CAPES / Neste trabalho é realizada a análise da eficiência energética para algumas redes sem fio de curto alcance, como as redes de sensores sem fio, e algumas redes sem fio de longo alcance, como as redes de telefonia celular. Na análise de sensores sem fio são empregados esquemas de transmissão cooperativos e não-cooperativos, considerando que um canal de retorno pode estar disponível ou não. Para a análise de redes celulares, considera-se o uso de técnicas de transmissão com múltiplas antenas, modelos realistas de consumo de potência, além de um modelo de custos para a análise financeira de diferentes projetos de redes. São consideradas nas análises do desempenho de eficiência energética restrições como uma probabilidade de outage e uma vazão fim-a-fim alvos ao sistema. Os resultados obtidos indicam os esquemas de transmissão e projetos de redes mais eficientes para diferentes condições. Além disso, o planejamento dos direcionamentos para os trabalhos futuros é apresentado. / The energy efficiency analysis for some short-range wireless networks, such as wireless sensor networks, and for some long-range wireless networks, such as cellular networks is performed in this work. For the wireless sensor networks analysis, non-cooperative and cooperative transmission schemes (considering that a return channel is available or not) are employed. Multiple antennas transmission schemes, realistic power consumption models, and a cost model for different system designs are considered for the cellular networks analysis. We consider that the system is under constraints such as a target end-to-end outage probability and a target end-to-throughput. The results show the most efficient transmission schemes and network designs under different system conditions. The future works plans are also detailed.

The Ericsson R380 is a so-called smartphone, combining an advanced mobile phone with a Personal Digital Assistant (PDA). To evaluate the usability of the Ericsson R380 and benchmark it against the Nokia 9110 Communicator and the Motorola A6188 Accompli, a repeated measurements experiment was performed. 18 subjects (10 men and 8 women) with no previous experience of any of the interfaces participated. Half of the subjects had extensive experience from using Ericsson mobile phones and half of the subjects had extensive experience from using Nokia mobile phones. A set of 9 tasks to be solved on each interface was presented to the subjects. The order in which the subjects used the interfaces was balanced with a Latin square design while the tasks were presented in consecutive order and were identical for all interfaces. Level of completeness, completion time and number of actions were assessed for each task and interface. Subjects also rated the perceived usability and aesthetics of the interfaces. Overall, subjects were most successful using the Motorola A6188 Accompli, using fewer keystrokes and less time as well as needing fewer hints compared to the Ericsson R380 and Nokia 9110 Communicator. However, the Ericsson R380 was rated significantly higher than the other interfaces on perceived usability. Previous experience with Ericsson or Nokia mobile phones did not have a major impact on how well subjects succeeded with using the interfaces in the test. Certain mistakes made by each group of subjects could be explained in terms of mental models, Einstellung effects and the use of so- called Function-Object interaction style where Object-Function interaction was appropriate. Contrary to earlier findings, aesthetics and perceived usability did not correspond to a great extent. Finally, the results are discussed and some suggestions for improvements are put forward.

