• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권9호
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• pp.4484-4501
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• 2019

In this paper, we put forward a delay-aware secure maximum distance separable (MDS) coded caching scheme to resist the eavesdropping attacks for device-to-device (D2D) content sharing by combining MDS coding with distributed caching. In particular, we define the average system delay to show the potential coupling of delay-content awareness, and learn the secure constraints to ensure that randomly distributed eavesdroppers cannot obtain enough encoded packets to recover their desired contents. Accordingly, we model such a caching problem as an optimization problem to minimize the average system delay with secure constraints and simplify it to its convex relaxation. Then we develop a delay-aware secure MDS coded caching algorithm to obtain the optimal caching policy. Extensive numerical results are provided to demonstrate the excellent performance of our proposed algorithm. Compared with the random coded caching scheme, uniform coded caching scheme and popularity based coded caching scheme, our proposed scheme has 3.7%, 3.3% and 0.7% performance gains, respectively.

• 한국정밀공학회지
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• 제12권8호
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• pp.73-85
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• 1995

The sensor system to measure the distance precisely from the center of the sensor system to the obstacle is needed to recognize the surrounding environments, and the sensor system is to be calibrated thoroughly to get the range information exactly. This study covers the calibration of the active range sensor which consists of camera and laser slit emitting device, and provides the equations to get the 3D range data. This can be possible by obtaining the extrinsic parameters of laser slit emitting device through image processing the slits measured during the constant distance intervals and the intrinsic parameters from the calibration of camera. The 3D range data equation derived from the simple geometric assumptions is proved to be applicable to the general cases using the calibration parameters. Also the exact 3D range data were obtained to the object from the real experiment.

• Journal of information and communication convergence engineering
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• 제18권3호
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• pp.188-193
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• 2020

In this paper, we examine whether the 3D image experience through a light-field display device showed the difference in the arousal of the user compared with the 2D image experience. For our experiment, the Looking Glass^TM (LG) was used as a lightfield display device that provided 3D images, and 2D images were provided by digital and printed images. The subject's facial behavior during each media experience was recorded for analysis and the degree of arousal was measured by FaceReader^TM. As a result, the first image presented in the first order among the three kinds of images showed that there was a statistical difference in the degree of arousal between the three media. However, no significant differences were found between the three media in the other images. This may be because the arousal did not increase from the experience of the second image through the LG, owing to habituation. In conclusion, the 3D imaging experience may appear in the beginning, but does not continue.

• 한국멀티미디어학회논문지
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• 제15권10호
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• pp.1264-1272
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• 2012

3차원 볼륨렌더링 방법은 인체의 외형뿐만 아니라 내부의 모습도 투과하여 보여줄 수 있기 때문에 의료영상 분야에서 널리 사용된다. 기존의 의료영상 장비는 볼륨렌더링 방법을 이용하여 다양한 3차원 영상을 제공하고 있다. 최근 의료영상 분야에서는 휴대성의 장점을 가진 스마트 기기를 도입함으로써 기존 의료영상 분야의 결과물을 의사와 환자들 사이에서 소통이 원활하게 하려는 연구가 활발히 진행되고 있다. 본 논문에서는 비교적 저 사양인 휴대용 스마트 기기에서 3차원 볼륨데이터를 가시화하기 위하여 2차원 텍스쳐를 활용하는 방법을 제안하고 다양한 2차원, 3차원 진단영상을 제공하는 휴대용 의료영상 가시화 시스템을 제안한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.86-89
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• 2002

We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is 10[mN/m]. In processing of a device manufacture, we can see the process is good from the change of a surface pressure for organic thin films and transfer ratio of area per molecule. The structure of manufactured device is Au/Poly-${\gamma}$ Benzyl $_D$-Glutamate/Al and Au/Poly-${\gamma}$ Benzyl $_D$-Glutamate/Au; the number of accumulated layers is 1, 3, 5 and 7. Also, we then examined of the MIM device by means of I-V. The I-V characteristic of the device is measured from 0 to +2[V]. We determined electrochemical measurement by using cyclic voltammetry with a three-electrode system. LB film accumulated by monolayer on an ITO. In the cyclicvoltammetry, An Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode measured in $LiBF_4$ solution, stable up to 0.9V vs. Ag/AgCl.

