• ALGAE
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• v.30 no.2
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• pp.103-119
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• 2015

Photosynthetic rates of the large centric diatom Coscinodiscus granii were measured by means of multicolor variable chlorophyll fluorescence imaging, single cell $^{14}C$ assimilation, and optical $O_2$ sensor measurements during light acclimatization of cultures grown at five different irradiances: 50, 150, 235, 332, and $450{\mu}mol$ photons $m^{-2}\;s^{-1}$. Photo-acclimatization was evident from changes of cellular chlorophyll a content, growth rates, and light response curves. Each of the applied methods evaluates different parts and reactions in the photosynthetic apparatus, which makes a direct quantitative comparison of rates difficult, although a different degree of correlation were found between all three methods. However, when used in combination, they provide information about the internal relationship of photosynthetic pathways as well as the variation in photosynthetic capacity between individual cells within a single algal culture.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.3
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• pp.265-268
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• 2011

In this paper, we designed and fabricated that fog alarm equipment detected to crew in maritime fog. Developed fog alarm equipment was combined sensor and a transmitter-receiver module using emitting device unit and receiver photoelectric element infrared LED using only the receive sensitivity was low, miniaturization. Experiment of the fabricated device had a standard that was humidity 70%, the fabricated one generating artificial-fog within visibility 1km. When humidity is over 70%, the fabricated one generates alarming sounds for a warning. When developed device apply to vessel will be able to respond quickly, according to dense fog in the accident.

• Tribology and Lubricants
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• v.30 no.6
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• pp.356-363
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• 2014

Marine diesel engines operate in environments in which damage easily occurs from corrosion. Recently, damage to cylinder liners has increased from corrosion wear caused by increased engine power. This damage can cause serious problems in the economy. Thus, many researchers have treated and studied damaged cylinder liners. However, a method is necessary for real-time monitoring of damage to cylinder liners during operation of the engine, before serious damage can occur. This study carries out reciprocating friction and wear tests on a cast iron specimen under various corrosion atmospheres and verifies the variations of friction coefficient and friction surface. Additionally, the friction coefficient and friction status are predicted by using a neural network that learns the vibration and frequency spectrum data from an acceleration sensor. According to our conclusions, amplitude is distributed highly at high frequencies, and values of standard deviation and kurtosis are high when damage to the friction surface is serious. The accuracy rate of the friction coefficient predicted by the neural network is over 80% of the real measured value without NaCl, and application of the neural network is very effective for diagnosing the friction condition and damage to the cylinder liner.

• Journal of Navigation and Port Research
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• v.32 no.2
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• pp.121-126
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• 2008

This paper presents hull stress monitoring system installed in LNGC damaged by a Typhoon Elongation/contraction of removed areas has been assessed in terms of possible residual stress that will take place in replaced blocks when the applied load is removed. The bending moment of a vessel changes actually in terms of loss of longitudinal members and the change of weight distribution in repair procedure. The change of bending moment affects mainly in hull stress of longitudinal members. Hull stress monitoring system was installed on upper deck to prove LNGC stable in the criteria to be less than 40MPa during the period of repair procedure. A temperature measuring system was also installed to exclude the additional stress due to thermal effect from the measured hull stress. As a result, the hull stress was modified with the data measured by the temperature measuring system. This hull stress considering thermal effect was used as a guide stress to check the safety of LNGC during the period of repair procedure.

• Korean Journal of Remote Sensing
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• v.20 no.3
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• pp.153-162
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• 2004

In the summer of 1998-2001, a huge flood occurred in the Yangtze River in the eastern China. Low salinity water less than 28 psu from the river was detected around the southwestern part of the Jeju Island, which is located in the southern part of the Korean Peninsula. We studied how to detect low salinity water from the Yangtze River, that cause a terrible damage to the Korean fisheries. We established a relationships between low salinity at surface, turbid water from the Yangtze River and digital ocean color remotely sensed data of SeaWiFS sensor in the northern East China Sea, in the summer of 1998, 1999, 2000 and 2001. The salinity charts of the northern East China Sea were created by regeneration of the satellite ocean color data using the empirical formula from the relationships between in situ low salinity, in situ measured turbid water with transparency and SeaWiFS ocean color data (normalized water leaving radiance of 490 nm/555 nm).

