• The Journal of Korean Society for Radiation Therapy
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• v.14 no.1
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• pp.175-186
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• 2002

The purpose of this study is directly measure and evaluate about absorbed dose change according to nominal energy and electron cone or medical accelerator on isodose curve, percentage depth dose, contaminated X-ray, inhomogeneous tissue, oblique surface and irradiation on intracavitary that electron beam with high energy distributed in tissue, and it settled standard data of hish energy electron beam treatment, and offer to exactly data for new dote distribution modeling study based on experimental resuls and theory. Electron beam with hish energy of $6{\sim}20$ MeV is used that generated from medical linear accelerator (Clinac 2100C/D, Varian) for the experiment, andwater phantom and Farmer chamber md Markus chamber und for absorbe d dose measurement of electron beam, and standard absorbed dose is calculated by standard measurements of International Atomic Energy Agency(IAEA) TRS 277. Dose analyzer (700i dose distribution analyzer, Wellhofer), film (X-OmatV, Kodak), external cone, intracavitary cone, cork, animal compact bone and air were used for don distribution measurement. As the results of absorbed dose ratio increased while irradiation field was increased, it appeared maximum at some irradiation field size and decreased though irradiation field size was more increased, and it decreased greatly while energy of electron beam was increased, and scattered dose on wall of electron cone was the cause. In percentage depth dose curve of electron beam, Effective depth dose(R80) for nominal energy of 6, 9, 12, 16 and 20 MeV are 1.85, 2.93, 4.07, 5.37 and 6.53 cm respectively, which seems to be one third of electron beam energy (MeV). Contaminated X-ray was generated from interaction between electron beam with high energy and material, and it was about $0.3{\sim}2.3\%$ of maximum dose and increased with increasing energy. Change of depth dose ratio of electron beam was compared with theory by Monte Carlo simulation, and calculation and measured value by Pencil beam model reciprocally, and percentage depth dose and measured value by Pencil beam were agreed almost, however, there were a little lack on build up area and error increased in pendulum and multi treatment since there was no contaminated X-ray part. Percentage depth dose calculated by Monte Carlo simulation appeared to be less from all part except maximum dose area from the curve. The change of percentage depth dose by inhomogeneous tissue, maximum range after penetration the 1 cm bone was moved 1 cm toward to surface then polystyrene phantom. In case of 1 cm and 2 cm cork, it was moved 0.5 cm and 1 cm toward to depth, respectively. In case of air, practical range was extended toward depth without energy loss. Irradiation on intracavitary is using straight and beveled type cones of 2.5, 3.0, 3.5 $cm{\phi}$, and maximum and effective $80\%$ dose depth increases while electron beam energy and size of electron cone increase. In case of contaminated X-ray, as the energy increase, straight type cones were more highly appeared then beveled type. The output factor of intracavitary small field electron cone was $15{\sim}86\%$ of standard external electron cone($15{\times}15cm^2$) and straight type was slightly higher then beveled type.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.396-406
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• 2018

The purpose of this study was to investigate the causal relationship between factors affecting the quality of life (QOL) of call center representatives by applying the PRECEDE model to structural equation modeling. The subjects of the survey were 695 consultants engaged in inbound work at four call centers in D metropolitan city. Data collection was conducted using structured, self-administered questionnaires from November 15th to December 5th, 2016. The results of this study show that the QOL of the reps was significantly negatively correlated with mental health and emotional labor but significantly positively correlated with work environment, self-efficacy, organizational support, and organizational commitment. The results of structural model analysis show that mental health had a negative influence on QOL, whereas work environment and self-efficacy had a positive influence. In addition, emotional labor had a negative effect on mental health, but organizational commitment and work environment had lowered emotional labor level. In addition, organizational support had enhanced employee self-efficacy and organizational commitment, and organizational commitment had mitigated emotional labor. Therefore, it is necessary to implement a health promotion program to improve the QOL of call center reps.

