• Journal of Korean Society for Quality Management
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• v.34 no.1
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• pp.73-77
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• 2006

In this paper, the Bayesian procedure for the multiple test of fraction nonconforming, p, is proposed. It is the procedure for checking whether the process is out of control, in control, or under the permissible level for p. The procedure is as follows: first, setting up three types of models, $M_1:p=p_0,\;M_2:pp_0$, second, computing the posterior probability of each model. and then choosing the model with the largest posterior probability as a model most fitted for the observed sample among three competitive models. Finally, the simulation study is performed to examine the proposed method.

• Communications for Statistical Applications and Methods
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• v.16 no.2
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• pp.363-372
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• 2009

The difference of two independent binomial proportions is frequently of interest in biomedical research. The interval estimation may be an important tool for the inferential problem. Many confidence intervals have been proposed. They can be classified into the class of exact confidence intervals or the class of approximate confidence intervals. Ore may prefer exact confidence interval s in that they guarantee the minimum coverage probability greater than the nominal confidence level. However, someone, for example Agresti and Coull (1998) claims that "approximation is better than exact." It seems that when sample size is large, the approximate interval is more preferable to the exact interval. However, the choice is not clear when sample, size is small. In this note, an exact confidence and an approximate confidence interval, which were recommended by Santner et al. (2007) and Lee (2006b), respectively, are compared in terms of the coverage probability and the expected length.

• Journal of information and communication convergence engineering
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• v.8 no.6
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• pp.660-664
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• 2010

This paper proposes a backoff control scheme for guaranteeing fair packet transmissions in TDMA wireless networks. In order to maximize the system performance, the number of packets transmitted in a frame should be kept at a proper level. In the proposed scheme, the base station calculates the packet transmission probability according to the offered loads and then broadcasts to all the mobile stations. Mobile stations attempt to transmit a packet with the received probability. Simulation results show that the proposed scheme can offer better system throughput and delay performance than the conventional one regardless of the offered loads.

• Journal of Satellite, Information and Communications
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• v.8 no.1
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• pp.66-70
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• 2013

In this paper, Threshold setting method is proposed to improve detection probability for cooperative sensing. Even if cooperative users have all same false alarm rate, each user has different threshold due to pass ad-hoc channel. threshold level is related to detection probability. So, we select the highest threshold among cooperative users and then share threshold information for getting the high detection probability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10A
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• pp.982-987
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• 2006

In this paper, ranging code collision probability and ranging period which are two important performance measures for code division multiple access (CDMA)-type ranging in wireless broadband (WiBro) system are mathematically derived. Based on the analysis, the appropriate ranging management solution for maintaining the ranging collision probability below a certain threshold level and correctly recognizing the transmitted ranging code against propagation delay is obtained in terms of the number of ranging codes, the number of ranging regions, and ranging period. In this analysis, user mobility features such as speed and moving direction are also considered.

• Journal of Korean Society for Quality Management
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• v.46 no.1
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• pp.95-112
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• 2018

Purpose: To find out the appropriate probability distribution of credit card usage behavior by considering the relationship among income, expenditure and credit card usage amount. Such relationship is enabled by Korea's especially high penetration of credit card. Method: Goodness-of-fit test and effect size statistic W were used to identify the distribution of income and credit card usage amount. A simulation model is introduced to generate the credit card transactions on individual user level. Result: The three data sets for testing had either passed the chi-square test or showed low W values, meaning they follow the exponential distribution. And the exponential distribution turned out to fit the data sets well. The r values were very high. Conclusion: The credit card usage behavior, denoted as the counts of users by usage amount band, follows the exponential distribution. This distribution is easy to manipulate, has a variety of applications and generates important business implications.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 1992.11a
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• pp.45-51
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• 1992

The purpose of this study was to predict the spatial housing demand of households in Seoul with the use of residential choice probabilitics. An multinomial legit model is developed using socio-demographic and housing characteristics. SAS package was utilized to estimate this model. This study used the data obtained by the Korea Rosearch Institute for Human Settlemente in 1989. The sample size was 3941 households in Seoul.The residential choice probability varicd depending upon the residential area, head age, head age, tenure and work place. The households with students were more likely to choose kangnam are. The households without young children had higher probability to choose new town near Seoul. Prime reason of this two results were considered the chi Id education and their better housing, Kangnam area was known to be the first consideration for residential choice regardless of work place. Low level of choice probability of kangman area for future residences however, was evidenced. Prime reason of such seemingly contradicting phenomenon is suspected for higher housing prices and limited affordability of people surveyed.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.04a
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• pp.325-329
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• 2006

In this paper, the Bayesian procedure for the multiple test of fraction nonconforming, p, is proposed. It is the procedure for checking whether the process is out of control, in control, or under the permissible level for p. The procedure is as follows: first, setting up three types of models, $M_1:p=p_0,\;M_2:pp_0$, second, computing the posterior probability of each model. and then choosing the model with the largest posterior probability as a model most fitted for the observed sample among three competitive models. Finally, the simulation study is performed to examine the proposed method.

• Korea journal of population studies
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• v.33 no.3
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• pp.1-30
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• 2010

This study examines difference in age at marriage between spouses and more importantly, investigates into the economic and social factors affecting the ratio or probability of wife-older marriages. Empirical analysis is carried out by applying both logit model and multinomial logit model to an independently pooled cross-section over 2004-2007. The data was collected mainly from the micro data service system of the Statistics Korea. Empirical results indicate that a wife-older marriage was more likely as a wife was more educated and was a larger income earner than a husband. On the other hand, a wife's educational and income level themselves had few systematic relationships with the probability of a wife-older marriage. The probability of a wife-older marriage tended to decrease(increase) when a husband's(a wife's) marriage was the second' The study calculates the average marginal effect of difference in the income level between spouses on the probability of a wife-older marriage, which is -0.007. That is, the probability of a wife-older marriage increases by 0.7% as a husband's income level is 1 million Korean Won less than a wife's. This results presents empirical evidence against widely distributed misconception on wife-older marriage in the mass media.

• Journal of the Korean Statistical Society
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• v.25 no.4
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• pp.489-497
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• 1996

Lower bounds for the full level probabilities are derived under order restrictions in weights. Discussions are made on typical isotonic cones such as linear order, simple tree order, and unimodal order cones. We also discuss applications of these results for constructing conditional likelihood ratio tests for ordered hypotheses in a contingency table. A real data set on torus mandibularis will be analyzed for illustrating the testing procedure.