• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.197-202
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• 2016

In this paper, we propose optimal smart home security monitoring system. Proposeed optimal smart home security system using the three types of ultrasonic sensors were tested to obtain reliable data. and Using Raspberry Pi3, the smart home security system was implemented. In addition, It was verified through experiments optimal efficiency with a small amount compared to the conventional sensor of the home security system by the two ultrasonic sensors located in the optimal position. It was able to use two ultrasonic sensors to determine whether the intruder's highly efficient and reliable intrusion, and connect the servo motor at the bottom of the camera so you can shoot adjusted to the attacker's location to shoot the intruder's image. In addition, by using a Web server and stored the recorded image and two ultrasonic sensor data and provide a Web page for a user to monitor at all remote locations.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.374-382
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• 2020

Purpose: Recently, structural defects in old safety management facilities have led to the collapse of buildings and facilities. The purpose of this study is to develop guidelines for the installation of regular monitoring systems that determine the optimal sensor location for monitoring exhibition space building sensors equipped with visual elements in order to analyze the risk signs of exhibition space buildings and develop measurement technology. Method: The components, installation locations, alarm criteria, and management measures of the instrument are presented. Result: A measure was proposed to determine the location of sensors, secure signal processing technology for analysis by having unified visual perception, and configure optimal 'risk sign detection' based on sensor monitoring through test-bed operation. Conclusion: The results of this study can be prepared against the disasters that may arise from the collapse of exhibition buildings, and contribute to strengthening safety management capabilities.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.2
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• pp.145-155
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• 2002

It is essential for health monitoring of a cable-stayed bridge to provide more accurate and enough information from the sensors. In experimental modal testing, the chosen measurement locations and the number of measurements have a major influence on the quality of the results. The choice is often difficult for complex structures like a cable-stayed bridge. It is extremely important a cable-stayed bridge to minimize the number of sensing operations required to monitor the structural system. In order to obtain the desired accuracy for the structural test, several issues must take into consideration. Two important issues are the number and location of response sensors. There are usually several alternative locations where different sensors can be located. On the other hand, the number of sensors might be limited due to economic constraints. Therefore, techniques such as methodologies, algorithms etc., which address the issue of limited instrumentation and its effects on resolution and accuracy in health monitoring systems are paramount to a damage diagnosis approach. This paper discusses an optimum sensor placement criterion suitable to the identification of structural damage for continuous health monitoring. A Kinetic Energy optimization technique and an Effective Independence Method are analyzed and numerical and theoretical issues are addressed for a cable-stayed bridge. Its application to a cable-stayed bridge is discussed to optimize the sensor placement for identification and control purposes.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.197-203
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• 2010

The problem of location awareness in wireless sensor networks where nodes use GPS (Global Positioning System), remains challenging problem, when considering the required large energy consumption during the localization phase. In this paper we designed hardware for GPS based localization and propose a framework, called ELS, to consume low cost energy. In the ELS framework, sensor nodes are equipped with GPS. Because GPS spends large energy for position awareness, conventional localization algorithms cannot use GPS-device. We try to find a solution for efficient energy expenditure of GPS. Finally, we derive optimal transmission power of GPS data and a scheme of localization through experiment and simulation.

• Proceedings of the KOSOMBE Conference
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• v.1994 no.05
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• pp.88-91
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• 1994

We develope a assistant system of foot pressure distribution for improvement gait Pattern, adapted working speed, and minimitation of muscle fatigue of the sensory feedback type FES system(SEFES). This measurement system consist of mat type pressure sensor with piezo electric films. The pressure data signal multiflexed input scanning method processed A/D conversion after two step amplify and integrate. Matrix sensor interface to PC for pseudo color display by level of Pressure distribution data. This measurement system clinically evaluated in hemiplegic patients. It has produced acceptable results with optimal location of the food sensor's pressure point and avoid the muscle fatigue.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.2
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• pp.69-78
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• 2009

Localization is a very important technique for the mobile robot to navigate in outdoor environment. In this paper, the development of the sensor fusion algorithm for controlling mobile robots in outdoor environments is presented. The multi-sensorial dead-reckoning subsystem is established based on the optimal filtering by first fusing a heading angle reading data from a magnetic compass, a rate-gyro, and two encoders mounted on the robot wheels, thereby computing the dead-reckoned location. These data and the position data provided by a global sensing system are fused together by means of an extended Kalman filter. The proposed algorithm is proved by simulation studies of controlling a mobile robot controlled by a backstepping controller and a cascaded controller. Performances of each controller are compared.

