On the Relationship between ??-sensitivity Analysis and Sensitivity Analysis using an Optimal Basis

Park, Chan-Kyoo,Kim, Woo-Je,Park, Soondal 한국경영과학회 2004 Management Science and Financial Engineering Vol.10 No.2

e-sensitivity analysis is a kind of methods for performing sensitivity analysis for linear programming. Its main advantage is that it can be directly applied for interior-point methods with a little computation. Although e-sensitivity analysis was proposed several years ago, there have been no studies on its relationship with other sensitivity analysis methods. In this paper, we discuss the relationship between e-sensitivity analysis and sensitivity analysis using an optimal basis. First, we present a property of e-sensitivity analysis, from which we derive a simplified formula for finding the characteristic region of e-sensitivity analysis. Next, using the simplified formula, we examine the relationship between e-sensitivity analysis and sensitivity analysis using optimal basis when an e-optimal solution is sufficiently close to an optimal extreme solution. We show that under primal nondegeneracy or dual nondegeneracy of an optimal extreme solution, the characteristic region of e-sensitivity analysis converges to that of sensitivity analysis using an optimal basis. However, for the case of both primal and dual degeneracy, we present an example in which the characteristic region of e-sensitivity analysis is different from that of sensitivity analysis using an optimal basis.

민감도분석을 통한 지진하중을 받는 CFRD 정상부 침하량 예측

하익수 한국지반공학회 2007 한국지반공학회논문집 Vol.23 No.1

In this study, quantitative sensitivity analysis on rockfill material influencing the dam crest settlement of CFRD (Concrete-Faced Rockfill Dam) subjected to earthquake loading was carried out. The purpose of this study is to indicate the most important input parameter from the results of sensitivity analysis, to show the quantitative variation of settlement at the crest of CFR type dam during earthquake with this input parameter, and to recommend the approximate estimation method of the settlement on the crest of CFRD subjected to earthquake loading. The statistic characteristics of rockfill parameters which were obtained from large triaxial tests were evaluated. The total 108 dynamic numerical analyses (2 input earthquake, 2 magnitudes for each earthquake, 27 rockfill material property combinations) on CFRD were conducted. The global sensitivity analysis was carried out using the results of numerical analysis. From the sensitivity analysis, It was found that the crest settlement of the CFRD subjected to earthquake was absolutely affected by the shear modulus of rockfill material irrespective of the input earthquakes and the magnitude of input acceleration. On the contrary, it was found that the effect of cohesion and friction angle of rockfill was negligible. From the results of sensitivity analysis and numerical analysis, the approximate estimation method of the settlement on the crest of CFRD subjected to earthquake loading was recommended on condition that the rockfill shear modulus and simple dam information was known.

