• 한국자기학회지
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• 제25권1호
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• pp.22-26
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• 2015

이 논문에서 Ni-Zn 페라이트 코어와 칩캐패시터를 이용하여 제작한 주기적인 연결구조에서 발생하는 자기유도파(magneto-inductive wave)에 대한 실험적 결과를 보고 한다. 주기적 연결구조는 동일한 공진주파수를 가진 LC공진기(LC resonator)로 되었으며, 개별 공진기는 도선과 칩캐패시터로 구성되었다. 인접하는 공진기들은 패라이트코어를 통해서 자기적으로 결합되었다. 제작된 주기적 구조의 특성을 검토하기 위해서 네트워크 아날라이저를 이용한 S-파라미터를 분석하여 신호전송특성을 평가하였다. 5개의 LC공진기를 1차원적으로 연결하여 제작한 주기구조의 신호전송 중심주파수는 32 MHz~38 MHz였으며, 이는 인가자계의 크기에 의해서 조정할 수 있었다.

• Journal of electromagnetic engineering and science
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• 제9권1호
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• pp.25-31
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• 2009

This paper describes CMOS VCO circuit design procedures and techniques for multi-band/multi-standard RF transceivers. The proposed techniques enable a 4 GHz CMOS VCO to satisfy all requirements for Quad-band GSMIEDGE and WCDMA standards by achieving a good trade-off among important specifications, phase noise, power consumption, modulation performance, and chip area efficiency. To meet the very stringent GSM T/Rx phase noise and wide frequency range specifications, the VCO utilizes bond-wire inductors with high-quality factor, an 8-bit coarse tune capbank for low VCO gain(30$\sim$50 MHz/V) and an on-chip $2^{nd}$ harmonic noise filter. The proposed VCO is implemented in $0.13{\mu}m$ CMOS technology. The measured tuning range is about 34 %(3.17 to 4.49 GHz). The VCO exhibits a phase noise of -123 dBc/Hz at 400 kHz offset and -145 dBc/Hz at 3 MHz offset from a 900 MHz carrier after LO chain. The calculated figure of merit(FOM) is -183.5 dBc/Hz at 3 MHz offset. This fully integrated VCO occupies $0.45{\times}0.9\;mm^2$.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권6호
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• pp.712-717
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• 2014

The performance of npn SiGe HBT on thin film SOI is investigated at 32 nm technology node by applying body bias. An n-well is created underneath thin BOX to isolate the body biased SOI HBT from SOI CMOS. The results show that the HBT voltage gain and power gain can be programmed by applying body bias to the n-well. This HBT can be used in variable gain amplifiers that are widely used in the receiver chain of RF systems. The HBT is compatible with 32 nm FDSOI technology having 10 nm film thickness and 30 nm BOX thickness. As the breakdown voltage increases by applying the body bias, the SOI HBT with 3 V $V_{CE}$ has very high $f_tBV_{CEO}$ product (839 GHzV). The self heating performance of the proposed SOI HBT is studied. The high voltage gain and power gain (60 dB) of this HBT will be useful in designing analog/RF systems which cannot be achieved using 32 nm SOI CMOS (usually voltage gain is in the range of 10-20 dB).

• ETRI Journal
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• 제30권4호
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• pp.526-534
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• 2008

This paper presents a fully integrated 0.13 ${\mu}m$ CMOS MB-OFDM UWB transmitter chain (mode 1). The proposed transmitter consists of a low-pass filter, a variable gain amplifier, a voltage-to-current converter, an I/Q up-mixer, a differential-to-single-ended converter, a driver amplifier, and a transmit/receive (T/R) switch. The proposed T/R switch shows an insertion loss of less than 1.5 dB and a Tx/Rx port isolation of more than 27 dB over a 3 GHz to 5 GHz frequency range. All RF/analog circuits have been designed to achieve high linearity and wide bandwidth. The proposed transmitter is implemented using IBM 0.13 ${\mu}m$ CMOS technology. The fabricated transmitter shows a -3 dB bandwidth of 550 MHz at each sub-band center frequency with gain flatness less than 1.5 dB. It also shows a power gain of 0.5 dB, a maximum output power level of 0 dBm, and output IP3 of +9.3 dBm. It consumes a total of 54 mA from a 1.5 V supply.

• 대한의생명과학회지
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• 제29권3호
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• pp.190-200
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• 2023

Skeletal muscle, essential for metabolism, thermoregulation, and immunity, undergoes myogenic differentiation that results in myotube formation. Trans-anethole (TA), the major constituent in essential oil produced by anise, star anise, and fennel, whose function in skeletal muscle has not yet been elucidated. Therefore, we investigated whether TA influenced muscle differentiation in mouse C2C12 myoblasts. Cells were induced to differentiate using a differentiation medium with or without TA (50 or 200 mg/mL) daily for 5 days. We measured myotube length and diameter after differentiation days 1, 3, and 5 and analyzed the expression of myogenic markers (myoblast determination protein 1, myogenin, myocyte enhancer factor 2, muscle creatine kinase, and myosin heavy chain) and atrophy-related genes (atrogin-1 and muscle ring finger-1 [MuRF-1]) using quantitative real-time PCR. Additionally, we observed the expression of total protein kinase B (Akt) and phosphorylated Akt (p-Akt) using western blotting. Our data showed that TA significantly induced the formation of smaller and thinner myotubes and reduced the myogenic factor expression. Furthermore, the atrogin-1 and MuRF-1 expression markedly increased by TA. Consistent with these findings, TA significantly decreased the expression of total Akt and p-Akt. Taken together, these results indicate that TA inhibits myogenic differentiation of C2C12 cells via reduction of both total Akt and p-Akt. Our findings may provide valuable insights into the impact of PAA on individuals at risk of muscle atrophy.

