• Clinical and Experimental Pediatrics
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• v.51 no.5
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• pp.518-522
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• 2008

Purpose : The purpose of this study was to investigate the prevalence of enuresis in association with voiding habits and socioeconomic status in elementary school children. Methods : A dynamic survey was done of 1,514 students from two elementary schools in Suwon, Korea in December 2006. Data regarding gender, age, height and weight, voiding habits, and monthly family incomes were gathered and analyzed to discover any correlation with the incidence of enuresis. The percentile value of height or weight was extrapolated from the standard population curve. Results : Among 1,514 children, 1,063 (70.2%) answered and returned the questionnaires. Overall, the prevalence of enuresis was 8.7% and there was no difference between the public (8.8%) and private school (8.7%). The family incomes of the students from the two schools differed greatly from each other, but there was no difference in the prevalence of enuresis between the two schools. Children with a habit of void-holding showed a higher prevalence of enuresis. No significant correlation was found between the prevalence of enuresis and the height and weight percentile of children. Experience with hospital visits was low among enuretic children (20.8%), suggesting that Korean parents tend to neglect treatment of enuresis for their children. The prevalence of enuresis decreased by 2.0% each year, as school children aged. Conclusion : The overall prevalence of enuresis among elementary school children in Suwon district was 8.7%. The 12.1% prevalence of enuresis at the seven years came down gradually, to be nil at the age of 13. Infrequent urination or void-holding was assumed to be one of the important factors causing enuresis in elementary school children.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.1
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• pp.115-123
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• 1990

The purpose of this study was to examine the uses of coal ash as a type of construction material. The methods of examination were chemical anlysis, soil laboratory test and the soil vibration test. Materials used were coal ash obtained as a by-product from 5 thermal power plants in Yongdong, Yongwol, Sochon(anthracite coal) and in Samchonpo and Honam (bituminous coal). Over 70% of the coal ash consisted of silica and alumina. The fly ash grain size showed a uniform distribution from fine-sand to silt, and that of the bottom ash showed from sand to gravel. The specific gravity and density of the coal ash were low. The long term strength increased gradually due to the self-setting property resulting from pozzolanic activity. The shear strength was higher than that of general soil. Cohesion and optimum moisture content of anthracite coal ash were higher than bituminous coal ash, whereas the maximum dry density was higher in bituminous coal ash. The coal ash dynamic Young's modulous curve range was similar to that of general soil. Of the results from the soil vibration test by car-running, the size relative acceleration level in the ash pond was higher than that of natural ground, but the damping ratio was lower than that of natural ground near the ash pond. The coal ash has more advantageous engineering properties than general soil with particles of the same size. For example, the California Bearing Ratio of the bottom ash at both Yongdong and Yongwol was 77~137%. Therefore we expect that if further study is done, coal ash can be used as a construction material when reclaiming seashore, construction embankments, road construction, making right-weight aggregate, or as a general construction material.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.215-224
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• 2013

We clarified the background for establishment of vegetation by comparing the spatial distribution maps of vegetation and substrate on a gravel bar in the Bangtae stream located on Inje-gun of Gangwon-do, the central eastern Korea. The total vegetation coverage was higher in the interior and lower in the marginal parts of the gravel bar. Spatial distribution of vegetation on the longitudinal section of the gravel bar tended to be arranged in the order of shrub, subtree, and tree dominated vegetation types from the front (upstream) toward the rear (downstream) parts. Coverage of the herbaceous plants was higher in the central and rear parts and lower in the front and right parts of the gravel bar. Vegetation height was higher in the rear part and became lowered as move toward the front part. Substrate was distributed in the order of boulder, gravel, sand, and boulder from the front toward the rear parts. Ordination of stands based on vegetation data was arranged in the order of annual plant, perennial herb, shrub, and tree dominated vegetation as move from the right to the left parts on the axis I. Species richness was higher in the order of Pinus densiflora community, Phragmites japonica community, Salix gracilistyla community, Fraxinus rhynchophylla community, annual plant dominated vegetation, and Prunus padus for. padus community based on the species rank-abundance curve. The order based on the Shannon's index was some different; diversity of Phragmites japonica community and Salix gracilistyla community, which showed higher dominance degree, were low differently from species richness. In conclusion, it was evaluated that the gravel bar newly established toward the upstream and vegetation dynamics of the gravel bar seemed to follow ecosystem mechanisms of succession. As were shown in the above results, the Bangtae stream corresponded to the upstream and thereby particle size of substrate was big. Therefore, they move by rolling and are accumulated for the upstream. Vegetation types were arranged in the order of woodland, shrub-land and grassland from the rear toward the front parts of the gravel bar and thereby reflected the formation process of the bar. However, the gravel bar is disturbed frequently by not only the running water but also the suspended sand as the dynamic space. Such disturbances cause habitat diversity and consequently led to high biodiversity.

