Context 정보를 이용한 어플리케이션 접근제어 기법에 관한 연구

이용한(Yonghan Lee),김영갑(Young-Gab Kim),백두권(Doo-Kwon Baik) 한국정보과학회 2011 한국정보과학회 학술발표논문집 Vol.38 No.2C

접근제어는 정보보안의 중요한 연구분야 중 하나로서 MAC DAC RBAC 등 다양한 방식이 존재해 왔고 새로운 응용모델이 제안되고 있다. 그러나 복잡한 처리규칙을 가진 어플리케이션의 접근제어에 대해서는 전문적인 모델이 없었다. 본 논문에서는 context 정보를 이용하여 어플리케이션에 대한 접근제어를 위한 모델로서 CIAAC (Context Information-based Application Access Control)를 제안하고 각 세부 구성요소에 대해 기술한다. CIAAC는 SC (Subject Context) OC (Object Context) S-ACR (Subject Access Control Rule) O-ACR (Object Access Control Rule) AC (Access Controller)의 5가지 요소로 구성되어 있다. 본 논문에서 제안하는 CIAAC는 어플리케이션에서 요구하는 다양하고 복잡한 접근제어 요건을 유연하게 처리하기 위한 것이다. 이를 위하여 context를 subject 관점과 object 관점으로 나누고 context에 대한 접근제어 정책을 2차원 테이블 형식으로 직관적이고 단순하게 표현한다. 이는 실제 시스템으로 구현하는 작업을 용이하게 하며 어플리케이션에 포함된 접근제어 규칙을 외부로 분리함으로써 어플리케이션이 본연의 비즈니스 로직 처리에 집중하게 할 수 있다.

Electroabsorption modulator based on inverted-rib-type silicon waveguide including double graphene layers

Kim, Yonghan,Kwon, Min-Suk IOP 2017 Journal of optics Vol.19 No.4

<P>We investigate, theoretically, a compact graphene-based electroabsorption modulator (EAM). The compactness of the EAM arises from an inverted-rib-type (IRT) silicon waveguide including a graphene–oxide–graphene stack. The EAM consists of input and output waveguides, which are conventional silicon strip waveguides, and the IRT waveguide efficiently connected to them through tapering regions. The stack is located in the region where the fundamental transverse electric mode of the IRT waveguide is mainly confined. Hence, the IRT waveguide mode strongly interacts with the graphene layers. Moreover, the IRT waveguide can be realized without complex high-precision processes. The calculated modulation depth of the IRT waveguide is 0.41 dB <I>μ</I>m<SUP>−1</SUP> when the chemical potential of graphene is tuned between 0.2 and 0.6 eV. It is more than two times larger than those of previous graphene-covered silicon waveguides. The EAM, with a 3 dB extinction ratio, employs an IRT waveguide of length 7–8 <I>μ</I>m. This EAM is analyzed and found to have an optical bandwidth of 100 nm, an electrical bandwidth of up to 46.4 GHz, and energy consumption smaller than 630 fJ bit<SUP>−1</SUP>. Such EAMs based on IRT waveguides may play an important role in off-chip optical interconnection.</P>

T1 Map-Based Radiomics for Prediction of Left Ventricular Reverse Remodeling in Patients With Nonischemic Dilated Cardiomyopathy

Chang Suyon,Han Kyunghwa,Kwon Yonghan,Kim Lina,Hwang Seunghyun,Kim Hwiyoung,Choi Byoung Wook 대한영상의학회 2023 Korean Journal of Radiology Vol.24 No.5

