• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.11 no.2
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• pp.15-29
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• 2007

In this paper, we explore some interesting models of the quasi-negative-binomial distribution based on difference differential equations applicable to theory of microorganisms and the situations like that. Some characterizations based on conditional distributions and damage process have been obtained. Further, the distribution of number of accidents as the quasi-negative-binomial distribution in the light of Irwin's theory of ";proneness-liability"; model has been derived. Finally, the proposed model (QNBD) has been applied to study the Shunting accidents, home injuries, and strikes in industries.

• Journal of Aquaculture
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• v.13 no.1
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• pp.13-19
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• 2000

A genetic analysis of reproductive characters of masu salmon at three year classes was described. the reproductive performance of masu salmon spawning at 2 years of age was analyzed using data number fertility hatchability and growth traits to the juvenile stage. The phenotypic correlations among the traits were also estimated. it was determined that egg volume was the principle deter-minant of egg number and that the relationship of number to size was negative. It is recommended that selection for egg size be included in all selection programs and egg number be ignored in any welection program designed to increase body size. Phenotypic correlations between body size of parents and egg traits as well as between body size of offspring and egg traits were not significantly positive or negative magnitude at three year classes.

• The Mathematical Education
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• v.42 no.3
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• pp.265-274
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• 2003

To learn number system is a basic thing in school mathematics. In this paper, we analyze how number system is introduced in the 7th national curriculum and text books according to it. We found that the method of introducing number system is quite different from the former curriculum and former text books. There are many negative effects on the transition when compared with those of United States of America. There are many gaps between elementary school mathematics and middle school mathematics about levels and skills to deal with numbers. It is desirable to distinguish the negative sign from subtraction and to keep the concepts of commutativity and associativity of operations from the beginning. We also suggest to change the introducing timing and extension methods of number system in 7th grade mathematics.

• Journal of the Korean Society of Safety
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• v.26 no.5
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• pp.130-135
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• 2011

This study deals with the accident models of arterial road sections. The objectives is to develop the models by number of lane. In pursuing the above, this study gives particular emphasis to dividing the 474 small link sections, collecting the accident data of 2007, and applying the statistical programs of SPSS17.0 and NLOGIT4.0. The main results are as follows. First, the number of accidents of two-lane roads were analyzed to be 59.9% of totals and to be the most of all. Second, one Poisson and two negative binomial regression models which were all statistically significant were developed. Finally, the common variables of all models were evaluated to be ADT and number of exit/entry which were all positive to the accidents.

• Journal of Industrial Convergence
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• v.1 no.1
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• pp.25-40
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• 2003

A number of recent studies have contributed to an increased understanding of how and why workers feel bound to their unions. However, by now there has been limited theoretical works on the various forms that union membership can take. Thus, the goal of this study is to develop the types of union membership. To develop the types of union membership, I used the ideological and instrumentalitic concepts. The types of union membership are identified as follows: Positive free agents (${\Leftrightarrow}$ Negative free agents) have low levels of both positive (negative) instrumentality and positive (negative) ideology. If positive (negative) instrumentality is high and positive (negative) ideology low, this group may be labeled Instrumentals (${\Leftrightarrow}$Disgruntled). Expressives (${\Leftrightarrow}$Antagonizers) have low levels of positive (negative) union instrumentality and high levels of positive (negative) ideology. Those who have high levels of both positive (negative) ideology and positive (negative) instrumentality have been called Identifiers (${\Leftrightarrow}$Opponents). Variables related to union instrumentality, and union ideology were investigated: (1) the personal characteristics of individual members, (2) the employing organization, (3) the union characteristics, (4) the economic environment, (5) the labor relations climate.

