• Title/Summary/Keyword: third-order model

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Wave Simulation for Submarine Cable Route of Southwest Sea Offshore Wind Farm Using the SWAN Model (SWAN 모델을 이용한 서남해 해상풍력단지 해저케이블 경과지의 파랑 수치모의)

  • Ryu, Hwang-Jin;Kim, Sang-Ho;Kwoun, Chul-Hui;Cho, Kwang-Woo;Maeng, Jun-Ho
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.21 no.5
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    • pp.583-590
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    • 2015
  • Submarine cable installation is essentials for grid connection between existing power grid and newly produced electricity which will be from offshore wind farm in Southwest sea area of Korea. Especially, submarine cable route and protection method is designed in order to ensure the economical efficiency, workability and stability of submarine cable installation. On this paper, we will give the basic information about the submarine cable route and protection method of offshore wind farm which will be built in Southwest sea area of Korea. For this, we have a numerical simulation at high and low tide based on the third-generation wave model SWAN(Simulating WAves Nearshore) using the long term wave data from Korea Institute of Ocean Science and Technology(KIOST). The results of the study, year mean Hs is 1.03m, Tz is 4.47s and dominant wave direction is NW and SSW When the incident wave direction is NW(Hs: 7.0 m, Tp: 11.76s), the distribution of shallow water design wave height Hs was calculated about 4.0~5.0m at high tide and 2.0~3.0m at low tide. When the incident wave direction is SSW(Hs: 5.84 m, Tp: 11.15s), the distribution of shallow water design wave height Hs was calculated about 3.5~4.5m at high tide and 1.5~2.5m at low tide. The wave direction on a dominant influence in the section of longitude UTM 249749~251349(about 1.6 km) and UTM 251549~267749(about 16.2 km) in the submarine cable route are each NW and SSW. Prominently, wave focusing phenomenon appears between Wi-do and Hawangdeung-do, in this sea area is showing a relatively high wave hight than the surrounding sea areas.

Studies on the Time Distribution of Heavy Storms (暴雨의 時間的 分布에 關한 硏究)

  • Lee, Keun-Hoo
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.26 no.2
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    • pp.69-84
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    • 1984
  • This study was carried out to investigate the time distribution of single storms and to establish the model of storm patterns in korea. Rainfall recording charts collected from 42 metheorological stations covering the Korean peninsula were analyzed. A single storm was defined as a rain period seperated from preceding and succeeding rainfall by 6 hours and more. Among the defined single storms, 1199 storms exceeding total rainfall of 80 mm were qualified for the study. Storm patterns were cklassified by quartile classification method and the relationship between cummulative percent of rainfalls and cummulative storm time was established for each quartile storm group. Time distribution models for each stations were prepared through the various analytical and inferential procedures. Obtained results are summarized as follows: 1. The percentile frequency of quartile storms for the first to the fourth quartile were 22.0%, 26.5%, 28.9% and 22.6%, respectively. The large variation of percentile frequency was show between the same quartile storms. The advanced type storm pattern was predominant in the west coastal type storm patterns predominantly when compared to the single storms with small total rainfalls. 3. The single storms with long storm durations tended to show delayed type storm patterns predominantly when compared to the single storms with short storm durations. 4. The percentile time distribution of quartile storms for 42 rin gaging stations was estimated. Large variations were observed between the percentiles of time distributions of different stations. 5. No significant differences were generally found between the time distribution of rainfalls with greater total rainfall and with less total rainfall. This fact suggests that the size of the total rainfall of single storms was not the main factor affecting the time distribution of heavy storms. 6. Also, no significant difference were found between the time distribution of rainfalls with long duration and with short duration. The fact indicates that the storm duration was no the main factor affecting the time distribution of heavy storms. 7. In Korea, among all single storms, 39.0% show 80 to 100mm of total rainfall which stands for the mode of the frequency distribution of total rainfalls. The median value of rainfalls for all single storms from the 42 stations was 108mm. The shape of the frequency distribution of total rainfalls showed right skewed features. No significant differences were shown in the shape of distribution histograms for total rainfall of quartile storms. The mode of rainfalls for the advanced type quartile storms was 80~100mm and their frequencies were 39~43% for respective quartiles. For the delayed type quartile storms, the mode was 80~100mm and their frequencies were 36!38%. 8. In Korea, 29% of all single storms show 720 to 1080 minutes of storm durations which was the highest frequency in the frequency distribution of storm durations. The median of the storm duration for all single storms form 42 stations was 1026 minutes. The shape of the frequency distribution was right skewed feature. For the advanced type storms, the higher frequency of occurrence was shown by the single storms with short durations, whereas for the delayed type quartile storms, the higher frequency was shown gy the long duration single storms. 9. The total rainfall of single storms was positively correlated to storm durations in all the stations throughout the nation. This fact was also true for most of the quartile storms. 10. The third order polynomial regression models were established for estimating the time distribution of quartile storms at different stations. The model test by relative error method resulted good agreements between estimated and observed values with the relative error of less than 0.10 in average.

