• Journal of Life Science
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• v.19 no.1
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• pp.58-64
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• 2009

This study was conducted to know the molting sequence and the aging points of flight feathers of steller's sea eagles (Haliaeetus pelagicus). For this study, two captive immature steller's sea eagles raised at the Ornithology Laboratory attached to Kyungsung University were surveyed for five years from Nov. 2000 to Nov. 2005. The survey indicated that the first molting began in July of the second year, and the primaries of P1-3, the secondaries of S18-19 (female), S17-18 (male), and S1 and S4 were replaced by one-time with second generation feathers. Generally molting stopped during the winter period, but a few feathers continued to molt during the winter. The two secondaries of S18-19 (female) and S17-18 (male) always molted every year but some of the juvenile secondaries (male: S10, S11, etc) retained for 2 or 3 years. In the molting order of primaries, the first molting started at P1 and it proceeded to P10 of outside. In the secondaries, the first molting started at S17(male) and S19(female), and it proceeded to outside. After that molting it started at S1 and proceeded to inside. In the other secondaries, the pattern of molting which proceeded in the mid-part of the secondaries was usually beginning in several different points at the same time. The molting seemed as if it depends on both the conditions of the individuals and the environment, so it was very difficult to explain the molting pattern in the mid-part of the secondaries. The longer quills (P7, P8) required for more than 68 days to develop. In the comparison of the length in the remiges between the first and the second generation feathers, the first generation feathers were the larger than that of the second. And the reduction of the length between the second and the third generation feathers was a few. The reduction of the length between the third and the fourth generation feathers was slight. The juvenile primaries were dark brown with a whitish base, which could be observed until the second or the third generation feathers (in their third or fourth winter plumage).

• Korean Journal of Environment and Ecology
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• v.22 no.4
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• pp.435-441
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• 2008

This study conducted a survey on the moulting sequence subsequent to age of Haliaeetus pelagicus raised in captivity at the Ornithology Laboratory attached to Kyungsung University for about six years from November, 2000 until July, 2006. The survey indicated that the moult of rectrices usually began in July and continued until April of the next year and most of the rectrices were replaced by one-time moult. Usually, about two thirds of the tail feathers were replaced while the rest were replaced no later than April of the next year, and the moult also continued during the wintertime. The total number of rectrices was 14, and the moult progressed alternately on a systematic basis. The progress of the moult for female & male was made on four stages and three stages respectively and the characteristic shown on every stage of the moult was that the left & right tail feathers progressed symmetrically and not until one stage of progress almost completed did the next stage began. The color of the juvenile steller's sea-eagle was dotted with black spots on its original white color and there existed regular black belt on its feather's fringes; however, it was difficult to identify its age by tail feathers only because there was almost no difference in color between feathers ranging from the first to the third generation(1st-3rd summer feathers). In addition, this research took the different amounts of black-speckled pattern appearing by individual into consideration. There existed slight black speckles in white color feathers of the fourth generation(the 4th summer feathers) while showing a big difference compared to the 3rd generation feathers. The 5th generation feathers[the 5th summer feathers]were found to be equipped with perfect tail feathers having virgin white of a steller's sea-eagle after completing its 4th molt. When observing a steller's sea-eagle in the open air, it is necessary for an observer to have a deliberate examination in judging its age belonging to the 1st-3rd generation feathers, and it is considered that the changes of other parts of feathers should be also observed besides tail feathers.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.225-230
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• 2002

현재 미 해군에서 개발 중인 DD21은, 미 해군의 해상 전투력 구조의 핵심인 이지스급 함정을 제외한 DD-963급 구축함과 FFG-7급 프리깃 함의 교체함으로서, 연안전에 대한 새로운 특수 임무에 적응할 수 있게 많은 학자들에 의해 연구되고 있는 차세대 구축함이다. 즉, DD21은 기존 이지스 함정에 부가하여 대지전(Land Attack)과 대기뢰전을 포함한 다목적의 기능을 발휘하면서 전투원의 스마트(Smart), 배치와 장비와 기구의 자동화와 기계화를 통한 함정과 함체의 스텔스(Stealth)화로 유지비와 초기 투자비를 최소화시킨 함정이다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.12
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• pp.1017-1024
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• 2012

The aerodynamic design and analysis on advanced propeller with blade sweep was performed for recent turboprop aircraft. HS1 airfoil series are selected as a advanced propeller blade airfoil. Adkins method is used for aerodynamic design and performance analysis with respect to the design point. Adkins method is based on the vortex-blade element theory which design the propeller to satisfy the condition for minimum energy loss. Propeller geometry is generated by varying chord length and pitch angle at design point of target aircraft. Advanced propeller is designed by apply the modified chord length, the tip sweep which is based on the geometry of conventional propeller. The aerodynamic characteristics of the designed Advanced propeller were verified by CFD(Computational Fluid Dynamic) and evaluated to be properly designed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.1058-1060
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• 2005

