• Journal of Environmental Impact Assessment
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• v.27 no.6
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• pp.685-694
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• 2018

We measured ecological niche space (ENS) using carbon and nitrogen stable isotope ratios of benthic macroinvertebrates to estimate its applicability for large river assessment. In particular, we compared ENSs of selected macroinvertebrates between upper and lower area of Seungchon Weir in Yeongsan River to estimate the impact of weir on biological community. We also measured basic water quality and community indices including benthic macroinvertebrates index (BMI) to estimate their correlations with calculated ENS. ENS was calculated using the Bayesian Stable Isotope in R statistics (package "SIBER"). The results showed that seasonal variations in water quality and community indices were found, but there was no apparent tendency between upper and lower area of the Seungchon Weir in June (before rainy season) and August (after rainy season). However, ENS of benthic macroinvertebrates markedly decreased across the weir in both June and August regardless of changes in water quality. This means the physical change of the stream due to the weir cause decrease of ecological isotopic niche space of benthic macroinvertebrates regardless of water quality, suggesting physical modification by the weir can affect the interaction between habitat condition and macroinvertebrates. Therefore, the ecological isotopic niche space can be a useful supplementary indicator for the river ecosystem assessment.

• Korean Journal of Environment and Ecology
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• v.35 no.4
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• pp.316-335
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• 2021

This study reviewed the change of theory of ecological niche(concepts and definitions) over time to provide a theoretical basis for habitat-related studies of animals and plants. Accordingly, it analyzed and summarized the major discussion trends of ecological niche worldwide in each period from the 1900s to the present. Countries advanced in ecological studies, such as the EU and the USA, have conducted theoretical and empirical studies on the ecological niche since the early 1990s. The concept of the ecological niche was introduced in the early 1900s, developed in the mid-1900s, and advanced from the mid-1900s to the late 1900s. Since the 2000s, the advanced concept has diversified with new developments in technologies and research methods. The factors suggested by theoretical and empirical studies in defining the ecological niche of a species include 1) population dynamics of the target species, 2) all biotic conditions to sustain a population (food relationship and material flow in the food chain), 3) all non-biotic conditions to sustain a population (physical environmental conditions), 4) all direct and indirect interactions between these environmental factors, and 5) response and adaptation mechanisms that include the migratory ability of the target species or genetic diversity and adaptability to change. Unlike such international advancement, there have not been sufficient theoretical, philosophical, and empirical studies of ecological niche in Korea. The concepts and definitions by Greennell, Elton, and Hutchinson were selectively and partially borrowed for empirical studies without full description. Considering that the theory of ecological niche becomes the foundation for habitat-based species conservation and restoration, it is necessary to seek diversification and advancement of theoretical and empirical research and research methods and technological development. It will provide an important foundation for the academic advancement of ecology and for establishing and implementing policies to preserve and restore ecology and biodiversity effectively and successfully in Korea.

• Journal of Wetlands Research
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• v.25 no.3
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• pp.205-212
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• 2023

This study was attempted to find out how the ecological niche and interspecies relationship of Quercus aliena and Q. serrata, which are the main constituents of potential natural vegetation along the riverside of mountains in Korea, under climate change conditions. To this end, soil moisture and soil nutrients were treated with 4 grad ients under climate change conditions with elevated CO₂ and temperature, plants we re harvested at the end of the growing season, growth responses of traits were measured, ecological niche breadth and overlap were calculated, and it was compared with that of the control group(ambient condition). In addition, the relationship between the two species was analyzed by principal component analysis using trait values. As a result, the ecological niche breadth of Q. aliena was wider than that of Q. serrata under the moisture environment conditions under climate change. Under nutrient conditions, the ecological niche of the two species were similar. In addition, the ecological overlap for soil moisture of Q. aliena and Q. serrata was wider than the soil nutrient gradient under climate change. The species with traits in which the increase in ecological niche breadth due to climate change occurred more than the decrease was Q. aliena in both water and nutrient gradients. And in the responses of the population level, due to climate change, the adaptability of Q. aliena was higher than that of Q. serrata under the soil moisture condition, but the two species were similar under the nutrient condition. These results mean that the competition between the two species occurs more severely in the water environment under climate change conditions, and at that time, Q. aliena has higher adaptability than Q. serrata.

• 해운
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• no.6 s.17
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• pp.34-34
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• 2005

• Journal of Korean Society of Forest Science
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• v.68 no.1
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• pp.11-17
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• 1985

Height growth curve to be required for estimating site index was formulated with 10 models based on the average tree height and tree age. Among them, the model of $H=K-ab^A$ was evaluated to be best fit for estimating average tree height(H) with tree age (A). Equations, $H=28.364-26.125(0.818)^A$ and $H=26.331-25.125(0.886)^A$, were situated from the model for estimating average tree height of Larix leptolepis and Pinus koraiensis, respectively (in this case the tree age was categorized into 0 for 5 -year- old tree, 1 for 10 -year- old tree and 2 for 15 -year- old tree ect.). Result of comparing the site indices calculated by the Bryant method, it was proved that the site index of Larix leptolepis was estimated higher than that of Pinus koraiensis within the limits of site index class 6 to 18. On the contrary the site index of Pinus koraiensis turned out to surpass that of Larix leptolepis at the site index class 20 or over.

