[pt] Sistemas de Medição de Desempenho (SMD) são amplamente estudados por meio de trabalhos teóricos e práticos. No âmbito de trabalhos práticos, é identificado na literatura uma carência de estudos empíricos que englobem a etapa de implementação. Já os estudos que abordam tal etapa relatam diversas barreiras, o que corrobora com a necessidade de considerar a etapa piloto antes da implementação completa. Essa dissertação de mestrado tem como objetivo: propor um framework conceitual com diretrizes para o redesenho de SMD já existentes comtemplando formalmente uma etapa piloto e realizar o redesenho de um SMD através da utilização de um estudo empírico utilizando o framework conceitual proposto. Além redesenhar o processo e avaliar as barreiras enfrentadas em sua implantação, a dissertação fornece uma avaliação da forma com que a etapa piloto introduzida conseguiu mitigar os riscos mapeados na literatura. / [en] Performance Measurement Systems (PMS) are extensively studied through theoretical and practical work. In the scope of practical work, a lack of empirical studies concerning the implementation stage is identified in the literature. The studies that approach this stage report several barriers, which corroborates with the need to consider the pilot stage before full implementation. This dissertation aims to: propose a conceptual framework with guidelines for the redesign of existing PMS by formally contemplating a pilot phase and carry out the redesign of an PMS through the use of an empirical study using the proposed conceptual framework. In addition to redesigning the process and evaluating the barriers faced in its implementation, the dissertation provides an evaluation of the way in which the pilot stage introduced managed to mitigate the risks mapped in the literature.

Owing to its ability to improve both spectral and energy efficiency of wireless networks, massive multiple-input multiple-output (mMIMO) has become one of the key enablers of the fifth-generation (5G) and beyond communication systems. For successful integration of this promising physical layer technique in the upcoming cellular standards, it is essential to have a comprehensive understanding of its network-level performance. Over the last decade, stochastic geometry has been instrumental in obtaining useful system design insights of wireless networks through accurate and tractable theoretical analysis. Hence, it is only natural to consider modeling and analyzing the mMIMO systems using appropriate statistical constructs from the stochastic geometry literature and gain insights for its future implementation. With this broader objective in mind, we first focus on modeling a cellular mMIMO network that uses fractional pilot reuse to mitigate the sole performance-limiting factor of mMIMO networks, namely, pilot contamination. Leveraging constructs from the stochastic geometry literature, such as Johnson-Mehl cells, we derive analytical expressions for the uplink (UL) signal-to-interference-and-noise ratio (SINR) coverage probability and average spectral efficiency for a random user. From our system analysis, we present a partitioning rule for the number of pilot sequences to be reserved for the cell-center and cell-edge users that improves the average cell-edge user spectral efficiency while achieving similar cell-center user spectral efficiency with respect to unity pilot reuse. In addition, using the analytical approach developed for the cell-center user performance evaluation, we study the performance of a small cell system where user and base station (BS) locations are coupled. The impact of distance-dependent UL power control on the performance of an mMIMO network with unity pilot reuse is analyzed and subsequent system design guidelines are also presented. Next, we focus on the performance analysis of the cell-free mMIMO network, which is a distributed implementation of the mMIMO system that leads to the second and third contributions of this dissertation. Similar to the cellular counterpart, the cell-free systems also suffer from pilot contamination due to the reuse of pilot sequences throughout the network. Inspired by a hardcore point process known as the random sequential adsorption (RSA) process, we develop a new distributed pilot assignment algorithm that mitigates the effect of pilot contamination by ensuring a minimum distance among the co-pilot users. This pilot assignment scheme leads to the construction of a new point process, namely the multilayer RSA process. We study the statistical properties of this point process both in one and two-dimensional spaces by deriving approximate but accurate expressions for the density and pair correlation functions. Leveraging these new results, for a cell-free network with the proposed RSA-based pilot assignment scheme, we present an analytical approach that determines the minimum number of pilots required to schedule a user with probabilistic guarantees. In addition, to benchmark the performance of the RSA-based scheme, we propose two optimization-based