• Information Systems Review
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• v.23 no.3
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• pp.159-176
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• 2021

Obviating user churn is a prominent strategy to capitalize on online games, eluding the initial investments required for the development of another. Extant literature has examined factors that may induce user churn, mainly from perspectives of motives to play and game as a virtual society. However, such works largely dismiss the service aspects of online games. Dissatisfaction of user needs constitutes a crucial aspect for user churn, especially with online services where users expect a continuous improvement in service quality via software updates. Hence, we examine the relationship between a game's quality management and its user base. With text mining and survival analysis, we identify complaint factors that act as key predictors of user churn. Additionally, we find that enjoyment-related factors are greater threats to user base than usability-related ones. Furthermore, subsequent quasi-experiment shows that improvements in the complaint factors (i.e., via game patches) curb churn and foster user retention. Our results shed light on the responsive role of developers in retaining the user base of online games. Moreover, we provide practical insights for game operators, i.e., to identify and prioritize more perilous complaint factors in planning successive game patches.

• The Journal of the Korea Contents Association
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• v.20 no.6
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• pp.197-210
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• 2020

Learning agility is the will and ability to flexibly change thoughts and behaviors by quickly learning in new environments and experiences, and is a core competency to overcome crisis and solve organizational problems. It is a concept that can be used in the same organization group. Based on the previous research, a study was conducted to investigate how the job characteristics and personal learning agility of the army deputy officers influence learning satisfaction. After receiving a questionnaire survey of 216 business and yarn companies, SPSS 24.0 was used to verify the reliability and validity of the measurement variables, and the hypothesis was verified by regression analysis. It was found that some of the sub-categories of personal learning agility (self-awareness, active change pursuit) had a positive effect on learning satisfaction. This means that in order to enhance the effectiveness of military cyber education, measures should be taken to avoid overload in the field, and in order to increase performance in military organizations, personal learning agility pursuing positive change based on self-awareness and feedback must be developed.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.3
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• pp.240-245
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• 2004

This paper presents a Switched Reluctance Motor(SRM) drive using the self-tuning control method to achieve the maximum torque. SRM has the difficulty to research it by an analytic method and to control the speed End torque because of the high nonlinearity. So, in this paper, the self-tuning control method is applied to relevantly controlling turn-on/off angle to operate at the maximum torque. Also, the feedback signals to control the turn-on/off angle are the encoder pulse and the increment of phase current. At first, n adequate turn-off angle is searched by itself and then a turn-on angle is done. As the relationship between turn-on and him-off angle is mutual dependent, the turn-on/off angle is controlled by a real time self-tuning control method in order to maintain the maximum torque. The proposed self-tuning Algorithm is verified by experiments.

• The Journal of Korean Society for School & Community Health Education
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• v.18 no.1
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• pp.99-110
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• 2017

Objectives: The purpose of this study was to examine the effect of the field practice of health science majors on their career attitude maturity in our country in an effort to determine influential factors. Methods: The subjects in this study were 220 selected health science majors in three different colleges located in North Gyeongsang Province and South Chungcheong Province. A survey was conducted with structured questionnaires from September 1 to 10, 2016. As for statistical analysis. a statistical package SPSS 20.0 was used. Results: The factors of the field practice of the health science majors that affected their career attitude maturity were the career of people in charge(${\beta}=.145$, p-.034) and the content of field practice(${\beta}=.233$, p=.015), which were the factors of the institution for field practice, and the relationship between people in charge and trainees(${\beta}=.299$, p=.008) and satisfaction with field placement(${\beta}=-.262$, p=.013) that were the factors of field practice tasks were also influential. The influence of these factors were statistically significant. Conclusions: Institutions that provide health science majors with the opportunity of field practice should try to improve the competencies of people in charge, to ensure the substantiality of field practice in content and to develop standardized manuals for field practice. In schools, professors who are in charge of field practice should offer intensive guidance and feedback on problems with field practice. These efforts are expected to elevate the career attitude maturity of students.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.42-50
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• 2011

Using EEG, human physiological signal, as part of research which investigates the state of student learning and provides appropriate feedback to maximize learning efficiency, the relationship of learning attitude and analysis of EEG for female college student is presented. We study the reaction of learner's EEG using the concentration level extracted from the EEG power spectrum when students learn at various learning attitude. The experiment was conducted for the concentrating on learning and, as a control group, erratic attitude and closed eyes state. The attitude of concentrated Learning shows high concentration index and low relaxation index, where as the erratic attitude, such as eye movement and clicking, shows high level of attention index and noisy wave ratio. Especially, the state of closed eyes shows the ratio of alpha and theta wave under 1. This is distinct with open eyes cases.

