• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.5
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• pp.70-81
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• 2020

Point-by-point data, which is abundantly collected by vehicles with embedded GPS (Global Positioning System), generate useful information. These data facilitate decisions by transportation jurisdictions, and private vendors can monitor and investigate micro-scale driver behavior, traffic flow, and roadway movements. The information is applied to develop app-based route guidance and business models. Of these, speed data play a vital role in developing key parameters and applying agent-based information and services. Nevertheless, link speed values require different levels of physical storage and fidelity, depending on both collecting and reporting intervals. Given these circumstances, this study aimed to establish an appropriate collection interval to efficiently utilize Space Mean Speed information by vehicles with embedded GPS. We conducted a comparison of Probe-vehicle data and Image-based vehicle data to understand PE(Percentage Error). According to the study results, the PE of the Probe-vehicle data showed a 95% confidence level within an 8-second interval, which was chosen as the appropriate collection interval for Probe-vehicle data. It is our hope that the developed guidelines facilitate C-ITS, and autonomous driving service providers will use more reliable Space Mean Speed data to develop better related C-ITS and autonomous driving services.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.292-297
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• 2007

Global warming and climate changes have been major issues for decades andvarious researches have reported their impact on our environment. According to recent researches, increased carbon dioxide ($CO_2$) concentration in the atmosphere is considered as a dominant contributor to global climate changes and thus numerous researches were conducted to control $CO_2$ concentration in the atmosphere. Soil management practices, such as reducing tillage intensity, returning plant residues, and enhancing cropping system have recommended for restoring organic carbon into the soils effectively. However, few studies on soil carbon sequestration have reported for Korean paddy soils. Therefore, evaluation of soil organic carbon (SOC) dynamics in the long-term single rice cropping system is essential in order to find out potential capacity of paddy field as a carbon sink source. The objective of this research was to evaluate SOC dynamics on the long-term single rice cropping system. Research was conducted in the research farm at National Institute of Agricultural Science and Technology, Rural Development Administration, Suwon. Long-term phosphorus and potassium fertilization and lime application didn't significantly affect on SOC compared to controls. We found that SOC contents were increased continually at the long-term composting plots with enhanced rate of carbon storage. In conclusion, continuous incorporation of plant residues (i.e., composting) is recommended to effectively sequester soil carbon for Korean paddy soils. This result implies that continuous composting in a paddy field may contributenot only for increasing SOC in the soils but also for mitigating global warming through reducing carbon dioxide emission into atmosphere. Therefore, we recommend that a strategy or policy measures to encourage farmers to return plant residues continuously for mitigation of global warming as well as soil fertility is being developed.

• Journal of Korean Society of Transportation
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• v.36 no.2
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• pp.67-85
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• 2018

Vehicle platooning through wireless communication and automated driving technology has become realized. Platooning is a technique in which several vehicles travel at regular intervals while maintaining a minimum safety distance. Truck platooning is of keen interest because it contributes to preventing truck crashes and reducing vehicle emissions, in addition to the increase in truck flow capacity. However, it should be noted that interactions between vehicle platoons and adjacent manually-driven vehicles (MV) significantly give an impact on the performance of traffic flow. In particular, when vehicles entering from on-ramp attempt to merge into the mainstream of freeway, proper interactions by adjusting platoon size and inter-platoon spacing are required to maximize traffic performance. This study developed a methodology for establishing operational strategies for truck platoonings on freeway on-ramp areas. Average speed and conflict rate were used as measure of effectiveness (MOE) to evaluate operational efficiency and safety. Microscopic traffic simulation experiments using VISSIM were conducted to evaluate the effectiveness of various platooning scenarios. A decision making process for selecting better platoon operations to satisfy operations and safety requirements was proposed. It was revealed that a platoon operating scenario with 50m inter-platoon spacing and the platoon consisting of 6 vehicles outperformed other scenarios. The proposed methodology would effectively support the realization of novel traffic management concepts in the era of automated driving environments.