centralized pilot allocation schemes using linear programming principles. Through extensive numerical simulations, we validate the efficacy of the distributed and scalable RSA-based pilot assignment scheme compared to the proposed centralized algorithms. Apart from pilot contamination, another impediment to the performance of a cell-free mMIMO is limited fronthaul capacity between the baseband unit and the access points (APs). In our fourth contribution, using appropriate stochastic geometry-based tools, we model and analyze the downlink of such a network for two different implementation scenarios. In the first scenario, we consider a finite network where each AP serves all the users in the network. In the second scenario, we consider an infinite network where each user is served by a few nearby APs in order to limit the load on fronthaul links. From our analyses, we observe that for the finite network, the achievable average system sum-rate is a strictly quasi-concave function of the number of users in the network, which serves as a key guideline for scheduler design for such systems. Further, for the user-centric architecture, we observe that there exists an optimal number of serving APs that maximizes the average user rate. The fifth and final contribution of this dissertation focuses on the potential improvement that is possible by the use of mMIMO in citizen broadband radio service (CBRS) spectrum sharing systems. As a first concrete step, we present comprehensive modeling and analysis of this system with omni-directional transmissions. Our model takes into account the key guidelines by the Federal Communications Commission for co-existence between licensed and unlicensed networks in the 3.5 GHz CBRS frequency band. Leveraging the properties of the Poisson hole process and Matern hardcore point process of type II, a.k.a. ghost RSA process, we analytically characterize the impact of different system parameters on various performance metrics such as medium access probability, coverage probability, and area spectral efficiency. Further, we provide useful system design guidelines for successful co-existence between these networks. Building upon this omni-directional model, we also characterize the performance benefits of using mMIMO in such a spectrum sharing network. / Doctor of Philosophy / The emergence of cloud-based video and audio streaming services, online gaming platforms, instantaneous sharing of multimedia contents (e.g., photos, videos) through social networking platforms, and virtual collaborative workspace/meetings require the cellular communication networks to provide high data-rate as well as reliable and ubiquitous connectivity. These constantly evolving requirements can be met by designing a wireless network that harmoniously exploits the symbiotic co-existence among different types of cutting-edge wireless technologies. One such technology is massive multiple-input multiple-output (mMIMO), whose core idea is to equip the cellular base stations (BSs) with a large number of antennas that can be leveraged through appropriate signal processing algorithms to simultaneously accommodate multiple users with reduced network interference. For successful deployment of mMIMO in the upcoming cellular standards, i.e., fifth-generation (5G) and beyond systems, it is necessary to characterize its performance in a large-scale wireless network taking into account the inherent spatial randomness in the BS and user locations. To achieve this goal, in this dissertation, we propose different statistical methods for the performance analysis of mMIMO networks using tools from stochastic geometry, which is a field of mathematics related to the study of random patterns of points. One of the major deployment issues of mMIMO systems is pilot contamination, which is a form of coherent network interference that degrades user performance. The main reason behind pilot contamination is the reuse of pilot sequences, which are a finite number of known signal waveforms used for channel estimation between a user and its serving BS. Further, the effect of pilot contamination is more severe for the cell-edge users, which are farther from their own BSs. An efficient scheme to mitigate the effect of pilot contamination is fractional pilot reuse (FPR). However, the efficiency of this scheme depends on the pilot partitioning rule that decides the fraction of total pilot sequences that should be used by the cell-edge users. Using appropriate statistical constructs from the stochastic geometry literature, such as Johnson-Mehl cells, we present a partitioning rule for efficient implementation of the FPR scheme in a cellular mMIMO network. Next, we focus on the performance analysis of the cell-free mMIMO network. In contrast to the cellular network, where each user is served by a single BS, in a cell-free network each user can be served by multiple access points (APs), which have less complex hardware compared to a BS. Owing to this cooperative and distributed implementation, there are no