• 노동경제논집
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• 제41권4호
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• pp.1-30
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• 2018

1995년 소득세제 개편으로 인해 1996년 귀속분 소득부터 적용되는 한계세율, 과세표준구간, 그리고 각종 공제제도가 조정되면서 누진도가 크게 낮아졌다. 본 연구에서는 소득세제 개편으로 인한 세후 임금률 변화가 노동공급에 미친 인과효과를 분석하기 위해 이중차분 분석을 시행하였다. 자료로는 1989~2000년 "경제활동인구조사"와 1992~97년 "대우패널데이터"를 이용하였다. 25~55세 남성 가구주 임금근로자를 대상으로 분석한 결과 세제개편의 영향을 받은 근로자의 연간 근로시간이 1.5% 정도 통계적으로 유의하게 증가한 것으로 나타났다.

• 응용통계연구
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• 제36권5호
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• pp.415-445
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• 2023

생존 자료에서 Hade 등 (2020) 은 시간-의존 교란 변수가 환자의 처치 시점에 영향을 미칠 때, 해당 효과를 보정하여 treatment delay effect를 올바르게 추정하기 위해 성향 점수 매칭 방법을 이용하였다. 이 때, treatment delay effect란 환자가 관심 있는 지연 시점만큼 늦게 처치를 받는 경우 제 때 받는 경우에 비해 사건 발생 위험에 미치는 영향을 의미한다. 본 연구에서는 또 다른 성향 점수 기반 모형인 Cox-MSM 모형 또한 해당 효과를 올바르게 추정할 수 있는지 모의 실험을 통해 확인 및 기존 매칭 모형과 비교하였다. 모의실험 결과, 세 가지 모형 모두 다양한 시나리오 내에서 treatment delay effect를 올바르게 추정함을 확인하였다. 특히 모든 시나리오 내에서 Cox-MSM의 제곱근평균제곱오차의 값이 가장 낮았으며, restricted Cox matching 모형에서 가장 큰 값을 가지는 것으로 나타났다. 결론적으로, 성향 점수에 기반하나 매칭이 아닌 방법 또한 treatment delay effect 적용이 가능하다는 결과를 제공한다. 추후 G-formula과 같이 성향 점수 기반이 아닌 모형에서도 적용이 가능한지에 대한 상세 연구가 필요하다고 사료된다.

• 한국수소및신에너지학회논문집
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• 제22권3호
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• pp.292-298
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• 2011

This study examines the effects of the ambient temperature (AT), methanol feeding temperature (MFT), methanol concentration (MC) and methanol flow rate (MFR) on the performance and cell temperature (CT) of a 5-stacked direct methanol fuel cell (DMFC). The AT, MFT, MC, and MFR are varied from $-10^{\circ}C$ to $+40^{\circ}C$, $50^{\circ}C$ to $90^{\circ}C$, 0.5M to 3.0M and 11.7 mL $min^{-1}$ to 46.8 mL $min^{-1}$, respectively. The performance of the DMFC under various operating conditions is analyzed from the I-V polarization curve, and the methanol crossover is estimated by gas chromatography (GC). The performance of the DMFC improves significantly with increasing AT. The open circuit voltage (OCV) decreases with increasing MC due to the enhanced likelihood of methanol crossover. The cell performance is improved significantly when the MFR is increased from 11.7 mL $min^{-1}$ to 28.08 mL $min^{-1}$. The change in cell performance is marginal with further increases in MFR. The CT increases significantly with increasing AT. The effect of the MFT and MFR is moderate, and the effect of MC is marginal on the CT of the DMFC.

• 복식
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• 제30권
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• pp.59-68
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• 1996

As a society is becoming more and more complicated people living in modern times are experiencing more stresses for various reasons. Some past research results proved the role of clothing in reducing the stresses. The purpose of this study is to investigate how the preference of the mini-style which is recently most fashionable styles is related to the psychological factors such as stress and body satisfaction. Measure Instrument were Nolmes and Masuda(1973)'s SRRS(Social Readjustment Rating Scal) Secord and Jourard(1953)' Body Cathexis Scale and mini-style preference scale by author Survey questionnaires were distributed to two hundred seventy adult women living in Seoul area during may 25 1992. through June 8. 1992. The age range of the subjects was from 30 to 49 The final number of subjects in-cluded in the statistical analysis was 244. The result and conclusions are as follows: 1. Significant difference was existed in mini-style preference between high and low body satisfaction groups. Mini-style was pre-ferred by high body satisfaction group than low body satisfaction group. 2, Significant difference was existed in mini-style preference between high and low stress groups. Mini-style was preferred by low stress group than high stress group. 3. Regarding demographic characteristics unmarried 2 year college graduates with low family income in their early 30's pref. mini-style. 4. There was a marginal interaction effect of demographic characteristics on the relation-ship between mini-style preference and body satisfaction. The higher preference and body satisfaction. The higher preference for mini-style was found for the higher body satis-faction group mostly with the age range of 35 to 39 married 4 year college graduates as drop-puts and mid less income group. 5. There was a marginal interaction effect of demographic variables on the relatonship be-tween mini style preference and stress level The higher preference for mini-style was re-lated to the low stress level group mostly with age group of 35 to 44 high school graduates or lower and highest income group regardless of their marital status. In sum mini-style seems to be preferred by women who feel relatively less stress and are more satisfied with their bodies thus psycho-logically stable.

