• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.215-218
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• 2005

In this research, design scheme of fiber Bragg grating(FBG) sensor system for aircraft application is suggested from the results and the know-how from the fon11er researches on structural health monitoring techniques using fiber optic sensors. Design factors to be taken into consideration were derived for both sensor parts including connection and system parts. For the stability of FBG sensor system, design requirements of temperature, vibration, humidity, electromagnetic interference were presented from U. S. military standards. The direction of software programming which increases stability and perfon11ance of the aircraft with the FBG sensor system was also examined.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권10호
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• pp.431-435
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• 2003

It is very difficult and dangerous to measure PD(Partial Discharges) from high voltage equipments in outdoor situation. But that is very important thing for preventing them from more serious accident by defects made by insulating degradation. This paper provides useful method to detect PD signals easily without any dangerous situation. Electric field sensor by the principle of capacitor can detect PD signals without direct connection between sensor and high voltage equipment and has very wide frequency range suitable for noise rejection. Electric field sensor and related circuit for processing PD signal show good performance as a PD sensor when it is applied to simulated high power equipment generating PD pulses.

• 한국해양공학회지
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• 제26권1호
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• pp.27-33
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• 2012

This paper presents the effect of temperature on the impedance-based damage monitoring of steel-bolt connections using wireless impedance sensor nodes. In order to achieve the objective, the following approaches are implemented. First, a temperature-compensated damage monitoring scheme that includes a temperature compensation model and damage detection method is described. The temperature compensation model is designed by analyzing the linear regressions between the temperatures and impedance signatures. The correlation coefficient of the impedance signatures is selected as the damage index to monitor the damage occurrence in the target structures. Second, a wireless impedance sensor node is described for the design of the hardware components and embedded software. Finally, the performance of the temperature-compensated impedance-based damage monitoring scheme is evaluated for detecting a loose bolt in the steel-bolt connections on a lab-scale steel girder under various temperatures.

• Smart Structures and Systems
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• 제9권6호
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• pp.489-504
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• 2012

For the safety of prestressed structures such as cable-stayed bridges and prestressed concrete bridges, it is very important to ensure the prestress force of cable or tendon. The loss of prestress force could significantly reduce load carrying capacity of the structure and even result in structural collapse. The objective of this study is to present a smart PZT-interface for wireless impedance-based prestress-loss monitoring in tendon-anchorage connection. Firstly, a smart PZT-interface is newly designed for sensitively monitoring of electro-mechanical impedance changes in tendon-anchorage subsystem. To analyze the effect of prestress force, an analytical model of tendon-anchorage is described regarding to the relationship between prestress force and structural parameters of the anchorage contact region. Based on the analytical model, an impedance-based method for monitoring of prestress-loss is conducted using the impedance-sensitive PZT-interface. Secondly, wireless impedance sensor node working on Imote2 platforms, which is interacted with the smart PZT-interface, is outlined. Finally, experiment on a lab-scale tendon-anchorage of a prestressed concrete girder is conducted to evaluate the performance of the smart PZT-interface along with the wireless impedance sensor node on prestress-loss detection. Frequency shift and cross correlation deviation of impedance signature are utilized to estimate impedance variation due to prestress-loss.

• 대한의용생체공학회:의공학회지
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• 제30권3호
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• pp.185-190
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• 2009

Biomedical mobile devices for ubiquitous healthcare consist of biomedical sensors and communication terminal. They have two types of configuration. One is the sensor-network type device using wired or wireless communication with intelligent sensors to acquire biomedical data. The other is the sensor embedded type device, where the data can be acquired directly by itself. There are many examples of sensor network type, such as, fall detection sensor, blood glucose sensor, and ECG sensors networked with commercial PDA phone and commercial phone terminal for ubiquitous healthcare. On the other hand, sensor embedded type mounts blood glucose sensor, accelerometer, and etc. on commercial phone. However, to enable true ubiquitous healthcare, motion sensing is essential, because users go around anywhere and their signals should be measured and monitored, when they are affected by the motion. Therefore, in this paper, two biomedical mobile devices with motion monitoring function were addressed. One is sensor-network type with motion monitoring function, which uses Zigbee communication to measure the ECG, PPG and acceleration. The other is sensor-embedded type with motion monitoring function, which also can measure the data and uses the built-in cellular phone network modem for remote connection. These devices are expected to be useful for ubiquitous healthcare in coming aged society in Korea.

