Full-duplex Distributed Massive MIMO System with Optimal Beamforming and Resource Allocation for WPCN

This paper proposes a joint beamforming and resource allocation scheme to maximize the minimum capacity for wireless powered communication network (WPCN) designed for multi-user distributed massive multi-input multi-output (DM-MIMO) system with full-duplex radio remote heads (RRHs), which enable simultaneous uplink (UL) and downlink (DL) communications. The minimum capacity is maximized by a proposed algorithm based on the non-negative matrix theory. The simulation results have demonstrated that the achievable max-min capacity of the DM-MIMO is considerably higher compared to that of the CMMIMO system. It has also showed that the convergence speed of the proposed algorithm is so fast.     

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).     

Comparing Net Radiation Estimation Methods: CIMIS versus Penman–Monteith

Net radiation (Rn) estimated using the California Irrigation Management Information System (CIMIS) Penman and the Penman–Monteith (PM) methods are compared using hourly data from July 17, 2004 to October 24, 2004. Results showed that differences between the two estimates get larger towards higher values of Rn because of the inability of the two methods to accurately estimate net outgoing longwave radiation (Rnl). This was determined by comparing the two Rn estimates against values measured using the Kipp and Zonen CNR1 net radiometer. On average, the CIMIS Penman Rn was 4% lower and the PM Rn was 8% higher when compared to the measured values. An attempt to modify the PM method for estimating Rnl resulted in significant improvements. Rn values measured by four Kipp and Zonen NR-Lite radiometers are also compared with the corresponding values measured by the CNR1. The NR-Lites performed well under the given sets of surface and environmental conditions. Average values of slope, coefficient of determination (r2), and standard error of estimates from the linear regressions of the four NR-Lites against CNR1 were 0.97, 0.99, and 18.79?W/m2, respectively.     

Enhanced Thermoelectric Performance of PEDOT:PSS Films by Sequential Post‐Treatment with Formamide

This paper reports a series of sequential post‐treatments using a polar solvent formamide to enhance the thermoelectric performance of poly(3,4‐ethylenedioxythiophene) doped with poly(styrene sulfonate) anions (PEDOT:PSS). The electrical conductivity of PEDOT:PSS films significantly increases from 0.33 S cm^?1 for the pristine film to ≈2929 S cm^?1 for the treated film and meanwhile the Seebeck coefficient maintains as high as 17.4 µV K^?1, resulting in a power factor of 88.7 µW m^?1 K^?2. Formamide is a polar solvent with a high boiling point of 210 °C and high dielectric constant of 109, and PSS has a good solubility in it. Post‐treatment with formamide causes not only the phase segregation of PEDOT and PSS but also the removal of insulating PSS, therefore leading to the reorientation of PEDOT chains and enhancement in mobility without altering the doping level considerably. The cross‐plane thermal conductivity also reduces from 0.54 to 0.19 W m^?1 K^?1 after the post‐treatment, leading to a figure of merit (ZT) value of 0.04 at room temperature.     

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.     

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