• Communications for Statistical Applications and Methods
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• v.15 no.6
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• pp.909-923
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• 2008

This paper considers the replacement model and the preventive maintenance model following the expiration of combination warranty for a repairable system. If the system fails after the combination warranty is expired, then it is minimally repaired at each failure. The criterion used to determine the optimal replacement policy and the optimal preventive maintenance policy is the overall value function based on the expected cost rate per unit time and the expected downtime per unit time. The numerical examples are presented for illustrative purpose when the failure time follows a Weibull distribution.

• Proceedings of the Korean Reliability Society Conference
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• 2000.11a
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• pp.299-311
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• 2000

This paper is concerned with the method of estimating lifetime distribution for field data in warranty period and for a situation where some additional field data can be gathered after the warranty period. Implementing the proposed methods in this paper will result in obtaining the more precise product life time estimation and product improvement.

• Proceedings of the Korean Reliability Society Conference
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• 2000.04a
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• pp.109-114
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• 2000

제품의 사용환경에서의 고장데이터는 일반적으로 보증기간 동안 발생하는 클레임을 처리하거나 A/S를 하는 과정에서 얻어지게 되는데 이러한 현장데이터를 적절한 방법으로 분석하여 제품의 신뢰도에 대한 올바른 정보를 얻고 품질개선에 활용하는 것은 기업에 있어서 매우 중요하다. 본 연구에서는 사용현장 데이터의 수집방법 연구와 현장 데이터의 신뢰성 분석 방법의 연구 흐름을 살펴보고 이후 사용현장데이터의 신뢰성 분석 방법연구에 도움을 주는 것이 목적이다.

• The Korean Journal of Applied Statistics
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• v.8 no.2
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• pp.133-145
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• 1995

This paper is concerned with the method of estimating lifetime distribution from field data for repairable products with multiple modes of failure, and is an extension of Bai et al.(1995). The log linear function is considered as a model for describing the relation between failure time of a product and covariates. Using the nonhomogeneous poisson process, general methods for obtaining pseudo maximum likelihood estimators(PMLEs) for the parameters are outlined and specific formulas for Weibull distribution are obtained. Effects of follow-up percentage on the PMLEs are investigated. Extension to case-cohort design is also considered.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.6
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• pp.27-40
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• 2023

This study analyzes the factors affecting the survival of young start-up companies. A youth start-up company was defined as a company with a founder's age under 39. The study was based on evaluation data from 3,540 companies evaluated by the Technology Guarantee Fund to support youth start-up guarantees during the period from 2012 to 2015. In this study, independent variables were defined as founder characteristics, start-up environment, and start-up strategy, and entrepreneurship, knowledge level, and development capabilities were set as variables for start-up characteristics, competition conditions and comparative advantage with alternatives in the start-up environment, and item novelty, commercialization plan and financing plan were set as variables. For variable measurement, the evaluation index of the youth start-up evaluation model of the Technology Guarantee Fund was used. Management performance was defined as the survival of a company, and the survival of 12, 36, 60, and 84 months was measured based on the occurrence of insolvency registered by the Korea Technology Guarantee Fund. The Cox proportional risk model was used for hypothesis testing. As a result of the analysis, knowledge level and development capability were statistically significant in the characteristics of the founder, and the financing plan in the start-up strategy was statistically significant regardless of the survival period. Among the start-up strategies, the novelty of the item had a positive effect on survival after 36 months. Entrepreneurship was significant only in 12-month survival. The most important order for survival was identified in the order of financing plan, knowledge level, item novelty and development capability, of which the founder's knowledge level in the beginning and the funding plan in the second half had the greatest impact.

