• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.9
• /
• pp.1275-1278
• /
• 2021

Nowadays, fake news from newspapers and social media is a serious issue in news credibility. Some of machine learning methods (such as LSTM, logistic regression, and Transformer) has been applied for fact checking. In this paper, we present Transformer-based fact checking model which improves computational efficiency. Locality Sensitive Hashing (LSH) is employed to efficiently compute attention value so that it can reduce the computation time. With LSH, model can group semantically similar words, and compute attention value within the group. The performance of proposed model is 75% for accuracy, 42.9% and 75% for Fl micro score and F1 macro score, respectively.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.2070-2071
• /
• 2007

본 연구에서는 변압기의 주 소음원인이 되는 120[Hz]와 240[Hz]및 360[Hz] 주파수에 대한 다중음/단일채널 적응 능동제어기법을 이용한 능동 제어시스템을 구성하였다. 이 능동 제어시스템을 이용하여 변압기에서 발생되어 나오는 소음을 저감시켰고 모의실험을 통해 소음이 감쇄되는 것을 확인하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.23 no.3
• /
• pp.194-198
• /
• 2010

Recently as the electronic devices are getting to be more and more smaller, transformers are needed to be micro fabricated using MEMS technology. In this paper transformers have been fabricated and measured by depositing insulation layer to reduce the loss of eddy current and in the middle core a high permeability permalloy was designed based on the turns ratio between primary coil and secondary coil which are 1:1 transformers. (the number of turns of primary coil and secondary coil: 3/3, 5/5, 7/7). The size of the transformers including ground shield are $1mm{\times}1.5mm$, $1mm{\times}1.95mm$, $1mm{\times}2.35mm$ respectively. The line width, pitch and the height of post are 50um. Based on the measured data from the micro fabricated transformers, the 3/3 turns in the primary coil and secondary coil showed the lowest insertion loss with 1.5 dB at 480 MHz and the 7/7 turns in the primary coil and secondary coil showed the highest insertion loss with 2.5 dB at 280 MHz. Also confirmed that the bandwidth goes up as the number of turns goes down. There was some difference between the actual measured data and the HFSS simulation result. It looks as if it is an error of the difference between oxidation of copper or the permeability of SU-8.

• Proceedings of the KIPE Conference
• /
• 2002.07a
• /
• pp.228-232
• /
• 2002

In this paper, In order to solve the problem is proposed using a new type of electronic ballast that the traditional magnetic ballasts operated at 50-60Hz have been suffered from noticeable flicker, high loss, large crest factor and heavy weight which is composed of rectifier, active power corrector, series resonant half bridge inverter, micro-controller and piezoelectric transformer for driving for driving T5 fluorescent lamp were manufactured. The proposed electronic ballast operated at high frequency (about 75kHz) shows a input power factor of more than 0.995, total harmonic distortion of less than $12\%$ and lamp current crest factor of less than 1.5, respectively. Output power and efficiency showed 28w and $85\%$, respectively. Accordingly, it is considered that the ballast using piezoelectric transformer can replace the typical electronic ballast.

• Proceedings of the KIEE Conference
• /
• 2001.07a
• /
• pp.464-466
• /
• 2001

In this paper, we developed the on-line Data Aquisition System(DAS) of distribution transformers using the hardware and monitoring program. The DAS consists of the top oil temperature sensing part, ambient temperature sensing part, load current sensing part, acoustic emission peak-value sensing part, acoustic emission pulse counter part, micro-processor part and wireless communication part. The Monitoring System consists of the communication setting, online monitoring and database construction part. The DAS send the data acquired from the some sensors of the distribution transformers to the host PC. The monitoring program of the host PC stores the data to database. And the monitoring system estimates the loss of life time for distribution transformer from the DB. Thus, it could be managed the career and the functional lifetime of the transformer more efficiently than existing methodologies.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.15 no.5
• /
• pp.61-67
• /
• 2001

