Surrogate Model-Based Global Sensitivity Analysis of an I-Shape Curved Steel Girder Bridge under Seismic Loads (지진하중을 받는 I형 곡선거더 단경간 교량의 대리모델 기반 전역 민감도 분석)
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- Journal of the Society of Disaster Information
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- v.19 no.4
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- pp.976-983
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- 2023
Purpose: The dynamic behavior of a bridge structure under seismic loading depends on many uncertainties, such as the nature of the seismic waves and the material and geometric properties. However, not all uncertainties have a significant impact on the dynamic behavior of a bridge structure. Since probabilistic seismic performance evaluation considering even low-impact uncertainties is computationally expensive, the uncertainties should be identified by considering their impact on the dynamic behavior of the bridge. Therefore, in this study, a global sensitivity analysis was performed to identify the main parameters affecting the dynamic behavior of bridges with I-curved girders. Method: Considering the uncertainty of the earthquake and the material and geometric uncertainty of the curved bridge, a finite element analysis was performed, and a surrogate model was developed based on the analysis results. The surrogate model was evaluated using performance metrics such as coefficient of determination, and finally, a global sensitivity analysis based on the surrogate model was performed. Result: The uncertainty factors that have the greatest influence on the stress response of the I-curved girder under seismic loading are the peak ground acceleration (PGA), the height of the bridge (h), and the yield stress of the steel (fy). The main effect sensitivity indices of PGA, h, and fy were found to be 0.7096, 0.0839, and 0.0352, respectively, and the total sensitivity indices were found to be 0.9459, 0.1297, and 0.0678, respectively. Conclusion: The stress response of the I-shaped curved girder is dominated by the uncertainty of the input motions and is strongly influenced by the interaction effect between each uncertainty factor. Therefore, additional sensitivity analysis of the uncertainty of the input motions, such as the number of input motions and the intensity measure(IM), and a global sensitivity analysis considering the structural uncertainty, such as the number and curvature of the curved girders, are required.
Purpose: This study aims to come up with improvement measures to improve the effectiveness of child safety measures. Method: The current status of child safety accidents was investigated and implications were deduced by analyzing major child safety measures by government department in the past. In addition, a perception survey was conducted on 1,000 people including children, guardians, and children's facility workers who are subject to child safety policies. Result: Regarding the safety of children's living space(environment), 35.3% of guardians answered that more than 1/3 of them were not safe. Both guardians(95.3%) and children's facility workers(89%) answered that there was the highest risk of 'traffic accidents', and the second risk factor was parents(carelessness of workers at children's facilities) and children's facility workers(careless of guardians at home). Looking at the risks by place, "road and sidewalk" was the most dangerous place and for child safety, guardians(64.3%) and workers (78.3%) both said that the role of "parent" is the most important. For improvements to prevent child safety accidents, the response rate of "strengthening safety management of road traffic facilities" is the most necessary with 75.8% for guardians and 65% for child use facilities. Conclusion: The reinforcement measures to strengthen the effectiveness of child safety measures are as follows. First, in order to ensure the continuity of child safety measures, it should be operated effectively so that those subject to the establishment of the Comprehensive Plan for Child Safety, which took effect in August 2022, can feel it. Second, in order to improve the sensitivity of children's policy targets, promotion measures that take into account the characteristics of each child safety field should be continuously strengthened. Third, it is necessary to expand safety infrastructure for each field to secure child safety. Fourth, it is necessary to strengthen safety education that can ensure safety for children themselves and to come up with detailed measures to make safety education for parents(guardians) mandatory.
