• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.5
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• pp.92-103
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• 2015

Box-Wilson experimental design method, known as central composite design, is the design of any information-gathering exercises where variation is present. This method was devised to gather as much data as possible in spite of the low design cost. This method was employed to model the effect of mixing factors on several performances of 60 MPa high strength self compacting concrete and to numerically calculate the optimal mix proportion. The nonlinear relations between factors and responses of HSSCC were approximated in the form of second order polynomial equation. In order to characterize five performances like compressive strength, passing ability, segregation resistance, manufacturing cost and density depending on five factors like water-binder ratio, cement content, fine aggregate percentage, fly ash content and superplasticizer content, the experiments were made at the total 52 experimental points composed of 32 factorial points, 10 axial points and 10 center points. The study results showed that Box-Wilson experimental design was really effective in designing the experiments and analyzing the relation between factor and response.

• Journal of the Korean GEO-environmental Society
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• v.22 no.12
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• pp.15-24
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• 2021

In Korea, which is mostly mountainous, the proportion of tunnel and underground space development are increasing. Although the ground is reinforced by applying the ground improvement method during underground space development, accidents still occur frequently in Korea. In the grouting method, a representative ground reinforcement method, the effect was judged by comparing the total amount of injection material with the amount of injection material used during the actual grouting construction. However, it is difficult to determine whether the ground reinforcement is properly performed during construction or within the target ground. In order to solve this problem, it is necessary to study a new method for quality control during or after construction by measuring electrical resistivity after performing grouting by mixing carbon fiber, which is a conductive material, and microcement, which is a grout material. In this study, as a basic study, a cement specimen mix ed with 0%, 3%, 5%, 7% of carbon fiber was prepared to evaluate the performance of the grout material mixed with carbon fiber, which is a conductive material. The prepared specimens were wet curing for 3 days, 7 days, and 28 days under 99% humidity, and then compression wave velocity and shear wave velocity were measured. As a result of the compression wave velocity and shear wave velocity measurement, it showed a tendency to increase with the increase in the compounding ratio of carbon fibers and the number of days of age, and it was confirmed that the elastic modulus and shear modulus, which are the stiffness of the material, also increased.

• Korean Journal of Construction Engineering and Management
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• v.9 no.1
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• pp.176-186
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• 2008

The radio frequency identification (RFID) technology allows various forms of applications in many industries including construction. and in Korea, RFID has already been adopted for the use in daily labor control, logistics monitoring of ready-mix concrete, supply chain management of long-lead items, such as structural steel members and curtain walls. Even though RFID tags have varied reading performances depending on various factors including material of tracking target and surrounding environment, there is no information on how much the reading performance of an RFID tag can be achieved against a specific construction components or materials. Therefore, the objective of this research is to identify the actual reading performance of various RFID technologies and to derive a method to maximize the reading performance for the use in the supply chain management process of curtain wall components.

• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.680-686
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• 2011

The purpose of this study was to analyze information about food and nutrition topics presented throughout the television broadcast media, thereby find out the optimal communication method to give desirable information to the general public. To perform this study were recruited and trained by monitoring education before and during the study. 3 domestic TV channels were selected to be monitored, for 3 months. Results of this study were as follows: First, the total reporting cases of information about foods and nutrition were 154, When each monitored contents was seen from the domain of programs, 128 cases(83.1%) were from current affairs and information program, and 26(16.9%) were from entertainment program. Second, according to survey by channel cases are 26(16.9%) from KBS, 54 cases(35.1%) from MBC, 74 cases(48.1%) from SBS, which means SBS reported the most about nutritional foods. Third, the frequency of reporting information on the overall diet and food & ingredient, cuisine & cookey, health & diet therapy and obesity & diet in order. Forth, among the 26 cases of positive or negative implications made by each cannel of KBS, 18 cases were delivered in positive ways, 7 cases had positive and negative point of views mix together, and 1 cases was negatively delivered. Finally, the most important thing is to organiae the advisory team by connecting mass media and specialist, and the educational program of nutrition should be developed for the communication of right information about foods and nutrition.

