• Journal of radiological science and technology
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• v.39 no.2
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• pp.149-156
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• 2016

Measurement of cardiac blood flow using the magnetic resonance imaging has been limited due to breathing and involuntary movements of the heart. The present study attempted to improve the accuracy of cardiac blood flow testing through phase contrast magnetic resonance imaging by presenting the adequate breathing method and imaging variables by comparing the measurement values of cardiac blood flow. Each was evaluated by comparing the breath hold retrospective 1NEX and non breath hold retrospective 1-3NEX in the ascending aorta and descending aorta. As a result, the average blood flow amount/velocity of the breath hold retrosepctive 1NEX method in the ascending aorta were $96.17{\pm}19.12ml/sec$, $17.04{\pm}4.12cm/sec$ respectively, which demonstrates a statistically significant difference(p<0.05) with the non-breath hold retrospective method 1NEX of $72.31{\pm}13.27ml$ and $12.32{\pm}3.85$. On the other hand, the average 2NEX blood flow and mean flow velocity is $101.90{\pm}24.09$, $16.84{\pm}4.32$, 3NEX $103.06{\pm}25.49$, $16.88{\pm}4.19$ did not show statistically significant differences(p>0.05).The average blood flow amount/ velocity of the breath hold retrospective 1NEX method in the descending aorta were $76.68{\pm}19.72ml/s$, and $22.23{\pm}4.8$, which did not demonstrate a significant difference in comparison to non-breath hold retrospective method 1-3 NEX. Therefore, the non breath hold retrospective method does not significantly differ in terms of cardiac blood flow in comparison with the breath hold retrospective method in accordance with the increase of NEX, so pediatric patients or patients who are not able to breathe well must have the diagnostic value of their cardiac blood flow tests improved.

• Korean Journal of Remote Sensing
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• v.27 no.5
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• pp.613-623
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• 2011

This study assessed the feasibility to apply Two-band and Three-band reflectance models for chlorophyll-a estimation in turbid productive waters whose scale is smaller and narrower than ocean using a high spatial resolution image. Those band ratio models were successfully applied to analyzing chlorophyll-a concentrations of ocean or coastal water using Moderate Imaging Spectroradiometer(MODIS), Sea-viewing Wide Field-fo-view Sensor(SeaWiFS), Medium Resolution Imaging Spectrometer(MERIS), etc. Two-band and Three-band models based on band ratio such as Red and NIR band were generally used for the Chl-a in turbid waters. Two-band modes using Red and NIR bands of RapidEye image showed no significant results with $R^2$ 0.38. To enhance a band ratio between absorption and reflection peak, We used red-edge band(710 nm) of RapidEye image for Twoband and Three-band models. Red-RE Two-band and Red-RE-NIR Three-band reflectance model (with cubic equation) for the RapidEye image provided significance performances with $R^2$ 0.66 and 0.73, respectively. Their performance showed the 'Approximate Prediction' with RPD, 1.39 and 1.29 and RMSE, 24.8, 22.4, respectively. Another three-band model with quadratic equation showed similar performances to Red-RE two-band model. The findings in this study demonstrated that Two-band and Three-band reflectance models using a red-edge band can approximately estimate chlorophyll-a concentrations in a turbid river water using high-resolution satellite image. In the distribution map of estimated Chl-a concentrations, three-band model with cubic equation showed lower values than twoband model. In the further works, quantification and correction of spectral interferences caused by suspended sediments and colored dissolved organic matters will improve the accuracy of chlorophyll-a estimation in turbid waters.

