• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.25-31
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• 2004

In order to prepare for the large power diesel vehicle, the current trend of advanced nations is to shift from the aluminum alloy piston to the steel piston. In this research, a steel forging piston which replaces the aluminum alloy piston is developed to improve the power performance of the diesel engine. The three dimensional flow and combustion analysis of the target engine is conducted. Using the result of the analysis, the piston is optimized, and a prototype of the articulated steel forging piston is built. The reliability of the piston has been evaluated through durability test using a Hydropuls Test Machine for 300,000 km.

• Journal of Hydrogen and New Energy
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• v.28 no.3
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• pp.273-278
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• 2017

In this paper, a fuel cell battery charger system, which is capable of bi-directional power transmission without built in battery, has been designed and fabricated. Performance and states of the notebook battery in bi-directional power transmission using the manufactured system have been tested. Before initializing the fuel cell charging system for 1 minute, the system received 10 W of electric power from notebook battery. Then the fuel cell charging system has been normal charging to notebook battery by 50 W. As a result of the experiment, the state of the notebook battery discharged less than 5% at the initial charging time, but then it has been charged. This results proves bi-directional power transmission in notebook computers increase the availability of fuel cell chargers.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.964-967
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• 2006

Korea Railroad Research Institute (the following 'KRRI') built AGT test line in Gyeong San-city, Kyongsang-bukdo province, Korea on August, 2004. This test line is exclusively used for the test of the driverless rubber-tired AGT system, and applied with research result of AGT System Development Project like vehicles, power supply, control and signaling, track and infrastructure system. The test line is available for the test of rubber tired AGT system's performance, function, safety. In this paper, we described the operation system of test line for the test of performance, safety, reliability, and also system operation in emergency. Finally we present the operation result of test line.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.177-187
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• 2001

It is important to test and evaluate the variation degree of ship-mounted antenna radiated power with respect to all directions in order to use more effectively antennas that installed on naval ships. The naval ship has various sensors for navigation, communication and electronic warfare, etc. And the performance of these sensors extremely depends on the various characteristics of antenna system to transmit and receive electromagnetic wave. The radiated power pattern of the antenna differs from all aspect angles of the ship because of complex superstructures. It is important to know the weak point(direction) of antenna radiation for appropriate operation. Therefore, the ARP(Antenna Radiation Pattern) of shipboard antennas is measured for the all aspect angles. The results of ARP measurement are utilized as reference for antenna arrangement of newly-built same class warship. This study also describes the development results for the ARP measurement technique, software design and test procedures to measure the radiation pattern of communication equipment antennas using the fixed test site.

• New & Renewable Energy
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• v.5 no.2
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• pp.31-38
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• 2009

The performance test of a wind turbine in a wind farm is generally carried out by the owner to verify the power curve of the wind turbine given by the turbine manufacturer. The international electro-technical commission provides the IEC 61400-12-1 standard on "Power performance measurements of electricity producing wind turbines". By using this code, one can easily find the suitable met-mast (meteorological mast) location for the wind data whether a wind farm is potential or already built. In this paper, the valid sectors for wind turbines installed in the HanKyoung wind farm, south-west in Jeju island are analyzed on the basis of the code by considering the wind farm layout. Among these sectors, the optimal met-mast location is presented for the power curve verification of the wind farm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.2028-2037
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• 2009

This paper presents the simulator for dynamic modeling of a MT(micro turbine) during start-up period. The simulator is implemented by modeling a dynamic power of main components of a MT including compressor, combustor and turbine. A modeling for a MT under steady state operation can be accurately built from thermodynamics analysis. But dynamic modeling during start-up period is very difficult because efficiency of main components is very low and the designed value has big error and nonlinear characteristics during start-up. In this paper, new method without using thermodynamics analysis during start-up is proposed for the simulator. The power models of main components are derived from analysis of the experimental operation data by test motoring using a electric starter under constant power output. The simulator is developed using MATLAB/Simulink. For constant power output control, sensorless vector inverter is designed and algorithms for starting from stall and method for controling a output power are proposed. The performance of developed simulator is verified by comparing experimental and simulation start-up results.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.4
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• pp.218-224
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• 2004

