Development of a Precise Orbit Determination System for GPS

Park Eun-Seo,Jung Sung-Wook,Park Sang-Young,Choi Kyu-Hong,Lee Woo-Kyoung,Cho Sungki,Park Jong-Uk,Park Pil-Ho 한국우주과학회 2005 한국우주과학회보 Vol.14 No.2

OWL-Net: A global network of robotic telescopes for satellite observation

Park, Jang-Hyun,Yim, Hong-Suh,Choi, Young-Jun,Jo, Jung Hyun,Moon, Hong-Kyu,Park, Young-Sik,Bae, Young-Ho,Park, Sun-Youp,Roh, Dong-Goo,Cho, Sungki,Choi, Eun-Jung,Kim, Myung-Jin,Choi, Jin Elsevier 2018 ADVANCES IN SPACE RESEARCH Vol.62 No.1

<P><B>Abstract</B></P> <P>The OWL-Net (Optical Wide-field patroL Network) is composed of 0.5-m wide-field optical telescopes spread over the globe (Mongolia, Morocco, Israel, South Korea, and USA). All the observing stations are identical, operated in a fully robotic manner, and controlled by the headquarters located in Daejeon, Korea. The main objective of the OWL-Net is to obtain the orbital information of Korean LEO and GEO satellites using purely optical means and to maintain their orbital elements.</P> <P>The aperture size of the mirror is 0.5 m in the Ritchey-Chretien configuration, and its field of view is 1.1 deg on the CCD sensor. The telescope is equipped with an electrically cooled 4 K CCD camera with a 9-µm pixel size, and its pixel scale is 1 arcsec/pixel. A chopper wheel with variable speed is adopted to obtain multiple points in a single shot. Each observatory is equipped with a heavy-duty environment monitoring system for robust robotic observation. The headquarters has components for status monitoring, scheduling, network operation, orbit calculation, and database management.</P> <P>The test-phase operation of the whole system began in early 2017, although test runs for individual sites began in 2015. Although the OWL-Net has 7 observation modes for artificial satellites and astronomical objects, we are concentrating on a few modes for LEO satellites and calibration during the early phase. Some early results and analysis for system performance will be presented, and their implications will be discussed.</P>

Study on the Changes in Enzyme and Insulin-like Growth Factor-1 Concentrations in Blood Serum and Growth Characteristics of Velvet Antler during the Antler Growth Period in Sika Deer (Cervus nippon)

Park, Jaehyun,Jeon, Byongtae,Kang, Sungki,Oh, Mirae,Kim, Myonghwa,Jang, Seyoung,Park, Pyojam,Kim, Sangwoo,Moon, Sangho Asian Australasian Association of Animal Productio 2015 Animal Bioscience Vol.28 No.9

This study was conducted to investigate changes in blood enzyme parameters and to evaluate the relationship between insulin-like growth factor-1 (IGF-1), antler growth and body weight during the antler growth of sika deer (Cervus nippon). Serum enzyme activity and IGF-1 concentrations were measured in blood samples collected from the jugular and femoral veins at regular intervals during the antler growth period. Blood samples were taken in the morning from fasted stags (n = 12) which were healthy and showed no clinical signs of disease. Alfalfa was available ad libitum and concentrates were given at 1% of body weight to all stags. The experimental diet was provided at 9 am with water available at all times. There were no significant differences in alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase during antler growth, but alkaline phosphatase concentrations increased with antler growth progression, and the highest alkaline phosphatase concentration was obtained 55 days after antler casting. Serum IGF-1 concentrations measured from blood samples taken from the jugular vein during antler growth, determined that levels of IGF-1 was associated with body weight and antler growth patterns. Serum IGF-1 concentrations were higher at the antler cutting date than other sampling dates. Antler length increased significantly during antler growth (p<0.001), and there was a similar trend to between right and left beams. Body weight increased with antler growth but was not significant. Consequently it appeared that serum alkaline phosphatase concentration was related to antler growth and both antler growth and body weight were associated positively with IGF-1 concentrations during antler growth.

