IP-TV 서비스를 위한 EPON 시스템에 관한 연구

李淳和,金長福 弘益大學校 科學技術硏究所 2005 科學技術硏究論文集 Vol.16 No.-

In recent years the development of high-speed metropolitan networks has exploded, more and more households have access to such a network. In the case of IPTV there exits a need for an efficient way of transporting digital video over an Internet like network in a broadcast fashion. IP multicast is proven way to efficiently transmit multimedia content to a selected set of receiver. An IPTV stream consists of video, audio, and additional information. In this paper we present the method of improving the session protocol and The HGW(home gateway)'s buffer scheduling strategy for an apartment authenticate the highest FTTH class in EPON system.

하천수의 농약 유출 특성에 관한 연구

이순화,박영규,이철희,신현진 대한환경공학회 1996 대한환경공학회 학술발표논문집 Vol.1996 No.12

국내 공공안전재난구조 무선통신을 위한 주파수 소요량 산출

이순화,윤재선,김장복,임승각 한국인터넷방송통신학회 2011 한국인터넷방송통신학회 논문지 Vol.11 No.4

효율적이고 체계적인 재난대응을 위해 공공안전재난구조 무선통신에서도 광대역 멀티미디어 서비스들의 요구가 점차 증대되고 있다. 최근 국내에서도 디지털 텔레비전 전환에 따른 여유 주파수를 공공안전재난구조 무선통신 주파수에 추가 할당할 수 있는지 여부를 방송통신위원회에서 검토하고 있다. 따라서 본 논문에서는 ITU-R M.1390에서 권고한 주파수 산출 방법론을 기반으로 하여 국내 공공안전재난구조 무선통신을 위한 입력 파라미터를 정의하고 요구되는 주파수 소요량을 산출하였다. For Effective and systematic response to disasters, needs of broadband multimedia services in wireless communication of PPDR(public protection and disaster relief) is increasing gradually. Recently in Korea, by the digital television transition, Korea Communications Commission is considering whether the freed spectrum can assign additional spectrum of PPDR or not. In this paper, we were defined the input parameters, were estimated the spectrum of requirements for Korean wireless communication of PPDR based on M.1390 ​​methodology recommended by ITU-R.

EPON의 동적대역폭할당을 위한 ONU와 OLT 설계

이순화,이종호,김장복 한국통신학회 2004 韓國通信學會論文誌 Vol.29 No.2B

EPON(Ethernet Passive Optical Network)은 FTTH(Fiber To The Home)구성에 경제적인 기술로서, 차세대 가입자망 구성중 하나로 활발히 연구되고 있다. EPON은 Ethernet을 기반으로 하고 있기 때문에 QoS(Quality of Service) 지원을 위해서는 가입자에게 동적대역폭할당을 적용해야 한다. 최근 EPON 표준화에 대해 활발히 연구하고 있는 EFM SG 방향 역시 동적대역폭할당으로 결정한바 있다. 따라서 본 논문에서는 EPON의 MAC(Media Access Control) 프로토콜인 MPCP(Multi Point Control Protocol)에서 DBA(Dynamic Bandwidth Allocation)의 구현에 적합한 ONU(Optical Network Unit) 버퍼 스케줄링 알고리즘(AIWFQ)과 OLT(Optical Line Terminal)의 DBA 전략(Class-based FCFS)을 설계한다. 본 논문에서 제안한 알고리즘의 구현을 위해서 OPNET 시뮬레이션 도구를 이용하였으며, 단대단 처리지연 시간과 버퍼크기를 측정하여 EPON 시스템의 모델로 활용할 수 있는 방안을 제시한다. The EPON has been actively studied as one of the access networks for the economic configuration of FTTH. The EPON must support the dynamic bandwidth allocation to the subscribers in order to support the QoS due to its base on Ethernet technology. EFM SG, which is actively working for the standardization of EPON, also recently decided to select DBA. Therefore in this paper, we designed a ONU buffer scheduling algorithm (AIWFQ) and a scheme of DBA(Class-based FCFS) for the OLT suitable for embodying MPCP of the EPON. In this paper, we proposed methods that the EPON system can make use of by measuring end to end process delay time and the buffer size in order to implement the algorithm by using the OPNET.

內毒素가 大食細胞의 Neopterin 遊離에 미치는 影響

이순화,이충기,정태호 慶北大學校 醫科大學 1989 慶北醫大誌 Vol.30 No.4

The production of neopterin is closely correlated with activation of cellular immune reaction. Increased urinary neopterin levels has been observed in patients with malignant diseases, viral infections, autoimmune diseases, acquired immunodeficiency syndrome (AIDS), and allograft rejections. The in creased neopterin concentraions appear to be produced by human macrophages specifically stimulated with interferon-gamma. The purpose of this study was to investigate whether a potent macrophage stimulator such as lipopolysaccharide (LPS) can also induce neopterin release. Macrophages were cultivated with various concentrations of LPS for 72 h. As little as 1 ng/㎖ of LPS induced significant neopterin release. Elevated levels of neopterin were also detected in urine of patients with various infectious diseases. Extraordinarily high levels of neopterin were seen in septic shock patients. Levels of serum neopterin in patients with septic complications were significantly elevated as compared with controls. In addition, patients with fatal outcome always showed a higher neopterin levels than survivors.

