• Journal of the Korean Data and Information Science Society
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• v.26 no.3
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• pp.653-659
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• 2015

The Pythagorean formula for baseball postulated by James (1982) indicates the winning percentage as a function of runs scored and runs allowed. However sometimes, the Pythagorean formula gives a less accurate estimate of winning percentage. We use the records of team vs team historic win loss records of Korean professional baseball clubs season from 2005 and 2014. Using assumption that the difference between winning percentage and pythagorean expectation are affected by unusual distribution of runs scored and allowed, we suppose that difference depends on mean, standard deviation, and coefficient of variation of runs scored per game and runs allowed per game, respectively. In conclusion, the discrepancy is mainly related to the coefficient of variation and standard deviation for run allowed per game regardless of run scored per game.

• Journal of the Korean Data and Information Science Society
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• v.27 no.6
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• pp.1477-1485
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• 2016

The Pythagorean theorem for baseball based on the number of runs they scored and allowed has been noted that in many baseball leagues a good predictor of a team's end of season won-loss percentage. We study the convergence characteristics of the Pythagorean expectation formula during the baseball game season. The three way ANOVA based on main effects for year, rank, and baseball processing rate is conducted on the basis of using the historical data of Korean professional baseball clubs from season 2005 to 2014. We perform a regression analysis in order to predict the difference in winning percentage between teams. In conclusion, a difference in winning percentage is mainly associated with the ranking of teams and baseball processing rate.

• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.309-316
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• 2017

In baseball, estimation of winning percentage is critical and many studies for this topic have been actively performed. Pairwise winning percentage estimation using Pythagorean winning percentages of individual teams against other individual teams has the property that the sum of estimated winning percentage totals must be a constant. In this paper, we consider two types of pairwise estimation including linear formula and Pythagorean formula to the Korean baseball data of seasons from 2013 to 2016 under the criterions of RMSE and MAD. In conclusion, pairwise Pythagorean methods have the smaller RMSE and MAD than traditional Pythagorean methods. We suggest the optimal pairwise Pythagorean formula with a fixed exponent. Also we show that there are very little differences of RMSE and MAD between variation in exponent values.

• The Journal of the Korea Contents Association
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• v.16 no.9
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• pp.127-135
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• 2016

We identified a competition network which has never been studied before and investigated the relationship between centrality of participants in singing competition and their winning percentage within the competition network. We collected competition data from 'Immortal Songs: Singing the Legend', which is a Korean television music competition program, and constructed a competition network. We calculated centrality and winning percentage and analyzed their relationship using correlation analysis, regression analysis, and visualization. There are four main findings in this research. First, a competition network is a scale-free network whose degree distribution follows a power law. Second, there is a logarithmic relationship between the count of competition and closeness. Third, winning percentage converges to approximately 60% for players who have participated in more than 20 competitions. Lastly, a strength of opponents affects approximately 23% of winning percentage for players with less than 20 competitions. The academic significance of this study is that we pioneered the definition of the competition network and applied social network analysis method. Another significant contribution of this paper is that we found explicit patterns between the centrality and winning percentage, suggesting ways to improve social relationship in competition network and to increase winning percentage.

• 한국체육학회지인문사회과학편
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• v.55 no.6
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• pp.361-373
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• 2016

The winning rate is the most important indicator for running a professional baseball team because it directly affects the spectator. James(1980) suggests that the Pythagorean method is almost identical to the actual winning rate, which is known as a way of helping to establish a team strategy. In this study, it was analyzed what kind of detail difference produced difference between real winning rate and winning rate based on Pythagorean method for 10 years from 2005 to 2014. The purpose of this study is to derive a plan to improve the performance of Korean professional baseball team. The results show that the expected winning rate differs from the actual winning rate by +.062 to -.054. In the process of this result, records of base on balls of the hitter, strikeout of the hitter, base on balls of the pitcher, batting average, sacrifice fly, etc. were found to affect the performance of professional baseball team. Therefore professional baseball teams should improve their batting eye so they can get a base on balls and reduce strikeouts. In the case of a pitcher, it should be instructed to reduce the base on balls by improving the control.

