• FLOWER RESEARCH JOURNAL
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• v.17 no.3
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• pp.185-189
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• 2009

This study was carried out to investigate the effect of shading (50% or not) and pruning height (3cm, 6cm, and 9cm) of remained above-ground plant part on shoot emergence aspect, mortality rate, flowering and cut flower characteristics of two years old Gypsophila paniculata plants. Days to shoot emergence (80%) advanced, emerged shoot number increased and mortality rate surveyed on late October decreased in 50% shading treatment. In addition to, mortality rate decreased, as above-ground plant part was highly pruned. Blooming was earlier with highly pruning the remained above-ground pan and under non-shading condition than shading. Growth traits such flower stalk length, primary branches number, stem diameter, and cut flower yield were the best and also non-particulate rate and rosette formation rate were the lowest in pruning height of 9cm under non-shading condition.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.2
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• pp.76-85
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• 2011

In conventional methods for measuring snow height, a graduated pole is installed on ground in an area of interest and the snow height is manually read from the pole. Recently, automated snow height measurement systems have been introduced to improve the conventional methods. The automated measurement systems, however, are quite expensive since they use the reflection of ultrasonic waves or laser beams. In addition, it is not easy to move the location of the automated measure systems. This paper proposes a snow height measurement system equipped with image sensors and wireless communication capability via a USN and the Internet. The proposed system has a resolution of 5 cm and easy to deploy without difficulties, which can be usefully used to monitor unforseen local snowfalls.

• Korean Journal of Applied Biomechanics
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• v.21 no.2
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• pp.197-205
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• 2011

Various jumping and landing motions are shown during sports event. But most previous studies have not considered landing height and distance simultaneously. The purpose of this study was to identify the effects of landing height and distance on knee injury mechanism. Fourteen male(age: $28.86{\pm}1.99$ yrs, height: $177.00{\pm}4.69$ cm, weight: $76.50{\pm}6.41$ kg) participated in this study. The subjects attempted drop landing task onto the ground from 30 cm to 45 cm heights and to 20 cm to 40 cm distances. The results were as follows. First, higher drop landing height and longer distance showed greater degree of maximal knee flexion and valgus. Second, higher drop landing height and longer distance showed greater maximal knee extension moment and varus moment. Third, higher drop landing height and longer distance showed larger maximal knee absorption power. Lastly, higher drop landing height showed increased Peak GRF. Landing height was more related to the cause of injury, which was indicated by increased maximal knee extension moment, peak GRF and maximal knee absorption power. Landing distance was also associated with increased knee valgus moment and absorption power during landing. These results suggest that landing height and distance may be the cause of injury.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.6
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• pp.1-7
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• 2005

Incompressible Reynolds-averaged Navier-Stokes equations with $\varepsilon{-SST}$ turbulence model are adopted for the investigation of the flow fields between the square cylinder and the ground. When the grounds moves, the diminish of the shear layer intensity on the ground promotes the interaction between the lower and the upper separated shear layer of the cylinder. Hence vortex shedding occurs at the lower gap height than stationary ground. In the moving ground, the secondary shedding frequency disappears due to the absence of the separation bubble on the ground which exists in the stationary ground. In addition, the shedding frequency and aerodynamic coefficients in the moving ground become higher than those of the stationary ground.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.3 s.18
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• pp.93-100
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• 2004

In this paper, we describe the design, fabrication, and test results of a W-band FMCW radar for the metal target detection under the ground clutter environment. In order to detect metal targets on the ground, we used a single cassegrain antenna with the beamwidth of $1.45^{\circ}$ which forms pencil-beam footprint on the ground. A log envelope detector was applied to improve radar performance in the severe ground clutter known as Weibull and log normal clutter. The designed FMCW radar can acquire altitude information from the ground clutter with $\sigma_0=-23dB$ at the height of 160m. The fabricated W-band FMCW radar transmits 11 dBm power and the dynamic range of the receiver is from -106dBm to -30dBm. The performances of the fabricated sensors were tested out in the fields and detected a car target of 200m apart on the grass.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.5
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• pp.58-66
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• 2002

