• Journal of Power Electronics
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• v.4 no.2
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• pp.112-116
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• 2004

The pulsed power systems have been widely used many other countries and their new applications have been developed by many researchers, such as E/P(Electrostatic Precipitator) to remove the industrial dust, DeNOx/DeSOx power systems, ozone generators and power sources of the laser beam, etc. In this paper, we studied the cascading technique as a new technology consisted of two pulse transformers and obtained their experimental data and results. To obtain the high pulsed voltage adopted cascading technique, we designed our compact pulse generator and tested by adjusting the value of the load resistors to obtain high pulsed voltage with steep rising time and duration time. We explained their experimental results that obtained by adopting cascading technique. Also, we compared theoretical value with measured value obtained by using the cascading method.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.3
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• pp.177-185
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• 2000

In this study, the characteristics of various electricity and high resistivity ash collection were measured at superimposed nanosecond pulse energization. The pulse was generated through the hydrogen thyratron. Superimposed pulse was nanosecond duration pulse that had fast pulse rising time 100[ns], short pulse width 500∼850[ns] and pulse fall time 400∼750[ns]. The results of this study are summarized as followings; Frist, compared with the DC ESP(electrostatic precipitator), superimposed pulse ESP could induce higher peak voltage, and had the about 30[%] reduction of ESP collection area and 50∼80[%] reduction of power consumption. showing the same efficiency. Second, enhancement factor H had 1.9∼3.6 with the increase of migration velocity.

• Journal of the Korean Society for Nondestructive Testing
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• v.12 no.4
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• pp.9-17
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• 1993

Three types of piezoelectric sensors to detect acoustic emission signals were developed and characterized. Epicentral displacement and velocity of a plate to have infinite boundary were calculated by convolution between a Green's function and a simulated source time function to show parabolic rising characteristic. The sensor calibration system set up was composed of a steel plate, a glass capillary, an indentor and a load cell indicator The transient elastic signals were detected by the sensors. The results were compared with the theoretical results and Fast Fourier Transformed. As the results, the sensor fabricated using a disk shape of a piezoelectric PZT element showed resonant characteristics. The sensors fabricated using a conical shape PZT element and a PVDF polymer film showed the wide band characteristics for particle displacement and velocity, respectively. The calculated results showed good agreements with the transient responses in the cases of the wide band sensors and it was confirmed that the simulated source time function had been properly assumed.

• Journal of the Korean Society of Safety
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• v.30 no.3
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• pp.45-51
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• 2015

This study was full-scale combustion test for flame growth characteristics and temperature characteristics analysis to predict the risk of household Items fire when fire occurs. Experimental results, Refrigerator flames were the highest measured in 15 min time, and Washing machine is between 20 ~ 30 min, Drawer is 5 min, Sofa was enabled up to the size of the flame 15 min. In addition, the maximum combustion temperature was found from the time 20 min ~ 25 min, Sofa is temperature was elevated up to $1190^{\circ}C$, Refrigerator is $1,162^{\circ}C$, Drawer is $822^{\circ}C$, Washing machine appeared to be rising up to $670^{\circ}C$. Therefore, in the case of the maximum temperature of combustion Sofa it showed relatively high.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.11-15
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• 2005

This paper presents a method to determine the characteristic polynomial of a closed loop all-pole system in order to obtain desired transient response in terms of the overshoot and speed (rising/settling time). The method adjusts the overshoot by doing some changes in the characteristic ratios of the Bessel-Thompson filter. The closed loop speediness is then tuned by suitable choice of the generalized time constant. Simulation results are presented to evaluate the achievements and make comparison with those of a similar method.

• International journal of advanced smart convergence
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• v.1 no.2
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• pp.26-29
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• 2012

Recently, to efficiently support the real-time requirements of RTLS( Real Time Location System) services, interest in the main memory DBMS is rising. In the main memory DBMS, because all data can be lost when the system failure happens, the recovery method is very important for the stability of the database. Especially, disk I/O in executing the log and the checkpoint becomes the bottleneck of letting down the total system performance. Therefore, it is urgently necessary to research about the recovery method to reduce disk I/O in the main memory DBMS. Therefore, In this paper, we analyzed existing log techniques and check point techniques and existing main memory DBMSs' recovery techniques for recovery techniques research for main memory DBMS.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.79-82
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• 1999

The right half plane (RHP) zeros may cause severe problems, such as undershoots, oscillations and time delay in the transient response of the systems. In this paper, we formulate a linear quadratic type problem to deal with the effects of the RHP zeros in the nonminimum phase systems. Based on the LQ formulation, this paper shows the trade-off relation between undershoot and rising time performances in nonminimum phase systems by using a new performance index which consists of new state and tracking error. And performances of the proposed method are shown via computer simulations.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.10b
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• pp.29-35
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• 2000

As the increasing demand of the radio wave communication and teh progreessing of communication system, the radio interference of neighbor nations is rising in the improtant matter. This problem is a delicate matter which must be dealt diplomatically with by having a distinct technical basis. For our country, after the radio interference has been occurred in TRS service on the south seashore due to the base stations located at Fukuoka in Japan, the radio interference problem of neighbor nations has risen importantly. In this paper, therefore, we has measured the radio wave that reach from Fukuoka in Japan to Pusan in Korea and also collected dat by real-time.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1526-1531
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• 2007

Data transmission capacity that is required in 2010 is forecasted that increase by optical communication capacity more than present centuple, and is doing increased demand of optical communication related industry product present. Specially, Lid glass' application that is one of optical communication parts is used in optical communication parts manufacture of Fiber array, Ferrule array, Fanout Black, Silica optical waveguide chip and splitter etc. Also, it is used widely for communication network system, CATV, ATM-PON, FTTH and system. But, Lid glass need much processing times and becomes cause in rising prices of optical communication parts because production cost is expensive. The objectives, of this work is to suggest the micro concave and convex pattern manufacturing technology on borosilicate plate using high temperature and compression molding method. As a result, could developed micro pattern Mold more than 5 pattern, and reduce Lid Glass manufacture cycle time.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.264-267
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• 1995

In indirect vector control, if the value or the rotor tine constant used in slip calculation is different from the actual rotor time constant because of the temperature rising and flux saturation level, model flux angle and actual flux angle is different so that the transient and steady state response is degraded. In this paper, flux deviation angle is calculated by using actual torque and reference torque, and this flux deviation angle is summed to slip angle, therefore rotor flux angle is always accurate and indirect vector control is satisfied.