• Journal of The Korean Association For Science Education
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• v.34 no.5
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• pp.437-447
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• 2014

Learning progressions (LP), which describe how students may develop more sophisticated understanding over a defined period of time, can inform the design of instructional materials and assessment by providing a coherent, systematic measure of what can be regarded as "level appropriate." We developed LPs for the nature of matter for grades K-16. In order to empirically test Korean students, we revised one of the constructs and associated assessment items based on Korean National Science Standards. The assessment was administered to 124 Korean secondary students to measure their knowledge and submicroscopic representations, and to assign them to a level of learning progression for the particle nature of matter. We characterized the level of students' understanding and models of the particle nature of matter, and described how students interpret various representations of atoms and molecules to explain scientific phenomena. The results revealed that students have difficulties in understanding the relationship between the macroscopic and molecular levels of phenomena, even in high school science. Their difficulties may be attributed to a limited understanding of scientific modeling, a lack of understanding of the models used to represent the particle nature of matter, or limited understanding of the structure of matter. This work will inform assessment and curriculum materials development related to the fundamental relationship between macroscopic, observed phenomena and the behavior of atoms and molecules, and can be used to create individualized learning environments. In addition, the results contribute to scientific research literature on learning progressions on the nature of matter.

• Journal of Korean Society of Forest Science
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• v.111 no.3
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• pp.357-364
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• 2022

We investigated the early growth characteristics of Quercus rubra planted in six regions (Hwaseong, Yangpyeong, Pyeongchang, Samcheok, Chungju, and Gimje) in South Korea in relation to soil physicochemical properties and meteorological factors. Q. rubra (1-0) were planted at a density of 3,000 trees ha^-1. The average height, root collar diameter (RCD), and volume of 8-year-old Q. rubra planted in 2014 were 3.52 m, 3.84 cm, and 0.0023 m³, respectively. The growth parameters of Q. rubra were the highest and lowest in Hwaseong and Pyeongchang, respectively. Correlation analysis among the soil physicochemical properties, meteorological factors, and plantation growth characteristics found that pH was the only soil factor negatively correlated with RCD, and the other soil factors were not significantly correlated with the growth characteristics. However, growth characteristics were positively correlated to average temperature from March to October and daily maximum temperature; and they were negatively correlated to altitude, topology, and the number of rainy days from March to October. In particular, the trees planted in Hwaseong area showed the best early growth characteristics because this area had the highest daily maximum temperature, the x average temperature from March to October, the low altitude, and it is located close to the foot of a mountain. In Pyeongchang, the early growth characteristics were negatively affected by winter cold damage because of the high altitude, low daily minimum temperature, and damage by wild animals. In Hwaseong, meteorological factors such as temperature and altitude were more highly correlated to growth characteristics of Q. rubra than the physicochemical soil properties. These results will provide useful information for determining suitable sites for Q. rubra plantations and for predicting early growth characteristics in response to environmental factors.

• Korean Journal of Ecology and Environment
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• v.48 no.3
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• pp.176-187
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• 2015

In this study, we hypothesized that the size of wintering crane population would change due to the climate factors. We assumed that wintering population size would differ by climate values in January, which is the coldest period in year. Especially, White-naped cranes were able to choose wintering site between Cheorwon and other alternative place where snow coverage had low influence, differing from Red crowned cranes. For this reason, we predicted the population size of White-naped cranes would fluctuate according to the extent of snow coverage in Cheorwon. Therefore we used snow coverage data based on MODIS and climate data from KMA (Korea Meteorological Administration) that are generally used. We analyzed the crane's population size in Cheorwon in January from 2002 to 2014. The temperature in the Cheorwon increased from 2002 to wintering period in 2007~ 2008 and went down, showing the lowest temperature in 2011~ 2012. With this phenomenon, warmth index showed the similar pattern with temperature. Amount of newly accumulated snow (the amount of snow that fallen from 0:01 am to 11:29 pm in a day) was low after 2002, but rapidly increased in 2010~ 2011 and 2011~ 2012. The area of snow coverage rapidly declined from 2002 to 2005~ 2006 but suddenly expanded in wintering period in 2009~ 2010 and 2010~ 2011. Wintering population size of the White-naped cranes decreased as snow coverage area increased in January and the highest correlation was found between them, compared to the other climatic factors. However, the number of individuals of Red crowned cranes had little relationship with general climate factors including snow cover range. Therefore it seems that population size of the Red crowned crane varied by factors related with habitat selection such as secure roosting site and area of foraging place, not by climatic factors. In multiple regression analysis, wintering population of White-naped cranes showed significant relationship with logarithmic value of snow cover range and its period. Therefore, it suggests that the population size of the White-naped crane was affected by snow cover range n wintering period and this was because it was hard for them to find out rice grains which are their main food items, buried in snow cover. The population size variation in White-naped cranes was caused by some individuals which left Cheorwon for Izumi where snow cover had little influence on them. The wintering population in Izumi and Cheorwon had negative correlation, implying they were mutually related.