예비교사용 성인지 감수성 교육 프로그램 효과성 분석

박성희 학습자중심교과교육학회 2022 학습자중심교과교육연구 Vol.22 No.12

Objectives This study was to examine the effects of gender sensitivity education programs for preservice teachers on gender sensitivity and gender role stereotypes. Methods The responses of 60 preservice teachers who faithfully answered the pre- and post-questionnaires among 75 preservice teachers at A University located in the metropolitan area were analyzed. Of these, 32 preservice teachers participated in the gender sensitivity education program as an experimental group, and the remaining 28 preservice teacehrs were participated into a control group. The education program was conducted over 4 sessions, and pre- and post-surveys were conducted immediately before and immediately after the implementation of the gender sensitivity education program. The data were analyzed through descriptive statistics, analysis of covariate variance (ANCOVA), and multivariate analysis of covariance (MANCOVA). Results As a result of the study, firstly, the gender sensitivity education program improved the gender sensitivity of preservice teachers. Secondly, the gender sensitivity education program improved preservice teachers' openness to self-reflection, non-violence, and gender roles among the sub-elements of gender sensitivity. On the other hand, there was no significant difference in openness to gender identity. Lastly, it was found that the gender sensitivity education program significantly lowered the gender role stereotypes of preservice teachers compared to the control group. Conclusions The strategies to improve the gender sensitivity and to make lower the gender role stereotypes of preservice teachers were specified, and points to consider when planning and operating the program for preservice students were suggested. 목적 본 연구는 예비교사들을 대상으로 예비교사용 성인지 감수성 교육 프로그램을 실시하여 성인지 감수성과 성역할 고정관념에미치는 효과를 검증하고자 한다. 방법 이에 수도권에 위치한 A대학교 학부 교직과정에 있는 75명중 사전⋅사후설문에 성실히 응답한 60명의 응답을 분석하였다. 이중 32명은 실험그룹으로 성인지 감수성 교육 프로그램에 참여하였고, 나머지 28명은 통제그룹으로 나뉘어져 진행되었다. 해당교육프로그램은 4차시에 걸쳐서 진행되었으며, 성인지 감수성 교육 프로그램 시행 직전과 직후에 사전⋅사후설문을 실시하였다. 수집된 설문 응답은 기술통계, 공변량분산분석(ANCOVA), 다변량공분산분석(MANCOVA)을 통해 분석하였다. 결과 연구결과 첫째, 예비교사용 성인지 감수성 교육 프로그램은 예비교사들의 성인지 감수성을 향상시켰다. 둘째, 예비교사용 성인지 감수성 교육 프로그램은 예비교사들의 성인지 감수성의 하위요소들 중 자기성찰, 비폭력, 성역할에 대한 개방성을 향상시켰다. 반면, 성정체성에 대한 개방성에서는 유의한 차이가 나지 않았다. 셋째, 예비교사용 성인지 감수성 교육 프로그램은 예비교사들의성역할 고정관념을 통제그룹에 비해 유의하게 낮추는 것으로 나타났다. 결론 예비교사용 성인지 감수성 교육 프로그램을 통해 예비교사들의 성인지 감수성을 향상시키고 성역할 고정관념을 효과적으로 낮출수 있는 전략을 구체화시키며 이를 바탕으로 예비교사용 성인지 감수성 교육프로그램 운영에서 고려사항과 시사점을 논의하였다.

Value range optimization of ply parameter for composite wind turbine blades based on sensitivity analysis

Pengwen Sun,Yin Zhang,Lanting Zhang,Weifei Hu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.3

Blade ply parameters are important design factors that influence the performances of wind turbine blades. This paper proposes a sensitivity analysis method of the blade ply parameters that fuses the relative sensitivity analysis of multi-parameters and the interval sensitivity analysis of single-parameters. A method for identifying the stability region of the sensitive parameters is presented. Coupled mathematical models of the blade static strength and the blade stiffness as a function of the blade ply parameters are established by incorporating experimental design, finite element analysis, and multiple nonlinear regression. The moment independent sensitivity analysis method based on the cumulative distribution function is used to analyze the multi-parameter relative sensitivity, and the direct derivative method was used to analyze single-parameter interval sensitivity. The sensitive and insensitive ply parameters are identified, and the initial stability and instability regions of the ply parameters are determined. A case study of a 1.5 MW blade shows that the ply angle and the ply thickness are sensitive parameters, and the ply stacking sequence is an insensitive parameter. The optimal and stability value ranges of the ply angle and the ±x° ply thickness ratio are [44°, 45°] and [44 %, 48 %], respectively. Hence, the validity and reliability of the proposed method is verified.

Uncertainty and sensitivity analyses for fuel temperature evaluations of U-Mo/Al plate-type dispersion fuel

Sweidan, Faris B.,Tahk, Young-wook,Yim, Jeong-Sik,Ryu, Ho Jin Elsevier 2018 Annals of nuclear energy Vol.120 No.-

