• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.1
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• pp.69-78
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• 2015

Internet of Things(IoT) is electronic devices and household appliances use wireless sensor network in environment of high speed wireless network and LTE mobile service. The combination of the development of Internet and wireless network led to development of new forms of service such as electronic devices and household appliances can connect to the Internet through various sensors and online servers such as a Home Network. Even though Internet of Things is useful, there are problems in Internet of Things. In environment of Internet of Things, information leakage could happens by illegal eavesdropping and spoofing. Also illegal devices of wireless communication interference can cause interfere in Internet of things service, physical damage and denial of service by modulation of data and sensor. In this thesis, it will analyze security threats and security vulnerability in environment of mobile services and smart household appliances, then it will suggest plan. To solve security issues, it is important that IT and RFID sensor related companies realize importance of security environment rather than focus on making profit. It is important to develop the standardized security model that applies to the Internet of Things by security-related packages, standard certification system and strong encrypted authentication.

• Journal of Advanced Navigation Technology
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• v.8 no.2
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• pp.169-175
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• 2004

We analyzed about digital watermarking embedded transmission of still image in wireless multimedia communication environment. Also, we proposed improved watermark techniques. It effects that get in original image than method to use conventional image is less and shows robust watermark restoration ability from outside attack. Performance analysis achieved about still image and restoration of watermark information using OFDM/QPSK still image transmission system in wireless channel environment. Analysis result, VI watermark performance that influence in original image is very small. And it could know that show high restoration performance. Also, It showed superior copyright information extraction performance than image watermark in wireless channel environment of same transmission error condition.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.286-289
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• 2002

This paper proposes wireless fan system as noise measurement system. It is easy to combine measurement system(Hardware) and analytic system(software) to the Wireless tan system. Thus wireless fan system can be applied to noise mapping system and noise monitoring system. This paper show noise measurement experiment and result using wireless lan system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2279-2284
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• 2017

Recent wireless communications using the unlicensed band have been on the rise and the range of use is increasing. The license-exempted band is a prerequisite for accepting interference between telecommunication equipment. In particular, the interference phenomenon of Bluetooth, wireless LAN, and RFID (Radio Frequency Identification) using the 2.4 GHz band is getting serious. In such urban areas, the wireless transmission medium may be in a bad state. There are roughly two ways to make effective transmission in this environment. The first is the IEEE 802.11 RTS / CTS method and the second is the frame fragmentation method. In this paper, it is difficult to transmit a frame over a certain size in a jamming environment due to the interference of the wireless environment. In this environment, we implement a frame division transmission scheme that guarantees effective transmission and reliability by dividing a frame into smaller units in order to perform reliability transmission and efficient transmission.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.203-209
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• 2012

Recently, k-nearest neighbors query methods based on wireless broadcasting environment are actively studied. The advantage of wireless broadcasting environment is the scalability that enables collective query processing for unspecified users connected to the server. However, in case existing k-NN query is applied in wireless broadcasting environment, there can be a disadvantage that backtracking may occur and consequently the query processing time is increasing. In this paper proposes a hierarchical bitmap-based spatial index in order to efficiently process the k-NN queries in wireless broadcasting environment. HBI reduces the bitmap size using such bitmap information and tree structure. As a result, reducing the broadcast cycle can reduce the client's tuning time and query processing time. In addition, since the locations of all the objects can be detected using bitmap information, it is possible to tune to necessary data selectively. For this paper, a test was conducted implementing HBI to k-NN query and the proposed technique was proved to be excellent by a performance evaluation.

• 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.

• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.333-338
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• 2019

Cultural contents are the most important factor in high speed and high quality data communication. High-quality content includes VR and AR technology, and a variety of high-quality content can be streamed over wireless mobile phones via smartphones. In addition, network and wired/wireless communication are inevitably required in an Internet of Things (IoT) environment in which things are connected to a wireless Internet. IoT is used in various network technologies such as 4G, 5G mobile communication, WIFI wireless LAN, Bluetooth and so on. It is a technology that can use the connection between things anytime, anywhere, and can be achieved in a wireless mobile communication environment. Therefore, in this paper, we study data error compensation estimation method which can reduce data error based on mobile communication channel environment analysis so that high quality contents can be serviced even in high speed mobile environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.753-757
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• 2005

Wireless LAN was developed by alternative of LAN and because establishment was easy, have used into special field and special expenditure. Recently, Standard and a technology developed by leaps and bounds. Present is used into purpose of the Building to Building or wide connection etc. and relay of the high speed Internet and usage of picture communication that require multimedia band width. Specially, campus wireless LAM is thought that must secure radius $100\;\~\;200\;m$ dimension at the minimum 10Mbps speed as Internet transit trunk. But, there is difference as degressive here. In this paper, wireless LAN measured for effectiveness proof as Internet transit trunk in actuality utilization environment. Proved that should compose IEEE802.11b as AP more than minimum 3 when compose network to base as measuring result. Hereafter, there is the purpose that achieve performance evaluation of wireless UM in marine environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.357-360
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• 2008

Vital sign monitoring system using IEEE 502.IS.4 based wireless sensor network(WSN) is designed and developed on mobile environment and sensor node platform. WSN and CDMA are integrated to create a wide coverage to support various environments like inside and outside. We developed query processor to use selective any devices(ECG, Blood pressure and sugar module) and control of the self-organizing network of sensor nodes in a wireless sensor network. Vital sign from wireless medical any devices are analysed in cell phone first for real time signal analyses and the abnormal vital signs are sent and save to hospital server for detail signal processing. wireless signal traffic in wireless sensor network environment or data communication inside the cell phone is reduced.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.1038-1041
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• 2009

Wireless sensor network with wireless sensor nodes which equipped with temperature, humidity, illumination, or soil sensor etc, get a natural environment information and analyze and utilized variety way.these network consist of a short distance wireless communication and multi-hop techniques with multiple nodes equipped low-power wireless transceivers. so the characteristic of the data collected through the wireless sensor network is obtained from compact nodes within a limited range. However, to get a data from the wireless sensor nodes scattered in a wide range, this network needs a wireless transceiver that consumes many power or a lot of intermediate nodes. then, merit of low cost and low electrical energy decrease. To solve this problem, this paper offers environment monitoring system using autonomous mobile robot that collect data from groups of each sensor networks scattered widely.