• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.7
• /
• pp.1211-1217
• /
• 2007

In this paper, a 10kVA PV inverter applying Incremental Conductance(IncCond) method for maximum power point tracking WIS developed and its performance tests were carried out. Modeling and simulation of PV array and system controller was performed using PSCAD/EMTDC, an electromagnetic transient analysis program. After comparison and analysis of Perturbation & Observation (P & O) and IncCond method, a PV inverter based on IncCond method was designed and manufactured. Grid interface transient characteristics including start-up, normal operation, and fault operation were tested, which verified the usefulness of the proposed system. In the near future, commercialization process will proceed through additional extensive tests of transients.

• Proceedings of the KIEE Conference
• /
• 2006.11a
• /
• pp.384-386
• /
• 2006

This paper deals with tests on the reactive power output limit and the Over-Excitation Limiter (OEL) dynamics of generation unit. The suggested reactive limit test methods can identify the allowable maximum/minimum reactive power at 100% rated MW in the steady-state operation condition. The on-line OEL limit test method can identify the time characteristics of OEL with the generation output at 50% of the rated MW. These methods are validated by applying to Yang-Yang Pumped storage units of 282 MVA.

• Proceedings of the KSRS Conference
• /
• 2004.10a
• /
• pp.287-290
• /
• 2004

In the moving object database system, spatiotemporal join is very import operation when we process join moving objects. Processing time of spatio-temporal join operation increases by geometric progression with numbers of moving objects. Therefore efficient methods of spatio-temporal join is essential to moving object database system. In this paper, we propose spatio-temporal join algorithm with TB-Tree that preserves trajectories of moving objects, and show result of test. We first present basic algorithm, and propose cpu-time tunning algorithm and IO-time tunning algorithm. We show result of test with data set created by moving object generator tool.

• Proceedings of the KIEE Conference
• /
• 1999.07c
• /
• pp.1397-1400
• /
• 1999

The function of newly developed equipments must be verified in real power system before they put into operation. However, it is hard to test them in real power system due to the possibility of abnormal operation. In this paper, test method for new relays is developed in order to simulate their function in real power system using RTDS (Real Time Digital Simulator) and the simulation results show the capability of method.

• ETRI Journal
• /
• v.23 no.2
• /
• pp.77-84
• /
• 2001

The detection of open defects in CMOS SRAM has been a time consuming process. This paper proposes a new dynamic power supply current testing method to detect open defects in CMOS SRAM cells. By monitoring a dynamic current pulse during a transition write operation or a read operation, open defects can be detected. In order to measure the dynamic power supply current pulse, a current monitoring circuit with low hardware overhead is developed. Using the sensor, the new testing method does not require any additional test sequence. The results show that the new test method is very efficient compared with other testing methods. Therefore, the new testing method is very attractive.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.05b
• /
• pp.745-750
• /
• 1996

An analysis of a loss of residual heat removal system (RHRS) event during midloop operation after reactor shutdown was performed using the RELAP5/MOD3 thermal-hydraulic computer code. The experimental data of a 5% cold leg break test conducted at the ROSA-IV Large Scale Test Facility (LSTF) to simulate a main coolant pump shaft seal removal event during midloop operation of a Westinghouse-type PWR were used in the analysis. The predicted core boiling time and the peak primary system pressure showed good agreements with the measured data. Some differences between the calculational results and the experimental results were, however, found in areas of the timing of loop seal clearing and the temperature distribution in a pressurizer. Other calculational problems identified were discussed as well.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.28 no.1
• /
• pp.115-121
• /
• 2020

Recently avionics equipment and its integration are most important part for implementing high performance aircraft system. This trends are emphasized in the military or special purpose aircraft development program. Flight Test Bed Aircraft (hereafter FTB A/C) - by modified commercial aircraft - was key solution to verify function and performance of avionics system for complex aircraft development program for a while, but there are no experience to use it in domestic airspace of ROK. This paper would like to address what act and regulation is necessary to perform flight operation of FTB A/C with keeping a airworthiness and airspace control policy. and then willing to propose what do we do for improving aviation industry.

• Journal of the military operations research society of Korea
• /
• v.30 no.2
• /
• pp.108-121
• /
• 2004

This paper deals with a procedure of changing the current inspection & replacement periods for ROKAF aircraft parts. ROKAF is mostly operating aircraft of foreign makes, and takes maintenance actions according to Technical Orders(TO.) published by foreign aircraft manufacturers. Therefore ROKAF inspects and replaces specific parts at the time noticed from T.O.. These inspection and replacement periods are determined by manufacturers according to the standard operating environment and parts' durability. But the standard operating environment Is different from operator's environment. Because of this difference, the inspection and replacement periods have to be changed according to operators' operation environment. It is resonable that the manufacturer, having design materials and life test data of parts, changes those periods together with materials of operators' operation environment. But we have many difficulties in obtaining the design materials and life test data. Then this paper proposes a procedure of changing the periods of aircraft's parts with life data obtained during operating aircraft. For the reliability analysis, a software of RELEST (Reliability Estimation Version 1.0) is used.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.13 no.1
• /
• pp.147-152
• /
• 2005

The exhaust system of automobile is faced with random or spectrum types of fatigue loads during usage life and so needs to be closely estimated for quality and performance to have enough certainty on design endurance lift during preliminary design process. Structural operation conditions, operation load history, property of material and manufacturing process etc. should be considered by performing experiment approach. Using the software program for predicting fatigue life quickly and exactly in preliminary design stage saves plenty of time and cost generated by fatigue tests. In this paper, fatigue life prediction was performed on the basis of fatigue analysis using MSC/FATIGUE and load data from field test and the life of development items was estimated and compared through the results.

• Journal of the Korea Society of Computer and Information
• /
• v.7 no.2
• /
• pp.19-33
• /
• 2002

In this Paper, we described the Parwan CPU using a VHDL at the behavioral level and then described by connecting CPU components at the dataflow level. Finally, we simulated to verify of execution of a CPU processor using a test-bench method. A presented design method was to enable information exchange of design and representation of operation were very exact and simple. Also. a documentation of design was available and it was easy that verify a operation of designed processor. The behavioral description of VHDL aids designer as we verify our understanding of the designed system, while the dataflow description can be used to verify the bussing and register structure of the design.