고도정수처리공정에서 변이원성 활성도에 관한 연구

이순화,이철희,박영규,김재경,김차영 대한환경공학회 1999 대한환경공학회 학술발표논문집 Vol.1999 No.4

호소수 및 저니 간극수에서의 용존유기물질의 변화에 관한 연구

이순화,김용환 대한환경공학회 1998 대한환경공학회 학술발표논문집 Vol.1998 No.12

TETRA TRS에서 DMO 단말기의 전파도달범위 예측

이순화,김장복 한국인터넷방송통신학회 2014 한국인터넷방송통신학회 논문지 Vol.14 No.3

TETRA(TErrestrial Trunked RAdio)는 디지털 TRS(Trunked Radio System)의 유럽 표준으로 재난통신에 특화된 서비스를 제공한다. 특히 TETRA에서 제공하는 DMO(Direct Mode Operation) 기능은 기지국 중계 없이 단말 기간 직접통신이 가능하여 기지국 전파가 도달되지 않는 음영지역에 효과적으로 활용된다. 하지만 사용자들이 DMO 기능을 보다 효과적으로 활용하기 위해서는 전파도달범위 예측 정보가 제공되어야 한다. 따라서 본 논문에서는 국내에 보급되어 운용 중인 TETRA DMO 단말기의 링크버짓을 계산하고 이를 경로손실 모델에 적용시켜 지역 환경별 전파 도달 거리를 예측하였다. TETRA(TErrestrial Trunked RAdio) provide specialized disaster radio communication services as a standard European for digital TRS(Trunked Radio System). Especially, DMO(Direct Mode Operation) feature is used effectively in the radio shadow areas which base station does not propagate radio signal because it can communicate directly with terminal to terminal without base station's relay function. However, to effectively used DMO feature, radio coverage prediction information should be provided to users. Therefore in this paper, we were calculated link budget of TETRA DMO terminals which were distributing and operating in the country and then predicted reaching distance about radio propagation to be applied with path loss model.

30-40대 남성들의 패션 라이프스타일 요인이 외모관리행동에 미치는 영향-자기감시성에 따른 차이를 중심으로-

이순화,임은혁,전호경 한국인체미용예술학회 2016 한국인체미용예술학회지 Vol.17 No.1

The purpose of this study was to analyze the effects of fashion life style factors on appearance management behavior and to show how self-monitoring influences appearance management behaviors. Subjects for the study were men aged in their thirties and forties living in Seoul and Gyeonggi province. For the purpose of the study, the survey was conducted using convenience samples. A total number of 370 questionnaires were used for data analysis. For statistical analysis, factor analysis and multiple regression analysis were performed. The results of this study indicated that a fashion lifestyle was composed of four factors-fashion/appearance-oriented factor, ostentation-oriented factor, rational consumption- oriented factor, and dignity-oriented factor. The dependent variable of the study was appearance management behavior. Appearance management behavior consisted of interest in skin care and interest in fashion. A statistical analysis of multiple regression revealed that a fashion life style significantly influenced interest in skin care and interest in fashion. When subjects were categorized into two groups by self-monitoring, both respondents with high and low self-monitoring showed that fashion/appearance oriented factors significantly influenced interest in skin care. Fashion/appearance oriented factor influenced interest in skin care more for the subjects with high self-monitoring than for those with low self-monitoring. In contrast, fashion/appearance oriented factors had greater influence on interest in fashion for those subjects with low self-monitoring than those with high self-monitoring.

SDR기반 공용기지국환경의 'Wibro·WLAN·3G' 연동망 핸드오프 기법

이순화,김정섭,이승호,김장복 한국콘텐츠학회 2007 한국콘텐츠학회논문지 Vol.7 No.1

현재 무선 인터넷을 위한 패킷 데이터 서비스가 "WiBroWLAN3G"를 통해 제공되고 있으나 개별망에서는 Seamless한 환경을 만족시키기 어렵다. 그리고 WiBro와 WLAN은 서비스영역이 상대적으로 작아 광역서비스 제공시 기지국수가 늘어나게 된다. 따라서 이용자는 이동시 연속적이고 끊김없는 데이터서비스를 이용할 수 있으며, 사업자는 망 구축비용 및 운용비용 절감을 얻기 위해 통합연동망을 도입할 필요성이 있다. 따라서 본 논문에서는 SDR 공용기지국환경에서 “사용자요구대역폭”과 “단말이동속도”, “단말서비스셀지역”을 고려한 새로운 핸드오프 알고리즘을 제안하고 대역할당, QoS 만족도, 핸드오프 실패율의 우수성을 확인하였다. Today, packet services for wireless internet is provided by WiBroWLAN3G, but it is hard to be satisfied seamless connection in each of networks and wide-area service will increase the number of BS(base station) because WiBro and WLAN has been coverage smaller than 3G. that is, communicate which can use continuous and seamless data service is available when user is moving. Therefore, service provider need to integrate network for reducing management expenses. In this paper, we propose advanced handoff algorithm which is considered by "user demand bandwidth", "MN(Mobile Node) movement speed" and "MN service area" and show that simulating result is superior to "bandwidth allocation","QoS(Quality of Service) rate" and "handoff failure rate"