Coordinated Universal Time (UTC) is the standard civil time scale available via time signals in use in most parts of the world today. Leap seconds are the means to keep civil time, or UTC, aligned with adjusted Universal Time (UT1), a time based on Earth rotation corrected for polar variation. They are intentional adjustments to UTC that are instituted to prevent the difference between UT1 and UTC from exceeding +/- 0.9 seconds, based upon international agreement. Over a decade ago various technical communities for whom a continuous time scale would be more suitable than UTC, as disseminated in real-time, currently provides began making a case that the definition of UTC should be changed to eliminate leap seconds as a way to specify time unambiguously. This issue was discussed at the 2012 World Radiocommunications Conference (WRC), but consensus for elimination of the leap second was not achieved and a decision was postponed until the 2015 WRC. This report examines the leap second debate by summarizing general concepts of time and basic aspects of the leap second, followed by a discussion of non-technical considerations, technical aspects, and possible solutions. / text

On-line programming of industrial robots is time consuming and requires experience in robot programming. Due to this fact, small and medium sized enterprises are reserved about the implementation of robots in production. Ongoing research in the field is focused on finding more intuitive interfaces and methods for programming to make the interaction with robots more natural and intuitive. This master thesis presents a method for manipulation of industrial robots utilizing an external device other than the traditional teach pendant. The base of the method is a PC application which handles the program logic and the communication between an external device and an ABB robot. The program logic is designed to be modular in order to allow customization of the method, both in terms of its functions and the type of external device that is used for the method. Since gestures are one of the most common forms of communication between humans, it is interesting to investigate gestures for the purpose to make manipulation of industrial robots more intuitive. Therefore, a Leap Motion controller is presented as an example of an external device which could be used as an alternative to the teach pendant. The Leap Motion controller is specialised on hand and finger position tracking with both good absolute accuracy and precision. Further, its associated Software Development Kit (SDK) has the capabilities which are required to enable implementation of a teach pendants most fundamental functionalities. Results obtained by a user test show that the developed application is both easy and fast to use but has poor robustness.

“Rural electrification” is a key element in the global energy development agenda. While being a developing country, Sri Lanka is enroot to achieve 100% of electrification at present. After the civil war ended in 2009 which lasted for more than 25 years, there has been much focus to fulfill the energy needs of the country. But the studies carried out to assess the impact of electrification are very much limited. This study focuses on meeting the gap of carrying out a scenario analysis of rural electrification and assessing the socio economic impact of electrification. The major focus has been given to see how energy system of a newly electrified village will vary over time. The research intends to identify how far the strategies used to implement a policy is realistic in the real world. Also the research extends to apply the proposed strategies to the energy model and analyze the behavior of the model. During the study a survey was carried out in a rural village in southern part of Sri Lanka and the data obtained were used to model the energy system of the village using a software called - LEAP (Long Range Energy Alternative Planning System). The energy system is simulated under different scenarios to analyze if certain strategies in the policy have been implemented in the village. Two scenarios were energy efficient lighting and energy efficient cooking stoves. A total energy balance has been carried out for the target sample with an analysis of global warming potential of the activities of the target family. The total energy consumption variation with the electrification and the percentage of energy consumed as electricity over time has been analyzed. Further the socio economic impacts of electrification have been studied. The impact of agricultural usage and economic productivity with electricity has been studied. The qualitative measures like attitude changes, modernization & technology adaptation were addressed to the extent possible.