• Korean Journal of Remote Sensing
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• v.30 no.2
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• pp.185-205
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• 2014

SAR ground moving target indicator (GMTI) has long been an important issue for SAR advanced applications. As spatial resolution of space-borne SAR system has been significantly improved recently, the GMTI becomes a very useful tool. Various GMTI techniques have been developed particularly using multi-channel SAR systems. It is, however, still problematic to detect ground moving targets within single channel SAR images while it is not practical to access high resolution multi-channel space-borne SAR systems. Once a ground moving target is detected, it is possible to retrieve twodimensional velocities of the target from single channel space-borne SAR with an accuracy of about 5 % if moving faster than 3 m/s. This paper presents a quick-and-dirty method for detecting ground moving targets from single channel SAR single-look complex (SLC) images by differentiation. Since the signal powers of derivatives present Doppler centroid and rate, it is very efficient and effective for detection of non-stationary targets. The derivatives correlate well with velocities retrieved by a precise method with a correlation coefficient $R^2$ of 0.62, which is well enough to detect the ground moving targets. While the approach is theoretically straightforward, it is necessary to remove the effects of residual Doppler rate before finalizing the ground moving target candidates. The confidence level of results largely depends on the efficiency and effectiveness of the residual Doppler rate removal method. Application results using TerraSAR-X and truck-mounted corner reflectors validated the efficiency of the method. While the derivatives of moving targets remain easily detectable, the signal energy of stationary corner reflectors was suppressed by about 18.5 dB. It results in an easy detection of ground targets moving faster than 8.8 km/h. The proposed method is applicable to any high resolution single channel SAR systems including KOMPSAT-5.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.3
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• pp.144-150
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• 2006

Chemical characteristics and their interrelationships of 156 soils included by 74 sandy loam and 82 loam soils collected from plastic film house in Chungbuk area were investigated from 1998 to 2001. Seventeen chemical properties including pH, organic matter (OM), electrical conductivity (EC), inorganic nitrogen, available phosphorus, exchangeable cations, CEC, etc., were analyzed by correlation, standardized partial regression coefficient, and principal factor analysis. Standardized partial regression coefficients of chemical properties were estimated to determine the degree of contribution of EC and OM contents in soils. Principal factor analysis was applied to classify the studied chemical properties into different groups having similar chemical properties. The pH of experimental soils ranged from 4.24 to 7.14 and 4.95 to 7.35 for loam and sandy loam soils, respectively. The EC of soils varied from 0.93 to $15.65dS\;m^{-1}$ for loam and $0.91{\sim}22.30dS\;m^{-1}$ for sandy loam soils, respectively with significant differences among them. The EC measured by 1:5 $H_2O$ dilution method and saturation method were significantly related with 8.163 and 8.599 as the slopes of regression equation for loam and sandy loam soils, respectively. These slopes more than 8.0 in this regression equation was higher than the slope of 5.0 that is estimated from dilution coefficient suggesting that EC measured by 1:5 dilution method might be erratic. The standardized partial regression coefficient of different chemical properties for the estimation of EC was in the order of $NO_3{^-}$ > $Cl^-$ > OM > exchangeable Mg for loam soils and $NO_3{^-}$ > exchangeable Mg > $Cl^-$ for sandy loam soils. Contribution order of the chemical properties based on standardized partial regression coefficient differed 1:5 dilution method and saturation method, indicating that different chemical compounds might be present in the extract solutions of these two methods. Consequently the measurement of EC by saturation method was thought be still better for estimation of chemical property because accuracy of EC measurement by 1:5 dilution method can't be improved by any specific coefficient for adjustment of EC. Regardless of differences in soil textures and extraction methods, correlation coefficients between EC and the other chemical properties were routinely in the order of $NO_3{^-}$ > $Cl^-$ > degree of base saturation > exchangeable Mg > exchangeable Ca > $SO{_4}^{2-}$. The principal factor analysis revealed four factor groups of the chemical properties studied. The groups for sandy loam were as follows; ; 1. salt components, 2. soil reaction components, 3. fixed and adsorption components, 4. CEC components. The groupings of loam soils were similar to sandy loam except that exchangeable Na substituted the CEC of sandy loam.

