• Journal of Digital Contents Society
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• v.7 no.2
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• pp.103-108
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• 2006

Short-range wireless communication and networking technologies are becoming increasingly important in enabling useful mobile applications. for example, ZigBee technology is expected to provide low cost and low power connectivity for equipment that needs battery life as long as several months to several years. In addition, ZigBee can be implemented in mesh networks larger than is possible with Bluetooth. The main features of this ZigBee standard are network flexibility, low cost, very low power consumption, and low data rate in an adhoc self-organizing network among fixed, portable and moving devices. Home network/Home automation is one of the key market areas for Zigbee, with an example of a simple network This paper investigates the effect of short range wireless channel on the performance of Zigbee system and DSSS-BPSK signal transmission in AWGN, interference and Rician fading environments. And we investigate performance degradation due to interference and fading effects in short range wireless channel. In particular, the impacts of the fading and interference level on the bit error probability is shown in BER performance figures.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3B
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• pp.112-122
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• 2008

Basing on Piconet, The Bluetooth System forms network and transmits data. There is one Master and maximum 7 Slave bluetooth devices in one piconet. A job scheduler performed by Master bluetooth device, gives the chance of data transmission to Slave bluetooth devices, which connected to Master, using polling method in piconet. The maximum data rate is 723.2 kb/s when it uses ACL link with DH5 packet type in a piconet which is constructed by two bluetooth devices. However, if there are one master and two slave devices in a piconet, then the maximum data rate is reduced to a half(361.6kb/s), because a master device has to support same data rate for all connected devices. And, there is the defect in scatternet when data transmission rate becomes low(Maximum rate: 302.2kb/s). This paper proposals the new ad-hoc network topology called "DoublePico"for overcome the low data transmission in scatternet which is constructed by piconets. The method of doublepico that represented in this paper makes high data transfer rate(Maximum rate: 457.57kb/s) in bluetooth ad-hoc networks.

• The KIPS Transactions:PartC
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• v.17C no.2
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• pp.215-222
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• 2010

IEEE 802.15 WPAN(Wireless personal area network) technologies represented by Bluetooth are prevalent these days. However, they have short radio coverage and thus cannot be used to build a SNS for servicing users spread over a wide area. In this paper, we develop a mobile SNS(Social Network System) that does not necessitate any infrastructure support using the Bluetooth technology and the mobility based information dissemination technique. Using so-called mobility assisted data dissemination technique we overcome the short radio range restriction of WPAN technologies. We develop Blue Market, a free online marketplace program, as a proof of concept.

• Journal of Digital Contents Society
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• v.8 no.3
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• pp.323-328
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• 2007

Communication systems beyond 3G should provide more than 100 Mbps for wireless access. In addition to smart antennas, wireless multi-hop networks are proposed to increase the cell size and throughput. For example, Zigbee technology is expected to provide low cost and low power connectivity and can be implemented in wireless mesh networks larger than is possible with Bluetooth. Also, home embedded system using wireless mesh network is one of the key market areas for Zigbee applications. If the line-of-sight path is shadowed by home obstacles, a direct connection between the access point (AP) and the node is not possible at high frequencies. Therefore, by using multi-hop relay scheme the end node can be reached to AP. In this paper, the relaying of data between the AP and the end node is investigated and the throughput and PER(Packet Error Rate) are evaluated in multi-hop wireless mesh networks by using DSSS/BPSK system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.242-246
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• 2005

RFID(Radio Frequency Identification) which is emerging from a change in digital convergence paradigm and recently rapidly advancing throughout the overall society is the core technology based on Ubiquitous network. In other words, This is a technology to identify the information of the object and recognize the situation by attaching electrical tag to an object and using Reader that can read the information of the object. With the emergence of the technology, it has turned the existing maintenance of the product into the network and intelligence of the product control by using the bar cord to maintain the product and will lead a revolution throughout overall society by affecting the fields of distribution and product maintenance as well as those of medicines, chemicals and food which the electrical tag can be attached to. his paper shows that utilizing the Bluetooth which is a local wireless telecommunication in the standalone imbedded system can implement the piconet configuration among the Readers and the data telecommunication with the main server.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.613-619
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• 2020