cell-edge users. Similar to the cellular counterpart, the cell-free systems also suffer from pilot contamination due to the reuse of pilot sequences throughout the network. Inspired by a hardcore point process known as the random sequential adsorption (RSA) process, we develop a new distributed pilot assignment algorithm that mitigates the effect of pilot contamination by ensuring a minimum distance among the co-pilot users. Further, we show that the performance of this distributed pilot assignment scheme is appreciable compared to different centralized pilot assignment schemes, which are algorithmically more complex and difficult to implement in a network. Moreover, this pilot assignment scheme leads to the construction of a new point process, namely the multilayer RSA process. We derive the statistical properties of this point process both in one and two-dimensional spaces. Further, in a cell-free mMIMO network, the APs are connected to a centralized baseband unit (BBU) that performs the bulk of the signal processing operations through finite capacity links, such as fiber optic cables. Apart from pilot contamination, another implementational issue associated with the cell-free mMIMO systems is the finite capacity of fronthaul links that results in user performance degradation. Using appropriate stochastic geometry-based tools, we model and analyze this network for two different implementation scenarios. In the first scenario, we consider a finite network where each AP serves all the users in the network. In the second scenario, we consider an infinite network where each user is served by a few nearby APs. As a consequence of this user-centric implementation, for each user, the BBU only needs to communicate with fewer APs thereby reducing information load on fronthaul links. From our analyses, we propose key guidelines for the deployment of both types of scenarios. The type of mMIMO systems that are discussed in this work will be operated in the sub-6 GHz frequency range of the electromagnetic spectrum. Owing to the limited availability of spectrum resources, usually, spectrum sharing is encouraged among different cellular operators in such bands. One such example is the citizen broadband radio service (CBRS) spectrum sharing systems proposed by the Federal Communications Commission (FCC). The final contribution of this dissertation focuses on the potential improvement that is possible by the use of mMIMO in the CBRS systems. As our first step, using tools from stochastic geometry, we model and analyze this system with a single antenna at the BSs. In our model, we take into account the key guidelines by the FCC for co-existence between licensed and unlicensed operators. Leveraging properties of the Poisson hole process and hardcore process, we provide useful theoretical expressions for different performance metrics such as medium access probability, coverage probability, and area spectral efficiency. These results are used to obtain system design guidelines for successful co-existence between these networks. We further highlight the potential improvement in the user performance with multiple antennas at the unlicensed BS.

<p dir="ltr">Weather conditions such as thunderstorms, wind shear, snowstorms, turbulence, icing, and fog can create potentially hazardous flying conditions in the National Airspace System (NAS) (FAA, 2021). In general aviation (GA), hazardous weather conditions are most likely to cause accidents with fatalities (FAA, 2013). Therefore, it is critical to communicate weather conditions to pilots and controllers to increase awareness of such conditions, help pilots avoid weather hazards, and improve aviation safety (NTSB, 2017b). Pilot Reports (PIREPs) are one way to communicate pertinent weather conditions encountered by pilots (FAA, 2017a). However, in a hazardous weather situation, communication adds to pilot workload and GA pilots may need to aviate and navigate to another area before feeling safe enough to communicate the weather conditions. The delay in communication may result in PIREPs that are both inaccurate and untimely, potentially misleading other pilots in the area with incorrect weather information (NTSB, 2017a). Therefore, it is crucial to enhance the PIREP submission process to improve the accuracy, timeliness, and usefulness of PIREPs, while simultaneously reducing the need for hands-on communication.