Second economy people in developing countries are people living in communities that are underserved in terms of basic amenities and social services. Due to literacy challenges and user accessibility problems in rural communities, it is often difficult to design user interfaces that conform to the capabilities and cultural experiences of low-literacy rural community users. Rural community users are technologically illiterate and lack the knowledge of the potential of information and communication technologies. In order to embrace new technology, users will need to perceive the user interface and application as useful and easy to interact with. This requires proper understanding of the users and their socio-cultural environment. This will enable the interfaces and interactions to conform to their behaviours, motivations as well as cultural experiences and preferences and thus enhance usability and user experience. Mobile phones have the potential to increase access to information and provide a platform for economic development in rural communities. Rural communities have economic potential in terms of agriculture and micro-enterprises. Information technology can be used to enhance socio-economic activities and improve rural livelihood. We conducted a study to design user interfaces for a mobile commerce application for micro-entrepreneurs in a rural community in South Africa. The aim of the study was to design mobile interfaces and interaction techniques that are easy to use and meet the cultural preferences and experiences of users who have little to no previous experience of mobile commerce technology. And also to explore the potentials of information technologies rural community users, and bring mobile added value services to rural micro-entrepreneurs. We applied a user-centred design approach in Dwesa community and used qualitative and quantitative research methods to collect data for the design of the user interfaces (graphic user interface and voice user interface) and mobile commerce application. We identified and used several interface elements to design and finally evaluate the graphical user interface. The statistics analysis of the evaluation results show that the users in the community have positive perception of the usefulness of the application, the ease of use and intention to use the application. Community users with no prior experience with this technology were able to learn and understand the interface, recorded minimum errors and a high level of v precision during task performance when they interacted with the shop-owner graphic user interface. The voice user interface designed in this study consists of two flavours (dual tone multi-frequency input and voice input) for rural users. The evaluation results show that community users recorded higher tasks successes and minimum errors with the dual tone multi-frequency input interface than the voice only input interface. Also, a higher percentage of users prefer the dual tone multi-frequency input interface. The t-Test statistical analysis performed on the tasks completion times and error rate show that there was significant statistical difference between the dual tone multi-frequency input interface and the voice input interface. The interfaces were easy to learn, understand and use. Properly designed user interfaces that meet the experience and capabilities of low-literacy users in rural areas will improve usability and users‟ experiences. Adaptation of interfaces to users‟ culture and preferences will enhance information services accessibility among different user groups in different regions. This will promote technology acceptance in rural communities for socio-economic benefits. The user interfaces presented in this study can be adapted to different cultures to provide similar services for marginalised communities in developing countries

Die Nutzung von Mobiltelefonen während des Fahrens, vor allem das Lesen und Verfassen von Textnachrichten („Texting“), hat in den letzten Jahren drastisch zugenommen und stellt ein wachsendes Risiko für die Verkehrssicherheit dar. Es ist bekannt, dass visuell-manuelle Zweitaufgaben wie Texting die Fahrleistung negativ beeinträchtigen und das Unfallrisiko erheblich erhöhen. Gleichzeitig gibt es jedoch auch Hinweise darauf, dass Fahrer eine Reihe von selbstregulatorischen Verhaltensweisen nutzen, um die erhöhten Anforderungen durch die Zweitaufgabenbearbeitung beim Fahren auszugleichen. Die meisten Befunde zur selbstregulatorischen Verhaltensanpassung während der Zweitaufgabenbearbeitung beim Fahren beruhen allerdings auf experimentellen Studien, in denen die Versuchspersonen in künstlichen Verkehrsumgebungen fahren und oftmals nicht frei entscheiden können, ob und wann sie eine Zweitaufgabe aufnehmen. Ziel der vorliegenden Dissertation war es, selbstregulatorisches Verhalten basierend auf Daten aus sogenannten