• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.11 no.2
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• pp.126-134
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• 2001

Statistical approaches for analysis of data from the limited number of samples in ship building industry(SBI) collected by an industrial hygienist for checking compliance to an occupational standard were considered. Sampling for compliance usually has been guided by judgment selection, rather than true randomness, resulting in the creation of compliance samples which approximate a censored sample from the upper tail of the exposure distribution. Similar exposure groups(SEGs) including welding and painting process were established to assess representative values in each groups after reviewing the whole production line in SBI. For the convenient statistical approaches, the code has assigned to each SEGs. The descriptive statistics and probability plotting were used to yield the representative values in each SEGs. In the first step, SEGs of 558 were established from 5 ship building companies. The 38 SEGs showed the uncertainty are divided into each 5 companies and assessed the representative values again. The 44 SEGs in each companies was not showed the normal and lognormal distribution was analyzed each data. And also, recommendation was suggested to resolve the uncertainty in each groups.

• The Journal of the Korea Contents Association
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• v.13 no.3
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• pp.435-443
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• 2013

While rural highways carry on lower traffic volumes, the deviations of running speeds between vehicles appear to be higher on rural highways than urban highways. The speed characteristic of rural highways is adding to pedestrian-related accidents which occur on a crosswalk with poor sight distance due to the limits of car headlights and lighting. Specially, the aged was mostly occupied in nighttime-related accidents on crosswalks, and pedestrians crossing on the far side of approaching vehicles appear to have the probability of fatality higher than the near side. An alternative is needed to resolve the compounded accidents, and then this study is to establish a new approach to an optimum lighting environment on a crosswalk to improve pedestrian safety. This study was conducted by a survey and a field study on the lighting of existing crosswalks. The field study shows that the existing lighting has the problem of wasting energy and impeding walking due to glare. The survey shows that nighttime sight distance on a crosswalk is required to improve and that road users prefer to be brighter pedestrian waiting space together with the crosswalk. Thus, a lighting environment that is not too bright and illuminates the crosswalk and the pedestrian waiting space is needed to implement.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.2
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• pp.217-225
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• 2010

Most of the steel bridges in Korea are being currently designed by the allowable stress design method that uses the conventional deterministic factors of safety. However the limit state design based on the concept of probability, statistics and reliability engineering is becoming very popular as a global standard deign method, leading the rational and economic bridge design. As part of the fundamental research to establish the load and resistance factor design(LRFD) of steel bridges considering domestic environmental conditions and regional characteristics, an experimental design is conducted by applying AASHTO-LRFD specification especially to a steel closed-box girder, which occupies relatively a large portion of steel bridges in Korea. Throughout the experimental design according to various sectional changes, some of the issues to be considered in the LRFD design of a composite steel closed-box girder bridge are examined. In this process, an Excel-based design verification program is developed for easy computation and prevention of errors. Quantitative reliability levels of the bridge sections designed by LRFD are also estimated using a reliability analysis method, and compared with the target reliability indexes applied in the LRFD design to verify the validity of the procedure and methodology used in this study.

• Journal of Advanced Navigation Technology
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• v.10 no.4
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• pp.371-376
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• 2006

The initial radius of sphere decoder has great effect on the bit error rate performance and computational complexity. Until now, it has been determined either by considering the statistical property of channel or by using of MMSE solution. The initial radius obtained by using statistical property of channel includes the lattice point corresponding to the transmit signal vector with very high probability. The method using MMSE solution first calculates out the MMSE solution of the received signal, then maps the hard decision of this solution into the received signal space, and finally the distance between the mapped point and the received signal is selected as the initial radius of the sphere decoding. In this paper, we derive a simple equation for initial radius selection which uses statistical property of channel and compare it with the method using MMSE solution. To compare two methods we define new metric 'Tightness'. Through the simulation, we observe that in low and moderate SNR region, the method using MMSE solution provides more complexity reduction for decoding while in high SNR region, the method using channel statistics is better.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.4
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• pp.313-319
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• 2007

Long term wave climate of both extreme and operational wave height is essential for planning and designing coastal structures. Since the availability of the field wave data for the waters around Korean peninsula is limited to provide a reliable wave statistics, the wave climate information has been generated by means of long-term wave hindcasting using available meteorological data. In this paper, a set of deep water wave data obtained from KORDI(2003) were analyzed for extreme wave heights. These wave data at 67 stations off the Korean coast from 1979 to 1998 were arranged in the 16 directions. The probability distributions considered in this research were the FT-I and Weibull distribution. For each of these distributions, the method proposed by Goda(2004) was applied to estimate the parameters. For judgment of best fitting, MIR criterion proposed by Goda and Gobune(1990) was used. FT-I distribution which best fits to the 886 data, while Weibull(k=0.75) 81 data, Weibull(k=1.00) 105 data.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.1
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• pp.81-102
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• 2010

