• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.556-559
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• 2006

We successfully developed a high performance and highly reliable blazed GxL device with a high optical efficiency and a high contrast ratio. The device demonstrated superior resistance against a high power laser, which is suitable for a large-area laser projector. We operated the world's largest laser projection screen using this device at the 2005 World Exposition in Aichi, Japan, problem free.

• 센서학회지
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• 제26권5호
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• pp.301-305
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• 2017

This paper presents a wearable human health-monitoring band. The band consists of a body temperature detector (BTD) and a hear rate detector (HRD). The BTD and HRD are realized using an inkjet-printed flexible temperature sensor and a commercial heart rate sensor module, respectively. The sensitivity of the fabricated BTD was found to be $-31/^{\circ}C$ with a linearity of 99.82%. The HRD using the commercial heart rate sensor module has a good performance with a standard deviation of 0.85 between the data of a commercial smart watch and the fabricated HRD.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권4호
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• pp.1415-1435
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• 2018

Resource allocation in device-to-device (D2D) aided cellular systems, in which the proximity users are allowed to communicate directly with each other without relying on the intervention of base stations (BSs), is investigated in this paper. A new uplink resource allocation policy is proposed by exploiting the relationship between D2D-access probability and channel gain among variant devices, such as cellular user equipments (CUEs), D2D user equipments (DUEs) and BSs, etc., under the constraints of their minimum signal to interference-plus-noise ratio (SINR) requirements. Furthermore, the proposed resource-allocation problem can be formulated as the cost function of "maximizing the number of simultaneously activated D2D pairs subject to the SINR constraints at both CUEs and DUEs". Numerical results relying on system-level simulations show that the proposed scheme is capable of substantially improving both the D2D-access probability and the network throughput without sacrificing the performance of conventional CUEs.

• Journal of Magnetics
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• 제10권2호
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• pp.66-70
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• 2005

The junction properties between the ferromagnet (FM) and two-dimensional electron gas (2DEG) system are crucial to develop spin electronic devices. Two types of 2DEG layer, InAs and GaAs channel heterostructures, are fabricated to compare the junction properties of the two systems. InAs-based 2DEG layer with low trans-mission barrier contacts FM and shows ohmic behavior. GaAs-based 2DEG layer with $Al_2O_3$ tunneling layer is also prepared. During heat treatment at the furnace, arsenic gas was evaporated and top AlAs layer was converted to aluminum oxide layer. This new method of forming spin injection barrier on 2DEG system is very efficient to obtain tunneling behavior. In the potentiometric measurement, spin-orbit coupling of 2DEG layer is observed in the interface between FM and InAs channel 2DEG layers, which proves the efficient junction property of spin injection barrier.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.597-599
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• 2022

IoT 디바이스에서 on-device AI를 수행할 때, 타겟 서비스나 디바이스의 환경에 따라 필요한 AI 모델이 달라질 수 있다. 또한, 기존 AI 모델도 federated learning과 같이 추가적인 데이터를 이용해 트레이닝을 하거나 보다 향상된 새로운 기법을 사용하는 등 업데이트가 일어날 수 있다. 이에 따라 IoT 디바이스에서 양질의 AI 서비스를 수행하기 위해서는 상황에 따라 필요한 AI 모델을 선택적으로 사용하거나 최적화된 최신 버전의 AI 모델로 업데이트 할 수 있어야 한다. 본 논문에서는 이를 지원하기 위한 AI 모델 레포지토리를 제안한다. 레포지토리는 AI 모델의 등록, 검색, 관리 및 배포를 지원하며 실사용을 위한 웹 포털을 포함한다. 제안하는 시스템의 실효성 확인을 위해 Node.js와 Vue.js로 구현하여 동작을 확인하였다.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.442-448
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• 2022

