• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.4
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• pp.118-129
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• 2016

Many epidemiological studies, relying on administrative air pollution monitoring data, have reported the association between particulate matter ($PM_{10}$) air pollution and human health. These monitoring data were collected at a limited number of fixed sites, whereas government-generated health data are aggregated at the area level. To link these two data types for assessing health effects, it is necessary to estimate area-level concentrations of $PM_{10}$. In this study, we estimated district (Gu)-level $PM_{10}$ concentrations using a previously developed pointwise exposure prediction model for $PM_{10}$ and three types of point locations in Seoul, Korea. These points included 16,230 centroids of the largest census output residential areas, 422 community service centers, and 610 centroids on the 1km grid. After creating three types of points, we predicted $PM_{10}$ annual average concentrations at all locations and calculated Gu averages of predicted $PM_{10}$ concentrations as representative Gu-estimates. Then, we compared estimates to each other and to measurements. Prediction-based Gu-level estimates showed higher correlations with measurement-based estimates as prediction locations became more population representative ($R^2=0.06-0.59$). Among the three estimates, grid-based estimates gave lowest correlations compared to the other two(0.35-0.47). This study provides an approach for estimating area-level air pollution concentrations and assesses air pollution health effects using national-scale administrative health data.

• Journal of Digital Convergence
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• v.13 no.8
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• pp.419-429
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• 2015

We investigate how the regional prevalence of hyperlipidemia is affected by health-related and socioeconomic factors with a special emphasis on geographic variations. We focus on the likelihood of hyperlipidemia as function of various region-specific attributes. We analysis a data set at the level of 249 small administrative districts collected from 2012 Korean Community Health Survey by Korea Centers for Disease Control and Prevention. To estimate, we use several methods including correlation analysis, multiple regression and decision tree model. We find that the average prevalence of hyperlipidemia in 249 small districts is 9.6% and its coefficient of variation is 28.3%. Prevalence of hyperlipidemia in continental and capital regions is higher than in southeast coastal regions. Further findings using decision tree model suggest that variations of hyperlipidemia prevalence between regions is more likely to be associated with rate of employee, level of stress, prevalence of hypertension, angina pectoris, and osteoarthritis in their regions.

• Journal of the Korean Data and Information Science Society
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• v.26 no.1
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• pp.1-10
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• 2015

This paper offers some long term perspective on what has been happening to some baseball statistics for Korean professional baseball. The data used are league summaries by year over the period 1982-2013. For the baseball statistics, statistically significant positive correlations (p < 0.01) were found for doubles (2B), runs batted in (RBI), bases on balls (BB), strike outs (SO), grounded into double play (GIDP), hit by pitch (HBP), on base percentage (OBP), OPS, earned run average (ERA), wild pitches (WP) and walks plus hits divided by innings pitched (WHIP) increased with year. There was a statistically significant decreasing trend in the correlations for triples (3B), caught stealing (CS), errors (E), completed games (CG), shutouts (SHO) and balks (BK) with year (trend p < 0.01). The ARIMA model of Box-Jenkins is applied to find a model to forecast future baseball measures. Univariate time series results suggest that simple lag-1 models fit some baseball measures quite well. In conclusion, the single most important change in Korean professional baseball is the overall incidence of completed games (CG) downward. Also the decrease of strike outs (SO) is very remarkable.

• Journal of the Korean Data and Information Science Society
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• v.26 no.3
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• pp.661-668
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• 2015

Them traffic accidents have been increased every year due to increasing of vehicles numbers as well as the gravitation of the population. The carelessness of drivers, many road weather factors have a great influence on the traffic accidents. Especially, the number of traffic accident is governed by precipitation, visibility, humidity, cloud amounts and temperature. The purpose of this paper is to analyse the effect of road weather factors on traffic accident. We use the data of traffic accident, AWS weather factors (precipitation, existence of rainfall, temperature, wind speed), time zone and day of the week in 2013. We did statistical analysis using logistic regression analysis and decision tree analysis. These prediction models may be used to predict the traffic accident according to the weather condition.

• KDI Journal of Economic Policy
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• v.37 no.sup
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• pp.33-63
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• 2015

This paper attempts to investigate the Korean households' inflation expectations with particular attention to information rigidity. For this purpose, we derive an empirical model from a sticky information model $\acute{a}$ la Mankiw and Reis (2002) and estimate it. In addition, it is also examined whether the expectation formation is state-dependent on macroeconomic conditions. The main findings of this paper are as follows. First, it turns out that the information rigidity in Korean households' inflation expectations is very high. In a month, most of the households simply keep their inflation expectations the same as before instead of updating them based on newly arrived information. Furthermore, when updating their expectations, the households tend to rely on the backward-looking information such as actual inflation rates in the past rather than on the forward-looking forecasts by experts. Second, it is found that the expectation formation is varying as inflation rate changes. Specifically, when the inflation is high, the sensitivity of the households' inflation expectations to actual inflation increases and the gap between inflation expectations and actual inflation shrinks. It implies that Korean households update their expectations more frequently when the inflation matters than not.

