Influence of B1-Inhomogeneity on Pharmacokinetic Modeling of Dynamic Contrast-Enhanced MRI: A Simulation Study

박범우,최병세,성유섭,우동철,심우현,김경원,최윤석,배상훈,서지연,조형준,김정곤 대한영상의학회 2017 Korean Journal of Radiology Vol.18 No.4

Objective: To simulate the B1-inhomogeneity-induced variation of pharmacokinetic parameters on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Materials and Methods: B1-inhomogeneity-induced flip angle (FA) variation was estimated in a phantom study. Monte Carlo simulation was performed to assess the FA-deviation-induced measurement error of the pre-contrast R1, contrast-enhancement ratio, Gd-concentration, and two-compartment pharmacokinetic parameters (Ktrans, ve, and vp). Results: B1-inhomogeneity resulted in -23–5% fluctuations (95% confidence interval [CI] of % error) of FA. The 95% CIs of FA-dependent % errors in the gray matter and blood were as follows: -16.7–61.8% and -16.7–61.8% for the pre-contrast R1, -1.0–0.3% and -5.2–1.3% for the contrast-enhancement ratio, and -14.2–58.1% and -14.1–57.8% for the Gd-concentration, respectively. These resulted in -43.1–48.4% error for Ktrans, -32.3–48.6% error for the ve, and -43.2–48.6% error for vp. The pre-contrast R1 was more vulnerable to FA error than the contrast-enhancement ratio, and was therefore a significant cause of the Gd-concentration error. For example, a -10% FA error led to a 23.6% deviation in the pre-contrast R1, -0.4% in the contrast-enhancement ratio, and 23.6% in the Gd-concentration. In a simulated condition with a 3% FA error in a target lesion and a -10% FA error in a feeding vessel, the % errors of the pharmacokinetic parameters were -23.7% for Ktrans, -23.7% for ve, and -23.7% for vp. Conclusion: Even a small degree of B1-inhomogeneity can cause a significant error in the measurement of pharmacokinetic parameters on DCE-MRI, while the vulnerability of the pre-contrast R1 calculations to FA deviations is a significant cause of the miscalculation.

GSCR과 이중 프라이머 적용법에 의한 심미의치 제작법

박범우,이해형 대한치과재료학회 2017 대한치과기재학회 학술대회 Vol.2017 No.11

2영역 동특성모델 기반 제어봉가 측정실험 결과분석

박범우,김경오,유한종 대한방사선방어학회 2022 대한방사선방어학회 학술발표회 논문요약집 Vol.2022 No.11

이중 primer를 사용한 의치상용 PMMA와 Gum-shade 복합레진의 전단결합강도

박범우,김시철,이해형 대한치과재료학회 2016 대한치과기재학회 학술대회 Vol.2016 No.-

의치상용 PMMA와 Gum-shade 복합레진의 전단결합강도 평가

박범우,임용운,이정환,이해형 대한치과재료학회 2015 대한치과재료학회지 Vol.42 No.S

외식고객의 고객시민행동과 고객불량행동이 서비스 종업원의 감정부조화와 직무소진에 미치는 영향

박범우(Beam-Woo Park) 한국산학기술학회 2020 한국산학기술학회논문지 Vol.21 No.3

본 연구는 외식 고객의 고객시민행동과 고객불량행동이 서비스 종업원의 감정부조화와 직무소진에 미치는 영향력을 밝히는데 목적을 갖는다. 이를 위해 서울지역 외식종업원 338명을 대상으로 실증조사 후 통계분석 프로그램을 통해 가설을 검정하였다. 전체적인 연구 결과 첫째, 고객시민행동이 감정부조화에 유의한 영향을 미치는 것으로 나타났다. 둘째, 고객시민행동이 직무소진에 미치는 영향은 유의하지 않은 것으로 나타났다. 셋째, 고객불량행동이 감정부조화에 유의한 영향을 미치는 것으로 나타났다. 넷째, 고객불량행동이 종업원의 직무소진에 유의한 영향을 미치는 것으로 나타났다. 다섯째, 종업원의 감정부조화가 직무소진에 유의한 영향을 미치는 것으로 나타났다. 이상의 결과를 종합해보면 외식고객의 고객시민행동이 서비스 접점에서 종업원의 감정부조화와 밀접한 영향을 미치는 요인으로 외식업에서의 고객시민행동과 고객불량행동의 중요성을 확인시켜 준 것으로 평가할 수 있다. 이는 고객의 불량행동이 종업원의 감정부조화와 직무소진에 유의한 영향을 나타내므로 서비스 담당 종업원의 무조건적인 감정 억제나 고객 우선 중심의 영업 전략을 추구할 시 서비스 품질 저하로 이어질 수 있음을 시사한다. 따라서 종업원과 고객의 우호적인 접점에서 긍정적인 상호작용을 통해 고객시민행동을 촉진시켜 충성스러운 서비스를 통해 공헌 행동을 유발할 수 있는 마케팅 측면에서의 전략적 시스템화가 요구된다. This study examines the effects of customer citizenship behavior and customer badness behavior on service employees" emotional dissonance and job burnout. To achieve this, a survey was empirically carried out to 338 foodservice employees. The overall findings were as follows. First, the customer citizenship behavior had a significant effect on the emotional dissonance of service employees. Second, the customer citizenship behavior had no significant effect on job burnout. Third, the customer badness behavior had a significant effect on the emotional dissonance. Fourth, the customer bad behavior had a significant effect on the job burnout. Fifth, the emotional dissonance had a significant effect on job burnout of service employees. These results confirmed the importance of customer citizenship behavior and customer badness behavior in the foodservice industry. This suggests that the customer badness behavior has a significant effect on the emotional dissonance and job burnout, leading to the deterioration of quality in the foodservice industry that pursues the unconditional suppression of service employees" emotion or customer-centered operating strategies. Therefore, strategic systemization is required in terms of promoting civil behavior on behalf of customers through positive interaction and induce contribution behavior through loyal service.

