• THE INDUSTRY AND TECHNOLOGY OF GAS
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• v.2 no.1
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• pp.6-21
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• 1998

에너지는 인류문명발달의 원동력이며 현대 산업사회에서는 모든 산업활동과 국민경제에 필수적인 요소이므로 세계 거의 모든 나라들은 에너지의 안정확보를 국가정책의 제 1로 삼고 있다. 세계적으로 볼 때 시대의 변천에 따라 에너지의 주역도 바뀌어 산업혁명 후 제2차 세계 대전까지는 석탄이 주역이었고, 2차대전 후 1970년대 석유위기 전까지는 석유가 단연 주역이었다가 석유위기 후 1980년대는 천연가스와 원자력이 상당부문 석유를 대체하고 있으며, 21세기에는 가스이용기술의 개발에 따라 편리성과 경제성에서 가스의 우월성으로 타에너지를 대체하고, 특히 지구온난화방지 노력과 관련하여 전세계적인 $CO_2$ 감축 목표에 따라 청정연료로서 타에너지 보다 사용이 크게 늘어 2010년까지는 1995년의 $50\%$가 증가하여 21세기 연료의 주역이 될 것으로 전망된다. 우리나라는 에너지의 $98\%$를 외국에서 도입하는 상황에서 석유의존도가 $60\%$를 넘고 있으며, 원자력발전소의 확장에 어려움이 많고 세계기후변화협약을 비준한 국가로서 지구온난화방지를 위한 의무를 지게 될 것이므로, 에너지 공급원의 다원화를 통한 안정확보와 청정에너지 이용의 확대 및 에너지 산업에 대한 규제완화 등으로 경제성에 입각한 시장경쟁에서 가스는 우위를 확보함으로써 1차 에너지중 가스의 비중이 매우 높아질 것으로 전망되고있다. 따라서 가스산업은 우리나라 에너지산업중 가장 크게 발전하고 또 다른 에너지가 여러면에서 제약을 받게 될 때 이러한 제약을 극복하는 대체에너지로서 역할이 크게 전망되며, 특히 발전, 열병합, 냉방, 자동차 연료부문에서의 사용이 크게 늘어날 것으로 예상되어 이러한 가스이용의 확대에 대비하여 가스자원의 개발, 국내 공급설비의 확충, 연구개발등에 대한 투자와 규제완화에 의한 시장경쟁에 대한 대비가 필요하다.계산모델 및 원자력병원에서 보유하고 있는 방사선 치료계획장치인 CAP-PLAN의 선량계산모델의 계산 결과와 비교하여, 흡수선량은 ${\pm}10\%$ 이내에서 거리로는 0.4mm 이내에서 대부분 일치하였다. 최대 오차는 각각 $11.3\%$ 및 0.8mm로 나타났다. 이상의 결과들로부터 새로 개발한 금으로 된 기구와 Ir-192 seed를 이용한 근접 방사선 치료법으로 안구의 악성종양에 대한 치료를 보다 효과적으로 시행할 수 있을 것으로 기대된다. 구성원을 간소 목적을 위하여 사용할 수 있어야 하겠다 마지막으로 이들 내의 위험 집단을 우선적으로 파악. 접근하여야 할 것이다. 위험 집단으로는 경제적 문제로 적절한 의료 이용을 할 수 없는 저소득층, 문화적으로 열등한 위치에 있는 여성층과 초기 이민 적응에 가장 문제를 일으킬 소지가 있는 노년층을 들 수 있겠다. 이 연구는 몇 가지 제한점을 가진다. 첫째. 연구 대상자 선정이 어려워서 자원자를 대상으로 연구가 행해졌다. 둘째. 적은 수의 연구 대상자를 대상으로 연구가 행해졌다. 셋째. 연구기간이 짧았던 까닭에 좀더 상세한 사례 연구가 이루어질 수 없었다 좀 더 신뢰할 수 있는 표본 추출 방법을 통하여 선정된, 많은 연구 대상자를 가지고, 심도 있는 연구가 추후 반복적으로 이루어져야 할 것이다.더욱 더 발전을 거듭하고 있으며, 외식은 여행과 여가 활동의 필수적인 요소로써 그 역할을 일조하고 있다. 이와 같은 여가시간의 증가는 독신자들에게는 좀더 많은 여유시간을 가족을 이루고 있는 가족구성원들에게는 가족과의 유대를 강화하는 휴식과 오락의 소비 트렌드를 창출시켰다. 이와 더불어 외식은 식사를 해결하기 위한 단순한 수단에서 벗어나 동기와 동반자에 따라 달라지는 행동 패턴을 나타내고 있으며, 연령과 목적에 따라 세분화되는 분명한 선호도를 나타낸다. 지난 10여 년간 외국으로부터 수입된 다양한

