Human motion quality and accuracy measuring method for human–robot physical interactions

Intelligent Service Robotics - In human–robot collaboration (HRC), human motion capture can be considered an enabler for switching autonomy between humans and robots to create efficient and...     

“Restorying” Science Education Based on Local Spiritual and Cultural Values: The Case of Ethiopia

Abstract

Research demonstrates how enjoyable and meaningful learning is for children when there is smooth transition between home and classroom. This autoethnographic research used in-depth interviews and observations to examine the Ethiopian people's spiritual centered lifestyle at home and whether this style is carried into science classes in the schools. Findings indicated that the current science education in Ethiopia is ignorant of reality at home. The research proposes a new way of looking at science. It interrogates the idea that science has primacy over spirituality and, rather, recommends Ethiopian spirituality to be the standard of science and its education.     

A SCADA testbed for investigating cyber security vulnerabilities in critical infrastructures

Supervisory Control and Data Acquisition (SCADA) systems are widely used in critical infrastructures such as water distribution networks, electricity generation and distribution plants, oil refineries, nuclear plants, and public transportation systems. However, the increased use of standard protocols and interconnectivity has exposed SCADA systems for potential cyber-attacks. In recent years, the cyber-security of SCADA systems has become a hot issue for governments, industrial sectors and academic community. Recently some security solutions have been proposed to secure SCADA systems. However, due to the critical nature of SCADA systems, evaluation of such proposed solutions on real system is im-practical. In this paper, we proposed an easily scalable and reconfigurable virtual SCADA security testbed, which can be used for developing and evaluating SCADA specific security solutions. With Distributed Denial of Service (DDoS) and false data injection attack scenarios, we demonstrated how attackers could disrupt the normal operation of SCADA systems. Experimental results show that, the pro-posed testbed can be effectively used for cyber security assessment and vulner-ability investigation on SCADA systems. One of the outcomes of this work is a labeled dataset, which can be used by researchers in the area of SCADA security.     

Characteristics of drought indices and rainfall in Lake Chad Basin

A basin-scale analysis of the spatial and temporal distribution of drought indices and rainfall characteristics was performed in Lake Chad Basin (LCB), located at the Sahelo–Sudanian transition zone of West Africa. The research aims to improve our understanding of distribution, scenarios, and location-specific probability distribution of rainfall in the basin. Dekadal variability and trends were constructed and analysed using a geographic information system geoprocessing tool. There is a good correlation between the Tropical Rainfall Measuring Mission (TRMM 3B43) monthly rainfall and Global Precipitation Climatology Centre (GPCC) gauge with a correlation coefficient of 0.98. Climate Prediction Centre (CPC) Rainfall Estimate (RFE), Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) (eMODIS) normalized difference vegetation index images, global net primary production (NPP) anomaly, and standard precipitation index (SPI) were characterized. Results indicate an increase in NPP and SPI values from 2002 to 2011, which supports the theory of recent greening of the Sahel. Autocorrelation analysis identified a very high drought index at the northernmost part of LCB (proximal to the Sahara Desert) with the northern part of LCB characterized as low–low, suggesting more likelihood of low rainfall, and southeast and southwest portions as high–low, suggesting a decrease in likelihood of high precipitation northward. This provides vital information to farmers and relevant authorities for making educated decisions in poor rainy seasons. The statistical coefficient of variance and rainfall average also provide crucial information on region-specific rainfall needs for crop production.     

