• Journal of Digital Convergence
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• v.17 no.1
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• pp.301-311
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• 2019

Digital convergence put a huge challenges for broadcast media in terms of integrating user generated content (UGC). Keeping this in mind, objective of the study is to explore the factors that affecting UGC's integration in Broadcast channel from developing countries' perspective. We explored how and why UGC are appearing in Bangladeshi Television news. In-depth interview was used and news editorial level staffs were selected from leading Bangladeshi television channels. Findings suggest that, state interventions in crisis events and lack of experiences to handle crisis reporting played a crucial role to incorporate UGC in television news bulletins. One of the significant findings is that, mere traditional guidelines and work policy of the media houses will not be enough to handle user generated content as well as citizen's participation in news media. Thus, we recommend to formulate a comprehensive user generated content integration policy in the context of Bangladesh.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.6
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• pp.69-78
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• 2004

During the last decade, security models have been defined for two- and three-parity key exchange protocols. Currently there is a growing research interest in security models for group key management schemes. While various security models and provably secure protocols have been proposed for distributed group key exchange schemes, no results are hewn for centralized group key distribution schemes in spite of their theoretical and practical importance. We describe security requirements and a formal security model for centralized group key distribution scheme: we define the model on the channel controlled by adversaries with the ability of strong user corruption. In the security model, we propose a conversion module which can transform centralized tree-based group key distribution schemes in the literature to provably secure centralized tree-based group key distribution schemes.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.6
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• pp.93-112
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• 2002

Since the multicast group which is composed of various members is dynamic, members of the group frequently join or leave. So, for a new session, group keys are efficiently updated and distributed. In this paper, we describe very simple and new efficient logical key hierarchy(ELKH) protocol which is based on an one-way function. In the previous schemes, when the group controller distributes new created keys or updated keys to the members the information is usally encryted and then transmited over a multicast channel. But ELKH secretes the multicast message by using the one-way function and XOR operator instead of encrypting it. Hence our main construction improves the computational efficiency required from the group controller and group memebers while doesn't increase size of re-keying message when compared to $EHBT^{[12]}$. Assuming the security of an underlying one-way function, we prove that our scheme satisfies forward secrecy and backward secrecy.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.3
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• pp.67-78
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• 2010

CAS(Conditional Access System) is used in Pay-TV System to prohibit unauthorized user(s) accessing the contents in IPTV broadcasting environment. In the CAS, Smartcard transfers CW which is necessary in the process of descrambling the scrambled program to STB. CW hacking problem is one of the most serious problems in pay-TV system. There have been many researches on generating secure communication channel between smartcard and STB for secure transmitting, But they had problems in efficiency and security. In this paper, we propose a lightweight key agreement protocol based on a symmetric key algorithm. We show that our proposed protocol is more efficient than existing protocols by comparing the amount of computations, and analyzing the security requirement of the proposed protocol.

• Journal of Digital Convergence
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• v.18 no.12
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• pp.363-375
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• 2020

This study attempted to verify the structural model of the influence of parental intimacy, parental supervision, peer pressure, and TV alcohol advertising on drinking behavior for adolescents. It was conducted through a self-written questionnaire from May 1 to 28, 2019, targeting 602 students in grades 1 to 3 of 8 middle schools in G city. Results First, The direct effect on drinking behavior was in the order of peer pressure and TV alcohol advertisement, and they explained the degree of drinking behavior by 14.4%. second, Parental intimacy has an indirect effect on peer pressure and drinking behavior through TV alcohol advertising. Parental supervision has an indirect effect on drinking alcohol through TV alcohol advertisements. In multiple groups, there is a difference between the groups in the parental supervision and peer pressure, and the parental supervision and the channel coefficient of TV alcohol advertisement. In order to reduce drinking behavior, a realistic light that can cope with peer pressure is needed.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.2
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• pp.11-18
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• 2021

A community-centered smart village process model was developed through the theoretical review of the rural field forum. By analyzing the difference in technology demand according to the digital capabilities of leaders by community type, village types were classified and detailed technologies were defined. The smart village process was proposed to enable residents to operate autonomously by inducing continuous interest and participation of local residents through the conception stage, planning stage, implementation and self-reliance stage, and allowing them to cooperate together. The business model canvas was reconstructed to be used in the workshop. It was applied to the village of Yesan-gun. As a result of running a resident workshop using the business model Cambus, the lack of resident awareness and illegal garbage dumping were presented as the first problems to be solved. The value of the village was set as 'a village that is clean and clean with a sense of residents, and a good place to live', and users were expressed as 'family' and 'outsiders'. It was suggested that we meet frequently to convey the value of the village by using broadcasting and announcements as a channel to convey the value. Core activities were to cultivate residents' consciousness, such as implementing a campaign against illegal garbage dumping, and to establish and guide separate collection sites. When a garbage collection center is installed, it was estimated that around 2 million won per month for management costs, and it was investigated that it was possible to spend an hour or so twice a month to solve the problem of illegal dumping. If a method to derive village projects based on the derived business model canvas is developed in the future, it will be more practical.

