• Restorative Dentistry and Endodontics
• /
• v.15 no.2
• /
• pp.115-121
• /
• 1990

Forty extracted human mandibular second molars with C-shaped canal were chosen to study the anatomy of the root canal. The experimental teeth were injected with china ink, decalcified and cleared with Winter green oil, in vitro, to study the number of root, root canal, canal per root, frequency and location of lateral canal and transverse anastomosis. 1. All teedth had one root. 2. Mesial roots with two canals were 25%, and mesial roots with one canal were 75%. All distal roots had one canal. 3. In the roots with two canals, the common apical foramen appeared in 20% and the separte apical foramen appeared in 80%. 4. The frequence of lateral canal was 33.3% and the most frequent region was middle 1/3. 5. All teeth had the transverse anastomosis in all region of the roots.

• Herbal Formula Science
• /
• v.19 no.2
• /
• pp.1-10
• /
• 2011

Objectives : Since its enactment in 1987, the 56 standard prescriptions covered by insurance have remained unchanged from its original version. In this study, we tried to discover most frequently used herbal combinations by analyzing prescriptions used in actual clinical settings. Methods : We have built Structured Query Language to analyze herbal combination and progressed this analysis through analyzing the frequencies of medicinal herb combinations in medical prescription slips. Results : We have found out that traditional Korean medical doctors use about 13 herbs in a prescriptions and usually use 253 kinds of herb. And We have found out the most frequently used herbal combination. Conclusions : In this study, We can suggest new method to decide what do we need on insurance prescriptions.

• Transactions of The Korea Fluid Power Systems Society
• /
• v.4 no.2
• /
• pp.28-33
• /
• 2007

In the power plant facility which use soft coal as a power source the fan pitch blade control hydraulic actuator is used to control the inlet and outlet gas to regulate the internal pressure of the furnace and control the frequence. Sometimes malfunctions of this equipment lead to the decline of boiler thermal efficiency and unexpected power plant trip. In order to localize the fan pitch blade control hydraulic actuator specially for the 500MW large scale boiler, Analysis and modelling of the system is carried out mathematically. The responses of the system are examined by using matlab simulation fur the variation of the major parameters in view of reverse engineering. Consequently the validity of the established parameters are examined.

• The Korean Journal of Quaternary Research
• /
• v.7 no.1
• /
• pp.103-111
• /
• 1993

Apres le Perigordien ancien, les proportions de l'outillage archaique du Prerigordien decroissent progressivement au fur et a mesure que les industries perigordiennes se developpent. Dans le Perigordien superieur ( couche Ⅵ du Flageolet I ) les outils archaiques sont beaucoup moins frequents que dans le Perigordien ancien, mais ils perdurent encore en proportion notable et leur indice atteint 31,23. Par la suite, dans le Perigordien superieur evolue la frequence de l'outillage archaique est naturellement la plus faible pour le Perigordien et 1'indice moyen d'outils archaiques y descend a 17,99.

• Journal of environmental and Sanitary engineering
• /
• v.16 no.1
• /
• pp.9-17
• /
• 2001

During the period from Jan. to Dec. 1998 and Yellow Sand phenomena, dustfall samples were collected by simple deposit jar and petridish, and calculation of passage amounts of Yellow Sand by the utilization of environmental air monitoring 4 stations from 1995 to 1998 in Seoul. Passage amounts of Yellow Sand were estimated 3,024 ton in 1995, 367 ton in 1996, 105 ton in 1997 and 3,444 ton in 1998 respectively. The highest passage amount of Yellow Sand was marked 3,444 ton in 1998 that is related to frequence of appearance. Average deposition of dusfall was $6.570{\;}ton/\textrm{km}^2$/month during the sampling periods, while average deposition of dusfall in Yellow Sand phenomena was $53.68{\;}ton/\textrm{km}^2$/month which was 8 times higher than average deposition.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.10a
• /
• pp.701-703
• /
• 2014

The intense noise generated by military aircraft hans a significant impact on ground crews and their families on airbase. For minimizing the impact of the aircraft noise on the airport, appropriate indoor noise standard is required. This paper studied to establish the indoor noise standard on the military airport. The aircraft noise was measured and analyzed the frequence characteristics. the remodeling of office for the noise mitigation was enforced to verify the appropriate internal noise standard and to select the method of reinforcement. The noise standard was classified three categories according to the dwelling, office and usage of building with flight train facilities and banishment in military airfield.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.11 no.2
• /
• pp.196-202
• /
• 2003

The object of this article is to study the plausibility of applying human voice warning system to automobiles. Human voice is considered the best tool for warning system in automobiles. For the purpose of comprehending the specific characteristics of relation between noises and properties of the automobiles indoors and voice warning system researcher performed FRF test in order to examine the characteristics of voice output, and FEM simulation to learn the specific properties of the car indoors. And furthermore, surveyed the quality of voice output, using the written inquiry to examine members. The result of the study shows that it is much possible to apply voice warning system to automobiles.

• Proceedings of the KIEE Conference
• /
• 1988.07a
• /
• pp.713-716
• /
• 1988

To characterize the bioloical tissues, the new methods to measure the frequency dependent attenuation are presented in this paper. In general, ultrasonic phase information was assumed by linear function of the frequency. But the minimum phase function which characterizes the frequency dispersion of tissue was derived in (2). It is very significant to measure the attenuation by using the minimum phase function to characterize the frequence dispersion of tissue. Also, we propose the phase correcting technique to take advantage of the idea that the distortion of amplitude component when the wave propagates through media.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.9C
• /
• pp.1252-1257
• /
• 2004

This paper presents a decentralized LQ-PID controller for the TITO system which satisfies the performance of good command following, disturbance rejection, and sensor noise reduction that is design specifications in the frequency domain The procedure is developed by establishing the relationship between the closed-loop state equations including the decentralized PID tuning parameters and the closed-loop state equations of LQR and by selecting the weighting factors Q and R of the cost function in order to satisfy the design specifications in the frequency domain.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.954-955
• /
• 2006

SFC(Static Frequence Converter)system has come to be used as start-up drive system for large synchronous machine in many industry applications. Many papers have been presented the control algorithm for pumped storage power generation using SFC system but they did not included about the detailed start-up algorithm of gas turbine using SFC system. This paper presents the important field weakening control algorithm of a large synchronous machine using SFC system and the results of experiment show that the proposed algorithm is proper and effective about this.