• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.62-62
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• 2003

Landsat TM 영상을 이용, 명암차가 높은 산악 지역에 적용해왔던 알고리즘을 개선하여 비교적 명암차가 낮고 넓게 분포하는 충적층 지역의 선구조를 추출하는 알고리즘을 개발하였다. 수치지형모델(OEM)에 대하여 Local Enhancement 를 이용해서 평탄한 지역을 선정하여 이로부터 충적층을 추출하였다. Zevenbergen & Thorno's Method를 3×3 moving windowing을 통해서 최대 경사방향과 경사를 구해서 충적층을 지나는 선구조 요소를 추출하고 다시 Hough 변환을 이용해서 1차 선구조를 추출하였다 이를 이용하여 충적층의 직각방향의 지형단면의 경사를 유추해서 spline 보간법을 이용해 단면의 최저점을 구하고 이 구해진 점들을 다시 Hough 변환을 이용해서 최종 선구조를 추출하였다. 본 연구에서 사용한 알고리즘은 기존 알고리즘에서 사용된 소창문보다 훨씬 큰 충적층이 분포하는 지역의 지형 경사가 수렴하는 부분에 선구조가 뚜렷이 나타남을 볼 수 있다. 최대경사방향과 경사를 구해서 얻어진 1 차선구조와 최종 선구조에서 선구조 방향이 다소 차이를 보인다. 1 차 선구조의 수직방향 지형단면의 자료를 이용함에 있어, 지형 단면의 시작정과 끝지점을 임의적으로 결정하는 것이 아니라, 충적층을 가로질러 최고점까지 또는 다음 충적층이 나을 때까지의 자료를 이용해서 보간법을 사용하였고, 충적층의 넓이에 따라 보간할 자료량의 차이에 의한 오차가 발생할 수 있다. 넓은 충적층에서 선구조가 잘 추출되는 반면에 좁은 충적층이 분포하거나 계곡에 해당하는 지역에l서는 경사수렴부와 일치하지 않는 선구조가 추출되었다. 이는 향후 계속적으로 연구해서 보완되어야 할 것으로 사료된다.페클 잡영 제거 정도에 있어 다른 필터들과 큰 차이가 없지만 경계선보존지수는 다른 필터들에 비하여 가장 우수함을 확인할 수 있었다.rbon 탐식효율을 조사한 결과 B, D 및 E 분획에서 유의적인 효과를 나타내었다. 이상의 결과를 종합해볼 때, ${\beta}$-glucan은 고용량일 때 직접적으로 또는 $IFN-{\gamma}$ 존재시에는 저용량에서도 복강 큰 포식세로를 활성화시킬 뿐 아니라, 탐식효율도 높임으로써 면역기능을 증진 시키는 것으로 나타났고, 그 효과는 crude ${\beta}$-glucan의 추출조건에 따라 달라지는 것을 알 수 있었다.eveloped. Design concepts and control methods of a new crane will be introduced in this paper.and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basi

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.5
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• pp.465-473
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• 2002

Images are easily corrupted by noise during the data transmission, data capture and data processing. A technical method of noise analyzing and adaptive filtering for reducing of quantum noise in radiography is presented. By adjusting the characteristics of the filter according to local statistics around each pixel of the image as moving windowing, it is possible to suppress noise sufficiently while preserve edge and other significant information required in reading. We have proposed adaptive weighted median(AWM) filters based on local statistics. We show two ways of realizing the AWM filters. One is a simple type of AWM filter, whose weights are given by a simple non-linear function of three local characteristics. The other is the AWM filter which is constructed by homogeneous factor(HF). Homogeneous factor(HF) from the quantum noise models that enables the filter to recognize the local structures of the image is introduced, and an algorithm for determining the HF fitted to the detection systems with various inner statistical properties is proposed. We show by the experimented that the performances of proposed method is superior to these of other filters and models in preserving small details and suppressing the noise at homogeneous region. The proposed algorithms were implemented by visual C++ language on a IBM-PC Pentium 550 for testing purposes, the effects and results of the noise filtering were proposed by comparing with images of the other existing filtering methods.

• Journal of Digital Convergence
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• v.18 no.4
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• pp.23-35
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• 2020

This study is based on prior research cases on workplace learning, which had a significant impact on corporate research. To improve problem solving and supplementing ability by keeping the opportunity to participate in workplace learning for the weak small business owners and to strengthen opportunities for practical growth, and to propose education, policy and institutional windowing. Therefore, to establish the relationship between small business owners' workplace learning, job satisfaction, and service quality, a research hypothesis was set in the background of prior research and empirical analysis was conducted. The results from 203 questionnaires were analyzed with SPSS 18.0 program. As an analytical result, first, workplace learning had a partial positive (+) impact on job satisfaction. Second, workplace learning had a partial positive (+) impact on service quality. Third, in the relationship between workplace learning and service quality, job satisfaction played a full mediating role. From this, it was found that formal learning, the subfactor of workplace learning did not have an impact on job satisfaction and service quality, as subtitle of educational environment including offsite training and self education, systematization, and structuralization depending on the poor environment of small enterprises. Therefore, it was found that small enterprises' poor environment was revealed from the managerial, economic and social perspectives and to compensate such defect, educational, policy, and institutional strategies to strengthen the opportunity for growth and development of small enterprises can be suggested to the governmental agencies or local governments. Despite the significant results of this study, there may be limitations. Therefore, further studies should be conducted in various fields with various samples in the future, and further studies should be conducted in academic and practical relationships that can improve the service quality and management performance.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.5
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• pp.993-1000
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• 2017

