The purpose of this thesis is to create the foundation for a rating system that provides a consistent standard of measurement for sustainable set design, encompassing the entire process from concept, construction, and use, to deconstruction and waste management. / text

Ecological travel (ecotourism) is the “next big thing”. To experience nature up close and personal is to backpack off the beaten track and these days this is the “hippest” way to travel. Ecotourism is seen as the most excelling fragment of tourism and The United Nations World Tourism Organisation (UNWTO) views tourism in an unspoilt natural area (ecotourism) as the fastest growing concept of the tourism industry. Ecotourism has evolved into speciality travel; including an assorted – and often confusing – collection of events and tourism types, for example bird watching, methodical study, photography, diving and trekking. Ecotourism takes place in unspoilt natural areas, lodges and conservation areas such as national parks. South African National Parks, (SANParks), whom manages a system of parks, and signifies the indigenous fauna & flora, landscapes and associated cultural heritage of the country. National parks offers facilities for overnight tourist, with a range of accommodation, in arid, coastal, mountain and bush veld habitats. A variety of incomparable adventure tourism opportunities, for example game viewing, bush walks, canoeing and exposure to cultural and historical experiences are offered by these national parks. SANParks’ objectives are the insurance of protection, conservation and management of the protected areas for the purposes they were declared. The key aspect of SANParks’ management operations is ecotourism. The three areas that the management of parks cover are general management which include finance and marketing; conservation management which consists of wildlife counting, sales of wildlife, environment etc. and ecotourism management which includes aspects such as camps, accommodation, game drives and picnic areas. Because ecotourism as an important aspect of park management and is one of SANParks’ core pillars, the main concern is which strategies and policies are in place in order to provide tourists with an ecotourism experience within South African National Parks? Tourism products (especially accommodation products) need to recognize that customers (tourists) have certain expectations and these expectations must be met. One way in meeting these expectations is to adhere to tourists’ perceptions and satisfaction as well as to provide a quality service. It is also seen as one of the most important influences on productivity and profit of a tourism organisation. One approach to obtain customer satisfaction and meeting expectations is to implement a grading/rating system. When managers and owners of accommodation and tourism products want to convince tourists of the quality of the organisation or tourism product that is being presented, a classification or rating system plays an important role to communicate this vital issue. South Africa has various rating systems / schemes, however there are no acknowledged rating systems for ecotourism products in South Africa National Parks. The shortcomings of these current rating systems are that they rate mostly the hospitality and accommodation sectors. These criteria’s tend to focus on the following: building exteriors, bedrooms, bathrooms, public area, general facilities, general services, housekeeping services, additional facilities and responsible environmental and business practices. None of these schemes focus primarily on ecotourism principles. These systems need to be adapted for nature/wildlife products and the problem that this study will address is to develop an ecotourism rating system for South African National Parks. It is essential to have a rating system in place to compete in the global world where ecotourism and green aspects are important and to deliver a valuable service. Therefore the problem that this research will addresses, is to develop an ecotourism rating system for South Africa National Parks. The research approach used in this study included quantitative methodologies. An explorative research approach was followed through an online questionnaire with the aim of determining the perceptions of visitors about the perceptions of respondents regarding the importance of specific ecotourism principles. These constructs were determined through a literature review. The sources consulted included the following: De Witt, 2011; Du Plessis, 2010; Geldenhuys, 2009:5; Saayman, 2009:70; Fennell, 2008:23; Blamey, 2001:12; Eagles, 1996; Dingwall and Gordon, 1996. The questionnaire was distributed electronically on the SANParks’ website. Data collection took place during April 2013. A total of 308 responses were received during the period of data collection. The results of the empirical quantitative data was analysed by the Statistical Consultation Services at the North-West University by means of the SPSS (Statistical Package for Social Sciences) software programme. The statistical methods utilised included descriptive statistics and causal research. The descriptive statistics includes the demographic profile of respondents, the principles of ecotourism, the factor analysis and the factor correlation matrix. The causal research includes the t-test and the analysis of variance (ANOVA). The results of the descriptive data indicated that the language most spoken by the respondents was primarily English followed by Afrikaans. The greater number of respondents was married and live in Gauteng. They were well educated with a diploma or degree. Most of the respondents were Wild Card holders and supports conservation organisations, such as Rhino Conservation, followed by SA Wildlife, SANParks Honorary Rangers, Green Peace, UNITE against poaching and World Wide Fund for Nature. Respondents’ understanding of responsible ecotourism is