• 한국CDE학회논문집
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• 제14권6호
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• pp.415-423
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• 2009

Because of the fast changing car design and increasing facilities, manufacturing process of cars is getting more complex now a days. Particularly, car manufacturing system that consist of automated devices, applies various simulation techniques to validate device motion and detect collision. To cope with this problem, traditional manufacturing system deployed test-run with the real devices. However, increased computing power in a contemporary manufacturing system changes it into realistic 3D simulation environment. Similarly, managed device data that was generated using 2D traditionally, can be converted to 3D realistic simulation. The existing problem with 3D simulation is disjoint data interaction between different work stations. Consequently, JIGs, fixing the car part accurately, are changed according to fixing position on the part or a part shape properties. In practice, the 3D JIG data has to be managed according to kinematic information, but not of its features. However, generating kinematic information to the 3D model repeatedly according to frequent change in part is not explained in current literatures. To fill this knowledge gap, this paper suggests an improving method of rendering 3D JIG kinematics information to simulation model. Thereafter, it shows the result of implementation.

• 전자공학회논문지
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• 제52권12호
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• pp.22-31
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• 2015

최근, 3GPP (3rd Generation Partnership Project) 에서는 폭발적으로 증가하고 있는 모바일 데이터 트래픽을 수용하기 위하여 기기 간 직접(Device-to-Device, D2D) 통신을 개발하고 이에 대한 연구가 활발히 진행되고 있다. D2D 통신을 위해 이용되는 링크를 사이드링크라 하며, 사이드링크는 낮은 PAPR (Peak to Average Power Ratio)을 위해 SC-FDMA (Single Carrier-Frequency Division Multiple Access)를 기반으로 한다. 또한, DMRS (DeModulation Reference Signal)를 사용함으로써 MIMO (Multiple Input Multiple Output) 전송이 가능하게 한다. 본 논문에서는 D2D 통신에서 사이드링크를 위한 DFT 기반 채널 추정 기법을 제안한다. 제안 기법은 빠른 속도로 움직이는 사용자의 채널 추정이 가능하도록 2-D MMSE (2-Dimensional Minimum Mean Square Error) 보간 기법을 사용한다. 시스템 레벨 시뮬레이션은 3GPP LTE-Advanced 시스템의 20MHz 대역을 기반으로 이루어 졌으며, 시뮬레이션 결과 제안한 채널 추정 기법을 통해 기존 기법보다 SINR(Signal-to-Interference-plus-Noise Ratio), 전송률 및 스펙트럼 효율 측면에서 성능 향상을 가져다주는 것을 확인하였다.

• 한국생산제조학회지
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• 제23권3호
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• pp.218-222
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• 2014

A 3D printer was used to fabricate a micro-TAS system for biomedical applications. A polymeric medical device fabrication based on a 3D printer can be performed at atmospheric conditions. A CAD- and CAM-based system is a flexible method to design medical components, and a 3D printer is a suitable device to perform this task. In this research, a 100-micron-wide fluidic channel was fabricated with a high-aspect ratio. A cross-sectional SEM image confirmed its possible usage in a micro-reactor using 3D printers. CNC-machined samples were compared to 3D printer-fabricated samples, and the advantages and disadvantages were discussed. Based on the SEM images, the surface roughness of the 3D printed reactor was not affected by wet or dry conditions due to its manufacturing principle. An aspect ratio of 5 to 1 was achievable with 100-${\mu}$ m-wide fluid channels. No melting was found, and the shape of channels was straight enough to be used for micro reactors.

• 대한전자공학회논문지
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• 제18권3호
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• pp.25-34
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• 1981

전하결합소자(charge coupled device)의 제작에 필요한 다중전극구조를 실현하기 위하여 알루미늄양극산화방법을 실험적으로 조사하였다. 양극산화의 전해질용액으로 2% ammonium tartrate를 사용하고, 산화전압을 30∼35 volt로 하여 2시간 정도 산화할 때 형성되는 Al2O3의 두께는 400∼500A이었고 절연파괴전압은 30volt 정도였다. 이와 같은 Al2O3의 성질을 이용하여 CCD transversal 저역여파기를 제작하였다. 17개의 tap coefficient를 갖는 저역파기의 stop band attenuation은 약 22dB 이었으며 사용가능한 주파수 범위는 3 KHz로부터 100KHz까지였다.

• 한국전자통신학회논문지
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• 제16권6호
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• pp.1053-1058
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• 2021

본 논문은 능동소자에 인가되는 게이트 바이어스 전압을 가변하여 X-, K- 및 Ka-대역 신호를 선택적으로 변환할 수 있는 다중대역 혼합기를 제안하였다. 제안한 다중대역 혼합기는 LO 전력 +6 dBm으로 구동하였고 X-대역의 경우, 게이트 바이어스 전압 -0.8 V에서 변환손실 -10 dB 특성, K-대역에서 게이트 바이어스 전압 -0.3 V에서 변환손실 -9 dB 특성, Ka-대역에서는 게이트 바이어스 전압 -0.2 V에서 변환손실 -7.0 dB 특성을 나타내었다. 모든 대역에서 1-dB 압축점 (P1dB)은 +0.5 dBm 특성을 나타내었다.