• The Korean Journal of Nuclear Medicine
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• v.31 no.1
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• pp.90-101
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• 1997

The purpose of this study is to evaluate the diagnostic accuracy of various quantitative indices for the differentiation of benign from malignant primary soft tissue tumors by FDG-PET. A series of 32 patients with a variety of histologically or clinically confirmed benign (20) or malignant (12) soft tissue lesions were evaluated with emission whole body (5min/bed position) PET after injection of [$^{18}F$]FDG. Regional 20min transmission scan for the attenuation correction and calculation of SUV was performed in 16 patients (10 benign, 6malignant) followed by dynamic acquisition for 56min. Postinjection transmission scan for the attenuation correction and calculation of SUV was executed in the other 16 patients (10 benign, 6 malignant). The following indices were obtained. the peak and average SUV (pSUV, aSUV) of lesions, tumor-to-background ratio acquired at images of 51 min p.i. ($TBR_{51}$), tumor-to-background ratio of areas under time-activity curves ($TBR_{area}$) and the ratio between the activities of tumor ROI at 51 min p. i. and at the time which background ROI reaches maximum activity on the time-activity curves ($T_{51}/T_{max}$). The pSUV, aSUV, $TBR_{51}$, and $TBR_{area}$ in malignant lesions were significantly higher than those in benign lesions. We set the cut-off values of pSUV, aSUV, $TBR_{51},\;TBR_{area}$ and $T_{51}/T_{max}$ for the differentiation of benign and malignant lesions at 3.5, 2.8, 5.1, 4.3 and 1.55, respectively. The sensitivity, specificity and accuracy were 91.7%, 80.0%, 84.4% by pSUV and aSUV, 83.3%, 85.0%, 84.4% by $TBR_{51}$, 83.3%, 100%, 93.8% by $TBR_{area}$ and 66.7%, 70.0%, 68.8% by $T_{51}/T_{max}$. The time-activity curves did not give additional information compared to SUV or TBR. The one false negative was a case with low-grade fibrosarcoma and all four false positives were cases with inflammatory change on histology. The visual, analysis of FDG-PET also detected the metastatic lesions in malignant cases with comparable accuracy In conclusion, all pSUV, aSUV, $TBR_{51}$, and $TBR_{area}$ are useful metabolic semi-quantitative indices with good accuracy for the differentiation of benign from malignant soft-tissue lesions.

• Radiation Oncology Journal
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• v.23 no.4
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• pp.217-222
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• 2005

Purpose: To develop the respiration simulating phantom with thermocouple for evaluating 4D radiotherapy such as gated radiotherapy breathing control radiotherapy and dynamic tumor tracking radiotherapy. Materials and Methods: The respiration monitoring mask(ReMM) with thermocouple was developed to monitor the patient's irregular respiration. The signal from ReMM controls the simulating phantom as organ motion of patients in real-time. The organ and the phantom motion were compared with its respiratory curves to evaluate the simulating phantom. ReMM was used to measure patients' respiration, and the movement of simulating phantom was measured by using $RPM^{(R)}$. The fluoroscope was used to monitor the patient's diaphragm motion. relative to the organ motion, respectively. The standard deviation of discrepancy between the respiratory curve and the organ motion was 8.52% of motion range. Conclusion: Patients felt comfortable with ReMM. The relationship between the signal from ReMM and the organ motion shows strong correlation. The phantom simulates the organ motion in real-time according to the respiratory signal from the ReMM. It is expected that the simulating phantom with ReMM could be used to verify the 4D radiotherapy.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.5-9
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• 2004