• Radiation Oncology Journal
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• v.17 no.4
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• pp.321-328
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• 1999

Purpose : Total body irradiation (TBI) or whole body irradiation is used to acquire immune suppression, to treat malignant lymphoma and leukemia, and as an conditioning regimen for bone marrow transplantation. For these purposes, many methods were developed to obtain homogenous dose distribution. The objective of this study was to analyze and confirm the accuracy and the homogeneity of the treatment setup, the parallel opposed lateral technique, currently used in Seoul National University Hospital. Materials and Metheods : Surface dose data, measured with a thermoluminescent dosimeter, of 8 patients among 10 patients, who were given total body irradiation with the parallel opposed lateral technique between September 1996 to August 1998, at Seoul National University Hospital were analyzed. Surface doses were measured at the head, neck, axilla, thigh, and ankle level. Surface and midline doses were measured with similar set-up and technique in the Humanoid phantom. Results : Measured surface doses relative to prescribed dose for the head, neck, axilla, thight, and ankle leve were $91.3{\pm}7.8,{\;}98.3{\pm}7.5,{\;}95.1{\pm}6.3,{\;}98.3{\pm}5.5$, and $95.3{\pm} 6.3\%$, respectively. The midline doses of the head, neck, axilla, thigh, and ankle level estimated from the surface-to-midline ratios in the Humanoid Phantom were $103.4{\pm}9.0,{\;}107.8{\pm}10.5,{\;}91.1{\pm}6.1,{\pm} 93.8{\pm}4.5,{\;}and{\;}104.5{\pm}9.3\%$, respectively. Measured surface doses and estimated midline doses ranged from $-8.9\%$ to $+7.8\%$. Midline doses at the neck and the axilia level deviated more than $5\%$ from the prescribed doses. The difference of the estimated midline doses at the neck and the axilla level and the actual doses were attributed to the thickness differences between the Humanoid phantom and the patients. Conclusion Distribution of the midline doses as well as the suface doses were measured to be within $-8.7\~{\pm}7.8\%$ range. Actual dose distribution in the patient is expected to be better than the measured dose range mainly attributed to thickness difference between the patient and the Humanoid phantom.

• Radiation Oncology Journal
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• v.17 no.1
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• pp.78-83
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• 1999

Purpose : We have compared the characteristics of Siemens virtual wedge device with physical wedges for clinical application. Materials and Methods : We investigated the characteristics of virtual and physical wedges for various wedge angles (15, 30, 45, and 60$^{\circ}$) using 6- and 15MV photon beams. Wedge factors were measured in water using an ion chamber for various field sizes and depths. In case of virtual wedge device, as upper jaw moves during irradiation, wedge angles were estimated by accumulated doses. These measurements were performed at off-axis points perpendicular to the beam central axis in water for a 15cm${\times}$20cm radiation field size at the depth of loom. Surface doses without and with virtual or physical wedges were measured using a parallel plate ion chamber at surface. Field size was 15cm H20cm and a polystyrene phantom was used. Results : For various field sizes, virtual and physical wedge factors were changed by maximum 2.1% and 3.9%) , respectively. For various depths, virtual and physical wedge factors were changed by maximum 1.9% and 2.9%, respectively. No major difference was found between the virtual and physical wedge angles and the difference was within 0.5$^{\circ}$ . Suface dose with physical wedge was reduced by maximum 20% (x-ray beam :6 MV, wedge angle:45$^{\circ}$, 550: 80 cm) relative to one with virtual wedge or without wedge. Conclusions : Comparison of the characteristics of Siemens virtual wedge device with physical wedges was performed. Depth dependence of virtual wedge factor was smaller than that of physical wedge factor. Virtual and physical wedge factors were nearly independent of field sizes. The accuracy of virtual and physical wedge angles was excellent. Surface dose was found to be reduced using physical wedge.

