• Title/Summary/Keyword: latent class 모델

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A Study on Site Repeat Visit and Purchase Decision-Making of On-line Consumer using Two-Stage Mixture Regression Analysis - Focus on Internet Shopping Mall - (2단계 Mixture Model을 이용한 온라인 소비 자의 방문행동특성이 사이트 재방문과 구매에 미치는 영향에 관한 연구 - 온라인 쇼핑몰을 중심으로 -)

  • Lee, Young-Seung
    • Journal of Global Scholars of Marketing Science
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    • v.13
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    • pp.135-158
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    • 2004
  • On-line consumers have some visit behavior characteristics when they visit internet-shopping mall between visit-stage and purchase-stage. Therefore, information of on-line consumers have influenced on internet-shopping mall's profitabilities at site manager's perspectives. For examples, Are any on-line consumers continuous visiting under any situations? Or are any on-line consumers purchased on any specific internet-shopping mall? Expecially in this paper, researcher tried to understand visit behavioral characteristics of on-line consumers using two-stage mixture regression analysis. Throughout this process, it could be proposed method, which could be reinforced competitiveness of internet-shopping mall by segmental decision-making method. Additionally, it is expected that visit behavioral characteristics' information could be supplied strategic implications between visit-stage and purchase-stage Throughout empirical test it could be proved two-stage decision-making process, which decision-making process of on-line consumers would be processed visit-stage and purchase-stage. In this study, researcher proposed suitable response strategy after understanding visiting behavioral characteristics of on-line consumers. This paper has some academical contributions, which visit behavioral characteristics of on-line consumers could be grasped the meaning by site stickiness and navigation pattern.

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Numerical Simulations on Combustion Considering Propellant Droplet Atomization and Evaporation of 500 N Class Hydrogen Peroxide / Kerosene Rocket Engine (500 N급 과산화수소/케로신 로켓엔진의 추진제 액적 분무와 증발을 고려한 연소 수치해석)

  • Ha, Seong-Up;Lee, Seon-Mi;Moon, In-Sang;Lee, Soo-Yong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.10
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    • pp.862-871
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    • 2012
  • The numerical simulations on 500-N class rocket engine using 96% hydrogen peroxide and kerosene have been conducted, considering atomization, evaporation, mixing and combustion of its propellants. The grid containing 1/6 part of combustion chamber has been generated and it is assumed that 3 kinds of liquid-phase propellants (kerosene, hydrogen peroxide and water) were injected as hollow cone spray pattern, using Rosin-Rammler function for distribution of droplet diameter. For the calculation of combustion the eddy-dissipation model was applied. Owing to small size of combustion chamber and large specific heat / latent heat of hydrogen peroxide and water the propulsion characteristics were highly influenced by the size of droplet particles, and in this analysis the engine with droplet particles of 30 micron in average has shown the best propulsion performance.

A Prestigious University Students' Perceptions of their Educational Attainment by a Topic model (토픽모델을 활용한 명문대 재학생의 학벌에 관한 인식 분석)

  • Young Son Jung;Seung-Yun Lee
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.3
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    • pp.503-512
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    • 2024
  • This study examines the essays of academic background, written by students from a university, which is classified into prestigious universities in Korean society. By Latent Dirichlet Allocation, 172 essays were analyzed to explore the students' perspectives of the academic fractionalism. The analysis identified five topics such as, functional aspects (Topic 1), double-edged nature (Topic 2), power communities (Topic 3), symbols of victory (Topic 4), and dysfunctional aspects (Topic 5). The most frequently appearing keywords are 'individual,' 'status,' and 'means' in Topic 1, 'definition,' 'school,' and 'meaning' in Topic 2, 'people,' 'origin,' and 'power' in Topic 3, 'university,' 'ability,' and 'effort' in Topic 4, and 'academic achievement,' 'South Korea,' and 'origin' in Topic 5. By exploring the topics, we found that students regarded class reproduction by education as important social issues and they showed little interest in other factors influencing academic fractionalism, such as race or ethnicity. these findings suggest that professars, who teach the impact of education on academic fractionalism, deal with the influence of diverse factors on academic fractionalism.

Sensitivity of Typhoon Simulation to Physics Parameterizations in the Global Model (전구 모델의 물리과정에 따른 태풍 모의 민감도)

  • Kim, Ki-Byung;Lee, Eun-Hee;Seol, Kyung-Hee
    • Atmosphere
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    • v.27 no.1
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    • pp.17-28
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    • 2017
  • The sensitivity of the typhoon track and intensity simulation to physics schemes of the global model are examined for the typhoon Bolaven and Tembin cases by using the Global/Regional Integrated Model System-Global Model Program (GRIMs-GMP) with the physics package version 2.0 of the Korea Institute of Atmospheric Prediction Systems. Microphysics, Cloudiness, and Planetary boundary Layer (PBL) parameterizations are changed and the impact of each scheme change to typhoon simulation is compared with the control simulation and observation. It is found that change of microphysics scheme from WRF Single-Moment 5-class (WSM5) to 1-class (WSM1) affects to the typhoon simulation significantly, showing the intensified typhoon activity and increased precipitation amount, while the effect of the prognostic cloudiness and PBL enhanced mixing scheme is not noticeable. It appears that WSM1 simulates relatively unstable and drier atmospheric structure than WSM5, which is induced by the latent heat change and the associated radiative effect due to not considering ice cloud. And WSM1 results the enhanced typhoon intensity and heavy rainfall simulation. It suggests that the microphysics is important to improve the capability for typhoon simulation of a global model and to increase the predictability of medium range forecast.

