• Title/Summary/Keyword: Big Five model

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Influence of Thru Holes Near Leading Edge of a Model Propeller on Cavitation Behavior (균일류에서 프로펠러 앞날 근처 관통구가 모형 프로펠러 캐비테이션에 미치는 영향)

  • Ahn, Jong-Woo;Park, Il-Ryong;Park, Young-Ha;Kim, Je-In;Seol, Han-Shin;Kim, Ki-Sup
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.3
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    • pp.281-289
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    • 2019
  • In order to investigate the influence of thru holes near leading edge of model propeller on cavitation behavior, a model propeller with thru holes was manufactured and tested at Large Cavitation Tunnel (LCT). The pressure distribution around the thru hole on propeller blade was numerically calculated to help understand the local flow characteristics related to cavitation behavior. The model propeller is a five bladed propeller which has 2 blades with thru holes and 3 blades with smooth surface. The cavitation observation tests were conducted at angles of $0^{\circ}$ & $6^{\circ}$ using an inclined-shaft dynamometer in LCT. There are big difference on the suction side cavitation behavior each other due to the existence of thru hole. While the blades with thou holes start generation of the sheet cavitation from the leading edge on the suction side, the blades with smooth surface generate the cloud cavitation from the mid-chord. Cavitation on the blades with thru holes shows more similar behavior to those of the full-scale propeller of which the pipe line for air injection is closed. The numerical analysis result shows that the sharp pressure drop occurs around thru holes on the blade. Consequently, the thru hole around leading edge stimulates the cavitation occurrence and stabilizes the cavitation behavior. Based on these results, the effect of thru holes on propeller cavitation behavior behind a model ship should be studied in the future.

Predicting of the Severity of Car Traffic Accidents on a Highway Using Light Gradient Boosting Model (LightGBM 알고리즘을 활용한 고속도로 교통사고심각도 예측모델 구축)

  • Lee, Hyun-Mi;Jeon, Gyo-Seok;Jang, Jeong-Ah
    • The Journal of the Korea institute of electronic communication sciences
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    • v.15 no.6
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    • pp.1123-1130
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    • 2020
  • This study aims to classify the severity in car crashes using five classification learning models. The dataset used in this study contains 21,013 vehicle crashes, obtained from Korea Expressway Corporation, between the year of 2015-2017 and the LightGBM(Light Gradient Boosting Model) performed well with the highest accuracy. LightGBM, the number of involved vehicles, type of accident, incident location, incident lane type, types of accidents, types of vehicles involved in accidents were shown as priority factors. Based on the results of this model, the establishment of a management strategy for response of highway traffic accident should be presented through a consistent prediction process of accident severity level. This study identifies applicability of Machine Learning Models for Predicting of the Severity of Car Traffic Accidents on a Highway and suggests that various machine learning techniques based on big data that can be used in the future.

A study on Model of Personal Information Protection based on Artificial Intelligence Technology or Service (인공지능 기술/서비스 기반의 개인정보 보호 모델에 대한 연구)

  • Lee, Won-Tae;Kang, JangMook
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.16 no.4
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    • pp.1-6
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    • 2016
  • A.I. has being developed from the technology for Big data analysis to the technology like a human being. The sensing technology of IOT will make A.I. have the more delicate sense than human's five senses. The computer resource is going to be able to support A.I. by clouding networking technology wherever and whenever. Like this A.I. is getting developed as a golden boy of the latest technologies At the same time, many experts have the anxiety and bleak outlook about A.I. Most of dystopian images of the future come out when the contemplative view is lost or it is not possible to view the phenomena objectively. Or it is because of the absence of confidence and ability to convert from the visions of technology development to the subject visions of human will. This study is not about the mass dismissal, unemployment or the end of mankind by machinery according to the development of A.I. technology and service, but more about the occurrent issue like the personal information invasion in daily life. Also the ethical and institutional models are considered to develop A.I. industry protecting the personal information.

