• Macromolecular Research
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• v.17 no.4
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• pp.271-275
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• 2009

This paper describes the out-of-plane order of a liquid crystalline(LC) methacrylate copolymer(3) comprised of a methacrylate(1) with a 4-styrylpyridine moiety as the photo-cyclodimerizable group and a benzoate moiety as the mesogenic group in the side chain, and another methacrylate(2) with a 4-(4-methoxyphenyl)benzoate moiety as the mesogenic group. The composition of 1 and 2 units in 3 was estimated to have a molar ratio of 54.2:45.8 by $^{1}H$ NMR spectroscopy. The X-ray diffraction study revealed that the copolymer forms a partial bilayer smectic structure. The copolymer gave rise to a high out-of-plane order parameter of about 0.74 in a wide LC temperature range of $110{\sim}160^{\circ}C$ after linearly polarized, UV light irradiation and subsequent annealing. Moreover, the external reflection IR analysis indicated that excess UV-light irradiation makes the out-of-plane LC structure of the copolymer appear in a higher and wider temperature range.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.2
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• pp.49-59
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• 2000

Wave distribution in Jangjeon Harbour is numerically simulated for an optimum design of the harbour facilities. A deep-water design wave is estimated based on stochastic extreme wave analysis of wind data in the vicinity of the harbour, and it is applied to the boundary condition at open sea. Boussinesq wave theory that includes effects of frequency dispersion and nonlinearity is employed for the wave simulation. The porosity and sponge layer are adapted at beach to depict partial reflection and complete absorption of waves, respectively. The design wave for breakwater is computed in global domain with coarse grids and the wave distribution inside of wharf is simulated in local domain with fine grids.

• Journal of Biomedical Engineering Research
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• v.28 no.4
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• pp.471-476
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• 2007

Various active microwave imaging techniques have been developed for cancer detection for past several decades. Both the microwave tomography and the UWB radar techniques, constituting functional microwave imaging systems, use the electrical property contrast between normal tissues and malignancies to detect the latter in an early development stage. Even though promising simulation results have been reported, the understanding of the functional microwave imaging diagnostics has been relied heavily on the complicated numerical results. We present a computationally efficient and physically instructive analytical electromagnetic wave channel models developed for functional microwave imaging system in order to detect especially the breast tumors as early as possible. The channel model covers the propagation factors that have been examined in the previous 2-D models, such as the radial spreading, path loss, partial reflection and transmission of the backscattered electromagnetic waves from the tumor cell. The effects of the system noise and the noise from the inhomogeneity of the tissue to the reconstruction algorithm are modeled as well. The characteristics of the reconstructed images of the tumor using the proposed model are compared with those from the confocal microwave imaging.

• Journal of the Korean Operations Research and Management Science Society
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• v.33 no.1
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• pp.131-148
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• 2008

Today, it is not difficult to use information technology (IT), especially, Internet based ones. Many people can not only access IT without learning how to use it but also find and develop new techniques and usages which couldn't be expected by system engineers or designers. This is owing to social interactions among users as well as advancement of IT. Theoretically, such social interactions in using IT can be well explained by adaptive structuration theory (AST) which has been considered as one of trying to capture the change of using IT due to social interactions between users and system. This study is to analyze the relationship between social interactions and motivation in using IT which can determine attitude and intention of using IT. For this purpose we provide a research model, in which two AST related variables, faithfulness of appropriation and consensus on appropriation, are independent variables and three beliefs for using IT, usefulness, ease of use and playfulness, are dependent ones. Additionally, for reflection of changing uses, usefulness is formed as second order factor by two first order factors-usefulness of self-expression and communication. An empirical test of our model for blog users which is analyzed by Partial Least Square method shows supporting most of hypotheses except one, consensus-ease of use.

• Fashion & Textile Research Journal
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• v.9 no.4
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• pp.363-372
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• 2007

T-shirt has changed into advanced and stylish outwear by new paradigm, taste of consumer, awareness of recycling, spread of subculture, DIY culture, refusal of standardization and pursuit of high quality goods, etc. The purpose of this study was to analyze aesthetic characteristics of t-shirt designs that changed into diverse designs in world fashion college since 2000. The method of this study was to analyze documentaries, fashion magazines and internet fashion site. Aesthetic characteristics of t-shirt designs were expressed in deconstruction, mixture, integration and imitation. And each of external expressions and internal meanings was as follows: First, deconstruction was expressed in partial cutwork and three dimensional texture by sewing and construction drape. It means breaking the conventional structure and break-ing the boundary of t-shirt and another item and possibility of multi-vocal analysis. Second, mixture was expressed in collage of diverse ornaments, diverse fabrics and diverse patterns. It means exceeding the limit of material, elaboratenes and high quality of handwork, reflection of self-identity, brand image, fashion trend, consumer's psychology and mind of experimentation and couture. Third, integration was expressed in extension of length, width, use and style. It means unification of functions, deconstruction of items and extension of meanings and images. Forth, imitation was expressed in stain of dye, irregular and ripped sign, cut out, rough warp, drawing and washing, etc. It means subculture, rarity value, monopolization, diversity, familiarity, yearning and uniqueness.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.5
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• pp.273-283
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• 2013