<P><B>Abstract</B></P> <P>U-Mo/Al plate-type dispersion fuel is a promising candidate for the conversion of research reactor fuels from highly enriched to low-enriched uranium due to its high uranium density. The fuel temperature is a very important parameter, as it affects the performance of the fuel through various aspects, such as the formation of an interaction layer (IL) between the fuel particles and the matrix, swelling, and the release of fission gas. For these reasons, the fuel temperature as a function of the fission density was calculated for two representative heat flux profiles using best-estimate values and Monte Carlo simulations. Uncertainty and sensitivity analyses which utilized the uncertainties of the critical parameters were then conducted to determine the upper (maximum) and lower (minimum) bounds of the fuel temperature for the selected heat flux profiles. The uncertainty analysis used common uncertainty propagation approaches and a probabilistic sensitivity analysis (Monte Carlo simulation), randomly sampling numbers following a Gaussian distribution. Lastly, the Pearson correlation coefficient was used to identify the input uncertainties which influence the fuel temperature most in the sensitivity analysis. These analyses contribute to safety analyses and to the licensing process, as they are used in best-estimate approaches that apply realistic assumptions complemented with uncertainty analyses, such as the Best Estimate Plus Uncertainty (BEPU) approach.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Uncertainty and sensitivity analyses on U-Mo/Al dispersion fuel were conducted. </LI> <LI> Uncertainties of key parameters on the fuel temperature were evaluated. </LI> <LI> The fuel temperature as a function of the fission density was calculated. </LI> <LI> Pearson correlation coefficient was used to identify the influence of the input uncertainties. </LI> </UL> </P>

A Study on Mesh Size Dependency of Finite Element Blast Structural Analysis Induced by Non-uniform Pressure Distribution from High Explosive Blast Wave

남진원,김장호,김성배,이나현,변근주 대한토목학회 2008 KSCE Journal of Civil Engineering Vol.12 No.4

Accurate computational blast analysis can be an effective replacement for costly blast field test. HFPB (high fidelity physics based)blast analysis method including high strain rate dependent material models and appropriate blast wave models is a representativeprecise blast analysis method. HFPB blast analysis method can be used for various analyses such as structural analysis, retrofittingdesign analysis, fragmentation analysis, and energy absorbing analysis. When analyzing the behaviour of structure under blastloading by HFPB finite element methods, load gradient differences occurs dependent on the mesh size. This causes gaps between theexplosive energy and internal energy of structures and the results of analysis become mesh-size-dependent. In this study, theanalytical considerations were presented for mesh sensitivity due to non-uniform pressure load distribution on the structure subjectedto blast wave of high explosive with relatively close stand-off. Through the analysis results, the maximum element size whichensures the mesh-size independent analysis results is suggested.

Best estimate calculation and uncertainty quantification of sodium-cooled fast reactor using MARS-LMR code

Kang, Seok-Ju,Jeong, Hae-Yong,Bae, Sung-Won,Choi, Chi-Woong,Ha, Kwi-Seok,Suh, Jae-Seung Elsevier 2018 Annals of nuclear energy Vol.115 No.-

<P><B>Abstract</B></P> <P>The safety analysis of nuclear power plants has been performed using conservative approach based on conservative assumptions and boundary conditions to evaluate the safety margin of plant operation. However, this conservative approach could lead to unrealistic behavior predictions and eventually distort some phenomena in reactor systems. Therefore, the nuclear field moved towards an alternative best-estimate approach with uncertainty quantification in order to improve the phenomena prediction and to decrease the excessive conservatism in safety margins. In this study, the best estimate methodology is applied to improve the accuracy and reliability in safety analysis of an SFR. The applied best estimate methodology is based on the CSAU. This methodology is composed of three unique steps for evaluation of code capability, assessment and range of parameters, and sensitivity and uncertainty analysis. The primary purpose of this study is to evaluate the appropriateness of sensitivity parameters and its ranges, which have been determined through intensive experts’ panel discussion, by use of the data obtained from the EBR-II Unprotected Loss of Flow (ULOF) experiment. The MARS-LMR thermal–hydraulic code and the parallel computing platform integrated for uncertainty and sensitivity analysis (PAPIRUS) become the basic calculation tools in the study. Confirmation of data coverage is performed through the evaluation of coolant temperature in the instrumented subassemblies XX09. The appropriateness of parameters and its ranges are evaluated for three different cases: original parameters and ranges suggested in the MIRT, ±10% increased parameter ranges, and 200% increased axial reactivity feedback coefficient only. The case with the original parameters and ranges does not result in a valid data coverage, which means inadequate modeling accuracy for the ULOF scenario. The other two cases give complete coverage of EBR-II temperature data measured at the core top, which suggest the need of further refinement of reactivity models. The relative importance of the parameters is confirmed through the sensitivity analysis with respect to the Figures of Merit (FoM). The selected dominant parameters are the sodium density reactivity, above core load pad strain coefficient, core radial expansion reactivity coefficient and fuel axial expansion reactivity coefficient. The pump coastdown curve and the core inlet form loss are also found to be significant parameters during the transient.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A best-estimate approach based on the CSAU is applied to the ULOF analysis of a pool-type SFR. </LI> <LI> The MARS-LMR code and the PAPIRUS tool are used to perform the uncertainty and sensitivity analyses. </LI> <LI> The sensitivity parameters and its ranges are determined through intensive experts’ panel discussion. </LI> <LI> The data coverage of code models is validated with the coolant temperature measured in EBR-II test. </LI> <LI> The relative importance of parameters is evaluated with the sensitivity study for the FoMs. </LI> </UL> </P>

