• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.4
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• pp.163-181
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• 2004

Group key agreement protocols are designed to solve the fundamental problem of securely establishing a session key among a group of parties communicating over a public channel. Although a number of protocols have been proposed to solve this problem over the years, they are not well suited for a high-delay wide area network; their communication overhead is significant in terms of the number of communication rounds or the number of exchanged messages, both of which are recognized as the dominant factors that slow down group key agreement over a networking environment with high communication latency. In this paper we present a communication-efficient group key agreement protocol and prove its security in the random oracle model under the factoring assumption. The proposed protocol provides perfect forward secrecy and requires only a constant number of communication rounds for my of group rekeying operations, while achieving optimal message complexity.

• Journal of Internet Computing and Services
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• v.12 no.4
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• pp.181-194
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• 2011

Server push which is technology of sending contents from servers to browsers in real time using long polling requests enables real time bidirectional communications between servers and browsers in HTTP environment. Recently, thanks to the rapid supply of mobile devices having ability of full browsing, server push is being applied to various applications. However, because servers providing services should offer distributed contents to a large number of users simultaneously in various user environments, they have a burden that offers contents quickly distinguishing much more concurrent users than before. The method of message exchange so far achieved in distributed server environment has difficulties in the performance of simultaneous user request process, the identification of users and the contents delivery. In this paper, We proposed message exchange architecture between servers for offering server push in the distributed server environment. The proposed architecture enables message exchange in the method of push between servers based on event driven architecture. In addition, the proposed architecture enables flexible identification of a event agent and event processing under the connected environment of a lot of users. In this paper, we designed and implemented the proposed architecture and compared performance with the previous way through a performance test. In addition, function is confirmed through the case realization. As a result of the performance test, the proposed architecture can lessen the use of server Thread and response time of users and increase simultaneous throughput.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.1
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• pp.72-85
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• 2012

Today, although most bluetooth hands-free devices within a vehicle provide telephone service functions such as voice communication, caller id display and SMS message display and so on, they do not provide a function that displays Internet-based text data. We need to develop a scheme that displays the internet-based text data including existing hands-free function because the request for using the Internet service is increasing within a vehicle recently. The proposed bluetooth device application includes advanced function such as SNS message arrival notification, the message display function and we chose Android as the implementation mobile platform giving consideration to the fact that most SNS applications operate on Android and the platform is easily embedded into small embedded device. Smartphone or tablet PC connected with the proposed bluetooth device is an Android-based device and we designed a form of Android app for the function implementation of the devices. When the audio-text gateway app receives SNS text data, it extracts title and sender information from the message header information in a form of text data and sends them via ACL (Asynchronous Connection-Oriented) link to the bluetooth device showing the data on the screen. Android-based bluetooth devices are not possible to play voice through speaker because the bluetooth hands-free or headset profile ported within Android platform normally only includes audio gateway's function. The proposed bluetooth device application, therefore, applies the streaming scheme that sends data via ACL link instead of the way that sending them via SCO (Synchronous Connection-Oriented) link.

• Journal of the HCI Society of Korea
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• v.6 no.2
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• pp.1-9
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• 2011

Increasing communication through social media forming impression becomes more important. In this research, how three stimulus can build the impression of Twitter Account Owner(TAO) such as the types of the profile pictures, the types of timeline messages and the number of followers. We analysed the feelings of respondents when they face TAO's formal picture and informal picture, informative message and normal message, the number of followers. We, in addition, measured the willingness of respondents whether they want to develop their relationship online and offline as well. As a result, informative message draws positive reliability and makes respondent want to build deeper relationship with TAO at online. Respondent answered TAO's informal picture was more likable than formal picture and more reliable when informative message and formal picture were provided together. Our study shows that there are actual differences at attitudes of respondents by the types of the profile pictures and the types of timeline messages. Thus, we can conclude that TAOs can modify their impressions at online as they hope to.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.9
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• pp.211-216
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• 2016

Worldwide casualties caused by earthquakes, floods, fire or other disaster has been increasing. So many researchers are being actively done technical studies to ensure golden-time. In this paper if a disaster occurs, use the IoT technologies in order to secure golden-time and transmits the message after to find the user of the accident area first. When the previous job is finished, gradually finds a user of the surrounding area and transmits the message. For national emergency information, OPEN API of Korea Meteorological Administration was used. To collect detailed information on a relevant area in real time, this study established the system that connects and integrates Crowd Sensing technology with BLE (Bluetooth Low Energy) Beacon technology. Up to now, the CBS based on base station has been applied. However, this study designed and mapped DB in the integration of Beacon based user positioning and national administrative address system in order to estimate local users. In this experiment, the accuracy and speed of information dif6fusion algorithm were measured with a rise in the number of users. The experiments were conducted in a manner that increases the number of users by one thousand and was measured the accuracy and speed of the message spread transfer algorithm. Finally, became operational in less than one second in 20,000 users, it was confirmed that the notification message is sent.

• Korean Journal of Communication Studies
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• v.18 no.1
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• pp.195-222
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• 2010

This study is aimed at examining the degree in message recognitions with respect to the same global brand Ad. campaign intended for local consumers in Korea, China, and United-States, and applying the results to the forseeable message production of global Ad. campaigns. For this purpose, we conducted a survey by providing those consumers with Anycall Ads. of Samsung mobile phones, which were inserted in local printed advertisements. We concluded that the cultural and environmental differences of markets represent different degrees in message recognitions among these three countries. This result suggests that the localization based on local cultures and market situations is more important than the general standardization in the future global brand Ad. campaigns.