• The Korean Journal of Archival Studies
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• no.13
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• pp.179-203
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• 2006

This study develops the process and method of official administration documents which have remained ill-balanced like the official documents of the government-general of Chosun(the pro-Japanese colonial government (1910-1945)). At first, the existing Appraisal-theories are recomposed. The Appraisal-Theories of Schellenberg is focused valuation about value of records itself, but fuction-Appraisal theory is attached importance to operational activities which take the record into action. But given that the record is a re-presentation of operational activities, the both are the same on the philosophy aspect. Therefore, in the case that the process - method is properly designed, it can be possible to use a composite type between operational activities and records. Also, a method of the Curve has its strong points in the macro and balanced aspect while the Absolute has it's strength in the micro aspect, so that chances are that both alternate methodologies are applied to the study. Hereby, the existing Appraisal theories are concluded to be the mutually-complemented things that can be easily put together into various forms according to the characteristics of an object and its situation, in the terms of the specific Appraisal methodology. Especially, in the case of this article dealing with the imbalance remains official-documents, it is necessary to compromise more properly process with a indicated useful method than establishing a method and process by choosing the only one theory. In order to appraise the official-documents of the pro-Japanese colonial government (1910-1945), a macro appraisal of value has to be appraised about them by understanding a system, functions and using the historical-cultural evolution, after analysing Disposal Authority. From this, map the record so that organization function maps are constructed regarding the value rank of functions and detailed-functions. After this, establish the appraisal strategy considering the internal environment of archival agencies and based on micro appraisal to a great quantity of records remained and supplying other meaning to a small quantity of records remained for example, the oral resources production are accomplished. The study has not yet reached the following aspects ; a function analysis, historical decoding techniques, a curve valuation of the record, the official gazette of the government general of Chosun( the pro-Japanese government for 1910-1945), an analysis method of the other historical materials and it's process, presentation of appraisal output image. As the result, that's just simply a proposal and we should fill in the above-mentioned shortages of the study through development of all the up-coming studies.

• Journal of Christian Education in Korea
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• v.64
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• pp.51-79
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• 2020

This study was conducted to pursue Christian education with the socially underprivileged in the era of the Corona-19 pandemic. Corona-19 is a disaster which is caused, destroyed and exploited by human being. At the time of the indiscriminately spreading global pendemic, we must work together to overcome our selfish self-centeredness and make an attempt for everyone in need. It is a study on how humans can help each other survive in the era of Corona-19 and its post-corona. The problem is that there is too much discrimination between the state, race, and economic capacity, and in the end, the extreme discrimination of capitalism is appeared in society and across the country. There is no significant difference in the confirmation rate when Corona-19 infiltrates, but there is a big difference between those with and less in mortality. As a result, today's reality is that people who have a hard time living because they have less usually are far more vulnerable to blocking and defeating virus attacks. Unfortunately, this is the current situation. From the standpoint of a large discourse, attention is paid to climate change and ecological environment, and as a micro discourse, a number of societies who live with tremendous discrimination according to the gap between the rich and the poor (it is gender, race, disabled, nationality) that exist in almost all countries on the planet. We need attention to the weak. To this end, discourses on vaccine inequality, discourses on the needs of the disabled, discourses on different racial damages, discourses on polarization and dystopia, and discourses on educational inequality were treated as the reality faced by the socially underprivileged in the Corona 19 pandemic. To explore Christian education with the socially underprivileged, to explore ways of sharing, giving, and solidarity for win-win, discourse on inter-dependence and mutual responsibility of mankind, direct counter-measures for the socially underprivileged, and critical literacy education. He proposed a discourse on Korea, a discourse on Homo sapiens, which must return to being a part of creation, and finally a theology of friendship with the weak. Christian education based on Bible words must go forward in the era of the Corona 19 pandemic, hungry, naked, nowhere to go, sick, but dying because of being unable to get a remedy. He emphasized the need to establish a caring theology of friendship and pursue a life in which thought and practice harmonize. Thus, the paper proposed the spirit of Christian education not only doing something for the socially weak, but with the socially weak in the daily life.