• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2999-3004
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• 2010

In comparison with some other light sources, LED has merits such as long lifetime, pollution free, and high energy efficiency. Lately, due to development of LED with high brightness and capacity, LED, which has been applied in display system only, has applied in the field of lighting system. As power LED for lighting system can be burned out by heat problem, the driving current of power LED has to be controlled below the designed value. In this paper, power LED photovoltaic lighting system, which has the current limitting function, has been described. After photovoltaic power is generated from PV panel. it is charged into a battery. And then, after the charged power is converted to DC24[V] through a boost DC-DC converter, it is supplied to power LED at night. It has been validated by designing and testing of 72[W] power LED lighting system, which includes a PV charger, a boost DC-DC converter and a current limiter for driving power LED.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4483-4488
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• 2010

In comparison with some other light sources, LED has merits such as long lifetime, pollution free, and high energy efficiency. Lately, due to development of LED with high brightness and capacity, LED, which has been applied in display system only, has applied in the field of lighting system. Driving current of power LED has to be controlled below the designed value. In this paper, half-bridge LLC series resonant converter, which has the current limiting function, has been described. Half-bridge LLC series resonant converter allows in relatively wide input voltage and output load range when compared to the other resonant converter. Also, it is possible to reduce a magnetic component, because leakage inductance of transformer is used as a resonant inductance. It has been validated by designing and testing 200[W] half-bridge LLC converter of DC24[V] output voltage for LED lamp driver, which includes a current limiting function and power factor correction(PFC) function.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.168-171
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• 2006

The Korean Solar Thermal Industry hopes to realize 1 Million Solar Thermal Roofs. According to the 2nd Renewable Basic Plan : 2003-2012 the Government showed a very aggressive Solar Thermal Deployment Plan including Solar Thermal Apartment Housings Program. Owing to the Vision Statement such as Million Solar Thermal Roofs Program Korean Solar thermal Industry also can bring another shinny days Especially the more solar thermal applications such as to the Apartment Housings and Green Villages could bring a sustainable Solar Society Korea The RPA Program by the 9 Major Non-Private Energy Corporal ions and the RPS Program for the Solar Thermal Energy shall be another useful policy for the realization of Million Solar Korea era.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.367-372
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• 2001

A fuel cell is an electrochemical energy conversion device tint converts hydrogen and oxygen into electricity and heat for hot water and heating room A fuel cell provides a DC voltage tint can be used to power motors, lights or any number if electrical appliances. There are several different types if fuel cells, each using a different chemistry. Some types if fuel cells show promise for use in DC (distributed generation) because fuel cell is very clean and efficient energy device. CETI (Clean Energy Technologies, Inc.) is developing PEMFC and DMFC for residential power generation, portable and battery. It is anticipated tint RPG is advantageous over current power generation by utility In terms if economics assuming the lifetime of major components is at least five years.

• Korean Journal of Computational Design and Engineering
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• v.4 no.1
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• pp.32-42
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• 1999

Approximate lofting or skinning is one of practical surface modeling techniques well used in CAD and reverse engineering applications. Presented in this paper is a method for approximately lofting a given set of curves wihin a specified tolereance. It is based on refitting input curves simultaneously on a common knot vector and interpolating them to get a resultant NURBS surface. A concept of reducing the number of interior knots of the common knot vector is well adopted to acquire more compact representation for the resultant surface. Energy minimization is newly introduced in curve refitting process to stabilize the solution of the fitting problem and get more fair curve. The proposed approximate lofting provides more smooth surface models and realizes more efficient data reduction expecially when the parameterization and compatibility of input curves are not good enough. The method has been successfully implemented in a new CAD/CAM product VX Vision? of Varimetrix Corporation.

• Journal of Ship and Ocean Technology
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• v.3 no.1
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• pp.12-26
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• 1999

A new concept of collision energy absorbing system for ;he New Oil-tankers with Advanced Double Hull Structure(NOAHS and NOAHS II) are presented through the joint-research pro-gran between Inha and Hamburg-Harburg University. A comparative study on col vision resistance of these proposed side structures with standard double hull structure of 310K DWT class VLCC, is carried out. The fatigue investigation of structural detail parts is also included. It contains a comparative fatigue study based on pertinent regulations of Classification Societies.

