• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.7
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• pp.97-105
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• 2014

This article examines the causality relationship among SMP, base-load share, LNG import price, and exchange rate in Korean power market during 2002~2012, using unit root test, cointegration test, and vector error correction model(VECM). The cointegration test shows that 4 variables without unit root have been in the long-run causality. As the results of ECM, SMP is analyzed to have been unilaterally caused from LNG import price and base-load share in the shot-run, while it has been unilaterally caused from LNG import price and exchange rate in the long-run. This article has the following policy implications: the adjustment of exchange rate to reduce he risk of LNG import price and the proper securement of base-load share for the long-run stability of SMP.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.5
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• pp.115-121
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• 2014

The intrinsic simplicity, ruggedness, and simple power electronic drive requirement of a Switched Reluctance Motor(SRM) make it possible to use in many commercial adjustable speed application. The simple magnetic circuit results in a high efficiency drive and low temperature rise, and the drive system provides a good drive characteristics. This paper is provides two phase 4/3 SRM that is similar to two phase 6/3 SRM as aspect to magnetic structure. Although 6/3 SRM does not experience any flux reversal as the flux is in the same direction whether phase A or B is excited, but two phase 4/3 SRM experiences a flux reversal in small part of stator yoke. The flux reversal in two phase 4/3 SRM could be relieved by an adjustment of stator yoke structure. The magnetic analysis and design considerations of the two phase 4/3 SRM have been obtained by the finite element method analysis (FEM).

• Journal of the Korean Society for Precision Engineering
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• v.25 no.6
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• pp.134-142
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• 2008

In this paper, we propose a precise linear motion stage supported by magnetically preloaded air bearings. The eight aerostatic bearings with rectangular carbon porous pads were located only one side of vertical direction under the platen where four bearings are in both sides of horizontal direction as wrap-around-design, and this gives simpler configuration than which constrained by air bearings for all direction. Each of the magnetic actuators has a permanent magnet generating static magnetic flux far required preload and a coil to perturb the magnetic farce resulting adjustment of air- bearing clearance. The characteristics of porous aerostatic bearing are analyzed by numerical analysis, and analytic magnetic circuit model is driven for magnetic actuator to calculate preload and variation of force due to current. A 1-axis linear stage motorized with a coreless linear motor and a linear encoder was designed and built to verify this design concept. The load capacity, stiffness and preload force were examined and compared with analysis. With the active magnetic preloading actuators controlled with DSP board and PWM power amplifiers, the active on-line adjusting tests about the vertical, pitching and rolling motion were performed. It was shown that motion control far three DOF motions were linear and independent after calibration of the control gains.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.3
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• pp.7-13
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• 2019

In this paper, the principles, types and characteristics of the laser and laser soldering are introduced. Laser soldering methods for electronics, metals, semiconductors are also presented. Laser soldering is a non-contact process that transfers energy to solder joint by a precisely controlled beam. Demands for laser soldering are increasing due to bonding for complex circuits and local heating in micro joint. Laser absorption ratio depends on materials, and each material has different absorption or reflectivity of the laser beam, which requires fine adjustment of the laser beam. Laser types and operating conditions are also important factors for laser soldering performance. In this paper, the performance of Nd:YAG laser soldering is compared to the hot blast reflow. Meanwhile, a diode laser gives different wavelength and smaller parts with high performance, but it has various reliability issues such as heat loss, high power, and cooling technology. These issues need to be improved in the future, and further studies for laser micro-joining and soldering are required.

• The Korean Journal of Health Service Management
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• v.12 no.3
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• pp.131-141
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• 2018

Objectives: This study was designed to determine the effects of middle-aged men's family functionality and self-efficacy on their retirement anxiety, in order to produce methods to alleviate this anxiety, including providing basic information for devising programs that help middle-aged men get better adjusted to and increase their awareness about retirement. Methods: For data collection, the study surveyed 364 middle-aged men who were residing in B Metropolitan City from February. 10 to 25, 2017. Results: This study found that the primary factor influencing middle-aged men's retirement anxiety is self-efficacy, for which the explanatory power for the surveyed men's retirement anxiety was 52.0%. In contrast, family functionality had no effect on retirement anxiety. Conclusions: To make middle-aged men less anxious about retirement, a variety of programs must be created and implemented that help them improve their self-efficacy prior to retirement. Furthermore, these men should be provided with educational and intervention programs that facilitate their adjustment to retirement and increase their awareness about retirement.

• Journal of Power System Engineering
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• v.5 no.2
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• pp.71-78
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• 2001

Using sodium hypophosphite as reducing agent, bath composition and plating condition of electroless copper plating on plating rate have been studied. The followings were determined as optimum, bath composition; $CuSO_4\;0.025M,\;NiSO_4\;0.002M,\;NaH_2PO_2\;0.4M$, sodium citrate 0.06M, $H_3BO_3$ 0.6M, thiourea or 2-MBT $0.2mg/{\ell}$, and operation conditions; pH $9{\sim}10$ at bath temperature rage of $60{\sim}70^{\circ}C$. A small amount of nickel ion($Ni^{2+}/Cu^{2+}$=0.002/0.025) to the hypophosphite reduced solution promotes autocatalysis and continuous plating. An additive such as thiourea or 2-MBT of a small amount($0.2mg/{\ell}$) can be used to stabilize the solution without changing plating rate much. The attivation energy between $20^{\circ}C\;and\;70^{\circ}C$ were calculated to be 11.3kcal/mol for deposition weight. Plating reaction had been ceased by the adjustment of pH above 13, temperature higher than $90^{\circ}C\;and\;under\;20^{\circ}C$. Deposited surface became worse in the case of increment of bath temperature above $80^{\circ}C$.

