• Korean Journal of Environmental Agriculture
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• v.33 no.1
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• pp.44-51
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• 2014

BACKGROUND: Water quality of rural areas are susceptible to agricultural nutrient input and supply such as chemical fertilizer and livestock manure. This study was conducted to evaluate the usefulness of nutrient (N and P) indices in understanding spatial variations of water quality across Chonnam province which is a typical agricultural region in Korea. METHODS AND RESULTS: The nutrient indices including chemical fertilizer supply, livestock manure production, and nutrient balance were correlated with water quality data (T-N, T-P, BOD, and COD) for the twenty-two districts of the province. Concentration of T-N were positively correlated with chemical fertilizer supply, livestock manure N production, and nutrient balance (P<0.05 or P<0.01). Meanwhile, T-P concentration was not correlated with these nutrient indices; however, there was a tendency that T-P concentration increases with livestock manure P production (P=0.06) and with nutrient balance (P=0.09). These results suggest that T-N concentration is susceptible to both chemical fertilizer and livestock manure; whereas T-P is likely to be affected by livestock manure rather than chemical fertilizer. The concentrations of BOD and COD were also positively (P<0.05 or P<0.01) correlated with livestock manure production. CONCLUSION: This study shows the usefulness of nutrient indices in understanding spatial variations of water quality and suggests that livestock manure rather than chemical fertilizer can be a more critical water pollution source and thus highlights the need for more attention to livestock manure treatments for rural water quality management.

• Journal of The Korean Association of Information Education
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• v.18 no.1
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• pp.13-23
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• 2014

For this paper, we developed a game-addiction therapy program for students with gaming addiction based on multiple intelligences (MI) and verified its effects. The participants were 54 elementary students selected through a game addiction test in Incheon City, Korea. We tested the students' MI to facilitate program development. the students with gaming addiction showed strengths in the Bodily-kinesthetic, Naturalist, and Spatial intelligences whilst showing weaknesses in the Logical-mathematical, Intrapersonal, and Interpersonal intelligences as opposed to normal students who had opposite results. We arranged the program around various gaming and playing activities to engage their stronger intelligences; we added activities to address their weakness (i.e., Logical-mathematical, Intrapersonal, and Interpersonal intelligences). This study has shown that this program lowered the game immersion level of the students and was helpful in turning their attention to other activities. There were significant differences between pretest and posttest game addiction scores (p<0.001). Their weekly gaming time and computer usage decreased rapidly. Satisfaction with the game addiction therapy program based on MI was very high.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.184-184
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• 2012

Recently, InGaN/GaN multi-quantum well grown on GaN pyramid structures have attracted much attention due to their hybrid characteristics of quantum well, quantum wire, and quantum dot. This gives us broad band emission which will be useful for phosphor-free white light emitting diode. On the other hand, by using quantum dot emission on top of the pyramid, site selective single photon source could be realized. However, these structures still have several limitations for the single photon source. For instance, the quantum efficiency of quantum dot emission should be improved further. As detection systems have limited numerical aperture, collection efficiency is also important issue. It has been known that micro-cavities can be utilized to modify the radiative decay rate and to control the radiation pattern of quantum dot. Researchers have also been interested in nano-cavities using localized surface plasmon. Although the plasmonic cavities have small quality factor due to high loss of metal, it could have small mode volume because plasmonic wavelength is much smaller than the wavelength in the dielectric cavities. In this work, we used localized surface plasmon to improve efficiency of InGaN qunatum dot as a single photon emitter. We could easily get the localized surface plasmon mode after deposit the metal thin film because lnGaN/GaN multi quantum well has the pyramidal geometry. With numerical simulation (i.e., Finite Difference Time Domain method), we observed highly enhanced decay rate and modified radiation pattern. To confirm these localized surface plasmon effect experimentally, we deposited metal thin films on InGaN/GaN pyramid structures using e-beam deposition. Then, photoluminescence and time-resolved photoluminescence were carried out to measure the improvement of radiative decay rate (Purcell factor). By carrying out cathodoluminescence (CL) experiments, spatial-resolved CL images could also be obtained. As we mentioned before, collection efficiency is also important issue to make an efficient single photon emitter. To confirm the radiation pattern of quantum dot, Fourier optics system was used to capture the angular property of emission. We believe that highly focused localized surface plasmon around site-selective InGaN quantum dot could be a feasible single photon emitter.