• Communications for Statistical Applications and Methods
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• v.8 no.3
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• pp.667-675
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• 2001

The usefulness of analysis of variance(ANOVA) estimates of variance components is impaired by the frequent occurrence of negative values. The probability of such an occurrence is therefore of interest. In this paper, we investigate a variety of reasons for negative estimates under one way random effects model. It can be shown, through simulation, that this probability increases when the number of treatments is too small for fixed total observations, unbalancedness of data is severe, ratio of variance components is too small, and data may contain many outliers.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.295-303
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• 2019

This study investigated the effects of various cultivation pots on Betula platyphylla var. japonica seedlings in order to select suitable pots for the production of healthy seedlings for the ecological revegetation. We used six types of the pots natural pot, natural pot with inside 5 mm width root turning bump, natural pot with inside 10 mm width root turning bump, negative-phototropism pot, negative-phototropism pot with inside 5 mm width root turning bump, and negative-phototropism pot with inside 10 mm width root turning bump. As greenhouse cultivation provided a high level of control of irrigation and temperature, the seedlings did not show any significant differences in plant height, number of branches, and diameter at root collar, but showed a significant difference in root growth among the different types of pots. The root growth was best in the negative-phototropism pot. In the negative-phototropism, the roots grew in a vertical shape, while they grew abnormally in a spiral shape in the natural pots. In outdoor cultivation, the growth of seedlings showed significant differences according to container types. The seedlings grown in specially manufactured negative-phototropism pots were most excellent in all of the height, number of branches, diameter at root collar and root growth. As for the seedlings grown in the negative-phototropism pots, their roots grew vertically and thus their rooting was well established after they were transplanted outdoor. A size of less than 5 mm ridge installed in the negative-phototropism was found to be appropriate for the seedling growth. These results showed that the negative-phototropism pot would be best suitable for the growth of Betula platyphylla var. japonica seedlings and for the production of seedling for ecological revegetation.

• Journal of the Korean Data and Information Science Society
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• v.26 no.2
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• pp.387-397
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• 2015

In this paper, the determinants of the number of job changes in the SMEs (small and medium enterprises) youth-intern project is analysed, utilizing SMEs youth-intern DB and employment insurance DB. Since the number of job changes are count data which take integer values other than negative values, general linear regression analysis becomes inappropriate. Therefore, four models such as Poisson regression model, zero inflated Poisson regression model, negative binomial regression model and zero inflated negative binomial regression model are tried to fit count data. A zero inflated negative binomial regression model is selected to be the best model. Major results are the followings. First, the number of job changes is shown to be significantly smaller in the treatment group than in the control group. Second, the number of job changes turns out to be significantly smaller in the young-age group than in the old-age group. Third, it is also shown that the number of job changes of man is significantly greater than that of woman. Lastly, the number of job changes in the bigger firm is shown to be significantly less than that of the smaller firm.

• Human Ecology Research
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• v.55 no.1
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• pp.13-26
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• 2017

This study investigated the latent groups depending on married working women's work-family spillover. The effects of factors that determine mental health subgroups and differences were also analyzed. Mixture modeling was applied to the Korean Longitudinal Survey of Women & Families to achieve the research objectives. The major findings of this study were as follows. First, there were four subgroups that could be defined according to the work-family spillover: mid-level spillover group (mid-positive and mid-negative spillover group), high-level spillover group (high-positive and high-negative spillover group), low-level spillover group (low-positive and low-negative spillover group), and high-negative and low-positive spillover group. Second, the results of mixture regression analysis to test the effect of eco-system variables showed that age, academic background, non-traditional family value, number of children, work hours, wage income, and availability of the maternity leave were significant determinants of the latent groups. The probability of classifying in the high-negative and low-positive spillover group increased when women showed a lower academic background and wage income, higher number of children and older age, and longer work hours than others. Third, the high-level spillover group, and the high-level spillover group showed the lowest stress and the lowest depression; however, the low-level spillover group reported the highest stress and the highest depression. Implications, limitations, and future directions were discussed based on the results.

• Asia Marketing Journal
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• v.24 no.2
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• pp.62-77
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• 2022

Seeded marketing campaign (SMC) is a newly created type of marketing activities with the widespread use of social media. Previous research has examined to find out the optimal seeding strategy that yields the best outcome from the campaign. This research explores the relationships between the characteristics of the seeded influencer and user engagement. The data consists of information from 1062 seeded Instagram posts posted in September 2020 in Korea and 778 seeded influencers who posted those contents. Analyzed by negative binomial regression, our quadratic model suggests that the relationship between user engagement and the number of followers of the seeded influencer draws an inverted U-shape, indicating influencers with greater number of followers may not always be the best choice for the marketers. Moreover, this research shows that the negative marginal impact coming from the huge number of followers can be attenuated when the influencer is an expert of the seeded product.