• 자원ㆍ환경경제연구
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• 제31권2호
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• pp.141-163
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• 2022

이 논문은 우리나라의 재생에너지 발전이 전력계통한계가격(System Marginal Price: SMP)에 미치는 영향을 실증적으로 분석한다. 2016~2020년 시간별 데이터를 사용하여 일일 평균, 피크 시간대, 피크 외 시간대의 SMP에 대해 ARX-GARCHX 모형으로 추정한 결과 총부하, 가스도입가격과 태양광 및 풍력 발전이 중요 결정요인으로 작용하고 있고, 특히 태양광 및 풍력 발전이 증가함에 따라 SMP는 하락하는 급전순위효과(merit order effect)가 존재하는 것을 확인하였다. 특히, 태양광 발전량의 1% 증가는 SMP 수준을 0.005%가량 하락시킬 뿐만 아니라 변동성을 증가시키는 것으로 나타났다. 이러한 결과는 재생에너지 발전이 증가함에 따라 SMP가 하락하여 기존 발전소의 수익성 감소와 재생에너지 투자 감소로 이어질 수 있음을 시사하고, 신재생에너지 보조금이 소매 부분 전기요금에 부담을 가중하더라도 계통한계가격이 낮아져서 이를 상쇄할 수 있음을 의미한다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제39권4호
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• pp.161-167
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• 2013

Objectives: The objective of this study is compare the rate of marginal bone resorption around hydroxyapatite-coated implants given different loading times in order to evaluate their stability. Materials and Methods: The study was conducted retrospectively for one year, targeting 41 patients whose treatment areas were the posterior maxilla and the mandible. Osstem TS III HA (Osstem Implant Co., Busan, Korea) and Zimmer TSV-HA (Zimmer Dental, Carlsbad, CA, USA), which employ the new hydroxyapatite coating technique, were used. The patients were divided into two groups - immediate and delayed loading - and the bone level at the time of loading commencement and after one year of loading was measured using periapical radiography. Differences between the groups were evaluated using Mann-Whitney (${\alpha}$=0.05). Results: For all patients as a single group, the survival rate of the implants was 100%, and the mean marginal bone loss was $0.26{\pm}0.59mm$. In comparison of the differences by loading, mean marginal bone loss of $0.32{\pm}0.69mm$ was recorded for the immediate loading group whereas the delayed loading group had mean marginal bone loss of $0.16{\pm}0.42mm$. However, the difference was not significant (P>0.05). Conclusion: Within the limited observation period of one year, predictable survival rates can be expected when using immediately loaded hydroxyapatite-coated implants.

• The Journal of Advanced Prosthodontics
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• 제8권4호
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• pp.313-320
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• 2016

PURPOSE. The aim of this study was to evaluate the clinical findings and patient satisfaction on implant overdenture designed with Locator implant attachment or Locator bar attachment in mandibular edentulous patients. MATERIALS AND METHODS. Implant survival rate, marginal bone loss, probing depth, peri-implant inflammation, bleeding, plaque, calculus, complications, and satisfaction were evaluated on sixteen patients who were treated with mandibular overdenture and have used it for at least 1 year (Locator implant attachment: n=8, Locator bar attachment: n=8). RESULTS. Marginal bone loss, probing depth, plaque index of the Locator bar attachment group were significantly lower than the Locator implant attachment group (P<.05). There was no significant difference on bleeding, peri-implant inflammation, and patient satisfaction between the two denture types (P>.05). The replacement of the attachment components was the most common complication in both groups. Although there was no correlation between marginal bone loss and plaque index, a significant correlation was found between marginal bone loss and probing depth. CONCLUSION. The Locator bar attachment group indicates lesser marginal bone loss and need for maintenance, as compared with the Locator implant attachment group. This may be due to the splinting effect among implants rather than the types of Locator attachment.