• Journal of Cadastre & Land InformatiX
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• v.48 no.1
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• pp.139-151
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• 2018

The National Base Map construction consists of the regular correction work of dividing the whole country into two regions and carrying out the modification Plotting by aerial photographs every two years as well as the real time updating work of correcting the major change feature within two weeks by the field survey and the As-Built Drawing. In the case of the Building Layout Drawing of Korea Real estate Administration intelligence System(KRAS) used for real time updating work of the National base map, the coordinate transformation error is included in the positional error when applied to the National Base Map based on the World Geodetic Reference System as the coordinate system based on the Regional Geodetic Reference System. In addition, National Base Map is registered based on the outline(eaves line) of the building in the Digital Topographic Map, and the Cadastral and Architecture are registered based on the building center line. Therefore, the Building Object management standard is inconsistent. In order to investigate the improvement method, the network RTK survey was conducted directly on a location of the Building Layout Drawing of Korea Real estate Administration intelligence System(KRAS) and the problems were analyzed by comparing with the plane plotting position reference in National Base Map. In the case of the general structure with the difference on the Building center line and the eaves line, beside the location information was different also the difference in the ratio of the building object was different between Building center line and the eave. In conclusion, it is necessary to provide the Base data of the double layer of the Building center line and the outline of the building(eaves line) in order to utilize the Building Layout Drawing of Korea Real estate Administration intelligence System(KRAS). In addition, it is necessary to study an organic map update process that can acquire the up-to-dateness and the accuracy at the same time.

• Journal of Korean Academy of Nursing Administration
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• v.4 no.1
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• pp.247-275
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• 1998

The purpose of this study was to offer the results of content analysis and qualitative study that explored the perceptions about quality nursing care of patients and families as consumers and to identify the implications of this study for quality nursing care management and research. The data was collected from 12 adult patients and 9 families who were admmitted at medical and surgical nursing unit of one university hospital in Seoul from October, 1996 to January, 1997. Research participants were asked to response "what do you think quality nursing care?" and similar questions during the interviews was performed. Data were analyzed using open coding and content analysis with frequencies and percents of attributes of quality nursing care. Attributes of quality nursing care and meaning of quality nursing care that patients and families perceived were explored. 1. The attributes of quality nursing care that patient and families perceived were categorized into 56 attributes. The highest response rate among the attributes was 'one's heart at ease' (76.2%), and the next high response rates were ranked in order 'consideration' , 'care about' (each 61.9% 'expert skill' (57.1%), 'deal with problem promptly' , 'information offer' (42.9%), 'intimate feeling' (38.1%), 'smile' 'service spirit' , 'do one's best' (each 33.3%), 'frequent visit' (23.8%), 'observe the time' (23.8%), 'direct nursing care' , 'speaking warmly' , give a hope' , 'address kindly' , 'a sense of duty' , 'good facilities' (each 19.0%), 'inquire after a patient health' , 'patient-centered nursing care' , 'showing an example' , 'professional knowledge' , 'careless moraly patient' , 'give encourage to patients' , 'good answer a question' (each 14.3%), 'do not imprudently' , 'do not disregard' , 'broad knowledge' , 'emergency treatment skill' , 'dependability' ,'consolation' giving a sense of security' , 'a self sacrificing spirit' , 'a sense of responsibility' 'hard - working', 'enough disposition of nursing staff (each 9.5%), 'improve patient's pride' and the rest attributes exhibited 4.7%, respectively. 2. The attributes that were identified in patients' data only were 8 categories, 'service sprit' (58.3 %) 'expert knowledge' , 'good answer a question' (each 25.0%), 'hard working' (16.7%), 'a warm character', 'professional attainments', 'do without reserve', 'satisfaction' (each 8.3%), 3. The attributes were identified to families' data only were 31 categories, 'speaking warmly' , 'direct nursing care', 'adress kindly', 'patientcentered nursing care', 'showing an example' (each 33.3%). 'do not imprudently' , 'do not disregard' , 'consolation', 'giving a sense of security', 'broad knowledge' , 'emergency treatment skill', 'dependability' ,'a self - sacrificing spirit', 'a sense of responsibility' (each 22.2%), 'improve patient's pride' , 'without discrimination' , 'show kindness' , 'individual nursing care', 'being with patient' , 'helping' , 'accuracy' , 'without any mistake' , 'love' , 'self - confidence', 'self possession', 'a self - denying spirit' , 'a sense of duty' , 'tighten discipline' , 'disposed room with similar patient to diagnosis', 'compensatory relationship between me dical team' , 'role of connection' (each 11.1 %). 4. The attributes of quality nursing care were integrated into 11 categories that they were 'patientcentered nursing care' (25.1%), 'expertise' (22.1%), 'caring'(18.1%), 'kindness'(11.1%L 'nurse attainments(10.1%), 'sincerity' (7.5%), 'good environment' (2.0%), 'effective organizational management', 'coordination', 'enough nursing staff' ( each 1.0%), 'satisfaction' (0.5%) were showed in the order of the highest rate. 5. The concept of quality nursing care were defined as 'give a satisfaction to patients by patientcentered care based on professional skill and caring with kindness and sincerity'. The description of the meaning of quality nursing care provided by this research participants, patients and families can provide important information for quality nursing care management, medical marketing, education and researches of this field. On the basis of the above findings the following recommendations are made: to suggest to utilize this results for patient care in practice setting, development of quality assessment tool in nursing care, repeat study by the same subjects and method, and to a comparative study by the same method to nurse.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.4
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• pp.69-85
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• 2014

