• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.3
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• pp.49-52
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• 2001

The derivatives of spironaphthooxazine gause photoisomerization when they are illuminate with UV light. We investigated the photoisomerization of spironaphthooxazine derivatives for holographic memory. Langmuir-Blodgett (LB) films contain amphiphile spironaphthooxazine derivatives which can be applied in molecular devices by a change of molecular level energy and a refractive index. In order to investigate the photoisomerization of spironaphthooxazine derivatives at the air/water energy and a refractive index. In order to investigate the photoisomerization of spironaphthooxazine derivatives at the air/water interfaces, spironaphthooxazine derivatives with side alkyl chains were synthesized. The films of the spironaphthooxazine derivatives were characterized by the measurement of UV/vis spectroscopy, Brewster Angle Microscopy (BAM) and Atomic Force Microscopy (AFM). The monolayers of the spironaphthooxazine derivatives mixed with stearic acid were stable at the air/water interface and visualized by the measurement of BAM. The spironaphthooxazine derivative monolayers on the glass surface showed the maximum efficiency of diffraction as 0.99% by the measurement of holography.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.68-77
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• 2018

Regarding demand response (DR) by residential users (R-users), the users try to reduce electricity costs by adjusting their power consumption in response to the time-varying price. However, their power consumption may be affected not only by the price, but also by user convenience for using appliances. This paper proposes a methodology for appliance scheduling (AS) that considers the user convenience based on historical data. The usage pattern for appliances is first modeled applying the copula function or clustering method to evaluate user convenience. As the modeling results, the comfort distribution or representative scenarios are obtained, and then used to formulate a discomfort index (DI) to assess the degree of the user convenience. An AS optimization problem is formulated in terms of cost and DI. In the case study, various AS tasks are performed depending on the weights for cost and DI. The results show that user convenience has significant impacts on AS. The proposed methodology can contribute to induce more DR participation from R-users by reflecting properly user convenience to AS problem.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.6_spc
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• pp.674-679
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• 2016

According to the conventional studies on the noise and cardiovascular effect, railway noise is better associated with hypertension and adverse cardiovascular events than road traffic noise. But the underlying mechanisms remain unclear. We investigated the hypothesis that exposure to acute railway noise would the unfavorable effect of cardiovascular and autonomic system in healthy young subjects. Using a randomized, sham-controlled cross-over design, ten subjects were assigned to receive either an exposure to high speed train noise (84 dB) for 30 minutes or a control condition (non noise), separated by two days. Blood pressure, heart rate, augmentation index and heart rate variability as indices of cardiovascular and autonomic system function were measured at baseline, during, and recovery from two trials. The results show that exposure to acute railway noise significantly increased diastolic blood pressure and augmentation index, which may cause of adverse cardiovascular effects.

• Journal of Nutrition and Health
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• v.22 no.4
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• pp.275-289
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• 1989

The purpose of this study is to develop a computer system with data file and computerized programs for nutrition counseling. In this research, a 16 / XT personal computer (word : COBOL) compatible with IBM-PC/XT was used. Computer system developed for this study was as follows: Data files(food composition list, food exchange list, nutrition management comment, special diet therapy) were used for analysis the nutritional status and the ntrition education comment. (1) Programs for the nutritional status assessment 1) General information a) Name, age, sex, higher, weight, activity, disease and special diet b) Ideal body weight and Obesity assessment(Kaup index and Broca index) c) Rest and athletics status d) Biochemical data comparision with standard 2) Food Intakes 3) Nutrient Intakes a) Comparison of the amounts intaked with the recommended dietary allowances for present weight. b) Comparison of the energy composition rate intaked with the recommended dietary allowances for present weight. b) Comparison of the energy composition rate intaked with the recommended for present weight and ideal weight. c) Nutrient analysis by each meal and snack. 4) Food intakes from each food group and comparison with recommended 5) Special nutrient analysis. (2) Programs for the nutrition education based on nutritional status assessment. 1) Suggestion of number of food exchange group 2) Nutritional assessment and advise comments 3) Nutritional management comments 4) Special diet therapy In the study, the nutritioal status and nutrition education comments are based on individual data from nutrition counseling.

