• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.353-367
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• 2015

The goal of this study is to analyze the feedback structure of habitat changes of the Whooper Swan in Eulsukdo using system thinking to suggest a management plan for ecosystem health. Using the causal loop diagrams of population changes between Whooper Swan and other bird species in Eulsukdo, we found that the environmental changes in the roosting and foraging area affect the Whooper Swan's population. The causal loop diagrams of the Whooper Swan's roosting area indicated that the environmental changes (e.g., water level, noise, bird watching, and other experience activities) may influence their population density variation. In addition, the casual loop diagrams of the Whooper Swan's foraging area showed that the Whooper Swan's population was affected by various variables that included area factors such as surface area of freshwater, frozen water, salinity, and density of Scirpus planiculmis. Furthermore, through the integrated causal loop diagram, cumulative discharge of Nakdong estuary weir and building activities were identified as the variables that affect the population of the Whooper Swan. Thus, we selected this area as the strategic point to establish a management plan for the Whooper Swan's habitat. The results of this study will help in decision making of a long-term management plan for sustaining the environmental health of the ecosystem in Eulsukdo.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.4
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• pp.573-583
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• 2015

Objectives: This study was carried out to evaluate the effect of noise exposure and aging on changes in hearing threshold level and the relationship between age and noise. Materials: The author selected 274 male shipyard and assembly line workers as the noise exposed group and 582 males not exposed to noise as the general population group. Data were collected from five years of consecutive annual audiometric tests performed from 2008 to 2012. Results: In the general population and noise exposed groups, there was a reverse phenomenon that hearing threshold level for 2009 was lower than that of 2008, which seemed to be due to the learning effect, but from 2010 hearing threshold level increased. In the noise exposed group, the mean hearing threshold level in the left ear was significantly higher than that for right ear. In the general population group, the older was the age, the higher was the hearing threshold level, especially at 4000 Hz. In the general population and noise exposed groups, frequency, age group and noise exposure independently affected hearing threshold level, and there was no relationship between age and noise exposure. Over all frequencies, the change of hearing threshold level was larger in the noise exposed group than in the general population group. In the noise exposed group below thirty years old, the change at 4000 Hz was remarkable. Conclusions: Age and noise exposure seem to affect hearing threshold level independently and contribute to an additive effect on hearing threshold level.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.231-235
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• 1988

Population changes of aerobic bacteria, yeasts, and lactic acid bacteria ware investigated during the fermentation of Kimchis containing 0, 1, 2, 4, and 6% garlic at $21^{\circ}C$. The numbers of aerobic bacteria increased during the first 2 days and decreased thereafter. The higher the garlic concentration of the Kimchis was, the smaller the increase of the aerobic bacterial population was during the initial periods of the fermentations. Garlic concentrations that showed the largest population difference between them after 2-days fermentation were 1% and 2%. The population of lactic acid bacteria also increased only during the first 2 days and was held thereafter. Lactic acid bacterial population increased more at higher garlic concentrations during the initial period of the fermentations and major microorganisms contributed to the increase were Lactobacillus brevis and low acid-producing lactbacilli. Changes of yeasts at the different garlic concentrations during the fermentations were not apparent.

• Journal of Korean Society on Water Environment
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• v.38 no.5
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• pp.240-246
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• 2022

Water and energy are inextricably linked and referred to as 'Water-Energy Nexus'. Recently, this topic has been drawing a lot of attention from various studies due to the exacerbated water availability. Korea's water and energy consumption has been increasing consistently, which calls for better management. This paper aims to identify changes in electricity consumption in relation to water intake and purification processes. Using Log Mean Divisia Index (LMDI) Decomposition Analysis method, this study attributes the changes to major factors such as; Total population (population effect), household/population (structure effect), GDP/household (economic effect), and water-related energy use/GDP (unit effect). The population effect, structure effect, and economic effect contributed to an increase in water-related electricity consumption, while the unit effect contributed to a decrease. As of 2019, the economic effect increased the water supply sector's electricity consumption by 534 GWh, the population effect increased by 73 GWh, and the structure effect increased by 243 GWh. In contrast, the unit effect decreased the electricity consumption by -461 GWh. We would like to make the following suggestions based on the findings of this study; first, the unit effect must be improved by increasing the energy efficiency of water intake and purification plants and installing renewable energy power generation facilities. Second, the structure effect is expected to increase over time, and to mitigate it, water consumption must be reduced through water conservation policies and the improvement of water facilities. Finally, the findings of this study are expected to be used as foundational data for integrated water and energy management.