Hybrid media access control (MAC) is used in internet of things (IoT) network, because of communication feature concern with data capacity and communication interval between gateway and sensor nodes and the cost efficiency. Hybrid MAC consists of TDMA and CSMA generally. The distance between gateway and sensor node is openly changed in marine IoT network. Therefore, it is needed to control the period of timeslot of hybrid MAC used in marine IoT network. In this paper, the design rule of TDMA timeslot with the variable period depending on communication distance was proposed. It was confirmed from the analysis that 72 times communication between gateway and sensor nodes is possible in LoRa network by using the proposed TDMA variable timeslot scheme.

• Journal of KIISE:Information Networking
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• v.33 no.2
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• pp.139-148
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• 2006

Recently with the advancement of local wireless communication technologies, digital trends of audio contents and devices are paving the way for new experiences to network-based audio streaming services. In this paper, we present the Wireless Audio Sharing (WASH) technology over Bluetooth and Wireless Local Area Network (WLAN). WASH system provides an audio sharing mechanism over multiple users and also provides stereo audio streaming between Bluetooth-enabled devices and Universal Plug and Play (UPnP) media devices connected to wired/wireless LANs. To achieve these, we extended the Bluetooth audio distribution profile and combined the extended profile with the UPnP AV architecture. With the implementation of this WASH technology, we show some experimental results of the stereo audio streaming in a real environment.

• Journal of Digital Contents Society
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• v.19 no.5
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• pp.963-969
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• 2018

Wi-Fi and Bluetooth technologies are perhaps the most prominent examples of wireless communication technologies used in the Internet of Things (IoT) environment. Compared to widely used Wi-Fi, Bluetooth technology has some flaws including 1:1 connection (one-way) between Master and Slave, slow transmission, and limited connection range; Bluetooth is mainly used for connecting audio devices. Since the release of Bluetooth Low Energy (BLE), some of the flaws of Bluetooth technology have been improved but it still failed to become a competitive alternative of Wi-Fi. This paper presents a method of data transmission through broadcasting in BLE and demonstrates its performance, one-to-many data transfer result. The Connection-Free Data Transmission proposed in this paper will hopefully be utilized in special circumstances requiring 1:N data transmission or disaster security network.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.137-143
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• 2009

Through the development of techniques, robots are becomes smaller, and many of robots needed for application are greater and greater. Method of coordinating large number of autonomous robots through local interactions has becoming an important research issue in robot community. Swarm Robot System is a system that independent autonomous robots in the restricted environment infer their status from preassigned conditions and operate their jobs through the coorperation with each other. Within the SRS,a robot contains sensor part to percept the situation around them, communication part to exchange information, and actuator part to do a work. Specially, in order to cooperate with other robots, communicating with other robot is one of the essential elements. In such as Bluetooth has many adventages such as low power consumption, small size module package, and various standard procotols, it is rated as one of the efficent communcating system for autonomous robot is developed in this paper. and How to construct and what kind of procedure to develop the communicatry system for group behavior of the SRS under intelligent space is discussed in this paper.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5946-5956
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• 2011

The purpose of this study is to discourage urban sprawl that optimize the use of natural resources and reduce demand for transportation, energy consumption, and also protect green and blue networks. For this purpose, this study discusses about the Sustainable Development (SD), urban systems toward SD and defines the concepts and the goals of Green Compact City (GCC). It then finds out the basic planning strategies to agree with GCC. Based on these strategies, it reviews the foreign case study, to obtain a mainly significance development of these planning strategies. As well as then conducts a questionnaire survey to experts and residents of Ulaanbaatar (UB) city to obtain a better understanding of the current condition and the most significant planning strategies in UB city. Therefore the basic planning strategies which can more suits in UB city and it could be the GCC is derived from the most complied planning strategies in other developed countries compared with most significant planning strategies in UB city.