• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.3
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• pp.143-151
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• 2016

In this paper, a real-time air quality monitoring system based on wireless network is designed and implemented for industrial park or multiuse facilities. The existing gas detector is high price and hard to apply the remote monitoring system. On the other hand, demand for air quality monitoring is increasing because of industrial gas accident, air pollution, and so on. In Korea, indoor air regulation was established by law. According to indoor air regulation, CO2, CO, and NO2 are important gases as the air quality standard. So we study the gas detector for indoor air quality and the wireless network system. The wireless network consist of sensor network and WCDMA to apply various place. To verify the performance of the implemented gas detector, the gas measurement experiment is performed in laboratory environment by using the realized gas detecting wireless sensor node. And we evaluate the experiment results.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.6
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• pp.381-390
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• 2015

The efficient design of a transport protocol contributes to energy conservation as well as performance improvement in wireless sensor networks (WSNs). In this paper, a node-density-aware transport protocol (NDTP) for intra-cluster transmissions in WSNs for monitoring physical attributes is proposed, which takes node density into account to mitigate congestion in intra-cluster transmissions. In the proposed NDTP, the maximum active time and queue length of cluster heads are restricted to reduce energy consumption. This is mainly because cluster heads do more works and consume more energy than normal sensor nodes. According to the performance evaluation results, the proposed NDTP outperforms the conventional protocol remarkably in terms of network lifetime, congestion frequency, and packet error rate.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.2
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• pp.75-80
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• 2014

Energy consumption of sensor nodes is minimized because it has limited energy generator in wireless sensor network. Electronic shelf label system is one of application fields using wireless sensor networks. Battery size of small apparatus for displaying price is restricted. Therefore its current consumption have to be minimized. Furthermore the method for minimization of peak current would be considered because life cycle of coin battery used to display or RF is vulnerable to intensity of drain current. In this paper, we analyze current consumption pattern of low-power electronic shelf label system. Then we propose the method for minimization of current consumption by modification of software and hardware. Current consumption of the system using proposed method are approximately 15 to 20 percent lower than existing system and the life cycle of the system is approximately 10 percent higher than existing system.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.3
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• pp.103-111
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• 2009

Software update has been regarded as one of fundamental functions in wireless sensor networks. It can disseminate a delta-image between a current software image operating on a sensor node and its new image in order to reduce an update image(transmission data) size, resultantly saving energy. In addition, code-banking capability of micro-controllers can decrease the update image size. In order to maximize the efficiency of the software update, the proposed scheme exploits both the delta-image and the code-banking at the same time. Besides, it additionally delivers a recovery delta-image to properly handle abnormal conditions, such as message corruptions and unexpected power-off during the update.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.4
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• pp.193-203
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• 2014

This paper implements a weather monitoring system based on wireless sensor network. The wireless sensor network protocol proposed in this paper adopts a TDMA styled MAC. The protocol is designed to balance the energy consumption among sensor nodes. Other purposes of the protocol are to avoid the hidden terminal problem in 2-hop star topology, and to allow a CSMA styled communication in a given time slot to support emergent messages. Also, this paper develops the hardware of sensor node, gateway and electric generator based on solar and windy energy. The test results on the implemented system show that the time slot of each node is shifted in circular manner to balance the waiting time for transmission, and the reliability of wireless communication is over 99%.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.465-468
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• 2003

In industry areas, a lot of factories and process plants need network for processing data acquired from field and for communicating between sensors or actuators or field controllers. Most of the industry networks are based on wired solutions. But, recently, a lot of factories and process plants are moving into wireless solutions since they have some advantages compared with wired one. In this paper we first review the characteristics of wired and wireless network technologies and introduce the new technique called wireless sensor network (WSN). And then we describe the wireless sensor node system designed by us for WSN which has the ability of small size, flexibility and low-power consumption and embedded into the Bar-code scanner to communicate each other. Finally, we conclude this paper by showing that wireless industry network can be constructed with wireless sensor network without large change of traditional wired topologies through experiment using wireless sensor nodes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.67-74
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• 2009

In this paper, we constructed Embedded web-server to be monitored and controlled for intelligent vehicle on the base of embedded system and Zigbee wireless communication. By interfacing main controller and embedded system with ECU including every information of vehicle, it is possible to monitor the cruising information of vehicle, and sensor signal added to inside and outside of vehicle is transferred to embedded system through Zigbee communication. Web-server is constructed using embedded system, that's why the access to vehicle is possible using PC or mobile instrument, and the real-time check and control of vehicle is possible as well.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.6
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• pp.369-376
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• 2011

Since wireless sensor networks generally have the capability of network recovery, malfunction of a few sensor nodes in a sensor network does not cause a crucial problem paralyzing the sensor network. The malfunction of the sink node, however, is critical. If the sink node of a sensor network stops working, the data collected by sensor nodes cannot be delivered to the gateway because no other sensor nodes can take the place of the sink node. This paper proposes a TDMA-based wireless sensor network equipped with dual sink nodes, with a view to preventing data loss in the case of malfunction of a sink node. A secondary sink node, which synchronizes with a primary sink node and receives data from other sensor nodes in normal situations, takes the role of the primary sink node in the case of malfunction of the primary sink, thereby eliminating the possibility of data loss. The effectiveness of the proposed scheme is demonstrated through experiments.

• Smart Structures and Systems
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• v.3 no.3
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• pp.321-340
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• 2007

Structural control technologies have attracted great interest from the earthquake engineering community over the last few decades as an effective method of reducing undesired structural responses. Traditional structural control systems employ large quantities of cables to connect structural sensors, actuators, and controllers into one integrated system. To reduce the high-costs associated with labor-intensive installations, wireless communication can serve as an alternative real-time communication link between the nodes of a control system. A prototype wireless structural sensing and control system has been physically implemented and its performance verified in large-scale shake table tests. This paper introduces the design of this prototype system and investigates the feasibility of employing decentralized and partially decentralized control strategies to mitigate the challenge of communication latencies associated with wireless sensor networks. Closed-loop feedback control algorithms are embedded within the wireless sensor prototypes allowing them to serve as controllers in the control system. To validate the embedment of control algorithms, a 3-story half-scale steel structure is employed with magnetorheological (MR) dampers installed on each floor. Both numerical simulation and experimental results show that decentralized control solutions can be very effective in attaining the optimal performance of the wireless control system.

• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.5
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• pp.209-217
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• 2012

In the present, Wireless Sensor Network(WSN) has been used for the purpose of the military operation with surveillance systems and for collecting useful information from the natural environment. Basically, low-power, easy deployment and low cost are the most important factors to be deployed for WSNs. Lots of researches have been studied to meet those requirements, especially on the node capacity and battery lifetime improvements. Recently, the study of wireless mesh networks applied into the surveillance systems has been proceeded as a solution of easy deployment. In this paper, we proposed large-scale intelligent multi-layer surveillance systems based on QoS assuring Wireless Mesh Networks and implemented them in the real testbed environment. The proposed system explains functions and operations for each subsystem as well as S/W and H/W architectures. Experimental results are shown for the implemented subsystems and the performance is satisfactory for the surveillance system. We can identify the possibility of the implemented multi-layer surveillance system to be used in practice.