• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.95-104
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• 2018

Using network betweenness centrality we attempt to analyze the characteristics of Seoul metropolitan subway lines. Betweenness centrality highlights the importance of a node as a transfer point between any pairs of nodes. This 'transfer' characteristic is obviously of paramount importance in transit systems. For betweenness centrality, both traditional betweenness centrality measure and weighted betweenness centrality measure which uses monthly passenger flow amount between two stations are used. By comparing traditional and weighted betweenness centrality measures of lines characteristics of passenger flow can be identified. We also investigated factors which affect betweenness centrality. It is the number of passenger who get on or get off that significantly affects betweenness centrality measures. Through correlation analysis of the number of passenger and betweenness centrality, it is found out that Seoul metropolitan subway system is well designed in terms of regional distribution of population. Four measures are proposed which represent the passenger flow characteristics. It is shown they do not follow Power-law distribution, which means passenger flow is relatively evenly distributed among stations. It has been shown that the passenger flow characteristics of subway networks in other foreign cities such as Beijing, Boston and San Franciso do follow power-law distribution, that is, pretty much biased passenger flow traffic characteristics. In this study we have also tried to answer why passenger traffic flow of Seoul metropolitan subway network is more homogeneous compared to that of Beijing.

• Journal of Environmental Health Sciences
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• v.36 no.5
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• pp.360-372
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• 2010

Concentrations of ambient air particles such as total suspended particulates (TSP), particulate matter $(PM)_{10}$, and $PM_{2.5}$, were monitored simultaneously from May to June, 2007, at four locations at Alashan and Beijing in China, and Seoul and Gosan in South Korea. These monitoring sites are in the pathway of Asian dust (AD) storms traveling from China to the Korean peninsula. An AD event was observed in the Korean peninsula on May 25-26. During the sampling period, the average concentrations of TSP and PM10 were each higher than $150\;{\mu}g/m^3$ in Alashan and Beijing, but not in Seoul and Gosan. The concentration of TSP in Alashan (where the dust storm originated) on the day of the AD event reached $1824.7\;{\mu}g/m^3$, this being the highest concentration of air particles observed during the sampling period. The level was decreased to 15% of this ($274.7\;{\mu}g/m^3$) in Seoul and to 8.7% ($159.0\;{\mu}g/m^3$) in Gosan when the AD was observed two days later in Korea. Gosan, a representative background site in East Asia, displayed the lowest concentration of particles, with this maximal TSP concentration of $159\;{\mu}g/m^3$. Inorganic element contents in the air particles were also measured, and the concentrations in the four different regions compared. Concentrations of anthropogenically-enriched heavy metals in $PM_{10}$ and $PM_{2.5}$, such as lead, arsenic, cadmium, and mercury, were higher in the metropolitan cities of Beijing and Seoul compared to non-industrialized regions of Alashan and Gosan. However, the concentrations of inorganic soil elements including iron, magnesium, aluminum sodium, and manganese, were higher in Alashan compared to those in other sampling sites.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.10a
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• pp.324-325
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• 2008

• Communications for Statistical Applications and Methods
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• v.25 no.2
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• pp.199-215
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• 2018

Interest in $PM_{10}$ concentrations have increased greatly in Korea due to recent increases in air pollution levels. Therefore, we consider a forecasting model for next day $PM_{10}$ concentration based on the principal elements of air pollution, weather information and Beijing $PM_{2.5}$. If we can forecast the next day $PM_{10}$ concentration level accurately, we believe that this forecasting can be useful for policy makers and public. This paper is intended to help forecast a daily mean $PM_{10}$, a daily max $PM_{10}$ and four stages of $PM_{10}$ provided by the Ministry of Environment using various data mining techniques. We use seven models to forecast the daily $PM_{10}$, which include five regression models (linear regression, Randomforest, gradient boosting, support vector machine, neural network), and two time series models (ARIMA, ARFIMA). As a result, the linear regression model performs the best in the $PM_{10}$ concentration forecast and the linear regression and Randomforest model performs the best in the $PM_{10}$ class forecast. The results also indicate that the $PM_{10}$ in Seoul is influenced by Beijing $PM_{2.5}$ and air pollution from power stations in the west coast.

