• Journal of the Korean Society of Radiology
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• v.4 no.3
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• pp.31-37
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• 2010

In this paper, a photovoltaic system is designed with PWM(Pulse Width Modulation) voltage source inverter. Proposed synchronous signal and control signal was processed by 56F8323 microprocessor for stable modulation. The PWM voltage source inverter using inverter consists of complex type of electric power converter to compensate for the defect, that is solar cell cannot be developed continuously by connecting with the source of electric power for ordinary use. It can cause the effect of saving electric power, from 10 to 20[%]. The PWM voltage source inverter operates in situation that its output voltage is in same phase with the utility voltage. In addition, I connected extra power to the system through operation the system voltage and inverter power in a synchronized way by extracting the system voltage so that the phase of the system and PWM voltage inverter can be synchronized. In the system of this research showed good results after being controlled in order to provide stable power to the load and the system through maintaining and low output power of harmonics.

• Journal of Industrial Convergence
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• v.17 no.4
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• pp.87-94
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• 2019

The purpose of this study is to predict the usefulness and predictable effects of the use of dementia prevention games and dementia management applications provided in smart-phones for the elderly. First, 6 dementia diagnostic tools used to verify the effectiveness of the dementia prevention program were selected and the cognitive domains tested by each diagnostic tool were extracted. Second, 29 smart-phone dementia prevention game applications and dementia management applications were selected and the expected effects after using these applications were analyzed in connection with the cognitive domain extracted from the dementia diagnosis tool. As a result, it was expected that it would be helpful to manage dementia prevention by improving cognitive function in certain areas when playing games or managing dementia continuously using smart-phone dementia prevention applications. Smart-phone dementia prevention applications will be useful in improving the cognitive ability of the elderly and preventing dementia by supplementing the limitations of the dementia prevention program that is operated offline through time-space ease of use, continuous usability and economic feasibility.

• The Journal of Korean Association of Computer Education
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• v.10 no.3
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• pp.19-29
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• 2007

The informationization policies undertaken in concentration only on the national economic growth invited the unbalance between technology and social culture, displayed the serious reverse function phenomena, and these problems threatened the personal identity of individual in the cyber space. In this study, we developed an index model on the information and communication ethics where the national level of information and communication ethics can be examined. For this purpose, based on diverse previous research data, the areas of the ethical indicators in information and communication has been developed through the brain storming of the research staff. Through the consultation with experts, the feasibility and representation as index was heightened, and the weighted values to the each index was provided by the AHP method. The outcome of questionnaires from the information users and information providers (great portals) was also reflected in simple average method into the calculation of the weighted value to the each index element.

• Korean journal of communication and information
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• v.23
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• pp.47-77
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• 2003

Despite the near ubiquity of mobile phone and internet, the 'meta research' that deals with face-to-face(FTF), mobile phone and internet together as interpersonal media is very rare in Korea. This study begin with the purpose of fair repositioning of mobile phone and internet in Korean's interpersonal communication horizon. To accomplish this purpose, We examined the effect of face-to-face communication situation on uses of mobile phone and internet as interpersonal communication media. The related raw data were collected from on-line survey process, and statistically analyzed. The result showed that persons who are more troublesome in FTF communication because of their timidness or personality problem are more restricted in human communication network via mobile phone and internet than the others who are not. And more 'addicted' in internet use and more active in trying another personality(Persona) in cyber space. And more shrunk in meeting and conversation with family members and friends after internet adoption.

• Journal of Distribution Science
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• v.7 no.1
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• pp.71-90
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• 2009

Recently, highway service becomes a very important service in highways. Highway service is considered as a positive interaction method between highway service companies and customers. From this perspective, this study was to investigate the relationships between influencing factors of highway service and user satisfaction. And, this research was to examine the differences between importance and performance of highway service factors using IPA (Importance-Performance Analysis). The result of this study has categorised the 22 highway service attributes into seven highway service selection factors: food, culture, kindness and health, products, large space, employee and Phone, facility. Using IPA, this study has compared the importance and performance of highway service selection factors, as perceived highway service customers. The empirical findings suggest that strategic framework using IPA gives guidelines that improve effectiveness of highway service.

• Journal of The Korean Association of Information Education
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• v.8 no.2
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• pp.167-176
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• 2004

Due to the development of information communication technology, educational environment has undergone much change and various types of teaching and learning methods based on information communication technology has been suggested. Recently, remote education using the internet are also spreading. However, in current classrooms, students are asked to do an teacher-centered assignment, which they are required to collect and report some information using the internet. This method does not help students use the advantages of learning using the internet, which stimulate students-students interaction and teacher-students interaction.Thus, this study focused on the problem-based learning system based on video communication technology. The researcher designed the problem-based learning system based on video communication technology and applied the system to classes at elementary school. The results were analyzed in terms of students-students interaction and teacher-students interaction in the internet. This research found that the problem-based learning system stimulates teacher and students communication and has positive effects on students' attitude and interest in learning. This research proposes that the traditional teacher-centered teaching method can be supplemented with cyber space learning, which has the merit of problem-based learning model.

