• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.453-462
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• 1994

Variation of seismic wave field in a multi-layered attenuating elastic half space is studied by the propagator matrix method and point source models of which fault-slip functions are defined as ramp functions. In this paper, the earth is modeled as being composed of horizontally stratified layers, with uniform material properties for each layer. The partial differential equations for the seismic motion in each layer are solved using a Fourier Hankel transform approach. Time histories and frequency contents of accelerations and displacements due to a vertical dip-slip and strike-slip point source located in the underlain half space are calculated at the layer interfaces using the developed programs and their characteristics are represented.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.301-310
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• 2006

A series of laboratory tests was carried out for analyzing compaction characteristics of hydraulic fill soils(or hydraulically filled soils). Hydraulic fill soils were settled down by the weight of soil particle itself in water and consolidated by the extraction of water from the soil structures. Water content and dry unit weight were observed as the depth of sedimentation and consolidation soil. It was found from the result that the optimum water content $(W_{cpt})$ of the maximum unit weight$(\gamma_{dmax})$ is higher than that of laboratory compaction test(KS F 2312 A method). It was due to difference in compaction energy and compaction effect between two methods. And the maximum dry unit of hydraulic fill soil is smaller than that of laboratory compaction test. Especially in terms of compaction effect, the maximum relative compaction degrees$(R_{cmax})$ of Seamangum dredged sand, river sand and mixed sand, half and half of dredged and river sands, were 85%, 91% and 86%, respectively. It means that the compaction effect can be $85\sim91%$ of the maximum unit weight in laboratory compaction test.

• ALGAE
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• v.21 no.1
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• pp.133-139
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• 2006

Outdoor cultivation of cyanobacterium Spirulina platensis was carried out for 40 days in a batch mode. A half concentration of the SOT based on the underground water was used as culture medium. Working volume was 5.7 tons with 0.2 m depth. During cultivation, mean water temperature, DO and light intensity were all in proper conditions for the S. platensis growth. The adjustment of pH to over 10 with Na2CO3 and addition of the 1.5% natural salt were very effective to delete contaminant organisms, Chlamydomonas moewusii and Chlorella minutissima occurred one after the other in the culture. The mean productivity of the biomass based on the dry cell weight from 14 to 25 days, after the contaminants were deleted, was 7.8 g ·m–2· d–1, which was relatively high productivity in that a half concentration of the SOT was used for the culture. Underground water used in the culture minimized contaminants invasion and addition of the 1.5% natural salt was effective to delete contaminants as well as acted as mineral supplement in outdoor cultivation of S. platensis. Harvesting using the floating activity of S. platensis was effective from mass floating in day time after overnight without agitation and illumination.

• Design & Manufacturing
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• v.2 no.3
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• pp.40-44
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• 2008

Shaving in sheet metal forming is defined as a finish process to make the sheared surface clean which was blanked or pierced in the previous shearing stage. In this study the new shaving technique is applied to the progressive operation. The specimen is automatically fed by continuous movement of the strip. Which improve the positioning accuracy higher. For this study a square part which consist of blanking and piercing is selected for investigation and the progressive die which includes pre-piercing, pierce-shaving, half-blanking and blank-shaving etc is prepared for specimens of steel sheet(SPCC) and aluminum alloy sheet(AL5052). Experiments are carried out for several working variables such as shaving allowance, pre-shearing clearance and relative half-blanking depth. Consequently it was confirmed that the shaving by progressive die can be successfully employed to produce the clean parts requiring shaving process and optimum working conditions for shaving SPCC and AL5052 sheet metal are shaving allowance of 0.2mm(1.3% of thickness) and pre-shearing clearance of 5%.

• Computational Structural Engineering : An International Journal
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• v.2 no.1
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• pp.33-42
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• 2002

A computationally efficient stiffness design method for building structures is proposed in which dynamic soil-structure interaction based on the wave-propagation theory is taken into account. A sway-rocking shear building model with appropriate ground impedances derived from the cone models due to Meek and Wolf (1994) is used as a simplified design model. Two representative models, i.e. a structure on a homogeneous half-space ground and a structure on a soil layer on rigid rock, are considered. Super-structure stiffness satisfying a desired stiffness performance condition are determined via an inverse problem formulation for a prescribed ground-surface response spectrum. It is shown through a simple yet reasonably accurate model that the ground conditions, e.g. homogeneous half-space or soil layer on rigid rock (frequency-dependence of impedance functions), ground properties (shear wave velocity), depth of surface ground, have extensive influence on the super-structure design.

