• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.236-248
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• 2019

Green belts can help to set boundary for city growth, provide ecological protection system and enhance the resilience of Beijing. During the implementation period of the current overall city planning of Beijing, the proportion of green space varies much among the sub-districts, villages and towns involved in the two green belts in the research. With this as starting point, by researching the correlations of 'city system factors' and 'planning policy factors' with the change in the scale of green space, the paper discussed the influential factors of implementing the planning of green space of Beijing, and conducted quantitative research, with such possible influential factors classified into 'city system factors' and 'planning policy factors'. Through multiple linear regression model, the paper tested the correlations of city system factors and planning policy factors (independent variable) with the increment in the construction land in green belts (dependent variable). Through influence to population aggregation and the expansion force of construction land, city system factors such as mountain land and water, house rent of unit area, accessibility of public transport and the newly-defined state-owned construction land generate correlation with the change in the scale of construction land in green belts.

• KIEAE Journal
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• v.13 no.6
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• pp.105-111
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• 2013

This study aims to suggest the PV lightshelf and to evaluate the power performance of the photovoltaic systems easily mounted on the windows. For the study, the suggested systems consist of two parts as fixed and movable PV modules. Also, tempered glass and polycarbonate are used on the surface protection materials for solar cells of PV lightshelf. By using polycarbonate, the weight of PV lightshelf is lighter about 20%. The field tests are performed for five days by using real size models. The voltage, current and electric powers are measured as basic performances of PV lightshelf. Also, the irradiation, brightness and module surface temperature are measured as outside conditions. As results, the power performance of tempered glass PV lightshelf shows about 11(%) higher thant that of polycarbonate PV lightshelf. And the power performance shows about 5(%) higher in a horizontal system. This results could be used to develop the effective PV lightshelf in next study.

• The Journal of Fisheries Business Administration
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• v.51 no.2
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• pp.51-69
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• 2020

The purpose of this study is to construct an outlook model that is consistent with the "Fisheries Outlook" monthly published by the Fisheries Outlook Center of the Korea Maritime Institute(KMI). In particular, it was designed as a partial equilibrium model limited to abalone items, but a model was constructed with a dynamic ecological equation model(DEEM) system taking into account biological breeding and shipping time. The results of this study are significant in that they can be used as basic data for model development of various items in the future. In this study, due to the limitation of monthly data, the market equilibrium price was calculated by using the recursive model construction method to be calculated directly as an inverse demand. A model was built in the form of a structural equation model that can explain economic causality rather than a conventional time series analysis model. The research results and implications are as follows. As a result of the estimation of the amount of young seashells planting, it was estimated that the coefficient of the amount of young seashells planting from the previous year was estimated to be 0.82 so that there was no significant difference in the amount of young seashells planting this year and last year. It is also meant to be nurtured for a long time after aquaculture license and limited aquaculture area(edge style) and implantation. The economic factor, the coefficient of price from last year was estimated at 0.47. In the case of breeding quantity, it was estimated that the longer the breeding period, the larger the coefficient of breeding quantity in the previous period. It was analyzed that the impact of shipments on the breeding volume increased. In the case of shipments, the coefficient of production price was estimated unelastically. As the period of rearing increased, the estimation coefficient decreased. Such result indicates that the expected price, which is an economic factor variable and that had less influence on the intention to shipments. In addition, the elasticity of the breeding quantity was estimated more unelastically as the breeding period increased. This is also correlated with the relative coefficient size of the expected price. The abalone supply and demand forecast model developed in this study is significant in that it reduces the prediction error than the existing model using the ecological equation modeling system and the economic causal model. However, there are limitations in establishing a system of simultaneous equations that can be linked to production and consumption between industries and items. This is left as a future research project.

