inclui a linha relevante de alimentação e informação da subestação. Daí a interação com o sistema supervisório ScadaBR, desenvolvido em modelo open-source de licença gratuita. Propõe-se a aplicação de uma multi-plataforma baseada em Java, a partir de um servidor de aplicações, com o Apache Tomcat a escolha padrão. Considerando as exigências do modelo de comunicação presentes na Norma IEC 61400-25-2, define-se um modelo de informação para monitoramento e controle de usinas eólicas, para tal, parte-se do simulador de dados MatrikonOPC, por meio da interação cliente / servidor OPC DA (Object Linkingand Embedding for Process Control Data Access), com o software ScadaBR.