• Journal of Science Education
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• v.33 no.2
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• pp.193-206
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• 2009

The purpose of this study was to examine the effect of the consistent presentation of illustrations about the aligning direction of the Axis on the middle school students' acquisition and retention of astronomical concepts. This study was taken using the nonequivalent control-group pretest-posttest design on 116 7th middle school subjects. The same teaching and learning activities were given to both the experimental (n=59) and control groups (n=57) through three lessons. The experimental group was given a consistent presentation of the illustrations about the aligning direction of the Axis, while the control group was given an inconsistent presentation of the same illustrations about aligning direction. Two days after the three lessons, the 1st posttest was administered to compare the statistical difference of mean of both groups, using ANCOVA test. The result of ANCOVA test implicated that the consistent presentation of the illustrations about the aligning direction of the Axis had a positive influence on the experimental group's acquisition of the concepts. The 2nd posttest result for retention effect was given two month later by one-paired t-Test in each group and showed that the method had a positive effect on the experimental group, compared with control group. The results of this study implicated that paying careful attention to using the consistent illustration is highly beneficial for students' meaningful learning on astronomical concepts.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.23-23
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• 2009

GaN-based nitride semiconductors have attracted considerable attention in high-brightness light-emitting-diodes (LEDs) and laser diodes (LDs) covering from green to ultraviolet spectral range. LED and LD heterostructures are usually grown on (0001)-$Al_2O_3$. The large lattice mismatch between $Al_2O_3$ substrates and the GaN layers leads to a high density of defects(dislocations and stacking faults). Moreover, Ga and N atoms are arranged along the polar [0001] crystallographic direction, which leads to spontaneous polarization. In addition, in the InGaN/GaN MQWs heterostructures, stress applied along the same axis can also give rise to piezoelectric polarization. The total polarization, which is the sum of spontaneous and piezoelectric polarizations, is aligned along the [0001] direction of the wurtzite heterostructures. The change in the total polarization across the heterolayers results in high interface charge densities and spatial separation of the electron and hole wave functions, redshifting the photoluminescence peak and decreasing the peak intensity. The effect of polarization charges in the GaN-based heterostructures can be eliminated by growing along the non-polar [$11\bar{2}0$] (a-axis) or [$1\bar{1}00$] (m-axis) orientation instead of thecommonly used polar [0001] (c-axis). For non-polar GaN growth on non-polar substrates, the GaN films have high density of planar defects (basal stacking fault BSFs, prismatic stacking fault PSFs), because the SFs are formed on the basal plane (c-plane) due to their low formation energy. A significant reduction in defect density was recently achieved by applying blocking layer such as SiN, AlN, and AlGaN in non-polar GaN. In this work, we were performed systematic studies of the defects in the nonpolar GaN by conventional and high-resolution transmission electron microscopy.

• Journal of Broadcast Engineering
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• v.22 no.6
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• pp.785-799
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• 2017

One of the most widely used image media in recent years, omni-directional panorama images are attracting much attention. Since this image is ultra-high value-added, the intellectual property of this image must be protected. In this paper, we propose a blind digital watermarking method for this image. In this paper, we assume that the owner of each original image may be different, insert different watermark data into each original image, and extract the watermark from the projected image, which is a form of service of omni- directional panorama image. Therefore, the main target attack in this paper is the image distortion which occurs in the process of the omni- directional panorama image. In this method, SIFT feature points of non-stitched areas are used, and watermark data is inserted into data around each feature point. We propose two methods of using two-dimensional DWT coefficients and spatial domain data as data for inserting watermark. Both methods insert watermark data by QIM method. Through experiments, these two methods show robustness against the distortion generated in the panorama image generation process, and additionally show sufficient robustness against JPEG compression attack.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.1069-1074
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• 2009

Public displays are evolving from a one-way display to an interactive medium which contains dynamic transition of various media. This study focuses on the interaction between human and digital technology-based art on public display from a HCI point of view, while several viewpoints exist on interactive public displays. We present a new interaction model which suggests different interactions depending on the viewer's distance and direction so that public display could offer rich media experiences. We have also and built an installation art to examine the efficacy of our interaction model. As such, we introduced two methodologies from HCI to derive our final interaction model. First of all, we analyze previous distance-dependent interaction models for public display in terms of context analytic approach, and propose an effective model for human-digital art interaction. Second, we introduce the concept of aura in HCI as user analytic approach to redefine interaction depending on the viewer's direction of attention. Thus, this study aims to suggest a new interaction model based on the previous two analyses to improve interaction between human and digital technology-based art on public display.

