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Text in English with abstracts in English, isiZulu and Xhosa / This research applies the Near Repeat Calculator (NRC) to identify near repeat residential burglary patterns in the Hillcrest (KZN) policing area for the first time. A total of 490 residential burglaries, over a 12-month period, reported to Hillcrest police station were mapped (geocoded) and the near repeat calculations were visualised using the Geographic Information Systems (GIS). The month-to-month near repeat calculations are analysed and suggest that the NRC is a valuable tool that can predict the space-time locations of near repeat residential burglaries in the Hillcrest policing area. / Lolu cwaningo lusebenzisa i-Near Repeat Calculator (NRC) ukuhlonza amaphethini okuphindaphindeka kwezigameko zokugqekezwa kwamakhaya endaweni eyenganyelwe yisiteshi samaphoyisa sase-Hillcrest (KZN). Izigameko zokugqekezwa kwamakhaya ezingama-490 ezabikwa esiteshini samaphoyisa sase- Hillcrest esikhathini esiyizinyanga eziyi-12 zaboniswa emfanekisweni webalazwe lendawo (geocoded) futhi izilinganiso zamathuba okuthi ziphinde zenzeke izigameko zokugqekezwa kwamakhaya zaboniswa ngokuthi kusetshenziswe umfanekiso owenziwe nge-Geographic Information Systems (GIS). Kwahlaziywa amathuba enyanga nenyanga okuphindaphindeka kwezigameko, futhi imiphumela eyatholakala kulokhu iyabonisa ukuthi i-NRC iyithuluzi eliwusizo impela elingabikezela izindawo nesikhathi lapho kungaphinda futhi kwenzeke khona izigameko zokugqekezwa kwamakhaya endaweni eyenganyelwe yisiteshi samaphoyisa sase-Hillcrest. / Olu phando lusebenzisa uhlobo lokubala olwaziwa ngokuba yiNear Repeat Calculator (NRC) ngenjongo yokubona isimbo sokuqhekezwa kwezindlu zabantu kummandla ophantsi kwamapolisa aseHillcrest (eKZN). Kuqwalaselwe ama-490 eziganeko zoqhekezo lwemizi ezaxelwa emapoliseni aseHillcrest kwisithuba seenyanga ezili-12, kwaye uhlobo lokubala oluqikelela ukuphindwa kweziganeko zoqhekezo luboniswe ngokusebenzisa inkqubo ekuthiwa yiGeographic Information Systems (GIS). Ubalo oluqikelela ukuphindwa kweziganeko luphononongiwe kwinyanga nenyanga, kwaye iziphumo zibonisa ukuba iNRC sisixhobo esinexabiso, esinokukwazi ukuqikelela indawo nexesha apho kunokuphinda kuqhekezwe khona kummandla ophantsi kwamapolisa aseHillcrest. / Criminology and Security Science / M.A. (Criminology)

Arts festivals form a large part of the South African culture originally as many local communities began to share their culture with visitors by means of arts festivals. This has grown into a large industry that has tremendous financial gain for the hosting communities. With over 500 arts festivals each year in South Africa alone, visitors are certain to find a festival to satisfy their specific needs and wants. Therefore, with so many genres available, each festival has created its own niche market and loyal customer base. An extensive literature study was conducted for the purpose of this thesis and it was found that research of small to medium arts festivals has been neglected. This finding motivated the main theme of this research. As mentioned earlier, there are so many genres available that the festival organisers may experience difficulty when deciding what to offer and how many genres to offer in order to still be sustainable and attract a sufficient number of visitors. Furthermore, the large number of arts festivals organised each year makes it increasingly difficult for festivals to build a loyal client base. First-time visitors can be converted into repeat visitors if the marketing strategy is precise. Repeat visitors, as stated in the literature, results in a sustainable income for each festival. Another question that motivated the research was the location of the three arts festivals (Innibos, Vryfees, and Kierieklapper). Three arts festivals in three provinces makes an interesting study to determine whether there is a difference in the three types of visitors that they attract and the spending patterns at each festival. While addressing the problems stated above, this study produced the following three articles: * Article 1: ―Determinants of spending at Vryfees with a focus on genres‖. * Article 2: ―First-time versus repeat visitors at Innibos Arts Festival‖. * Article 3: ―Role of location in the attendance and spending of festinos‖. Article 1 investigates spending determinants that influence visitor expenditure on the different genres offered at the Vryfees Festival in Bloemfontein, based on a survey conducted in 2011. The research is based on the notion that different genres have different spending patterns. Article 2 focuses on the differences and/or similarities between first-time and repeat visitors at the Innibos Arts Festival as an alternative approach to market segmentation. Lastly, the third article focuses on three different arts festivals in three different locations in South Africa. The research was conducted by means of a visitor survey at the three arts festivals during the same year with questionnaires administered at Innibos (428), Vryfees (336), and Kierieklapper (202) respectively. The most significant contributions of this study can be summarised as follows: * the tourist spending behaviour in regards to the difference between first-time and repeat visitors is significant and can be considered an important spending determinant; * the tourist spending behaviour in terms of length of stay between first-time visitors and repeat visitors is significantly different, suggesting that familiarity with the destination (as the repeat visitors are) has an important impact; * different locations attract their own type of tourists and certain locations receive a higher economic injection than other provinces do because of the type of festival held. All three arts festivals attract mainly Afrikaans speaking attendees; and for the first time, a comparative study has been conducted on three arts festivals targeting the Afrikaans speaking community. Additionally, this is the first time a comparative study was conducted on three small to medium arts festivals located in three different provinces; and * the developed spending model described in the last chapter of this thesis can assist the festival organisers with future festival marketing to improve their income and marketing strategy. / PhD (Tourism Management), North-West University, Potchefstroom Campus, 2014

