• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.41-48
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• 2008

The realization of a monitoring system for senior citizens living alone through wireless sensor network. Due to the recent advances in medical science, people live longer than ever before which accelerates the number of senior citizens. The high rate of the old people in population causes some changes in the form of families, which results in the increasing number of old people living by themselves. This also causes a lot of social problems concerning aging population. For example, people found a dead body of 83-year-old, who had lived alone, after he passed away a month before. There is a national monitoring service for the old people of their daily lives, but the application of such system is very limited. Considering this, the current paper focuses on the realization of a monitoring system for senior citizens living alone through wireless sensor network. The system consists of ZigBee sensor network, which is based on standard IEEE 802.15.4. and the system uses Tmote Sky sensor mote made by Moteive, which is installed with TinyOS. The circumstances information data will be saved on DB and a household will be monitored through a Webpage or Mobile.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.491-496
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• 2009

In this paper, we propose USN Protocol of Room Control with high efficiency and new routing techniques. I establish a network of cluster hierarchy structure under bases standard for IEEE 802.15.4 and another networks to manage each room use a control packet transmitted and The proposed protocol does not perform BroadCast over a network and transmits a packet to same layer to the destination and then passes the packet after doing searches. If a destination to be transmitted cannot be looked up, the protocol transmits AODV routing packet so that not only traffic load of a wireless network is decreased, but also efficient routing path can be obtained.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.20-28
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• 2007

Zigbee sensor network base on IEEE802.15.4 has local address of 2 byte on transmit packet data which is pick up the address for each sensor node. Sensor network is requested low power, low cost, many nodes at hues physical area. There for Zigbee is very good solution supporting for next Ubiquitous generation but the Zigbee sensor network has address allocation problem of each sensor node. Is established standard from Zigbee Alliance, to the address allocation method uses Cskip algorithm. The Cskip algorithm use the hazard which allocates an address must blow Hop of the maximum modification and child node number. There is to address allocation and from theoretically it will be able to compose a personal 65536 sensor nodes only actual with concept or space, only 500 degree will be able to compose expansion or the low Zigbee network. We proposed an address allocation method using coordinate value for Zigbee sensor network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.348-353
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• 2008

Despite the increasing popularity of wireless sensor network, indoor positioning using low power IEEE 802.15.4 compliant radio had attracted an interest of many researchers in the last decade. Old fashionable indoor location sensing information has been presented in dull and unpleasant 2D image standard. This paper focused on visualizing high precision 3 dimensional RSSI-based (received signal strength indication) spatial sensing information in an interactive virtual reality on PDA. The developed system operates by capturing and extracting signal strength information at multiple pre-defined reference nodes to provide information in the area of interest, thus updating user's location in 3D indoor virtual map. VRML (Virtual Reality Modeling Language) which specifically developed for 3D objects modeling is utilized to design 3D indoor environment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.257-264
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• 2007

In this paper, we have designed and fabricated a wide-band and high gain antenna which can integrate a standard of IEEE 802.1la$(5.15\sim5.25\;GHz,\;5.25\sim5.35\;GHz,\;5.725\sim5.825\;GHz)$. We inserted a parallel dual slot into a rectangular patch to have wide-band, and we offset an element of capacitance from the slot by using coaxial probe feeding method. We also designed a converter of $\lambda_g/4$ impedance with taper type line so that wide-band impedance can be matched easily. We finally designed structure with $2\times2$ array in order to improve the antenna gain, and the final fabricated antenna could have a good return loss(Return loss$\leq$-10 dB) and a high gain(over 13 dBi) at the range of $5.01\sim5.95\;GHz(B/W\doteqdot940\;MHz)$.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.273-279
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• 2014