• Korean Journal of Human Ecology
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• v.18 no.2
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• pp.381-395
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• 2009

This study was conducted to investigate effects of self concept of children consumers on consumption propensity of online items according to gender by considering that self, which means a thought on ownself, is expressed as online items in cyber space. Totally, 760 copies of the questionnaire were distributed and 716 ones were finally used as data for analysis in this study. The data were analyzed by using SPSS 14.0 and factorial analysis, Cronbach' ${\alpha}$, t-test, cross tabulation analysis and multiple regression were conducted. The results of this study could be summarized as follows. First, the factorial analysis performed to examine types of self concept found four factorial structures - justness, social, academic and family self. In addition, the factorial analysis done to determine compositional factors of irrational consumption propensity of children consumers showed three factorial structures - impulse buying, conspicuous consumption and imitative consumption. When the effects of personal variables, item-transaction variables and self concept on irrational consumption propensity of children consumers were investigated according to gender, significant factors affecting consumption propensity of both of the males and females were a monthly pocket money, time using the Internet and major transaction items. In addition, parents' permission for purchasing items, justness self and family self were found to be variables affecting consumption propensity in the male children. On the contrary, self concept of female children did not affect irrational consumption propensity.

• Journal of KIISE
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• v.45 no.3
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• pp.294-302
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• 2018

With the emergence of the new service industry due to the development of information and communication technology, cyber space risks such as personal information infringement and industrial confidentiality leakage have diversified, and the security problem has emerged as a critical issue. In this paper, we propose a behavior-based anomaly detection method that is suitable for real-time and large-volume data analysis technology. We show that the proposed detection method is superior to existing signature security countermeasures that are based on large-capacity user log data according to in-company personal information abuse and internal information leakage. As the proposed behavior-based anomaly detection method requires a technique for processing large amounts of data, a real-time search engine is used, called Elasticsearch, which is based on an inverted index. In addition, statistical based frequency analysis and preprocessing were performed for data analysis, and the DBSCAN algorithm, which is a density based clustering method, was applied to classify abnormal data with an example for easy analysis through visualization. Unlike the existing anomaly detection system, the proposed behavior-based anomaly detection technique is promising as it enables anomaly detection analysis without the need to set the threshold value separately, and was proposed from a statistical perspective.

• Journal of Engineering Education Research
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• v.6 no.1
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• pp.5-14
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• 2003

This paper presents a simplified web-based simulator for digital logic circuits with which several important principles related to digital logic circuits can be understood and confirmed. The proposed simulator is implemented to have several simplified functions which are essential to the learning process of digital logic circuits. The learners by themselves simulate several digital logic circuits on the web under specific input conditions and the design/analysis of digital logic circuits can be available. The proposed simulator, combined with multimedia contents, can be used as an auxiliary educational tool and enhance the improved learning efficiency. The results of this paper can be widely used to improve the efficiency of web-based educations in the cyber space. Several simulation results are illustrated as examples to show the validity of the proposed web-based simulator.

• Journal of the Korean housing association
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• v.19 no.1
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• pp.57-66
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• 2008

In the past, strong social bands, which had spontaneous communities, existed in Korean traditional society. However, while it's developing through industrialization; monolithic apartment houses were introduced which causes less interaction between neighbors. With the growing attention to the higher living quality, various schemes to revitalize the community spirits have been groped, including to improve in hardhearted neighborhood relationships and to cope with the dreariness in the city. With the development of the internet and the spread of 'digital home', the communities in cyber space have been especially revitalized since the information-oriented society. In a move to strengthen the communities in apartment complexes, this study tries to find the revitalization scheme for virtual communities in apartment complexes by analyzing the contents of its web sites and understanding the world of virtual community. These are compared and analyzed. The related virtual communities ("cafe" or "blogs") are also analyzed. The results are as follows. 1) There are some differences among the contents provided by apartment virtual community developing companies, still, it could be categorized into four types; "apartment complex introduction and management information" "community revitalization" "living guide" "individual services" 2) The contents provided by self-organized communities of residents neither require additional charge nor special membership for information while the formation is not systematized. 3) In the comparison of apartment virtual community developing companies with residents self-organized communities, "apartment complex introduction and management information" on freeboard, notice, request and Q&A, and "community revitalization" on communication board are both provided throughout the web sites. 4) The contents provided by apartment virtual community developing companies makes the information available in a wide range with managers, on the other hand, self-organized communities emphasize on showing attachment and concern of residents and requiring communications between neighborhoods.