Aspect of Code Cloning Towards Software Bug and Imminent Maintenance: A Perspective on Open-source and Industrial Mobile Applications

As a part of the digital era of microtechnology, mobile application (app) development is evolving with lightning speed to enrich our lives and bring new challenges and risks. In particular, software bugs and failures cost trillions of dollars every year, including fatalities such as a software bug in a self-driving car that resulted in a pedestrian fatality in March 2018 and the recent Boeing-737 Max tragedies that resulted in hundreds of deaths. Software clones (duplicated fragments of code) are also found to be one of the crucial factors for having bugs or failures in software systems. There have been many significant studies on software clones and their relationships to software bugs for desktop-based applications. Unfortunately, while mobile apps have become an integral part of today’s era, there is a marked lack of such studies for mobile apps. In order to explore this important aspect, in this thesis, first, we studied the characteristics of software bugs in the context of mobile apps, which might not be prevalent for desktop-based apps such as energy-related (battery drain while using apps) and compatibility-related (different behaviors of same app in different devices) bugs/issues. Using Support Vector Machine (SVM), we classified about 3K mobile app bug reports of different open-source development sites into four categories: crash, energy, functionality and security bug. We then manually examined a subset of those bugs and found that over 50% of the bug-fixing code-changes occurred in clone code. There have been a number of studies with desktop-based software systems that clearly show the harmful impacts of code clones and their relationships to software bugs. Given that there is a marked lack of such studies for mobile apps, in our second study, we examined 11 open-source and industrial mobile apps written in two different languages (Java and Swift) and noticed that clone code is more bug-prone than non-clone code and that industrial mobile apps have a higher code clone ratio than open-source mobile apps. Furthermore, we correlated our study outcomes with those of existing desktop based studies and surveyed 23 mobile app developers to validate our findings. Along with validating our findings from the survey, we noticed that around 95% of the developers usually copy/paste (code cloning) code fragments from the popular Crowd-sourcing platform, Stack Overflow (SO) to their projects and that over 75% of such developers experience bugs after such activities (the code cloning from SO). Existing studies with desktop-based systems also showed that while SO is one of the most popular online platforms for code reuse (and code cloning), SO code fragments are usually toxic in terms of software maintenance perspective. Thus, in the third study of this thesis, we studied the consequences of code cloning from SO in different open source and industrial mobile apps. We observed that closed-source industrial apps even reused more SO code fragments than open-source mobile apps and that SO code fragments were more change-prone (such as bug) than non-SO code fragments. We also experienced that SO code fragments were related to more bugs in industrial projects than open-source ones. Our studies show how we could efficiently and effectively manage clone related software bugs for mobile apps by utilizing the positive sides of code cloning while overcoming (or at least minimizing) the negative consequences of clone fragments

Effect of pH and Temperature on Halogenated DBPs

Water scarcity is one of the most challenging issues in the world in the 21st century. It is estimated that there are more than one billion of people without adequate access to freshwater and facing water shortages and water deficits. People are forced to drink polluted water despite the risk of consuming pathogenic microorganisms in the water that transmit waterborne diseases such as bacterial infections, protozoal infections and viral infections. The water disinfection process is one of the most important environmental technological advances in the 20th century which inactivates microbial contaminants in drinking water. Disinfection byproducts (DBPs) are a group of chemical compounds formed from the reaction between natural organic matter and chemical disinfectants. The formation of DBPs in drinking water has caused serious health concerns since the discovery of trihalomethanes in chlorinated drinking waters in the 1970s. Many studies have evaluated factors affecting the formation of DBPs within water treatment plants. Relatively less is known about the fate of DBPs in the distribution system. The objective of this study was to evaluate the impacts of pH and temperature on the degradation of total organic chlorine (TOC1), bromine (TOBr) and iodine (TOI). In this study, we produced TOC1 (Cl2), TOBr, TOI, and TOC1 (NC2Cl) from reactions between Suwannee River fulvic acid and chlorine, bromine, iodine and chloramine, respectively. The impact of different pH values (7.0, 8.3 and 9.5) and temperatures (10°C, 20°C, 30°C, and 55°C) on the degradation of these DBPs was investigated after oxidant residuals were exhausted. The results show that halogenated DBPs degrade through based-catalyzed dehalogenation processes. The degradation of TOC1, TOBr, and TOI increased with increasing pH values. Increasing temperatures also increased the degradation kinetics of these DBPs. Iodinated DBPs were less stable than brominated DBPs, which again were less stable than chlorinated DBPs. Relatively high degradation kinetics were also found for chloraminated DBPS. In general, the relative stability of different DBPs are in the order of TOC! (Cl2)\u3eTOBr\u3eTOI≈TOC1 (NH2CL)

The Efficiency of Microcredit Applied to Social Exclusion.