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A Study on the Impact Factors of Contents Diffusion in Youtube using Integrated Content Network Analysis (일반영향요인과 댓글기반 콘텐츠 네트워크 분석을 통합한 유튜브(Youtube)상의 콘텐츠 확산 영향요인 연구)

  • Park, Byung Eun;Lim, Gyoo Gun
    • Journal of Intelligence and Information Systems
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    • v.21 no.3
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    • pp.19-36
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    • 2015
  • Social media is an emerging issue in content services and in current business environment. YouTube is the most representative social media service in the world. YouTube is different from other conventional content services in its open user participation and contents creation methods. To promote a content in YouTube, it is important to understand the diffusion phenomena of contents and the network structural characteristics. Most previous studies analyzed impact factors of contents diffusion from the view point of general behavioral factors. Currently some researchers use network structure factors. However, these two approaches have been used separately. However this study tries to analyze the general impact factors on the view count and content based network structures all together. In addition, when building a content based network, this study forms the network structure by analyzing user comments on 22,370 contents of YouTube not based on the individual user based network. From this study, we re-proved statistically the causal relations between view count and not only general factors but also network factors. Moreover by analyzing this integrated research model, we found that these factors affect the view count of YouTube according to the following order; Uploader Followers, Video Age, Betweenness Centrality, Comments, Closeness Centrality, Clustering Coefficient and Rating. However Degree Centrality and Eigenvector Centrality affect the view count negatively. From this research some strategic points for the utilizing of contents diffusion are as followings. First, it is needed to manage general factors such as the number of uploader followers or subscribers, the video age, the number of comments, average rating points, and etc. The impact of average rating points is not so much important as we thought before. However, it is needed to increase the number of uploader followers strategically and sustain the contents in the service as long as possible. Second, we need to pay attention to the impacts of betweenness centrality and closeness centrality among other network factors. Users seems to search the related subject or similar contents after watching a content. It is needed to shorten the distance between other popular contents in the service. Namely, this study showed that it is beneficial for increasing view counts by decreasing the number of search attempts and increasing similarity with many other contents. This is consistent with the result of the clustering coefficient impact analysis. Third, it is important to notice the negative impact of degree centrality and eigenvector centrality on the view count. If the number of connections with other contents is too much increased it means there are many similar contents and eventually it might distribute the view counts. Moreover, too high eigenvector centrality means that there are connections with popular contents around the content, and it might lose the view count because of the impact of the popular contents. It would be better to avoid connections with too powerful popular contents. From this study we analyzed the phenomenon and verified diffusion factors of Youtube contents by using an integrated model consisting of general factors and network structure factors. From the viewpoints of social contribution, this study might provide useful information to music or movie industry or other contents vendors for their effective contents services. This research provides basic schemes that can be applied strategically in online contents marketing. One of the limitations of this study is that this study formed a contents based network for the network structure analysis. It might be an indirect method to see the content network structure. We can use more various methods to establish direct content network. Further researches include more detailed researches like an analysis according to the types of contents or domains or characteristics of the contents or users, and etc.