• Clean Technology
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• v.24 no.3
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• pp.212-220
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• 2018

Oxy-fuel combustion is considered as a promising greenhouse gas reduction technology in power plant. In this study, the behaviors of NO and $SO_2$ were investigated under the condition that in-furnace $deNO_x$ and $deSO_x$ methods are applied in oxy-fuel circulating fluidized bed combustion condition. In addition, the generation trends of $SO_3$, $NH_3$ and $N_2O$ were observed. For the purpose, limestone and urea solution were directly injected into the circulating fluidized bed combustor. The in-furnace $deSO_x$ method using limestone could reduce the $SO_2$ concentration in exhaust gas from ~403 to ~41 ppm. At the same experimental condition, the $SO_3$ concentration in exhaust gas was also reduced from ~3.9 to ~1.4 ppm. This trend is mainly due to the reduction of $SO_2$. The $SO_2$ is the main source of the formation of $SO_3$. The negative effect of $CaCO_3$ in limestone, however, was also appeared that it promotes the NO generation. The NO concentration in exhaust gas reduced to ~26 - 34 ppm by appling selective non-catalytic reduction method using urea solution. The $NH_3$ concentration in exhaust gas was appeared up to ~1.8 ppm during injection of urea solution. At the same time, the $N_2O$ generation also increased with increase of urea solution injection. It seems that the HNCO generated from pyrolysis of urea converted into $N_2O$ in combustion atmosphere. From the results in this study, the generation of other pollutants should be checked as the in-furnace $deNO_x$ and $deSO_x$ methods are applied.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.189-197
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• 2013

The Cancun Agreements under the United Nations Framework Convention on Climate Change require developing countries aiming to undertake REDD+ activities to develop a national strategy or action plan, addressing the drivers of deforestation and forest degradation, a measurement, reporting and verifying (MRV) system including forest monitoring system, and safeguards to ensure equity and co-benefits for local communities and indigenous peoples, and biodiversity. The Government of Indonesia and the Government of Norway established REDD+ cooperation through signing a 'Letter of Intent' in May, 2010. Indonesia agreed on 'a two year suspension on all new concessions for conversion of peat and natural forest'. In turn, Norway agreed to support Indonesia's REDD+ implementation efforts up to one billion United States dollars. Indonesia's REDD+ national strategy (June, 2012) accepted most of the requests included in the 'Letter of Intent'. The REDD+ national strategy, however, does not reflect requests of the Cancun Agreements which noted identification of the drivers of deforestation and forest degradation and guarantee of real greenhouse gas emissions reductions. Indonesia lays emphasis on Norwegian requests which includes expected financial support rather than the Cancun Agreements which have a weak legally-binding requirements.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.1
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• pp.1-13
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• 2019

With commercial apps popular in EU, MaaS has been emerging around the globe as a new approach to worsening urban traffic problems. In contrast, it is still mainstay in Korea simply discussing the concept and necessities of MaaS, rather than seeking for real-world solutions for the commercialization. The purpose of this research is to analyze the demand-side i1mpacts of travel time and cost changes according to MaaS adoption, and to see its commercial feasibility in Korea. The 2010 KTDB traveler's nationwide OD data is used to estimate the level of fare discount for balancing the mode shift and fare revenue changes followed by MaaS implementation. The analysis results show that MaaS leads to the increase of public transport ridership as a result of the diminishing travel cost and time, and that the time saving works more positively for ridership increase. Also, the optimum level of fare discount is estimated 2.56% without damaging the revenue. This finding reveals that MaaS impact is superior to the other single-sided public transport inventive measures since it can affect both travel cost and time reduction at the same time.

