Vehicular Ad hoc Network (VANET) is a special kind of Mobile Ad hoc Network (MANET) and is a key enabling technology for Intelligent Transportation Systems (ITS). It plays an important role in the deployment of a large scale of both safety and non-safety applications. Among non-safety applications, an important and challenging area is the provision of information about roadside services advertisement and discovery. In this work, we adopted the beaconing strategy and opportunistic vehicular communications to address the problem of roadside services advertisement and discovery on the highways. Our approach offers several advantages over the traditional billboard method, e.g., low cost, targeting a large number of customers in a real time, more control over the advertisement campaign, dynamic content updating, and discovery of services far ahead of the business region. For advertising roadside services, we followed the push-based advertisement strategy and relied on Infrastructure-to-Vehicle (I2V) communications only. On the other hand, for discovering these services by the drivers, we used pull-based advertisement strategy and opportunistic Vehicle-to-Vehicle (V2V) communications. In order to contribute to the advertisement campaign, we used the store-carry-and-response mechanism. Our first contribution is the Extended Opportunistic Service Discovery Protocol (EOSDP). EOSDP implements and extends the original version of Opportunistic Service Discovery Protocol (OSDP) via simulation experiments. We used Simulation of Urban Mobility (SUMO), Objective Modular Network Testbed in C++ (OMNET++), and Vehicles in network simulation (Veins) simulators. Our second contribution is Service Advertisement Protocol (SADP). SADP is a lightweight beaconing-based services advertisement protocol for VANETs. It does not require the Internet connection for advertising the roadside services. Moreover, SADP modeling is based on VANETs standard protocols. The performance of SADP was evaluated in a congested highway scenario with varying speed of vehicles and under different broadcast frequencies. Our last contribution is Commercial Services Discovery Protocol (CSDP). Like the previous protocol, CSDP is a lightweight beaconing-based services discovery protocol for VANETs. CSDP is infrastructureless protocol which only depends on opportunistic V2V communications for roadside services discovery. The protocol was implemented in congested highway scenario and extensive set of simulation experiments were performed to evaluate its performance under different parameters, e.g., Query Interval (QI), Query Attempts (QA), and Time to Live (TTL). / Vehicular Ad hoc Network (VANET) é um tipo especial de Mobile Ad hoc Network (MANET) e é uma tecnologia chave para apoiar os Sistemas Inteligentes de Transporte (ITSs). Ela desempenha um papel importante na implantação em grande escala das aplicações do tipo safety e non-safety. Dentre as aplicações non-safety, uma área importante e desafiadora é descoberta e divulgação de informação sobre serviços. Neste trabalho, nós adotamos a estratégia de beaconing e as comunicações veiculares oportunistas para resolver o problema da descoberta e divulgação de serviços ao longo de rodovias. Nossa abordagem oferece várias vantagens em relação aos métodos tradicionais usando painéis, painéis eletrônicos digitais e outdoors, por exemplo. Baixo custo, atinge um grande número de clientes em tempo real, maior controle sobre a campanha de propaganda, atualização dinâmica de conteúdo e descoberta de serviços antes de alcançar a região de negócio são algumas delas. Para a divulgação de serviços ao longo de rodovias, seguimos a estratégia de publicidade push-based e usamos somente comunicações do tipo Infrastructure-to-Vehicle (I2V). Por outro lado, para a descoberta destes serviços pelos motoristas, utilizamos a estratégia de publicidade pull-based e comunicações oportunistas do tipo Vehicle-to-Vehicle (V2V). A fim de contribuir para a campanha de propagandas, foi utilizado o mecanismo store-carry-and-response. Nossa primeira contribuição é o Extended Opportunistic Service Discovery Protocol (EOSDP). O EOSDP implementa e estende a versão original do Opportunistic Service Discovery Protocol (OSDP) via experimentos por simulação. Nós utilizamos os simuladores Simulation of Urban Mobility (SUMO), Objective Modular Network Testbed in C++ (OMNET++) e o Vehicles in network simulation (Veins). Nossa segunda contribuição é o Service Advertisement Protocol (SADP). SADP é um protocolo leve baseado na estratégia de beaconing para divulgação de serviços em VANETs. Ele não requer conexão com a Internet para anunciar os serviços nas margens das rodovias. Além disso, a modelagem do SADP é baseada no padrão de protocolos VANETs. O desempenho do SADP foi avaliado em um cenário de rodovia congestionada, com velocidades variáveis dos veículos e sob diferentes frequências de comunicação broadcast. Por fim, apresentamos o nosso último protocolo chamado Commercial Services Discovery Protocol (CSDP). Como o protocolo anterior, o CSDP é um protocolo leve para descoberta de serviços baseado em beaconing para VANETs. O CSDP depende somente de comunicações V2V oportunistas para a descoberta de serviços ao longo de rodovias. O protocolo foi implementado no cenário de uma rodovia congestionada e avaliado com um extenso conjunto de experimentos de simulação, sob diferentes parâmetros como, por exemplo, Query Interval (QI), Query Attempts (QA) e Time to Live (TTL).