As artificial intelligence (AI) technology is recognized as a key technology that will determine future national competitiveness, competition for AI technology and industry promotion policies in major countries is intensifying. This study aims to present implications for domestic policy making by analyzing the policies of major countries on the start-up of AI companies, which are the basis of the AI industry ecosystem. The top four countries and the EU for the number of new investment attraction companies in the 2023 AI Index announced by the HAI Research Institute at Stanford University in the United States were selected, The United States enacted the National AI Initiative Act (NAIIA) in 2021. Through this law, The US Government is promoting continued leadership in the United States in AI R&D, developing reliable AI systems in the public and private sectors, building an AI system ecosystem across society, and strengthening DB management and access to AI policies conducted by all federal agencies. In the 14th Five-Year (2021-2025) Plan and 2035 Long-term Goals held in 2021, China has specified AI as the first of the seven strategic high-tech technologies, and is developing policies aimed at becoming the No. 1 AI global powerhouse by 2030. The UK is investing in innovative R&D companies through the 'Future Fund Breakthrough' in 2021, and is expanding related investments by preparing national strategies to leap forward as AI leaders, such as the implementation plan of the national AI strategy in 2022. Israel is supporting technology investment in start-up companies centered on the Innovation Agency, and the Innovation Agency is leading mid- to long-term investments of 2 to 15 years and regulatory reforms for new technologies. The EU is strengthening its digital innovation hub network and creating the InvestEU (European Strategic Investment Fund) and AI investment fund to support the use of AI by SMEs. This study aims to contribute to analyzing the policies of major foreign countries in making AI company start-up policies and providing a basis for Korea's strategy search. The limitations of the study are the limitations of the countries to be analyzed and the failure to attempt comparative analysis of the policy environments of the countries under the same conditions.
Based on the questionnaires sent to 270 nurses of public health centers in kyungnam during the period of March 19 to April 11 in 1992, this study was written for the of finding out the grade of satisfaction, obstacles in carrying out duties concerned with nursing services and the change of nurses role needed according to the change of the local public health administration. The first-ranking tasks carried by nurses of public health center are believed to have been family planning activities before the 1970's, nursing services during the 1970's, mother-child health activities during the 1980's, and nursing services during the period of 1990 to 1992. As far as the priority order of all the family planning activities is concerned, the counseling of the insertion of intrauterine contraceptive device, the use of oral pill or the distribution of condom was placed emphasis on before 1970, and publicity activities of family planning after that time. The first priority order of mother-child health activities has been put on the registration of pregnant women since 1970, with prenatal examination and vaccination ranking next to it. The priority order for activities against tuberculosis was laid on finding out and registration of new T.B. patients every year, with patients' control, and medication or injection ranking next to it. As for the priority order of nursing services, traveling medical examination and treatment ranked the first-stressed activity before 1970, with medication and injection ranking next to it. The first priority order management activity of communicable diseases was put on vaccination before 1970, with medication and injection. ranking next. And consultation and education ranked second to it during 1990 to 1992. As for the health services of the aged, traveling examination and treatment ranked the order, with the assistance of medical examination ranking next to it. As far as troubles and obstacles shown in case of family planning, the rate of residents' lack understanding was 28.8%, that of lacking budget 13.6%, and the imperfection of public health administration system 11.9%. In the case of tuberculosis control, residents' lacking understanding was 32.5%, the deficiency of public health administration system 18.2%, over-duty(shortage of hands) 15.6%, and the insufficiency skill and know-how 13.0%. In the case of nursing services, the deficiency of public health administration system was 18.2%, each over-duty(the shortage of hands) and the shortage of facilities and equipment 15.6% respective, and residents' lacking understanding 13.0%. The rate of dissatisfaction with the chance or possibility of promotion for his or her career or capability was shown to be 49.2%, and 65.9% of the health nurses expressed their complaints of the deficiency of the chance of the promotion to a professional or expert. when the public health nurses were asked in the questionably whether they were satisfied or not with current state of equipment and facilities needed for public health service, 49.6% of them answered in the negative. The grade of the satisfaction with the current individual position was shown to be low as much as the status of his or her position was now. 37.6% of those asked in the research answered to have the readiness to switch jobs for the reasons of dissatisfaction and so on with lacking promotion chance as well as bad working condition. Significant correlation between the grade of job satisfaction and the current status of the po as found to be in this research, which showed that the lower the status of position was, the lower the grade of job satisfaction was. But little correlation between the grade of job satisfaction and his or her schooling and career was found. In order to carry out primary health care successfully, it can be said that more education and publicity activities to make public health nurses and residents see it in a new light are requested. In addition to it, it is suggested that the improvement of promotion system for public health nurses and the enlargement of job province should also be taken in consideration of the high dissatisfaction with and complaints of the chance of promotion and the system of position. In order words, it is important that considerations for system improvement enough to make nursing services pleasant and satisfactory should be taken into.
