• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.5
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• pp.471-482
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• 2016

In this study, we focused on a speed-up of KIESSI-3D program, which is based on FE-IE techniques, by introducing a p-version dynamic infinite element method. In order to evaluate performance of the KIESSI-3D, numerical analyses for eight real-scale SSI problems are carried out. We considered three types of KIESSI-3D numerical models whose radii of near-field soil region($r_0$)are 1.2, 1.5, and 3.0 times of basemat radius of structure(R). In addition, SSI analyses using the SASSI2010 program are carried out used for comparison of accuracy and runtime against those of the KIESSI-3D. Numerical results show that the KIESSI-3D model of $r_0=1.2R$ is enough to give accurate solution. In view of the computing speed, the new KIESSI-3D was up to 25 times faster than the old KIESSI-3D.

• Journal of the Korean Ceramic Society
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• v.48 no.6
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• pp.487-492
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• 2011

The effect of the application of lanthanum strontrium manganite and yttria-stabilized zirconia (LSM-YSZ) nano-composite fabricated by pulsed laser deposition (PLD) as a cathode of solid oxide fuel cell (SOFC) is studied. A gradient-structure thin-film cathode composed of 1 micron-thick LSM-YSZ deposited at an ambient pressure ($P_{amb}$) of 200 mTorr; 2 micron-thick LSM-YSZ deposited at a $P_{amb}$ of 300 mTorr; and 2 micron-thick lanthanum strontium cobaltite (LSC) current collecting layer was fabricated on an anode-supported SOFC with an ~8 micron-thick YSZ electrolyte. In comparison with a 1 micron-thick nano-structure single-phase LSM cathode fabricated by PLD, it was obviously effective to increase triple phase boundaries (TPB) over the whole thickness of the cathode layer by employing the composite and increasing the physical thickness of the cathode. Both polarization and ohmic resistances of the cell were significantly reduced and the power output of the cell was improved by a factor of 1.6.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.8
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• pp.906-912
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• 2008

We designed and implemented a 3-dimensional structure internal antenna which has volume less than 1.5 cc for mobile phone to improve efficiency and gain. Multiple bending for the resonance of small internal antenna derives reduction of gain due to cancellation of antenna current. In this study, the current cancelation was reduced by the minimization of antenna bending. And the helix element was applied for the purpose both compensation of short antenna length and action of radiation element. For the verification of this study, a 1.5 cc volume 3D antenna which was fabricated by the press method applied to the dual band mobile phone. Measurement showed that efficiencies and gains under the slide down and up were 27.73 %, 0.29 dBi for the GSM band and 46.84 %, 2.27 dBi for the USPCS band, and had good performance under the small antenna volume. H-plane radiation pattern showed omnidirectional for the both band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.7
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• pp.737-743
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• 2011

In this paper, we designed and implemented a Monopole+IFA(Inverted F Antenna) hybrid antenna using the coupled feeding structure for the all band mobile phone. Studied antenna has wide band characteristics by the simultaneous operation both monopole and IFA under the coupled feeding structure. An antenna has designed PCB embedded type without antenna carrier component for the low in cost. Implemented antenna has within 2.5:1 for VSWR under LTE/CDMA/GSM900/DCS/USPCS/WCDMA/WiBro/WiFi in all band for the mobile services Measured average gains and efficiencies were -3.98~-0.09 dBi and 40.03~97.99 % for the LTE, CDMA, GSM900 band, and -3.90~-1.01 dBi and 40.70~79.31 % for the DCS, USPCS, WCDMA, WiBro, WiFi band. It's shown that studied antenna can be applied to all band mobile phone antenna including LTE.

