• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.1
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• pp.26-32
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• 2012

In this study, we proposed an intelligent algorithm for the performance improvement of ASK system for giga-bit modem in millimeter band. The proposed intelligent algorithm is a fuzzy logic system. The inputs to the fuzzy logic system are the remainder and integral of remainder that occurred counter of receiver, and the output is bandwidth of LPF. In order to verify the effectiveness of the proposed method, simulation is performed to the proposed system and the fixed bandwidth system, and is confirmed to the BER performance.

• Biomolecules & Therapeutics
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• v.28 no.6
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• pp.527-536
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• 2020

Liver fibrosis constitutes a significant health problem worldwide due to its rapidly increasing prevalence and the absence of specific and effective treatments. Growing evidence suggests that apoptosis-signal regulating kinase 1 (ASK1) is activated in oxidative stress, which causes hepatic inflammation and apoptosis, leading to liver fibrogenesis through a mitogen-activated protein kinase (MAPK) downstream signals. In this study, we investigated whether selonsertib, a selective inhibitor of ASK1, shows therapeutic efficacy for liver fibrosis, and elucidated its mechanism of action in vivo and in vitro. As a result, selonsertib strongly suppressed the growth and proliferation of hepatic stellate cells (HSCs) and induced apoptosis by increasing Annexin V and TUNEL-positive cells. We also observed that selonsertib inhibited the ASK1/MAPK pathway, including p38 and c-Jun N-terminal kinase (JNK) in HSCs. Interestingly, dimethylnitrosamine (DMN)-induced liver fibrosis was significantly alleviated by selonsertib treatment in rats. Furthermore, selonsertib reduced collagen deposition and the expression of extracellular components such as α-smooth muscle actin (α-SMA), fibronectin, and collagen type I in vitro and in vivo. Taken together, selonsertib suppressed fibrotic response such as HSC proliferation and extracellular matrix components by blocking the ASK1/MAPK pathway. Therefore, we suggest that selonsertib may be an effective therapeutic drug for ameliorating liver fibrosis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.9
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• pp.1087-1093
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• 2012

In this paper, we implemented a HF-band magnetic-field communication system consisting of an amplitude shift keying(ASK) transmitter, a pair of loop antennas, and an ASK receiver. Especially, we suggested a new ASK transmitter architecture, where a drain bias of class E amplifier is switched alternatively between two voltage levels with respect to input data. A maximum 5 W class E amplifier was designed using a low cost IRF510 power MOSFET at the frequency of 6.78 MHz. A measured sensitivity of the designed ASK receiver is -78 dBm, which consists of a log amplifier, a filter, and a comparator. Maximum communication range of magnetic-wave communication system with loop antennas was calculated using magnetic field equations in both near-field and far-field ranges. Also, in order to verify the calculated values, an indoor propagation loss was measured using a pair of loop antennas whose dimensions are $30{\times}30cm$. Maximum operating range is estimated about 35 m in case of transmitter's output power of 1 W and receiver sensitivity of -70 dBm, respectively. Finally, the communication field test using the designed ASK transmitter and receiver was successfully done at the distance of 5 m.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.755-758
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• 2003

본 논문에서 단거리전용통신(DSRC)용 OBE에 사용되는 5.8GHz 송신측 ASK와 PA를 one-chip화하여 MMIC로 설계를 및 제작하였다. 설계된 ASK-PA는 3V 단일 공급전원을 사용하였고, 능동 소자로서 GaAs MESFET을 사용하였다. ASK는 회로의 복잡도를 줄이기 위해 직접변조 방식을 채택하였고, 인접채널 간섭의 영향을 줄이기 위하여 드레인 제어 변조회로를 사용하였다. 또한 전력증폭기는 2단으로 하여 AB급으로 동작하도록 전압분배 바이어스회로로 구성하였다. 측정결과 3V의 공급전압에서 전체이득 20.63dB, 송신출력 7.8dBm으로 나타냈다. 공정은 ETRI 0.5㎛ GaAs MESFET 공정을 사용하였고, Chip size는 1.2mm×l.4mm이다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.33-40
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• 2011

