• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.669-675
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• 2018

This study aimed to investigate the difference of X-ray exposure by comparing and analyzing entrance surface dose and absorbed dose according to the frame change in coronary angiography using an X-ray machine. Moreover, appropriate frame selection measures for examination, including the effect of frame change on the image quality, were sought by measuring and analyzing the SNR and CNR of the image through image J. The study was conducted on 30 patients (19 males and 11 females) who underwent CAG at this hospital from June 2017 to October 2017. In regard to the patients, their age range was 49-82 years (mean of $65{\pm}9$ years), body weight was 45-91 kg (mean of $67{\pm}8.9kg$), height was 150-179cm (mean of $165.1{\pm}8.9kg$), and BMI was 19.5-30.5(mean of $24.5{\pm}2.9$). For the entrance surface dose and absorbed dose, air kerma value and DAP were obtained and analyzed retrospectively. The SNR and CNR were measured and analyzed through imageJ, and the result values were derived by applying the values to the formula. As for the statistical analyses, the correlations between the entrance surface dose and absorbed dose, and between the SNR and CNR were analyzed by using the SPSS statistical program. The relationship between the entrance surface dose and absorbed dose was not statistically significant for both 10 f/s and 15 f/s (p>0.05). In terms of the relationship between the SNR and CNR, the SNR ($3.374{\pm}2.1297$) and CNR ($0.234{\pm}0.2249$) in 10 f/s were $1.43{\pm}0.4861$ and $0.132{\pm}0.0555$ lower, respectively, than the SNR ($4.929{\pm}2.8532$) and CNR ($0.391{\pm}0.3025$) in 15 f/s, which were not statistically significant (p>0.05). In the correlation analysis, statistically significant results were obtained among the BMI, air kerma, and DAP; between air kerma and DAP; and between SNR and CNR (p<0.001, p<0.001). In conclusion, there was no significant difference between the entrance surface dose and absorbed dose even when the images were taken by changing the frame from 10 f/s to 15 f/s at the time of the coronary angiography. SNR and CNR increased at 15 f/s than at 10 f/s, but they were not statistically significant. Therefore, this study suggests that the concern of the patient and practitioner regarding image quality degradation, as well as the problem of X-ray exposure caused by imaging at 10 f/s and 15 f/s, may be reduced.

• The Korean Journal of Applied Statistics
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• v.18 no.1
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• pp.15-26
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• 2005

This study compares the difference of academic achievements for college students who entered a school with different selection criteria, and it was based on the entrance data for Hankuk University of Foreign Studies during 2000-2003. The results of this research can be used as an evidence or a supporting material for the future entrance policies or strategies in other universities.

• Journal of the Korea Furniture Society
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• v.23 no.4
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• pp.381-387
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• 2012

Utilization of underground floor is becoming the main issue of our society to maximize and diversify the potential of recent urban space. It has brought about the changes of underground floor. Recently there are lots of huge bookstores in these underground floor. Bleach, adhesive and ink used for manufacturing books pollute indoor air in bookstore. Therefore, the purpose of this study is to analyze indoor air quality in these large bookstores. Concentrations of carbon dioxide and formaldehyde in three large bookstores in Seoul were measured by presence and type of books and distance of main entrance which is well-ventilated. According to the data, space that places lots of volumes measured higher concentration of formaldehyde than that of non-existence books. Children's book section was measured more concentration of formaldehyde than other book section. Closer main entrance near outside, lower concentration of formaldehyde was measured. Concentration of carbon dioxide was affected by the number of people in bookstore.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.25.4-26
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• 2010

We present a three-mirror anastigmat(TMA) optical system for New Generation GOCI. In order to reduce the ghost optimized filter and baffle. By using carefully chosen antireflective coating and tilted filter angle, we fulfilled the design SNR requirement of 1500. We then designed a new entrance baffle and an internal baffle capable of producing the ghost ratio better than 0.01% of the nominal signal. The entrance baffle limits FOV to $0.75^{\circ}$ (E/W) $\times$ $0.60^{\circ}$ (S/N), and prevents the system from strong sun illumination, and the internal baffle prevents stray and scattered ray from entering into the telescope cavity. From these filter and baffle design, we confirmed that the instrument signal to noise ratio can be met with the current conceptual opto-mechanical design.