The objective of this thesis is to examine the extent to which the iron and steel industry in China has been a major contributor to the recent economic development and growth of the Chinese economy and whether this will continue. Key elements of China’s economic development model – THE CHINESE MODEL - based on the steel industry are presented and demonstrate the impact of China taking “great leaps forward” in its steel production capacity to become the world’s leading steel producer and one of the fastest growing economies. This bold step was undertaken at times when the global steel industry was burdened with overcapacity and economic pressures. At the same time, this thesis examines the role played by the Australian iron ore industry in supporting the Chinese steel industry through its iron ore trade with China and how this role will evolve. The development of the iron and steel industry in China reflects not just the role played in the overall expansion of the Chinese economy through technical input-output relationships, but it also reflects control and historical characteristics taken from China's social and political context. Starting from the views of Sun Yat Sen, and flowing through Mao Zedong, and then into later leaders, the steel industry was always intended to be the basis for the modernisation of the Chinese economy. The Great Leap Forward of the 1950s was an ill-founded reflection of that fundamental view, but the failure in that case did not cause a shift away from that basic perspective. Instead a more comprehensive perspective was provided and this came to the fore at the start of there form process in the early 1980s.The role of the steel industry in the recent modernisation of China is traced using the policy foundations and directions that were adopted combined with empirical data on the investment and growth in the industry, as well as the role of the output of the steel industry in the expansion of other industries in China. To the extent that conditions in China may be replicated in other countries, the Chinese experience using the iron and steel industry as the key element in the industrialisation of that economy will have important lessons. At the same time, this thesis demonstrates weaknesses in a development model that has the iron and steel industry as the leading sector. One major weakness is the reliance on imported raw materials and at this point the Chinese experience with Australia as a source of raw materials becomes relevant. Australia’s role as a reliable supplier and partner for the steel industry enabled the steel industry to expand in a low risk environment with respect to the price and availability of raw materials.

In biochemical systems, stochastic e↵ects can be caused by the presence of small numbers of certain reactant molecules. In this setting, discrete state-space and stochastic simulation approaches were proved to be more relevant than continuous state-space and deterministic ones. These stochastic models constitute the theory of stochastic reaction networks (SRNs). Furthermore, in some cases, the dynamics of fast and slow time scales can be well separated and this is characterized by what is called sti↵ness. For such problems, the existing discrete space-state stochastic path simulation methods, such as the stochastic simulation algorithm (SSA) and the explicit tau-leap method, can be very slow. Therefore, implicit tau-leap approxima- tions were developed to improve the numerical stability and provide more e cient simulation algorithms for these systems. One of the interesting tasks for SRNs is to approximate the expected values of some observables of the process at a certain fixed time T. This is can be achieved using Monte Carlo (MC) techniques. However, in a recent work, Anderson and Higham in 2013, proposed a more computationally e cient method which combines multi-level Monte Carlo (MLMC) technique with explicit tau-leap schemes. In this MSc thesis, we propose new fast stochastic algorithm, particularly designed 5 to address sti↵ systems, for approximating the expected values of some observables of SRNs. In fact, we take advantage of the idea of MLMC techniques and drift-implicit tau-leap approximation to construct a drift-implicit MLMC tau-leap estimator. In addition to accurately estimating the expected values of a given observable of SRNs at a final time T , our proposed estimator ensures the numerical stability with a lower cost than the MLMC explicit tau-leap algorithm, for systems including simultane- ously fast and slow species. The key contribution of our work is the coupling of two drift-implicit tau-leap paths, which is the basic brick for constructing our proposed drift-implicit MLMC tau-leap estimator. As an example of sti↵ problem, we used the decaying-dimerizing reaction as a test example to show the advantage of our drift-implicit method over the explicit one. Through our numerical experiments, we checked the convergence properties of our coupling algorithm and showed that our proposed estimator is outperforming the explicit MLMC estimator about three times in terms of computational work. We also illustrated in a second example how our drift-implicit MLMC tau-leap estimator can be forty times faster than the explicit MLMC.

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Technology evolves quickly, with innovative ideas growing everywhere. Still, no technology is anywhere near challenging the mouse and keyboard for navigation of your standard computer. This study focuses on comparing the traditional technologies of mouse and keyboard with the new technology of gestures - in this case Leap Motion - in purpose of finding how the usage differs and what the potential users want from the competing technology. The experiment was executed in a controlled environment, with as few external factors as possible. We found that although the test subjects found Leap Motion fun, the test subjects do not want to surf the web with gestures. Comparing the efficiency of use, mouse and keyboard took much less time, although this was expected due to experience with the traditional technology. The test subjects proposed Leap Motion to be used for playing games, 3D-modelling and for people with disabilities. Our conclusion, however, was that this technology could be successfully used in everything from hospitals to the industry, or in public places where it is important not to spread infections. We also discuss the pros and cons of Leap Motion in comparison with other gestural technologies.

