• 대기
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• 제34권3호
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• pp.283-304
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• 2024

This study analyzed the variability and correlation between ground-level air pollutant concentrations and the atmospheric mixing layer height using data from four types of air pollutants (PM_2.5, PM₁₀, NO₂, and O₃) collected at AirKorea monitoring stations nationwide over a five-year period (2018~2022), and aerosol backscatter data observed by the Vaisala CL31 to derive atmospheric mixing layer heights. The five-year trends and variability of ground-level air pollutant concentrations under seasonal and hourly conditions were examined, as well as the seasonal distribution and diurnal variation of the atmospheric mixing layer height. Five correlation coefficient methodologies were applied to analyze the correlations between ground-level air pollutants and atmospheric mixing layer height under various seasonal and hourly conditions, confirming the dilution effect of the atmospheric mixing layer height. The results showed that PM_2.5, PM₁₀, and NO₂ generally had negative correlations with the atmospheric mixing layer height, while O₃ showed a strong positive correlation up to an altitude of 1,200~1,500 meters, and a negative correlation beyond that altitude. It was also shown that a single high concentration event (e.g., PM₁₀) can alter the overall correlation. The correlation can also vary depending on the characteristics of the correlation coefficient methodology, highlighting the importance of applying the appropriate methodology for each case during the analysis process.

• 한국자동차공학회논문집
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• 제16권2호
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• pp.150-157
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• 2008

The main objective of this paper is to investigate the performance characteristics of a $CO_2$ air conditioning system for fuel cell electric vehicles (FCEV). The present air conditioning system for FCEV uses the electrically driven compressor and electrically controlled expansion valve for $CO_2$ as a working fluid. The experimental work has been done with various operating conditions, which are quite matching the actual vehicle's driving conditions such as different compressor speed and high pressure to identify the characteristics of the system. Experimental results show that the cooling capacity and coefficient of performance (COP) were up to 6.3kW and 2.5, respectively. This paper also deals with the development of optimum high pressure control algorithm for the transcritical $CO_2$ cycle to achieve the maximum COP.

• 한국태양에너지학회 논문집
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• 제32권5호
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• pp.11-17
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• 2012

In this study, a simulation program was developed with heat transfer model in the thermal storage tank for a solar collector and burner combined heating and hot water supply system. Analysis was conducted with variation of operating condition and schedule to analyze performance of a hot water supply and panel heating system with a solar collector and burner combined thermal storage tank. The simulation program is divided two sections. One part is calculation of temperature variation of water which flows through the panel in the floor for heating of the residential house during 24 hours, and the other part is heat transfer calculation for the reaction time to get desired water temperature in the thermal storage tank. As results, light oil consumption and system performance during operation period were analyzed with variation of climate condition and with or without solar collector. Most of the case, oil could be saved about from 24 to 41% with installing the solar collector. The performance of the system is more dependent on radiation time of the solar collector rather than the intensity of the solar radiation which was adopted for the climate analysis.

• 한국컴퓨터정보학회논문지
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• 제27권3호
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• pp.99-104
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• 2022

본 논문에서는 기후변화에 능동적으로 대처하여 빨래 감을 자동으로 제어하는 베란다용 스마트 빨래 건조 시스템을 처음으로 개발하고 소개하고자 한다. 개발된 스마트 빨래 건조 시스템은 앱을 통해 빨랫감 위치 정보를 받은 후, 위치 정보에 따른 온도, 습도 등의 기상청 데이터를 통해 기후 변화를 실시간으로 감지하여 비가 오는 상황이 발생할 경우 건조대 위에 빨래 감을 자동으로 제어한다. 아두이노 습도 센서와 기상청 Open-API 를 통해 기상 정보를 취득하고 이는 라즈베리파이가 스위치 봇을 제어하는데 이용된다. 사용자 인터페이스는 Blynk를 사용하였으며, 스위치 봇은 빨랫감을 제어한다. 제안 시스템은 기상 악화를 감지하고 원격지에 있는 빨래감을 자동으로 제어하여 비 피해를 예방해줄 수 있다.

• 전기전자학회논문지
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• 제26권1호
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• pp.56-61
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• 2022

전 세계적으로 에너지 사용량이 증가함에 따라 지구온난화와 같은 환경문제가 초래되었으며, 이에 각국은 협정·협약을 통한 에너지 산업의 탈탄소화와 함께 화석 에너지를 신재생에너지로 빠르게 전환 중이다. 발전량이 급변하는 신재생에너지 보급 확대에 따라 효율적인 에너지 관리의 필요성이 대두되는 한편, AI 기술이 발전함에 따라 에너지 관리 분야와 결합한 AI 기반 빌딩 에너지 관리 시스템(Building Energy Management System, BEMS)의 연구 및 개발이 활발히 이루어지고 있다. 본 논문에서는 강화학습 기법중 Multi-Armed Bandit(MAB) 알고리즘을 활용하여 빌딩 각 방의 조명시스템 전력사용량을 효율적으로 관리함과 동시에 사용자들의 불쾌지수를 최소화할 수 있는 알고리즘을 제안하고, 시뮬레이션을 통해 성능을 검증한다.