</p><p dir="ltr">In this study, a potential method to incrementally improve the performance of an automated spoken-to-coded-PIREP system is explored. This research aims at improving the information extraction model within the spoken-to-coded-PIREP system by using underlying structures and patterns in the pilot spoken phrases. The first part of this research is focused on exploring the structural elements, patterns, and sub-level variability in the Location, Turbulence, and Icing pilot phrases. The second part of the research is focused on developing and demonstrating a structured two-level Named Entity Recognition (NER) model that utilizes the underlying structures within pilot phrases. A structured two-level NER model is designed, developed, tested, and compared with the initial single level NER model in the spoken-to-coded-PIREP system. The model follows a structured approach to extract information at two levels within three PIREP information categories – Location, Turbulence, and Icing. The two-level NER model is trained and tested using a total of 126 PIREPs containing Turbulence and Icing weather conditions. The performance of the structured two-level NER model is compared to the performance of a comparable single level initial NER model using three metrics – precision, recall, and F1-Score. The overall F1-Score of the initial single level NER model was in the range of 68% – 77%, while the two-level NER model was able to achieve an overall F1-Score in the range of 89% – 92%. The two-level NER model was successful in recognizing and labelling specific phrases into broader entity labels such as Location, Turbulence, and Icing, and then processing those phrases to segregate their structural elements such as Distance, Location Name, Turbulence Intensity, and Icing Type. With improvements to the information extraction model, the performance of the overall spoken-to-coded-PIREP system may be increased and the system may be better equipped to handle the variations in pilot phrases and weather situations. Automating the PIREP submission process may reduce the pilot’s hands-on task-requirement in submitting a PIREP during hazardous weather situations, potentially increase the quality and quantity of PIREPs, and share accurate weather-related information in a timely manner, ultimately making GA flying safter.</p>

Titel: Flygfärdighet i företagsledningen? - En kvantitativ studie om ägarstrukturer i svenska börsnoterade bolag   Författare: Maximilian Zuif &amp; Theodor Svedberg   Handledare: Urban Österlund   Bakgrund: I dagens samhälle har fenomenet pilotskolan blivit ett allt hetare samtalsämne inom aktieanalys. Teorier på ämnet menar på att en VD som innehar en betydande andel aktier i det egna bolaget kommer att ha ett större intresse av att bolaget presterar så bra som möjligt. Samtidigt kan tidigare studier anses oense om huruvida ett stort insiderägande hos VD:n har en positiv eller negativ effekt på dess prestation. Ett vanligt nyckeltal som används av investerare för att bedöma hur verksamheten presterar är EBITDA, vilket mäter ett företags vinst före räntor, skatter, ned- och avskrivningar. Under kortare perioder kan det förekomma en stor diskrepans mellan ett bolags aktiepris och hur den underliggande verksamheten presterar. Däremot brukar aktiepriset vara tätt sammanlänkat med bolagets prestation sett över längre tidsperioder.   Syfte: Syftet med studien är att undersöka om det finns något samband mellan VD-ägande och EBITDA-utveckling, samt huruvida det finns något samband mellan EBITDA-utveckling och aktiekurs hos svenska börsnoterade bolag.   Metod: I studien har en kvantitativ metod och en deduktiv forskningsansats använts för att samla in och bearbeta data om bolag listade på Nasdaq OMX Stockholm Mid och Large Cap. Den kvantitativa forskningsmetoden bygger på data kring bolagens ägarstruktur och finansiella prestation för åren 2017 till 2023. Utifrån data har multipla regressionsmodeller skapats för att kunna besvara studiens två forskningsfrågor.   Resultat: Studiens resultat tyder på att det finns ett signifikant positivt samband mellan EBITDA-tillväxt och aktiekursutveckling. Vidare uppvisade den multipla regressionen ett signifikant negativt samband mellan omsättningstillväxt och aktiekursutveckling. Regressionsmodellen som utformades för att undersöka sambandet mellan VD-ägande och EBITDA-utveckling klarade inte Ramsey’s RESET-test, varpå modellen inte kunde anses adekvat. Således hittades i studien inget statistiskt säkerställt samband mellan VD-ägande och EBITDA-utveckling.   Nyckelord: Pilotskolan, VD-ägande, EBITDA, Avkastning, Nasdaq OMX Stockholm Mid Cap, Nasdaq OMX Stockholm Large Cap / Title: Flight skills in the business management? – A quantitative study on ownership structures in Swedish listed firms   Authors: Maximilian Zuif &amp; Theodor Svedberg   Supervisor: Urban Österlund   Background: In today’s society, the pilot school phenomenon has become an increasingly hot topic of conversation in stock analysis. Relevant theories suggests that a CEO who holds a significant part of the shares in his own company will have a greater interest in the company performing as well as possible. At the same time, previous studies can be considered divided on whether a large insider ownership of the CEO has a positive or negative effect on its performance. A common ratio used by investors to assess how the business is performing is EBITDA, which measures a company's earnings before interest, taxes, depreciation and amortization. For shorter periods, there may be a large discrepancy between a company’s share price and how the underlying business is performing. In contrast, the share price is usually closely linked to the company’s performance when looking over longer periods of time.   