• Environmental and Resource Economics Review
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• v.4 no.2
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• pp.307-344
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• 1995

이 논문은 산업공해의 발생 요인을 규명하는 부분과 여기서 규명된 요인에 따라 배출량을 규제하고 그 규제효과를 추정하는 두 가지 부분으로 이루어져 있다. 이 논문에서는 환경(環境) 산업연관(産業聯關) 분석(分析) 모형(模型)을 이용하여 우리 나라의 산업(産業) 공해(公害) 배출(排出) 요인(要因)을 규명하고자 하였다. 이 분석의 결과 얻은 잠정적 결론은 첫째, 우리 나라는 지난 10년간 에너지 절약적(節約的)인 기술개발(技術開發)등 에너지의 효율성과 생산기술(生産技術)(투입구조(投入構造))의 개선 등 생산기술측면에서는 대기오염 배출량을 감소시키는 구조적 변화가 있었던 반면에, 수출입(輸出入) 구조(構造)등 수요 측면에서는 그 배출량을 증가시키는 구조적 변화가 발생하였다. 그러나 전체적으로 구조적 요인은 공해 배출량을 증가시키지 않은 반면 경제 성장에 따른 생산 규모의 확대로 총 배출량은 크게 증가하였다. 산업공해의 배출량을 감축시키기 위한 한 가지 정책수단(政策手段)으로 우리는 일정 율의 탄산까스 배출량(排出量)을 규제하기 위해 필요한 공해 제거 비용을 계산하고 배출 단위 제거비용을 Pigou적 공해조세(公害租稅)로 제시함으로서 일정 배출량 감축 효과를 가지는 공해세를 계산하고자 시도하였다. 이 같은 배출 규제(規制)에 의한 물가상승(物價上昇)의 파급정도(波及程度)는 각 산업의 공해제거(公害除去)를 위한 중간투입물(中間投入物) 수요(需要)와 규제대상(規制對象) 산업(産業)과의 산업연관(産業聯關) 정도(程度)에 따라 상이하다. 배출량(排出量)이 큰 6대(大) 공해산업(公害産業)에 대한 규제(規制)는 자기(自己) 가격상승율(價格上昇率)이외에 산업연관효과(産業聯關效果)의 차이 때문에 산업별로 다른 물가 파급효과를 발생시킨다는 것을 보였다. 특히 석유와 석탄 등의 에너지에 대한 탄산까스 배출 규제는 규제 산업의 자기 가격을 매우 높은 율로 상승시키며, 각각 화학, 고무, 섬유, 의복 제품과 1 차금속, 전력 가스, 조립금속, 시멘트 등에 높은 물가 파급효과를 나타내므로서 이산화탄소의 배출 규제 내지 탄소세의 부과가 몇 몇 산업의 가격 경쟁력에 집중적인 영향을 줄 것임을 시사하고 있다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.9
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• pp.82-87
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• 2008

Faster, safer and cheaper mailing of the postal matter is essential for surviving in the competitive market of home-delivery service. In the past, the domestic delivery business has been nu by only a few number of companies. But more and more number of companies including medium size ones are participating in the business, and the competition is getting severe. This paper proposes a method to select the optimal location of mail distribution centers that minimally connect the local mail centers of some major cities in Korea using the Steiner Tree theory, which is about connecting a finite number of points with a minimal length of paths and has been used in the distribution system optimization and optimal routing of the transmission lines of the electric power system. By using Steiner Tree theory in finding the best location of the postal delivery hub, we may expect the reduction of transportation cost and the increase of profit, resulting in acquiring the superior position in the competitive delivery business. It is expected that we may use the Steiner Tree theory in finding the best location of the electric power substation for the nott higher EHV(extreme high voltage) transmission network.

• Journal of the Korea Society for Simulation
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• v.25 no.3
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• pp.1-14
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• 2016

This paper proposes four general wireless gateway types, which are distinguished by their own processing ways to connect between a wireless sub-network of things and the mobile internet that links mobile network to internet step by step. In this paper, we also design general processing procedures of these four types using the state transition model. Gateways of each types were developed on the basis of the resulted state transition models and their performances were evaluated through several tests, analyzed, and compared each other. As the results of our evaluation, compared with the other types, the type, which combines both of a low-power Sleep-interrupt way and polling ways for receiving data or responses in all the waiting states of a gateway, shows the best performance in all of data transmission real-timeliness, data loss and energy consumption.

• Journal of the Korea Society of Computer and Information
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• v.17 no.2
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• pp.13-21
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• 2012

Mobile data caching is usually used as an effective way to improve the speed of local transaction processing and reduce server load. In mobile database environment, due to its characters - low bandwidth, excessive latency and intermittent network, caching is especially crucial. A lot of mobile data caching strategies have been proposed to handle these problems over the last few years. However, with smart phone widely application these approaches cannot support vast data requirements efficiently. In this paper, to make full use of cache data, lower wireless transmission quantity and raise transaction success rate, we design a new mobile data caching synchronization strategy based on in-demand and replacement priority. We experimentally verify that our techniques significantly reduce quantity of wireless transmission and improve transaction success rate, especially when mobile client request a large amount of data.

