• 한국대기환경학회지
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• 제31권5호
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• pp.461-471
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• 2015

Base on emission factors derived from National Institute of Environmental Research, Particulate matter from combined cycle power plants (CCPPs) has been estimated to be a important source of $PM_{10}$. Generally there is no serious emission of particulate matter in CCPPs. because the fuel of them is natural gas. But emission gas after long shut down season has very high dust content. Therefore $PM_{10}$ emission rate is dependent on its operation mode. In this study, particulate dispersion study for new city near CCPPs complex has performed using CALPUFF model for three case. $PM_{10}$ concentration has big difference between normal operation and 2 case start-up condition after long shutdown. In normal operating conditions, daily $0.32{\sim}0.50{\mu}g/m^3$ influence on of the surrounding area. But when 1~2 aerobic high concentration discharged conditions, average concentration is higher about $9.2{\sim}34.1{\mu}g/m^3$ than normal operating conditions.

• 한국물환경학회지
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• 제26권4호
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• pp.585-589
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• 2010

In order to evaluate the performance of a powdered activated carbon (PAC) contactor, two water treatment plants (WTP) were selected as target sites. The result of tracer tests showed that the plug flow portion of a bisymmetry-type contactor (H WTP) was more than 70%. A maze-type contactor (C WTP) also had more than 70% of plug flow portion after intra-basin baffles were installed. According to the operating data of the target WTPs, there was no clear evidence that the addition of PAC contributed to the removal of organics. However, the results of jar tests, conducted with the raw water taken from the H WTP, proved that PAC could remove dissolved organic carbon (DOC) to some extent when the proper velocity gradient was maintained. It was estimated that the production rate, defined as the ratio of the operating flowrate to the design flowrate, of the C and H WTPs was only 27 and 50%, respectively. Because of these lower production rates, the mixing intensity in the contactor was much less than the designed value and, finally, the performance of the PAC contactor was much lower than what was expected.

• 한국대기환경학회지
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• 제14권5호
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• pp.443-454
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• 1998

Pt-V catalytic converter was installed on a heavy duty diesel engine and the characteristics of the emission reduction were tested using a engine dynamometer at various operating conditions. The emission reduction performance of Pt-V catalyst was also compared with that of a commercialized Pt catalyst currently being used in some of the heavy duty diesel engines in advanced countries. The effects of Pt-V and Pt catalysts on regulated and unregulated emissions were investigated using a 0.05 weight percent sulfur content fuel with an engine dynamometer Experiments for gaseous emissions (CO, HC and aldehyde) as well as particulate emissions (TPM, SOF and sulfate) have been conducted at several operating conditions such as T-7 mode, D-13 mode and S-13 mode before and after installing the Pt-V and Pt catalysts in the exhaust system. The emission reduction performance of Pt catalyst with respect to CO, HC, SOF, PAHs and aldehyde was found to be a little higher than that of Pt-V catalyst, but the Pt catalyst showed innate disadvantage of causing an increase of PM due to the sulfate formation via high SO2 conversion at high exhaust temperature, especially above 45$0^{\circ}C$.

• 한국물환경학회지
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• 제23권5호
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• pp.761-765
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• 2007

The study were conducted in order to investigate the effect of operating parameters including the internal recycle (nitrification return) rates, hydraulic retention times (HRTs) and temperature when using a cilium media method. The first experiment was for evaluating the effect of HRT (12 hr, 10 hr, 8 hr, 6 hr, 4 hr). The second experiment was for analyzing effect of internal recycle rate (100%, 200%, 300%, 400%). As a result of the first experiment, BOD was removed to 97~98% for 6~8 hr HRT. Effluent water quality was not significantly influenced with HRT within that range. However the nitrogen removal was sensitive to HRT. T-P removal efficiency was invariable at various HRTs. The average BOD removal efficiency was about 97% in spite of change of internal recycle rate while T-N removal efficiency was increased at the internal recycle rate of 100~200%, but invariable at the internal recycle rate of 200~300%.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1594-1597
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• 2005

A rapid development and a wide use of the Internet have expanded a network environment. Further, the network environment has become more complex due to a simple and convenient network connection and various services of the Internet. However, the Internet has been constantly exposed to the danger of various network attacks such as a virus, a hacking, a system intrusion, a system manager authority acquisition, an intrusion cover-up and the like. As a result, a network security technology such as a virus vaccine, a firewall, an integrated security management, an intrusion detection system, and the like are required in order to handle the security problems of Internet. Accordingly, a router, which is a key component of the Internet, controls a data packet flow in a network and determines an optimal path thereof so as to reach an appropriate destination. An error of the router or an attack against the router can damage an entire network. This paper relates to a method for RSMS (router security management system) for secure networking based on a security policy. Security router provides functions of a packet filtering, an authentication, an access control, an intrusion analysis and an audit trail in a kernel region. Security policy has the definition of security function against a network intrusion.

