Managing Diverse Groups for Creativity

A case study suited for practising creative problem-solving is presented. Results obtained in dealing with the case are examined using a conflict-resolution framework, demonstrating the relative absence of collaborative ideas. The case can be used to sensitise groups to possible biases in idea search, and to suggest ways of compensating the bias.     

Adaptive Reinforcement Learning Strategy with Sliding Mode Control for Unknown and Disturbed Wheeled Inverted Pendulum

This paper develops a novel adaptive integral sliding-mode control (SMC) technique to improve the tracking performance of a wheeled inverted pendulum (WIP) system, which belongs to a class of continuous time systems with input disturbance and/or unknown parameters. The proposed algorithm is established based on an integrating between the advantage of online adaptive reinforcement learning control and the high robustness of integral sliding-mode control (SMC) law. The main objective is to find a general structure of integral sliding mode control law that can guarantee the system state reaching a sliding surface in finite time. An adaptive/approximate optimal control based on the approximate/adaptive dynamic programming (ADP) is responsible for the asymptotic stability of the closed loop system. Furthermore, the convergence possibility of proposed output feedback optimal control was determined without the convergence of additional state observer. Finally, the theoretical analysis and simulation results validate the performance of the proposed control structure.

     

A linear relaxation-based heuristic approach for logistics network design

We address the problem of designing and planning a multi-period, multi-echelon, multi-commodity logistics network with deterministic demands. This consists of making strategic and tactical decisions: opening, closing or expanding facilities, selecting suppliers and defining the product flows. We use a heuristic approach based on the linear relaxation of the original mixed integer linear problem (MILP). The main idea is to solve a sequence of linear relaxations of the original MILP, and to fix as many binary variables as possible at every iteration. This simple process is coupled with several rounding procedures for some key decision variables. The number of binary decision variables in the resulting MILP is small enough for it to be solved with a solver. The main benefit of this approach is that it provides feasible solutions of good quality within an affordable computation time.     

Model selection with considering the CO2 emission alone the global supply chain

This study formulates a model for analyzing eco-environmental impact on global supply chain network. The multi-criteria optimization model is applied to seek optimal solutions that not only can achieve predetermined objectives, but also can satisfy constraints for multi-product problems. The overall optimization is achieved using mathematical programming for modeling the supply chain functions such as location, inventory, production, distribution functions and transportation mode selections. Then, the supply chain model is formulated as a minimization problem for costs and environmental impacts. Herein, the solution is the flow of goods in global supply chain environment in different periods of time over one year. Furthermore, the numerical values obtained from a real company are applied to these mathematical formulations to test its usability. The testing is conducted in four different cases that include two combinations, no due date constraint and due date constraint, without connection of distributor and with connection of distributors. The results from these experiments can help in determining the best transportation routes, inventory levels, shipment quantity, and transportation modes. Specifically, the results propose a new configuration for designing global supply chain for the case company that could minimize economical and environmental impacts problems simultaneously.     

Analysis of secrecy outage performance for full duplex NOMA relay systems with appearance of multiple eavesdroppers

Full-duplex (FD) relay systems including a transmit antenna selection and a non-orthogonal multiple access (NOMA) methods are analyzed under presence of multiple eavesdroppers. A channel state information of both the considered system and eavesdroppers is assumed to be outdated and eavesdroppers eavesdrop information signals independently. A closed-form of secure outage probability (SOP), secrecy throughput of every user is derived to evaluate the secrecy performance, and the mathematical analysis approach is verified by the Monte-Carlo simulation. Furthermore, the Golden-Section Search algorithm is proposed to find the maximum of the secrecy throughput of the considered FD-NOMA system. Numerical results indicate that there exists the SOP floor in the considered system and it is constrained by the channel gain of near user. Moreover, there is the optimal signal to interference plus noise ratio value which minimizes the SOP of the system regardless of the number of eavesdroppers. In comparison with half-duplex NOMA model, the SOP of FD-NOMA model is better.

