• Journal of Korean Society for Quality Management
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• v.25 no.3
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• pp.108-118
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• 1997

A commercial nuclear power station contains at least two emergency diesel generates(EDG) to control the risk of severe core demage during the station blackout accidents. Therefore the reliability of the EDG's to start and load-run on demend must be maintained at a sufficiently high level. Until now, a simple assessment of start and load-run success rates was used to calculate the EDG's reliability. However, this method has been found to contain many defects. Recently, the work of Martz et al.(1996) proposed the use of the Bayes estimator to find the EDG's reliability. In this paper, we will propose confidence interval for the Bayes estimator, compare the above two methods and, using practical examples, illustrate why the Bayes estimator method is more reasonable in our situation.

• Proceedings of the KWS Conference
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• v.43
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• pp.67-69
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• 2004

The fuel assemblies as the nuclear fuel for the pressurized water reactor(PWR) are loaded in the reactor core throughout the residence time of three to five years. The spacer grid assembly, which is an interconnected array of slotted grid straps and is welded at the intersections to form an egg crate structure, is one of the main structural components of the fuel assembly. The spacer grid assembly is structurally required to have enough buckling strength under various kinds of lateral load acting on the fuel assembly so as to keep the fuel assembly straight. To meet the requirement, integrity on the spacer grid welding parts should be carefully checked. In this study, welding quality of the spacer grid assembly welded by several welding companies are examined and compared.

• International Commerce and Information Review
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• v.12 no.1
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• pp.123-152
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• 2010

With the change of diverse business environments, the need for the third party logistics(3PL) is strategically considered for securing core abilities of manufacturers' own business. Most manufacturers are willing to have Win-Win relationship with the 3PL companies, instead of working with 3PL companies only for the purpose of reducing costs of logistics. This study has intentions to analyze determination factors of the distribution partnership which influence manufacturing firms within Gyeongsangbuk-do province and effects of partnership which exert an favorable influences on their outcome. With regard to the determination factors, it is found that determination factors consists of shipping quality, crisis management and possession of resources. And for the effects, saving logistics cost, improvement in service quality and strengthening the distribution partnership are included. This study intends to suggest helpful guidelines to business managers who seek a solution for more efficient logistics service.

• Nuclear Engineering and Technology
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• v.31 no.2
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• pp.236-255
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• 1999

An improved mechanistic model was developed to predict a convective boiling critical heat flux (CHF) in the vertical round tubes with uniform heat fluxes. The CHF formula for subcooled and low quality boiling was derived from the local conservation equations of mass, energy and momentum, together with appropriate constitutive relations. The model is characterized by the momentum balance equation to determine the limiting transverse interchange of mass flux crossing the interface of wall bubbly layer and core by taking account of the convective shear effect due to the frictional drag on the wall-attached bubbles. Comparison between the present model predictions and experimental CHF data from several sources shows good agreement over a wide range of How conditions. The present model shows comparable prediction accuracy with the CHF look-up table of Groeneveld et al. Also the model correctly accounts for the effects of flow variables as well as geometry parameters.

• Journal of Korean Society for Quality Management
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• v.26 no.4
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• pp.265-276
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• 1998

A commercial nuclear power station contains at least two emergency diesel generators(EDG) to control the risk of severe core damage during station blackout accidnets. Therefore, thereliability of the EDG's to start and load-run on demand must be maintained at a sufficiently high level. Until now, a simple assessment of start and load-run success rates was used to calculate the EDG reliability. However, this method has been found to contain many defects. Recently, the work of Martz et al.(1996) proposed the use of the Bayes estimator to find EDG reliability. Shim(1996) proposed a confidence interval for the Bayes estimator, compare the above two methods. In this paper, we introduce the notion of "Composite Reliablility" to estimate the reliability of nuclear-power plant EDG, and using practical examples, illustrate which method is more a, pp.opriate in our situation.situation.

