• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.4
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• pp.117-131
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• 2015

Conventional data envelopment analysis (DEA) models require that inputs and outputs are given as crisp values. Very often, however, some of inputs and outputs are given as imprecise data where they are only known to lie within bounded intervals. While a typical approach to addressing this situation for optimization models such as DEA is to conduct sensitivity analysis, it provides only a limited ex-post measure against the data imprecision. Robust optimization provides a more effective ex-ante measure where the data imprecision is directly incorporated into the model. This study aims to apply robust optimization approach to DEA models with imprecise data. Based upon a recently developed robust optimization framework which allows a flexible adjustment of the level of conservatism, we propose two robust optimization DEA model formulations with imprecise data; multiplier and envelopment models. We demonstrate that the two models consider different risks regarding imprecise efficiency scores, and that the existing DEA models with imprecise data are special cases of the proposed models. We show that the robust optimization for the multiplier DEA model considers the risk that estimated efficiency scores exceed true values, while the one for the envelopment DEA model deals with the risk that estimated efficiency scores fall short of true values. We also show that efficiency scores stratified in terms of probabilistic bounds of constraint violations can be obtained from the proposed models. We finally illustrate the proposed approach using a sample data set and show how the results can be used for ranking DMUs.

• Journal of Korean Philosophical Society
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• v.105
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• pp.1-25
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• 2008

Two subject-matters are discussed in this article, i.e., the characteristics of philosophical dialogue in Upaniṣads and its influence on the typicalness of Hindu philosophy. First of all, it can be epitomized that the philosophical dialogue of Upaniṣads is to be described as an immediate reproduction of knowledge on 'the truth of truth' by means of revelational teaching. Besides, this dialogue serves as an origin by which the liberation-oriented Hindu philosophy is developed after ages. All the details would be set in order as follows; firstly, the philosophical dialogue in Upaniṣads is an archetype of philosophical dialogue in India. Secondly, this dialogue is a germination that gives birth to the typicalness of liberation-oriented Hindu philosophy. Thirdly, as a result, this dialogue is an original model or an archetype of that very typicalness which are to be specialized such as conservatism on tradition, making revelation being absolute, discredit on reasoning, substantial ontology, knowledge-focused soteriology, empirical reproduction of the truth, etc.

• Journal of Environmental Health Sciences
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• v.45 no.2
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• pp.173-185
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• 2019

Objectives: The objectives of this study are to evaluate the accuracy and precision of exposure model ECETOC TRA v.3.1 by comparing model predictions with repeated exposure measurements in Korean workplaces and to investigate the applicability of ECETOC TRA to Korean workplace exposure assessment in K-REACH. Methods: Measured values and work conditions for 14 kinds of chemicals collected from exposure field surveys conducted at 10 companies in Korea were utilized for this study. All possible process categories (PROCs) considered to be relevant to each work process classification were selected and applied to ECETOC TRA as major determining parameters. In order to quantify the accuracy of the model, the lack of agreement (bias, relative bias, precision) was calculated and the risk ratios for each exposure situation between estimated and measured were also compared. Results: The estimated values varied between five and 25 times according to the PROCs for all exposure situations (ESs) based on tasks/chemicals. The results showed that most of the estimated values were below the measured values, and just 13 of 53 tasks were above the measured values. The overall bias and precision were $-2.91{\pm}1.62$ with ECETOC TRA, and we found that ECETOC TRA showed a low level of conservatism when applied to Korean workplaces, similar to previous studies. Conclusions: This study demonstrates that the existed PROC codes have limitations in fully covering various ESs in Korea. In order to improve the applicability of ECETOC TRA in K-REACH, the addition of new PROCs for Korean industries are necessary.

• Ocean Systems Engineering
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• v.9 no.2
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• pp.191-218
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• 2019

