• Journal of the Korea Society of Computer and Information
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• v.19 no.8
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• pp.35-44
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• 2014

This paper proposes a 3D pointing interface that is designed for the efficient application of a hand mouse. The proposed method uses depth images to secure high-quality results even in response to changes in lighting and environmental conditions and uses the normal vector of the palm of the hand to perform 3D pointing. First, the hand region is detected and tracked using the existing conventional method; based on the information thus obtained, the region of the palm is predicted and the region of interest is obtained. Once the region of interest has been identified, this region is approximated by the plane equation and the normal vector is extracted. Next, to ensure stable control, interpolation is performed using the extracted normal vector and the intersection point is detected. For stability and efficiency, the dynamic weight using the sigmoid function is applied to the above detected intersection point, and finally, this is converted into the 2D coordinate system. This paper explains the methods of detecting the region of interest and the direction vector and proposes a method of interpolating and applying the dynamic weight in order to stabilize control. Lastly, qualitative and quantitative analyses are performed on the proposed 3D pointing method to verify its ability to deliver stable control.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.4
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• pp.389-398
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• 2002

As the necessity of land information has increased according to development of computer and Information-communication, people have been interested in the satellite measurement system that can update Cadastral and Geographical information rapidly and exactly. Most Cadastral base points which had limitation of measurement technology in the 1910s were less accurate and were destroyed through the Korean War. They also many problems in the process of reinstallation. So, they require the quick and correct method of measurement in re-equipment of a base point and a parcel based survey and so on. This study intends to present the GPS survey direction by understanding and analysing all sorts of problems rising in case of applying the GPS to cadastral area in order to increase the efficiency of the GPS measurement, and also develop the GPS kinematic survey program to apply to the efficiency of a kinematic survey. As a result of research, I could confirm the accuracy of Cadastral base points in Kwangju area by using Korea GPS array and a base point, and could get the result similar to existent cadastral survey result with the coordinate conversion program of Cadastral technology research institute. We however have to pay our attention to the transformation of the plane coordinates because the difference between tens of cm and the existing result can outbreak according to the Gauss conformal double projection method. And, I could figure out the practicality of the developed GPS kinematic survey program, compared with common use program. I expect that it can be applied to the digital cadastral survey and the cadastral map renewal as well.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12C
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• pp.1029-1038
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• 2008

In this paper, we propose a method for an arbitrary-view image generation in multi-view video and methods for pre- and post-processing to compensate unattended regions in the generated image. To generate an arbitrary-view image, camera geometry is used. Three dimensional coordinates of image pixels can be obtained by using depth information of multi-view video and parameter information of multi-view cameras, and by replacing three dimensional coordinates on a two dimensional image plane of other view, arbitrary-view image can be reconstructed. However, the generated arbitrary-view image contains many unattended regions. In this paper, we also proposed a method for compensating these regions considering temporal redundancy and spatial direction of an image and an error of acquired multi-view image and depth information. Test results show that we could obtain a reliably synthesized view-image with objective measurement of PSNR more than 30dB and subjective estimation of DSCQS(double stimulus continuous quality scale method) more than 3.5 point.

• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.3155-3167
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• 2018

The purpose of this study was to investigate factor of principals' trust in teachers which principals of secondary school recognized and to explore their needs on building trust in teachers. For this purpose, this study used survey question of which investigated conception of principals' trust in teachers and performed with 296 secondary school principals. First, gap of two statuses was proven by t-test. Second, the order of priority was presented by Borich model. Third, the result of the locus for focus model was presented in the form of coordinate plane. Lastly, top priority and the second priority were determined. The result of this study was as following. 'Class management, instruction, and caring for students' category is highest in needs of secondary school principals on trust in teachers. Next, second priority category is 'partnership with parents'. It means secondary school principals recognize that students and parents are most important on education and their trust in teachers. Based on the review, finding and implications are discussed.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.30 no.2
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• pp.71-90
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• 2021

The virtual patient dataset is a collection of diagnostic data from various sources acquired from a single patient into a coordinate system of three-dimensional visualization. Virtual patient dataset makes it possible to establish a treatment plan, simulate various treatment procedures, and create a treatment planning delivery device. Clinicians can design and simulate a patient's smile on the virtual patient dataset and select the optimal result from the diagnostic process. The selected treatment plan can be delivered identically to the patient using manufacturing techniques such as 3D printing, milling, and injection molding. The delivery of this treatment plan can be linked to the final prosthesis through mockup confirmation through provisional restoration fabrication and delivery in the patient's mouth. In this way, if the diagnostic data superimposition and processing accuracy during the manufacturing process are guaranteed, 3D digital smile design simulated in 3D visualization can be accurately delivered to the real patient. As a clinical application method of the virtual patient dataset, we suggest a decision-making method that can exclude occlusal adjustment treatment from the treatment plan through the digital occlusal pressure analysis. A comparative analysis of whole-body scans before and after temporomandibular joint treatment was suggested for adolescent idiopathic scoliosis patients with temporomandibular joint disease. Occlusal plane and smile aesthetic analysis based on the virtual patient dataset was presented when treating patients with complete dentures.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.6
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• pp.267-274
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• 2023

