• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4A
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• pp.291-300
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• 2002

In this paper, a way of constituting optimized S box and G function was suggested in the block cipher whose structure is similar to SEED, which is KOREA standard of 128-bit block cipher. S box can be formed with nonlinear function and an affine transform. Nonlinear function must be strong with differential attack and linear attack, and it consists of an inverse number over GF(2$\^$8/) which has neither a fixed point, whose input and output are the same except 0 and 1, nor an opposite flexed number, whose output is one's complement of the input. Affine transform can be constituted so that the input/output correlation can be the lowest and there can be no fixed point or opposite fixed point. G function undergoes diffusive linear transform with 4 S-box outputs using the matrix of 4$\times$4 over GF(2$\^$8/). G function can be constituted so that MDS(Maximum Distance Separable) code can be formed, SAC(Strict Avalanche Criterion) can be met, there can be no weak input, where a fried point, an opposite fried point, and output can be two's complement of input, and the construction of hardware can be made easy. The S box and G function suggested in this paper can be used as a constituent of the block cipher with high security, in that they are strong with differential attack and linear attack with no weak input and they are excellent at diffusion.

• The Korean Journal of Food And Nutrition
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• v.26 no.3
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• pp.565-572
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• 2013

This study was performed to optimize the processing conditions and to select the optimum species for colored sweet potato chips (Shinjami, Juhwangmi and Hayanmi varieties) baked by far-infrared radiation. Sweet potato chips were prepared by different slicing thickness (1~3 mm), concentration of sucrose solution for soaking (15~30%), blanching time (15~60 sec), baking temperature ($110{\sim}140^{\circ}C$) and baking time (23~31 min) through sensory evaluation and failure stress measurement. Optimal processing condition of sweet potato chips using Shinjami was determined to 1 mm, 20%, 45 sec, $120^{\circ}C$ and 31 min, and those using Juhwangmi was determined as 1 mm, 25%, 45 sec, $130^{\circ}C$ and 29 min. Sweet potato chips using Hayanmi was determined as 1 mm, 20%, 45 sec, $120^{\circ}C$ and 31 min, respectively. Free sugar content of sweet potato chips was higher in chips than in raw materials. In the sensory evaluation, appearance, sweet taste, hardness, and overall acceptance were higher in Juhwangmi than in the Shinjami and Hayanmi varieties. Overall acceptance, sugar content, b-value and failure stress were highly correlated among factors affecting the sensory characteristics (p<0.01). From the results of this study, Juhwangmi variety was selected for production of sweet potato chips.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.443-450
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• 2009

Purpose: Conventional image reconstruction uses simplified physical models of projection. However, real physics, for example 3D reconstruction, takes too long time to process all the data in clinic and is unable in a common reconstruction machine because of the large memory for complex physical models. We suggest the realistic distributed memory model of fast-reconstruction using parallel processing on personal computers to enable large-scale technologies. Materials and Methods: The preliminary tests for the possibility on virtual manchines and various performance test on commercial super computer, Tachyon were performed. Expectation maximization algorithm with common 2D projection and realistic 3D line of response were tested. Since the process time was getting slower (max 6 times) after a certain iteration, optimization for compiler was performed to maximize the efficiency of parallelization. Results: Parallel processing of a program on multiple computers was available on Linux with MPICH and NFS. We verified that differences between parallel processed image and single processed image at the same iterations were under the significant digits of floating point number, about 6 bit. Double processors showed good efficiency (1.96 times) of parallel computing. Delay phenomenon was solved by vectorization method using SSE. Conclusion: Through the study, realistic parallel computing system in clinic was established to be able to reconstruct by plenty of memory using the realistic physical models which was impossible to simplify.

• Journal of Korea Water Resources Association
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• v.34 no.4
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• pp.303-316
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• 2001

In this study, Radial Basis Function(RBF) Neural Networks Model, a kind of Hybrid Neural Networks was applied to hydrological forecasting in a small watershed. RBF Neural Networks Model has four kinds of parameters in it and consists of unsupervised and supervised training patterns. And Gaussian Kernel Function(GKF) was used among many kinds of Radial Basis Functions(RBFs). K-Means clustering algorithm was applied to optimize centers and widths which ate the parameters of GKF. The parameters of RBF Neural Networks Model such as centers, widths weights and biases were determined by the training procedures of RBF Neural Networks Model. And, with these parameters the validation procedures of RBF Neural Networks Model were carried out. RBF Neural Networks Model was applied to Wi-Stream basin which is one of the IHP Representative basins in South Korea. 10 rainfall events were selected for training and validation of RBF Neural Networks Model. The results of RBF Neural Networks Model were compared with those of Elman Neural Networks(ENN) Model. ENN Model is composed of One Step Secant BackPropagation(OSSBP) and Resilient BackPropagation(RBP) algorithms. RBF Neural Networks shows better results than ENN Model. RBF Neural Networks Model spent less time for the training of model and can be easily used by the hydrologists with little background knowledge of RBF Neural Networks Model.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1474-1478
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• 2007

