• International Journal of Contents
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• v.3 no.4
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• pp.1-7
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• 2007

There has been increased interest in wireless sensors in the last few years. This paper provides insight into the properties that make these sensors so attractive, specifically considering their efficiency, data reliability, and the ability to verify the data generated. Some advantages a wireless network presents over traditional information sensing are discussed as well. The paper considers how the environmental field can benefit from using these networks. Some of the possible challenges this industry will face in adopting this new method of data sampling and collection are also considered. A project we conducted raised concern over measures needed for the integrity of the communication system to be maintained, thus ensuring the integrity of the data being collected. From results of an experimental project conducted in York University, the reliability and usefulness of a sensor network is discussed.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.11-13
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• 2005

The Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) concluded that many collective observations gave a aspect of a global warming and other changes in the climate system. Future earth observation using satellite data should monitor global climate change, and should contribute to social benefits. Especially, human activities has given the big impacts to earth environment This is a very complex affair, and nature itself also impacts the clouds, namely the seasonal variations. JAXA (former NASDA) has the plan of the Global Change Observation Mission (GCOM) for monitoring of global environmental change. SGLI (Second Generation GLI) onboard GCOM-C (Climate) satellite, which is one of this mission, is an optical sensor from Near-UV to TIR. This sensor is the GLI follow-on sensor, which has the various new characteristics. Polarized/multi-directional channels and 250m resolution channels are the unique characteristics on this sensor. This sensor can be contributed to clarification of coastal change in sea surface. This paper shows the introduction of the unique aspects and characteristics of the next generation satellite sensor, SGLIIGCOM-C, and shows the preliminary research for this sensor.

• Smart Structures and Systems
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• v.15 no.6
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• pp.1543-1567
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• 2015

In this study, a wireless crack sensor is developed for monitoring cracks propagating in two dimensions. This sensor is developed by incorporating a laser-based optical navigation sensor board (ADNS-9500) into a smart wireless platform (Imote2). To measure crack propagation, the Imote2 sends a signal to the ADNS-9500 to collect a sequence of images reflected from the concrete surface. These acquired images can be processed in the ADNS-9500 directly (the navigation mode) or sent to Imote2 for processing (the frame capture mode). The computed crack displacement can then be transmitted wirelessly to a base station. The design and the construction of this sensor are reported herein followed by some calibration tests on one prototype sensor. Test results show that the sensor can provide sub-millimeter accuracy under sinusoidal and step movement. Also, the two modes of operation offer complementary performance as the navigation mode is more accurate in tracking large amplitude and fast crack movement while the frame capture mode is more accurate for small and slow crack movement. These results illustrate the feasibility of developing such a crack sensor as well as point out directions of further research before its actual implementation.

• Journal of Sensor Science and Technology
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• v.25 no.6
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• pp.423-430
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• 2016

This study used a single metal oxide semiconductor (MOS) sensor to classify the major odorous gases hydrogen sulfide ($H_2S$), ammonia ($NH_3$) and toluene ($C_6H_5CH_3$). In order to classify these odorous substances, the voltage on the MOS sensor heater was gradually reduced in 0.5 V steps 5.0 V to examine the changes to the response by the cooling effect on the sensor as the voltage decreased. The hydrogen sulfide gas showed the highest sensitivity compared to odorless air under approximately 2.5 V and the ammonia and toluene gases showed the highest sensitivity under approximately 5.0 V. In other words, the hydrogen sulfide gas reacted better in the low temperature range of the MOS sensor, and the ammonia and toluene gases reacted better in the high-temperature range. In order to analyze the response characteristics of the MOS sensor by temperature in a pattern, a two-dimensional (2D) x-y pattern analysis was introduced to clearly classify the hydrogen sulfide, ammonia, and toluene gases. The hydrogen sulfide gas was identified by a straight line with a slope of 1.73, whereas the ammonia gas had a slope of 0.05 and the toluene gas had a slope of 0.52. Therefore, the 2D x-y pattern analysis is suggested as a new way to classify these odorous substances.

• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.946-949
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• 2007

A wireless sensor network (WSN) is a wireless network consisting of spatially distributed autonomous devices using sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion at different locations. Environmental monitoring represent a class of sensor network applications with enormous potential benefits for scientific communities and society. In this paper we design and implement a novel platform for sensor networks to be used for monitoring of temperature, humidity, and light sensors.

• Environmental Analysis Health and Toxicology
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• v.19 no.1
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• pp.41-47
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• 2004

Air quality monitoring is a primary activity for industrial and social environment. The government push for pollutants that must be monitored. Especially, the VOCs (Volatile Organic Compounds), which are very harmful for human and environment, should be controlled under the government policy. We have been developed a VOCs measurement system which recognize various kinds and quantities of VOCs, such as benzene, toluene, and xylene (BTX). Especially, we designed sensor array with various kinds of gas sensor and ANN (Artificial Neural Network) algorithm. The measured values for BTX have errors of-4ppm.

• Journal of Sensor Science and Technology
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• v.20 no.4
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• pp.279-285
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• 2011

This study was carried out to apply chemical gas sensors for the identification of bad breath which is one of the important sensitive problem for the humans' daily life. Seven sensors, including five semiconductor sensors and two electrochemical sensors, were tested for the three panels three times in several conditions. The results showed that the reproducibility of sensors were generally good, and electrochemical sensors showed better reproducibility while semiconductor sensors showed better sensitivity. No rinsing before measurement showed relatively better results in terms of both sensitivity and reproducibility. Semiconductor gas sensors for hydrogen sulfide shows the highest sensitivity, and it was recommended to use the odor-free bag for the measurement of bad breath.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6A
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• pp.481-487
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• 2005

In order to increase the autonomous navigation capability of a mobile robot, it is very crucial to develop a method for recognizing a priori known environmental characteristics. This paper proposes an ultrasonic sensor based real-time method for recognizing a priori known indoor environmental characteristics like a wall and corner. The ultrasonic sensor consists of an ultrasonic transmitter and two ultrasonic receivers placed symmetrically about the transmitter. Unlike previous methods the information obtained from the sensor is processed in real-time by extended Kalman filter to be able to correct the position and orientation of robot with respect to known environmental characteristics.

• Structural Engineering and Mechanics
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• v.65 no.2
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• pp.155-162
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• 2018

A smart glass fiber reinforced polymer (SMFRP) reinforcing bar with a fiber Bragg grating (FBG) sensor was fabricated using a pultrusion technique, while ribs were formed to improve bonding between concrete and SMFRP. Then, strain of SMFRP bars were measured for a uniaxial tension test of an SMFRP bar, and a four-point bending test of concrete beams reinforced with SMFRP bars. The results of a uniaxial tension test illustrate that the strain obtained from an FBG sensor agrees well with that obtained from electrical resistance strain gauge (ERSG). Additionally, concrete beams reinforced with SMFRP bars were fabricated, and actual flexural test were performed while the strain of with an FBG sensor was compared with that of ERSG. The experimental results demonstrate that SMFRP bars can be used as reinforcement of concrete member while providing deformation information. Furthermore, SMFRP bars may provide stronger durability and smart monitoring to reinforced concrete members under corrosive environments during a service life.