• Journal of the Korean Geotechnical Society
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• v.26 no.5
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• pp.49-55
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• 2010

The large scale rock falling had occurred on 22nd February, 2007 in the Cheongbuldong valley area of Seoraksan National Park, and the visiting pass had been closed for a while. Similar cases of rock falling have occurred in the latest years according to a great variety of crack, joint, weathering of solid rock and surface water caused by a recent climatic change in the Seoraksan National Park. In this study, rock falling energy was estimated and the movement of rockslide was analysed based on detailed investigation on large scale rockslides occurring at the spot 80 m high from the bottom of the valley. From analysing results, the effective management method for rock falling was proposed. The method could minimized the dangerous factors with no change of natural environment of the National Park.

• Journal of the Korean Society of Radiology
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• v.5 no.4
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• pp.189-194
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• 2011

This study used magnetic resonance diffusion tensor imaging (DTI) to quantitatively analyze the neural fiber tractography according to the age of normal corpus callosum and to evaluate of usefulness. The research was intended for the applicants of 60 persons that was in a good state of health with not brain or other disease. The test parameters were TR: 6650 ms, TE: 66 ms, FA: $90^{\circ}$, NEX: 2, thickness: 2 mm, no gap, FOV: 220 mm, b-value: $800s/mm^2$, sense factor: 2, acquisition matrix size: $2{\times}2{\times}2mm^3$, and the test time was 3 minutes 46 seconds. The evaluation method was constructed the color-cored FA map include to the skull vertex from the skull base in scan range. We set up the five ROI of corpus callosum of genu, anterior-mid body, posterior-mid body, isthmus, and splenium, tracking, respectively, and to quantitatively measured the length of neural fiber. As a result, the length of neural fiber, for the corpus callosum of genu was 20's: $61.8{\pm}6.8$, 30's: $63.9{\pm}3.8$, 40's: $65.5{\pm}6.4$, 50's: $57.8{\pm}6.0$, 60's: $58.9{\pm}4.5$, more than 70's: $54.1{\pm}8.1mm$, for the anterior-mid body was 20's: $54.8{\pm}8.8$, 30's: $58.5{\pm}7.9$, 40's: $54.8{\pm}7.8$, 50's: $56.1{\pm}10.2$, 60's: $48.5{\pm}6.2$, more than 70's: $48.6{\pm}8.3mm$, for the posterior-mid body was 20's: $72.7{\pm}9.1$, 30's: $61.6{\pm}9.1$, 40's: $60.9{\pm}10.5$, 50's: $61.4{\pm}11.7$, 60's: $54.9{\pm}10.0$, more than 70's: $53.1{\pm}10.5mm$, for the isthmus was 20's: $71.5{\pm}17.4$, 30's: $74.1{\pm}14.9$, 40's: $73.6{\pm}14.2$, 50's: $66.3{\pm}12.9$, 60's: $56.5{\pm}11.2$, more than 70's: $56.8{\pm}11.3mm$, and for the splenium was 20's: $82.6{\pm}6.8$, 30's: $86.9{\pm}6.4$, 40's: $83.1{\pm}7.1$, 50's: $81.5{\pm}7.4$, 60's: $78.6{\pm}6.0$, more than 70's: $80.55{\pm}8.6mm$. The length of neural fiber for normal corpus callosum were statistically significant in the genu(P=0.001), posterior-mid body(P=0.009), and istumus(P=0.012) of corpus callosum. In order of age, the length of neural fiber increased from 30s to 40s, as one grows older tended to decrease. For this reason, the nerve cells of brain could be confirmed through the neural fiber tractography to progress actively in middle age.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.11-25
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• 2014

The purpose of this study is analyzing the network of the National Assembly based on the bill data in 18th, 19th National Assembly lawmakers submit to Committees. By using bipartite projection we find out a strong committee and understand the relationship of committees. We focused on bills that ten or more of the legislators propose and compare between the first opposition party and the ruling party, which accounts for more than 80% of the overall structure of the National Assembly. We point out an influential legislator and committee in the network. This result presents which committees and lawmakers have a significant effect on process of legislation. This work gives a reasonable source as qualified to judge whether the committee and legislators group enact positively or not.