Submitted by Maria Aparecida (cidazen@gmail.com) on 2017-08-18T14:43:06Z No. of bitstreams: 1 Gilberto.pdf: 2769310 bytes, checksum: 210d2e0115f0c134b325cbf3a2354263 (MD5) / Made available in DSpace on 2017-08-18T14:43:06Z (GMT). No. of bitstreams: 1 Gilberto.pdf: 2769310 bytes, checksum: 210d2e0115f0c134b325cbf3a2354263 (MD5) Previous issue date: 2009-02-13 / CAPES / During the development of Grid middleware systems, researchers often employ simulation tools and techniques for validating new concepts and implementations. Simulation tools play a fundamental role on the development of Grid middleware systems since: (a) researchers often do not have access to huge Grid testbed environments, limiting the capacity for evaluating situations that demand high amount of resources; (b) it is difficult to explore in large scale application and resources scenarios involving several users in a repetitive and controlled way, due to the dynamic nature of Grid environments; (c) real Grid applications usually consume great amount of time, ranging from a few hours to even weeks. This work describes OGST, an object-oriented discrete event simulator whose main objective is to assist developers of opportunistic Grid middleware on validating new concepts and implementations. The preliminary motivation for OGST development was to provide a way for evaluating the behavior of scheduling algorithms commonly used on Grid environments under different execution environment conditions and the investigation of adaptive scheduling approaches. It was carefully designed to take into consideration the dynamics of opportunistic Grids, providing a set of features that hasten the development of simulations that takes into consideration the dynamism of the execution environment. The simulator was developed in the context of the InteGrade project, but was designed to allow the simulation of generic opportunistic Grids in order to be applied by other Grid middleware research projects. / Durante o desenvolvimento de sistemas de middleware de grade, pesquisadores freqüentemente empregam técnicas e ferramentas de simulação para valida- ção de novos conceitos e implementações. Ferramentas de simulação têm um papel fundamental no desenvolvimento de sistemas de middleware de grade uma vez que: (a) pesquisadores freqüentemente não têm acesso a grandes ambientes de grade para testes, limitando a capacidade para avaliar situações que demandam por uma grande quantidade de recursos; (b) é difícil explorar cenários com recursos e aplicações em larga escala envolvendo diversos usuários de forma repetitiva e controlada, devido à natureza dinâmica de ambientes de grade; (c) aplicações reais da grade geralmente consomem muito tempo, de poucas horas até mesmo a semanas. Este trabalho descreve o OGST, um simulador de eventos discretos orientado a objetos cujo principal objetivo é auxiliar desenvolvedores de sistemas de middleware de grade oportunista na validação de novos conceitos e implementações. A motivação preliminar para o desenvolvimento do OGST foi prover um caminho para avaliar o comportamento de algoritmos de escalonamento comumente usados em ambientes de grade sob diferentes condições do ambiente de execução e a investigação de abordagens de escalonamento adaptativo. Ele foi cuidadosamente projetado para levar em consideração a dinâmica de grades oportunistas, provendo um conjunto de funcionalidades que agilizam o desenvolvimento de simulações que consideram o dinamismo do ambiente de execução. O simulador foi desenvolvido no contexto do projeto InteGrade, mas foi projetado para permitir a simulação de grades oportunistas de uma maneira em geral com o propósito de ser aplicado a outros projetos de pesquisa envolvendo middleware de grades.

