• Journal of ILASS-Korea
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• v.28 no.2
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• pp.62-67
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• 2023

Recently, the global automobile industry is aiming for a transition from internal combustion locomotives to zero-emission vehicles. Electric vehicles powered by battery energy can operate at peak performance and improve fuel economy by applying multiple motors or multi-speed transmissions. In order to design a two-speed transmission, it is necessary to evaluate and analyze the application system and performance of electric vehicles. In this study, control performance optimization of a twostage battery electric vehicle equipped with an AMT-based automatic transmission was performed and performance according to control pattern changes was analyzed. In order to improve the operating efficiency of the motor, the shift control that sets the optimal operating point according to the vehicle speed and required torque was derived from the motor efficiency map. The performance of battery energy consumption and transmission loss energy according to the hysteresis interval was analyzed and optimized. The hysteresis interval applied to the optimal shift map acted as a factor in reducing the frequency and loss of shifts. It has been shown that keeping the hysteresis interval at about 4 km/h can reduce energy consumption while reducing the number of shifts.

• Proceedings of the Korean Society of Computational and Applied Mathematics Conference
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• 2003.09a
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• pp.7-7
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• 2003

We studied closed set-valued Choquet integrals in two papers(1997, 2000) and convergence theorems under some sufficient conditions in two papers(2003), for examples : (i) convergence theorems for monotone convergent sequences of Choquet integrably bounded closed set-valued functions, (ii) covergence theorems for the upper limit and the lower limit of a sequence of Choquet integrably bounded closed set-valued functions. In this presentation, we consider fuzzy number-valued functions and define Choquet integrals of fuzzy number-valued functions. But these concepts of fuzzy number-valued Choquet inetgrals are all based on the corresponding results of interval-valued Choquet integrals. We also discuss their properties which are positively homogeneous and monotonicity of fuzzy number-valued Choquet integrals. Furthermore, we will prove convergence theorems for fuzzy number-valued Choquet integrals. They will be used in the following applications : (1) Subjectively probability and expectation utility without additivity associated with fuzzy events as in Choquet integrable fuzzy number-valued functions, (2) Capacity measure which are presented by comonotonically additive fuzzy number-valued functionals, and (3) Ambiguity measure related with fuzzy number-valued fuzzy inference.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.1
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• pp.61-67
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• 1997

This experiment was carried out from 1979 till 1983 to elucidate the underdrainage effect on soil salinity and growth of rice plastic underdrainage was established 5m and 8m intervals in April of 1979 and Jinjubyeo the medium maturing rice variety was transplanted by hand at late of May. The results are as follow; The desalination effect was higher in 5m interval underdrainage than 8m interval underdrainage and the salt content was lower than 0.3％ at 1 year after in 5m interval, 2 years after in 8m interval underdrainage and 3 years after at control. Farther the distance from underdrainage position, less the desalinization rate that desalinization was least at center part of the underdrainage position. Desalinization effect was highest 30cm of soil depth and decreased deeper than it. Shorter the underdrainage interval, more the panicle number, heavier 1, 000 grain weight and higher the milled rice yield. But the milled rice yield wasn't significantly different between the underdrainage interval from 3 years after underdrainage.

• Journal of Preventive Medicine and Public Health
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• v.39 no.3
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• pp.213-220
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• 2006

Objectives: The purpose of this study was to examine the effect of women's late age of marriage on the interval between marriage and their first birth Methods: Data from Year 2000 Korea National Fertility Survey was collected through direct interview questionings, and the data was analyzed based on randomly selected sampling. In particular, the married women (N=5,648) were analyzed for the factors that determined the first-birth interval by performing Cox's proportional hazard model survival analysis. Results: Unlike previous findings, the woman whose age of marriage was 30 or more was more likely to delay the birth of her first baby than were the other women who married earlier. Further, a woman's age at marriage, a woman's residence before marriage, her husband's religion, her husband's level of education and the difference in age between the woman and her husband significantly influenced the first-birth interval. In contrast, for a married woman, her age, level of education, current residence and religion were not significant predictors of her first birth interval. Conclusions: Our study showed that women who married at the age of 30 years or more tend to postpone their first birth in Korea. When facing the increasing number of women who marry at a late age, the Korean government should implement population and social policies to encourage married women have their first child as early as possible.

• Journal of Industrial Technology
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• v.27 no.B
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• pp.235-243
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• 2007

Sensor network is used to obtain sensing data in various area. The interval to sense the events depends on the type of target application and the amounts of data generated by sensor nodes are not constant. Many applications exploit long sensing interval to enhance the life time of network but there are specific applications that requires very short interval to obtain fine-grained, high-precision sensing data. If the number of nodes in the network is increased and the interval to sense data is shortened, the amounts of generated data are greatly increased and this leads to increased amount of packets to transfer to the network. To transfer large amount of packets fast, it is necessary that the delay between successive packet transmissions should be minimized as possible. In Sensor network, since the Operating Systems are worked on the event driven, the Timer Event is used to transfer packets successively. However, since the transferring time of packet completely is varies very much, it is very hard to set appropriate interval. The longer the interval, the higher the delay and the shorter the delay, the larger the fail of transfer request. In this paper, we propose ESTEO which reduces the delay between successive packet transmissions by using SendDone Event which informs that a packet transmission has been completed.In ESTEO, the delay between successive packet transmissions is shortened very much since the transmission of next packet starts at the time when the transmission of previous packet has completed, irrespective of the transmission timee. Therefore ESTEO could provide high packet transmission rate given large amount of packets.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.2
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• pp.168-173
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• 2015