Arts festivals form a large part of the South African culture originally as many local communities began to share their culture with visitors by means of arts festivals. This has grown into a large industry that has tremendous financial gain for the hosting communities. With over 500 arts festivals each year in South Africa alone, visitors are certain to find a festival to satisfy their specific needs and wants. Therefore, with so many genres available, each festival has created its own niche market and loyal customer base. An extensive literature study was conducted for the purpose of this thesis and it was found that research of small to medium arts festivals has been neglected. This finding motivated the main theme of this research. As mentioned earlier, there are so many genres available that the festival organisers may experience difficulty when deciding what to offer and how many genres to offer in order to still be sustainable and attract a sufficient number of visitors. Furthermore, the large number of arts festivals organised each year makes it increasingly difficult for festivals to build a loyal client base. First-time visitors can be converted into repeat visitors if the marketing strategy is precise. Repeat visitors, as stated in the literature, results in a sustainable income for each festival. Another question that motivated the research was the location of the three arts festivals (Innibos, Vryfees, and Kierieklapper). Three arts festivals in three provinces makes an interesting study to determine whether there is a difference in the three types of visitors that they attract and the spending patterns at each festival. While addressing the problems stated above, this study produced the following three articles: * Article 1: ―Determinants of spending at Vryfees with a focus on genres‖. * Article 2: ―First-time versus repeat visitors at Innibos Arts Festival‖. * Article 3: ―Role of location in the attendance and spending of festinos‖. Article 1 investigates spending determinants that influence visitor expenditure on the different genres offered at the Vryfees Festival in Bloemfontein, based on a survey conducted in 2011. The research is based on the notion that different genres have different spending patterns. Article 2 focuses on the differences and/or similarities between first-time and repeat visitors at the Innibos Arts Festival as an alternative approach to market segmentation. Lastly, the third article focuses on three different arts festivals in three different locations in South Africa. The research was conducted by means of a visitor survey at the three arts festivals during the same year with questionnaires administered at Innibos (428), Vryfees (336), and Kierieklapper (202) respectively. The most significant contributions of this study can be summarised as follows: * the tourist spending behaviour in regards to the difference between first-time and repeat visitors is significant and can be considered an important spending determinant; * the tourist spending behaviour in terms of length of stay between first-time visitors and repeat visitors is significantly different, suggesting that familiarity with the destination (as the repeat visitors are) has an important impact; * different locations attract their own type of tourists and certain locations receive a higher economic injection than other provinces do because of the type of festival held. All three arts festivals attract mainly Afrikaans speaking attendees; and for the first time, a comparative study has been conducted on three arts festivals targeting the Afrikaans speaking community. Additionally, this is the first time a comparative study was conducted on three small to medium arts festivals located in three different provinces; and * the developed spending model described in the last chapter of this thesis can assist the festival organisers with future festival marketing to improve their income and marketing strategy. / PhD (Tourism Management), North-West University, Potchefstroom Campus, 2014

