• International Journal of Reliability and Applications
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• v.10 no.2
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• pp.109-118
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• 2009

Crankshaft, the core element of the engine of a vehicle, transforms the translational motion generated by combustion to rotational motion. Its failure will cause serious damage to the engine so its reliability verification must be performed. In this study, the S-N data of the bending and torsion fatigue limits of a crankshaft are derived. To evaluate the reliability of the crankshaft, reliability verification and analysis are performed. For the purpose of further evaluation, the bending and torsion tests of the original crankshaft are carried out, and failure mode analysis is made. The appropriate number of samples, the applied load, and the test time are computed. On the basis of the test results, Weibull analysis for the shape and scale parameters of the crankshaft is estimated. Likewise, the $B_{10}$ life under 50% of the confidence level and the MTTF are exactly calculated, and the groundwork for improving the reliability of the crankshaft is laid.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.309-314
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• 2009

The unpredicted worldwide oil price makes the energy efficiency technology be more importance than any other period. The small cogeneration system is one of the most representative technology among the energy efficiency technologies, and the Stirling engine cogeneration system has been concerned and investigated due to the preferable characteristics - low toxic emission, low noise and vibration level, and the various form of fuel. A tiny, 1kW of electrical output, gas fueled Stirling engine cogeneration system was investigated. The electrical efficiency and thermal efficiency of the system were measured. The experiment was executed at an independent Stirling engine mode, independent secondary burner mode, and the combined mode. Part load characteristics of the Stirling engine cogeneration system were investigated also. With the efficiency characteristics, the $O_2$ and NOx emission characteristics were measured.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.119-126
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• 2006

Capacity spectrum method(CSM) of ATC-40(1996) and displacement coefficient method(DCM)of FEMA-273(1997) are applied to evaluate the seismic performance of bridges. In this study, equivalent response is obtained from nonlinear static analysis for the 3spans continues bridge and nonlinear maximum displacement response is calculated using CSM and DCM. Nonlinear maximum displacement response of DCM is larger than this of CSM. It is method that DCM can evaluate target displacement and ductility of structural to be easy and simple, but tend to overestimate the maximum displacement response. Therefore, this method is mainly used at preparation design level to evaluate the structural response. It is not desirable to evaluate the seismic performance using DCM.

• Journal of Industrial Technology
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• v.15
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• pp.63-70
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• 1995

This paper presents an impact control algorithm for reducing the potentially damaging effects by interation of redundant manipulators with their environments. In the proposed control algorithm, the redundancy is resolved at the torque level by locally minimizing joint torque, subject to the operational space dynamic formulation which maps the joint torque set into the operational forces. For a given pre-impact velocity of the manipulator, the proposed approach is on generating joint space trajectories throughout the motion near the contact which instantaneously minimize the impulsive force which is a scalar function of manipulator's configurations. The comparative evaluation of the proposed algorithm with a local torque optimization algorithm with a local torque optimization algorithm without reducing impact is performed by computer simulation. The simulation results illustrate the effectiveness of the algorithm in reducing both the effects of impact and large torque requirements.

• Journal of the Korean Society of Safety
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• v.28 no.4
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• pp.72-80
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• 2013

Accident prevention plan it a construction site should be analyzed and made with risk evaluation and management, from recent year, in Korea. Accidents occurred in construction site are related to all parties such as owner, main and subcontractor, labour. But analyzing some relationship between main and subcontractor is very important to estimate what risk between then are existed in a site. There are some different aspects concerning with risk management between them. Everywork has its own risk in there, This is the reason why everywork which are made by subcontractor himself should be evaluated for risk level. And main contractor should provide for subcontractor to prevent each risk at the work, all the time.