The tower-platform interface and mooring system of floating offshore wind turbines (FOWTs) are some of the most critical components with significant influences on overall project costs. In addition to satisfying strength requirements, it is typical and vital to meet fatigue criteria for a service life of 25 years or more. Wind spectra characteristics considered in analysis can penalize fatigue designs, leading to unnecessary costs. The International Electrotechnical Commission (IEC, 2009) recommends the use of site-specific wind data (spectrum, turbulence intensity, etc.) in design of FOWTs, but for offshore sites it is often the case that such data is unavailable and land-based data are used as surrogates in design. For such scenarios, it is worth investigating whether such alternative approach is suitable and accurate, and understanding the consequence of the selection of wind spectral characteristics on fatigue design. This paper addresses the impact of the subsequent selection on fatigue responses of towerbase and mooring system in a FOWT, as a sequel to the paper by Udoh and Zou (2018) which focused on impacts on strength design. The 5 MW semi-submersible FOWT platform with six mooring lines implemented in the preceding study is applied in analysis. Results indicate significant variations in resulting fatigue life with considered wind parameters. Thus, it is critical to apply proper wind spectra characteristics for analysis and design of FOWTs to avoid unnecessary conservatism and costs. Based on the findings of this study, more explicit guidance on the application of turbulence intensities for IEC-recommended models in offshore sites could lead to more accurate load estimates in design of FOWTs.

• International Journal of Computer Science & Network Security
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• v.22 no.4
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• pp.387-393
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• 2022

The article reflects short-term perspectives on the use of information and communication technologies in the training of teachers for higher education. Education is characterized by conservatism, so aspects of systematic development of the industry are relevant to this cluster of social activity. Therefore, forecasting the introduction of innovative elements of ICT training is in demand for the educational environment. Forecasting educational trends are most relevant exactly in the issues of training future teachers of higher education because these specialists are actually the first to implement the acquired professional skills in pedagogical activities. The article aims to consider the existing potential of ICT-based learning, its implementation in the coming years, and promising innovative educational elements that may become relevant for the educational space in the future. The tasks of scientific exploration are to show the optimal formats of synergy between traditional and innovative models of learning. Based on already existing experience, extrapolation of conditions of educational process organization with modeling realities of using information and communication technologies in various learning dimensions should be carried out. Educational trends for the next 3 years are a rather tentative forecast because, as demonstrated by the events associated with the COVID-19 pandemic, the socio-cultural space is very changeable. Consequently, the dynamism of the educational environment dictates the need for a value-based awareness of the information society and the practical use of technological advances. Thus, information and communication technologies are a manifestation of innovative educational strategies of today and become an important component along with traditional aspects of educational process organization. Future higher education teachers should develop a training strategy taking into account the expediency of the ICT component.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.4
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• pp.350-358
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• 2022

Objectives: For chemical risk assessment in workplaces, it is necessary to determine a reference value through hazard assessment. In general, OEL (Occupational Exposure Limit) is used for this value. However, since chemicals with OEL were not enough, the concept of DNEL (Derived No Effect Level) was introduced in chemical safety assessment. In this study, the possibility and approach of applying DNEL for chemical risk assessment in domestic workplaces were investigated. Methods: The characteristics of OEL and DNEL were investigated. In addition, ACGIH TLV and GESTIS DNEL were compared and the corresponding scopes were analyzed among the chemical substances notified in South Korea. Results: OEL and DNEL are similar concepts reflecting reference values that should not be exposed based on health effects. While their evaluation and derivation are determined based on similar information and procedures, they may vary depending on the responsible actor, data availability, principles of judgment, and more. As a result of the comparative analysis of ACGIH TLV and GESTIS DNEL, it was confirmed that there is some correlation between TWA and DNEL. The conservatism of DNEL was around 50%. Additionally, it was found that the available range of DNEL among chemicals in South Korea is considerable. Conclusions: This study showed that DNEL can be applied when assessing the risk of chemical substances in domestic workplaces considering several regards. However, since this is not the same level as OEL, we have proposed a proper approach to carry out risk assessment step by step.

• Korean Journal of Culture and Social Issue
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• v.17 no.4
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• pp.461-483
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• 2011

This study aims to recognize the definite cognition of Korean people about Social Polarization and to define its category. For this study, Qualitative Research is provided to 38 candidates who live in Seoul. The results show that the reason of the social polarization is divided into 4 categories such as Impossible Social Class Change, Can be the middle class, Can be the Rich, Possible Social Class Change. And the solution of polarization is divided into 4 categories such as Progressive Solution, Moderate Progressive Solution, Moderate Conservative Solution, Conservative Solution. On the basis of the cross-tabulation of the reason and solution of polarization, Most of Korean have tendency to cognize the reason of polarization conservatively, but the solution of polarization is cognized progressively. And This study tries to discuss the meaning of the categories and the implications for consensual communication of Social polarization in korean society.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.127-132
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• 2002