When the availability of embedded device is considered, combined countermeasure such as first-order masking and hiding countermeasures is quite attractive because the security and efficiency can be provided at the same time. Especially, combined countermeasure can be applied to the confusion and diffusion layers of the first and last rounds in order to provide the efficiency. Also, the middle rounds only employs first-order masking countermeasure or no countermeasure. In this paper, we suggest a novel side channel analysis with low complexity in the output of diffusion layer. In general, the attack target cannot be set to the output of diffusion layer owing to the high complexity. When the diffusion layer of block cipher is composed of AND operations, we show that the attack complexity can be reduced. Here, we consider that the main algorithm is SEED. Then, the attack complexity with $2^{32}$ can be reduced by $2^{16}$ according to the fact that the correlation between the combination of S-box outputs and that of the outputs of diffusion layer. Moreover, compared to the fact that the main target is the output of S-box in general, we demonstrate that the required number of traces can be reduced by 43~98% in terms of simulated traces. Additionally, we show that only 8,000 traces are enough to retrieve the correct key by suggested scheme, although it fails to reveal the correct key when performing the general approach on 100,000 traces in realistic device.

• Journal of KIISE:Information Networking
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• v.30 no.5
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• pp.656-667
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• 2003

Congestion control is a key task in reliable multicast along with error control. However, existing tree-based congestion control schemes such as MTCP and TRAMCC are designed for one-to-many reliable multicast and have some drawbacks when they are used for many-to-many reliable multicast. We propose an efficient congestion control mechanism, TMRCC, for tree-based many-to-many reliable multicast protocols. The proposed scheme is based on the congestion windowing mechanism and a rate controller is used in addition. The feedback for error recovery is exploited for congestion control as well to minimize the overhead at the receivers. The ACK timer and the NACK timers are set dynamically reflecting the network condition changes. The rate regulation algorithm in the proposed scheme is designed to help the flows sharing the same link to achieve the fair share quickly The performance of the proposed scheme is evaluated using ns-2. The simulation results show that the proposed scheme outperforms TRAMCC in terms of intra- session fairness and shows good level of responsiveness, TCP-friendliness, and scalability. In addition, we implemented the proposed scheme by integrating with GAM that is one of many-to-many reliable multicast protocols and evaluated the performance in a laboratory-wide testbed.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.131-139
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• 2023

In this study, we are purposed to find the educational effect of practical training using a 3D printed structure-based blind box on multidimensional radiographic image interpretation. The subjects were 83 (male: 49, female: 34) 2nd year radiological science students who participated in the digital medical imaging practice that was conducted for 3 years from 2020 to 2022. The learning method used 3D printing technology to print out the inside structure of the blind box designed by itself. After taking X-rays 3 times (x, y, z axis), the structure images in the blind box were analyzed for each small group. We made the 3D structure that was self-made with clay based on our 2D radiographic images. After taking X-rays of the 3D structure, it was compared whether it matches the structural image of the blind box. The educational effect for the practical training surveyed class faithfulness, radiographic image interpretation ability (attenuation concept, contrast concept, windowing concept, 3-dimensional reading ability), class satisfaction (interest, external recommendation, immersion) on a 5-point Likert scale as an anonymous student self-writing method. As a result, all evaluation items had high positive effects without significant differences between males and females. Practical education using blind boxes is a meaningful example of radiology education technology using 3D printing technology, and it is expected to be used as content to improve students' problem-solving skills and increase satisfaction with major subjects.

• Progress in Medical Physics
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• v.22 no.1
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• pp.35-41
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• 2011

For overall system test, hidden-target test have been used using film which leads to inherent analysis error. The purpose of our study is to quantify this error and to propose gel dosimeter based verification technique for 3-dimensional target point error. The phantom was made for simulation of human head and this has ability to equip 10 gel-dosimeter. $BANGkit^{TM}$ which we are able to manufacture whenever it is needed as well as to easily change the container with different shapes was used as a gel dosimeter. The 10 targets were divided into two groups based on shapes of areas with a planned 50% isodose line. All treatment and analysis was performed three times using Novalis and $BrainSCAN^{TM}$. The target point error is $0.77{\pm}0.15mm$ for 10 targets and directional target point error in each direction is $0.54{\pm}0.23mm$, $0.37{\pm}0.08mm$, $0.33{\pm}0.10mm$ in AP (anterior-posterior), LAT (lateral), and VERT (vertical) direction, respectively. The result of less than 1 mm shows that the treatment was performed through each precise step in treatment procedure. In conclusion, the 3-dimensional target point verification technique can be one of the techniques for overall system test.