Introduction As consumers' purchase behavior change into a rational and practical direction, the discount store industry came to have keen competition along with rapid external growth. Therefore as a solution, distribution businesses are concentrating on developing PB(Private Brand) which can realize differentiation and profitability at the same time. And as improvement in customer loyalty beyond customer satisfaction is effective in surviving in an environment with keen competition, PB is being used as a strategic tool to improve customer loyalty. To improve loyalty among PB users, it is necessary to develop PB by examining properties of a customer group, first of all, quality level perceived by consumers should be met to obtain customer satisfaction and customer trust and consequently induce customer loyalty. To provide results of systematic analysis on relations between antecedents influenced perceived quality and variables affecting customer loyalty, this study proposed a research model based on causal relations verified in prior researches and set 16 hypotheses about relations among 9 theoretical variables. Data was collected from 400 adult customers residing in Seoul and the Metropolitan area and using large scale discount stores, among them, 375 copies were analyzed using SPSS 15.0 and Amos 7.0. The findings of the present study followed as; We ascertained that the higher company reputation, brand reputation, product experience and brand familiarity, the higher perceived quality. The study also examined the higher perceived quality, the higher customer satisfaction, customer trust and customer loyalty. The findings showed that the higher customer satisfaction and customer trust, the higher customer loyalty. As for moderating effects between PB and NB in terms of influences of perceived quality factors on perceived quality, we can ascertain that PB was higher than NB in the influences of company reputation on perceived quality while NB was higher than PB in the influences of brand reputation and brand familiarity on perceived quality. These results of empirical analysis will be useful for those concerned to do marketing activities based on a clearer understanding of antecedents and consecutive factors influenced perceived quality. At last, discussions about academical and managerial implications in these results, we suggested the limitations of this study and the future research directions. Research Model and Hypotheses Test After analyzing if antecedent variables having influence on perceived quality shows any difference between PB and NB in terms of their influences on them, the relation between variables that have influence on customer loyalty was determined as Figure 1. We established 16 hypotheses to test and hypotheses are as follows; H1-1: Perceived price has a positive effect on perceived quality. H1-2: It is expected that PB and NB would have different influence in terms of perceived price on perceived quality. H2-1: Company reputation has a positive effect on perceived quality. H2-2: It is expected that PB and NB would have different influence in terms of company reputation on perceived quality. H3-1: Brand reputation has a positive effect on perceived quality. H3-2: It is expected that PB and NB would have different influence in terms of brand reputation on perceived quality. H4-1: Product experience has a positive effect on perceived quality. H4-2: It is expected that PB and NB would have different influence in terms of product experience on perceived quality. H5-1: Brand familiarity has a positive effect on perceived quality. H5-2: It is expected that PB and NB would have different influence in terms of brand familiarity on perceived quality. H6: Perceived quality has a positive effect on customer satisfaction. H7: Perceived quality has a positive effect on customer trust. H8: Perceived quality has a positive effect on customer loyalty. H9: Customer satisfaction has a positive effect on customer trust. H10: Customer satisfaction has a positive effect on customer loyalty. H11: Customer trust has a positive effect on customer loyalty. Results from analyzing main effects of research model is shown as