Vehicular Ad hoc Network (VANET) is a special kind of Mobile Ad hoc Network (MANET) and is a key enabling technology for Intelligent Transportation Systems (ITS). It plays an important role in the deployment of a large scale of both safety and non-safety applications. Among non-safety applications, an important and challenging area is the provision of information about roadside services advertisement and discovery. In this work, we adopted the beaconing strategy and opportunistic vehicular communications to address the problem of roadside services advertisement and discovery on the highways. Our approach offers several advantages over the traditional billboard method, e.g., low cost, targeting a large number of customers in a real time, more control over the advertisement campaign, dynamic content updating, and discovery of services far ahead of the business region. For advertising roadside services, we followed the push-based advertisement strategy and relied on Infrastructure-to-Vehicle (I2V) communications only. On the other hand, for discovering these services by the drivers, we used pull-based advertisement strategy and opportunistic Vehicle-to-Vehicle (V2V) communications. In order to contribute to the advertisement campaign, we used the store-carry-and-response mechanism. Our first contribution is the Extended Opportunistic Service Discovery Protocol (EOSDP). EOSDP implements and extends the original version of Opportunistic Service Discovery Protocol (OSDP) via simulation experiments. We used Simulation of Urban Mobility (SUMO), Objective Modular Network Testbed in C++ (OMNET++), and Vehicles in network simulation (Veins) simulators. Our second contribution is Service Advertisement Protocol (SADP). SADP is a lightweight beaconing-based services advertisement protocol for VANETs. It does not require the Internet connection for advertising the roadside services. Moreover, SADP modeling is based on VANETs standard protocols. The performance of SADP was evaluated in a congested highway scenario with varying speed of vehicles and under different broadcast frequencies. Our last contribution is Commercial Services Discovery Protocol (CSDP). Like the previous protocol, CSDP is a lightweight beaconing-based services discovery protocol for VANETs. CSDP is infrastructureless protocol which only depends on opportunistic V2V communications for roadside services discovery. The protocol was implemented in congested highway scenario and extensive set of simulation experiments were performed to evaluate its performance under different parameters, e.g., Query Interval (QI), Query Attempts (QA), and Time to Live (TTL). / Vehicular Ad hoc Network (VANET) é um tipo especial de Mobile Ad hoc Network (MANET) e é uma tecnologia chave para apoiar os Sistemas Inteligentes de Transporte (ITSs). Ela desempenha um papel importante na implantação em grande escala das aplicações do tipo safety e non-safety. Dentre as aplicações non-safety, uma área importante e desafiadora é descoberta e divulgação de informação sobre serviços. Neste trabalho, nós adotamos a estratégia de beaconing e as comunicações veiculares oportunistas para resolver o problema da descoberta e divulgação de serviços ao longo de rodovias. Nossa abordagem oferece várias vantagens em relação aos métodos tradicionais usando painéis, painéis eletrônicos digitais e outdoors, por exemplo. Baixo custo, atinge um grande número de clientes em tempo real, maior controle sobre a campanha de propaganda, atualização dinâmica de conteúdo e descoberta de serviços antes de alcançar a região de negócio são algumas delas. Para a divulgação de serviços ao longo de rodovias, seguimos a estratégia de publicidade push-based e usamos somente comunicações do tipo Infrastructure-to-Vehicle (I2V). Por outro lado, para a descoberta destes serviços pelos motoristas, utilizamos a estratégia de publicidade pull-based e comunicações oportunistas do tipo Vehicle-to-Vehicle (V2V). A fim de contribuir para a campanha de propagandas, foi utilizado o mecanismo store-carry-and-response. Nossa primeira contribuição é o Extended Opportunistic Service Discovery Protocol (EOSDP). O EOSDP implementa e estende a versão original do Opportunistic Service Discovery Protocol (OSDP) via experimentos por simulação. Nós utilizamos os simuladores Simulation of Urban Mobility (SUMO), Objective Modular Network Testbed in C++ (OMNET++) e o Vehicles in network simulation (Veins). Nossa segunda contribuição é o Service Advertisement Protocol (SADP). SADP é um protocolo leve baseado na estratégia de beaconing para divulgação de serviços em VANETs. Ele não requer conexão com a Internet para anunciar os serviços nas margens das rodovias. Além disso, a modelagem do SADP é baseada no padrão de protocolos VANETs. O desempenho do SADP foi avaliado em um cenário de rodovia congestionada, com velocidades variáveis dos veículos e sob diferentes frequências de comunicação broadcast. Por fim, apresentamos o nosso último protocolo chamado Commercial Services Discovery Protocol (CSDP). Como o protocolo anterior, o CSDP é um protocolo leve para descoberta de serviços baseado em beaconing para VANETs. O CSDP depende somente de comunicações V2V oportunistas para a descoberta de serviços ao longo de rodovias. O protocolo foi implementado no cenário de uma rodovia congestionada e avaliado com um extenso conjunto de experimentos de simulação, sob diferentes parâmetros como, por exemplo, Query Interval (QI), Query Attempts (QA) e Time to Live (TTL).

