• Journal of Microbiology and Biotechnology
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• 제21권11호
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• pp.1143-1146
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• 2011

Metabolic engineering of plant-specific phenylpropanoid biosynthesis has attracted an increasing amount of attention recently, owing to the vast potential of flavonoids as nutraceuticals and pharmaceuticals. Recently, we have developed a recombinant Streptomyces venezuelae as a heterologous host for the production of flavonoids. In this study, we successfully improved flavonoid production by expressing two sets of genes predicted to be involved in malonate assimilation. The introduction of matB and matC encoding for malonyl-CoA synthetase and the putative dicarboxylate carrier protein, respectively, from Streptomyces coelicolor into the recombinant S. venezuelae strains expressing flavanone and flavone biosynthetic genes resulted in enhanced production of both flavonoids.

• 한국통신학회논문지
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• 제35권1A호
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• pp.71-79
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• 2010

다중채널 신호처리 알고리즘은 사용 주파수 대역의 가변성, 효율적인 전송전력 할당, 서로 다른 전송률과 대역을 요구하는 서비스 형태를 충족시키기 위한 가변 주파수 대역 변환을 요구한다. 본 논문에서는 다중채널 반송파 신호의 가변 주파수 대역 변환을 위해 시간 영역의 윈도우 함수와 DFT(Discrete Fourier Transform)를 이용한 다중채널 신호처리 알고리즘을 제안한다. 제안한 알고리즘은 기존의 주파수 영역에서 대역통과 신호처리를 하는 다중채널 신호처리 알고리즘과 달리, 시간 영역에서 윈도우 함수를 사용한 블록 신호처리를 하기 때문에 기존의 주파수 영역에서 신호처리 방식보다 연산이 간단하며 효율적인 주파수 변환을 할 수 있다. 전산모의 실험을 통해 제안한 알고리즘의 출력신호 복원과 가변 주파수 대역 변환이 효율적으로 이루어지는 것을 보였다.

• 한국위성정보통신학회논문지
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• 제5권1호
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• pp.32-37
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• 2010

다중채널 신호처리 알고리즘은 사용 주파수 대역의 가변성, 효율적인 전송전력 할당, 서로 다른 전송률과 대역을 요구하는 서비스 형태를 충족시키기 위한 가변 주파수 대역 변환을 요구한다. 다중채널 시스템의 다중 반송파 신호에 대하여 역다중화/다중화화를 통한 주파수 대역 재할당의 방식에는 개별채널 방식, 다단트리 방식, 블록 방식이 있다. 본 논문에서는 다중 반송파 신호의 채널 대역을 가변할 수 있는 향상된 개별채널 처리 알고리즘을 제안한다. 제안된 알고리즘은 CIC 필터(cascaded integrator comb filter)와 half-band필터를 이용해 데시메이션(decimation)과 인터폴레이션(inter-polaration)을 수행하며, FIR low-pass필터를 통해 다중 반송파 신호에서 각 부채널을 필터링 (filtering)하여 채널 대역을 재할당한다. 전산모의 실험을 통해 역다중화와 다중화에 의해 가변 채널 대역의 변환이 효율적으로 이루어지는 것을 확인하였다.

• 수산해양교육연구
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• 제14권2호
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• pp.129-148
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• 2002

The purpose of this study was to investigate of fishery consciousness for fisheries high school teachers. The data was collected from 61 fisheries high school teachers in Kyungbuk Province. The treatment of materials are classified by level of academic careers, teaching careers. This research evaluated percentage to the frequency of reponses to each question and carried out $\chi^2$ - test, etc. The statistically significant level accounted for p<.05 and made use of SPSS10.0. The conclusion of the study were as follows: Strategic development of fisheries high school on fishery consciousness need to program with fishery characteristic, to promote maritime affairs had better systematic publicity activities. On educational system policy need to keep consistency of occupational education policy, change of titles of school and reconstruction of department, expand of carrier guidance direction. On high self-conceit of Hsheries high school teachers need to many discussion be based program of school itself and academic society. And director and vice-principle station region of islands, etc.

