• Journal of Animal Science and Technology
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• v.53 no.4
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• pp.319-324
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• 2011

This study was conducted to analyze demerits of the sire evaluation system using annual earnings and to examine relationship between annual earnings and finish time in home-produced thoroughbred racehorses. The average number of progenies and number of starts per sire were 34 heads and 221 times, respectively. On the other hand, the number of progenies with the average age of 2 years and the number of starts were 9 heads and 25 times, respectively. The earnings of the horses with the age of 2 years accounted for 8.3% of annual earnings. The simple correlation coefficient between the number of progenies and the number of starts in annual earnings were 0.922 and 0.934, respectively. The correlation coefficient between the number of progenies and the number of starts was very high (0.985). The number of progenies and starts of sires for the first year of test career were very low (6 heads and 17 times), and there was very close relationship between number of progenies and annual earnings by the year of test career. The number of progenies was over 40 heads during the first 4 years of test career, and as the number of progenies increased the average earning index increased. The average earning index of sires with less than 30 progenies was lower than 1.00. When the number of progenies was less than 10, the average earning index was in the range of 0.06~0.13, indicating that the number of progenies affects much for determining the ranking of sires. The correlation coefficient between breeding value for finish time and annual earnings per start was very high (-0.524~-0.633) compared with other traits.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.1
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• pp.141-149
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• 1999

In this paper, we consider multiple-class queueing systems in which the server starts a set-up as soon as the number of customers in the "start-up class" reaches threshold N. After the set-up the server starts his service. We obtain the Laplace-Stieltjes transform and the mean of the waiting times of each class of customers for FCFS and non-preemptive priority disciplines.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.55-60
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• 2016

In the traditional wireless LAN model, scan procedure to search a new AP starts when the predefined number of Rx failure of beacon frames are occurred. In this case, lots of data packet loss occur during MN's handover because loss of the relatively longer data packet starts before the small-sized beacon loss. Newly developed scanning mechanism in this paper has the beacon counter that increases when the Rx power level of beacon frame is less than the threshold and the previous rx power level. New scan procedure starts when the counter exceeds the predefined number. Beacon Rx power threshold is verified and performance of the new WLAN model is evaluated under UDP and TCP traffic environment.

• Korean Management Science Review
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• v.25 no.3
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• pp.27-43
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• 2008

This study analyzes the changes of Gyeongju local society because of setting up low and intermediate level radioactive waste disposal site by using urban dynamics model. Specifically, after examining 'Gyeongju Long-Term Development Plan' announced in 2007, I establish the number of industries, population, gross local product, residents' income, and the long term employment condition as essential change-causing factors in Gyeongju local society based on the Big3 government project, and forecast it by using 'Gyeongju long-Term Development Plan' and all sorts of statistical data. In this stage, I assume 3 scenarios(basic, optimistic, and pessimistic view) to estimate the changes of local society more exquisitely, and scenarios are composed through mediation about variables of a growth rate and an inflow or outflow rate. The result shows that Gyeonaju local society would have growing changes by 2020. The essential change-causing factors are as follows. The case of population is estimated that it starts going down at the level of approximately 270 thousand by 2009, starts going up continuously after 2009, the year of completion of low and intermediate level radioactive waste disposal site, and increases from the level of about 300 thousand as minimum to 340 thousand as maximum in 2020. The estimates of other cases are made that the number of Industries has about 10 thousand increases, gross local product has almost 6 trillion increases, nominal gross national income doubles, as well as residences have approximately 280 thousand increases, and also made that employment condition also improves continuously, and diffusion ratio of house starts going up but the amount of supplies is a little bit insufficient in the long view.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.66
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• pp.11-18
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• 2001

In this paper, we analyze an M/G/1 two-phase gated service model with threshold. We consider compound Poison arrival Process and general service time, where the server fives two different modes of services in order, batch and individual services. Server starts his service when the number of arrived customers reaches the predetermined threshold . We find the PGF of the number of customers in system and LST of waiting time, with which we obtain the means of them.

• Journal of the Korean Society of Safety
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• v.37 no.6
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• pp.32-39
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• 2022

This study analyzed the relationship between occupational accidents in the construction industry and business cycle factors. Multiple regression analyses were conducted to achieve the research purpose; additionally, time-varying parameter estimations were performed to interpret the results. The results obtained for the construction industry revealed a statistically significant relationship between occupational accidents and wage increase rate, unemployment, construction starts, and other factors. The wage increase rate plays a role in reducing occupational accidents because efforts are made to prevent accidents owing to the increase in income loss due to accidents and the demand for increased safety levels. The number of construction starts affects occupational accidents with a time lag of 1 to 2 or 4 months; therefore, it is likely to be used as a leading indicator for estimating fatal accidents in the construction industry. This study highlighted the importance of monitoring socioeconomic changes that could affect the working conditions of workers and workplaces, and production activities in the workplace for the effective prevention of occupational accidents. This study also reveals the necessity of developing a method to operate prevention projects flexibly and the seasonality of industrial characteristics, particularly those of the construction industry where the highest number of fatal occupational injuries occur.

• Journal of Mechanical Science and Technology
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• v.14 no.9
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• pp.913-919
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• 2000

The purpose of this study was to develop a new element removal method for ESO (Evolutionary Structural Optimization), which is one of the topology optimization methods. ESO starts with the maximum allowable design space and the optimal topology emerges by a process of removal of lowly stressed elements. The element removal ratio of ESO is fixed throughout topology optimization at 1 or 2%. BESO (bidirectional ESO) starts with either the least number of elements connecting the loads to the supports, or an initial design domain that fits within the maximum allowable domain, and the optimal topology evolves by adding or subtracting elements. But the convergence rate of BESO is also very slow. In this paper, a new element removal method for ESO was developed for improvement of the convergence rate. Then it was applied to the same problems as those in papers published previously. From the results, it was verified that the convergence rate was significantly improved compared with ESO as well as BESO.

• Speech Sciences
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• v.11 no.2
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• pp.237-245
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• 2004

In general, Gaussian mixture model(GMM) is used to estimate the speaker model for speaker identification. The parameter estimates of the GMM are obtained by using the expectation-maximization (EM) algorithm for the maximum likelihood(ML) estimation. However, if the number of mixtures isn't defined well in the GMM, those parameters are obtained inappropriately. The problem to find the number of components is significant to estimate the optimal parameter in mixture model. In this paper, to estimate the optimal number of mixtures, we propose the method that starts from the sufficient mixtures, after, the number is reduced by investigating the mutual information between mixtures for GMM. In result, we can estimate the optimal number of mixtures. The effectiveness of the proposed method is shown by the experiment using artificial data. Also, we performed the speaker identification applying the proposed method comparing with other approaches.

• 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.

• Bulletin of the Korean Mathematical Society
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• v.54 no.3
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• pp.1069-1080
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• 2017

The Tribonacci sequence ${\{T_n}\}_{n{\geq}0}$ resembles the Fibonacci sequence in that it starts with the values 0, 1, 1, and each term afterwards is the sum of the preceding three terms. In this paper, we find all integers c having at least two representations as a difference between a Tribonacci number and a power of 2. This paper continues the previous work [5].