• 한국통신학회논문지
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• 제30권9B호
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• pp.602-609
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• 2005

본 연구에서는 HAPS 서비스 커버리지 내의 셀 구조로서 광역 서비스가 가능하고 동일 채널 간섭을 억제하면서 주파수 이용 효율을 높이기 위해 지상 이동 통신 시스템과 유사한 셀룰러를 가정하여 매크로 셀과 마이크로 셀이 혼재하는 계층적 셀 구조의 성능을 분석하였다. 이를 위해 기존 지상 이동 통신 시스템에서 사용되고 있는 인접 셀 간섭 계수를 도입하여 매크로 셀에 미치는 마이크로 셀의 간섭영향을 분석하였다. 그 결과 HAPS는 지상 이동 통신 시스템과는 다르게 셀 간의 간섭 영향은 셀 간의 거리에는 크게 영향이 없고 마이크로 셀의 유저의 수 및 전력제어 계수 퐁에 의해 지배적으로 영향을 받으므로 이 계수를 적절히 조절한다면 매크로 셀 간에 마이크로 셀 삽입에 의한 계층적 구조를 실현할 수가 있다.

• The Korean Journal of Physiology and Pharmacology
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• 제20권5호
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• pp.533-538
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• 2016

Angiogenesis plays an essential role in embryo development, tissue repair, inflammatory diseases, and tumor growth. In the present study, we showed that endothelial nitric oxide synthase (eNOS) regulates retinal angiogenesis. Mice that lack eNOS showed growth retardation, and retinal vessel development was significantly delayed. In addition, the number of tip cells and filopodia length were significantly reduced in mice lacking eNOS. Retinal endothelial cell proliferation was significantly blocked in mice lacking eNOS, and EMG-2-induced endothelial cell sprouting was significantly reduced in aortic vessels isolated from eNOS-deficient mice. Finally, pericyte recruitment to endothelial cells and vascular smooth muscle cell coverage to blood vessels were attenuated in mice lacking eNOS. Taken together, we suggest that the endothelial cell function and blood vessel maturation are regulated by eNOS during retinal angiogenesis.

• 대한산업공학회지
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• 제34권2호
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• pp.223-234
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• 2008

Mobile multi-hop relaying (MMR) technology is being considered as a promising solution capable to enhance coverage, user throughput, and system capacity of the current wired backbone dependent wireless access networks. Since the relaying nodes do not need a wired backbone access, MMR technology offers easy and low-cost deployment, flexible cell planning, and adaptive traffic handling performance. In this paper, we investigate performance and cost effectiveness of the MMR technology deployment in the IEEE802.16j based WiBro/WiMAX systems. We first introduce standardization activities and research issues of MMR WiBro/ WiMAX systems. Since the coverage extension problem may occur in metropolitan areas as well as suburban or rural areas where user density is relatively low or moderate, we introduce several MMR topologies and analyze cost-effectiveness of MMR based coverage extension with respect to the user traffic density. Then, we argue cost effect on MMR technology deployment and throughput performance, Finally, we introduce further study issues including sectorized base station based MMR deployment approaches and the single and multi-frame structure MMR approaches.

• 한국조사연구학회지:조사연구
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• 제6권1호
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• pp.39-62
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• 2005

본 논문에서는 표본조사에서 흔히 말하여지는 ‘표본의 대표성’과 추정의 ‘일치성’, ‘비편향성’, ‘효율성’의 개념을 알아보았다. 표본의 대표성은 표집에 연관된 개념으로 조사모집단의 포함률 및 기초조사의 응답률, 표본섭외 과정의 승락률과 밀접한 관련이 있다. 그리고 추정의 일치성, 비편향성 및 효율성은 표집설계 및 추정량에 동시에 연관된 개념이다. 일치성 및 비편향성은 표본의 대표성을 전제로 한 개념인 반면, 효율성은 표본의 대표성을 전제로 하지 않는다. 표본의 대표성은 포함률, 응답률, 승낙률 등을 제고함으로써 높일 수 있다. 일치성은 관심변수의 일치성과 보조변수의 일치성으로 구분할 수 있으며, 잘 알려진 래킹비 가중법은 모집단 크기를 일치시키는 방법으로 보조변수의 일치성을 높이고자 하는 방법이다. 효율성은 표본의 대표성과는 직접적인 관련이 없으며, 층화표집에서 비례배정과 네이만 배정같은 표본배정, 그리고 사후층화 등은 모두 표본의 대표성이 만족된다는 전제 아래 추정의 효율성을 높이고자 하는 방법들이다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.117-120
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• 2000