Aim: The aim of this study is to examine if a relationship exists between CEO stock ownership and growth in EBITDA, as well as whether any relationship exists between growth in EBITDA and development in stock price for Swedish listed firms.   Method: In the study, a quantitative method and a deductive research approach have been used to collect and process data on companies listed on Nasdaq OMX Stockholm Mid and Large Cap. The quantitative research method is based on data about the companies’ ownership structure and financial performance for the years 2017 to 2023. Based on the data, multiple regression models have been created to be able to answer the two research questions in the study.   Results: The results of the study indicate that a significant positive relationship exists between growth in EBITDA and development in stock price. Furthermore, the multiple regression performed in the study showed a significant negative relationship between growth in revenue and stock price development. The regression model designed to examine the relationship between CEO stock ownership and development in EBITDA did not pass Ramsey’s RESET-test, whereupon the model could not be considered adequate. Thus, no statistically proven relationship was found between CEO stock ownership and development in EBITDA.   Keywords: CEO stock ownership, EBITDA, return on investment, Nasdaq OMX Stockholm Mid Cap, Nasdaq OMX Stockholm Large Cap

No / Increasing pressure on health care budgets highlights the need for clinicians to understand the true costs of wound care, in order to be able to defend services against indiscriminate cost cutting. Our aim was to develop and test a straightforward method of measuring treatment costs, which is feasible in routine practice. The method was tested in a prospective study of leg ulcer patients attending three specialist clinics in the UK. A set of ulcer-related health state descriptors were defined on the basis that they represented distinct and clinically relevant descriptions of wound condition ['healed', 'progressing'; 'static''deteriorating; 'severe' (ulcer with serious complications)]. A standardised data-collection instrument was used to record information for all patients attending the clinic during the study period regarding (i) the health state of the ulcer; (ii) treatment received during the clinic visit and (iii) treatment planned between clinic visits. Information on resource use was used to estimate weekly treatment costs by ulcer state. Information was collected at 827 independent weekly observations from the three study centres. Treatment costs increased markedly with ulcer severity: an ulcer which was 'deteriorating' or 'severe' cost between twice and six times as much per week as an ulcer which was progressing normally towards healing. Higher costs were driven primarily by more frequent clinic visits and by the costs of hospitalisation for ulcers with severe complications. This exercise has demonstrated that the proposed methodology is easy to apply, and produces information which is of value in monitoring healing and in potentially reducing treatment costs.

<p>Civil engineering structures must provide an adequate and safe performance during their time of service, and the owners of these structures must have a reliable inspection strategy to ensure time-dependent damage does not become excessive. Visual inspection is the first step in every structural inspection; however, many elements in the majority of structures are difficult to access and require specialized personal and equipment. In an attempt to reduce the risk of the inspector and the cost of additional equipment, the use of Unmanned Aircraft Systems (UAS) has been increasing in the last years. The absence of standards and regulations regarding the use of UAS in inspection of structures has allowed the market to widely advertise Unmanned Aerial Vehicles (UAV) without protocols or qualifications that prove their effectiveness, leaving the owners of the structures to solely rely on claims of the vendors before deciding which technology suits their particular inspection needs. Focusing primarily on bridge inspection, this research aimed to address the lack of performance-based evaluation and standards for UAS, developing a validation criterion to evaluate a given UAS based on a repeatable test that resembles typical conditions in a structure. </p><p><br></p><p>Current applications of UAS in inspection of structures along with its advantages and limitations were studied to determine the current status of UAS technologies. A maximum typical rotor-tip-to-rotor-tip distance of an UAV was determined based on typical UAVs used in bridge inspection, and two main parameters were found to be relevant when flying close to structures: proximity effects in the UAV and availability of visual line of sight. Distances where proximity effects are relevant were determined based on several field inspections and