Intermediate-level radioactive waste (ILW) is not subject to legal approval for cave disposal in Korea. To solve this problem, a spent resin treatment device that separates ¹⁴C-containing resin from zeolite/activated carbon and desorbs ¹⁴C through a microwave device has been developed. In this study, we evaluated the radiological safety of the operators performing repair work in the event of a failure in such a device treating 1 ton of spent resin mixture per day. Based on the safety evaluation results, it is possible to formulate a design plan that can ensure the safety of workers while developing a commercialized device. When each component of the resin treatment device can be repaired from the outside, the maximum and minimum allowable repair times are calculated as 263.2 h and 27.7 h for the ¹⁴C-detached resin storage tank and zeolite/activated carbon storage tank, respectively. For at least 6 h per quarter, the worker's annual dose limit remains within 50 mSv/year; further, over 5 years, it remained within 100 mSv. At least 6 h of repair time per quarter is considered, under conservative conditions, to verify the radiological safety of the worker during repair work within that time.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2535-2539
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• 2003

The haptic system becomes an essential device in the area of tele-operation, video entertainment and medical operation. To control a haptic device, impedance control method is widely used, but force sensor costs so much that open-loop control method is usually preferred for commercial purpose. In this case, modeled/un-modeled dynamics affects the performance of device. In this paper, we present a new 3DOF five-link type haptic device that we can reduce the effect of device dynamics and compensate its dynamics. We also evaluate its performance.

• 한국고분자학회지:고분자과학과기술
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• 제18권3호
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• pp.238-245
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• 2007

• Nuclear Engineering and Technology
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• 제50권6호
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• pp.937-943
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• 2018

Background: This work presents the performance of a novel electronic brachytherapy (EBT) device and radiotherapy (RT) experiments on both skin cancer cells and animals using the device. Methods and materials: The performance of the EBT device was evaluated by measuring and analyzing the dosimetric characteristics of X-rays generated from the device. The apoptosis of skin cancer cells was analyzed using B16F10 melanoma cancer cells. Animal experiments were performed using C57BL/6 mice. Results: The X-ray characteristics of the EBT device satisfied the accepted tolerance level for RT. The results of the RT experiments on the skin cancer cells show that a significant apoptosis induction occurred after irradiation with 50 kVp X-rays generated from the EBT device. Furthermore, the results of the animal RT experiments demonstrate that the superficial X-rays significantly delay the tumor growth and that the tumor growth delay induced by irradiation with low-energy X-rays was almost the same as that induced by irradiation with a high-energy electron beam. Conclusions: The developed new EBT device has almost the same therapeutic effect on the skin cancer with a conventional linear accelerator. Consequently, the EBT device can be practically used for human skin cancer treatment in the near future.

• 한국전자통신학회논문지
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• 제15권6호
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• pp.1113-1122
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• 2020

최근 묻지마식의 강력범죄가 계속 일어나면서 여성 및 노약자들의 피해가 심각해지고 있다. 기존 시스템으로는 CCTV는 많이 설치되어 있으나 범죄가 일어난 후 사후 조치에 그쳐 범죄를 예방하기에는 어려움이 많이 발생하고 있는 바 아파트나 빌딩등 음영지역과 폐쇄 공간등에서의 사건 사고를 본 장치를 통하여 범죄를 방지하고자 본 기술을 연구하여 제품과 소프트웨어를 개발한다. 범죄로 예상되는 행위,행동의 움직임의 특정 대상을 영상분석 빅데이터 기술과 융합 센서 기술을 이용하여 운영되고 있는 CCTV 장치 혹은 경보의 이벤트를 받고자 하는 특정장소에 통신기술을 이용하여 경보 신호를 보내주는 장치 개발한다. 본 개발 장치는 범죄 발생을 사전에 예측하여 실시간으로 범죄발생을 경보 신호로 처리하여 전송해주는 장치로 사용되는 소비자들에게 본 장치를 연구 개발하여 저가의 장치를 공급하며 단독형 장치와 서버를 구성하여 연결되는 장치를 제공하게 된다.