• 한국통신학회논문지
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• 제24권7A호
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• pp.1005-1015
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• 1999

본 논문에서는 BPSK (binary shift keying) 방식을 사용하고 IFFT (inverse fast Fourier transform)와 FFT를 이용하여 기저 대역 변조기 및 복조기를 디지털로 구현한 MC-CDMA (multi carrier-code division multiple access) 시스템과 동일한 비트오율 (bit error rate) 성능을 갖고, 계산량과 대역폭을 줄이는 IFFT/FFT 기반의 새로운 디지털 구현 알고리즘 및 제안된 알고리즘에 적용되는 등화기 구조를 제안한다. 제안된 방법은 2개의 N/2-point 실수신호를 N/2-point IFFT와 FFT를 이용하여 동시에 변환하고 다시 복원할 수 있는 변형된 FFT 알고리즘에 기반을 두고 있다. 제안된 방법의 성능은 부가성 백색 가우시안 잡음 채널과 주파수 선택적 페이딩 채널 하에서 equal gain combiner와 maximal ratio combiner 등화기에 의한 다이버시티를 이용하여 수신했을 경우에 대한 모의실험을 통해 확인하였다.

• Current Optics and Photonics
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• 제5권4호
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• pp.409-420
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• 2021

We propose a method to synthesize a color non-hogel-based computer-generated-hologram (CGH) from light field data of a three-dimensional scene with a hologram pixel pitch shared for all color channels. The non-hogel-based CGH technique generates a continuous wavefront with arbitrary carrier wave from given light field data by interpreting the ray angle in the light field to the spatial frequency of the plane wavefront. The relation between ray angle and spatial frequency is, however, dependent on the wavelength, which leads to different spatial frequency sampling grid in the light field data, resulting in color aberrations in the hologram reconstruction. The proposed method sets a hologram pixel pitch common to all color channels such that the smallest blue diffraction angle covers the field of view of the light field. Then a spatial frequency sampling grid common to all color channels is established by interpolating the light field with the spatial frequency range of the blue wavelength and the sampling interval of the red wavelength. The common hologram pixel pitch and light field spatial frequency sampling grid ensure the synthesis of a color hologram without any color aberrations in the hologram reconstructions, or any loss of information contained in the light field. The proposed method is successfully verified using color light field data of various test or natural 3D scenes.

• 한국전기전자재료학회논문지
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• 제35권6호
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• pp.581-593
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• 2022

As energy depletion and environmental pollution problems are intensified, research has been conducted actively on alternative energy sources, an eco-friendly and continuous available energy conversion system. So has been organic solar cells whose efficiency is improved to 18.32%. The photoactive layer inside the solar cell is composed of a donor and a acceptor, and the combination of materials capable of effectively exchanging electrons greatly affects the efficiency of the organic solar cell. Accordingly, various researches have been conducted to improve the efficiency, and the maximum efficiency could be achieved by a solar cell with high carrier generation and low charge recombination characteristics through the introduction of a non-fullerene acceptor and material reconstruction. Organic solar cells are still difficult to commercialize due to their efficiency limitations and light stability, but if a photoactive layer consisting of a donor capable of efficiently absorbing long-wavelength light and an acceptor capable of forming an appropriate energy level is designed, the efficiency of the organic solar cell will reach 20%.