     

Evaluation of MODIS land surface temperature products for daily air surface temperature estimation in northwest Vietnam

Recently, the MODerate resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) is considered one of the most suitable ways to retrieve air surface temperature (T_a) – one of the most important and widely used climate variables for a wide range of applications. In fact, many successful studies have been reported in many regions of the world. Each day, four MODIS LST data are available; from two sensors (Terra and Aqua) at two local overpass times (daytime and night-time). However, due to their different overpass times, most studies have used LST daytime and night-time for daily maximum (T_max) and minimum (T_min) air surface temperature estimation, respectively. Therefore, the performance of each individual LST data, the effect of the dynamic combination of these four LST data, the effect of land surface characteristics, and the effect of LST quality on the same estimation in the same region on the accuracy of estimated T_a remains unclear. In this study, we evaluated and tested all individual LST data as well as all possible combinations of the four MODIS LST data from two separate stations with distinct land surface characteristics in northwest Vietnam for 10 years (from 2004 to 2013) under two sky conditions (all clear sky conditions and only good data – i.e. Quality Control (QC) value of 0) for daily T_a (T_max, T_min, and T_mean) estimations. In addition, the mixed data of the two stations were also evaluated. Our results showed that Terra LST data have a higher correlation with T_a than Aqua LST; which is consistent for both stations and both quality conditions (all clear sky and only good data). A closer overpass time with T_max or T_min occurrence time did not guarantee a higher accuracy of T_a estimation. Using only good LST data produced a higher accuracy of T_a estimation than using all clear sky data. However, if the percentage of good data is low (i.e. less than 30%), then the all clear sky data will provide better results for T_max estimation. Comparing the performance of the different combinations when using the single station and mixed station data, combinations including at least one night-time LST produced stable and high accuracy T_min and T_mean estimates, while the combinations with only daytime LST produced very low accuracy results. For T_max estimation, the results were less impacted by LST quality; however, they were strongly impacted by different combinations and land surface characteristics.     

Synthesis of oleic acid-stabilized silver nanoparticles and analysis of their antibacterial activity

The development of new and simple green chemical methods for synthesizing colloidal solutions of functional nanoparticles is desirable for environment-friendly applications. In the present work, we report a feasible method for synthesizing colloidal solutions of silver nanoparticles (Ag NPs) based on the modified Tollens technique. The Ag NPs were stabilized by using oleic acid as a surfactant and were produced for the first time by the reduction of silver ammonium complex [Ag(NH₃)₂]⁺_(aq) by glucose with UV irradiation treatment. A stable and nearly monodisperse aqueous Ag NPs solution with average-sized particles (~ 9–10 nm) was obtained. The Ag NPs exhibited high antibacterial activity against both Gram-negative Escherichia Coli (E. coli) and Gram-positive Staphylococcus aureus bacteria. Electron microscopic images and analyses provided further insights into the interaction and bactericidal mechanism of the Ag NPs. The proposed method of synthesis is an effective way to produce highly bactericidal colloidal solutions for medical, microbiological, and industrial applications.     

Influence of Dislocation Loops on the Near-Infrared Light Emission From Silicon Diodes

The infrared light emission of forward-biased silicon diodes is studied. Through ion implantation and anneal, dislocation loops were created near the diode junction. These loops suppress the light emission at the band-to-band peak around 1.1 mum. The so-called D1 line at 1.5 mum is strongly enhanced by these dislocation loops. We report a full study of photoluminescence and electroluminescence of these diodes. The results lead to new insights for the manufacturing approach of practical infrared light sources in integrated circuits.     

Simultaneous production of gaseous fuels with degradation of Rhodamine B using a 40 kHz double-bath-type sonoreactor

This work proposed a novel double-bath-type sonoreactor to demonstrate the possibility of applying ultrasound power for simultaneous production of gaseous fuels with degradation of Rhodamine B (RhB). The developed double-bath-type sonoreactor allows concentrating the energy of the ultrasonic waves to a limited region and, consequently allows the acoustic intensity in there to be increased approximately 30-fold compared to that can be created in a normal ultrasonic bath at the same applied power. The effect of acoustic intensity, temperature of water bath, static and bubbling argon atmosphere, initial RhB concentration, and dissolved gases on the sonochemical activity both in terms of RhB degradation and gaseous fuel productions were fully investigated. The possible pathways for the simultaneous production of gaseous fuels with degradation of RhB were elucidated. Sonochemical degradation of RhB was successfully analysed by Langmuir-Hinshelwood-type kinetics.     

Porous NiO via pulsed electrodeposition towards enhanced electrochromic properties

Journal of Applied Electrochemistry - Herein, a facile pulse electrodeposition procedure with a 1 s off-time between pulses is reported for a successful fabrication of porous nickel oxide...