• Imaging Science in Dentistry
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• v.43 no.3
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• pp.163-169
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• 2013

Purpose: Tonsilloliths are calcifications found in the crypts of the palatal tonsils and can be detected on routine panoramic examinations. This study was performed to highlight the benefits of cone-beam computed tomography (CBCT) in the diagnosis of tonsilloliths appearing bilaterally on panoramic radiographs. Materials and Methods: The sample group consisted of 7 patients who had bilateral radiopaque lesions at the area of the ascending ramus on panoramic radiographs. CBCT images for every patient were obtained from both sides of the jaw to determine the exact locations of the lesions and to rule out other calcifications. The calcifications were evaluated on the CBCT images using Ez3D2009 software. Additionally, the obtained images in DICOM format were transferred to ITK SNAP 2.4.0 pc software for semiautomatic segmentation. Segmentation was performed using contrast differences between the soft tissues and calcifications on grayscale images, and the volume in mm3 of the segmented three dimensional models were obtained. Results: CBCT scans revealed that what appeared on panoramic radiographs as bilateral images were in fact unilateral lesions in 2 cases. The total volume of the calcifications ranged from 7.92 to $302.5mm^3$. The patients with bilaterally multiple and large calcifications were found to be symptomatic. Conclusion: The cases provided the evidence that tonsilloliths should be considered in the differential diagnosis of radiopaque masses involving the mandibular ramus, and they highlight the need for a CBCT scan to differentiate pseudo- or ghost images from true bilateral pathologies.

• Korean Journal of Environment and Ecology
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• v.5 no.1
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• pp.32-41
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• 1991

A survey of subalpine zone (altitude is 1,360-1,410m) in Mt. Chiri, was conducted using 25 sample plots of 500$m^2$ size. The classification by TWINSPAN and DCA ordination were applied to the study area in order to classify them into several groups based on woody plants and environmental variables. By TWINSPAN techniques, the plant community were divided into five groups by importance value of Abies nephrolepis. The dividing groups are Fraxinus rhynchophylla - Magnolia sieboldii community, Quercus mongolica - Rhododendron schlippenbachii community, Q. mongolica - F. rhynchophylla - Acer pseudo-sieboldianum community, Q. mongolica- A. nephrolepis- Rh. schlippenbachii community, and A. nephrolepis- Pinus densiflora - Rh. schlippenbachii community. The successional trends of tree species by both techniques seem to be from Q. mongolica to A. nephrolepis in the canopy layer. It was no difference between the stand scores of DCA and environmental variables.

• Journal of Korean Society of Forest Science
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• v.96 no.3
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• pp.251-258
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• 2007

Airborne Lidar (light detection and ranging) can be an effective alternative in forest inventory to overcome the limitations of conventional field survey and aerial photo interpretation. In this study, we attempt to develop methodologies to identify individual trees and to estimate tree height from airborne Lidar data. Initially, digital elevation model (DEM) data representing the exact ground surface were generated by removing non-ground returns from the multiple-return laser point clouds, obtained over the coniferous forest site of rugged terrain. Based on the canopy height model (CHM) data representing non-ground layer, individual tree heights are extracted through pseudo-grid method and moving window filtering algorithm. Comparing with field survey data and aerial photo interpretation on sample plots, the number of trees extracted from Lidar data show over 90% accuracy and tree heights were underestimated within 1.1m in average at two plantation stands of pine (Pinus koraiensis) and larch (Larix leptolepis).

• Journal of the Korean Magnetics Society
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• v.15 no.2
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• pp.61-66
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• 2005

In order to make submicron cell for spin-injection device, lift-off method using Pt stencil and wet etching was chosen. This approach allows batch fabrication of stencil substrate with electron-beam lithography. It simplifies the process between magnetic film stack deposition and final device testing, thus enabling rapid turnaround in sample fabrication. Submicron junctions with size of $200nm{\times}300nm$ and $500nm{\times}500nm$ 500 nm and pseudo spin valve structure of $CoFe(30{\AA})/Cu(100{\AA})/CoFe(120{\AA}$) was deposited into the nanojunctions. MR ratio was 0.8 and $1.1{\%}$, respectively and spin transfer effect was confirmed with critical current of $7.65{\times}10^7A/cm^2$.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.343-350
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• 2005

During the design of a successful digital watermarking systems, Pseudo-Noise(PN) sequences are widely used to modulate information bits into watermark signals. In this method, the number of bits that can be hidden within a small image by means of frequency domain watermarking is limited. In this paper, we show the possibility of introducing chaotic sequences into digital watermarking systems as potential substitutes to commonly used PN-sequences. And we propose a method that transforms the text to chaotic sequence. In our current implementation, we show how the sample text is expressed by an implied unit data(watermark) and the implied unit data is regenerated into the original left. Because we use this implied data as watermark for information hiding, we can insert much more watermark compared with previous method.

• Journal of Electrochemical Science and Technology
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• v.4 no.1
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• pp.34-40
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• 2013

The structural and electrochemical properties of $Li_{0.99}Ni_{0.46}Mn_{1.56}O_4$ ($Fd{\bar{3}}m$, disordered spinel) cathode material were studied and compared with stoichiometric $LiNi_{0.5}Mn_{1.5}O_4$ ($P4_332$, ordered spinel). First cycle discharge capacity of $Li_{0.99}Ni_{0.46}Mn_{1.56}O_4$ was similar to that of $LiNi_{0.5}Mn_{1.5}O_4$ at C/3 and 1C rate, but cycling performance of $Li_{0.99}Ni_{0.46}Mn_{1.56}O_4$ was better than that of $LiNi_{0.5}Mn_{1.5}O_4$ especially at high rate of 1C. This can be explained by performing synchrotron based in-situ XRD and results of GITT measurements. It is considered that faster lithium ion diffusion in the $Li_{0.99}Ni_{0.46}Mn_{1.56}O_4$ cathode results in the improvement of the rate capability. To study structural changes during cycling, synchrotron in-situ XRD patterns of both the samples were recorded at C/3 and 1C rate. Compared to stoichiometric $LiNi_{0.5}Mn_{1.5}O_4$, disordered $Li_{0.99}Ni_{0.46}Mn_{1.56}O_4$ spinel sample has pseudo one phase behavior and one step phase transition between two cubic phases. So, $LiNi_{0.5}Mn_{1.5}O_4$ would experience a much greater strain and stress, originating from the two phase transitions between three cubic phases and suffer from capacity loss during cycling especially at high rate.

