• 산업경영시스템학회지
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• 제40권3호
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• pp.27-37
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• 2017

As the global uncertainty of manufacturing has increased and the quality problem has become global, the recall has become a fatal risk that determines the durability of the company. In addition, as the convergence of PSS (product-service system) product becomes common due to the development of IT convergence technology, if the function of any part of hardware or software does not operate normally, there will be a problem in the entire function of PSS product. In order to manage the quality of such PSS products in a stable manner, a new approaches is needed to analyze and manage the hardware and software parts at the same time. However, the Fishbone diagram, FTA, and FMEA, which are widely used to interpret the current quality problem, are not suitable for analyzing the quality problem by considering the hardware and software at the same time. In this paper, a quality risk assessment model combining FTA and FMEA based on defect rate to be assessed daily on site to manage quality and fishbone diagram used in group activity to solve defective problem. The proposed FTA-FMEA based risk assessment model considers the system structure characteristics of the defect factors in terms of the relationship between hardware and software, and further recognizes and manages them as risk. In order to evaluate the proposed model, we applied the functions of ITS (intelligent transportation system). It is expected that the proposed model will be more effective in assessing quality risks of PSS products because it evaluates the structural characteristics of products and causes of defects considering hardware and software together.

• 한국지구과학회지
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• 제31권5호
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• pp.437-447
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• 2010

Spatial estimation of environmental variables has been regarded as an important preliminary procedure for decision-making. A minimum variance criterion, which has often been adopted in traditional kriging algorithms, does not always guarantee the optimal estimates for subsequent decision-making processes. In this paper, a geostatistical framework is illustrated that consists of uncertainty modeling via stochastic simulation and risk modeling based on loss functions for the selection of optimal estimates. Loss functions that quantify the impact of choosing any estimate different from the unknown true value are linked to geostatistical simulation. A hybrid loss function is especially presented to account for the different impact of over- and underestimation of different land-use types. The loss function-specific estimates that minimize the expected loss are chosen as optimal estimates. The applicability of the geostatistical framework is demonstrated and discussed through a case study of copper mapping.

• Journal of the Korean Data and Information Science Society
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• 제25권4호
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• pp.915-920
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• 2014

We consider a continuous time surplus process with investments the sizes of which are independent and identically distributed. It is assumed that an investment of the surplus to other business is made, if and only if the surplus reaches a given sufficient level. We establish an integro-differential equation for the distribution function of the surplus and solve the equation to obtain the moment generating function for the stationary distribution of the surplus. As a consequence, we obtain the first and second moments of the level of the surplus in an infinite horizon.

• 디자인학연구
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• 제14권1호
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• pp.103-110
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• 2001

본 연구는 제품지향성과 지각된 가격수준에 따라 심미적 반응에 대한 전형성효과가 어떻게 달라지는지를 검증하고자 하기 위한 것이다. 본 연구를 통하여 기존연구가 전형성과 선호도간의 관계에 대한 의견의 일치를 보이지 못하는 것과 관련하여 제품지향성과 지각된 가격수준으로 세분화하여 분석함으로써 그러한 한계점을 극복하고 결과적으로 심미적 반응에 대한 전형성의 효과를 검증하였다. 본 연구의 결과를 통하여 디자인지향적 제품의 경우에는 전형성과 선호도간의 역U자형 관계를 나타내고 있을 것으로 파악되었으나 상대적으로 기능지향적 제품의 경우에는 전형성과 선호도와의 관계는 나타나지 않았다.

• Nuclear Engineering and Technology
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• 제41권6호
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• pp.849-858
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• 2009

Risk caused by safety-critical instrumentation and control (I&C) systems considerably affects overall plant risk. As digitalization of safety-critical systems in nuclear power plants progresses, a risk model of a digitalized safety system is required and must be included in a plant safety model in order to assess this risk effect on the plant. Unique features of a digital system cause some challenges in risk modeling. This article aims at providing an overview of the issues related to the development of a static fault-tree-based risk model. We categorize the complicated issues of digital system probabilistic risk assessment (PRA) into four groups based on their characteristics: hardware module issues, software issues, system issues, and safety function issues. Quantification of the effect of these issues dominates the quality of a developed risk model. Recent research activities for addressing various issues, such as the modeling framework of a software-based system, the software failure probability and the fault coverage of a self monitoring mechanism, are discussed. Although these issues are interrelated and affect each other, the categorized and systematic approach suggested here will provide a proper insight for analyzing risk from a digital system.