Objective: This study aimed to develop and validate models using radiomics features on a native T1 map from cardiac magnetic resonance (CMR) to predict left ventricular reverse remodeling (LVRR) in patients with nonischemic dilated cardiomyopathy (NIDCM). Materials and Methods: Data from 274 patients with NIDCM who underwent CMR imaging with T1 mapping at Severance Hospital between April 2012 and December 2018 were retrospectively reviewed. Radiomic features were extracted from the native T1 maps. LVRR was determined using echocardiography performed ≥ 180 days after the CMR. The radiomics score was generated using the least absolute shrinkage and selection operator logistic regression models. Clinical, clinical + late gadolinium enhancement (LGE), clinical + radiomics, and clinical + LGE + radiomics models were built using a logistic regression method to predict LVRR. For internal validation of the result, bootstrap validation with 1000 resampling iterations was performed, and the optimism-corrected area under the receiver operating characteristic curve (AUC) with 95% confidence interval (CI) was computed. Model performance was compared using AUC with the DeLong test and bootstrap. Results: Among 274 patients, 123 (44.9%) were classified as LVRR-positive and 151 (55.1%) as LVRR-negative. The optimismcorrected AUC of the radiomics model in internal validation with bootstrapping was 0.753 (95% CI, 0.698–0.813). The clinical + radiomics model revealed a higher optimism-corrected AUC than that of the clinical + LGE model (0.794 vs. 0.716; difference, 0.078 [99% CI, 0.003–0.151]). The clinical + LGE + radiomics model significantly improved the prediction of LVRR compared with the clinical + LGE model (optimism-corrected AUC of 0.811 vs. 0.716; difference, 0.095 [99% CI, 0.022–0.139]). Conclusion: The radiomic characteristics extracted from a non-enhanced T1 map may improve the prediction of LVRR and offer added value over traditional LGE in patients with NIDCM. Additional external validation research is required.

Bulk-Silicon-Based Waveguides and Bends Fabricated Using Silicon Wet Etching: Properties and Limits

Bonwoo Ku,Kyoung-Soo Kim,Yonghan Kim,Min-Suk Kwon IEEE 2017 Journal of Lightwave Technology Vol.35 No.18

<P>We develop a process of fabricating silicon waveguides and devices using a bulk silicon substrate. The fabrication process mainly consists of one silicon dry etching and one silicon wet etching. The use of silicon wet etching makes the process simple and inexpensive. Because of the anisotropic nature of silicon wet etching, the bulk-silicon-based (BSB) waveguide made by the process consists of an inverted-trapezoidal core on a rectangular pedestal and a trapezoidal base beneath the pedestal. In addition, geometrically smooth BSB waveguide bends can be achieved when the radii of curvature of the bends are sufficiently large. The propagation loss of the BSB waveguide depends on wet etching conditions and it is 4.0 or 0.79 dB/cm for transverse-magnetic polarization. It is confirmed that the minimum radius of curvature of the BSB waveguide bend is 500 mu m. The BSB waveguides and bends are expected to be used to implement low-cost sensors with simple geometry.</P>

Compact Silicon Slot Waveguide Intersection Based on Mode Transformation and Multimode Interference

Kim, Kyoung-Soo,Vuong, Quoc Viet,Kim, Yonghan,Kwon, Min-Suk IEEE 2017 IEEE photonics journal Vol.9 No.6

<P>Silicon slot waveguide intersections are necessary for photonic-integrated circuits based on silicon slot waveguides. We theoretically investigate a compact silicon slot waveguide intersection, which consists of mode transformers and a multimode strip waveguide crossing. The mode transformer before the crossing converts the slot waveguide mode into strip waveguide modes with amplitudes and phases appropriate for efficient operation of the crossing, which is based on multimode interference. The reverse conversion happens in the mode transformer after the crossing. The investigated intersection has a throughput of −0.078 dB, a crosstalk of −41 dB, and a footprint of 79.2 μm<SUP>2</SUP>. Its properties are better than those of previous silicon slot waveguide intersections, and especially its footprint is less than 33% of the previous ones. The intersection may be used for matrix switches based on silicon slot waveguides.</P>

Teleoperation of a platoon of distributed wheeled mobile robots with predictive display

Ha, Changsu,Yoon, Jaemin,Kim, Changu,Lee, Yonghan,Kwon, Seongjin,Lee, Dongjun Springer-Verlag 2018 Autonomous robots Vol.42 No.8

설정온도별 잉여 태양에너지 산정

윤용철 ( Yongcheol Yoon ),서원명 ( Wonmyung Suh ),배용한 ( Yonghan Bae ),권순주 ( Soonjoo Kwon ),임재운 ( Jaewoon Leem ) 한국농공학회 2010 한국농공학회 학술대회초록집 Vol.2010 No.-

