• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.295-297
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• 2001

This paper deals with dynamic study of co-generator system with derived dynamic models of generator, excitation system, and turbine/governor from field tests. Mainly this study concentrates on frequency control of demand users that have co-generator by under-frequency relay. We simulates dynamic study of co-generator system using EMTDC.

• Journal of Intelligence and Information Systems
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• v.17 no.2
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• pp.39-60
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• 2011

Since the introduction of web 2.0 technology, social network service has been recognized as the foundation of an important future information technology. The advent of web 2.0 has led to the change of content creators. In the existing web, content creators are service providers, whereas they have changed into service users in the recent web. Users share experiences with other users improving contents quality, thereby it has increased the importance of social network. As a result, diverse forms of social network service have been emerged from relations and experiences of users. Social network is a network to construct and express social relations among people who share interests and activities. Today's social network service has not merely confined itself to showing user interactions, but it has also developed into a level in which content generation and evaluation are interacting with each other. As the volume of contents generated from social network service and the number of connections between users have drastically increased, the social network extraction method becomes more complicated. Consequently the following problems for the social network extraction arise. First problem lies in insufficiency of representational power of object in the social network. Second problem is incapability of expressional power in the diverse connections among users. Third problem is the difficulty of creating dynamic change in the social network due to change in user interests. And lastly, lack of method capable of integrating and processing data efficiently in the heterogeneous distributed computing environment. The first and last problems can be solved by using FOAF, a tool for describing ontology-based user profiles for construction of social network. However, solving second and third problems require a novel technology to reflect dynamic change of user interests and relations. In this paper, we propose a novel method to overcome the above problems of existing social network extraction method by applying FOAF (a tool for describing user profiles) and RSS (a literary web work publishing mechanism) to OLAP system in order to dynamically innovate and manage FOAF. We employed data interoperability which is an important characteristic of FOAF in this paper. Next we used RSS to reflect such changes as time flow and user interests. RSS, a tool for literary web work, provides standard vocabulary for distribution at web sites and contents in the form of RDF/XML. In this paper, we collect personal information and relations of users by utilizing FOAF. We also collect user contents by utilizing RSS. Finally, collected data is inserted into the database by star schema. The system we proposed in this paper generates OLAP cube using data in the database. 'Dynamic FOAF Management Algorithm' processes generated OLAP cube. Dynamic FOAF Management Algorithm consists of two functions: one is find_id_interest() and the other is find_relation (). Find_id_interest() is used to extract user interests during the input period, and find-relation() extracts users matching user interests. Finally, the proposed system reconstructs FOAF by reflecting extracted relationships and interests of users. For the justification of the suggested idea, we showed the implemented result together with its analysis. We used C# language and MS-SQL database, and input FOAF and RSS as data collected from livejournal.com. The implemented result shows that foaf : interest of users has reached an average of 19 percent increase for four weeks. In proportion to the increased foaf : interest change, the number of foaf : knows of users has grown an average of 9 percent for four weeks. As we use FOAF and RSS as basic data which have a wide support in web 2.0 and social network service, we have a definite advantage in utilizing user data distributed in the diverse web sites and services regardless of language and types of computer. By using suggested method in this paper, we can provide better services coping with the rapid change of user interests with the automatic application of FOAF.

• Journal of Digital Convergence
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• v.10 no.2
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• pp.171-182
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• 2012

The many companies and developers develop new mobile applications for serving to users. But, most of it is disappeared in a brief. Because Many applications weren't satisfy the needs of user. In this paper, it analysis to reason short life of mobile application in the smart terminals and mobile applications. Therefore, we develop dynamic user usability analysis system of applications to solve the problem. User usability analysis method is surveyed users and masters at present and then occurs high cost. In this paper, we develop dynamic user usability analysis system for real users. If usage of mobile applications upgrading, benefit of developers increased and serviced target contents to users.

• Korean System Dynamics Review
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• v.1 no.2
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• pp.149-174
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• 2000

In recent years, how to promore the Utilization of Internet is a main issue of national information policy. In this study, we focused our approach to find promoting sttategies for Internet utilization on three sector's users, governments, enterprises, and households. Promoting the Internet utilization of these three sector's users is a very difficult problem, because their information levels are different and information gap among them can be regarded as bottleneck. And since the interactions between user's demands and diverse information seccor's factors are very complex, policy leverages can not find easily. By the system dynamics methodology, this paper examines the interrelationships between three user's demand mechanism and information policy sector. Information policy sector consist of four sectors, infrastruccure policy seccor, application-contents sector, governance sector, and access and price policy sector (free access policy, literacy policy, telecommunication price policy, etc.). To find and investigate policy leverage that will help understanding dynamic behavior of users in using Internet we build a causal loop diagrams and SD models by using survey data obtained from three sectors'specialized users, 488 persons.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.4076-4092
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• 2019

Nowadays, most users access internet through mobile applications. The common way to authenticate users through websites forms is using passwords; while they are efficient procedures, they are subject to guessed or forgotten and many other problems. Additional multi modal authentication procedures are needed to improve the security. Behavioral authentication is a way to authenticate people based on their typing behavior. It is used as a second factor authentication technique beside the passwords that will strength the authentication effectively. Keystroke dynamic rhythm is one of these behavioral authentication methods. Keystroke dynamics relies on a combination of features that are extracted and processed from typing behavior of users on the touched screen and smart mobile users. This Research presents a novel analysis in the keystroke dynamic authentication field using two features categories: timing and no timing combined features. The proposed model achieved lower error rate of false acceptance rate with 0.1%, false rejection rate with 0.8%, and equal error rate with 0.45%. A comparison in the performance measures is also given for multiple datasets collected in purpose to this research.