• Computers and Concrete
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• v.22 no.6
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• pp.539-550
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• 2018

Concrete is highly non-linear material which is originating from the transition zone in the form of micro-cracks, governs material response under various loadings. In this paper, the constitutive models published by many researchers have been used to generate novel stiffness parameters and constitutive curves for concrete. Following such linear material formulations, where the energy is conservative during the curvature, and a nonlinear contribution to the concrete has been made and investigated. In which, nonlinear concrete elastic modulus modeling has been developed that is capable-of representing concrete elasticity for grades ranging from 10 to 140 MPa. Thus, covering the grades range of concrete up to the ultra-high strength concrete, and replacing many concrete models that are valid for narrow ranges of concrete strength grades. This has been followed by the introduction of the nonlinear Hooke's law for the concrete material through the replacement of the Young constant modulus with the nonlinear modulus. In addition, the concept of concrete elasticity index (${\varphi}$) has been proposed and this factor has been introduced to account for the degradation of concrete stiffness in compression under increased loading as well as the multi-stages micro-cracking behavior of concrete under uniaxial compression. Finally, a sub-routine artificial neural network model has been developed to capture the concrete behavior that has been introduced to facilitate the prediction of concrete properties under increased loading.

• Journal of Korean Association for Spatial Structures
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• v.19 no.2
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• pp.101-108
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• 2019

In this paper, the characteristic of intrinsic mode function(IMF) and its orthogonalization of ensemble empirical mode decomposition(EEMD), which is often used in the analysis of the non-linear or non-stationary signal, has been studied. In the decomposition process, the orthogonal IMF of EEMD was obtained by applying the Gram-Schmidt(G-S) orthogonalization method, and was compared with the IMF of orthogonal EMD(OEMD). Two signals for comparison analysis are adopted as the analytical test function and El Centro seismic wave. These target signals were compared by calculating the index of orthogonality(IO) and the spectral energy of the IMF. As a result of the analysis, an IMF with a high IO was obtained by GSO method, and the orthogonal EEMD using white noise was decomposed into orthogonal IMF with energy closer to the original signal than conventional OEMD.

• Journal of the Korean Solar Energy Society
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• v.39 no.4
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• pp.11-24
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• 2019

The total solar irradiation on horizontal surfaces is separated into the beam and diffuses components. Although horizontal global irradiance is a commonly measured parameter for many sites, horizontal diffuse irradiance is not so readily obtainable. For such sites that measure global irradiation alone, a simple but reasonably accurate method is required to estimate diffuse irradiance from its global counterpart. This study investigates the applicability of correlation coefficients models correlating hourly diffuse and beam fraction and hourly clearness index in Daejeon. The three diffuse to global correlation coefficients models (Orgill and Holland model, CIBSE Guide J model, and Erbs et al. model) are selected and the three modified beam to global correlation coefficients models are generated. MBE, RMSE, r-squared of Daejeon and Daejeon boundary site-fitted models are compared with the case of original coefficients. The comparison result shows that the beam and diffuse to global solar irradiation correlation coefficients models with boundary site-fitted coefficients are best suitable for Daejeon. Further researches will be conducted to find the boundary site-fitting method using measured data of other cities and correlation coefficients models using solar altitude, cloud cover, and sunshine duration.