• Journal of Environmental Science International
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• v.18 no.6
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• pp.655-665
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• 2009

This study aims to identify the impacts of air quality in the Korean Peninsula according to the China's environmental policies in preparation of the Beijing 2008 Olympic Games. The measurement of emission variations in China, aircraft measurement, and modelling were carried out. The reduction measures in Beijing, China and its emission changes resulted in $30{\sim}65%$ in decrease out of the total emissions within the Beijing region, whereas when it comes to the whole nation of China, the reduction rate was about $4{\sim}9%$. Comparing the concentration of the air pollutants in Seoul and Ganghwa in August 2008 during around the period of Beijing Olympic Games with one in $2004{\sim}2007$ showed that the $SO_2$ concentrations in the past was above 5ppb, while the concentration in the 2008 olympic period was 4ppb and below. The NOx at the Seokmori site in Ganghwa tended to be lower in concentration in 2008 than in between $2004{\sim}2007$. As for $O_3$ and $PM_{2.5}$, the concentration tended to be rather low since August 11. The air current track that showed during the period of aircraft measurement presented to be flowed into Korea through the Northeast part of China and the coast of Bohai Bay, while the concentrations of $SO_2$. NOx, and $O_3$ over the west sea on August 20 and 24 were 0.54 (0.28ppb), 0.86 (1.84ppb), and 54.0 (41.5ppb) respectively, similar or lower than the ones measured in the past in the similar current patterns. The modelling result showed similar patterns to the data of aircraft measurement, in particular in $SO_2$. Overall, the reduction measures in Beijing, China affected directly and indirectly the air quality in the Korean peninsular, but the impact was not significant as it was momentary and limited to the intended area.

• Journal of the Korean Regional Science Association
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• v.15 no.2
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• pp.117-130
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• 1999

Northeast Asia's burgeoning mage- cities have an extraordinarily economic vitality. While national statistics disguies how economic activity is concentrated, much of the region's robust growth of recent decades has centered around large cities, such as Tokyo, Seoul, Beijing, Shaghia, Hongkong. These cities are also at the heart of the Northeast Asia's emerging reional economy. This paper aims to compare the advantages and disad- vantages of these selected Northeast Asia cities in various categories of urban competitiveness and cooperation. Above all, the paper compares the individual cities with one another, and analyzes relations and linkages among them. Then, strengths that can be reinforced and weakness that can be overcome are identified for each city. Finally, an urban development strategy for Seoul in the context development strategy for Seoul in the context of Northeast Asian cities is provided : I) Seoul should strive to be an effective regional capital of Northeast Asia ; ii) Seoul should be a focal point for the intermingling of Chinese, Japanese and Western cultures.

• Journal of Korean Society for Quality Management
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• v.22 no.3
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• pp.142-151
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• 1994

In a hospital, there are many clinical departments. In general, the hospital management often uses the index of cure rate (i.e. the rate of patients recovered by the cure of this hospital) to evaluate the medical quality of each clinical department. But, since the cure rate varies significantly with the rate of patient with severe disease, the evaluation by cure rate is unreasonable and incomplete. This paper proposes a new evaluation method called the cause-selecting evaluation method proposed by Prof. Gongxu Zhang (1990). Besides, this method can also be used to diagnose the abnormality of cure rate. The practical case studies check with the theory very well.

• Particle and aerosol research
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• v.4 no.1
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• pp.1-7
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• 2008

Temporal trends of the PM10 and PM2.5 mass concentrations, and the concentrations of chemical species (sulfate, nitrate, ammonium, OC, and EC) in PM2.5 at Seoul are compared with the reported results from other mega cities in the world. The mass concentrations of PM10 and PM2.5 at Seoul show decreasing trend. However, the concentration levels are still higher than other cities except Beijing. The sulfate concentration at Seoul has decreased while those of nitrate and ammonium have increased. The concentrations of OC and EC show no apparent trend.

• International Area Studies Review
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• v.13 no.3
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• pp.613-636
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• 2009

This paper examines the performance of assessing sponsors and non-sponsors recall and recognition at the 2008 Beijing Olympic Games perceived by Korean and Chinese university students. Using a sample of 1,573 respondents, a survey was administered in Seoul and Beijing before and after Games to compare the recall and recognition that changed between two periods. The findings reveal that the effectiveness of the 2008 Beijing Olympic sponsorship has was lower than we expected. Results were founded that while Samsung(mobile), Coca-cola, McDonald's, and Visa achieved the desired sponsorship marketing effectiveness in Korea. On the other hand, non-sponsors of Nike, Dell, AIG, Samsung(computer) and Hyundai led to obtain the benefit and resulted in increasing consumer confusion as to who is a sponsor. In China, Samsung, Coca-cola, Lenovo, Volkswagen, Visa, and PICC achieved the desired sponsorship marketing effectiveness. On the other hand, Lining, Nokia, KFC, China Merchants Bank had some impact on the effectiveness of a rival brand from an official sponsor's product category. The paper concludes by considering some issues for sponsorship marketers.

• 대한예방의학회:학술대회논문집
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• 1999.10a
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• pp.242-243
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• 1999