Description:
"This thesis investigates the influence of company and executive characteristics on strategic alliance formation (decision to form alliances, alliance type selection and choice of alliance partners) and performance evaluation of alliances, in the Australian tourism industry sector of travel. The significance of forming strategic alliances as a way of achieving 'harambe' is emphasised throughout this thesis. 'Harambe' is a ki-Swahili term meaning "to pull together, or to work together or to pull the same rope together at the same time" in harmony. The idea here is that companies pool their resources together through strategic alliances to be able to achieve their strategic goals and objectives. The research focuses on three travel sub-sectors - travel agencies, tour operators and wholesalers and how these sub-sectors relate with those of transport and accommodation." -
Description:
"This thesis investigates the influence of company and executive characteristics on strategic alliance formation (decision to form alliances, alliance type selection and choice of alliance partners) and performance evaluation of alliances, in the Australian tourism industry sector of travel. The significance of forming strategic alliances as a way of achieving 'harambe' is emphasised throughout this thesis. 'Harambe' is a ki-Swahili term meaning "to pull together, or to work together or to pull the same rope together at the same time" in harmony. The idea here is that companies pool their resources together through strategic alliances to be able to achieve their strategic goals and objectives. The research focuses on three travel sub-sectors - travel agencies, tour operators and wholesalers and how these sub-sectors relate with those of transport and accommodation." -
Description:
Attention-deficit/hyperactivity disorder (AD/HD) is marked by deficits in attention, hyperactivity and impulsivity (American Psychiatric Association, 1994). The current DSM-IV conceptualisation of AD/HD as comprising of separate, but related, Inattention (IA) and Hyperactivity/Impulsivity (H/I) dimensions have been supported in confirmatory factor analytic (CFA) studies. Despite being one of the most extensively studied childhood disorder, there is a lack of research on AD/HD in non-western populations. Research on AD/HD in Asian countries, particularly, is limited. To date, no study has comprehensively investigated the characteristics of AD/HD in a Malaysian sample. The current study had 4 major aims. The first aim of the study was to investigate how the IA and H/I symptoms groups vary by age, gender, and age by gender interaction. The second aim of the study was to obtain prevalence rates of DSM-IV AD/HD and the three subtypes (i.e., Predominantly Inattentive Type, AD/HD-IA; Predominantly Hyperactive/Impulsive Type, AD/HD-H/I; and Combined Type, AD/HD-C) within this population. This was examined for boys and girls separately, and together. The third aim of the study was to investigate the internal validity of DSM-IV AD/HD using single source confirmatory factor analysis (CFA), while the fourth aim of the study was to examine trait, source and error variance of the AD/HD symptoms using the CFA multitrait (IA and H/I) by multisource (parent and teacher) approach (CFA MT-MS). All the CFA and CFA MT-MS analyses were conducted separately for boys and girls and used scores recoded via the binary method, as opposed to the ordinal scoring method. The sample consisted of 934 Malaysian schoolchildren aged 6-12 years (436 boys: mean age 8.86 years; and 498 girls: mean age 9.02 years) [...] There was more source than trait variance for parent rated H/I and teacher rated IA for girls. Unique to the current study is the use of binary as opposed to ordinal data to run the CFA and MTMS analysis. The implications of the findings for the conceptualisation, assessment, treatment, psychometric properties of AD/HD rating scales and the recognition of AD/HD in the Malaysian population are discussed. Suggestions for future research are offered.
