• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.5
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• pp.589-599
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• 2013

The concept of robust optimization is based on Taguchi's method. Especially, robustness indices of objective function pursue an insensitive and conservative design when there are variations on design variables and parameters. To accomplish the purpose, various robustness indices on the objective function have been developed. However, it can be caused limitations to develop the robustness index, because there is difference between the Taguchi's method and robust optimization. In this paper, an investigation is performed to identify the characteristics and the drawbacks of the previous studies. To achieve the purpose, evaluations are conducted by using the examples which have both a deterministic optimum and a robust optimum. Moreover, a new viewpoint as well as a robustness index using a supremum value of the objective function is proposed based on the investigation.

• Proceedings of the Korean Society for Information Management Conference
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• 2006.08a
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• pp.135-142
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• 2006

인용을 통한 연구성과 지표인 h-지수는 2005년에 제안된 이후 공식의 간단명료함, 용이한 산출 방법, 지수의 강건성 등이 인정되면서 계량정보학 분야를 비롯한 학술 공동체의 활발한 후속 논의가 이례적으로 신속하게 이어지고 있다. 후속 연구는 주로 h-지수의 타당성 검토, h-지수를 이용한 특정 분야의 개인성과 측정 시도, h-지수의 타 영역에의 응용, h-지수의 보완 등을 주제로 전개되고 있다. 이 연구에서는 우선 h-지수와 이를 보완한 g-지수를 비롯한 변형 지수에 대해서 현재까지 전개되고 있는 논의를 살펴보았다. 그리고 인용빈도가 높지 않은 경우를 고려하여 개선한 지수를 제안하고 실험적인 측정을 시도하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1426-1435
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• 2003

Design goal is to find the one that has the highest probability of success and the smallest variation. A robustness index has been proposed to satisfy these conditions. The two-step optimization process of the target problem requires a scaling factor. The search process of a scaling factor is replaced with the making of the decoupled design between the mean and the standard deviation. The decoupled design matrix is formed from the sensitivity or the sum of squares. After establishing the design matrix, the robust design process has a new three-step one. The first is ″reduce variability,″ the second is ″make the candidate designs that satisfy constraints and move the mean on the target,″ and the final is ″select the best robust design using the proposed robustness index.″ The robust design process is verified by three examples and the results using the robustness index are compared with those of other indices.

• Journal of the Korean Society for information Management
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• v.23 no.3 s.61
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• pp.167-186
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• 2006

The h-index, also called as Hirsch-index, is a new tool for measuring research outputs by citations. This h-index is not only easy to calculate, but also robust enough to handle various citation data. After its suggestion by Hirsch in 2005, many researchers applied the h-index to their own areas, and some others tried to improve the weak points of the h- index such as low discriminating power. Firstly, several of these efforts are reviewed in the present article, and then novel indexes are suggested to measure research outputs by citations more fairly and reasonably. Calculating these indexes on both artificial data and real data showed that the newly suggested indexes in this article can replace the h-index and its variants.

• Journal of Korea Water Resources Association
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• v.50 no.2
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• pp.121-128
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• 2017

In this study, robustness index and uncertainty analysis were proposed to quantify the risk inherent in the process of climate change vulnerability assessment. The water supply vulnerability for six metropolitan cities (Busan, Daegu, Incheon, Gwangju, Daejeon, and Ulsan), except for Seoul, were prioritized using TOPSIS, a kind of multi-criteria decision making method. The robustness index was used to analyze the possibility of rank reversal and the uncertainty analysis was introduced to derive the minimum changed weights of the criteria that determine the rank reversal between any paired cities. As a result, Incheon and Daegu were found to be very vulnerable and Daegu and Busan were derived to be very sensitive. Although Daegu was relatively vulnerable against the other cities, it can be largely improved by developing and performing various climate change adaptation measures because it is more sensitive. This study can be used as a preliminary assessment for establishing and planning climate change adaptation measure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.10
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• pp.2073-2081
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• 2002

In product design and manufacturing, axiomatic design provides a systematic approach for the decision-making process. Two axioms have been defined such as the Independence Axiom and the Information Axiom. The Information Axiom states that the best design among those that satisfy the independence axiom is the one with the least information content. In other words, the best design is the one that has the highest probability of success. On the other hand, the Taguchi robust design is used in the two-step process; one is "reduce variability," and the other is "adjust the mean on the target." The two-step can be interpreted as a problem that has two FRs (functional requirements). Therefore, the Taguchi method should be used based on the satisfaction of the Independence Axiom. Common aspects exist between the Taguchi method and Axiomatic Design in that a robust design is induced. However, different characteristics are found as well. The Taguchi method does not have the design range, and the probability of success may not be enough to express robustness. Our purpose is to find the one that has the highest probability of success and the smallest variation. A new index is proposed to satisfy these conditions. The index is defined by multiplication of the robustness weight function and the probability density function. The robustness weight function has the maximum at the target value and zero at the boundary of the design range. The validity of the index is proved through various examples.gh various examples.