• Korean System Dynamics Review
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• v.16 no.1
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• pp.5-23
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• 2015

The purpose of this study is to analyze the land-use changes in the coastal areas using system dynamics modeling and to provide directions for effective management to maintain coastal dune areas. This research process consists of four steps: First, we built the basic model based on the causal loop diagram which was analyzed the land-use change of Sindu-ri Coastal Dune. Second, a time series land-use change map using Arc Map was established. Third, the validity of the basic model was tested. Finally, three simulations were performed for the cut over area($100,000m^2/y$, $150,000m^2/y$, $200,000m^2/y$) of windbreak for maintaining the coastal dune areas. Simulation of the basic model showed that the area of the coastal dune will be consistently decreased. Based on the simulation, if windbreak were cut down $150,000m^2/y$, windbreak area will be restored to the target area in 2019. This study has the limitation which the simulation is progressed with a limited variable: area. Therefore, the modeling of coastal dune should be reflected various variables in the further study.

• Korean Journal of Childcare and Education
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• v.11 no.2
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• pp.87-108
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• 2015

The purpose of this study was to investigate the difference in Korean 4-year-olds' cognitive development depending on variables concerning ecological system variables, predictive influences among these variables, and different predictive patterns between working mothers and non-working mothers. The subjects consisted of 998 4-year-olds, derived from the Korean Child Panel data of 2012. The results were as follows: First, 4-year-olds' cognitive development was different depending on their sex, education level of mother and father, mothers' working status, quality of home environment, and mothers' involvement in children's life in their institution. Second, mothers' involvement in children's life in their institution, children's sex, quality of home environment, and mothers' working status predicted 4-year-olds' cognitive development. Third, there was a different pattern of predictive influence among variables according to the mothers' working status. The mothers' involvement in their children's lives in their institution and children's sex was proved to be important in both, but that was more significant in working mothers, and the quality of home environment predicted cognitive development only in working mothers. These results were discussed in terms of necessity of the Korean national policy to support young children's cognitive development efficiently, especially for working mothers.

• KIEAE Journal
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• v.10 no.3
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• pp.43-50
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• 2010

Natural lighting is directly connected with our mental and physical health. For working or learning effect, the proper natural lighting is required for improving our living conditions. School facilities, especially, are the place where includes students' ordinary activities with learning behaviors during the school years from elementary to high school. This study was carried out for the purpose introducing a basic database in that planning a school by researching on the actual in the natural lighting system of some schools' classroom, estimating, and analyzing through a simulation, which resulted in a method of improving the natural lighting system. As a result of measuring and analyzing Daylight Factor(DF) during the time from 9 am to 3 pm when students are activating in their classroom, generally DF range of the sides near to window and aisle seats zone are not distributed well. Besides, two out of four school which are researched would not reach the standards of the law for school sanitary while rest of the schools meet the standards; Average DF 5% and Minimum DF 2%. And the result of a simulation by RADIANCE program shows the most appropriate DF range when it is applied in variable numbers about an oriehows the- South-east 15, south-east 30, south-east 45, south-west 15, south-west 30, and south-west 45 degrees. When it is applied in the variable numbers about glass transmittance - 60%, 70%, and 80% in condition facing south of a classroom, the result shows that the DF range of 80% transmittance is relatively higher than other glasses in the classroom. Thus, when a school is built, plans for an orientation is necessary for improve of elementary schools' environment with the glass installation which is made for high transmittance and is regarded with the students' activities time.

• KIEAE Journal
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• v.17 no.5
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• pp.69-76
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• 2017

Purpose: This study aimed at developing an Artificial Neural Network (ANN) model for predicting the amount of cooling energy consumption of the variable refrigerant flow (VRF) cooling system by the different set-points of the control variables, such as supply air temperature of air handling unit (AHU), condenser fluid temperature, condenser fluid pressure, and refrigerant evaporation temperature. Applying the predicted results for the different set-points, the control algorithm, which embedded the ANN model, will determine the most energy efficient control strategy. Method: The ANN model was developed and tested its prediction accuracy by using matrix laboratory (MATLAB) and its neural network toolbox. The field data sets were collected for the model training and performance evaluation. For completing the prediction model, three major steps were conducted - i) initial model development including input variable selection, ii) model optimization, and iii) performance evaluation. Result: Eight meaningful input variables were selected in the initial model development such as outdoor temperature, outdoor humidity, indoor temperature, cooling load of the previous cycle, supply air temperature of AHU, condenser fluid temperature, condenser fluid pressure, and refrigerant evaporation temperature. The initial model was optimized to have 2 hidden layers with 15 hidden neurons each, 0.3 learning rate, and 0.3 momentum. The optimized model proved its prediction accuracy with stable prediction results.