Dans cette thèse, le compromis entre la consommation d'énergie et le délai dans les réseaux de capteurs sans fil est étudié en exploitant efficacement les liens non fiables. Nous proposons une métrique de l'efficacité énergétique et une métrique de délai moyenne qui sont combinés avec le modèle de lien radio à erreur. En utilisant ces deux métriques et un modèle réaliste de lien radio, nous déduisons la limite inférieure et le front de Pareto du compromis Energie-Délai sont calculés pour trois types de systèmes de communication: la communication multi-saut traditionnelle, la communication opportuniste et la communication coopérative MIMO (CMIMO) dans trois différents canaux: le canal a bruit additif blanc Gaussien, le canal a évanouissements rapides de Rayleigh et le canal a évanouissement de Rayleigh par blocs. Les expressions de ces limites faibles sont obtenues et vérifiées par des simulations bidimensionnelles de réseaux de capteurs distribués aléatoirement. Sur la base de l'expression de la borne inférieure du compromis Energie-Délai, un cadre multi-couche est fourni pour optimiser les paramètres des couches physique, MAC et routage sous contrainte de délai. Les résultats obtenus montrent que pour parvenir à une meilleure performance Energie-Délai, les mécanismes de communication suivants devraient être adoptés selon le type de canal : les communications multi-saut traditionnelles sont les plus performantes pour le canal à bruit additif blanc Gaussien, alors que les communications opportunistes le sont pour les canaux à évanouissements de Rayleigh par blocs et enfin le CMIMO pour les canaux à évanouissements rapides de Rayleigh.

The development of miniaturized radio and sensing technologies have enabled the deployment of large quantities of wireless sensors capable of forming multi-hop networks. Emerging applications of this technology such as surveillance and disaster monitoring have throughput and efficiency requirements not met by current routing algorithms. These requirements are also shared by ad-hoc networks. Early routing protocols for these wireless networks were based on algorithms designed for wired networks. Geographic routing (routing based on position), was proposed. These algorithms perform poorly since they do not account for the fading and interference effects of wireless channels. Recent protocols that have attempted to account for the wireless channel focus on single-hop situations and are not readily extensible to multi-hop networks. In this thesis we present a framework for routing based on a distributed routing decision and provide several example protocols. This framework provides a cross-layer design where the routing decision is decided through silent negotiation between candidate relays. We investigate the performance and parameters of this framework. We then present an example protocol using this framework which provides low-overhead opportunistic routing using cooperative diversity. This protocol uses the intrinsic characteristics of the wireless channel to achieve diversity while still maintaining relatively low overhead. An adaptation of the protocol for heterogeneous networks equipped with multiple antennas has also been discussed and evaluated through simulations. We also investigate another protocol based on this framework using the product of the instantaneous packet reception rate and the marginal progress towards the destination as a routing metric, offering enhanced throughput.

Diversity methods are used to improve the reliability of the communication between transmitter and receiver. These methods use redundancy to reduce the errors in the communication link. Apart from the conventional diversity methods, multiuser diversity has an aim of maximizing the sum capacity of a multi-user system. To benefit from multiuser diversity, the opportunistic scheduling method grants the channel access to the user which has the best channel quality among all users. Therefore, the cumulative sum of the information sent to all users, which is the sum capacity, is maximized in the long term. Although the opportunistic scheduling maximizes the sum capacity, it has some drawbacks such as the feedback load growing with the number of users and the problem of fairness for the users which may have lower channel quality than some other users. In this thesis, these two issues are investigated for the broadcast channels. Feedback quantization, which gives partial information on the channel state, is studied to mitigate the feedback load with a goal of little loss in the sum capacity. The thresholds for the finite feedback quantization are determined to provide fairness and to reduce the feedback load at the same time. To provide fairness, users are grouped into clusters and thresholds are optimized for each cluster. A method is proposed by extending the one given by Floren et. al. to solve the mentioned problems and the proposed method is compared with some other scheduling methods in the literature.