Pairwise Skorokhod Convergent Topology

Park, Sungki 조선대학교 기초과학연구소 1979 自然科學硏究 Vol.2 No.1

제3궤조 집전방식 도시철도의 건축한계 적용에 대한 연구

박성기(Sungki Park),구정서(Jeongseo Koo),함영삼(Yeongsam Ham) 한국철도학회 2016 한국철도학회 학술발표대회논문집 Vol.2016 No.5

최근 국내 지방자치단체에서 신규 설치하는 도시철도는 총사업비 절감을 위해 제3궤조 집전방식의 무인 경전철 차량운행시스템을 다수 운영 하고 있다. 신규노선의 총사업비 절감을 위해서는 공사비 비중이 큰 토목공사의 비용절감이 절대적으로 필요하며, 이를 위해 각 지자체는 차량의 안전 주행을 확보하면서 터널 Size최소를 위해 터널 구축한계에 대한 관련 법령과 규정을 적용하여 터널 Size를 선정하고 있다. 이에 본 연구는 현재 설치되고 있는 제3궤조 집전방식 도시철도의 건축한계 적용사례(인천2호선)를 중심으로 차량의 횡변위를 분석하고, 횡변위 분석결과와 관련 법령에 의거 설치된 건축한계와의 저촉여부를 검증하여, 제3궤조방식 도시철도 차량의 최적 건축한계 적용 방향을 제시하고자 한다 Recent years the local governments in Korea have been tending to construct the 3rd Rail System together with an unmanned Light Railway Transit in order to reduce the budget. Reduction of the construction budget makes us focus on the tunnel size as the Civil Works that shares major portion of the budget. For this the local governments try to minimize the tunnel size while considering the safe operation of the train, the Construction Gauge, and the related laws and regulations. In this study, we analyze the Lateral Movements of the Rolling Stock, compare the Construction Gauge determined by the laws and regulations with the analysis result, and validate the infringements on the Construction Gauge of the Incheon Line 2 as a reference project. Then we bring an optimal application of the Construction Gauge of an Urban Railway Transit with the 3rd Rail System in order to facilitate the local governments’ efforts.

차륜 독립구동형 직렬 하이브리드 지게차의 연비 분석을 위한 후륜 조향시스템 모델링

박태호(Taeho Park),이성화(Sunghwa Lee),김지훈(Jihoon Kim),김성기(Sungki Kim),박기형(Gihyoung Park),이형철(Hyeongcheol Lee) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5

This paper introduces the modeling of the hybrid forklift, which simulates the effect of the rear-wheel steering system. Most of working cycles of the forklift consist of frequent tight turnings, as well as many starts and stops. Moreover, the maximum of the rear-wheel steering angle is about two or three times larger than that of the front-wheel steering angle in the passenger car. Therefore, the speed difference between the inner-wheel and the outer-wheel cannot be ignored in the cycle simulation, differently from most researches about the hybrid passenger car. In this paper, the speed of each wheel is calculated using the Ackermann geometry, where the wheel steering angles are calculated by kinematic model of the steering mechanism. This steering system model is combined with a powertrain model for the series hybrid forklift. All of these models are developed in the Simulink® environment. The simulation result shows that the operating point of the each traction motor is differed from each other when turning at the tight corner.

내부 온습도 측정을 통한 초기재령의 콘크리트 내부 습도 및 수화열 변화 특성 분석

홍성기(Hong, Sungki),박철우(Park, Cheolwoo),박성재(Park, Sungjae),강태성(Kang, Taesung),김희성(Kim, Heesung) 한국콘크리트학회 2008 한국콘크리트학회 학술대회 논문집 Vol.2008 No.11

Establishment of an Evaluation System for Port Infrastructure Competitiveness: Support Sustainable Marine Transportation

박주동(Ju-Dong Park),이종필(Jong-Phil Lee),이기열(Ki-Youl Lee),김성기(Sungki Kim),김성아(Sung-Ah Kim),이주원(Joo-Won Lee),박상원(Sang-Won Park),김형태(Hyung-Tae Kim) 중앙대학교 한국전자무역연구소 2020 전자무역연구 Vol.18 No.2