• Geophysics and Geophysical Exploration
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• v.12 no.2
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• pp.173-182
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• 2009

In April 2008, KIGAM carried out an ocean-bottom seismometer (OBS) survey in the central Ulleung Basin where strong bottom simulating reflectors (BSRs) were revealed from previous surveys and some gas-hydrate samples were retrieved by direct sampling. The purpose of this survey is to estimate the velocity structure near the BSR in the gas hydrate prospect area using wide-angle seismic data recorded on the ocean-bottom seismometers. Along with the OBS survey, a 2-D seismic survey was performed whereby stratigraphic and preliminary velocity information was obtained. Two methods were applied to wide-angle data for estimating P wave velocity; one is velocity analysis in the $\tau$-p domain and the other is seismic traveltime inversion. A 1-D interval velocity profile was obtained by the first method, which was refined to layered velocity structure by the latter method. A layer stripping method was adopted for modeling and inversion. All velocity profiles at each OBS site clearly show velocity reversal at BSR depths due to the presence of gas hydrates. In addition, we could confirm high velocity in the column/chimney structure.

• Journal of Korean Society of Transportation
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• v.14 no.2
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• pp.137-155
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• 1996

본 논문은 다이아몬드 인터체인지에서의 유고감지모형 개발을 위해 퍼지이론을 응용한 연구를 문서화 한 것이다. 지금까지의 교차로와 일반도로(고속도로가 아닌)에서의 유고감지에 관한 연구는 초기에 불과하다. 기존의 알고리즘들은 필요한 데이터 보존의 어 려움과 유고감지의 특성과 관련된 기술적 어려움을 효과적으로 극복하지 못하고 있다. 본 연구의 목적은 다이아몬드 인터체인지에서의 유고감지를 위한 새로운 모형을 개발하는데 있다. 이 연구를 통하여 개발된 유고감지 모형은 차량차단 유고(lane-blocking incidents) 를 감지하는데, 감지의 범위는 차량차단 유고의 경향이 교통 장황에 특정한 패턴을 형성 하고 그에 따른 신호제어전략의 조정이 요구될 때에 국한된다. 이 모형은 전통적인 통계 치를 이용한 유고감지감 고유의 문제를 해결하며, 보다 정확하고 신뢰성 있는 유고감지를 위해 다양한 교통변수를 이용하여 전체적인 유고의 경향을 포착한다. 또한 이 모형은 실 시간 교통대응 다이아몬드 인터체인지 신호제어 시스템 (real-time traffic adaptive diamond interchange control system)의 구성요소로써 사용되며, 그리고 더 큰 교차로 시스템에의 상용을 위하여 확장이 용역하도록 설계되었다. 본 연구를 통해 개발된 프로 토타입(prototype) 유고감지 모형은 실제의 다이아몬드 인터체인지에 적용되어, 감지율, 오보율, 평감지시간의 세 달로써 성능이 평가되었다. 모형의 성능평가 결과는 무적이었으 며, 퍼지이론은 유고감지에 효과적인 접근방법임을 확인할 수 있었다.투자의 타당성을 실증적으로 보여 주고 있다.산정 절차 정립에 엇갈림 알고리즘을 활용하는 방안을 제시하였다.자함수를 추정한 뒤 이를 이용해 업종, 기업규모, 상품유형별로 적합한 모델(Fixed Effects Model)을 결정하고, 각각에 해당하는 통계모형을 구축하였다. 이 결과 (1) 업종 및 기업규모별로 그룹간에 유의한 특성이 발견되었으며, (2) R&D 및 광고투자는 기업의 시장성과를 설명하는 중요한 변수이나, (3) R&D 투자의 경우는 광고에 비해 불확실성이 존재하는 것으로 나타났고, (4) 수리모형에서 도출된 한계원리가 통계모형에서도 유효한 것으로 드러났다.등을 토대로 한 10대 산업을 육성하기 위하여 과학기술부는 기술수요조사를 바탕으로 49개 주요기술을 도출하여, 과학기술 일류 국가 실현, 국민소득 2만불 달성이라는 국가적 슬로건을 내걸고 “차세대 성장동력” 창출을 위한 범정부차원의 기획과 연구비의 집중투자를 추진하고 있다.달성하기 위해서는 종합류류 전산망의 시급한 구축과 함께 화물차의 적재율을 높이고 공차율을 낮출 수 있는 운송체계의 수립이 필요한 것으로 판단된다. 그라나 이러한 화물전용차선의 효과는 단기적인 치유책일 수밖에 없기 때문에 물류유통 시설의 확충을 위한 사회간접자본의 구축을 서둘러 시행하여야 할 것이다.으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한