• International journal of advanced smart convergence
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• 제5권1호
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• pp.1-7
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• 2016

Recently, introduced a cloud computing technology to the IT industry, smart phones, it has become possible connection between mobility terminal such as a tablet PC. For dissemination and popularization of movable wireless terminal, the same operation have focused on a viable mobile cloud in various terminal. Also, it evolved Wireless Sensor Network(WSN) technology, utilizing a Body Sensor Network(BSN), which research is underway to build large Ubiquitous Sensor Network(USN). BSN is based on large-scale sensor networks, it integrates the state information of the patient's body, it has been the need to build a managed system. Also, by transferring the acquired sensor information to HIS(Hospital Information System), there is a need to frequently monitor the condition of the patient. Therefore, In this paper, possible sensor information exchange between terminals in a mobile cloud environment, by integrating the data obtained by the body sensor HIS and interoperable data DBaaS (DataBase as a Service) it will provide a base of mBodyCloud System. Therefore, to provide an integrated protocol to include the sensor data to a standard HL7(Health Level7) medical information data.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1231-1235
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• 2004

The needs of micro scale thermal detecting technique are increasing in biology and chemical industry. For example, Thermal finger print, Micro PCR(polymer chain reaction), ${\mu}TAS$ and so on. To satisfy these needs, we developed a DTSA(Diode Temperature Sensor Array) for detecting and controlling the temperature on small surface. The DTSA is fabricated by using VLSI technique. It consists of 32 ${\times}$ 32 array of diodes (1,024 diodes) for temperature detection and 8 heaters for temperature control on a 8mm ${\times}$ 8mm surface area. The working principle of temperature detection is that the forward voltage drop across a silicon diode is approximately proportional to the inverse of the absolute temperature of diode. And eight heaters ($1K{\Omega}$) made of poly-silicon are added onto a silicon wafer and controlled individually to maintain a uniform temperature distribution across the DTSA. Flip chip packaging used for easy connection of the DTSA. The circuitry for scanning and controlling DTSA are also developed

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권8호
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• pp.3079-3089
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• 2015

In this paper, a smart constrained application protocol (CoAP)-based gateway with a border router is proposed for home safety services to remotely monitor the trespass, fire, and indoor air quality. The smart CoAP gateway controls a home safety sensor node with a pyroelectric infrared motion sensor, a fire sensor, a humidity and temperature sensor, and a non-dispersive infrared CO2 sensor and gathers sensing data from them. In addition, it can convert physical sensing data into understandable information and perform packet conversion as a border router for seamless connection between a low-power wireless personal area network (6LoWPAN) and the Internet (IPv6). Implementation and laboratory test results verify the feasibility of the smart CoAP gateway which especially can provide about 97.20% data throughput.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1480-1481
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• 2006

It is very difficult and dangerous to measure partial discharge from high voltage equipment in outdoor situation. But that is very important thing for preventing serious accidents from defects which originated in insulating degradation. This paper provides useful method to detect PD signals easily without any dangerous situation. Electric field sensor by the principle of capacitor detect PD signals without direct electrical connection between sensor and high power equipment and has very wide frequency range suitable for noise rejection. Electric field sensor and related circuit for processing PD signal showed good performance as a PD sensor when it is applied to simulated high power equipment generating PD pulse.

• International Journal of Computer Science & Network Security
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• 제22권7호
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• pp.51-56
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• 2022

In the previous years, Wireless Sensor Networks (WSNs) have increased expanding consideration from both the clients and scientists. It is utilized as a part of different fields which incorporate ecological, social insurance, military and other business applications. Sensor hubs are battery fueled so vitality imperatives on hubs are extremely strict. At the point when battery gets released, sensor hub will get detached from remaining system. This outcomes in connection disappointment and information misfortune. In a few applications battery substitution is likewise impractical. Consequently, vitality proficient strategies ought to be outlined which will upgrade lifetime of system and precise information exchange. In this paper, diverse wellsprings of vitality dissemination are recorded trailed by vitality effective systems to improve lifetime of the system.