• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.8-15
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• 2019

In this study, we synthesized a calcium sulfonate complex grease and a lithium complex grease to investigate their physical, rheological and tribological properties. The thermal stability of the calcium sulfonate was higher than $300^{\circ}C$ and the lithium complex grease was $245^{\circ}C$ in the dropping point test. In the grease viscosity measurement, the calcium sulfonate complex grease was measured as $7.0Pa{\cdot}s$ and the lithium complex grease was as $4.5Pa{\cdot}s$. Therefore, it was confirmed that the calcium sulfonate complex grease is superior to the lithium complex grease in terms of thermal stability and cohesiveness. In the 4-ball wear test, the calcium sulfonate complex grease was measured to be 0.43 mm and the lithium complex grease to 0.85 mm. In the 4-ball extreme pressure test, calcium sulfonate complex grease was measured as 620 kgf and the lithium complex grease was as 125 kgf. Therefore, it was confirmed that the calcium sulfonate complex grease is superior to the lithium complex grease in abrasion resistance and load-bearing property. It was found that the calcium sulfonate complex grease is more effective than the lithium complex grease in the lubrication at high temperature and high load.

• ETRI Journal
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• v.9 no.1
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• pp.74-83
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• 1987

최근에 컴플렉스 오브젝트 개념을 이용한 자동설계 데이터베이스 연구가 활발한데, 연구되고 있는 대부분의 설계 데이터는 그 데이터가 비교적 구조적이며 간단한 논리설계 데이터에 국한되어 왔다. 본 논문에서는 VLSI 설계의 물리적 도면(physical layout)데이터에 관해서 모든 설계 및 공정기술을 수용할 수 있도록 유연성있게 컴플렉스 오브젝트로 정의하고, 이의 오퍼레이션 및 내부구조에 관한 기법을 제시하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.3
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• pp.129-138
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• 2013

This paper is a study on Dual Tree Complex Wavelet Transform, which improved directional information for efficient image processing. Dual Tree Complex Wavelet Transform satisfies characteristics of shift invariance, and includes 6 directional information, which is more than previous Discrete Wavelet Transform. However, in images of buildings, there are many horizontal and vertical edge components. Therefore, all the high-frequency components of image are not expressed by 6 directional information subbands. This paper proposes 8-directional Complex Wavelet Transform with excellent high-frequency separation features by creating horizontal vertical($0^{\circ}$, $90^{\circ}$) subband besides 6 directional information subband of previous Dual Tree Complex Wavelet Transform. The proposed method can create and combine various directional information subbands according to features of image. Performance is evaluated by applying the method to noise removal.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2004.05a
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• pp.77-80
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• 2004

The Pinakothek der Moderne(Munich, 1996-2002, Stephan Braunfels) in planned to form the Museum Complex, with the 4th Pinakothek harmonized with Alte Pinakothek(Munich, 1826-36, L.von.Klenze) and The Neue Pinakothek(Munich, 1981, Alexander von Branca). The Purpose of this study is to find the design method of Pinakothek der Moderne for forming the Musuem Complex

• Magazine of the Korean Society of Agricultural Engineers
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• v.47 no.1
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• pp.47-53
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• 2005

• The monthly packaging world
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• s.13
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• pp.119-123
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• 1994

• Korean Architects
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• s.580
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• pp.124-127
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• 2017

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1590-1595
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• 2003

Direct drive servovalve(DDV) is a kind of one-stage valve since the rotary motion of DC motor is directly transferred to the linear motion of valve spool through the link. Since the structure of DDV is simple, it is less expensive, more reliable and offers reduced internal leakage and reduced sensitivity to fluid contamination. However, the flow force effect on the spool motion is significant such that it induces large steady-state error in a step response. If the proportional control gain is increased to reduce the steady-state error, the system becomes unstable. In order to satisfy the system design requirements, the lead-lag controller is designed using the complex method that is one kind of constrained direct search method.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.6
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• pp.170-176
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• 2005

The hydraulic cylinder is used for actuating the sluice gate which controls the volume of water in the reservoir. The locating points of hydraulic cylinder are restricted to limited space and determined to minimize the cylinder force necessary for actuating the sluice gate. Generally, the head end point of cylinder is fixed at underground and the rod end point of cylinder is connected to the gate plate when it is fully opened. Therefore there exist three parameters to be determined to minimize the cylinder force in the operation range of sluice gate. The optimal locating points of hydraulic cylinder are obtained using the complex method that is one kind of constrained direct search m method.

• Korean Architects
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• s.518
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• pp.36-41
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• 2012