Naturalistic Driving Studies zu untersuchen und damit das Verständnis über ein Themengebiet zu verbessern, welches lange Zeit vernachlässigt wurde. Der Fokus lag dabei auf mobiltelefonbezogenen Aufgaben. Die Dissertation besteht aus fünf empirischen Artikeln sowie einer kurzen Synopse, in der theoretische Grundlagen zum Thema betrachtet sowie die Ergebnisse übergreifend zusammengefasst und diskutiert werden. Für die Studien, die den empirischen Artikeln zugrunde liegen, wurden Daten aus zwei großangelegten Naturalistic Driving Studies kodiert und analysiert – der US-amerikanischen SHRP 2 (Second Strategic Highway Research Program) Naturalistic Driving Study sowie der europäischen UDRIVE (European naturalistic Driving and Riding for Infrastructure & Vehicle safety and Environment) Naturalistic Driving Study. Das erste Forschungsziel der Dissertation bestand darin, selbstregulatorisches Verhalten in Form von Geschwindigkeitsanpassung zu untersuchen. Der Fokus lag dabei auf Fahrten, bei denen die Fahrer auf der Autobahn und im freien Verkehrsfluss fuhren. Für das Telefonieren mit dem Mobiltelefon ergab die Analyse der SHRP 2 Daten, dass Fahrer ihre Geschwindigkeit während des Telefonierens nicht reduzieren. Für Texting zeigten sich kleine Hinweise für eine Geschwindigkeitsanpassung, vor allem während des Fahrens mit höheren Geschwindigkeiten. Bei der Analyse der UDRIVE Daten konnten hingegen deutlichere Ergebnisse gefunden werden. Fahrer reduzierten ihre Geschwindigkeit nach dem Initiieren von Texting und erhöhten ihre Geschwindigkeit nach dem Beenden von Texting – in beiden Fällen um mehr als 2 km/h. Europäische Fahrer scheinen also „mehr“ selbstregulatorisches Verhalten zu zeigen als US-amerikanische Fahrer. Gründe für diese unterschiedlichen Befunde könnten in der Verkehrsinfrastruktur, der Fahrzeugausstattung sowie in den Stichprobencharakteristiken liegen. Das zweite Forschungsziel bezog sich auf die Identifikation der Orte, an denen das Mobiltelefon vor Beginn der mobiltelefonbezogenen Aufgabe verstaut wird, sowie deren Einfluss auf das Blickverhalten der Fahrer. Die Analyse der UDRIVE Daten zeigte, dass vor Beginn des Textings das Mobiltelefon zumeist offen und in Reichweite lag. Ähnliche Ergebnisse wurden bei der Analyse der SHRP 2 Daten für das Telefonieren gefunden. Die meisten Fahrer verstauten das Mobiltelefon in unmittelbarer Reichweite (z.B. auf dem Schoß). Bei einem Großteil dieser Fälle wurde darüber hinaus der Anruf vom Fahrer selbst initiiert. Dies lässt vermuten, dass sich Fahrer auf selbstinitiierte Anrufe vorbereiten und ihr Mobiltelefon in der Nähe verstauen, um den Aufwand des Suchens bzw. Greifens nach dem Mobiltelefon so gering wie möglich zu halten. Wenn sich das Mobiltelefon auf dem Beifahrersitz oder in der Tasche befand, war der Anruf zumeist eingehend. Die Analysen des Blickverhaltens in der Initiierungsphase eines Telefonats (d.h. wenn nach dem Mobiltelefon gesucht und gegriffen wird) zeigten, dass die Dauer der auf die Straße gerichteten Blicke tendenziell (allerdings nicht signifikant) zunimmt je weiter weg das Mobiltelefon verstaut wird, während kein Unterschied zwischen den Ablageorten hinsichtlich der Dauer der Blickabwendungen von der Straße erkennbar war. Dieser Befund legt nahe, dass Fahrer die Aufmerksamkeit, welche sie auf die primäre Fahraufgabe richten, in Abhängigkeit der Zweitaufgabenanforderung anpassen. Im Rahmen des dritten Forschungsziels der Dissertation wurden die Verkehrskontexte identifiziert, in denen Fahrer mobiltelefonbezogene Aufgaben vermehrt aufnehmen. Mit Ausnahme des Telefonierens initiierten die Fahrer mobiltelefonbezogene Aufgaben signifikant häufiger, wenn das Fahrzeug stand (z.B. an einer roten Ampel). Darüber hinaus wurde signifikant weniger getextet, wenn die Fahrer in einem konstanten Verkehrsfluss fuhren oder abbogen. Folglich scheinen Verkehrskontexte mit geringen Anforderungen an die primäre Fahraufgabe für die Aufnahme mobiltelefonbezogener Aufgaben präferiert zu werden. Dieser Befund konnte ebenfalls in einer weiteren Untersuchung bestätigt werden, bei welcher der Fokus auf Ampelsituationen lag. Texting wurde im Vergleich zum Telefonieren signifikant häufiger während des Stehens an der Ampel begonnen als auch beendet. Dies deutet daraufhin, dass Fahrer versuchen, die Dauer des Textings auf die Rotlichtphase zu beschränken. Aus den Blickanalysen ging hervor, dass Fahrer, die an der Ampel texteten, mehr als die Hälfte der Zeit auf das Mobiltelefon und somit nicht auf die Straße schauten. Es gab zudem einen beachtenswerten Teil an Fahrern, die Texting erst nach dem Wiederlosfahren beendeten, was das Situationsbewusstsein erheblich beeinträchtigen und sich damit negativ auf die Verkehrssicherheit auswirken kann. Die Ergebnisse dieser Dissertation zeigen, dass Daten aus Naturalistic Driving Studies nicht nur verwendet werden können, um bereits bestehende