• Spatial Information Research
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• v.12 no.2
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• pp.181-191
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• 2004

Nowadays, GPS-photogrammetry can be applied to the basemap production, a land register and NGIS. And from now on, as the increase of GPS receiver rate, the study on the interpolation methods considering the exact movement of an aircraft at photoflight and the study on the supplement of GPS defect by INS are required continuously. GPS-Photogrammetry, which are based on the direct measurement of the projection centers and attitude at the moment of camera exposure time through loading the GPS receiver in aircraft. This photogrammetric methods can of for us to acquire the exterior orientation parameters with only minimum ground control points, even the ground control process could be completely skipped. Consequently, we can drastically reduce the time and cost far the mapping process. In this thesis, two test flights were conducted in area to evaluate the performance of accuracy and efficiency through the analysis of results between the two photogrammetric methods, that is, traditional photograrammetry, GPS-Photogrammetry. Test results shows that a large variety of advantages of GPS-Photogrammetry against traditional photogrammetry is to be verified. Especially, the number of ground control points for the exterior orientation could be saved more than 70～80%, and the cost far map production 30～50%, respectively. In addition, it was convinced that the large reduction of control points has not any effect on the block accuracy.

• Journal of Bio-Environment Control
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• v.25 no.3
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• pp.146-152
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• 2016

Due to complicate canopy structures of Irwin mangoes grown in greenhouses, it is difficult to determine their growth parameters accurately. Leaf area, leaf fresh weight, and leaf dry weight are widely used as indicators to diagnose the tree growth. Therefore, it is necessary to establish models that can non-destructively estimate these growth indicators. The objective of this study was to establish regression models to estimate leaf area, leaf fresh weight, and leaf dry weight of Irwin mangoes (Mangifera indica L. cv. Irwin) by using leaf length, leaf width, petiole length, and SPAD value. The input values of leaf length, leaf width, petiole length, and SPAD value of 6-year old Irwin mangoes were measured, and the corresponding output values of leaf area, leaf fresh weight, and leaf dry weight were also measured. After 14 models were selected among the existing models, coefficients of the models were estimated by regression analysis. Three models with higher $R^2$ and lower RMSE values selected. In validation the $R^2$ values for the selected models were 0.967, 0.743, and 0.567 in the leaf area, leaf fresh weight, and leaf dry weight models, respectively. It is concluded that this models will be helpful to conveniently diagnose the growth of the Irwin mango.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.768-774
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• 2010

A parametric study is conducted for the segmented arc plasma torch with the input power and current of 0.4 MW and 300 A, respectively. For this purpose, we use the analytical relationship equations between plasma temperature, inner diameter (R) and length (L) of the torch constrictor at the given input power and current conditions based on the arc channel model. The results reveal that arc plasma temperatures show non-linear behavior or absence corresponding to the variations of L and R when their values become larger than 1.25 m and 7.5 mm, respectively. For L < 1.25 m and R < 7.5 mm, however, they can increase monotonically as L increase or R decrease when one of both parameters is fixed. From these parametric study results, optimum ranges of R and L are suggested as $5.5mm{\leq}R{\leq}7.0mm$ and $0.5m{\leq}L{\leq}1.0m$ for 0.4 MW class segmented arc plasma torch, under which stable arc plasma with the temperatures of ~15,000 K can be achived at the input currents of ~300 A.

• Geomechanics and Engineering
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• v.21 no.1
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• pp.23-33
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• 2020