• 대기
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• 제23권2호
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• pp.221-229
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• 2013

There has been an increasing need to assess the effects of climate change on human health. It is hard to use climate data to evaluate health effects because such data have a grid format, which could not represent specific cities or provinces. Therefore, the grid-format climate data of South Korea based on RCP (Representative Concentration Pathway) scenarios were modified into area-format climate data according to the major cities or provinces of the country, up to the year 2100. Moreover, heat index (HI) and discomfort index (DI) databases were developed from the modified climate database. These databases will soon be available for experts via a Website, and the expected HI and DI of any place in the country, or at any time, can be found in the country's climate homepage (http://www.climate.go.kr). The HI and DI were analyzed by plotting the average indices every ten years, and by comparing cities or provinces with index level changes, using the geographic information system (GIS). Both the HI and DI are expected to continually increase from 2011 to 2100, and to reach the most dangerous level especially in August 2100. Among the major cities of South Korea, Gwangju showed the highest HI and DI, and Gangwon province is expected to be the least affected area in terms of HI and DI among all the country's provinces.

• 한국환경복원기술학회지
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• 제18권2호
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• pp.79-88
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• 2015

Preparations need to be made for Korean pine(Pinus koraiensis) in anticipation of climate change because Korean pine is an endemic species of South Korea and the source of timber and pine nut. Therefore, climate change adaptation policy has been established to conduct an impact assessment on the distribution of Korean pine. Our objective was to predict the distribution of Korean pine while taking into account uncertainty and afforestation conditions. We used the 5th forest types map, a forest site map and BIOCLIM variables. The climate scenarios are RCP 4.5 and RCP 8.5 for uncertainty and the climate models are 5 regional climate models (HadGEM3RA, RegCM4, SNURCM, GRIMs, WRF). The base period for this study is 1971 to 2000. The target periods are the mid-21st century (2021-2050) and the end of the 21st century (2071-2100). This study used the MaxEnt model, and 50% of the presences were randomly set as training data. The remaining 50% were used as test data, and 10 cross-validated replicates were run. The selected variables were the annual mean temperature (Bio1), the precipitation of the wettest month (Bio13) and the precipitation of the driest month (Bio14). The test data's ROC curve of Korean pine was 0.689. The distribution of Korean pine in the mid-21st century decreased from 11.9% to 37.8% on RCP 4.5 and RCP 8.5. The area of Korean pine at an artificial plantation occupied from 32.1% to 45.4% on both RCPs. The areas at the end of the 21st century declined by 53.9% on RCP 4.5 and by 86.0% on RCP 8.5. The area of Korean pine at an artificial plantation occupied 23.8% on RCP 4.5 and 7.2% on RCP 8.5. Private forests showed more of a decrease than national forests for all subsequent periods. Our results may contribute to the establishment of climate change adaptation policies for considering various adaptation options.

• 한국지리정보학회지
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• 제15권3호
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• pp.119-136
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• 2012

본 연구는 IPCC(Intergovernmental Panel on Climate Change)에서 제시한 기후변화 취약성 개념을 서울시에 적용, 적정 홍수 취약성 지표 산정 및 퍼지모형을 활용하여 기후변화 분야 중 홍수취약성을 평가하고 GIS를 이용하여 취약성도를 작성하였다. 이를 위해 선행연구를 기반으로 지표를 도출하였다. 도출된 지표는 기후노출(일 최대 강수량, 일강수량 80m 이상인 날 수), 민감도(침수지역, 경사, 지질, 고도, 하천으로부터의 거리, 지형, 토양 및 불투수면적) 및 적응능력(홍수조절능력, 자연녹지, 공원녹지) 등의 자료이며, 이를 GIS 기반의 공간데이터베이스로 구축하였다. 구축된 지표값들을 통합하기 위한 방법으로 퍼지모형을 활용했으며, 퍼지소속값 결정을 위해서는 빈도비를 활용하였다. 2010년 침수 발생 자료를 활용하여 항목들간의 상관관계 및 퍼지소속값을 산정하였으며, 2011년 침수 발생 지역으로 작성된 취약성도를 검증하였다. 분석결과 서울지역 홍수피해에 크게 영향을 미치는 지표는 일강수량이 80mm이상인 날수, 하천과의 거리, 불투 수층으로 나타났다. 서울의 경우, 최대강수량이 269mm 이상일 때 적응능력(유수지, 녹지)이 부족하고, 고도가 16~20m 정도이며 하천에서 50m이내에 인접한 지역, 공업용지에서 홍수취약성이 매우 높은 것으로 나타났다. 지역적으로 영등포구, 용산구, 마포구 등 한강 본류의 양안에 위치한 구들이 비교적 취약지역을 많이 포함하고 있는 것으로 나타났다. 본 연구는 기후변화 취약성 평가의 개념을 적용하고, 방법론으로 퍼지모형을 활용함으로써 기존의 취약성 평가기법을 개선하였으며 평가결과는 홍수예방정책에 대한 우선지역 선정과 의사결정의 주요한 근거로 활용될 수 있을 것으로 기대된다.

