Chen W.-H.,National Taipei University of Technology
IEEE Transactions on Power Systems | Year: 2010
Distribution system restoration is a process of finding backup feeders to restore the load in out-of-service zones by switching operations. A feasible restoration plan must satisfy some practical objectives under operational constraints. Since there may be a tradeoff between objectives, and decision preferences vary from one situation to another, how to evaluate and choose a suitable restoration plan under system emergency has become a real challenge in modern power system operation. Conventional approaches can find feasible restoration plans but fail to identify their relative performance as it is unable to make a quantitative comparison among them. In this paper, we propose a quantitative evaluation framework for ranking restoration plans with their performance indexes, using the analytical hierarchy process-based fuzzy-grey approach. Experimental results showed that the proposed method was effective and helpful in assisting operators during the restoration process. © 2009 IEEE.
Ying K.-C.,National Taipei University of Technology
European Journal of Industrial Engineering | Year: 2012
The scheduling problem of multistage hybrid flowshop with multiprocessor tasks is a core topic for numerous industrial applications but under-represented in the research literature. In this study, a new hybrid immune algorithm based on the features of artificial immune systems and iterated greedy algorithms is presented to minimise the makespan of this problem. To validate the performance of the proposed algorithm, computational experiments are conducted on two well-known benchmark problem sets. The experiment results clearly reveal that the proposed algorithm is highly effective and efficient as compared to three state-of-the-art metaheuristics on the same benchmark instances. Copyright © 2012 Inderscience Enterprises Ltd.
Che Z.H.,National Taipei University of Technology
Computers and Industrial Engineering | Year: 2010
To simplify complicated traditional cost estimation flow, this study emphasizes the cost estimation approach for plastic injection products and molds. It is expected designers and R&D specialists can consider the competitiveness of product cost in the early stage of product design to reduce product development time and cost resulting from repetitive modification. Therefore, the proposed cost estimation approach combines factor analysis (FA), particle swarm optimization (PSO) and artificial neural network with two back-propagation networks, called FAPSO-TBP. In addition, another artificial neural network estimation approach with a single back-propagation network, called FAPSO-SBP, is also established. To verify the proposed FAPSO-TBP approach, comparisons with the FAPSO-SBP and general back-propagation artificial neural network (GBP) are made. The computational results show the proposed FAPSO-TBP approach is very competitive for the product and mold cost estimation problems of plastic injection molding. © 2010 Elsevier Ltd. All rights reserved.
Wang T.-P.,National Taipei University of Technology
IEEE Microwave and Wireless Components Letters | Year: 2011
A circuit topology suitable for low-power Colpitts voltage-controlled oscillators (VCOs) is presented in this letter. By employing the proposed voltage-to-current positive-feedback network, the required transconductance for VCO startup can be reduced, leading to the minimized dc power for sustaining VCO oscillation. Moreover, the Q-factor enhanced varactor is used in this VCO design for phase noise improvement. Based on the proposed architecture, the fabricated VCO in standard 0.18 μ m CMOS exhibits a 3.58% tuning range. Operating at 1.35-V supply voltage, the VCO core consumes 3.3-mW dc power. The measured phase noise is -110.82 dBc/Hz at 1 MHz offset from 18.95 GHz oscillation frequency. Compared with the recently published K-band 0.18 μ m CMOS VCOs, it is observed that the proposed Colpitts VCO exhibits comparable circuit performance under low dc-power consumption. © 2011 IEEE.
Chang S.-Y.,National Taipei University of Technology
International Journal for Numerical Methods in Engineering | Year: 2014
A new family of unconditionally stable integration methods for structural dynamics has been developed, which possesses the favorable numerical dissipation properties that can be continuously controlled. In particular, it can have zero damping. This numerical damping is helpful to suppress or even eliminate the spurious participation of high frequency modes, whereas the low frequency modes are almost unaffected. The most important improvement of this family method is that it involves no nonlinear iterations for each time step, and thus it is very computationally efficient when compared with a general second-order accurate integration method, such as the constant average acceleration method. © 2014 John Wiley & Sons, Ltd.