• The Korean Journal of Ecology
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• v.8 no.4
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• pp.179-196
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• 1985

By using temperatures as a key variable, a simulation model was constructed to predict the size and developmental speed for the German cockroach population. The following three research steps were conducted to implement the individual simulation technique to represent the basic life system of the cockroach. First, informations on developmental periods and survival rates in each life stage were obtained through rearing experiments at five different temperatures. Secondly, biological parameters needed for modeling were obtained based on these rearing results. The logistic equation was applied to calculating the developmental speed, while the averages of survival rates were utilized as parameters determining population size. And thirdly, a basic life model was constratued in a stimulative framework in FORTRAN for predicting the populating development on the individual basis. For this purpose the biological characteristics, such as life stage, age in days, developmental speed, fecundity, etc., were assigned as an inherent attribute of the transactiion so that they could accompany each individual automatically all through the simulation. This gave the model flexibility and applicability in representing the isnect life system. The save memory space in computer programing, two files were utilized in translocating the individual informations each other as time proceeded. The developed model could be effectively used as a strategic tool in interpreting and managing the cockroach population. It was also suggested in this study that the individual simulation could efficiently serve as a basis to formulate a fundamental framework on which the advanced and complex life process could be built.

• Korean Journal of Ecology and Environment
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• v.54 no.4
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• pp.363-373
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• 2021

An ecological niche is defined as the specific role of a species influenced by time, space, and other resources. By investigating overlaps between ecological niches of different species, we could estimate the degrees of interspecific competition. Such studies often use geographic information systems (GIS) to discover niche overlaps between species. In this study, we used GIS to estimate the spatial niches of two Korean frog species(Pelophylax nigromaculatus and P. chosenicus). This enabled us to predict their geographic distributions in order to identify their coexistence regions and distribution patterns. The results confirmed that altitude was an important variable for predicting their distribution, with a correlation with their climatic range. Spatial distributions of the two frog species were highly overlapped, as the distribution range for P. nigromaculatus included most of the range of P. chosenicus, showing a sympatric distribution pattern. Within the coexisting regions, however, the presence sites for the two species did not overlap, implying weak competition. To confirm the principal factors influencing their competitive relationship and reasons for their sympatric distribution pattern, we need more detailed in-depth studies on the diverse environmental variables within the regions where the two species coexist. By doing so, we would be able to identify various mechanisms for avoiding competition in sympatric frog species.

• KIEAE Journal
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• v.17 no.4
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• pp.67-74
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• 2017

Purpose: As the recent climate environment changes so rapidly, environmental problems such as hot weather and fine dust have occurred, and interest in environmental policies and technology development is increasing in countries around the world. Similarly in the Architecture, researches to reduce greenhouse gas emissions and to reduce energy application are actively conducted. Looking at previous studies, it is analyzed that the electric VRF is more energy efficient than the gas engine VRF. However, energy costs have changed due to recent price hikes and discounts on gas charges due to high electricity consumption in summer. Method: In this study, the actual building of Gas Engine VRF system was modeled using SketchUp program, and EnergyPlus was used to simulate actual building. Also, Electric VRF system was simulated, and compared with Gas Engine VRF system. Result: The total secondary energy requirement of Electric VRF system was 19.6% less than that of the Gas Engine VRF system, But when analyzing with primary energy requirement, EHP used 15.8% more energy. CO2 emissions were also estimated to be 16.9% more EHP. Energy costs were 14.8% more in Electric VRF systems, because their electricity charges are 0.6 to 160% more expensive than gas charges.