• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1674-1680
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• 2008

The objective of this study is to compare age-related differences of 15 characteristic variables estimated from SEMG signals, which were obtained from the old group(62 subjects) and young group(72 subjects). The SEMG signals were recorded from biceps brachii muscle under sustained isometric elbow flexion contraction with constant load(4kg dumbbell) during 30 seconds. Ten time domain (ARV, RMS, MSA, MTA, ZC, MSF, MTF, MSD, MTD, MSS) and five frequency domain(MNF, MDF, $f_{max}$, $P_{max}$, $P_{to}$) variables were extracted from the SEMG signals and then statistically analyzed, respectively. The findings of the analysis indicate significant age-related differences in the SEMG signal during constant load contraction.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.6
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• pp.284-289
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• 2002

The transmission networks do not consist of perfect conductors and a percentage of the power generated is therefore lost before it reaches the loads. Since this network loss contributes to the cost of suppling power to consumers, it must be considered that the most efficient dispatch and location of generators and loads are to be achieved. In this paper, marginal loss factors are calculated for 12 load levels that represent the impact of marginal network losses on nodal prices at the transmission network connection points at which generators are located. Based on comparison analysis of marginal loss factors on 12 load levels, we found the MLF characteristics in KOREA.

• Structural Engineering and Mechanics
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• v.39 no.2
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• pp.287-301
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• 2011

This paper is focused on the residual capacity of steel columns, as a damage criterion. Load-Impulse (P-I) diagrams are frequently used for analysis, design, or assessment of blast resistant structures. The residual load carrying capacity of a simply supported steel column was derived as a damage criterion based on a SDOF computational approach. Dimensionless P-I diagrams were generated numerically with this quantitative damage criterion. These numerical P-I diagrams were used to show that traditional constant ductility ratios adopted as damage criteria are not appropriate for either the design or damage assessment of blast resistant steel columns, and that the current approach could be a much more appropriate alternative.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.427-432
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• 2003

The control method of programmable dynamometer for overall test of machine is to load the reference torque which is computed from torque transducer into motor under test. But the torque information detected from torque transducer have a lot of noise when the load torque of moter is a small quantity or changing. Thus, torque transducer must have a low pass filter to detect a definite torque information. But The torque delay generated by filter with torque transducer occur a torque trouble for meter torque of programmable dynamometer. The proposed system improved the problem of the torque measuring delay with torque transducer, and the load torque is estimated by the minimal order state observer based on the torque component of the vector control induction meter. Therefore, the torque controller is not affected by a load torque disturbance.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.1
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• pp.6-12
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• 2007

In this paper, an robust adaptive backstepping controller is proposed for the speed control of separately excited DC motor in pure electric vehicles. A general electric drive train of PEV is conceptually rearrange to major subsystems as electric propulsion, energy source, and auxiliary subsystem and the load torque is modeled by considering the aerodynamic, rolling resistance and grading resistance. Armature and field resistance, damping coefficient and load torque are considered as uncertainties and noise generated at applying load torque to motor is also considered. It shows that the backstepping algorithm can be used to solve the problems of nonlinear system very well and robust controller can be designed without the variation of adaptive law. Simulation results are provided to demonstrate the effectiveness of the proposed controller.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.977-979
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• 1996

This paper presents an algorithm to control the undesirable sway of a suspended load in the crane system that has a trade-off between positioning the load and suppressing the sway of the load. The aim is to transport the load to a specified place with small sway angle as quickly as possible. Dynamic model is based on a simple pendulum driven by a velocity drive that is mostly used for actuating a trolley in industry. Proposed algorithm is composed of two parts : one is a off-line optimal trajectory generator, the other on-line tracking control. The former produces optimal trajectories minimizing energy under the speed constraint of velocity drive. The latter controls outputs to track the generated trajectories. Digital simulations and experiments are performed on a pilot crane to demonstrate the performance of the proposed control algorithm.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1108-1110
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• 2003

The control method of programmable dynamometer for overall test of machine is to load the reference torque which is computed from torque transducer into motor under test. But the torque information detected from torque transducer have a lot of noise when the load torque of meter is a small quantity or changing. Thus, torque transducer must have a low pass filter to detect a definite torque information. But The torque delay generated by filter with torque transducer occur a torque trouble for meter torque of programmable dynamometer. The proposed system improved the problem of the torque measuring delay with torque transducer, and the load torque is estimated by the minimal order state observer based on the torque component of the vector control induction moter. Therefore, the torque controller is not affected by a load torque disturbance.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.1
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• pp.142-148
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• 2014

The mirror which is considered in designing a MFD is off-axis primary one and its dimension is wide 556mm height 345mm. The MFD(Mirror Fixation Device) load specification is generated for the high resolution mirror. The optical WFEs for unit loads are calculated from mirror sensitivity analysis and they are compared with allocated allowable optical WFE. The parasite load for the MFD is calculated from their comparison. The MFD compliant with the parasite load is designed.

• Journal of Korean Association for Spatial Structures
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• v.21 no.1
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• pp.51-59
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• 2021

In this paper, the effect of the turbulence intensity in across-wind direction on the wind load in CFD(Computational fluid dynamics) simulation was analyzed. 'Ansys fluent' software was used for CFD simulation. And the fluctuating wind speed applied to the simulation was generated according to Korean Design Standard and Von Karman wind turbulence model. The turbulence intensity in across-wind direction for simulation was applied from 0 to 100% of the turbulence intensity in along-wind direction. The analysis results showed that the turbulence intensity in across-wind direction had a particularly great effect on the wind load in across-wind direction.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.5
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• pp.345-356
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• 2017

We investigated 52 livestock farming complexes in Gyeong-Gi and Incheon provinces based on low, medium, and high livestock density and groundwater quality. The objective of this study was to evaluate a relationship between nitrate N concentration in groundwater and animal factors, such as livestock density and animal species. 2,200 groundwater samples for 3 years from 2012 to 2014 at Gyeong-Gi and Incheon provinces were collected and analyzed for pH, EC, DO, ORP, temperature, major anions and cations, such as $NO_3-N$, ${HCO_3}^-$, ${PO_4}^-$, ${SO_4}^{2-}$, $Cl^-$, $NH_4-N$, $K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$, T-N, and TOC. Average concentration of total N for generated load density was $23,973g\;day^{-1}\;km^{-2}$ for cattle, $51,551g\;day^{-1}\;km^{-2}$ for pig, and $52,100g\;day^{-1}\;km^{-2}$ for poultry. For animal feeding species, average ratio for generated load over discharge load was 16.1% for cattle, 7.8% for pig, and 7.1% for poultry. Therefore, cattle feeding region is highly vulnerable for water pollution compared to pig and poultry feeding areas. The concentrations of chloride, nitrate, and total N in the groundwater samples were higher at high animal farming regions than other regions. The average concentration of nitrate, and chloride in groundwater samples was $5.0mg\;L^{-1}$, $16.6mg\;L^{-1}$ for low livestock density, $6.9mg\;L^{-1}$, $17.7mg\;L^{-1}$ for medium livestock density and $7.6mg\;L^{-1}$, $22.7mg\;L^{-1}$ for high livestock density and total nitrogen (T-N) was $7.7mg\;L^{-1}$ for low livestock density, $9.4mg\;L^{-1}$ for medium livestock density, $10.7mg\;L^{-1}$ for high livestock density. In conclusion, based on this research, for managing groundwater quality near livestock farming regions, $Ca-(Cl+NO_3)$ group from the Piper diagram is more efficient than using 19 factors for water quality standard.