• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.7
• /
• pp.1725-1728
• /
• 2009

This research developed process control device and FGV pattern generating device essential for full gate visual inspection to improve process so that defect detection capability may be maximized in specified environment. The devices developed in this research, which can be swiftly replaced in case loss or error occurs, are anticipated to improve module yield as well as maintain tact loss near '0'. In addition, as a result of mounting H/W and S/W system to control detailed operation sequence in production line and executing performance check and verification, detection rates were 98.1% and 99.1% respectively for pixel defect by tact and line defect, and yield of the entire module process including gate and visual level test increased up to 98.3%.

• Nuclear Engineering and Technology
• /
• v.49 no.5
• /
• pp.968-978
• /
• 2017

Three small-break loss-of-coolant accident (SBLOCA) tests with safety injection pumps were carried out using the integral-effect test loop for SMART (System-integrated Modular Advanced ReacTor), i.e., the SMART-ITL facility. The types of break are a safety injection system line break, shutdown cooling system line break, and pressurizer safety valve line break. The thermal-hydraulic phenomena show a traditional behavior to decrease the temperature and pressure whereas the local phenomena are slightly different during the early stage of the transient after a break simulation. A safety injection using a high-pressure pump effectively cools down and recovers the inventory of a reactor coolant system. The global trends show reproducible results for an SBLOCA scenario with three different break locations. It was confirmed that the safety injection system is robustly safe enough to protect from a core uncovery.

• Journal of Information Processing Systems
• /
• v.15 no.5
• /
• pp.1156-1170
• /
• 2019

In recent years, the problem of data drifted of the smart grid due to manual operation has been widely studied by researchers in the related domain areas. It has become an important research topic to effectively and reliably find the reasonable data needed in the Supervisory Control and Data Acquisition (SCADA) system has become an important research topic. This paper analyzes the data composition of the smart grid, and explains the power model in two smart grid applications, followed by an analysis on the application of each parameter in density-based spatial clustering of applications with noise (DBSCAN) algorithm. Then a comparison is carried out for the processing effects of the boxplot method, probability weight analysis method and DBSCAN clustering algorithm on the big data driven power grid. According to the comparison results, the performance of the DBSCAN algorithm outperforming other methods in processing effect. The experimental verification shows that the DBSCAN clustering algorithm can effectively screen the power grid data, thereby significantly improving the accuracy and reliability of the calculation result of the main grid's theoretical line loss.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.3
• /
• pp.451-456
• /
• 2007

This paper presents a problem that reconfigure distribution power system using branch exchange method. Optimal reconfiguration problem calculates line loss, voltage condition about system states of all situations that become different according to line On/off status, and search for optimum composition of these. However, result is difficult to be calculated fast. Because radiated operation condition of system is satisfied using many connection and sectionalize switches in the distribution power system. Therefore, in this paper, optimization method for reducing system total loss and satisfying operating condition of radial and constraints condition of voltage is proposed using the fastest branch exchange. And optimal solution at branch exchange algorithm can be wrong estimated to local optimal solution according to initial operating state. Considering this particular, an initial operating point algorithm is added and this paper showed that optimal solution arrives at global optimal solution.

• Proceedings of the KIEE Conference
• /
• 2008.09a
• /
• pp.72-75
• /
• 2008

The Electromagnetic Interference(EMI) in railway applications is largely due to doing the power conversion for traction and Auxiliary system on the Highspeed Electric Multiple Unit-400X(HEMU-400X). In order to research on EMI in railway applications, it were included how much the HEMU-400X generates it and it has an effect on the equipments of electric system which resulted from Power Line Disturbance (PLD) phenomenon by the loss of contact during its running. In this study, the dynamic characteristic of a contact wire and pantograph suppling electrical power to high-speed trains are investigated. The analysis of the loss of contact based on Power Simulator program software is performed to develop power line disturbance model suitable for high speed operation. It is confirmed that a contact wire and pantograph model are necessary for studying the dynamic behavior of the pantograph system.

• Journal of Power Electronics
• /
• v.8 no.4
• /
• pp.345-353
• /
• 2008

In this paper, a novel loss minimization of an induction generator in wind energy generation systems is presented. The proposed algorithm is based on the flux level reduction, for which the generator d-axis current reference is estimated using support vector regression (SVR). Wind speed is employed as an input of the SVR and the samples of the generator d-axis current reference are used as output to train the SVR algorithm off-line. Data samples for wind speed and d-axis current are collected for the training process, which plots a relation of input and output. The predicted off-line function and the instantaneous wind speed are then used to determine the d-axis current reference. It is shown that the effect of loss minimization is more significant at low wind speed and the loss reduction is about to 40% at 4[m/s] wind speed. The validity of the proposed scheme has been verified by experimental results.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.3A
• /
• pp.311-317
• /
• 2004

A low loss reflection type analog phase shifter which is realized with two varactors and branch coupler. is described. A new design technique for the large phase shift is applied using short stub microstripe lines. This paper presented the realization of design and experimental results. Through the experiment using the duroid microstrip line and varactors, the phase of 2.26GHz signal is controlled to the DC voltage with the phase shift range of 170$^{\circ}$. The achieved insertion loss of less than 3㏈ and the return loss of mote than 12㏈ are achieved over all phase states.

• Journal of Industrial Technology
• /
• v.21 no.A
• /
• pp.207-211
• /
• 2001

For the power line communication, we studied its characteristic impedance, noise characteristics, loss characteristics and the coupling circuit between the communication MODEM and power lines. As the results of the experiments, we concluded that the power line impedance in a house varied in the wide range because the electric systems generate the current and voltage hamornic noises.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.7 no.6
• /
• pp.38-47
• /
• 2008

In this paper, the narrow band-pass filter with compact-size using the ${\lambda}g/2$ open stubs is proposed. The filter size is reduced by realization of transmission line at second harmonics and at the same time the power can be transferred to the output by using the fundamental wave generated in the resonator and the transmission line in which the impedance mismatch technique is adopted. Thus, the proposed filter can be reduced to half-length of horizontal transmission line than the conventional one. The experimental results show that insertion loss is 1.58 dB and return loss is 9.86 dB, and the fractional bandwidth is 10 % at the center frequency of 5.8 GHz. The filter size is $10.34{\times}18.56\;mm2$.

• Journal of Advanced Marine Engineering and Technology
• /
• v.36 no.1
• /
• pp.149-156
• /
• 2012

In this study, we propose a novel transmission line employing inverted PACD (Periodically Arrayed Capacitive Devices) for application to a development of miniaturized passive components on MMIC. The novel microstrip line employing Inverted PACD structure showed a loss much lower than conventional microstrip line. Using the inverted PACD structure, we fabricated a miniaturized impedance transformer on MMIC. the size of the impedance transformer was 0.012 $mm^2$, which is only 1.7% of conventional one. The impedance transformer showed good RF performances in a frequency range of 2.25~6.5 GHz.