• Journal of Dental Rehabilitation and Applied Science
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• v.16 no.1
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• pp.13-25
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• 2000

Optimal Pressable Ceramic is one of the all-ceramic restorations with a shaded translucent pressed core and layering porcelains. The purpose of this study was to evaluate the marginal fidelity according to margin types and measurement sites, and to evaluate fracture strength according to margin types. Twenty seven OPC crowns made according to 3 types of cervical finishing lines were used in this study. Marginal gaps were measured before and after cementation. A Steromicroscope(SZ-ST(R), Olympus, Japan) was used to measure the space between the margin of OPC crown and the finishing line of metal model. Marginal gaps were measured at the labial, mesial, lingual and distal site, which were demonstrated in advance. Fracture strength testing was carried out using an Instron(Model M100EC, Mecmesin, England) at a cross head speed of 5 mm/min. All crowns were loaded until catastrophic failures occurred. The result were as follow: 1. In comparison according to variable margin before cementation, the marginal gap were increased in chamfer margin($47.50{\pm}18.39{\mu}m$), $120^{\circ}$shoulder margin ($55.21{\pm}14.4{\mu}m$) and $90^{\circ}$shoulder margin($71.18{\pm}13.30{\mu}m$) in ascending order, and there were significant differences between chamfer margin and $90^{\circ}$shoulder margin, $120^{\circ}$shoulder margin and between $120^{\circ}$shoulder margin and $90^{\circ}$shoulder margin respectively(p<0.05). 2. In comparison according to variable margin after cementation, the gap discrepancies were increased in chamfer margin($60.78{\pm}30.37{\mu}m$), $120^{\circ}$shoulder margin($66.67{\pm}11.18{\mu}m$) and $90^{\circ}$shoulder margin($85.78{\pm}17.23{\mu}m$) in ascending order, but there was significant difference only between chamfer margin and $90^{\circ}$shoulder margin(p<0.05). 3. Labio-lingual points showed a better marginal fidelity than that of proximal point(p<0.05). 4. Chamfer margin($48.76{\pm}8.45kgf$) showed higher fracture strength than $120^{\circ}$ shoulder margin($40.57{\pm}7.90kgf$) and $90^{\circ}$ shoulder margin(32.7.90kgf) (p<0.05), but there was significant difference only between chamfer margin and $90^{\circ}$ shoulder margin(p<0.05).

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.17
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• pp.93-125
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• 2002

This paper aims to find a reasonable solvency margin system in non-life insurance industry and also to evaluate the appropriateness of the current solvency margin regulation system in Korea. The current solvency margin system in Korea, based on EU's solvency margin model, was introduced during the 1997 financial crisis. The solvency requirement is not based on non-life insurer's risk, but simply on written premiums. The current solvency margin for general insurance, such as fire, marine, and automobile insurance, is determined by the greater between a premium-based amount and a claim-based amount, where the premium-based solvency margin is calculated by multiplying the net written premium for the preceding year by the premium based solvency margin ratio. Also, the amount of solvency margin for long term insurance is set at 4% of the policy reserve of the long term insurance. Still, there exist many differences between the current solvency margin regulation system in Korea and EU's model. This paper focuses on the rationality of the solvency margin regulation system, and compares the current system in Korea with EU's model and the RBC(Risk Based Capital) system in U.S. and Japan. Finally, this paper suggests a more specific and reasonable solvency margin system to be developed in Korea.

• Journal of Technologic Dentistry
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• v.6 no.1
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• pp.11-14
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• 1984

The auther performed this experimental study on cervical margin distortion in preheating method during soldering. 1. In soldering methods, the method using the furnace has less distortion than the method using open-flame and longer the bridge spon, the larger the distortions. 2. Table Ⅰ Showed that buccal margin, lingual margin, mesial margin and distal margin had respectively 0.01mm, 0.02mm, 0.03mm, 0.03mm closer adaptation in 3 unit bridge than in 5 unit bridges. 3. Table II showed that buccal margin, lingual margin, mesial margin and distal margin had respectively 0.06mm, 0.07mm, 0.11mm, 0.05mm closer adaptation in 3 unit bridge than in 5 unit bridges.

• The Korean Journal of Applied Statistics
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• v.17 no.1
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• pp.75-88
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• 2004

The Support Vector Machine(SVM) algorithm has paid attention on maximizing the shortest distance between sample points and discrimination hyperplane. This paper suggests the total margin algorithm which considers the distance between all data points and the separating hyperplane. The method extends existing support vector machine algorithm. In addition, this newly proposed method improves the generalization error bound. Numerical experiments show that the total margin algorithm provides good performance, comparing with the previous methods.