• Journal of Korea Society of Digital Industry and Information Management
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• v.18 no.4
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• pp.77-83
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• 2022

As users' needs for customized services increase, the service provision method is changing from a vertical structural service provision method to a horizontal structural service provision method. This paradigm shift has led to a change from the way existing users find the content they want to find and provide customized needs of users by content providers. With the recent development of smartphones and various AI technologies, demand for providing seamless services such as smartphones is increasing in automobiles. However, it is difficult to provide services in line with changes in this service paradigm because automobile services provide services centered on finished car manufacturers rather than individually providing services tailored to user needs. In this paper, we develop a Node-RED-based dynamic vehicle service simulation tool so that users can use the service they want in cars. The simulation tool developed provides a simulation environment for services authored by the user using NodeRed by writing, registering, and using NodeRed.

• The Journal of Information Systems
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• v.30 no.4
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• pp.43-69
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• 2021

Purpose Although companies occupied the network market take the advantageous position first and can be successful in securing users over a certain size, it is important to satisfy the customers' demand and prevent the outflow of users toward a new alternative SNS. What is more, there are frequent changes in the flow of users toward new SNSs. Despite these dynamic market circumstances, there is a lack of research to explain the switching behaviors of SNS users. Design/methodology/approach The objective of this study is to explain and verify a specified migration theory(Push-Pull-Mooring model) focused on SNS fatigue in the psychological point of view, as well as reviewing previous studies on functional and technical characteristics of SNSs themselves. Moreover, this study tried to highlight factors affecting users actual SNS switch rather than their switching intention. Findings According to the statistical analysis, the most influenced pull factor to switch SNS was the alternative attractiveness. On the other hand, undesired relationship burden, service innovation and important mooring factors to prevent users' SNS switch. This study has a significant contribution to the theory, which analyzed users' actual SNS switch, and examined SNS users' psychological factors(SNS fatigue), reviewing the characteristics of existing services. To secure more users and to keep them, companies providing social network service need to develop differentiated strategies by analyzing psychological characteristics of various users.

• Journal of information and communication convergence engineering
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• v.1 no.2
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• pp.74-81
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• 2003

There are many researches on visual languages, but the most of them are difficult to support various collaborative interactions on a distributed multimedia environment. So, this paper suggests a collaborative visual language for interaction between multi-users. The visual language can describe a conceptual model for collaborative interactions between multi-users. Using the visual language, generated visual sentences consist of object icons and interaction operators. An object icon represents a user who is responsible for a collaborative activity, has dynamic attributes of a user, and supports flexible interaction between multi-users. An interaction operator represents an interactive relation between multi-users and supports various collaborative interactions. Merits of the visual language are as follows: supporting of both asynchronous interaction and synchronous interaction, supporting flexible interaction between multi-users according to participation or leave of users, supporting a user oriented modeling, etc. For example, an application to a workflow system for document approval is illustrated. So we could be found that the visual language shows a collaborative interaction.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.715-718
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• 2009

Time series data is a sequence of data points, measured typically at successive, spaced at time intervals. Many devices for an efficient exploration is developed according as the items of time series data increase. Among these devices, there is a Timebox widget as a representative device of dynamic query for interactive data exploration. Timeboxes are rectangular query region of interest. The users can draw the region of interest using simple mouse manipulation and the query result sets is displayed. But there is a limitation to represent the concrete query region and Timeboxes visualize the query region inconsistent with the mental model of users. To resolve these problems, we propose a new device called DQB(Dynamic Query Band). DQB is a qeury region consisting of user defined polyline with a thickness on time series data. This device is possible to concretely specify the query region. Also, it provides a simple and convenient interface and a good conceptual model.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.3
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• pp.109-122
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• 2020

In recent, projection mapping, which has attracted high attention in the field of realistic media, is regarded as a technology to increase the users' immersion. However, most existing methods perform projection mapping on static objects. In this paper, we developed a technology to track the movements of users and dynamically map the media contents to the users' bodies. The projected media content is built by predefined gestures just using the user's bare hands without the special devices. An interactive immersive media system has been implemented by integrating these dynamic projection mapping technologies and gesture-based drawing technologies. The proposed realistic media system recognizes the movements and open / closed states of the user 's hands, selects the functions necessary to draw a picture. The users can freely draw the picture by changing the color of the brush using the colors of any real objects. In addition, the user's drawing is dynamically projected on the user's body, allowing the user to design and wear his t-shirt in real-time.