• 디지털콘텐츠학회 논문지
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• 제8권3호
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• pp.393-401
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• 2007

P2P systems have gained a lot of research interests and popularity over the years and have the capability to unleash and distribute awesome amounts of computing power, storage and bandwidths currently languishing - often underutilized - within corporate enterprises and every Internet connected home in the world. Since there is no central control over resources or devices and no before hand information about the resources or devices, device discovery remains a substantial problem in P2P environment. In this paper, we cover some of the current solutions to this problem and then propose our feed forward neural network (FFNN) based solution for device discovery in mobile P2P environment. We implements feed forward neural network (FFNN) trained with back propagation (BP) algorithm for device discovery and show, how large computation task can be distributed among such devices using agent technology. It also shows the possibility to use our architecture in home networking where devices have less storage capacity.

• 전기학회논문지
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• 제61권12호
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• pp.1843-1847
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• 2012

Piezo devices have large power density and simple structure. They can generate larger force than the conventional actuators. It has also wide bandwidth with fast response in a compact size. Thus the piezo devices are expected to be used widely in the future for small actuators with fast response time and large actuating force. However, the piezo actuators need high voltage with high driving current due to their large capacitive property. In this paper, we propose a simple method to drive piezo devices using voltage inversion circuit with coil inductance. Experiments with real circuit demonstrates that the proposed scheme can improve the energy efficiency very much.

• 디지털산업정보학회논문지
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• 제4권3호
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• pp.9-18
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• 2008

Mobile devices do not need the fixed network infrastructure in ad-hoc network, these devices communicate each other through the distributed control. Accordingly, mobile devices can discover several services using dynamic searching method and provide safely public ownership of these services. Ad-hoc network needs the distributed control and topology of dynamic network because the limited power for processing and network communication. This paper is devoted to provide the secure protocol that provides efficient services discovery using SDP(Service Discovery Protocol) and considers the security requirements. Proposed protocol provides the distributed control based on PKI without central server, the discovery of trusted service, secure telecommunication, the identification among mobile devices, and service access control by user authority.

• 대한의용생체공학회:의공학회지
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• 제33권3호
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• pp.155-162
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• 2012

Devices to measure the blood pressure of patients are being used without any calibration in a hospital. It is an important to show consistent values when any medical devices measure the same patients regardless they are sphygmomanometer or fully automatic electronic blood pressure meter. We compared sphygmomanometer and fully automatic electronic blood pressure meters with standard digital blood pressure monitor (SDBPM) to evaluate the consistency of the small healthy subjects. We measured the blood pressure from six healthy subjects (three of 20~40 years and three of 40~60 years old). Two sphygmomanometer and two fully automatic electronic blood pressure meters were used and compared with the SDBPM. Blood pressures measured from right and left arms each and were compared. All six healthy subjects showed normal blood pressure values. In general, left blood pressure values showed higher values than right side. Comparing SDBPM, with the other monitors, the systolic pressure showed ${\pm}$ 34.8% difference and ${\pm}$ 33.3% for the diastolic pressure. Correlation between SDBPM and Sphygmomanometer was 0.59~0.71, and 0.50~0.70 for fully automated digital BP monitors. It fell in grade-D when we apply the BHS(British hypertension society). AAMI(American association for the advancement of medical instrumentation) also showed unsatisfactory results for the mean value (${\leq}$ 5 mmHg) and standard deviation (${\leq}$ 8 mmHg). We tested sphygmomanometer and fully automatic electronic blood pressure meters and compared with a standard digital blood pressure monitor. All devices showed inconsistent blood pressures. A reliable calibration system is highly needed for all devices in all hospitals.

• 디지털융복합연구
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• 제18권10호
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• pp.443-452
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• 2020

현시대의 아동들에게 스마트 모바일 기기들을 활용한 교육은 아동미술교육 분야에서도 이제는 한 부분을 차지하고 있다. 펜이 탑재된 모바일 기기들과 스마트 태블릿PC들이 출시되면서 드로잉과 컬러링이 디지털 기기들로 가능해졌기 때문이다. 오늘날 아동들을 위한 컬러링 게임 콘텐츠들은 언제든지 애플리케이션 형태로 다운로드 받아 아동미술교육 현장에서 사용할 수 있게 되었다. 하지만 아동들을 위한 미술교육 효과를 가진 컬러링 기능성 게임들은 극히 적으며, 게임 안에 들어있는 미술 콘텐츠 요소들 또한 서비스되고 있는 모든 게임들이 대부분 비슷하며, 아동미술 표현기법 기능들도 부족한 상황이다. 본 연구는 아동들의 컬러링 활동을 도와주며 창의성과 상상력을 높일 수 있는 아동미술교육용 컬러링 기능성 게임 콘텐츠 개발의 중요성을 인지하고 기존 오프라인 아동미술교육 현장에서 시행되는 검증된 대표적인 미술표현기법들을 분석하여 아동미술 교육용 컬러링 게임 디지털 융복합 표현기법 콘텐츠의 개발방향과 요소들을 중심으로 연구하여 제시하고자 한다.