conserving and protecting nature, has a low impact on the environment and has an educational travel experience in any environment. The key principles of ecotourism, namely conservation of nature, conservation of culture, community involvement, environmental education, tourist satisfaction, responsible tourism practices, environmental education, tourist satisfaction, responsible tourism practices, role players participating in ecotourism – the tourist and accommodation and were rated based on a five point Likert scale. The principles that were rated with the highest mean values included: water sources are protected (4.83); tourists are told not to touch or disturb birds and animals (4.76); correct disposal of waste, including cigarette butts, into allocated waste bins is encouraged (4.73); dripping taps are fixed immediately (4.70) and noise is limited in natural areas (4.70). The exploratory factor analysis was conducted on the principles identified, they were as follows: Conservation of nature had five factors namely, Conservation; Controlled development; Environmental friendly; Alien plants; Water saving measurements. Conservation of culture had two factors namely, Local community involvement; Benefit for community. Community involvement had two factors namely, Benefits; Education for community. Environmental education had only one factor namely, learning experiences. Tourist satisfaction also had one factor namely, Tourist satisfaction. Responsible tourism practices had three factors namely, recycling and environmental friendly practices; Interaction with nature; Responsible practices. Tourist participation in ecotourism had one factor namely, Informed tourist. Accommodation had three factors namely, Eco-friendly practices and development; Touch the earth lightly; Environmental friendly accommodation. Group statistics namely t-tests and ANOVA’s were performed to determine whether there were any significant differences between the factors identified from the ecotourism principles. The ttest was used to compare the socio-demographic aspects, namely home language (English and Afrikaans) with all the ecotourism principles. The t-test was used to compare behavioural aspects, namely Wild Card holders (Yes and No) with all the ecotourism principles. This were done to determine if the respondents’ opinions differ about principles in terms of Wild Card holders or non- Wild Card holders. The ANOVA was tested for socio-demographic aspects of respondents namely, marital status. The ANOVA was tested for socio-demographic aspects of respondents namely, level of education. The research made the following contributions to the field of ecotourism. These contributions are made in three categories namely, literature, methodology and practical contributions: * It is the first time that literature about ecotourism are combined to identify principles and constructs. All rating criteria was investigated to do this. * First time that different rating systems regarding ecotourism was identified, analysed and compared to each other. * Added to the literature on future trends of ecotourism which will assist in the planning and development of ecotourism products as well as rating systems. * The rating system can assist in future ecotourism development in protected areas as the most important principle for ecotourism have been identified. * The research contribute to more environment friendly development of ecotourism accommodation products * It is the first time that all relevant aspects of ecotourism was identified and developed into questionnaire that test ecotourism rating constructs and principles. * The research also contribute to the fact that one knows what are the ecotourism constructs that are seen as important by the visitor to national parks. The empirical results also determined statistical differences of the constructs and principles regarding socio-demographic and behavioural aspects of the visitors to national parks in South Africa. * This was the first time that a specific rating system was developed for South African National Parks. * This rating system can also be adapted to other conservation areas such as game reserves and game farms. / PhD (Tourism Management), North-West University, Potchefstroom Campus, 2015

Ecological travel (ecotourism) is the “next big thing”. To experience nature up close and personal is to backpack off the beaten track and these days this is the “hippest” way to travel. Ecotourism is seen as the most excelling fragment of tourism and The United Nations World Tourism Organisation (UNWTO) views tourism in an unspoilt natural area (ecotourism) as the fastest growing concept of the tourism industry. Ecotourism has evolved into speciality travel; including an assorted – and often confusing – collection of events and tourism types, for example bird watching, methodical study, photography, diving and trekking. Ecotourism takes place in unspoilt natural areas, lodges and conservation areas such as national parks. South African National Parks, (SANParks), whom manages a system of parks, and signifies the indigenous fauna & flora, landscapes and associated cultural heritage of the country. National parks offers facilities for overnight tourist, with a range of accommodation, in arid, coastal, mountain and bush veld habitats. A variety of incomparable adventure tourism opportunities, for example game viewing, bush walks, canoeing and exposure to cultural and historical experiences are offered by these national parks. SANParks’ objectives are the insurance of protection, conservation and management of the protected areas for the purposes they were declared. The key aspect of SANParks’ management operations is ecotourism. The three areas that the management of parks cover are general management which include finance and marketing; conservation management which consists of wildlife counting, sales of wildlife, environment etc. and ecotourism management which