The purpose of this study was to analyze the content and design of the seven math camp programs for students of the education centers for the elementary gifted students. The analysis focused on the goals, content, and evaluations utilized in the math camp programs. The results of the study were as follows. First, there was no big difference between the goals set for each camp, and they mainly focused on the goals in affective domain. Second, the content of math camp programs was focused on enrichment rather than acceleration. Most of the programs were focused on geometry, whereas fewer programs were focused on measurement, probability and statistics. Based on the Analysis, we found that only nine out of 27 programs applied level-wised or individual exercise programs. Third, all centers for the mathematically gifted carried out evaluations of their math camp programs. However, a specific evaluation plan was not established for the math camp program plans. We suggested the direction of math camp programs as follows. First, the goals should reflect on the intended outcomes of the math camp programs. Also, the goals of math camp programs need to be distinctive from general education goals. Second, the programs should contain harmonious contents with enrichment and acceleration and must include various reactions and task commitment. The math camp programs need to include references and an appropriate information for the gifted students to encourage self-directed learning. Third, a more specific evaluation plan for math camp programs needs to be developed for effective education for the gifted students.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.2
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• pp.123-133
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• 2010

A statistical evaluation methodology was developed to determine the compliance of candidate waste stream with clearance criteria based upon distribution of radionuclide in a waste stream at a certain confidence level. For the cases where any information on the radionuclide distribution is not available, the relation between arithmetic mean of radioactivity concentration and its acceptable maximum standard deviation was demonstrated by applying widely-known Markov Inequality and One-side Chebyshev Inequality. The relations between arithmetic mean and its acceptable maximum standard deviation were newly derived for normally or lognormally distributed radionuclide in a waste stream, using probability density function, cumulative density function, and other statistical relations. The evaluation methodology was tested for a representative case at 95% of confidence level and 100 Bq/g of clearance level of radioactivity concentration, and then the acceptable range of standard deviation at a given arithmetic mean was quantitatively shown and compared, by varying the type of radionuclide distribution. Furthermore, it was statistically demonstrated that the allowable range of clearance can be expanded, even at the same confidence level, if information on the radionuclide distribution is available.

• The Korean Journal of Applied Statistics
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• v.21 no.1
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• pp.19-33
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• 2008

Linear regression method, proposed by Haseman and Elston(1972), for detecting linkage to a quantitative trait of sib pairs is a linkage testing method for a single locus and a single trait. However, multivariate methods for detecting linkage are needed, when information from each of several traits that are affected by the same major gene are available on each individual. Amos et al. (1990) extended the regression method of Haseman and Elston(1972) to incorporate observations of two or more traits by estimating the principal component linear function that results in the strongest correlation between the squared pair differences in the trait measurements and identity by descent at a marker locus. But, it is impossible to control the probability of type I errors with this method at present, since the exact distribution of the statistic that they use is yet unknown. In this paper, we propose a multivariate nonparametric trend test for detecting linkage to multiple traits. We compared with a simulation study the efficiencies of multivariate nonparametric trend test with those of the method developed by Amos et al. (1990) for quantitative traits data. For multivariate nonparametric trend test, the results of the simulation study reveal that the Type I error rates are close to the predetermined significance levels, and have in general high powers.

• Journal of Digital Convergence
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• v.12 no.7
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• pp.327-336
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• 2014

This study aims to identify factors to affect regular utilization status of medical care in cardio-cerebrovascular patients. The research selected 770 cardio-cerebrovascular patients among surveyees from the Korea Health Panel 2010. We analyzed states of medical care utilization using descriptive statistics. Logistic regression analysis was used to examine the main factors associated with regular utilization status of medical care in cardio-cerebrovascular patients. In result, the significant factors associated with regular utilization status of medical care in cardio-cerebrovascular patients were age, education level, household income level. CCI, presence or absence of high risk drinking, and presence or absence of obesity. There's a high probability that patients aged between 60 and 69, equal to and higher than those of high school graduate in education level, upper middle class in household income, the higher CCI, absence of high risk drinking, presence of obesity utilize medical care services more regularly. Therefore, it is necessary to develop effective program and individualized approach for patients using lesser periodical medical care and patients with high risk drinking problem. In the future, these findings can be used an important data for healthcare policy and assessment.

• Journal of the Korean Geographical Society
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• v.52 no.1
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• pp.123-141
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• 2017

This study predicted urban green spaces for 2020 based on two scenarios keeping or freeing the green-belt in the Daegu metropolitan city using a hybrid Cellular Automata(CA)-Markov model and analyzed the spatial dynamics of urban green spaces between 2009 and 2020 using a land cover change detection technique and spatial metrics. Markov chain analysis was employed to derive the transition probability for projecting land cover change into the future for 2020 based on two land cover maps in 1998 and 2009 provided by the Ministry of Environment. Multi-criteria evaluation(MCE) was adopted to develop seven suitability maps which were empirically derived in relation to the six restriction factors underlying the land cover change between the years 1998 and 2009. A hybrid CA-Markov model was then implemented to predict the land cover change over an 11 year period to 2020 based on two scenarios keeping or freeing the green-belt. The projected land cover for 2009 was cross-validated with the actual land cover in 2009 using Kappa statistics. Results show that urban green spaces will be remarkably fragmented in the suburban areas such as Dalseong-gun, Seongseo, Ansim and Chilgok in the year 2020 if the Daegu metropolitan city keeps its urbanization at current pace and in case of keeping the green-belt. In case of freeing the green-belt, urban green spaces will be fragmented on the fringes of the green-belt. It is thus required to monitor urban green spaces systematically considering the spatial change patterns identified by this study for sustainably managing them in the Daegu metropolitan city in the near future.