• 한국전기전자재료학회논문지
• /
• 제32권6호
• /
• pp.472-476
• /
• 2019

We have proposed a novel planar lightwave circuit (PLC) optical sensor to monitor the contamination in a flow-cell where water is continuously supplied through a water quality measurement system. We designed a PLC chip with a V-shape waveguide and the simulated its function as a sensor for monitoring contamination in a flow-cell using a numerical the FDTD (finite-difference time-domain) analysis. A novel cross type of waveguide was introduced to make the PLC chip of the V-shaped waveguide. The fabricated PLC was cut into the cross waveguide. A change in the optical propagation loss of the PLC sensor was observed after immersing the PLC sensor into city water. It was determined that the propagation loss of the PLC sensor was 3 dB at a wavelength of $1.55{\mu}m$ in the city water for 15 days.

• Smart Structures and Systems
• /
• 제6권5_6호
• /
• pp.641-659
• /
• 2010

Structural Health Monitoring (SHM) gradually becomes a technique for ensuring the health and safety of civil infrastructures and is also an important approach for the research of the damage accumulation and disaster evolving characteristics of civil infrastructures. It is attracting prodigious research interests and the active development interests of scientists and engineers because a great number of civil infrastructures are planned and built every year in mainland China. In a SHM system the sheer number of accompanying wires, fiber optic cables, and other physical transmission medium is usually prohibitive, particularly for such structures as offshore platforms and long-span structures. Fortunately, with recent advances in technologies in sensing, wireless communication, and micro electro mechanical systems (MEMS), wireless sensor technique has been developing rapidly and is being used gradually in the SHM of civil engineering structures. In this paper, some recent advances in the research, development, and implementation of wireless sensors for the SHM of civil infrastructures in mainland China, especially in Dalian University of Technology (DUT) and Harbin Institute of Technology (HIT), are introduced. Firstly, a kind of wireless digital acceleration sensors for structural global monitoring is designed and validated in an offshore structure model. Secondly, wireless inclination sensor systems based on Frequency-hopping techniques are developed and applied successfully to swing monitoring of large-scale hook structures. Thirdly, wireless acquisition systems integrating with different sensing materials, such as Polyvinylidene Fluoride(PVDF), strain gauge, piezoresistive stress/strain sensors fabricated by using the nickel powder-filled cement-based composite, are proposed for structural local monitoring, and validating the characteristics of the above materials. Finally, solutions to the key problem of finite energy for wireless sensors networks are discussed, with future works also being introduced, for example, the wireless sensor networks powered by corrosion signal for corrosion monitoring and rapid diagnosis for large structures.

• 센서학회지
• /
• 제28권5호
• /
• pp.311-317
• /
• 2019

Rotating devices are commonly installed in power plants and factories. This study proposes a self-powered sensor node that is powered by converting the vibration energy of a rotating device into electrical energy. The self-powered sensor consists of a piezoelectric harvester for self-power generation, a rectifier circuit to rectify the AC signal, a sensor unit for measuring the vibration frequency, and a circuit to control the light emitting diode (LED) lighting. The frequency of the vibration source was measured using a piezoelectric-cantilever-type vibration frequency sensor. A green LED was illuminated when the measured frequency was within the normal range. The power generated by the piezoelectric harvester was determined, and the LED operation was assessed in terms of the vibration frequency. The piezoelectric harvester was found to generate a power of 3.061 mW or greater at a vibration acceleration of 1.2 g ($1g=9.8m/s^2$) and vibration frequencies between 117 and 123 Hz. Notably, the power generated was 4.099 mW at 122 Hz. As such, our self-powered sensor node can be used as a module for monitoring rotating devices, because it can convert vibration energy into electrical energy when installed on rotating devices such as air compressors.

• 한국건축시공학회지
• /
• 제23권1호
• /
• pp.69-79
• /
• 2023

본 연구에서는 역학변색센서를 활용한 건축물의 균열 모니터링 기술 개발에 관한 실험적 연구를 수행하였다. 콘크리트 시험체에 유도된 균열에 역학변색센서를 부착한 후 균열의 진행에 따른 변색 이미지를 촬영하였다. 그리고 센서의 변색 이미지 분석 결과와 균열 폭과의 관계식으로부터 균열 폭 도출 식을 제안하였다. 또한, 제안된 균열 폭 모니터링 기법의 검증을 통하여 건축물 균열 모니터링을 위한 역학변색센서의 활용 가능성을 확인하였다.

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
• /
• pp.810-819
• /
• 1993

An autonomous lan vehicle for agriculture(ALVA-II) was developed. A prototype vehicle was made by modifying a commercial tractor. A Navigation sensor system with a geo-magnetic sensor performed the autonomous operations of ALVA-II, such as rotary tilling with headland turnings. A navigation sensor system with a machine vision system was also investigated to control ALVA-II following a work boudnary.

• 반도체디스플레이기술학회지
• /
• 제8권4호
• /
• pp.21-24
• /
• 2009

We investigated a nanoscale inertia sensor based on telescoping carbon nanotubes, using classical molecular dynamics simulations. The position of the telescoping nanotubes is controlled by the centrifugal force exerted by the rotation platform, thus, position shifts are determined by the capacitance between carbon nanotubes and the electrode, and the operating frequency of the carbon nanotube oscillator. This measurement system, tracking oscillations of the carbon nanotube oscillator, can be used as the sensor for numerous types of devices, such as motion detectors, accelerometers and acoustic sensors.

• 센서학회지
• /
• 제26권6호
• /
• pp.391-396
• /
• 2017

Human body motion detection is important in several industry sectors, such as entertainment, healthcare, rehabilitation, and so on. In this paper, we first discuss commercial human motion detection technologies (optical markers, MEMS acceleration sensors, infrared imaging, etc.) and then explain recent advances in the development of flexible and stretchable strain sensors for human motion detection. In particular, flexible and stretchable strain sensors that are fabricated using carbon nanotubes, silver nanowires, graphene, and other materials are reviewed.

• 산업기술연구
• /
• 제26권B호
• /
• pp.249-255
• /
• 2006

In this paper, we study the river level/velocimetry measuring system using the ultrasonic sensor to acquire the more precise data from the river circumstance in rainy season. We design the two ultrasonic sensor system to calculate the water level and surface current speed of the river using the dedicated hardware and software. We investigate the validity and effectiveness of the proposed system which applied to the real river environment monitoring system that will be extended to the GIS.

• 한국군사과학기술학회지
• /
• 제5권2호
• /
• pp.159-168
• /
• 2002

In this paper, a study on the design of the transmitter-receiver of fuze sensor for discriminating target position is presented. We propose the algorithm for detecting target distance/direction through investigating the operational concept and principle of fuze sensor. Based on the algorithm, We design transmitter-receiver, calculate various design variables and estimate the performance of that one. The estimated result shows that the required performance of fuze sensor is satisfied. Further research on confirming the performance of proposed algorithm through encounter simulation test with real target and resolving problem will be continued.

• 한국군사과학기술학회지
• /
• 제10권3호
• /
• pp.34-42
• /
• 2007

It is very important for the combat system to process extensive data exactly at short time for the better situation awareness compared with the threats in these days. This paper suggests to add radial velocity on the decision factor of sensor data fusion in the existing algorithm for the accuracy enhancement of the sensor data fusion in the combat system.