• Proceedings of the Safety Management and Science Conference
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• 2008.11a
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• pp.505-515
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• 2008

This paper introduces six single and sequential acceptance sampling plans based on OC( Operating Characteristic) curve. Revised KS standards for acceptance sampling by attribute and by variable such as KSA 3102 : 1996, 3103 : 2005, KSA ISO 14560 : 2006, 8422 : 2001, 8423 : 2001 are presented.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.9-19
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• 2016

Accurate models of the characteristics of typical inverse-time overcurrent (OC) protective devices play an important role in the protective coordination schemes. This paper presents a novel approach to determine the OC protective device parameters. The approach is based on the Eigensystem Realization Algorithm which generates a state space model to fit the characteristics of OC protective devices. Instead of the conventional characteristic curves, the dynamic state space model gives a more exact fit of the OC protective device characteristics. This paper demonstrates the feasibility of decomposing the characteristic curve into smooth components and oscillation components. 19 characteristic curves from 13 typical and 6 non-typical OC protective devices are chosen for curve-fitting. The numbers of fitting components required are determined by the maximum absolute values of errors for the fitted equation. All fitted equations are replaced by a versatile equation for the characteristics of OC protective devices which represents the characteristic model of a novel flexible OC relay, which in turn may be applied to improve the OC coordination problems in the sub-transmission and distribution systems.

• Restorative Dentistry and Endodontics
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• v.45 no.3
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• pp.33.1-33.10
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• 2020

Objectives: This study was conducted to evaluate the effects of traditional and contracted endodontic cavity (TEC and CEC) preparation with the use of Reciproc Blue (RPC B) and One Curve (OC) single-file systems on the amount of apical debris extrusion in mandibular first molar root canals. Materials and Methods: Eighty extracted mandibular first molar teeth were randomly assigned to 4 groups (n = 20) according to the endodontic access cavity shape and the single file system used for root canal preparation (reciprocating motion with the RCP B and rotary motion with the OC): TEC-RPC B, TEC-OC, CEC-RPC B, and CEC-OC. The apically extruded debris during preparation was collected in Eppendorf tubes. The amount of extruded debris was quantified by subtracting the weight of the empty tubes from the weight of the Eppendorf tubes containing the debris. Data were analyzed using 1-way analysis of variance with the Tukey post hoc test. The level of significance was set at p < 0.05. Results: The CEC-RPC B group showed more apical debris extrusion than the TEC-OC and CEC-OC groups (p < 0.05). There were no statistically significant differences in the amount of apical debris extrusion among the TEC-OC, CEC-OC, and TEC-RPC B groups. Conclusions: RPC B caused more apical debris extrusion in the CEC groups than did the OC single-file system. Therefore, it is suggested that the RPC B file should be used carefully in teeth with a CEC.

• Proceedings of the Safety Management and Science Conference
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• 2011.11a
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• pp.205-211
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• 2011

The papaer reviews four theoretical acceptance sampling plans as OC(Operating Characteristics) curve based inspection, rectifying inspection, switching inspection, and continuous inspection. In addition, the study presents practical limitations of theoretical acceptance sampling by attribute and by variable. Finally, following research also recommends the sampling inspection based on production technology. However, the inspection method requires quality expertise with various experience and implicit knowledge of the field.

• Proceedings of the Safety Management and Science Conference
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• 2008.04a
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• pp.443-450
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• 2008

This paper is to present design principle and operation strategy of acceptance control chart by the use of OC-Based sampling inspection for continuous data. The unified control limits for acceptance control chart when considering both APL(Acceptable Process Level) and RPL(Rejectable Process Level) are proposed. The control limits can be also extended to the acceptance control chart with unknown process standard deviation.

• Journal of the Korean Data and Information Science Society
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• v.19 no.4
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• pp.1183-1189
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• 2008

The general formulas of the operating characteristic(OC) function, average sample number(ASN) and average outgoing quality(AOQ) for the modified n-level skip-lot sampling plan(MMSkSP2) were derived using Markov chain properties by Cho(2008). In this paper, the OC curve, ASN and AOQ of a reference plan, modified two-level, three-level and five-level skip-lot sampling plans are compared.

