• Journal of the Korean Institute of Gas
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• v.16 no.4
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• pp.44-51
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• 2012

It is more important to realize safety management, medium-large accident prevention and risk prediction as accident of industry facilities can generate enormous physical and human damage because most energy plant might handle toxic substance. Especially, atmospheric dispersion system, which is able to simulate situation, have been used for release accident of toxic substance since the accident can show different of dispersion range and velocity according to release material, storage facility and atmospheric status. However those systems have been used generally in design step of industry facility and are difficult to deal with release accident quickly. Although some researches and cases have been studied for using real-time atmospheric information, there are insufficient system for processing quickly release accident. This paper aims to develop real-time smart atmospheric dispersion system that can deal with release accident quickly by enhancing distinct characteristics and efficiency of energy plant, and select release time and area using intelligent algorithm as accident prevention type.

• Industry Promotion Research
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• v.6 no.3
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• pp.19-24
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• 2021

There should be no problem in the measurement system for scientific quality management. In this paper, we want to correctly identify the factors that can affect the measurement results during the measurement process and identify what causes them when the measurement results cause problems in terms of location and variation. Variations in the measurement system are largely described in terms of location and dispersion. Location-related attributes are accuracy, stability, and linearity while dispersion-related attributes are reproducibility and repeatability. Analyzing the factors associated with dispersion is an R&R analysis, in which the size of repeatability and reproducibility is represented by a range of differences between multiple measurements and a range of differences between measurements, and 99% of dispersion is determined. Experimental design can also be used for measurement system analysis. Proper analysis is performed only when the factors causing the fluctuation, the worker and the product, are correctly identified as random or fixed factors.

• Journal of Environmental Science International
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• v.16 no.6
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• pp.715-723
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• 2007

The air pollutant emission is mainly caused by line sources in urban area. For example, the annually totaled air pollutant emission is known to consist of about 80% of line sources in Daegu. Hence, the appropriate assessment on the air pollutants of line sources is very important for the atmospheric environmental management in urban area. In this study, we made a comparative study to evaluate suitable dispersion model for estimating the air pollution from line sources. Two air pollution dispersion models, ISCST3 and CALINE4 were the subject of this study. The results were as follows; In the assessment of air pollution model, ISCST3 was found to have 4 times higher concentration than CALINE4. In addition, actual data obtained by measurement and estimated values by CALINE4 were generally identical. The air pollution assessment based on ISC3 model produced significantly lower values than actual data. The air pollution levels estimated by ISCST3 were very low in comparison with the observational values.

• Journal of Korean Society for Quality Management
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• v.36 no.3
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• pp.1-12
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• 2008

Obtaining the accurate final importance of each customer attribute (CA) is very important in the house of quality(HOQ), because it is deployed to the quality of the final product or service through the quality function deployment(QFD). The final importance is often calculated by the multiplication of the relative importance rate and the competitive priority rate. Traditionally, the sample mean is used for estimating two rates but the dispersion is ignored. This paper proposes a new approach that incorporates statistical significance to consider the dispersion of rates in determining the final importance of CA. The approach is illustrated with a design of car door for each case of crisp and fuzzy numbers.

• The Journal of Sustainable Design and Educational Environment Research
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• v.7 no.2
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• pp.30-46
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• 2008

In this study, were prepared after statistical analysis was conducted of assessment items and marks distribution for the selection of executors of the BTL project. When tests of the degree of dispersion and degree of appropriateness for each assessment item were analyzed, it was found that the degree of dispersion among assessment points has the power of discrimination since it is highly marked in the design field and operation management field. In contrast, 'business management plan' and 'investment composition for economic quality assessment' have a low level of the power of discrimination since points given to them have smaller difference between business projects.

• Journal of Korean Society for Quality Management
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• v.25 no.4
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• pp.88-98
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• 1997

For quality improvement, it is important to reduce variations of the quality characteristic. That can be achieved by the a, pp.ication of parameter design methodology to make the performance of the quality characteristic robust over the variety of noise conditions. Taguchi has used the signal-to-noise ratios for that purpose. For the static target characteristic and the dynamic characteristic problem, we propose a reasonable generalized SN ratio and p-value plot for identifying dispersion factors. The orginal idea of the p-value plot in from the gamma-plot in Lunani, Nair & Wasserman(1995). The graphic advantage of the p-value polt for identifying dispersion factors is illustrated through constructed examples.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.721-730
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• 2021