• Fashion, Industry and Education
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• v.16 no.1
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• pp.36-45
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• 2018

Recently China has become one of the major markets for luxury brands. In addition, practicing social responsibility by manufacturers of luxury brands has become ubiquitous because consumers' perception of such practices may affect their purchase decisions positively. This study explored Chinese shoppers' perception of luxury brands' social responsibility practices and their information seeking behavior. In this study, value congruence was used as a theoretical framework. Twelve participants were selected out of customers in a shopping mall in Beijing, and they were subject to in-depth interview. The interview consisted of open-ended questions about perception of luxury brands' social responsibility practices, sources to access such practices, and the degree of personal value congruence to such practices as well as demographic information. Qualitative approach was used to analyze the data. Half of the participants indicated their awareness of the social responsibility practices of luxury brands, which sets up a foundation for understanding importance of luxury brands' social responsibility practices. Approximately half of the participants preferred to learn about luxury brands' socially responsible practices online especially via social media. These findings imply that Chinese luxury shoppers' trust and preference for the companies would be enhanced by effective development and advertisement of companies' social responsibility practices, and thus provide luxury companies with useful information on marketing strategies.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2004.11a
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• pp.179-180
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• 2004

In the information society, individual, enterprise and nation must be equipped with environmment and competence with which they can acquire useful information anytime and anywhere to process and utilize it in required form. Therefore, this study intends to investigate how digital TV, refrigerator and computer are laid out in the residential space in terms of life space, analyze the preference of residents an d forecast the preferred functions of the products to be introduced in the future. To build frame for making questionnaire tool of this survey, 3 households of the first constructor among the top-ranked constructors in the first half of 2004 were chose and in-depth interview was made from April 12 to April 17. On the basis of result of preliminary survey obtained by this process, the questionnaire was revised and supplemented. Targeting those living at the apartment house in Seoul and constructors ranked in top-four in the order of construction of the first half of 2004, I selected 3 households for each group in the range of 30$^{\sim}$40 pyung. Twelve cases were surveyed from April 19, 2004 to June 5, 2004. First, TV will continue playing the role of central entertainment mustering family at one place rather than separating them to each room. Second, in the case of refrigerator, the function is being subdivided, making 2 types, refrigerator and kimchi refrigerator indispensable, which was in just unit in the past Third, while computer was usually placed in the individual bedroom,

• Perspectives in Nursing Science
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• v.9 no.2
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• pp.71-82
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• 2012

Purpose: The aim of this study was to identify contraception behaviors in unmarried men and women. Methods: A descriptive qualitative study design was used. Individual in-depth interviews with fifteen participants were conducted. Content analysis was utilized to determine the main outcomes. Results: For men, three themes were consistently seen as contraception behaviors: 'men desired sexual intercourse greatly', 'men would not use a contraceptive device, even though they knew it was necessary', and 'men gradually considered contraceptive use to live their lives without interruption'. For women, the three themes were as follow: 'women had sex half willingly while half did not have sexual inter course for the first time', 'women did not use contraceptive devices because of ignorance of contraceptive methods', and 'women did not carefully consider contraceptive use'. Conclusion: To prevent unmarried men and women from having unplanned pregnancies, tailored sex education programs should be established throughout Korea. All things considered, the effect of multimedia sex education should be considered to maximize the use of contraceptive devices.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2709-2716
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• 2020

Compositions of large nuclear cores (e.g. boiling water reactors) are highly heterogeneous in terms of fuel composition, control rod insertions and flow regimes. For this reason, they usually lack high order of symmetry (e.g. 1/4, 1/8) making it difficult to estimate their neutronic parameters for large spaces of possible loading patterns. A detailed hyperparameter optimization technique (a combination of manual and Gaussian process search) is used to train and optimize deep neural networks for the prediction of three neutronic parameters for the Ringhals-1 BWR unit: power peaking factors (PPF), control rod bank level, and cycle length. Simulation data is generated based on half-symmetry using PARCS core simulator by shuffling a total of 196 assemblies. The results demonstrate a promising performance by the deep networks as acceptable mean absolute error values are found for the global maximum PPF (~0.2) and for the radially and axially averaged PPF (~0.05). The mean difference between targets and predictions for the control rod level is about 5% insertion depth. Lastly, cycle length labels are predicted with 82% accuracy. The results also demonstrate that 10,000 samples are adequate to capture about 80% of the high-dimensional space, with minor improvements found for larger number of samples. The promising findings of this work prove the ability of deep neural networks to resolve high dimensionality issues of large cores in the nuclear area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.1
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• pp.90-100
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• 2021

In the north and northeast of Cheonsu Bay, short-term fluctuations of surface water temperature are large owing to shallow water depth, weak current, and freshwater runoff. However, in the south of the bay, water temperature fluctuations are small owing to the inflow of offshore water by tidal currents. The water temperature in the north of the bay is higher in spring and summer than in the south of the bay, but lower in autumn and winter. During spring season, the fluctuation in the northern surface water temperature is the highest. The temperature fluctuations owing to tides are in phase with the tide in autumn and winter, and in the reverse phase with the tide in spring and summer. The dominant periods of water temperature fluctuations are half a day, daily, 15 days, and 1 month owing to the tide and 7 to 10 days, which are estimated based on atmospheric factors. Half a day and daily water temperature fluctuations are also highly correlated with air temperature and wind fluctuations. The sea area where water temperature fluctuations are highly correlated is divided into the north and south of the bay. The fluctuation phase is faster in the north of the bay than in the south or in the center.