• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 춘계학술대회 논문집
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• pp.88-95
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• 1997

This study provides the useful actual data instead of the experience data using in industrial fields. Especially, values of each components of cutting force are effective in the rake angle, setting angle and cutting area. Many researches have been made on the work piece materials, kinds of bite materials, rake angle, nose radius and depth of cut, but a few on the bite setting angle. In order to select optimal cutting speed, it was summarized the following results are achieved; A chieved that an affect of cutting resistance on the setting angle is a little under giving experimental conditions and therefore a worker can be choose the value of it randomly.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 학술대회 논문집 정보 및 제어부문
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• pp.111-112
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• 2008

본 논문에서는 다중경로가 무수히 많은 환경에서 다중안테나를 이용하여 고속의 데이터 전송률을 달성하기 위한 초광대역(UWB: Ultra-Wideband) 시스템의 성능 향상에 대해 연구한다. 다중 수신안테나가 제공하는 공간다이버시티와 RAKE 수신기가 제공하는 시간 다이버시티가 2PAM(Binary Pulse Amplitude Modulation) TH(Time Hopping) UWB 통신 시스템의 성능에 미치는 영향을 분석한다. 시뮬레이션 결과를 통해 다중수신안테나의 수가 증가함에 따라 TH-UWB 시스템의 BER(Bit Error Rate) 성능이 크게 향상됨을 보인다. 또한 SRAKE(Selective RAKE)에 의해 선택되는 다중경로 성분의 수가 증가할수록 시스템의 성능이 더욱 향상 됨을 확인한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.67-70
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• 2001

The tool geometry parameters and cutting process have complex relationships. Until now, numerous cutting tests were needed to acquire optimal design of end mill for the purpose of high speed machining, due to the insufficient knowledge about cutting process in high speed machining. Using various tools with different geometry, relationships between tool geometry parameter(rake angle, clearance angle, length of cutter) and cutting process(cutting force, surface accuracy, surface roughness) have been studied. Acquired data can be used to design optimal tool for high speed machining

• 한국통신학회논문지
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• 제19권3호
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• pp.560-572
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• 1994

본 논문에서는 셀룰라 CDMA 이동통신 시스팀에서 다중 경로의 페이딩 채널을 보상하기위한 레이크 수신기를 설계한다. 다중 경로 페이딩 환경에서의 임펄스 응답을 측정하기 위해 기지국에서 파일롯 채널을 통해 전송되는 short PN 부호의 부분상관함수 특성을 이용하였다. 약 10 s의 다중 경로 퍼짐을 보상하기위해 12개의 역확산 경로를 사용하였으며 보상 방법에 대한 앨고리듬을 제시하였다. 디지틀 변환되어 입력되는 수신신호를 처리하기위해 전 디지틀화된 회로를 제시하고 컴퓨터 시뮬레이션 및 타이밍 시뮬레이션에 의해 회로의 타당성을 검증한다.

• 한국통신학회논문지
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• 제30권10A호
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• pp.949-957
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• 2005

In this paper, the performances of a single-user DS-UWB system applying two simple proposed channel estimation schemes are introduced, according to the newly updated DS-UWB PHY Layer standard from IEEE P802.15.3a. The performances of error control coding, different combining schemes in selective Rake receiver for DS-UWB system are analyzed. Both of the two channel estimation schemes using data-independent structure work well in DS-UWB system with few pilot bits. For the purpose of channel estimation and reduces the number of pilot bits, we apply a pilot symbol spreaded with $2{^8}-1\;or\;2{^9}-1$ periods of m-sequence for different channel estimation schemes.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.19-22
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• 1997

The objective of this research is to use an analytical and experimental approach to develop optimal tool geometry for high speed machining. The tool geometry parameters and cutting process have complex relationships. Until now, numerous cutting tests were needed to acquire optimal design of endmill for the purpose of high speed machining, dut to the insufficient knowledge about process in high speed machining. In order to improve the cutting ability of endmill, a model for optimal cutter shape was developed to minimize resultant cutting force by combing cutting force and wear test and surface roughness test from optimized and conventional cutter with the same cutting condition. Using various tools with different geometry, relationships between the tool geometry parameter, rake angle, clearance angle, lengh of cutter have been stuied.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.581-584
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• 2003

The austenitic STS 304 stainless steel was turned to clarify the effects of tool geometry on the tool wear. The wear of TiN-TiCN-TiC-TiAlN coated tungsten carbide tool was the smallest, exhibiting larger wear in the order of Si-Al-O-N ceramic, TiN coated tungsten carbide, TiN-TiCN-TiN coated tungsten carbide, TiC-TiN cermet and M20 tungsten carbide tools at the same cutting conditions. The S-type tool of M20 with large approach angle showed the longest tool life of all tools used in this tests due to preventing the groove wear of the side cutting edge. The wear of the S-type tool with the rake angle of 15$^{\circ}$became smaller than with that of -5$^{\circ}$, but the tool with the nose radius of 0.8mm did not perform much better with increasing the rake angle.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.500-503
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• 2003

The tool geometry parameters and cutting process have complex relationships. Until now, various cutting test were needed to acquire optimal design of end mill for the purpose of high speed machining, due to the insufficient knowledge about cutting process in high speed machining. Using various tools with different geometry, relationships between tool geometry parameter (rake angle, clearance angle, length of cutter) and cutting process (cutting force, surface accuracy, surface roughness) have been studied. Acquired data can be used to design optimal tool for high speed machining

• 한국공작기계학회논문집
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• 제16권4호
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• pp.119-126
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• 2007

Generally, the machinability of materials that have a good mechanical properties is poor. The material having a high strength, high toughness in high temperature and wear resistance, it is difficult to remove a chip from workpiece. STD11 and NAK80 are kinds of these materials and these materials can be used in many industrial fields. But it is limited in use because of high cost and poor machinability. In this experimental study, the cutting of STD11 and NAK80 were used to decide the machinability and the tool shape of CBN ball end mill. From the results, the CBN ball end mill is verified that the estimated cutting edge shape of rake angle 30 degree has consistent effect on the tool wear and cutting force.

• 한국추진공학회지
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• 제14권1호
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• pp.48-55
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• 2010

본 논문에서는 엔진고공환경 시험설비의 엔진 입구 덕트에서 측정한 전압력과 정압력 및 전온도를 통해 실시간으로 공기유량을 계산하고, 압력프로파일을 이용하여 경계층 레이크를 장착하지 않았을 경우에도 공기유량을 예측할 수 있는 방법을 기술하였다. 또한, 엔진입구배관에 걸친 덕트 연결부를 통한압력손실을 예측하고, 이를 통해 공기유량을 보정함으로써, 고공환경시험설비에서의 공기유량측정의 신뢰도를 향상시키고 설비유지측면에서의 운용성을 보고자 하였다.