• Journal of Environmental Science International
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• v.29 no.6
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• pp.623-631
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• 2020

This study analyzes the effect of negative air ions on the concentration of airborne particulate matter and evaluates the expected purification efficiency of open spaces for particulate matter by investigating the amount of negative air ions generated by plants. This study establishes a negative air ion generation treatment environment, plant environment, and control environment to measure the purification efficiency of particulate matter under the conditions of each, analyzing the expected purification efficiency by designing a particulate matter purification model. Results show that the amount of generated negative air ion according to environment was negative air ion generation treatment environment > plant environment > control environment; this order also applies to the particulate matter purification efficiency. Moreover, it took 65 min for the negative ion generation treatment environment, 90 min for the plant environment, and 240 min for the control environment to reach the standard expected purification efficiency of particulate matter concentration of 960 mg/㎥ for PM₁₀. For PM_2.5, with the designated maximum concentration of 700 mg/㎥, it took 60 min for the negative ion generation treatment environment, 80 min for the plant environment, and more than 240 min for the control environment. Based on these results, the expected purification efficiency compared to the control environment was quadrupled in the negative ion generation treatment environment and tripled in the plant environment on average.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.581-591
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• 2014

This study analyze the policy efficiency of the environment-friendly farming zone program using data envelopment analysis. On analyzed results, the average policy efficiency is 0.185 and 98.3% of zones are inefficient. 97.8% of zones are in increasing returns to scales. The empirical results indicate that more work need to be done to increase the efficiency of the program.

• Korean Journal of Organic Agriculture
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• v.24 no.3
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• pp.337-353
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• 2016

The objective of this study is to analyze the DEA efficiency of the environment-friendly agricultural districts and zones. There are political inefficiency in districts and zones with 45.3% and 85.0%. It mainly results from scale efficiency than pure technical efficiency. There are 10 efficient zones, while 34 decreasing return to scale ones. Meanwhile, districts mostly have increasing return to scale with 97.9%. The results of this study is meaningful to re-construct the project based on the environment-friendly agricultural production.

• Environmental and Resource Economics Review
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• v.22 no.2
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• pp.329-365
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• 2013

The purpose of this paper is to measure economy and environment efficiencies under fossil fuel and environment regulation by countries for 2000-2009. Distinguishing 83 countries with three groups of OECD, upper-middle, and low countries, we compare four models such as environment oriented, economy-oriented, environment-economy oriented, and two-stage types, which include a desirable output, GDP and an undesirable output, pollutant together in the production possibility set. OECD countries relatively showed high economy efficiency and low environment efficiency, whereas Non-OECD countries showed high environment efficiency and low economy efficiency. OECD countries reported a higher possibility to reduce fossil fuel and $CO_2$ emission.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.2
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• pp.85-95
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• 2019

The internal environment in pig house is closely related to the animal productivity. In addition, it is important to consider a working environment inside the pig house due to high gas and dust concentrations. The poor working environment inside the pig house can cause health problems including respiratory diseases. To analyze the working environment, it is important to evaluate the ventilation efficiency to effectively remove harmful gases and dust. The purpose of this study is to develop a 3D CFD model to analyze the working environment in the pig house. CFD model was validated by comparing air temperature distributions between CFD computed and field measured data. The average air flow rate at the pig height was 40.1 % lower than the working height when incoming air was concentrated on upper layer by the installed ventilation system on the experimental pig house. Using the validated CFD model, the regional ventilation efficiency was computed by the TGD(tracer gas decay) method at the pig and working heights. There was a difference of ventilation efficiency on 14 % between the air stagnated section and the rest sections. Stagnated gas concentration can be effected by animal and human health.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.3
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• pp.236-241
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• 1993

Recently, with the ourdoor air pollution, the indoor air pollution devided into living environment and working environment are raised as the problem of indoor space. Also, the more time lived in indoor space, the larger the influence of indoor air pollution. Therefore in this study, the spatial variation of ventilation efficiency was estimated through the experiment using a physical model. The experiment using a physical model. The experiment was conducted in two category; the central zone of ventilated air flow and the corner zone. As the result of experiment, high ventilation efficiency (90$\sim$108%) was shown in the central zone of ventilated air flow. Whereas low ventilation efficiency (46$\sim$77%) was shown in the corner zone. In conclusion, when the designing of ventilation was planned, the zone showed low ventilation efficiency should be considered.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.07a
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• pp.243-246
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• 2012