• 한국콘텐츠학회논문지
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• 제21권2호
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• pp.707-717
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• 2021

본 연구는 디지털기기에서 앱을 활용한 그림검사가 가능한지를 탐색해보고자 게임 중독군을 대상으로 '나무에서 사과 따는 사람 그리기(Person Picking an Apple from a Tree: 이하 PPAT)' 그림 검사를 바탕으로 진단을 확인하여 미술치료에서의 그림검사 앱을 활용할 수 있는 근거를 마련할 수 있는지를 살펴보는데 목적이 있다. PPAT 그림검사는 사람이 사과를 어떤 식으로 따는지 문제해결력을 검증하는데 유용하고 이에 대한 신뢰도, 타당도가 높은 검사이다. 본 연구를 통해 살펴본 결과, 디지털 기기에서 앱을 활용한 PPAT 그림검사의 형식척도(Formal Elements Art Therapy Scale:이하 FEATS) 항목 14개 중 '문제해결력' 항목에서 인터넷 과몰입군이 일반사용자군 보다 낮은 점수를 받았는데, 과몰입군의 경우 사과를 향해 손을 뻗지 않고 있거나, 사과가 떨어지는 그림, 합리적인지지 기반 없이 사과를 따는 방법으로 사과를 따른 모습을 표현했다. 본 연구에서 발견한 내용은 디지털 기기에서 앱을 사용한 PPAT 그림 검사가 본래의 목적인 '문제해결력'을 유의미하게 드러내었다는 점은 앞으로 디지털 기기를 활용하여 인터넷 과몰입 대상자들을 위한 심리치료적 개입뿐만 아니라 디지털 기기를 익숙하게 활용하는 사용자들에게는 PPAT 그림검사 앱을 활용할 수 있다는 점에서 연구의 의의가 있다.

• 대한청각학회지
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• 제18권3호
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• pp.105-111
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• 2014

Assistive listening devices (ALDs) refer to various types of amplification equipment designed to improve the communication of individuals with hard of hearing to enhance the accessibility to speech signal when individual hearing instruments are not sufficient. There are many types of ALDs to overcome a triangle of speech to noise ratio (SNR) problems, noise, distance, and reverberation. ALDs vary in their internal electronic mechanisms ranging from simple hard-wire microphone-amplifier units to more sophisticated broadcasting systems. They usually use microphones to capture an audio source and broadcast it wirelessly over a frequency modulation (FM), infra-red, induction loop, or other transmission techniques. The seven types of ALDs are introduced including hardwire devices, FM sound system, infra-red sound system, induction loop system, telephone listening devices, television, and alert/alarm system. Further development of digital wireless technology in hearing instruments will make possible direct communication with ALDs without any accessories in the near future. There are two technology solutions for digital wireless hearing instruments improving SNR and convenience. One is near-field magnetic induction combined with Bluetooth radio frequency (RF) transmission or proprietary RF transmission and the other is proprietary RF transmission alone. Recently launched digital wireless hearing aid applying this new technology can communicate from the hearing instrument to personal computer, phones, Wi-Fi, alert systems, and ALDs via iPhone, iPad, and iPod. However, it comes with its own iOS application offering a range of features but there is no option for Android users as of this moment.

• 한국통신학회논문지
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• 제11권3호
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• pp.153-163
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• 1986

III-V족 복합물 반도체인 GaAs를 이용한 초고속소자는 DBS(Direct Broadcast Satellite), 광통신, microwave 및 digital 집적회로에 널리 사용되낟. 이와 같은 GaAS를 substrate재료로 D/E MESFET'S을 이용한 4Kx4bit SRAM, HEMT'S에 의한 4K bit SRAM과 X-band용 수신기전단부의 MMIC화가 보고되였고, 3차원적인 광집적회로의 연구도 가까운 장래에 완성될 것이다. 본 논문에서는 현재까지 널리 사용되어온 GaAs반도체 재료, 제조공정기술, 소자응용과 집적회로 설계면을 고찰 검토한다. 마지막으로 초고속소자의 전망을 논의한다.

• 대한의용생체공학회:의공학회지
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• 제44권4호
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• pp.264-274
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• 2023

Purpose: The objective is to extract insights that can contribute to the formulation of harmonized international policies and support measures for innovative medical devices and management systems. This study aims to propose effective strategies for future medical device innovation and healthcare delivery. Results: It investigates technological advancements, regulatory approval systems, insurance policies, and successful commercialization cases in South Korea, the United States, and the European Union. In 2018, the FDA implemented insurance coverage for Software as a Medical Device (SaMD) and recognized insurance coverage for Digital Therapeutics (DTx). Germany is a country that ensures permanent reimbursement for healthcare applications since 2020, making it the first country to provide legal health insurance coverage for fostering a digital ecosystem. Conclusion: The findings of this research highlight the importance of cultivating a supportive regulatory and environmental framework to facilitate the adoption of innovative medical devices. Continuous support for research and development (R&D) efforts by companies, along with the validation of clinical effectiveness, is crucial.

• 대한기계학회논문집A
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• 제28권12호
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• pp.1990-1996
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• 2004

This paper presents a nonlinearly modulated digital actuator (NMDA) for producing nano-precision digital stroke. The NMDA, composed of a digital microactuator and a nonlinear micromechanical modulator, purifies the stroke of the digital actuator in order to generate the high-precision displacement output required for nano-positioning devices. The function and concept of the nonlinear micromechanical modulator are equivalent to those of the nonlinear electrical limiters. The linear and nonlinear modulators, having an identical input and output strokes of 15.2${\mu}{\textrm}{m}$ and 5.4${\mu}{\textrm}{m}$, are designed, fabricated and tested, respectively. The linear and nonlinear modulators are linked to identical digital actuators in order to compare the characteristics of the linearly modulated microactuator (LMDA) and NMDA. In addition, an identical linear modulator is attached to the output ports of LMDA and NMDA. The NMDA shows the repeatability of 12.3$\pm$2.9nm, superior to that of 27.8$\pm$2.9nm achieved by LMDA. When the identical linear modulator is connected to LMDA and NMDA, the final modulated output from NMDA shows the repeatability of 10.3$\pm$7.2nm, superior to that of 15.7$\pm$7.7nm from LMDA. We experimentally verify the displacement purifying capability of the nonlinear mechanical modulator, applicable to nano-precision positioning devices and systems.