• Journal of the Economic Geographical Society of Korea
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• v.11 no.2
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• pp.192-202
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• 2008

Typical activity-based travel analysis has been focused on passenger travel using household survey data. The current research focuses on freight transport using one-day travel survey data. Passenger travel can be seen as the outcome of traveller's subjective decision-making, whereas freight transport is the outcome of shipper or transport company's optimized scheduling. The research conducts an activity-based analysis of freight-vehicle trip chains. In particular, the research focuses on the difference in travel pattern between shipper-oriented private vehicle and transport company-oriented business vehicle. The research analyzed the travel diary of freight vehicles collected as part of the third national logistic survey in 2005. The diary is freight driver's one-day travel record including the information of loading capacity, item transported, destination, arrival time, etc. The analysis results show the difference between private and business vehicles in the travel pattern regarding the sequences of destination, destination type and item transported and the multi-dimensional information of the three sequences.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• v.21 no.1
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• pp.17-30
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• 1993

The basic processes responsible for the generation of oceanic fronts were reviewed. In particular the process of a shelf sea front produced by tidal stirring was identified from the one dimensional model of the water column in the coastal area, which incorporates the microscale process for the formation of a tidal front. Also a new criterion to predict its location was suggested. The time evolutions of the distributions of density and turbulent kinetic energy calculated from the model show that the criterion for the formation of a thermocline can be predicted as $R{\delta}^4$~ constant for large $\delta$ ($\delta$＞0.5), but the dependence on $\delta$ decreases as $\delta$ goes to O, where $R=H^4Q/{K_b}^3$,{\;}{\delta}=1-Do/H$, Q is the buoyancy flux at the surface, $K_b$ is the eddy diffusivity maintained at the bottom and Do is the depth of a thermocline in the absence of bottom mixing. The depth of a thermocline was found to decrease as the bottom mixing increases for a given value of Do. The results were interpreted in comparison with the previous studies.

• Journal of the Korea Society of Computer and Information
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• v.20 no.2
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• pp.187-195
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• 2015

In this paper, we examined the effect of positive affect and negative affect on the life satisfaction in the workplace. Also, this study focused on an empirical test of the role of work self-efficacy and work meaningfulness in the subjective well-being of office worker. To achieve this purpose, we suggested a research model consisting of factors such as work self-efficacy, work meaningfulness, positive affect, negative affect, life satisfaction. Data was collected using the survey method, and analyzed using structural equation model. According to PLS analysis, first, lower negative affect was associated with higher life satisfaction. Secondly, work meaningfulness was a very important predictor for the subjective well-being of office worker.

• Journal of Korean Society of Transportation
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• v.21 no.4
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• pp.47-56
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• 2003

There are no specific criteria deciding what type of crosswalk installs although 4 typed crosswalks at signalized intersections classify according to number of stop line, spacing from the border of intersections and existence of traffic islands or not. Accidents involving pedestrians at signalized intersections are classified by type of crosswalks by traffic volume, pedestrian volume at crosswalk, intersection geometry and phase in view of pedestrians' safety at 50 intersections in Gwangju. The Multiple regression models are applied to express the pedestrian accident rate. In addition, process deciding what type of crosswalk installs which includes accident rate involved pedestrian is changed into number of accident is represented to reduce number of accidents. This paper presents what type of crosswalk installs in order to reduce pedestrian involved accidents at new or existing crosswalk.

• Journal of Korea Water Resources Association
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• v.35 no.3
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• pp.295-306
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• 2002

The modified TOPMODEL of two storage systems has been integrated to the generalized assumptions of decreasing hydraulic conductivity to vertical direction. Three different recharge functions were introduced to explore the impact of the macropore flow to vortical direction, the storage at the surface zone and the relative storage deficit of the soil matrix. Combinations of these approaches provide 30 type of the model structure for the hillslope hydrology. Developed models have been applied to several hydrologic events at the Sulmachun watershed. The performance evaluation with the Monte carlo simulation suggests that the exponential function of transmissivity reduction should be appropriate form for the physically -based hydrologic simulation on the Sulmachun watershed. It has been shown that the recharge function of macropore flow contributes to improve the predictability of the generalized version of modified TOPMODEL.