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.     

Ruthenium(II)‐ or Rhodium(III)‐Catalyzed Grignard‐Type Addition of Indolines and Indoles to Activated Carbonyl Compounds

The ruthenium(II)‐ or rhodium(III)‐catalyzed pyrimidinyl‐directed Grignard‐type C−H additions of N‐heterocycles with activated aldehydes and ketones are described. A cationic ruthenium catalyst and sodium acetate additive in dichloroethane as solvent were found to be optimal catalytic system for the construction of C‐7 alkylated indolines. In sharp contrast, a cationic rhodium complex allows the generation of C‐2 alkylated indoles and pyrroles as well as C‐1 alkylated carbazoles. The site‐selective C−H functionalization of these heterocyclic scaffolds could be an important asset towards the development of novel bioactive compounds.

     

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.      

Liver-Specific Pyruvate Dehydrogenase Complex Deficiency Upregulates Lipogenesis in Adipose Tissue and Improves Peripheral Insulin Sensitivity

The pyruvate dehydrogenase complex (PDC) plays a critical role in lipid synthesis and glucose homeostasis in the fed and fasting states. The central role of the liver in the maintenance of glucose homeostasis has been established by studying changes in key enzymes (including PDC) and the carbon-flux via several pathways under different metabolic states. In the present study we have developed a murine model of liver-specific PDC deficiency using Cre-loxP technology to investigate its consequences on lipid and carbohydrate metabolism. There was no incorporation of glucose-carbon into fatty acids by liver in vitro from liver-specific Pdha1 knockout (L-PDHKO) male mice due to absence of hepatic PDC activity. Interestingly, there was a compensatory increase in lipogenic capacity in epididymal adipose tissue from L-PDHKO mice. Both fat and lean body mass were significantly reduced in L-PDHKO mice, which might be explained by an increase in total energy expenditure compared with wild-type littermate mice. Furthermore, both liver and peripheral insulin sensitivities measured during a hyperinsulinemic-euglycemic clamp were improved in L-PDHKO mice. The findings presented here demonstrate (i) the indispensable role of PDC for lipogenesis from glucose in liver and (ii) specific adaptations in lipid and glucose metabolism in the liver and adipose tissue to compensate for loss of PDC activity in liver only.     

Supported hybrid early and late transition metal catalysts for the synthesis of polyethylene with tailored molecular weight and chemical composition distributions

Supported hybrid catalysts using metallocenes and a nickel diimine catalyst were synthesized and used for ethylene slurry polymerization and ethylene/1-hexene copolymerization. Two types of metallocenes, together with a nickel diimine catalyst were supported onto SiO₂ through chemical bonding, and a borate compound was physisorbed for the activation of the catalysts. These supported hybrid catalysts had high catalyst activities and made free-flowing polymer particles. The chemical composition distribution, molecular weight averages and distributions of resultant polymers were controlled by catalyst structure and polymerization conditions such as reaction temperature and the use of α-olefin. According to GPC-IR, ¹³C NMR and CEF characterization results of some polymers, more 1-hexene was incorporated in the high molecular weight region, short chain branches were generated by the chain walking mechanism in low molecular weight region. The morphologies of the resulting particles were investigated by SEM.     

Selective chromogenic and fluorogenic signalling of Hg ions using a fluorescein-coumarin conjugate

A novel, Hg²⁺-selective chemosensor was prepared via Mannich reaction of dichlorofluorescein with piperazinyl-coumarin moiety. The dichlorofluorescein–coumarin derivative exhibited well-defined Hg²⁺-selective chromogenic behavior, indicated by a green to pink colour change in solution, as well as fluorogenic signalling. Significant changes in fluorescence of the dichlorofluorescein subunit were analyzed in reference to the rather constant coumarin emission as an internal standard yielding Hg²⁺ selectivity. The Hg²⁺ selectivity of the chemosensor was not appreciably affected by the presence of common coexisting alkali, alkaline earth, and transition metal ions. The detection limit of the dichlorofluorescein–coumarin conjugate for the determination of Hg²⁺ ions was 4.3 × 10⁻⁶ mol L⁻¹ and the conjugate dye could be used as a chemosensor for the analysis of Hg²⁺ ions in aqueous environments.     

Physical degradation of MEA in PEM fuel cell by on/off operation under nitrogen atmosphere

The durability of PEMFCs is one of the most important issues for application in automotive vehicles with a repeated start-up and shut-down system. The understanding of degradation phenomena such as causes, mechanisms and influence of working condition is essential to improving the performance and lifetime of PEMFC. We conducted on/off cyclic operation in a single cell configuration with ultra purity nitrogen gas to investigate the physical degradation of membrane electrode assembly (MEA). After on/off cycle operation for 100,000 cycles under different humid condition, the characteristics of the MEAs were examined by in situ and ex situ analyses techniques. The physical degradation of MEA by on/off cycling led to a change in the membrane-electrode interfacial structure, which is mainly attributed to the loss of cell performance.