• Journal of Korea Spatial Information System Society
• /
• v.11 no.2
• /
• pp.1-6
• /
• 2009

Localization of nodes is a key technology for application of wireless sensor network. Having a GPS receiver on every sensor node is costly. In the past, several approaches, including range-based and range-free, have been proposed to calculate positions for randomly deployed sensor nodes. Most of them use some special nodes, called anchor nodes, which are assumed to know their own locations. Other sensors compute their locations based on the information provided by these anchor nodes. This paper uses a single mobile anchor node to move in the sensing field and broadcast its current position periodically. We provide a weighted centroid localization algorithm that uses coefficients, which are decided by the influence of mobile anchor node to unknown nodes, to prompt localization accuracy. We also suggest a criterion which is used to select mobile anchor node which involve in computing the position of nodes for improving localization accuracy. Weighted centroid localization algorithm is simple, and no communication is needed while locating. The localization accuracy of weighted centroid localization algorithm is better than maximum likelihood estimation which is used very often. It can be applied to many applications.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2011.06a
• /
• pp.1283-1284
• /
• 2011

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.682-684
• /
• 2007

This paper deals the application of sensor network system to fabricate wireless nodes. This node includes a CPLD(XC2C256), FPGA(XC3S1000) a RF module(Bim-433-F), a Hall Sensor and I also develop the CPLD(EPGA) controlling with Verilog-HDL using ISE. The network was consisst of a PC, a Sink node as a gateway, and three Sensor nodes. This sensor network can reaches 40 m with RF interface using by multi-path network.

• Journal of Ocean Engineering and Technology
• /
• v.24 no.3
• /
• pp.1-10
• /
• 2010

In this study, hybrid smart sensor nodes were developed for the autonomous structural health monitoring of prestressed concrete (PSC) girders. In order to achieve the objective, the following approaches were implemented. First, we show how two types of smart sensor nodes for the hybrid health monitoring were developed. One was an acceleration-based smart sensor node using an MEMS accelerometer to monitor the overall damage in concrete girders. The other was an impedance-based smart sensor node for monitoring the local damage in prestressing tendons. Second, a hybrid monitoring algorithm using these smart sensor nodes is proposed for the autonomous structural health monitoring of PSC girders. Finally, we show how the performance of the developed system was evaluated using a lab-scaled PSC girder model for which dynamic tests were performed on a series of prestress-loss cases and girder damage cases.

• KIPS Transactions on Computer and Communication Systems
• /
• v.4 no.1
• /
• pp.11-14
• /
• 2015

WSN (Wireless Sensor Network) based on low-power is one of the core technologies in the ubiquitous society. In this paper, we present a border surveillance and control system in WSN environment. The system consists of static sensor node, mobile sensor node, static gateway, mobile gateway, server and mobile application. Mobile applications are divided into user mode and manager mode. So users monitor border surveillance through mobile phone and get information of border network environment without time and space constraints. In manager mode, for the flexible operation of nodes, manager can update to the software remotely and adjust the position of the mobile node. And also we implement a suitable multi-hop routing protocol for scalable low-power sensor nodes and confirm that the system operates well in WSN environment.

• Journal of the Korea Society for Simulation
• /
• v.23 no.2
• /
• pp.65-72
• /
• 2014

Sensor nodes are easily compromised by attacker when which are divided in open environment. The attacker may inject false report and false vote attack through compromised sensor node. These attacks interrupt to transmission legitimate report or the energy of sensor node is exhausted. PVFS are proposed by Li and Wu for countermeasure in two attacks. The scheme use inefficiency to energy of sensor node as fixed report threshold and verification node. In this paper, our propose the next neighbor node selection scheme based on fuzzy logic system for energy improvement of PVFS. The parameter of fuzzy logic system are energy, hops, verification success count, CH select high the next neighbor node among neighbor nodes of two as deduction based on fuzzy logic system. In the experimental, our proposed scheme was improvement to energy of about 9% compare to PVFS.

• Journal of Advanced Navigation Technology
• /
• v.14 no.3
• /
• pp.384-390
• /
• 2010

Since many accidents have been constantly occurring in the workplace, requirements of Industrial Safety Management have also been increasing. In order to meet the needs and prevent the problems in advance, we designed wireless sensor network system based on PLC. This system is set with amain node including PLC Modem and Zigbee in the every workplace and each wireless sensor node is attached to every worker in the workplace. The main node is supposed to transmit and receive sensor data, and the data which is from a wireless sensor node to the main node is delivered to monitoring PC through PLC. In this paper, it is expected that, by perceiving the realtime situation of the work place through this system, we could prevent the problems in advance and reduce damages by accidents.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.10a
• /
• pp.518-521
• /
• 2007

The functional wireless sensor node for u-healthcare application was developed. The developed sensor node can check the abnormality of ECG in some simple software in ROM of microprocess in the sensor node. The ECG signal is one of very important health signal form human body, and wavelike signal which is sampled as a sampling frequency between 100 and 400 Hz for digitalization, so the wireless data dor ECG signal is some heavy in Zigbee communication. Thus the sensor send the ECG signal to other sensor nodes or base station when it find abnormality in ECG signal is key technology to reduce the traffic between sensor nodes in wireless sensor network for u-healthcare, The sensor node does not need to transmit ECG data all time in wireless sensor network and to server. Using these sensor nodes, the healthcare system can dramatically reduce wireless data packet overload, the power consumption of battery in the sensor nodes and thus increase the reliability of the wireless system.

• The Journal of the Korea Contents Association
• /
• v.8 no.1
• /
• pp.186-194
• /
• 2008

This paper has implemented a ubiquitous healthcare system that can measure and check the electrocardiogram of a human body in anytime and anywhere. The implemented prototype is composed of electrocardiogram measurement terminal, data gathering base node, and medical information server. The implemented node constructs a sensor network using the Zigbee protocol and the TinyOS is installed on each node. The data gathering base node is linux-based node that can transfer 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 Environmental Science International
• /
• v.17 no.1
• /
• pp.77-83
• /
• 2008

The purpose of this study was to develop the national park visitor counting system using the ubiquitous sensor network. This system is composed of a sensor node, sink node, gateways, CDMA module, server, and clients. The results of the study were: 1) stable data transmission distance was possible within 100 meters between sensor nodes, 2) the developed counting sensor system showed a network communication stability level of 88.3 percent in 1.2m wide trails. When installed in concentrate use areas or forks of national parks, the visitor counting system will not only contribute to provide reliable visitor counting, but also to improve the quality of national park visitor service, to manage park facilities and natural resources more efficiently, to achieve an information oriented national park system.