What Semiotic Values Do Cosmetics Consumers Consume? : Analysis of Cosmetic Brand Reputation and Brand Selection Attributes Using Text Mining

Man Seok Song 한국피부과학연구원 2021 아시안뷰티화장품학술지 Vol.19 No.2

목적: 본 연구는 화장품 소비자가 소셜미디어에 작성한 화장품 브랜드 평판과 선택 속성에 대한 담론적 리뷰로 남긴 주관적 감 성 빅데이터를 크롤링하여 소비자 자신이 구매한 화장품 기호가치 소비를 어떻게 인식하고 있는가에 대해 텍스트 마이닝 분석 기 법인 워드클라우드 분석, 의미연결망 분석, 그리고 감성 분석을 실시하였다. 방법: 빅데이터의 수집과 분석 도구로는 R version 3.6.2-RStudio Version 1.4.1103 프로그램을 이용하여 화장품 소비자가 구매후 남긴 기호가치 경험 리뷰 데이터를 수집하였으며, 수집된 데이터에 대해 데이터의 전처리와 불용어의 설정, 모델링의 실행, 결과 해석까지 총 3단계에 걸쳐 연구를 진행하였다. 결과: 워드클라우드 분석 결과 '피부'라는 단어가 가장 높게 나타났으며 '구입', '자연'이 다음으로 비중이 높게 나타났다. 이들 주제어가 두 드러지게 나타난 것은 화장품 이용 소비자가 기호가치에 의해 구매한 화장품 선택 요인의 경험 가치를 잘 반영하고 있다 할 수 있 다. 의미연결망 분석 결과에서 '자연', '진짜', '제품', '커버', '사용', 그리고 '스킨 화장품' 등의 경우 연결중심성과 매개중심성, 그리고 근접중심성이 높게 나타났으며, 감성 분석 결과 긍정적 반응을 보인 것은 4,742 단어이며, 부정적인 반응 결과 단어는 2,039, 그리 고 중립으로 나타난 단어는 14,146으로 나타났다. 결론: 워드클라우드 분석에서 상위 30위의 주제어들은 화장품 이용 소비자의 구 매 목적과 선택 속성을 잘 나타내고 있는 것으로 보이며 화장품 소비를 위한 요소에서 매우 중요하다는 것을 의미하고 있다. 의미 연결망 분석에서 매개중심성, 연결중심성, 근접중심성 등에서 모두 높게 나타난 '진짜', '제품', 그리고 '스킨 화장품' 등은 일 특정 화 장품 브랜드에 대한 의미의 확산과 연결에 중요한 역할을 한다. 감성 분석 결과 긍정적인 감성 반응이 부정적인 감성 반응보다 약 2.33배 높게 나타난 것은 연구 대상인 일 특정 화장품 브랜드 기업의 브랜드 평판이 좋은 것으로 판단된다. Purpose: This study aims to empirically analyze how consumers perceive their consumption of the semiotic value from cosmetics that they purchased by using text-mining analysis techniques-word cloud analysis, semantic network analysis, and sensitivity analysis-and examining the subjective emotional big data that consumers have left as discourse reviews concerning the brand reputation and selection attributes of cosmetics in social media. Methods: R version 3.6.2-RStudio Version 1.4.1103 was used to collect and analyze the review data on the semiotic value experience that cosmetics consumers left after their purchases. The research was conducted in three stages: the pre-processing of collected data and setting of stopwords, the execution of modeling, and the result analysis. Results: The word cloud analysis evinced that the word “skin” appeared the most, followed by “purchase” and “nature”. The fact that such keywords featured prominently suggests that cosmetics consumers described their experience of their purchased cosmetics based on a semiotic value. The semantic network analysis revealed that “nature”, “product”, “real,” “cover,” “use,” and “skin cosmetics” had high levels of degree centrality, betweenness centrality, and closeness centrality. Finally, through the sensitivity analysis, 4,742 words showing positive reviews, 2,039 words showing negative reviews, and 14,146 showing neutral reviews were found. Conclusion: In the word cloud analysis, the top 30 keywords represented the purchase goal and selection attribute of cosmetics consumers well and are considerably important for consumption factors related to cosmetics. “Real”, “product”, and “skin cosmetics”, all of which were high in betweenness centrality, degree centrality, and closeness centrality in the semantic network analysis, play an important role in spreading and connecting “meaning” toward particular cosmetics brands on a daily basis. Finally, the sensitivity analysis found that positive emotional reviews appeared approximately 2.33 times more often than negative ones.