외식 창업가의 기업가 정신이 사회적 가치 창출과 지속경영에 미치는 영향

박범우(Park Beom woo) 대한관광경영학회 2017 觀光硏究 Vol.32 No.3

This study is intended to look into the effects of entrepreneurship on social value creation and sustainable management in the food service industry. To achieve this, a survey was empirically carried out to 202 food service entrepreneurs. The findings were as follows. First, entrepreneurship factors had no positive effect on sustainable management in the food service industry, and second, entrepreneurship factors had a positive effect on social value creation in the food service industry, and third, creation of social value had no positive effect on corporate value creation and sustainable management in the food service industry. The above-stated findings could confirm that their entrepreneurship is a promotion mechanism to have a direct effect on social value creation in the food service industry. However, rejecting it as it is not a positive variable in corporate sustainable management could mean that application variables depend on targets and environments. 본 연구는 외식 창업가의 기업가 정신이 사회적 가치창출과 지속경영에 미치는 영향력을 밝히는데 목적을 갖고 외식 창업자 219명을 대상으로 실증조사 하였는데 그 결과를 보면 다음과 같다. 첫째, 외식창업가의 기업가정신이 지속경영에 긍정적인 영향을 미치지 않는 것으로 나타나 기각되었으며 둘째, 외식창업가의 기업가정신이 사회적 가치창출에는 긍정적인 영향을 미치는 것으로 나타나 채택되었다. 셋째, 외식창업가의 사회적 가치 창출이 기업의 지속경영에 미치는 영향 또한 긍정적인 영향을 미치지 않는 것으로 나타나 기각되었다. 이 같은 결과는 외식창업가의 기업가정신이 사회적 가치창출에 직접적인 영향을 미쳐 촉진기제임을 확인시켜 준 것으로 볼 수 있으나 기업가 정신이 기업의 지속경영에는 긍정적인 변수로 작용 하지 않음으로 기각된 것은 대상과 환경에 따라 적용을 달리해야 함을 의미한 것으로 평가할 수 있다.

외식기업의 기업시민 행동과 윤리적 기업태도가 소비자의 윤리적 소비와 구매의도에 미치는 영향

박범우(Beam-Woo Park) 한국관광연구학회 2017 관광연구저널 Vol.31 No.6

홍국쌀 첨가 타락죽의 품질특성

김세한,박범우,김재환,Kim, Se-Han,Park, Beam-Woo,Kim, Jae-Hwan 한국식품영양학회 2015 韓國食品營養學會誌 Vol.28 No.2

This study encouraging the consumption of rice. The Tarakjuk in which red yeast rice was added showed the highest water content 78.31%. The viscosity of RRT20, which had the largest amount of red yeast rice, was the lowest for 4,125.50, and pH was the highest in RRT0 The sugar content of Tarakjuk with red yeast rice was the highest in RRT0 for. lightness (L) was lowest in RRT20 which had the largest amount of red yeast rice for, and its red and yellow lighteners were also the highest for respectively. storage at $4^{\circ}C$, no microorganism found for 0 to 1 day of storage but found in every group. The group showed the smallest of microorganism for $2.9{\times}10^2CFU/mL$. On the 7 day, microorganism also found 40% added showed the smallest of microorganism for $3.1{\times}10^4CFU/mL$. The color of the 20% added group, 6.74, was higher than that of the control group, 4.87, but the difference was not significant. The flavor was the in the 30% added group for 5.90, and taste was the in the 20% added group for 6.01 The control group showed the lowest preference for 4.91. The after taste was the in the 30% added group for 5.48. The viscosity of the 40% added group was higher for 5.39 than that of the control group for 5.06, no significant difference. The overall preference was rated highly, and the 20% added group showed the highest preference for 5.57.

Improved Diagnostic Accuracy of Alzheimer’s Disease by Combining Regional Cortical Thickness and Default Mode Network Functional Connectivity: Validated in the Alzheimer’s Disease Neuroimaging Initiative Set

박지은,박범우,김상준,김호성,최충곤,정승채,오주영,이재홍,노지훈,심우현,Alzheimer’s Disease Neuroimaging Initiative (ADNI) 대한영상의학회 2017 Korean Journal of Radiology Vol.18 No.6

Objective: To identify potential imaging biomarkers of Alzheimer’s disease by combining brain cortical thickness (CThk) and functional connectivity and to validate this model’s diagnostic accuracy in a validation set. Materials and Methods: Data from 98 subjects was retrospectively reviewed, including a study set (n = 63) and a validation set from the Alzheimer’s Disease Neuroimaging Initiative (n = 35). From each subject, data for CThk and functional connectivity of the default mode network was extracted from structural T1-weighted and resting-state functional magnetic resonance imaging. Cortical regions with significant differences between patients and healthy controls in the correlation of CThk and functional connectivity were identified in the study set. The diagnostic accuracy of functional connectivity measures combined with CThk in the identified regions was evaluated against that in the medial temporal lobes using the validation set and application of a support vector machine. Results: Group-wise differences in the correlation of CThk and default mode network functional connectivity were identified in the superior temporal (p < 0.001) and supramarginal gyrus (p = 0.007) of the left cerebral hemisphere. Default mode network functional connectivity combined with the CThk of those two regions were more accurate than that combined with the CThk of both medial temporal lobes (91.7% vs. 75%). Conclusion: Combining functional information with CThk of the superior temporal and supramarginal gyri in the left cerebral hemisphere improves diagnostic accuracy, making it a potential imaging biomarker for Alzheimer’s disease.