• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.612-614
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• 1999

In order to improve the operational reliability, it is necessary to validate the measured sensor data, isolate any failed sensor and recover the failed critical measurement. This paper describes the use of estimating equation to identify failed sensors and to recover the feedback signal for control purpose when the sensor measurement is determined to be erroneous Simulation results show that the proposed sensor validation scheme can adequately identify the failed sensor and provide reasonable estimates for control purposes.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.1 s.94
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• pp.167-173
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• 1999

This paper presents results of monitoring grinding processes with on-the-machine measurement of surface roughness by using nux ratios of scattered lights. A compact, on-the-machine surface roughness sensor. which consists of a diodelaser and several optic units. is developed. The control unit is also developed. The developed sensor together with the controller is applied for monitoring grinding processes of two different grinding machines. Experimental results show that the nux ratios and their standard deviations measured by the developed sensor over the entire ground surface are useful for monitoring grinding conditions. In particular, the sensor and the control unit are proved to be useful for monitoring grinding processes in order to detect abnormal grinding conditions and dressing time.

• Smart Structures and Systems
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• v.10 no.3
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• pp.299-312
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• 2012

The authors' research efforts recently led to the development of a customized wireless control unit which receives the real-time feedbacks from the sensors, and elaborates the consequent control signal to drive the actuator(s). The controller is wireless in performing the data transmission task, i.e., it receives the signals from the sensors without the need of installing any analogue cable connection between them, but it is powered by wire. The actuator also needs to be powered by wire. In this framework, the design of a power management unit is of interest only for the wireless sensor stations, and it should be adaptable to different kind of sensor requirements in terms of voltage and power consumption. In the present paper, the power management efficiency is optimized by taking into consideration three different kinds of accelerometers, a load cell, and a non-contact laser displacement sensor. The required voltages are assumed to be provided by a power harvesting solution where the energy is stored into a capacitor.

• Journal of Sensor Science and Technology
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• v.20 no.2
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• pp.107-113
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• 2011

LSPR(Localized Surface Plasmon Resonance) sensor measures the refractive index change on the sensor surface. The detection of biological reaction with the unknown refractive index needs to be converted into the signal sensitivity for the refractive index change for comparison with other measurements. To find the signal sensitivity, the three steps of signal processing are proposed, which are signal modeling, signal calibration and signal normalization of LSPR sensor. The detected signal of biotin-streptavidin interaction has been converted into unit of [RU](Resonance Unit) using the proposed method. The converted signal directly can be compared with the other sensors including commercialized one.

• Journal of the Society of Disaster Information
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• v.5 no.1
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• pp.122-139
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• 2009

USN Middleware plays roles of broker between sensors and applications. It collects sensor data, decides the situation and sends the result to the applications. It is not good to decide the situation from one sensor data, because it may error data or reflect small part of all. In this paper, we propose the disaster management model based on the concept 'group' and 'semantic information' from the sensing data. Group is the primary unit to decide the situation. It consists of several sensors which were installed in the same place and had the same pre-defined condition to act. For example, all fire sensors in the room simultaneously trigger the ring when the same pre-defined temperature is recorded. Then, the all fire sensors are included to the same one sensor group. All operations of the intelligent USN middleware are based on the 'group' unit. Disaster information is the result of the interpretation of the sensing data. based on the 'group', the disaster meaning is processed.

• Journal of Power Electronics
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• v.5 no.1
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• pp.62-66
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• 2005

A simple fault correction method for rotor position detection of a brushless DC(BLDC) motor with trapezoidal back EMF(electromotive force) using a Hall effect latch unit is presented. The reason why the Hall effect latch unit does not operate properly during the startup of a BLDC motor is thoroughly explained. To solve this problem, a simple code change method and its hardware implementation issues are proposed and discussed.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.05a
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• pp.22-27
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• 2000

This Paper decribes a monitoring system using Modbus protocol and RS485 interface applied in many industrial field. We developed hardware to receive alanlog sensor output and monitoring program to communicate with hardware and carried out experiment with potentiometer for plan sensor, . Through online communication between Master and Slaves we convinced the usage of this systems. Also plant data file that saved in Excel format is convenient in writing various typs of documents.

• Journal of Mechanical Science and Technology
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• v.18 no.4
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• pp.640-648
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• 2004

This paper describes a new magnetization method for non-destructive testing with magneto-optical sensor (denoted as MO sensor) which have the following characteristic : high observation sensitivity, independence of the crack orientation, and precise imaging of a complex crack geometry such as multiple cracks. When a magnetic field is applied normally to the surface of a specimen which is significantly larger than its defects, approximately the same magnetic charge per unit area occurs on the surface of the specimen. If there is a crack in the specimen, magnetic charge per unit area has the same value at the bottom of the crack. The distribution of the vertical component of the magnetic flux density, B$\_$Z/, is almost uniform over the no-crack area (denoted as B$\_$Z,BASE/), while the magnetic flux density is smaller in the surroundings of the crack(denoted as B$\_$Z,CRACK/) If B$\_$Z, BASE/ is a bit larger than the saturated magnetic flux density of the MO sensor (B$\_$s/) , then small magnetic domains occur over the crack area and a large domain over the non-crack area because B$\_$Z,CRACK/ is smaller than B$\_$s/.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.5
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• pp.287-291
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• 2010

In this paper, we designed and implemented mobile object automatic system based on senor networks for telematics. For developing this system, we gather the various sensing data through wireless communication method using zigbee sensor networks and analyze them in monitoring equipment. And we enable the driver to recognize the car state information on the whole by interfacing analyzed data to telematics unit. And, we implemented automatic controller that can control temperature and humidity in car automatically by actuating air conditioner based on the data that was monitored throughout temperature sensor, humidity sensor and brightness sensor based on sensor networks.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1813-1819
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• 2013

Existing level crossing obstacle detecting system was installed using a laser beam. Level crossing obstacle detecting system using a laser beam that has been a problem in relation to safety and maintainability failure according to weather conditions. We proposed laser radar level crossing obstacle detecting system as a way to overcome problem, and we developed an algorithm for this. Level crossing obstacle detecting system using a laser radar sensor algorithm is robust to external environment and a shadow zone does not exist. Sensor part of the laser radar level crossing obstacle detecting system of these is made up by the image processing unit and laser radar sensor, it operations by receiving train entering information from the control unit. In this paper, we proposed a detecting algorithm with calculation of the size of the laser radar sensor. Based on this, we were performance test on the basis of the scenario by making a prototype. In the future, laser radar level crossing obstacle detecting system to ensure the safety and reliability through the field test.