• Journal of Nutrition and Health
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• v.43 no.3
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• pp.246-259
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• 2010

The incidence of chronic disease is continuously increasing in Korea. Especially, office workers have higher risk of chronic disease because of their dietary habit and lifestyle. The study aimed to investigate the effect of tailored nutrition counseling on improving chronic disease risk factors. Ninety-nine male workers (age $46.9{\pm}7.0$ yrs) volunteered for 12 weeks of nutrition program containing dietary intake and physical activity adjustment. Five individualized programs were performed with the main theme of weight loss (WL, n = 16), blood pressure lowering (BL, n = 34), normalizing blood glucose (GL, n = 21), lipid lowering (LL, n = 13) and reducing MS risk factors (ML, n = 15). Anthropometric data, blood-pressure, self-reported questionnaire, blood profiles were measured before and after 12weeks of nutrition education. The education program included 5 times of 1：1 interview. Compared to 0 week, anthropometric data (weight, BMI, fat, visceral fat, waist, SBP, DBP) were significantly decreased after 12 weeks (p < 0.001). Fasting blood glucose and total cholesterol were decreased (p < 0.05). The primary outcomes with individually tailored programs showed to be more effective than one general nutrition program.

• Health Policy and Management
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• v.23 no.4
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• pp.314-325
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• 2013

Background: Stem cell research competition is accelerating globally since President Obama signed an executive order, repealing Bush-era policy that limited use of federal tax dollars for embryonic stem cell research. Methods: In this paper, we conducted a comparative analysis of stem cell research policy changes in three countries, including the Human Fertilisation Embryology Act (HFEA) of UK, executive order 13,505 (removing barriers to responsible scientific research involving human stem cells) of USA, and Bioethics and Safety Act of South Korea. Debates on stem cell research are based on conflicts of fundamental beliefs that exist in the supporting and opposing coalitions. We compared regional characteristics of the advocacy coalitions in three countries and presented various factors that might be related to the policy changes. Results: The UK government, parliament, and the HFEA have sought expert consultations and public opinions to establish guidelines. UK has made social consensus through continued discussion for a long time. US President's veto power was one strongest factors influencing policy. South Korean policy was influenced by public opinion and policy brokers. Also, South Korea has not made social consensus. UK had a strong leadership and strong adjustment of coalitions but US and South Korea had not. Dr. Hwang's scandal has had one of the greatest impacts on policy decision in South Korea. Conclusion: The power of public opinion was critical in all three countries. In particular, the influence of public opinion was noticeable in South Korea. Also it turned out that in US and South Korea, the presence of a policy broker who could pursue his or her goals was the most powerful factor among the advocacy coalition factors.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.843-850
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• 2016

In this paper, we propose a digital controller design process for the interleaved type of a boost PFC (Power Factor Correction) converter which can disperse the heat of the switching devices due to the interleaved topology. We establish a mathematical model of a boost PFC converter and propose a controller design method based on the root locus. The performance of the designed controller is verified by simulations. The measurement of the input voltage, inductor currents, and the converter output link voltage are needed for the control of the converter system which consists of a power unit and a control unit where a high-performance 32-bit microcontroller is used. The adjustment of A/D conversion timing is also needed to avoid high frequency noise generated when the switches on/off. It is illustrated by the real experiments that the designed control system with the properly adjusted ADC timing satisfies the given performance specifications of the interleaved boost PFC converter in the on-board slow battery charger.

• Journal of Technology Innovation
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• v.2 no.1
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• pp.170-190
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• 1994

The importantce of a development of competitiveness in domestic construction industry is growing as some of domestic construction markets is scheduled to open to foreign competing firms with higher level of construction technology and management. A national level of competitiveness in domestic construction industry and firms are partially, but significantly, affected by a technology level and a characteristics of production pattern. The purpose of the study is mainly to analyze and identify a technology level, production pattern and a development stage of R&D activities of domestic construction industry and firms. Based on these findings the study draws on a concluding remarks and derives technology policy implications. Results of analysis in the study impliy that (1) competitiveness of domestic construction firms(industry) in terms of technology level is relatively weak as compare to that of advanced foreign competing firms, (2) degrees of substitution of capital for labor are seemed to be relatively high, (3) R&D (investment) activities of domestic construction firms are generally spread out in forms of import, adjustment and betterment, and (4) only a small number of big domestic construction firms are seemed to afford to R&D investment for research facilities and equipments, but not enough for higher level of R&D man-power. The study suggests that technology policy for construction industry should be based on a fundamental policy directions. For example the increase in size and heightened quality level of R&D man-power should be placed in a top priority in policy agenda. Sound and specific policy items should be developed for planning and design, and maintenace and inspection technology in order to lead domestic industry to compete with foreign firms with full strength.