In this paper, a method for estimating the illuminant chromaticity of a scene for an input image is proposed. The illuminant chromaticity is estimated using the illuminant reference region. The conventional method uses a certain number of reference lighting information. By comparing the chromaticity distribution of pixels from the input image with the chromaticity set prepared in advance for the reference illuminant, the reference illuminant with the largest overlapping area is regarded as the scene illuminant for the corresponding input image. In the process of calculating the overlapping area, the weights for each reference light were applied in the form of a Gaussian distribution, but a clear standard for the variance value could not be presented. The proposed method extracts an independent reference chromaticity region from a given reference illuminant, calculates the characteristic values in the r-g chromaticity plane of the RGB color coordinate system for all pixels of the input image, and then calculates the independent chromaticity region and features from the input image. The similarity is evaluated and the illuminant with the highest similarity was estimated as the illuminant chromaticity component of the image. The performance of the proposed method was evaluated using the database image and showed an average of about 60% improvement compared to the conventional basic method and showed an improvement performance of around 53% compared to the conventional Gaussian weight of 0.1.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.2935-2940
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• 2023

A polystyrene phantom was developed following the guidance of the International Atomic Energy Association (IAEA) for gamma knife (GK) quality assurance. Its performance was assessed by measuring the absorbed dose rate to water and dose distributions. The phantom was made of polystyrene, which has an electron density (1.0156) similar to that of water. The phantom included one outer phantom and four inner phantoms. Two inner phantoms held PTW T31010 and Exradin A16 ion chambers. One inner phantom held a film in the XY plane of the Leksell coordinate system, and another inner phantom held a film in the YZ or ZX planes. The absorbed dose rate to water and beam profiles of the machine-specific reference (msr) field, namely, the 16 mm collimator field of a GK Perfexion^TM or Icon^TM, were measured at seven GK sites. The measured results were compared to those of an IAEA-recommended solid water (SW) phantom. The radius of the polystyrene phantom was determined to be 7.88 cm by converting the electron density of the plastic, considering a water depth of 8 g/cm². The absorbed dose rates to water measured in both phantoms differed from the treatment planning program by less than 1.1%. Before msr correction, the PTW T31010 dose rates (PTW Freiberg GmbH, New York, NY, USA) in the polystyrene phantom were 0.70 (0.29)% higher on average than those in the SW phantom. The Exradin A16 (Standard Imaging, Middleton, WI, USA) dose rates were 0.76 (0.32)% higher in the polystyrene phantom. After msr correction factors were applied, there were no statistically significant differences in the A16 dose rates measured in the two phantoms; however, the T31010 dose rates were 0.72 (0.29)% higher in the polystyrene phantom. When the full widths at half maximum and penumbras of the msr field were compared, no significant differences between the two phantoms were observed, except for the penumbra in the Y-axis. However, the difference in the penumbra was smaller than variations among different sites. A polystyrene phantom developed for gamma knife dosimetry showed dosimetric performance comparable to that of a commercial SW phantom. In addition to its cost effectiveness, the polystyrene phantom removes air space around the detector. Additional simulations of the msr correction factors of the polystyrene phantom should be performed.

• Journal of the Korean Institute of Landscape Architecture
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• v.52 no.1
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• pp.1-16
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• 2024

Alvin Toffler mentioned that it is important for future society to keep pace with synchronization and that time deviations can hinder social development. As we experience the new normal era of untact, we have experienced an increase in non-face-to-face contact and accelerated digital transformation. Amid these rapid changes, we can maintain the need for synchronization or change in space. Therefore, we would like to study what kind of settlements people create and choose. We looked at the metaverse as an object that could indirectly find out about this, and used the content called "Animal Crossing" to collect data related to the spatial form of the metaverse. Sampling utilized a judgment sampling method during non-probability sampling to alleviate differences due to the progress of the game. The collected data was classified according to floor plan and location type and briefly organized through descriptive statistics. After matching each facility by use, data was constructed by setting coordinates for each cluster and listing them. This data was interpreted graphically on the coordinate plane for each cluster, and Euclidean analysis was performed to analyze the relationships between clusters and residential choice using a Euclidean matrix. As a result of the analysis, it could be interpreted that efficiency was pursued by arranging similar functions in close proximity. Nevertheless, when choosing a residence, it was interpreted that the intention was to create a community through arrangement adjacent to residents rather than efficiency or convenience. Due to the differences between the metaverse and the real world, it is expected that there will be limitations in equating it with reality. However, through the space expressed in the virtual world by people who are far away from the constraints of reality, we can indirectly know the wishes that we have not been able to express due to our lack of awareness.