Description:
Attention-deficit/hyperactivity disorder (AD/HD) is marked by deficits in attention, hyperactivity and impulsivity (American Psychiatric Association, 1994). The current DSM-IV conceptualisation of AD/HD as comprising of separate, but related, Inattention (IA) and Hyperactivity/Impulsivity (H/I) dimensions have been supported in confirmatory factor analytic (CFA) studies. Despite being one of the most extensively studied childhood disorder, there is a lack of research on AD/HD in non-western populations. Research on AD/HD in Asian countries, particularly, is limited. To date, no study has comprehensively investigated the characteristics of AD/HD in a Malaysian sample. The current study had 4 major aims. The first aim of the study was to investigate how the IA and H/I symptoms groups vary by age, gender, and age by gender interaction. The second aim of the study was to obtain prevalence rates of DSM-IV AD/HD and the three subtypes (i.e., Predominantly Inattentive Type, AD/HD-IA; Predominantly Hyperactive/Impulsive Type, AD/HD-H/I; and Combined Type, AD/HD-C) within this population. This was examined for boys and girls separately, and together. The third aim of the study was to investigate the internal validity of DSM-IV AD/HD using single source confirmatory factor analysis (CFA), while the fourth aim of the study was to examine trait, source and error variance of the AD/HD symptoms using the CFA multitrait (IA and H/I) by multisource (parent and teacher) approach (CFA MT-MS). All the CFA and CFA MT-MS analyses were conducted separately for boys and girls and used scores recoded via the binary method, as opposed to the ordinal scoring method. The sample consisted of 934 Malaysian schoolchildren aged 6-12 years (436 boys: mean age 8.86 years; and 498 girls: mean age 9.02 years) [...] There was more source than trait variance for parent rated H/I and teacher rated IA for girls. Unique to the current study is the use of binary as opposed to ordinal data to run the CFA and MTMS analysis. The implications of the findings for the conceptualisation, assessment, treatment, psychometric properties of AD/HD rating scales and the recognition of AD/HD in the Malaysian population are discussed. Suggestions for future research are offered.
Anger : Specific cognitive and developmental factors : An investigation into the specific associations between anger, early maladaptive schemas and parenting
Description:
Harder kernels in barley are thought to be a factor affecting the modification of the endosperm during malting by restricting water and enzyme movement within the endosperm. The traditional method used in the malting industry to determine barley endosperm vitreousness is by visual assessment. Since this method is subjective, laborious and requires training, an alternative method is needed. Similarly, the causes and factors influencing kernel hardness are uncertain. The prime objectives of this study were: to identify an appropriate method to quantify kernel hardness; investigate the relationship between kernel hardness and endosperm composition; and to investigate the relationship between barley variety and environmental influences on endosperm composition in relation to the kernel hardness of malting barley.
Description:
Harder kernels in barley are thought to be a factor affecting the modification of the endosperm during malting by restricting water and enzyme movement within the endosperm. The traditional method used in the malting industry to determine barley endosperm vitreousness is by visual assessment. Since this method is subjective, laborious and requires training, an alternative method is needed. Similarly, the causes and factors influencing kernel hardness are uncertain. The prime objectives of this study were: to identify an appropriate method to quantify kernel hardness; investigate the relationship between kernel hardness and endosperm composition; and to investigate the relationship between barley variety and environmental influences on endosperm composition in relation to the kernel hardness of malting barley.
Description:
The sun-moths (family Castniidae) are a distinctive group of monocot-feeding diurnal Lepidoptera that contains a high proportion of threatened species worldwide. Seven of the eight Victorian Synemon species are considered as threatened. This study has determined through extensive fieldwork that most of these species are now restricted to very small remnants of their particular habitats. These findings have been integrated into a review of the current distribution, biology and habitat requirements of all the Victorian species. This has enabled recommendations for their long-term conservation and management to be made. Special attention was paid to the Pale Sun-moth (Synemon selene Klug, 1850) because it appeared to be nationally endangered and without a government strategy for its conservation. Also, there was strong circumstantial evidence of complete parthenogenesis within all of its Victorian populations. The Victorian occurrences are shown to be parthenogenetic, although specimens of both sexes are known from a ?now-extinct population near Two Wells, South Australia. It was also established that these parthenogenetic populations include five distinct morphs, two or three of which occur sympatrically at four localities in the Wimmera area. Parthenogenetic populations of these morphs cannot interbreed, this potentially restricting their genetic diversity. The extent of genetic diversity was examined with all parthenogenetic Victorian morphs of S. selene. DNA sequencing of 1515 bp of the COI gene revealed a maximum divergence level of 12 bp between some of the morphs and 1 to 2 bp within some morphs. This level of genetic diversity implies that these morphs have continued to evolve in the absence of males through time. This study has highlighted the special academic interest of S. selene and the urgent need for its adequate conservation. Some important directions for future research on the species are also discussed.