This dissertation considers the design, evaluation and optimization of algorithms/ techniques/ system parameters for distributed wireless networks specifically ad-hoc and cognitive wireless networks. In the first part of the dissertation, we consider ad-hoc networks using opportunistic carrier sense multiple access (CSMA) protocols. The key challenge in optimizing the performance of such systems is to find a good compromise among three interdependent quantities: the density and channel quality of the scheduled transmitters, and the resulting interference seen at receivers. We propose two new channel-aware slotted CSMA protocols and study the tradeoffs they achieve amongst these quantities. In particular, we show that when properly optimized these protocols offer substantial improvements relative to regular CSMA -- particularly when the density of nodes is moderate to high. Moreover, we show that a simple quantile based opportunistic CSMA protocol can achieve robust performance gains without requiring careful parameter optimization. In the second part of the dissertation, we study a cognitive wireless network where licensed (primary) users and unlicensed 'cognitive' (secondary) users coexist on shared spectrum. In this context, many system design parameters affect the joint performance, e.g., outage and capacity, seen by the two user types. We explore the performance dependencies between primary and secondary users from a spatial reuse perspective, in particular, in terms of the outage probability, node density and joint network capacity. From the design perspective the key system parameters determining the joint transmission capacity, and tradeoffs, are the detection radius (detection signal to interference and noise power ratio (SINR) threshold) and decoding SINR threshold. We show how the joint network capacity region can be optimized by varying these parameters. In the third part of the dissertation, we consider a cognitive network in a heterogeneous environment, including indoor and outdoor transmissions. We characterize the joint network capacity region under three different spectrum (white space) detection techniques which have different degrees of radio frequency (RF) - environment awareness. We show that cognitive devices relying only on the classical signal energy detection method perform poorly due to limitations on detecting primary transmitters in environments with indoor shadowing. This can be circumvented through direct use (e.g., database access) of location information on primary transmitters, or better yet, on that of primary receivers. We also show that if cognitive devices have positioning information, then the secondary network's capacity increases monotonically with increased indoor shadowing in the environment. This dissertation extends the recent efforts in using stochastic geometric models to capture large scale performance characteristics of wireless systems. It demonstrates the usefulness of these models towards understanding the impact of physical /medium access (MAC) layer parameters and how they might be optimized. / text

El presente trabajo presenta el estado del arte de las redes Ad Hoc y su posible aplicación a soluciones para rescatistas y de situación de emergencia por desastres naturales o de otra índole.

In the thesis, we address the fundamental problem of opportunistic spectrum access in a multi-channel communication system. Specifically, we consider a communication system in which a user has access to multiple channels, but is limited to sensing and transmitting only on one at a given time. We explore how the smart user should exploit past observations and the knowledge of the stochastic properties of these channels to maximize its transmission rate by switching channels opportunistically. Formally, we provide a generic analysis on the opportunistic spectrum access problem by casting the problem into the restless multi-armed bandit (RMAB) problem, one of the most well-known generalizations of the classic multi-armed bandit (MAB) problem, which is of fundamental importance in stochastic decision theory. Despite the significant research efforts in the field, the RMAB problem in its generic form still remains open. Until today, very little result is reported on the structure of the optimal policy. Obtaining the optimal policy for a general RMAB problem is often intractable due to the exponential computation complexity. Hence, a natural alternative is to seek a simple myopic policy maximizing the short-term reward. Therefore, we develop three axioms characterizing a family of functions which we refer to as regular functions, which are generic and practically important. We then establish the optimality of the myopic policy when the reward function can be expressed as a regular function and the discount factor is bounded by a closed-form threshold determined by the reward function. We also illustrate how the derived results, generic in nature, are applied to analyze a class of RMAB problems arising from multi-channel opportunistic access. Next, we further investigate the more challenging problem where the user has to decide the number of channels to sense in each slot in order to maximize its utility (e.g., throughput). After showing the exponential complexity of the problem, we develop a heuristic v-step look-ahead strategy. In the developed strategy, the parameter v allows to achieve a desired tradeoff between social efficiency and computation complexity. We demonstrate the benefits of the proposed strategy via numerical experiments on several typical settings.

