• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 Asia Navigation Conference
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• pp.79-84
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• 2006

A novel design of compact low-pass filter based on microstrip structure and its equivalent-circuit model are developed. The philosophy of the structure behind this novel microstrip low-pass filter is simple as it is composed of a pair of symmetrical parallel coupled-line and an open-stub. With this configuration, a finite attenuation pole near the stopband cutoff frequency is available and adjustable by simply tuning the circuit parameters. Furthermore, the rejection bandwidth of this type of low-pass filter can be extended. In order to validate the feasibility of the proposed design method, a low-pass filter based on a microstrip structure is designed, fabricated, and measured. Experimental results agree very well with the simulation and analytical results.

• 한국항만학회지
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• 제8권1호
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• pp.31-40
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• 1994

Experimental study is carried out to verify the advantages of an air chamber structure in controlling the wave transformation and its dynamic responses. The open, cross and vertical mooring systems are employed in experiments to investigate the variations of wave transmission ratio, natural period of the structures and tensile force acting on the mooring line according to the change of the initial air depth inside the air chamber structure. Experimental results show that the air chamber floating structure expresses the smaller wave transmission ratio and tensile force acting on the mooring line than general one without air chamber, expecially in the long period region of incident wave. Therefore, it is concluded that the air chamber structure suggested in this study can play good roles as a wave controlling castal structure, and a substitute structure of a general floating structure.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2023년도 춘계학술대회
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• pp.301-302
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• 2023

스마트 항로표지의 서비스를 동일한 규격으로 제공하고 사용자 인증과 접근 권한을 관리하기 위해 서비스 플랫폼을 설계하였다. 서비스 플랫폼의 요구사항을 충족하기 위해 사용자 인증을 위한 OIDC 구현 오픈소스인 Keycloak을 사용하였으며 서비스 관리를 위해서는 S-100 객체 카탈로그 버전 관리 방안을 사용하였다. 내부 서비스 데이터를 S-100으로 규격화 하기 위해서는 내부 서비스 데이터는 JSON Schema를 사용하여 S-100 데이터로 매핑을 위한 최소 규격을 설계하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2005년도 춘계학술대회 논문집
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• pp.285-290
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• 2005

지금까지 우리나라의 양식 산업은 양적인 측면에서 괄목할 만한 성장을 하였으나, 양적인 성장의 이면에 많은 문제를 파생시켜 최근에는 여러 가지 형태로 그 부작용이 나타나고 있다. 특히, 우리나라 양식 시설의 약 82%가 남해안의 내만에 집중 시설되어 있어 생활오수와 공장폐수의 유입 및 한정된 영역에서 장기간의 고밀도 양식으로 양식장들의 자가 오염등으로 어장환경이 악화되고 있다. 이같은 문제를 해소하기 위한 방안으로는 수질이 양호하며 해수유동이 많아 환경 피해가 적은 외해를 이용하는 것이 점차 대두되고 있다. 그러나 외해는 수질히 비교적 양호하나, 양식시설에 직접 피해를 줄 수 있는 높은 파도와 강한 흐름이 존재하고 있어 기존 내해용 양식시설로 외해로 진출하는 것이 곤란하므로 외해의 해양조건에 알맞은 양식 시설물의 개발이 필요하다. 본 연구는 이러한 필요성을 염두에 두고 외해양식에서 사용가능한 양식구조물의 설계에 필요한 이론적 연구와 실험적 해석을 수행하였다.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2000년도 종합학술발표회 논문집 Vol.10 No.1
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• pp.238-242
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• 2000

In this paper, the method for dielectric constant and less tangent measurements of microwave substrates using a microstrip line is presented. The two samples of an open-ended line and a short-ended tine are made and complex propagation constant is evaluated from the one-port scattering parameter measurements. This method has been automated fully using a personal computer and a vector network analyzer.

• 건축역사연구
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• 제15권3호
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• pp.81-98
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• 2006

Choryang Waekwan was the biggest Japanese settlment to house the Japanese diplomatic mission and traders in Korea. Waekwan means Japanese Pavilion literally, but the reality of this Waekwan exceeded much the scale of single architecture. Since Choryang Waekwan was closed in the second half of the nineteenth century, the site of this settlement grew rapidly as the downtown of Busan, which was the first port open to foreign countries in modern Korea. The formation of modern port owes much to the presence of Japanese settlment in Lee Dynasty as long as Choryang was officially designated as the trading port toward Japan and vice versa. Busan is the nearest city to Japan, in fact. Within a day ships could reach Tsushima Island, the island region north of Fukuoka, which played an intermediary role between Seoul and Edo. No architectural remain could be seen on the actual site of Choryang Waekwan. The site has become one of the busiest centers in Busan with quantify of office buildings and shops. The former Busan City Hall was located in this area. The field survey of the site as well as the analysis of historical documents, which were newly found both in Korea and in Japan, enabled to reconstruct the architecture and cityscape of Waekwan by way of computer graphics.

