• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5427-5433
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• 2012

In this paper a ultrasonic level meter for accurately and simply measuring oil levels of vehicle transmission is developed and its effectiveness is shown by experiments. By using a FPGA, all digital signal processes for the oil level calculation is fulfilled, and the programming on a FPGA project IDE enables very short developing time. And besides, analog circuits including a transmit/receive switch, multi-stage active filters and an envelope detect circuit are designed to process low-level ultrasonic echo signal. Under experiments, the designed level meter has proven to have the accuracy of about within 1[mm] scale.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.36-47
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• 1999

Three-way catalyst converter, cleaning up the exhaust gas contamination of SI engine, has the best efficiency when A/F ratio is near the stoichiometry . The feedback control using oxygen sensors in the exhaust manifold has limits caused by the system delays. So the accurate measurement of air flow rate to an engine is essential to control the fuel injection rate especially on transient condition like the rapid throttle opening and closing. To measure the rapid change of flow rates. the air flow meter for the engine requires quick response, flow reversal detection, and linearity . Tjhe proposed integration type air flow meter (IFM), composed of an ultrasonic flow meter with an integration circuit, has significantly improved the measurement accuracy of air mass inducted through the throttle body. The proposed control method estimated the air mass at the cylinder port using the measured air mass at the throttle . For the fuel dynamic model, the two constant fuel model is introduced . The control parameters from air and fuel dynamics are tuned to minimize the excursion of the air fuel ratio. As a result A/F ratio excursion can be reduced within 5% when throttle rapidly opens and closes at the various engine conditions.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.3
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• pp.141-146
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• 2016

The AMR(automatic meter reading) system has been increasingly and widely used for its efficient and intelligent management, which is a technology that automatically collects consumption data from a water meter or energy metering device. The digital meter instead of the mechanical meter should be used in the system. Up to now, various types of sensor to measure the water flow rate have been used in the digital water meter, for example, reed switch, photo IR approximate sensor, ultrasonic sensor, electromagnetic sensor, etc. In this paper, a new sensing technology, where a variable capacitor and digital circuit were used for sensing the water flow rate, was proposed. The circuit was designed and verified by Pspice simulation. And a PCB board for the circuit was fabricated. After then, a prototype of digital water meter using a variable capacitor to measure the water flow rate was fabricated. The function tests of the fabricated digital water meter were performed, and it was found that the meter worked properly. Since the new technology has much better properties in terms of cost and power consumption compared to conventional technologies, it should be one of the major digital water meter technologies in the future.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.287-294
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• 2005

Flow rate measurement uncertainties of the ultrasonic flow meter are generally influenced by many different factors, such as Reynolds number, flow distortion, turbulence intensity, wall surface roughness, velocity integration method along the acoustic paths, and transducer installation method, etc. Of these influencing factors, one of the most important uncertainties comes from the velocity integration method. In the present study, a optimization weighting factor method for 5-chord, which is given by a function of the chord locations of acoustic paths, is employed to obtain the mean velocity in the flow through a pipe. The power law profile is assumed to model the axi-symmetric pipe flow and its results are compared with the present weighting factor concept. For an asymmetric pipe flow, the Salami flow model is applied to obtain the velocity profiles. These theoretical methods are also compared with the previous Gaussian, Chebyshev, and Tailor methods. The results obtained show that for the fully developed turbulent pipe flows with surface roughness effects, the present weighting factor method is much less sensitive than Chebyshev and Tailor methods, leading to a better reliability in flow rate measurement using the ultrasonic flow meters.

• 전자공학회논문지 IE
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• v.47 no.4
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• pp.1-9
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• 2010

This paper describes a ultrasonic signal processing front-end IC for distance range meter and body detector. The burst shaped ultrasonic signal is generated by a self oscillator and its frequency range is about 40[kHz]-300[kHz]. The generated ultrasonic signal transmit through piezo resonator. The another piezo device transduce from received ultrasonic signal to electrical signals. This front-end IC contained low noise amplifier, band pass filter, busrt detector and time pulse generator and so on. This IC has two type of new idea for improve function and performance, which are self frequency control (SFC) and Variable Gain Control amplifier (VGC) scheme. The dimensions and number of external parts are minimized in order to get a smaller hardware size. This device has been fabricated in a O.6[um] double poly, double metal 40[V] High Voltage CMOS process.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.1
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• pp.138-143
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• 2003

Ultrasonic flowmeters have more advantages than the conventional method using pressure-difference. In these reasons, many advanced nations are already selling the commercial model. In RIST, we have been developed ultrasonic gas flow meter for the localization since a project was been contracted with POSCO in 1997. This paper describes a new ultrasonic gas flowmeter. This ultrasonic gas flowmeter is developed for accurate measurement of gases in a harsh environmental conditions. It is especially suited for measuring LDG. COG, BFG gases produced in iron & steel making process. In this study, we had developed the commercial model about the first tested model and applied a completed system to the POSCO gas line. Its performance has been proven by extensive field tests for several months in POSCO, iron & steel making company.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2313-2321
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• 2014

A concentration meter is widely used at purification plants, sewage treatment plants and waste water treatment plants to sort and transfer high concentration sludge and to control the amount of chemical input. This study has been prepared for improving efficiency of operation on sludge processes and to establish a basic for factory automation by accuracy improvement and problem solution of sludge concentration meter. The concentration meter's accuracy and stability is improved by applying multi-beam sensors and minimum deviation linear average filtering. Furthermore maintenance without cut-off of water in sludge operation is possible by detachable sensors. The performance of multi-beam concentration meter has been variously verified by the pilot plant experiment.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.76-81
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• 2001

Ultrasonic flowmeters have more advantages than the conventional method using pressure-difference. In these reasons, many advanced nations are already selling the commercial model. In RIST, we have been developed ultrasonic gas flow meter for the localization since a project was been contracted with POSCO in 1997. This paper describes a new ultrasonic gas flowmeter. This ultrasonic gas flowmeter is developed for accurate measurement of gases in a harsh environmental conditions. It is especially suited for measuring LDG, COG, BFG gases produced in iron & steel making process. In this study, we had developed the commercial model about the first tested model and applied a completed system to the POSCO gas line. Its performance has already well been proven by extensive field tests for several months in POSCO, iron & steel making company.

• Fashion & Textile Research Journal
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• v.25 no.3
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• pp.386-397
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• 2023

In this study, the efficacy of ultrasonic washing in cotton and wool fabrics was compared and evaluated against conventional washing in terms of cleaning properties and fabric deformation. Factors such as washing temperature, time, liquid ratio, and detergent concentration were kept varied, and the cleaning properties of sebum-soiled fabrics were assessed using different detergents such as alcohol ethoxylate, linear alkylbenzenesulfonate, and IEC 60456 Reference Detergent A^*. In addition, the effects and emulsification power of enzymes and oxygen bleach were examined. To compare the cleaning properties with general washing, a launder-O-meter was used. To investigate fabric deformation during the washing process, the loosening test cloth, shrinkage test cloth, and mechanical strength test cloth were compared between ultrasonic washing machines and household drum washing machines. The results indicate that ultrasonic washing exhibits superior cleaning properties than launder-O-meter when the temperature is low and the washing time is short. Furthermore, there is less deformation and damage during the washing process. It was also observed that the activity of the detergent increases when ultrasonic waves are applied to the washing process. Considering the increasing tendency to pursue convenience and simplicity in clothing management as well as the anticipated commercialization of smart clothing with built-in electric circuits, ultrasonic laundry could serve as a new alternative to existing laundry methods.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.76-76
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• 2002