Description:
The sun-moths (family Castniidae) are a distinctive group of monocot-feeding diurnal Lepidoptera that contains a high proportion of threatened species worldwide. Seven of the eight Victorian Synemon species are considered as threatened. This study has determined through extensive fieldwork that most of these species are now restricted to very small remnants of their particular habitats. These findings have been integrated into a review of the current distribution, biology and habitat requirements of all the Victorian species. This has enabled recommendations for their long-term conservation and management to be made. Special attention was paid to the Pale Sun-moth (Synemon selene Klug, 1850) because it appeared to be nationally endangered and without a government strategy for its conservation. Also, there was strong circumstantial evidence of complete parthenogenesis within all of its Victorian populations. The Victorian occurrences are shown to be parthenogenetic, although specimens of both sexes are known from a ?now-extinct population near Two Wells, South Australia. It was also established that these parthenogenetic populations include five distinct morphs, two or three of which occur sympatrically at four localities in the Wimmera area. Parthenogenetic populations of these morphs cannot interbreed, this potentially restricting their genetic diversity. The extent of genetic diversity was examined with all parthenogenetic Victorian morphs of S. selene. DNA sequencing of 1515 bp of the COI gene revealed a maximum divergence level of 12 bp between some of the morphs and 1 to 2 bp within some morphs. This level of genetic diversity implies that these morphs have continued to evolve in the absence of males through time. This study has highlighted the special academic interest of S. selene and the urgent need for its adequate conservation. Some important directions for future research on the species are also discussed.
Description:
Work/life balance researchers have documented the low take-up rates of corporate work/life balance policies at the same time as there are reports of persistent work/life pressures. This research aims to provide more comprehensive explanations of the phenomenon of low policy take-up than those currently available in the work/life balance literature which focus on organisational and individual factors. The research project is based on a critical review of the work/life balance literature which focuses on organisational solutions and starts from the assumption that the organisational approach to researching and addressing work/life conflicts is inherently limited, mainly because it does not theorise gender as a social structure and does not take into consideration the social and political context in which work/life arrangements are negotiated but focuses, instead, on individual employees and organisations. I integrated my critical review of the organisational work/life balance literature with concepts in the feminist literature, most importantly the gendered public/private divide, to create an explicit ‘gender lens’ which guides the interpretations of my findings. I applied this gender lens to Habermas’ model of societal evolution to operationalise it as an analytical tool for this research. From this theoretical basis, I designed a comparative research project, using Australia and Sweden as country case studies, which compares the approaches to work/life balance in the two countries. The focus of the analysis is on parental leave as one important example of work/life balance policies. The data for this research includes the parental leave legislation, public documents released by governments and associated bodies as well as national surveys on the take-up of parental leave provisions in both countries. This material is analysed in the light of the conceptual framework. [...]
Description:
Work/life balance researchers have documented the low take-up rates of corporate work/life balance policies at the same time as there are reports of persistent work/life pressures. This research aims to provide more comprehensive explanations of the phenomenon of low policy take-up than those currently available in the work/life balance literature which focus on organisational and individual factors. The research project is based on a critical review of the work/life balance literature which focuses on organisational solutions and starts from the assumption that the organisational approach to researching and addressing work/life conflicts is inherently limited, mainly because it does not theorise gender as a social structure and does not take into consideration the social and political context in which work/life arrangements are negotiated but focuses, instead, on individual employees and organisations. I integrated my critical review of the organisational work/life balance literature with concepts in the feminist literature, most importantly the gendered public/private divide, to create an explicit ‘gender lens’ which guides the interpretations of my findings. I applied this gender lens to Habermas’ model of societal evolution to operationalise it as an analytical tool for this research. From this theoretical basis, I designed a comparative research project, using Australia and Sweden as country case studies, which compares the approaches to work/life balance in the two countries. The focus of the analysis is on parental leave as one important example of work/life balance policies. The data for this research includes the parental leave legislation, public documents released by governments and associated bodies as well as national surveys on the take-up of parental leave provisions in both countries. This material is analysed in the light of the conceptual framework. [...]