flights close to structures. In addition, the use of supplementary technologies such as Global Positioning System (GPS) and Inertial Measurement Units (IMU) was studied to understand their effect during inspection. </p><p><br></p><p>Following the analysis, the author introduces the idea of a series of obstacles and elements inside an enclosed space that resemble components of bridge structures to be inspected using UAVs, allowing repeatability of the test by controlling outside parameters such as lighting condition, wind, precipitation, temperature, and GPS signal. Using distances based on proximity effects, maximum typical rotor-tip-to-rotor-tip distance, and a gallery of bridges and situations when flying close to bridge structures, a final arrangement of elements is presented as the evaluation chamber. Components inside the evaluation chamber include both “real” steel and concrete specimens as well as those intended to simulate various geometric configurations on which other features are mounted. Pictures of damages of steel and concrete elements have been placed in the internal faces of the obstacles that can be assessed either in real-time flight or in post-processing work. A detailed comparison between the objectives of this research project and the results obtained by the evaluation chamber was performed using visual evaluation and resolution charts for the images obtained, the availability of visual line of sight during the test, and the absence of GPS signal.</p><p><br></p><p>From the comparison and analysis conducted and based on satisfactory flight results as images obtained during flights, the evaluation chamber is concluded to be a repeatable and reliable tool to apply to any UAS prior to inspect bridges and other structures, and the author recommends to refrain from conducting an inspection if the UAS does not comply with the minimum requirements presented in this research work. Additionally, this research provided a clearer understanding of the general phenomenon presented when UAVs approach structures and attempts to fill the gap of knowledge regarding minimum requirements and criterion for the use of UAS technologies in inspection of structures.</p>

隨著Web 2.0社群媒體服務的普及化，越來越多的民眾開始運用網際網路發表自身對於政府治理的需求與看法，大量的民意資訊在網絡的交互連結下，迅速集結成可觀的網路輿情。由於網路輿情具備巨量資料的特性，使得當前各政府部門熟悉的分析方法，似乎產生適用上的困難。因而網路輿情分析的出現，成為當前政府洞察民意的新興工具。更重要的是，如何運用網路輿情分析進一步與政策面產生實質的連結，如探究網路輿情分析當中情緒分析對於政策立場解讀的可能性，對公共管理者而言更為重要。再者，網路輿情分析目前尚缺乏一套檢測方法來驗證其分析結果的信效度。因此，本研究的目的在於，運用網路輿情分析所撈取的輿情資料，比較新聞網站、社群網站、討論區及部落格四類來源在情緒分析與立場分析之差異，最後運用情緒與立場來解讀網路輿情。 研究設計，本文採用次級資料分析法及內容分析法，次級資料來自2014年行政院國發會委託政治大學蕭乃沂教授所主持的「政府應用巨量資料精進公共服務與政策分析之可行性研究」，本文以「自由經濟示範區政策」作為個案分析。研究發現，在立場分析方面，新聞網站及部落格是支持立場的言論最多；而社群網站及討論區則是反對立場的言論最多。情緒分析方面，四類來源皆以負向情緒的言論為主，正向情緒的言論相對少；透過情緒與立場的交叉分析顯示，機器會產生兩類誤判情形，第一類誤判是被機器判讀是正向情緒，但人工判讀為反對立場的言論，以社群網站的來源居多；第二類誤判是被機器判讀是負向情緒，但人工判讀為支持立場的言論，以新聞網站的來源居多。 依此研究發現，本文建議未來實務者在應用網路輿情分析時，不能僅以整體網路輿情分析的結果輕斷，必要時應將不同網路言論來源個別觀察，特別是當負向情緒的輿論出現時，應優先留意社群網站的動向。此外，針對輿情的高峰期也可對照新聞網站的分析結果，了解是否受到特定新聞報導的牽動而引起網民的討論。值得注意的是，針對社群網站中正向情緒的輿論，實務者也不能過於樂觀，因為部份正向情緒的言論可能是帶有網民「拐彎抹角」的反對。 / In the era of Web 2.0, more and more people express their opinions for public governance on the Internet. Massive public opinions are quickly generated. However, it seems difficult to analyze for government because of the feature of big data. Internet public opinion analysis(IPOA) has become new analytical methods for public managers. The purpose of this study is to use IPOA to mine large amounts of policy opinions and conduct sentiment analysis(SA) comparing with political positions analysis(PPA) in the news sites, forums, social networking sites and blogs. Finally, interpreting the network of public opinion by SA and PPA. Secondary data analysis and content analysis are applied. Secondary data collected by the Research, National Development council, the Executive Yuan. A Case Study of Free Economic Pilot Zones Policy is selected. In terms of PPA, the results reveal more supporting political opinions in the news sites and blogs. And more opposing political opinions in the social networking sites and forums. In terms of SA, four types of sources are negative emotions in large part. By cross-analysis, SA and PPA have difference on results. There will be two types of false judgments by SA with machine. One is judged positive emotion by machine, but opposing political opinions by coders, such as social networking sites. The other is judged negative emotion by machine, but supporting political opinions by coders, such as news sites. From this study, author suggests that practitioners should separately make the necessary observation of various networks rather than only determine on overall results as using IPOA. Especially, giving priority to the social networking sites when the opposing political opinions emerge. Moreover, the peak period for opposing political opinions in the social networking sites can be compared with the events in the news sites. It is noteworthy that practitioners should pay attention to the partial positive comments in social network sites with“irony”remarks.