In this paper, we studied the OCT(Optical Coherence Tomography) system which it has been extensively studied because of having some advantages such as high resolution cross-sectional images, low cost, and small size configuration. A basic principle of OCT system is Michelson interferometer. The characteristics of light source determine the resolution and the transmission depth. As a results, the light source have a commercial SLD with a central wavelength of 1,285 nm and FWHM(Full Width at Half Maximum) of 35.3 nm. The optical delay line part is necessary to equal of the optical path length with scattered light or reflected light from sample. In order to equal the optical path length, the stage which is attached to reference mirror is moved linearly by step motor And the interferometer is configured with the Michelson interferometer using single mod fiber, the scanner can be focused of the sample by using the reference arm. Also, the 2-dimensional cross-sectional images were measured with scanning the transverse direction of the sample by using step motor. After detecting the internal signal of lateral direction at a paint of sample, scanner is moved to obtain the cross-sectional image of 2-demensional by using step motor. Photodiode has been used which has high detection sensitivity, excellent noise characteristic, and dynamic range from 800 nm to 1,700 nm. It is detected mixed small signal between noise and interference signal with high frequency After filtering and amplifying this signal, only envelope curve of interference signal is detected. And then, cross-sectional image is shown through converting this signal into digitalized signal using A／D converter. The resolution of the OCT system is about 30$\mu\textrm{m}$ which corresponds to the theoretical resolution. Also, the cross-sectional image of ping-pong ball is measured. The OCT system is configured with Michelson interferometer which has a low contrast because of reducing the power of feedback interference light. Such a problem is overcomed by using the improved inteferometer. Also, in order to obtain the cross-sectional image within a short time, it is necessary to reduce the measurement time for improving the optical delay line.

• Journal of architectural history
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• v.1 no.1 s.1
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• pp.68-87
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• 1992

This study is the conditions of location according to formed the times in the clan village. The results of this study are as follows ; 1. in the 15th century, the characterestics of the village established residencial place where mountain stream flowed surrounded by the mountain and deep in the mountains with superior quality land. That's because Sa-dae-bu put equal importance on beautiful scenery and practical benefit for living. Stream House provided economical foundation for Sa-dae-bu to be able to keep confucial manners by putting limit their economic status to small medium sized land owner. Topographical condition such as valley or hollow separated from the exterior maintained unification of consanguineous village in self sufficient farming society and held on to independent territory against external to be able to stay away from turbulent days so that they formed residential area of Sa-dae-bu clan. And the valley where flowed clean water was considered as the connection of continuous place where distinctiveness of form in each curve and and factor of calm and dynamic scenery of the clean stream. Scholars in the middle of Chosun Dynasty located in the utopia as place for confucious retirement to study, a place for refinement by combination with the nature or as a way of spacial practice based on Confucious view of nature. 2. in the 16th-l7th century, Most of existing consanguineous villages adopt deep in the mountains for refuge. at that place, upward rank was established by settlement of the ancestor who entered in the village first, the principal was placed in the center of the village and since descendants became numerous, it was serialized as the space of descendants. So, it was arranged in the order of social rank. Most of the villages showed development step by step started from precaution by apperance of the mountain to the lower part. It's because the topography of valley around the village worked as the natural hedge against external force and genealogy of the clan, regularity of social status, order of entrance into the village were reflected into residencial destribution. Also, order of the rank coincided with the one of aspects on geomancy. Genealogical rank within the village represented spacial rank. Houses of descendants and branch families were placed lower than the principal which showed worship to the principal. 3. In 18th century after, as the village was settled nearby cultivated land considering economical loss caused by long distance between residencial area and cultivated land, direction of sect followed by development of village expanded from the front part of the village to the rear part. The principal that was poped out to the front presented frontage over exterior. Therefore, residencial area of branch families expanded to the rear starting from the principal. This represented a slice of social structure at that time. after 18th century, spirit was percieved superior over material, After then, development of cultivation and expantion of land created difference of economic strength within one village. In order to maintain and show off the status of Yang-ban, economic power of indigenous land owner became fundamental, so, sense to worship and to keep the principal became weak eventually. Taking advantage of that situation, residencial area of branch family expanded to the rear part of the principal which showed dual disposition conflicted with each other. However, these clan rules were destroyed and new rules were created after 18th century because of the situation and consciousness at that time.

