• Journal of KIISE:Databases
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• v.36 no.3
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• pp.169-179
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• 2009

Communication log data consist of communication events such as sending and receiving e-mail or instance message and visiting web sites, etc. Many countries including USA and EU enforce the retention of these data on the communication service providers for the purpose of investigating or detecting criminals through the Internet. Because size of the retained data is very large, the efficient method for extracting valuable information from the data is needed for Law Enforcement Authorities to use the retained data. This paper defines the Interactive Communication Sequence Patterns(ICSPs) that is the important information when each communication event in communication log data consists of sender, receiver, and timestamp of this event. We also define a Mining(FDICSP) problem to discover such patterns and propose a method called Fast Discovering Interactive Communication Sequence Pattern(FDICSP) to solve this problem. FDICSP focuses on the characteristics of ICS to reduce the search space when it finds longer sequences by using shorter sequences. Thus, FDICSP can find Interactive Communication Sequence Patterns efficiently.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.2 no.1 s.2
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• pp.15-24
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• 2003

While public institutions and privite coperations have constructed the data collecting infrastructure and commercialized it to service traffic information, inaccuracy with information, insufficiency with the public sector, overapping investment and the rest are arising from the differences of data treatment, offering method, communication protocal and the like. For these reasons, we need standardization it as a national enterprise. In this paper, we would like to present the unity management and joint method of traffic information based on the present position of system construction and national ITS standardization. At first, we presented the relation between data elements and message sets and then analyzed how message sets have been used to message sets to share traffic information so far in public institutions and private coperations like Korea freeway cooperation-ITS model city-Cheonan-Nonsan expressway, In-cheon international airport expressway-Korea freeway cooperation and Seoul metropolitan police agency-Seoul metropolitan government. As the results of analyzing message sets, it had disclosed that data transmission is impossible or a system is unchangeable because data form and each items to transmission were different from each other and its own address and link IDS were not determined yet. Also it showed these message sets did not abidy by The Draft of National ITS Standards. First of all, we proposed data basic form and elements which were form by items used in each center in common and the elements to manage traffic information suggested by Standards based on the results of analyses.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.6
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• pp.145-154
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• 2018

A loosely coupled message broker system is a popular method for integrating distributed software components. Especially, a distributed broker structure with multiple brokers with active-standby or active-active message replicas are used to enhance availability as well as message processing performance. However, there are problems in both active-standby and active-active replica structure. The active-standby has relatively low processing performance and The active-active structure requires a high synchronization overhead. In this paper, we propose an active-active structure of replicas to increase the availability of the brokers without compromising its high fault-tolerancy. In the proposed structure, standby replicas process the requests of the active replicas so that load balancing is achieved without additional brokers, while the distributed coordinators are used for the synchronization process to decrease the overhead. We formulated the overhead incurred when synchronizing messages among replicas, and the formulation was used to support the experiment results. From the experiment, we observed that replicas of the active-active structure show better performance than the active stand-by structure with increasing number of users.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.11
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• pp.2992-3007
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• 2012

Recently there has been an increasing interest in exploring the radio irregularity research problem in Wireless Sensor Networks (WSNs). Measurements on real test-beds provide insights and fundamental information for a radio irregularity model. In our previous work "LMAT", we solved the path planning problem of the mobile anchor node without taking into account the radio irregularity model. This paper further studies how the localization performance is affected by radio irregularity. There is high probability that unknown nodes cannot receive sufficient location messages under the radio irregularity model. Therefore, we dynamically adjust the anchor node's radio range to guarantee that all the unknown nodes can receive sufficient localization information. In order to improve localization accuracy, we propose a new 2-hop localization scheme. Furthermore, we point out the relationship between degree of irregularity (DOI) and communication distance, and the impact of radio irregularity on message receiving probability. Finally, simulations show that, compared with 1-hop localization scheme, the 2-hop localization scheme with the radio irregularity model reduces the average localization error by about 20.51%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.525-531
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• 2010

In this paper, a mobile quiz system using SMS has been developed, which can be conveniently used on the spot of education. The system immediately not only provides each individual student with the results of his/her quizzes but also a instructor with the statistics of the results by SMS. Field tests of the quiz system have shown that it can be effectively used as a good teaching tool for teachers getting immediate feedback from participants in the lecture and adjusting teaching level as well as for inducing more interest in learning from participants and raising their concentration on the class.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.7
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• pp.3678-3698
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• 2017