• Journal of the Korean Society of Radiology
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• v.11 no.5
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• pp.413-421
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• 2017

Mammography, the basic test for finding and treating increased breast cancer, gives the anxiety of cancer and radiation exposure to most women. In addition, it gave very severe compression pain, so we studied the degree of pain and tried to reduce the pain. The purpose of this study is to compare and analyze the modified imaging technique and the basic imaging technique based on clinical experience, respectively. The subjects of this study were 160 women from 30 to 60 years old who visited to Seoul Boramae Hospital operated by Seoul National University Hospital from February to March 2017 for breast screening. Modified 80 persons and 80 persons were divided into two groups, and each group was asked to fill out questionnaires sequentially without knowing the subjects. The first method is a modified method in which an automatic pedal is divided into four or more presses, a manual pressure is used together, and an attitude is described in detail. Secondly, we used only the automatic pedal compression method and press it within 1-3 times. In the mean of the pain distribution, the experimental group (modified method) was 2.49 and the control group (basic method) had an average of 4.86, which showed 48.8% less pain. In this modified method, the pain scores of the experimental group were lower than those of the control group, and the degree of the pain was statistically significant.

• Journal of the Korean Society of Radiology
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• v.6 no.5
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• pp.389-394
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• 2012

In this study, based on IEC 60601-2-54 standard load conditions presented in the limited interval over the air kerma at the absolute linearity closely evaluated by measuring the X-ray results were as follows: 10 units targeted all Diagnostic X-ray generating device (DR) presented in the IEC 60601-2-54 standard linearity of air kerma emerged as inappropriate, the general evaluation of the dose linearity from four in the top 50% and 80 kVp % of the two measurement series were as irrelevant all the rest from six of the top tube voltage of 50% and 80% of the two measurement series, appeared in all suitable. Presented in IEC 60601-2-54 standard dose linearity testing and conventional linearity tests showed many differences. IEC 60601-2-54 standard linearity in the proposed international standards of air kerma is the recommendation of the existing dose linearity considerably more feasible, and to quantify the amount of radiation as the standard suggested by the standard IEC 60601-2-54 air kerma of a diagnostic X-ray imaging device linearity performance management is considered key elements in the critical appraisal.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.149-153
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• 2001

Three-dimensional thermoluminescence(TL) spectra of LiF: Mg, Cu, Na, Si TL material based on temperature, wavelength and intensity were measured and analyzed. The glow curves were obtained by integration of luminescence intensity for wavelength at each temperature, and various trapping parameters related to the trap formation were determined by analyzing these curves. Computerized glow curve deconvolution(CGCD) method which based on general order kinetics(GOK) model were used for the glow curve analysis. The glow curves of LiF:Mg, Cu, Na, Si TL material were deconvoluted to six isolated glow curves which have peak temperature at 333 K, 374 K, 426 K, 466 K, 483 K and 516 K, respectively. The 466 K main glow peak had an activation energy of 2.06 eV and a kinetic order of 1.05. This TL material was also found to have three recombination centers, 1.80 eV, 2.88 eV and 3.27 eV by TL spectra analysis based on Franck-Condon model. It showed that 2.88 eV is the dominant center, followed by 3.27 eV level, and 1.80 eV center is ascertained as emission center of this material even though its very weak emission intensity.

• Journal of Soil and Groundwater Environment
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• v.11 no.4
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• pp.48-56
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• 2006

Using a continuous injection tracer test at a multi-soil layer deposit, the difference of hydrodynamic dispersions in unsaturated and saturated zones were analyzed through breakthrough curves of Rhodamine WT, linear regression of concentration versus time, concentration variation rates versus time, and concentration ratio according to the distance from injection well. As a result of continuous injection tracer test, the difference of the maximum concentrations of Rhodamine WT in unsaturated and saturated zones were 13-15 times after 160 hours, and the increased rate of concentration versus time in unsaturated zone was about 10 times higher than in saturated zone. The fluctuation of Rhodamine WT breakthrough curve and concentration variation rate with time in saturated zone were larger than in unsaturated zone. Rhodamine WT concentration ratio with the distance from the injection well in saturation zone was linearly decreased faster than in unsaturated zone, and the elapsed time necessary for the concentration ratio less than 2 was longer in saturation zone. The differences resulted from the lower concentration and slower hydrodynamic dispersion of Rhodamine WT at the saturation zone of the multi-soil layer deposit, in which groundwater flow significantly flow and aquifer materials have high hydraulic heterogeneity. Effective porosity, longitudinal and transverse dispersivities were estimated $10.19{\sim}10.50%,\;0.80{\sim}1.98m$ and $0.02{\sim}0.04m$, respectively. The field longitudinal dispersivity is over 12 times larger than the laboratory longitudinal dispersivity by the scale-dependent effect.