An advancing cutting roof for gob-side entry retaining with no-pillar mining under specific geological conditions is more conducive to the safe and efficient production in a coalmine. This method is being promoted for use in a large number of coalmines because it has many advantages compared to the retaining method with an artificial filling wall as the gateway side filling body. In order to observe the inner structure of the gateway cutting roof and understand its stability mechanism, an equivalent material simulation experiment for a coalmine with complex geological conditions was carried out in this study. The results show that a "self-stabilization bearing structure" equilibrium model was found after the cutting roof caving when the cut line deviation angle was unequal to zero and the cut height was greater than the mining height, and the caving roof rock was hard without damage. The model showed that its stability was mainly controlled by two key blocks. Furthermore, in order to determine the optimal parameters of the cut height and the cut line deviation angle for the cutting roof of the retaining gateway, an in-depth analysis with theoretical mechanics and mine rock mechanics of the model was performed, and the relationship between the roof balance control force and the cut height and cut line deviation angle was solved. It was found that the selection of the values of the cut height and the cut line deviation angle had to conform to a certain principle that it should not only utilize the support force provided by the coal wall and the contact surface of the two key blocks but also prevent the failure of the coal wall and the contact surface.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.799-804
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• 2016

Broadband powerline communication (BPLC) uses distribution lines as a medium for achieving effective bidirectional data communication along with electric current flow. As the material characteristics of power lines are not good at the communication channel, the development of power line communication (PLC) systems for internet, voice, and data services requires measurement-based models of the transfer characteristics of the network suitable for performance analysis by simulation. In this paper, an analytic model describing a complex transfer function is presented to obtain the attenuation and path parameters for a multipath power line model. The calculated results demonstrated frequency-selective fading in multipath channels and signal attenuation with frequency, and were in good agreement with the experimental results. Inductive coupling units are used as couplers for coupling the signal to the power line to avoid physical connections to the distribution line. The inductance of the ferrite core, which depends on the frequency, determines the cut-off frequency of the inductive coupler. Coupling loss can be minimized by increasing the number of windings around the coupler. Coupling efficiency was improved by more than 6 dB with three windings compared to the results obtained with one winding.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.3
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• pp.307-313
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• 2010

In this study, alternative designs for the bends used in district heating pipes are investigated. The district heating pipes, which are subjected to temperatures of 10 to $120^{\circ}C$ and a water pressure of $16\;kgf/cm^2$, have to withstand thermomechanical cyclic loads when in use. These pipes comprise three concentric tubes: a steel pipe (internal), polyurethane (PUR) insulator (middle), and a high-density polyethylene (HDPE) case (external). In addition, the bends in the district heating pipe system are covered with foam pads that cause aging. In this study, an alternative bend design that does not involve the use of a foam pad is proposed to overcome the aging problem in the bends. In the proposed design, "shear rings" are added to the surface of a bend, and its dimensions are determined by a combination of the statistical (Taguchi) method and FEM. The geometrical parameters such as thickness, height, and number of the rings significantly affect the design optimization, and hence, they affect the results of the FEM.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.4
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• pp.234-243
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• 1992

Fatigue crack initiation life has a wide scatter and this makes the fatigue design of structural members difficult. In order to make the fatigue life distribution clear, it is required to prepare a large number of specimens and repeat the fatigue tests under the same loading condition. Such fatigue tests usually take much time and cost. In this study, a fatigue testing method using a multi-notched test specimen for the purpose of estimating the distribution function of fatigue crack initiation life by small number of fatigue tests is used. The purpose of this study is to verify the above fatigue testing method of a multi-notched specimen by using Bayesian reliability analysis, Least square method and Skewness method for the determination of unknown Weibull parameters. The multi-notched specimen is a specimen in which several tens of statistically identical notches are prepared.

• Food Science and Preservation
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• v.18 no.4
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• pp.517-526
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• 2011

The physical properties of dough with different levels (2, 4, 6, and 8%) of bamboo leaf powder were inverstigated. The bamboo leaf powder had a moisture content of 5.15%, a crude protein content of 10.48%, a crude fat content of 5.21%, a crude fiber content of 22.74%, and a crude ash content of 17.63%. The following parameters showed significant differences with the increase in the amount of bamboo leaf powder added. The gelatinization degree measured by a rapid visco-analyzer increased with the increase in the powder amount added. In the values of the farinogram parameter for dough consistency, the elasticity of the dough increased with the increase in the powder amount added. The alveogram values showed a similar tendency as those of the farinogram in terms of elasticity, absorption rate, absorption time and stability. In the rheofermentometer analysis, the volume decreased with the increase in the powder amount added, but no significant difference was found at up to 4% powder amount addition, suggesting that the about 2% and up to 4% powder amount addition is moderate.

