• Journal of Institute of Control, Robotics and Systems
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• v.13 no.6
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• pp.568-573
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• 2007

Environmental information (temperature, humidity, vibration, $CO_2$, gas leakage, etc.) of building is an essential item to manage and monitor a building. For intelligent building, it is necessary to get temperature and illumination information to save energy and crack information to prevent structural problems. Moreover, temperature and gas leakage information to alarm a tire precaution, or humidity information to maintain comfortable environment. However, there have not been many researches on systems for gathering environmental information and building maintenance due to high costs. In this paper, wireless sensor network technology is applied to collecting building environmental information. Wireless sensor network is one of the latest issues and has low-power consumption, low-cost, self-configuration features.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.2
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• pp.57-65
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• 2008

Wireless sensor networks achieve environment monitoring and controlling through use of small devices of low cost and low power. Such network is comprised of several sensor nodes, each having a microprocessor, sensor, actuator and wired/wireless transceiver inside a small device. In this paper, we employ the sensor networks in order to design and implement a real-time vehicle safety system. Such system can inform the safe velocity in a specific weather condition to drivers in advance through analyzing the weather data collected from sensor networks. As a result, the drivers can prevent effectively accidents by controlling their car speed.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.214-214
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• 2000

This paper deals with the non contact optical sensor to measure the shape of transparent plates such as glass panel of LCD(Liquid Crystal Display). The conventional methods to obtain the shape or thickness of a transparent plates are contact type sensor such as LVOT(Linear Variable Differential Transformer). Due to the contact between the tip of the sensor and the surface of objects, the tip is abraded. In addition, the high temperature glass casting makes the size of sensor body changed. These reasons makes the sensor degraded. In this paper, to overcome these problem, we proposed a low cost noncontact optical sensor this is composed of the Hologram laser unit of a CD-Pickup and a plastic lens. To evaluate the performance of the proposed optical sensor, a series of experiments were performed for various measurement condition. Based upon observation of the experimental result, the developed sensor shows good result for measuring the shape of transparent plates.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1310-1313
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• 1997

Application of eddy current sensing principle for the non-contact estimation of very low concentration of electrolytic solution is presented in this paper. for this application, a new, simple, low-cost, low-power structure for the eddy current sensor is proposed. By measuring the eddy current produced in the conducting electrolytic solution, the concentration is estimated. Therefore, the unknown concentration can be estimated comparing with the database which is prepared as the relation between the change in inductance and various concentrations of electrolytic solution. The concentration, as low as l ppm of the solutioin can be detected by this sensor. It was tested on various low concentration solutions of NaCl. It shows distinct response for various concentrations.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.4
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• pp.9-17
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• 2017

In these days, MEMS (micro-electro-mechanical system) devices become the crucial sensor components in mobile devices, automobiles and several electronic consumer products. For MEMS devices, the packaging determines the performance, reliability, long-term stability and the total cost of the MEMS devices. Therefore, the packaging technology becomes a key issue for successful commercialization of MEMS devices. As the IoT and wearable devices are emerged as a future technology, the importance of the MEMS sensor keeps increasing. However, MEMS devices should meet several requirements such as ultra-miniaturization, low-power, low-cost as well as high performances and reliability. To meet those requirements, several innovative technologies are under development such as integration of MEMS and IC chip, TSV(through-silicon-via) technology and CMOS compatible MEMS fabrication. It is clear that MEMS packaging will be key technology in future MEMS. In this paper, we reviewed the recent development trends of the MEMS packaging. In particular, we discussed and reviewed the recent technology trends of the MEMS bonding technology, such as low temperature bonding, eutectic bonding and thermo-compression bonding.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.290-293
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• 1988

This paper shows the development of robot sensor system using optical fiber. When the object recognition is implemented in the existing robot system, the image processing method using CCTV-Camera has been most widely used. But when it is necessary to recognize and classify only simple elements in industrial field, the real time processing using this method requires relatively high cost. The purpose of this paper is to represent the fundamental study on the development of optical-fiber sensor system, which may be used to recognize and classify elements with low cost and real-time.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.385-387
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• 1999

