• Journal of the Earthquake Engineering Society of Korea
• /
• v.7 no.2
• /
• pp.85-92
• /
• 2003

This paper presents an electric power generating system for stand-alone health monitoring sensor unit of bridge structure based on ambient vibration of bridge. In this paper, a novel electric power generator which has minimum effect of armature reaction is proposed. The related mechanical and electrical design equations are obtained, and a pilot generator has been implemented. In addition, the charging system for extremely low generator current is discussed, and some improvements are identified for the system. This investigation reveals that diode characteristics of rectifier is dominant factor in the charging process. Finally, both the simulation, which uses real measurement data of the Namhae bridge as input of the pilot generator, and indoor test are carried out. The results showed the applicability and effectiveness of the stand-alone vibration powered generator.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.13 no.3 s.55
• /
• pp.135-144
• /
• 2009

The cable system of suspension bridges is a very important non-elastic element which caries an external load by a tension force of the cable, such that creates the integrity of a structure. It is not easy to find if cable system have been changed by the maintenance activities such as repairs or reinforcement. Sometimes the maintenance can cause structural deformations and changes of the tension force in cables. In most cases, the cable stayed bridges are managed by health monitering system, however, the main cable of suspension bridges need to develop more accurate and efficient monitoring system. The Namhee Bridge was constructed 35 years ago and it has been continually repaired and reinforced after then. This study describes the behavior of the cable system by analysing many of inspective reports and by using the results of hanger rope test and for the shape of main cables surveys.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2014.06a
• /
• pp.192-194
• /
• 2014

한일합방 직전인 1909년 12월에 초점등된 가덕도(구)등대는 가덕도의 끝단 동두말에 위치하고 있으며, 이위치는 부산 남해는 물론 거제도가 한눈에 들어오는 광범위한 시계를 가지고 있어 예로부터 군사적 지리적 요충지로 역할을 수행하고 있다. 또한 가덕도는 2010년 거가대교 개통으로 교통의 요충지가 되었다. 가덕도(구)등대는 역사적 보존가치가 높아 해양수산부에 의해 등대문화유산 제8호로 지정되었고, 가덕도(구)등대의 등탑과 결합된 등대 숙사의 문화재적 가치가 높아 부산시 유형문화재 제50호로 지정되었다. 등탑과 숙사가 일체화된 경우도 드물어 건축적 가치가 높을 뿐만 아니라, 숙사의 건축형태와 현관장식 등의 미관이 수려하다. 이렇게 지리적, 역사적, 건축사적 가치를 가지고 있는 가덕도(구)등대는 100주년을 맞이하여 100주년 기념관, 체험숙소 등을 운영하고 있다. 하지만 여러 가지 유해한 요인들 때문에 문화재적 가치가 빛을 발하지 못하고 있다. 이에 따라 본 연구는 가덕도(구)등대의 실태조사를 통하여 유해 요인 제거 및 이전 방안에 대한 계획을 수립하고 문화재적 가치 향상과 환경개선, 보존관리를 목적으로 한다.

• Ocean and Polar Research
• /
• v.34 no.2
• /
• pp.137-149
• /
• 2012

Hemocyte parameters of the wild Pacific oyster Crassostrea gigas inhabiting intertidal zones in small bays (Gwangyang and Jinhae Bay) on the southern coast of Korea were evaluated using flow cytometry and neutral red retention (NRR) assay. Morphological features, cell count, mortality, DNA damage, phagocytosis, and lysosomal membrane stability of hemocytes were analyzed. Three types of hemocytes were identified in the oyster hemolymph: granulocytes, hyalinocytes, and blast-like cells. Immune related functions of hemocyte including phagocytosis and lysosomal membrane stability were significantly different among the study areas (P<0.05), while cell count, mortality, and DNA damage of hemocytes were not significantly different. In Gwangyang Bay, phagocytosis of granulocytes and lysosomal membrane stability of oyster hemocytes inhabiting inside bay were significantly lower than those of oyster hemocytes in outside bay (P<0.05), indicating that oysters in inside bay of Gwangyang were relatively suppressed the immunological function in hemocytes. Contrary to Gwangyang Bay, immune parameters of oyster hemocytes in Jinhae Bay not showed the difference between sampling sites. In conclusion, flow cytometry and NRR assay using oyster hemocyte has a powerful tool to investigate the cell level in a short time due to no-preprocessing of material.