• 방송공학회논문지
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• 제16권2호
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• pp.207-215
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• 2011

SC-FDE(Single Carrier with Frequency Domain Equalizer) 전송 방식에서 채널의 다중경로를 통과한 신호들은 채널 지연 확산과 노이즈 영향으로 심하게 왜곡이 되거나 ISI(Inter-Symbol Interference)가 발생된다. 기존 UW(Unique-Word) 기반 SC-FDE 전송 방식중 하나인 반복적 채널 추정은 채널 길이를 안다고 가정하여 추정한 CIR(Channel Impulse Response)의 채널 길이 밖에 있는 노이즈 성분을 시간 영역에서 스무딩을 함으로써 노이즈 성분을 제거한다. 또한, 주파수 영역에서 채널 추정에 사용하는 UW를 복원하여 잔재하는 ISI 성분을 제거함으로써 채널 추정 성능을 향상시킨다. 본 논문은 채널 길이 안으로 있는 노이즈 성분 억압을 통한 채널 추정기법을 제안한다. 노이즈 성분을 억압하기 위해 시간 영역에서 추정된 CIR로 채널 길이 밖에 있는 노이즈 성분을 이용하여 노이즈의 표준편차를 추정하고 본래 신호 샘플에 영향이 안가도록 노이즈 표준편차 이득의 기준을 만든다. 추정된 노이즈의 표준편차와 이득을 이용하여 CIR 샘플들이 기준값 이하 일 때 채널 길이 안에 있는 노이즈 성분을 스무딩을 한다. 시뮬레이션 결과는 채널의 MSE(Mean Square Error)와 BER(Bit Error Rate)을 통하여 제안된 기법을 적용할 때 성능 개선이 나타남을 확인 할 수 있었다.

• Journal of Periodontal and Implant Science
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• 제35권2호
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• pp.511-524
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• 2005

The regeneration of lost periodontal tissue is a major goal of therapy. Periodontal ligament cell(PDL) is a specialized connective tissue that connects cementum and alveolar bone to maintain and support teeth in situ and preserve tissue homoeostasis. Bone morphogenetic proteins(BMPs) have shown much potential in the reconstruction of the periodontum by stimulate new bone and new cementum formation. Limitiations of BMP administration to periodontal lesions is high dose delivery, BMP transient biological activity, and low bioavailability of factors at the wound site. Gene delivery method can be alternative treatment strategy to deliver BMPs to periodontal tissue. The purpose of this study is to investigate efficiency of BMP-2 gene delivery with cell-based therapy using PDL cells. PDL cell were transduced with adenoviruses encoding either BMP-2 or Lac-Z gene. To evaluate osteogenic activity of expressed BMP-2 on PDL cells, we investigated secreted BMP-2, cellular activity, ALPase, produced mineralized nodules. To evaluate collagen scaffold as carrier for transduced cell delivery, we examined morphology and secreted BMP-2 of transducd PDL cells on it. BMP-2 transducd PDL cells produced higher levels of BMP-2, ALPase, mineralized nodules than non transduced cells. Cellular activity of transduced cells was showed similar activity to non transduced cells. Transduce cells attached on collagen scaffold secreted BMP-2 at 7day and was showed similar morphology to non transduced cells. These results demonstrated that transduced PDL cells produced biologically active BMP-2 and collagen scaffold could be carrier of transducd cells.

• BMB Reports
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• 제46권6호
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• pp.328-333
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• 2013

Many bioactive molecules like recombinant human bone morphogenetic protein 2 (rhBMP-2) have been developed for mineralized bone grafts, for which proper scaffolds are necessary to successfully apply the bioactive molecules. In this study, we tested the osteogenic efficacy of rhBMP-2 produced in-house in combination with gelatin sponge as the scaffold carrier in a rabbit radial defect model. The efficacy of the rhBMP-2 was determined by alkaline phosphatase activity assay of C2C12 cells. Two groups of ten rabbits each were treated with rhBMP-2/gelatin sponge, or gelatin sponge only. At 4 weeks, rhBMP-2/gelatin sponge grafts showed more bone regeneration than gelatin sponge grafts, as determined by X-ray radiography, micro-computed tomography, and histological analyses. At 8 weeks, rhBMP-2/gelatin sponge grafts exerted much stronger osteogenic effects. The study demonstrates the improved osteogenic efficacy of the rhBMP-2/gelatin sponge grafts in a rabbit radial bone defect model acting as a bone-inductive material.