• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2010년도 하계학술대회
• /
• pp.64-66
• /
• 2010

In this paper, we propose a temporal diversity scheme based on the vector perturbation for a multiuser multipleinput multiple-output (MIMO) broadcasting system. Our method is inspired by the fact that precoding process of the vector perturbation designed to suppress the multiuser interference causes a reduction of the transmitted signal power. In order to boost up the transmit power, we employ a non-integer based vector perturbation together with temporal transmit diversity. We show from the simulation on 10${\times}$10 multiuser MIMO system that the proposed method outperforms the epetition coded vector perturbation scheme as well as the standard vector perturbation.

• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2009년도 IWAIT
• /
• pp.94-98
• /
• 2009

In this paper, we propose a new channel estimation scheme for amplify and forward cooperative diversity with relay selection. In order to select best relay, it is necessary to know channel state information (CSI) at the destination. Most of the previous works, however, assume that perfect CSI is available at the destination. In addition, when the number of relay is increased it is difficult to estimate CSI through all relays within coherence time of a channel because of the large amount of frame overhead for channel estimation. In a proposed channel estimation scheme, each terminal has distinct pilot signal which is orthogonal each other. By using orthogonal property of pilot signals, CSI is estimated over two pilot signal transmission phases so that frame overhead is reduced significantly. Due to the orthogonal property among pilot signals, estimation error does not depend on the number of relays. Simulation result shows that the proposed channel estimation scheme provides accurate CSI at the destination.

• 한국통신학회논문지
• /
• 제27권3B호
• /
• pp.212-219
• /
• 2002

본 논문에서는 기지국에 스마트 안테나를 사용한 이동 통신 시스템에서 기지국 다이버시티를 고려하여 빔성형 가중치 결정 방법과 전력 제어 방법을 순방향 링크와 역방향 링크에 대해 제시하고 이를 Monte-Carlo 시뮬레이션 방법을 이용하여 확인하였다. 결과에 의하면 역방향 링크에서는 다이버시티 threshold가 증가함에 따라 즉, 이동국이 더 많은 기지국들과 링크함에 따라 셀의 용량이 증가하였다. 이와 반대로 순방향 링크에서는 다이버시티 threshold가 증가할수록 용량이 감소하는 것을 확인할 수 있었다. 본 논문의 결과는 스마트 안테나를 적용한 시스템의 효율적인 무선망 운용 방식 결정의 지표가 될 것으로 기대된다.

• 한국어병학회지
• /
• 제11권2호
• /
• pp.143-150
• /
• 1998

바지락 조직과 주변 환경에 있는 세균의 특성과 분포를 여러 배지와 온도 그리고 생화학적 동정 kit를 사용하여 비교 분석하였다. 장내, 갯벌, 아가미 그리고 외부체액에 있는 미생물의 집락수는 사용한 BHIA, STA 그리고 SNA 배지에 영향을 받지 않는 것으로 나타났다. 그리고 $15^{\circ}C$ 배양조건에서의 증식속도는 $25^{\circ}C$와 $35^{\circ}C$의 조건에 비해 느린 것으로 나타났으나 총 세균 집락수는 $15^{\circ}C$에서의 것이 가장 높게 나타났다. 영양배지에서 자란 세균집락을 무작위적으로 선택배지에 옮기면 조직 시료를 직접 도말 한 경우에 비해 높은 비율로 집락형성을 하는 것을 보여 주었다. API 20E와 API 20NE를 사용하여 각 장기 또는 외부에 있는 세균의 종류를 동정한 결과 바지락 조직간에는 서로 유사한 종의 분포를 보이나 주위 환경이 되는 갯벌이나 외부체액에 있는 미생물군의 종류와는 다르게 나타났다. 바지락 주위의 갯벌이나 외부체액의 미생물군은 Pseudomonas 가 주종을 이루고 있는 조직내의 미생물군에 비해서 훨씬 높은 다양성을 보여 주었다. 이러한 결과는 바지락 조직이 주위 환경중의 세균에 대한 선택적 친화력이 있음을 의미한다고 할 수 있다.

• 한국환경교육학회지:환경교육
• /
• 제25권2호
• /
• pp.149-160
• /
• 2012

This study examined the effects of reflective writing activities utilizing environmental related mass media. Two classes participated as an experimental group (n=31) and a control group (n=30). Both groups of students learned five different topics on environment, such as diversity of ecosystem, global warming, desertification, reduction of the amount of carbon, and eco-friendly behavior. The experimental group students was taught utilizing mass media about each topic and had opportunities of reflective writing about each topic, while the control group of students was taught through lectures. The results indicated that students in the experimental group represented significantly better scores on environmental worldview, environmental sensitivity, and eco-friendly behavior compared to the control group students (p<.01).