When designing architectures and protocols for data traffic requiring real-time services, one of the major design goals is to guarantee that traffic deadlines can be met. However, many real-time applications also have additional requirements such as high throughput, high reliability, or energy efficiency. High-performance embedded systems communicating heterogeneous traffic with high bandwidth and strict timing requirements are in need of more efficient communication solutions, while wireless industrial applications, communicating control data, require support of reliability and guarantees of real-time predictability at the same time. To meet the requirements of high-performance embedded systems, this thesis work proposes two multi-wavelength high-speed passive optical networks. To enable reliable wireless industrial communications, a framework in­corporating carefully scheduled retransmissions is developed. All solutions are based on a single-hop star topology, predictable Medium Access Control algorithms and Earliest Deadline First scheduling, centrally controlled by a master node. Further, real-time schedulability analysis is used as admission control policy to provide delay guarantees for hard real-time traffic. For high-performance embedded systems an optical star network with an Arrayed Waveguide Grating placed in the centre is suggested. The design combines spatial wavelength re­use with fixed-tuned and tuneable transceivers in the end nodes, enabling simultaneous transmis­sion of both control and data traffic. This, in turn, permits efficient support of heterogeneous traf­fic with both hard and soft real-time constraints. By analyzing traffic dependencies in this mul­tichannel network, and adapting the real-time schedulability analysis to incorporate these traffic dependencies, a considerable increase of the possible guaranteed throughput for hard real-time traffic can be obtained. Most industrial applications require using existing standards such as IEEE 802.11 or IEEE 802.15.4 for interoperability and cost efficiency. However, these standards do not provide predict­able channel access, and thus real-time guarantees cannot be given. A framework is therefore de­veloped, combining transport layer retransmissions with real-time analysis admission control, which has been adapted to consider retransmissions. It can be placed on top of many underlying communication technologies, exemplified in our work by the two aforementioned wireless stan­dards. To enable a higher data rate than pure IEEE 802.15.4, but still maintaining its energy saving properties, two multichannel network architectures based on IEEE 802.15.4 and encompassing the framework are designed. The proposed architectures are evaluated in terms of reliability, utiliza­tion, delay, complexity, scalability and energy efficiency and it is concluded that performance is enhanced through redundancy in the time and frequency domains.

PolyHistidine repeats and DYRK1A: from the localization to the functionEl principal objectiu d'aquesta tesi ha estat el d'esbrinar noves funcions de la proteína quinasa DYRK1A en el nucli cel.lular. Donat que el domini de repetició d'histidines de DYRK1A dirigeix la proteína al compartiment d'speckles nuclears, aquesta propietat ha estat utilitzada per adreçar aquesta pregunta. Els resultats obtinguts en aquesta tesi han permès proposar els homopolímers d'histidina com una nova i general senyal de localització a speckles nuclears. Proteïnes amb segments de polihistidines, la majoria d'elles factors de transcripció, mostren un comportament intranuclear dinàmic, compatible amb un model en el quèl diferents dominis d'interacció competeixen entre ells pel reclutament de la proteína a diferents subcompartiments nuclears. El mecanisme molecular que media l'acumulació a speckles de les proteïnes amb polihistines s'ha estudiat utilitzant DYRK1A com a model. Els resultats obtinguts exclouen la unió a l'RNA com a mecanisme de reclutament i concloure que, aquest, ocorre mitjançant la interacció amb proteïnes residents. S'han identificat dues noves proteïnes interactores per a DYRK1A, l'RNA polimerasa II i el factor de transcripció Brn-3b. La fosforilació de DYRK1A sobre el domini C-terminal o CTD de l'RNA polimerasa II suggereix una funció directa de la quinasa en el procés de transcripció o del seu acoblament al processament d'RNAs missatgers. La fosforilació de DYRK1A sobre el domini d'activació de Brn-3b sembla regular positivament l'activitat transcripcional d'aquest factor. Aquests resultats indiquen una funció activa de DYRK1A en la regulació de la transcripció gènica, tant directament sobre la maquinària transcripcional com indirectament, modulant l'activitat de factors de transcripció. PolyHistidine repeats and DYRK1A: from the localization to the functionThe main objective of this thesis work has been to identify new roles for the protein kinase DYRK1A in the cell nucleus. Given that a histidine repeat in DYRK1A targets the protein to the nuclear speckle compartment, this property has been used as a tool to approach the question. The results obtained in this thesis work have allowed proposing homopolymeric histidine runs as a novel and general nuclear speckle-directing signal. Proteins with polyHistidine segments, mostly transcription factors, present a dynamic intranuclear behaviour compatible with a model in which distinct interacting domains compete for recruiting elements within the nucleus. The molecular mechanisms that mediate speckle accumulation have been studied in DYRK1A as a model system. The results allow excluding RNA binding as the recruiting mechanism and concluding that targeting is mediated by interaction with speckle-resident proteins. Two novel DYRK1A interactors have been identified during the study, the RNA polymerase II and the transcription factor Brn-3b. DYRK1A phosphorylation of the C-terminal domain or CTD of the RNA polymerase II suggests a direct role of DYRK1A on transcription or coupling of transcription with RNA processing. DYRK1A phosphorylation of Brn-3b within its activation domain seems to positively regulate Brn-3b transcriptional activity. These results confirm an active role for DYRK1A in gene transcription regulation both direct on the transcriptional machinery and indirect by modulating the activity of transcription factors.