The causes and prevention of airline baggage handler back injuries : Safe designs required where behaviour and administrative solutions have had limited effect
Description:
"Back injuries have consistently been the most common types of injuries suffered by people at work. They have been a significant worker injury problem in most, if not all, industrialised countries for many years and manual handling has long been established as a significant task related back injury causal factor.[...] This research project established that the manufacturers of the jet airlines used by the airlines in this study had not previously been acquainted with the issue of baggage handler back injuries.[...] This study also canvassed the opinion of airline safety professionals and airline baggage handlers concerning baggage handling tasks and working environment related causal factors. [...] A major focus of this research project was also to measure the effect of ACE and Sliding Carpet, two commercially available retro-fit baggage systems, on the risk of back injuries to baggage handlers stacking baggage within Boeing B737 narrow-body aircraft."
Description:
"Back injuries have consistently been the most common types of injuries suffered by people at work. They have been a significant worker injury problem in most, if not all, industrialised countries for many years and manual handling has long been established as a significant task related back injury causal factor.[...] This research project established that the manufacturers of the jet airlines used by the airlines in this study had not previously been acquainted with the issue of baggage handler back injuries.[...] This study also canvassed the opinion of airline safety professionals and airline baggage handlers concerning baggage handling tasks and working environment related causal factors. [...] A major focus of this research project was also to measure the effect of ACE and Sliding Carpet, two commercially available retro-fit baggage systems, on the risk of back injuries to baggage handlers stacking baggage within Boeing B737 narrow-body aircraft."
Description:
"Arsenic is a common soil contaminant in Australia and worldwide. There is a need to find safe, effective and economic methods to deal with this problem. The soils used in this research were collected from central Victoria. They were contaminated with arsenic by historic gold mining activity or by past sheep dipping practices. This research investigated ten different leaching agents for their effects on three different arsenic contaminated soils. [...] Electrokinetic experiments were conducted on three arsenic contaminated soils. [...] The arsenic in these soils appears to be relatively stable and immobile under oxidising conditions. The soils had a high iron content which assists in the stabilisation of arsenic. This is beneficial with respect to the environmental impact of the arsenic contamination, however, it remains an obstacle to low cost electrokinetic remediation."
Description:
"Arsenic is a common soil contaminant in Australia and worldwide. There is a need to find safe, effective and economic methods to deal with this problem. The soils used in this research were collected from central Victoria. They were contaminated with arsenic by historic gold mining activity or by past sheep dipping practices. This research investigated ten different leaching agents for their effects on three different arsenic contaminated soils. [...] Electrokinetic experiments were conducted on three arsenic contaminated soils. [...] The arsenic in these soils appears to be relatively stable and immobile under oxidising conditions. The soils had a high iron content which assists in the stabilisation of arsenic. This is beneficial with respect to the environmental impact of the arsenic contamination, however, it remains an obstacle to low cost electrokinetic remediation."
Description:
The thesis analyses the delivery of the Community Aged Care Packages Program, revealing the flaws in the program’s design and the consequences of this programmatic design for service providers in rural Victoria
Description:
The thesis analyses the delivery of the Community Aged Care Packages Program, revealing the flaws in the program’s design and the consequences of this programmatic design for service providers in rural Victoria
Description:
"The goal of this thesis was to evaluate high speed steel for use in the construction of sheep shearing combs, to determine if its use can be justified on a performance basis."
Description:
"The goal of this thesis was to evaluate high speed steel for use in the construction of sheep shearing combs, to determine if its use can be justified on a performance basis."
