• 한국전산구조공학회논문집
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• 제17권2호
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• pp.193-201
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• 2004

본 연구의 목적은 축대칭 하중을 받는 원통형 펄의 엄밀해를 구하는데 있어서, 간략하면서도 엄밀한 해를 구하는 방법을 제시하고자 하는데 있다. 이는 임의 형상의 구조해석을 위한 강력한 도구이긴 하지만 여전히 근사해석인 유한요소법에 대체될 수 있을 것이다. 이를 위해 본 논문은 반복법의 일종인 인도행렬법을 이용한 절점역계의 분배방식을 사용하였다. 원통형 쉘의 분배와 전달인자는 한성지반상의 보에 대한 미분방정식으로부터 구해진 것이다. 이러한 방법을 축대칭 집중하중과 정수압을 받는 원통형 쉘에 각각 적용해 보았고, 그 결과는 BEF 이론해와 비교할 때 만족할 만 하였다.

• Advances in aircraft and spacecraft science
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• 제2권3호
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• pp.345-365
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• 2015

This paper focuses on the design, fabrication, testing and analysis of a novel load-bearing element with energy dissipation capability. A single element comprises two von-Mises trusses (VMTs), which are sandwiched between two plates and connected to dashpots that stroke as the VMTs cycle between stable equilibrium states. The elements can be assembled in-plane to form a large plate-like structure or stacked with different properties in each layer for improved load-adaptability. Also introduced in the elements are pre-loaded springs (PLSs) that provide high initial stiffness and allow the element to carry a static load even when the VMTs cannot under harmonic disturbance input. Simulations of the system behavior using the Simscape environment show good overall correlation with test data. Good energy dissipation capability is observed over a frequency range from 0.1 Hz to 2 Hz. The test and simulation results show that a two layer prototype, having one soft VMT layer and one stiff VMT layer, can provide good energy dissipation over a decade of variation in harmonic load amplitude, while retaining the ability to carry static load due to the PLSs. The paper discusses how system design parameter changes affect the static load capability and the hysteresis behavior.

• Communications for Statistical Applications and Methods
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• 제17권6호
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• pp.899-907
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• 2010

무응답 대체(non-response imputation) 방법에 관한 많은 이론과 방법이 제안되었으며 실제 자료 분석에 이용되고 있다. 흔히 횡단면 무응답 대체를 위하여 다중대체법(multiple imputation)이 사용되고 있으며 2차년도 이상의 패널자료에는 종시점회귀대체법(cross-wave regression imputation)이 사용되고 있다. 본 연구에서는 패널자료 분석을 위하여 종시점회귀대체법의 일반형태인 시계열 대체법과 횡단면 무응답 대체법을 결합한 시계열-횡단면 다중 대체법을 제안하였다. 노동부의 매월노동통계 자료를 이용하여 제안한 방법과 기존의 종시점회귀대체법을 비교하여 우수함을 보였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.206-208
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• 2002

Metalworking fluids (MWFs) are fluids used during machining and grinding to prolong the life of the tool , carry away debris, and protect the surfaces of work pieces. These fluids reduce friction between the cutting tool and the work surface, reduce wear and galling, Protect surface characteristics, reduce surface adhesion or welding and carry away generated heat. Workers can be exposed to MWFs by inhaling aerosols (mists) and by skin contact with the fluid. Skin contact occurs by dipping the hands into the fluid, splashes, or handling workpieces coated with the fluids. The amount of mist generated (and the result ins level of exposure) depends on many factors. To reduce the potential health risks associated with occupational exposures to MWFs, it is required to establish optimum MWFs supply method and condition with minimum Quantity in all over the mechanical machining field including high speed type heavy cult ing process.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.977-980
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• 2004

Metalworking fluids (MWFs) are fluids used during machining and grinding to prolong the life of the tool, carry away debris, and protect the surfaces of work pieces. These fluids reduce friction between the cutting tool and the work surface, reduce wear and galling, protect surface characteristics, reduce surface adhesion or welding and carry away generated heat. Workers can be exposed to MWFs by inhaling aerosols (mists) and by skin contact with the fluid. Skin contact occurs by dipping the hands into the fluid, splashes, or handling workpieces coated with the fluids. The amount of mist generated (and the resulting level of exposure) depends on many factors. To reduce the environmental pollution wastes and the potential health risks associated with occupational exposures to MWFs, it is required to establish optimum MWFs supply method and condition with minimum quantity in all over the mechanical machining field including high-speed type heavy cutting process.

