• Journal of Institute of Control, Robotics and Systems
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• v.14 no.3
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• pp.248-253
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• 2008

This paper presents a sensing system for smart home which can detect an location transition events such as entrance/exit of a member and identify the user in a group at the same time. The proposed system is compose of two sub-systems; a wireless sensor network system and a database server system. The wireless sensing system is designed as a star network where each of sensing modules with ultrasonic sensors and a Bluetooth RF module connect to a central receiver called Bluetooth access point. We propose a method to discriminate a user by measuring the height of the user. The differences in the height of users is a key feature for discrimination. At the same time, the each sensing module can recognize whether the user goes into or out a room by using two ultrasonic sensors. The server subsystem is a sort of data logging system which read the detected event from the access point and then write it into a database system. The database system could provide the location transition information to wide range of context-aware applications for smart home easily and conveniently. We evaluate the developed method with experiments for three subjects in a family with the installation of the developed system into a real house.

• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1463-1471
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• 2017

In order to monitor the pipe thinning caused by flow-accelerated corrosion (FAC) that occurs in coolant piping systems, a shear horizontal ultrasonic pitch-catch waveguide technique was developed for accurate pipe wall thickness monitoring. A clamping device for dry coupling contact between the end of the waveguide and pipe surface was designed and fabricated. A computer program for multi-channel on-line monitoring of the pipe thickness at high temperature was also developed. Both a four-channel buffer rod pulse-echo type and a shear horizontal ultrasonic waveguide type for high-temperature thickness monitoring system were successfully installed to the test section of the FAC proof test facility. The overall measurement error can be estimated as ${\pm}10{\mu}m$ during a cycle from room temperature to $200^{\circ}C$.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.102-108
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• 2016

A dental ultrasonic surgical instrument, commercially known as a scaler, is a high-value-added advanced technology that is used for tartar removal, implant operations, and gum and jaw bone surgery. In this study, the piezoelectric phenomenon for making linear motion associated with input electrical signals was studied, and the behavior of the ultrasonic vibrator was investigated by using the commercially available finite element program ANSYS(R) for the purpose of designing dental surgery tools. Modal analysis was carried out, and the optimal frequency range was calculated from the analyzed results. The ultrasonic vibrator was then redesigned based on the calculated optimal frequency range. The performance of the system was tested, and consequently, the proposed methodology was proven useful in vibrator design.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.167-172
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• 2002

Recent years, optical components'are widely used in optical communication industry for high speed and mass storage data processing. Micro grooving of planar lightwave circuit and glass, those are widely used in optical component, are realized by polycrystalline diamond tool with ultrasonic vibration. To know the characteristics of brittle materials cutting, ultrasonic vibration cutting tool and machining system are built for the experiment. Grooving on planar lightwave circuit and glass experiments are performed and their shape are measured by photograph with microscope. It reveals that better groove shape with low chipping of planar lightwave circuit and glass are obtained by micro grooving machining with ultrasonic vibration. These experiments are considered as a possibility to the micro grooving of optical communication components.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.12
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• pp.94-100
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• 2000

This paper presents a methodology for In-Process monitoring of tool wear by using ultrasonic sensor in turning operation. An integrated single ultrasonic transducer operation at a frequency of 10MHz is placed in contact with the insert tip. The change in amount of the reflected energy from the nose and flank of the tool can be related to the level of tool wear and the mechanical integrity of the tool. As the results, the tool wear monitoring system based on the ultrasonic pulse-echo method was proposed, it is useful to determine a tool life and tool change time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.168-171
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• 2000

Underwater acoustic communications have made considerable advances in the past decade. The purpose of this paper is to achieve the underwater communication by ultrasonic sensors and to investigate conditions of good underwater acoustic communicators. As a result of this experiments, the ultrasonic sensors, MA40E7R/S, made by Nicera can be used as ultrasonic transducers for underwater communication using AM(Amplitude Modulation) signal and Transmission Loss is 17.328[dB] at 65[cm]. To make a good underwater communicator, proper diameter of disk PZT transduers is the one of most important factors, because radiation of acoustic wave depends on proper diameter of transduers and the transmission loss strongly depends on the spreading loss.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.3
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• pp.227-233
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• 2011

The ultrasonic guided wave phased array using magnetostrictive patch transducers is proposed. The magnetostrictive transducer has received much attention because it is cost-effective and capable to generate ultrasonic waves with a simple configuration. However, it has not been used for ultrasonic guided wave phased array applications until now. In this paper, we propose a magnetostrictive transducer based phased array system consisting of a multi-channel function generator, power amplifiers and Lamb wave magnetostrictive transducers. To check the performance of the ultrasonic guided wave phased array, several Lamb wave focusing experiments were carried out in an aluminum plate. The results demonstrated the capability of the developed array to focus the Lamb waves at specific target points.

• Textile Coloration and Finishing
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• v.11 no.5
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• pp.1-6
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• 1999

This study was carried out to investigate the effect of a scouring machine including an ultrasonic system on desizing and scouring polyester fabrics. The ultrasonic frequency of the improved machine showed up at 28.882 kHz. Frequency amplitude increased with the current and the bath temperature, and then showed a constant level. Scouring effect of the ultrasonic machine was better than that of the conventional scouring machine using the mechanical stirring. The ultrasonic machine showed the optimum scouring effect at $50^\circ{C}$ of bath temperature and 10 min. of operation time, as compared to the conventional machine that required operating conditions of high temperature at $90^\circ{C}$, stirring speed at 40 rpm, and stirring time for 15 min..

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.309-316
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• 2017

In shuttle vans designed to transport children, the recognition of a child's approach and departure is very important. Ultrasonic sensors are generally used for a short distance around a vehicle. Although ultrasonic sensors are cheaper than other ADAS sensors, the number of sensors installed in a van should be optimized. In order to recognize the presence of a child around a shuttle van, this paper proposes the placement of ultrasonic sensors in the van. Considering the turning radius of the van and the distance from each sensor to a child, collision risk is classified as 'safe', 'warning', and 'danger'. The sensor placement and the recognition algorithm are verified in a virtual driving environment.

• Electrical & Electronic Materials
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• v.9 no.8
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• pp.825-830
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• 1996

In this study, Characteristics of Ultrasonic Transducer fabricated with porous piezoelectric resonator, 3-D underwater object restoration using the self made ultrasonic transducer and modified SCL(Simple Competitive Learning) neural network are investigated. The self-made transducer was satisfied the required condition of ultrasonic transducer in water, and the modified SCL neural network using the acquired object data 16*16 low resolution image was used for object restoration of $32{\times}32$ high resolution image. The experimental results have shown that the ultrasonic transducer fabricated with porous piezoelectric resonator could be applied for SONAR system.