We present a planting plan of the buffer-forest belts created at the boundary area of the waste landfill site which is located in the coastal area of Kyubg-Gi province. In order to form a proper section of ground soil excavated from the sea and a forest which shows a distinction of the vegetation stratification, the planting plan with trees, sub-trees, shrubs, and seedlings (produced at a sprout cultivation place) is devised with an adjustment of planting density. 1. The preparation of mounding is required for planting at a waste landfill site. We first estimate an economical and efficient banking height together with the quantity of soil, and prepare a planting ground with excavated ground soil for the consideration of soil recycling. On the planting ground a banking with a height of 1.5-2m is produced by self-supported soil, playing a role in a salt blocking and an irritation layer of planting. Finally, an additional banking with a height of 2m is produced by qualified vegetation soil, forming a vegetation section with a total height of 6m. 2. Since the planning site is located in the border, the planting area is composed of two regions : one is an inclined face (slope 1 : 3) toward the inside of the landfill site and the other is an inclined face (slope 1 : 4) toward the inland. The buffer planting in the former (latter) region consists of wind break forest (mixed-landscape forest) within a width of less than 35m. 3. Based on the data obtained from the literatures and the investigation of local plants, we choose the 21 plant species (such as Pinus thunbergii, Pinus densiflora, Sorbus alnifolia, Albizzia julibrissin and etc.) and the additinal 7 species which are grown at a sprout cultivation palce of the SUDOKWON landfill site (Rosa rugosa, Quercus acutissima, Prunus armeniaca var. ansu., and etc.). Sub-trees with a height of above 2.5m and seedlings are planted with an interval of $1.5{\times}1.5m$ ($0.45roots/m^2$) and $0.5{\times}0.5m$ ($4roots/m^2$), respectively. Here, both trees exhibit communities planting with more than three rows. Shrubs are planted with $9-16roots/m^2$, depending on their size. Since this case study provides a reference of the planting beds as well as a planting plan at the SUDOKWON landfill site, it is not sufficient for the present plan to be utilized for the formation of buffer-forest belts which are used for the analysis of environmental factor and the reduction of environmental pollutants in the sea waste landfill site. Thus, further studies with the ecological basis are demanded for the environment planting restoration in the sea waste landfill site.

• Journal of the Earthquake Engineering Society of Korea
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• v.25 no.5
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• pp.223-232
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• 2021

The spatial variation characteristics of seismic motions at the nuclear power plant's site and structures were analyzed using earthquake records obtained at the Fukushima nuclear power plant during the Great East Japan Earthquake. The ground responses amplified as they approached the soil surface from the lower rock surface, and the amplification occurred intensively at about 50 m near the ground. Due to the soil layer's nonlinear characteristics caused by the strong seismic motion, the ground's natural frequency derived from the response spectrum ratio appeared to be smaller than that calculated from the shear wave velocity profile. The spatial variation of the peak ground acceleration at the ground surface of the power plant site showed a significant difference of about 0.6 g at the maximum. As a result of comparing the response spectrums at the basement of the structure with the design response spectrum, there was a large variability by each power plant unit. The difference was more significant in the Fukushima Daiichi site record, which showed larger peak ground acceleration at the surface. The earthquake motions input to the basement of the structure amplified according to the structure's height. The natural frequency obtained from the recorded results was lower than that indicated in the previous research. Also, the floor response spectrum change according to the location at the same height was investigated. The vertical response on the foundation surface showed a significant difference in spectral acceleration depending on the location. The amplified response in the structure showed a different variability depending on the type of structure and the target frequency.

• Journal of Advanced Navigation Technology
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• v.13 no.6
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• pp.820-830
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• 2009

This paper illustrates how simulation modeling can be reduced of ground turbulence by the constructions in the vicinity of airport runway and reports on a cause of ground turbulence using two-dimensional CFD analysis. Interesting result is that the shape in cross-section show the higher ground turbulence than the height of the building. The predicted results confirmed reduction of wind-effect by doing that set up the building with a fence, terraced shape or gap and it can generate turbulence in embryo at this stage. We knows that cross-wind effect in the vicinity of airport runway is highly dependent on the shape of the buildings.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.7
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• pp.12-17
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• 2006

Longitudinal static stability and steady aerodynamic characteristics of wings flying over nonplanar ground surfaces (rail and channel) are investigated using the boundary-element method. For a channel with it's fence higher than the wing height, the lift and the nose-down pitching moment increase as the gap between the wingtip and the fence decreases. For a rail with it's width wider than the wing span, the lift and the nose-down pitching moment increase as the rail height decreases. Longitudinal static stability of a single wing flying over nonplanar surfaces is worse than the case of the flat ground. In case of tandem wings, longitudinal static stability of the wings flying over the channel is better than the case of the flat ground. It is believed that the present results can be applied to the conceptual design of high-speed ground transporters.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.3
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• pp.295-303
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• 2012

Clarify wind energy productivity depends on three factors: the wind probability density function(PDF), the turbine's power curve, and the air density. The wind PDF gives the probability that a variable will take on the wind speed value. Wind shear refers to the change in wind speed with height above ground. The wind speed tends to increase with the height above ground. also, Wind PDF refers to the change with height above ground. Wind analysts typically use the Weibull distribution to characterize the breadth of the distribution of wind speeds. The Weibull distribution has the two-parameter: the scale factor c and the shape factor k. We can use a linear least squares algorithm(or Ln-least method) and moment method to fit a Weibull distribution to measured wind speed data which data was located same site and different height. In this study, find that the scale factor is related to the average wind speed than the shape factor. and also different types of terrain are characterized by different the scale factor slop with height above ground. The gross turbine power output (before accounting for losses) was caculated the power curve whose corresponding air density is closest to the air density. and air desity was choose two way. one is the pressure of the International Standard Atmosphere up to an elevation, the other is the measured air pressure and temperature to calculate the air density. and then each power output was compared.