• Journal of Navigation and Port Research
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• v.31 no.10
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• pp.853-858
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• 2007

In this paper, a seesaw system composed with a moving cart on the rail and seesaw frame is made to demonstrate the effectiveness of the control theory. The control aim is to maintain an equilibrium of seesaw frame in spite of various initial conditions and an allowable disturbance. To solve this control problem, a PI-type state feedback controller using reduced-order observer is implemented and applied to the seesaw system. The reduced-order observer can be used to estimate the state variables in the case of the limit of sensor number or the constraint on setting sensors and the cost. A series of simulation are carried out to verify the effectiveness of the control system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.135-140
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• 2005

There are cofferdam and watertight wall to prevent of circulation or pollution during building of ocean structures like a dam and bridge in the harbors area and the sea. Inflow fluid and base of structure is important thing as one of the structural design factors for this interception wall like a cofferdam and watertight wall. In this study, it is revealed that at least 500 instantaneous velocity field data are required for ensemble average to get reliable turbulence statistics. The turbulent shear flow around a surface-mounted vertical wall was investigated by using the two-frame PIV(CACTUS 3.1) system and Mean velocity distributions have also been measured in the whole flow field.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.425-431
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• 2009

Recently, new technology has been introducing according to the efforts for maritime safety, traffic and environmental protection that uses electronic method to make use of maritime information effectively. To be associated with the tendance, international society which centered to IALA Introduces advanced technology of AtoN with Automatic Identification System(AIS) that it is crucial method to collect and transmit maritime data. This article is to thoroughly analyse and investigate the international and national regulation of related AtoN AIS, and propose to be included and applied into national radio-communication equipment regulation.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.4
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• pp.1159-1170
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• 2016

This study examines the distribution and taxonomy of sea horses in South Korea, specifically sea horses that were caught in the Southern Sea, centering on Yeosu, South Korea. Specimen collection methods The samples were collected by set net, skimming nets, dragnets, and landing nets on a boat, as well as scuba diving. A total of 128 sea horses belonging to three species were collected. To investigate the exact distribution pattern, the catch per unit effort and the population density per $1,000m^2$ were calculated for each site in the Southern Sea. The result shows the highest catch by set nets was 29 sea horses a day in Site B at Dolsan-eup, Port Impo, and the highest catch by scuba diving was 8 sea horses a day in Site B at Gijang-gun, Busan. The highest population density was 61.2 sea horses in the coast of Gijang-gun, Busan. Genetic information analysis and morphological analysis were performed for determination of species. As a result, four Hippocampus trimaculatus, (flat-faced sea horses), 45 Hippocampus coronatus (Crowned sea horses), and 79 Hippocampus mohnikei (Japanese sea horses) were distinguished.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.2
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• pp.21-31
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• 2010

This paper presents a design of PLL and SSCG for reducing the EMI effect at the electronic machinery and tools for DisplayPort application. This system is composed of the essential element of PLL and Charge-Pump2 and Reference Clock Divider to implement the SSCG operation. In this paper, 270MHz/162MHz dual-mode PLL that can provide 10-phase and 1.35GHz/810MHz PLL that can reduce the jitter are designed for 2.7Gbps/162Gbps DisplayPort application. The jitter can be reduced drastically by combining 270MHz/162MHz PLL with 2-stage 5 to 1 serializer and 1.35GHz PLL with 2 to 1 serializer. This paper propose the frequency divider topology which can share the divider between modes and guarantee the 50% duty ratio. And, the output current mismatch can be reduced by using the proposed charge-pump topology. It is implemented using 0.13 um CMOS process and die areas of 270MHz/162MHz PLL and 1.35GHz/810MHz PLL are $650um\;{\times}\;500um$ and $600um\;{\times}\;500um$, respectively. The VCO tuning range of 270 MHz/162 MHz PLL is 330 MHz and the phase noise is -114 dBc/Hz at 1 MHz offset. The measured SSCG down spread amplitude is 0.5% and modulation frequency is 31kHz. The total power consumption is 48mW.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.162-163
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• 2018