We present a miniature Direct Methanol Fuel Cell (micro-DMFC) using platinum sputtered microcolumn electrodes with a limited amount of fuel. We use the microcolumn electrode in order to improve the power density of the micro-DMFC that consists of two electrodes and polymer electrolyte. We also design the built-in fuel chamber in the anode for the portable electronics applications. We design and fabricate both microcolumn and planar electrodes, having an identical projective area of 5mm${\times}$5mm. The diffusion current density of the microcolumn electrode is 1.73 times higher than that of the planar electrode at electrode potential of 1.1V in the half-cell test. The micro-DMFC based on the microcolumn electrodes shows the maximum power of 10.8$\pm$7.54㎼(43.23$\pm$0.16㎼/$\textrm{cm}^2$) at the projective area of 5mm${\times}$5mm, while the planar electrode micro-DMFC shows the maximum power of 0.81$\pm$0.42㎼(3.24$\pm$1.68㎼/$\textrm{cm}^2$) at the same projective area. The micro-DMFC based on the microcolumn electrodes shows 13 times higher power density that the micro-DMFC based on the planar electrodes does.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.6 s.348
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• pp.30-37
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• 2006

This paper presents a modified scan cell architecture to reduce the power dissipation during testing. It not only eliminates switching activities in the combinational logic during scan shifting but also reduces switching activities in the scan chain during the time. Furthermore, it limits the transitions on capture cycles. It can be made for test-per-scan BIST and employed in both single scan style and multiple scan style. Experimental results demonstrate that the proposed structure achieves the same fault coverage with lower power consumption compared to other existing BIST schemes.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.2
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• pp.123-132
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• 2014

The maritime sector is advancing with dedicated endeavor to reduce greenhouse gas in addressing issues with regards to global warming. Since 01 January 2013, the International Maritime Organization (IMO) regulation mandatory requirement for Energy Efficiency Design Index (EEDI) has been in place and should be satisfied by newly-built ships of more than 400 gross tonnage and the Ship Energy Efficiency Management Plan (SEEMP) for all ships type. Therefore, compliance to this necessitates planning during the design stage whereas verification can be carried-out through an acceptable method during sea trial. The MEPC-approved 2013 guidance, ISO 15016 and ISO 19019 on EEDI serves the purpose for calculation and verification of attained EEDI value. Individual ships EEDI value should be lower than the required value set by these regulations. The key factors for EEDI verification are power and speed assessment and their synchronization. The shaft power can be measured by telemeter system using strain gage during sea trial. However, calibration of shaft power onboard condition is complicated. Hence, it relies only on proficient technology that operates within the permitted ISO allowance. On the other hand, the ship speed can be measured and calibrated by differential ground positioning system (DGPS). An actual test on a newly-built vessel was carried out to assess the correlation of power and speed. The Energy-efficiency Design Index or Operational Indicator Monitoring System (EDiMS) software developed by the Dynamics Laboratory-Mokpo Maritime University (DL-MMU) and Green Marine Equipment RIS Center (GMERC) of Mokpo Maritime University was utilized for this investigation. In addition, the software can continuously monitor air emission and is a useful tool for inventory and ship energy management plan. This paper introduces the synchronization and identification method between shaft power and ship speed for EEDI verification in accordance with the ISO guidance.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.765-768
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• 2003

In the end of a production line a new built power converter has to undergo a series of stress tests. This can be achieved by connecting it to a dynamometer consisting of a three-phase machine joined by a rigid shaft to a DC load machine. The latter is controlled to create some specific load characteristic needed for the test. In this paper a test method is proposed, in which no mechanical equipment is needed. The suggested test stand consists only of a converter to be tested and a simulator converter. Both devices are connected back-to-back on the AC-side via smoothing reactors. The simulator operates in real-time as an equivalent load circuit, so that the device under test will only notice the behaviour of a three-phase machine under consideration of the load.