• 노동경제논집
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• 제43권1호
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• pp.1-34
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• 2020

급속하게 변화하는 경제환경에 개개인이 얼마만큼 유연하게 적응하는가는 매우 중요하며, 그 핵심적인 수단은 교육과 훈련이다. 따라서 직업 교육·훈련이 그 목적을 충분히 달성하고 있는지를 엄밀하게 측정하는 것은 매우 중요하다. 직업 교육·훈련이 실업자의 취업확률을 높이는지 여부, 즉 훈련의 효과를 엄밀하게 측정하기 위해서는 훈련 변수가 가지는 내생성을 통제해야 한다. 본 연구는 내생성 문제에 관한 기존 연구의 접근방법을 비판적으로 검토한 후, 다양한 계량모형을 적용하여 훈련이 취업에 미치는 효과를 살펴보았다. 분석 결과, 내일배움카드제의 훈련이 취업에 미치는 긍정적 효과는 확인할 수 없었다. 다만, 부정적인 효과가 유의미할 정도로 크지는 않은 것으로 나타났다. 또한, 훈련의 한계효과는 남성에 비해 여성에서, 저연령층에 비해 고연령층에서 부진한 모습을 보였으며, 연령에 따른 모습은 남성과 여성 간에 차이가 있는 것으로 나타났다. 이러한 결과에 대해서는 자료의 업데이트와 훈련과정에 대한 상세한 정보를 이용하여 보다 종합적이고 심층적으로 분석될 필요가 있다.

• 한국병원경영학회지
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• 제22권2호
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• pp.58-69
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• 2017

Recently, with the increase in the number of private health insurance subscribers, interest in overuse of the medical service is increasing. This study analyzed the impacts of private health insurance (PHI) on medical institution selection in outpatient service utilization among persons with arthritis. In order to control patients' health status, we extracted outpatient episodes with the same disease (KCD6, M13) from Korea Health Panel. The unit of analysis was an outpatient visit with arthritis in 2014 (n=23,363). In the light of insurance coverage, we redefined three type of private health insurance (ex, indemnity, fixed benefit, and non-insured) as a test variable and two type of medical institution (ex, hospital and physician visit) as a dependent variable. We conducted a probit regression analysis to identify the impacts of PHI on medical institution selection controlling for heteroscedasticity. The results of this study showed that the insured with indemnity were more likely to choose hospital departments than clinics (marginal effect=0.0475, p=0.000). The impact of participation of fixed benefit PHI was not as clear as that of indemnity type (marginal effect=0.0162, p=0.047). In conclusion, this study confirmed that PHI, particularly indemnity type has a significant impact on the selection of medical institutions. Healthcare policy makers should consider that PHI not only affects the overall quantitative increase in healthcare utilization, but also influences the selection of medical institutions.

• The Journal of Advanced Prosthodontics
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• 제4권1호
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• pp.18-23
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• 2012

PURPOSE. The purpose of this prospective study was to evaluate the effect of early loading on survival rate or clinical parameter of anodic oxidized implants during the 12- month postloading period. MATERIALS AND METHODS. Total 69 implants were placed in 42 patients. Anodic oxidized implants (GS II, Osstem Cor., Busan, Korea) placed on the posterior mandibles were divided into two groups, according to their prosthetic loading times: test group (2 to 6 weeks), and control group (3 to 4 months). The implant survival rates were determined during oneyear postloading period and analyzed by Kaplan-Meier method. The radiographic peri-implant bone loss and periodontal parameters were also evaluated and statistically analyzed by unpaired t-test. RESULTS. Total 69 implants were placed in 42 patients. The cumulative postloading implant survival rates were 88.89% in test group, compared to 100% in control group (P<.05). Periimplant marginal bone loss (T: $0.27{\pm}0.54$ mm, C: $0.40{\pm}0.55$ mm) and periodontal parameters showed no significant difference between the groups (P>.05). CONCLUSION. Within the limitation of the present study, implant survival was affected by early loading on the anodic oxidized implants placed on posterior mandibles during one-year follow-up. Early implant loading did not influence peri-implant marginal bone loss, and periodontal parameters.