• 로봇학회논문지
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• 제2권4호
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• pp.353-360
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• 2007

This paper proposes the trot gait pattern generation and online control methods for a quadruped robot to carry heavy loads and to move fast on uneven terrain. The trot pattern is generated from the frequency modulated pattern generation method based on the frequency modulated oscillator in order for the legged robots to be operated outdoor environment with the static and dynamic mobility. The efficiency and performance of the proposed method are verified through computer simulations and experiments using qRT-1/-2. In the experiments, qRT-2 which has two front legs driven by hydraulic linear actuators and two rear casters is used. The robot can trot at the speed up to 1.3 m/s on even surface, walk up and down the 20 degree inclines, and walk at 0.7 m/s on uneven surface. Also it can carry over 100 kg totally including 40 kg payload.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1803-1806
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• 2003

Metalworking fluids (MWFs) are fluids used during machining and grinding to prolong the lift of the tool, carry away debris, and protect the surfaces of work pieces. These fluids reduce friction between the cutting tool and the work surface. reduce wear and galling, protect surface characteristics, reduce surface adhesion or welding and carry away generated heat. Workers can be exposed to MWFs by inhaling aerosols (mists) and by skin contact with the fluid. Skin contact occurs by dipping the hands into the fluid, splashes, or handling workpieces coated with the fluids. The amount of mist generated (and the resulting level of exposure) depends on many factors. To reduce the environmental pollution wastes and the potential health risks associated with occupational exposures to MWFs, it is required to establish optimum MWFs supply method and condition with minimum quantity in all over the mechanical machining field including high-speed type heavy cutting process.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.796-805
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• 2008

Safety Management of Korean railway industry has been rapidly changed into a risk-based approach adopted by developed countries since Railway Safety Act 2004, Rolling Stock Risk Assessment Guidance and its following regulations came into force. The fundamental requirements for the risk-based safety management is to carry out a systematic hazard identification and quantified risk analyses including cost-benefit analyses, but there has been rare a serious discussion over risk acceptance criteria and value of life in order to be able to judge the results of risk analyses and carry out cost-benefit analyses. This study presents the results of a review of risk acceptance criteria and value of life which may be adoped to Korean railway industry through the analyses with comparison of risk accepatnce principles and risk accepatnce criteria which have been already applied to other countries or other railway operators.

• 한국환경농학회지
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• 제40권3호
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• pp.203-210
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• 2021

BACKGROUND: Pesticides can persist in soil due to multiannual uses. To decrease the concerns for potential carry-over of such residues from treated soil during preceding crop cultivation to non-target crops grown in rotation, an uptake study of procymidone was conducted under the actual cultivation conditions in Korea. METHODS AND RESULTS: Procymidone was sprayed twice by foliar application with recommended and double dose according to the safe use guidelines for Korean cabbage up to 14 days before harvest. Arable land was kept fallow for 4 days after harvesting Korean cabbage, and spinach was cultivated as a succeeding crop. Initial residues in soil were 5.670-14.175 mg/kg that were degraded to 3.098-4.555 mg/kg until harvest of Korean cabbage, and then persisted at 1.026-1.300 mg/kg by spinach harvest. Procymidone residues in edible part of succeeding crops from soil uptake were in range of 0.020-0.048 mg/kg for recommended dose and 0.055-0.116 mg/kg for double dose. Root concentration factor (RCF) values of procymidone at different concentration ranged from 0.053 to 0.123, and translocation factor (TF) ranged from 0.176 to 0.768 for spinach. The value of TF was higher than RCF, indicating that the capability of translocation to shoot was relatively higher than that of root uptake and accumulation. CONCLUSION: Procymidone applied on Korean cabbage can be carried-over to spinach and detected at a level similar to MRL (0.05^T mg/kg). Therefore, this study suggests a follow-up study for establishment of plant back interval (PBI) of succeeding crops reflecting the actual agricultural conditions as this study.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.738-739
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• 2015

The main objective of this study, "Spatial Downscaling of Precipitation from GCMs for Assessing Climate Change over Han River and Imjin River Watersheds", is to carry out over Han River and Imjin River watersheds. To this end, a statistical regression method with MOS (Model Output Statistics) corrections at every downscaling step was developed and applied for downscaling the spatially-coarse Global Climate Model Projections (GCMPs) from CCSM3 and CSIRO with respect to precipitation into 0.1 degree (about 11 km) spatial grid over study regions. The spatially archived hydro-climate data sets such as Willmott, GsMap and APHRODITE datasets were used for MOS corrections by means of monthly climatology between observations and downscaled values. Precipitation values downscaled in this study were validated against ground observations and then future climate simulation results on precipitation were evaluated for the projections.