수문 및 수질자료는 일정한 기준에 의한 관측치를 시계열 자료로 기록하거나 전송할 때 다양한 형태의 오차가 발생하게 되며 또한 수문 및 수질자료를 관측하는 측정기기의 고장과 유지관리 등의 어려움으로 다양한 형태의 결측 자료가 발생하고 있다. 이와 더불어 수문 및 수질자료는 시공간적 변동성이 크며 비선형성이 강한 특성을 갖고 있다. 이러한 수문 및 수질 자료를 이용하여 모형을 구축할 경우 다양한 형태의 잡음에 대한 검증 및 잡음저감이 필수적 요건이라 할 수 있다. 따라서 본 연구에서는 영산강 유역의 본류부를 대표하는 나주지점에 대한 유출량과 총유기탄소(TOC) 농도 및 TOC 부하량 예측모형을 개발하였으며, 이를 위한 방법으로는 잡음저감을 위하여 웨이블렛 변환과 인공신경망을 적용하였다. TOC 부하량 자료는 유출량과 TOC 자료간의 함수로서 표현이 가능함에 따라 유출량 및 TOC 자료가 결측되었을 경우 역함수에 의한 계산으로 결측 자료에 대한 보간이 가능하다. 따라서 본 연구의 주안점은 잠음 저감 및 인공신경망에 의해 최적화된 예측 모형이 결측된 유출량과 TOC 자료에 대한 역함수로 정도있는 유출량과 TOC 자료 생성 가능성을 검토하고자 한다. 본 연구의 적용 결과, 유출량 자료가 결측되었을 경우 TOC 및 TOC 부하량 예측으로 유출량 자료에 대한 간접추정 및 결측 자료에 대한 보간의 정도를 평가한 결과 $R^2$는 0.99 이상의 값을 보였다. 또한, TOC 자료가 결측되었을 경우 역시 $R^2$는 비교적 우수한 0.97 이상의 값을 보였다. 따라서 본 연구에서 개발한 유출량 및 TOC, TOC 부하량 예측모형의 개발은 정도있는 유출량 및 TOC 수질 자료의 생성이 가능할 것으로 기대된다.한 물순환 해석을 할 수 있는 기반을 확보 하였으며, 가용한 장 단기간의 관측자료와 물수지 분석 연산식의 추정치를 바탕으로 관측자료에 의한 물수지 분석을 수행하였다. 분석 결과로 산지 소하천 유역인 설마천 시험유역의 각 수문요소의 물이동간의 정량적인 값을 알 수가 있었으며, 앞으로 추가적이고 지속적인 수문모니터링이 운영되고 물순환 해석 모형에 의한 검증이 수행된다면 정량적인 물순환 관계를 규명할 수 있을 뿐만 아니라 이와 관련된 수문요소기술을 확보할 수 있을 것이다.절한 타협과 조정을 필요로 한다. 그러나 절제의 한계를 넘어선다고 생각되거나, 조정의 노력이 불가능하거나, 실패했을 때 폭력적인 행동으로 나타나게 된다. 리차즈(I.A Richards)는 분노와 공포는 일단 겉잡을 수 없는 경향이 있다고 하면서 오늘날 폭력에 대한 요구가 일상의 정서 생활에 있어, 억압을 통한, 빈곤함을 반영하고 있지 않은지 생각해봐야 할 것이라고 충고한다. 조성 가이드라인(안)을 제시하였다.EX>$\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와의 비교를 해보면 상 중 하품의 통합 9개소가 삭제되어 있고, $\ulcorner$동국여지승람$\lrcorner$(東國與地勝覽) 에서는 자기소와 도기소의 위치가 완전히 삭제되어 있다. 이러한 현상은 첫째, 15세기 중엽 경제적 태평과 함께 백자의 수요 생산이 증가하자 군신의 변별(辨別)과 사치를 이유로 강력하게 규제하여 백자의 확대와 발전에 걸림돌이 되었다. 둘째, 동기(銅器)의 대체품으로 자기를 만들어 충당해야할 강제성 당위성 상실로 인한 자기수요 감

• Korean Journal of Digital Imaging in Medicine
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• v.6 no.1
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• pp.24-30
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• 2003

