Near-Field and Far-Field Analyses of Alternating Impedance Electromagnetic Bandgap (AI-EBG) Structure for Mixed-Signal Applications

This paper presents near-field (NF) and far-field (FF) analysis of alternating impedance electromagnetic bandgap (AI-EBG) structure in packages and boards. Three test vehicles have been designed and fabricated for NF and FF measurements. Simulation results using a full-wave solver (SONNET) have been compared with measurement results. This paper investigates the radiation due to return current on different reference planes. The analysis results from simulations and measurements provide important guidelines for design of the AI-EBG structure based power distribution network for noise isolation and suppression in mixed-signal systems     

Tertiary treatment of biologically treated piggery wastewater using vibratory shear-enhanced RO membrane.

This study presents a good example for the tertiary treatment of biologically treated piggery wastewater using vibratory shear enhanced RO membrane (VSEP RO). Through a simple process combination, utilizing Bioceramic SBR(BCS) and VSEP RO, at Gimhae plant livestock wastewater is treated excellently to meet the strict effluent standards. Application of RO membrane directly to the biologically treated effluent has been successful without any pretreatment to reduce high suspended solids. The combination of VESP UF followed by RO filtration processes produced a higher recovery rate in the 3-week pilot test.     

Robust backstepping controller for grid‐side converter of DFIG‐based wind energy conversion systems

A robust backstepping controller with nonlinear damping is designed for the grid‐side converter (GSC) of a grid‐connected doubly fed induction generator (DFIG) in wind energy conversion systems (WECSs). The designed controller achieves the exponential ultimate boundedness of both the DC‐link voltage and GSC current errors with an arbitrarily fast decay rate and an arbitrarily small bound in the presence of both model uncertainties and time‐varying external disturbances. A desirable feature that distinguishes the proposed controller from other existing controllers is that the control input of GSC is constructed only by the static feedback of the measurable states. As a result, the control input becomes smooth and easy to implement without requiring differentiation or switching operations. The exponential boundedness and performance of the designed controller are demonstrated by simulation using a 1.5‐MW DFIG‐based WECS model built in MATLAB/SimPowerSystems and compared with a standard proportional‐integral controller. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Repositioning of Thiourea-Containing Drugs as Tyrosinase Inhibitors

Tyrosinase catalyzes two distinct sequential reactions in melanin biosynthesis: The hydroxylation of tyrosine to dihydroxyphenylalanine (DOPA) and the oxidation of DOPA to dopaquinone. Developing functional modulators of tyrosinase is important for therapeutic and cosmetic purposes. Given the abundance of thiourea moiety in known tyrosinase inhibitors, we studied other thiourea-containing drugs as potential tyrosinase inhibitors. The thiourea-containing drugs in clinical use were retrieved and tested for their ability to inhibit tyrosinase. We observed that methimazole, thiouracil, methylthiouracil, propylthiouracil, ambazone, and thioacetazone inhibited mushroom tyrosinase. Except for methimazole, there was limited information regarding the activity of other drugs against tyrosinase. Both thioacetazone and ambazone significantly inhibited tyrosinase, with IC₅₀ of 14 and 15 μM, respectively. Ambazone decreased melanin content without causing cellular toxicity at 20 μM in B16F10 cells. The activity of ambazone was stronger than that of kojic acid both in enzyme and melanin content assays. Kinetics of enzyme inhibition assigned the thiourea-containg drugs as non-competitive inhibitors. The complex models by docking simulation suggested that the intermolecular hydrogen bond via the nitrogen of thiourea and the contacts via thione were equally important for interacting with tyrosinase. These data were consistent with the results of enzyme assays with the analogues of thiourea.     

GA‐Based Multi‐Objective Optimization for Retrofit Design on a Multi‐Core PC Cluster

This article presents a distributed nondominated sorting genetic algorithm II (NSGA‐II) for optimal seismic retrofit design using buckling restrained braces (BRBs) on a cluster of multi‐core PCs. In the formulation, two conflicting objective functions of the initial BRB installation cost required for seismic retrofitting and damage cost that can be incurred by earthquakes expected during the life cycle of the structure were minimized. Because time‐consuming nonlinear structural analyses are required for fitness evaluations of individuals in every generation, parallelism at candidate design level or individual level is exploited by assigning fitness evaluations for individuals to slave core processors evenly. The distributed algorithm is applied to seismic retrofit design of 2D steel frame structure and 3D irregular reinforced concrete structure. The performance of the distributed NSGA‐II was assessed based on three criteria: convergence of the distributed algorithm, efficiency of distributed computing, and quality of optimal solutions. Implementation of the distributed algorithm on the multi‐core cluster consisting of up to 64 core processors resulted in relatively high speedups or efficiencies of the distributed optimization without deteriorating the quality of the optimal solutions.     