This study introduces the R&D project of development of the 1st LNG bunkering barge in Korea. The Design and pilot test of Barge-To-Ship 500cbm LNG bunkering barge system for coastal trading LNG-fueled ship is proposed. The following technologies will be developed from the project ; Basic/Detail design and pilot test of LNG Bunkering barge system, Basic/Detail design and pilot test of LNG bunkering process system considering LNG loading/unloading, Basic/Detail design and pilot test of 500cbm LNG tank in type-C, Evaluation of bunkering performance according to conditions (environment, SIMOPs) by numerical simulation, Performance evaluation of bunkering barge, towed barge and Barge-To-Ship motion considering ocean environment load, and scenario in Barge-To-Ship LNG bunkering. This project will contribute expansion to LNG-fueled ship industry and pave the way to establish LNG bunkering hub port.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.10
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• pp.59-68
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• 2013

This paper proposes the boost type bidirectional DC/DC converter with high efficiency for electric vehicle using an interleave method. This interleave method can reduce the system size because it reduces the ripple of output voltage and input current with no add to extra filter. Proposed system is consist of two converters and applies to interleaved method through phase shift to each converter. And it implements the high boost through voltage double and series construction of output port. Also, it reduces the price and increases the efficiency as operating the ZCS by leakage inductance of transformer and capacitor of voltage double with not add special reactor. Proposed DC/DC converter using interleave method is proved the validity through the result of PSIM simulation and experiment of 5kW DC/DC converter.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.3
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• pp.38-43
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• 2011

A CNG/diesel dual-fuel engine uses CNG as the main fuel and injects a small amount of diesel as an ignition priming. This study proposed the modification of the existing diesel engine into a dual-fuel engine that injects diesel with a high pressure by common rail direct injection (CRDI) and by injecting CNG at the intake port for premixing. And experiment was progressed for understanding about effect of CNG mixing ratio. The CNG/diesel dual-fuel engine showed equally satisfactory coordinate torque and power regardless of CNG mixing ratio. The PM emission was low at any CNG mixing ratio because of very small diesel pilot injection. In case of NOx and HC, high CNG mixing ratio showed low NOx and HC emissions at low speed. At medium & high speed, low CNG mixing ratio showed low NOx and HC emissions. Therefore, it would be optimized by controlling CNG mixing ratio.

• Special Issue of the Society of Naval Architects of Korea
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• 2007.09a
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• pp.14-21
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• 2007

A passenger ship is consist of five(5) constituents; passenger, sea, crew, port and ship itself and the rule & regulation which is applicable to passenger ship are differently required as their objects of constituents. the basic concept of rule & regulation can be defined all activities to keep safety of ship and her constituents. Especially, the rule & regulation for passenger ship design and construction shall be considered not only safety of ship itself but also safety of lives, so its are required more severe than commercial vessel. Recently, the IMO have finished the rule making work on the 'passenger ship safety' since it has been discussed last 2000 and next MSC meeting will be adopted the results. In this paper, the application method of rule & regulation are treated and the new rule which were made by IMO are introduced. The rule & regulation for passenger ship is one of the most important things. therefore, it is required to careful consideration to apply on the rule application.

• The Korean Journal of Pain
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• v.25 no.1
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• pp.47-51
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• 2012

Intrathecal drug administration system (ITDAS) can reduce the side effects while increasing the effectiveness of opioids compared to systemic opioid administration. Therefore, the use of ITDAS has increased in the management of cancer pain and chronic intractable pain. Catheter obstruction is a serious complication of ITDAS. Here, we present a case of catheter obstruction by a mass formed at the side hole and in the lumen. A 37-year-old man suffering from failed back surgery syndrome received an ITDAS implantation, and the ITDAS was refilled with morphine every 3 months. When the patient visited the hospital 18 months after ITDAS implantation for a refill, the amount of delivered morphine sulfate was much less than expected. Movement of the pump rotor was examined with fluoroscopy; however, it was normal. CSF aspiration through the catheter access port was impossible. When the intrathecal catheter was removed, we observed that the side hole and lumen of the catheter was plugged.