The flight control of aircraft, which has nonlinear time-varying dynamic characteristics depending on the various and unexpected external conditions, can be performed on two motions: longitudinal motion and lateral motion. In the longitudinal motion control of aircraft, pitch and trust are major control parameters and roll and yaw are control ones in the lateral motion control. Until now, a number of efficient and reliable control schemes that can guarantee the stability and maneuverability of the aircraft have been developed. Recently, the intelligent flight control scheme, which differs from the conventional control strategy requiring the various and complicate procedures such as the wind tunnel and environmental experiments, has attracted attention. In this paper, an intelligent longitudinal control scheme has been proposed utilizing Interval Type-2 fuzzy logic which can be recognized as a representative intelligent control methodology. The results will be verified through computer simulation with a F-4 jet fighter.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.5
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• pp.632-636
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• 2005

This study was conducted to investigate the effects of removal of all ovarian follicles through repeated transvaginal follicle aspiration (TVFA) on the subsequent follicular populations in buffaloes. This information is crucial for determining the optimum time interval between successive aspirations for recovering oocytes from live buffaloes through Transvaginal Oocyte Retrieval (TVOR). The oestrus of cycling buffaloes (n=5) were synchronized by a single PGF injection schedule. All the ovarian follicles were removed once every 7 days for 6 weeks through TVFA, starting from Day 7 of the oestrous cycle (Day 0 = day of oestrus). The number and size of individual ovarian follicles was recorded at Day 3 and Day 5 (Day 0 = day of TVFA) through transrectal ultrasonography. The follicles were classified on the basis of their diameter as small (3-5 mm), medium (6-9 mm) and large ($\geq$10 mm). There was no difference in the number of small and medium follicles, and the number of total follicles between Day 3 and Day 5. However, the number of large follicles was significantly higher (p<0.05) at Day 5 than that at Day 3. There was a significant (p<0.05) decrease in the proportion of small follicles and an increase (p<0.05) in the proportion of large follicles from Day 3 to Day 5, with no change in the proportion of medium follicles. The number of total follicles at Day 3 or Day 5 did not differ during the 6 TVFA sessions. It can be concluded that an interval of 3 days is more suitable than that of 5 days between successive aspirations for recovering oocytes through TVOR in a twice weekly schedule and that repeated removal of follicles through TVFA does not adversely affect the number of total follicles 3 or 5 days after TVFA.

• The Mathematical Education
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• v.50 no.2
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• pp.135-148
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• 2011

We can say that the history of mathematics is the history on the development of the number system. The number starts from Natural number and is constructed to Integer number and Rational number. The Rational number is not the complete number analytically so that Real number is completed by the idea of the nested interval method. Real number is completed analytically, however, is not by algebra, so the algebraically completed type of the rational number, through the way that similar to the process of completing real number, is Complex number. The purpose of this study is to show the most appropriate way for the development of the human being thinking about the teaching and leaning of Complex number. To do this, We have to consider the proof of the existence of Complex number, the background of the introduction of Complex number and the background knowledge that the teachers to teach Complex number should have. Also, this study analyzes the knowledge to be taught of Complex number based on the anthropological theory of didactics and finally presents the teaching method of Complex number based on this theory.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.234-239
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• 2010

The irrigation interval and time for the supply of nutrient and water to the plant is important in the aeroponic system. This study was conducted to investigate the effect of irrigation interval on the growth of Phalaenopsis hybrid seedlings in the aeroponic system. Young bare-root plants (four leaves, 16 g in fresh weight) were used for this experiment. The composition of nutrient solution was, in $me{\cdot}L^{-1}$, 9 N, 3 P, 4 K, 4 Ca and 2 Mg. The electrical conductivity (EC) and pH of nutrient solution used was $1.2\;dS{\cdot}m^{-1}$ and 5.8, respectively. Irrigation intervals were 10, 20, 30, 40, and 50 minute and each irrigation time was 10 minute. The total fresh and dry weight, the number of branched roots, and relative growth rate at the 20 and 30 min. was greater than 10, 40, 50 min. interval. Especially, the fresh weight of roots at 30 min. interval was the highest. Leaf length was the highest at 30 min. interval but there was no difference in leaf width. The amount of water consumed for a month was 0.71 L per plant and it was reduced with increasing irrigation interval. There was no difference in the amount of consumed mineral contents for 15 days except for potassium. Potassium absorbed was the highest at 30 min. irrigation interval. As a result, the optimum irrigation interval was 30 min for the production of Phalaenopsis hybrid seedlings in the aeroponic system.

• Bulletin of the Korean Mathematical Society
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• v.52 no.4
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• pp.1241-1252
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• 2015

In this paper, we study the dynamical bifurcation of the modified Swift-Hohenberg equation on a periodic interval as the system control parameter crosses through a critical number. This critical number depends on the period. We show that there happens the pitchfork bifurcation under the spatially even periodic condition. We also prove that in the general periodic condition the equation bifurcates to an attractor which is homeomorphic to a circle and consists of steady states solutions.