• Structural Engineering and Mechanics
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• v.47 no.2
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• pp.287-305
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• 2013

Economic performances of consecutive multi-span suspension bridges are studied. The material amount and cost estimation formulas of the bridges have been derived in the part 1 of the study. A parametric study is carried out based on the formulas for investigating the different factors' effect on the bridge cost. The factors include the bridge sag, the bridge span, the bridge foundation and the environment condition, etc. Then, an economical layout of the bridges is proposed for different conditions. Lastly, a selection of suspension bridge types is discussed based on the economy of bridges.

• Journal of Power Electronics
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• v.14 no.3
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• pp.608-620
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• 2014

In this paper, an adaptive neural phase-locked loop (AN-PLL) based on adaptive linear neuron is proposed for grid-connected doubly fed induction generator (DFIG) synchronization. The proposed AN-PLL architecture comprises three stages, namely, the frequency of polluted and distorted grid voltages is tracked online; the grid voltages are filtered, and the voltage vector amplitude is detected; the phase angle is estimated. First, the AN-PLL architecture is implemented and applied to a real three-phase power supply. Thereafter, the performances and robustness of the new AN-PLL under voltage sag and two-phase faults are compared with those of conventional PLL. Finally, an application of the suggested AN-PLL in the grid-connected DFIG-decoupled control strategy is conducted. Experimental results prove the good performances of the new AN-PLL in grid-connected DFIG synchronization.

• Parasites, Hosts and Diseases
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• v.55 no.5
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• pp.491-503
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• 2017

The effects of tyrosine kinase inhibitors (TKIs) were evaluated on growth inhibition of intracellular Toxoplasma gondii in host ARPE-19 cells. The number of tachyzoites per parasitophorous vacuolar membrane (PVM) was counted after treatment with TKIs. T. gondii protein expression was assessed by western blot. Immunofluorescence assay was performed using Programmed Cell Death 4 (PDCD4) and T. gondii GRA3 antibodies. The TKIs were divided into 3 groups; non-epidermal growth factor receptor (non-EGFR), anti-human EGFR 2 (anti-HER2), and anti-HER2/4 TKIs, respectively. Group I TKIs (nintedanib, AZD9291, and sunitinib) were unable to inhibit proliferation without destroying host cells. Group II TKIs (lapatinib, gefitinib, erlotinib, and AG1478) inhibited proliferation up to 98% equivalent to control pyrimethamine ($5{\mu}M$) at $20{\mu}M$ and higher, without affecting host cells. Group III TKIs (neratinib, dacomitinib, afatinib, and pelitinib) inhibited proliferation up to 98% equivalent to pyrimethamine at $1-5{\mu}M$, but host cells were destroyed at $10-20{\mu}M$. In Group I, TgHSP90 and SAG1 inhibitions were weak, and GRA3 expression was moderately inhibited. In Group II, TgHSP90 and SAG1 expressions seemed to be slightly enhanced, while GRA3 showed none to mild inhibition; however, AG1478 inhibited all proteins moderately. Protein expression was blocked in Group III, comparable to pyrimethamine. PDCD4 and GRA3 were well localized inside the nuclei in Group I, mildly disrupted in Group II, and were completely disrupted in Group III. This study suggests the possibility of a vital T. gondii TK having potential HER2/4 properties, thus anti-HER2/4 TKIs may inhibit intracellular parasite proliferation with minimal adverse effects on host cells.

• Journal of Electrical Engineering and Technology
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• v.1 no.2
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• pp.170-176
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• 2006

This paper proposes a topological locating algorithm to determine the location of the power quality event source. This algorithm makes use of the information on the topology of the monitored network and on the direction of PQ events. As a result, the bus incidence matrix is modified using monitor location and the direction matrix is constructed. With this information, the algorithm determines the suspected locations of the PQ events. To reduce suspicious areas, it utilizes event cause and related equipment. In case of line fault event, it calculates the distance from the monitor to the location of event source. The overall algorithm is applied to the IEEE test feeder and accurately identifies the event source location.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.286-286
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• 2009