• Journal of Environmental Science International
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• v.28 no.2
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• pp.169-182
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• 2019

Temporal and spatial variations in surface ozone concentrations in Busan were investigated by using observation data from urban air quality sites during 2001-2016. The annual ozone concentrations showed a significant increasing trend of $+0.40ppb\;yr^{-1}$ in this period, with a more rapid increase of $+0.81ppb\;yr-1$ since 2010. For the monthly analysis, the increase in ozone concentration was the greatest in August ($+0.68ppb\;yr-1$). These ozone trends were due mainly to rising temperature ($+0.05^{\circ}C\;yr^{-1}$) and weak decreasing precipitation ($-6.42mm\;yr^{-1}$). However, the extreme weather events (heat wave, localized heavy rain, etc.) lead to an increase in short-term variability of ozone since 2010. The relatively low ozone concentrations in the downtown area were caused by high NOx emissions from mobile sources. The increases in ozone concentrations were observed at most of the air quality monitoring sites due to the reductions in anthropogenic emissions of NOx during 2001-2015. However, in the southern coastal area, lower rates of increase in ozone concentrations were observed by $-0.10{\sim}0.25ppb\;yr^{-1}$ due to the significant NOx emitted by ships in the Busan port and Busan new port.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.4
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• pp.498-503
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• 2019

Electric propulsion ships are gaining widespread interest in the marine industry owing to extreme air pollution concerns. Consequently, several studies are actively being conducted for improving the power quality. Various methods have been developed that incorporate passive filters, notch filters, and active filters for reducing the harmonic content in the input current of a conventional diode front end rectifier. Among such filters, the active front end (AFE) rectifier is considered as an excellent technology. In this paper, current control for an AFE rectifier employing space vector PWM (Pulse Width Modulation) is proposed. Conventional current control methods for the AFE rectifier, hysteresis, SPWM (Sinusoidal Pulse Width Modulation), and SVPWM (Space Vector Pulse Width Modulation) were simulated by employing the PSIM software tool for analysis and comparisons. The results corroborate that SVPWM has the simplest structure and provides the best performance.

• Journal of Platform Technology
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• v.9 no.4
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• pp.79-89
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• 2021

In this paper, the fine dust (PM10) and ultrafine dust (PM2.5) measurement platforms are designed to be mobile and fixed using oneM2M, the international standard for IoT. The fine dust measurement platform is composed and designed with a fine dust measurement device, agent, oneM2M platform, oneM2M IPE, and monitoring system. The main difference between mobile and fixed is that the mobile uses the MQTT protocol for interconnection between devices and services without blind spots based on LTE connection, and the fixed uses the LoRaWAN protocol with low power and wide communication range. Not only fine dust, but also temperature, humidity, atmospheric pressure, volatile organic compounds (VOC), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), and noise data related to daily life were collected. The collected sensor values were managed using the common API provided by oneM2M through the agent and oneM2M IPE, and it was designed into four resource types: AE and container. Six functions of operability, flexibility, convenience, safety, reusability, and scalability were analyzed through the fine dust measurement platform design.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.103-110
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• 2022

Ultrafine Particle number and size distributions were simultaneously measured at rural area around the power plant in Dangjin, South Korea. New Particle formation and growth events were frequently observed during January, 2021 and classified based on their strength and persistence as well as the variation in geometric mean diameter(GMD) on January 12, 21 and 17. In this study, we investigated mechanisms of new particle growth based on measurements using a high resolution time of flight aerosol mass spectrometer(HR-ToF-AMS) and a scanning mobility particle sizer(SMPS). On Event days(Jan 12 and 21), the total average growth rate was found to be 8.46 nm/h~24.76 nm/hr. These growth rate are comparable to those reported for other urban and rural sites in South Korea using different method. Comparing to the Non-Event day(Jan 17), New Particle Growth mostly occurred when solar radiation is peaked and relative humidity is low in daytime, moreover enhanced under the condition of higher precusors, NO₂ (39.9 vs 6.2ppb), VOCs(129.5 vs 84.6ppb), NH₃(11 vs 4.7ppb). The HR-ToF-AMS PM_1.0 composition shows Organic and Ammoniated nitrate were dominant species effected by emission source in domestic. On the other hand, The Fraction of Ammoniated sulfate was calculated to be approximately 16% and 31% when air quality is inflow from China. Longer term studies are needed to help resolve the relative contributions of each precusor species on new particle growth characteristics.

• Korean Journal of Optics and Photonics
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• v.33 no.3
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• pp.99-105
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• 2022

We have evaluated the performance of an all-optical automatic gain-controlled (AGC) erbium-doped fiber amplifier (EDFA) to suppress the optical signal fluctuation induced by atmospheric turbulence in terrestrial free-space optical communication systems. In our measurements, the input power into the EDFA was set to be -30 dBm and -10 dBm to operate the amplifier in the small-signal and saturation regions, respectively. The fluctuations in the optical signal were emulated with an acousto-optic modulator driven with a sinusoidal voltage. From the measured results, we have found that an all-optical AGC EDFA could suppress the optical signal fluctuation effectively, as long as the EDFA operated in the small-signal region with a high feedback amplified spontaneous emission (ASE) power.

• Applied Chemistry for Engineering
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• v.35 no.2
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• pp.128-133
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• 2024

Although antisolvent-assisted crystallization is one of the promising processes to produce high-quality perovskite films, general antisolvents such as chlorobenzene (CB) have toxic and volatile properties. In addition, CB is not suitable to control the crystallization of perovskite in the atmospheric air. In this work, isopropyl acetate (IA) is used as an eco-friendly antisolvent to demonstrate air-processed perovskite solar cells, and ethyl-4-cyanocinnamate (E4CN) with a cyano group, carbonyl group, and aromatic ring is introduced in IA to improve the performance and stability of devices. Defects at the surface and grain boundaries of the perovskite layer, such as un-coordinated Pb²⁺ and iodine, can be decreased resulting from the interaction of E4CN and perovskite, and thus reduced recombination and enhanced carrier transport can be expected. As a result, the perovskite device with E4CN achieves a high maximum power conversion efficiency (PCE) of 18.89% and outstanding stability, maintaining 60% of the initial efficiency for 300 h in the air without any encapsulation.