• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.9
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• pp.708-713
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• 2013

KARI is developing a solar-electric powered HALE UAV(EAV-3). For demonstrating the technology, EAV-2H, a down-scaled version of EAV-3, is developed and after EAV-2H's initial flight test, the directional stability and control need to be improved. Thus, the vertical tail and rudder of EAV-2H are redesigned with Advanced Aircraft Analysis(AAA). Size of the rudder is increased from mean chord ratio of rudder to vertical tail, $C_r/C_v(%)=30$ to $C_r/C_v(%)=60$ and size of the vertical tail is reduced 15%. As a result, the directional control to side wind($v_1$) is improved to sideslip angle, ${\beta}(deg)=25^{\circ}$ and $v_1(m/sec)=3.54$. Also, variation of airplane side force coefficient with sideslip angle ($C_{y_{\beta}}$) and variation of airplane side force coefficient with dimensionless rate of change of yaw rate ($C_{y_r}$) are reduced 15% and 22%, respectively to minimize the effect of side wind. The empennage design of EAV-2H is verified with flight tests and applied to design of KARI's solar-electric-powered EAV-3.

• Physical Therapy Korea
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• v.11 no.2
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• pp.35-45
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• 2004

The purpose of this study was to investigate the correlation and characteristics between electromyographic (EMG) activities of lower leg muscles and the posturographic assessment of static balance control in normal adults. Twenty-four young, healthy adults(12 males, 12 females) participated in the study. Center of pressure (COP) parameters were obtained using force platform as total path distance, total sway area, X mean frequency and Y mean frequency for 20 seconds in the following conditions: (1) comfortable standing with eyes opened or closed, (2) uncomfortable standing (feet together) with eyes opened or closed, (3) virtual moving surround delivered using Head mount display (HMD) with four different moving patterns. The virtual moving patterns consisted of close-far, superior-inferior tilting (pitch), right-left tilting (roll), and horizontal rotation (yaw) movements. Surface electromyographic activites were recorded on the tibialis anterior, peroneus longus, medial and lateral heads of gastrocnemius muscles under each condition. Correlation between the posturographic measures and EMG activities were evaluated. Total path distance and total sway area of COP were significantly increased during uncomfortable standing. EMG activity of tibialis anterior was significantly more during uncomfortable standing and virtual moving surround stimulation than during comfortable standing. Total path distance and sway area of COP during comfortable standing with closed eyes showed significant positive correlation with the EMG activities of the lateral head of gastrocnemius muscle. Total path distances and total sway area of COP during muscle. Total path distances and total sway area of COP during presentation of virtual moving surround also had significant positive correlations with EMG activities of the lateral head of gastrocnemius muscle under close-far movement.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.2
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• pp.193-201
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• 2014

This study provided safe sailing speed and appropriate passing time to areas of known strong current water to prevent marine accident of the ships. To the interpretation of these data which target Myeongnyang waterway, AIS data of the ship was collected from $12^{th}$ July to $15^{th}$ July 2010 and site environment was investigated on $4^{th}$ September 2010. On the basis of the collected data, the 'Minimum Navigation Speed' and 'Optimum Navigation Speed' were calculated. It has also considered the 'Spare control force' or allowance and the 'Respond Rudder Angle' for each tidal current speed. Additionally, it suggested the safe passing time to strong current area by analyzing tidal level and tidal current speed. The conclusion of the research are as follows : (1) If the flow rate is greater than 4.4 kn, it is difficult for the model ship to control herself by her own steering power and to cope with tidal current pressure force and yaw moment caused by the tidal current.. (2) The minimum navigation speed should be over 2.3 times the tidal current and the optimum navigation speed should be over 4.0 times the tidal current. (3) When spring tide, the optimum passing time at Myeongnyang waterway is between 30 minutes to 1 hour before the time of high/low water, and at 5 hours after high/low water, passing of ships should be avoided because it is time when the flow rate is over 4 kn.

• Food Science of Animal Resources
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• v.26 no.4
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• pp.411-417
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• 2006

This study was conducted to evaluate the physicochemical properties of pork loin marinated with a solution of Nan and sodium tripolyphosphate, and the sensory attributes of tomato sauce-stewed products using marinated loin. Pork loin samples were cut $(3{\times}3{\times}2cm)$ and assigned to 3 treatment groups [C; unmarinated control (100% distilled water), T1; 10% sodium chloride, T2; 10% sodium chloride + 3% sodium tripolyphosphate]. Samples were marinated for 24hr at $5^{\circ}C$. The uptake of marinade in the treatment groups was significantly greater (p<0.05) than that of C, however no significant difference between the two treatments was observed. Cooking losses were highest (p<0.05) for T1, while lowest (p<0.05) for T2. All marinated loins had a significantly higher (p<0.05) yield than the control. The pH of the marinade solution ranged from 7.00 for T1 to 8.47 for T2. The two marinated loins had a significantly higher (p<0.05) $pH_{24}$ than the control. The water holding capacity (WHC) was highest for T2, and lowest for T1. CIE $L^*,\;a^*,\;b^*$ tended to be slightly higher in the control than either treatment group. The shear force value $(kg/cm^2)$ of yaw meat did not differ between the control and marinated muscle samples. However, cooked meat had a significantly lower (p<0.05) shear force value in T2 than C and T1. Hardness values were significantly lower (p<0.05) for both treatments compared with the control. There were no differences in texture profile, except hardness, between the control and the two treatments. Regarding the sensory evaluation of tomato sauce-stewed products manufactured with marinated pork loin, the treatment groups scored marginally well in tenderness, juiciness and overall acceptability, while the flavor score of the control was significantly higher than those of T1 and T2.