A new multi inner stage(MIS) cyclone was designed to remove the acidic gas and minute particles of harmful materials produced from electronic industry. To characterize gas flow in MIS cyclone, pressure and velocity distribution were calculated by means of computational fluid dynamics(CFD) commercial program. Also, the flow locus of particles and particle removal efficiency were analyzed by Lagrangian method. When outlet pressure condition was -1,000 Pa, the efficiency was the best in this study. Based on the CFD simulation result, the pressure loss and destruction removal efficiency was measured through MIS cyclone experiment.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.2
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• pp.163-170
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• 2013

The fine-particles, moisture and variety of hazardous gases are produced during electronic manufacture process. Most of the fine-particles are 0.1~10 ${\mu}m$ in size and the hazardous gases such as HF, $SiH_4$, CO, $NH_3$, etc. seriously affect environment, human's body and manufacturing process. To remove these characterized gases and fine-particles, Water-Cyclone designed and tested for removal efficiency on fine-particles and $NH_3$ under -980Pa negative pressure condition. As a result, under 0.1~1.0 $m^3/min$ flow condition, the efficiency on 5 ${\mu}m$ particles was 80~96%, 10 ${\mu}m$ particles was 86~96%, and 20 ${\mu}m$ particles was 91~99%. Besides, the removal efficiency on soluble gas $NH_3$ was 56.5% at 0.5m3/min and 79.1% at 1.0m3/min under 500 ppm flow concentration and 70.0% at 1.0 $m^3/min$ under 1,000 ppm flow concentration. Therefore, on particles, as the flow rate and particle size increased, the collection efficiency rate was increased. On soluble gas, as the flow rate increased, the removal efficiency was increased under the same concentration.

• Journal of Microbiology and Biotechnology
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• v.22 no.9
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• pp.1288-1295
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• 2012

Exposure to bioaerosols causes various adverse health effects including infectious and respiratory diseases, and hypersensitivity. Controlling exposure to bioaerosols is important for disease control and prevention. In this study, we evaluated the efficacies of various functional filters coated with antimicrobial chemicals in deactivating representative microorganisms on filters or as bioaerosols. Tested functional filters were coated with different chemicals that included (i) Ginkgo and sumac, (ii) Ag-apatite and guanidine phosphate, (iii) $SiO_2$, ZnO, and $Al_2O_3$, and (iv) zeolite. To evaluate the filters, we used a model ventilation system (1) to evaluate the removal efficiency of bacteria (Escherichia coli and Legionella pneumophila), bacterial spores (Bacillus subtilis spore), and viruses (MS2 bacteriophage) on various functional filters, and (2) to characterize the removal efficiency of these bioaerosols. All experiments were performed at a constant temperature of $25^{\circ}C$ and humidity of 50%. Most bacteria (excluding B. subtilis) rapidly decreased on the functional filter. Therefore, we confirmed that functional filters have antimicrobial effects. Additionally, we evaluated the removal efficiency of various bioaerosols by these filters. We used a six-jet collision nebulizer to generate microbial aerosols and introduced it into the environmental chamber. We then measured the removal efficiency of functional filters with and without a medium-efficiency filter. Most bioaerosol concentrations did not significantly decrease by the functional filter only but decreased by a combination of functional and medium-efficiency filter. In conclusion, functional filters could facilitate biological removal of various bioaerosols, but physical removal of these by functional was minimal. Proper use of chemical-coated filter materials could reduce exposure to these agents.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.3
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• pp.227-232
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• 2010

In this paper we consider the multi-robot system that collects target objects spread in an unexplored environment. The robots cooperate each other to improve the capability and the efficiency. The robots attract or intimidate each other as behaviors of bacterial swarms or particles with electrical moments. The interactions would increase the working efficiency in some environments but it would decrease the efficiency in some other environments. Therefore, the system needs to adapt to the working environment by adjusting the strengths of the interactions. The strengths of the interactions are expressed as sets of gene codes that mean the weights of each kind of attracting or intimidating vectors. The proposed system adjusts the gene codes using evolutional strategy. The proposed approach has been validated by computer simulation. The results of this paper show that our inter-swarm interacting strategy and optimizing algorithm improves the working efficiency, adaptively to the characteristics of environments.