• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.4
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• pp.109-116
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• 2014

In recent, ISM (Industrial Scientific Medical) band that is 2.4GHz band authorized free of charge is being widely used for smart phone, notebook computer, printer and portable multimedia devices. Accordingly, studies have been continuously conducted on the possibility of coexistence among nodes using ISM band. In particular, the interference of IEEE 802.11b based Wi-Fi device using overlapping channel during communication among IEEE 802.15.4 based wireless sensor nodes suitable for low-power, low-speed communication using ISM band causes serious network performance deterioration of wireless sensor networks. This paper examined a method of identifying channel status to avoid interference among wireless communication devices using IEEE 802.11b (Wi-Fi) and other ISM bands during communication among IEEE 802.15.4 based wireless sensor network nodes in ISM band. To identify channels occupied by Wi-Fi traffic, various studies are being conducted that use the RSSI (Received Signal Strength Indicator) value of interference signal obtained through ED (Energy Detection) feature that is one of IEEE 802.15.4 transmitter characteristics. This paper examines an algorithm that identifies the possibility of using more accurate channel by mixing utilization of interference signal and RSSI mean value of interference signal by wireless sensor network nodes. In addition, it verifies such algorithm by using OPNET Network verification simulator.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.1923-1930
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• 2012

'No-Automobile driving Day' is one of Special option of Automobile Insurance in Republic of Korea. It option is used a system for collect to automobile driving information. However, Its system gives discomfort to users of this system. A Discomfort of this system to users is the OBD device's(Personal Car Driving Check Device) installation. A frequent installation of this device provides this OBD device's breakage to the users of this system. In this paper, for a solve this problem, studied new system design to supplement the existing system using Smartphone and WPAN(Wireless Personal Area Network).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2114-2120
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• 2015

Vehicle cloud technology is a fusion technology of vehicle communication technology and cloud computing used in wired and wireless Internet, and has attracted attention as a new IT paradigm. It is expected that it would contribute to resolve the road traffic problem with effective communication by providing computer, sensor, communication, device, and resource. but security is necessary to apply vehicle cloud environment and it have to resolve security threats and various attacks occurred in wired and wireless vehicle environment. Therefore, in this paper, we designed security framework to provide secure communication between vehicle and vehicle, and vehicle and the Road side in the vehicle cloud environment. Safety and security of the vehicle environment was satisfied with the security requirements of the vehicle and cloud-based environment, and increased efficiency than the conventional vehicle network communication protocols.

• Journal of Advanced Navigation Technology
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• v.11 no.4
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• pp.408-414
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• 2007

Research advances in the areas of micro-sensor device and wireless network technology, has made it possible to develop energy efficient and low cost wireless sensor nodes. In this paper, the forward error control (FEC) scheme for lower power consumption and excellent BER(Bit Error Rate) performance during transmission propose in multi-hop wireless sensor network based on FSK modem. The FEC technique uses extra processing power related to encoding and decoding, it is need complex functions to be built into the sensor node. The probability of receiving a correct bit and codeword for relaying a frame over h nodes to the sink node is calculated as a function of channel parameter, number of hops, number of bits transmitted and the distance between the different nodes.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.2
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• pp.57-65
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• 2008

Wireless sensor networks achieve environment monitoring and controlling through use of small devices of low cost and low power. Such network is comprised of several sensor nodes, each having a microprocessor, sensor, actuator and wired/wireless transceiver inside a small device. In this paper, we employ the sensor networks in order to design and implement a real-time vehicle safety system. Such system can inform the safe velocity in a specific weather condition to drivers in advance through analyzing the weather data collected from sensor networks. As a result, the drivers can prevent effectively accidents by controlling their car speed.

• The KIPS Transactions:PartD
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• v.11D no.5
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• pp.1073-1086
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• 2004

Wireless internet is embossed the new keyword of IT technology in the world lately. The wireless internet is the architecture, technology and service to be can taken data communication and internet service using wireless device through connecting internet in the wireless environment. These wireless internet technology is extends the scope of using information with the existing wire internet technology. But, It is necessary to be extend supply of quantitative and qualitative for using wireless internet technology efficiently. For these matters, it is efficient to reuse good qualify contents that is serviced on wire environments. Then, in this paper, design and implement the technique of creating con-tents that is made by the method of compounding parts based on the contents automatic reuse technology over the concept of creating new wireless contents.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.11
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• pp.123-129
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• 2011

In terrestrial wireless optical communication links, atmospheric effects including turbulence, absorption and scattering have significant impact on the system performance. Based on the analysis of transmission in atmospheric channel concerning 830[nm] wavelength diode laser beam, performance of free space optical (FSO) link utilizing Galilean optics as a laser beam transmitting and receving optics, PIN photodiode as a detecting device. In this paper we designed optical link equation for received optical power and we analyze the atmospheric effects on the signal to noise ratio (SNR) and bit error rate (BER) of an terrestrial FSO system. We show that the possible communication distance for BER=$10^{-9}$ in proposed adverse atmospheric conditions.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.63-68
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• 2003

For effective conservation of ocean and harbor, long-term and systematic development of the ocean and harbor monitoring system is essential. The monitoring system capable of real-time and accurate data acquisition is necessary for dealing with contamination such as red tide and the flood. This paper introduces the effective and economical real-time harbor environmental monitoring system that utilizes PCS wireless data communication technology. The monitoring system has various functions such as multiple communication, TCP/IP protocol for wireless internet access, system time synchronization, bi-directional communication between the measuring device and the server. The system has been implemented at Shinseondae harbor pier in Busan to validate the systems stability and effectiveness in data acquisition. The acquired real-time ocean and harbor environmental data is expected to have a large effect, when shared by public through internet.

• ETRI Journal
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• v.34 no.3
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• pp.319-329
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• 2012

Closed-loop transmit diversity is considered an important technique for improving the link budget in the third generation and future wireless communication standards. This paper proposes several transmit diversity algorithms suitable for small wireless terminals and presents performance assessment in terms of average signal-to-noise ratio (SNR) and outage improvement, convergence, and complexity of operations. The algorithms presented herein are verified using data from measured indoor channels with variable antenna spacing and the results explained using measured radiation patterns for a two-element array. It is shown that for a two-element array, the best among the proposed techniques provides SNR improvement of about 3 dB in a tightly spaced array (inter-element spacing of 0.1 wavelength at 2 GHz) typical of small wireless devices. Additionally, these techniques are shown to perform significantly better than a single antenna device in an indoor channel considering realistic values of latency and propagation errors.

• Journal of Biomedical Engineering Research
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• v.26 no.5
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• pp.331-335
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• 2005

The fusion technology of small sensor and wireless communication was followed by various application examples of the embedded system, where the social infrastructural facilities and ecological environment were wirelessly monitored. In addition, this technology represents the primary application area being extended into the healthcare field. In this study, a body area network for ubiquitous healthcare is presented. More specifically this represents a wireless biomedical signal acquisition device characterized by small size, low power consumption, pre-processing and archiving capability. Using this device, a new method for monitoring vital signs and activity is created. A PDA-based wireless sensor network enables patients to be monitored during their daily living, without any constraints. Therefore, the proposed method can be used to develop Activities of Daily Living (ADL) monitoring devices for the elderly or movement impaired people. A medical center would be able to remotely monitor the current state of elderly people and support first-aid in emergency cases. In addition, this method will reduce medical costs in society, where the average life expectancy is increasing.