• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.8
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• pp.648-656
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• 2002

This paper presents the identification of temperature-dependent hysteresis of an electro-rheological (ER) fluid under various operating temperatures using the Preisach model. As a first step, polymethylaniline (PMA) particles are prepared and mixed with silicone oil to make an ER fluid. A couette type electroviscometer is then employed to obtain the field-dependent shear stress. In order to show the suitability of the Preisach model to predict a physical hysteresis phenomenon of the ER fluid, two significant properties; the minor loop property and the wiping-out property are experimentally examined under three dominant temperature conditions. Subsequently, the Preisach model for the PMA-based ER fluid is identified using experimental multiple first order descending (FOD) curves. The effectiveness of the identified hysteresis model is verified in the time domain by comparing the predicted field-dependent shear stress with the measured one under the both specified and unspecified temperatures. In addition, the hysteresis model proposed in this work is compared to Bingham model.

• Journal of Korean Home Economics Education Association
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• v.27 no.2
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• pp.53-75
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• 2015

In the modern society, the adolescence needs the career development competency which makes them probe changing social phenomenon critically and use the given environment and resources progressively. Thus, adolescence should be offered with the career development competency education, but the education in the school fields remains as school entrance coaching focusing on the academic clique and career coaching as a mere job education. As a result, the study connection between high school and university was destroyed and it caused students' study-unfitness and dropouts after the university entrance. Hence, career education to culture major suitability of high school students in the new paradigm should be developed through high school-university connection. So, this study developed a career education program through the collaboration among the professor of college of human ecology, a home economics specialist, undergraduates majoring in human ecology, and a high school student, using the ADDIE model. The result of this study is as followed. First, this study searched for the direction of the program for the career development competency reinforcement of high school students. Second, the program arranged the newest issues of each department of human ecology to make high school students come in contact with and study them easily, aiming at cultivation of major suitability of high school students. Third, the study established the teaching-learning materials that is managed by the high school-college of human ecology committee. Fourth, this program will be the good opportunity for students who are interested in departments of human ecology to check their major suitability.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.5
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• pp.45-58
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• 2020

This study was conducted to comprehend the spatial distribution characteristics, habitats and appearances of Hydropotes inermis by using the biotope mapping in Daebudo Island, Ansan-si. The result is base data to understand status and manage potential inhabitation of Hydropotes inermis in Daebudo Island through the Maximum Entropy model. The study used 105 traces from the primary investigation and 452 traces in the secondary investigation. The biotope types were distinquished Hydropotes inermis habitats largest from the order of natural forest (15.1%), natural coast (13.7%), marshy cultivated land (12.6%), and dry cultivated land (11.7%), and from the inhabitation trace results. Hydropotes inermis appearanced biotope types were the greatest in the order of cultivated land (49.73%) > forest (18.85%) > coast (7.00%) > grassland (6.28%). Since forests in Daebudo Island have low slope and altitude, it was concluded that Hydropotes inermis would live in most of the forests. A high number of Hydropotes inermis was found to appear in areas where the grassland is formed including cultivated lands (include unused paddies and fields) and marshy grasslands, which would result in direct damage of crops. According to the Maxent modeling analysis that used location information of Hydropotes inermis, the AUC value was 0.635 based on the ROC curve. In Daebudo Island, areas with over 0.635 potential inhabitation value are distributed all over the place, and it was concluded that each population would have a different scope of influence and home range. Hydropotes inermis living in Daebudo Island have high habitat suitability mainly around the cultivated lands near the roads, but due to the bare lands and roads, it is expected that their habitats would be fragmented and damaged, which would have a direct and indirect effect in maintaining the Hydropotes inermis population. Also, considering habitat disturbance, diverse methods for reducing damage including capturing some individuals within the limit that does not disperse Hydropotes inermis population in Daebudo Island must be carried out.

