• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4411-4431
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• 2014

Mobile ad hoc networks (MANETs) have recently gained increased interest due to the widespread use of smart mobile devices. Group communication applications, serving for better cooperation between subsets of business members, become more significant in the context of MANETs. Multicast routing mechanisms are very useful communication techniques for such group-oriented applications. This paper deals with multicast routing problems in terms of stability and scalability, using the concept of stable core. We propose LMRSC (Lightweight Multicast Routing Based on Stable Core), a lightweight multicast routing technique for MANETs, in order to avoid periodic flooding of the source messages throughout the network, and to increase the duration of multicast routes. LMRSC establishes and maintains mesh architecture for each multicast group member by dividing the network into several zones, where each zone elects the most stable node as its core. Node residual energy and node velocity are used to calculate the node stability factor. The proposed algorithm is simulated by using NS-2 simulation, and is compared with other multicast routing mechanisms: ODMRP and PUMA. Packet delivery ratio, multicast route lifetime, and control packet overhead are used as performance metrics. These metrics are measured by gradual increase of the node mobility, the number of sources, the group size and the number of groups. The simulation performance results indicate that the proposed algorithm outperforms other mechanisms in terms of routes stability and network density.

• The Journal of the Korea Contents Association
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• v.16 no.5
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• pp.1-12
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• 2016

Internet of Things (IoTs) technologies have been computerized information generated from a variety of objects and humans, and have been applied to various fields by connecting via the Internet. In order to compensate for the marginal characteristics of IoT smart devices, such as low-power, limited processing and capacities, combining IoT and cloud computing technologies is now established itself as one of the paradigms. In this paper, we look at the definition, features and services of IoT and cloud computing technology, and we investigate and analyze the conversing needs of IoT and could computing, existing conversion paradigms, convergence cases, and platforms. In results, there are challenges to be solved, even though the cloud technologies complement a number of restrictions of IoT and offer various advantages such as scalability, interoperability, reliability, efficiency, availability, security, ease of access, ease of use, and reduced cost of deployment. We analyze the new research issues of convergence paradigm, and finally suggest a research challenges for convergence.

• Journal of Digital Contents Society
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• v.18 no.1
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• pp.55-62
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• 2017

The background of this study is the trend in which the genres of mobile games are becoming diverse based on advanced smart devices. However, since cut-scenes are still being regarded as somewhat unnecessary elements in digital games, this study seeks to suggest the functions and range of uses of cut-scenes. The scope of this study is to make classifications for the range of uses of cut-scenes in commercialized mobile games according to the genre, and investigate the characteristics of visual expression to create a frame for communicative styles of mobile games. The result of study was that different styles were identified regarding the use of cut-scenes in mobile games just as in existing digital games, however diverse attempts are not yet being made as in early digital games. Future study needs to be carried out on communication styles that match the characteristics of mobile game platforms, in which a module that can be applied in the introduction of a new platform is required.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.242-249
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• 2009

High-rise construction sites, especially those situated in spatially constrained urban areas, have difficulties in timely delivery of materials. Modern techniques such as Just-in-time delivery, and use of information technology such as Project Management Information System (PMIS), are targeted to improve the efficiency of the logistics. Such IT-driven management techniques can be further benefited from state-of-the-art devices such as Radio Frequency Identification (RFID) tags and Ubiquitous Sensor Networks (USN), which has resulted in notable achievements in automated logistics management at the construction sites. Based on those achievements, this research develops USN hardware toolkits for construction lifts, which aims to be automated the vertical material delivery by sensing the material information and routing it automatically to the right place. The gathered information from the sensors can also be used for monitoring the overall status. The developed system will be tested in the actual high-rise construction sites to assess the system's feasibility. The proposed system is being implemented using Zigbee communication modules and RFID sensor networks which will communicate with the intelligent palette system (previously developed by the authors). To support the system, a lift-mountable intelligent toolkit is under development. Its feasibility test will be conducted by applying the implemented system to a test bed and then analyzing efficiency of the system and the toolkit. The collected test data will be provided as a basis of autonomous vertical transport equipment development. From this research, efficient management of the material lift is expected with increased accuracy, as well as better management of overall construction schedule benefited from the system. Further research will be expected to develop a smart construction lift, which will eliminate the need for human supervision, thus enabling a real 'autonomous' operation of the system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.5
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• pp.207-214
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• 2020