• 한국기후변화학회지
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• 제8권1호
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• pp.21-30
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• 2017

Recently, There has been much discussed about unused space. This space can be used in a variety of ways. Utilizing it as a facility, craft shop, and utilizing renewable energy generation facilities. Especially, in terms of climate change should be supplied renewable energy. Renewable energy needs to be developed in terms of responding to climate change, and the recent Paris agreement is also emphasizing the importance of renewable energy. In particular, renewable energy needs to be widely disseminated. And renewable energy is limited space. In this regard, idle land can provide opportunities for securing new renewable energy generation facilities. The introduction of new and renewable energy facilities in idle space can enhance the self-sufficiency rate of the local community, which is significant in terms of responding to climate. In this study, to investigate the possibility of utilizing a unused space for a photovoltaic power generation facility, we investigated the amount of electricity which could be generated through photovoltaic power generation, and the economic effects, using a RETScreen model. The results showed that 9,738 MWh of power can be generated and that $4,540tCO_2eqcan$ be saved. Regarding the economic effect, the net present value of the facility was shown to be 2,247,389,020 KRW. As the net present value was shown to be positive, we believe that the installation of a photovoltaic power generation facility in an unused space would have a positive economic effect. We found the net present value following the fluctuation of the SMP price to be positive, though there was some variation. However, as the economic efficiency was shown to be low because the net present value in relation to the maintenance costs was negative, we believe that maintenance costs must be taken fully into account when evaluating economic efficiency. In particular, as subsidies can be used to cover maintenance costs which must be factored into photovoltaic power generation, we believe that photovoltaic power generation can have an economic effect. Because spaces not currently in use can have a positive economic effect as renewable energy power generation facilities, and can also contribute to the reduction of greenhouse gas emissions, unused spaces are thought to greatly help local governments to cope with climate change as well as reinforcing their related capabilities. We believe our study will help local governments with decisions relating to unused real estate utilization in the future.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.185-185
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• 2019

Sustaining future wheat production is challenged by anthropogenically forced climate warming and drying led by increased concentration of greenhouse gases all around the globe. Warming stresses, originating from the elevated $CO_2$ concentration, are continuously reported to have negative impacts on wheat growth and yield. Yet, elevated $CO_2$ concentration, despite being disparagingly blamed for promoting warming, is also associated with a phenomenon called $CO_2$ enrichment; in which wheat yield can improve due to the enhanced photosynthesis rates and less water loss through transpiration. The conflicting nature of climate warming and $CO_2$ enrichment and their interplay can have specific implications under different environments. It is established form the field and simulation studies that the two contrasting phenomena would act severely in their own respect under arid and semi-arid environments. Wheat is a dietary staple for masses in Pakistan. The country's wheat production system is under constant stress to produce more from irrigated agricultural lands, primarily lying under arid to semi-arid environments, to meet the rapidly growing domestic needs. This work comprehensively examines the warming impacts over wheat yield and water productivity (WP), with and without the inclusion of $CO_2$ enrichment, under semi-arid environment of Punjab which is the largest agricultural province of Pakistan. Future wheat yields and WPs were simulated by FAO developed AquaCrop model v 5.0. The model was run using the bias-correction climate change projections up to 2080 under two representative concentration pathways (RCP) scenarios: 4.5 and 8.5. Wheat yield and WPs decreased without considering the $CO_2$ enrichment effects owing to the elevated irrigation demands and accelerated evapotranspiration rates. The results suggested that $CO_2$ enrichment could help maintain the current yield and WPs levels during the 2030s (2021-2050); however, it might not withhold the negative climate warming impacts during the 2060s (2051-2080). Furthermore, 10 - 20 day backward shift in sowing dates could also help ease the constraints imposed by climate warming over wheat yields and WPs. Although, $CO_2$ enrichment showed promises to counteract the adverse climate warming impacts but the interactions between climate warming and $CO_2$ concentrations were quite uncertain and required further examination.