• 한국해양공학회지
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• 제25권3호
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• pp.1-10
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• 2011

This paper estimates the residual longitudinal strength of a damaged double hull VLCC (Very Large Crude Carrier) under combined vertical and horizontal bending moments using Smith's method. The damage estimated in this study occurred due to collision or grounding accidents. The effects of the randomness of the yield stress, plate thickness, extent of damage, and the combination of these three parameters on the ultimate hull girder strength were investigated. Random variables were generated by a Monte Carlo simulation and applied to the double hull VLCC described by the ISSC (International Ship and Offshore Structures Congress) 2000 report.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2001년도 추계학술대회 학술발표 논문집
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• pp.279-282
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• 2001

This paper presents an image contrast enhancement technique for improving the low contrast images using the improved IAFC(Integrated Adaptive Fuzzy Clustering) Model. The low pictorial information of a low contrast image is due to the vagueness or fuzziness of the multivalued levels of brightness rather than randomness. Fuzzy image processing has three main stages, namely, image fuzzification, modification of membership values, and image defuzzification. Using a new model of automatic crossover point selection, optimal crossover point is selected automatically. The problem of crossover point selection can be considered as the two-category classification problem. The improved MEC can classify the image into two classes with unsupervised teaming rule. The proposed method is applied to some experimental images with 256 gray levels and the results are compared with those of the histogram equalization technique. We utilized the index of fuzziness as a measure of image quality. The results show that the proposed method is better than the histogram equalization technique.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.16-18
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• 2008

Because of being environmentally friendly, renewable energy resources has been growing at a high rate. Wind energy is one of the most successfully utilized of such sources for producing electrical energy. Due to the randomness of wind speed, wind farms can not supply power with a balanceable level as well as conventional power plants. The reliability evaluation of wind power is more and more important. Capacity credit is used to estimate the capacity credit of power systems including wind farms. This paper presents a method of capacity credit calculation for a power system considered wind farms and shows how it gets study on an actual power system (the Jeju Island power system). The paper describes the step of capacity credit calculation and presents test results, which indicate its effectiveness.

• 정보처리학회논문지D
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• 제10D권3호
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• pp.541-546
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• 2003

본 논문에서는 디지털 지문 이미지를 잡음원으로 하는 난수 생성기를 제안한다. 생체 정보를 잡음원으로 하는 난수 생성기는 아직까지 세계적으로 제안되지 않고 있다. 제안한 난수 생성기는 한 지문에 대하여 평균 9,334 비트를 0.03초에 생성하며, 생성된 비트 열은 NIST에서 권장한 16개의 난수성 통계 검증들을 모두 통과하였다.

• Journal of Electrical Engineering and Technology
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• 제4권4호
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• pp.485-491
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• 2009

The importance of renewable energy sources has been growing at a high rate as a result of being environment friendly. In particular, wind power is one of the most successfully utilized of such sources to produce electrical energy. Because of the randomness of wind speed, the reliability impact on this highly variable energy power is important aspect that needs to be assessed. In this paper, the impact on the reliability indices of wind speed correlation between two farms is considered.

• Environmental Engineering Research
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• 제14권1호
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• pp.26-31
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• 2009

Sorption of $Ni^{2+}$ in aqueous solution was studied using montmorillonite. The experimental and equilibrium data fitted well to the Langmuir isotherm model. From the kinetics data for nickel sorption onto montmorillonite, the diffusion of $Ni^{2+}$ inside the clay particles was the dorminant step controlling the sorption rate and as such more important for $Ni^{2+}$ sorption than the external mass transfer. $Ni^{2+}$ was sorbed due to strong interactions with the active sites of the sorbent and the sorption process tends to follow the pseudo second-order kinetics. Thermodynamic parameters (${\Delta}G^{\circ},\;{\Delta}H^{\circ},\;{\Delta}S^{\circ}$) indicated a non spontaneous and endothermic adsorption process while the positive low value of the entropy change suggests low randomness of the solid/solution interface during the uptake of $Ni^{2+}$ by montmorilionite. Heavy metals such as $Ni^{2+}$ in aqueous bodies can effectively be sorbed by montmorillonite.

• 패션비즈니스
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• 제12권4호
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• pp.131-142
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• 2008

One of the major fashion trends is the naturalism and ecology-conscious trend. The natural looks required in the trend require somewhat random distribution of yarn linear density, which results in irregular appearance along the yarn. This is a technically challenging work of producing yarns that look natural far from being artificial yet maintaining the intricately aesthetic randomness without causing process disturbances. This study focused on the characteristics of fabrics made of natural cellulosic fibers including hemp, ramie, flax, and polyester fabrics. Image analysis of the fabric samples included area measurement of yarn specimen, FFT and inverse FFT. Measurements of bending resistance, thickness, air permeability, and weight were also implemented to interpret the structural differences.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권10호
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• pp.3557-3571
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• 2014

We develop a secret key generation scheme using phase estimation in ultra-wideband (UWB) wireless fading channels. Based on the reciprocity theorem, two terminals extract the phase of the channel as a common random source to generate secret bits. Moreover, we study the secret key rate by a pair of nodes observing correlated sources and communicating to achieve secret key agreement over public communication channels. As our main results, we establish a more practical upper bound from Cramer-Rao bound (CRB) and compare it with a universally theoretical upper bound on the shared maximum key rate from mutual information of correlated random sources. Derivation and numerical examples are presented to demonstrate the bound. Simulation studies are also provided to validate feasibility and efficiency of the proposed scheme.

• Structural Engineering and Mechanics
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• 제62권3호
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• pp.259-272
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• 2017

In this study, recently developed swarm intelligence algorithm called Social Spider Optimization (SSO) approach and its enhanced version of SSO algorithm with spider jump techniques is used to develop a structural optimization technique for steel space structures. The improved version of SSO uses adaptive randomness probability in generating new solutions. The objective function of the design optimization problem is taken as the weight of a steel space structure. Constraints' functions are implemented from American Institute of Steel Construction-Load Resistance factor design (AISC-LRFD) and Ad Hoc Committee report and practice which cover strength, serviceability and geometric requirements. Three steel space structures are optimized using both standard SSO and SSO with spider jump (SSO_SJ) algorithms and the results are compared with those available in the literature in order to investigate the performance of the proposed algorithms.

• 한국멀티미디어학회논문지
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• 제5권6호
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• pp.665-673
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• 2002

본 논문에서는 LFSR(Linear Feedback Shift Register)의 대안으로 소개되고 있는 셀룰라 오토마타(CA: Cellular Automata)를 소개하고 이를 이용한 새로운 블록 암호 알고리즘을 제안한다. 제안된 블록 암호 알고리즘의 성능과 안전성 평가를 위해 쇄도효과와 수행속도에 대해 표준 블록 암호 알고리즘과 비교를 수행하고 또한 차분 분석법(Differential Cryptanalysis)에 대하여 제안 알고리즘에 대한 축소된 버전으로 평가를 수행한다. 부가적으로 제안 암호 알고리즘의 출력 비트열에 대하여 FIPS PUB 140-2(Federal Information Processing Standards publication 140-2)의 랜덤 수열에 대한 통계적 검정을 수행함으로써 출력 수열이 랜덤함을 보인다.