• The Journal of Advanced Prosthodontics
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• 제12권6호
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• pp.329-337
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• 2020

PURPOSE. To verify the influence of computer-aided design/computer-aided manufacturing (CAD/CAM) implant-supported prostheses manufactured with cobalt-chromium (Co-Cr) and zirconia (Zr), and whether ceramic application, spark erosion, and simulation of masticatory cycles modify biomechanical parameters (marginal fit, screw-loosening torque, and strain) on the implant-supported system. MATERIALS AND METHODS. Ten full-arch fixed frameworks were manufactured by a CAD/CAM milling system with Co-Cr and Zr (n=5/group). The marginal fit between the abutment and frameworks was measured as stated by single-screw test. Screw-loosening torque evaluated screw stability, and strain analysis was explored on the implant-supported system. All analyses were performed at 3 distinct times: after framework manufacturing; after ceramic application in both materials' frameworks; and after the spark erosion in Co-Cr frameworks. Afterward, stability analysis was re-evaluated after 106 mechanical cycles (2 Hz/150-N) for both materials. Statistical analyses were performed by Kruskal-Wallis and Dunn tests (α=.05). RESULTS. No difference between the two materials was found for marginal fit, screwloosening torque, and strain after framework manufacturing (P>.05). Ceramic application did not affect the variables (P>.05). Spark erosion optimized marginal fit and strain medians for Co-Cr frameworks (P<.05). Screw-loosening torque was significantly reduced by masticatory simulation (P<.05) regardless of the framework materials. CONCLUSION. Co-Cr and Zr frameworks presented similar biomechanical behavior. Ceramic application had no effect on the biomechanical behavior of either material. Spark erosion was an effective technique to improve Co-Cr biomechanical behavior on the implant-supported system. Screw-loosening torque was reduced for both materials after masticatory simulation.

• 한국산업융합학회 논문집
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• 제26권4_2호
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• pp.561-570
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• 2023

This study was to evaluate the effect of different rinsing times and methods on the accuracy of temporary prostheses fabricated by 3D printing method. Sixty temporary prostheses were fabricated with LCD types of 3D printer(Halot-Sky, Creality, Shenzhen, China) and divided into six groups (n = 10) based on rinsing times and methods. All specimens were rinsed with 99% isopropanol alcohol for 5 and 10 min using three methods-hand washed, ultrasonic cleaning, and automated washing. All specimens were polymerized for 3 minutes under the same conditions. The marginal and internal gaps of specimens were examined using a replica technique. The light-body silicone thickness was measured at 6 reference points(Absolute marginal discrepancy, Marginal, Chamfer, Axial, Angle, and Occlusal gap). All measurements were performed by a stereomicroscope. Reference point images were taken at 100× magnification and then measured using an image analysis program. Statistical analysis was performed using Two-way ANOVA, One-way ANOVA, and the Kruskal-Wallis test (p = .05). The marginal and internal gaps were statistically different according to the rinsing methods and rinsing times(p < .001). In the rinsing time, the temporary prosthesis rinsed for 5 minutes group showed higher accuracy than 10 minutes group. In the rinsing method, the hand washing group showed higher accuracy than the automated washing group.

• 대한치과기공학회지
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• 제44권1호
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• pp.1-7
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• 2022

Purpose: The purpose of this in vitro study is to evaluate the clinical acceptability of the marginal discrepancies and internal spacing of multi-layered zirconia prothesis by speed sintering. Methods: The two specimen types come from the same manufacturer but differ in the ingredients in layered zirconia and indication, that is anterior and posterior. The designs of both specimens were full contour crowns, and a total of 20 pieces were repeatedly fabricated, 10 for each group. The specimens were divided into two subgroups (n=10) and sintered with various total times (4 hours, 8 hours) at the maximum temperature (1,530℃). The gap between the two groups of multi-layered zirconia prostheses was measured using a silicone replica technique of 2D analysis method. The independent sample t-test was then used to compare and analyze the data obtained from the two groups (α=0.05). Results: The marginal and internal gap was superior in the 8-hour compared to the 4-hour group, and the results exhibited significant differences (p<0.05). All specimens showed that using the speed sintering schedule does not exceed the clinically permitted value of 120 ㎛, meaning zirconia prothesis using the speed sintering was adequate. Conclusion: The sintering condition is shown to affect the marginal and internal gaps of multi-layered zirconia restoration.