An Empirical Comparison and Verification Study on the Containerports Clustering Measurement Using K-Means and Hierarchical Clustering(Average Linkage Method Using Cross-Efficiency Metrics, and Ward Method) and Mixed Models (K-Means 군집모형과 계층적 군집(교차효율성 메트릭스에 의한 평균연결법, Ward법)모형 및 혼합모형을 이용한 컨테이너항만의 클러스터링 측정에 대한 실증적 비교 및 검증에 관한 연구)

  • Park, Ro-Kyung
    • Journal of Korea Port Economic Association
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    • v.34 no.3
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    • pp.17-52
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    • 2018
  • The purpose of this paper is to measure the clustering change and analyze empirical results. Additionally, by using k-means, hierarchical, and mixed models on Asian container ports over the period 2006-2015, the study aims to form a cluster comprising Busan, Incheon, and Gwangyang ports. The models consider the number of cranes, depth, birth length, and total area as inputs and container twenty-foot equivalent units(TEU) as output. Following are the main empirical results. First, ranking order according to the increasing ratio during the 10 years analysis shows that the value for average linkage(AL), mixed ward, rule of thumb(RT)& elbow, ward, and mixed AL are 42.04% up, 35.01% up, 30.47%up, and 23.65% up, respectively. Second, according to the RT and elbow models, the three Korean ports can be clustered with Asian ports in the following manner: Busan Port(Hong Kong, Guangzhou, Qingdao, and Singapore), Incheon Port(Tokyo, Nagoya, Osaka, Manila, and Bangkok), and Gwangyang Port(Gungzhou, Ningbo, Qingdao, and Kasiung). Third, optimal clustering numbers are as follows: AL(6), Mixed Ward(5), RT&elbow(4), Ward(5), and Mixed AL(6). Fourth, empirical clustering results match with those of questionnaire-Busan Port(80%), Incheon Port(17%), and Gwangyang Port(50%). The policy implication is that related parties of Korean seaports should introduce port improvement plans like the benchmarking of clustered seaports.

A longitudinal analysis of high school students' dropping out: Focusing on the change pattern of dropout, changes in school violence and school counseling. (전국 고등학교 학생의 학업중단에 대한 종단적 분석 -학업중단 변화양상에 따른 유형탐색, 학교폭력 및 학교상담의 변화추이를 중심으로-)

  • Kwon, Jae-Ki;Na, Woo-Yeol
    • Journal of the Korean Society of Child Welfare
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    • no.59
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    • pp.209-234
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    • 2017
  • This study viewed schools as a cause of students dropping out and posited that dropping out of high school would vary depending on the characteristics and influencing factors of the school from which students were dropping out. Therefore, focusing on schools, we longitudinally investigated the change patterns of school dropout across high schools in the country, and the types of changes in dropping out of high school. In addition, we predicted the general characteristics of schools according to the type of school students were dropping out from, looked at the changes in the major factors (i.e., school violence and school counseling) affecting school dropout, and reviewed schools' long-term efforts and outcomes in relation to school dropout. For this purpose, KERIS EDSS's "Secondary School Information Disclosure Data" were used. The final model included data collected five years20122016) from high schools across the country. The results were as follows. First, in order to examine the longitudinal change patterns of dropping out of high schools, a latent growth models analysis was conducted, and it revealed that, as time passed, the dropout rate decreased. Second, growth mixture modeling was used to explore types according to the change patterns of the school students were dropping out from. The results showed three types: the "remaining in school" type, the "gradually decreasing school dropout" type, and the "increasing school dropping out". Third, the multinomial logistic regression was conducted to predict the general characteristics of schools by type. The results showed that public schools, vocational schools, and schools with a large number of students who have below the basic levels in Korean, English and mathematics were more likely to belong to the "increasing school dropout" type. Further, the larger the total number of students, the higher the probability of belonging to the "remaining in school" type or the "gradually decreasing school dropout" type. Lastly, growth mixture modeling was used to analyze the trend of school violence and school counseling according to the three types. The focus was on the "gradually decreasing school dropout" type. In the case of the "gradually decreasing school dropout" type, it was found that as time passed, the number of school violence cases and the number of offenders gradually decreased. In addition, in terms of change in school counseling the results revealed that the number of placement of professional counselors in schools increased every year and peer counseling was continuously promoted, which may account for the "gradually decreasing school dropout" type.

