• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.127-132
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• 2008

As economic rapid growth, large structures are damaged by defects from design and construction process of the formation and environments. Therefore, safety diagnosis and monitoring skills are bringing importance into relief and legislate for safety diagnosis of large structures. However, the existing monitoring systems are difficult by using wire cable because of cost, error of date, location, revise. In this paper, wireless sensor network which are accelerator, temperature sensor system using ubiquitous had been field test on Sea-Hea Grand bridge. We compare accelerator, temperature sensor system with wire and wireless sensor network.

• Journal of Korea Multimedia Society
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• v.15 no.10
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• pp.1228-1235
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• 2012

In this Paper, we propose an energy efficient localization technique based on WUSB (Wireless USB) over WBAN (Wireless Body Area Networks) protocol required for Wearable Computer systems. For this purpose, the proposed localization algorithm minimizes power consumption and estimates location without range information. It is executed independently on the basis of WUSB over WBAN protocol at each sensor node comprising peripherals of a wearable computer system. And it minimizes power consumption by estimating locations of sensor nodes with range-free method fast.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2453-2456
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• 2004

People want to control various facilities regardless location in ubiquitous era. Therefore we have a various devices embedded wireless functions. In this paper we implement a control program in a PDA that used Wireless LAN among wireless protocols. The objectives of this paper are: The first, to make a control program in server and a wireless client (PDA) using WLAN. The second, to implement smart home model. The third, to propose useful functions in home controls.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1199-1204
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• 2004

In this paper, the DCS (Data Communication System) which is a main part of CBTC (Communication Based Train Control) system is consisted of radio based wireless communication system and optical based wired system. In the radio based wireless communication, the location of AP(Access Point) Enclosure and Antenna shall be optimized for the guaranteed communication channel between wayside and trains either open aired or tunnelled area. This study is introducing the way of determinating optimized positioning the radio based wireless communication equipment in Bundang Line. At this moment, this CBTC project for the KNR's (Korea National Railway) intelligent train control system are in installment phase therefore the simulation data can show only from lab equipment. After the phase I testing, more detailed data can be collected and advanced paper will be issued in a short time.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1321-1326
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• 2008

According to the conventional train control system, the area of each train is detected by plural track circuits located in a constant distance on railway lines in order to control a distance between trains. The conventional train control system has the difficulty in making use of the substructure thoroughly and transmitting enormous amount of information. To solve those problems, the wireless CBTC system has been a global issue. To apply wireless CBTC system to train system, the following two requirements are preferentially necessary: (1) Dualizing wireless CBTC system to control trains ceaselessly in a system accident, (2) Improving dependency of transmitted information for location and velocity to protect collision and derailment of lightweight trains in advance.

• ETRI Journal
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• v.41 no.3
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• pp.326-336
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• 2019

A wireless power transfer technique can solve the power capacity problem in wireless rechargeable sensor networks (WRSNs). The charging strategy is a wide-spread research problem. In this paper, we propose a demand-based charging strategy (DBCS) for WRSNs. We improved the charging programming in four ways: clustering method, selecting to-be-charged nodes, charging path, and charging schedule. First, we proposed a multipoint improved K-means (MIKmeans) clustering algorithm to balance the energy consumption, which can group nodes based on location, residual energy, and historical contribution. Second, the dynamic selection algorithm for charging nodes (DSACN) was proposed to select on-demand charging nodes. Third, we designed simulated annealing based on performance and efficiency (SABPE) to optimize the charging path for a mobile charging vehicle (MCV) and reduce the charging time. Last, we proposed the DBCS to enhance the efficiency of the MCV. Simulations reveal that the strategy can achieve better performance in terms of reducing the charging path, thus increasing communication effectiveness and residual energy utility.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.565-581
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• 2019

This paper investigates the wireless powered two way relay network (WPTWRN), where two single-antenna users and one single-antenna relay firstly harvest energy from signals emitted by a multi-antenna power beacon (PB) and then two users exchange information with the help of the relay by using their harvested energies. In order to improve the energy transfer efficiency, energy beamforming at the PB is deployed. For such a network, to explore the performance limit of the presented WPTWRN, an optimization problem is formulated to obtain the achievable rate region bounds by jointly optimizing the time allocation and energy beamforming design. As the optimization problem is non-convex, it is first transformed to be a convex problem by using variable substitutions and semidefinite relaxation (SDR) and then solve it efficiently. It is proved that the proposed method achieves the global optimum. Simulation results show that the achievable rate region of the presented WPTWRN architecture outperforms that of wireless powered one way relay network architecture. Results also show that the relay location has significant impact on achievable rate region of the WPTWRN.

• Transactions of Materials Processing
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• v.32 no.6
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• pp.303-310
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• 2023

Electrohydraulic forming(EHF), one of the high-speed forming method, can supplement the weak point of previous forming process such as deep-drawing and electromagnetic forming. Indeed, EHF is time-consuming process during installing wire before experiment that hard to apply to industry. In this research, applying wireless electrode, the formability of SUS430 sheet was compared through EHF experiments using wire-installed electrode and the other, wireless. Although the power was a little lacking, the advantages of the experiment using wireless electrode could be confirmed with checking the optimal location of electrodes where the plasma is generated and comparing free-bulging height depending on former and later condition of electrodes with performing several single and multistage experiments for same voltage, 6 kV.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.8
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• pp.750-757
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• 2011

Wireless Sensor Network is composed of a lot of sensor nodes that are densely deployed in a field. So generally this sensor nodes are spreaded using Helicopter or Fixed wing. Each node delivers own location and acquired information to user when it detects specific events. In this paper, we propose localization algorithm without range information in wireless sensor network using helicopter. Helicopter broadcasts periodically beacon signal for sensor nodes. Sensor nodes stored own memory this beacon signal until to find another beacon point(satisfied special condition). This paper develops a localization mechanism using the geometry conjecture(perpendicular bisector of a chord) to know own location. And the simulation results demonstrate that our localization scheme outperforms Centroid, APIT in terms of a higher location accuracy.

• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.4
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• pp.1-8
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• 2008

The USN is important in technique, unmanned observation using wireless network camera, detection technique that use intrusion detection sensor. But these encrypted data transmission and processing technique through sensor network, method of the staff's location recognition and arrangement aren't serviced still as a integrated system in facility security industry. This paper proposed that improve facility management, the staff present recognition and system efficiency using RFID, USN and wireless camera.