includes aspects such as camps, accommodation, game drives and picnic areas. Because ecotourism as an important aspect of park management and is one of SANParks’ core pillars, the main concern is which strategies and policies are in place in order to provide tourists with an ecotourism experience within South African National Parks? Tourism products (especially accommodation products) need to recognize that customers (tourists) have certain expectations and these expectations must be met. One way in meeting these expectations is to adhere to tourists’ perceptions and satisfaction as well as to provide a quality service. It is also seen as one of the most important influences on productivity and profit of a tourism organisation. One approach to obtain customer satisfaction and meeting expectations is to implement a grading/rating system. When managers and owners of accommodation and tourism products want to convince tourists of the quality of the organisation or tourism product that is being presented, a classification or rating system plays an important role to communicate this vital issue. South Africa has various rating systems / schemes, however there are no acknowledged rating systems for ecotourism products in South Africa National Parks. The shortcomings of these current rating systems are that they rate mostly the hospitality and accommodation sectors. These criteria’s tend to focus on the following: building exteriors, bedrooms, bathrooms, public area, general facilities, general services, housekeeping services, additional facilities and responsible environmental and business practices. None of these schemes focus primarily on ecotourism principles. These systems need to be adapted for nature/wildlife products and the problem that this study will address is to develop an ecotourism rating system for South African National Parks. It is essential to have a rating system in place to compete in the global world where ecotourism and green aspects are important and to deliver a valuable service. Therefore the problem that this research will addresses, is to develop an ecotourism rating system for South Africa National Parks. The research approach used in this study included quantitative methodologies. An explorative research approach was followed through an online questionnaire with the aim of determining the perceptions of visitors about the perceptions of respondents regarding the importance of specific ecotourism principles. These constructs were determined through a literature review. The sources consulted included the following: De Witt, 2011; Du Plessis, 2010; Geldenhuys, 2009:5; Saayman, 2009:70; Fennell, 2008:23; Blamey, 2001:12; Eagles, 1996; Dingwall and Gordon, 1996. The questionnaire was distributed electronically on the SANParks’ website. Data collection took place during April 2013. A total of 308 responses were received during the period of data collection. The results of the empirical quantitative data was analysed by the Statistical Consultation Services at the North-West University by means of the SPSS (Statistical Package for Social Sciences) software programme. The statistical methods utilised included descriptive statistics and causal research. The descriptive statistics includes the demographic profile of respondents, the principles of ecotourism, the factor analysis and the factor correlation matrix. The causal research includes the t-test and the analysis of variance (ANOVA). The results of the descriptive data indicated that the language most spoken by the respondents was primarily English followed by Afrikaans. The greater number of respondents was married and live in Gauteng. They were well educated with a diploma or degree. Most of the respondents were Wild Card holders and supports conservation organisations, such as Rhino Conservation, followed by SA Wildlife, SANParks Honorary Rangers, Green Peace, UNITE against poaching and World Wide Fund for Nature. Respondents’ understanding of responsible ecotourism is conserving and protecting nature, has a low impact on the environment and has an educational travel experience in any environment. The key principles of ecotourism, namely conservation of nature, conservation of culture, community involvement, environmental education, tourist satisfaction, responsible tourism practices, environmental education, tourist satisfaction, responsible tourism practices, role players participating in ecotourism – the tourist and accommodation and were rated based on a five point Likert scale. The principles that were rated with the highest mean values included: water sources are protected (4.83); tourists are told not to touch or disturb birds and animals (4.76); correct disposal of waste, including cigarette butts, into allocated waste bins is encouraged (4.73); dripping taps are fixed immediately (4.70) and noise is limited in natural areas (4.70). The exploratory factor analysis was conducted on the principles identified, they were as follows: Conservation of nature had five factors namely, Conservation; Controlled development; Environmental friendly; Alien plants; Water saving measurements. Conservation of culture had two factors namely, Local community involvement; Benefit for community. Community involvement had two factors namely, Benefits; Education for community. Environmental education had only one factor namely, learning experiences. Tourist satisfaction also had one factor namely, Tourist satisfaction. Responsible tourism practices had three factors namely, recycling and environmental friendly practices; Interaction with nature; Responsible practices. Tourist participation in ecotourism had one factor namely, Informed tourist. Accommodation had three factors namely, Eco-friendly practices and development; Touch the earth lightly; Environmental friendly accommodation. Group statistics namely t-tests and ANOVA’s were performed to determine whether there were any significant differences between