• 한국콘텐츠학회논문지
• /
• 제12권11호
• /
• pp.368-376
• /
• 2012

전통적으로 미디어 시장은 사업자수가 적고 특정 미디어의 영향력이 크기 때문에 시장집중을 엄격하게 규제하여 왔다. 하지만 미디어에 개방형 인터넷이 도입됨에 따라 미디어 규제의 근거인 희소성과 침투성 개념이 약해지고 있다. 본 연구는 미디어 융합 환경에서 기존 시장집중 규제의 문제점을 비판적으로 평가한다. 개방형 콘텐츠 유통구조에서 시장성과는 시장구조보다 사업자행위에 더 영향을 받으며, 수직결합이 서비스 혁신의 수단으로 부각되고 있고, 시장획정이 끊임없이 변하기 때문에 시장집중 측정이 어려워지고 있다. 따라서 시장집중은 단순히 사업자의 시장점유율과 같은 구조적 요인으로만 규제할 것이 아니라 시장 비효율과 다양성을 저해하는 사업자 행위를 중심으로 규제하는 것이 더 적합하다는 결론이다.

• The Plant Pathology Journal
• /
• 제29권2호
• /
• pp.144-153
• /
• 2013

Diverse bacteria are known to colonize plants. However, only a small fraction of that diversity has been evaluated for their biopesticide potential. To date, the criteria for sampling and selection in such bioprospecting endeavors have not been systematically evaluated in terms of the relative amount of diversity they provide for analysis. The present study aimed to enhance the success of bioprospecting efforts by increasing the diversity while removing the genotypic redundancy often present in large collections of bacteria. We developed a multivariate sampling and marker-based selection strategy that significantly increase the diversity of bacteria recovered from plants. In doing so, we quantified the effects of varying sampling intensity, media composition, incubation conditions, plant species, and soil source on the diversity of recovered isolates. Subsequent sequencing and high-throughput phenotypic analyses of a small fraction of the collected isolates revealed that this approach led to the recovery of over a dozen rare and, to date, poorly characterized genera of plant-associated bacteria with significant biopesticide activities. Overall, the sampling and selection approach described led to an approximately 5-fold improvement in efficiency and the recovery of several novel strains of bacteria with significant biopesticide potential.

• 방송공학회논문지
• /
• 제11권2호
• /
• pp.222-228
• /
• 2006

이 논문에서는 동일채널 간섭이 존재하는 채널 환경에서 OFDM(Orthogonal Frequency Division Multiplexing) 시스템의 수신 다이버시티 결합 방법을 제시한다. 제시한 방법에서 각 수신 안테나로부터의 수신 신호는 주파수 영역에서 부반송파 단위로 결합하며, 잡음과 간섭 전력을 고려한 MRC(Maximum Ratio Combining)를 적용한다. 잡음과 간섭 전력은 채널의 제한된 지연 확산에 기인하는 주파수 대역에서의 상관특성(coherency)을 이용하여 상관성이 큰 일정구간 이내의 부채널에 대해 잡음과 간섭 전력의 평균을 취함으로써 더 정확한 추정치를 얻는다. IEEE 802.11a 무선 LAN 규격에서 모의실험한 결과 제안방법은 간섭전력을 이용하지 않는 방식에 비해 신호대잡음비를 2-3.5dB 개선하였으며, 정확하게 잡음 및 간섭 전력을 추정한 경우에 대해 1dB 이내로 접근하는 결과를 나타내었다.

• Environmental Engineering Research
• /
• 제24권2호
• /
• pp.181-190
• /
• 2019

Constructed wetlands are improvised man-made systems, designed for adopting the principle of natural wetlands for purifying wastewater - the elixir of life. They are used widely as a cost-effective and energy-efficient solution for treating greywater generated from different tertiary treatment sources. It provides an elaborate platform for research activities in an attempt to recycle earth's natural resources. Among the several organic impurities removal mechanisms existing in constructed wetland systems, the earth's active microbial population plays a vital role. This review deals with the recent advancements in constructed wetland systems from a microbiological perspective to (effect/ devise/ formulate) chemical and physical treatment for water impurities. It focuses on microbial diversity studies in constructed wetlands, influence of wetland media on microbial diversity and wetland performance, role of specific microbes in water reuse, removal of trace elements, some heavy metals and antibiotics in constructed wetlands. The impurities removal processes in constructed wetlands is achieved by combined interactive systems such as selected plant species, nature of substrate used for microbial diversity and several biogeochemical effected reaction cycles in wetland systems. Therefore, the correlation studies that have been conducted by earlier researchers in microbial diversity in wetlands are addressed herewith.

• Journal of Sport and Applied Science
• /
• 제4권4호
• /
• pp.7-17
• /
• 2020

Purpose: This study started with interest in sport culture and is meaningful as an exploratory study to help with the basic understanding of sport culture research. Research design, data, and methodology: The approach of this study is the exploratory approach by literature reviews. This study carried out exploratory research on thinking about diversity of sports culture and the development process of sports culture by human history periods. Results: First, in thinking about cultural diversity, cultural absolutism and cultural relativism were identified. The characteristics of sports culture can identify universality, individuality and diffusion, and the attributes of sports culture included sharing, learning, accumulation, whole systematic relationship and change. Second, the characteristics of sports culture were identified by the approach of each historical era. The historical stages were divided into ancient civilizations, ancient Greece and Rome, middle ages and early modern period, and late modern period. Sports have historically been found to have a British-centered European origin or popularized in the United States. Conclusions: with the characteristics of modern sports culture, the globalization of sports culture, the prominence of sports industry and sports space marketing, and the symbiotic influence relationship of sports and mass media were examined and future directions were discussed.