Contamination of groundwater that is suitable for drinking is of growing concern as the water supply of South Africa is becomingincreasingly limited. This is especially the case in the North West province, with its semi – arid climate and variable rainfall patterns. The aim of the study was to evaluate the microbiological and physico – chemical qualities of groundwater obtained from selected DWA (Department of Water Affairs) monitoring boreholes in the Mooi River and Harts River catchment areas. Physico -chemical parameters included temperature, pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), sulphate and nitrate concentrations. Physical parameters were measured using a calibrated submerge-able multimeter and chemical parameters using specialised kits and a spectrophotometer. Microbiological parameters included heterotrophic plate counts and total and faecal coliform enumeration. Membrane filtration and culture based methods were followed for enumeration of bacteria. During the identification procedures multiplex PCR for E. coli identification and 16S rRNA gene sequencing for identification of heterotrophic plate count bacteria and amoeba resistant bacteria were used. For antibiotic resistance, the Kirby- Bauer (1996) disk diffusion method was used. During the warm and wet season high electrical conductivity and salinity were observed in the Trimpark (65.3 mS/m; 325 ppm), School (125.1 mS/m; 644 ppm), Warrenton (166.9 mS/m; 867 ppm) and Ganspan (83.3 mS/m; 421 ppm) boreholes. Warrenton borehole had a high sulphate level (450 mg/l) as well. High chemical oxygen demand was observed in the Blaauwbank (62 mg/l) and Warrenton (98.5 mg/l) boreholes. In the dry and cold season similar observations were made for the various boreholes. Electrical conductivity and salinity levels remained high for the Trimpark (70.1 mS/m; 427.5 ppm), School (127 mS/m; 645 ppm), Warrenton (173.3 mS/m; 896.5 ppm) and Ganspan (88.1 mS/m; 444.5 ppm) boreholes. Nitrate levels for the Trimpark (14.1 mg/l) and School (137 mg/l), as well as sulphate levels for the Warrenton (325 mg/l) borehole were also high. Total coliforms, faecal streptococci and HPC bacteria were enumerated from water samples from all boreholes, except Blaauwbank where no faecal streptococci were enumerated. Faecal coliforms were enumerated from 5 of the possible 7 boreholes during a warm and wet season (Trimpark – 42 cfu/100ml; School – 2 cfu/100ml; Cemetery – 175 cfu/100ml; Warrenton – 3.84 x 10³ cfu/100ml; Ganspan – 1.9 x 10³ cfu/100ml). Indicator bacteria (FC, TC, HPC) exceeded target water quality ranges (TWQR) for drinking water in each case. During the cold and dry sampling season, faecal coliforms were enumerated mainly from the Trimpark (11 cfu/100ml) borehole. Total coliforms, faecal streptococci and HPC bacteria were enumerated from all the boreholes, except for Blaauwbank that contained no faecal streptococci or total coliforms. Enumerated indicator bacteria levels again exceeded TWQR for domestic use. Total coliform counts for the Pad dam borehole, however, complied with TWQR for domestic use. Identified E. coli were resistant to Erythromycin, Cephalothin and Amoxicillin and susceptible to Ciprofloxacin. Escherichia coli isolated from the Mooi River catchment shared the same antibiotic resistance phenotype. The most abundant HPC bacterial genus identified was Pseudomonas spp. (7 isolates). Opportunistic pathogens isolated included Pseudomonas aeruginosa, Acinetobacter, Aeromonas, Alcaligenes, Flavobacterium, Bacillus cereus and Mycobacterium spp. Varying degrees of antibiotic resistance were observed. Generally, the same pattern between the same genera were observed. All HPC isolates were resistant to Cephalothin and Amoxicillin and a lower degree Erythromycin and Streptomycin. The most abundant amoeba resistant bacteria was identified as Pseudomonas spp. Other isolates included Alcaligenes faecalis and Ochrobactrum sp. and Achromobacter sp. All of these are opportunistic pathogens, except for Achromobacter. Resistance to more antibiotics (Streptomycin, Chloramphenicol, Cephalothin, and Amoxicillin) was observed in ARBs compared to HPC (Cephalothin, Amoxicillin) from bulk water from the same borehole. The water of all the aquifers sampled is of very poor physico - chemical or microbiological quality or both. Water may be used for irrigation or livestock watering only in the case where these boreholes comply with TWQR for said purposes. Results obtained indicate that the groundwater is faecally contaminated. Amongst the bacteria, opportunistic pathogens displaying various degrees of antibiotic resistance were frequently isolated. These results indicate health risks if untreated groundwater is consumed. Therefore groundwater needs to be treated before distribution especially if the water is for human consumption. / Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2013.