• The Journal of Engineering Geology
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• v.33 no.1
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• pp.137-149
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• 2023

In order to intuitively grasp the earth pressure direction acting on the structure and displacement state, displacement data in the horizontal and vertical directions were processed using the sigmoid function. A displacement coordinate system was set up for each axis. The system can intuitively check the current displacement and assess the management stage of each point. A displacement path can be compiled from continuously recorded points, allowing trends in the displacement's history and stress direction to be known. Analysis of data measured for excavated ground, found that displacement occurred in the direction of destressing at all points, and that the points' management state steady. Similar behavior trends were found among measurement points with high spatial correlation, whereas differing behavior trends occurred among measurement points with low spatial correlation. If the correlation analysis of the precursor and behavior area is performed using the continuously distributed surface settlement data and displacement coordinate system, it will be possible to predict the failure time and area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.91-102
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• 2020

This study constructed production frontiers of inputs and outputs in a sequential manner, measured inefficiencies by applying a non-radial sequential weighted Russell directional distance function to these frontiers, and analyzed Luenberg productivity indices and the contribution of each of input and output factor based on these distances. The results are as follows. First, the productivity of banks increased due to technical changes after the global financial crisis. Second, productivity growth decreased between 2009 and 2014 due to technical changes after the recession, as previous studies have shown that technology progressed before the global financial crisis but then largely decreased or remained the same thereafter. After 2014, the productivity of banks improved. This result may be due to both technology improvement after 10 years of stagnation and reduction of inputs and non-performing loans. Third, the 3.6% annual of productivity growth for 10 years was comprised of 1.77% household loans, 0.67% corporate loans, 0.98% manpower, 1.18% non-performing loans, -0.5% total deposits, and -1.25% securities. Finally, this study has limitations since it could not control risks such as capital structure and interest volatility.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.3
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• pp.227-235
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• 2012

The void distribution in concrete materials strongly affects its material properties. Therefore, the identification of spatial distribution of void is important to understand and estimate material behavior. To examine and quantify the void distribution inside lightweight aggregates, CT(computed tomography) image is used. 3D lightweight aggregate images are generated by stacking of cross-sectional images from CT. Spatial distribution of void of aggregate along the direction is visualized on the sphere using probability distribution function. Stiffness of lightweight aggregate for the directions is also examined. It is confirmed that direction-based probability distribution and stiffness from CT images are effective in characterizing void distributions of aggregates.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.2091-2096
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• 2013

This paper present a method of efficiency circuit design based on directed graph which was represented by tree structure relationship between input and output of nodes. In this paper, we introduce the concept of mathematical analysis based on tree structure which was designed by optimal localized computable circuit. Using the proposed circuit design algorithms in this paper, it is possible to design circuit which directed tree graph have any node number. The proposed method is more effective, regularity and extensibility than former method.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.79.1-79.1
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• 2010

세종 산개성단 탐사관측 연구의 일환으로 중년 산개성단 NGC 2353에 대한 UBVI CCD 측광을 수행하였다. 측광학적인 방법으로 성단 내의 구성원을 선정하였으며, 이로부터 이 성단의 성간소광과 거리를 각각 E(B-V)=$0.10\pm0.02mag$와 $d=1.17\pm0.04\;kpc$으로 얻었다. 성단 구성원의 공간적인 분포를 통해서 성단의 형태가 북서 방향에서 남동 방향을 잇는 축을 중심으로 타원의 형태를 띠고 있는 것을 발견하였다. Padova 그룹이 제시한 이론적인 등연령 곡선을 관측한 색등급도에 맞춤으로써 이 성단의 나이를 1억 3천만년으로 추정하였으며, 이는 기존 연구보다 나이가 많은 것으로 나타났다. 구성원의 거리지수 분포에서 이 성단의 거리지수보다 밝은 곳에 나타나는 쌍성의 분포를 Gaussian 분포와 맞추어 $46\pm4%$ 정도의 최소 쌍성비율을 추정하였다. 마지막으로 광도함수와 질량함수를 유도하였고, 질량함수의 기울기는 $\Gamma=-1.4\pm0.2$를 얻었다.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.1
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• pp.53-62
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• 2001

