• Geomechanics and Engineering
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• v.29 no.4
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• pp.435-449
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• 2022

In this paper, unreinforced and geogrid-reinforced soil foundations were modeled by discrete element method and this performed under surface strip footing loads. The effects of horizontal position of geogrid, vertical position, thickness, number, confining pressure have been investigated on the footing settlement and propagation of tensile force along the geogrids. Also, interaction between rectangular tunnel and strip footing with and without presence of geogrid layer has been analyzed. Experimental results of the literature were used to validation of relationships between the numerically achieved footing pressure-settlement for foundations of reinforced and unreinforced soil. Models and micro input parameters which used in the numerical modelling of reinforced and unreinforced soil tunnel were similar to parameters which were used in soil foundations. Model dimension was 1000 mm* 600 mm. Normal and shear stiffness of soils were 5*10⁵ and 2.5 *10⁵ N/m, respectively. Normal and shear stiffness of geogrid were 1*10⁹ and 1*10⁹ N/m, respectively. Loading rate was 0.001 mm/sec. Micro input parameters used in numerical simulation gain by try and error. In addition of the quantitative tensile force propagation along the geogrids, the footing settlements were visualized. Due to collaboration of three layers of geogrid reinforcements the bearing capacity of the reinforced soil tunnel was greatly improved. In such practical reinforced soil formations, the qualitative displacement propagations of soil particles in the soil tunnel and the quantitative vertical displacement propagations along the soil layers/geogrids represented the geogrid reinforcing impacts too.

• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.2
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• pp.190-202
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• 1995

The Optical Art is based on the principle of visual perception of the illusionary effects which induce psychological responses. It has influenced greatly on the Texile Design in that unique iJlusionary creativity of pattern simulates the visual sense of special movement; the dynamic psylosophy of vitalism. The Optical pattern has become a highly valued item due to its innovative effect in aesthetic direction. According to Vitor Vasarely the pioneer in this area, the integration and the inseparability of form and color which he calls 'Plastic Unity' provides the basis for the composition of infinite variety. The composition of infinite variety. The composition reveals the complex interaction between the space and form relating to order, repetition, combination and permutation. It is not simple to create optical patterns due to the extreme complexity composed by the multi-dimension and the infusion of form and color giving immensely varied movement. The purposes of this study are as follows; 1) to classify the complex processes of optical pattern on the basis of formative method. 2) to develop creative ideas for progressive contemporary textile design In this study, the analysis of applied methods is concentrated, which is based 1) on the gradual modification and on the transformation of the basic plastic elements which depend on thle direction of visual points involVing contradictory perspectives 2) on the composition varied special situations by repeating, overlapping and converging a series of idetUical units or by means of irrdiation, radiation and etc.

• Bulletin of the Society of Naval Architects of Korea
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• v.25 no.2
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• pp.19-30
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• 1988

Sectional added masses of an elastic beam vibrating vertically on the free surface in higher harmonic modes are evaluated. Hydrodynamic interactions between neighboring sections, which strip theory ignores, are considered for modal wave lengths of the order of magnitude of cross-sectional dimensions of the body. An approximate solution of modified Helmholtz equation which becomes a singular perturbation problem at small wave lengths is secured to get an analytic expression for added masses attending higher harmonic modes. As a bound of the present theory, the modified Helmholtz equation is solved for the long flat plate vibrating at high frequency on the water surface without any limitations on modal frequency. Finally, extensive series of numerical calculations are carried out for ship-like forms. It is found that when modal wave length is comparable to or shorter than a typical cross-sectional dimension of a body, sectional interaction effects are large which result in considerable reductions in added masses. For a fuller section, the ratio of added mass reduction is greater. In the limit of vanishing sectional area, the added masses approach to that of flat plate of equal beam. It is shown that the added mass distribution for a Legendre modal from can be determined form the present theory and that the results agree with the extensive three-dimensional determination of Vorus and Hilarides.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.5
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• pp.714-723
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• 2000

The purpose of this study is to develop functional and sensible brassiere for middle-aged women. As a methodology, engineering design process, especially, QFD(Quality Function Deployment) was adopted to translate consumer's needs into product design parameters. Wearing tests of commercial brassiere were performed for the development o subjective measurement scale. The environmental condition was controlled at 28$\pm$1$^{\circ}C$, 65$\pm$3%RH. As results, subjective measurement scale and dimension for the evaluation of sensible brassiere were extracted from factor analysis. Four factors were fitting, aesthetic property, pressure sensation, displacement of brassiere due to movement. Regression equations with the subjective evaluation descriptors were developed for the prediction of wearing comfort of brassiere. (R2=.82) The most critical design parameter was wire-related property and second one was stretchability of main material of brassiere. Also, wearing comfort of brassiere was affected by the interaction of initial stretchability of wing and support of strap.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.163-170
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• 2002

In this paper, silk fibroin (SF)/polyurethane (PU) blend films were fabricated to develop a new biomaterial for biomedical applications. These blend films were prepared using formic acid as a cosolvent, and structural characteristics and properties of blend films were investigated. FTIR results suggested that there was no specific interaction between SF and PU, implying molecular immiscibility in SF/PU blend films. Furthermore, it was revealed by XRD method that the crystalline region of blend components was not perturbed by counterpart polymers. The degree of phase separation of SF/PU blend films was diminished by increasing PU content in blend. Especially, the blend with 70% content of PU showed no evidence of macro-phase separation in SEM observation. However, SF/PU blend (70/30) was revealed to be phase-separated in a lower dimension confirmed by DMTA measurement. TGA result showed that thermal decomposition temperature of blend film was slightly decreased compared to those of SF and PU polymer itself, Though mechanical properties of SF/PU blend films were not good enough due to the solvent, blood compatibility of PU can be enhanced markedly by mixing with SF for SF/PU blend film.