Befunde aus experimentellen Studien zu validieren, sondern auch um neue Erkenntnisse bezüglich selbstregulatorischen Verhaltens während der Zweitaufgabenbearbeitung beim Fahren unter natürlichen Verkehrsbedingungen zu gewinnen. Die vorliegende Arbeit leistet damit einen Forschungsbeitrag im Bereich der Fahrerablenkung. In zukünftigen Untersuchungen sollte das Zusammenspiel zwischen strategischen und operationalen Verhaltensweisen sowie der Einfluss von individuellen Faktoren auf die selbstregulatorische Verhaltensanpassung thematisiert werden. Darüber hinaus stellen die Befunde einen Ausgangspunkt für die Ableitung praktischer Maßnahmen dar. Zur Erhöhung der Verkehrssicherheit könnten beispielsweise sogenannte Workload-Management-Systeme den Fahrer während einer Zweitaufgabenbearbeitung in kritischen (z.B. während des Fahrens mit hohen Geschwindigkeiten) oder in vermeintlich einfachen Verkehrsumgebungen (z.B. während des Stehens an einer roten Ampel) unterstützen, sodass die Aufmerksamkeit (rechtzeitig) auf die primäre Fahraufgabe gelenkt wird.:Danksagung i Zusammenfassung iii Table of Contents vii Synopsis 1 1 Introduction 1 2 Cell phone related driver distraction 2 2.1 Prevalence of cell phone usage while driving 3 2.2 Effects of cell phone usage while driving on driving performance 4 3 Self-regulatory behavior adaptation 5 3.1 Trying to find a definition of self-regulatory behavior adaptation 6 3.2 Theoretical frameworks to explain drivers’ self-regulatory behavior adaptation 6 3.2.1 Task Difficulty Homeostasis (Fuller, 2005, 2008, 2011) 7 3.2.2 Behavioural Adaptation Model (Young, Regan, & Lee, 2009) 8 3.3 Types of self-regulatory behavior adaptation 9 3.3.1 Operational self-regulatory behavior adaptation 10 3.3.2 Strategic self-regulatory behavior adaptation 12 4 Naturalistic driving study – A useful method to investigate driving behavior? 13 4.1 SHRP 2 naturalistic driving study 17 4.2 UDRIVE naturalistic driving study 17 5 Research objectives 17 5.1 Assessing drivers’ speed behavior 18 5.2 Identifying cell phone storage location before initiating a cell phone task and assessing its impact on drivers’ glance behavior 18 5.3 Assessing the driving contexts that encourage drivers to initiate a cell phone task and getting some indications about potential safety implications associated with this behavior strategy 19 5.4 Integration of the research objectives into the theoretical frameworks 19 6 Summary and conclusion 20 6.1 Main findings of the dissertation 20 6.1.1 Drivers’ speed behavior when engaged in cell phone tasks 20 6.1.2 Drivers’ cell phone storage location before initiating a cell phone task and its impact on drivers’ glance behavior 21 6.1.3 Driving contexts that encourage drivers to initiate a cell phone task and potential safety implications associated with this behavior strategy 22 6.2 Overall discussion 23 6.2.1 Methodological considerations 23 6.2.2 Theoretical implications 25 6.2.3 Practical implications 28 6.3 Conclusion 30 7 References 31 Paper I 43 Paper II 55 Paper III 73 Paper IV 83 Paper V 93 Curriculum Vitae 105 Publications 109

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The thesis project underlines the importance of designing calm and subtle technologies, by exploring how mobile communicative technologies, such as cell phones, could notify their users about incoming information in a more natural, and non-intrusive manner. The aim of the thesis was to find a way for cell phones to act more appropriately in public and social settings, where they now often are considered intrusive due to their uninhibited manifestations.The thesis provides a theoretical understanding of how normative expectations of cell phone conduct are constituted and maintained within public and social settings. The theories are further grounded in practical work, where the project employ user centered design methods and techniques to, in a collaborative manner, together with users explore the research field to generate insights. Solutions have further been prototyped and evaluated together with users in their everyday settings.Taking inspiration from calm technology, the project looks into how information can be notified, in a more subtle manner in the periphery of the user’s attention. Users’ own priming abilities have been considered as a personal way to recognize the notification and to further associate it as relevant information.As a solution for intrusive cell phones, the thesis proposes Knot; a signature based notification system, which builds on friends’ abilities to recognize each other’s characteristic traits. The system consists of a notification rope, which is a free standing phone accessory that twists and turns, when new information is arriving to the user’s cell phone. It can present whom the information is from by shaping itself into the sender’s representative Knot-signature. If the user can recognize the signature, it will immediately trigger a meaningful association to the person who sent the information.The solution builds upon the restrictiveness between those who can associate a certain signature to a certain person, and those who cannot. For those who have the ability to associate to the signature, its role as a notifier will become meaningful and informative, while for others, who do not share this ability, the signature would be subtle and meaningless, and hence not interfering. The thesis exemplifies how interfaces could provide users with output in a more natural way, by considering users’ previous skills and knowledge, and primarily their priming abilities.

