• Journal of Mechanical Science and Technology
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• v.20 no.4
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• pp.505-512
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• 2006

This paper presents an integrated multifunctional sensor based on MEMS technology, which can be used or embedded in mobile devices for environmental monitoring. An absolute pressure sensor, a temperature sensor and a humidity sensor are integrated in one silicon chip of which the size is $5mm\times5mm$. The pressure sensor uses a bulk-micromachined diaphragm structure with the piezoresistors. For temperature sensing, a silicon temperature sensor based on the spreading-resistance principle is designed and fabricated. The humidity sensor is a capacitive humidity sensor which has the polyimide film and interdigitated capacitance electrodes. The different piezoresistive orientation is used for the pressure and temperature sensor to avoid the interference between sensors. Each sensor shows good sensor characteristics except for the humidity sensor. However, the linearity and hysteresis of the humidity sensor can be improved by selecting the proper polymer materials and structures.

• Journal of Sensor Science and Technology
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• v.23 no.5
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• pp.310-313
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• 2014

We report a way to improve the ability of graphene to operate as a gas sensor by applying single stranded deoxyribonucleic acid (DNA). The sensitivity and recovery of the DNA-graphene sensor depending on the different DNA sequences are analyzed. The different sensor responses to reactive chemical vapors are demonstrated in the time domain. Because of the chemical gating effect of the deposited DNA, the resulting devices show complete and rapid recovery to baseline unlike the bare graphene at room temperature. The application of the pattern recognition technique can increase the potential of DNA-graphene sensors as a chemical vapor classifier.

• Bulletin of the Korean Chemical Society
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• v.28 no.9
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• pp.1455-1456
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• 2007

• Journal of Mechanical Science and Technology
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• v.15 no.10
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• pp.1369-1379
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• 2001

This paper focuses on a development of a sensor system measuring locations of a vehicle to localize a mobile robot while it tracks on the track (location sensor) . Also it focuses on a system configuration identifying the vehicle's orientation and distance from the object while it is stationary at certain station (position sensor) . As for the location sensor it consists of a set of sensors with a combined guiding and counting sensor, and an address-coded sensor to localize the vehicle while moving on the rail. For the position sensor a PSD (Position Sensitive Device) sensor with photo-switches sensor to measure the offset and orientation of the vehicle at each station is introduced. Both sensor systems are integrated with a microprocessor as a data relay to the main computer controlling the vehicle. The location sensor system is developed and its performance for a mobile robot is verified by experiments. The position measuring system is proposed and is robust to the environmental variation. Moreover, the two kinds of sensor systems guarantee a low cost application and high reliability.

• Journal of Information Processing Systems
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• v.1 no.1 s.1
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• pp.49-54
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• 2005

With the recent advances in Micro Electro Mechanical System (MEMS) technology, low cost and low power consumption wireless micro sensor nodes have become available. However, energy-efficient routing is one of the most important key technologies in wireless sensor networks as sensor nodes are highly energy-constrained. Therefore, many researchers have proposed routing protocols for sensor networks, especially cluster-based routing protocols, which have many advantages such as reduced control messages, bandwidth re-usability, and improved power control. Some protocols use information on the locations of sensor nodes to construct clusters efficiently. However, it is rare that all sensor nodes know their positions. In this article, we propose another cluster-based routing protocol for sensor networks. This protocol does not use information concerning the locations of sensor nodes, but uses the remaining energy of sensor networks and the desirable number of cluster heads according to the circumstances of the sensor networks. From performance simulation, we found that the proposed protocol shows better performance than the low-energy adaptive clustering hierarchy (LEACH).

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.840-843
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• 2019

IoT 산업이 발전하면서 기존 토이와 IoT 기술을 결합한 스마트토이가 각광 받고 있다. 스마트토이는 수동적인 방식의 기존토이와는 다르게 토이 간 인터렉션이 가능하며 전자 센서들을 사용하여 토이를 사용하는 어린아이들에 코딩을 활용한 콘텐츠를 제공가능하다. 기존 스마트토이는 처음에는 호기심을 자극하지만, 익숙해지면 흥미가 떨어지는 현상을 보인다. 이에 본 논문에서는 기존 스마트토이가 갖는 재미요소 증가와 다양한 콘텐츠의 개발을 위해서 스마트 토이에 Artificial Intelligence(AI) 기능을 접목한 AI 카메라블록을 사용하여 새로운 콘텐츠를 개발하였다.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.6
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• pp.546-551
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• 2011

Tilt sensor is required to control the attitude of the biped robot when it walks on an uneven terrain. Vision sensor, which is used for recognizing human or detecting obstacles, can be used as a tilt angle sensor by comparing current image and reference image. However, vision sensor alone has a lot of technological limitations to control biped robot such as low sampling frequency and estimation time delay. In order to verify limitations of vision sensor, experimental setup of an inverted pendulum, which represents pitch motion of the walking or running robot, is used and it is proved that only vision sensor cannot control an inverted pendulum mainly because of the time delay. In this paper, to overcome limitations of vision sensor, Kalman filter for the multi-rate sensor fusion algorithm is applied with low-quality gyro sensor. It solves limitations of the vision sensor as well as eliminates drift of gyro sensor. Through the experiment of an inverted pendulum control, it is found that the tilt estimation performance of fusion sensor is greatly improved enough to control the attitude of an inverted pendulum.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.174-176
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• 2006

Sensor network supports data delivery from Physical world to cyber space. Sensors get physical events then wireless network transfers sensor data to service server. We use sensor network technology to light control system for intelligent building. In ubiquitous computing environment. wireless sensor network is basic tool for intelligent service. In this paper, we propose intelligent building light control system based on wireless sensor network. It is implemented using previous light control product, can be adopted to present building light system.

• Journal of Sensor Science and Technology
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• v.16 no.2
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• pp.126-131
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• 2007

In this paper, we fabricated piezoresistive pressure sensor with dry etching technology which used ICP-RIE (inductively coupled plasma reactive ion etching) and etching delay technology which used SOI (silicon-on-insulator). Structure of the fabricated pressure sensor shows a square diaphragm connected to a frame which was vertically fabricated by dry etching process and a single-element four-terminal gauge arranged at diaphragm edge. Sensitivity of the fabricated sensor was about 3.5 mV/V kPa at 1 kPa full-scale. Measurable resolution of the sensor was not exceeding 20 Pa. The nonlinearity of the fabricated pressure sensor was less than 0.5 %F.S.O. at 1 kPa full-scale.

• Journal of Sensor Science and Technology
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• v.25 no.3
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• pp.208-212
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• 2016

In this work, a loop sensor for Arc-Flash detections has been developed in order to trip a circuit breaker within 2.5 ms after an Arc-Flash event. For an efficient capturing of the flash light, plastic optical fibers, where light attenuations are larger than those in silica-based ones, with different diameters and surface conditions were utilized. The performance was comparatively analyzed with those of a point sensor and a commercialized product. The point sensor module was designed for hemisphere-like capturings of Arc-Flashes larger than 3 kA at 2 meters from the sensor. On the other hand, the loop sensor allowed 360-degree-detections around the fiber axis and the measurement range was dependent on the length of the fiber connected to the sensor module. The trip-level-dependent brightness measurement results showed that the fabricated point sensor and loop sensor satisfied a brightness condition, 10~40 klux, and the responses of the system to Arc-Flashes were completed within 2.5 ms.