• Journal of information and communication convergence engineering
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• 제9권6호
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• pp.695-700
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• 2011

Smartphone has formed a new market and introduced a new environment. They have an operating system like PCs, enabling free installation and removal of application programs. As the number of Smartphone users is increasing, more personal information is also exposed to malicious codes. There are problem of modification and deletion of files, battery consumption, and information leakage due to malicious codes. As the needs of Smartphone antivirus solutions are increasing, the antivirus solutions should be evaluated with quality characteristics. In this paper, we propose an effective evaluation method for functionality and performance of Smartphone antivirus solutions, and the best practices for evaluation.

• 한국수소및신에너지학회논문집
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• 제21권4호
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• pp.321-327
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• 2010

Current rechargeable battery cannot provide high energy density and the operational durations required. But linear engine/generators provide high energy density for portable power applications because fuel is more high density. In this paper, we suggest that basic design of powerpack using linear engine for assisting power output. Efficiency is relatively high because linear engine don't have crank mechanism compared with rotary engine. We made prototype engine and had experiments to know moving characteristic about the Linear Engine. It was possible to operate velocity at 50 Hz at the firing and pressure in cylinder was 16bar.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.35-35
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• 2003

Recent progress in the integration of the ferroelectric random access memories (FRAM) has attracted much interest. Strontium bismuth tantalate(SBT) is one of the most attractive materials for use in nonvolatile-memory applications due to low-voltage operations, low leakage current, and its excellent fatigue-free property. High-density FRAMs operated at a low voltage below 1.5V are applicable to mobile devices operated by battery. SBT films thinner than 0.1 #m can be operated at a low voltage, because the coercive voltage (Vc) decreases as the film thickness is reduced. In addition, the thickness of the SBT film will have to be reduced so it can fit between adjacent storage nodes in a pedestal type capacitor in future FRAMs.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1515_1516
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• 2009

A 440MHz wireless and passive surface acoustic wave (SAW) based micro-sensor was developed for simultaneous measurement of temperature and humidity. The developed sensor is composed of a SAW reflective delay lines structured by an IDT (Inter-Digital Transducer), four reflectors and humidity sensitive film (polyimide). Polyimide was dry-ecthed by RIE (Reactive Ion Etching) to obtain high roughness, which gives the large reaction area resulting in high sensitivity. In wireless testing using a network analyzer, sharp reflection peaks with high S/N ratio, small signal attenuation, and few spurious peaks were observed in the time domain. High sensitivity towards the temperature and humidiy were also observed in the large concentration range. The obtained sensitivity was $16.8^{\circ}/^{\circ}C$ for temperature sensor and $15.8^{\circ}$/%RH for humidity sensor.

• 한국수소및신에너지학회논문집
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• 제22권4호
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• pp.512-519
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• 2011

Current rechargeable battery cannot provide high energy density and the operational durations required. But linear engine/generators provide high energy density for portable power applications because fuel is more high density. In this paper, we suggest that basic design of powerpack using linear engine for assisting power output. Efficiency is relatively high because linear engine don't have crank mechanism compared with rotary engine. We made prototype engine and had experiments to know moving characteristic about the Linear Engine. It was possible to operate velocity at 50 Hz at the firing and pressure in cylinder was 16bar.

• 한국멀티미디어학회논문지
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• 제23권2호
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• pp.227-240
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• 2020

This paper proposes a novel CTC technology, CB-sense. The CB-sense guarantees a dedicated period for the CTC that results in low duty cycle of the receiver device. In addition, it send a lot of information explosively during the dedicated CTC period. Thus, it can achieve high throughput. The CB-sense uses Clear to Send (CTS) packets to transmit information bits to the heterogeneous wireless technologies. The CTS packets block the neighboring node transmissions, so it reduces co-channel interference. In experiment results, CB-sense represents 20 times more throughput than FreeBee and below 5% symbol error rate in the interference environment.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.187-188
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• 1998

A low cost, low power, portable cardiac event recorder as a tether-free biological signal processor was developed. Dual channel ECG signals are sampled at 128Hz in 12 bits resolution. Sampled data are continuously recorded in a circular buffer. If event button is pressed, 2 minutes data before and after the event are recorded in 512 Kbyte SRAM. Total 11 events can be recorded. Data can be transferred to PC through RS-232 protocol. It operates for two months by a half AA size 3.6V Lithium battery. The system size is $55\times55\times13[mm^3]$.

• 한국생산제조학회지
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• 제24권6호
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• pp.619-624
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• 2015

Owing to miniaturization and low-power electronics, mobile, implanted, and wearable devices have become the main trends of electronics during the past decade. There has been much research regarding energy harvesting to achieve battery-free or self-powered devices. The optimal design problems of a double-pendulum kinetic-energy harvester from human motion are studied in this paper. For the given form factor, the weight of the harvester, and the known human excitation, the optimal design problem is solved using a dynamic non-linear double-pendulum model and an electric generator. The average electrical power was selected as the performance index for the given time period. A double-pendulum harvester was proven to be more efficient than a single-pendulum harvester when the appropriate parameters were used.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2009년도 춘계학술발표논문집
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• pp.645-648
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• 2009

본 논문에서는 신재생에너지 활용을 위한 휴대용 하이브리드 태양광 풍력 발전 시스템을 제안한다. 제안하는 태양광 풍력 복합 발전 시스템을 상용전기와 연계하여 사용할 경우를 고려하여 중대형 풍력 발전 시스템용 인버터와는 다른 특성이 요구되는 소형풍력 발전 시스템용 인버터와 독립형으로의 사용을 위해 축전지 충방전 컨트롤러를 개발한다. 20W의 Solar Power, 50W의 Wind Power, 1개의 Radio-recorder, 2개의 DC 7W/9W lamp. 축전지 Controller, 24H/40AH Maintenance-free battery 사양을 갖는 발전 시스템을 제작하고 필드 테스트를 통하여 성능을 검증한다.

• 한국전자통신학회논문지
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• 제8권10호
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• pp.1499-1504
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• 2013

급격한 원유가격 상승과 환경 친화적 차량에 대한 수요가 증가하면서 전기자동차에 대한 연구개발이 활발히 진행되고 있으며, 특히 근거리 전기자동차(NEV)는 양산 가능성이 매우 높은 무공해 차량으로 관련 기술에 대한 개발이 시급히 요구되는 시점이다. 본 논문에서 연구하고자 하는 중대형 2차전지 On-Board 충전기는 우주항공 및 일반 산업 분야에서도 충분히 응용가능한 요소 기술이고, Off-Board 스탠드형 충전기는 향후 활성화될 충전 인프라 구축 사업에 활용할 수 있을 것으로 예상된다.