Recent deepwater offshore structures in Gulf of Mexico utilize butt welded tubular joints. Application of welded tubular joint includes tendons, production risers, and steel catenary risers. Fatigue life assessment of these joints becomes more critical because the structures to which they are attached are allowed to undergo cyclic and sometimes large displacements around an anchored position. Estimating the fatigue behavior of these tubular members in the design stage is generally conducted by using S-N curves specified in the codes and standards. Applying the stress concentration factor of the welded structure to S-N approach often results in very conservative assessment because the stress field acting on the tubular has a non-uniform distribution through the thickness. Fracture mechanics and fitness for service (FFS) technology have been applied in the design of the catenary risers. This technology enables the engineer to establish proper requirements on weld quality and inspection acceptance criteria to assure satisfactory structural integrity during its design life. It also provides guidance on proper design curves to be used and a methodology for accounting for the effects of non-uniform stress distribution through the wall thickness. An attempt was made to develop set of S-N curves based on fracture mechanics approach by considering non-uniform stress distribution and a threshold stress intensity factor. Series of S-N curves generated from this approach were compared to the existing S-N curves. For flat plate butt joint, the S-N curve generated from fracture mechanics matches with the IIW class 100 curve when initial crack depth was 0.5 mm (0.02"). Similar comparison with API X′ was made for tubular joint.. These initial crack depths are larger than the limits of inspection by current Non-destructive examination (NDE) means, such as Automatic Ultrasonic Inspection (AUT). Thus a safe approach can be taken by specifying acceptance criteria that are close to limits of sizing capability of the selected NDE method. The comparison illustrates conservatism built into the S-N design curve.

• Korean Journal of Culture and Social Issue
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• v.15 no.3
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• pp.447-467
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• 2009

Lakoff's (2002) 'nation-as-family' metaphor suggests that conservatism and liberalism in the United States are based respectively on two different sets of morality, i.e., "strict father" morality and "nurturant parents" morality. He argues that values associated with respective metaphors and political principles derived from them tend to determine certain political attitudes and policy endorsement. Using the priming technique, this study attempted to examine whether "strict father" and "nurturant parents" morality are indeed what underlie very different positions conservatives and liberals take towards people in need. The results supported the Lakoff's idea and demonstrated that, compared to priming "nurturant parents" morality, priming "strict father" morality actually led people to derogate character of those in need and to attribute more responsibility onto them for their economic predicament. This research leads us to reconsider what constitutes politically conservative and liberal attitudes and emphasizes the malleability of political attitudes.

• Journal of Environmental Health Sciences
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• v.50 no.4
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• pp.237-256
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• 2024

Background: Human health and environment exposure assessments of chemicals are essential part for REACH and BPR as well as K-REACH and K-BPR. Several useful exposure assessment tools have been developed and updated to become extensively used during more than fifteen years of chemical registrations under REACH and their updates are still going on. Objectives: Evolution of regulatory tools for environment, workers and consumers exposure assessments under REACH is investigated focusing on why and how tools have been developed and updated for the future regulatory tools in Korea. Methods: REACH regulatory tools including EUSES, ECETOC TRA and CHESAR as well as built-in models SimpleTreat and SimpleBox were chosen with other frequently used Tier 1 and 2 tools. Available resources such as homepage information, background documents, related scientific reports, relevant journal publications, up-to-date lists of new version publications, release notes and user guides were reviewed extensively and summarized using easy-readable Tables and Figures. Results: SimpleTreat and SimpleBox are built-in models both for EUSES and ECETOC TRA (Environment). ECHA's CHESAR contains ECETOC TRA (Workers) and ECETOC TRA (Consumers) as well as EUSES and ECETOC TRA (Environment) for environment exposure assessment while results of Tier 2 Stoffenmanager and ConsExpoWeb can be imported. Evolution of CHESAR from version 1 (2010) to 3.8 (2023) has focused on the compatibility of frequent updates of IUCLID, importing functionality, editability, updated use maps, harmonised conditions of use as well as updates of the built-in tools evolved according to scientific development, refinements of the tool, increased conservatism and user-friendliness. CHESAR Platform 1.0 will soon be published to serve both for REACH and BPR. Conclusions: Updates of the tools can be successfully continued by transparency of the tools, participation of industry sectors for tool refinements and tool developers'/authorities' encouragements of partners/users to jointly innovate tools through scientific researches, tool validations and user feedback.