• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.71-74
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• 2007

Substitution of the stacked antenna for the normally pressed antenna in the mobile phone was tried for the purpose of decreasing its size. However, reduced size resulted in the difficulties obtaining the targeted characteristics with the bandwidth over 70MHz. The cross-section of the vias in the low temperature co-firing ceramics process was studied to find out effects on the bandwidth characteristics. Circular and rectangular cross-section of the via beneath different types of antenna patterns were simulated. Better bandwidth characteristics were acquired for the larger diameter of the circular section and for the rectangular section as the cross-section area increased. From the viewpoint of the shape of the cross-section, rectangular area showed better characteristics than the circular area with the same longest length in the cross-section.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 추계학술대회 논문집
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• pp.101-104
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• 2000

Milli-structure components are classified as component group whose size is between macro and micro scale. that is, about less than 20mm and larger than 1mm. The forming of these components has a typical phenomenon of bulk deformation with thin sheets because of the forming size. In order to conventional metal forming, where numerical process simulation is already idly applied, the micro-forming process is characterized by some scale effects which have to be considered in an advanced process simulation. milli-structure rectangular cup drawing is analyzed and designed using the finite element method and experiment. The result of the finite element analysis is confirmed by a series of experiment.

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 2006년도 춘계학술발표대회 논문집
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• pp.108-111
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• 2006

Recently, mobile information devices, such as cellular phone, PDA(Personal Digital Assistant, PDA) are getting smaller and thinner. Accordingly, ultra precision welding technology is required to manufacture the high performance system for use in the telecommunication industry. In this study, we propose the laser micro welding process. Using ytterbium fiber laser, a wide range of experiments have been carried out for the gold wire-to-gold thin film welding.

• 정보처리학회논문지D
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• 제8D권3호
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• pp.265-272
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• 2001

이동단말(mobile phone, PDA, smart phone, notebook PC 등)에서 WAP을 구현하고자 할 경우, 이동단말마다 운영체제가 상이하므로 프로그램 흐름의 제어, 인터럽트, IPC등 운영체제 특성을 반영한 별도의 구현이 필요하다. 이로 인하여 개발기간의 단축이 어려움은 물론 개발비용 증가, 개발인원의 투여, 시장 조기 진입의 어려움 등이 존재한다. 본 논문은 WAP을 다중 플렛폼에서 구현하기 위한 기저를 제공하는 추상 커널 계층(Abstract Kernel Layer)의 설계와 구현에 관한 것이다. 이는 REX, Palm, MS-DOS. MS-Window, UNIX 및 Linux를 포함한 각종 운영체제를 지원하는 커널 계층을 설계하여, 기기 종속적인 부분을 최소화되고 일관적인 인터페이스를 지원하여 개발 기간을 단축하고 소프트웨어의 유지보수를 용이하게 하는데 그 목적이 있다. 또한 추상 커널 계층은 mobile phone과 PDA에 탑재하여 그 실용성을 입증하였다.

• 대한임베디드공학회논문지
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• 제12권4호
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• pp.259-266
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• 2017

GPS was developed for military purposes. As a result, it is used as a military important means such as guided weapons and strategy / tactics. However, GPS depends on the communication infrastructure and is affected by interference signals. In this paper, we propose a secure micro - web page - based smart map that can enhance security without relying on communication infrastructure on the battlefield. The proposed system consists of general smartphone, security QR, central server and smart map. Only use the network when downloading the security key and SmartMap before the task starts. During operation, the smartphone transmits and receives data using a secure QR. The security QR inserts the security code to prevent forgery and falsification and confirms whether the data is authentic by checking whether the smart phone is forged or not. As a result of implementation, we solved communication security problem of existing technology by using location based service without relying on communication infrastructure.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.63-63
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• 2008

Environmental monitoring sub-system has been developed using gas sensor module, Bluetooth module and PDA phone. The gas sensor module consists of $NO_2or$ CO gas sensor and signal processing chips. Gas sensor is composed of the micro-heater, sensing electrode and sensing material. Metal oxide nano-material was selectively deposited on a substrate with micro-heater and was integrated to the gas sensor module. The change in resistance of the metal oxide nano-material due to exposure of oxidizing or deoxidizing gases is utilized as the principle of this gas sensor operation mechanism. This variation detected in the gas sensor module was transferred to the PDA phone by way of Bluetooth module.