The Effects of a Teacher Training Program for Elementary and Middle School Teachers: Focusing on International School for Geoscience Resources (초·중등 교원연수 프로그램의 효과 분석: 국제지질자원인재개발센터를 중심으로)

  • Lee, Yun Su;Kim, Hyoungbum
    • Journal of the Korean Society of Earth Science Education
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    • v.12 no.1
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    • pp.82-93
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    • 2019
  • The purpose of this study is to analyze the results of satisfaction for learning eco-system on the teacher training program conducted at the IS-Geo (International School for Geoscience Resources) which is KIGAM (Korea Institute of Geoscience and Mineral Resources), and to determine the satisfaction and educational effects of the teacher training programs on elementary and secondary teachers. And then, to suggest improvement points in the future operation of the teacher training program at the IS-Geo. Therefore, we conducted questionnaire of satisfaction for learning eco-system based on the data collected by a survey of 98 elementary and secondary teachers who participated in the teacher training program at the IS-Geo, from July 2017 to August 2018. The research results are as follows. First, the results of satisfaction for learning eco-system showed high values of 4.58 or higher in both the elementary and secondary programs, and the teacher training program conducted by the IS-Geo had a positive effect on the training participants. Second, internal factors indicating learning motivation and learning development were elementary teacher training 4.70 and secondary teacher training 4.64, and it is necessary to develop training contents and programs by classifying them into majors other than the earth science department. Third, intermediate factors indicating contents of education and learning curriculum were 4.67 for an elementary teacher training program and 4.72 for secondary teacher training program. In addition, in order to operate the teacher training program according to the purpose of science and technology culture, it is necessary to develop a teaching-learning model and to improve the quality of teaching. Fourth, external factors indicating learner support and quality of instructors were 4.83 for an elementary teacher training program and 4.72 for a secondary teacher training program. In particular, it is necessary to develop teaching materials that can be used immediately in school classes and can generate interest.

Study on Korean SMEs' Brand Luxuriousness Building (마케팅 믹스를 활용한 한국 중소기업의 브랜드 명품성 구축에 대한 연구)