In this paper, we propose a novel algorithm for three dimensional positioning system and implement a system over indoor wireless channel. A commercial modules are used for mobile and fixed nodes which are product of German company Nanotron Co. This module adopts chirp spread spreading scheme as modulation method to improve the ranging resolution and the module satisfies the IEEE standard 802.15.4a. The distance computation is based on received signal strength(RSS) levels and trilateration method. A testbed was set up to measure and compare the positioning estimation error of the proposed algorithm. The experiments results showed that the accuracy of location estimation was sufficiently good as much as 1m distance error in a wireless environment in an office building.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.244-247
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• 2016

Internet of Things spotlighted by the recent growth of the country: the interest in (IoT Internet pf Things) is being maximized. According to the scale of the 2013 Machina Research 2022 yireundago IoT market it is predicting about $ 1.2 trillion. Also the number of IoT devices connected simultaneously to the 2020 worldwide reached about 2.1 billion, and is expected to require about 200 million communications link. Many of these devices in order to manage and operate them efficiently IEEE 802.15.4e, D2D, Beacon, supporting protocols such as Zigbee gateway and network Connectivity to the urgent need for a proactive response to M2M -based operating convert it to a standard protocol being. This paper supports a variety of devices with different protocols and propose the design of intelligent Gateway with integrated features to manage operations.

• Journal of Digital Convergence
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• v.11 no.7
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• pp.201-207
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• 2013

The chirp signaling has been mainly used in radar systems due to its good correlation characteristics, and nowadays it is applied to real time locating system(RTLS). The RTLS with chirp signaling was chosen as a standard such as ISO/IEC 24730-5 and IEEE 802.15.4a. In this paper, the performance of a real time locating system with chirp signaling was evaluated and simulated with relative distance error rates. We considered three cases of S/I = -30[dB], -20[dB], and -10[dB] with Rician factor K=10 and K=20. The performance was enhanced with K factor improvement by 25%, 27% and 50% for respective three cases of S/I. As results, in case of S/I < -20[dB], the minimum signal power is required for performance improvement even though the line of sight component is helpful. And also, in case of S/I ${\geq}$ -20[dB], as the line of sight component is stronger the better performance is obtained.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.293-297
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• 2009

This paper describes a real-time reliable measurement and analysis system for ubiquitous healthcare based on IEEE802.15.4 standard. In order to obtain and monitor physiological body signals continuously, wearable pulse oximeter is designed in wrist that could used to measure oxygen saturation of a patient unobtrusively. The measured data was transferred to a central PC or server by using wireless sensor nodes via a wireless sensor network for storage and analysis purposes. LabVIEW server program was designed to monitor and process the measured photoplethysmogram(PPG) to accelerated plethysmogram(APG) by appling second order derivatives in server PC. These experimental results demonstrate that APG can precisely describe the features of an individual's PPG and be used as estimation of vascular elasticity for blood circulation.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2444-2452
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• 2022

The field-programmable gate array (FPGA) is gaining popularity in industrial automation such as nuclear power plant instrumentation and control (I&C) systems due to the benefits of having non-existence of operating system, minimum software errors, and minimum common reason failures. Separate functions can be processed individually and in parallel on the same integrated circuit using FPGAs in comparison to the conventional microprocessor-based systems used in any plant operations. The use of FPGAs offers the potential to minimize complexity and the accompanying difficulty of securing regulatory approval, as well as provide superior protection against obsolescence. Wireless sensor networks (WSNs) are a new technology for acquiring and processing plant data wirelessly in which sensor nodes are configured for real-time signal processing, data acquisition, and monitoring. ZigBee (IEEE 802.15.4) is an open worldwide standard for minimum power, low-cost machine-to-machine (M2M), and internet of things (IoT) enabled wireless network communication. It is always a challenge to follow the specific topology when different Zigbee nodes are placed in a large network such as a plant. The research article focuses on the hardware chip design of different topological structures supported by ZigBee that can be used for monitoring and controlling the different operations of the plant and evaluates the performance in Vitex-5 FPGA hardware. The research work presents a strategy for configuring FPGA with ZigBee sensor nodes when communicating in a large area such as an industrial plant for real-time monitoring.