• Nuclear Engineering and Technology
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• 제53권6호
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• pp.1810-1820
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• 2021

Study of single bubble behavior under rolling motions can prove useful for fundamental understanding of flow field inside the modern small modular nuclear reactors. The objective of the present study is to simulate the influence of rolling conditions on single rising bubble in a liquid using multiphase Moving Particle Semi-implicit (MPS) method. Rolling force term was added to 2D Navier-Stokes equations and a computer program was written using C language employing OpenACC to port the code to GPU. Computational results obtained were found to be in good agreement with the results available in literature. The impact of rolling parameters on trajectory and velocity of the rising bubble has been studied. It has been found that bubble rise velocity increases with rolling amplitude due to modification of flow field around the bubble. It has also been concluded that the oscillations of free surface, caused by rolling, influence the bubble trajectory. Furthermore, it has been discovered that smaller vessel width reduces the impact of rolling motions on the rising bubble. The effect of liquid viscosity on bubble rising under rolling was also investigated and it was found that effects of rolling became more pronounced with the increase of liquid viscosity.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8221-8224
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• 2014

Gastric cancer continues to be a leading cause of cancer death. The majority of patients with gastric adenocarcinoma in China present with advanced disease. Ruling out unresectable cancers from an unnecessary "open" exploration is very important. The aim of this study was to assess the value of five-port anatomical laparoscopic exploration in T4 gastric cancer in comparison with three-port laparoscopic exploration and laparotomy exploration. We conducted a retrospective study on 126 patients with T4 stage scheduled for D2 curative gastrectomy based on computed tomography (CT) staging at Department of Gastric Cancer and Soft Tissue Sarcoma, Fudan University Shanghai Cancer Center, from Apr. 2011 to Apr. 2013. Laparotomy exploration (Group I), three-port laparoscopic exploration (Group II) or five-port anatomical laparoscopic exploration (Group III) were performed prior to radical gastrectomy. Accuracy rate for feasibility of D2 curative gastrectomy in laparotomy exploration and five-port anatomical laparoscopic exploration groups was higher than that in the three-port laparoscopic exploration group. Five-port anatomical laparoscopic exploration group had the highest accuracy resection rate (Group I vs Group II vs Group III,92.6% vs78.6% vs 97.7%; p<0.05) and shorter length of hospitalization (Group I vs Group II vs Group III, $9.58{\pm}4.17$ vs $6.13{\pm}2.85$ vs $5.00{\pm}1.81$; p<0.001). Three-port laparoscopic exploration has low accuracy rate for assessing feasibility of D2 curative gastrectomy and five-port anatomical laparoscopic exploration should be performed on patients with T4 gastric cancer.

• 한국경제지리학회지
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• 제14권3호
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• pp.407-418
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• 2011

광저우(廣州)를 성도(省都)로 하는 광둥성 주변 남쪽지방은 기원전 221년 진(秦)나라가 통일하기 전까지 지형적으로 교통의 장애를 초래한 오령(五嶺; 다섯 산맥)의 남쪽에 있다하여 '영남(嶺南)'이라 불렸다. 영남의 광둥성 일대는 행정적 독립단위의 남월국(南越國)이라 하였다. 이 지역을 대표하는 '월'이란 한자의 기원은 여기서 비롯되며 월어(광둥어), 월채(광둥요리), 월극(광둥 연극) 등 용어는 지금도 사용된다. 남월국 시대에 번우(番禹)라 불렸던 광저우는 주강(珠江) 삼각주 북부에 일찍이 자리를 잡았다. 이후 청대(淸代)에 이르러 서구 열강에 문호를 개방하게 된 최초의 개항장이 되었다. 오늘날에는 후발 주자인 상하이(上海)에 뒤쳐지기도 했으나 여전히 베이징, 상하이에 이은 세 번째 영향력을 지닌 연해 개방 도시이다. 광저우는 오늘날 세계적인 면방직 공업의 중심일 뿐 아니라 여러 업종의 공업 발달에 박차를 가하고 있는 도시이다. 주변의 홍콩, 마카오, 선전 등과 함께 주강 삼각 경제권 구축에 중요한 역할을 담당하고 있다. 일찍이 화남 최대의 중심도시로 자리 잡은 광저우는 이 지역 정치 경제 문화 등 다방면의 허브인 동시에 북방 정치권에 도전하려는 혁명저항 세력의 중심도시였다. 광저우는 항만으로서 성쇠의 역사를 거쳐 왔지만 지속적인 노력으로 발전하면서 영향력을 지니게 되었다. 그렇지만, 오늘날 역동적으로 발전하는 광저우의 모습 이면에 환경과 질서 등 개선되어야 할 여러 과제를 안고 있다.

• ETRI Journal
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• 제41권2호
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• pp.197-206
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• 2019

Software-defined networking (SDN) is a modern approach for current computer and data networks. The increase in the number of business websites has resulted in an exponential growth in web traffic. To cope with the increased demands, multiple web servers with a front-end load balancer are widely used by organizations and businesses as a viable solution to improve the performance. In this paper, we propose a load-balancing mechanism for SDN. Our approach allocates web requests to each server according to its response time and the traffic volume of the corresponding switch port. The centralized SDN controller periodically collects this information to maintain an up-to-date view of the load distribution among the servers, and incoming user requests are redirected to the most appropriate server. The simulation results confirm the superiority of our approach compared to several other techniques. Compared to LBBSRT, round robin, and random selection methods, our mechanism improves the average response time by 19.58%, 33.94%, and 57.41%, respectively. Furthermore, the average improvement of throughput in comparison with these algorithms is 16.52%, 29.72%, and 58.27%, respectively.