• Korean Journal of Environmental Biology
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• v.25 no.3
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• pp.228-238
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• 2007

Calcium plays an important role for the organisms' physiology, reproduction, and growth. Calcium amount and transfer efficiency along trophic levels were compared at two different geological areas, Limestone area (LS) and Granitic Gneiss area (GG) in 1992 and 1993. Biomass and calcium amount of plants, herbivores and carnivores were seasonally measured. The removal sweeping net method was used to collect the quantitative insect samples. Calcium content (mgCa $g^{-1}$ DM) and pH of soil were 4.85 and 7.3 at LS and 0.21 and 7.3 at GG. The calcium transfer efficiencies (%) at LS and CG were 0.2 and 4.2 from soil to plants, 0.002 and 0.02 from plants to herbivores, and 73 and 47 from herbivores to carnivores, respectively. As a whole, the high calcium content of the LS soil reduced the utilization of calcium by plants. The higher trophical levels were, the higher ecological efficiency of the biological levels was. The calcium transfer amount was higher at LS, but its efficiency was rather higher at GG.

• Korean Journal of Plant Resources
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• v.33 no.6
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• pp.689-695
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• 2020

This study was conducted to improve and supplement the system of cryopreservation for adventitious bulbs induced by tissue cultured bulb-scales of lily (Lilium spp.) cvs. 'Milky way'. The explants, bulblets and bulb-scale-bulblets, were treated to low temperature (4℃) for 7 days prior to the pre-culture. The adventitious bulbs were pre-cultured in Murashige and Skoog (MS) liquid medium supplemented with sucrose (0.3 and 0.7M). The pre-cultured adventitious bulbs were treated to loading solution (LS1 or LS2, C4 or C6) containing 35% of PVS3 (LS1, C4) or 40% of PVS3 (LS2, C6) for 40 min and exposed to dehydration solution (PVS3, B1) containing 50% glycerol and 50% sucrose for 60 min at 25℃. The adventitious bulbs were moved onto droplets containing 3 µl PVS3 on sterilized aluminum foils, and then soaked into liquid nitrogen (LN) for 60 min. The result of highest regrowth rate as 65.7% was obtained in cold treatment (4℃), osmoprotected with LS1 solution, and cultured in PCM3 medium by using bulb-scale-bulblet for cryopreservation. This result shows that droplet-vitrification could be used as a promising method for long-term storage of lily genetic resource.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1793-1794
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• 2007

Since it has an advantage of possibility to control using experimentally given coefficient, PID Control is the most widely used method of control in the field of industry. However, since PID controller is not able to reflect the inherent characteristics of individual systems, it needs to be accompanied by additional techniques to supplement. Also, it has disadvantage that it is hard to find a satisfactory coeffi cient when the state of the system's dynamic characteristics and static characteristics are different each other. When the dynamic one shows up, it means the state of system shows a great amount of difference from that of desired such as the moment of beginning control or change of desired state. But, if the state of the system comes close to the desired state, the static characteristics shows up in the system. There are many solutions suggested to overcome problems according to the conversion of two examples of motion shown above. This paper is to confirm PID control's integration ingredient windup phenomenon, and experiment through technique of pre vention of windup actually using PLC(Programmable Logic Co ntroller), and to verify the change in characteristics of control.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.35-35
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• 2021

This study was conducted to improve and supplement the system of cryopreservation for adventitious bulbs induced by tissue cultured bulb-scales of lily (Lilium spp.) cvs. 'MilkyWay'. The explants, bulblets and bulb-scale-bulblets, were treated to low temperature (4℃) for 7 days prior to the pre-culture. The adventitious bulbs were pre-cultured in Murashige and Skoog (MS) liquid medium supplemented with sucrose (0.3 and 0.7M). The pre-cultured adventitious bulbs were treated to loading solution (LS1 or LS2, C4 or C6) containing 35% of PVS3 (LS1, C4) or 40% of PVS3 (LS2, C6) for 40 min and exposed to dehydration solution (PVS3, B1) containing 50% glycerol and 50% sucrose for 60 min at 25℃. The adventitious bulbs were moved onto droplets containing 3 ㎕ PVS3 on sterilized aluminum foils, and then soaked into liquid nitrogen (LN) for 60 min. The result of highest regrowth rate as 65.7% was obtained in cold treatment (4℃), osmoprotected with LS1 solution, and cultured in PCM3 medium by using bulb-scale-bulblet for cryopreservation. This result shows that droplet-vitrification could be used as a promising method for long-term storage of lily genetic resource.

• Journal of IKEEE
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• v.24 no.1
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• pp.260-268
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• 2020

This paper presents the high frequency resonant inverter of class D SEPP(Single-Ended Push Pull) type using LS-ZVS-LSTC, which can reduce the switching losses during the turn-on and turn-off switching time. The analysis of high frequency resonant inverter using LS-ZVS-LSTC(Low-loss Turn-off Snubber Capacitor) proposed in this paper is described in general by adopting the normalized parameters. The operating characteristics of the proposed high frequency resonant inverter were also evaluated by using the control parameters such as the normalized control frequency(μ), the normalized load time constant(τ), the coupling factor(κ) and so on. Based on the characteristic values through the characteristics of evaluation, an example of the design method of the 1.8[kW] class D SEPP type high frequency inverter is suggested, and the validity of the theoretical analysis is verified using the experimental data.