연구목적: 본 연구는 우리나라 항만시설 경쟁력을 평가하여 실태를 파악하고 개선방안을 도출하기 위한 목적으로 수행 되었다. 현재 전 세계 다양한 해운항만물류 관련 평가체계는 정량적 또는 정성적 중심으로 이루어져 종합적인 평가는 어려운 실정이다. 또한, 우리나라 해운항만물류분야에 대한 평가는 다소 절하되어 있다. 이에 본 연구에서는 정량적 및 정성적 요인을 동시에 고려한 종합적이고, 최근의 글로벌 해운항만물류 트렌드를 반영한 평가체계를 개발하였다. 논문구성/논리: 본 연구는 총 5개의 장으로 구성되어 있다. 2장은 항만 관련 선행연구와 해운항만물류 관련 지수의 국내외 사례연구 분석을 통해 시사점을 도출하려한다. 3장에서는 평가체계 개발 과정 및 평가 방법을 소개한다. 4장은 우리나라 항만을 대상을 수행한 시범사업의 평가 결과를 제시한다. 결과: 30개 무역항을 대상으로 평가해본 결과, 우리나라 항만은 전반적으로 안전하고 디지털 관련 시설이 잘 확보되어 있는 반면 정시성 확보를 위한 시설 개선 및 운영 효율성 제고가 필요한 것으로 나타났다. 특히, 친환경 시설에 대한 대대적인 투자와 개발은 매우 시급한 것으로 판단되었다. 독창성/가치: 현재까지 전 세계적으로 항만시설의 경쟁력 수준을 정시성, 안전, 친환경, 디지털 등 다양한 부문에 대한 정량적·정성적 요인들을 동시에 반영하는 포괄적인 평가체계는 전무하다. 본 연구에서는 이 같은 포괄적인 평가가 가능한 지수를 개발한데 큰 의미가 있고, 시범평가를 통해 우리나라 항만의 주요취급 화물별 시설 경쟁력 수준을 파악하였다. 이는 향후 우리나라 항만시설 경쟁력 제고를 위한 투자 및 개발의 우선순위 산정의 기초자료로 활용이 가능할 것이다. 또한, 장기적인 관점에서는 지속적인 수정/보완을 거쳐 국제지수로 확대 가능할 것으로 판단된다. Purpose: This study was conducted to understand the current status and derive improvement points by evaluating the competitiveness of Korean port infrastructure. At present, various shipping-port-logistics related evaluation systems around the world are either quantitative or qualitative rather than comprehensive evaluation. However, the result of evaluation for the shipping-port-logistics sector in Korea on a global level is undervalued and this is different from the real situation. Composition/Logic: This study consists of five chapters. Chapter 2 attempts to derive implications through a literature review on ports and analysis of domestic and foreign case studies of shipping port logistics-related indices. Chapter 3 introduces the development process of the evaluation system(index) and evaluation method. Chapter 4 presents the evaluation results of the pilot project that conducted the port in Korea. Findings: As a result of evaluating the 30 trade ports in Korea, it was found that Korea s ports are generally safe and digitally secured, while improving facilities and improving operational efficiency are needed to secure on schedule time. In particular, it should be considered that it is urgent to make a large investment toward developing eco-friendly facilities. Originality/Value: In this study, it was meaningful to develop an index capable of such comprehensive evaluation, and through the pilot project, the competitiveness level of facilities in each port of Korea was identified. This study could be used as the initial resource for the prioritization of investment and development to enhance the competitiveness of Korean trade ports in the future. Furthermore, in the long term, it would be expanded to the international index through continuous revision and supplementation.

寫像擴張에 關한 硏究

朴性璂 조선대학교 기초과학연구소 1978 自然科學硏究 Vol.1 No.1

Effects of Revenue-Sharing Contracts on the Profits of Competing Manufacturers and a Retailer

Sungki Kim(김성기),Nina Shin(신니나),Sangwook Park(박상욱) 한국경영과학회 2018 한국경영과학회지 Vol.43 No.2

This study investigates the effect of revenue-sharing contracts in two competing manufacturers and one common retailer model under game theoretic settings. One manufacturer uses a revenue-sharing contract (RSC) and the competitor a wholesale price contract (WPC). We study whether the adoption of an RSC coordinates the supply chain of the RSC-adopting manufacturer and the retailer and how it affects two manufacturers’ profits under two game scenarios : two-stage and one-stage game. We analyze the effects of demand parameters which represent product characteristic, such as price sensitivity and product substitutability on supply chain members’ profits. We find that the RSC in the two-stage game does not coordinate the supply chain. Conversely, the RSC in the one-stage game coordinates the corresponding supply chain for some sets of demand parameters values, and that for others, the competing manufacturer experience greater profit increase than the RSC-adopting one.