Effects of excessive speeding and falling asleep while driving on crash injury severity in Ethiopia: A generalized ordered logit model analysis

The severity of injury from vehicle crash is a result of a complex interaction of factors related to drivers’ behavior, vehicle characteristics, road geometric and environmental conditions. Knowing to what extent each factor contributes to the severity of an injury is very important. The objective of the study was to assess factors that contribute to crash injury severity in Ethiopia. Data was collected from June 2012 to July 2013 on one of the main and busiest highway of Ethiopia, which extends from the capital Addis Ababa to Hawassa. During the study period a total of 819 road crashes was recorded and investigated by trained crash detectors. A generalized ordered logit/partial proportional odds model was used to examine factors that might influence the severity of crash injury. Model estimation result suggested that, alcohol use (Coef. = 0.5565; p-value = 0.017), falling asleep while driving (Coef. = 1.3102; p-value = 0.000), driving at night time in the absence of street light (Coef. = 0.3920; p-value = 0.033), rainfall (Coef. = 0.9164; p-value = 0.000) and being a minibus or vans (Coef. = 0.5065; p-value = 0.013) were found to be increased crash injury severity. On the other hand, speeding was identified to have varying coefficients for different injury levels, its highest effects on sever and fatal crashes. In this study risky driving behaviors (speeding, alcohol use and sleep/fatigue) were a powerful predictor of crash injury severity. Therefore, better driver licensing and road safety awareness campaign complimented with strict police enforcement can play a pivotal role to improve road safety. Further effort needed as well to monitor speed control strategies like; using the radar control and physical speed restraint measures (i.e., rumble strips).     

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.     

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     

Sponge-based materials for oil spill cleanups: A review

Elimination of leaked oil from aquatic environs has recently gained importance owing to the disasters associated with leakages into marine environments. The need for an environmentally friendly and viable line of action concerning the environs has brought forward numerous affordable, non-toxic, and decomposable materials; further, diverse biomasses for fabricating nano- to micro-scale materials, membranes, and sponges/aerogels have also been incorporated for the elimination and retrieval of oils from water. Moreover, selectivity, sorption capacity, and reusability of these materials after the retrieval of oils are also desired from the viewpoint of sustainability. This review encompasses the recent progress in the field of elimination and retrieval of oil spills using various sponge-based materials.     

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.     

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.