• Wind and Structures
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• v.31 no.4
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• pp.311-319
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• 2020

India is a developing nation and heavily spends on the development of wind power plants to meet the national energy demand. The objective of this paper is to investigate wind power potential of Ennore site using wind data collected over a period of two years by three parameter Weibull distribution. The Weibull parameters are estimated using maximum likelihood, least square method and moment method and the accuracy is determined using R² and root mean square error values. The site specific capacity factor is calculated by the mathematical model developed by three parameter Weibull distribution at different hub heights above the ground level. At last, the wind energy economic analysis is carried out using capacity factor at 30 m, 40 m and 50 m height for different wind turbine models. The analysis showed that the site has potential to install utility wind turbines to generate energy at the lowest cost per kilowatt-hour at height of 50 m. This research provides information of wind characteristics of potential sites and helps in selecting suitable wind turbine.

• Journal of Power Electronics
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• v.9 no.2
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• pp.173-179
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• 2009

This paper proposes a new three-phase diode rectifier system with a sinusoidal input current at unity power factor and a regulated and isolated output voltage at low level. The inherent natural wave-shaping capability of the reduced kVA polyphase transformer together with an active current wave-shaping technique results in a significant reduction of input and output filter requirements associated with switching ripple and EMI. The operation principles are described along with a design example and a comparative evaluation. Experimental results on a 1.5kW prototype are provided to validate the proposed concept.

• Annual Conference of KIPS
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• 2005.05a
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• pp.247-250
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• 2005

본 연구는 국내 공공부문 정보시스템 운영관리 수준을 측정할 수 있는 평가모델을 제시하였다. 이를 위해 국내외 선진사례, 관련 표준, 지침을 분석하여 공공부문 운영관리업무에 공통적으로 적용될 수 있는 11개 업무 분석영역을 도출하였고 각 업무영역의 평가를 위한 평가기준을 제시하였다. 그리고 이를 토대로 공공부문 운영관리 업무에 대한 수준을 측정할 수 있는 평가방안을 제시하였다. 본 연구에서 제시된 평가모델은 특정 이슈 발생시 일부 중앙부처의 요구에 따라 공공기관들을 대상으로 행하여진 단편적인 운영수준 점검 분석 활동들이 국내 실정에 맞게 운영업무 전반에 대한 종합적, 체계적 수준평가를 할 수 있는 기반을 제공하게 하였으며, 기관 내부적으로도 자체평가를 통해 운영관리업무 성숙도 제고를 위한 핵심요소를 손쉽게 식별하고 효율적인 품질향상 활동을 수행할 수 있게 하였다.

• Proceedings of the Korea Contents Association Conference
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• 2017.05a
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• pp.235-236
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• 2017

최근 제4차 산업혁명 시대가 도래함에 따라 지능정보기술은 대규모 데이터에 대한 자가학습(Machine Learning)을 통해 알고리즘 성능을 지속적으로 강화함으로써 데이터와 지식이 산업의 주요 경쟁 원천으로 부상시키고 있다. 지능정보기술은 산업전반에 구조적 대변혁을 촉발할 것으로 전망됨에 따라 전세계적으로 지능정보기술을 선제적으로 확보, 도입 및 확산하여 국가경쟁력을 제고해나가려 하고 있다. 따라서 지능정보기술을 확보하기 위한 R&D 전략수립이 무엇보다 중요해졌다. 본 조사 연구에서는 IoT, Cloud, Bigdata, Mobile, AI 등 지능정보기술 분야의 기술경쟁력 수준을 파악하기 위해 전문가 정성적 기술수준평가와 함께 특허, 논문 등 데이터기반의 기술수준평가에 대한 것이다.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.10a
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• pp.119-123
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• 2011

The application of flexo printed ONP and OCC leads to brightness decrease of deinked stock in ONP recycling system. The largest problems are due to accumulation of flexo ink & introduction of brown fibers. All these are emphasized by variations in the amount of flexo printed ONP and OCC in recovered ONP stock. Most of the brightness problems caused by flexo ink can be helped and solved by applying a proper polyelectrolytes as coagulation agent and flocculation agent. This requires exact evaluation of sedimentation or dissolved air flotation potentials of flexo ink and polyelectrolytes. Effect of bleaching chemical (H2O2) addition level on the increase of brightness of OCC included stock has been investigated by lab scale test.