• Nuclear Engineering and Technology
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• v.52 no.5
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• pp.1051-1065
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• 2020

Safety analysis of nuclear power plant (NPP) especially in accident conditions is a basic and necessary issue for applications and commercialization of reactors. Many previous researches and development works have been conducted. However, most achievements focused on the safety reliability of primary pressure system vessels. Few literatures studied the structural safety of huge concrete structures surrounding primary pressure system, especially for the fourth generation NPP which allows existing of through cracks. In this paper, structural safety reliability of concrete structures of HTR-PM in accidental double-ended break of hot gas ducts was studied by Exceedance Probability Method. It was calculated by Monte Carlo approaches applying numerical simulations by Abaqus. Damage parameters were proposed and used to define the property of concrete, which can perfectly describe the crack state of concrete structures. Calculation results indicated that functional failure determined by deterministic safety analysis was decided by the crack resistance capability of containment buildings, whereas the bearing capacity of concrete structures possess a high safety margin. The failure probability of concrete structures during an accident of double-ended break of hot gas ducts will be 31.18%. Adding the consideration the contingency occurrence probability of the accident, probability of functional failure is sufficiently low.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.54-61
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• 2016

A 6-Gbps single-ended receiver with a linear equalizer and a self-reference generator is proposed for a high-speed interface with the double data rate. The proposed single-ended receiver uses a common gate amplifier to increase a voltage gain for an input signal with low voltage level. The continuous-time linear equalizer which reduces gain to the low frequencies and achieves high-frequency peaking gain is implemented in the common gate amplifier. Furthermore, a self-reference generator, which is controlled with the resolution 2.1 mV using digital averaging method, is implemented to maximize the voltage margin by removing the offset noise of the common gate amplifier. The proposed single-ended receiver is designed using a 65-nm CMOS process with 1.2-V supply and consumes the power of 15 mW at the data rate of 6 Gbps. The peaking gain in the frequency of 3 GHz of the designed equalizer is more than 5 dB compared to that in the low frequency.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.13-14
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• 2013

Multiple output converters (MOCs) are widely used for applications which require various kinds of the output voltages due to its advantages in cost, volume, and efficiency. However, most of the MOCs developed so far can regulate only one output tightly and require as many secondary windings in the transformer as the number of the outputs. In this paper, a novel Time Division Multiple Control (TDMC) method to regulate all the outputs in high precision is proposed and applied to the double ended forward converter for the multiple battery charger. Additional benefit of the proposed topology is to require only one secondary winding in the transformer for all the outputs. The proposed converter can charge two different kinds of batteries or same kind of batteries in different state of charges (SOCs) by CC/CV mode independently with the even degree of tight regulation, thereby satisfying the ripple requirements for each battery.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1522-1530
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• 2008

This paper presents a discrete wavelet analysis based algorithm to address the fault impedance calculation under transient state in radial power distribution networks. The fault impedances have been derived under different fault conditions. Furthermore, a recursive fault distance estimation method is proposed utilizing the measured fault impedance and power line parameters. The proposed scheme can resolve the errors caused by the non-homogeneous power lines, the presence of lateral loads since, the fault impedance will always be updated with the recursive form. For the verification of the proposed scheme, a filed test has been peformed with varying fault resistances in the 22.9(kV) radial system. Power meters and fault locators were installed at the substation. It was figured out that the performance of the discrete wavelet and the recursive scheme are very good even for high fault resistance condition.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.729-736
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• 2015

In this paper, It was performed to optimize for the deck's structural design of a double ended car ferry ship respect to Goal-Driven Optimization (GDO). It was examined for the strength and deformation of the deck and determined to save economic cost the optimal point. The deck thickness based on the Design of Experiments (DOE) and response surface method was increased to 110%. and can improve the deck's strength and stiffness. By performing the regression analysis respect to the result, we propose the optimal regression model formula as a third degree polynomial regression models. The coefficient of determination $R^2$ was about 0.98 and reliability could be obtained.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2000.11a
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• pp.225-230
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• 2000