• The Korean Journal of Nuclear Medicine
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• v.39 no.1
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• pp.21-25
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• 2005

Purpose: $^{14}C$-urea breath test (UBT) is a non-invasive and reliable method for the diagnosis of Helicobacter pylori (HP) infection. In this study, we evaluated the diagnostic performance of a new and rapid $^{14}C$-UBT (Heliprobe method), which was equipped with $Geiger-M\ddot{u}ller$ counter and compared the results with those obtained by using the conventional method. Materials and Methods: Forty-nine patients with dyspepsia underwent gastroduodenoscopy and $^{14}C$-UBT. A 37 KBq $^{14}C$-urea capsule was administered to patients and breath samples were collected. In Heliprobe method, patients exhaled into a Hellprobe BreathCard for 10 min. And then the activities of the BreathCard were countered using Heliprobe analyzer. In the conventional method, results were countered using liquid scintillation counter. During gastroduodenoscopy, 18 of 49 patients were underwent biopsies. According to these histologic results, we evaluated the diagnostic performance of two different methods and compared them. Also we evaluated the concordant and disconcordant rates between them. Results: In all 49 patients, concordant rate of both conventional and Heliprobe methods was 98% (48/49) and the discordant rate was 2% (1/49). Thirteen of 18 patients to whom biopsies were applied, were found to be HP positive on histologic results. And both Heliprobe method and conventional method classified 13 of 13 HP-positive patients and 5 of 5 HP-negative patients correctly (sensitivity 100%, specificity 100%, accuracy 100%). Conclusion: The Heliprobe method demonstrated the same diagnostic performance compared with the conventional method and was a simpler and more rapid technique.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.5
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• pp.364-371
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• 2021

A magnetic flux saturation model of Synchronous Reluctance Motors (SynRMs) and a parameter estimation method are proposed at standstill. The proposed magnetic flux model includes the nonlinear relationship between the current and the magnetic flux for self-saturation and cross-saturation. Voltage is injected at standstill to estimate the magnetic flux saturation model. Voltages are injected into the d-axis and q-axis to obtain data on self-saturation. Subsequently, voltages are simultaneously injected into the d-q axis to obtain data on cross-saturation. On the basis of the measured current and the calculated magnetic flux, the parameters of the proposed model are estimated using the least square method (LSM). Simulation and experiment were performed on a 1.5-kW SynRM to verify the proposed method. The proposed model can be used to create a high-efficiency operation table, a sensorless algorithm, and a current controller to improve the control performance of a motor.

• The Journal of the Acoustical Society of Korea
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• v.29 no.6
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• pp.374-380
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• 2010

It is known that the problem of FIR filtering with noisy input and output data can be solved by a total least squares (TLS) estimation. It is also known that the performance of the TLS estimation is very sensitive to the ratio between the variances of the input and output noises. In this paper, we propose a convex combination algorithm between the ordinary recursive LS based TLS (RTLS) and the ordinary recursive LS (RLS). This combined algorithm is robust to the noise variance ratio and has almost the same complexity as the RTLS. Simulation results show that the proposed algorithm performs near TLS in noise variance ratio ${\gamma}{\approx}1$ and that it outperforms TLS and LS in the rage of 2 < $\gamma$ < 20. Consequently, the practical workability of the TLS method applied to noisy data has been significantly broadened.

• International Journal of Highway Engineering
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• v.18 no.4
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• pp.63-68
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• 2016

PURPOSES : The nonlinear model of fatigue cracking is typically used for determining the maintenance period. However, this requires that the model parameters be known. In this study, the particle filter (PF) method was used to determine various statistical parameters such as the mean and standard deviation values for the nonlinear model of fatigue cracking. METHODS : The PF method was used to determine various statistical parameters for the nonlinear model of fatigue cracking, such as the mean and standard deviation. RESULTS : On comparing the values obtained using the PF method and the least square (LS) method, it was found that PF method was suitable for determining the statistical parameters to be used in the nonlinear model of fatigue cracking. CONCLUSIONS : The values obtained using the PF method were as accurate as those obtained using the LS method. Furthermore, reliability design can be applied because the statistical parameters of mean and standard deviation can be obtained through the PF method.

• Journal of Ocean Engineering and Technology
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• v.27 no.5
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• pp.70-76
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• 2013

The present paper proposes a coupled volume-of-fluid (VOF) and level-set (LS) method for simulating incompressible two-phase flows that include surface tension effects. The interface of two fluids and its motion are represented by a VOF method designed using high-resolution differencing schemes. This hybrid method couples the VOF method with an LS distancing algorithm in an explicit way to improve the calculation of the normal and curvature of the interface. It is developed based on a rather simple algorithm to be efficient for various practical applications. The accuracy and convergence properties of the method are verified in a simulation of a single gas bubble rising in a three-dimensional flow with a large density ratio.