• The Journal of Information Systems
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• v.31 no.1
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• pp.147-173
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• 2022

Purpose As the use of social network services has become common, it has become possible to freely communicate and establish relationships with other people anytime, anywhere for communication and information sharing. Influencers who have a strong influence on consumers' perceptions and attitudes through their own opinions and stories have appeared on various social media channels such as YouTube. Recently, companies utilize influencers with a large number of followers to check interactions with customers to understand customer attitudes and opinions about products in real time. Start-ups with insufficient resources need to quickly examine customer responses to reduce the probability of failure after product planning. The Lean process of creating an MVP and quickly confirming and learning the market response should be repeated over and over again. Findings In this paper, we try to suggest that the YouTube platform can play a sufficient role as a customer experiment space through examples. The case company is a company that has successfully commercialized products by continuously interacting with customers through the YouTube platform for the first four months of its founding. This paper is expected to be helpful in the experimental process for prospective founders and early founders to examine customer responses to reduce the probability of market failure before commercialization. Design/methodology/approach This paper analyzed the YouTube channel data of case companies based on the netnography methodology and presented the contents of the lean process management carried out in the experimental stage and the post-production stage through interview research.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.225-234
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• 2022

Voice commerce has emerged as a key channel for consumer searches and purchases. This study examines the continuance use intention of voice commerce, applying value-based adoption model. An online survey was conducted with 470 consumers who has experienced with voice commerce. As participants were who buys and purchases goods; or a user who uses food delivery service in voice commerce context. This study used SPSS 23.0 and Amos 23.0 for descriptive analysis, correlation analysis, confirmatory factor analysis, and structul equation modeling analysis. These reaults are as follows. First, usefuleness and response accuracy were significantly influenced the perceived value of voice commerce. Second, functional risk was significantly influenced the the perceived value of voice commerce. Third, perceived value was significantly influenced the continuance use intention of voice commerce. These results enhance understanding of voice commerce users and provide insight into the service provider of voice commerce.

• Ocean and Polar Research
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• v.44 no.1
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• pp.13-27
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• 2022

The Yeongsan River estuary was altered by a sea dike built in 1981 and the sluice gates in the dike were extended recently in 2014. The construction has caused changes in water properties and hydrodynamics and also produced disturbances including hypoxia and algal blooms. We analyzed the water quality and chlorophyll-a data (2009-2018) collected seasonally at 3 stations (Sts. 1-3) along the channel of the estuary by the Marine Environmental Monitoring System. Variations in water quality and chlorophyll-a (an index of phytoplankton biomass) were examined and their stressors were also identified by statistics including correlation and multivariate principal component analyses (PCA). The water quality was mainly affected by freshwater discharge from the dike. Salinity, nutrients and chlorophyll-a were especially affected by the discharge and the effect enhanced during summer and at the upper region near the sea dike decreasing downstream. Three factors were extracted for each station in the PCA accounting for 66.07-72.42% of the variations. The first was an external factor associated with freshwater discharge and the second and third were seasonal or biological factors. The results indicate that the water quality is more affected by short-termed and episodic events such as freshwater discharge than seasonal events and the influence of freshwater discharge on water quality is more extensive than that previously reported. This suggests that the boundary of the estuary should be extended to take into account the findings of this study and a management strategy linked to the freshwater zone is required to manage the integrity and water quality of the Yeongsan River estuary.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1674-1685
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• 2022

The ball valve is an important device in the pipeline transportation system of nuclear power plants. Its operational stability and safety directly affect the normal working of nuclear power plants. In this study, the transient numerical simulation of the opening and closing process of a ball valve was conducted on the basis of the flow interruption capability experiment of the ball valve by using the moving mesh method and inlet and outlet variable boundary conditions. The flow rate and pressure difference with time of the opening and closing process of the ball valve were studied. The internal flow characteristics of the ball valve under different relative openings were analyzed in conjunction with the typical back-step flow structure. Results show that the transient numerical results agree well with the experimental results. The internal flow characteristics of the ball valve are similar at the same opening during opening and closing process. At small opening, the spool and outlet channels easily form a back-step flow structure. The disappearance and generation of backflow vortices during opening and closing occur at 85% opening and 75% opening, respectively. With the decrease in opening degree, the difference in vortex core area in the flow channel of the ball valve spool in the opening and closing process gradually appears. The research results provide some reference value for the design and optimization of ball valves.