Nowadays, the use of smart phones and various electronic devices is increasing, the Internet and SNS are activated, and we live in the flood of information. The amount of information has grown exponentially, making it difficult to look at a lot of information, and more and more people want to see only key keywords in a document, and the importance of research to extract topics that are the core of information is increasing. In addition, it is also an important issue to extract the topic and compare it with the past to infer the current trend. Topic modeling techniques can be used to extract topics from a large volume of documents, and these extracted topics can be used in various fields such as trend prediction and data analysis. In this paper, we inquire the topic of the three-year papers of 2016, 2017, and 2018 in the field of computing using the LDA algorithm, one of Probabilistic Topic Model Techniques, in order to analyze the rapidly changing trends and keep pace with the times. Then we analyze trends and flows of research.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.5
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• pp.2103-2123
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• 2018

Ships built today are larger in scale and feature more complex structures. The ever-evolving systems used on board a ship require vast amounts of data processing. In the future, with the advent of smart ships, unmanned ships and other next-generation ships, the volumes of data to be processed will continue to increase. Yet, to date, ship data has been processed using wired networks. Placed at fixed locations, the nodes on wired networks often fail to process data from mobile devices. Despite many attempts made to use Wi-Fi on ships just as on land to create wireless networks, Wi-Fi has hardly been available due to the complex metal structures of ships. Therefore, Wi-Fi on ships has been patchy as the ship-wide total Wi-Fi coverage has not properly implemented. A new ship-wide wireless network environment is part of the technology conducive to the shipbuilding industry. The wireless network environment should not only serve the purpose of communication but also be able to manage and control multiple features in real-time: fault diagnostics, tracking, accident prevention and safety management. To better understand the characteristics of wireless frequencies for ships, this paper tests the widely used TETRA, UHF and Wi-Fi and sheds light on the features, advantages and disadvantages of each technology in ship settings. The proposed deployment of a Super Wi-Fi network leveraging the legacy UHF system of TMS generates a ship-wide wireless network environment. The experimental findings corroborate the feasibility of the proposed ship-wide Super Wi-Fi network environment.

• Knowledge Management Research
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• v.23 no.1
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• pp.1-26
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• 2022

With the spread of social networks, platform-based social commerce has grown rapidly with the use of multiple smart devices. Given the rapid growth of social commerce sites such as Coupang and Ticket Monster, it is very important to understand the user's purchase decision-making process in a social commerce environment. The purpose of this study is to develop a richer understanding of the goals of users using social commerce. Second, a methodological alternative for analyzing the user's goals is introduced. In this study, laddering interview and means-end chain analysis were used. As a result of interview conducted on 40 users who have more than 6 months of purchasing experience using social commerce, a hierarchical goal map showing the user's goal structure was derived. This map contains 22 ultimate goals of social commerce, including warm relationships with others, fun and enjoyment of shopping, accomplishment, satisfaction, financial saving, and convenience. In addition, there are various paths from activities to ultimate goals, so investigating the goals pursued by users can give us insight into understanding user.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.584-587
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• 2012

MANET, which can be constructed with only terminal devices, has structural advantages of ease installation and operation, also has environmental change of rapid supply of smart phone, it's usage can be extended to application area likes as emergency communication, leasure, exploration and investigations. But, as one characteristic of MANET, no use of communicaton infrastructure caused disadvantage of weakness for information intrusion which is frequently occurred, nowadays. In this paper, the effects of IDS(Intrusion Detection System), one of defence tools for information intrusion, is analyzed for transmission performance. Blackhole attack is assumed as a type of intrusion, MANET defence with IDS from intrusions. Computer simulation based on NS-2 used for performance measurement. In this paper, performance measurement is done for application service to analyze application level effects of IDS. VoIP service is used as application service.

• Korean journal of communication and information
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• v.60
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• pp.172-192
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• 2012

Over the last ten years, media convergence and multiple platform expansion have affected the ways that people watch conventional television. In the post-TV era, the growing use of the Internet and mobile multi-media devices, such as smart phones, as well as the availability of abundant television content, allows television consumption to be more personalized, diversified, and linked with various media activities, especially social media uses. This study attempts to examine how television viewing experiences have been transformed with the development of the trans-media uses. Based on Walter J. Ong's concept of relation-ism, which posits that new media transform the meanings and relevance of old media rather than making old media obsolete, this study will pay particular attention to how the cultural meanings of television viewing have been redefined in the post-TV era. For the examination, this study has looked at concrete cases of the television viewing experiences of 29 young people in their twenties. Based on in-depth interview data, this study discusses the newly emerging characteristics of television viewing, its temporal and spatial experiences, and the significance of television as a medium and as a social place.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1865-1872
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• 2013

The social network services are grown rapidly through dissemination of smart devices. Therefore, increasing the data exponentially because many people use web services. Using these big data, it will be needed study of providing customized knowledge. So in this paper, we had collected data of 40 people for implementation of knowledge service using big data during one month. Based on these data, we had inferred information of location and moving type, and evaluated accuracy. Through that we had studied personal experience knowledge evaluation model for knowledge service.