• Journal of Advanced Marine Engineering and Technology
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• v.37 no.2
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• pp.178-182
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• 2013

In mining and its similar industries, compact excavators are used commonly in narrow working spaces, of which bucket must be rotated essentially. Considering of those applications, many kinds of the compact excavators have been developed, but any stress evaluation of bucket rotating part had not been attempted. In this study, using of the finite element method and Spare solver, stress analysis has been performed on the bucket rotating parts and its adjacent parts of compact excavator, with using an excavation stress model, in various directions and positions. Resultantly, it has been defined that stress of connector in the rotating part is a little higher, due to its shape, than those remained parts of which stress are shown equally as 1 MPa. Especially in the moving parts, the stress of bucket pin and rotating pinion gear has been calculated as 7.7 MPa and 40 MPa respectively.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.229-238
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• 2013

This study was conducted to analyze on the operational cost of logging operations in the whole-tree logging operation system by tower-yarder and swing-yarder, and in the cut-to-length logging operation system by excavator with grapple in order to spread efficient logging operation technique and to establish the logging operation system. In the results of the analysis of operation cost, in case of the whole-tree logging operation system, the operation cost was 2,099 won/$m^3$ in felling by chain saw, 28,286 won/$m^3$ in yarding by tower-yarder, 18,265 won/$m^3$ in yarding by swing-yarder, 18,939 won/$m^3$ in bucking by excavator with grapple and chain saw, 20,484 won/$m^3$ in forwarding and accumulation by wheel type mini-forwarder, 12,701 won/$m^3$ in forwarding and accumulation by excavator with grapple and small forwarding vehicle. In case of the cut-to-length logging operation system, the operation cost was 10,160 won/$m^3$ in felling and bucking by chain saw, 7,567 won/$m^3$ in cut-to-length extraction by excavator with grapple, 6,982 won/$m^3$ in branches and leaves extraction by excavator with grapple, 3,040 won/$m^3$ in the operation road construction by excavator with grapple, 20,484 won/$m^3$ in forwarding and accumulation by wheel type mini-forwarder, 12,701 won/$m^3$ in forwarding and accumulation by excavator with grapple and small forwarding vehicle.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2017.05a
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• pp.423-449
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• 2017

그간 다양한 제조업에서 발생한 후발국가의 '추격'에 대한 연구가 다수 이루어졌다. 특히 최근에는 추격을 위한 기회의 창 관점에서 새로운 후발국가에 의한 추격의 반복과 그에 따른 산업 시장 주도권의 이전을 논의하기 위한 '추격 사이클' 이론이 제시되어 몇몇 산업과 시장에서 발생한 주도권 이전에 관한 실증 연구가 등장하기 시작하였다. 그러나 산업 시장 주도권 이전 현상은 이미 광범위하게 일어나고 있으며, 이에 대한 논의의 심화와 이론의 발전을 위해서는 심층적인 실증 연구가 지속적으로 등장할 필요가 있다. 이에 따라 본 연구에서는 중국 굴삭기 시장에서 발생한 우리나라에서 중국으로의 주도권 이전의 원인과 그 과정을 추격 사이클 이론에서 제시한 세 가지 기회의 창, 즉 기술적 기회의 창, 수요적 기회의 창, 그리고 정책 제도적 기회의 창과 이에 대한 우리나라와 중국 굴삭기 산업의 전략적 대응 간 결합을 통해 고찰하였다. 먼저 기술적 기회의 창 관점에서는 굴삭기 아키텍처의 모듈화가 완제품 생산에 필요한 기술적 지식의 장벽을 낮추고 기술 학습 속도를 높임으로써 중국 굴삭기 산업의 추격과 시장 주도권 확보에 긍정적인 영향을 미친 것으로 나타났다. 한편 중국 정부의 수요산업(건설업) 육성 정책과 핵심 부품의 수입 관세 철폐, 공용 부품 표준화 정책과 같은 정책 제도적 기회의 창과 이에 대한 중국의 적극적 대응 또한 시장 주도권 이전에 긍정적인 영향을 미침을 확인하였다. 마지막으로 수요적 기회의 창의 관점에서는 2010년 이후 미니 소형 세분시장의 급속한 확대에 대한 중국의 전략적 대응이 산업 주도권 이전에 큰 영향을 미침을 발견하였다. 본 연구는 추격 사이클 이론에 대한 새로운 실증을 제시함으로써 향후 본 이론의 발전에 기여할 것으로 기대된다. 또한 본 연구 결과는 중국의 추격에 직면하였거나 이미 주도권을 넘겨준 우리나라의 제조업의 위기 극복 및 지속가능한 성장을 위한 전략과 정책 수립의 중요한 지침으로 널리 활용될 것으로 기대된다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.59-60
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• 2007