• Journal of Christian Education in Korea
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• v.66
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• pp.113-145
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• 2021

As a contemporary exponent of Bauderillard's Simulation and Simulacra, this paper aims to reflect on the 'consumer culture' criticized by Baudrillard from the lens of Christian Education in reading the Drama, Penthouse related to the notions of the consumption-ideology, the desire and violence of image in the post-Covid 19 era. As Baudrillard begins to realize that the concept of simulation rooted from mass media in the modern society, he explains mass media as the emerging of Simulation or the process of Simulation will lead to the impulsion of reality, which ends up with vanishing the original reality. Baudrillard is explaining in his argument that the process of Simulation proceeds among various areas of the contemporary society being manipulated by mass media. While Simulation is the process of producing the hyperreality characterized by the excess of images that seems more real than the original reality, Simulation brought about Simulacra as excess reality or consequently exploding reality. Christian educators in the post-Covid 19 must know how to deal with critical theory by considering positive ways of avoiding questioning of how to articulate what the norm of universal consensus is in the specific situation. In other words, it should be noted that the nature of the ruling ideology and the ideology of consumption has been influenced or manipulated by mass media. Christian educators especially have to help young people in seeing the messages from the images of the screens, television, soap-opera, and commercial advertising making reality as Simulacre which is more real than the original reality. When the medium becomes the message, the power of medium makes the consumer not reach communication with it. This is the main reason in the controversy about the images on television drama, Penthouse and the impact of images on people's mind. As an exponent of McLuhan's belief that "the medium is the message", Baudrillard argues although the message and a subject of Simulacra(excessive reality) is unexpectedly disappearing, the medium itself is vanished through the silence of image. However, the task of Christian education has to fuel how we teach, learn, share and pass on the Word of God as the Message. Furthermore, it is worth noting that the Message of God cannot be vanished or burst with the impulsion of it, but exists forever. With Baudrillard's ideas of Simulation and Simulacra in mind, the work of Christian education as an observation platform can better engage the reflection on a consumer society of consumerism that makes Church community and a consumer irresistible against the Fake world.

• Journal of Distribution Science
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• v.14 no.6
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• pp.89-98
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• 2016

Purpose - This article tackles risk communication issues and aims to address the characteristics of MERS risk information distribution in South Korea, and secondly to examine the communicative behavior of the public health authority in terms of the quality of communication strategies. Thirdly, the study attempts to figure out the risk communication to cope with MERS through the applications of SMCRE model in chronological order. We employ the social amplification of risk framework for analyzing the emergent public response as one of the main approaches. Research Design, Data and Methodology - The main framework of this study is theoretically based on the social amplification of risk, which describes signals about risk transmitted and processed by individuals and social groups. The model also reflects the interactions between social groups and institutes about disaster-related risk issues, which are potential amplifiers or attenuators of communication signals. S-M-C-R-E Model is methodologically employed to examine the social amplification for MERS risk information in each period, which we defined operationally. The proposed methodology allows the assessment of effectiveness and ineffectiveness on risk communication to be conceptualized as a countermeasure against disasters. The paper focuses on exploring how social risk amplification can be applied and organized in each stage. Results - The SMCRE model describes the exchange of risk information and is also applied to all forms of communication between stakeholders including public health authority, local government and media. Each factor of risk communication includes source, message, channel, receiver and effect. The results support that the effective risk communication involves not only the improved reliability of public health authority as a key factor of risk communication, but also a close cooperation and good collaboration with local governments. It does not seem to be possible that the government-initiated risk communication based on controllability and management cope effectively with infectious disease in early stage. The results of this study imply that the shared risks between local, regional and national authorities can enhance risk communication system. Conclusions - The study supports that the disparities in how disaster-related risk information is interpreted and coded, have made effective risk communication and public sense-making impeded. Our findings support a more communicative discussion about the role of risk information sharing between governments for the improvement of emergency management and underline the importance of social elements in the risk communication, such as relationship and trust building. Findings suggest that trust building between stakeholders could be added to help explain the processes of social amplification and attenuation of risk. It would be recommended that the continuous risk communication with all the involved stakeholders will be able to help national health promotion policy to be improved regarding emergency management. Furthermore, risk communication has to be a scientific approach for the communication pertaining to potentially sensitive or controversial situations with public concerns and low public trust.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.421-427
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• 2009

This paper has proposed 1-2-1 coded cooperative communication that is a combination of STBC and ARQ. Coded cooperative communication is a protocol that integrates channel coding with cooperative communication. In this paper consider convolution encoder. ARQ method can increase the spectral efficiency than conventional cooperative communication because if the received signal from source node is satisfied by the destination preferentially, the destination transmits ACK message to both relay node and source node and then recovers the received signal. Where each relay 1, 2 forwards a punctured portion of receive data. When relay transmit to destination apply STBC the reliability to increase. Moreover this protocol can get better BER performance of receiver using simple comparator. We verified BER performance for the proposed protocol through Monte-Carlo simulation over Rayleigh fading plus AWGN.

• Journal of Advanced Navigation Technology
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• v.24 no.2
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• pp.67-72
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• 2020

Satellite communication is not used by many people like mobile communication, but it is a necessary technology for public service and communication services, such as providing the Internet in military, disaster, remote education and medical services, island areas, and infrastructure vulnerable areas. However, on ships and aircraft, mobile communications requiring base stations are either unavailable or restricted in their use. In this paper, we used a Raspberry Pi board as the terminal device to communicate network through satellite modem and PPP protocol, and implemented two-way data link using the text message of the modem to connect to the Thuraya geo-stationary orbit network. In addition, I/O devices were connected to the controller of the terminal equipment to design and implement an IoT device system for ships that can remotely access the system under control and control I/Os and transmit measured data through various sensors.