Factors affecting success and failure of Internet company business model using inductive learning based on ID3 algorithm (ID3 알고리즘 기반의 귀납적 추론을 활용한 인터넷 기업 비즈니스 모델의 성공과 실패에 영향을 미치는 요인에 관한 연구)

  • Jin, Dong-su
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.2
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    • pp.111-116
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    • 2019
  • New technologies such as the IoT, Big Data, and Artificial Intelligence, starting from the Web, mobile, and smart device, enable new business models that did not exist before, and various types of Internet companies based on these business models has been emerged. In this research, we examine the factors that influence the success and failure of Internet companies. To do this, we review the recent studies on business model and examine the variables affecting the success of Internet companies in terms of network effect, user interface, cooperation with actors, creating value for users. Using the five derived variables, we will select 14 Internet companies that succeeded and failed in seven commercial business model categories. We derive decision tree by applying inductive learning based on ID3 algorithm to the analysis result and derive rules that affect success and failure based on derived decision tree. With these rules, we want to present the strategic implications for actors to succeed in Internet companies.

The Effect of Cafe Atmosphere on Purchase Decision: Empirical Evidence from Generation Z in Indonesia

  • BUDIMAN, Santi;DANANJOYO, Radyan
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.4
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    • pp.483-490
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    • 2021
  • In Indonesia, coffee shops, commonly called warung or kedai shops, have begun to appear amid society from remote villages to urban centers. Therefore, the purpose of this study is to examine the effect of cafe atmosphere (i.e., exterior, interior, interior point-of-purchase displays and store layout) on the purchase decision of Generation Z. This study is conducted because of cafe competition is currently overgrowing. This study model consisted of five variables: exterior, interior, interior point-of-purchase displays, store layout, and purchase decision. Sampling in this study used non-probability, with a purposive sampling technique. According to predetermined criteria, the data collection technique employed a questionnaire distributed online to consumers had visited a cafe at least once in the last three months. This study's sample was 137 cafe visitors in Yogyakarta, representing one of the big cities in Indonesia. Therefore, the data was analyzed by using multiple regression. The results of the study indicated that the exterior and interior had a positive and significant effect on purchasing decision. Likewise, interior point-of-purchase displays and store layout positively and significantly affected purchase decision. In addition, this study's findings generally concluded that the cafe atmosphere had a positive and significant effect on purchase decision.

A Study on the Improvement of Information Security Model for Precision Medicine Hospital Information System(P-HIS) (정밀의료 병원정보시스템(P-HIS) 정보보호모델 개선 방안에 관한 연구)

  • Dong-Won Kim
    • Convergence Security Journal
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    • v.23 no.1
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    • pp.79-87
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    • 2023
  • Precision Medicine, which utilizes personal health information, genetic information, clinical information, etc., is growing as the next-generation medical industry. In Korea, medical institutions and information communication companies have coll aborated to provide cloud-based Precision Medicine Hospital Information Systems (P-HIS) to about 90 primary medical ins titutions over the past five years, and plan to continue promoting and expanding it to primary and secondary medical insti tutions for the next four years. Precision medicine is directly related to human health and life, making information protecti on and healthcare information protection very important. Therefore, this paper analyzes the preliminary research on inform ation protection models that can be utilized in cloud-based Precision Medicine Hospital Information Systems and ultimately proposes research on ways to improve information protection in P-HIS.

A Study on Receptivity to Sharing Living Space in Communal Shared Housing of the Elderly Living in Rural Areas depending on Personal Traits

