• Journal of the Korea Society of Computer and Information
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• v.15 no.2
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• pp.91-98
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• 2010

In order to control moving facilities on a remote place effectively, it are required to acquire a environment informations such as images where the moving facilities are placed. However, since there is no tools to acquire such informations to the central control system based on the non-networked sensor environments, it is difficult to control the moving facilities remotely. Therefore, we design and implement the Zigbee based image transmission system and communication protocol to control the moving target remotely. The wireless control utilizing the Zigbee protocol is that electrically consumption is more small than the Bluetooth and reliability of data transmission is better. The implemented Zigbee based control systems and communication protocol have the normal and replay function for a realtime control of the moving target under the server PC and the mobile FDA with the WiFi protocol. The functional operability and performance are analyzed by a designed prototype under the wireless home network environment.

• Journal of The Korean Association of Information Education
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• v.9 no.3
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• pp.511-522
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• 2005

The rapid development of information & communication technology has changed the paradigm of education. Recently the area of education is introducing u-Learning, in which learning is possible at any time and in any place through personal information devices such as PDA, tablet PC and mobile phone terminals. Taking advantage of the mobility and individuality of personal information devices, u-Learning can provide learning customized to the characteristics of individual learners without the limitations of time and space and can be effective in situational learning and experiential learning. In order to identify the uses of PDA in teaching.learning and to develop a basic teachinglearning model using PDA, the present study applied PDA directly to classes and examined the effects. According to the result, most students were satisfied with classes utilizing PDA but problems were also found in connection, insufficient contents for PDA, the quality of screen, etc.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.211-215
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• 2015

It comes into the spotlight as the new Blue Ocean in which the connected car industry in which the car and mobile communication technology is convergence. All sorts of infortainments services connecting with the portable electronic device(Smart phone, tablet PC, and MP3 player) and car are rapidly grown. The Connected car emphasizes the vehicle connectivity with the concept that the car has communication with the around on a real time basis and it provides the safety and expedience to the operator and using the thing of Internet (IoT) in the car and supports the application, presently, the entertainment service including the real-time Navigation, parking assistant function, not only the remote vehicle control and management service but also Email, multimedia streaming service, SNS and with the platform. Intelligent vehicle network is studied as the kind according to MANET(Mobile Ad Hoc Network) for the safety operation of the cars of the road and improving the efficiency of the driving. The intelligent vehicle network is comprised for the driving information offering changing rapidly of the communication(V2V: Vehicle to Vehicle) between the car and the car, communication(V2I : Vehicle to Infrastructure) between the infrastructure and the car, and V2X (Vehicle to Nomadic).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.9
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• pp.918-926
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• 1992

In this paper, ferrite-core loop antenna for portable radio receiver is designed and its characteristics are analyzed. Antenna is fabricated by inserting the ferrite core inside the planar conductor loop$(10{\times}6{\times}15mm^3)$. Bandwidth and Q factor of fabricated antenna measure 0.55 MHz and 280, respectively. These results show remarkable enhancement compared to the conventional loop antenna having the same physical dimension(BW=1.9MHz, Q=8.14). Experimental results show that the relative gain of the fabricated antenna is about 11 dB higher than that of the conventional antenna.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.11
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• pp.971-978
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• 2016

Recent trends in miniaturization and lightness in portable electronics parts have driven developments in subminiature screws. This study aims to investigate the thread rolling process of a subminiature screw with an outer diameter and pitch of 1.0 and 0.25 mm, respectively. Finite element (FE) analyses were performed for the thread rolling process of symmetric and asymmetric screw threads. Through FE analyses, various process parameters, such as the horizontal and vertical die gap and the rolling stroke, were investigated in terms of the forming accuracy. The material flow characteristics in the thread rolling process of the symmetric and asymmetric screws were also discussed, and the relevant process parameters were determined accordingly. These simulation results were then reflected on real thread rolling processes, from which the symmetric and asymmetric screws could be formed successfully with allowable dimensional accuracy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.10
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• pp.579-584
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• 2014

In this paper, we propose beamsapce MIMO(mulitple input multiple output) system using patch ESPAR(Electronically Steerable Parasitic Array Radiator) antenna. When using conventional monopole ESPAR antenna, we have advantages cost of hardware and power consumption of RF cirsuit because of single RF chian. But it is difficult to apply to small portable mobile device. Therefore we design patch ESPAR antenna in order to reducing volume and analyze performance of BS MIMO system that is able to MIMO communication with single RF chain. In This paper, we confirm beam pattern of designed patch ESPAR antenna is steered as ${\pm}15^{\circ}$ elevation angle. Furthermore, we design BS MIMO system using this ESPAR antenna and confirm BER performance of this system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.2213-2218
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• 2013

Smart devices such as smart phone, smart TV, tablet, game consoles embrace all categories of Intelligent Communication Device, which enables intelligent applications to be developed, by up loading Context-aware Computing technology that recognizes and reacts nearby diverse phenomena and composing these information, as well as their basic functions. This paper, after saving pre-registered students' movement course and business places harmful to them into students safety network service system, by using location-based service and searching students' movement, considering the degree of breaking away from their regular course, the access to and their stay in crime-crone area, provides the comparative analysis of the system and suggests the ways for safe students guidance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.116-116
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• 2007