• The Korean Journal of Applied Statistics
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• v.37 no.3
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• pp.381-393
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• 2024

This study investigates the impact of pseudonymization of personal information and its effect on the accuracy of data analysis. We quantitatively evaluated the relationship between the degree of pseudonymization and the accuracy of data analysis using logistic regression models, decision trees, and random forests. Through this, we confirmed that pseudonymizing sensitive information can realize personal information protection without significantly damaging data quality. However, we recognized limitations such as single sample data and consistent application of pseudonymization ratios. To overcome these limitations, additional research on diverse datasets is necessary to strengthen the generalizability of results. Moreover, we propose developing and applying methodologies to find optimal pseudonymization ratios for individual variables. The results from this study provide new insights into maintaining usability of data while achieving regulatory compliance and personal information protection.

• Journal of Korean Society of Forest Science
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• v.95 no.4
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• pp.443-452
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• 2006

This study was conducted to investigate the site and growth characteristics of Mackia amurensis stand in natural forest of Mt. Joongwang, Pyongchang-Gun, Gangwon-Do, Korea. The 28 sample plots ($30m{\times}30m$) were established to examine the vegetation and site characteristics for M. amurensis stand. Stem analysis was performed on two sample trees for each of the 5 plots situated at intervals of 100 m by altitude. M. amurensis trees were mainly distributed at the ridge and the slope facing north, with altitudes ranging from 790 to 1,170 m. The M. amurensis grew at relatively deep A-layer of soil with high moisture but infertile. Dominant species with M. amurensis were Quercus mongolica, Fraxinus rhynchophylla, Acer pseudo-sieboldianum, A. pictum subsp. mono, Ulmus davidiana var., japonica, Tilia amurensis, and Populus davidiana. TWINSPAN classified four communities in Mt. Joongwang area; M. amurensis-P. davidiana community (xeric type), M. amurensis-U. davidiana var. japonica community (xeric type), M. amurensis-T. amurensis community (moist type), and M. amurensis-Styrax obassia community (moist type). According to the community type, trees per ha were more abundant in the area of the moist types than the xeric types. Height growth of M. amurensis increased with increasing ages until 10 years, and then decreased thereafter, especially at altitude of 1,020m. M. amurensis showed rapid early growth of height and volume, indicating possible high biomass production under enough light. Growth of M. amurensis increased greatly at about 40 years if released from severe competitions. The rotation age of natural M. amurensis stand was expected for above 50 years.

• Food Engineering Progress
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• v.13 no.2
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• pp.138-146
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• 2009

The crude polysaccharide fraction from fruit body of Auricularia auricula were obtained by using hot water extraction and ethanol precipitation. As the crude polysaccharide fraction contained the brownish dark colored compounds, the adsorption study of pigments from the crude polysaccharide using activated carbon was carried out. The pigment compounds showed an absorption characteristic with $\lambda_{max}$ of 230 nm and the absorbance at 230 nm was taken as color intensity. Adsorption capacity of pigment depended on increase of the activated carbon to sample loading ratio. The adsorption capacity increased with increase of pH and temperature in the pH range of 3.0-7.0 and temperature range of 25-40$^{\circ}C$, but decreased in the temperature range of 40-70$^{\circ}C$. The optimum capacity was obtained at addition of 16.7 mg activated carbon per mL sample solution (concentration = 3 mg/mL) at pH of 7.0 and temperature of 40$^{\circ}C$. Treatment for 10 min was sufficient to achieve the 80% decolorization and 1.25 fold purification of polysaccharide. Langmuir isotherm and pseudo second-order kinetic model provided the best fitting for adsorption of the brownish dark colored compounds onto powdered active carbon. The activation energies of adsorption from the Langmuir isotherm parameter in the ranges of 25-40$^{\circ}C$ and 40-70$^{\circ}C$ was -2.54 and 4.38 kcal/g, respectively. The results of low activation energy also indicated that the adsorption process was a physical adsorption which was controlled by diffnsion.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.9
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• pp.514-526
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• 2004

Microarray is a new technique for gene expression experiment, which has gained biologist's attention for recent years. This technology enables us to obtain hundreds and thousands of expression of gene or genotype at once using microarray Since it requires manual work to analyze patterns of gene expression, we want to develop an effective and automated tools to analyze microarray image. However it is difficult to analyze DNA chip images automatically due to several problems such as the variation of spot position, the irregularity of spot shape and size, and sample contamination. Especially, one of the most difficult problems in microarray analysis is the block and spot addressing, which is performed by manual or semi automated work in all the commercial tools. In this paper we propose a new algorithm to address the position of spot and block using a new concept of regular structure grid searching. In our algorithm, first we construct maximal I-regular sequences from the set of input points. Secondly we calculate the rotational angle and unit distance. Finally, we construct I-regularity graph by allowing pseudo points and then we compute the spot/block address using this graph. Experiment results showed that our algorithm is highly robust and reliable. Supplement information is available on http://jade.cs.pusan.ac.kr/~autogrid.