Maritime air pollutants around port cities have gained a great deal of attention due to their direct impacts on regional air quality. This study aims to determine the geographical properties of sea/land breezes in different areas to discover overall ranges of maritime emission dispersion. The HOTMAC-RAPTAD modeling program was used to simulate regional-scale air dispersion considering non-linear and unsteady states during the general summer period for the target areas of the Yellow Sea (Incheon Port and Pyeongtaek·Dangjin Ports), archipelago region (Mokpo Port), South and East Sea (Busan and Masan Ports) and East Sea with mountainous area (Donghae·Mukho Ports). The resulting dispersion lengths of vessel emissions into the onshore regions around the target ports shed light on portal air quality management, because vessel emissions from the Incheon, Mokpo, Busan, and Donghae·Mukho ports were transported 27-31km (Western Seoul), 21-24km (Southern Muan), 20-26km (Gimhae and Yangsan), and 22-25km (Taebeak Mountains), respectively. Therefore, the results of this study provide useful data for regional air quality management and marine air pollution mitigation to improve the sustainability of port cities.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.50-58
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• 2018

Process Capability ($C_{pk}$) is a representative measure of how well the producer manages dispersion and bias for the specifications needed by the consumer. This is expressed as a ratio of 6 times the natural tolerance to the specification. As the producer manages the dispersion small, the capacity index becomes higher. And it is classified into 5 grades according to the degree of management. It is a measure of the quality of processes used in most industrial fields. However, $C_{pk}$ is calculated by only reflecting the mean and dispersion of the process, there is a disadvantage that it can not give information about the economic loss caused by the inconsistency of the process with the target value. Overcoming these drawbacks, process capability indexes reflecting various types of loss functions such as $C_{pm}$, $C^+_{pm}$ and $C_{pl}$ have been developed. However, all of these previous studies have applied the limit to the consumer specification, which is based on the traditional and passive quality perception that the quality characteristic should exist within the limits of the consumer specification. In this study, we will develop 'Customer Satisfaction Quality Indicator (CSQI)' which is a quantitative indicator that can be fully evaluated when the manufacturer's specification limit, which is an aggressive quality strategy, is applied. This is expected to be useful decision information for both producers and consumers.

• International Journal of Highway Engineering
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• v.15 no.4
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• pp.167-175
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• 2013

PURPOSES : The objective of this study is to investigate the capability of the combined model of traffic simulation, emission and air dispersion models on the impact analysis of air quality of mobile sources such as vehicles. METHODS : The improvement of the quality of life brings about the increasing interest of the public environment. Many endeavors including the travel demand management, the application of the state-of-the-art ITS technologies, the promotion of eco-friendly vehicles have been tried in transportation area to reduce the modal emissions. Especially, it is expected that the increasing number of eco-friendly vehicles in the road network would be able to reduce the pipe-tail emissions tremendously. From this perspective, we have performed a study on the impact analysis of the popularization of the eco-friendly vehicle in the place of the fossil fuel energy powered vehicles on the surrounding air quality using the combined framework of microscopic traffic simulation, emission and air dispersion model. RESULTS : The combined model successfully captured the effect of moving to the eco-friendly vehicles on the air quality, and the results showed that the increasing usage of eco-friendly vehicles can improve the surrounding air quality tremendously and that the air dispersion model plays a crucial role in the investigation of the air quality change around the main corridor. CONCLUSIONS : This study demonstrated the capability of the combined model showing the spatio-tempral change of emission concentration.

• Particle and aerosol research
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• v.17 no.3
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• pp.55-69
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• 2021

Chungnam region accounts for the largest SO_X (22.8%) emission with the second-largest NO_X (10.8%) emission in Korea due to the integration of many large industrial sources including a steel mill, coal-fired power plants, and petrochemical complex. Air pollutants emitted by large industrial sources can cause harmful problems to humans and the environment. Thus, it is necessary to understand dispersion patterns of air pollutants from large industrial sources in Chungnam to characterize atmospheric contamination in Chungnam and the surrounding area. In this study, seasonal atmospheric dispersion characteristics for SO_X, NO_X, and PM2.5 from ten major point sources in Chungnam were evaluated using HYSPLIT 4 model, and their contributions to SO₂, NO₂ concentrations in the regions near the source areas were estimated. The predictions of the HYSPLIT 4 model show a seasonal different dispersion pattern, in which air pollutants were dispersed toward the southeast in winter while, northeast in summer. In summer, due to weaker wind speed, air pollutants concentrations were higher than in winter, and they were dispersed to the metropolitan area. The local emissions of air pollutants in Taean area had a greater influence on the ambient SO₂ and NO₂ concentrations at Taean, whereas SO_X and NO_X emissions from large sources located at Seosan showed relatevely little effect on the ambient ambient SO₂ and NO₂ concentrations at Seosan.