• Journal of the Korean Data and Information Science Society
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• v.10 no.2
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• pp.437-444
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• 1999

We propose control charts for constant hazard rate by using the number of failures based on the non-placement(replacement) life test. Also we study the sensitivity of the control chart from the operating characteristic curve.

• Geomechanics and Engineering
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• v.29 no.1
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• pp.1-11
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• 2022

A semi-analytical solution to responses of overconsolidated (OC) unsaturated soils surrounding an expanding spherical cavity under constant suction condition is presented. To capture the elastoplastic hydro-mechanical property of OC unsaturated soils, the unified hardening (UH) model for OC unsaturated soil is adopted in corporation with a soil-water characteristic curve (SWCC) and two suction yield surfaces. Taking the specific volume, radial stress, tangential stress and degree of saturation as the four basic unknowns, the problem investigated is formulated by solving a set of first-order ordinary differential equations with the help of an auxiliary variable and an iterative algorithm. The present solution is validated by comparing with available solution based on the modified Cam Clay (MCC) model. Parametric studies reveal that the hydraulic and mechanical responses of spherical cavity expanding in unsaturated soils are not only coupled, but also affected by suction and overconsolidation ratio (OCR) significantly. More importantly, whether hydraulic yield will occur or not depends only on the initial relationship between suction yield stress and suction. The presented solution can be used for calibration of some insitu tests in OC unsaturated soil.

• Restorative Dentistry and Endodontics
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• v.45 no.3
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• pp.30.1-30.11
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• 2020

Objectives: This micro-computed tomographic (CT) study aimed to compare the shaping abilities of ProTaper Next (PTN), One Shape (OS), and One Curve (OC) files in 3-dimensionally (3D)-printed mandibular molars. Materials and Methods: In order to ensure standardization, 3D-printed mandibular molars with a consistent mesiobuccal canal curvature (45°) were used in the present study (n = 18). Specimens were instrumented with the OC, OS, or PTN files. The teeth were scanned pre- and post-instrumentation using micro-CT to detect changes of the canal volume and surface area, as well as to quantify transportation of the canals after instrumentation. Two-way analysis of variance was used for statistical comparisons. Results: No statistically significant differences were found between the OC and OS groups in the changes of the canal volume and surface area before and after instrumentation (p > 0.05). The OC files showed significantly less transportation than the OS or PTN systems for the apical section (p < 0.05). In a comparison of the systems, similar values were found at the coronal and middle levels, without any significant differences (p > 0.05). Conclusions: These 3 instrumentation systems showed similar shaping abilities, although the OC file achieved a lesser extent of transportation in the apical zone than the OS and PTN files. All 3 file systems were confirmed to be safe for use in mandibular mesial canals.

• Current Optics and Photonics
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• v.3 no.6
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• pp.516-521
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• 2019

The electrical leakage levels of GaN-based light-emitting diodes (LEDs) containing leakage paths are estimated using photoluminescence (PL) and photovoltaic properties under photoexcitation conditions. The PL intensity and open-circuit voltage (V_OC) decrease because of carrier leakages depending on photoexcitation conditions when compared with reference values for typical LED chips without leakage paths. Changes of photovoltage-photocurrent characteristics and PL intensity due to carrier leakage are employed to assess the leakage current levels of LEDs with leakage paths. The current corresponding to the reduced V_OC of an LED with leakage from the photovoltaic curve of a reference LED without leakage is matched with the leakage current calculated using the PL intensity reduction ratio and short-circuit current of the LED with leakage. The current needed to increase the voltage for an LED with a leakage under photoexcitation from V_OC of the LED up to V_OC of a reference LED without a leakage is identical to the additional current needed for optical turn-on of the LED with a leakage. The leakage current level estimated using the PL and photovoltaic properties under photoexcitation is consistent with the leakage level measured from the voltage-current characteristic obtained under current injection conditions.