• Proceedings of the KSME Conference
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• 2001.11b
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• pp.764-769
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• 2001

Recently, according to increase in the requirement of electric power, a thermoelectric power plant equipped with pulverized coal combustion system is highly valued, because coal has abundant deposits and a low price compared with others. For efficient use of coal fuel, most of plant makers are studying to improve combustion performance and flame stability, and reduce pollutant emission. One of these studies is how to control the profile of particle injection and velocity dependant on coal nozzle. Basically, a mixed flow of gas and particle in coal nozzle is required to have appropriate injection and concentration distribution at exit to achieve flame stability and low pollutant, but it is very difficult to obtain that without help of a coal separating device within nozzle. In this study, each distribution of air and coal flow rate is measured for the coal nozzle with coal separator developed by us. The coal concentration at exit is various according to inlet swirl values and positions of coal separator. Also pressure drop is measured for various operating conditions of this nozzle. From these results, we can find the separation characteristic of new developed coal separator, and select proper operation range of coal nozzle. When this coal nozzle is applied to actual plant, these investigations will be very useful to confirm the shape of coal separator to have efficient particle injection.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.12
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• pp.990-995
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• 2012

A piezoelectric ultrasonic bone surgical instrument, usually used to remove the tartar out of teeth or to cut the dentine of the tooth, is a recently popular instrument for dental treatment due to its several merits such as small size, low-electric power and precision control of surgical operation. It has typically two parts of a tip and vibration system which is also composed of head, piezoelectric elements and tail-mass. In order to improve the performance of the instrument, it is important to standardize the size of the vibration system without tip for high performance. In this study, a Finite Element Analysis (FEA) was utilized to optimize the structure of ultrasonic instrument in vibration system. Consequently, this study revealed that influence of several tips on property were minimized and it showed good property at the frequency range of 22~32 kHz.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.2
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• pp.134-144
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• 2007

In this study, a smart sensor unit is developed by using the smart sensor technology that is being rapidly developed in recent years for structural health monitoring system, and its performance is evaluated through various experiments, and also, damage detection experiment is performed on a model structure. This paper as the first half of this study contains the development and performance evaluation of the smart sensor. In the latter half of this study, structure damage detection experiment is performed for the application of verified smart sensor unit into structural health monitoring, and it is compared with a wire measurement system. The smart sensor is developed by using high-power wireless modem, MEMS Sensor and AVR microcontroller, and an embedded program is also developed for the control and operation of the sensor unit. To verify the performance of the smart sensor, many experiments are performed for sensitivity and resolution analysis tests, data acquisition by using cantilever beam and shaker, and on-site application using actual bridge. As a result, the smart sensor proves to be satisfactory in its performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.5
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• pp.510-518
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• 2010

In this paper, the designed and implemented results of CFL linearization chip which can be used in mobile radio and TRS terminal of UHF band(380~910 MHz), using $0.6\;{\mu}m$ BiCMOS process based on Si, are shown. As gain control circuits for modifying transmit power are inserted not only in feedback path but also in forward path, the stability of CFL is maintained. And, DC-offset correction function of S/H structure, which is suitable for walkie-talkie PTT operation and is easily implemented, is realized. The performance test results of transmitter show that the regulation of FCC emission mask at PEP 3 W(34.8 dBm) is satisfied when the CQPSK modulated signal is fed and more than 30 dBc improvement of 3rd order IMD is achieved when two-tone signal is inputted.

• Journal of Korea Society of Industrial Information Systems
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• v.8 no.4
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• pp.1-7
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• 2003

This study is concerned with the operational methods of Quality Management employed by the small and medium-sized companies in Gang won-do to improve their power of competition. This study is particular, studied the consortium-participating companies on their Plans of Quality Management as to how they carry them out in order to advance to the first-class business enterprises. The results of this study showed that the of shortage manpower and funds that the local small and mediumsized companies commonly face played a significant role as major obstacles in implementing their Quality Management programs. The study results also suggest that it is necessary to promote some periodic manpower train- ing programs in cooperation with local universities, to utilize professors and experts to build management strategies that can bring and secure the power of competition, and to construct a system of educational-industrial cooperation, as ways leading these companies to the 21s1 century's type of business enterprise.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.7
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• pp.1335-1341
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• 2016

For the safety of train operation, monitoring & supervisory systems for train, signal, power, communication and facilities is operating independently in another place, so, its sensors are interdependently connected from each other to transfer gathering datas of sensing to control center. A Goal of Real-time railway safety supervision system is to improve the safety oversight efficiency and to prevent accidents by means of hazard prediction based on big data by integrating all of safety sensing data in wayside of railway, and the System is requested acquisition of all of sensing data of safety. So, we need special method of protocol converting for the purpose of integrating all of detecting data concerning safety without any changing application. In this paper we investigate the existing converting method in communication field, and propose a new progress to converting protocol adding function of transfer using XML file, and implemented this algorithm, and tested with example packets, finally.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.6
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• pp.359-366
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• 2018