With the rapid development of vehicular ad hoc Network (VANET), it has gained significant popularity and received increasing attentions from both academics and industry communities in aspects of security and efficiency. To address the security and efficiency issues, a self-authentication and deniable efficient group key agreement protocol is proposed in this paper. The scheme establishes a group between road side units (RSUs) and vehicles by using self-authentication without certification authority, and improves certification efficiency by using group key (GK) transmission method. At the same time, to avoid the attacker attacking the legal vehicle by RSUs, we adopt deniable group key agreement method to negotiation session key (sk) and use it to transmit GK between RSUs. In addition, vehicles not only broadcast messages to other vehicles, but also communicate with other members in the same group. Therefore, group communication is necessary in VANET. Finally, the performance analysis shows superiority of our scheme in security problems, meanwhile the verification delay, transmission overheard and message delay get significant improvement than other related schemes.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.19-26
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• 2014

The advent of smart phones brought adverse effect between devices recently. For example, adverse effects of info-communication with advent of computer. Also, hacking threat aiming cyber space that is getting more advanced is spreading in terms of range and danger, so that it reaches the level that the nation has to concern. In this circumstance, crimes involving info-technology is now problem in society. As internet technology advances, it enlarges the range of hacker's threat to not only smart phones, but ships, aircrafts, buildings, and cars. It could be seen as social threat of between human and human, between machine and machine, and between human and machine. This study discuss these problems.

• Korean journal of communication and information
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• v.48
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• pp.191-210
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• 2009

In this study, we examined the influence of news frame and involvement on risk perception. Based on individuals' optimistic bias in risk judgement and the third-person effect theory, we developed research hypotheses. An experiment was conducted in which 243 undergraduate and graduate students participated. Results indicated that societal level risk judgements were relatively invariant across experimental conditions but personal level risk judgements were influenced by the news frame and individuals' involvement in irradiated food. Based on the results, we provide explanations concerning when and how optimistic bias takes place in each experimental condition.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.740-754
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• 2015

This paper focuses on the reverse blocking busbar protection scheme with aim to improve the speed of its operation and at the same time to increase operational reliability, flexibility and stability of the protection during external and internal faults by implementation of the extended functionality provided by the IEC61850 standard-based protective Intelligent Electronic Devices (IEDs). The practical implementation of the scheme by the use of IEC 61850 standard communication protocol is investigated. The proposed scheme is designed for a radial type of a distribution network and is modeled and simulated in the DigSILENT software environment for various faults on the busbar and its outgoing feeders. A laboratory test bench is built using three ABB IEDs 670 series that are compliant with the IEC 61850 standard, CMC 356 Omicron test injection device, PC, MOXA switch, and a DC power supplier. Two types of the reverse blocking signals between the IEDs in the test bench are considered: hard wired and Ethernet communication by using IEC 61850 standard GOOSE messages. Comparative experimental study of the operational trip response speeds of the two implementations for various traffic conditions of the communication network shows that the performance of the protection scheme for the case of Ethernet IEC 61850 standard-based communication is better.

• Asian Journal for Public Opinion Research
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• v.1 no.2
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• pp.73-89
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• 2014

Everyone has a voice and can broadcast it to the world. We hear about the old maxim of media do not tell people what to think but what to think about. Under this theory or approach, a key function of political communication is to make the public think about an issue in a way that is favorable to the sender of the message. In a democracy, political communication is seen as crucial for the building of a society where the state and its people feel they are connected. Thus, this is a study on how social media (e.g., Facebook, blogs, and YouTube) were used in the domain of Malaysian politics during the 13th general election campaigning period in order to set the agenda to form public opinion. The study found that Facebook was the most popular social media tool that political parties actively engaged with during the 13th general election campaign period. Apart from that, issues pertaining to the election were significantly highlighted by the political parties in social media, especially Facebook. However, other issues that were also important to the people such as the economy, crime, and education were not sufficiently highlighted during the election campaign period. This indicates that the political parties influence the public on what to think about using social media.