• Journal of Korean Society of Transportation
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• 제25권3호
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• pp.19-28
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• 2007

Korea's national highways, which emphasize a high level of mobility, serve primarily intercity travel and are used as a detour for freeways. However. at the present. the highways do not have consistent geometric features or other characteristics: for example. some highways have full access control and others have uncontrolled access. Generally, geometric and traffic conditions affect Pronouncedly travel speeds in the highway sections. This study focused on the effect of signalized intersection relative factors on the speeds: signalized intersection densities, signal phases, and volume levels. The study shows that signalized intersection density was the strongest variable affecting the travel speeds: the speeds held fairly constant over intersection densities below 0.3 intersections/km, decreased sharply through intersection density of 0.7 intersections/km. and appeared constant at the lowest level over intersection densities above 0.7 intersections/km. The results also indicate that the effect of signal and traffic volume levels on the speeds was similar to that of the signalized intersection density.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• 제16권5호
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• pp.85-95
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• 2017

This study aims to identify the throw distance in terms of truck weight, bumper height, and speed in a truck and pedestrian collision, and to propose a model for throw distance estimates. For this purpose, a simulation analysis is performed using the PC-crash program with the following experiment conditions: Truck weight of 5t, 15t, and 25t, Bumper height from 0.3m to 0.6m by 0.1m, and speed from 10km/h to 100km/h by 10 km/h. Experimental results show that the truck speed and bumper height are found to be significant factors for pedestrian throw distance, but truck weight is not a significant factor. Also, a regression model is developed for pedestrian throw distance estimate from the multiple regression analysis. The adjusted $R^2$ value of the model is 93.3%, which is very good explanatory power.

• The Korean Journal of Emergency Medical Services
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• 제21권2호
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• pp.51-61
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• 2017

Purpose: This study measured return of spontaneous circulation (ROSC) in relation to dispatch distance in patients with out-of-hospital cardiac arrest. Methods: Of 2,347 out-of-hospital cardiac arrest patients transported by emergency medical technicians in J Province between January 1 and December 31, 2015, those under age 18, those with reserved resuscitation, and those with traumatic cardiac arrest, leaving 855 patients in the study sample. ROSC was compared between those with dispatch distance ${\leq}4km$ (short dispatch distance, 465 patients) and those with dispatch distance >4 km (long dispatch distance, 390 patients). Results: The mean was 2.17 km in the short dispatch group and 9.87 km in the long dispatch group (p=.000). Mean distance from was 6.49 km and 13.39 km in the two groups, respectively (p=.000). ROSC differed significantly between the short and long dispatch distance groups (7.1% for short dispatch distance, 3.6% for long dispatch distance, p=.025). The length of time from to cardiopulmonary resuscitation also differed significantly between the short and long dispatch distance groups (8.77 minutes and 14.63 minutes, respectively, p=.000). Conclusion: ROSC was lower in areas of long dispatch distance compared to those of short dispatch distance. We expect this was most likely due to differences in response time by age and dispatch distance to the scene of cardiac arrest. However, no significant differences were found between the groups in the factors affecting ROSC.

• Journal of Astronomy and Space Sciences
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• 제20권4호
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• pp.269-282
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• 2003

We examined the hypothesis that the crater formation rate exhibits periodicity, employing data sets of Grieve (1991), Moon et al. (2001), and the Earth Impact Database(2002; DB02). DB02 is known to supercede previous compilations in terms of its accuracy and precision of the ages; it is the first time that this database has been used for periodicity analysis. For data sets comprising impact structures with $D{\geq}5km$(and also those with $D{\geq}20km$), there is no convincing evidence for periodicities in the crater ages, according to our Fourier analysis. However, we detected two peaks at 16.1Myr and 34.7Myr for craters with $D{\geq}30km$; we confirm that the age distribution of impact craters with $D{\geq}45km$ has dominant power at 16.1Myr. Thus, we may conjecture a probable periodic shower of Earth impactors with sizes $d{\geq}1.5km$. In addition, we found that the selection of data sets, the lower limits on the ages and diameters of impact craters, as well as the accuracy and precision of the ages, all constitute crucial factors in reconstructing the impact cratering history of the Earth.

• Journal of Korean Society of Forest Science
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• 제84권3호
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• pp.319-332
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• 1995

This research was carried out to investigate the influences of forest road characteristics and rainfalls on the amount of erosion on the newly - constructed forest road in the Research Forests of Seoul National University located in Mt. Backwoon - san, Kwangyang. Amount of soil erosion on the newly - constructed forest road was measured for 2 years since the forest road construction. Using the stepwise multiple regression method, amount of soil erosion from cut - slopes, fill - slopes, road surfaces, and side - ditches were seperately expressed as a function of statistically significant road design and rainfall factors, and multiple regression models to estimate the amount of soil erosion were significant to explain the variance in erosion by each structures. According to results of this study, amount of erosion from the newly - constructed forest road was estimated as much as 668.51m/km for 2 years. Out of total amount of soil erosion, 21.9%(144.27m/km) from cut - slopes, 39.8%(261.89m/km) from fill - slopes, 8.1%(53.33m/km) from road surfaces, and 30.2%(199.02m/km) from side - ditches were occurred.

