• Journal of Information Processing Systems
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• 제16권1호
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• pp.49-60
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• 2020

To solve the edge ringing or block effect caused by the partial differential diffusion in image enhancement domain, a new image enhancement algorithm based on bidirectional diffusion, which smooths the flat region or isolated noise region and sharpens the edge region in different types of defect images on aviation composites, is presented. Taking the image pixel's neighborhood intensity and spatial characteristics as the attribute descriptor, the presented bidirectional diffusion model adaptively chooses different diffusion criteria in different defect image regions, which are elaborated are as follows. The forward diffusion is adopted to denoise along the pixel's gradient direction and edge direction in the pixel's smoothing area while the backward diffusion is used to sharpen along the pixel's gradient direction and the forward diffusion is used to smooth along the pixel's edge direction in the pixel's edge region. The comparison experiments were implemented in the delamination, inclusion, channel, shrinkage, blowhole and crack defect images, and the comparison results indicate that our algorithm not only preserves the image feature better but also improves the image contrast more obviously.

• 한국위성정보통신학회논문지
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• 제9권2호
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• pp.12-17
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• 2014

본 논문에서는 고전압에서 동작하는 마이크로칩의 안정하고 튼튼한 정전기 보호 성능을 구현하기 위해 이중 극성 소오스를 갖는 DPS_EDNMOS 변형소자가 제안되었다. 제안된 DPS는 N+ 소오스로 부터 전자 풍부 영역이 측면 확산되는 것을 방지하기 위해 N+ 소오스 측에 P+ 확산층을 의도적으로 삽입한 구조이다. 시뮬레이션 결과에 의하면 삽입된 P+ 확산층은 고전자 주입에 의해 발생하는 깊은 전자채널의 형성을 효과적으로 막아주고 있음을 알 수 있었다. 따라서 종래의 EDNMOS 표준소자에서 문제시 되었던 더블 스냅백 현상을 해결할 수 있었다.

• 진공이야기
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• 제3권3호
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• pp.15-18
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• 2016

In future wearable electronic systems, 3-dimensional (3D) devices have attracted much attention due to their high density integration and low-power functionality. Among 3D devices, gate-all-around (GAA) nanowire transistor provides superior gate controllability, resulting in suppressing short channel effect and other drawbacks in 2D metal-oxide-semiconductor field-effect transistor (MOSFET). Silicon nanowires (SiNWs) are the most promising building block for GAA structure device due to their compatibility with the current Si-based ultra large scale integration (ULSI) technology. Moreover, the theoretical limit for subthreshold swing (SS) of MOSFET is 60 mV/dec at room temperature, which causes the increase in Ioff current. To overcome theoretical limit for the SS, it is crucial that research into new types of device concepts should be performed. In our present studies, we have experimentally demonstrated feedback FET (FBFET) and tunnel FET (TFET) with sub-60 mV/dec based on SiNWs. Also, we fabricated SiNW based complementary TFET (c-TFET) and SiNW complementary metal-oxide-semiconductor (CMOS) inverter. Our research demonstrates the promising potential of SiNW electronic devices for future wearable electronic systems.

• 동의생리병리학회지
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• 제20권6호
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• pp.1620-1624
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• 2006

This study was performed to investigate a vasodilatory efficacy and its underlying mechanisms of the mixture of Cnidium officinale, Petasites japonicus and Coptis chinensis (CPC), CPC relaxed rat aortic vascular strips in endothelium-independant manner precontracted with phenylephrine or KCI(50mM), but the magnitude of relaxation was greater in KCI induced contraction. L-NAME, iNOS inhibitor, and methylen blue(MB), cGMP inhibitor, did not attenuate the relaxation responses of CPC. Furthermore, the contraction by increaseing $Ca^{2+}$ concentration (0.3-10.0mM) to a $Ca^{2+}$-free high $K^+$ (60mM) was significantly reduced by CPC pretreatment. These results suggest that the relaxation effect of CPC is related with the block of $Ca^{2+}$ influx via $Ca^{2+}$ channel.

• 비파괴검사학회지
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• 제22권1호
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• pp.59-64
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• 2002

CANDU형 핵연료채널 압력관(Zr-2.5%Nb)과 calandria관(Zircaloy-2)에 대한 원격장 와전류탐상의 자계분포특성을 파악하기 위하여 유한요소 해석을 수행하였다. 압력관과 칼란드리아관의 전자기장 분포와 위상각 해석을 통하여 최적 검사 주파수와 감지코일의 위치를 평가하였다. 또한 축대칭 구조물(Al-ring과 Al-block)이 공존시 파라미터해석을 통하여 원격장 와전류의 특성을 평가하였다.