Carbon stocks of NFI plots can be accurately estimated using field survey information. However, an accurate estimation of carbon stocks in other unsurveyed sites is very difficult. In order to fill this gap, various spatial information can be used as an ancillary data. In South Korea, there is the 1:5,000 forest type map that was produced by digital air-photo interpretation and field survey. Because this map contains very detailed forest information, it can be used as the high-quality spatial data for estimating carbon stocks. In this study, we compared three upscaling methods based on the 1:5,000 forest type map and 5th national forest inventory data. Map algebra(method 1), RK(Regression Kriging)(method 2), and GWR(Geographically Weighted Regression)(method 3) were applied to estimate forest carbon stock in Chungcheong-nam Do and Daejeon metropolitan city. The range of carbon stocks from method 2(1.39~138.80 tonC/ha) and method 3(1.28~149.98 tonC/ha) were more similar to that of previous method(1.56~156.40 tonC/ha) than that of method 1(0.00~93.37 tonC/ha). This result shows that RK and GWR considering spatial autocorrelation can show spatial heterogeneity of carbon stocks. We carried out paired t-test for carbon stock data using 186 sample points to assess estimation accuracy. As a result, the average carbon stocks of method 2 and field survey method were not significantly different at p=0.05 using paired t-test. And the result of method 2 showed the lowest RMSE. Therefore regression kriging method is useful to consider spatial variations of carbon stocks distribution in rugged terrain and complex forest stand.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.2
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• pp.1-20
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• 2020

The purpose of this study was to analyze the distribution characteristics of spatial and temporal PM_2.5 in urban areas of Changwon-si, and to identify the causes of PM_2.5 by comparing the characteristics of land-use, and to suggest the direction of reduction measures. As the basic data, the every hour average from September 2017 to August 2018 of Airpro data, which has measurement points in kindergartens, elementary schools, and some middle and high schools in Changwon-si was used. Also, by using IDW method among spatial interpolation methods of GIS, monthly and time-slot distribution maps were constructed, and based on this, spatial and temporal PM_2.5 distribution characteristics were confirmed. First, to verify the accuracy of the Airpro data, the correlation with AirKorea data managed by the Ministry of Environment was confirmed. As a result of the analysis, R² was 0.75~0.86, showing a very high correlation and the data was judged that it was suitable for the study. In the monthly analysis, January was the highest year, and August was the lowest. As a result of analysis by time-slot, The clock-in time at 06-09 was the highest, and the activity time at 09-18 was the lowest. By administrative district, Sangnam-dong, Happo-dong, and Myeonggok-dong were the most severe regions of PM_2.5 and Hoeseong-dong was the lowest. As a result of analyzing the land-use characteristics by administrative area, it was confirmed that the ratio of traffic area and commercial area is high in the serious area of PM_2.5. In conclusion, the results of this study will be used as basic data to grasp the characteristics of PM_2.5 distribution in Changwon-si. Also, it is thought that the severe regions and the direction of establishing reduction measures derived from this study can be used to prepare more effective policies than before.