• Journal of Soil and Groundwater Environment
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• v.7 no.3
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• pp.33-44
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• 2002

A field technique for assessing the transmissive fractures in an aquifer was applied to a fractured rock formation in Youngchun area Korea. Geological mapping and detailed acoustic borehole teleview(BHTV) logging were performed to obtain information about the fractures. The study area consists predominantly of two types of fractures. The fracture sets of low angle partings such as bedding and sheeting plains have strike N70-80$^{\circ}$W, 25$^{\circ}$-30$^{\circ}$SW and N3S$^{\circ}$W, 12$^{\circ}$NE, respectively. In areas of high fractures, on the other hand, the major fracture sets show strike N80$^{\circ}$W and dip 70$^{\circ}$-85$^{\circ}$SW, N10$^{\circ}$E.85$^{\circ}$SE in sedimentry rocks, N40-50$^{\circ}$E.85$^{\circ}$SE/85$^{\circ}$NE, N70$^{\circ}$E.80$^{\circ}$SE, and N7$^{\circ}$-75$^{\circ}$W.80$^{\circ}$SW in granites and volcanic rocks. Injection tests have been performed to identify discrete production zones and quantify the vertical distribution of hydraulic conductivity. The calculated hydraulic conductivities range from 3.363E-10 to 2.731E-6, showing that the difference between maximum and minimum value is four order of magnitude. Dominant section in hydraulic conductivity is extensively fractured. Geophysical logging was carried out to clarify characterization of the distribution of fracture zones. Transmissive fractures were evaluated through the comparison of the results obtained by each method. The temperature logs appeared to be a good indicator that can distinguish a high transmissive fractures from a common fractures in hydraulic conductivity. In numerous cases, evidence of fluid movement was amplified in the temperature gradient log. The fracture sets of N70-80$^{\circ}$W.60-85$^{\circ}$NE/SW N75-80$^{\circ}$W.25-30$^{\circ}$SW, N50-64$^{\circ}$W.60-85$^{\circ}$NE, N35-45$^{\circ}$E.65-75$^{\circ}$SE, and N65-72$^{\circ}$E.80$^{\circ}$SE/60$^{\circ}$NW were idenfied as a distinct transmissive fractures through the results of each tests.

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.264-272
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• 2007

Runoff of non-point pollutants has affected bad influence to water quality of river as reaching within short time. For this reason, reducing them prior to reaching aquatic systems or treating them after collection from discharge process of pollutants are desirable for efficient treatment of pollutants. This study was carried out to develop an ecotechnological method to prevent further aggravation of water quality by non-point source through vegetation filter strips. This study has placed a focus on improving infiltration capacity of soil for the optimum condition of vegetation filter strips. Therefore, we used titled soil filter strips instead of vegetation filter strips in this study. The three types of soil tilter strips were used in a bench scale experiment before applying to the field. The reduction efficiency of pollutants in soil filter strips (SS $84.5{\sim}92.5%$, BOD $67.9{\sim}80.6%$, T-N $43.4{\sim}76.6%$, T-P $40.6{\sim}87.4%$, Cu $28.3{\sim}48.1%$ Fe $92.1{\sim}97.7%$, Pb $81.4{\sim}97.3%$) was much higher than that of the controled group. And non-point pollutants reduction efficiency by soil filter strip's forms was estimated to be distinguishing in order of bio material, mixture of sand and gravel and lastly the whole gravel. In the event, the whole reduction efficiency of pollutants on the soil filter strips disclosed good results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.245-251
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• 2018

This study was conducted to investigate the status of the installation, maintenance and management of automatic external defibrillators (AEDs) in all mandatory institutions and buildings of the providence to be equipped with AEDs. The study was conducted from November 20, 2017 to December 20, 2017, during which time 169 AED units were surveyed. The collected data was analyzed by frequency analysis and the percentage was determined using the SPSS/WIN 20.0 program. A total of 168 units (99.41%) of AEDs were installed inside. Additionally, 47 units (27.80%) were available 24 hours a day, and 44 units (26.00%) were available outside business hours of the institution. Moreover, 87 units (51.43%) of the responsible managers received rescue and first aid training. Evaluation of the management status of the AEDs revealed two (1.20%) that had problems with their battery state of charge battery charge and seven (4.10%) for which the AED pads were past the expiration date. A management system for the manager of AEDs should be established and a regular training program for their systematic maintenance should be developed and applied. It is also suggested that awareness of the necessity of continuous management be raised through reinforcement of laws and legal system reorganization.