• Agrochemical news magazine
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• v.20 no.6 s.153
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• pp.50-53
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• 1999

• Korean Association of Arts Management
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• no.56
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• pp.349-380
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• 2020

The paper is to assess the recent changes in Architectural Artworks system in two regional districts, Seoul and Gyeonggi Province, and to propose policies for further improvement. We focused on four aspects: overall pass rate, top-ranked artists' pass rate, proportion of artists ever passed, genre proportion artworks. It is observed that quality of artworks has improved, market monopolization has been eased, and entry to the market has become more active. However, sculptures accounted for the majority. Public art is gradually changing from 'decorative art' to 'site-specific art', and seeking harmony between architecture and surrounding landscape. To keep pace with this new trend, more institutional efforts should be made: fund raising to induce artwork supplies; introducing life-span concept to secure removal and deformation of artwork; imposing artists' follow-up services; imposing penalties against poor management; and authorizing the committee to choose exhibition sites.

• 월간 기계설비
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• no.10 s.183
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• pp.31-33
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• 2005

기계설비공사의 하자담보책임기간은 <건설산업기본법시행령 제30조 관련 별표 4>, <국가를 당사자로 하는 계약에 관한 법 시행규칙 제70조 관련 별표 1> 및 <주택법시행령 제59조 제1항 관련 별표 6>에 의하여 2년 이내로 규정되어 있다. 그러나, 일부 발주기관 및 건설업체에서 기계설비공사의 하자담보책임기간을 법으로 정한 기간을 초과 설정하여 하자보수 비용 및 하자보증수수료 증가 등의 민원이 발생되고 있어, 건설교통부 및 재정경제부는 하자담보책임기간을 법으로 정한 기간을 준수하여 줄 것을 발주기관에 협조 요청한 바 있다. 이와 관련 대한설비건설협회에서는 기계설비공사 하자담보책임기간을 법으로 정한 기간을 정하여 줄 것을, 시공능력 300위 이내의 일반건설업체 대표이사와 하도급계약담당 부서장에게 요청하였다. 또한 계약 체결한 기계설비공사의 하자담보책임기간이 법으로 정한 기간을 상회하는 경우에는 회계통첩에 의하여 계약서상의 기간을 조정하여 하도급계약시에는 법으로 정한 하자담보책임기간을 설정하여 줄 것을 요청하였다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1997.11a
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• pp.34-40
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• 1997

By proxy signatures, proposed by Mambo, a designated signer can sign original's signature instead of original signer. This paper presents new types of digital proxy signatures called partial delegation with threshold delegation. In proxy signatures for partial delegation with threshold delegation, the proxy signer's power to sign messages is shared. In conclusion, we construct proxy signature schemes satisfying our conditions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.63-64
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• 2012

2008년부터 시작된 세계경제 위축은 전 세계 해상물동량 감소로 이어져 컨테이너선업계의 불황이 더욱 심화되고 있다. 선사들은 불황을 극복하기 위하여 여러 가지 전략들을 구사하고 있다. 대부분의 선사들은 잉여 선박의 추가투입으로 감속운항을 통해 선박 운영비용을 절감하고 있는데, 이와 같은 시도는 선사입장에서는 비용절감이 되지만 감속운항이 화물의 정시성을 저해하는 요소로 작용하고 있기 때문에 화주입장에서는 불만요인이 될 수 있다. 이러한 상황에서 'M'선사는 "On Time Delivery"를 보증하기 위해서 아시아-유럽항로에서 새로운 서비스인 Daily Maersk Service를 2011년 10월부터 적용하고 있다. 본 서비스는 아시아발 북유럽행 특정 기간 포트구간 수송에서 100% "On Time Delivery"를 보증하고, 또한 매일 화물수탁을 가능하게 한 신서비스이다. 본 연구에서는 업계 1위를 달리고 있는 'M'선사가 감속운항을 하면서도 화물의 정시성을 높이기 위해 실시하고 있는 Daily Maersk Service를 통하여 가격 경쟁과 더불어 서비스 경쟁에서도 우위를 확보하려는 전략이 효과를 나타내고 있는 지에 대하여 사례연구를 통하여 확인하였다.