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.717-718
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• 2014

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.488-489
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• 2014

This paper is a case study for the reduction of excavator Radiated noise. The main purpose of the study is to reduction noise for the cooling fan and hydraulic line which is main noise source of the excavator. Recent, noise regulations for the construction equipment is becoming stricter. Compare to past excavator drivers requirements for noise level demanding are becoming more and more. Therefore, this progress is an important role in determining the quality of the excavator.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.2
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• pp.119-126
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• 2008

In this study, the characteristics of the hydraulic control system with bleed-off center type of a compact excavator were analyzed using developed analysis program. From the parametric analysis, the effects of each factor were revealed. Through the simulation with varying parameters, the system parameter effects on the controllable region and the pump pressure and load pressure variations were studied. The results were compared with the experimental ones. The results and discussions of the present paper could aid in the performance improvement of a hydraulic control system of a compact excavator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.240-246
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• 2019

The noise generated by construction machinery operating at construction sites is a major cause of environmental disputes with nearby residents. To reduce construction site noise, low noise construction machinery and low noise methods are recommended to be used first. In addition, the possible noise should be predicted and preventive measures suitable for the noise source should be taken. This study analyzed the sound power level of an excavator, which is used most frequently at construction sites. The sound power level of 297 excavators sold in Korea after 2008 were analyzed and the sound power level was classified according to the type, output (kW), and production site of the excavator engine based on the measured data. As a result, the sound power level decreased by 1 dBA depending on the change in engine type and the sound power level increased by approximately 3 dB (A) when the engine output was doubled. In addition, the sound power level was low in small-sized products of less than 55 kW for overseas products and medium and small-sized products of 55 to 104 kW for domestic products.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.344-355
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• 2012

This study was conducted to analyze on the operational time and productivities of logging operations in whole-tree logging operation system by tower-yarder and swing-yarder, and in cut-to-length logging operation system by excavator with grapple in order to establish the efficient logging operation system and to spread logging operation technique. In the analysis of operational time, in case of whole-tree logging operation system, the felling time was 46.6 sec/cycle by chain saw, the yarding time was 480.6 sec/cycle by tower-yarder, the yarding time was 287.4 sec/cycle by swing-yarder and the bucking time was 155.14 sec/cycle by chain saw. In case of the cut-to-length logging operation system, the felling and bucking time was 225.65 sec/cycle by chain saw, the cut-to-length extraction time was 4,972 sec/cycle by excavator with grapple, the branches and leaves extraction time was 3,143 sec/cycle by excavator with grapple. The forwarding time was 4,688 sec/cycle by wheel type mini-forwarder, the forwarding time was 2,118 sec/cycle by excavator with grapple and small forwarding vehicle. In the analysis of operational productivities, in case of whole-tree logging operation system, the average felling performance was $57.89m^3/day$ by chain saw, the average yarding performance was $20.3m^3/day$ by tower-yarder, $31.55m^3/day$ by swing-yarder respectively, the average bucking performance was $20.3m^3/day$ by chain saw. In case of the cut-to-length logging operation system, the average felling and bucking performance was $11.96m^3/day$ by chain saw, the average cut-to-length extraction performance was $34.75m^3/day$ by excavator with grapple, the average branches and leaves extraction performance was $37.66m^3/day$ by excavator with grapple, the average length of operation road construction was 73.8 m/day by excavator with grapple. The average forwarding performance by wheel type mini-forwarder and the average forwarding performance by excavator with grapple and small forwarding vehicle was $15.73m^3/day$ and $65.03m^3/day$, respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1043-1044
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• 2012