This paper discusses solutions for forward link power allocation based on 3GPP(FDD) standardization reports and which meet the required Eb/No of forward link channels. In addition, the forward link user capacity in a mixed service environment. Cell coverage is induced from the user capacity solutions using the urban propagation model. In an urban macrocell environment, the forward link user capacity turns out to be roughly 29 and 3, respectively, for voice and data service (144 kbps) at a distance of 1 km, and in an urban microcell environment, the user capacity turns out to be Toughly 14, 4, and 2, respectively, for voice and two data services (144 kbps, 384 kbps) when the cell radius is 0.2 km.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.46-49
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• 2007

Multiple Antenna Technologies such as Multiple-Input Multiple-Output (MIMO) and Beamforming provide the increase of channel capacity and the reliability of wireless link. To obtain these advantages, WiBro, Mobile WiMAX and $4^{th}$ Generation System are employing multiple antenna technologies. There exist, however, many technical issues in considering the application of the technologies or the providing of services using them. In this paper, various technical topics are discussed and simple solutions are proposed. Beamforming has several technical issues which include coverage imbalance, difficulties in providing Multicast-Broadcast Service (MBS). In Addition, network planning is a critical point from a cell extension and initial network entry point of view. In case of MIMO, network deployment is discussed in that cellular data network such as WiBro has many repeaters. MIMO mode selection for maximizing the cell capacity is also covered.

• BMB Reports
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• 제37권1호
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• pp.35-44
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• 2004

Recently produced information on post-translational modifications makes it possible to interpret their biological regulation with new insights. Various protein modifications finely tune the cellular functions of each protein. Understanding the relationship between post-translational modifications and functional changes ("post-translatomics") is another enormous project, not unlike the human genome project. Proteomics, combined with separation technology and mass spectrometry, makes it possible to dissect and characterize the individual parts of post-translational modifications and provide a systemic analysis. Systemic analysis of post-translational modifications in various signaling pathways has been applied to illustrate the kinetics of modifications. Availability will advance new technologies that improve sensitivity and peptide coverage. The progress of "post-translatomics", novel analytical technologies that are rapidly emerging, offer a great potential for determining the details of the modification sites.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.251-252
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• 2008

Throughput and quality-of-service (QoS) over multi-cell environments are two of the most challenging issues that must be addressed when developing next generation wireless network standards. Currently, multiple-input/multiple-output (MIMO), inter-cell coordination and multi-hop relay technologies are viable options for improving channel capacity or coverage extension. Nevertheless, severe QoS degradation occurs in the outer region of multi-cells due to significant interference from neighboring cells or relay stations, thereby limiting overall performance. Therefore, we propose a scheme which adapted to hybrid relaying.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2001년도 추계학술발표회 논문집
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• pp.3-11
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• 2001

Fundamental studies at the CSIRO division of Wool technology and ICI on the diffusion of dyes into wool〔1,2〕have let to development of a new approach to wool dyeing. In this method, the cell membrane complex of wool is modified before dyeing by treatment under mildly alkaline conditions with a special chemicals. Wool pretreated with ethoxylated quaternary ammonium salt has an increased rate of dyebath exhaustion and dye penetration early in the dyeing cycle. This enables the treated material to be dyed below the boil for a similar time to the conventional cycle. This technique can be used on untreated and shrinkresist-treated wool and wool/nylon blends. In addition to good macro-levelness and excellent coverage of tippiness, the low temperature dyeing process give higher exhaustion levels of dyestuffs and insect-resist agent and hence cleaner effluent liquors, compared with conventional dyeing process. Low Temperature Dyeing process cause significantly less fiber damage than conventional way. The reduction in damage is reflected in improved processing performance of the dyed wool.

• 한국통신학회논문지
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• 제41권3호
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• pp.301-303
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• 2016

본 논문은 모바일 사용자의 신뢰성 향상을 위하여 기지국의 범위 내에 소형 기지국들을 추가적으로 사용하여 전송 다이버시티 이득을 제공하는 방법을 제안한다. 기존의 기지국은 기지국 셀 내에 위치한 소형 기지국들을 중계기로 이용한 협력 통신 기법을 적용하고 전송 다이버시티 이득을 얻기 위한 신호를 구성한다. 모바일 사용자는 결과적으로 기존의 기지국과 릴레이 역할의 소형 기지국들로부터 다중의 채널을 통하여 신호를 수신 받을 수 있게 되고, 이때 수신된 신호들은 전송 다이버시티 기법이 적용됨으로써 신뢰성이 크게 향상 될 수 있다.