the factors identified from the ecotourism principles. The ttest was used to compare the socio-demographic aspects, namely home language (English and Afrikaans) with all the ecotourism principles. The t-test was used to compare behavioural aspects, namely Wild Card holders (Yes and No) with all the ecotourism principles. This were done to determine if the respondents’ opinions differ about principles in terms of Wild Card holders or non- Wild Card holders. The ANOVA was tested for socio-demographic aspects of respondents namely, marital status. The ANOVA was tested for socio-demographic aspects of respondents namely, level of education. The research made the following contributions to the field of ecotourism. These contributions are made in three categories namely, literature, methodology and practical contributions: * It is the first time that literature about ecotourism are combined to identify principles and constructs. All rating criteria was investigated to do this. * First time that different rating systems regarding ecotourism was identified, analysed and compared to each other. * Added to the literature on future trends of ecotourism which will assist in the planning and development of ecotourism products as well as rating systems. * The rating system can assist in future ecotourism development in protected areas as the most important principle for ecotourism have been identified. * The research contribute to more environment friendly development of ecotourism accommodation products * It is the first time that all relevant aspects of ecotourism was identified and developed into questionnaire that test ecotourism rating constructs and principles. * The research also contribute to the fact that one knows what are the ecotourism constructs that are seen as important by the visitor to national parks. The empirical results also determined statistical differences of the constructs and principles regarding socio-demographic and behavioural aspects of the visitors to national parks in South Africa. * This was the first time that a specific rating system was developed for South African National Parks. * This rating system can also be adapted to other conservation areas such as game reserves and game farms. / PhD (Tourism Management), North-West University, Potchefstroom Campus, 2015

When working on United States Green Building Council’s (USGBC) Leadership in Energy and Environmental Design LEED projects, architects, designers, and engineers involved in a sustainable design project often require information and tools beyond energy simulation software. They may require resources (tools) to support their decisions and to assess the risk involved in decision making. This research has presented a framework that links building performance assessment tools with the LEED rating system. It aims at bridging a gap between Architects, engineers, contractors, facility managers and LEED professionals. This work provides information about performance tools that can be used for different phases during design, construction and operation of a LEED rated building. A simple logic of the transitive property of equality i.e. if a = b, b = c then a = c was used to link the LEED credits requiring decision support with the tools that have capabilities to achieve it. This research presents a 3-dimensional matrix of "Right tool for right job at right time" by linking LEED credits, software tools and phases of building design, construction and operation. Overall the findings of the research demonstrated that the framework developed can be used for achieving 21 percent of total possible LEED 3.0 credits by providing about 36 percent of total possible points.

Leadership in Energy and Environmental Design (LEED) is one of the environmental assessment tools available to gauge buildings. This rating system is a voluntary system which does not include financial aspects in the evaluation framework. This poses a challenge for encouraging land development projects, since developers consider financial or economic return as a crucial factor before building a project. It becomes essential to know if market really accepts the economic worth of LEED ratings. This research attempted to find out relationship between economic worth of a land and parameters (measurements), which are essential to earn LEED sustainable rating for public transportation access. To find out this relationship and to recognize power of the LEED measurements to predict the appraised value of a land (dollars per square foot) various statistical models were used and predictive equations produced. The observational units were properties in Harris County, Texas that were unimproved and had zero improvement value. The dependent variable was unit value of the property measured in dollars per square foot. The independent variables were measurements that are required for a parcel to earn LEED sustainable site rating for public transportation access and the area of parcel. Data regarding appraised values and land area were acquired from the Harris County Appraisal District and transportation data was obtained from Houston- Galveston Area Council. Multiple regression analysis was used to analyze different models and to develop predictive equations. Findings suggest that LEED green building rating system influences the appraised value, dollars per square foot, of properties. It further implies that market considers the economic effect of the LEED rating system even if this assessment method does not explicitly include financial aspects in the evaluation framework. Findings of this research also suggest that a sustainable feature of a site is related to the economic worth of a related land development project. This will provide encouragement for new sustainable land development projects. This will provide an economic incentive to the owners and developers. Developers will get encouragement to select a site located closer to mass transit networks.