본 연구에서는 주간동안 온실 내에서 발생되는 잉여 태양에너지를 분석하고, 또한 태양에너지의 적정 축열시스템 설계의 기초자료를 축척할 목적으로 수행하였으며, 표준기상년(TMY: Typical Meteorological Year) 데이터를 이용하여 온실 형태별 설정온도를 변화시켜 잉여 태양에너지 및 소요 난방에너지 변화의 경향을 분석하였다. 동일한 설정온도에서의 잉여태양에너지나 소요 난방에너지를 분석할 경우, 지역이나 온실종류에 따른 에너지의 량을 상대적으로 검토할 수는 있지만, 설정온도의 변화에 따른 에너지의 검토는 불가능하다. 이에 주·야간 설정온도 및 환기설정온도는 각각 2.0℃간격, 3단계로 변화시켰으며 주·야간 온도 중 하나는 일정하게 유지하고 다른 하나를 변화시켰을 경우에는 2.5℃간격, 4단계로 하였다. 온실형태는 07-자동화-1형 및 08-자동화-1형과 07-단동-1형 및 07-단동-3형이며 대상지역은 제주, 광주, 수원으로 하였다. 주·야간 설정온도를 단계별로 증가시킨 경우, 온실형태와 지역별로 잉여 태양에너지는 최대 2.0∼6.9%정도 증가하여 그 증가폭은 미미하지만 다소 완만히 증가함을 알 수 있었다. 그리고 소요 난방에너지는 최대 29.7∼50.0%정도 증가하여 잉여 태양에너지의 증가율 보다 훨씬 큰 폭으로 증가하였다. 환기 설정온도를 단계별로 증가시킨 경우, 자동화 온실은 지역별로 잉여 태양에너지는 최대 -9.9%∼-35.8%정도로 감소하는 것으로 나타났다. 그리고 단동형 온실은 지역별로 최대 -5.1%∼-13.4%정도로 감소하는 것으로 나타나 자동화 온실에 비해 감소의 폭이 상대적으로 작았다. 또한 소요 난방에너지는 온실형태 및 지역별로 다소 증가하거나 감소하는 경우도 있었지만, 그 영향은 아주 미미한 것으로 나타났다. 주간의 설정온도만 단계별로 증가시킨 경우, 잉여태양에너지는 온실형태와 지역별로 뚜렷한 변화의 경향을 알 수 없었다. 그러나 소요난방에너지의 경우, 온실형태와 지역별로 최대 14.3∼27.9%정도 증가하는 것으로 나타났다. 야간의 설정온도만 단계별로 증가시킨 경우, 잉여 태양에너지는 주간의 설정온도를 변화시킨 경우와 마찬가지로 온실형태와 지역별로 뚜렷한 변화의 경향을 알 수 없었다. 그러나 소요 난방에너지의 경우, 온실형태와 지역별로 최대 40.2∼66.4%정도 증가하는 것으로 나타났다.

연성 개폐식 구조물 케이블 설치 위치 검증을 위한 드론 활용방안

조한광(Cho, Hankwang),권나현(Nahyun Kwon),김상환(Kim, Sangwan),조재윤(Cho, Jaeyoun),안용한(Yonghan Ahn) 한국퍼실리티매니지먼트학회 2020 한국퍼실리티매니지먼트학회지 Vol.15 No.2

Indoor gymnasiums and dome stadiums are mostly made of fixed hard structures, which leads to economic loss due to the continuous operation of ventilation and lighting equipment. When the roof of a large space is installed by retractable method, it secures comfortable environment by natural light during the daytime and reduces ventilation costs. The retractable spaces can be constructed in hard and soft structures. In the case of soft structures, cables and membrane are the primary components. In order to install the cables, it is necessary to determine the location of the central part where each cable meets. However, the existing approach depending on only some workers shows a limited ability in investigating the appropriateness of the installed cables. Therefore, this study aims to propose a method to determine the installation location of the soft retractable structure cables based on the numerical data derived from drones. Factors that can inspect the construction quality of cables and membrane materials in the construction stage and construction completion stage were identified. Based on the construction guidelines of the Ministry of Land, Infrastructure and Transport of Korea (MOLIT), standard specifications, and relevant similar cases, the applicability of the method using the numerical data of the drone was investigated.