• Journal of Internet of Things and Convergence
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• v.8 no.1
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• pp.37-43
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• 2022

The fundamental basis of AI technology is learningable data. Recently, the types and amounts of data collected and produced by the government or private companies are increasing exponentially, however, verified data that can be used for actual machine learning has not yet led to it. This study discusses the conditions that data actually can be used for machine learning should meet, and identifies factors that degrade data quality through case studies. To this end, two representative cases of developing a prediction model using public big data was selected, and data for actual problem solving was collected from the public data portal. Through this, there is a difference from the results of applying valid data screening criteria and post-processing. The ultimate purpose of this study is to argue the importance of data quality management that must be most fundamentally preceded before the development of machine learning technology, which is the core of artificial intelligence, and accumulating valid data.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.5
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• pp.1436-1446
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• 2015

This study aims to understand how scuba diving instructors' expertise, instructor reliability and instruction efficiency are related to each other. In order to achieve the research goal, the study used a multi-stage stratified cluster sampling method and collected valid samples from 400 individuals at age of 20 and older who were scuba diving in scuba diving clubs in Busan, Gyeongnam, Gyeongbuk, Jeonnam and Jeonbuk. The 400 valid samples were applied to the data analysis. The study used SPSS 21.0 for processing the gathered data via a frequency analysis, a reliability analysis and a correlation analysis and in order to verify the hypotheses, the study applied AMOS 21.0 and conducted a confirmatory factor analysis and a structure equation model analysis. Findings that the study had extracted are summarized as follows. First, the study confirmed that the scuba diving instructors' expertise has a positive effect on the instructor reliability. Second, the scuba diving instructors' expertise was reported to positively influence the instruction efficiency. Third, the results revealed that the scuba diving club members' reliability in the instructors has a positive influence on the instruction efficiency.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.2
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• pp.81-85
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• 1998

Location Registration and deregistration is necessary to mobility management in a Mobile Communication networks when a mobile phone moves between location registration areas. After considering several deregistration schemes, a sample scheme that eliminate network traffic is chosen. However, this scheme may delete valid registration record, so the size of location registration database must be sufficiently large to ensure low probability that a valid records are deleted. This paper describes an analytic model to determine the size of location registration database for a location registration area in this simple scheme. The simulation results of analytic model show that the size of database must 3-5 times than the expected number of mobile phones in a location registration area.(Mobile, Communications, Location, Deregistration, Database)

• The Journal of Information Systems
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• v.29 no.3
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• pp.77-101
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• 2020

Purpose Internet only bank is one of the promising untact businesses which are rising in COVID-19 pandemic. Kakaobank and Kbank have been offering banking services since 2017 in Korea and WeBank and MYbank in China opened the services since 2015. It is necessary to examining determinants of customer loyalty beyond intention to use. The purpose of the present study is to analyze factors influencing customer loyalty and their determinants. A research model integrating the relationships among customer loyalty, service satisfaction, trust, and social influence, and their determinants was proposed. Design/methodology/approach Structural equation modelling for validating the research model was employed. 235 valid data were collected from users of Internet only bank in China. Nine latent variables grouped from 38 indicators were reliable and valid and nine hypotheses were tested by using SmartPLS. Findings All nine hypotheses were supported at significant levels of 0.001 and 0.01. Trust, service satisfaction, and social influence had influenced on customer loyalty. Trust not only affected customer loyalty directly, but also had influence on it indirectly through service satisfaction. Empathy and convenience are determinants of trust. Perceived expertise and dispositions believing acquaints had a positive influence on social influence, whereas users' anxiety for technology or change had a negative influence on social influence. Implications for academics and practitioners were suggested.

• Wind and Structures
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• v.12 no.6
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• pp.541-551
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• 2009

This paper explains how to correctly measure the drag coefficient of a circular cylinder in wind tunnels with large blockage ratios and for the sub-critical to the super-critical flow regimes. When dealing with large blockage ratios, the drag has to be corrected for wall constraints. Different formulations for correcting blockage effect are compared for each flow regime based on drag measurements of smooth circular cylinders performed in a wind tunnel for three different blockage ratios. None of the correction model known in the literature is valid for all the flow regimes. To optimize the correction and reduce the scatter of the results, different correction models should be combined depending on the flow regime. In the sub-critical regime, the best results are obtained using Allen and Vincenti's formula or Maskell's theory with ${\varepsilon}$=0.96. In the super-critical regime, one should prefer using Glauert's formula with G=0.6 or the model of Modi and El-Sherbiny. The change in the formulations appears at the flow transition with a variation of the wake pattern when passing from sub-critical to super-critical flow regimes. This parameter being not considered in the known blockage corrections, these theories are not valid for all the flow regimes.

• Journal of the Korean Society for Library and Information Science
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• v.36 no.3
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• pp.259-274
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• 2002

Recently, a great deal of corporations have adopted knowledge management system with eagerness to enhance the company competitiveness. However, since the main feature of knowledge management system is not just a simple information system but another entity creating intangible assets tailed "knowledge", we need to develop a new approach to investigating the performance and acceptance of knowledge management systems from a perspective allowing knowledge-sensitive constructs. In this regard, we develop new constructs like knowledge schema and several knowledge circulation-related activities. As a research model, we adopt a famous technology acceptance model or TAM by Davis (1989), and extend it into incorporating knowledge schema. With the statistically valid and usable questionnaire survey data collected from 886 respondents in a big corporation typically using knowledge management system, we induced a robust result empirically, saying that knowledge schema and knowledge circulation activities are valid determinants of performance and acceptance of knowledge management systems.

• Korean Journal of Logic
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• v.8 no.1
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• pp.47-67
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• 2005

Bayesian networks have been used in studying and simulating causal inferences by using the probability function distributed over the variables consisting of inquiry space. The focus of the debates concerning Bayesian networks is the causal Markov condition that constrains the probabilistic independence between all the variables which are not in the causal relations. Cartwright, a strong critic about the Bayesian network theory, argues that the causal Markov condition cannot hold in indeterministic systems, so it cannot be a valid principle for causal inferences. The purpose of the paper is to explore whether her argument on the causal Markov condition is valid. Mainly, I shall argue that it is possible for upholders of the causal Markov condition to respond properly the criticism of Cartwright through the continuous causal model that permits the infinite sequence of causal events.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.2
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• pp.53-58
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• 2020

Analysis of electric semiconductor packaging technology for electric vehicles was performed. Topic modeling using LDA technique was performed by collecting valid patents by deriving valid patents. It was classified into 20 topics, and the definition of technology was defined through extracted words for each topic. In order to analyze the trend of each topic, the trend of power semiconductor packaging technology was analyzed by deriving hot and cold topics by topic through regression analysis on frequency by year. The package structure technology according to the withstand voltage, the input/output-related control technology and the heat dissipation technology were derived as the hot topic technology, and the inductance reduction technology was derived as the cold topic technology.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.207-209
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• 1991

This paper deals with voltage control method of PWM rectifier using current-controlled voltage type converter. A linearized model of the current-controlled rectifier is derived, which is used to examine the effect of controller gains to its dynamic responses. Through the simulation, it is shown that the proposed model is generally valid, which is confirmed by experimental results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.161-166
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• 2001

The static characteristics of four-nozzle flapper valves are investigated with both constant flow and constant supply pressure. The ranges, in which linearization of these characteristics would be valid, are discussed. Linearized dynamic model is also derived. Numerical simulations of nonlinear dynamic model are carried out by HyPneu to make an assessment of the effect of input step size in both cases of no-load and blocked-load operation.