  • Kim, Hyun-Jung;Lee, Yeun-Sook;An, So-Mi
    • KIEAE Journal
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    • v.16 no.4
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    • pp.5-20
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    • 2016
  • Purpose: The objective of this study is to divide personal traits of the elderly living in a rural area into extraversion, agreeableness, openness, conscientiousness, neuroticism, and loneliness and to identify the relationship between personal traits and receptivitiy to sharing living space in communal shared housing. Method: Subjects of this study are the elderly of ages greater than 55 living in Yeongwol-gun, Gangwon-do. Depending on how often elderly welfare facility was used, places where the elderly gathered were divided into a senior citizen center, senior welfare center, and other places where they often gathered. The researchers visited each of the places directly and conducted a survey with face-to-face interviews. Result: The collected data consisting of 124 respondents were analyzed through SPSS statistical program. It showed that 5 personal traits, except for agreeableness, had statistically significant difference. Extrovert and low lonely elderly people had high receptivity. The relationship between personal traits and acceptable shared space revealed differently depending on the function of space. Especially, shared resting space was related to low emotion-oriented trait, such as neuroticism and loneliness, while shared hobby and sanitary space were related to strong management-oriented trait of conscientiousness. These findings demonstrate the importance of understanding personal traits in predicting receptivitiy to sharing living space. Also, it is necessary to compare the degree of receptivity to sharing living space based on personal traits and to plan shared space in several levels, such as full sharing, partial sharing, and individual use, to develop and supply communal shared housing successfully.

Link Prediction in Bipartite Network Using Composite Similarities

  • Bijay Gaudel;Deepanjal Shrestha;Niosh Basnet;Neesha Rajkarnikar;Seung Ryul Jeong;Donghai Guan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.17 no.8
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    • pp.2030-2052
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    • 2023
  • Analysis of a bipartite (two-mode) network is a significant research area to understand the formation of social communities, economic systems, drug side effect topology, etc. in complex information systems. Most of the previous works talk about a projection-based model or latent feature model, which predicts the link based on singular similarity. The projection-based models suffer from the loss of structural information in the projected network and the latent feature is hardly present. This work proposes a novel method for link prediction in the bipartite network based on an ensemble of composite similarities, overcoming the issues of model-based and latent feature models. The proposed method analyzes the structure, neighborhood nodes as well as latent attributes between the nodes to predict the link in the network. To illustrate the proposed method, experiments are performed with five real-world data sets and compared with various state-of-art link prediction methods and it is inferred that this method outperforms with ~3% to ~9% higher using area under the precision-recall curve (AUC-PR) measure. This work holds great significance in the study of biological networks, e-commerce networks, complex web-based systems, networks of drug binding, enzyme protein, and other related networks in understanding the formation of such complex networks. Further, this study helps in link prediction and its usability for different purposes ranging from building intelligent systems to providing services in big data and web-based systems.

The Prediction of Export Credit Guarantee Accident using Machine Learning (기계학습을 이용한 수출신용보증 사고예측)