• Journal of Korean Society for Quality Management
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• v.32 no.4
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• pp.196-207
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• 2004

TDR(Tear Down & Redesign)means that renounce the past resolutely, from a white paper condition, let's change directions. That is, let's redesign from the basic of the establishment of the construction process. Through the switchover the conception, innovate totally the whole existing processes. TDR is the best core innovation activity. The ultimate aim of the TDR activity induces the employees to do more productive business and obtain excellent results in the future by solving the problems, which are the nonproductive business in the business process on the objective view, the business that customers don't recognize the value, the same old practice of business, and the unsettled business from the restriction of resources. By organizing the related to workers of those business, they can solve the problems for 3-4months by full time working This paper inquires what are the obstruction factors on the process of executing TDR activity. Through the search of the reformation plan for the improvement of immersion degree, it presents some methods to be successful business.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.11a
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• pp.404-410
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• 2006

6시그마 프로세스는 정의(Define), 측정(Measure), 분석(Analyze), 개선(Improve), 관리(Control) 라는 다섯 Step을 통하여 문제를 해결하고 성과를 달성한다. 이 다섯 단계 중에서 측정 단계는 6시그마로는 길에서 매우 중요한 전이 단계로서 문제점을 정교하게 다듬고 근원적 원인 규명을 시작하는 데 도움을 준다. 즉 개선 하고자 하는 영역에 대한 사실적 근거를 제공 받기 위해 프로세스를 숫자로 전환 할 때 무엇을 측정하고 어떻게 측정 할 것인가를 결정한다. 측정단계는 주로 3 Step으로 이루어진다. Step 1 은 CTQ 특성치의 선정, Step 2는 성과기준의 정의, Step 3은 측정시스템의 분석이다. F사의 6시그마 발표자료 중 측정 부분만을 집중 분석하여 문제점 및 그 개선 방향을 제시하려한다.

• Journal of information and communication convergence engineering
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• v.12 no.1
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• pp.53-59
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• 2014

Motion estimation is a core part of most video compression systems since it directly affects the output video quality and the encoding time. The full search (FS) technique gives the highest visual quality but has the problem of a significant computational load. To solve this problem, we present in this paper a modified median (MMED) operation and advanced search strategies for fast motion estimation. The proposed MMED operation includes a temporally co-located motion vector (MV) to select an appropriate initial candidate. Moreover, we introduce a search procedure that reduces the number of thresholds and simplifies the early termination conditions for the determination of a final MV. The experimental results show that the proposed approach achieves substantial speedup compared with the conventional methods including the motion vector field adaptive search technique (MVFAST) and predictive MVFAST (PMVFAST). The proposed algorithm also improves the PSNR values by increasing the correlation between the MVs, compared with the FS method.

• JSTS:Journal of Semiconductor Technology and Science
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• v.2 no.4
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• pp.295-301
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• 2002

In this paper, solenoid-type 3-D passives (inductors and transformers) have been designed, fabricated, and characterized by using electroplating techniques, wire bonding techniques, multi-layer thick photoresist, and low temperature processes which are compatible with semiconductor circuitry fabrication. Two different fabrication approaches are performed to develop the solenoid-type 3-D passives and relationship of performance characteristics and geometry is also deeply investigated such as windings, cross-sectional area of core, spacing between windings, and turn ratio. Fully integrated inductor has a quality factor of 31 at 6 GHz, an inductance of 2.7 nH, and a self resonant frequency of 15.8 GHz. Bonded wire inductor has a quality factor of 120, an inductance of 20 nH, and a self resonant frequency of 8 GHz. Integrated transformers with turn ratios of 1:1 and n:l have the minimum insertion loss of about 0.6 dB and the wide bandwidth of a few GHz.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.06a
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• pp.161-164
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• 1998

Erbium doped garnet crystals were grown by Czochralski method. Relationshipes between crystal quality and crystal growth factors such as pulling rate, rotation rate and concentration of active ions and sensitizers were investigated. Optimum pulling and rotation rate for high quality Er:YAG crystal were 1 mm/hr and 20 rpm and for Er,Cr:YSGG crystal 2-4 mm/hr and 10 rpm respectively. The size of the crystals grown was up to 20-30 mm in diameters and 95-135 mm in length. Er:YAG crystal grown under the nitrogen atmosphere was pink and transparent and Er,Cr:YSGG under the 98% {{{{ { N}_{ 2} }}}} and 2% {{{{ { O}_{2 } }}}} was dark green and transparent. Under the polarizing microscopic observations with crossed polar, striations and {211} core facets were detected. Spectroscopic properties for Er,Cr:YSGG laser rods with <111> axis, 80 mm in length and 6.3 mm in diameter for medical laser applications of 2.79 ${\mu}$m wavelength were manufactured and then laser oscillation was achieved.