More than one billion people, almost one in six of the world's population, are now using GSM mobile phones. The situation in South Africa is no different from that in the rest of the world. The rise of mobile telephone usage in South Africa has been driven by a combination of factors such as demand, sector reform, the licensing of new competition, and the emergence of major strategic investors, such as Vodacom and MTN. It was estimated that by March 2005 there should be approximately 20 million cellular customers in South Africa. The growth in the South African cellular market is proportionate to the potential risks in an environment where organisations are continuously seeking ways of improving efficiency, cutting costs, and staying abreast of technological advances. Elements of risk control such as Safety, Health, and Environmental Management can no longer be left out of the equation while organisations in the GSM industry are considering increasing their networks to meet the demands of growth. Although risk assessments are not specifically defined in the Occupational Health and Safety Act (85 of 1993); Section 8 does, however, stipulate under the general duties of the employer that the employer must establish, as far as is reasonably practicable, which hazards to the health or safety of persons are attached to any work which is performed. This situation has changed with the promulgation of the Construction Regulations, GNR.1010 on 18 July 2003; which state that every contractor performing construction work shall, before the commencement of any construction work and during construction work, cause a risk assessment to be performed by a competent person appointed in writing, and that the risk assessment shall form part of the health and safety plan to be applied on the site. This requirement under the Construction Regulations will have a major impact on organisations in the GSM industry. Integrated Health, Safety and Environmental risk assessments have now become a prerequisite before considering any further expansion of the GSM network in South Africa. The relationship between the operational risk sub-disciplines of health, safety, and environmental management, as part of the risk-management function, has been established, and an operational risk-assessment model for the Global Systems Mobile Telecommunications industry in South Africa that measures occupational health, safety, and environmental management risks on an integrated basis has been developed. The risk assessment model for the South African GSM industry is based on assessing the frequency of an activity in relation to the impact on the organisation's business processes, incident/accident potential, financial impact, legal status, and the nature of ecological impact. / Business Management / D. Com. (Business Management)

This study investigates the customer-based brand equity of the major cellphone network service providers (Vodacom, MTN and Cell C) amongst principal estate agents registered with the Estate Agency Affairs Board in Gauteng. Secondary research covered the marketing environment of the major service providers. An extensive study of literature on branding, brand management and brand equity measurement was undertaken. An empirical study was conducted. Telephone interviews were used for initial contact and screening. An invitation to participate in the survey, with a link to a questionnaire, was e-mailed to qualified respondents. Cell C users were excluded from the quantitative analysis. There were several significant findings: Vodacom and MTN users are alike in terms of personal and estate agency-related demographics. With the exception of age and gender, the sample fits the stated descriptors of individuals in the LSM seven to LSM ten groups. Cronbach‘s alpha coefficient confirmed a high level of reliability (0.870) for the summated measurement scale developed as an indicator variable of customer-based brand equity and Vodacom and MTN‘s rating on the summated scale did not differ at a statistically significant level. The service provider used proved to be an important driver of loyalty, but overall satisfaction with the cellphone service does not differ statistically