• 한국산업보건학회지
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• 제22권1호
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• pp.82-90
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• 2012

Objectives: This study was performed to provide workplaces with political guidelines that apply international CMRs (Carcinogens, Mutagens, Reproductive toxins) information to Public Notice of TLVs (Threshold Limit Values). We analyzed information supply status about CMRs of international agencies and compared substances for which TLVs are set in KMoEL (Ministry of Employment and Labor in Korea). Methods: We referred to the reliable literature about classification criteria of CMRs corresponding to UN GHS (Globally Harmonized System of classification and Labeling of chemicals) and Public Notice No. 2009-68 'Standard for Classification, Labeling of Chemical Substance and Material Safety Data Sheet' in KMoEL. The classification system of CMRs in professional organizations (IARC, NTP, ACGIH, EU ECHA, KMoEL, etc.) was investigated through the internet and literature. Conclusions: 191 chemical substances among total 650 substances with TLVs are classified as carcinogens. Also, 43 substances classified as mutagens, and 44 as reproductive toxicants. These results suggest that the information of CMRs in Public Notice of TLV will be reorganized to 191 carcinogens, 43 mutagens, and 44 reproductive toxicants.

• 한국정밀공학회지
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• 제1권3호
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• pp.71-84
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• 1984

This paper examined strain distribution and radius of curvature of the bulge by finite element method and investigated limit polar thickness strain to predict the formability of sheet metal as we substituted effective strain and the radius of curvature obtained by FEM into instability condition equation successively. In experiment, the radius of curvature and limit polar thickness strainwere obtained by Moire method. Also, a concent- ric set of photogrid circles was used to measure the strain of arbitrary point and mild steel was used as material. This results obtained are as follows: 1) The radius of curvature obtained by FEM is in good agreement with the Moire experimental value. 2) The polar thickness strain is getting larger as the inside is approached from the edge. This means that fracture occurred near the ploe. 3) The circumferential strains agree closely with the meridian strains and the polar thickness strain is about twice the circumferential (or meridian) strain. This result agrees with the fact that anisotropy coefficient (R-value) obtained by tensile test is about one. 4) The theoretical results of limit polar thickness strain obtained by authors' method are better agreement with experimental results than other theoretical results. Therefore, we can better predict the formability of sheet metal with authors' method.

• 한국해안·해양공학회논문집
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• 제33권6호
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• pp.293-297
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• 2021

소파블록 피복제 제체의 한계상태설계법 개발을 위해 하중저항계수 보정을 수행하였다. 실제 시공된 소파블록 피복제 제체의 설계자료를 분석하여 신뢰성해석을 수행하였으며 목표신뢰성지수에 따른 부분안전계수와 하중, 저항계수를 차례로 산정하였다. 최적화기법을 통해 한계상태설계법 개발을 위한 하중계수와 저항계수를 도출하였다. 최종 하중저항계수를 이용하여 방파제를 재설계하였으며 목표수준의 신뢰성지수를 상회하는지 검증하였다. 해외기준의 하중저항계수와 본 연구에서 구한 하중저항계수를 비교하였다.

• 전력전자학회논문지
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• 제27권5호
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• pp.438-445
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• 2022

Blade efficiency decreases when the rotor speed is kept constant even though the wind speed is higher than the rated value. Therefore, a speed controller is used to regulate the rotor speed in the high-wind-speed region. In stall-blade wind turbine, the role of the speed controller is important because precise aerodynamic regulation is unavailable. In this study, an effective parameter design method of a PI speed controller is proposed to limit the speed overshoot of a type 4 wind turbine with stall blades even though wind gust occurs. The proposed method considers the efficiency characteristics of the stall blade and the mechanical inertia of the wind turbine rotor. It determines the bandwidth of the speed controller to comply with the speed limit during generator speed overshoot for the worst case of wind gust. The proposed method is verified through intensive simulations with a MATLAB/SIMULINK model and experimental results obtained using a 3 kW MG set of wind turbine simulator.

