• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.585-590
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• 2012

In this paper, a system using vibrating wire sensor and zigbee wireless network has been implemented to monitor and manage the structure. The implemented strain controller drives vibrating wire sensor and computes strain from measuring frequency of the output signal. Temperature sensor is included to compensate strain by temperature. Using two axis acceleration sensor of strain controller can measure the direction of strain or deformation. To measure strain more effectively, wired and wireless communication function is included in this device. As results of experiments, it is shown that the developed system can be effectively applied to measure strain of the structure.

• Journal of Sensor Science and Technology
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• v.19 no.5
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• pp.342-348
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• 2010

The wireless sensor networks have been extensively researched. One of the issues in wireless sensor networks is a developing energy-efficient clustering protocol. Clustering algorithm provides an effective way to extend the lifetime of a wireless sensor networks. In this paper, we proposed an energy efficient clustering scheme by adjusting group size. In sensor network, the power consumption in data transmission between sensor nodes is strongly influenced by the distance of two nodes. And cluster size, that is the number of cluster member nodes, is also effected on energy consumption. Therefore we proposed the clustering scheme for high energy efficiency of entire sensor network by controlling cluster size according to the distance between cluster header and sink.

• Journal of the Korea Society of Computer and Information
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• v.11 no.6 s.44
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• pp.143-150
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• 2006

In this paper, we have implemented a ubiquitous healthcare system that can measure and check the blood pressure of human in anytime and anywhere. The implemented prototype are composed of blood pressure measurement terminal, data gathering base node, and medial information server. The implemented node constructs a sensor network using the Zigbee protocol and is ported the TinyOS. The data gathering base node is linux-based node that can transfer a sensed medial data through wireless LAN. And, the medical information server stores the processed medical data and can promptly notify the urgent status to the connected medical team. Through experiment, we confirmed the possibility of ubiquitous healthcare system based on sensor network using the Zigbee.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.3
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• pp.346-350
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• 2010

Since sensor nodes have restriction of using resources in Zigbee network, number of study on improving efficiency is currently ongoing[1]. Clustering mechanism based on hierarchy structure provides a prevention of duplicated information and a facility of a network expansion[2]. however overheads can occurs when the cluster header is elected and the election of a incorrect cluster header causes to use resources inefficiently. In this paper, we propose that the cluster header election mechanism using distances between nodes and density of nodes in accordance with the operation of the central processing system in which the sync nodes are having information of location and energy with respect to general nodes based on hierachy clustering mechanism.

• The Journal of the Korea Contents Association
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• v.10 no.1
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• pp.27-36
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• 2010

In wireless networks environment, there are attempts for constructing systems through which we can monitor and control various electronic devices used in large buildings at remoteness by using Zigbee protocol. Since address assignment method of DAA in Zigbee has a depth restriction, we cannot construct a network in large buildings. And also communication failures are frequent in a large network since broadcast storm can be occurred due to frequent broadcasts among a lot of nodes at AODV routing used in Zigbee. In order to solve these problems, in this paper, we propose a novel protocol which has improved the restriction of depth by using a fixed address assignment method, and has enhanced the broadcast occurrence by devising a static routing method to a packet movement between floors. Regardless of entire network, additionally, this was to enable internal communication reliably by composing an independent PAN. Specially, in this paper, we implemented the proposed wireless protocol and proved stability and practicality through experiment appliances of control of devices established in a large building.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.147-154
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• 2009

Lately, superhigh speed network infra is developing with the fast speed, is evolved by step that existent appliances are digitalised and appliances are become remote control by being gear to network. Also, gearing in Home network and superhigh speed network infra, control appliances in Internet and research that do monitering is proceed. Therefore, describe about indoor environment automatic control system that use Wireless sensor and Microcontroler in this paper. Because using that electric power, Zigbee sensor and Wireless module, embodied system that measured in the room temperature and use ATmega128 Microcontroler and use each device (temperature, illumination, humidity) back in house and control humidifier, electric fan etc. Can use variously in Home network field by this Wireless sensor and Microcontroler base, and also can apply variously to several industry fields as well as Home network field.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.7
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• pp.1302-1308
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• 2010

In this study, Zigbee Sensor Node to transmit harmful gases CO and $CO_2$ information using wireless communication within the ground and underground structures were developed. Wireless communication protocol was used Zigbee Stack included IEEE 802. 15.4 MAC protocol. For wireless transmission of detected harmful gas signal from ADC of MCU was implemented Zigbee Sensor Node that was developed protocol using Serial-Port-Profile(SPP) here. The proposed Zigbee Sensor Node was verified transmission distance from experiments. Transmission distance was into 90m in experiments. Distance experiments were measured at 10m intervals using sine & pulse wave input signal at indoors. The proposed Route Sensor Node was applied mesh routing protocol. When built up USN(Ubiquitous Sensor Network)using Route Sensor Node, transmission distance was not limited. On the experimental results, harmful gas values between direct measurements and USN measurements were consistent. The semiconductor CO sensor and N-DIR $CO_2$ sensor module as a harmful sensor was used. Therefore, the proposed Zigbee Sensor Node was verified about reliability and validity to build USN for transmission of harmful gas information.

• Journal of Korea Multimedia Society
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• v.17 no.12
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• pp.1461-1472
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• 2014

Recently, smart devices has been spreaded and the definition of RFID/USN(Radio Frequency Identification/Ubiquitous Sensor Network) technology has also extended. So, originally, human is an agent of communications but now, 'the things' are also an agent of communication. That is, Internet of Things(IoT). IoT is very big IT infra technology that is based on wire-wireless network technologies such as Bluetooth and Wi-Fi. However, in reality, IoT service that can provide various meaning and integrate smoothly is not appear yet. To solve these problems of IoT, we implemented Publish/Subscribe system, which operate in Zigbee based wireless sensor network by using MQTT-SN protocol. Moreover, this system can operate with combining MQTT system that is already existed in external Internet network so, extensibility and flexibility aspect is excellent. We show that possibility of IoT services that is combined between different heterogeneous network through the MQTT-SN.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.631-634
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• 2009

Recent advances in wireless communication, electronics, MEMS device, sensor and battery technology have made it possible to manufacture low-cost, low-power, multi-function tiny sensor nodes. A large number of tiny sensor nodes form sensor network through wireless communication. Sensor networks represent a significant improvement over traditional sensors, research on Zigbee wireless image transmission has been a topic in industrial and scientific fields. In this paper, we design a Zigbee wireless image sensor node and multimedia monitoring server system. It consists of embedded processor, memory, CMOS image sensor, image acquisition and processing unit, Zigbee RF module, power supply unit and remote monitoring server system. In the future, we will further improve our Zigbee wireless image sensor node and monitoring server system. Besides, energy-efficient Zigbee wireless image transmission protocol and interworking with mobile network will be our work focus.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.4
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• pp.430-436
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• 2014

This paper relates to the study about the street security light management system. The purpose of the wireless remote management system is to manage street security lights efficiently. The system is composed of three components like light controller, CDMA gateway and web based remote management server. The zigbee solution is adopted to make local wireless network between street security lights. The CDMA network is used for the wireless communication between street security light controller and the remote control center. The gateway to interconnect zigbee network and CDMA was designed with low power 32 bits Cortex M3 micro-controller. For the data communication between the management server and the gateway, SMS and socket based TCP streaming is used. The management server sends SMS to the gateway to deliver light control and management requests, and the gateway replies with the light controllers report via TCP streaming. By using both SMS and TCP streaming communication, it was verified that simple cost effective management is possible for street security lights. We tried real test for 95 street security lights in real environment during two months and analyzed the practical possibility for mass supply.