The rapid growth of online games enables firms to charge players for virtual goods they sell for use within their online game environments. Determining prices for such virtual goods is inherently challenging due to the absence of explicit supply curve as the marginal cost of producing additional virtual goods is negligible. Utilizing sales data, we study daily revenue of a firm operating a virtual world and selling cards. Explicitly, we analyze the impact of new product releases on revenue using ARIMA with intervention model. We show that during initial days after a new product release, the firm's daily revenue significantly increases. Using a quality measure, based on the Elo rating method, we can determine the relative good prices based on good usage. Applying this method we show that the rating of a product can be a good proxy for units sold. We conclude that our quality-based measure can be adopted for pricing other virtual goods.

Reputation systems have the potential of improving the quality of on-line markets by identifying fraudulent users and subsequently dealing with these users can be prevented. The behaviour of participants involved in e-commerce can be recorded and then this information made available to potential transaction partners to make decisions to choose a suitable counterpart. Unfortunately current reputation systems suffer from various vulnerabilities. Solutions for many of these problems will be discussed. One of the major threats is that of unfair feedback. A large number of negative or positive feedbacks could be submitted to a particular user with the aim to either downgrade or upgrade the user's reputation. As a result the produced reputation does not reflect the user's true trustworthiness. To overcome this threat a variation of Bayesian Reputation system is proposed. The proposed scheme is based on the subjective logic framework proposed Josang et al. [65]. The impact of unfair feedback is countered through some systematic approaches proposed in the scheme. Lack of anonymity for participants leads to reluctance to provide negative feedback. A novel solution for anonymity of feedback providers is proposed to allow participants to provide negative feedback when appropriate without fear of retaliation. The solution is based on several primitive cryptographic mechanisms; e-cash, designated verifier proof and knowledge proof. In some settings it is desirable for the reputation owner to control the distribution of its own reputation and to disclose this at its discretion to the intended parties. To realize this, a solution based on a certificate mechanism is proposed. This solution allows the reputation owner to keep the certificate and to distribute its reputation while not being able to alter that information without detection. The proposed solutions cater for two modes of reputation systems: centralised and decentralised. The provision of an off-line reputation system is discussed by proposing a new solution using certificates. This is achieved through the delegation concept and a variant of digital signature schemes known as proxy signatures. The thesis presents a security architecture of reputation systems which consists of different elements to safeguard reputation systems from malicious activities. Elements incorporated into this architecture include privacy, verifiability and availability. The architecture also introduces Bayesian approach to counter security threat posed by reputation systems. This means the proposed security architecture in the thesis is a combination of two prominent approaches, namely, Bayesian and cryptographic, to provide security for reputation systems. The proposed security architecture can be used as a basic framework for further development in identifying and incorporating required elements so that a total security solution for reputation systems can be achieved.

The three most common rock mass classification systems in use in the South African mining industry today are Bieniawski’s (1976) Geomechanics or RMR System, Barton et al.’s (1974) Q-System and Laubscher’s (1990) MRMR System respectively. Of these three systems, only the MRMR Classification System was developed specifically for mining applications, namely caving operations. In response to the increased use of the MRMR Classification System in the mining industry, and concerns that the MRMR System does not adequately address the role played by discontinuities, veins and cemented joints in a jointed rock mass, Laubscher and Jakubec introduced the In-Situ Rock Mass Rating System (IRMR) in the year 2000. A quantitative comparison of the MRMR and IRMR Classification Systems has been undertaken to determine a correlation between the two classification systems, the results of which indicate that there is not a major difference between the resultant rock mass rating values derived from the two Classification Systems. Therefore, although the IRMR System is more applicable to a jointed rock mass than the MRMR System, the MRMR System should not be regarded as redundant, as it still has a role to play as a mine design tool.