• The Research Journal of the Costume Culture
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• v.22 no.1
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• pp.86-98
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• 2014

This study analyzed fashion businesses based on the 6P's, products, prices, place, promotion, people, and patron for business owners in the Myeongdong commercial fashion district. Furthermore, this study proposed plans that would activate the Myeongdong fashion district and continuously develop it as a global fashion city. A survey was conducted from August to September, 2012 for 249 fashion business owners in Myeongdong. Eventually, only 208 questionnaires were used for the analysis. The research results were as follows. First, domestic brands have the largest share in the market and sales of fashion accessories were higher than the sales of clothes. Second, the prices for those fashion items ranged from low to mid-price. Third, the opening of new shops keeps increasing, and the size of the shops falls between ten and twenty pyeong generally. 'Self-production' was the highest form of production compared to any other form, and regarding importation sites, importation from overseas was the highest. Fourth, regarding promotion types, the sales in shops was the most commonly used promotion method compared to television and magazine advertising, and personal selling. Fifth, the proportion of male proprietors was larger than that of female proprietors. Most employees had less than five years of sales experience. Sixth, the main customers were females in their 20s and the proportions of Korean and foreign customers was similar.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.215-224
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• 2012

Using password on system is easy to build and shorten the access time to authorize user, which is high in use for vary system that requires users' authorization. Many input device are able to perform the password system easily, such as PC, smart-phone, tablet PC, etc. Beside the high usability of password, physical attack occurs when user put their password on the device, known as Shoulder Surfing attack. It used to be formed in numbers, characters or mix of different kinds, but new kind of password arose. Exploiting image or making scenarios are those kinds which are able to reflect users' intentions. Not many estimation exists for new password, so there's need to be standard for those new password for highlighting usability and accessability. In this paper, we propose password system with simple image and switching key-board to test statistical method to estimate usability on the password.

• Journal of the Korea Institute of Building Construction
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• v.15 no.6
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• pp.597-605
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• 2015

The method of concrete mix design used in this study aims to achieve the identical specified design strength, applying different types and replacement ratio of mineral admixtures and afterwards, fire tests were conducted using the standard time-temperature curve specified in the ASTM E119 to identify the influences of the types of mineral admixtures on the fire resistance performance of high strength concrete(HSC). The least spalling was observed in the test specimen containing blast furnace slag as a partial replacement of cement, while the most significant spalling phenomena were observed in the blast furnace slag test specimen that silica-fume was added in. In particular, the reasonable volume of spalling was observed when solely replaced by silica fume. However, the influence of the cement replacement by silica fume and blast furnace slag on the increases of spalling can be explained through blocked pores by the fine particles of silica fume, leading to decreases in permeability.

• Journal of the Korea Institute of Building Construction
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• v.15 no.6
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• pp.553-559
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• 2015

In this study, to suggest the application method of recycled fine aggregate, the non-cement mortar was prepared and studied with the binders of blast furnace slag, fly ash, and fly ash from combined heat power plant. As a basic experiment, a series of tests was conducted to determine the potions of the binders and types of activator. When the binder was consisted with 20% of fly ash and 40% of fly ash from combined heat power plant, the highest strength of the mortar was obtained, and as an activator, the combination of sodium hydroxide 2.5%, and calcium hydroxide 7.5% showed the highest strength of the mortar. Therefore, this study focuses on engineering properties of mortar contains fly ash from combined heat power plant and recycled fine aggregate according to replacement ratio of recycled fine aggregate based on the optimum mix from the basic experiment. As a result, the best replacement ratio of recycled fine aggregate is 75%.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.579-586
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• 2010

With the development of micrototal analysis systems (${\mu}TAS$), which is a result of enhancement of MEMS technology, rapid progress has been achieved in medical and biological research. The study of lab-on-a-chip (LOC) devices, which are types of ${\mu}TAS$ and which integrate the functions of mixing and analyzing tiny amounts of samples and reagents on one chip, has actively progressed. An LOC comprises microfluidic components such as micromixers and micropumps. Because the flow in a microfluidic system is generally laminar, it is very difficult to efficiently mix and feed fluid reagents. This paper presents the design and the method of fabrication of an MHD micropump for mixing fluids. By using this micropump, fluids are simultaneously mixed and pumped; this is achieved by coupling the Lorentz force and force exerted by an electric charge moving in an electric field.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.6
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• pp.445-454
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• 2001

The stochiometric mix of evaporating materials for the CuInSe$_2$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, CuInSe$_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy(HWE) system. The source and substrate temperature were 62$0^{\circ}C$ and 41$0^{\circ}C$, respectively. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of CuInSe$_2$ single crystal thin films measured from Hall effect fby van der Pauw method are 9.62x10$^{16}$ cm$^{-3}$ , 296$\textrm{cm}^2$/V.s at 293 K, respectively. From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the CuInSe$_2$ single crystal thin film we have found that he values of spin orbit splitting ΔSo and the crystal field splitting ΔCr were 6.1 meV and 175.2 meV at 10K, respectively. From the photoluminescence measurement on CuInSe$_2$ single crystal thin film we observed free excition (Ex) existing only high quality crystal and neutral bound exiciton (D$^{\circ}$,X) having very strong peak intensity. Then, the full-width-at-half-maximum(FWHM) and binding energy of neutral donor bound excition were 7meV and 5.9meV, respectivity. by Haynes rule, an activation energy of impurity was 50 meV.