• Knowledge Management Research
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• v.12 no.1
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• pp.53-76
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• 2011

This study aims to examine the effects of on premium convergence products buying behavior. This paper analyzed the positive attitude formation using the basic and extended TAM and also revealed how the positive premium convergence product attitude relate to relationship purchasing intention and word of mouth intention. The samples of 562 consumer indicate that the antecedents are consist of four dimension(perceived usefulness, perceived ease of use, social value) and attitude is developed into buying intention and word of mouth intention. We have reached the following conclusion about the antecedents and outcomes factors of customer attitude for the launch of premium convergence product. First, perceived usefulness, perceived delight, and social value had a positive effect on customer attitude but perceived ease of use did not. Second, we found that customer attitude had a positive effect on purchase intention and word-of mouth intention. Finally, interaction effect of perceived usefulness/perceived delight and social value had a positive effect on customer attitude. Our findings suggested that adoptian and diffusion of premium convergence product is influenced by several behavior factors. Managerially, our result emphasize that premium convergence products must satisfy not only the perceived usefulness/delight but also social value that consumers are seeking in order to be successful in the market. The theoretical and practical implications of these findings are discussed as well.

• International Journal of Naval Architecture and Ocean Engineering
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• v.2 no.3
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• pp.146-154
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• 2010

In the present study, the wave excitation forces acting on an array of porous circular cylinders are examined based on diffraction problems. To calculate the wave forces, the fluid domain is divided into three regions i.e. a single exterior region, N interior regions and N beneath regions, and the diffraction in each fluid region is expressed by an eigenfunction expansion method with using 3-dimension liner potential theory (Williams and Li, 2000). Especially, the present method is extended to the case of an array of truncated porous circular cylinders to calculate the heave forces as well as surge and sway forces. To verify this method, the numerical results obtained by eigenfunction are compared with these results obtained by higher order boundary element method (Choi et al., 2000). The numerical results obtained by this study are in good agreement with those results. By changing the numbers of porous circular cylinders, the angle of incident wave and the porosity rate of circular cylinders, the wave excitation forces such as surge, sway and heave on an array of truncated porous circular cylinders are investigated.

• Proceedings of the ESK Conference
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• 1997.10a
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• pp.249-259
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• 1997

As the gap between competing products narrows in terms of performance and quality, the product usability is rapidly becoming a new dimension of product design as the key to offering distinctive value to the customer. Because the user interface is important, not only for the user but also for the efficiency of te whole organiation, system designers require increasingly precise evaluation methods to determine how effective and usable human-product interface is. In this study a new methodology named usability analysis diagram(UAD), for evaluating usability of human-product interface systematically, was developed. UAD is a top-down flow diaagram of a human-product interaction, in ehichfour basic elements - perception, understanding, intellectual decision and action - were classified and then represented by a particular symbol for each. The usability of the product is assessed by the frequency of each symbol in a diagram which represents a sequence of cognitive and physical activities of users during the use of the product, and by the level of difficulty that is classif- ied in three levels in terms of easiness of perception, understanding and action. In order to test validity of the proposed UAD in a real situation, a case study was performed on two different cameras, automatic and manual, and their usability was successfully evaluated and compared.

• Computers and Concrete
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• v.27 no.1
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• pp.1-12
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• 2021

This work presents a safety assessment of an underground tunnel subjected to a ballistic missile attack employing the numerical approach. For the impact simulation, a box shaped reinforced concrete (RC) structure with a cross section dimension of 8.0×10.0 m under a soil layer that was attacked by a SCUD missile was modeled using finite element (FE) software LS-DYNA. SCUD missile is one of a series of tactical ballistic missiles developed by Soviet Union during the Cold War, which is adopted for a short-range ballistic missile. The developed FE simulation for the penetration depth of the missile impacting into the soil structure was verified from the well-known formula of the penetration prediction. The soil-structure interaction, the soil type, and the impact missile velocity effects on the penetration depth of the missile into the different soil types were investigated. The safety assessment of the underground tunnel was performed with regard to the different depths of the underground tunnel. For each missile velocity and soil type, a specific depth called the unsafe depth was obtained from the analysis results. The structure beneath the soil beyond this depth remains safe. The unsafe depth was found to be increased with the increasing missile velocity.

• The Journal of the Acoustical Society of Korea
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• v.28 no.3E
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• pp.109-117
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• 2009

Identity recognition in real environment with a reliable mode is a key issue in human computer interaction (HCI). In this paper, we present a robust person identification system considering score-based optimal reliability measure of audio-visual modalities. We propose an extension of the modified reliability function by introducing optimizing parameters for both of audio and visual modalities. For degradation of visual signals, we have applied JPEG compression to test images. In addition, for creating mismatch in between enrollment and test session, acoustic Babble noises and artificial illumination have been added to test audio and visual signals, respectively. Local PCA has been used on both modalities to reduce the dimension of feature vector. We have applied a swarm intelligence algorithm, i.e., particle swarm optimization for optimizing the modified convection function's optimizing parameters. The overall person identification experiments are performed using VidTimit DB. Experimental results show that our proposed optimal reliability measures have effectively enhanced the identification accuracy of 7.73% and 8.18% at different illumination direction to visual signal and consequent Babble noises to audio signal, respectively, in comparison with the best classifier system in the fusion system and maintained the modality reliability statistics in terms of its performance; it thus verified the consistency of the proposed extension.