• Journal of Navigation and Port Research
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• v.41 no.5
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• pp.345-352
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• 2017

Recently, a new port reserves deep water depth for safe navigation and mooring, following the trend of larger ship building. Larger port facilities include long and huge breakwaters, and mainly adopt vertical type considering low construction cost. A vertical breakwater creates stem waves combining inclined incident waves and reflected waves, and this causes maneuvering difficulty to the passing vessels, and erosion of shoreline with additional damages to berthing facilities. Thus, in this study, the researchers have investigated the response of stem waves at the vertical breakwater near the entrance channel and applied numerical models, which are commonly used for the analysis of wave response at the harbor design. The basic equation composing models here adopted both the linear parabolic approximation adding the nonlinear dispersion relationship and nonlinear parabolic approximation adding a linear dispersion relationship. To analyze the applicability of both models, the research compared the numerical results with the existing hydraulic model results. The gap of serial breakwaters and aligned angles caused more complicated stem wave generation and secondary stem wave was found through the breakwater gap. Those analyzed results should be applied to ship handling simulation studies at the approaching channels, along with the mooring test.

• Journal of Labour Economics
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• v.44 no.1
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• pp.169-204
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• 2021

We empirically verified whether there are different educational investment behaviors according to university admissions, using the Korean Education and Employment Panel data. The results are as follows; the average annual private education cost and the average amount of time spent studying alone per week of rolling admission type were lower than those of regular admission type. Also, rolling admission applicants had longer leisure and sleeping hours, such as watching TV and using computers. These results show the possibility that the university admission system will change the educational investment behavior. Furthermore, there is a possibility to induce the human capital investment to be made efficiently.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1383-1392
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• 2007

The purpose of this study is to provide suitable outdoor spaces for Korean elderly, examining characteristics and types of existing outdoor spaces and presenting design guideline of outdoor space for elderly. To do this, this study examined previous research papers and scholastic writings, related to elderly housing, and analyzed twelve cases of elderly housing complex. Additionally evaluation of usage pattern and physical trace carried out on twelve cases. As a result, first, the study showed that outdoor spaces for elderly were classified 5 types; entrance area of housing complex, building entrance area, outdoor living area, in & outdoor neutral area, and parking lots. Outdoor living area is subdivided into residents' public space, green space, health & sports space and landscape space. Characteristics of outdoor space are deeply related to safety, amenity, recognition and efficiency. Second, types of outdoor space in elderly facilities are very limited in verity, just facilitating with rest space, sport space, and garden space. Third, from a standpoint of barrier-free-design, twelve cases are not carefully concerning about outdoor space for elderly.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.2
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• pp.234-245
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• 2012

This study aims to analyze the factors of the extra-curricula area in personal school performance record and propose the practical strategies for entrance examination affairs on this area. To address this goal, we have applied a SWOT analysis with related documents and research results. We found out five strengths: (S1) Link the students' experience to right people for the university, (S2) Quantitative Indicators, (S3) Qualitative Indicators, (S4) Link to other evaluation factors, and (S5) Analysis of Human Resource. The weakness included: (W1) Fairness, (W2) Reliability, (W3) Difficulties to set standards, (W4) Difficulties to set environments, and (W5) Lack of systemic experience of an evaluation. We also discovered five opportunities (O1) Recognition of public education, (O2) The need of national support, (O3) The importance of autonomy, (O4) Specialization, and (O5) Networks. Finally, threat factors consisted of: (T1) Frequent change of educational policy, (T2) Increasing of private education, (T3) Lack of information and preparation time, and (T4) The accuracy and reliability of personal school records. Based on these results, we suggested practical strategies with these four dimensions: S-O, W-O, S-T, and W-T.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.305-312
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• 2016

This study were compared with the direct measurement and indirect dose methods through various dose calculation in head and wrist. And, the modified equation was proposed considering equipment type, setting conditions, tube voltage, inherent filter, added filter and its accompanied back scatter factor. As a result, it decreased the error of the direct measurement than the existing dose calculation. Accordingly, diagnostic radiography patient dose comparison would become easier and radiogrphic exposure control and evaluation will become more efficient. The study findings are expected to be useful in patients' effective dose rate evaluation and dose reduction.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.3 no.1
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• pp.37-43
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• 2003

Current Internet system of the entrance exam information to the university that is depending on searching key to solve the overloaded problem in the network and DB server or other tools to support HTML edit, haven't satisfied user's wants by supplying uniformed searching system. So this thesis will establish EEIS(Entrance Examination Information System) to prevent database overload phenomena when many users request a great amount of data at the same time and improve the decrease of speed and overload problem in DB server. EEIS playa role of bridge between outside client and DB server by placing VVS(Virtual View Server) between web server and DB server. By that method this system give users several usefulness in convenience and variety by supplying realtime data searching function to user. EEIS also give inner system manager more efficiency and speed in control the management system by solving those problem. This system is design and implementation to satisfy user's desire and give them more convenience and bring up the confidence of university that adopt this system at the end.