The traditional medical equipments are devices used by medical professionals but not used in public environment. Common people, however, require light-weight medical devices to make healthcare for themselves nowadays. Those medical devices are used to monitor personal health status such as blood pulse, blood pressure, diabetes. Also, some of them are operated in mobile environment called u-healthcare. This paper implements a portable healthcare system composed of $SpO_2$(Saturation of Partial Pressure Oxygen) sensors and a gateway for detecting hypoxemia during people's leasure activity such as climbing or hiking. The $SpO_2$ sensor is designed as watch style to support dynamic exercise and the gateway is designed as necklace style to support the elderly. The result of a performance evaluation shows that the performance of the $SpO_2$ sensor using reflection technology is not lower than that of a clairvoyant styled $SpO_2$ sensor.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.1
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• pp.39-44
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• 1993

This paper is concerned with developing a finite element model incorporating boundary damper techniques which is applicable to the prediction of wave agitations in harbors. Based on the linear wave theory, a mild-slope equation is used. In order to consider the wave energy dissipations on solid boundary. the partial reflecting boundary condition is introduced. Radiating boundary condition is modeled by using tile second-order boundary damper developed by Bando et al. (1984). The near field region in harbor is discretized using 8-noded isoparametric elements, the boundary conditions are presented using 3-noded line elements. The numerical model is applied to a fully open rectangular harbor to prove its validity. Numerical experiments are also performed to investigate the effects of the wave reflection coefficients of solid boundary and the types of the dampers.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.514-514
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• 2017

Floating breakwaters were treated as solid bodies without any perforation in previous studies. In this study, however, a floating breakwater is perforated to allow the partial absorption of the energy produced by incident waves and an air chamber is placed in the upper part to control the breakwater draft. A series of laboratory experiments for a floating breakwater installed with a mooring system are carried out. In general, a mooring system can be classified by the number of mooring points, the shape of the mooring lines, and the degree of line tension. In this study, a four-point mooring is employed since it is relatively easier to analyze the measured results. Furthermore, both the tension-leg and the catenary mooring systems have been adopted to compare the performance of the system. In laboratory experiments, the hydraulic characteristics of a floating breakwater were obtained and analyzed in detail. Also, a hydraulic model test was carried out on variable changes by changing the mooring angle and thickness of perforated wall. A hydraulic model was designed to produce wave energy by generating a vortex with the existing reflection method. Analysis on wave changes was conducted and the flow field around the floating breakwater and draft area, which have elastic behavior, was collected using the PIV system. From the test results the strong vortex was identified in the draft area of the perforated both-sides-type floating breakwater. Also, the wave control performance of the floating breakwater was improved due to the vortex produced as the tension in the mooring line decreased.

• Fashion & Textile Research Journal
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• v.21 no.1
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• pp.75-87
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• 2019

The purpose of the study was to suggest a cycle wear top jersey improved in mobility. The study developed a new cycle wear with improvement in dissatisfaction factors by planning design, pattern and the functionality of fabric. Considering the amount of sweat and the necessities of compression part, the basic material, the additional compression material, and the mesh material were arranged differently according to areas. The assessment of the developed cycle wear was composed of wearing comfort evaluation by female cyclist, photo analysis and garment pressure evaluation. The developed cycle wear was evaluated and compared with the current cycle wear. As a result of wearing comfort evaluation, the developed cycle wear was evaluated as better than the existing ones in all part, particularly in the areas of reflection tape and materials, partial pressure, pocket size, and prevention of loss. Photo analysis was in agreement with the appearance evaluation of the participants. As a result of garment pressure evaluation, the front neck part was more comfortable and the upper arm, abdomen, and waist area showed higher pressure, so it partially supported the body. This study has significant meaning for developing a new cycle wear top, protecting the body and improving the exercise effect.

• Korean Journal of Metals and Materials
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• v.49 no.4
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• pp.329-333
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• 2011

To develop wide-band noise absorbers with a special design for low-frequency performance, this study proposes a tin oxide (Sn-O) thin films as the noise absorbing materials in a microstrip line. Sn-O thin films were deposited on polyimide film substrates by reactive sputtering of the Sn target under flowing $O_{2}$ gas, exhibiting a wide variation of surface resistance (in the range of $10^{0}-10^{5}{\Omega}$) depending on the oxygen partial pressure during deposition. The microstrip line with characteristic impedance of $50\Omega$ was used for the measurement of noise absorption by the Sn-O films. The reflection parameter $(S_{11})$ increased with a decrease of surface resistance due to an impedance mismatch at the boundary between the film and the microstrip line. Meanwhile, the transmission parameter $(S_{21})$ diminished with a decrease of surface resistance resulting from an Ohmic loss of the Sn-O films. The maximum noise absorption predicted at an optimum surface resistance of the Sn-O films was about $150{\Omega}$. For this film, greater power absorption is predicted in the lower frequency region (about 70% at 1 GHz) than in conventional magnetic sheets of high magnetic loss, indicating that Ohmic loss is the predominant loss parameter for the conduction noise absorption in the low frequency band.