  • Koh, InKo
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.13 no.6
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    • pp.1-14
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    • 2018
  • As interest and consumption of luxury goods have become more popular, luxury goods market is growing rapidly. Consumers can acquire psychological satisfaction with material abundance by purchasing and using luxury goods. Also, from the view of corporations, luxury goods have price inelastic characteristics, so they can enjoy price premium and it is good to produce good performance. That is the reason why they should pay much attention to securing luxuriousness. This study examined the establishment of brands luxuriousness in Korean SMEs. First, it examined the world market of luxury goods industry and the present condition of Korean market. Then it identified the constituents of luxuriousness by examining the prior studies and related literatures, and designed a research model based on the theoretical grounds to suggest the methods of brand luxuriousness building of Korean SMEs. Luxuriousness can be defined as the attribute of product that distinguishes luxury goods from other products by consumers' perceptions, and the factor that provides situational benefits that motivate consumers' purchasing behavior. In this study, I identified the sub-dimensions of luxuriousness according to whether there are product related attributes and consumers' benefit in consideration of the problems of existing studies. Product related luxuriousness are classified into superiority(functional benefit) and scarcity(experiential benefit), while non-product related luxuriousness are classified into differentiation(symbolic benefit) and traditionality(exclusive benefit). The following are the ways to build brand luxuriousness. First, company can use product factors. High quality, excellent design, high recognized brand with strong, favorable and unique images can enhance the luxuriousness of brand. Second, company can use price factors. Consumers tend to perceive luxury goods as high-priced items, so lowering the price of product can undermine the luxuriousness of product. Third, company can use distribution factors. It is effective for making consumers to perceive the differentiation and scarcity of luxuriousness through limited distribution channel. In addition, store atmosphere suitable for luxury brands should be created. Fourth, company can use promotion factors. The more consumers are exposed to advertisements, the more positive attitudes toward luxury brands are made, and consumers recognize luxuriousness higher. Price promotion negatively affects consumers' perception of luxuriousness. Fifth, company can use corporate factors. Consumer evaluations of products are influenced not only by the product attributes but also by the corporate association and corporate image surrounding the product. Considering the existing researches, it is possible to enhance the brand luxuriousness through high corporate competence and good corporate reputation. In order to increase the competence of the enterprise, it is useful to approach multidimensionally in relation with the knowledge creation capability. In corporate reputation, the external stakeholders' reputation is important, but the internal members' reputation is also important. Korean SMEs will be able to build brand luxuriousness by establishing marketing strategies as above and/or mix(integrate) them according to the situation.

The Impact of Care Workers' Employment Characteristics and Perception of Facility Directors' Transformational Leadership on Quality of Service (요양보호사의 고용특성과 시설장에 대한 변혁적 리더십 인식이 서비스 질에 미치는 영향에 관한 연구)

  • Kim, Hye Ji;Park, Sang Hee;Kim, Bum Jung
    • 한국노년학
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    • v.41 no.2
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    • pp.217-240
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    • 2021
  • The purpose of this study is to examine the effect of care workers' employment characteristics and perception of facility directors' transformational leadership on quality of service through a hierarchical linear model. For this aim, survey data were collected amongst 240 older adults and 200 care workers who are affiliated within 45 long-term care facilities in Seoul, and analyzed using SPSS 26.0 and HLM 8.0. As a result, one's perception of transformational leadership had a positive effect, whereas, among employment characteristics, employment type and working hours had negative effects on quality of service. Regular workers with fewer working hours and higher awareness of transformational leadership toward the director provided higher quality of service. But wage, total experience and tenure didn't meaningfully affect it. Therefore, the following suggestions were presented. First, it is necessary to reorganize incentive, salary systems and budgets, changing the status of temporary workers' hourly wage system into that of regular workers' monthly one in order to strengthen employment security with acknowledging fundamental professional values through reinforcement of expertise. Reinforcement of long-term care's publicness and establishment of base facilities are also suggested. Second, maintaining appropriate hours of work and rest including annual leave under the Labor Standards Act is needed. Also, increasing the salary of and decreasing working hours for night shift workers are required. Third, education and intervention for inspiring transformational leadership of directors and strengthening qualification standards of them are required.

Research on the Digital Twin Policy for the Utilization of Administrative Services (행정서비스 활용을 위한 디지털 트윈 정책 연구)