Description:
The purpose of this thesis is to develop some new algorithms based on optimization techniques for solving some problems in some areas of telecommunications and the Internet. There are two main parts to this thesis. In the first part we discuss optimization based stochastic and queueing models in telecommunications network corrective maintenance. In the second part we develop optimization based clustering (OBC) algorithms for network evolution and multicast routing. The most typical scenario encountered during mathematical optimization modelling in telecommunications, for example, is to minimize the cost of establishment and maintenance of the networks subject to the performance constraints of the networks and the reliability constraints of the networks as well. Most of these optimization problems are global optimization, that is, they have many local minima and most of these local minima do not provide any useful information for solving these problems. Therefore, the development of effective methods for solving such global optimization problems is important. To run the telecommunications networks with cost-effective network maintenance,we need to establish a practical maintenance model and optimize it. In the first part of the thesis, we solve a known stochastic programming maintenance optimization model with a direct method and then develop some new models. After that we introduce queue programming models in telecommunications network maintenance optimization. The ideas of profit, loss, and penalty will help telecommunications companies have a good view of their maintenance policies and help them improve their service. In the second part of this thesis we propose the use of optimization based clustering (OBC) algorithms to determine level-constrained hierarchical trees for network evolution and multicast routing. This problem is formulated as an optimization problem with a non-smooth, non-convex objective function. Different algorithms are examined for solving this problem. Results of numerical experiments using some artifiicial and real-world databases are reported.
Description:
The purpose of this thesis is to develop some new algorithms based on optimization techniques for solving some problems in some areas of telecommunications and the Internet. There are two main parts to this thesis. In the first part we discuss optimization based stochastic and queueing models in telecommunications network corrective maintenance. In the second part we develop optimization based clustering (OBC) algorithms for network evolution and multicast routing. The most typical scenario encountered during mathematical optimization modelling in telecommunications, for example, is to minimize the cost of establishment and maintenance of the networks subject to the performance constraints of the networks and the reliability constraints of the networks as well. Most of these optimization problems are global optimization, that is, they have many local minima and most of these local minima do not provide any useful information for solving these problems. Therefore, the development of effective methods for solving such global optimization problems is important. To run the telecommunications networks with cost-effective network maintenance,we need to establish a practical maintenance model and optimize it. In the first part of the thesis, we solve a known stochastic programming maintenance optimization model with a direct method and then develop some new models. After that we introduce queue programming models in telecommunications network maintenance optimization. The ideas of profit, loss, and penalty will help telecommunications companies have a good view of their maintenance policies and help them improve their service. In the second part of this thesis we propose the use of optimization based clustering (OBC) algorithms to determine level-constrained hierarchical trees for network evolution and multicast routing. This problem is formulated as an optimization problem with a non-smooth, non-convex objective function. Different algorithms are examined for solving this problem. Results of numerical experiments using some artifiicial and real-world databases are reported.
Development of a model of mental health vulnerability for young men living in rural and regional areas : An investigation of the roles of sense of belonging and employment status
Description:
"This thesis proposes a Kristevan reading of the fantasy novels of Stephen Donaldson, with particular attention given to Kristeva's concepts of the symbolic order, the semiotic 'chora', abjection, the imaginery father and the thetic. It also identifies and comments on shortcomings in Kristevan theory. Donaldson's fantasies are dominated by male protagonists, one of whom is a leper while the others are rapists or murderers or else engaged in some form of violence or sexual perversion. This thesis not only offers an interpretation for this representation of disease and gross physical abuse, but also looks to the implication such corporeality brings to bear on the amatory relationships that the novels attempt to establish. "The thesis is organized into three broad sections. The first considers the ways in which the concept of the mother manifests in Donaldson's text and how the male protagonists respond to the maternal dynamic established in these books. [...] The second section of the thesis examines the role played by Donaldson's father figures. [...] The third section of [the] thesis examines the consequences of this male vulnerability with regard to its central characters who oscillate between symbolic standing and semiotic sprawl."
Description:
This thesis began with a research project on suicide that was abandoned after many hurdles were encountered in terms of reaching participants and after various applications to ethics committees. The ultimate research question was then recast as ‘Do Human Research Ethics Committees influence the conduct of suicide research in Australia?’ The conceptual framework for setting up the research was derived from literature on Critical Theory, Feminism and Weberian concepts of power and rationality. Subsidiary questions were then derived from this literature and the starting exemplar case of my own research attempts. These considered whether suicide research was problematic for ethics committees, the nature of the experiences of ethics committee members in making decisions regarding suicide research and whether the influences of disciplinary background, patriarchal medical dominance and pro-positivism were evident. In addition, questions were raised about whether and how other researchers who sought approval to conduct research into suicide-related issues were appraised. [...]