• 소성∙가공
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• 제20권1호
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• pp.11-16
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• 2011

Recently, according to the rapid development of display, many display applications, such as, cellular phone, navigation, monitor and LCD TV have been changed from CRT type to LCD type. BLU(Back Light Unit) is one of main parts in LCD unit and generally, it consists of a light source, a reflective sheet, a LGP(Light Guide Plate), a diffuser sheet, and two prism sheets. The most important component of BLU is a light guide plate, which diffuses the input light to the TFT-LCD module uniformly. The LGP is usually made by injection molding process, and it has numerous optical micro patterns on the surface. In the present study the micro-patterned stamper which has cylindrical shape was fabricated by using the UV-LiGA process. And the replication characteristics have been compared among three different kinds of injection molding process; general injection molding, injection/compression molding and RHCM(Rapid Heating and Cooling Molding). Average replication ratios of CIM and ICM were 19.1% and 64.6%, respectively. On the other hand, the average replication ratio of RHCM process showed the higher value of 98.4% among these. It show that maintaining the mold surface above $T_g$ could increase the replication ratio of micro patterns substantially.

• 한국전기전자재료학회논문지
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• 제20권9호
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• pp.808-811
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• 2007

Aspheric glass lens have recently been used in camera phone module because they are more effective than spherical ones. In this paper, the grinding condition of the tungsten carbide molding core has been found after applying DOE to the development of the aspheric glass lens for the 3 Megapixel and 2.5x camera-phone module. Also, the ultra precision grinding process was investigated under this condition by experiment. Re-Ir coating was applied on the ground surface of the tungsten carbide molding core. The influence of Re-Ir coating on the form accuracy and surface roughness of molding core was compared and evaluated. The form accuracy and surface roughness of the molding core were improved by application of Re-Ir coating on the surface of the tungsten carbide molding core.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 추계학술대회
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• pp.473-476
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• 2012

에너지는 인간사회가 필요로 하는 가장 중요한 자원중의 하나로서 에너지개발과 이용의 역사는 인류역사의 한 줄기를 이루고 있습니다. 특히 풍력의 환경 친화적인 에너지 개발의 필요성이 대두되면서 대체에너지에 대한 관심이 지속적으로 높아지고 있습니다. 본 논문에서는 스마트폰을 활용하여 초소형 수직축 풍력발전기에서의 에너지 생산량 및 효율을 기상청 기후변화 시스템의 풍속과 블레이드의 폭과 그 재질에 따른 실시간 에너지 생산 효율을 분석하는 시스템을 제시한다.

• 전력전자학회논문지
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• 제9권2호
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• pp.187-193
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• 2004

PDA, 스마트폰, USP 및 전기자동차와 같은 전기적 장치의 전력공급을 위하여 배터리가 직렬로 연결된 다중 셀을 만들어 일반적으로 사용한다. 이 경우 개별 셀 전압의 편차가 발생되면 배터리의 수명과 용량은 낮아지게 된다. 셀에서 전압의 안정화상태를 유지하기 위한 셀 전압을 안정화시키는 효율적인 방범은 없어서는 안 될 중요한 사항이다. 본 논문에서는 휴대형 가전기기에 적용하기 위해 마이크로컨트롤러를 사용한 다중 셀용 밸런싱 회로의 설계에 대하여 제안한다. 밸런싱 시스템은 충전되는 주기 동안 밸런싱 동작을 이행하며 마이크로컨트롤러로서 제어된다. 제안된 방법은 충전기와 레코드를 사용하여 실험을 통해 증명하였다. 실험결과에서 개별 배터리의 용량, 수령, 성능이 향상됨을 보여준다.