• Journal for History of Mathematics
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• v.16 no.3
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• pp.109-114
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• 2003

In this paper, we deal with partially conformal geodesic transformations in Kahler geometry by using Fermi coordinates when tile submanifold is a geodesic sphere. We derive the necessary and sufficient condition for tile existence of such transformation in terms of the Jacobi operator and its derivative.

• Journal of the Korean Data and Information Science Society
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• v.26 no.1
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• pp.77-87
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• 2015

Parrondo paradox is the counter-intuitive phenomenon where two losing games can be combined to win or two winning games can be combined to lose. In this paper, we consider an ensemble of players, one of whom is chosen randomly to play game A' or game B. In game A', the randomly chosen player transfers one unit of his capital to another randomly selected player. In game B, the player plays the history-dependent Parrondo game in which the winning probability of the present trial depends on the results of the last two trials in the past. We show that Parrondo paradox exists in this redistribution model of the history-dependent Parrondo game.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.15
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• pp.6243-6247
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• 2015

Background: Thyroid cancer (TC) is a more common endocrine malignancy in females and is a major cause of death in developing countries. Therefore the aim of this study was to explore possible risk factors of thyroid cancer in females of Pakistan. Materials and Methods: This study covered 232 females, including 127 (54.7%) cases and 105 (45.2%) controls, from the INMOL Hospital and Sheikh Zayed Hospital, Lahore. Different risk factors were explored by the descriptive and inferentially statistics. Odds ratios and 95% confidence intervals for different risk factors were computed using logistic regression. Results: The results showed six risk factors, marital status, family history of thyroid cancer, iodine in the diet, oxidative stress, fast food and fried food, to demonstrate positive significant links to thyroid cancer (odds ratios and 95% confidence intervals of :2.152, 1.104-4.198; 2.630, 1.416-4.887; 2.391, 1.282-4.458; 4.115, 2.185-7.750; 3.656, 1.851-7.223; 2.357, 1.268-4.382; and 2.360, 1.199-4.643, respectively). Conclusions: The Oxidative stress, marital status, family history of cancer, fast food, use of iodine diet and fried food are the risk factors of thyroid cancer in females.

• Journal of Elementary Mathematics Education in Korea
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• v.1 no.1
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• pp.53-65
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• 1997

There are many mistakes when we estimate probability of an event, for example, we often omit some likelihoods (of an event), sometimes give too large or too small possibility for a particular case, cannot relate current cases with which were concerned before, apply at another cases as soon as discuss about it insufficiently, etc. If we go into a history of probability and statistics, we shall ascertain that many scientists and mathmaticians made essentially same mistakes with us. In the paper, we will consider the theorization of probability and statistics as a process of modification of mistakes which were made during one's estimating possibility of an event. On that point of view, we shall look at historical background of probability and statistics.

• The Korean Journal of Applied Statistics
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• v.27 no.1
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• pp.133-146
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• 2014

The United States Census Bureau released a new version of X-13ARIMA-SEATS that integrates X-12-ARIMA with TRAMO-SEATS. This paper compares a seasonal adjusted series from X-13ARIMA-SEATS and those from X-12-ARIMA. An X11 filter and SEATS filter were used for the X-13ARIMA-SEATS. The result of the comparison suggests that seasonal adjusted series using X-13ARIMA-SEATS with the X11 filter are similar to those of X-12-ARIMA.

• The Korean Journal of Applied Statistics
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• v.29 no.6
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• pp.1007-1023
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• 2016

This paper explores the conditions and potential of newly designed and tried methodology of big data analysis that apply to Korean history subject matter. In order to advance them, we need to pay more attention to quantitative analysis methodologies over pre-existing qualitative analysis. To obtain our new challenge, I propose 'digital history' methods along with associated disciplines such as linguistics and computer science, data science and statistics, and visualization techniques. As one example, I apply interdisciplinary convergence approaches to the principle and mechanism of elite reproduction during the Korean medieval age. I propose how to compensate for a lack of historical material by applying a semi-supervised learning method, how to create a database that utilizes text-mining techniques, how to analyze quantitative data with statistical methods, and how to indicate analytical outcomes with intuitive visualization.

• Communications for Statistical Applications and Methods
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• v.15 no.5
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• pp.737-752
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• 2008

About 1800, mathematicians combined analysis of error and probability theory into error theory. After developed by Gauss and Laplace, error theory was widely used in branches of natural science. Motivated by the successful applications of error theory in natural sciences, scientists like Adolph Quetelet tried to incorporate social statistics with error theory. But there were not a few differences between social science and natural science. In this paper we discussed topics raised then. The problems considered are as follows: the interpretation of individual man in society; the arguments against statistical methods; history of the measures for diversity. From the successes and failures of the $19^{th}$ century social statisticians, we can see how statistics became a science that is essential to both natural and social sciences. And we can see that those problems, which were not easy to solve for the $19^{th}$ century social statisticians, matter today too.

• Journal for History of Mathematics
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• v.13 no.1
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• pp.1-14
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• 2000

The first part of this thesis discusses the Pearson's Curve Family which gives $\beta$distribution, $\Gamma$-distribution, $X^2$-distribution and t-distribution. The second part of this thesis gives some brief process of calculations for normal distribution density and t-distribution density by the 7-th type Curve of Pearson's Curve Family. Finally, a conclusion arrives that Student(Gosset) could not find out his famous 'Student's t-distribution' without his attending of 'Pearson's Differential Equation' class taught by Pearson himself when he was a senior student. However, if he had got a professorship at the Pearson Statistics Laboratory, the University of London, then he could not have found 'Student's t-distribution' for small sampling technique of modern statistics.

• Journal for History of Mathematics
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• v.15 no.1
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• pp.135-146
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• 2002

In this paper, we demonstrate that one can teach conditional probability in a manner consistent with many features of the statistics education reform movement. Presenting a variety of applications of conditional probability to realistic problems, we propose that interactive activities and the use of technology make conditional probability understandable, interactive, and interesting for students at a wide range of levels of mathematical ability. Along with specific examples, we provide guidelines for implementation of the activities in the classroom and instructional cues for promoting curiosity and discussion among students.

• ALGAE
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• v.20 no.4
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• pp.325-331
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• 2005

Populations of Campylaephora borealis (Nakamura) Seo, Cho et Boo and C. crassa (Okamura) Nakamura show a year-around occurrence of all life-history stages. Such a concurrency of life-history stages produces problems in recognizing species in the field. Here, we invesitgated the morphological variation and life-history stages of both species using a statistical character analysis. Life-history stage was correlated with the seawater temperature in C. borealis, whereas it was dependant on biomass in C. crassa. Thalli had dichotomous branches with adaxial branchlets. The statistics showed that the seasonal change in morphology of C. borealis was significantly different from that of C. crassa in seven qualitative characters and five quantitative characters (p < 0.001), although six quantitative features including tetrasporangial size were similar in both species. The morphological difference between the two species may be due to the annual variation of branchlet number and the variance of branch subangle.