• Journal of Environmental Impact Assessment
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• v.26 no.2
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• pp.127-139
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• 2017

Measurements of net ecosystem exchange (NEE) of $CO_2$ based on the eddy covariance technique provide reasonable carbon balance estimates in response to local environmental conditions. In South Korea, the forest ecosystems cover approximately 64% of the total area, thereby strongly affecting regional carbon balances. Cultivated croplands that cover about 17% of the total area should also be considered when calculating the carbon balance of the country. In this study, our objectives were (a) to quantify the range and seasonal variation of NEE at forest ecosystems, including deciduous, coniferous, and mixed forests, and agricultural ecosystems, including rice paddies and a potato field, in South Korea and (b) to compare NEE at ten Fluxnet sites that have the same or similar ecosystems as found in South Korea. The results showed that the forest and agricultural ecosystems were carbon sinks. In Korea, NEE at the forest ecosystems varied between -31 and $-362gC/m^2/yr$, and NEE at the croplands ranged from -210 to $-248gC/m^2/growing$ season. At the deciduous forest, NEE reached low values in late spring, early summer, and early autumn, while at the coniferous forest, it reached low values in spring, early summer, and mid autumn. The young mixed forest was a much stronger carbon sink than the old-growth deciduous and coniferous forests. During each crop growing season, beet had the lowest NEE value within six crops, followed by wither wheat, maize, rice, potato, and soybean. These results will be useful for designing and applying management strategies for the reduction of $CO_2$ emissions.

• Korean Journal of Construction Engineering and Management
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• v.12 no.6
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• pp.101-109
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• 2011

As climate change is becoming the main issue, various efforts are focused on saving building energy consumption both at home and abroad. In particular, it is very important to save energy by maintenance, repair and rehabilitation of existing multi-family housing complex, because energy consumption in residential buildings is not only forming a great part of gross energy consumption in Korea but the number of deteriorated complexes is also sharply increasing. However, energy saving is not considered as a main factor in decision making on rehabilitation project. Also, any supporting tool is not appropriately prepared in existing process. As the first step for development of decision support system on rehabilitation, this paper developed a breakdown structure, which makes clusters of multi-family housing complexes. Decision tree, one of data mining methods, was used to make clusters based on the characteristics and energy consumption data of multi-family housing complexes. Energy saving and CO2 reduction will be maximized by considering energy consumption during rehabilitation process of multi-family housing complex, based on these results and following research.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.729-738
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• 2017

With the signing of the Paris Agreement, which is the new climate change agreement at the end of 2015, it will have a great impact on Korea environmental policy. The construction industry, which accounts for 42% of Korea's total $CO_2$ emissions, has been implementing various policies to improve the environmental problems. However, it is only applying passively to other projects except eco-friendly building certification. This is because most of the eco-related systems are based on building facilities. Therefore, there is a need for a new eco - friendly design evaluation model that can be widely applied not only to architecture but also to civil engineering facilities. In this study, a new model is developed based on the existing VE model, which adds new factors to evaluate the environmental friendliness, potential environmental pollution concept and environmental risk of facilities. This model is an eco-friendly design evaluation model that enables decision makers to effectively select alternative environmental criteria at the design stage. As a result of the case analysis of the block retaining wall and the alternative retaining wall, the value of the eco - friendly value of the alternative was 1.026 times higher than the original one. If this model is used at the design stage, it is expected to contribute not only to the construction of environmentally friendly facilities but also to the reduction of carbon emissions.