• East Asian Economic Review
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• v.17 no.3
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• pp.311-332
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• 2013

This paper examines the effect of initial margin requirements on long-run and short-run volatilities in the Japanese stock market using the Component GARCH model. Our empirical results show that when we do not divide the margin requirement into positive and negative changes, increasing margin requirement is effective for reducing long-run volatility, while not effective in short-run volatility. However, separating the positive and negative changes in margin requirements reveals the fact that the negative changes in margin requirements decrease long-run volatilities, while the higher margin requirements increase short-run volatilities in the Japanese stock market. This suggests that if the Japanese financial authorities intend to increase margin level to reduce volatility, unexpectedly, short-run volatility would be even higher.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.3
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• pp.445-457
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• 1997

Poor marginal fidelity resulting in a large marginal gap increases plaque accumulation, gingival inflammation and dental caries. The purpose of this study was to evaluate the marginal fit of three different cervical finishing methods of prepared teeth. A stereomicroscope was used to measure the space between the margin of restoration and the finishing line of prepared tooth. The results were statistically analyzed using the ANOVA and Multiple Range Test(Tukey's HSD). The results were as follows : 1. There were no significant differences concerning the types of tooth and positon (P>0.05), whereas the differences were statistically significant in case of cervical finishing methods (P<0.05). 2. There were statistically significant differences between before and after cementation (P<0.05). 3. In comparison according to variable margins after cementation, the gap discrepancies were increased in $130^{\circ}$ shoulder margin, chamfer margin and $90^{\circ}$ shoulder margin in ascending order, and there were significant differences between $90^{\circ}$ shoulder margin and chamfer, $130^{\circ}$ shoulder margin 4. In comparison according to variable margins, the gap discrepancies were increased in chamfer margin, $130^{\circ}$ shoulder margin and $90^{\circ}$ shoulder margin in ascending order, and there were significant differences between $90^{\circ}$ shoulder margin and chamfer, $130^{\circ}$ shoulder margin. 5. This study demonstrated a better marginal fit with all-ceramic crowns fabricated on chamfer and $130^{\circ}$ shoulder margin compared with $90^{\circ}$ shoulder margin.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.251-254
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• 2003

A voltage stability assessment consists of the contingency screening, voltage stability analysis, and counter measures. A widely used index for the voltage stability assessment of power system is the reactive power margin. It shows some factors of voluntariness as following the status of power system and load levels for the target analyzing area. Therefore, it has a demerit that the absolute amounts of reactive power margin is not to be applied by the quantized margin criterion. This paper selects a vulnerable area by assigning the voltage instability for the particular contingency for the selection of vulnerable area in the respect of the investigation of reactive power margin or VQVI as an index of V-Q margin sensitivity in order to overcome the demerit. This will be able to grasp the V-Q margin sensitivity for the target analyzing area by presenting the ratio of power margin between the margin before and after contingency as following the calculation of reactive power margin. The presented method is applied to the voltage stability assessment for the Metropolitan area of 2003 KEPCO summer peak system.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.54.3-54
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• 2001

This paper presents a controller design technique for standard 2nd-order system satisfying user-specified phase margin. A simple method is presented to meet stability margin for the 2nd-order system, which is important since the 2nd-order plant models are frequently encountered in the practical plant models such as actuators of the optical drive systems. Through the comparison of the specified stability margin and achieved stability margin, it is shown in the simple example that the proposed technique is useful in the initial design of control systems with stability margin specifications.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1086-1090
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• 2011

This paper presents a method to evaluate generation rescheduling priority using transient energy margin sensitivity for power system operation. A change in any of the functional parameters obviously causes a change in the energy margin. Especially the energy margin sensitivity is evaluated for change with respect to generation. For a given contingency, the energy margin is computed and the respective sensitivities are also computed. It is possible to rank the sensitivities and thereby determine the generators which will affect the energy margin most and hence affect the stability (instability) of the system. The sign of the sensitivity indicates the direction of change in generation for a given change in energy margin.

• KIEE International Transactions on Power Engineering
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• v.5A no.2
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• pp.152-158
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• 2005

This paper describes a reactive optimal power flow incorporating margin enhancement constraints. Margin sensitivity at a steady-state voltage instability point is calculated using invariant space parametric sensitivity, and it can provide valuable information for selection of effective control parameters. However, the weakest buses in neighboring regions have high margin sensitivities within a certain range. Hence, the control determination using only the sensitivity information might cause violation of operational limits of the base operating point, at which the control is applied to enhance voltage stability margin in the direction of parameter increase. This paper applies an interior point method (IPM) to solve the optimal power flow formulation with the margin enhancement constraints, and shunt capacitances are mainly considered as control variables. In addition, nonlinearity of margin enhancement with respect to control of shunt capacitance is considered for speed-up control determination in the numerical example using the IEEE 118-bus test system.