In this paper, underwater acoustic communication experiment was carried out to test a performance of single carrier digital modulation schemes. The communication experiment was performed at real sea and tested modulation schemes are ASK, FSK with non-coherent detection and QPSK with coherent detection. A modulated image data was transmitted with data rates of 600bps~3Kbps. From the results of BER of the demodulated signal, ASK and FSK show the achievable BER of $10^{-3}{\sim}10^{-4}$ without compensation techniques and QPSK show that of $10^{-4}$ with linear equalizer.

• The Journal of the Korea Contents Association
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• v.6 no.1
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• pp.8-13
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• 2006

In this thesis, an automatic door lock system using a dual tone multiple frequency(DTMF) signal generated as pushing the key button of mobile phone is proposed and implemented. This system consists of a transmitter module and a receiver module for processing the DTMF signal of mobile phone. The DTMF signal of mobile phone connected with ear-phone jack enter into the input terminal of DTMF receiver and those are encoded by a code-converter with 4-bits binary format in the DTMF receiver. The encoded output signals are transmitted to the amplitude shift keying(ASK) modulator of transmitter module and the modulated ASK signals which are converted into radio frequency(RF) signals propagate in a free space. The RF signals passed through a free space are demodulated by the ASK demodulator of receiver module and the demodulated ASK signals are sent to a micro-controller unit(MCU). The output signals processed by the MCU are compared with the secreted identification number which is prerecorded in a microprocessor and are transferred to a power relay. If the result is the same, the automatic door lock system opens a door. In the opposite case, it maintains closing the door. The implemented automatic door lock system operates well in mobile environments.

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.2110-2112
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• 2010

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.10 s.101
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• pp.1020-1027
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• 2005

In this paper, economic miniature RF transmitter module for intelligent transportation system(ITS) is described. This module which consists of ASK modulator, frequency synthesizer, power amplifier is operating at 5.8 GHz frequency band and implemented by using LTCC process technique. Thus, ultra small size of 0.8 CC and improved electrical performances has been obtained. From the test results, transmitting characteristics of 10 dBm ouput power and -46 dBc interchannel interference with 1.024 Mbps ASK modulated have been shown. Frequency synthesizer as a transmitting signal source reveals very short locking time of 26 usec and outstanding phase noise of -115 dBc/Hz at 1 MHz offset from 5.8 GHz center frequency.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.79-85
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• 2004

In this paper, the RF-ID system for ubiquitous tagging applications has been designed, fabricated and analysed. The RF-ID System consists of passive RF-ID Tag and Reader. The passive RF-ID tag consists of rectifier using zero-bias schottky diode which converts RF power into DC power, ID chip, ASK modulator using bipolar transistor and slot loop antenna. We suggest an ASK undulation method using a bipolar transistor to compensate the disadvantage of the conventional PIN diode, which needs large current Also, the slot loop antenna with wider bandwidth than that of the conventional patch antenna is suggested The RF-ID reader consist of patch array antenna, Tx/Rx part and ASK demodulator. We have designed the RF-ID System using EM and circuit simulation tools. According to the measured results, The power level of modulation signal at 1 m from passive RF-ID Tag is -46.76 dBm and frequency of it is 57.2 KHz. The transmitting power of RF-ID reader was 500 mW

• Journal of Korean Library and Information Science Society
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• v.40 no.1
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• pp.133-155
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• 2009

To deal with a new environment of information technologies in the 21 Century, many libraries around the world have made great efforts to develop online knowledge-information services. In Korea, the National Library initiated an online knowledge-information services, in 2008. Through case studies and practical tests of online knowledge-information services, this article discusses plans for developing . The article explores definitions and types of online knowledge-information services, and analyzes online knowledge-information services in Denmark, Sweden, Finland, and Korea. Futhermore, practical reviews on the four services are conducted through 'question-answer' tests. As a result, the article discusses present and future tasks for improving .