• Journal of Wetlands Research
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• 제13권1호
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• pp.105-116
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• 2011

Changes in climate have largely increased concentrated heavy rainfall, which in turn is causing enormous damages to humans and properties. Therefore, the exact relationship and the spatial variability analysis of hydrometeorological elements and characteristic factors is critical elements to reduce the uncertainty in rainfall -runoff model. In this study, radar rainfall grid resolution and grid resolution depending on the topographic factor in rainfall - runoff models were how to respond. In this study, semi-distribution of rainfall-runoff model using the model ModClark of Inje, Gangwon Naerin watershed was used as Gwangdeok RADAR data. The completed ModClark model was calibrated for use DEM of cell size of 30m, 150m, 250m, 350m was chosen for the application, and runoff simulated by the RADAR rainfall data of 500m, 1km, 2km, 5km, 10km from 14 to 17 on July, 2006. According to the resolution of each grid, in order to compare simulation results, the runoff hydrograph has been made and the runoff has also been simulated. As a result, it was highly runoff simulation if the cell size is DEM 30m~150m, RADAR rainfall 500m~2km for peak flow and runoff volume. In the statistical analysis results, if every DEM cell size are 500m and if RADAR rainfall cell size is 30m, relevance of model was higher. Result of sensitivity assessment, high index DEM give effect to result of distributed model. Recently, rainfall -runoff analysis is used lumped model to distributed model. So, this study is expected to make use of the efficiently decision criteria for configurated models.

• Korean Journal of Environment and Ecology
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• 제38권1호
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• pp.48-54
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• 2024

This study conducted a survey from April 2021 to December 2022 to investigate habitat factors affecting bird diversity in the region between Cheonwangbong Peak and Aghwibong in Baekdudaegan protected area, South Korea. Since the region has a spatial scale of 736.4 km² and is an area where a wide variety of habitats are mixed, we selected 20 survey areas of 3 km x 3 km by analysis of habitat homogeneity. As a result of analyzing the relationship between habitat environment and bird diversity in the survey area, it was found that the diversity of bird communities was directly or indirectly related to the diversity of terrestrial insects, slope, average habitat area, mean size of patches, elevation, and forest type, and distance from agricultural land. The slope of habitat, forest type, and distance from agricultural land affect the occurrence of food sources directly and indirectly, and the average area of habitats and forest type is closely related to the structural diversity of habitats. Therefore, it is determined that the diversity of bird communities is affected by the amount of food generated within the habitat and the diversity of habitats. It is determined that the relationship between bird communities and habitat environments in this surveyed region can be basic ecological data for establishing forest management measures to promote the diversity of bird communities.

• The Journal of Information Systems
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• 제15권1호
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• pp.191-213
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• 2006

The purpose of this research is to identify the structure among determining factors focusing on knowledge transfer and analyze and prove the causal relation on knowledge transfer in Korean companies and public corporations. The results from the analysis of data collected in this study are as follows. First, forum among organization related factors has the positive relation with uncertainty in a significant level. Second, the higher the knowledge presentation and the ease of use are among information systems related factors, the lower the ambiguity and uncertainty are. Third, among process related factors, unification has the negative relation with ambiguity and uncertainty in a significant level. Fourth, a better manpower employment contributes to a worse ambiguity and uncertainty. Fifth, ambiguity has a negative relation with knowledge transfer. In conclusion, the factors that lower the ambiguity and facilitate knowledge transfer include information systems, unification, and manpower employment. These factors, however, influence on uncertainty, which turns out to be nothing to do with knowledge transfer.

• International Journal of Highway Engineering
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• 제10권2호
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• pp.101-113
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• 2008

VMS are installed in many Korean highways in oder to give drivers informations such as travel time to destination, congestion and Incident situation. However, some guidelines for install VMS are restricted in only geometric factors although human factors considering driver behavior are very important to affect the VMS installation. Therefore, this paper are focusing on developing and verifying the discriminant model for VMS installation considering human factors. As a result, following outputs are obtained ; (1) developing the discriminant model using human factors of driving simulation experiments in oder to predict driver reading VMS messages safely detour highway. (2) proving that driving experiences in highway, personal driving history, vehicle speed orderly affects VMS installation (3) verifying predictability of developed model by comparing the real values with predicted values. (4) suggesting that VMS should be installed off 3.2Km from the I.C. of rural highway.

• Journal of Korea Water Resources Association
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• 제46권11호
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• pp.1129-1140
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• 2013

Precipitation is one of the important factors in the hydrological cycle. It needs to understand accurate of spatial precipitation field because it has large spatio-temporal variability. Precipitation data obtained through the Tropical Rainfall Monitoring Mission (TRMM) 3B43 product is inaccurate because it has 25 km space scale. Downscaling of TRMM 3B43 product can increase the accuracy of spatial precipitation field from 25 km to 1 km scale. The relationship between precipitation and the normalized difference vegetation index(NDVI) (1 km space scale) which is obtained from the Moderate Resolution Imaging Spectroradiometers (MODIS) sensor loaded in Terra satellite is variable at different scales. Therefore regression equations were established and these equations apply to downscaling. Two renormalization strategies, Geographical Difference Analysis (GDA) and Geographical Ratio Analysis (GRA) are implemented for correcting the differences between remote sensing-derived and rain gauge data. As for considering the GDA method results, biases, the root mean-squared error (RMSE), MAE and Index of agreement (IOA) is equal to 4.26 mm, 172.16 mm, 141.95 mm, 0.64 in 2009 and 17.21 mm, 253.43 mm, 310.56 mm, 0.62 in 2011. In this study, we can see the 1km spatial precipitation field map over Korea. It will be possible to get more accurate spatial analysis of the precipitation field through using the additional rain gauges or radar data.