차세대이동통신(IMT-2000/FPLMTS) 개발 및 표준화

류승완,최창식,Ryu, Seung-Wan,Choe, Chang-Sik 한국전자통신연구원 1997 전자통신동향분석 Vol.12 No.4

차세대이동통신(IMT-2000/FPLMTS)을 중심으로 한 이동통신은 고도 정보화사회를 열어가는 주역으로 2000년대 초에는 전체 통신서비스의 약 50% 정도를 점유할 것으로 예견되고 있다. 본 고에서는 차세대 이동통신인 IMT-2000/FPLMTS에 대한 국제 표준화 동향 및 미국, 유럽, 일본 등의 표준화 및 개발 동향을 살펴보기로 하겠다. 또한 우리나라의 표준화 및 개발 동향을 살펴봄으로써 CDMA 디지털 셀룰러 세계 최초 상용화로 이룩한 이동통신 선진국의 위치를 차세대 이동통신 분야에서도 실현하여 우리나라가 이동통신 대국이 되는 방안을 모색해보기로 하겠다.

이동통신과 국가경쟁력

류승완,Ryu, Seung-Wan 한국전자통신연구원 1996 전자통신동향분석 Vol.11 No.3

현대 사회는 디지털 이동통신, 개인휴대통신, 초고속정보통신서비스의 제공으로 고도 정보화 사회로 급속히 이행되고 있으며, 특히 이동통신은 통신의 개인화 성향으로 인해 21세기 정보통신의 주역으로 급부상하고 있다. 이러한 시점에서 세계 각국과 우리나라의 이동통신 서비스와 산업의 현황과 경쟁력을 살펴보고 비교해봄으로써, 21세기 통신대국으로 부상하기 위한 우리나라 이동통신산업의 당면과제를 도출하고 나아갈 바를 제시하였다.

Time Utility and Channel State based Wireless Downlink Packet Scheduling Algorithm for OFDMA System

류승완,서현화,정수정,임순용,박세권,Ryu, Seung-Wan,Seo, Hyun-Hwa,Chung, Soo-Jung,Lim, Soon-Yong,Park, Sei-Kwon 대한산업공학회 2004 산업공학 Vol.17 No.S

In this paper, we propose an urgency and efficiency based wireless packet scheduling (UEPS) algorithm that is able to schedule real time (RT) and non-real time (NRT) traffics at the same time. The proposed UEPS algorithm is designed to support wireless downlink packet scheduling in the OFDMA system which is a strong candidate wireless system for the next generation mobile communications. The UEPS algorithm uses the time-utility function as a scheduling urgency factor and the relative status of the current channel to the average one as an efficiency indicator of radio resource usage. The design goal of the UEPS algorithm is to maximize throughput of NRT traffics with satisfying QoS requirements of RT traffics. The simulation study shows that the proposed UEPS algorithm is able to give better throughput performance than existing wireless packet scheduling algorithms such as proportional fair (PF) and modified-largest weighted delay first (M-LWDF) while satisfying QoS requirements of RT traffics such as the average delay and the packet loss rate under various traffic loads.

용접형강의 직접강도법 개발에 관한 연구 고찰

류승완,박성웅,권영봉,Ryu, Seung Wan,Park, Sung Woong,Kwon, Young Bong 한국강구조학회 2015 韓國鋼構造學會 論文集 Vol.27 No.2