• 한국통신학회논문지
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• 제37권6B호
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• pp.453-463
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• 2012

본 접속료 차등의 효과는 선발 네트워크 사업자의 소매가격이 규제되지 않는 경우와 규제된 경우에 차이가 있다. 선발사업자의 소매가격이 규제되지 않는 경우엔 브랜드 충성도와 양 사업자간 한계비용의 상대적 크기가 소비자 후생효과를 결정한다. 즉, 브랜드 충성도와 후발사업자의 상대적 비용이 크면 접속료 차등은 소비자 후생을 증가시킨다. 그러나 선발사업자의 소매요금이 규제된 경우엔 브랜드 충성도와 비용이외에도 망간 가입자 대체성이 중요한 역할을 한다. 접속료 차등으로 인해 사회후생이 증가할 수 있기 위해서는 선발사업자의 브랜드 충성도가 높거나 대체성이 적거나 후발사업자의 한계비용이 커야 한다. 그 이외에는 접속료 차등화의 증가는 소비자 후생을 오히려 감소시킨다는 것을 알 수 있다.

• Journal of Nutrition and Health
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• 제25권5호
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• pp.397-403
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• 1992

This study was performed to investigate the effect of dietary magenesium on stress reactions in rats having abdominal surgery. Sixty three male rats of sprague-dawley strain were blocked into 3 groups : rats fed regular magnesium (0.05% Mg: control) rats receiving regular magnesium with surgery(Mg-adeq : S) Five weeks after feeding abdominal surgery was performed and randomly chosen 7 rats from each group were sacrificed on 1, 3 and 5 days after surgery. Te following were found ; 1) Rats fed marginal magnesium showed significantly elevated urinary urea nitrogen urinary potassium and plasma glucose compared controls only one day after abdominal surgery but not 3 days or 5 days after surgery 2) Rats fed adequate magnesium did not show any significant change in metabolic stress indicator after surgery. 3) Plasma free fatty acid and cortisol level were not different among groups. 4) Decreased plasma magnesium and potassium level were found in rats fed marginal magne-sium and sacrificed one day and three days after surgery.

• 아시안잔디학회지
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• 제10권1호
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• pp.13-20
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• 1996

This study was carried out to investigate the characteristics of spatial distributon patterns of users by each type of recreational activities at lawn areas in the parks. Study sites were lawn areas at Kyungju World and Seorabul Plaza in Bomun Resort Complex in Kyungju, Korea. Space types by each recreation activities are Repose Type, Sports Type, Play Type and Strolling Type. Main results are as follows ; 1. Sport Type activities were mainly distributed at the central areas of each lawn areas. 2.The density of Sports Type activities were affected by the form of lawn areas. For natural control of excess dynamic activities, Complex Form has more advantage in the distribution of dynamic activities. So, as the form of lawn areas in the parks, complex form is more desirable. 3.Repose Typo activities were distributed at marginal areas of lawns and surrounding woods. These, the static activities, were affected by Edge Effect in spatial distribution of activities. 4.Play Typo activities also were distributed at marginal areas of lawns. It was also affected by Edge Effect in spatial distribution. 5.Strolling Type activities were distributed evenly over all lawn areas.

• Communications for Statistical Applications and Methods
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• 제27권6호
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• pp.675-688
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• 2020

In survival analysis of observational data, the inverse probability weighting method and the Cox proportional hazards model are widely used when estimating the causal effects of multiple-valued treatment. In this paper, the two kinds of weights have been examined in the inverse probability weighting method. We explain the reason why the stabilized weight is more appropriate when an inverse probability weighting method using the generalized propensity score is applied. We also emphasize that a marginal hazard ratio and the conditional hazard ratio should be distinguished when defining the hazard ratio as a treatment effect under the Cox proportional hazards model. A simulation study based on real data is conducted to provide concrete numerical evidence.