• Journal of Korean Society of Forest Science
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• v.97 no.3
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• pp.255-265
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• 2008

This study is aiming at providing the useful information for successful implementation of the forest resource promotion policy through analyzing the impacting factors and their relationships on policy accomplishment and policy effectiveness in executing the forest resource promotion policy. Interview survey was conducted on the stake-holders such as government officers and civilians who have direct or indirect influences on the establishment and execution of the forest resource promotion policy. The forest resource promotion policy was heuristically analyzed by using the LISREL (Linear Structural RELations) Model. The policy accomplishments of forest resource promotion significantly showed the positive relations with the suitability of problem recognition, the suitability of policy decision-making and rationality of policy execution, while the degree of policy support and the policy accomplishments were having significant impacts upon the policy effectiveness. Since the path coefficients between the latent variables and observed variables and among the latent variables mostly showed the positive relations significantly, the forest resource promotion policy was evaluated very successful in terms of policy accomplishments and policy effectiveness.

• Ecology and Resilient Infrastructure
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• v.6 no.3
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• pp.145-153
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• 2019

The present study performed the impact of the change of low-flow channel on aquatic habitat in a reach of the Wonju-cheon Stream, Korea. The target species was Zacco platypus, a dominant species in the middle- and upper-stream of Wonju Cheon. The River2D model was used for the computation of the flow and the habitat suitability index model was used to estimate the quantity and quality of fish habitat using habitat suitability curves. First, for the restoration to low-flow channel, the restoration was conducted in a form close-to-nature flow channel, and the width of the low-flow channel was expanded and reduced. The results indicated that the Weighted Usable Area (WUA) of the target species improved by about 72% when the width of the low-flow channel was expanded, and that the fish habitat decreased by about 25% when the width of the low-flow channel was reduced.

• The Korean Journal of Applied Statistics
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• v.32 no.2
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• pp.291-300
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• 2019

This study investigates the characteristics of evaluation measures for classification models on a binary response variable in order to evaluate their suitability for use. Six measures are considered: Accuracy, Sensitivity, Specificity, Precision, F-measure, and the Heidke's skill score (HSS). Evaluation measures are reformulated using x(ratio of actually 1), y(ratio predicted by 1), z(ratio of both actual and predicted by 1) from the confusion matrix. We suggest two necessary conditions to assess the suitability of the evaluation measures. The first condition is that the measure function is constant for x and y in the case of a random model. The second condition is that the measure function is increasing for z and decreasing for x and y. Since only HSS satisfies the two conditions, that is always appropriate as an evaluation measure for the classification model on the binary response variable, and the other measures should be used within a limited range.

• Phonetics and Speech Sciences
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• v.14 no.2
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• pp.29-38
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• 2022

This study aimed to analyze the speech appearing in the National Institute of Korean Language's Daily Conversation Speech Corpus (2020) and reveal how the speech rate and the frequency of turn-taking affect the change in prosody units. The analysis results showed a positive correlation between intonation phrase, word phrase frequency, and speaking duration as the speech speed increased; however, the correlation was low, and the suitability of the regression model of the speech rate was 3%-11%, which was weak in explanatory power. There was a significant difference in the mean speech rate according to the frequency of the turn-taking, and the speech rate decreased as the frequency of the turn-taking increased. In addition, as the frequency of turn-taking increased, the frequency of intonation phrases, the frequency of word phrases, and the speaking duration decreased; there was a high negative correlation. The suitability of the regression model of the turn-taking frequency was calculated as 27%-32%. The frequency of turn-taking functions as a factor in changing the speech rate and prosodic units. It is presumed that this can be influenced by the disfluency of the dialogue, the characteristics of turn-taking, and the active interaction between the speakers.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.2
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• pp.47-55
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• 2016