• Journal of Sensor Science and Technology
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• v.25 no.2
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• pp.86-90
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• 2016

A 3D ultrasonic anemometer measures the direction and velocity of wind in a 3D space. The 2D ultrasonic anemometers developed by different manufacturers do not differ significantly in terms of their form or structure. The 3D ultrasonic anemometers, on the other hand, have more diverse forms than their 2D counterparts depending on the measurement algorithms and methods. Designing and reviewing the structure at the initial stage and defining its performance objectives are time-consuming processes. The process can be made cost-effective and time-saving if the validity is tested by model design and structural interpretation, and the structure is designed to withstand high wind velocities. This study presents the results of a 3D ultrasonic anemometer on real sample data by using a 3D modeling program, CATIA, for ultrasonic anemometer modeling.

• Journal of Internet Computing and Services
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• v.12 no.2
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• pp.29-36
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• 2011

In this paper, NMEA based Parser programming for Smart-phone was designed at a GPS receiver. The design scheme for Map API and sensor web services was designed according to the Google Map API standards that the position values of NMEA sentences were changed due to XML files. As a result of interfaces between GPS NMEA sentences of Smart-phone and Google Map API, it is possible that real time visual positioning sensor web services about the Google Map mapping from a GPS receiver could be worked on web sever.

• Journal of Ocean Engineering and Technology
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• v.37 no.1
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• pp.38-48
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• 2023

To maintain the existing systems of ships and introduce autonomous operation technology, it is necessary to improve situational awareness through the sensor fusion of the automatic identification system (AIS) and automatic radar plotting aid (ARPA), which are installed sensors. This study proposes an algorithm for determining whether AIS and ARPA signals are sent to the same ship in real time. To minimize the number of errors caused by the time series and abnormal phenomena of heterogeneous signals, a tracking method based on the combination of the unscented Kalman filter and probabilistic data association filter is performed on ARPA radar signals, and a position prediction method is applied to AIS signals. Especially, the proposed algorithm determines whether the signal is for the same vessel by comparing motion-related components among data of heterogeneous signals to which the corresponding method is applied. Finally, a measurement test is conducted on a training ship. In this process, the proposed algorithm is validated using the AIS and ARPA signal data received by the voyage data recorder for the same ship. In addition, the proposed algorithm is verified by comparing the test results with those obtained from raw data. Therefore, it is recommended to use a sensor fusion algorithm that considers the characteristics of sensors to improve the situational awareness accuracy of existing ship systems.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.489-490
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• 2021

본 연구에서는 해양사고 처리 중 발생하는 인명사고 발생률을 감소시키고, 효율적으로 양식장을 관리하는 것을 전제로 카메라와 센서를 다기능 해양탐사 로봇에 적용하고자 한다. 현재의 양식장 관리 시스템은 수온 체크만 할 수 있게 되어있다. 이러한 시스템은 양식어에게 적합한 환경을 제공해주기 쉽지 않다. 본 논문은 이러한 문제점들을 개선하기 위해 기존의 해양 처리시스템과 양식 시스템 대신 카메라와 수온 센서, pH 농도 센서, 초음파 거리 센서, DC 모터, 블루투스 모듈을 적용한 다기능 해양탐사 로봇 기술을 제안한다. 기존의 시스템과는 다르게 안전하고 효율적으로 환경을 분석하고, 제어할 수 있다.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.2
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• pp.127-134
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• 2016

This paper presents practical issues for test and evaluation(T&E) methods to develop defense systems. Our argument is motivated by several domestic defense cases and the cases lead us to discuss two main factors for reliable defense systems development: 1) statistical approaches and 2) technical schemes. Specifically, statistical approaches enable to provide credible interpretations about T&E results in the decision-making process. With practical T&E results of the “Red Shark” torpedo, we performed statistical hypothesis tests and suggest a minimum sample size to accept the hypothesis. Next, technical schemes have more direct effects on improving reliability of developed defense systems and we shortly introduce tools development for systems verification that is required to integrate several sub-systems, e.g., combat, sensor, weapon, and communication systems, within a defense system. We additionally summary some domain cases using modeling and simulation techniques for successful T&E. In closing, we expect that the paper shows empirical investigation and lessons learned with these two practical issues, which provides a guide those who desire to make decisions about reliable defense systems development.