• Journal of Periodontal and Implant Science
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• 제45권3호
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• pp.82-93
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• 2015

Purpose: This retrospective study evaluated the relationship between the timing of peri-implantitis diagnosis and marginal bone level after a 5-year follow-up of non-surgical peri-implantitis treatment. Methods: Thirty-three patients (69 implants) were given peri-implantitis diagnosis in 2008-2009 in Seoul National University Bundang Hospital. Among them, 31 implants from 16 patients were included in this study. They were treated non-surgically in this hospital, and came for regular maintenance visits for at least 5 years after peri-implantitis treatment. Radiographic marginal bone levels at each interval were measured and statistical analysis was performed. Results: Timing of peri-implantitis was one of the significant factors affecting initial bone loss and total bone loss not additional bone after peri-implantitis diagnosis. Patients with cardiovascular disease and diabetic mellitus were positively influenced on both initial bone loss and total bone loss. Patients who needed periodontal treatment after implant placement showed a negative effect on bone loss compared to those who needed periodontal treatment before implant placement during entire periods. Implant location also significantly influenced on amounts of bone loss. Mandibular implants showed less bone loss than maxillary implants. Among surgical factors, combined use of autogenous and xenogenic bone graft materials showed a negative effect on bone loss compared to autogenous bone graft materials. Use of membrane negatively affected on initial bone loss but positively on additional bone loss and total bone loss. Thread exposure showed positive effects on initial bone loss and total bone loss. Conclusions: Early peri-implantitis diagnosis led to early non-surgical intervention for peri-implantitis treatment, which resulted in the maintenance of the bone level as well as preservation of the implant.

• The Journal of Advanced Prosthodontics
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• 제15권3호
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• pp.145-154
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• 2023

PURPOSE. The objective of this study was to investigate how internal structures influence the overall and marginal accuracy of full arch preparations fabricated through additive manufacturing in different printing systems. MATERIALS AND METHODS. A full-arch preparation digital model was set up with three internal designs, including solid, hollow, and grid. These were printed using three different resin printers with nine models in each group. After scanning, each data was imported into the 3D data processing software together with the master cast, aligned and trimmed, and then put into the 3D data analysis software again to compare the overall and marginal deviation whose results are expressed using root mean square values and color maps. To evaluate the trueness of the resin model, the test data and reference data were compared, and the precision was evaluated by comparing the test data sets. Color maps were observed for qualitative analysis. Data were statistically analyzed by one-way analysis of variance and Bonferroni method was used for post hoc comparison (α = .05). RESULTS. The influence of different internal structures on the accuracy of 3D printed resin models varied significantly (P < .05). Solid and grid models showed better accuracy, while the hollow model exhibited poor accuracy. The color maps show that the resin models have a tendency to shrink inwards. CONCLUSION. The internal structure design influences the accuracy of the 3D printing model, and the effect varies in different printing systems. Irrespective of the kind of printing system, the printing accuracy of hollow model was observed to be worse than those of solid and grid models.

• The Journal of Advanced Prosthodontics
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• 제15권3호
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• pp.101-113
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• 2023

PURPOSE. This randomized controlled trial aimed to evaluate the effect of implants' two different diameters and cantilever lengths on the marginal bone loss and stability of mplants supporting maxillary prostheses. MATERIALS AND METHODS. Ninety-six implants were placed in sixteen completely edentulous maxillary ridges. Patients were randomly divided into two groups: Group A, implants were placed with a cantilever to anterior-posterior AP spread length (CL:AP) at a ratio of 1:3; Group B, implants were placed with a CL:AP at a ratio of 1:2. Patients were further divided into four sub-groups: Groups A1, A2, B1, and B2. Groups A1 and B1 received small diameter implants while Groups A2 and B2 received standard diameter implants. Bone height and stability measurements around each implant were performed at 0, 4, 8 and 24 months after definitive prostheses delivery. RESULTS. Statistical analysis of the mean implant stability and height values revealed an insignificant difference between Group A1 and Group A2 at all the different time intervals while significantly higher values in Group B1 in comparison with Group B2. Results also showed significantly higher values in Group A1 in comparison with Group B1 and an insignificant difference between Group A2 and Group B2 at all the different time intervals. CONCLUSION. It can be concluded that the use of small diameter implants placed with a CL:AP at a ratio of 1:3 provided predictable results and that the 1:2 CL:AP significantly induced more critical bone loss in the small diameter implants group, which can significantly reduce long term success and survival of implants