We investigate, in this thesis, the use of Hierarchical Modulation (HM), a physical layer technique that enables to exploit multiuser diversity, for resource allocation in OFDMA-based systems with and without use of relaying, so as to improve the system capacity. HM allows the sharing of the resources, namely subcarriers and power, between users of different radio conditions by sending an additional stream to a user with good radio conditions on a subcarrier that was initially allocated to carry an original stream to a user with lower radio conditions. And this, without affecting the original user's rate nor the total amount of power assigned to the shared subcarrier. In the literature, most of the works that consider the use of HM focus solely on the physical layer performance, notably in terms of the bit error rate. And this for a static user scenario,i.e., with a fixed number of users in the system, each with an infinite service duration. This configuration however does not reflect the real system behavior where the number of users is dynamic, i.e., the users come to the system at random time epochs and leave it after a finite duration, corresponding to the completion of their services. The study of the system at the flow-level, as opposed to the packet level, for a dynamic user configuration, enables us to investigate the realistic relationship between capacity and demand and to quantify several system-level performance metrics, such as mean transfer times and blocking rates, which are meaningful both to the user and the network operator/provider.

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No description available.

There have been good arguments made for the development of aggressive affirmative action policies with the end goal of quickly moving black South Africans into corporate and high ranks within management of organisations. One of the central arguments in favour of aggressive AA policies is the risk of racial polarization post-apartheid should a quick fix not be initiated. It makes good business and economic sense for AA policies to be implemented as black consumers coupled with black managers will have the eventual end point of lower unemployment and crime, through job creation and security of the representative majority.

The three components model of empathy proposed by Decety and Jackson (2004) is currently the dominant model of empathy. The three components include: 1) the affective component (Simulation Theory), 2) emotional perspective taking, and 3) emotion regulation (self/other distinction). The purpose of the current study was to examine whether empathic perspective taking is dependent on context and to provide a behavioral basis for a follow-up fMRI study. More specifically, we wanted to know how body contexts (e.g. mood) and situational contexts (e.g. perceived fairness of a partner) affect emotional perspective taking. To examine the interaction between mood and perceived fairness of a partner, a 2 (mood group: neutral vs. negative) × 2 (fairness condition: unfair partner vs. fair partner) between-groups experimental design was employed. Mood induction videos were employed for the mood manipulation and participants played either a fair or unfair preprogrammed partner in a modified ultimatum game. After both manipulations, three measures were used to assess perspective taking and several post-game behavioral measures were also employed. Results were obtained from 73 participants (age: 18-22; female = 46, ~18 in each condition). The results demonstrated that participants in the negative mood had more difficulty empathizing with unfair partners and had a greater desire for revenge against them than participants in a neutral mood in the same unfair situations. Therefore, human empathy is not constant, but varies depending on a variety of contexts. We can now use this paradigm for a future fMRI study to investigate the neural substrates underlying this context dependency with a particular emphasis on the frontopolar cortex and the nucleus accumbens.

The Internet has grown enormously since the introduction of the World Wide Web in the early 90's. The evolution and wide spread deployment of cellular networks have contributed to make the Internet accessible to more people in more places. The cellular networks of today offer data rates high enough for most Internet services. Even so, the service quality experienced by the users is often lower than in wired networks. The performance of TCP has a large impact on user experience. Therefore, we investigate TCP in cellular networks and propose functionality to improve the situation for TCP. We have studied sources of delay and data loss, such as link layer retransmissions, queuing, and handover. Measurements were conducted in a GSM/GPRS testbed. The results indicate that TCP interact efficiently with the GSM link layer protocol in most cases. From experiments of queuing in GPRS, we conclude that with a smaller buffer delay is reduced significantly, but that TCP throughput is about the same as with a larger buffer. Furthermore, we propose an improved buffer management when a connection loses all its resources to traffic with higher priority. We also propose a scheme for data forwarding to avoid negative impact on TCP during handover for WINNER, a research system that was used to test ideas for LTE. The achievable data rates in cellular networks are limited by inter-cell interference that vary over the cell. Inter-cell interference can be mitigated with Coordinated Multipoint techniques (CoMP), techniques that currently are being standardized for LTE-Advanced. System wide CoMP is, however, not an option, since it would be too resource consuming. In order to limit the required resources for CoMP, we propose an approach to select a subset of users for CoMP that is based on user experience. Simulation results indicate that user experience, represented with application utility,  and fairness are improved compared to if only rate is considered in the user selection. / The Internet has grown enormously since the introduction of the World Wide Web in the early 90's. The evolution and wide spread deployment of cellular networks have contributed to make the Internet accessible to more people in more places. The cellular networks of today offer data rates high enough for most Internet services. Even so, the service quality experienced by the users is often lower than in wired networks. The performance of TCP has a large impact on user experience. Therefore, we investigate TCP in cellular networks and propose functionality to improve the situation for TCP. We have studied sources of delay and data loss, such as link layer retransmissions, queuing, and handover. The achievable data rates in cellular networks are limited by inter-cell interference that vary over the cell area. Inter-cell interference can be mitigated with Coordinated Multipoint techniques (CoMP), techniques that currently are being standardized for LTE-Advanced. System wide CoMP is, however, not an option, since it would be too resource consuming. In order to limit the required resources for CoMP, we propose an approach to select a subset of the users for CoMP that is based on user experience.