• The Journal of the Korean life insurance medical association
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• v.2 no.1
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• pp.195-217
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• 1985

A statistical analysis on the ratio of weight-for-height in insurance medicine was carried out in a total of 12,690 insured persons who were medically examined at the Honam medical department, Dong Bang life insurance company, ltd. from June, 1979 to February, 1984. The results were as follows: 1. The mean value of the ratio of weight-for-height(W/H ratio) was $102.3{\pm}11.3%$ in all males, and $105.2{\pm}103.6%$ in all females. The difference of the values between males and females showed statistical significance(P<0.001). The mean value of W/H ratio in all the insureds was $103.8{\pm}12.9%$. In each age group, the mean value of female was higher than that of male without exception(P<0.001). The mean value of both sexes in each age group showed gradual increase with age except for the age group over 50(P<0.001). 2. The incidences of the average weighted, overweighted and underweighted lives were respectively 91.6% in all males, 84.2% in all females(P<0.001); 7.9% in all males, 15.4% in all females(P<0.001); 0.5% in all males, 0.4% in all females(P>0.05). The incidences of average weighted, overweighted and underweighted lives in all the insureds were respectively 87.6%, 12.0% and 0.5%. The incidence of the average weighted lives in male in each age group was always higher than that in female with the exception of the age group below 19(P<0.001), whereas the incidence of the overweighted lives in male in each age group was always lower than that in female(P<0.05 in the age group below 19, P<0.001 in the other age groups). The incidence of average weighted lives of both sexes in each age group showed gradual decrease with age from the second to fifth decade(P<0.001), whereas the incidence of the overweighted lives of both sexes in each age group showed gradual increase with age from the second to fifth decade(P<0.001). 3. The relative frequency distribution polygons of W/H ratio of both sexes drawn in a pair on one coordinate plane revealed lying in juxtaposition each other horizontally and showed the shifting of female's polygon to male's one toward the direction of greater value of W/H ratio at a short distance which increased gradually with age. 4. Correlations between both sexes and among age groups relating to W/H ratios of the insureds seem to be a physiological phenomenon of body build and should be considered on the rating of the build. Author prepared a rating table of build based on the correlations above menthioned. Some gradients by sex and age in the rating table of build are organized; in female group, the ratings of 0, 30-50, 50-100 and 100-D are to calculate by the build with W/H ratio of 80-125%, $126{\sim}145%,\;146{\sim}165%$ and over 166% respectively in the age group of 29 or under, by the build with W/H ratio of $80{\sim}130%,\;131{\sim}150%,\;151{\sim}170%$ and over 171% respectively in the age group of $30{\sim}59$, and by the build with W/H ratio of $80{\sim}135%,\;136{\sim}155%,\;156{\sim}175%$ and over 176% respectively in the age group of 60 or over. In male group, the ratings of 0, $30{\sim}50$, 50-100, and 100-D are to calculate by the build with W/H ratio of $80{\sim}120%,\;121{\sim}140%,\;141{\sim}160%$ and over 161% respectively in all ages. Of under weighted lives, in both sexes, the ratings of 30-50 and 50-D are to calculate by the build with W/H ratio of $76{\sim}79%$ and under 75% respectively. The results of the ratings according to a rating table by author were as follows: The incidence of the ratings of 0, 30-50, 50-100 and 100-D showed no difference between male and female. The incidence of the ratings of 0(indicating the average weighted lives) showed gradual decrease with age and the incidence of the ratings of 30-50 and 50-100(indicating the overweighted lives) showed gradual increase with age. These results are thought to be considerably reasonable because the incidence of the builds in each age group is supposed to have no difference by sex and the incidence of the overweighted lives would increase with age.

• Korean Journal of Remote Sensing
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• v.35 no.3
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• pp.415-431
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• 2019

The satellite-viewed cloudiness, a ratio of cloudy pixels to total pixels ($C_{sat,\;prev}$), inevitably differs from the "ground-viewed" cloudiness ($C_{grd}$) due to different viewpoints. Here we develop an algorithm to retrieve the satellite-viewed, but adjusted cloudiness to $C_{grd} (C_{sat,\;adj})$. The key process of the algorithm is to convert the cloudiness projected on the plane surface into the cloudiness on the celestial hemisphere from the observer. For this conversion, the supplementary satellite retrievals such as cloud detection and cloud top pressure are used as they provide locations of cloudy pixels and cloud base height information, respectively. The algorithm is tested for Himawari-8 level 1B data. The $C_{sat,\;adj}$ and $C_{sat,\;prev}$ are retrieved and validated with $C_{grd}$ of SYNOP station over Korea (22 stations) and China (724 stations) during only daytime for the first seven days of every month from July 2016 to June 2017. As results, the mean error of $C_{sat,\;adj}$ (0.61) is less that than that of $C_{sat,\;prev}$ (1.01). The percent of detection for 'Cloudy' scenario of $C_{sat,\;adj}$ (73%) is higher than that of $C_{sat,\;prev}$ (60%) The percent of correction, the accuracy, of $C_{sat,\;adj}$ is 61%, while that of $C_{sat,\;prev}$ is 55% for all seasons. For the December-January-February period when cloudy pixels are readily overestimated, the proportion of correction of $C_{sat,\;adj$ is 60%, while that of $C_{sat,\;prev}$ is 56%. Therefore, we conclude that the present algorithm can effectively get the satellite cloudiness near to the ground-viewed cloudiness.