• Korean Institute of Interior Design Journal
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• v.27 no.1
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• pp.156-164
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• 2018

This study analyzed the characteristics of Physical Environment of existing free shuttle bus Interior centered on elderly people who frequently use free shuttle buses. The purpose of this study is to provide basic data that can be used for improvement of existing free shuttle buses. In the case of the old type, in terms of accessible design, the middle entrance is not normally opened except the wheelchair occupant, so that the entrance of the front wheel is always used. Therefore, most elderly people go to the back seat and travel distance is twice longer. In addition, many stairs caused frequent inconveniences for boarding. In the case of the new type, it is planned to be a low-floor type, and various types of safety rods and handles, pictograms for enhancing the information convenience are well-equipped, and the measured value of the overall design characteristic is high. However, in the case of mental stability, it was confirmed that the seat of the bus is colored with a cold color system and is in a different relationship with the warm color which can feel mental stability. Overall, both old and new shuttle buses lack audiovisual feedback on bus routes and route guidance in terms of Supportive design. Also, since the cleaning tools and other miscellaneous items were left in the room, it became an obstacle to space utilization in terms of adaptable design. In terms of safety, both shuttle buses did not come into view with fire extinguishers shaded by miscellaneous items. Therefore, immediate action is unlikely in case of emergency. This problem should be resolved quickly.

• Journal of Biomedical Engineering Research
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• v.29 no.4
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• pp.323-328
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• 2008

A patient with respiratory disorders such as a sleep apnea is increasing as the obese patient increase on the modern society. Positive Airway Pressure (PAP) devices are used in curing patient with respiratory disorders and turn out to be efficacious for patients of 75%. However, these devices are required for evaluating their performance to improve their performance by the mechanical breathing simulator. Recently, the mechanical breathing simulator was studied by the real time feedback control. However, the mechanical breathing simulator by an open loop control was specially required in order to analyze the effect of flow rate and pressure after operating the breathing auxiliary devices. Therefore the aims of this study were to make the mechanical breathing simulator by a piston motion and a valve function from the characteristic test of valve and motor, and to duplicate the flow rate and pressure profiles of some breathing patterns: normal and three disorder patterns. The mechanical simulator is composed cylinder, valve, ball screw and the motor. Also, the characteristic test of the motor and the valve were accomplished in order to define the relationship between the characteristics of simulator and the breathing profiles. Then, the flow rate and pressure profile of human breathing patterns were duplicated by the control of motor and valve. The result showed that the simulator reasonably duplicated the characteristics of human patterns: normal, obstructive sleep apnea (OSA), mild hypopnea with snore and mouth expiration patterns. However, we need to improve this simulator in detail and to validate this method for other patterns.

• Journal of Intelligence and Information Systems
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• v.17 no.4
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• pp.1-17
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• 2011

In order to maintain customer satisfaction and to remain productive and efficient in today's global competition, mass customization is adopted in many leading companies. Mass customization through product family and product platform enables companies to develop new products with flexibility, efficiency and quick responsiveness. Thus, product family strategy based on product platform is well suited to realize the mass customization. Product family is defined as a group of related products that share common features, components, and subsystems; and satisfy a variety of market niches. The objective is to propose a product family design strategy that provides priority weights among product components by satisfying customer requirements. The decision making process for a new product development requires a multiple criteria decision making technique with feedback. An analytical network process is adopted for the decision making modeling and procedure. For the implementation, a netbook product known as a small PC which is appropriate for the product family model is adopted. According to the proposed architecture, the priority weight of each component for each product family is derived. The relationship between the customer requirement and product component is analyzed and evaluated using QFD model.

• Journal of The Korean Association of Information Education
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• v.21 no.6
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• pp.691-699
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• 2017

Along with the increased significance of SW education in the 2015 revision curriculum, SW education using various educational methods and tools is being performed, and teaching and learning contents using SW education tools are continuously being developed. In this paper, we analyzed pre-service teachers' EPL contents preference types, preferred development subjects, and their relationship with pre-service teachers based on the analysis conducted after their EPL class session in which its results were assortatively analyzed by department, letter grade, and type. The result signified a clear difference in development subject and types among the departments, and it also showed a difference in development subject and its recipients among the types. However, there was no difference between development subject and type among the letter grade. This will provide a feedback on EPL classes and help develop EPL-related curricula as well as its application.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.10
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• pp.5161-5165
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• 2012

Background: There are few molecular markers known to predict cholangiocarcinoma (CCA) prognosis. Smad7 has a certain relationship with epithelial-mesenchymal transition (EMT), but its relevance to CCA in unclear. Therefore expression and clinical significance of Smad7 in CCA was the focus of this study. Methods: Expression of Smad7, E-cadherin and vimentin was assessed in 41 patients with CCA by immunohistochemistry and analyzed for associations with clinical parameters. Results: Smad7 and vimentin expression in the CCA tissue was dramatically higher than that in adjacent tissues. In addition, Smad7, vimentin and E-cadherin expression was significantly associated with CCA lymph node metastasis and perineural invasion($P{\leq}0.05$), but not other factors, such as gender, age, tumor location, tumor type and tumor differentiation degree (P>0.05). The overall survival and relapse-free survival rate was significantly higher in patients with negative Smad7 expression than those with positive Smad7 expression. Conclusion: EMT phenomena may occur in the process of CCA invasion and metastasis. Smad7, which was highly expressed in CCA, may be considered to be one feedback regulator in late stages and could have potential as a prognostic indicator for clinical assessment.