Flat-panel detector(FPD) is the driving force for realizing the next gene ration of x-ray system. In this study, we developed amorphous selenium(a-Se) based flat-panel digital X-ray detector(DXD) for radiography. The prototype detector consists of an amorphous selenium layer and a thin-film transistor(TFT) array. Comparing to other papers1)-4), optimization of amorphous selenium and progress of evaporation were similar. The pixel pitch of fabricated detector was $139{\mu}m$, fill factor was 86%, and the size was 14"${\times}$8.5". Hand and test bar pattern images were acquired. A high modulation transfer function(MTF) factor was obtained: 58% at 3.0 lp/mm.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.4
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• pp.247-259
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• 2007

In this study, we examined the flux of carbon and water using an eco-hydrological model, Regional Hydro-Ecologic Simulation System (RHESSys). Our purposes were to develop a set of parameters optimized for a well-designed experimental watershed (Gwangneung Research Watershed, GN) and then, to test suitability of the parameters for predicting carbon and water fluxes of other watershed with different regimes of climate, topography, and vegetation structure (i.e Gangseonry Watershed in Mt. Jumbong, GS). Field datasets of stream flow, soil water content (SWC), and wood biomass product (WBP) were utilized for model parameterization and validation. After laborious parameterization processes, RHESSys was validated with the field observations from the GN watershed. The parameter set identified at the GN watershed was then applied to the GS watershed in Mt. Jumbong, which resulted in good agreement for SWC but poor predictability for WBP. Our study showed that RHESSys simulated reliable SWC at the GS by adjusting site-specific porosity only. In contrast, vegetation productivity would require more rigorous site-specific parameterization and hence, further study is necessary to identify primary field ecophysiological variables for enhancing model parameterization and application to multiple watersheds.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.1
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• pp.1-17
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• 2020

Three-dimensional microscopic approaches in histopathology display multiplex properties that present puzzling questions for specimens as related to their comprehensive volumetric information. This information includes spatial distribution of molecules, three-dimensional co-localization, structural formation and whole data set that cannot be determined by two-dimensional section slides due to the inevitable loss of spatial information. Advancement of optical instruments such as two-photon microscopy and high performance objectives with motorized correction collars have narrowed the gap between optical theories and the actual reality of deep tissue imaging. However, the benefits gained by a prolonged working distance, two-photon laser and optimized beam alignment are inevitably diminished because of the light scattering phenomenon that is deeply related to the refractive index mismatch between each cellular component and the surrounding medium. From the first approaches with simple crude refractive index matching techniques to the recent cutting-edge integrated tissue clearing methods, an achievement of transparency without morphological denaturation and eradication of natural and fixation-induced nonspecific autofluorescence out of real signal are key factors to determine the perfection of tissue clearing and the immunofluorescent staining for high contrast images. When performing integrated laboratory workflow of tissue for processing frozen and formalin-fixed tissues, clear lipid-exchanged acrylamide-hybridized rigid imaging/immunostaining/in situ hybridization-compatible tissue hydrogel (CLARITY), an equipment-based tissue clearing method, is compatible with routine procedures in a histopathology laboratory.

• Journal of Food Hygiene and Safety
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• v.31 no.4
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• pp.304-309
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• 2016

This study was assessed stability of ethanolic extract from Cirsium setidens Nakai that will be applied for development of functional foods and ingredients. We evaluated pectolinarin content, total phenol content and antioxidant activity (DPPH radical scavenging activity and FRAP assay) of ethanolic extract from C. setidens Nakai against various temperature (4, 25 and $50^{\circ}C$) and pH (4.0, 7.0 and 10.0). Our results show that the pectolinarin and total phenol contents in ethanolic extract from Cirsium setidens Nakai slightly reduced during the storage periods. Moreover, the DPPH radical scavenging activity at $4^{\circ}C$ was higher than those of other temperature. Pectolinarin content, total phenol content and DPPH radical scavenging activity of ethanolic extract from Cirsium setidens Nakai at acidic (pH 4.0) and neutral (pH 7.0) pH ranges were higher than at alkaline pH ranges. These results indicate that the optimum storage condition of C. setidens Nakai ethanol extract are temperature $4^{\circ}C$ and pH 4.0-7.0 ranges.

• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.575-580
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• 2020

In this study, we simulated an amine regeneration process with heat-stable salts removal unit. We derived the optimal operating conditions considering the flow rate of waste, the removal rate of heat-stable salts, and the loss rate of MDEA (methyl diethanolamine). In the amine regeneration process that absorbs and removes acid gas, heat-stable salt impairs the absorption efficiency of process equipment and amine solution. An ion exchange resin method is to remove heat-stable salts through neutralization by using a strong base solution such as NaOH. The acid gas removal process was established using the Radfrac model, and the equilibrium constant of the reaction was calculated using Gibbs free energy. The removed amine solution is separated and flows to the heat-stable salts remover which is modeled by using the Rstoic model with neutralization reaction. Actual operation data and simulation results were compared and verified, and also a case study was conducted by adjusting the inflow mass of removal unit followed by suggesting optimal conditions.