This paper describes a double-ended current fed push-pull type high frequency resonant inverter used as the power supply for wax-sealing. The proposed inverter can realize ZVS operation by using resonant capacitor to ZVS capacitor and has some merits not only reduction of switch current distribution but also extension of load range compare to the conventional single-ended current fed push-pull type high frequency resonant inverter. This analysis of proposed circuit uses normalized parameter ad characteristic estimation which is needed in each step before design is generally described according to normalized frequency($\mu$), normalized resistance(λ) and parameters. It is also presented as an example of method of the circuit design based on estimation analysis values from theoretical analysis. The theoretical analysis is proved through experiment and this circuit shows that it can be used practically as the power supply system for wax-sealing and DC-DC converter.

• Korean Journal of Organic Agriculture
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• v.28 no.3
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• pp.273-288
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• 2020

The purpose of this study is to estimate farmers' willingness to accept (WTA) of direct payment for increasing public benefit using the contingent valuation method. The double-bounded dichotomous choice and the open-ended question were used to measure WTAs for basic form and optional form, respectively. The results show that WTA for basic form was inversely proportional to the acreage. WTAs were KRW 1,694,001 with 2 ha or less, KRW 1,617,789 with over 2 ha~6 ha, and KRW 1,562,977 with over 6 ha. The results also indicate that WTAs for optional form are similar to payments of agricultural environmental conservation program except physical (chemical) control of pests and weed. The results of this study can provide useful information for the establishment of direct payment for increasing public benefit.

• The Journal of the Korea Contents Association
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• v.17 no.3
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• pp.532-541
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• 2017

Design is an extremely critical and important for the prosperity and development of a corporation, and design for children's facilities can be said to be a critical factor not only from a commercial perspective but also one of the critical factors that can be beneficial to the physical, intellectual and emotional growth and development of children. To measure the economic value of publicly designed children's facilities established with the purpose of children's design education, this research study utilized the Contingent Valuation Method. This research study attempts to provide useful information for policy administrators on the usage of both publicly designed children's facilities with high use value and also high non-use value through economic value measurement. To achieve the objectives of this research, the Contingent Valuation Method that utilized both open-ended questions and also double-bounded dichotomous choice methodologies was used. The results of the pre-verification that used the open-ended questions results from 50 test subject participants and the double-bounded dichotomous choice methodology results from 530 test subject participants confirmed that the average annual per person expense was estimated to be KRW 12,463. The gross benefit amount figure estimated for all households in the nation was estimated to be about KRW 219 billion annually.

• Journal of Mechanical Science and Technology
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• v.14 no.2
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• pp.215-225
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• 2000

The structural integrity of the fuel test loop (FTL) in a Korean experimental reactor is evaluated when the FTL, submerged in a water environment, is subjected to a postulated pipe rupture. The analyses are performed under static and dynamic conditions, imposing the thrust force history at each postulated pipe rupture section. Through analysis the following results are found: l) A double ended guillotine can not be expected based on the toughness of the material, 2) the structural integrity of the chimney surrounding the FTL would not impede the structural integrity by the pipe whip. All analyses are performed by finite element methods.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.3
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• pp.265-275
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• 2010

The main purpose of this study is to estimate willingness to pay (WTP) by the general publics, assuming that they pay tax or charge for protecting marine living resources and environment through developing and supplying biodegradable fishing nets. This study employed a contingent valuation method (CVM) which is an econometric method. The survey was conducted by using both double-bounded dichotomous choice and open-ended survey. Tobit model was used for the analysis. The variables included concerns about marine environment and fishing net discarded, sex, age profile, number of family members, educational level and personal disposable income. Annual average WTP per family for the biodegradable fishing net development and supply was estimated at 5,294 won and national WTP amounted to some 84.2 billion won. This includes both of use and non-use value of biodegradable fishing nets.