• Journal of the Korean Regional Science Association
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• v.40 no.2
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• pp.21-38
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• 2024

Understanding the interrelationship between regional population dynamics and cultivated land is crucial for promoting regional economic vitality and enhancing food security. While prior research often addressed population migration and changes in crop area separately, this study employs a Panel Vector Auto Regression Model to examine the dynamic interaction between regional population shifts, changes in crop area, and the influx of foreign workers in agriculture. The results reveal a reciprocal relationship between population influx and crop area, indicating a negative impact on each other. Moreover, the analysis demonstrates that an expansion in crop area, particularly in field cultivation, significantly correlates with an increase in foreign workers. These findings underscore the mutual influence of labor shortages and diminished land availability in agriculture, with the influx of foreign workers potentially offering a positive impact on addressing structural challenges in rural areas.

• Korea journal of population studies
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• v.18 no.2
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• pp.23-50
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• 1995

This study describes the effects of demographic transition on the environmental changes in Korea. The basic framework of this study is a path model. This study analyzes the effects of population growth, urbanization and industrialization on the environmental deterioration. In doing this, this study illustrates the changing patterns of population growth, urbanization and industrialization. This study also shows the changing patterns of environmental conditions, focusing on air pollution, water pollution and wastes. Finally, this study deals with the consequences of the environmental deterioration, especially focusing on the changing quality of life in Korea.

• Korean System Dynamics Review
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• v.11 no.3
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• pp.105-126
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• 2010

The ecology of house swallow is closely related to the humans life because their life depend on the human settlements conditions and environments. 30 years ago house swallows are very common at the country side, but recently they are very rare. Almost the number of house swallows decrease as 1 of hundredth during 20 years. Why this dramatic population decrease are happening in the ecology of house swallow? The Population size impacted by many factors such as nesting, breeding, feeding, returning. The objective of this paper is to analyse the population dynamics of the ecology of House Swallow. This paper focuses on the important ecological changes-nests, foods, and return rates from wintering area-associated with recent country side development. In this paper, we explore the feedback loops of population dynamics and simulate the policy scenario model.

• Journal of Plant Biology
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• v.10 no.1_2
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• pp.21-30
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• 1967

The aim of present study is to elucidate the relationship between decay rate of soil organic matter, and the change of soil microbial population under the oak and pine forest soils in Kwang-nung plantation stand. The results obtained are as follows: 1) The correlation coefficient between decay rate and the soil bacteria is 0.84 and fungi 0.93. 2) The distribution of soil microbial population is higher in both F horizon of the oak forest soil, and F and H horizon of the pine forest soil. However, the number of soil microorganisms decreases with the depth in each forest soil. 3) The population of soil microbes is related to moisture content, total nitrogen, available phosphorus, and exchangeable calcium, except organic carbon in fungi. 4) The soil organic matter has been mainly decomposed by fungi, and the size of its population are governed by the factors such as moisture content, organic carbon, total nitrogen, available phosphorus, and exchangeable calcium.

• Korea journal of population studies
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• v.8 no.2
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• pp.11-29
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• 1985

This study describes the effects of demographic transition on the environmental changes in Korea. The basic framework of this study is a path model. This study analyzes the effects of population growth, urbanization and industrialization on the environmental deterioration. In doing this, this study illustrates the changing patterns of population growth, urbanization and industrialization. This study also shows the changing patterns of environmental conditions, focusing on air pollution, water pollution and wastes. Finally, this study deals with the consequences of the environmental deterioration, especially focusing on the changing quality of life in Korea.

• The Korean Journal of Food And Nutrition
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• v.9 no.3
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• pp.289-293
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• 1996

Population changes of aerobic bacteria and lactic acid bacteria and changes of pH, acidity, and total sugar content were creased from initial period of fermentation. Lactic acid bacteria Increased during the first one nay rapidly and thereafter they creased slowly thereafter. Acidity increased on the third day of fermentation. Acidity was very low In Kimchi containing both Total sugar content decreased gradually from initial period to late period of fermentation.