Alberta is the third largest economy in Canada and is expected to grow significantly in the coming decade. The energy sector plays a major role in Albertas economy. The objective of this research is to develop various greenhouse gas (GHG) mitigations scenarios in the energy demand and supply sectors for the Province of Alberta. This is done through an energy-environment planning and forecasting tool called Long Range Energy Alternative Planning system model (LEAP). By using LEAP, a sankey diagram for energy and emission flows for the Province of Alberta has been developed. A reference case also called as business-as-usual scenario was developed for a study period of 25 years (2005-2030). The GHG mitigation scenarios encompassed various demand and supply side scenarios. In the energy conversion sector, mitigation scenarios for renewable power generation and inclusion of supercritical, ultra-supercritical and integrated gasification combined cycle (IGCC) plants were investigated. In the oil and gas sector, GHG mitigation scenarios with carbon capture and sequestration (CCS) option were considered. In Albertas residential and commercial sector 4-6 MT of CO2 equivalents per year of GHG mitigation could be achieved with efficiency improvement. In the industrial sector up to 40 MT of CO2 equivalents per year of GHG reduction could be achieved with efficiency improvement. In the energy conversion sector large GHG mitigation potential lies in the oil and gas sector and also in power plants with carbon capture and storage (CCS) option. The total GHG mitigation possible in the supply side option is between 20 70 MT CO2 equivalents per year. / Engineering Management

Boston University. University Professors Program Senior theses. / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-02

This thesis consists of three papers on child labour and schooling in Ghana. The first paper examines the correlates of child labour and schooling, as well as the trade-off between work and schooling of children aged 5-17 years with the 2013 Ghana Living Standard Survey data. A bivariate probit model is used since the decisions to participate in schooling and in the labour market are interdependent. The results show that there is a gender gap both in child work and schooling. In particular, boys are less likely to work (and more likely to be enrolled in schools) relative to girls. Whereas parent education, household wealth and income of the family are negatively correlated with child work, these factors influence schooling positively. In addition, parents‟ employment status, ownership of livestock, distance to school, child wage and schooling expenditure increase the probability of child labour and reduce the likelihood of school enrolment. In terms of the relationship between child labour and schooling, the results show that an additional hour of child labour is associated with 0.15 hour (9 minutes) reduction in daily hours of school attendance; and the effect is bigger for girls relative to boys. Also, one more hour of child labour is associated with an increase in the probability of a child falling behind in grade progression by 1.4 percentage points. The second paper estimates the impact of Ghana’s Livelihood Empowerment Against Poverty (LEAP) cash transfer programme on schooling outcomes (enrolment, attendance hours, repetition and test scores) and child labour in farming and non-farm enterprises. Using longitudinal data, the paper employs three different quasi-experimental methods (propensity score matching, difference-in-difference, and difference-in-difference combined with matching). Overall, the results show that the LEAP programme had no effect on school enrolment and test scores, but it increased the weekly hours of class attendance by 5.2 hours and reduced repetition rate by 11 percentage points for children in households that benefited from the programme. In addition, there was heterogeneity in these impacts, with boys benefiting more relative to girls. In terms of child labour, the results show that the programme had no effect on the extensive margin of child labour in farming and non-farm enterprises. However, the LEAP programme reduced the intensity of farm work done by children by as much as 2.6 hours per day. The largest impact of the programme, in terms of iii reduction in the intensity of child labour in farming, occurred in female-headed and extremely poor households. The last paper investigates the impact of mothers‟ autonomy or bargaining power in the household on their children’s schooling and child labour in Ghana. The paper uses a noneconomic measure of women’[s autonomy, which is an index constructed from five questions on power relations between men and women. The paper employs both an Ordinary Least Square (OLS) and an Instrumental Variable (IV) approach. Overall, the results suggest that ignoring the endogeneity of mothers‟ autonomy underestimates its true impact on schooling and child labour. They also show that an increase in mothers‟ autonomy increases school enrolment and hours of class attendance, with girls benefiting more than boys. The paper finds a negative relationship between mothers‟ autonomy and both the extensive and intensive margin of child labour. In addition, it demonstrates that improvement in women’s autonomy has bigger impacts on rural children’s welfare relative to urban children.