• Journal of the Korean Society for Precision Engineering
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• v.27 no.8
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• pp.76-83
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• 2010

Metallic sandwich panels with pyramidal truss structures are high-stiffness and high-strength materials with low weight. In particular, bulk structures have enough space for additional multi-functionalities. In this work, in order to fabricate 3-D structures efficiently, Layered Manufacturing Method (LMM) which was composed of three steps, including crimping process, stacking process and bonding process using rapid infrared brazing, was proposed. The joining time was drastically reduced by employing infrared brazing of which heating rate and cooling rate were faster than those of conventional furnace brazing. By controlling the initial cooling rate slowly, the bonding strength was improved up to the level of strength by conventional vacuum brazing. The observation of infrared brazed specimens by optical microscope and SEM showed no defect on the joining sections. The experiments of 1-layered pyramidal structures and 2-layered pyramidal structures subject to 3-point bending were conducted to determine structural advantages of multilayered structures. From the results, the multi-layered structure has superior mechanical properties to the single-layered structure.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.597-600
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• 2009

Sound transmission loss (TL) is experimently investigated on the multi-layered panel used for the floor of a tilting train. Measurement of the intensity transmission loss is performed according to ASTM E 2249-02. The floor structure consists of corrugated steel panel, glass wool, plywood and cover. On the corrugated steel panel, TL drop by local resonance is considered and the TL improvement effect by damping treatment is estimated. Total sound transmission loss of the entire floor structure is obtained and the contribution of each layer is examined.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2256-2262
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• 2011

In this study, sound transmission loss (STL) is investigated on the multi-layered windows used in the KTX-sancheon and next generation HEMU-400x high speed train. Using TLOSS, which is developed as a special purpose STL analysis program, STLs of the multi-layered glass windows are analytically investigated and compared with the mass law result. Window specimens for the two train models are manufactured and intensity transmission losses are measured based on ASTM E2249-02. The problems in aspect of sound insulation are diagnosed on the two window models. The aim of this study is to provide useful data for the improvement of the interior noise in the high speed train.

• Journal of the Optical Society of Korea
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• v.17 no.2
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• pp.205-212
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• 2013

Pain is one of the quite common symptoms in clinics and many treatment methods have been applied to relieve pain. Among the treatments, high-intensity light therapy for pain has been introduced, but this therapy has not been fully supported by confirmed efficacy due to the absence of quantitative assessments and treatment feedback data in real time. In this study, the evaluation of light distribution in tissue was performed with current high-intensity light sources quantitatively using light-tissue interaction simulations. The diffuse reflectance in tissue was generated using Monte Carlo simulation that traces photons as they undergo multiple scattering and absorption within each tissue layer (skin, fat, and muscle) and within multi-layered tissue. The results showed that the highest diffuse reflectance and the deepest penetration of tissue were achieved at ${\lambda}$=830 nm when compared with other wavelengths like ${\lambda}$=650 nm, 980 nm and 1064 nm.

• Elastomers and Composites
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• v.52 no.4
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• pp.272-279
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• 2017

The heterocoagulation of latex is a simple and useful method to fabricate various polymer nanocomposites in which a precise control of the colloid stability is essential. In this work, a multi-layered graphenes (MLGs)/poly(styrene-co-butyl acrylate) (P(S-co-BA)) nanocomposite having an excellent dispersion of MLGs was prepared via the sudden heating heterocoagulation process. The P(S-co-BA) component was obtained by emulsion polymerization. This process can effectively shorten the process and particles growth steps. The colloid stability of these dispersions was controlled by factors such as ionic charge, temperature, and reaction times. The influence of these factors on heterocoagulation was evaluated and the properties of the nanocomposites were investigated. The conductivity of the MLGs/P(S-co-BA) nanocomposites increased from -11.53 to -5.70 S/cm for an increase in MLG content from 0.01 to 5 wt%. Moreover, percolation threshold was observed in the case of 0.01 wt% MLGs.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.421-430
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• 2000

We apply the Rayleigh Ritz method to analyze multi-layered plates with residual stresses. The method is very simple, straight forward, and easily programmable, but it should be applied to structure s only in simple shapes. We derive coupled variational equations based on the principle of virtual displacement, and investigate what kind of basis functions is desirable for the analysis of rectangular plates with various boundary conditions. We demonstrate the effectiveness and usefulness of the method through several examples. The analysis results obtained with the method are in good agreement with those available in literature. A multi-layered MEMS plate example shows that the coupling effect should not be ignored and that residual stresses do influence the stiffness of the structure very much.

• Journal of Multimedia Information System
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• v.1 no.1
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• pp.1-10
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• 2014

In this paper, we propose a new view synthesis technique for coding of multi-view color and depth data in arbitrary camera arrangements. We treat each camera position as a 3-D point in world coordinates and build clusters of those vertices. Color and depth data within a cluster are gathered into one camera position using a hierarchical representation based on the concept of layered depth image (LDI). Since one camera can cover only a limited viewing range, we set multiple reference cameras so that multiple LDIs are generated to cover the whole viewing range. Therefore, we can enhance the visual quality of the reconstructed views from multiple LDIs comparing with that from a single LDI. From experimental results, the proposed scheme shows better coding performance under arbitrary camera configurations in terms of PSNR and subjective visual quality.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.225-228
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• 2002

The adhesion effect between the oxide layer and the metal layer has been studied by RTP anneal. Two types of oxides, BPSG and P-TEOS, were used as a bottom layer under multi-layered metal film. We observe the interface between oxide and metal layer using SEM (scanning electron microscopy), TEM (transmission electron microscopy), AES (auger electron spectroscopy). Adhesion failure was occurred by interfacial reaction between the BPSG oxide and the multi-layered metal film at 650"C RTP anneal. The phosphorus rich layer was observed at interface between BPSG oxide and metal layer by AES and TEM measurements. On the other hand adhesion was a)ways good in the sample used P-TEOS oxide as a bottom layer. We have known that adhesion between BPSG and multi-layered metal film was improved when the sample was annealed below $650^{\circ}C$.TEX>.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.1048-1055
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• 2003

This paper proposes a new method of solving integrated problems that consist of several sub-problems in a symmetric multi-layered structure, and also demonstrate the applicability of the method. The proposed method is named Symmetric Multi-layered Coevolutionary Algorithm (SMCA). The SMCA imitates partly the natural process of endosymbiotic evolution, which is a special type of coevolution. The SMCA is applied to the process planning problem in flexible manufacturing system (FMS), taking account of the flexibility of machine, tool, process, and sequence. To do this, SMCA's components are studied and its strategies are developed to improve the performance. The proposed algorithm is compared with the existing ones in terms of solution quality. The experimental results confirm the effectiveness of our approach.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.4
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• pp.279-288
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• 2011

The past researches focused on the supply chain network that consists of factories, distribution centers and retailers for single product type. This research is required because the factory for single product type is advanced to reconfigurable type in order to produce various products, according to customers' various purchase forms and time. This research is also required because in the past researches, the material flows from factories to distribution centers and from distribution centers to retailers, but recently, there are material flows between distribution centers. The supply chain network in this research consists of reconfigurable manufacturing system, multi-layered distribution centers, and retailers. A simulator is developed to analyze the material flow on the supply chain network. The developed simulator is web-based designed by using Java Server Page and MS-SQL, so as to maximize the convenience for users.