• Nuclear Engineering and Technology
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• v.51 no.2
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• pp.561-572
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• 2019

In the design criterion for the nuclear power plant piping system, the limit state of the piping against an earthquake is assumed to be plastic collapse. The failure of a common piping system, however, means the leakage caused by the cracks. Therefore, for the seismic fragility analysis of a nuclear power plant, a method capable of quantitatively expressing the failure of an actual piping system is required. In this study, it was conducted to propose a quantitative failure criterion for piping system, which is required for the seismic fragility analysis of nuclear power plants against critical accidents. The in-plane cyclic loading test was conducted to propose a quantitative failure criterion for steel pipe elbows in the nuclear power plant piping system. Nonlinear analysis was conducted using a finite element model, and the results were compared with the test results to verify the effectiveness of the finite element model. The collapse load point derived from the experiment and analysis results and the damage index based on the stress-strain relationship were defined as failure criteria, and seismic fragility analysis was conducted for the piping system of the BNL (Brookhaven National Laboratory) - NRC (Nuclear Regulatory Commission) benchmark model.

• Current Optics and Photonics
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• v.3 no.2
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• pp.143-149
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• 2019

Shape ellipticity dependence of the exciton fine energy levels in CdTe and CdSe nanocrystal quantum dots were compared theoretically by considering the crystal structure and the Coulomb interaction of an electron and a hole. While quantum dot ellipticity changes from an oblate to prolate quantum dot via spherical shape, both the fine energy levels and the dipole moment in wurtzite structure of a CdSe quantum dot change linearly for ellipticity. In contrast, CdTe quantum dots were found to show a level crossing between the bright and dark exciton states with a significant change of the dipole moment due to the cubic structure. Shape ellipticity dependence of the optical nonlinearities in CdTe and CdSe nanocrystal quantum dots was also calculated by using semiconductor Bloch equations. For a spherical shape quantum dot, only $1^L$ dominates the optical nonlinearities in a CdSe quantum dot, but both $1^U$ and $0^U$ contribute in a CdTe quantum dot. As excitation pulse area becomes strong (${\sim}{\pi}$), the optical nonlinearities of both CdSe and CdTe quantum dots are mainly governed by absorption saturation. However, in the case of a prolate CdTe quantum dot, the real part of the nonlinear refractive index becomes relatively significant.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.65-65
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• 2017

상수관망 시스템(Water Distribution System, WDS)은 원활한 용수 공급을 위해 구축된 사회기반시설물로써, 물 공급절차에 따라 그 구성요소를 공급원, 공급 경로, 수요지 등의 범주로 구분할 수 있다. 원활한 물 공급이란 수요지에서 요구하는 수량과 압력 수준을 충족시키는 것을 의미하며, 따라서 상수관망의 용수공급능력은 요구 수량 및 압력과 실제 공급 결과를 비교함으로써 가늠할 수 있다. 과거에는 두 가지 기준을 별도로 산정하여 이를 평가하였으나, 유량과 압력을 함께 고려할 수 있는 에너지 기반의 평가 방법이 제시되면서 시스템 내 에너지 분포를 정량화하여 시스템의 용수공급능력을 평가하는 연구가 주목받고 있다. 세계적으로 많은 연구자들은 시스템 내 에너지 흐름 상태를 정량화함으로써 다양한 형태의 상수관망의 신뢰도지수(Reliability Index)를 제안한 바 있다. 이 때, 대부분의 신뢰도 지수 연구에서는 수요지에 공급된 에너지를 기본적으로 유지해야 하는 최소요구 에너지(Required Energy)와 비상 상황에 대응하기 위한 잉여 에너지(Surplus Energy)로 구분하고 있으며, 잉여 에너지를 상수관망의 공급 안정성을 나타내는 핵심 요소로 활용하고 있다. 확보된 잉여 에너지는 비상시 최소요구 에너지를 대체하는 개념에서 복원력으로 표현되어, 잘 알려진 Resilience Index(RI)를 비롯해 많은 복원력 지수가 존재한다. 본 연구에서는 복원력 지수를 포함한 세 가지의 신뢰도 지수를 적용하여 상수관망의 용수공급 상황 변화에 따른 시스템의 안정성을 분석하였다. 특히, 절점별 복원력 지수를 산정하고 그 분포를 공간적으로 도시하여 파악함으로써, 비상시 효율적인 운영을 위한 판단기준으로써 신뢰도 지수를 폭 넓게 활용할 수 있음을 제시하였다.