Description:
This thesis began with a research project on suicide that was abandoned after many hurdles were encountered in terms of reaching participants and after various applications to ethics committees. The ultimate research question was then recast as ‘Do Human Research Ethics Committees influence the conduct of suicide research in Australia?’ The conceptual framework for setting up the research was derived from literature on Critical Theory, Feminism and Weberian concepts of power and rationality. Subsidiary questions were then derived from this literature and the starting exemplar case of my own research attempts. These considered whether suicide research was problematic for ethics committees, the nature of the experiences of ethics committee members in making decisions regarding suicide research and whether the influences of disciplinary background, patriarchal medical dominance and pro-positivism were evident. In addition, questions were raised about whether and how other researchers who sought approval to conduct research into suicide-related issues were appraised. [...]
Description:
Arid areas are often overgrazed and dysfunctional with poor recruitment of desirable species, diminished control over resources and altered soil properties. Restoration ecology re-establishes these valued processes. State-and-transition models summarise knowledge of vegetation dynamics and tools for restoration, and encourage the incorporation of new information. The model developed here for semi-arid woodlands of north-west Victoria highlighted the unknown cause of observed, natural recruitment and the need for a technique, other than direct seeding and handplanting, for enhancing the recruitment of desirable species. I pursued these knowledge gaps for two dominant, woodland trees: Allocasuarina luehmannii and Casuarina pauper. Natural recruitment of juvenile C. pauper was found to be limited and primarily from root suckers. Extensive recruitment of A. luehmannii was shown to be mostly seedlings established following substantial reductions in grazing pressure since 1996. Seedlings were associated with areas devoid of ground flora near a female tree. The importance of competition between seedlings and ground flora, spatial variation in soil moisture and individual variation in the quantity of seed produced deserves further investigation to enhance future restoration success. Root suckers of both C. pauper and A. luehmannii can be artificially initiated, albeit in low numbers and this was found to be a feasible, new tool for restoration. Suckers are preceded by the growth of callus tissue on exposed or damaged, living, shallow roots. Both male and female trees can produce suckers and spring treatments may be more successful. Genetic fingerprinting of mature A. luehmannii and C. pauper trees in six populations did not identify any clonal individuals indicating that recruitment in the past has been from seedlings. Despite this, the high level of gene flow suggests that the impact of introducing small numbers of root suckers into existing populations is unlikely to impact negatively on the population genetics of these species.
Description:
Arid areas are often overgrazed and dysfunctional with poor recruitment of desirable species, diminished control over resources and altered soil properties. Restoration ecology re-establishes these valued processes. State-and-transition models summarise knowledge of vegetation dynamics and tools for restoration, and encourage the incorporation of new information. The model developed here for semi-arid woodlands of north-west Victoria highlighted the unknown cause of observed, natural recruitment and the need for a technique, other than direct seeding and handplanting, for enhancing the recruitment of desirable species. I pursued these knowledge gaps for two dominant, woodland trees: Allocasuarina luehmannii and Casuarina pauper. Natural recruitment of juvenile C. pauper was found to be limited and primarily from root suckers. Extensive recruitment of A. luehmannii was shown to be mostly seedlings established following substantial reductions in grazing pressure since 1996. Seedlings were associated with areas devoid of ground flora near a female tree. The importance of competition between seedlings and ground flora, spatial variation in soil moisture and individual variation in the quantity of seed produced deserves further investigation to enhance future restoration success. Root suckers of both C. pauper and A. luehmannii can be artificially initiated, albeit in low numbers and this was found to be a feasible, new tool for restoration. Suckers are preceded by the growth of callus tissue on exposed or damaged, living, shallow roots. Both male and female trees can produce suckers and spring treatments may be more successful. Genetic fingerprinting of mature A. luehmannii and C. pauper trees in six populations did not identify any clonal individuals indicating that recruitment in the past has been from seedlings. Despite this, the high level of gene flow suggests that the impact of introducing small numbers of root suckers into existing populations is unlikely to impact negatively on the population genetics of these species.
