• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.3 no.1
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• pp.23-31
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• 1999

An advanced mobile technology is described for saturating water with oxygen. The MTR(Mass Transfer Reactor) is 2~10 times more effective in dissolving oxygen in water compared to most other systems used in aquaculture, because it can generate extremely small(0.005~0.05mm) bubbles. New fish farming facilities could make use of this technology to build deeper ponds for raising multiple species with optimized conditions for DO(dissolved oxygen), food, light, etc. The proposed technology offers higher DO levels with minimal operating costs. It is easy to use and maintain, with a high reproducibility. Accordingly, the MTR can be industrially applied in the treatment of fish waste and reduction of water consumption during fish farming.

• ETRI Journal
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• v.43 no.2
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• pp.173-183
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• 2021

As low-power wide-area network (LPWAN) end devices (EDs) are deployed in massive scale, their economic and environmental costs of operation are becoming too significant to ignore and too difficult to estimate. While LPWAN architectures and protocols are designed to primarily save energy, this study shows that energy saving does not necessarily lead to lower cost or environmental footprint of the network. Accordingly, a theoretical framework is proposed to estimate the operational expenditure (OpEx) and environmental footprint of LPWAN EDs. An extended constrained optimization model is provided for the ED link assignment to gateways (GWs) based on heterogeneous ED configurations and hardware specifications. Based on the models, a simulation framework is developed which demonstrates that OpEx, energy consumption, and environmental footprint can be in conflict with each other as constrained optimization objectives. We demonstrate different ways to achieve compromises in each dimension for overall improved network performance.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.3
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• pp.145-158
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• 2015

Disposable marine product packaging materials such as wooden, Styrofoam, and corrugated cardboard boxes have a very low reuse rate, thus causing the logistics costs to rise and making it difficult to establish a unit load system for marine products. Disposable packing containers to be discarded are accompanied by resource and environmental issues home and abroad. Transportation vehicles for marine products have to return empty without loading different kinds of products after delivery due to the smell and properties of marine products, thus posing as an obstacle to logistics rationalization. In an effort to overcome those limitations, this study examined the stages of transportation including "producer-wholesale market in the producing area-commission merchant-wholesale market in the consumption area-commission merchant-quasi-wholesale market-consumer" and also analyzed the utilization and distribution of disposable packaging materials currently used in the circulation of marine products including wooden, Styrofoam, and corrugated cardboard boxes. Based on the analysis results, the investigator developed a logistics rationalization model capable of promoting semi-permanent reuse and lowering empty vehicle rate on return routes as an alternative to address environmental issues caused by disposable packaging materials, which have been an obstacle to the logistics rationalization of marine products, packaging costs in the process of repeating packing and unpacking at each stage of marine products circulation, and empty vehicle rates on return routes after marine products delivery.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.4
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• pp.522-533
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• 2012

This paper presents an adaptive strategy of GENCOs for reducing the greenhouse gas by fuel mix change. Fuel mix stands for generation capacity portfolio composed of different fuel resources. Currently, the generation sector of power industry in Korea is heavily dependent on fossil fuels, therefore it is required to change the fuel mix gradually into more eco-friendly way based on renewable energies. The generation costs of renewable energies are still expensive compared to fossil fueled resources. This is why the adaptive change is more preferred at current stage and this paper proposes an optimal strategy for capacity planning based on multiple environmental scenarios on the time horizon. This study used the computer program tool named GATE-PRO (Generation And Transmission Expansion PROgram), which is a mixed-integer non-linear program developed by Hongik university and Korea Energy Economics Institute. The simulations have been carried out with the priority allocation method in the program to determine the optimal mix of NRE(New Renewable Energy). Through this process, the result proposes an economic fuel mix under emission constraints compatible with the greenhouse gas mitigation policy of the United Nations.

• Applied Chemistry for Engineering
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• v.29 no.1
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• pp.1-9
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• 2018

Microalgae is considered as one of environmentally sustainable and potential feedstocks to produce biodiesels. However, recent studies on life cycle assessments (LCA) of microalgal buidiesels have shown that energy requirement is not small to produce biodiesel from microalgae, especially during cultivation stage. The costs for carbon sources, nutrients like nitrogen or phosphorous, and water for cultivation can contribute up to 80% of the total medium costs. In the present article, recent trends on the utilization of several promising nutrient sources such as municipal wastewaters, organic fertilizers, combustion exhaust emissions and organic solid wastes were reviewed, and the potential strategies to be used as substitutes of artificial culture media, especially for the biodiesel production, were discussed.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.6
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• pp.29-37
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• 2014

The objective of this study is to estimate the cost and benefits of street trees for their planting types, specifically, single row, single row+bottom, double row, double row+bottom. Different planting types are compared and analyzed by using Net Present Value (NPV) and benefit-cost ratio (BCR). Existing data are collected from the literature reviews for the use of meta-analysis method for estimating cost and benefit. The elements for analyzing costs are management and planting costs, and benefits are air purification, energy saving and landscape view. The discount rate is applied at a minimum of 3% and a maximum of 5.5%. The unit used in this calculation is km/year. The result shows that the net benefit is highest in double row, followed by single row, double row+bottom, and single row+bottom. The BCR is the highest in double row, followed by single row, double row+bottom, and single row+bottom. The BCR reaches the break-even point from 9 to 17 years depending on the planting types.