• Restorative Dentistry and Endodontics
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• v.31 no.6
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• pp.427-436
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• 2006

The objective of this study was to investigate the effects of various occlusal loads on the stress distribution of the buccal cervical region of a normal maxillary second premolar, using a three dimensional fnite element analysis (3D FEA). After 3D FE modeling of maxillary second premolar, a static load of 500N of three load cases was applied. Stress analysis was performed using ANSYS (Swanson Analysis Systems, Inc., Houston, USA). The maximum principal stresses and minimum principal stresses were sampled at thirteen nodal points in the buccal cervical enamel for each four horizontal planes, 1.0 mm above CEJ, 0.5 mm above CEJ, CEJ, 0.5 mm under CEJ. The results were as follows 1. The peak stress was seen at the cervical enamel surface of the mesiobuccal line angle area, asymmetrically. 2. The values of compressive stresses were within the range of the failure stress of enamel. But the values of tensile stresses exceeded the range of the failure stress of enamel. 3. The tensile stresses from the perpendicular load at the buccal incline of palatal cusp may be shown to be the primary etiological factors of the NCCLs.

• Journal of Radiation Protection and Research
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• v.42 no.1
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• pp.9-15
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• 2017

Background: The purpose of this study is to assign an appropriate density to virtual phantom for 2D diode array detector with different dose calculation algorithms to guarantee the accuracy of patient-specific QA. Materials and Methods: Ten VMAT plans with 6 MV photon beam and ten VMAT plans with 15 MV photon beam were selected retrospectively. The computed tomography (CT) images of MapCHECK2 with MapPHAN were acquired to design the virtual phantom images. For all plans, dose distributions were calculated for the virtual phantoms with four different materials by AAA and AXB algorithms. The four materials were polystyrene, 455 HU, Jursinic phantom, and PVC. Passing rates for several gamma criteria were calculated by comparing the measured dose distribution with calculated dose distributions of four materials. Results and Discussion: For validation of AXB modeling in clinic, the mean percentages of agreement in the cases of dose difference criteria of 1.0% and 2.0% for 6 MV were $97.2%{\pm}2.3%$, and $99.4%{\pm}1.1%$, respectively while those for 15 MV were $98.5%{\pm}0.85%$ and $99.8%{\pm}0.2%$, respectively. In the case of 2%/2 mm, all mean passing rates were more than 96.0% and 97.2% for 6 MV and 15 MV, respectively, regardless of the virtual phantoms of different materials and dose calculation algorithms. The passing rates in all criteria slightly increased for AXB as well as AAA when using 455 HU rather than polystyrene. Conclusion: The virtual phantom which had a 455 HU values showed high passing rates for all gamma criteria. To guarantee the accuracy of patent-specific VMAT QA, each institution should fine-tune the mass density or HU values of this device.

• 한국노년학
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• v.29 no.2
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• pp.579-591
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• 2009

The purpose of this study is what are the factors affecting decision making for selection of social welfare facility, esp., elderly care facility. The resident's selection for social welfare facility are relatively new terms in the Korean social work. To explore the factors, we employed an empirical study. The collected data was analyzed by using SEM(Structural equation modeling). As the results, the standardized regression coefficient of the hypothesis that the service quality will affect the service satisfaction is equal to 0.555(t=6.723, p<0.01) and the coefficient that the service satisfaction will affect the decision making is equal to 0.766. The absolute fitness of the SEM model shows χ² = 580.151(d.f.=317, p-value=0.000) and RMSEA=0.063, so that the model is absolutely fit. Since CFI=0.915, the model is comparatively fit. Conclusively speaking, the hypothesis that service quality affects to service satisfaction was supported. The hypothesis that service satisfaction affects to decision making was also supported. By accounting for the results of the analysis, this study verified the service quality leading to service satisfaction is an important factor for resident to select a residential facility.