Social infrastructure facilities that have been under construction since the country's high-growth period are undergoing rapid aging, and safety assessments of large structures such as bridge tunnels, which can be directly linked to large-scale casualties in the event of an accident, are necessary. Wireless smart sensor networks that improve SHM(Structural Health Monitoring) based on existing wire sensors are difficult to construct economical and efficient system due to short signal reach. The LPWAN, Low Power Wide Area Network, is becoming popular with the Internet of Things and it is possible to construct economical and efficient SHM by applying it to structural health monitoring. This study examines the applicability of LoRa LPWAN to structural health monitoring and proposes a channel usage pre-planning based LoRa network operation method that can efficiently utilize bandwidth while resolving conflicts between channels caused by using license - exempt communication band.

• Fire Science and Engineering
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• v.23 no.5
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• pp.138-142
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• 2009

The system of The Volunteer Fire Brigade is the Civil autonomic one which was set up from The Chosun Dynasty and has been active. Having suffered from several dificulties from Japanese control in the Chosun Dynasty, The Volunteer Fire Brigade was established by the enactment 1958 Fire Law and we have had it up to this time. The Volunteer Fire brigade played an important role in the period of the past Fire fighting personnel and equipment which we did not have. It has carried out the assistance of the Fire extinction, the early extinction of a fire in the rural region, the extinction of the forest fire, and lots of social volunteering actions etc. but, today's Fire fighting system has made the surprising developments, such as the improvement of national economic power, the increase of knowledge about the safety of the people, the openness of The Fire Fighting Department of Korea. I will try to check out the role of The Volunteer Fire Brigade which filled up the lacking part the fire fighting in the past and make the measures which can activate in these days, looking for the new field of the movement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.615-616
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• 2017

Recently, research are being conducted to provide an automated environment utilizing various sensors in a place where management is use. However, in an existing automation system environment because the measured sensor data is processed in a batch in the server, than the currently action task there arises a problem that a conflict occurs between task when a task that should operate preferentially occurs. In this paper, we propose a system that provides automation using Sensor Data Identification Algorithm to solve these problems. The algorithm distinguishes between real-time and non-real-time tasks and automatically control tasks what happens after priority is applied. Through this, it is expected that it can reduce manager intervention and reduce unnecessary work operation and power consumption and construct an efficient automation environment.

• Journal of Biosystems Engineering
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• v.12 no.2
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• pp.28-37
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• 1987

Operation of rice whiteners has been depending on operator's experience only and very limitted data are available for operational criteria of rice whiteners in Korea. With developments of new rice varieties and with a tendency of automation of machine operations for precision control, operational criteria depending on physical characteristics of rice grains arc required for an improvement of milled rice recovery and the performance of rice whitening systems. An experimental study was conducted to identify operational criteria of a rice whitening system consisted with an abrasive-aerated whitener developed newly and a frictional-aerated whitener being used commercially. Further, comparisons were made between the performance of the rice whitening system adopted for this study and a commercial system used in small scale milling plants. Results of this study are summarized as follows: 1. Total number of passes necessary for the final white rice in the combined whitening system depended exclusively on the counter pressure level of the frictional whitener successive to the abrasive whitener. 2. The counter pressure required for whitening Japonica type rice variety (Akibare) was higher by about 1.6 times than that for Japonica type (Pung-san), when other conditions were kept at the same. 3. Radial pressure in the whitening chamber of the frictional whitener should be maintained between 1.5 to $2.1kg/cm^2$ for the completion of whitening within 5 to 3 passes regardless of rice varieties. Hence, it was found that the radial pressure in the whitening chamber could be used as an operational criteria to control the counter pressure level. 4. The following regression equation was found between radial pressure($R_p$) in whitening chamber and electric power consumption of the whitening system: $$EPC=-0.545\;R^2_p+1.277\;R_p+0.874[KWH/100kg]$$ 5. The following multiple regression equation was found among radial pressure ($R_p$), counter pressure ($C_p$), and bioyield point ($B_i$), length (L) and width (W) of brown rice. $$R_p/(B_i/W^2)=0.547\{C_p/(B_i/W^2)\}^{0.365}(L/W)^{0.120}(R^2=0.9897)$$ 6. The milled rice recovery and machine efficiency (kg/KWH) from the combined whitening system were higher by about 2.0% point and by 15 to 27% point than those from the conventional system, respectively.