Brushless DC Motors are widely used because of their high power ratio and easy control. But the brushless DC Motors need rotor Position- and speed- sensor such as encoder, resolver and hall sensor. The position sensor has present several disadvantages from the standpoint of drive cost, machine size and reliability. Hall sensors are used generally because of low cost but their operating temperature is limited up to $75^{\circ}C$ because of sensitivity of temperature. Now a day many research projects are on the development of sensorless brushless DC motors to correct these disadvantages. In this paper, characteristics such as starting, change of speed and load of a sensorless brushless DC motor are investigated.

• Smart Structures and Systems
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• v.18 no.5
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• pp.885-909
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• 2016

Advances in low-cost wireless sensing have made instrumentation of large civil infrastructure systems with dense arrays of wireless sensors possible. A critical issue with regard to effective use of the information harvested from these sensors is synchronized sensing. Although a number of synchronization methods have been developed, most provide only clock synchronization. Synchronized sensing requires not only clock synchronization among wireless nodes, but also synchronization of the data. Existing synchronization protocols are generally limited to networks of modest size in which all sensor nodes are within a limited distance from a central base station. The scale of civil infrastructure is often too large to be covered by a single wireless sensor network. Multiple independent networks have been installed, and post-facto synchronization schemes have been developed and applied with some success. In this paper, we present a new approach to achieving synchronized sensing among multiple networks using the Pulse-Per-Second signals from low-cost GPS receivers. The method is implemented and verified on the Imote2 sensor platform using TinyOS to achieve $50{\mu}s$ synchronization accuracy of the measured data for multiple networks. These results demonstrate that the proposed approach is highly-scalable, realizing precise synchronized sensing that is necessary for effective structural health monitoring.

• Smart Structures and Systems
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• v.4 no.3
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• pp.305-318
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• 2008

The development of a digital signal processor based prototype is described in relation to continuing efforts for realizing a fully self-contained active sensor system utilizing impedance-based structural health monitoring. The impedance method utilizes a piezoelectric material bonded to the structure under observation to act as both an actuator and sensor. By monitoring the electrical impedance of the piezoelectric material, insights into the health of the structured can be inferred. The active sensing system detailed in this paper interrogates a structure utilizing a self-sensing actuator and a low cost impedance method. Here, all the data processing, storage, and analysis is performed at the sensor location. A wireless transmitter is used to communicate the current status of the structure. With this new low cost, field deployable impedance analyzer, reliance on traditional expensive, bulky, and power consuming impedance analyzers is no longer necessary. A complete power analysis of the prototype is performed to determine the validity of power harvesting being utilized for self-containment of the hardware. Experimental validation of the prototype on a representative structure is also performed and compared to traditional methods of damage detection.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.360-365
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• 2010

In this paper, we present a distributed algorithm for detecting dynamic event regions in wireless sensor network with the consideration on energy saving. Our model is that the sensing field is monitored by a large number of randomly distributed sensors with low-power battery and limited functionality, and that the event region is dynamic with motion or changing the shape. At any time that the event happens, we need some sensors awake to detect it and to wake up its k-hop neighbors to detect further events. Scheduling for the network to save the total power-cost or to maximize the monitoring time has been studied extensively. Our scheme is that some predetermined sensors, called critical sensors are awake all the time and when the event is detected by a critical sensor the sensor broadcasts to the neighbors to check their sensing area. Then the neighbors check their area and decide whether they wake up or remain in sleeping mode with certain criteria. Our algorithm uses only 2 bit of information in communication between sensors, thus the total communication cost is low, and the speed of detecting all event region is high. We adapt two kinds of measure for the wake-up decision. With suitable threshold values, our algorithm can be applied for many applications and for the trade-off between energy saving and the efficiency of event detection.