• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.69-78
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• 2006

High spectral efficiency can be obtained by adaptive modulation in which the modulation scheme is changed according to the channel environment. Thus it is especially suitable to mobile channel which is a typical example of time-varying channel. It is required to determine the optimum thresholds of signal-to-noise ratio(SNR) to change the modulation scheme effectively according to mobile speeds. Thus the optimum thresholds for specific mobile speeds to get the required bit error rate(BER) of $10^{-6}$ are obtained with the powerful turbo code in this paper. In addition, the optimum thresholds for the continuous mobile speed are proposed by interpolation of the obtained results. And the error performance and average spectral efficiency are investigated at various mobile speeds and channel environments.

• Journal of the Korea Concrete Institute
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• v.19 no.3
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• pp.301-312
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• 2007

A slab-column connection is susceptible to brittle punching shear failure, which may result in the necessity of shear reinforcement. In the present study, to investigate the earthquake resistance of newly developed lattice shear reinforcement, experimental study was performed for interior slab-column connections subjected to cyclic loading. For comparison, specimens with existing shear reinforcement method such as stud rail, shear band and stirrup were also tested. The test result showed that the structural capacity of the lattice shear reinforcement was superior to those of the existing methods and was greater than the code-specified strength. On the other hand, the existing methods did not significantly improve the shear strength of the specimens. The shear strengths of the existing methods were much less than the code-specified shear strength.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.1
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• pp.56-63
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• 2007

A color gamut mapping has been known to be one of promising methods to enhance display quality of various types of color display device. However, it is required to handle this mapping in real time for display or digital TV application. If carefully arranged, the tetrahedral interpolation can be computed with simpler operations compared to a cubic interpolation in the conventional reduced resolution look-up table which is devised to process the gamut mapping in real time. Based on the tetrahedral interpolation, a new type hardware architecture for real-time gamut mapping is proposed in this paper. The proposed hardware architecture shows better processing speed and reduces the hardware cost.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.11
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• pp.1077-1085
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• 2011

Various stakeholder's expectations and constraints are to be efficiently resolved into a program consensus prior to the beginning of its substantial design processes. This study focuses on the analysis of the stakeholder's expectations in determining the design requirements at the initial stage of space exploration programs including Naro launcher and currently on-going KSLV-II program. Naro program seems to unilaterally account for the government expectations of accelerating program phase speed without making any efforts to converge various expectations from related sectors. The planning of Naro launcher is also found lack of the concept of operations (ConOps), which is of critical importance by envisaging the operational applications of end products. Similarities are found in KSLV-II program regarding the lack of implementation for stakeholder's expectations. Moreover, the government plan for KSLV-II disclosed without considering all expectations and other comments. The increase in design conflicts and program uncertainties would be unavoidable, if the government plan for KSLV-II would be insisted. It is required to modify the government plan and to establish the ConOps with the convergence of stakeholder's expectations at this early stage of the program.

• Journal of the Korean Magnetics Society
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• v.17 no.6
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• pp.242-245
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• 2007

Conduction noise attenuation by composite sheets of high magnetic and dielectric loss has been analyzed by using electromagnetic field simulator which employs finite element method. The simulation model consists of microstrip line with planar input/output ports and noise absorbers (magnetic composite sheets containing iron flake particles as absorbent fillers). Reflection and transmission parameters $(S_{11}\;and\;S_{21})$ and power loss are calculated as a function of frequency with variation of sheet size and thickness. The simulated value is in good agreement with measured one and it is demonstrated that the proposed simulation technique can be effectively used in the design and characterization of noise absorbing materials in the RF transmission lines.

• The Korean Journal of Mycology
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• v.12 no.4
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• pp.164-169
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• 1984

Interspecific heterokaryons were obtained between auxotrophic mutants of Pleurotus ostreatus and Pleurotus florida by polyethylene $glycol-Ca^{++}$ induced fusion of somatic protoplasts. The fusion products produced colonies of dense growing mycelium after 10-14 days culture on hypertonic Mushroom Minimal Medium. When they were transferred to Mushroom Minimal Medium plates, the sectors showed normal vegetative morphology but the colonies of irregular shape varied in growth rate. All of the colonies produced fruit body of normal pilei. Some heterokaryon colonies bearing none or only a small amounts of basidiospores were isolated. Fusion products, generally, gave higher basidiocarp yields than the parents.

• Elastomers and Composites
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• v.38 no.3
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• pp.273-280
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• 2003

Elastic responses on both pure natural rubber melts with different molecular weights and the rubber compounds mixed with various types of carbon blacks were investigated in this study. Furthermore, the degree of bound rubber was measured for various carbon blacks with different sizes and structures in order to study the interaction between the rubber and carbon blacks, and to study the correlation between the interaction and the elastic responses. As a loading amount of carbon black increased, the degree of bound rubber became higher, particularly far carbon-black particles with smaller sizes and higher structures. The elastic responses of the rubber melt filled with carbon black remarkably improved, as compared with those of unfilled rubber melt, specially in carbon black showing higher contents of bound rubber. Stress relaxation was more delayed and recovery behavior became more elastic, as the molecular weight of the rubber melt increased and the size of carbon-black particles was decreased. Permanent set became higher, as the molecular weight of the rubber melts decreased and the size of carbon-black particles increased.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.471-473
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• 2018

Variovorax sp. PMC12 is a rhizobacterium isolated from tomato rhizosphere and enhanced the plant resistance to abiotic and biotic stresses. Here we present the complete genome sequence of strain PMC12. The genome is comprised of two circular chromosomes harboring 5,873,297 bp and 1,141,940 bp, respectively. A total of 6,436 protein-coding genes, 9 rRNAs, 64 tRNAs, 3 ncRNAs, and 80 pseudogenes were identified. We found genes involved in 1-aminocyclopropane-1-carboxylate (ACC) deaminase, antioxidant activity, phosphate solubilization, and biosynthesis of proline and siderophore. Those genes may be related to capability of improving plant resistance to various stresses including salinity, cold temperature, and phytopathogen.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.3
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• pp.185-195
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• 2021

The flapping-wing micro air vehicle (FW-MAV) in this study utilizes the cambered wings made of quite flexible material. Similar to the flying creatures, the present cambered wing uses three different materials at its leading edge, vein, and membrane. And it is constrained in various conditions. Since passive rotation uses the flexible nature of the wing, it is important to select an appropriate material for a wing. A three-dimensional fluid-structure interaction solver is developed for a realistic modeling of the cambered wing. Then a parametric study is conducted to evaluate the aerodynamic performance in terms of the elastic modulus of leading edge and vein. Consequently, the elastic modulus plays a key role in enhancing the aerodynamic performance of FW-MAVs.

• Composites Research
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• v.34 no.1
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• pp.51-56
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• 2021

This paper studied the possibility of manufacturing bulk graphite using coal tar, a precursor of coal tar pitch, as a binder and impregnant. Carbonization was conducted after mixing and molding with natural graphite as a filler and coal tar as a binder. Impregnation-recarbonization was performed five times after carbonization. Coal tar used as impregnant. Measuring density, porosity, compressive strength, and anisotropy ratio was conducted. The maximum density of bulk graphite specimen was 1.76 g/㎤ and the minimum porosity was 15.6% which could be controlled by process control. The highest compressive strength was 20.3 MPa. Then the maximum anisotropic ratio of bulk was shown 0.34 through XRD analysis. Therefore, it was confirmed that it was possible to manufacture artificial graphite in a bulk form by using coal tar as a binder and an impregnant.