직접강도법은 NAS(2004)와 AS/NZS 4600(2005)에 의해서 냉간성형강재의 설계에 처음 채택되었다. 이 설계법은 용접형강 부재에도 효과적으로 적용이 가능하다고 판단된다. 본 논문에서는 최근 수행된 용접형강 부재의 직접강도법 개발에 대해서 살펴보고자 한다. 용접형강 압축 및 휨부재의 설계강도식은 H, C, RHS, CHS 형강, 플레이트거더 및 보강판 단면의 실험 결과에 근거하여 개발 되었다. 직접강도법과 현행 설계기준에 의해 예측된 강도의 비교 결과를 통하여 직접강도법을 적용하여 좌굴혼합이 발생하는 용접형강 기둥 및 보 부재의 압축, 휨 및 전단강도를 합리적으로 산정할 수 있는 것을 입증하였다. The direct strength method (DSM) has been adopted by the NAS (2004) and AS/NZS 4600 (2005) for the design of cold-formed steel members. The method can be successfully applied to the design of welded steel members. This paper reviews the development of the DSM for welded steel structural members. The design strength formulae for welded section columns and beams for the DSM are based on the test results performed on welded H-section, C-section, circular and rectangular hollow section columns, plate girders and stiffened plates. The comparison between the design strength of welded sections predicted by the DSM and that estimated by existing specifications is also provided. The comparison verifies that the DSM can properly predict the compressive, flexural and shear strength of welded section columns and beams with the interaction between local and overall buckling.

위에서 발생한 원발성 융모암

류승완(Seung Wan Ryu),손수상(Soo Sang Sohn),김인호(In Ho Kim) 대한외과학회 2003 Annals of Surgical Treatment and Research Vol.65 No.4

공연장서비스의 고객만족도 향상을 위한 서비스 요인의 상대적 중요도와 우선순위 도출 - 대형 뮤지컬 공연장을 중심으로 -

류승완 ( Seung Wan Ryu ),강하나 ( Ha Na Kang ),이유나 ( You Na Lee ) 한국경영공학회 2015 한국경영공학회지 Vol.20 No.1

In this study, in contrast to the conventional artistic perspective oriented research on performing arts, the musical performance delivery mechanism at a large theater is defined and analyzed as a theater service due to its inherent resemblance to services. In order to analyze the theater service, the service blueprint method is applied to identify service provision process to audiences. The theater service process is consisting of many supporting service functionalities including the on-stage and the back-stage supporting functions. Therefore, the theater service is also identified as a combined process of many supporting service functions. In addition, potential service failure points and waiting points that may deteriorate theater service quality are identified. Examples of potential failure points are the customer complain handling, confirmation of pre-purchased tickets, on-site ticketing and the theater map guidance. Relative importance and the order of priority of such potential service failure points are important not only for preventing service failure occurrence, but also for improving customer satisfaction. In this study, the Analytic Hierarchy Process (AHP) is applied to investigate the relative importance of several potential failure points. Then, effective service recovery strategies and service improvement methods are proposed. Analysis results of this study can also be useful for future performing arts related research works. For example, many supporting functions of the theater service and their relation identified in this study can be used for establishment of a standardized performing arts service provision process. These results can also be used for the mid and small size performing arts provision service process so as to improve customer satisfaction and performance profitability of such services.

외상 후 생긴 소장 협착

류승완(Seung Wan Ryu),김인호(In Ho Kim),권중혁(Jung Hyeok Kwon),손수상(Soo Sang Sohn) 대한외과학회 2003 Annals of Surgical Treatment and Research Vol.65 No.5

근감소증과 악액질의 임상적 특성

류승완 ( Seung-wan Ryu ) 한국정맥경장영양학회 2017 한국정맥경장영양학회지 Vol.9 No.1

Sarcopenia, which is defined as a decrease in skeletal muscle mass and strength with aging, is an important risk factor in clinical medicine that is associated with mortality, and poor surgical and nonsurgical outcomes. Sarcopenia is now recognized as a multifactorial geriatric syndrome. Cachexia is defined as a metabolic syndrome with inflammation as the key feature, so cachexia can be an underlying condition of sarcopenia. Recently, cachexia has been defined as a complex metabolic syndrome associated with an underlying illness and characterized by the loss of muscle mass with or without a loss of fat mass. These two conditions overlap but are not the same. In clinical practice, many factors related to sarcopenia (decreased food intake, inactivity, and decreased hormones) are reported frequently in patients with cachexia. On the contrary, systemic inflammation, the core feature of cachexia, can also be present in apparently healthy older sarcopenic patients. This suggests that new therapeutic approaches, alone or in combination, may be appropriate in both conditions.