• Nuclear Engineering and Technology
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• 제53권1호
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• pp.351-356
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• 2021

Korean nuclear power plants (NPPs) have various radiation protection programs to attain radiation exposure as low as reasonably achievable (ALARA). In terms of ALARA, this paper provides a comprehensive overview of administrative dose control for occupationally-exposed workers in Korean NPPs. In addition to dose limits, administrative dose constraints are implemented to resolve an inequity of radiation exposure in which some individuals in NPPs receive relatively higher doses than others. Occupational dose constraints in Korean NPPs are presented in this paper with the background of how those values were determined. For pressurized water reactors, 80% and 90% of the annual average limit for an effective dose, 20 mSv/y, are set as the primary and secondary dose constraints, respectively. Pressurized heavy water reactors (PHWRs) have also established the primary and secondary dose constraints corresponding to 70% and 80% of the effective dose limit, and additional constraints for tritium concentration are provided to control internal exposure in PHWRs. Follow-up measures for exceeding these administrative dose constraints are also introduced compared to exceeding the dose limits. Finally, analysis results of dose distributions show how the implementation of administrative dose constraints impacted the occupational dose distributions in Korean NPPs during the years 2009-2018.

• 한국화재소방학회논문지
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• 제15권4호
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• pp.1-9
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• 2001

The purpose of this study is to set up disaster prevention plan and risk assessment system considering combustion velocity at traditional housing zone. The combustion velocity analysis could contribute to build in disaster prevention technique through the potential risk analysis of the area, such analysis also able to set up comprehensive disaster prevention management system. Following results have achieved through the combustion velocity calculation. \circled1 The combustion velocity was calculated in order of the below winds, the above winds and the side winds. \circled2 It must be careful to set up disaster prevention plan in case of the below winds. \circled3 The combustion velocity was calculated at the density Bone where neighboring Distance and Length was small. \circled4 It proved that factors of each parameter not mostly effect to analyse the combustion velocity in limit of the 30 minutes after ignition. \circled5 At the density zone where Distance and Length is small the duration of transfer to neighboring house takes up to 4 minutes, it is required to set up of emergency response plan to minimize the fire dispersion.

• 대한수학회보
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• 제50권1호
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• pp.175-184
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• 2013

In this paper, the reverse Bonnesen style inequalities for convex domain in the Euclidean plane $\mathbb{R}^2$ are investigated. The Minkowski mixed convex set of two convex sets K and L is studied and some new geometric inequalities are obtained. From these inequalities obtained, some isoperimetric deficit upper limits, that is, the reverse Bonnesen style inequalities for convex domain K are obtained. These isoperimetric deficit upper limits obtained are more fundamental than the known results of Bottema ([5]) and Pleijel ([22]).

• 대한전자공학회논문지
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• 제10권6호
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• pp.45-55
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• 1973

본 논문은 한개의 터널다이오드로 구성된 시간에 무관한 비선형 회로를 논한다 부저항 소자로 구성된 비선형 회로의 해를 구하기 전에 비선형 소자의 정특성을 어떤 함수로 표시할 필요가 있다. 최소 자승법에 의해서 정특성을 표현하는 근사 다항식 커브를 구했다. 비선형 회로를 해석하기 위해서는 우선 그 회로에 관한 상태방정식이 설정되면 프레딕터·코렉터 방법에 의해서 해를 구할수 있다. 최종적으로, 비선형 회로의 안정도와 발진 조건을 논하기 위해서 limit cycle을 점철했다.

• 수산경영론집
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• 제42권3호
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• pp.95-107
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• 2011

The Comprehensive Measures for a soft landing of Household Debts affecting the credit service of Fisheries Cooperative (FC) have been known to the public in June 2011. Its essential points are as follows: 1) Abolition of Tax-free Regulation, 2) Set limit of loans, etc. per person, 3) Introduce leverage regulations for credit-specialized financial sector i. e. FC, 4) Gradually strengthen loan-loss reserve requirements for card-loan and other credit loans. However, the Financial Policy Measures seem to pay no attention to the Cooperative's Values, Principles and Identity. In this paper, emphasis is be placed on the task of the regulators i. e. Financial Services Commission and Financial Supervice Service to lift the Financial Measures negatively affecting the operation of fund of FCs, and on the establishment of Cooperative identity in order to further develop FCs.

• 한국공작기계학회논문집
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• 제12권3호
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• pp.17-24
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• 2003

One of the most important performance criteria related to the gain tuning of controller for CNC machining center is the contour error. This study analyzed circular error by the axis-matched and mismatched cases. To reduce ellipse and radius error, it is necessary to set the gain for each axis to be same bandwidth and high response. Based on the analysis in the frequency domain, we simulate feed system by mathematical model and then predict bandwidth of each axis. For analysis of structure vibration while the each axis is moving, we try the various of measuring method and position loop is improved by jerk limit.