Anomaly Detection for User Action with Generative Adversarial Networks (적대적 생성 모델을 활용한 사용자 행위 이상 탐지 방법)

  • Choi, Nam woong;Kim, Wooju
    • Journal of Intelligence and Information Systems
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    • v.25 no.3
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    • pp.43-62
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    • 2019
  • At one time, the anomaly detection sector dominated the method of determining whether there was an abnormality based on the statistics derived from specific data. This methodology was possible because the dimension of the data was simple in the past, so the classical statistical method could work effectively. However, as the characteristics of data have changed complexly in the era of big data, it has become more difficult to accurately analyze and predict the data that occurs throughout the industry in the conventional way. Therefore, SVM and Decision Tree based supervised learning algorithms were used. However, there is peculiarity that supervised learning based model can only accurately predict the test data, when the number of classes is equal to the number of normal classes and most of the data generated in the industry has unbalanced data class. Therefore, the predicted results are not always valid when supervised learning model is applied. In order to overcome these drawbacks, many studies now use the unsupervised learning-based model that is not influenced by class distribution, such as autoencoder or generative adversarial networks. In this paper, we propose a method to detect anomalies using generative adversarial networks. AnoGAN, introduced in the study of Thomas et al (2017), is a classification model that performs abnormal detection of medical images. It was composed of a Convolution Neural Net and was used in the field of detection. On the other hand, sequencing data abnormality detection using generative adversarial network is a lack of research papers compared to image data. Of course, in Li et al (2018), a study by Li et al (LSTM), a type of recurrent neural network, has proposed a model to classify the abnormities of numerical sequence data, but it has not been used for categorical sequence data, as well as feature matching method applied by salans et al.(2016). So it suggests that there are a number of studies to be tried on in the ideal classification of sequence data through a generative adversarial Network. In order to learn the sequence data, the structure of the generative adversarial networks is composed of LSTM, and the 2 stacked-LSTM of the generator is composed of 32-dim hidden unit layers and 64-dim hidden unit layers. The LSTM of the discriminator consists of 64-dim hidden unit layer were used. In the process of deriving abnormal scores from existing paper of Anomaly Detection for Sequence data, entropy values of probability of actual data are used in the process of deriving abnormal scores. but in this paper, as mentioned earlier, abnormal scores have been derived by using feature matching techniques. In addition, the process of optimizing latent variables was designed with LSTM to improve model performance. The modified form of generative adversarial model was more accurate in all experiments than the autoencoder in terms of precision and was approximately 7% higher in accuracy. In terms of Robustness, Generative adversarial networks also performed better than autoencoder. Because generative adversarial networks can learn data distribution from real categorical sequence data, Unaffected by a single normal data. But autoencoder is not. Result of Robustness test showed that he accuracy of the autocoder was 92%, the accuracy of the hostile neural network was 96%, and in terms of sensitivity, the autocoder was 40% and the hostile neural network was 51%. In this paper, experiments have also been conducted to show how much performance changes due to differences in the optimization structure of potential variables. As a result, the level of 1% was improved in terms of sensitivity. These results suggest that it presented a new perspective on optimizing latent variable that were relatively insignificant.

A Longitudinal Study on the Influence of Attitude, Mood, and Satisfaction toward Mathematics Class on Mathematics Academic Achievement (수학수업 태도, 분위기, 만족도가 수학 학업성취도에 미치는 영향에 대한 종단연구)

  • Kim, Yongseok
    • Communications of Mathematical Education
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    • v.34 no.4
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    • pp.525-544
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    • 2020
  • There are many factors that affect academic achievement, and the influences of those factors are also complex. Since the factors that influence mathematics academic achievement are constantly changing and developing, longitudinal studies to predict and analyze the growth of learners are needed. This study uses longitudinal data from 2014 (second year of middle school) to 2017 (second year of high school) of the Seoul Education Longitudibal Study, and divides it into groups with similar longitudinal patterns of change in mathematics academic achievement. The longitudinal change patterns and direct influence of mood and satisfaction were examined. As a result of the study, it was found that the mathematics academic achievement of the first group (1456 students, 68.3%) including the majority of students and the second group (677 students) of the top 31.7% had a direct influence on the mathematics class attitude. It was found that the mood and satisfaction of mathematics classes did not have a direct effect. In addition, the influence of mathematics class attitude on mathematics academic achievement was different according to the group. In addition, students in group 2 with high academic achievement in mathematics showed higher mathematics class attitude, mood, and satisfaction. In addition, the attitude, atmosphere, and satisfaction of mathematics classes were found to change continuously from the second year of middle school to the second year of high school, and the extent of the change was small.