• Structural Engineering and Mechanics
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• v.13 no.2
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• pp.117-134
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• 2002

This paper presents a computational method for a confidence region of identified parameters which are affected by measurement noise and error contained in prescribed parameters. The method is based on sensitivities of the identified parameters with respect to model parameter error and measurement noise along with the law of error propagation. By conducting numerical experiments on simple models, it is confirmed that the confidence region coincides well with the results of numerical experiments. Furthermore, the optimum arrangement of sensor locations is evaluated when uncertainty exists in prescribed parameters, based on the concept that square sum of coefficients of variations of identified results attains minimum. Good agreement of the theoretical results with those of numerical simulation confirmed validity of the theory.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.4
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• pp.27-34
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• 2016

A new algorithm for determining optimal accelerometer locations is proposed by using a frequency-domain Hankel matrix which is much simpler to construct than a time-domain Hankel matrix. The algorithm was examined through simulation studies by comparing the outcomes with those from other available methods. To compare and analyze the results from different methods, a dynamic analysis was carried out under seismic excitation and acceleration data were obtained at the selected optimal sensor locations. Vibrational amplitudes at the selected sensor locations were determined and those of all the other degrees of freedom were determined by using a spline function. MAC index of each method was calculated and compared to look at which method could determine more effective locations of accelerometers. The proposed frequency-domain Hankel matrix could determine reasonable selection of accelerometer locations compared with the others.

• Smart Structures and Systems
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• v.19 no.3
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• pp.299-307
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• 2017

The magneto-electro-elastic (MEE) material under thermal environment exhibits pyroelectric and pyromagnetic coefficients resulting in pyroelectric and pyromagnetic effects. The pyroelectric and pyromagnetic effects on the behavior of multiphase MEE sensors bonded on top surface of a mild steel beam under thermal environment is presented in this paper. The aim of the study is to find out how samples having different volume fractions of the multiphase MEE composite behave in sensor applications. This is studied at optimal location on the beam, where the maximum electric and magnetic potentials are induced due to pyroelectric and pyromagnetic effects under clamped-free and clamped-clamped boundary conditions. The sensor which is bonded on the top surface of the beam is modeled using 8-node brick element. The MEE sensor bonded on mild steel beam is subjected to uniform temperature rise of 50K. It is assumed that beam and sensor is perfectly bonded to each other. The maximum pyroelectric and pyromagnetic effects on electric and magnetic potentials are observed when volume fraction is ${\nu}_f=0.2$. The boundary conditions significantly influence the pyroelectric and pyromagnetic effects on electric and magnetic potentials.

• The Journal of the Acoustical Society of Korea
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• v.37 no.1
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• pp.53-59
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• 2018

In this study, a new design method is developed to optimize the structure of an underwater sparse array sensor. The purpose of this research is to design the structure of a sparse array that has the performance equivalent to a fully sampled array. The directional factor of a sparse planar array is derived as a function of the structural parameters of the array. With the derived equation, the structure of the sparse array sensor is designed to have the performance equivalent to that of the fully array sensor through structural optimization of the number and location of transmitting and receiving elements in the array. The designed sparse array sensor shows beam patterns very close to those of the fully array sensor in terms of PSLL (Peak Side Lobe Level) and MLBW (Main Lobe Beam Width), which confirms the effectiveness of the present optimal design method. Further, the validity of the analytic beam patterns is verified by comparing them with those from the FEA (Finite Element Analysis) of the optimized sparse array structure.