• Journal of the Korean Society of Radiology
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• v.12 no.6
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• pp.755-762
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• 2018

The purpose of this study was to compare the FA(faractional anisotropy) and ADC(apparent diffusion coefficient) values, which were derived from diffusion tensor imaging in breast cancer patients. The diffusion gradient used in this study was derived from quantitative diffusion indices using 20 directions(b-value, 0 and $1,000s/mm^2$). Quantitative analysis was analyzed using Pearson's correction and qualitative analysis using for correction coefficients. As a result, $FA_{min}$, $FA_{mean}$ and $FA_{max}$ were $0.098{\pm}0.065$, $0.302{\pm}0.142$ and $0.634{\pm}0.236$, respectively(p > 0.05). The $ADC_{min}$, $ADC_{mean}$ and $ADC_{max}$ were $0.741{\pm}0.403$, $1.095{\pm}0.394$ and $1.530{\pm}0.447$, respectively(p > 0.05). The $FA_{min}$, $FA_{mean}$, and $FA_{max}$ mean values were $0.132{\pm}0.050$, $0.418{\pm}0.094$, and $0.770{\pm}0.164$ for Category 6 and Kinetic Curve Pattern III, respectively. $ADC_{min}$, $ADC_{mean}$, and $ADC_{max}$ were $0.753{\pm}0.189$, $1.120{\pm}0.236$, and $1.615{\pm}0.372$, respectively. Quantitative analysis showed negative correlation between $ADC_{mean}-FA_{mean}$ and $ADC_{max}-FA_{max}$(p = 0.001, 0.003). The qalitative analysis showed ADC 0.628(p = 0.001), FA 0.620(p = 0.001) in the internal evaluations, ADC 0.677(p = 0.001), FA 0.695(p = 0.001) in external evaluations. In conclusion, based on the morphological examination, time to signal intensity graph is the form of wash-out(pattern III) in the dynamic contrast enhance examination, As a result, the $ADC_{mean}$ $1.120{\pm}0.236$ and $FA_{mean}$ values were $0.032{\pm}0.142$ with a negative correlation (Y=1.44-1.12X). Therefore, If we understand the shape of time to signal intensity graph and the relationship between ADC and FA, It will be a criterion for distinguishing malignant diseases in breast cancer.

• Journal of the Korean Society of Radiology
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• v.83 no.1
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• pp.149-161
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• 2022

Purpose To investigate the correlation between computer-aided diagnosis (CAD) parameters in 3-tesla (T) MRI and pathologic immunohistochemical (IHC) markers in invasive carcinoma of no special type (NST). Materials and Methods A total of 94 female who were diagnosed with NST carcinoma and underwent 3T MRI using CAD, from January 2018 to April 2019, were included. The relationship between angiovolume, curve peak, and early and late profiles of dynamic enhancement from CAD with pathologic IHC markers and molecular subtypes were retrospectively investigated using Dwass, Steel, Critchlow-Fligner multiple comparison analysis, and univariate binary logistic regression analysis. Results In NST carcinoma, a higher angiovolume was observed in tumors of higher nuclear and histologic grades and in lymph node (LN) (+), estrogen receptor (ER) (-), progesterone receptor (PR) (-), human epidermal growth factor 2 (HER2) (+), and Ki-67 (+) tumors. A high rate of delayed washout and a low rate of delayed persistence were observed in Ki-67 (+) tumors. In the binary logistic regression analysis of NST carcinoma, a high angiovolume was significantly associated with a high nuclear and histologic grade, LN (+), ER (-), PR (-), HER2 (+) status, and non-luminal subtypes. A high rate of washout and a low rate of persistence were also significantly correlated with the Ki-67 (+) status. Conclusion Angiovolume and delayed washout/persistent rate from CAD parameters in contrast enhanced breast MRI correlated with predictive IHC markers. These results suggest that CAD parameters could be used as clinical prognostic, predictive factors.