21 세기에 접어들면서 인터넷을 통한 정보 통신의 발달과 개인 휴대용 이동 통신기기의 활발한 보급에 따라 휴대형 전자기기들의 소형화와 고성능화로 나아가고 있다. 이러한 전자기기에 사용될 IC의 내장 메모리 또한 집적화 및 고속화, 저 전력화가 이루어져야 한다. 이러한 전자기기들에 필수적인 압전 세라믹스 부품 중 압전 부저 및 기타 음향 부품등을 각종 전자기기와 무선 전화기에 채택함으로써 압전 부품에 대한 수요와 생산이 계속 증가할 것으로 전망된다. 이처럼 압전 세라믹스를 이용한 그 응용 범위는 대단히 방대하며, 현재 모든 압전 부품들은 PZT 계열 재료로 만들어지고 있고, 차후 모두 비납계열 재료로 대체될 것이 확실시된다. Pb의 환경오염은 이미 오래전부터 큰 문제점으로 인식되고 있었으며 그 일례로 미국의 캘리포니아 주에서는 1986년부터 약 800종의 유해물질, 그 중에서도 Pb 사용을 300ppm 이하로 규제하는 Proposition 65를 제정하여 실행하고 있다. 그리고 2003년 2월에 EU (European Union) 에서 발표한 전자산업에 관한 규제 사항중 하나인 위험물질 사용에 관한 지칭 (Restriction of Hazardous Substance, RoHS) 에 의하면, 2006 년 7월부터 전기 전자 제품에 있어서 위험 물질인 Pb을 포함한 중금속 물질(카드늄, 수은, 6가 크롬, 브롬계 난연재)의 사용을 금지한다고 발표하였다. 비록 전자세라믹 부품에 함유된 Pb는 예외 사항으로 두었지만 대체 가능한 물질이 개발되면 전자세라믹 부품에서도 Pb의 사용을 금지한다고 규정하였다. 더욱이 일본은 2005 년부터 Pb 사용을 금지시켰다. 이와 같이 Pb가 환경에 미치는 영향 때문에 비납계 강유전 물질 및 압전 세라믹스 재료에 대한 연구가 전 세계적으로 활발히 진행되고 있다. 본 연구에서는 비납계 강유전체의 patterning을 위해서, NKN 박막을 고밀도 플라즈마원인 ICP를 이용하여 식각 mechanism을 연구하고, 식각변수에 따른 식각 공정을 최적화에 대하여 연구하였다. 가스 혼합비에 따라 식각 할때 700 W의 RF 전력과 - 150 V의 직류 바이어스 전압을 인가하였고, 공정 압력은 2 Pa, 기판 온도는 $23^{\circ}C$로 고정하였다. 식각 속도는 Tencor사의 Alpha-step 500을 이용하여 측정되었으며 식각 시 NKN 박막 표면과 라디칼과의 화학적인 반응을 분석하고 식각 메커니즘을 규명하기 위하여 XPS(x-ray photoelectron spectroscopy)를 사용하였다.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2003.04a
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• pp.7-7
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• 2003

90년대 중반부터 이동통신제품과 인터넷의 대중화에 의한 노트북 PC등 휴대용 멀티미디어제품의 수요 급증은 전자 제품의 소형화 및 복합화를 유도하였으며, 이러한 제품의 추세에 대응하기 위하여 세라믹 부품은 벌크 단품에서 적층형으로 급속하게 바뀌고 있다. 이러한 정보기기의 좀 더 낳은 생산성과 효율을 얻기 위해 소형화, 경량화 및 고기능화의 요구에 대응되는 공정으로서 부품의 표면실장기술이 80년대에 실용화되었고, 이에 따른 칩 부품의 수요도 급격히 증가하고 있다. 대표적인 칩부품중의 하나인 MLCC(Multi Layer Ceramic Capacotor)는 전자제품의 소형경량화 및 대량생산과 더불어 필수적이 수소동자로써 지금까지 그 성장세는 휴대폰과 컴퓨터생산의 빠른 증가에 EK라 매년 약 15% 정도로 증가하고 있으며, 앞으로 그 수요는 더욱더 등가 할 것이다. EH한 고용량 영역까지 용량대를 확장함으로써, 탄탈 및 알루미늄 전해콘덴서의 영역까지도 확대 형성될 것으로 예상되고 있다. 본 강연에서는 MLCC의 제조기술 동향과 시장에 대한 전망에 대해 소개함으로써, 하루가 다르게 발전하고 있는 전자산업의 고용량화, 초소형화, 특수품, 복합화 등의 적층부품 전반의 현황 및 발전방향 파악하는데 조금이라도 도움이 되고자 한다.

• Journal of the Korea Convergence Society
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• v.11 no.2
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• pp.147-154
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• 2020

This study is about the development of ICT-based wearable devices for vision recovery that can cause functional myopia improvement through accommodation training. Vision Training Device(OTUS) is a head mount type wearable device, which naturally stimulates the contraction and relaxation of the ciliary muscles of eye. Users can conduct customized vision training based on personal vision information stored through the device. In the experiment, the effects of improvement of the symptoms by the accommodation training were compared and analysed for the two groups (16 comparative group and 16 accommodation training group) after causing functional myopia. The result showed the functional myopia improved average 0.44D±0.35 (p<0.05) at the accommodation training group compared to the comparative group. This study proved the effectiveness of vision training device(OTUS) on functional myopia, but further clinical trials are judged necessary to prove the possibility of long-term control of the functional myopia.