• Journal of KIISE:Databases
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• v.32 no.3
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• pp.326-333
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• 2005

Many XML applications use XPath Patterns as a query language for XML documents. Two XPath patterns may have containment relationship, and the containment problem between two XPath patterns is a problem that determines whether one XPath pattern contains another XPath Pattern. Although the containment problem occurs in many applications, it is known as a co-NP complete. A homomorphism problem, which is a sufficient condition for the containment problem, is solved in polynomial time. We first discuss applications that replace the containment problem with the homomorphism problem, and maintaining homomorphism information among XPath patterns will benefit those applications. Then, we propose a lattice structure, called POX (Partially Ordered Set of XPath Patterns), and develop algorithms for maintaining it. As our analyses show, the algorithms can efficiently maintain POX in polynomial time.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.10 no.2
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• pp.64-72
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• 1998

Dynamic response analysis is carried out for slender marine structures such as tensioned risers and tethers of tension leg platform, which are subjected to floating vessel motions as well as environmental forces arising from ocean waves. A mumerical analysis procedure is developed by using finite element model of the structural member. Dynamic analses are performed in the time domain for regular waves. Parameter studies are carried out to highlight the effects of surface vessel motions on the lateral dynamics of the structures. Example results of displacements, bending stresses are compared for various in water depth, environmental condition and vessel motion. Some instability conditions of the structures due to time-varying tension by vessel heave motion are discussed through the example analyses. As the results, the interaction between vessel surge and heave motions amplifies the total structural response of a riser. In the case of a tether, the effect of vessel heave motion during heavy storm is seemed to be quite significant to lateral response of the structure.

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.564-569
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• 2010

Highly anti-reflective optical property has been focussed in the field of thin film and display because of increasing demands to the high transparency and clearness of optical component. In this study, to obtain anti-reflective property, the formation of aluminium oxide with nanoscaled flowerlike frame structure was introduced as oxide material monolayer on the substrate by hydrothermal synthesis through sol-gel method. The properties of coating layer were measured by the means of UV-Vis spectroscopy, FT-IR spectroscopy, XRD, and FE-SEM. The morphology of coating layer in alumina-sol coated samples was controlled by hydrothermal temperature and time with aid of ultrasound. It was found that high transparency and anti-reflective optical properties were obtained the formation of flowerlike nanoframe structure.

• Journal of Korean Society of Steel Construction
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• v.14 no.4
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• pp.489-497
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• 2002

Nonlinear behavior and large deformation cannot be analyzed using techniques based on linear theory. Nonetheless, they are emerging as gradually huge and complex structures. In addition, the optimum design of structure is necessary in the development of high-performance computation and numerical methods. as well as stricter design-criterion. Therefore, the structural problems in engineering that are limited to the linear region must be extended to the nonlinear region. Likewise, structural behavior must be accurately analyzed. In turn, this requires considering the expected problems beforehand. Only then can an efficient, economical, and optimized structure be designed. This paper presents the solution of the geometrical nonlinear problem of anisotropic cylindrical shell. The characteristics of the geometrical nonlinear behavior of anisotropic circular cylindrical shells may vary according to several causes. e.g., change of fibers, curvature in the circumferential direction, subtended angle, aspect, etc. Parametric studies were conducted to determine the effect of factors on the large deflection behavior of laminated shells, with interesting observations.

• Korean Journal of Medicinal Crop Science
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• v.9 no.4
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• pp.259-264
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• 2001

This experiment was conducted to examine the seed structure and to investigate the changes of seed vigor and germinability according to storage condition of Astragalus membranaceus. In case of the hard seed, there observed a gap between a testa and an embryo with abnormal shapes of an hilum and its micropyle. Seeds stored at room temperature maintained vitality for 4 months but continued to lose its vitality, while increase the hand seeds ratio as storing time longer. The content of Ca increased in proportion to the length of storing time.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.4
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• pp.371-379
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• 2015

This paper represents the structural design of the light weight axle beam for medium duty commercial vehicle using hot press. To reduce the weight of the axle, axle beam of solid type was replaced by hollow type which was made by hot press. According to the change of axle beam structure and manufacturing method, we have to investigate the structural strength and fatigue performance. To verify the axle beam performance, the structural analysis was carried out by simplified axle beam model and various design parameters that are axle beam height, thickness and width. From the analysis results, the light weight axle beam structure was founded and applied the full model analysis. This study will be used as a guidance in development of the light weight axle for medium duty commercial vehicle.