• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1565_1566
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• 2009

This paper presents the design and analysis of RF Front End for Wireless Heartbeat measurement System. In this work LNA, an inductor connected at the gate of the cascode transistor and capacitive cross-coupling are strategically combined to reduce the noise and the nonlinearity influences of the cascode transistors in a differential LNA. The Mixer is implemented by using the Gilbert-type configuration, cross pmos injection technique and the resonating technique for the tail capacitance. The resulting LNA achieves 1.26dB NF, better than 1.88dB NF Typical. Also Mixer resulting achieves 9.8dB at 100KHz.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.427-430
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• 2006

유비쿼터스 시대의 도래와 유비쿼터스 환경이 가장 먼저 구축되고 있는 홈네트워크 환경에 대한 관심이 높아 지고 있다. 이종 네트워크와 디바이스들이 서로 연동을 이루어 사용자에게 서비스를 제공하고 있는 이러한 홈네트워크 환경 구축에 있어서 그 중요성에도 불구하고 보안적인 요소가 배제되어 있는 경우가 많다. 이에 따라 본 논문에서는 홈네트워크 환경에서 요구되는 보안사항을 분석하고 사용자 인증을 위해 생체 정도가 담긴 스마트 카드를 이용해 인증서 기반 EAP-TLS를 사용하는 구조를 제안한다.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.75-79
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• 2001

This paper presents a novel version of an active voltage clamped ZVS-PWM high frequency inverter using IGBTs for electromagnetic induction eddy current-based rolling drum heating in new generation copy and printing machines in consumer business use. The operating principle of this inverter circuit and unique features are described herein. Its constant frequency duty cycle (asymmetrical PWM) controlled voltage source quasi-resonant soft switching high frequency inverter employing IGBTs is proposed, which is capable of achieving stable and efficient zero voltage soft switching commutation over a widely specified power regulation range from full power to low power. The operating performances in a steady state of this inverter is discussed and evaluated on basis of simulation and experimental results as an induction heated roller in new generation copy machine.

• Journal of Information Display
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• v.7 no.4
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• pp.5-8
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• 2006

The optical structures and rigorous electromagnetic modeling of OLEDs will be discussed of first and then their applications in analyses and designs of various advanced OLED structures, e.g. microcavity OLEDs, tandem OLEDs and top-emitting OLEDs etc., will be reported.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1809-1812
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• 2006

In this paper, the thermally evaporated molybdenum oxide $(MoO_x)$ is investigated as the effective hole-injection material for organic lightemitting devices (OLEDs). The use of $MoO_x$ significantly lowers the operating voltage of OLEDs, insensitive to the anode materials used.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.229-232
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• 2006

General discussions of the optical structures and rigorous electromagnetic modeling of OLEDs will be first given, and then their applications in analyses and designs of various advanced OLED structures, e.g.microcavity OLEDs, tandem OLEDs and top-emitting OLEDs etc., will be reported.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.440-442
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• 2002

The electrical characteristics of biologically active points (BAPs) compared with those of the surrounding human skins are studied. And we confirm that BAPs have lower resistance and higher capacitance than the surrounding skins do. We also find that BAPs have higher characteristic frequency than surrounding skins and the impedance spectra of BAPs sometimes have two semicircles on the complex impedance plane. We propose the skin impedance model that is proper to the BAPs and this circuit describes our experimental results sufficiently well.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.754-757
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• 2006

네트워크 자가 형성 기법이 유비쿼터스 컴퓨팅을 위한 필수 요소 기술로 자리매김하고 있다. 그러나 아직까지 이를 통해서 안전하고 효율적으로 네트워크를 구성하는 기법에 대한 요구사항 도출 및 연구가 취약하다. 따라서 본 논문에서는 현재의 취약점을 기반으로 유비쿼터스 네트워크에 적합한 안전한 네트워크 자가 형성을 위한 요구사항을 도출하고 그 기법에 대해서 방향을 제안하고자 한다.

• Carbon letters
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• v.13 no.1
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• pp.23-28
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• 2012

Graphene is an attractive material for device applications, but device characteristics are very unstable because the graphene is very sensitive to environmental factors such as charges nearby the graphene, metal contacts, defects, contaminants and other adsorbates. Since the interactions between graphene and environmental factors affect the electrical characteristics of graphene devices, the interpretation of electrical characteristics as simple as current-voltage curves is non-trivial, despite the common practice of using well known electrical characterization methods that have been used in silicon MOSFET. This paper addresses major obstacles in the electrical characterization of graphene devices and offers countermeasures to improve the accuracy of electrical characterization methods.

• Journal of Power Electronics
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• v.12 no.6
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• pp.954-959
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• 2012

A hybrid switch that uses a microelectromechanical system (MEMS) switch as a gate driver of a MOSFET is applied to an energy harvesting system. The power management circuit adopting the hybrid switch provides ultralow leakage, self-referencing, and high current handling capability. Measurements show that solar energy harvester circuit utilizing the MEMS-MOSFET hybrid switch accumulates energy and charges a battery or drive a resistive load without any constant power supply and reference voltage. The leakage current during energy accumulation is less than 10 pA. The power management circuit adopting the proposed hybrid switch is believed to be an ideal solution to self-powered wireless sensor nodes in smart grid systems.