In this study, WUA (Weighted Usable Area) based on the Instream Flow Incremental Methodology (IFIM) was calculated to determine ecological flow at JeonJu-Cheon by using River2D model. To calibrate River2D, simulation results for low flow conditions of River2D were compared with calibrated HEC-RAS simulation results and the optimum parameters were determined. The results were RMSE (0.18), NSE (0.71) and coefficient of determination (0.78) for velocity and RMSE (0.02), NSE (0.71), coefficient of determination (0.73) for water depth. The result shows that the model successfully simulates the water flows. A selected target fish species to build the habitat suitability index were composed of Zaccoplatypus and Coreoleuciscus splendidus. These species showed the highest occurrences over the past decade in f ish monitoring. Also, The WUA-Discharge curve was calculated with the suitability index in a medium flow conditions. From the result, WUA is changed according to flowrate. In the flowrate-WUA/A graph, ecological flow can be determined at $1.8{\sim}2.0m^3/s$ for Zaccoplatypus $2.0m^3/s$ and Coreoleuciscus splendidus $1.8m^3/s$ at JeonJu-Cheon upstream. When compared with flow-duration analysis, it is demonstrative that simulation results fitted ecological flow considering quantity of available habitat for each fish species.

• Journal of Korea Water Resources Association
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• v.54 no.11
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• pp.985-998
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• 2021

In general, the upstream dam changes downstream flow regime dramatically, i.e., from natural flow regime to hydropeaking flows. This study investigates the impact of the natural flow pattern on downstream fish habitat in a regulated river in Korea using the physical habitat simulation. The study area is a 13.4 km long reach of the Geum-gang River, located downstream from the Yongdam Dam, Korea. A field monitoring revealed that three fish species are dominant, namely Zacco platypus, Coreoleuciscus splendidus, and Opsariichthys bidens, and they account for 70% of the total fish community. Specially, Opsariichthys bidens is an indigenous species in the Geum-gang River. The three fish species are selected as target fish species for the physical habitat simulation. The Nays2D model, a 2D shallow water equation solver, and the HSI (Habitat Suitability Index) model are used for hydraulic and habitat simulations, respectively. To assess the impact of the natural flow pattern, this study uses the annual natural flow regime and hydropeaking flows from the dam. It is found that the natural flow regime increases significantly the Composite Suitability Index (CSI) in the study reach. Then, using the Building Block Approach (BBA), the scenarios for the modifying dam operations are presented in the study reach. Both Scenario 1 and scenario 2 are proposed by using the hydrological method considering both magnitude and duration of the inflow and averaging the inflow over each month, respectively. It is revealed that the natural flow regime embodied in scenario 1 and scenario 2 increases the Weighted Usable Area (WUA) significantly, compared to the hydropeaking flows. In conclusion, the modifying the dam operations by restoring to the natural flow pattern is advantageous to fish community.

• Journal of Ecology and Environment
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• v.46 no.4
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• pp.316-323
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• 2022

Background: We developed a habitat suitability index (HSI) model for Pedicularis hallaisanensis, a Grade II Endangered Species in South Korea. To determine the habitat variables, we conducted a literature review on P. hallaisanensis with a specific focus on the associated spatial factors, climate, topography, threats, and soil factors to derive five environmental factors that influence P. hallaisanensis habitats. The specific variables were defined based on the collected data and consultations with experts in the field, with the validity of each variable tested through field studies. Results: Mt. Seorak had a suitable habitat area of 2.48 km² for sites with a score of 1 (0.62% of total area) and 0.01 km² for sites with a score of 0.9. Mt. Bangtae had a suitable habitat area of 0.03 km² for sites with a score of 1 (0.02% of total area) and 0 km² for sites with a score of 0.9. Mt. Gaya showed 0.13 km² of suitable habitat for sites with a score of 1 (0.17% of total area) and 0 km² for sites with a score of 0.9. Lastly, Mt. Halla showed 3.12 km² of suitable habitat related to sites with a score of 1 (2.04% of total area) and 4.08 km² of sites with a score of 0.9 (2.66% of total area). Mt. Halla accounts for 73.1% of the total core habitat area. Considering the climatic, soil, and forest conditions together with standardized collection sites, our results indicate that Mt. Halla should be viewed as a core habitat of P. hallaisanensis. Conclusions: The findings in this study provide useful data for the identification of core habitat areas and potential alternative habitats to prevent the extinction of the endangered species, P. hallaisanensis. Furthermore, the developed HSI model allows for the prediction of suitable habitats based on the ecological niche of a given species to identify its unique distribution and causal factors.