• Journal of Forest and Environmental Science
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• v.33 no.4
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• pp.305-314
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• 2017

This study aimed to predict changes in forest area using a probability density function, in order to promote effective forest management in the area north of the civilian control line (known as the Minbuk area) in Korea. Time series analysis (2010 and 2016) of forest area using land cover maps and accessibility expressed by distance covariates (distance from buildings, roads, and civilian control line) was applied to a probability density function. In order to estimate the probability density function, mean and variance were calculated using three methods: area weight (AW), area rate weight (ARW), and sample area change rate weight (SRW). Forest area increases in regions with lower accessibility (i.e., greater distance) from buildings and roads, but no relationship with accessibility from the civilian control line was found. Estimation of forest area change using different distance covariates shows that SRW using distance from buildings provides the most accurate estimation, with around 0.98-fold difference from actual forest area change, and performs well in a Chi-Square test. Furthermore, estimation of forest area until 2028 using SRW and distance from buildings most closely replicates patterns of actual forest area changes, suggesting that estimation of future change could be possible using this method. The method allows investigation of the current status of land cover in the Minbuk area, as well as predictions of future changes in forest area that could be utilized in forest management planning and policymaking in the northern area.

• Journal of Digital Convergence
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• v.17 no.11
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• pp.97-104
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• 2019

Consumers possess their own psychological distance towards products. Based on the construal-level theory, this study aims to analyze which type of advertising appeal is more effective according to psychological distance. Also this study conducts neurophysiology experiment through eye-tracker. By using eye-tracking methods, participants' responses to products was measured and analyzed accordingly. Results revealed that consumers prefer rational appeals when the psychological distance is perceived near, while emotional appeals are preferred when the psychological distance is perceived far. In addition, eye movements measured in Visit Count(VC), Fixation Count(FC), and Total Fixation Duration(TFD) showed significant difference when participants are viewing preferred and non-preferred appeals.

• Journal of IKEEE
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• v.22 no.4
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• pp.922-932
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• 2018

Radial distance sensors are widely used for surveying and autonomous navigation. It is necessary to train the operation principle of these sensors and how to apply them. Although commercialization of radial distance sensor continues to be cost-effective through lower performance, but it is still expensive for educational purposes. In this paper, we propose a distance sensor module with object tracking using radial array of low cost phototransistor which can be used for educational robot. The proposed method is able to detect the position of a fast moving object immediately by arranging the phototransistor in the range of 180 degrees and improve the sensing angle range and track the object by the sensor rotation using the servo motor. The scan speed of the proposed sensor is 50~200 times faster than the commercial distance sensor, thus it can be applied to a high performance educational mobile robot with 1ms control loop.

• Journal of Animal Environmental Science
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• v.14 no.3
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• pp.159-166
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• 2008

This research was carried out to test and analyze capacity of the long distance sprayer fan in large livestock farmhouses. Long distance sprayer was manufactured to be able to spray a lot of water, which was a solvent for agricultural chemicals and black dye with the maximum spraying distance of 140 m and the effective spraying distance of 100 m. The spraying quantity and the distance were measured the intensity values of images within A4 papers, which absorbed the agricultural chemicals by spraying by binary image processing. These A4 papers were fixed upon the height of 1 m from soil ground at regular 10 m interval. After the A4 papers were collected and analyzed the intensity values of gray level. Gray level was ranged from 0 to 255, where 0 was black and 255 was white. A4 paper was fallen down from the stick at 10 m distance, because there were too large amount of sprayed water with black dye. Also, the paper showed low gray level at distance 30 m because of dropping lots of black water. The intensity value of gray level was showed almost less than 200 on the A4 papers between the distance 20 m and 100 m, which meant equality of spraying quantity. Additionally, it was possible to spay agricultural chemicals of until 180 m. Throughout this research, long distance sprayer could apply for preventing hoof-and-mouth disease in large livestock farmhouses.

• Journal of radiological science and technology
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• v.44 no.1
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• pp.39-46
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• 2021

This study confirmed the usefulness of the copper filter according to the mode change by comparing and analyzing the energy change according to the application of the copper filter and the change in effective dose and image quality according to the distance to the subject in the DR(Digital Radiography) system. The average energy increased when the copper filter was applied and the reduction rate by 50% of mAs was increased as the thickness of the copper filter increased according to the application of the 10 kVp rule in AEC mode. The effective dose decreased as the thickness increased when the copper filter was applied in AEC(Automatic Exposure Control) mode and manual mode according to the application of the 10 kVp rule, and the decrease rate decreased with increasing 10 kVp increments. As a result of analyzing the dicom images for AEC mode and manual mode with Image J. the PSNR(Peak Signal to Noise Ratio) values were approximate values of less than 30 dB for each mode and for each copper filter thickness. When the copper filter was applied, the average energy increased, so when the 10 kVp rule was applied, the mAs for each mode could be reduced, and the effective dose could also be reduced. However, as the distance and tube voltage increased, the reduction rate of mAs decreased, and the quality of the image was found to decrease when the copper filter was applied, but there was no difference in quality of the image when the copper filter thickness increased.