• 한국산업정보학회논문지
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• 제14권2호
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• pp.23-31
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• 2009

미국에서 발생한 9.11 테러 이후 물류보안(Supply Chain Security)에 대한 패러다임이 발생하였으며, 국외의 관련 기업과 기관들은 물류보안을 위하여 다양한 연구들을 진행하였다. 하지만 국내의 경우 물류보안이라는 용어 자체가 생소할 뿐만 아니라 보안에 관한 패러다임이 물류부분까지 확산되지가 않아서 관련 연구가 부족한 실정이었으나, 최근에 물류보안 기술 중의 하나로서 RFID 기반 컨테이너 화물 안전수송 장비인 ConTracer(Container Tracer)를 개발하는 등 관련 연구가 활성화되기 시작하였다. 현재 개발되고 있는 컨테이너 화물 안전수송 장비들의 주요 이슈는 높은 인식률과 충분한 인식거리가 확보되는 것이며, 본 연구에서는 이러한 목적을 달성하기 위하여 다구찌 방법론을 활용하여 ConTracer(433MHz 타입, 2.4GHz 타입)의 인식률 향상을 위한 다양한 실험을 하였다. 실험결과 433MHz 주파수에서는 리더기의 방향을 전방우측으로 향하는 것이 다소 유리하고, 2.4GHz 주파수에서는 크게 영향을 미치지는 못하는 것으로 나타났으며, 안테나의 위치는 예상했던 대로 두 주파수 모두 외부에 설치하는 것이 인식률 향상에 유리한 것으로 분석되었다.

• 한국운동역학회지
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• 제25권4호
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• pp.383-391
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• 2015

Objective : The purpose of this study was to investigate the effects of dynamic squats with slope-whole body vibration (WBV) on the trunk and lower limb in muscle activities. Method : 9 healthy women (age: $21.1{\pm}0.6years$, height: $160.5{\pm}1.4cm$, body weight: $50.5{\pm}2.4kg$) were recruited for this study. Muscle activities in the trunk and lower limb muscles, including biceps femoris (BF), rectus femoris (RF), rectus abdominum (RA), gastrocnemius (GCM), iliocostalis lumborum (IL) and tibialis anterior (TA), were recorded using an EMG measurement system. The test was performed by conducting dynamic squats with slope-WBV using frequency (10Hz, 50Hz), amplitude (0.5mm), and degree ($0^{\circ}$, $5^{\circ}$). Experimental method consisted of 2-pre-sessions and 1-test-session for 20 seconds. Results : The results showed that the muscle activities of the trunk and low limb muscles increased significantly with the $5^{\circ}$ slope and lower frequency (10Hz) except for in the TA. From this result, we confirmed that the slope and WBV could efficiently affect stimulation, enhancing muscle activities by facilitating neural control trail and muscle chain tightness. Conclusion : Utilizing the slope-WBV device while squatting could give positive effects on muscle activation in the trunk and lower limb muscles and provide neural stimulation, enhancing muscle chain of control subsystem through TVR (tonic vibration reflex).

• 한국경영정보학회:학술대회논문집
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• 한국경영정보학회 2007년도 International Conference
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• pp.951-958
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• 2007

Radio Frequency Identification (RFID) is a technology for automated identification of objects and people. RFID may be viewed as a means of explicitly labeling objects to facilitate their "perception" by computing devices. RFlD systems have been gaining more popularity in areas especially in supply chain management and automated identification systems. However, there are many existing and potential problems in the RFlD systems which could threat the technology s future. To successfully adopt RFID technology in various applications. we need to develop the solutions to protect the RFID system s data information. This study investigates important issues related to privacy and security of RF1D based on the recent literature and suggests solutions to cope with the problem.

• IEIE Transactions on Smart Processing and Computing
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• 제3권4호
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• pp.240-245
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• 2014

How well the self-interference cancellation (SIC) technique performs is a primary issue in realizing an in-band full-duplex (FD) wireless communication system. One factor affecting its performance is channel estimation error on the self-interference channel. We propose a new analog SIC scheme which is robust to channel estimation error. It uses phase rotators in the radio frequency (RF) chain. We also derive closed-form equations for the residual self-interference of the proposed and the conventional schemes. The analytical and numerical results show that the residual self-interference under the proposed SIC scheme is less than that using the conventional scheme, even though channel estimation error is present.

• 전자공학회논문지CI
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• 제46권3호
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• pp.34-41
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• 2009

본 논문은 반수동형 센서 태그의 센서 데이터를 효율적으로 읽기에 대한 주제를 고찰한다. 콜드 체인 관리 시스템에서는 데이터의 손실이 없이 센서 데이터가 완전하게 읽히고 빠른 처리 시간 안에 센서 태그 데이터를 읽는 것을 요구한다. 하지만, 센서 태그 데이터를 읽을 때 전파방해나 장애물과 같은 RF 환경에 의한 간섭을 받게 된다. 본 연구에서는 이러한 원인이 센서데이터의 손실을 발생시키고 데이터 손실이 발생하였을 때 센서 데이터를 읽는데 더 많은 시간이 걸리는 것을 알아냈다. 이러한 문제점을 해결하기 위하여, 우리는 센서 데이터의 효율적인 읽기를 보장해주는 트랜잭션 처리 메커니즘을 제안한다. 이를 위해, 우리는 읽기 트랜잭션 실행을 위해 동적 패킷 크기 기법과 데이터 복구 기법을 설명한다. 이러한 기법은 대용량의 데이터를 위한 처리시간 단축뿐만 아니라 읽기 연산의 신뢰성 또한 개선시킨다. 본 논문에서 데이터의 손실도 없고 많은 시간 소요도 없는 센서 데이터의 효율적인 읽기 수행의 개선에 기여함을 확인하였다.