A Study on Political Attitude Estimation of Korean OSN Users (온라인 소셜네트워크를 통한 한국인의 정치성향 예측 기법의 연구)

  • Wijaya, Muhammad Eka;Ahn, Heejune
    • Journal of Korea Society of Industrial Information Systems
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    • v.21 no.4
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    • pp.1-11
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    • 2016
  • Recently numerous studies are conducted to estimate the human personality from the online social activities. This paper develops a comprehensive model for political attitude estimation leveraging the Facebook Like information of the users. We designed a Facebook Crawler that efficiently collects data overcoming the difficulties in crawling Ajax enabled Facebook pages. We show that the category level selection can reduce the data analysis complexity utilizing the sparsity of the huge like-attitude matrix. In the Korean Facebook users' context, only 28 criteria (3% of the total) can estimate the political polarity of the user with high accuracy (AUC of 0.82).

A Study on the Structural Equation Modeling for the effect of e-Learning (대학생의 이러닝 학습효과 영향요인에 대한 구조방정식 모형 연구)

  • Heo, Gyun
    • Journal of Internet Computing and Services
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    • v.15 no.6
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    • pp.77-84
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    • 2014
  • The purpose of this study is to explore factors affecting the effect of e-learning, and to find out the casual relationship among these factors. Subjects are 2,091 students who have participated in e-learning based class during the period of second semester in 2013. Those of them, 1,732 students response to the survey questions. After gathering data, they are analyzed by using Confirmative Factor Analysis and Structural Equation Modeling. From the result of Confirmative Factor analysis, data have reduced four factors, and are named as four latent variables likes e-learning effect, contents satisfaction, managing assistant factor, and system functional factor. From the result of Structural Equation Modeling, it is known as the relation and impact among factors: (a) "managing assistant factor" affects to "contents satisfaction" directly. (b) "contents satisfaction" affects to "e-learning effect" directly. (c) "system function factor" affects directly to "contents satisfaction", but does not affect directly to "e-learning effect". (d) both "managing assistant factor" and "system function factor" have an indirect effect on "e-learning effect" via "contents satisfaction".

A Comparison Study on Satisfied Customer Reclassification Methods for Customer Satisfaction Management (고객만족경영을 위한 만족고객 재분류 방법의 비교 연구)

  • Song, Ki-Jeong;Seo, Kwang-Kyu
    • Journal of Digital Convergence
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    • v.11 no.1
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    • pp.139-144
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    • 2013
  • This paper is an exploratory study to improve customer satisfaction survey for resolving practical problems. It is natural phenomenon that, as the level of customer satisfaction index increases, the ratio of satisfied customers increases too. However, the effectiveness of practical application of customer satisfaction survey for improvement of customer satisfaction decreases due to its structural limitation on its data analysis system. In order to cope with these problems, we compares the three satisfied customer reclassification methods such as attribute complex scores, satisfaction/dissatisfaction dimension and latent class analysis models. The case study results show that satisfied customer reclassification methods have merits and demerits and are expected to play the role as the groundwork for the revitalization of customer satisfaction survey as well as improving customer satisfaction management.

A Study of the Relation of Stress to Oral Parafunctional Habits of Male High School Students (일부 지역 남자 고등학생들의 스트레스와 구강악습관과의 관련성 연구)

  • Jung, Yu Yeon;Hong, Jin Tae
    • Journal of dental hygiene science
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    • v.13 no.4
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    • pp.471-479
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    • 2013
  • This study is trying to grasp the stress of the male high school students and the correlation between the stress according to the academic and economic level and oral parafunctional habits, emphasizing the need for the education of oral parafunctional habits, providing the basic data in order to accomplish correctly until the oral health of the oral maxillofacial region. From May 2013 till July 2013, a self administered survey was conducted by the selected by convenience sampling from subjects of 1, 2 grade of two high school located in Chungnam, Korea. The study results were as follow: 1) Among five areas of stress, the stress of school life was the highest as 2.11 points and the stress of home problem was the lowest as 1.51 points; 2) the stress by class showed that grade 2 was higher than grade 1 in all areas. The stress of the school life (2.21) (p<0.01), interpersonal relationship (p<0.01), and own problem (p<0.05) showed the significant difference; 3) The significance analysis results between the five areas of stress according to the stress of latent variable and the oral parafunctional habits all showed the significant difference (p<0.001). The correlation between the stress and the oral parafunctional habits showed a weak negative correlation as -0.30, and the stress of the school life, own problem, environment problem, and interpersonal relationship showed very strong correlations more than 0.7; 4) Fit measures test result of stress, academic level, and family economic level model all showed more than 0.9 in good of fit index, adjusted goodness of fit index, normed fit index and root mean square residual and root mean square error of approximation values is all estimated less than 0.1, so it showed good model. From this study, it can be concluded that there is the correlation between stress and oral parafunctional habits.