• Tunnel and Underground Space
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• v.26 no.1
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• pp.24-31
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• 2016

Recently, many studies have been conducted to use fixed-wing and rotary-wing unmanned aerial vehicles (UAVs, Drones) for topographic surveying in open-pit mines. Because the fixed-wing and rotary-wing UAVs have different characteristics such as flight height, speed, time and performance of mounted cameras, their results of topographic surveying at a same site need to be compared. This study selected a construction site in Yangsan-si, Gyeongsangnam-do, Korea as a study area and compared the topographic surveying results from a fixed-wing UAV (SenseFly eBee) and a popular rotary-wing UAV (DJI Phantom2 Vision+). As results of data processing for aerial photos taken from eBee and Phantom2 Vision+, orthomosaic images and digital surface models with about 4 cm grid spacing could be generated. Comparisons of the X, Y, Z-coordinates of 7 ground control points measured by differential global positioning system and those determined by eBee and Phantom2 Vision+ revealed that the root mean squared errors of X, Y, Z-coordinates were around 10 cm, respectively.

• Bulletin of the Korea Photovoltaic Society
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• v.6 no.1
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• pp.21-34
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• 2020

Sri Lanka has strongly understood the importance of mitigation of climate change and various measures have been taken. To tackle the climate change, after ratifying Paris Agreement, Sri Lanka has pledged to reduce her greenhouse gas emission in the energy sector by 20% (16% unconditional and 4% conditional) by 2030 based on the BAU scenario. Simultaneously, the government introduced its new energy policy and strategies in 2019 with a vision of achieving carbon neutrality by 2050. This paper survey related key government documents, policies, reports, and academic articles to investigate opportunities for the private sector to invest large scale solar power deployment (10 MW or above) and to get support from climate finance under article 6 of the Paris Agreement. It has found, growing concern on the environment, energy security issues and increase import expenses for fossil fuels are the main influencing factors to move renewable sources. Further, government investment and FDI both have gradually decreased in the energy sector. Therefore, an alternative financing mechanism is needed. Although the private sector allowed investing in the energy sector since 1996 with the introduction of IPP (Independent Power Producers), it could not make considerable progress on involving large scale solar utility projects. This has revealed government policy is not aligning with the long term generation plan of the electricity sector. The study has also found, it needs more strategic road map, coordination with different institutions, monitoring system to enhance large scale solar contribution.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2307-2310
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• 2005

A pressurizer is one of the major safety related equipment of nuclear power plants. In order to inspect and maintain the internal structures of a pressurizer, jumpers have to enter the pressurizer, in spite of the high dose exposure. Therefore, a tele-operated robotic manipulator has been developed, which consists of four parts with 2DOFs arms, a gripper, base frame, and control console. The task of this robotic manipulator is to extract the damaged electric heaters and inspect the internal structure of the pressurizer. The gripper hanging from the manipulator approaches the heaters and extracts the damaged heater by using a self-locking mechanism. In order to investigate the structural stability of the robotic manipulator, a stress analysis has been performed by using the ANSYS code. The results of this paper include the position control and vibration control of robotic gripper and the development of processing visual information for a vision sensor.

• Nuclear Engineering and Technology
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• v.46 no.4
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• pp.489-500
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• 2014

In this study, remote handling strategies for a large-scale argon cell facility were considered. The suggested strategies were evaluated by several types of field test. The teleoperation tasks were performed using a developed remote handling system, which enabled traveling over entire cell area using a bridge transport system. Each arm of the system had six DOFs (degrees of freedom), and the bridge transport system had four DOFs. However, despite the dexterous manipulators and redundant monitoring system, many operators, including professionals, experienced difficulties in operating the remote handling system. This was because of the lack of a strategy for handling the installed camera system, and the difficulty in recognizing the gripper pose, which might fall outside the FOV (field of vision) of the system during teleoperation. Hence, in this paper, several considerations for the remote handling tasks performed in the target facility were discussed, and the tasks were analyzed based on ergonomic factors such as the workload. Toward the development of a successful operation strategy, several ergonomic issues, such as active/passive view of the remote handling system, eye/hand alignment, and FOV were considered. Furthermore, using the method for classifying remote handling tasks, several unit tasks were defined and evaluated.