In this paper, the hybrid function by local scale control is proposed to detect the optimal edges from blurred images. In the case of image capturing, some blurring is occurred by the characteristics of the illumination and the reflected light. During processing the blurred image, it is difficult to detect perfect edges. This algorithm proposed a new hybrid function which is merged Gaussian function and the second derivative of Gaussian function. And it detects the optimal edges applying directional edge detection by Canny algorithm as the scale factor of $\sigma$ in the given local mask has been changed after convolving the hybrid function for input image. In the result, the performance is confirmed that this algorithm is better than Sobel, Robert and Canny edge detector by analyzing the some test images. And the results is obtained 0.2 ㏈ ~ 14 ㏈ of PSNR than those conventional method.

• Journal of Internet Computing and Services
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• v.12 no.6
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• pp.139-147
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• 2011

We proposed the secure and efficient passive RFID protocol which is based on one-way hash based low-cost authentication protocol (OHLCAP). The paper introduces OHLCAP and the vulnerabilities of OHLCAP and suggests security solutions by analyzing them. Afterwards, The paper presents the proposed protocol and demonstrates computational performance and security of the protocol. This protocol not only has the resistances against eavesdropping attack, impersonation attack, desynchronization attack, and replay attack but also provides untraceability and forward secrecy.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.2
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• pp.81-94
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• 2012

On December 11, 2001, China joined the WTO and became one of the member countries and the Chinese financial markets had to be open in 5 years. So, the Chinese government transformed national commercial banks into joint-stock banks. The purpose of this paper is to investigate the validity of this decision by the Chinese government. In order to measure the efficiency of banks, the directional distance function (DDF) methodology is used, which analyzes whether a bad output exists in the outputs. In the empirical analysis, the number of staffs, the fixed assets, and the equity capital are used as inputs, while the loans and the non-performing loans ratio are used as a good output and a bad output, respectively. The non-performing loans ratio is included in output since it could affect the efficiency of banks. If it isn't considered in the analysis, a distortion might occur in analyzing the efficiency of banks. The results show that the efficiency of the major commercial banks was improved, and that the efficiency of joint-stocks banks was higher for 2002-2003 while the efficiency of national commercial banks was higher for 2004-2006. It was due mainly to the foreign exchanges reserve funds injected into national commercial banks by the Chinese Ministry of Finance, and as a result bad assets were eliminated.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.6
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• pp.542-547
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• 2000

진화프로그래밍(Evolutionary Programming : EP)은 최적화 문제에 있어서 매우 유용한 기법으로 자연선택의 원리를 모방한 탐색알고리즘이다. EP는 기존의 최적화 알고리즘에 비하여 여러해를 동시에 탐색하는 전역탐색(global search)방법이므로 국부수렴(local convergence)의 가능성이 줄어들고, 최적화 파라메터 영역의 연속성과 미분치의 존재성과 같은 조건이 필요 없는 장점을 갖는다. 이러한 장점에도 불구하고, EP의 탐색영역이 초기조건 및 최적화 파라메터들의 랜덤 생성 그리고 최적화에 필요한 전략적 파라메터들에 의하여 탐색 영역이 결정되고, 수렴성이 느린 단점을 갖는다. 이러한 문제를 해결하기 위하여, 본 연구에서는 빠른 수렴성과 다양성을 갖는 개선된 EP을 제안하고, 제안된 방향성 벡터를 갖는 개선된 EP를 함수 최적화 문제에 적용하여 그 성능의 유용성을 보이고자 한다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.4
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• pp.244-252
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• 2014

EOF (Empirical Orthogonal Function) analysis is applied to investigate the sand movement in Hujeong Beach. For the analysis, the profile data which were observed five times from June 2009 to May 2010 along the 13 baselines were used. To secure the temporal and physical consistency among the 13 profile data, the 13 profile data were combined into one data and using this data the EOF analysis was performed. According to the analysis, the first EOF is related with the mean topography and the second EOF represents the natural variation of sediment migration and the third EOF is related with the along-shore sediment transport arising from storm. The remaining EOFs show no special relation with wave conditions. In conclusion the main factors which are having great effects on Hujeong Beach's sand movement are analyzed as natural variation and along-shore sediment transport owing the wave conditions.