Magnetic flux saturation dependent on phase of initial input power to high voltage transformer used in Micro wave oven. To limit inrush current high voltage transformer the relay contact should be ˝ON˝ when the lowest point of input voltage phase. The improved circuit is form compensating interrupt signal Micom input so the relay contact can be ˝ON˝ when the inrush current is lower. Test results are presented that improved circuit satisfies the limit 50[A] of requirement for input voltage variation mode. And the result verified by statistical method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.166-167
• /
• 2008

현재 Passive component 중의 하나인 트랜스포머의 소형화가 큰 이슈로 대두되고 있다. 본 논문에서는 기판의 와전류 효과의 영향을 줄이기 위해 LTCC기판을 이용하여 트랜스포머를 설계하고, 1:1 및 1:n의 권선 수를 갖는 두 코일의 인덕턴스 및 상호 인덕턴스를 시뮬레이션 하였다. 트랜스포머의 최대 크기는 2.55mm $\times$ 1.1 mm 이고 선폭은 50um 선간 간격은 50um이고, 기둥의 높이는 40um이다. MEMS 기술을 사용하여 기판 커플링과 저항손을 줄임으로서 8.5GHz 에서 0.33dB의 낮은 삽입 손실을 나타냈다.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.1
• /
• pp.333-344
• /
• 2018

This proposed paper aims for the high efficiency contactless power transfer in household dc power distribution. A 300 W five-level diode clamped multi-level converter with 300 Vdc input dc link bus is employed for the power transferring task and the output voltage range is controlled at 48 Vdc. The inner and outer solenoid coils are used for inductive power transfer (IPT) transformer with the 200 kHz switching frequency for designed power density. Therefore, to achieve the converter efficiency above 95%, the LLC series resonant with fundamental harmonic analysis (FHA) and the calculated switching angles are used as an optimized tool for designing the system resonant tank. The validations of this approached topology are illustrated in both MATLAB/Simulink simulation and implementation.

• Journal of the Korean Solar Energy Society
• /
• v.34 no.2
• /
• pp.16-23
• /
• 2014

This paper presents a renewable energy configuration plan of Micro grid in Gapa Island. To analyze the characteristics of Micro grid, BESS (Battery Energy Storage System), PMSG (Permanent Magnet Synchronous Generator) and SCIG (Squirrel Cage Induction Generator) are first modelled. The PMSG and SCIG will operate with basis on the real power curve. when the total power demand is larger than the total power generation, the BESS will be operated and the SOC (State Of Charge) is reduced. If the value of SOC could drop down to limited value, the system may be broken because of the voltage drop of BESS. To solve this problem, a DG (Diesel Generator) is used to charge the BESS and keep the voltage value of BESS with in a allowance limit. This paper represents simulation result when PMSG, SCIG connected to the Micro grid installed in Gapa Island. The simulation is carry out by using PSCAD/EMTDC program with actual line constant and transformer parameter in Gapa Island.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.1
• /
• pp.1-6
• /
• 2009

Air core based transformers have been designed, simulated and fabricated by using micromachining process for the application of wireless power transmission with the range of frequency from 1 GHz to 20 GHz. Fabricated transformers are the types of solenoid transformers with primary and secondary coils. the size of fabricated transformer is $1.1{\times}1.5{\sim}2.15\;mm$ including ground shield. Transformers have been measured by dividing two groups based on the turns ratio between primary coil and secondary coil which are 1:1 transformers(the number of turns of primary coil and secondary coil: 3/3, 5/5, 7/7) and l:n transformers(the number of turns of primary coil and secondary coil: 3/3, 3/6, 3/9). As a result of the measurement, the lowest insertion loss of transformers ranged from 2 dB to 2.8 dB according to the number of turns between primary coil and secondary coil. And the lowest insertion loss from the transformers was measured at the frequency from 7 GHz to 11 GHz according to the number of turns between primary coil and secondary coil. Based on the measurement data from the microfabricated transformers, the transformer with the 3/3 turns in the primary coil and secondary coil showed best performance compared to others in terms of lowest insertion loss, lowest insertion loss frequency and bandwidth.