• Journal of the military operations research society of Korea
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• v.16 no.1
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• pp.94-112
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• 1990

The basic mathematical tools are developed to determine the optimum emplacement of limited numbers of scatterable mines on the infantry battlefield. A deterministic model is developed for heterogeneous infantry battalion level battle using APL version 7.0. The Helmbold-type combat equation is applied to claculate comparative casulties, and range dependency is also considered to establish the correlation between attrition rate coefficients and the distance of opposing forces, Based on this deterministic model the effective range for employment of scatterable mines is determined. Because mines are primarily effective when employed in conjunction with direct fire weapons, it is inferred that minefield are best employed when used within the maximum effective range of infantry weapons systems such as the M16Al rifle. The model developed verifies this fact.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.277-280
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• 2000

In this paper, we designed a turbo decoder using VHDL. To maximize effective free distance of the turbo code, we implemented pseudo random interleaver. A MAP(Maximum a posteriori) decoder is used as a primimary decoder. We avoided multiplication by using lookup tables(ROM). We expect that this small-sized turbo decoder is suitable for mobile communication. We simulated turbo decoder with Altera MAX+PLUS II.

• Explosives and Blasting
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• v.28 no.2
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• pp.50-58
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• 2010

This study explores the slot-drilling method that has not yet enough been studied in Korea and intends to provide a theoretical framework for putting the method into practice in a construction site. The possible reduction of ground vibration by implementing slot-drilling methods is addressed. Two main subjects dealt with include the variation of vibration velocity that is based on the distance between the slot-drilling and the epicenter of blasting and the analysis of appropriate effective dimension of slot-drilling width and height to control blasting vibration. This study shows that effect of vibration reduction decreases when distance of the slot-drilling and the epicenter of blasting is getting larger and also reveals that there is a correlation between the slot size and the vibration velocity at any point.

• Structural Engineering and Mechanics
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• v.74 no.6
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• pp.737-745
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• 2020

Nowadays, composite plates are widely used as high-strength structures to fabricate a dynamic loading-resistant armours. In this study, the shock load is applied by an explosion of spherical TNT charge at a specified distance from the circular composite plate. The composite plate contains a two-layer ceramic-metal armour and a poly-methyl methacrylate (PMMA) target layer. The dynamic behavior of the composite armour has been investigated by measuring the transferred effective stress and maximum deflection into the target layer. For this purpose, the simulation of the blast loading upon the composite structure was performed by using the load-blast enhanced (LBE) procedure in Ls-Dyna software. The effect of main process parameters such as the thickness of layers, and scaled distance has been examined on the specific stiffness of the structure using response surface method. After validating the results by comparing with the experimental results, the optimal values for these parameters along with the regression equations for transferred effective stress and displacement to the target have been obtained. Finally, the optimal values of input parameters have been specified to achieve minimum transferred stress and displacement, simultaneously with reducing the weight of the structure.

• Computers and Concrete
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• v.5 no.4
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• pp.375-388
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• 2008

Crack opening governs many transfer properties that play a pivotal role in durability analyses. Instead of trying to combine continuum and discrete models in computational analyses, it would be attractive to derive from the continuum approach an estimate of crack opening, without considering the explicit description of a discontinuous displacement field in the computational model. This is the prime objective of this contribution. The derivation is based on the comparison between two continuous variables: the distribution if the effective non local strain that controls damage and an analytical distribution of the effective non local variable that derives from a strong discontinuity analysis. Close to complete failure, these distributions should be very close to each other. Their comparison provides two quantities: the displacement jump across the crack [U] and the distance between the two profiles. This distance is an error indicator defining how close the damage distribution is from that corresponding to a crack surrounded by a fracture process zone. It may subsequently serve in continuous/discrete models in order to define the threshold below which the continuum approach is close enough to the discrete one in order to switch descriptions. The estimation of the crack opening is illustrated on a one-dimensional example and the error between the profiles issued from discontinuous and FE analyses is found to be of a few percents close to complete failure.