• International Journal of Oral Biology
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• v.39 no.2
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• pp.97-105
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• 2014

The aim of this study was to determine the beneficial effect of propofol on human keratinocytes that have undergone hypoxia reoxygenation (H/R) injury and to investigate whether autophagy is associated with the protective mechanism. Thus, we evaluated how propofol influences the intracellular autophagy and apoptosis during the H/R process in the HaCaT cells. The cultured human keratinocyte cells were exposed to 24 h of hypoxia (5% $CO_2$, 1% $O_2$, 94% $N_2$) followed by 12 h of reoxygenation (5% $CO_2$, 21% $O_2$, 74% $N_2$). The experiment was divided into 4 groups: (1) Control=Normoxia ; (2) H/R=Hypoxia Reoxygenation ; (3) PPC+H/R=Propofol Preconditioning+Hypoxia Reoxygenation; (4) 3-MA+PPC+ H/R=3-MA-Methyladenine+Propofol Preconditioning+ Hypoxia Reoxygenation. In addition, Western blot analysis was performed to identify the expression of apoptotic pathway parameters, including Bcl-2, Bax, and caspase 3 involved in mitochondrial-dependent pathway. Autophagy was determined by fluorescence microscopy, MDC staining, AO staining, and western blot. The H/R produced dramatic injuries in keratinocyte cells. In our study, the viability of Propofol in H/R induced HaCaT cells was first studied by MTT assay. The treatment with 25, 50, and $100{\mu}M$ Propofol in H/R induced HaCaT cells enhanced cell viability in a dose-dependent manner and $100{\mu}M$ was the most effective dose. The Atg5, Becline-1, LC3-II, and p62 were elevated in PPC group cells, but H/R-induced group showed significant reduction in HaCaT cells. The Atg5 were increased when autophagy was induced by Propofol, and they were decreased when autophagy was suppressed by 3-MA. These data provided evidence that propofol preconditioning induced autophagy and reduced apoptotic cell death in an H/R model of HaCaT cells, which was in agreement with autophagy playing a very important role in cell protection.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.5
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• pp.485-493
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• 2007

Purpose: Heart rate variability(HRV) is the clinical consequence of various influences of the autonomic nervous system(ANS) on heart beat. HRV can estimate the potential physiologic rhythm from the interval between consecutive beats(RR interval or HRV data). It is known as RSA which represents respiration-related HR rhythmic oscillation. Previous studies demonstrated a specific breathing pattern(0.1Hz, 6breaths/min) to improve a physiological body condition related to the stress. In this paper, the level of stress would be evaluated in terms of three phases of the dental treatment, combined with 6breaths/min. Methods: These phases include before, during and after tooth extraction or anesthesia or something.36 patients' stresses were assessed using HRV stress analyzer in each phase in Kangdong Sacred Heart Hospital, and Chuncheon Sacred Heart Hospital, Hallym University Medical Center from Jun. to Sept. of 2007. HRV 5-min data collected were analyzed in time-domain and frequency-domain to evaluate the activity of autonomic nervous system(ANS) which represents the level of stress. Results: All HRV parameters including HF(high frequency), LF(low frequency) and LF/HF ratio showned a significant change affecting the ANS balance. There was a 6.4% difference between R(LF/HF)s on general breathing pattern for balance of Autonomic nervous system, but on controlled breathing pattern, 0.1Hz, was made narrow till 1.4%. The activity of ANS has increased by 1.4% on general breathing pattern, and by 2.9% on controlled breathing pattern, 0.1Hz. Conclusion: After analysis of preoperative stress changes and effect of breathing pattern of 0.1 Hz on the stress in 36 patients who have undergone third molar extraction, following was concluded. In the preoperative stage, the sympathetic change was the greatest?after the?anesthetic injection, and stress was relieved by controlling the breathing pattern to a frequency of 0.1Hz.