Due to the highly-varying wireless channels over time, frequency, and space domains, statistical QoS provisioning, instead of deterministic QoS guarantees, has become a recognized feature in the next-generation wireless networks. In this dissertation, we study the adaptive wireless resource allocation problems for statistical QoS provisioning, such as guaranteeing the specified delay-bound violation probability, upper-bounding the average loss-rate, optimizing the average goodput/throughput, etc., in several typical types of mobile wireless networks. In the first part of this dissertation, we study the statistical QoS provisioning for mobile multicast through the adaptive resource allocations, where different multicast receivers attempt to receive the common messages from a single base-station sender over broadcast fading channels. Because of the heterogeneous fading across different multicast receivers, both instantaneously and statistically, how to design the efficient adaptive rate control and resource allocation for wireless multicast is a widely cited open problem. We first study the time-sharing based goodput-optimization problem for non-realtime multicast services. Then, to more comprehensively characterize the QoS provisioning problems for mobile multicast with diverse QoS requirements, we further integrate the statistical delay-QoS control techniques — effective capacity theory, statistical loss-rate control, and information theory to propose a QoS-driven optimization framework. Applying this framework and solving for the corresponding optimization problem, we identify the optimal tradeoff among statistical delay-QoS requirements, sustainable traffic load, and the average loss rate through the adaptive resource allocations and queue management. Furthermore, we study the adaptive resource allocation problems for multi-layer video multicast to satisfy diverse statistical delay and loss QoS requirements over different video layers. In addition, we derive the efficient adaptive erasure-correction coding scheme for the packet-level multicast, where the erasure-correction code is dynamically constructed based on multicast receivers’ packet-loss statuses, to achieve high error-control efficiency in mobile multicast networks. In the second part of this dissertation, we design the adaptive resource allocation schemes for QoS provisioning in unicast based wireless networks, with emphasis on statistical delay-QoS guarantees. First, we develop the QoS-driven time-slot and power allocation schemes for multi-user downlink transmissions (with independent messages) in cellular networks to maximize the delay-QoS-constrained sum system throughput. Second, we propose the delay-QoS-aware base-station selection schemes in distributed multiple-input-multiple-output systems. Third, we study the queueaware spectrum sensing in cognitive radio networks for statistical delay-QoS provisioning. Analyses and simulations are presented to show the advantages of our proposed schemes and the impact of delay-QoS requirements on adaptive resource allocations in various environments.

IEEE 802.11 wireless LANs operating in the infrastructure mode are extremely popular and have seen widespread deployment because of their convenience and cost efficiency. A large number of research studies have investigated the performance of DCF, the default MAC protocol in 802.11 WLANs. Previous studies have pointed out several performance problems caused by the interaction of DCF in infrastructure-based WLANs. This thesis addresses a few of these issues. In the first part of the thesis, we address the issue of head-of-line (HOL) blocking at the Access Point (AP) in infrastructure WLANs. We use a cooperative ARQ scheme to resolve the obstruction at the AP queue. We analytically study the performance of our scheme in a single cell IEEE 802.11 infrastructure WLAN under a TCP controlled file download scenario and validate our analysis by extensive simulations. Both analysis and simulation results show considerable increase in system throughput with the cooperative ARQ scheme. We further examine the delay performance of the ARQ scheme in the presence of both elastic TCP traffic and delay sensitive VoIP traffic. Simulations results show that our scheme decreases the delay in the downlink for VoIP packets significantly while simultaneously providing considerable gains in the TCP download throughput. Next, we propose a joint uplink/downlink opportunistic scheduling scheme for maximising system throughput in infrastructure WLANs. We first solve the uplink/downlink unfairness that exists in infrastructure WLANs by maintaining a separate queue and a backoff timer at the AP for each mobile station (STA). We also increase the system throughput by making the backoff timer a function of the channel gains. We analyse the I performance of our scheme under symmetric UDP traffic with i. i. d. channel conditions. Finally, we discuss several opportunistic scheduling policies which aim to increase the system throughput while satisfying certain Quality of Service (QoS) objectives. The standard IEEE 802.11 DCF protocol only offers best-effort services and does not provide any QoS guarantees. Providing QoS in 802.11 networks with time varying channel conditions has proven to be a challenge. We show by simulations that by an appropriate choice of the scheduling metric in our opportunistic scheduling scheme, different QOS objectives like maximizing weighted system sum throughput, minimum rate guarantees and throughput optimality can be attained.