• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1515_1516
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• 2009

A 440MHz wireless and passive surface acoustic wave (SAW) based micro-sensor was developed for simultaneous measurement of temperature and humidity. The developed sensor is composed of a SAW reflective delay lines structured by an IDT (Inter-Digital Transducer), four reflectors and humidity sensitive film (polyimide). Polyimide was dry-ecthed by RIE (Reactive Ion Etching) to obtain high roughness, which gives the large reaction area resulting in high sensitivity. In wireless testing using a network analyzer, sharp reflection peaks with high S/N ratio, small signal attenuation, and few spurious peaks were observed in the time domain. High sensitivity towards the temperature and humidiy were also observed in the large concentration range. The obtained sensitivity was $16.8^{\circ}/^{\circ}C$ for temperature sensor and $15.8^{\circ}$/%RH for humidity sensor.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.174-177
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• 1995

Detecting a small threat object either fast moving or floating on shallow water presents a formidable challenge to shipboard sensor systems, which must determine whether or not to launch defensive weapons in a timely manner. An integrated multisensor concept is envisioned wherein the combined use of active and passive sensor is employed for the detection of short duration targets in dense ocean surface clutter to maximize detection range. The objective is to develop multisensor integration techniques that operate on detection data prior to track formation while simultaneously fusing contacts to tracks. In the system concept, detections from a low grazing angle search radar render designations to a sensor-search infrared sensor for target classification which in turn designates an active electro-optical sensor for sector search and target verification.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.3
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• pp.270-274
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• 2008

The microwave sensor in which the sensitivity was excellent and a structure is simple was developed and it manufactured. And the sensing range that uses the developed product was confirmed. When the developed microwave sensor was set up in the ceiling of a building, we confirmed that the amplitude of the sensitive area increased as the tilting angle was enlarged. The sensitive area became a greatest in case the tilting angle was 65 degree. According to the height of a ceiling, because the sensing range is determined, in case of using in the building in which the height of a ceiling is enough secured it is determined to secure the more wide sensitive area. Moreover, the configuration of the circuit having the simple structure makes the miniaturization of a product, and the light weight possible. It is considered to have the price competitive power which it reduces the manufacturing cost, is sufficient.

• Journal of Sensor Science and Technology
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• v.26 no.3
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• pp.192-198
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• 2017

In this paper, we newly developed a passive transponder for visible light identification (VLID) using ultrasonic wave. The solar cell in the transponder receives the reader light and generates current for supplying power to the transponder circuit. At the same time the solar cell detects the interrogating signal in the visible light from the reader. The transponder recognizes the interrogating signal and generates the responding signal using ultrasonic wave. In experiments, we used 40 kHz ultrasonic wave for the responding signal from the transponder. The maximum read distance was about 3.4 m when the transponder was exposed to the reader light of 24W LED array.

• Journal of Sensor Science and Technology
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• v.24 no.4
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• pp.232-238
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• 2015

In this paper, we introduce a passive transponder in which an LED is used for both a light transmitter and a receiver, and a solar cell is used for supplying power to the all devices in the transponder. The LED in the transponder operates as a photodetector in the receiving mode, and acts as a light source in the transmitting mode. The current responsivity of the LED detector was measured to be in the order of $10^{-4}A/W$, and the receiving bandwidth with a load resistance of $10k{\Omega}$ was about 10 to 30 kHz. Using the LED for an optical transceiver in a VLID transponder, the detection range was about 70 cm when the transponder was illuminated by the visible light from a $3{\times}3$ LED array in a reader.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1204-1209
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• 2000

Many analytical and experimental studies on the active suppression of nonlinear panel flutter by using piezoceramic patch have been carried out. However, these active control methods have a few important problems; a large amount of power is required to operate actuators, and additional apparatuses such as sensor systems and controller are needed. In this study passive suppression schemes for nonlinear flutter of composite panel, which is believed to be more robust suppression system than active control in practical operation, are proposed by using piezoelectric inductor-resistor series shunt circuit. Toward the end, a finite element equation of motion for an electromechanically coupled system is proposed using the Hamilton's principle. To achieve the best damping effect, optimal shape and location of the piezoceramic(PZT) patches are determined by using genetic algorithms. The results clearly demonstrate that the passive damping scheme by using piezoelectric shunt circuit can effectively attenuate the flutter.

• Current Optics and Photonics
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• v.4 no.3
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• pp.186-192
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• 2020

This paper describes a real-time monitoring system in Ethernet passive optical networks (EPON) that uses burst-mode fiber Bragg grating (FBG) optical sensors. The FBG interrogation unit in the optical line terminal (OLT) transmits the monitoring wavelength to optical network units (ONUs). The FBG sensor unit in each ONU returns a burst-mode monitoring signal to the OLT. As the system applies time division multiple access (TDMA), a uniform Bragg wavelength can be used to monitor the EPON system. The FBG interrogation unit analyzes the received burst-mode monitoring signals and outputs fault information on the ONU branches in EPON. The simulation results show the effectiveness of the proposed monitoring system based on TDMA. In addition, we compared the proposed TDMA-based monitoring system with a WDMA-based monitoring system.

• Journal of the Semiconductor & Display Technology
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• v.21 no.4
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• pp.126-131
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• 2022

The number of joint disease patients is increasing every year. Currently, the most CPM(Continuous Passive Motion) equipment uses expensive imported equipment, and one CPM equipment is designed to be used only in one joint, medical personnel or hospitals who are the main users of the medical equipment need to have several types of CPMs for joint rehabilitation. To solve this problem, this paper designed a multifunctional joint medical equipment that enables rehabilitation of knee, shoulder, and elbow joints in one CPM equipment and includes general, intensive, and adaptive exercise functions for effective treatment according to the patient's condition. The patient's condition was diagnosed using a load cell and a current sensor. In this paper, effective rehabilitation methods were presented and high reliability and precision of medical equipment was confirmed through experiments using potentiometer, encoder, and PI controller.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.6
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• pp.697-703
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• 2009

Target Motion Analysis(TMA) means to detect target position, velocity and course for using passive sonar system with bearing-only measurement. In this paper, we apply the TMA algorithm for a submarine with Multi-Sensor Data Fusion(MSDF) and we will decide the best TMA algorithm for a submarine by a series of computer simulation runs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.447-450
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• 2010

SAW Device 라는 Passive 소자는 ID Tag나 소형센서들을 대체할 수 있는 MEMS 기술의 초소형 Device 다. 이 SAW Device를 이용하면 독립된 공간이나 전원이 필요한 센서 제어 등을 대신할 수 있을 것이다. 이렇게 활용범위가 확대됨에 따라 다양한 SAW Device를 사용하기 위한 플랫폼이 요구된다. 하지만 현재 SAW Sensor는 많은 발전을 해왔지만 SAW Sensor를 활용할 수 있는 플랫폼의 발전은 미흡하기 때문에 본 논문에서는 이러한 SAW Device를 측정할 수 있는 SAW Reader를 FPGA를 이용하여 좀 더 간단하고 효율적인 Reader platform을 구현해 보고자 한다.