• Journal of Navigation and Port Research
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• v.36 no.9
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• pp.741-751
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• 2012

This article analyzes the interdependency between nonrenewable marine sand resources and renewable fishery resources by the developed dynamic bioeconomic model. The developed bioeconomic model is applied to a case study of efficient sustainable management for marine sand mining, which adversely affects a valuable blue crab fishery and its habitat in Korea. The socially-efficient extraction plan for marine sand and the time-variant environmental external costs to society in terms of diminished harvest rate of blue crab are determined. To take into account long-term effects from destroyed fishery habitat, a Beverton-Holt age structure model is integrated into the bioeconomic model. The illustrative results reveal that the efficient sand extraction plan is dynamically constrained by the stock size of the blue crab fishery over time. Thus, the dynamic environmental external cost is more realistic resource policy option than the classical fixed external cost for determining socially optimal extraction plans. Additionally, the economic value of bottom habitat, which supports the on- and off-site commercial blue crab fishery is estimated. The empirical results are interpreted with emphasis on guidelines for management policy for marine sand mining.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.641-649
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• 2020

The study examines the effect of environmental factors on the international harmonization process of accounting on small and medium enterprises in Vietnam. These factors include legal environment, business environment, and cultural environment. The data is collected by a survey of 100 accountants and 100 auditors on the factors that affects the international harmonization process of accounting. The T-Tests indicate differences between the answers of the accountants and auditors. First, for the accountants, legal environment has the biggest effect on the harmonization process of accounting; while on the auditors, business environment has the biggest influence. Second, while the accountants consider costs higher than benefits in the harmonization process of accounting, the auditors assume that benefits are superior to costs that businesses spend. Third, both the accountants and the auditors indicate that the harmonization process of accounting should not be applied for all small and medium enterprises. From the study results, the author has given a different evaluation method that Vietnam should implement for international harmonization with the required adjustments as per the suitability with the status of businesses in Vietnam. The process of harmonization in accounting practices should not be indiscriminately applied to all the small and medium enterprises either.

• Journal of the Korean Ceramic Society
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• v.43 no.10 s.293
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• pp.626-634
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• 2006

Ceramics manufacturers in the nation produced more than 5000 tons of ceramics wastes a year increasing industrial waste quantity: However, almost no researches were made to reduce environmental pollution and to recycle waste ware. In this study, white ware scraps that were produced at Icheon, Gyeonggi-do were recycled to make use of them as raw materials of ceramics body and to develop new ceramics body that had economic advantages and good quality. The findings showed that the addition of waste ware had limit of 20 wt% considering molding. The addition of waste ware of 20 wt% to white ware lowered baking temperature of the white ware that was added by waste ware of 20 wt% by 30$^{\circ}C$ than existing white ware, and property values were good, for instance, porosity of 3% in average and water absorptivity of 2% in average, and the bending strength recorded more than 800 kgf/$cm^2$ to be high than that of existing white ware being sold in market. The waste ware could be used to produce new ware body and to recycle resources and to solve environmental problems caused by burial and to improve property of ceramics and to save transportation costs as well as baking costs.

• Korean Institute of Interior Design Journal
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• v.15 no.2 s.55
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• pp.174-182
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• 2006

This study is focused on interior materials and wastes among other diverse environmental strategies for sustainable construction. The case study was carried out by using MSDG, mainly utilized in evaluating performance of sustainable constructions in Minnesota, the US, as an evaluation tool, in order to analyze American practices. In this study, a field inspection was conducted to 6 Minnesota cases, following a preliminary examination through literature study and portal site search, and then, constructive reports, interviews with people in charge, and empirical data including photos were added to the basic data provided by MSDG and MOEA As a result, it turned out *that sustainable materials were mainly used even in newly constructed buildings and wastes were properly managed in an environment-friendly, economical, and ethical manner, *that life cycle assessment showed reduction in some constructive costs even when the basic costs were high, *that some recycled finish materials were widely used in diverse areas, *that minimum consumption of raw materials, minimum environmental damage by materials, minimum effect of materials on IAQ were found in the examined cases, and *that many attempts were made to minimize resource consumption and constructive wastes from diverse perspectives.