• Science of Emotion and Sensibility
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• v.21 no.2
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• pp.3-14
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• 2018

For satisfying consumer needs, commercial facilities require a variety of sale-related space expressions and eye-catching product arrangements; space composition can also be a direct marketing strategy. The human eye is the sensory organ that acquires the largest amount of information, and an analysis of visual information helps in understanding visual relations between . However, the existing studies are mostly focused on analysis of still frames in experimental images, and there is a lack of studies analyzing gaze information based on mobile images of commercial spaces. Therefore, this study analyzed emotional responses through gaze information of space users in reality using a video of a movement route through a commercial facility. The analysis targeted straight sections of the moving route; based on the data acquired, sectional characteristics of five gaze intensity ranges were examined. As a result, section A, the starting point of the route, had a low gaze intensity, while section B had the highest gaze intensity. This indicates that, starting in section B, the subjects explored the space in a stable way and needed time to adapt to the experimental video. In relation to space characteristics of the gaze-concentrated area, display formats of the right stores in 4 of 6 sections received greater attention. The gaze of consumers was mostly focused on props, and big gaze information was revealed in showcase display formats of the stores. In conclusion, this analysis method can provide highly useful direct design data about merchandise display and merchandise component arrangement based on consumer visual preference.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.3
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• pp.293-301
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• 2005

In case of the roads that pass the mountain area, the cut sections or the tunnels are constructed. And In winter season it appears sunshine few in the specific segment, the shade is continued last and the freezing sections occur. So, the attention is necessary in traffic safety. This study was to evaluate the influence of sunshine and surface freezing sections expected in route plans of roads using GIS and makes alternative ideas in road stability security. After selecting 29 km sections of Donghae highway and creating a 3 dimensional terrain surface through the digital conversion of design plan data, it reflects the road alignment data of the same coordinates and a 3 dimensional road modeling is created. It set shadow time of road surface for the solar trace in the winter solstice in 20 minute interval. Shade areas are displayed and inputed in polygon data by manual vertorizing. Graphic and attribute data of this shade section is constructed in geodatabase of ArcCatalog. And it extracted the freezing section using intersect fuction of the GIS spatial analysis. By analyzing the winter meteorological data of temperature, rainfall, snowfall, humidity, and etc. and grasping dangerous freezing section of the road surface effectively, it will be able to make alternative ideas of the preliminary stability evaluation reflected in basic design.

• The Journal of the Korea Contents Association
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• v.14 no.6
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• pp.247-254
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• 2014

For the purpose of early diagnosis of the breast cancer, the attention on the screening mammography has been increasing-with supply of digital mammography day by day. Image quality is decided by target materials and filter combinations. Optimized selection by a glandular density and a thickness is needed, because these combinations change x-ray spectrum and effect to image quality. The purpose of this study is to find out optimized target and filter combinations through the evaluation of quantitative image quality and to suggest means which minimize patient dose through MCNPX. In results, spatial frequency resolution evaluation which is quantitative image quality evaluation method, MTF, NPS, DQE shows that we have to select Mo/Mo combinations or Mo/Rh combinations when compressed breast is thin. but in case of that when compressed breast is thick, we have to select Rh/Rh combinations or W /Rh combinations. In a comprehensive evaluation, W!Rh combinations which are not used in thin breasts in practice was superior to all image quality evaluation. This result is somewhat different-with clinical examination results. Secondary end point was organ dose evaluation, radiation dose of opposite breast was approximately 47 ~73% effectiveness when selecting standard breast. In conculsion, the most important point is that we have to select the optimal combinations-with considering dose evaluation and various thickness.