The sample comprised 92 candidates who have completed the Ground School Phase of the trainee pilot training programme. The independent variables are Raven's Advanced Progressive Matrices Test, the Blox Test and the Vienna Determination Test. The dependent variable is the candidates' results after the Ground School Phase of their training. The results indicated that only the Advanced Ravens test and the Vienna Determination test (Phase 3} correlate positively with the Ground School Phase results of the candidates. The current battery emphasises cognitive abilities and psycho-motor functioning and does not cover personality traits of prospective candidates. It is recommended that new instruments are included (to cover the measurement of personality traits), that the sample size should be increased by promoting pilot training among previously disadvantaged students and that the current pilot profile should be updated as a matter of urgency. / Industrial and Organisational Psychology / M.A. (Industrial Psychology)

In the aviation industry, digitally produced and presented flight, navigation, and aircraft information is commonly referred to as glass flight decks. Glass flight decks are driven by computer-based subsystems and have long been a part of military and commercial aviation sectors. Over the past 15 years, the General Aviation (GA) sector of the aviation industry has become a recent beneficiary of the rapid advancement of computer-based glass flight deck (GFD) systems. While providing the GA pilot considerable enhancements in the quality of information about the status and operations of the aircraft, training pilots on the use of glass flight decks is often delivered with traditional methods (e.g. textbooks, PowerPoint presentations, user manuals, and limited computer-based training modules). These training methods have been reported as less than desirable in learning to use the glass flight deck interface. Difficulties in achieving a complete understanding of functional and operational characteristics of the GFD systems, acquiring a full understanding of the interrelationships of the varied subsystems, and handling the wealth of flight information provided have been reported. Documented pilot concerns of poor user experience and satisfaction, and problems with the learning the complex and sophisticated interface of the GFD are additional issues with current pilot training approaches. A case study was executed to explore ways to improve training using GFD systems at a Midwestern aviation university. The researcher investigated if variations in instructional systems design and training methods for learning glass flight deck technology would affect the perceptions and attitudes of pilots of the learnability (an attribute of usability) of the glass flight deck interface. Specifically, this study investigated the effectiveness of scenario-based training (SBT) methods to potentially improve pilot knowledge and understanding of a GFD system, and overall pilot user experience and satisfaction. Participants overwhelmingly reported positive learning experiences from scenario-based GFD systems flight training, noting that learning and knowledge construction were improved over other training received in the past. In contrast, participants rated the usability and learnability of the GFD training systems low, reporting various problems with the systems’ interface, and the learnability (first-time use) of the complex GFD system. However, issues with usability of the GFD training systems did not reduce or change participant attitudes towards learning and mastering GFD systems; to the contrary, all participants requested additional coursework opportunities to train on GFD systems with the scenario-based flight training format.

Approved for public release; distribution is unlimited / OFDM systems have experienced increased attention in recent years and have found applications in a number of diverse areas including telephone-line based ADSL links, digital audio and video broadcasting systems, and wireless local area networks (WLAN). Orthogonal frequency-division multiplexing (OFDM) is a powerful technique for high data-rate transmission over fading channels. However, to deploy OFDM in a WLAN environment, precise frequency synchronization must be maintained and tricky frequency offsets must be handled. In this thesis, various techniques to improve the data throughput of OFDM WLAN are investigated. A simulation tool was developed in Matlab to evaluate the performance of the IEEE 802.11a physical layer. We proposed a rapid time and frequency synchronization algorithm using only the short training sequence of the IEEE 802.11a standard, thus reducing the training overhead to 50%. Particular attention was paid to channel coding, block interleaving and antenna diversity. Computer simulation showed that drastic improvement in error rate performance is achievable when these techniques are deployed. / Lieutenant, Hellenic Navy