According to previous report, aged sleeves for old transmission lines have various defect such as biased installation or corrosion of steel sleeve. These defects can cause serious accidents such as rapid increasing of sag or falling out of overhead conductor from sleeves. Moreover, the defects have been limited power capacity of transmission line. This paper study on mechanical and thermal behavior of ACSR $410mm^2$ conductor and sleeve with various defect model. The conductor has been aged artificially for 50 years. The detailed results were presented in the text.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.643-653
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• 2017

The paper presents controller optimization algorithm for a 12-pulse voltage source converter (VSC) based high voltage direct current (HVDC) system. To get an optimum algorithm, three methods namely conventional-Zeigler-Nichols, linear-golden section search (GSS) and stochastic-particle swarm optimization (PSO) are applied to control of 12 pulse VSC based HVDC system and simulation results are presented to show the best among the three. The performance results are obtained under various dynamic conditions such as load perturbation, non-linear load condition, and voltage sag, tapped load fault at points-of-common coupling (PCC) and single-line-to ground (SLG) fault at input AC mains. The conventional GSS and PSO algorithm are modified to enhance their performances under dynamic conditions. The results of this study show that modified particle swarm optimization provides the best results in terms of quick response to the dynamic conditions as compared to other optimization methods.

• Journal of Electrical Engineering and Technology
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• v.4 no.2
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• pp.168-174
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• 2009

An application of wavelet analysis to power system transient generated signals is presented in this paper. With the time-frequency localisation characteristics embedded in wavelets, the time and frequency information of a waveform can be presented as a visualised scheme. This feature is very important for non-stationary signals analysis such as the ones generated from power system disturbances. Unlike the Fourier transform, the wavelet transform approach is more efficient in monitoring fault signals as time varies. For time intervals where the function changes rapidly, this method can zoom in on the area of interest for better visualisation of signal characteristics.

• Structural Engineering and Mechanics
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• v.25 no.2
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• pp.219-237
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• 2007

The effect of cable loosening on the nonlinear parametric vibrations of inclined cables is discussed in this paper. In order to overcome the small-sag limitation in calculating loosening for inclined cables, it is necessary to first derive equations of motion for an inclined cable. Using these equations and the finite difference method, the effect of cable loosening on the nonlinear parametric response of inclined cables under periodic support excitation is evaluated. A new technique that takes into account flexural rigidity and damping is proposed as a solution to solve the problem of divergence. The regions of inclined cables that undergo compression are also indicated.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.239-253
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• 2000

영종대교는 2000년대 수도권 항공수요에 대비하여 영종도와 용유도 일원의 간석지에 건설되어, 인천국제공항과 인천 경서동을 연결하는 총연장 4,420m의 해상교량으로 현수교 3경간(550m), Truss교 18경간 (2,250m), 강상형교 27경간(1.620m)로 구성되어 있다. 영종대교는 10개 차선, 철도 2개 차선의 교량으로 건설된다. 교량이 건설되는 해역은 10,000ton급 선박의 통행이 가능하도록 교하공간 35m의 현수교를 계획 하였으며 경제성을 고려하여 Cable을 보강형에 정착시켰다. 미관을 고려한 경간 분할에 따른 교량의 부상을 방지하기 위하여 단부교각에 Link 구조를 설치하고 접속교를 Counterweight로 이용하였으며 Cable 장력이 저감되도록 Sag비를 1/5(=f/1)로 설정하였다.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.790-799
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• 2018

This paper proposes a single-phase unified power quality conditioner (S-UPQC) for maintaining power quality issues in a microgrid. The S-UPQC can compensate the voltage and current harmonics, voltage sag, and swell as a dynamic voltage restorer (DVR), regardless of variations in the grid frequency. Odd harmonics are treated as even-order harmonics in a rotating frame to implement the harmonic compensators with only one repetitive controller (RC) without any harmonic extractor. The dynamic performance is improved and the delay time is reduced in the RC. The S-UPQC control scheme is designed to maintain accurate and stable operation under deviations of the grid frequency by using the Lagrange interpolation-based finite-impulse-response (LIFIR) filter approximation method. The proposed control schemes were validated through a simulation and experiment.