• Korean Journal of Culture and Social Issue
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• v.19 no.4
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• pp.553-576
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• 2013

The purpose of this study was to investigate the impact of retirement stress, character strengths and marital dissatisfaction on depression. Additionally this study examined direct effects and indirect effects of character strengths and marital dissatisfaction. The participant group was composed of 197 retired men living in Daegu and Gyongsangbuk-do. The Retirement Stress Scale (RSS), Character Strengths Test (CST), Korean Marital Satisfaction Inventory (K-MSI), and Center for Epistemology Studies Depression scale (CES-D) were administered to participants. Structural Equation Modeling (SEM) with AMOS was used for the purpose of analysis. The results of the study were as follows. First, an increase in retirement stress was associated with higher levels of depression. Second, hierarchical regression analysis indicated that higher levels of optimism significantly predicted higher depression. Also hierarchical regression analysis indicated that lower levels of appreciation of beauty and excellence without optimism significantly predicted higher depression. Furthermore, increases in marital dissatisfaction were associated with higher levels of depression. Third, the constructed model including both direct effects and indirect effects appeared to fit better than alternative model in explaining relationships between retirement stress and depression. In other words, character strengths and marital dissatisfaction appeared to affect the depression levels of retired men directly and indirectly. To sum up, this study demonstrated that the factors which had an effect on depression in retired men, character strengths and harmonious marital relationships appeared to act as a buffer against depression in retired men. The current results might serve as basic data for psychological well-being programs for retired men. Finally, the limitations and implications of the current study were discussed.

• Korea Journal of Hospital Management
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• v.29 no.2
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• pp.57-79
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• 2024

Purpose: The present study identified the determinants in the development of intrapreneurial intention in small and medium-sized local hospitals. A careful literature review led to the development of a conceptual model which identified two types of employee competence-individual competence and managerial competence-to influence intrapreneurial orientation positively. It was hypothesized that intrapreneurial orientation predicts intrapreneurial intention and is mediated by intrapreneurial commitment. Methodology/Approach: The target population was chosen from two medical institutions of 'D' Hospital and 'E' Geriatric Hospital in Changwon City, South Korea. Samples were collected from 299 respondents who completed a structured questionnaire. Findings: The results from a structural equation modeling statistical analysis indicated that (1) individual competence and managerial competence positively and significantly predict intrapreneurial orientation, (2) intrapreneurial orientation positively and significantly influences intrapreneurial intention, (3) intrapreneurial commitment partially mediates the relation of intrapreneurial orientation to intrapreneurial intention, and (4) the mediation effect of intrapreneurial commitment was significant in the medical-personnel group, but not in the non-medical group. Practical Implications: Overall findings from the present work provide vital insights into understanding the preconditions for developing employee intrapreneurship in small and medium-sized local hospitals.

• Journal of Soil and Groundwater Environment
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• v.11 no.2
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• pp.45-55
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• 2006

A 2-D unconfined flow model is developed to analyze annual variations of groundwater level and bank filtration rate (BFR) for an experimental riverbank filtration site in Koryeong, Korea. Two types of boundary conditions are examined for the river boundary in the conceptual model: the static head condition that uses the average water level of the river and the dynamic cyclic condition that incorporates annual fluctuation of water level. Simulations show that the estimated BFR ranges $74.3{\sim}87.0%$ annually with the mean of 82.4% for the static head boundary condition and $52.7{\sim}98.1%$ with the mean of 78.5% for the dynamic cyclic condition. The results illustrate that the dynamic cyclic condition should be used for accurate evaluation of BFR. Simulations also show that increase of the distance between the river and the pumping wells slightly decreases BFR up to 4%, and thereby indicate that it is not a critical factor to be accounted for in designing BFR of the bank filtration system. A sensitivity analysis is performed to examine the effects of model parameters such as hydraulic conductivity and specific yield of the aquifer, recharge rate, and pumping rate. The results demonstrate that the average groundwater level and BFR are most sensitive to both the pumping rate and the recharge rate, while the water level of the pumping wells is sensitive to the hydraulic conductivity and the pumping rate.