• ETRI Journal
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• 제43권2호
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• pp.232-245
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• 2021

As wireless communication continues to develop in limited frequency resource environments, it is becoming important to identify the state of spectrum utilization and predict the amount needed in future. It is essential to collect reliable information for data analysis. This paper introduces a platform that enables the gathering of the scheduling information of a long-term evolution (LTE) cellular system without connecting to the network. A typical LTE terminal can confirm its assigned resource information using the configuration parameters delivered from a network. However, our platform receives and captures only the LTE signal over the air and then enables the estimation of the data relevant to scheduling for all terminals within an LTE cell. After extracting the control channel signal without loss from all LTE subframes, it detects valid downlink control information using the proposed algorithm, which is based on the error vector magnitude of depatterned symbols. We verify the reliability of the developed platform by comparing it with real data from mobile phones and service operators. The average difference in resource block utilization is only 0.28%.

• International Journal of Internet, Broadcasting and Communication
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• 제13권4호
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• pp.55-65
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• 2021

The purpose of this paper is to present the Over-The-Top (OTT) platforms' strategies for two-sided markets. For this, we examine six strategic factors influencing OTT's success in Korea. The analysis reveals, among six OTTs, Netflix utilizes five strategic factors except the same-side network effects. OTTs from pay TV operators and channel providers tend to block the cross-side network effects on the opponent OTTs, because they think their giveaway to content providers is in vein, if the invested content by them would be consumed on opponent rival platforms. Interesting is that after experiencing a negative association between the market entry of Netflix and the subscription revenue growth rate of pay TV services, pay TV operators utilize the same-side network effects by offering hybrid services in partnership with global OTTs like Netflix, Disney+ which are considered as a complementary OTT. In conclusion, it is suggested to target a new connected TV based OTT service offering with collaboration with Korean TV device manufacturers for Korean OTTs' global strategy, because Netflix-like global market expansion is not easy for them to cover their content cost.

• ETRI Journal
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• 제43권1호
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• pp.109-119
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• 2021

Self-recovery is a tamper-detection and image recovery methods based on data hiding. It generates two types of data and embeds them into the original image: authentication data for tamper detection and reference data for image recovery. In this paper, a region-based scalable self-recovery (RSS) method is proposed for salient-object images. As the images consist of two main regions, the region of interest (ROI) and the region of non-interest (RONI), the proposed method is aimed at achieving higher reconstruction quality for the ROI. Moreover, tamper tolerability is improved by using scalable recovery. In the RSS method, separate reference data are generated for the ROI and RONI. Initially, two compressed bitstreams at different rates are generated using the embedded zero-block coding source encoder. Subsequently, each bitstream is divided into several parts, which are protected through various redundancy rates, using the Reed-Solomon channel encoder. The proposed method is tested on 10 000 salient-object images from the MSRA database. The results show that the RSS method, compared to related methods, improves reconstruction quality and tamper tolerability by approximately 30% and 15%, respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권4호
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• pp.1373-1391
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• 2022

We investigate mobile multiple-input multiple-output (MIMO) molecular communication via diffusion (MCvD) system which is consisted of two source nodes, two destination nodes and one relay node in the mobile three-dimensional channel. First, the combinations of decode-and-forward (DF) relaying protocol and network coding (NC) scheme are implemented at relay node. The adaptive thresholds at relay node and destination nodes can be obtained by maximum a posteriori (MAP) probability detection method. Then the mathematical expressions of the average bit error probability (BEP) of this mobile MIMO MCvD system based on DF and NC scheme are derived. Furthermore, in order to minimize the average BEP, we establish the optimization problem with optimization variables which include the ratio of the number of emitted molecules at two source nodes and the initial position of relay node. We put forward an iterative scheme based on block coordinate descent algorithm which can be used to solve the optimization problem and get optimal values of the optimization variables simultaneously. Finally, the numerical results reveal that the proposed iterative method has good convergence behavior. The average BEP performance of this system can be improved by performing the joint optimizations.

• 센서학회지
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• 제31권4호
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• pp.271-277
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• 2022

We analyzed the effects of the interface trap on the output characteristics of an inversion mode n-channel GaN Schottky barrier (SB)-MOSFET based on the N_it distribution using TCAD simulation. As interface trap number density (N_it) increased, the threshold voltage increased while the drain current density decreased. Under N_it=5.0×10¹⁰ cm^-2 condition, the threshold voltage was 3.2 V for V_DS=1 V, and the drain current density reduced to 2.4 mA/mm relative to the non-trap condition. Regardless of the N_it distribution type, there was an increase in the subthreshold swing (SS) following an increase in N_it. Under U-shaped N_it distribution, it was confirmed that the SS varied depending on the gate voltage. The interface fixed charge (Q_f) caused an shift in the threshold voltage and increased the off-state current collectively with the surface trap. In summary, GaN SB-MOSFET can be a building block for high power UV optoelectronic circuit provided the surface state is significantly reduced.