五年前首次接觸『企業社會責任』的議題，驚訝之餘，更縈绕在心頭。身為報導產業經濟的記者，親眼目睹台灣企業汲汲營營戮力爭取優勢、掌握商機、贏得客戶尊重與市場支持。然而，現今企業經營環境趨向全球化，台灣企業別無選擇，勢必要走入國際，與全球接軌。當西方先進國家與亞洲鄰邦的官方與企業，自發性地實施善盡企業社會責任，成為企業公民，遵行海外投資準則及相關規範。那麼台灣政府及企業是否應該正視推動及實施企業社會責任，以獲得國際社會的認同與期望呢? 及至2005年秋天返回母校攻讀EMBA，得知歐美先進國家的公司行號已於1984年開始參與實施企業社會責任。另外，亞洲近鄰國家及地區，例如日本、新加坡、香港、馬來西亞，甚至中國大陸也從1995年開始，積極展開實施企業社會責任，尤其在市場構面的三大評等架構上。目前這些國家及地區已有自行建置的企業社會責任投資指數及社會責任投資基金。 反觀台灣實施企業社會責任的現況，在市場構面的三大評等架構(包括企業社會責任評量制度、企業社會責任投資指數及社會責任投資基金)，尚未自行建立。冀望不久的將來，臺灣能有自行建立的三大評等架構，這樣，台灣公司在研發製造技術領先鄰近開發中國家又緊追西方先進國家之際，在實施企業社會責任方面，也能迎頭趕上，甚至居於領先地位。 本論文的研究目的為下列四項: 壹、研究國內外企業社會責任的現況及其比較 貳、提出西班牙Leadtad Foundation 對非營利組織的九項評估標準也可作為評量企業社會責任的參考 參、提出企業價值平均年增率為企業社會責任的評量機制之一 肆、建議企業社會責任發展的三大構面作為落實企業社會責任的執行。 三大構面為規範遵循、市場力量及與非營利機構成為夥伴。 / Five years ago, when I first read the issue of corporate social responsibility (CSR), I was surprised and very much impressed. In the autumn of 2005, I went back to National Chengchi University for my EMBA degree, and since then, I have learnt that corporates in Europe and America have begun their CSR practice in 1984. In addition, our neighbouring Asian countries including Japan, Singapore, Hong Kong, Malaysia and even Mainland China began CSR practice starting from 1995. These Asian countries now have their own-designed CSR Investment Index and Social Investmnent Fund. However, in Taiwan, we still do not have our own-designed CSR Investment Index or Social Investment Fund. For the CSR Rating, only two magazines—Common Wealth and Gloval Views are doing questionaire investigation. I sincerely hope that Taiwan will very soon have its own developed CSR rating system, CSR Investment Index and Social Responsibility Fund. As the matter of fact, Taiwan’s research and design as well as manufacturing technologies are on ahead of its neighbouring developing countries and chase after the developed countries in the West. For CSR practice, I expect Taiwan will also chase after the Western countries’ performance and even become the leader among the countries. The four research purposes of this essay are as follows: 1. A research on updated CSR practice in Taiwan and around the world. 2. The Nine Standards of Transparency and Sound Practice from Leadtad Foundation in Spain may be used as the reference for CSR rating system. 3. Submit annual-- average –corporate-- value increase rate will be one of CSR rating method. 4. Suggest three CSR development frameworks for CSR practice. The three frameworks are as follows: 1. Follow the local and global laws and regulations regarding CSR. 2. Market influence to CSR. 3. To be partner with non-profit organizations for CSR practice. Finally, I would like to thank Professor Eric C. M. Wu, Professor M. S. Jiang, Professor Peter Huang, Professor Jason Wang, and Professor C. Y. Hsu for their guidance. Once again, my sincere appreciations to Delta Electronics, Department of Investment Services of the Ministry of Economic Affairs, Gretai Securities Market, Taiwan Mobile, Chunghwa Telecom, Lite-0n Group, Himalaya Foundation, Business Council For Sustainable Development, Taiwan, Global Views Magazine and Common Wealth Magazine for their either acceptance of interviews or providing information materials.

Mobile apps (or apps) are software applications developed to run on mobile devices such as smartphones and tablets, among other devices. The number of apps has grown tremendously since Apple opened the first app store in 2008. For example, in March of 2009 the Google Play app store (formerly known as Android Market) had only 2,300 apps, and by mid of 2013 there were more than 800,000 apps. Given the accelerated rate of growth in the number of apps, new software engineering challenges have emerged in order to help ease the software development practices of app developers. In this thesis we examine three examples of these challenges, namely code reuse in mobile apps, app ratings, and the use of ad libraries within apps. We carry out our case studies on thousands of Android apps from the Google Play market. We find that code reuse in mobile apps is considerably higher than in desktop/server apps. However, identical copies of mobile apps are rare. We find that the current ratings system is not able to capture the dynamics of the evolving nature of apps. Thus, we were able to show the need for a more elaborate rating system for the apps. Finally, we observe that a considerable number of free-to-download apps are dependant on ads for their revenue. Our findings suggest that "ad maintenance" is a tough challenge that developers of mobile apps have to face. / Thesis (Master, Computing) -- Queen's University, 2013-08-04 22:03:54.577