significantly between Vodacom and MTN users. Vodacom has established a much more favourable positioning on the brand association statements evaluated. Factor analysis identified five brand association dimensions that should be considered for measurement of brand associations. Multiple regression analysis identified the brand as a product dimension as the best predictor of customer-based brand equity. Vodacom received more favourable brand performance ratings than MTN. Factor analysis identified six brand performance dimensions that should be considered for inclusion when measuring brand performance. Multiple regression analysis identified the easy to use and one-stop-service dimensions as the best predictors of customer-based brand equity. The customer-based brand equity of the user group is moderate (16 out of 25, or 64%). / Business Management / D. Com. (Business Management)

Information, communication and broadcasting convergence is changing the business landscape in South Africa, as organisations adopt new converged information, communication technology (ICT) products and services to satisfy the needs of customers. Simultaneously, major changes are taking place in the South African telecommunications business environment creating new marketing opportunities and threats for Telkom SA, the only fixed line telecommunication operator in South Africa. Some of the findings of the study are • the commodization of the fixed line telecommunication network • political and regulatory changes are reshaping the telecommunications landscape by allowing the entry of new competitors • new technological innovations in Information Communication Technology (ICT) and mobile communication is driving change • social and economic change is fueling the speed of environmental change poor economic climate is quickening the competitive pace amongst South African businesses forcing them to attain efficiencies and effectiveness for survival • organisations worldwide are competing for limited resources and markets and turning to ICT to achieve their objectives • customer needs are changing - demanding better and innovative communication products and services - providing opportunities to competitors • the Internet is reshaping traditional business models as businesses are seeking to establish competitive advantages through the Internet • the migration of the Internet to the mobile telephony sector These changes are creating new marketing opportunities and threats for South African fixed line telecommunication operators and are threatening the survival of fixed line telecommunication operators worldwide and in South Africa. Information Technology, broadcasting and telecommunication technology convergence, has created many new ICT products and services opportunities that telecommunication competitors are offering existing customers of the fixed line operators network indicating lethargy from their side. In order for the fixed line operators to survive they must apply innovation and revise their strategic planning models. / Business Management / DCOM (Business Management)

The telecommunication market is growing at a very fast pace with the evolution of new technologies to support high speed throughput and the availability of a wide range of services and applications in the mobile networks. This has led to a need for communication service providers (CSPs) to shift their focus from network elements monitoring towards services monitoring and subscribers’ satisfaction by introducing the service quality management (SQM) and the customer experience management (CEM) that require fast responses to reduce the time to find and solve network problems, to ensure efficiency and proactive maintenance, to improve the quality of service (QoS) and the quality of experience (QoE) of the subscribers. While both the SQM and the CEM demand multiple information from different interfaces, managing multiple data sources adds an extra layer of complexity with the collection of data. While several studies and researches have been conducted for data analytics in mobile networks, most of them did not consider analytics based on the four dimensions involved in the mobile networks environment which are the subscriber, the handset, the service and the network element with multiple interface correlation. The main objective of this research was to develop mobile network analytics models applied to the 3G packet-switched domain by analysing data from the radio network with the Iub interface and the core network with the Gn interface to provide a fast root cause analysis (RCA) approach considering the four dimensions involved in the mobile networks. This was achieved by using the latest computer engineering advancements which are Big Data platforms and data mining techniques through machine learning algorithms. / Electrical and Mining Engineering / M. Tech. (Electrical Engineering)