건물 사용 시나리오에 따른 냉난방 부하 민감도 분석의 불확실성

유영서(Yoo, Young-Seo),이동혁(Yi, Dong-Hyuk),박철수(Park, Cheol-Soo) 대한건축학회 2021 대한건축학회논문집 Vol.37 No.11

It has been widely acknowledged that rational decision making at architectural design stage is important for energy efficient building design. In other words, the relationship between building energy use and design variables must be carefully analyzed. For this purpose, the global sensitivity analysis (GSA) can be a useful tool because GSA quantifies the unit change of a model’s output against the unit change of the individual model input for the entire input space. With the use of GSA, the influence of each design variable can be quantified in terms of sensitivity index. However, such sensitivity index can be dependent on crude assumptions for building usage scenarios, e.g. occupant density, equipment density, infiltration rate, etc. In general, these parameters are set as deterministic values based on simulationist’s subjective judgment, and it can be inferred that this subjective assmptions could cause uncertainty in sensitivity analysis. With this in mind, the authors propose a sensitivity analysis process for building energy design variables considering the uncertainty of building use scenarios. For this purpose, Sobol sensitivity analysis was performed on five design variables (wall U-value, fenestration SHGC, lighting power density, window U-value, window-wall ratio) according to assumptions of five building usage scenarios (occupant density, equipment density, infiltration rate, cooling and heating set-point temperatures). As a result, it is found that uncertainty in the sensitivity of design variables is significant and the sensitivity ranking of the design variables can vary. This indicates that in order to reach rational decision making, careful attention must be paid to selection of uncertain building usage scenarios, and stochastic sensitivity analysis must be employed.

Sensitivity and uncertainty analysis for ULOF of PGSFR using PAPIRUS

Kang, Sarah,Choi, ChiWoong,Ha, Kwi-Seok,Heo, Jaeseok Elsevier 2017 Annals of nuclear energy Vol.110 No.-

<P><B>Abstract</B></P> <P>In this research, sensitivity and uncertainty analyses for 23 parameters were performed for unprotected loss of flow (ULOF) for the prototype Gen-IV sodium-cooled fast reactor (PGSFR) by using the parallel computing platform integrated for uncertainty and sensitivity analysis (PAPIRUS). Based on the development of the phenomena and model identification and ranking table (PIRT), the relative importance of the parameters was confirmed through the sensitivity analysis. The objective of the global uncertainty analysis is to evaluate all safety parameters of the system in the combined phase space formed by the parameters and dependent variables. The uncertainty propagation was performed by mapping the uncertainty bands of the model parameters through the MARS-LMR to determine the distributions for the fuel centerline, cladding, and coolant temperatures. The results show that the uncertainty bands of the temperatures are below the melting point.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sensitivity analysis for the ULOF of the PGSFR was performed using PAPIRUS. </LI> <LI> Uncertainty propagation was performed by mapping uncertainty bands of parameters. </LI> <LI> Distributions for fuel centerline, cladding and coolant temperatures were determined. </LI> </UL> </P>