Description:
The aim of the present study was to gain an understanding of the experience of treatment via an Internet-based cognitive behavioural self-help protocol for social anxiety disorder. Participants were four adults, aged between 22-46 years, who fulfilled DSM-IV-TR crriteria for a diagnosis of social anxiety disorder.
Description:
Wireless Local Area Networks (WLANs) have become a major success in telecommunications during the last few years, due to advantages such as mobility, flexibility, and easier maintenance. A device called an access point (AP) acts as a base station in WLAN for connecting a group of users to the network via radio signal. During the planning of such a network an important problem is to determine the optimal number of these devices and their placement/distribution so that coverage, capacity, and physical security are maximised at minimum cost. In this thesis we are using continuous optimisation techniques to optimise the number of APs and their distribution while cost of deployment is reduced and physical security of the network is enhanced. To find the number and placement of APs, we developed a multi-objective functions model based on path losses and power for free space environments. The two functions in the models are combined by using a balancing parameter. Since it is recognised that some of the objectives can be handled one at a time, in another approach, we followed a step-by-step procedure. We start with a novel optimisation model based on path losses for indoor environments including obstacles. Cost of deployment is saved by finding the minimum number of APs ensuring that the path loss at each test point/receiver is below the given maximum path loss. Next, the physical security of the network is enhanced by placing the APs far from places accessible to unauthorised users to reduce the risk of intrusion into the network. This is achieved in the framework of the model by introducing potential unauthorised users in unauthorised areas for whom coverage is minimised. Due to the presence of obstacles in indoor buildings, the path loss function is discontinuous. Therefore, the objective functions are very complicated and most of the existing optimisation algorithms cannot be applied to solve the problem. We use a global optimisation algorithm that is not used by other researchers to solve the same problem. To validate the accuracy of the optimisation model and performance of the numerical methods, we run tests on several indoor buildings and use wide range of WLAN parameters. The results demonstrate the quality of our model and algorithm. Based on the proposed model and algorithm, we developed a software to assist the network designers in planning wireless LANs.
Description:
Wireless Local Area Networks (WLANs) have become a major success in telecommunications during the last few years, due to advantages such as mobility, flexibility, and easier maintenance. A device called an access point (AP) acts as a base station in WLAN for connecting a group of users to the network via radio signal. During the planning of such a network an important problem is to determine the optimal number of these devices and their placement/distribution so that coverage, capacity, and physical security are maximised at minimum cost. In this thesis we are using continuous optimisation techniques to optimise the number of APs and their distribution while cost of deployment is reduced and physical security of the network is enhanced. To find the number and placement of APs, we developed a multi-objective functions model based on path losses and power for free space environments. The two functions in the models are combined by using a balancing parameter. Since it is recognised that some of the objectives can be handled one at a time, in another approach, we followed a step-by-step procedure. We start with a novel optimisation model based on path losses for indoor environments including obstacles. Cost of deployment is saved by finding the minimum number of APs ensuring that the path loss at each test point/receiver is below the given maximum path loss. Next, the physical security of the network is enhanced by placing the APs far from places accessible to unauthorised users to reduce the risk of intrusion into the network. This is achieved in the framework of the model by introducing potential unauthorised users in unauthorised areas for whom coverage is minimised. Due to the presence of obstacles in indoor buildings, the path loss function is discontinuous. Therefore, the objective functions are very complicated and most of the existing optimisation algorithms cannot be applied to solve the problem. We use a global optimisation algorithm that is not used by other researchers to solve the same problem. To validate the accuracy of the optimisation model and performance of the numerical methods, we run tests on several indoor buildings and use wide range of WLAN parameters. The results demonstrate the quality of our model and algorithm. Based on the proposed model and algorithm, we developed a software to assist the network designers in planning wireless LANs.