• The Journal of Fisheries Business Administration
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• v.47 no.2
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• pp.1-14
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• 2016

This study applied the Stochastic Frontier Analysis to estimate which independent variable affects to efficiency of aquaculture household. This study used wage and facility scale as input variables, sales volume as an output variable to estimate efficiency. Also, the study used region, species, water quality to estimate technical inefficiency factors of the model. The data used for this study were obtained by the operating costs survey using 1:1 interview method. The study selected translog production model with technical inefficiency term estimated as half-normal distribution. In addition, the study used pearson and spearman correlation coefficient among efficiency estimating models. Also, the study analysed differences among estimated efficiencies through t-test, and showed us 0.1793 in species, 0.4677 between Geojae and Masan.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.4
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• pp.47-52
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• 2014

Species distribution models have been widely applied in order to assess biodiversity, design reserve, manage habitat and predict climate change. However, SDMs has been used restrictively to the public and policy sectors owing to model uncertainty. Recent studies on ensemble and consensus models have been increased to reduce model uncertainty. This paper was carried out single model and multi model for Corylopsis coreana and compares two models. First, model evaluation was used AUC, kappa and TSS. TSS was the most effective method because it was easy to compare several models and convert binary maps. Second, both single and ensemble model show good performance and RF, Maxent and GBM was evaluated higher, GAM and SRE was evaluated lower relatively. Third, ensemble model tended to overestimate over single model. This problem can be solved by the suitable model selection and weighting through collaboration between field experts and modeler. Finally, we should identify causes and magnitude of model uncertainty and improve data quality and model methods in order to apply special decision-making support system and conservation planning, and when we make policy decisions using SDMs, we should recognize uncertainty and risk.

• Journal of the Korean Society of Safety
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• v.13 no.1
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• pp.70-76
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• 1998

The smoke filling process for the atrium space containing a fire source is simulated using two types of deterministic fire models : Zone model and Field model. The zone model used is the CFAST(version 1.6) model developed at the Building and Fire Research Laboratories, NIST in the USA. The field model is a self-developed fire field model based on Computational Fluid Dynamics(CFD) theories. This article is focused on finding out the smoke movement and temperature distribution in atrium space which is cubic in shape. A computational procedure for predicting velocity and temperature distribution in fire-induced flow is based on the solution, in finite volume method and non-staggered grid system, of 3-dimensional equations for the conservation of mass, momentum, energy, species and so forth. The fire model i. e. Zone model and Field model predicted similar results for the clear height and the smoke layer temperature.

• Journal of Ecology and Environment
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• v.29 no.4
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• pp.331-335
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• 2006

We investigated the distribution of three anuran species, Three-striped pond frogs (Rana nigromaculata), Bullfrogs (Rana catesbeiana), and Narrow-mouthed toads (Kaloula borealis), in an administrative district, Haenam Gun, Junnam Province, Korea using volunteer call surveys. Twenty-eight volunteer call surveyors were assigned to each $2{\times}2km^2$ survey plot. Call surveys on whether the species are present or not were conducted for 5 minutes between 30 minutes after sunset and the midnight on rice fields and ponds from 10 April to 28 August in 2005. Depending on species, call surveys were carried out at seven to 28 plots with average 8.4 to 10.7 visits per the plot. We calculated the detection probabilities and occupancy rates of the three species using four models with three covariates: temperature, humidity, and the amount of water at the habitat. The model average detection probabilities of three anuran species of R. nigromaculata, R. catesbeiana, and K. borealis were 0.53, 0.74, and 0.41 respectively, and the site occupancy rates of them were 0.93, 0.94, and 0.86 respectively. Our results indicate that R. nigromaculata, R. catesbeiana, and K. borealis are common in Haenam Gun.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.7
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• pp.972-980
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• 2022

The butterfly species recognition technology based on machine learning using images has the effect of reducing a lot of time and cost of those involved in the related field to understand the diversity, number, and habitat distribution of butterfly species. In order to improve the accuracy and time efficiency of butterfly species classification, various features used as the inputs of machine learning models have been studied. Among them, branch length similarity(BLS) entropy or color intensity entropy methods using the concept of entropy showed higher accuracy and shorter learning time than other features such as Fourier transform or wavelet. This paper proposes a feature extraction algorithm using RGB color intensity entropy for butterfly color images. In addition, we develop butterfly recognition systems that combines the proposed feature extraction method with representative ensemble models and evaluate their performance.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.6
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• pp.1-13
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• 2015