• 한국지하수토양환경학회지:지하수토양환경
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• 제16권3호
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• pp.10-16
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• 2011

The experimental studies for remediation of diesel contaminated soils were performed using subcritical water in laboratory scale. Contaminated soils from industrial area and artificially contaminated soils were utilized for soil remediation. Experimental system was composed for subcritical water to flow upward through the soil packed column for extracting contaminants. 10 g of contaminated soil was packed into the column and water flow rate was 2 mL/min. To evaluate the effects of temperature, pressure and treatment time on the removal efficiency, temperature was changed from 100$^{\circ}C$ to 350$^{\circ}C$, pressure from 50 bar to 220 bar and treatment time at the predetermined temperature from 0 min to 120 min. The purification efficiency increased as temperature increased. However, the effect of pressure and treatment time was low. Temperature 250$^{\circ}C$, pressure 50 bar and treatment time 30 min were selected for optimal operating condition for this study.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.201-205
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• 1997

As manufacturing system have become complex and globalized, rapid development and production of products are essentially requisites for competitiveness. The importance of agility in manufacturing is being emphasized and a new paradigm is necessary for reduction of the time and expenses related to planning, product development and production. To meet such requirements, virtual manufacturing (VM) environment was suggested. In this paper, Multi-agent system is adopted into VM operating system. Because our system is flexible due to agent technology, agents can be added or deleted with ease. VM unit modules which were defined as DEVS models execute independent simulation of other modules in unit level and compose one VM system with other modules. They also execute simulation in system level. This research can contribute to usefulness of VM environment due to flexibility and extensibility of this system.

• 한국대기환경학회지
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• 제22권2호
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• pp.223-233
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• 2006

We analyzed the monthly and seasonal mean of the daily Erythemal Ultraviolet-B (EUV-B, $280{\sim}320nm$) irradiance operating in Pohang, Anmyeon, Gosan, Mokpo and Kangnung with UV-Biometer (Solar Light Co., Model No. 501) at clear-sky noon during the period from 1999 to 2004. Also, we investigated the seasonal and regional characteristics for the UV index over the Korean Peninsula. The daily maximum occurred near solar southing time and the highest monthly accumulated EUV-B irradiance appeared in July and August at each regional observatory. The monthly mean value of the clear-sky EUV-B irradiance in Pohang, Anmyeon, Gosan, Mokpo and Kangnung showed 196.6, 161.8, 221.9, $171.5mWm^{-2}\;and\;179.7mWm^{-2}$ near noon in July respectively. The annual mean value of the daily accumulated EUV-B irradiance in Pohang, Anmyeon, Gosan, Mokpo and Kangnung were 1.8, 2.1, 2.2, $1.8kJm^{-2}\;and\;1.5kJm^{-2}$ respectively. The UV Index (UVI) showed above UVI 7(High) more than 90 days during one year over the Korean Peninsula.

• 해양환경안전학회지
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• 제11권1호
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• pp.83-88
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• 2005

이 연구에서는 낙도보조항로의 운영실태와 발달과정에 대하여 정리하였다. 낙도보조항로는 14개 사업자가 U개 항로에서 총 30척 선박으로 낙도주민을 위한 안정적인 생활교통편의를 제공하고 있다. 항로별 수송실적을 분석한 결과, 낙도보조 항로를 이용하는 여객 수가 매년 증가하고 있다. 선박 이용자의 서비스 만족도를 향상시키기 위해서 운영사업체별로 경영평가제를 도입하는 등 보다 구조적인 변화가 요구된다. 이 연구의 결과들은 낙도보조항로 중장기 발전방향 수립에 기초 자료로 활용하는 데 그 의미가 있다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1213-1219
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• 2008

This experimental study was to analyze thermal comfort and indoor air quality(IAQ) with ventilation and humidification in the classroom when system air conditioner was operated. The thermal comfort was estimated by the PMV index and the concentration of $CO_2$ and total suspended particle(TSP) were measured and compared with ventilation and humidification. As a result, the class room temperature distribution was $2{\sim}5^{\circ}C$ low during operating ventilation system and humidification. At 60% RH, PMV values of measuring points were ranged from +0.5 to -0.5 indicating optimal the range of thermal comfort. The average concentration of $CO_2$ gas and TSP were reduced 645 ppm, 0.17 mg/$m^3$ respectively, during operating the ventilation system. From the results, to maintain comfortable environment in the heated classroom, the ventilation and humidification were needed in winter season.