현재 통신 서비스 및 인터넷 서비스들은 각기 독립적인 형태의 서비스를 재공하고 있으며, 고유의 서비스 체계를 유지하면서 발전해 왔다. 그러나 이러한 서비스들은 향후 통합 및 융합과정을 거처 차세대 네트워크 망 즉, NGN(next generation network)에 통합되어 나가게 될 것이며 기존의서비스에 다양한 서비스를 부가하여 새로운 서비스가 창출 될 것이다. 된 논문은 이러한 추세를 고려하여, NGN에서 요구되는 언제 어디서나 사용자에 다양한 서비스를 제공할 수 있는 서비스인 텔레매틱스에 대한 NGN 서비스 시나리오를 보일 깃이다. 텔레매틱스는 정보기술과 자동차기술의 융합으로 이루어진 서비스로 위치측정시스템과 무선통신량을 이용하여 교통정보, 응급구조 구난, 인터넷 이공 및 전화 등 다양한 서비스를 제공을 수 있는 시스템으로 차세대 네트워크 서비스로 각광 받고 있다. 그리나 아직까지 NGN에서의 활용에 대한 연구는 이루어지고 있지 않은 실정으로 본 논문에서는 텔레매틱스에 대한 NGN 망 및 기존의망과의 접속 시나리오와 서비스 시나리오에 대할 방법을 제안 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.135-135
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• 2004

21세기 정보화시대에 미디어의 발전은 고저장밀도를 요구하는 정보저장 장치의 개발을 필요로 하게 되었고, 현재 정보저장 장치의 주류를 이루는 magnetic recording 방식에 의한 HDD는 향후 5년 이내에 초자성한계 (super paramagnetic limit)라는 물리적 현상에 직면하여 더 이상 발전이 어려울 깃이다 따라서 이러한 한계를 극복하기 위한 여러 기술 증 Scanning Probe Microscope (SPM)을 이용한 차세대 탐침형 정보저장 기술은 미세한 끝단 반경을 가지는 탐침과 표면의 상호작용을 이용하여 정보를 기록/재생하는 기술로써 수십 nm 크기의 bit를 형성하여 Tbit/in$^2$ 이상의 높은 저장밀도를 가질 수 있으므로 현재 가장 상용화될 가능성이 높다.(중략)

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.3
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• pp.57-68
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• 2012

In this study, designs of the high efficiency composite propeller blade for a high speed turboprop aircraft, which will be used for a next generation regional commercial aircraft in Korea, are performed. Both the vortex theory and the blade element theory are used for preliminary aerodynamic design and performance analysis of the propeller. Then the aerodynamic design result is confirmed through performance analysis using a commercial CFD code, ANSYS. The carbon/epoxy composite materials is used, and the skin-spar-foam sandwich type structure is adopted for improvement of lightness and structural stability. Finally, it is investigated that the proposed propeller blade has high efficiency and structural safety through both aerodynamic and structural analysis and experimental test of a prototype propeller blade.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.253-258
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• 2012

In this study, designs of the high efficiency composite propeller blade for a high speed turboprop aircraft, which will be used for a next generation regional commercial aircraft in Korea, are performed. Both the vortex theory and the blade element theory are used for preliminary aerodynamic design and performance analysis of the propeller. Then the aerodynamic design result is confirmed through performance analysis using a commercial CFD code, ANSYS. The carbon/epoxy composite materials is used, and the skin-spar-foam sandwich type structure is adopted for improvement of lightness and structural stability. Finally, it is investigated that the proposed propeller blade has high efficiency and structural safety through both aerodynamic and structural analysis and experimental test of a prototype propeller blade.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.1
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• pp.41-51
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• 2001

In this paper, we presented that the performance of the TCM(Trellis Coded Modulation) using the Euclidean distance is better than that of the convolutional code using the hamming distance under the same bandwidth efficiency. And the TCM DECODER for next generation mobile communication replacing the using convolutional decoder is implemented. Also, for the implementation of the TCM DECODER, the convolutional decoder and the TCM decoder were made by C-language and simulated under AWGN channel with respect to the hard decision and the soft decision. So we proved that performance of the TCM is better than that of the convolutional code. From this result, TCM DECODER, of which constraint length is 3, 5 or 7 and which use the soft decision method, was implemented using the AHDL(Altera Hardware Description Language) and fortified using the Max+plus H version 8.2 of Altera corporation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.4
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• pp.336-343
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• 2014

Modern advanced-turboprop propellers are required to have high structural strength to cope with the thrust requirement at high speed. The high stiffness and strength carbon/epoxy composite material is used for the major structure and skin-spar-foam sandwich structural type is adopted for advantage in terms of the blade weight. As a design procedure for the present study, the structural design load is estimated through investigation on aerodynamic load and then flanges of spars from major bending loads and the skin from shear loads are sized using the netting rule and Rule of Mixture. In order to investigate the structural safety and stability, stress analysis is performed by finite element analysis code MSC. NASTRAN. It is found that current methodology of composite structure design is a valid method through the static structural test of prototype blade.