  • Jina Ok;Soonduck Yoo;Hyojin Jung
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.23 no.3
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    • pp.35-43
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    • 2023
  • The purpose of this study is to research digital twin policies for the use of administrative services. The study was conducted through a mobile survey of 1,000 participants, and the results are as follows. First, in order to utilize digital twin technology, it is necessary to first identify appropriate services that can be applied from the perspective of Gyeonggi Province. Efforts to identify digital twin services that are suitable for Gyeonggi Province's field work should be prioritized, and this should lead to increased efficiency in the work. Second, Gyeonggi Province's digital twin administrative services should prevent duplication with central government projects and establish a model that can be connected and utilized. It should be driven around current issues in Gyeonggi Province and the demands of citizens for administrative services. Third, to develop Gyeonggi Province's digital twin administrative services, a standard model development plan through participation in pilot projects should be considered. Gyeonggi Province should lead the project as the main agency and promote it through a collaborative project agreement. It is suggested that a support system for the overall project be established through the Gyeonggi Province Digital Twin Advisory Committee. Fourth, relevant regulations and systems for the construction, operation, and management of dedicated departments and administrative services should be established. To achieve the realization of digital twins in Gyeonggi Province, a dedicated organization that can perform various roles in project promotion and operation, as well as legal and institutional improvements, is necessary. To designate a dedicated organization, it is necessary to consider expanding and reorganizing existing departments and evaluating the operation of newly established departments. The limitation of this study is that it only surveyed participants from Gyeonggi Province, and it is recommended that future research be conducted nationwide. The expected effect of this study is that it can serve as a foundational resource for applying digital twin services to public work.

The Effect of Entrepreneurial Competence and Perception of Entrepreneurship Opportunities on Entrepreneurial Intention: Focusing on the Mediating Effect of Entrepreneurship Opportunity Assessment (중장년 직장인의 창업 개인역량 및 창업기회인식이 창업의도에 미치는 영향: 창업기회평가의 매개효과를 중심으로)

  • Ju Young Jin
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.18 no.3
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    • pp.45-60
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    • 2023
  • In this study, we analyzed the influence of middle-aged office workers' entrepreneurial competency and entrepreneurial opportunity recognition on entrepreneurial intention by mediating entrepreneurial opportunity evaluation. Sub-variables of entrepreneurial competency were classified into prior knowledge, positive attitude, and social network. For the empirical analysis of this study, an online survey using Naver Office was conducted for about 15 days (February 6, 2023 - February 20, 2023) targeting office workers across the country who are interested in starting a business, and a total of 262 copies were collected and missing values. For 250 copies excluding 12 copies, SPSS Ver.24.0 and PROCESS MACRO Model 4.0 were used for empirical analysis. The results of the analysis are as follows: First, the higher the prior knowledge of the founder's individual competency, social network, and entrepreneurial opportunity recognition, the higher the entrepreneurial opportunity evaluation and entrepreneurial intention. On the other hand, it was found that the positive attitude among entrepreneurs' individual competencies did not affect entrepreneurship opportunity evaluation and entrepreneurial intention. In addition, the magnitude of the influence on entrepreneurial opportunity evaluation and entrepreneurial intention was in the order of entrepreneurial opportunity recognition, prior knowledge, and social network. This is because the positive attitude of middle-aged office workers towards start-up has a negative image of start-up due to the shrinking start-up environment due to COVID-19, fear of failure due to lack of preparation for start-up, and successive cases of start-up failure due to cognitive bias errors due to overconfidence. implying that there is Second, it was found that the evaluation of entrepreneurship opportunities had a significant positive (+) effect on entrepreneurial intention in a situation where the entrepreneur's individual competency and entrepreneurial opportunity recognition were controlled. Third, the startup opportunity evaluation was shown to mediate between the prior knowledge of the entrepreneur's individual competency, social network and entrepreneurial opportunity recognition, and entrepreneurial intention, but it did not mediate between positive attitude and entrepreneurial intention. Fourth, among the factors influencing entrepreneurial opportunity evaluation and entrepreneurial intention, entrepreneurial opportunity recognition was found to be larger than founder's individual competency, confirming the importance of entrepreneurial opportunity recognition. Fifth, it was found that prior knowledge and network, which are individual capabilities of the founder, affect the evaluation of entrepreneurial opportunities and entrepreneurial intention, so that strengthening entrepreneurship education to recognize the importance of cultivating prior entrepreneurial knowledge and experience can revitalize middle-aged office workers' entrepreneurship. confirmed.

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