• Journal of Global Scholars of Marketing Science
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• v.18 no.2
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• pp.223-252
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• 2008

In this study, we attempt to propose a choice-based diffusion model with switching cost, which can be used to forecast the dynamic substitution and competition among previous and new products at both individual-level and aggregate level, especially when market data for new products is insufficient. Additionally, we apply the proposed model to the empirical case of substitution and competition among Analog Cable TV that represents previous fixed charged broadcasting service and Digital Cable TV and Internet Protocol TV (IPTV) that are new ones, verify the validities of our proposed model, and finally derive related empirical implications. For empirical application, we obtained data from survey conducted as follows. Survey was administered by Dongseo Research to 1,000 adults aging from 20 to 60 living in Seoul, Korea, in May of 2007, under the title of 'Demand analysis of next generation fixed interactive broadcasting services'. Conjoint survey modified as follows, was used. First, as the traditional approach in conjoint analysis, we extracted 16 hypothetical alternative cards from the orthogonal design using important attributes and levels of next generation interactive broadcasting services which were determined by previous literature review and experts' comments. Again, we divided 16 conjoint cards into 4 groups, and thus composed 4 choice sets with 4 alternatives each. Therefore, each respondent faces 4 different hypothetical choice situations. In addition to this, we added two ways of modification. First, we asked the respondents to include the status-quo broadcasting services they subscribe to, as another alternative in each choice set. As a result, respondents choose the most preferred alternative among 5 alternatives consisting of 1 alternative with current subscription and 4 hypothetical alternatives in 4 choice sets. Modification of traditional conjoint survey in this way enabled us to estimate the factors related to switching cost or switching threshold in addition to the effects of attributes. Also, by using both revealed preference data(1 alternative with current subscription) and stated preference data (4 hypothetical alternatives), additional advantages in terms of the estimation properties and more conservative and realistic forecast, can be achieved. Second, we asked the respondents to choose the most preferred alternative while considering their expected adoption timing or switching timing. Respondents are asked to report their expected adoption or switching timing among 14 half-year points after the introduction of next generation broadcasting services. As a result, for each respondent, 14 observations with 5 alternatives for each period, are obtained, which results in panel-type data. Finally, this panel-type data consisting of $4{\ast}14{\ast}1000=56000$observations is used for estimation of the individual-level consumer adoption model. From the results obtained by empirical application, in case of forecasting the demand of new products without considering existence of previous product(s) and(or) switching cost factors, it is found that overestimated speed of diffusion at introductory stage or distorted predictions can be obtained, and as such, validities of our proposed model in which both existence of previous products and switching cost factors are properly considered, are verified. Also, it is found that proposed model can produce flexible patterns of market evolution depending on the degree of the effects of consumer preferences for the attributes of the alternatives on individual-level state transition, rather than following S-shaped curve assumed a priori. Empirically, it is found that in various scenarios with diverse combinations of prices, IPTV is more likely to take advantageous positions over Digital Cable TV in obtaining subscribers. Meanwhile, despite inferiorities in many technological attributes, Analog Cable TV, which is regarded as previous product in our analysis, is likely to be substituted by new services gradually rather than abruptly thanks to the advantage in low service charge and existence of high switching cost in fixed charged broadcasting service market.