악성 종양을 지닌 환자의 복수에서의 염색체 분석

류승완(Seung-Wan Ryu),정기용(Ki-Yong Chung),김대광(Dae-Kwang Kim) 대한해부학회 1999 Anatomy & Cell Biology Vol.32 No.5

암환자에서 생기는 복수는 환자의 예후와 밀접한 관계가 있으므로 원인 질환의 감별이 매우 중요하다. 통상적으로 세포 학적 검사에서 높은 확률로 암세포를 복수에서 검출할 수 있으나 매우 숙련된 판독력이 필요로 하며 위음성이 높게 나타날 수 있다. 국내에서는 아직까지 암환자의 복수에서 염색체 표본을 제작하여 암세포의 존재를 조사한 보고는 아직 없다. 본 연구에서는 9명의 암환자에서 발생한 복수를 직접법과 단기간 배양을 한 후 염색체를 분석하는 방법으로 암세포를 검출하는 실험을 하였으며, 그 결과를 세포학적 진단 결과와 서로 비교해 보았다. 세포학적 진단 결과를 얻을 수 있었던 5례에서는 암세포가 검출되지 않았으나, 이들의 복수에서 염색체 검사를 실시한 결과는 1례에서 암세포가 검출되었고 암세포가 존재하리라고 의심되는 경우가 1례로 나타났다. 그리고 세포학적 진단 결과를 얻을 수 없었던 4례에서는 세포유전학 분석 방법으로 3례의 복수에서 암세포를 검출할 수 있었다. 향후 많은 복수를 실험 대상으로 암세포를 검출하는데 세포유전학 검사를 실시하면 이미 가슴막액에서 실시한 서구의 결 과와 유사하게 세포학적 진단보다도 세포유전학 검사가 높은 감수성과 특이성을 보일 것으로 추정된다. 그리고 복수에서 암세포가 존재할 가능성이 높은 경우에는 세포학적 진단과 염색체 검사를 실시하면 세포유전학 방법이 종양세포의 양성 검출율을 높여 세포학 진단 결과를 보강해주는 역할을 할 것이며 그리고 복막생검과 같은 침입성 진단 방법을 사용할 필요성이 감소할 것이다. Detecting malignant cells in ascitic f luid from tumor patients is important since the existence of malignant cells in ascitic f luids is related to the prognosis of patients. Various laboratory methods are being used to obtain diagnosis in ascitic f luids, but some ascitic f luids can not be diagnosed reliably. Cytogenetic analysis of ascitic f luid is not used routinely as a laboratory tool. In this presentation a cytogenetic study of the ascitic f luids from 9 patients with malignant tumor was performed by a direct or short-term culture method. According to cytogenetic study, 5 cases had positive f indings for malignant cells. One case had a inconclusive result. There were no malignant cells in the remaining 4 cases. On blind cytologic data, no informations could be obtained in 4 out of 9 cases and the remaining 5 cases had negative findings for detecting malignant cells. Among the 5 cases, cytogenetic findings were negative in 3 cases but in the remaining 2 cases, one was reported positive and the other inconclusive each other. In present study, even though the ascitic f luids from 5 patients were subjected to the comparison of the cytologic study with cytogenetic analysis, two different f indings could be obtained. Therefore if further study of a large series of cancer patients with ascitic fluids is done, the value of cytogenetic analysis will be clearly shown. In addition, the cytogenetic study of cell present in ascitic f luids can be used as useful adjunct to cytologic study, and also it can indicate that more invasive diagnostic procedures are necessary.

위장관 간질종양에 관련된 유전자의 돌연변이

류승완(Seung Wan Ryu),정창욱(Chang Wook Jeong),황재연(Jae Youn Hwang),김인호(In Ho Kim),정효순(Hyo Soon Jeong),강유나(Yu Na Kang),손수상(Soo Sang Sohn),김대광(Dae Kwang Kim) 대한외과학회 2005 Annals of Surgical Treatment and Research(ASRT) Vol.68 No.2