Microcredit has been a tool to alleviate poverty since long. This research is aimed to observe the efficiency of microcredit in the field of social exclusion. The development of questionnaires and use of existing tools was used to observe the tangible and intangible intertwining of microcredit and by doing so the effort was concentrated to observe whether microcredit has a direct effect on social exclusion or not. Bangladesh was chosen for the field study and 85 samples were taken for the analysis. It is a time period research and one year time was set to receive the sample and working on the statistical analysis. The tangible aspect was based on a World Bank questionnaire and the social capital questionnaire was developed through different well observed tools. The borrowers of Grameen Bank in Bangladesh, is the research sample whish shows a strong correlation between their tangible activity and social life. There are significant changes in tangible aspect and social participation observed from the research. Strong correlation between the two aspects was also found taking into account that the borrowers themselves have a vibrant social life in the village

Family network and household decision making power: analysis on Grameen Microcredit borrowers in Bangladesh.

Microcredit, a system of small loans, invests in the creativity of an individual, stimulating the development of their potential. This process leads to the creation of different objectives that, in turn, allow individuals to develop their capabilities. In addition to providing economic benefits, microfinance may be an effective vehicle for women\u2019s empowerment, and newly acquired business skills may be accompanied by improvements in self-esteem, the ability to resolve conflicts, household decision making power, and improve the quality of family relationships. The aim of this study was to evaluate the effectiveness of microcredit intervention, in terms of improving the economic well-being of women and their families, and increasing benefits in terms of individual welfare, family and society. It is therefore an impact assessment study that aims to detect a significant change on new women borrowers\u2019 lives from Noakhali District at the South of Bangladesh. Manova Analysis allowed distinguishing from women with positive or negative outcomes related to the loan performance. Data revealed consistent differences in terms of economical outcomes and psychological well-being amongst the groups of subject analyzed. In this chapter we will present the preliminary results regarding the family well-being detected by two indicators: the household decision-making power and the quality of family relationships. The data gathered in relation to the changes arisen in the individuals should be looked into through future, continuous and systematic, monitoring

Study of solid waste management and its impact on climate change : a case study of Dhaka City in Bangladesh

Rapid global warming has caused fundamental changes to our climate. Specially, the people living in Dhaka city are facing the worst sufferings than any other cities in Bangladesh. The waste in Dhaka comprises mainly 60% of organic waste which can produce landfill gas (methane) upon decomposition. It could be added that waste management generates carbon dioxide and methane, with emissions occurring during almost all stages from transportation through to recycling, recovery and final disposal. This paper looks at the relationship how solid waste dumped in open space or landfill site can contribute to the generation of landfill gas and contribute to climate change in the context of Dhaka city. The waste generation, characteristics and composition are studied for Dhaka city and the landfill gas is estimated using Inter Governmental panel of Climate Change (IPCC) guideline tier-1 based on different projected scenarios. Based on these scenarios, potential measures to reduce the landfill gas emission are recommended

Numerical Study on Improving the Efficiency of the Earth Pipe Cooling System

Earth pipe cooling (EPC) is one of the passive cooling systems which has proven to be a very energy efficient sustainable cooling technique for the sub-tropical areas. This cooling system uses the soil as a medium of heat transfer. Efficiency of this system largely depends on the velocity of the cooling air, shape of the cooling space, pattern of the walls in cooling space, inlet size and position of the incoming air. It is well-known that increasing the velocity of the cooling air will improve the efficiency of the cooling system. Therefore, this study focused on the optimization of the shape and pattern of the inlet which might improve the efficiency of the cooling system. ANSYS Fluent is used to perform this simulation-based study. It is found that inclusion of aerofoil shaped turbulator in the inlet cross sectional area provide better circulation of the air inside the cooling space, thus, enhance the effectiveness of the system

Numerical Study on Improving the Efficiency of the Earth Pipe Cooling System

Earth pipe cooling (EPC) is one of the passive cooling systems which has proven to be a very energy efficient sustainable cooling technique for the sub-tropical areas. This cooling system uses the soil as a medium of heat transfer. Efficiency of this system largely depends on the velocity of the cooling air, shape of the cooling space, pattern of the walls in cooling space, inlet size and position of the incoming air. It is well-known that increasing the velocity of the cooling air will improve the efficiency of the cooling system. Therefore, this study focused on the optimization of the shape and pattern of the inlet which might improve the efficiency of the cooling system. ANSYS Fluent is used to perform this simulation-based study. It is found that inclusion of aerofoil shaped turbulator in the inlet cross sectional area provide better circulation of the air inside the cooling space, thus, enhance the effectiveness of the system