Heterogeneous catalysis for biodiesel production from Jatropha curcas oil (JCO)

This work focuses on the development of heterogeneous catalysts for biodiesel production from high free fatty acid (FFA) containing Jatropha curcas oil (JCO). Solid base and acid catalysts were prepared and tested for transesterification in a batch reactor under mild reaction conditions. Mixtures of solid base and acid catalysts were also tested for single-step simultaneous esterification and transesterification. More soap formation was found to be the main problem for calcium oxide (CaO) and lithium doped calcium oxide (Li-CaO) catalysts during the reaction of jatropha oil and methanol than for the rapeseed oil (RSO). CaO with Li doping showed increased conversion to biodiesel than bare CaO as a catalyst. La₂O₃/ZnO, La₂O₃/Al₂O₃ and La_0.1Ca_0.9MnO₃ catalysts were also tested and among them La₂O₃-ZnO showed higher activity. Mixture of solid base catalysts (CaO and Li-CaO) and solid acid catalyst (Fe₂(SO₄)₃) were found to give complete conversion to biodiesel in a single-step simultaneous esterification and transesterification process.     

With or without microcomputers : A dilemma

The emergence of microcomputers in the early 80s created a confused atmosphere in the information technology (IT) users' world. Especially, in developing countries, the decision on what type of hardware to acquire for day-to-day data processing needs of organizations was at the mercy of somewhat inadequate hardware vendor specifications. This being the case, a study was conducted in a composite organization of associated labour (COAL - a Yugoslav terminology for complex business organization - equivalent to corporation), to determine whether microcomputers (micros) could or could not be adapted to support data processing in conjunction with the existing mainframe. The research is based on samples gathered from a COAL that consists of nine different work organizations (WO), equivalent to middle size business organizations, which in turn consist of 27 firms or basic organizations of associated labour (BOAL). The study involved 350 employees whose day-to-day work assignment is linked with the existing data processing system, and those whose work assignment could have been supported by IT. The results are analyzed and implications outlined and discussed.     

Reproducible fabrication method for polarization preservingsingle-mode fiber couplers

The adaptation of the biconically-tapered-fused (BTF) fiber coupler fabrication approach to polarization preserving fiber couplers is reported. Two practical methods for identifying and aligning the birefringent axes of the fibers forming the coupler are described. The fabrication approaches are highly reproducible and the 3-dB couplers fabricated exhibit less than 1.0-dB insertion loss, controllable splitting ratio, and an average polarization extinction ratio of 15 to 20 dB     

Monotony analysis and sparse-grid integration for nonlinear chance constrained process optimization

The numerical solution of a nonlinear chance constrained optimization problem poses a major challenge. The idea of back-mapping as introduced by M. Wendt, P. Li and G. Wozny in 2002 is a viable approach for transforming chance constraints on output variables (of unknown distribution) into chance constraints on uncertain input variables (of known distribution) based on a monotony relation. Once transformation of chance constraints has been accomplished, the resulting optimization problem can be solved by using a gradient-based algorithm. However, the computation of values and gradients of chance constraints and the objective function involves the evaluation of multi-dimensional integrals, which is computationally very expensive. This study proposes an easy-to-use method for analysing monotonic relations between constrained outputs and uncertain inputs. In addition, sparse-grid integration techniques are used to reduce the computational time decisively. Two examples from process optimization under uncertainty demonstrate the performance of the proposed approach.     

Autotransformer fed traction power supply system: analysis,modeling and simulation

For many decades, Ethiopia had been using a meter gauge railway from Addis Ababa to the red sea port of Djibouti. Currently, the century old railway is completely replaced by a brand new standard gauge electrified railway line aiming to connect the country to the global market by guaranteeing a unified access to different regions of the country. In order to meet modern railway standards, a 1 x 25 kV catenary system is adopted in Ethio-Djibouti railway line corridor. In this paper, an alternative and a more superior 2 x 25 kV traction power supply system is presented. The modeling and analysis of the 2 x 25 kV traction supply system including the traction load, the substation power transformer, the autotransformer(AT), the catenary line impedance, etc., are performed. In addition, in order to validate the benefits of the proposed system, a comparative analysis of the two types of traction power supply arrangement has been conducted using MATLAB simulation. The analysis focuses on evaluating the voltage profiles of both power supply configurations on the basis of BS EN 50163:2004 international standard.