  • Cho, Jaeyoung;Joo, Jihwan;Han, Ingoo
    • Journal of Intelligence and Information Systems
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    • v.27 no.1
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    • pp.83-102
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    • 2021
  • The government recently announced various policies for developing big-data and artificial intelligence fields to provide a great opportunity to the public with respect to disclosure of high-quality data within public institutions. KSURE(Korea Trade Insurance Corporation) is a major public institution for financial policy in Korea, and thus the company is strongly committed to backing export companies with various systems. Nevertheless, there are still fewer cases of realized business model based on big-data analyses. In this situation, this paper aims to develop a new business model which can be applied to an ex-ante prediction for the likelihood of the insurance accident of credit guarantee. We utilize internal data from KSURE which supports export companies in Korea and apply machine learning models. Then, we conduct performance comparison among the predictive models including Logistic Regression, Random Forest, XGBoost, LightGBM, and DNN(Deep Neural Network). For decades, many researchers have tried to find better models which can help to predict bankruptcy since the ex-ante prediction is crucial for corporate managers, investors, creditors, and other stakeholders. The development of the prediction for financial distress or bankruptcy was originated from Smith(1930), Fitzpatrick(1932), or Merwin(1942). One of the most famous models is the Altman's Z-score model(Altman, 1968) which was based on the multiple discriminant analysis. This model is widely used in both research and practice by this time. The author suggests the score model that utilizes five key financial ratios to predict the probability of bankruptcy in the next two years. Ohlson(1980) introduces logit model to complement some limitations of previous models. Furthermore, Elmer and Borowski(1988) develop and examine a rule-based, automated system which conducts the financial analysis of savings and loans. Since the 1980s, researchers in Korea have started to examine analyses on the prediction of financial distress or bankruptcy. Kim(1987) analyzes financial ratios and develops the prediction model. Also, Han et al.(1995, 1996, 1997, 2003, 2005, 2006) construct the prediction model using various techniques including artificial neural network. Yang(1996) introduces multiple discriminant analysis and logit model. Besides, Kim and Kim(2001) utilize artificial neural network techniques for ex-ante prediction of insolvent enterprises. After that, many scholars have been trying to predict financial distress or bankruptcy more precisely based on diverse models such as Random Forest or SVM. One major distinction of our research from the previous research is that we focus on examining the predicted probability of default for each sample case, not only on investigating the classification accuracy of each model for the entire sample. Most predictive models in this paper show that the level of the accuracy of classification is about 70% based on the entire sample. To be specific, LightGBM model shows the highest accuracy of 71.1% and Logit model indicates the lowest accuracy of 69%. However, we confirm that there are open to multiple interpretations. In the context of the business, we have to put more emphasis on efforts to minimize type 2 error which causes more harmful operating losses for the guaranty company. Thus, we also compare the classification accuracy by splitting predicted probability of the default into ten equal intervals. When we examine the classification accuracy for each interval, Logit model has the highest accuracy of 100% for 0~10% of the predicted probability of the default, however, Logit model has a relatively lower accuracy of 61.5% for 90~100% of the predicted probability of the default. On the other hand, Random Forest, XGBoost, LightGBM, and DNN indicate more desirable results since they indicate a higher level of accuracy for both 0~10% and 90~100% of the predicted probability of the default but have a lower level of accuracy around 50% of the predicted probability of the default. When it comes to the distribution of samples for each predicted probability of the default, both LightGBM and XGBoost models have a relatively large number of samples for both 0~10% and 90~100% of the predicted probability of the default. Although Random Forest model has an advantage with regard to the perspective of classification accuracy with small number of cases, LightGBM or XGBoost could become a more desirable model since they classify large number of cases into the two extreme intervals of the predicted probability of the default, even allowing for their relatively low classification accuracy. Considering the importance of type 2 error and total prediction accuracy, XGBoost and DNN show superior performance. Next, Random Forest and LightGBM show good results, but logistic regression shows the worst performance. However, each predictive model has a comparative advantage in terms of various evaluation standards. For instance, Random Forest model shows almost 100% accuracy for samples which are expected to have a high level of the probability of default. Collectively, we can construct more comprehensive ensemble models which contain multiple classification machine learning models and conduct majority voting for maximizing its overall performance.

Transfer Impedence of Trip Chain with a Railway Mode Embedded - Using Seoul Metroplitan Transportation Card Data - (철도수단이 내재된 통행사슬의 환승저항 추정방안 - 수도권 교통카드자료를 활용하여 -)

  • Lee, Mee young;Sohn, Jhieon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.6
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    • pp.1083-1091
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    • 2016
  • This research uses public transportation card data to analyze the inter-regional transfer times, transfer frequencies, and transfer resistance that passengers experience during transit amongst the metropolitan public transportation modes. Currently, mode transfers between bus and rail are recorded up to five times during one transit movement by Trip Chain, facilitating greater comprehension of intermodal movements. However, lack of information on what arises during these transfers poses a problem in that it leads to an underestimation of transfer resistances on the Trip Chain. As such, a path choice model that reflects passenger movements during transit activities is created, which attains explanatory power on transfer resistance through its inclusion of transfer times and frequencies. The methodology adopted in this research is to first conceptualize the idea of metropolitan public transportation transfer, and in the case that mode transfers include the city-rail, to newly conceptualize the idea of transfer resistance using transportation card data. Also, the city-rail path choice model within the Trip Chain is constructed, with transfer time and frequency used to reevaluate transfer resistance. Further, in order to align bus and city-rail station administrative level small-zone coordinates to state and regional level mid-zone coordinates, the big node methdod is utilized. Finally, case studies on trip chains using at least one transfer onto the city-rail is used to determine the validity of the results obtained.