This study was conducted to develop an environmental index for assessing the vulnerability of areas with invasive alien plants. To that end, "Regional Vulnerability Numerical Index" (RVNI) was developed with a spatial statistical technique and applied to Seoul and Gyeonggi-do area first. The results are as follows. First, RVNI was high in stream areas. Second, RVNI was lowest in mountain areas. It indicates that stream areas are vulnerable to invasive alien plants. In terms of regions, Guri City is most vulnerable and Gapyeong-gun is the least vulnerable. To expand and manage the invasive alien plants, a control protocol should be developed by considering the physiology and ecology by invasive alien plant. Also, related policies should be pursued based on the results. Thus, the findings of this study can be used as baseline data for setting policies for invasive alien species management.

• Korean Journal of Remote Sensing
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• v.28 no.1
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• pp.171-180
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• 2012

The field of wildlife habitat conservation research has attracted attention as integrated biodiversity management strategies. Considering the status of the species surveying data and the environmental variables in Korea, the GARP and Maxent models optimized for presence-only data could be one of the most suitable models in habitat modeling. For make sure applicability in the domestic environment we applied the machine learning species distribution model for analyzing habitats of the Korea water deer($Hydropotes$ $inermis$ $argyropus$) in the $Sapgyocheon$ watershed, $Chungcheong$ province. We used the $3^{rd}$ National Natural Environment Survey data and 10 environment variables by literature review for the modelling. Analysis results showed that habitats for the Korea water deer were predicted 16.3%(Maxent) and 27.1%(GARP), respectively. In terms of accuracy(training/test) the Maxent(0.85/0.69) was higher than the GARP(0.65/0.61), and the Spearman's rank correlation coefficient result of the Maxent(${\rho}$=0.71, p<0.01) was higher than the result of GARP(${\rho}$=0.55, p<0.05). However results could be depended on sites and target species, therefore selection of the appropriate model considering on the situation will be important to analyzing habitats.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.63-69
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• 2014

The oxidizer-rich preburner's combustion tests were fulfilled in the development process of staged combustion cycle rocket engines. The exhaust plume from an oxidizer-rich preburner is relatively transparent because combustion takes place in oxidizer rich state. During hot fire tests a still and infrared images were captured to visualize the plume structure, temperature distribution and so on. In addition, the exhaust plume was numerically investigated to figure out the detailed characteristics. The combustion was not considered for the numerical modeling, but the mixing of exhaust plume with circumstantial air was modeled by species transport model with several turbulence models. The inner structure of plume was configured out by the comparison of numerical results with experimental results, and the validity of applied numerical models was verified.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.1
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• pp.49-62
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• 2020

This study was conducted as a basic study to develop the HSI(Habitat Suitability Index) model of Pelophylax chosenicus based on the research on the ecological and habitat status of Pelophylax chosenicus and the literature research on the HSI model. The habitat variables of Pelophylax chosenicus are the altitude of the spawning pond, the habitat area, the distance from wetland, the soil(aptitude grade for paddy field), the place for eating such as paddy field and wetlands(land cover) and the distance from Predator(Lithobates catesbeianus) distribution area. Based on the existing literature of Pelophylax chosenicus, the results of field surveys and expert opinions, the SI(Suitability Index) model and HSI model were developed and applied to the site to examine the applicability of the HSI model. As a result of application, SI 4 and SI 5 with varying SI values seem to have a major influence on the HSI. In addition, it is considered that the HSI model is an arithmetic mean of SI models, which has a major impact on HSI. The HSI model can be an important basis for the habitat evaluation and restoration model of Pelophylax chosenicus. In particular, it is highly applicable to the selection and evaluation of alternative habitats for Pelophylax chosenicus.

• Journal of Environmental Impact Assessment
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• v.32 no.2
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• pp.83-93
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• 2023

This study was conducted to clarify the environmental variables that affect the appearance of Mauremys reevesii and to understand the relationship between M. reevesii and the variables. Habitat environmental survey was implemented by selecting 17 environmental variables considering ecological characteristics of M. reevesii in the main reservoir in Gurye-gun, the Republic of Korea. And the habitat data on the presence and absence of M.reevesii were analyzed statistically. The habitat suitability model of M. reevesii was described in following equation : logit (p) = -3.68 + (0.17 × leaf litter depth) + (1.55 × vegetation coverage of overstory on land) + (0.71 × coverage of midstory on land) + (0.96 × vegetation coverage of understory on water). This information gained is valuable for better understanding the distribution and how to conserve and promote populations of M. reevesii occurring in the Republic of Korea.