A mobility-based load control scheme in Hierarchical Mobile IPv6 networks

By introducing a mobility anchor point (MAP), Hierarchical Mobile IPv6 (HMIPv6) reduces the signaling overhead and handoff latency associated with Mobile IPv6. In this paper, we propose a mobility-based load control (MLC) scheme, which mitigates the burden of the MAP in fully distributed and adaptive manners. The MLC scheme combines two algorithms: a threshold-based admission control algorithm and a session-to-mobility ratio (SMR)-based replacement algorithm. The threshold-based admission control algorithm gives higher priority to ongoing mobile nodes (MNs) than new MNs, by blocking new MNs when the number of MNs being serviced by the MAP is greater than a predetermined threshold. On the other hand, the SMR-based replacement algorithm achieves efficient MAP load distribution by considering MNs’ traffic and mobility patterns. We analyze the MLC scheme using the continuous time Markov chain in terms of the new MN blocking probability, ongoing MN dropping probability, and binding update cost. Also, the MAP processing latency is evaluated based on the M/G/1 queueing model. Analytical and simulation results demonstrate that the MLC scheme outperforms other schemes and thus it is a viable solution for scalable HMIPv6 networks.     

Design of an Internal Antenna with Near‐Omnidirectional H‐Plane Radiation Pattern over Ultra‐wide Bandwidth

In this paper, an ultra‐wideband internal antenna for use in mobile applications is proposed. The proposed antenna has symmetrical bi‐arm structures printed on the top and bottom of the substrate, and it occupies a compact area of 10 mm × 10 mm × 1 mm. The designed antenna has an impedance bandwidth from 3 GHz to 12 GHz and near omnidirectional radiation patterns over the frequency band of interest. The group delay between two antennas fabricated using the proposed design is less than 0.8 ns, and the maximum gain variation is about 3.16 dB.     

A tree-based slot allocation algorithm for loss-free slotted OBS networks

Optical burst switching (OBS) is regarded as one of the most promising switching technologies for next generation optical networks. However, the data burst contention problem is still unresolved thoroughly even though slotted OBS (SOBS) is studied as a new paradigm reducing the blocking rate. In this article, we propose a tree-based slot allocation (TSA) algorithm for loss-free SOBS networks, where the TSA algorithm originally avoids contention of the time-slots by reserving the time-slots with different time-slot positions for the source nodes, respectively. In order to manage the time-slots efficiently, we also propose an OBS superframe, which is a cyclic period and consists of multiple time-slots transmitted by the source nodes toward the same incoming port of a destination node. In addition, we attempt to optimize multiplexing of the OBS superframes to reduce wavelength consumption. On the other hand, when incoming traffic is beyond expectation, a source node may need more time-slots to prevent packet loss because of buffer overflow. For reallocation of the time-slots, we propose a flow control scheme managing some number of shared time-slots, where a control node adaptively allocates (or redeems) the time-slots to (or from) source nodes by utilizing the shared time-slots based on fluctuating traffic condition. Simulation results show that the blocking rate of the proposed TSA–OBS scheme is zero with acceptable queueing delay at moderate traffic offered loads. In addition, multiplexing optimization simulated in the 14-node NSFNET achieves a 63% reduction of wavelength consumption. Moreover, the proposed flow control scheme assisting the TSA algorithm maintains a target upper-bound of queueing delay at the source node, so that packet loss caused by buffer overflow is prevented.     

A Fully-Differential Complementary Hartley VCO in 0.18 m CMOS Technology

In this letter, a new complementary Hartley (C-Hartley) voltage controlled oscillator (VCO) with fully differential outputs is proposed, in which the self-biasing configuration is introduced to solve the biasing difficulty of a Hartley VCO by employing a five-port transformer. The proposed C-Hartley VCO with the center frequency of 5.6 GHz is implemented in a 1P6M 0.18 $mu$m CMOS process. The measurement result shows that the phase noise is ${-}123.6$ dBc/Hz at 1 MHz offset frequency, while dissipating 6.5 mA from 1.6 V supply with the FOM of ${-}188.5$ dBc.