• Journal of IKEEE
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• v.14 no.3
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• pp.250-255
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• 2010

The interleaved power management IC(PMIC) with DTMOS(Dynamic Threshold voltage MOSFET) switching device is proposed in this paper. The buck-boost converter used to provide the high output voltage and low output voltage for portable applications. Also we used the PWM(Pulse Width Modulation) control method for high power efficiency at high current level. DTMOS with low on-resistance is designed to decrease conduction loss. The interleaved PMIC to reduce output ripple. And step-down DC-DC converter in stand-by mode below 1mA is designed with LDO in order to achive high efficiency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.493-496
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• 2007

As the ubiquitous society period has set in recently, which resulted from both mass distribution of portable devices such as PDA, PMP, Smart Phones, the demand for more optional features of system and multimedia functions has been increasing. In compliance with thoses needs, the amount of information increased in a system and greater power capacities are needed more than ever. Therefore, in portable device which uses battery as a limited source of power, the power management has become a key factor in the system. This paper concentrates on the Power management solution for Smart device for the prevention of missing child. And ARM9 Core was used as CPU and Windows CE 5.0 was ported to the smart device.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1585-1591
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• 2010

DMFC uses oxygen by reactants. Therefore, cathode electrode must contact with outside air. However, when used in mobile devices, the user's body by blocking the air intake on the oxygen supply DMFC con not. DMFC to supply air to the cooling fan is used. However, by using cooling fan, air inlet to the pressure loss and changes will occurs, the output will be worse. In this paper, we designed air supplying system using piezo actuators. We DMFC evaluation system was implemented, verified the performance of air supplying system. And the operation was connected to an MP3 player.

• The Journal of the Korea Contents Association
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• v.8 no.8
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• pp.74-80
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• 2008

Various mobile contents have been developed with the spread of cellular phones. Above all things, nowadays, an idle application services are developed through competition in mobile phone manufacturers and mobile communication companies. In this paper, we propose that the idle application with text message service is easy to receive and edit. It is complement to function of SMS in use and can be effective information managing method, for example, it arrays messages and uses diary feature to set permissions when it send and receive standardized text message. We expect that proposed service will be adopted without additional cost in wireless units.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2006.05a
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• pp.291-305
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• 2006

본 연구는 국내 모바일 컨텐츠 비즈니스에서 향후 킬러 애플리케이션으로 예상되고 있는 위치기반서비스(이하 LBS)의 적용 가능성 분석을 통한 발전 방향에 관한 연구이다. 국내 모바일 컨텐츠 산업은 그 성장성, 국내 타 산업 환경과의 적합성, 향후 다양한 분야로의 응용을 통한 수익 창출의 측면에서 매우 중요한 의미를 가지고 있다. 그러나 지난 수년간 이미 내수 가입자의 시장이 포화되었고 또한 사업방향이 단순히 게임 컨텐츠에 집중됨으로써 발전가능성에 적합하지 않는 취약한 구조적 문제를 갖고 있다. 향후 모바일 컨텐츠 비즈니스가 미래 성장 동력으로 변모하기 위해서는 사용자와 모바일 기기 관점에서 현재 성장을 억제하고 있는 시장의 환경적 요인 분석과 공급주체 측면에서의 연구를 통해 새로운 발전 모델을 구축하는 것이 시급하다. 따라서 본 연구는 국내 모바일 컨텐츠 비즈니스가 가진 현재의 한계점을 주목하여 그 한계를 뛰어넘기 위한 방법으로 LBS를 제안하고자 한다. 우선 본 연구제안의 근거로서 기존 모바일 관련 연구들을 바탕으로 1차 검증을 거친 후, LBS 컨텐츠와 관련한 연구 모델을 설정하고 설문조사를 수행하여 실증적으로 분석하였다. 본 연구에서 얻어진 데이터 분석을 통해 향후 비즈니스 모델의 핵심인 기능 컨버젼스 휴대폰과 LBS 활용 서비스를 중심으로 한 컨텐츠 컨버젼스를 효과적으로 융합한 모바일 컨텐츠 비즈니스의 향후 성장가능성에 대해 제시하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.6
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• pp.814-820
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• 2009

The arrangement of the general 12-button cellular phone keypad is unified with one or two kind. In general, the several alphabets are arranged in one key. When inputting an English, countries which do not speak English use multi-tap method. We can input next alphabet by pressing key repeatedly. We address the problem of finding multi-tap-based keypad designs which minimize the number of key presses for various case. Genetic algorithms is proposed method for optimal keypad designs. We are to maintain the number of keys, which is ranged from 8 to 12. We also show experimental using non-alphabetically-constrained and alphabetically-constrained arrangement, respectively. Finally, we give improved keypad designs.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.675-682
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• 2013

This paper tries to solve the problems which previous methods have the model using smart card for protecting digital contents. This study provides a contents distribution model to protect the rights of author, distributor, and user as well as user's information by using technologies such as cryptography, DRM(Digital Right Management), access control, etc. The proposed system is evaluated as the most safety model compared with previous methods because it not only solves the problems which the previous methods have, but also protects four type of risks such as use of contents which other mobile devices download, the attack on the key to decode the message, the attack on leaking the contents, and the internal attack such as an illegal reproduction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1343-1354
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• 2007

Secondary batteries become more important in our lives as the use of portable electric devices, such as camera, cellular phone, laptop, etc. Especially, because of their high energy densities and high voltage, lithium-ion batteries are being used in many systems. For the optimum design of such systems which include lithium-ion batteries, virtual prototype is required generally. However, since the complex chemical and physical processes are involved, the behavior of battery becomes harder to be predicted compared with that of electric and mechanic devices. This paper, proposes a new static model of lithium secondary battery, which accounts for nonlinear equilibrium potentials, rate and temperature dependencies, thermal effects, lifetime characteristic. The results of the simulation of the model are analysed and compared with experimental data to inspect their validity.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.119-122
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• 2015

기타를 처음 접할 때 겪는 어려움은 크게 운지법과 곡에 대한 이해다. 연주자마다 곡의 연주 방법이 상이하기 때문에 한 곡에 대해서도 다양한 타브 악보가 존재한다. 이 논문은 타브 악보를 인식하여 연주를 수행하는 휴대 가능한 시스템 설계를 제안한다. 기 연구된 악보 인식은 5선 기반의 악보를 대상으로 하였으며 수평 히스토그램을 사용하여 5선을 제거 한 뒤 나타나는 기호들을 인식했다. 본 논문에서는 6선인 타브 악보 인식 및 연주 시스템을 휴대 기기에서도 사용 가능하게 설계하여 많은 연산 양이 요구되는 선 제거 과정을 거치지 않는다. 템플릿 매칭 기법으로 전체 악보에서 타브 악보의 영역을 탐색하고, 탐지된 영역 안에서 선의 시작점을 탐색한다. 선의 시작부터 끝까지 가상 블록을 사용하여 선에 존재하는 공백을 탐지하고, 공백의 분할을 이용해 프렛을 분할하며, 프렛 인식은 프로토타입 기반 분류기를 이용하여 97.0%의 인식률을 보였다.

• Resources Recycling
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• v.22 no.4
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• pp.12-21
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• 2013

Waste electrical and electronic equipment(WEEE or E-waste) is one of the fastest growing waste stream in Korea. The proper management of such equipment has become of major concern for solid waste professionals because of the large growth of the waste stream and the presence of a myriad of toxic materials in it. In this paper, in order to evaluate the economical value of the recycling metallic materials from the E-waste, big size electrical home appliances, small size electrical home appliances, end of life hand phone and PCB(printed circuit board) were reviewed.