• Journal of Energy Engineering
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• v.28 no.3
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• pp.42-54
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• 2019

The solar and wind power is spreading as a means to $CO_2$ reduction, but it has the characteristics of the volatility depending on the weather changes. This article aims to estimate the additional integration costs in Korea electric system in response to such volatility of increasing solar and wind power generation, using Korea electric power trading analyzer(KEPTA). The analysis utilizes the statistics of "8th Basic Plan for Long-term Electricity Supply and Demand" and "Renewable Energy Plan 3020". As the results, integration costs will be estimated 13.94Won/kWh~32.55Won/kWh, consisting of 8.94Won/kWh as back-up costs, 1.03Won/kWh~4.45Won/kWh as balancing costs, and 3.97Won/kWh~19.16Won/kWh as grid-costs. These results suggest that when the integration costs are secured, Korea electric system will be expected in the stable situation. This article leaves the further studies with taking the technological development of solar and wind power generation, the introduction of energy storage system, and wholesale price of electricity into consideration.

• Environmental and Resource Economics Review
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• v.29 no.4
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• pp.499-520
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• 2020

Input ratio of electricity to other production inputs in the Korean manufacturing sector has been higher than for the other OECD countries. In addition, electricity prices in Korea has been relatively lower than the average of OECD countries. Moreover, electricity sector is responsible for most CO2 emissions in Korea as coal and natural gas account 41.9% and 26.8% of electricity production as of 2018. Therefore, it looks inevitable to raise the electricity tariff for the manufacturing sector in Korea, but there is a concern that increase in the electricity tariff might affect small and medium enterprises (SMEs) more than large firms. This study estimates electricity demand's price and output elasticities for large firms and SMEs in steel industry by employing a time varying parameter model (Kalman filter). The analysis shows that changes in output levels regardless of firms' size affect electricity demands more significantly than do changes in electricity prices. Second, large firms have higher variances for both price and output elasticities of electricity demand. Third, large firms have higher price elasticity but lower output elasticity of electricity demand relative to SMEs. Policy implications are suggested in association with how to reduce electricity demands in the energy-intensive industry.

• Journal of Chest Surgery
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• v.40 no.3 s.272
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• pp.200-208
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• 2007

Background: The effect of patient-prosthesis mismatch (PPM) on the clinical outcome following aortic valve replacement (AVR) remains controversial. This study compared the surgical outcomes of AVR between patients with a patient-prosthesis mismatch and those having undergone an aortic annular enlargement. Material and Method: Six hundred and twenty seven adult patients, who underwent AVR with stented bioprosthetic or mechanical valves, between January 1996 and February 2006, were evaluated. PPM was defined as an indexed effective orifice area (iEOA) ${\leq}0.85cm^2/m^2$, and Severe if the iEOA${\leq}0.65cm^2/m^2$ PPM was present in 103 (16.4%, PPM group) patients, and severe in 11 (1.8%, SPPM group). During the period of the study, 21 patients underwent an AVR with annular enlargement (AE group). Result: The mean iEOA of the AE group was larger than that of the PPM group ($0.95\;vs.\;0.76cm^2/m^2,\;p=0.00$). The AE group had longer CPB, ACC and operation times than the PPM group, and showed a tendency toward higher operative mortality (14.3% vs. 2.9%, p=0.06). The SPPM group had higher AV pressure gradients (peak/mean) than the AE group (72/45 mmHg vs. 38/25 mmHg, p=0.02/0.06) and suffered more AV related events (AV reoperation or severe aortic stenosis)(45.5% vs. 9.5%, p=0.03). LV masses were not regressed in the patients who experienced an AV related event. Conclusion: During AVR in patients with a small aortic annulus, annular enlargement should be carefully applied taking into account the high risk of operative mortality due to annular enlargement and co-morbidities of patients. Aortic annular enlargement; however, should be considered as an alternative method in patients expected to have a severe PPM after an AVR.