• 한국인터넷방송통신학회논문지
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• 제9권6호
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• pp.135-139
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• 2009

어선의 안전을 실시간으로 모니터링하고 위험요소가 발생했을 경우에 사용자에게 이를 경보하고 통보해줄 수 있는 장치에 대한 필요성이 크게 대두되고 있다. 위험요소를 감지하는 다기능 센서를 사용하기 위해서 임베디드 모듈에서는 Device driver와 Application program을 구현해야 하는 문제가 있다. 본 논문에서는 Device driver와 Application program의 구현 없이 다기능 센서의 입출력 데이터를 관리 및 처리하기 위해서 PIC18F를 이용하여 센서부의 하드웨어 설계 및 제어프로그램 구현을 하였다. 센서의 동작에 따라 데이터를 출력하는 동작 확인을 통하여 성능검증을 하였다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2001년도 추계학술대회 논문집
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• pp.157-160
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• 2001

Firms pursue new business opportunities for growth. Market development strategy is one of the growth strategies, which develops new market segments with current products. However, new market generally has high uncertainty, or high risk. Firms should consider the risk in making and implementing the market development strategy. In this paper, an optimal marketing resource allocation model is developed, taking into account the risk attitude of a firm in market development. Under the assumption of exponential utility function, the global optimal solution is derived, and the implications are provided.

• East Asian mathematical journal
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• 제37권1호
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• pp.79-85
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• 2021

In this paper, we investigate the valuation of vulnerable exchange option that has credit risk of option issuer. The reduced-form model is used to model credit risk. We assume that credit event is determined by the jump of the counting process with stochastic intensity, which follows the mean reverting process. We propose a simple approach to derive the closed-form pricing formula of vulnerable exchange option under the reduced-form model and provide the pricing formula as the standard normal cumulative function.

• 재무관리연구
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• 제2권1호
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• pp.21-34
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• 1986

The purpose of this study is to analyse the risk and uncertainty involved in the capital budgeting which is executed in long periods and requires massive capital expenditure. Under risk and uncertainty conditions, the estimates in the capital budgeting are random variables rather than known constants. Two approaches have emerged in performing economic analysis that explicitly incorporate risk and uncertainty conditions in the analysis. One approach is to develop a descriptive model which describes the economic performance of an individual investment alternative. But no recomendation would be forthcoming from the model. Rather, the decision-maker would be furnished descriptive information concerning each alternative; the final choice among the alternatives would required a separate action. The second approach is to develop a normative model which includes an objective function to be maximized or minimized. The output from the model prescribes the course of action to be taken. Owing to the fact that the normative approach considers the fitness of criteria for decision-making its reasonableness looks better. But it is almost imposible that we correctly and easily derive the individuals' utility function. So within we recognize the limits of the descriptive methods, it is more practicle to analyse the investment alternatives by sensitivity analysis.

• Journal of Chest Surgery
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• 제30권9호
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• pp.885-890
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• 1997

.저자들은 1994년 7월부터 1996년 6월까지 관상동맥우회 술을 시행한 환자 103명을 심실구축력 40%를 기준 으로 심실기능저하군 24명과 심실기능정상군 79명으로 분류하여 환자의 술전,수술변수 18개를 분석하였다. 분석결과 환자의 특성과 수술사망에 영향을 미치는 위험인자에 대해 다음과 같은 결과를 얻었다. 1. 술전 변수중 심비대(p=0.0012), 혈청 크레아티닌 이상(p=0.0166), IABP 실시(p=0.0096)는 기능저하군이 기능 정상군보다 유의하게 높은 빈도를 보였다 2. 수술변수중 기능저하군은 수술적응증에 있어서 심근경색후 협심증의 빈도가 많았고(p=0.00003), 내흉동맥 의 사용은 유의하게 적었다(p=0.00416). 3. 조기사망률은 기능저하군이 기능정상군보다 약간 높았으나 통계적으로 유의한 차이는 없었다(기능저하군 8.3%, 기능정상군 5.1%, p=0.5492). 4. 합병증발생률은 기능저하군 50%(12/24), 기능정상군 33%(79/25)로 두군간에 유의한 차이는 없었다(p=0.1007). 5. 심실기능정상군에서는 연령(고령)(p=0.041)이 수술후 조기사망에 유의한 위험인자로, 심실기능저하군에서 는 연령(p=0.018)외에도 술전 IAaP 실시(p=0.0036), 고콜레스테롤혈증(p=0.00 7), 응급수술(p=0.0036)이 유의 한 위험인자로 작용하였다. 이상의 결과를 통해 심실기능이 저하된 관상동맥질환 환자는 심실기능이 정상인 환자에 비해 많은 술후 조기사망의 위험인자를 갖고있으나.술후 조기사망률과 합병증 발생률은 두 군간에 유의한 차이를 보이지 않 음으로써 심실기능이 저하된 환자에 있어서도 증상의 개선과 장기생존률의 향상을 얻기 위하여 좀더 적극적인 관상동맥우회 술의 실시가 필요할 것으로 생각된다.