• The Korean Journal of Applied Statistics
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• v.29 no.2
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• pp.369-379
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• 2016

The Sigma Level, proposed by Motorola Inc., is one of the many Process Capability Index (PCI)'s that have been presented since the 1970's. It is used to evaluate process capability and unlike other PCI's, it has an advantage in that it uses population probability distribution. However, it is originally designed for mass production and is inadequate to evaluate prototypes or early products in the R&D stages. For use in such cases, we propose an R&D target Sigma Level, derived by considering 1.5 sigma shifts in traditional sigma level from a statistical point of view. We also explain the way to find robust limits for design tolerance because the sigma level or defect probability is useful to establish economical tolerance limits at the R&D stage and mass production.

• Journal of the Korea Society of Computer and Information
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• v.28 no.4
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• pp.83-91
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• 2023

In this paper, we propose a robustness sensitivity index (RSI) of highway networks to analyze the effect of congestion in a specific section on the entire highway. The newly proposed RSI is defined as the change in the total mileage of the transportation network per extended unit length when the length of a particular section is extended. When the RSI value is large, traffic congestion in the section has a worse effect on the entire network than in other sections. The existing network robustness index (NRI) simply observes changes in transportation networks with and without specific sections, but the RSI proposed in this study is a kind of performance indicator that allows quantitative analysis of the ripple effect of the entire network according to the degree of congestion in a specific section. While changing the degree of congestion in a particular section, it is possible to calculate how the traffic volume increases, decreases, and the size and location of the congestion section change. This analysis proves the superiority of RSI as it cannot be analyzed with NRI. Various properties of RSI are analyzed using data from the domestic highway network. In addition, using the RSI concept, it is shown that the ripple effect on other sections in which a change in the degree of congestion of a specific section occurs can be analyzed.

• Journal of the Korea Safety Management & Science
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• v.13 no.1
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• pp.175-182
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• 2011

고객의 요구에 대한 빠른 대응과 유연하고 효율적으로 새로운 제품을 적기에 개발하기 위해서는 제품 플랫폼에 기초한 대량 맞춤이 절실히 요구된다. 이러한 목적을 달성하기 위하여 기업들은 상대적으로 생산비용을 낮게 유지하면서 대량생산의 이점을 유지하고 동시에 고객의 요구사항을 만족시키기 위해, product family를 도입하고 가능하면 작은 변화를 통하여 제품의 다양성을 유지하고자 한다. Product family를 설계할 때 중요한 이슈 중에 하나는 제품의 공통성과 차별성간의 절충점을 찾아내는 것인데, 본 연구에서는 설계자들이 product family 재설계를 용이하게 하기 위한 방법론을 제안한다. 이를 위하여 본 연구에서는 ant colony 알고리즘과 product family의 공통성 평가지수를 이용하여 product family 재설계 방법론을 개발한다. 제안한 방법론은 복잡하고 반복적인 많은 계산과정을 가지고 있는 다른 방법과 달리 메타 휴리스틱 알고리즘을 적용하여 인간의 간섭을 줄이고, 실험결과의 정확도, 반복성 및 강건성을 향상시킨다. 본 연구에서는 컴퓨터 마우스 제품군을 대상으로 제안한 방법의 타당성을 검증하였고, 추가적으로 product family 레벨과 부품 레벨의 product family 재설계 추천방안도 제시하였다.

• Journal of the Korean Society for information Management
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• v.27 no.1
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• pp.249-267
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• 2010

The h-index is a new tool for measuring research outputs based on citation and many variants of h-index have been proposed to improve the weaknesses of h-index. The h-index and its variants can be applied to institutional evaluation in three different ways. We worked out 447 practical cases of professors from 10 business schools and examined h-index and its variants. And then we compared three evaluation methods of research institution based on the h-index and its variants.