• Korean Security Journal
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• no.44
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• pp.251-278
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• 2015

Registered security guards carry out police duties as civilian police who are in charge of security service, and so they have a two-fold status: a civilian in terms of a social standing and a policeman in the way that they execute the authority of security. The problem caused by this legal position is that their legal rights and obligation can be unclear in the task-action and working relationship. This paper attempts to study their functions, rights, and legal duties through the interpretation of the related positive law so as to reveal the problems that may spring from this ambiguous status of registered security guards. This endeavor illuminates their legal status specified in the positive law in and around the Act on the police assigned for special guard, observing their functions and the legal duties in the pursuit of their tasks, and ending up pointing out the problems of the positive law. As a result of research work, the most significant problems, even if multifarious, are the avoidance of the state reparation in the responsibility for the illegal behavior in connection with their operation; the unconstitutionality of the disciplinary punishment regulation originated from the entrust with full powers; the imperfection of the rules about the cooperative ties with the police; the possibility of human rights abuse caused by the ban on the labor dispute; the equality problems from the dual pay system; and the inadequacy of the codes about the recruitment qualification and method. This research is intended to help achieve the purpose of the security of national critical facilities through the smooth execute of duties as well as the protection of the guards' rights. Besides, the key focuses posed in this paper are worthy of being developed more accurately through the following researches.

• Korea journal of population studies
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• v.35 no.1
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• pp.131-149
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• 2012

This study examined the effect of parental socioeconomic position on the association between birth outcomes and infant mortality in early and late 2000's. Linked Birth and Infant Death data sets from 2001 to 2003 (T1) and from 2006 to 2008 (T2), provided by the Korea National Statistical Office, were used for analysis. Birth outcomes were categorized into four groups: normal term, small-for-gestational age (SGA), large-for-gestational age (LGA) and intrauterine growth retardation (IUGR). Infant death was defined as the death of a live-born child under one year of age; indicators of parental socioeconomic position were limited to parental education and occupation. The results showed that T2 infant mortality hazard ratios of SGA and IUGR have increased compared to T1. Particularly, preterm and low birth weight babies with shorter gestational age and lighter birth weight than T1 have elevated in T2, possibly indicating that population quality might be continuously aggravated. Moreover, the effect of maternal age on infant mortality has disappeared, rather that of parents' socioeconomic position has increased during the periods, which entailed growing disparities in infant mortality by their social class. Further studies should be therefore done to estimate the effect of parental socioeconomic position on the relationship between birth outcomes and infant mortality in the near future.

• Journal of the Korean earth science society
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• v.41 no.3
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• pp.307-319
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• 2020

The purpose of this study was to determine whether there are differences in the verbal interactions of earth science gifted depending on their communications structures and group status in small group activities. To this end, a small group activity was conducted to measure the density of the earth, and 8 small groups were selected, including 4 co-ownership type and 4 monopolistics type groups with different communication structures. And then, the framework was developed for analyzing verbal interactions to compare the differences in characteristics between small groups. The results are as follows. First, regardless of the communication structures, there were showing a simple pingpong-type communication structures for all small groups. Second, negative interactions such as 'restraint', 'command', 'complaint', and 'lack of confidence' predominantly appeared in all small groups. Third, the students in the status of out-lookers in small groups were mainly verbal interactions, such as instructing the other person, acting against the other person's actions, and expressing dissatisfaction with the attitudes and abilities of members. Therefore, teachers should guide students to use higher-level verbal interactions in their group activities in small group activities, and engage in students communication to prevent negative interactions from occurring. The teachers also need to check the level of achievement for students in the status of out-lookers in advance and guide them to participate more actively in small group activities. This study is meaningful in that it can be sued to design teaching and learning to improve students' problem solving and communication skills.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.605-612
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• 2014

This study was conducted to predict the changes of yearly productive area distribution for Quercus mongolica under climate change scenarios. For this, site index equations by ecoprovinces were first developed using environmental factors. Using the large data set from both a digital forest site map and a climatic map, a total of 48 environmental factors including 19 climatic variables were regressed on site index to develop site index equations. Two climate change scenarios, RCP 4.5 and RCP 8.5, were then applied to the developed site index equations and the distribution of productive areas for Quercus mongolica were predicted from 2020 to 2100 years in 10-year intervals. The results from this study show that the distribution of productive areas for Quercus mongolica generally decreases as time passes. It was also found that the productive area distribution of Quercus mongolica is different over time under two climate change scenarios. The RCP 8.5 which is more extreme climate change scenario showed much more decreased distribution of productive areas than the RCP 4.5. It is expected that the study results on the amount and distribution of productive areas over time for Quercus mongolica under climate change scenarios could provide valuable information necessary for the policies of suitable species on a site.

• Journal of Korean Society of Forest Science
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• v.102 no.3
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• pp.437-445
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• 2013

This study was conducted to develop site index equations and to estimate productive areas of Quercus acutissima by ecoprovince in Korea using environmental factors. Using the large data set from both a digital forest site map and a climatic map, a total of 48 environmental factors including 19 climatic variables were regressed on site index to develop site index equations. Four to six environmental factors for Quercus acutissima by ecoprovince were selected as independent variables in the final site index equations. The result showed that the coefficients of determination for site index equations were ranged from 0.30 to 0.41, which seem to be relatively low but good enough for the estimation of forest stand productivity. The site index equations developed in this study were also verified by three evaluation statistics such as the estimation bias of model, precision of model, and mean square error of measurement. According to the evaluation statistics, it was found that the site index equations fitted well to the test data sets with relatively low bias and variation. As a result, it was concluded that the site index equations were well capable of estimating site quality. Based on the site index equations of Quercus acutissima by ecoprovince, the productive areas by ecoprovince were estimated by applying GIS technique to the digital forest site map and climate map. In addition, the distribution of productive areas by ecoprovince was illustrated by using GIS technique.