The ability to establish and maintain trust is regarded as a critical modern leadership skill. However, different conceptualisations of trust saw to it that the empirical and theoretical sides of research did not merge. As a result, trust has been studied in a variety of different ways and resulted in a varied and fragmented knowledge base, which this study attempts to address. The objectives of this study were to investigate conceptualizations of trust as perceived by middle- and senior level managers in a military medical basis in order to provide recommendations to management on how to build trust. Research was conducted in two phases of investigation. In phase 1 a literature review of the concept was conducted by analyzing and categorizing definitions and frameworks currently in use. In the second phase an empirical investigation was conducted by means of a descriptive and explorative qualitative research design and the use of a non-probability purposive sampling technique. The results showed that three proposed factors of trustworthiness (ability, benevolence and integrity), effective communication as well as perceived justice and fairness are fundamental to the establishment of trust. It is evident that management should draft a strategic plan to ensure that trust is established and maintained on a sustainable basis. The findings will contribute to a better understanding of the essential nature of trust and assist management in an effective approach to master trust as an essential leadership skill in order to successfully enhance business reputation and outcomes. / Thesis (MBA)--North-West University, Potchefstroom Campus, 2011

The ability to establish and maintain trust is regarded as a critical modern leadership skill. However, different conceptualisations of trust saw to it that the empirical and theoretical sides of research did not merge. As a result, trust has been studied in a variety of different ways and resulted in a varied and fragmented knowledge base, which this study attempts to address. The objectives of this study were to investigate conceptualizations of trust as perceived by middle- and senior level managers in a military medical basis in order to provide recommendations to management on how to build trust. Research was conducted in two phases of investigation. In phase 1 a literature review of the concept was conducted by analyzing and categorizing definitions and frameworks currently in use. In the second phase an empirical investigation was conducted by means of a descriptive and explorative qualitative research design and the use of a non-probability purposive sampling technique. The results showed that three proposed factors of trustworthiness (ability, benevolence and integrity), effective communication as well as perceived justice and fairness are fundamental to the establishment of trust. It is evident that management should draft a strategic plan to ensure that trust is established and maintained on a sustainable basis. The findings will contribute to a better understanding of the essential nature of trust and assist management in an effective approach to master trust as an essential leadership skill in order to successfully enhance business reputation and outcomes. / Thesis (MBA)--North-West University, Potchefstroom Campus, 2011

Climate change is the greatest environmental international problem facing the world today. This paper begins with a review of the climate change regime to date showing the mistakes that were made leading to failure in Copenhagen. It looks at China’s unique position in the international community and concludes that a meaningful climate change solution is not possible without China’s participation. It examines the concepts of CBDR and fairness to determine whether it is fair for the world to demand China’s participation. It looks at characteristics which should be present in a fair climate change solution, and concludes with a brief look at international trade law to determine what alternatives would be available to a coalition of willing states to encourage China’s participation in a global solution or, in a worst case scenario, to form an effective solution without China’s willing participation.

Climate change is the greatest environmental international problem facing the world today. This paper begins with a review of the climate change regime to date showing the mistakes that were made leading to failure in Copenhagen. It looks at China’s unique position in the international community and concludes that a meaningful climate change solution is not possible without China’s participation. It examines the concepts of CBDR and fairness to determine whether it is fair for the world to demand China’s participation. It looks at characteristics which should be present in a fair climate change solution, and concludes with a brief look at international trade law to determine what alternatives would be available to a coalition of willing states to encourage China’s participation in a global solution or, in a worst case scenario, to form an effective solution without China’s willing participation.