• The Korean Journal of Financial Studies
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• v.8 no.1
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• pp.1-20
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• 2002

이 논문에서는 1991년 1월부터 2000년 12월까지의 납세 후 CD수익률 자료와 소비자물가지수 자료를 사용하여 우리 나라 금융시장에서 단기적 피셔효과가 존재하는지를 검증하고자 시도하였다. Fama(1975)의 방법에 따라 3개월 물가상승률을 CD수익률에 관해 회귀분석한 결과, CD수익률이 미래 물가상승률의 예측치로서 충분한 역할을 하지 못한다는 결과를 얻었다. 단기적 피셔효과를 검증하기 위하여 CD수익률을 기대물가상승률에 관하여 회귀분석하였다. 기대물가상승률은 상수 및 시간추세와 계절성을 반영하는 부분과 확률적 부분으로 구분하고, 확률적 부분이 랜돔워크 모형에 따르는 경우와 AR(1) 모형에 따르는 경우에 대해 기대물가상승률을 구하였다. 랜돔워크모형에 의해 예측하든 AR(1)에 의해 예측하든 기대물가상승률의 회귀계수는 유의한 양(+)의 값이긴 1보다는 훨씬 작은 값으로 추정되었다. 이것은 우리나라의 CD수익률에 단기 피셔효과가 부분적으로만 존재하고 있다는 것을 의미한다. 그리고 AR(1)을 사용하여 예측한 기대물가상승률이 랜돔워크모형을 사용한 경우보다 나은 추정결과를 보여주고 있다.

• Journal of the Korean Data and Information Science Society
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• v.27 no.6
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• pp.1585-1592
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• 2016

Estimation of winning percentage in baseball has always been particularly interesting to many baseball fans. We have fitted models including linear regression and Pythagorean formula to the Korean baseball data of seasons from 1982 to 2015. Using RMSE criterion for both the linear formula and the Pythagorean formula, we compared two models in predicting the actual winning percentage. Pythagorean expectation is superior to linear formula when there is either high or low winning percentage. Two methods yield very similar efficiencies when the actual winning percentage is about 50%. To understand and use for estimating winning percentage, it is easier linear formula as estimated equations.

• Journal of the Korea Society of Computer and Information
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• v.25 no.7
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• pp.39-46
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• 2020

Recently, for designing virtual characters in the battle game field effectively, some methods are very needed to predicate the win rates of the battle of them efficiently. In this paper, we propose a method to solve this problem by combining simulation and machine learning. Firstly, a simulation is used to analyze the win rates of the battle of virtual characters in the battle game. In addition, we apply a regression model based machine learning scheme to predict win rates of the battle of virtual characters according to their abilities. Our experimental results using suggested method show that it is almost no difference between the win rates of the simulation and the prediction results using the machine learning scheme. And also, we can obtain good performance in the experiment using only simple regression based machine learning model.

• The Korean Journal of Applied Statistics
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• v.24 no.1
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• pp.169-175
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• 2011

Since 2009, a new method of computing the percentage of victories is being used in the regular league of the Korean professional baseball. This method produced enormous results from the first year of application, and also had an effect on the team standings in 2010. In this paper, we have examined the effects this method had on the Korean professional baseball in 2009 and 2010. We also have discussed what the Korea Baseball Organization need to complement in using this method and suggested complementary measures.

• Journal of Korean Society of Transportation
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• v.26 no.4
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• pp.217-227
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• 2008

The purpose of this research is the estimation of a transfer ratio according to transfer time reflecting passenger attributes such as sex, age, income, job, the car ownership, and other variables with the assumption that a transfer ratio would be different depending on each passenger attribute. This research tested transfer time through a question-survey, estimated transfer time according to the passenger attributes using a data sample, and presented some applicable models about marginal transfer time for the case of the determination of transfer ratios according to transfer time. In this research the sample which had been surveyed for passengers walking to access a transfer station was used to test and estimate and the question was present walking time to the transfer time and the marginal transfer walking time.