• 한국환경복원기술학회지
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• 제25권3호
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• pp.17-28
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• 2022

We evaluated the effect of CO₂ offsetting by estimating changes in carbon uptake under various forest management scenarios and proposed forest management strategies to achieve carbon neutrality. Paju and Goseong, which have relatively large forest areas but different industrial characteristics, were selected for the study sites. The current state of forest distribution was analyzed using forest type maps and aerial photographs, and the amount of carbon uptake was calculated using the equation presented by the IPCC Guidelines for National Greenhouse Gas Inventories and the national emission/absorption coefficients from the Korea National Greenhouse Gas Inventory Report. As of 2015, the forest carbon absorption in Paju and Goseong was 49,931 t/yr and 94,225 t/yr, respectively, and the annual carbon absorption per unit area was 2.28 t/ha/yr and 2.16 t/ha/yr. Under the forest management scenarios, the annual maximum carbon absorption per unit area is estimated to increase to 5.68 t/ha/yr in Paju and 4.22 t/ha/yr in Goseong, and this absorption would increase further if urban forests were additionally created. Even if the current forests of Paju and Goseong are maintained as they are, emissions from electricity use can be sufficiently offset. However, by applying appropriate forest management strategies, emissions from sectors other than electricity use could be offset. This study can be applied to the establishment of carbon absorption strategies in the forest sector to achieve carbon neutrality.

• Composites Research
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• 제34권6호
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• pp.412-420
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• 2021

본 연구에서는 탄소 단섬유를 천연고무 기지에 혼합한 탄소섬유/고무 시편과 그에 니켈입자를 추가한 탄소섬유-니켈입자/고무 시편의 초기 전기전도도를 측정하고, 그 시편에 압축스트레인을 가하면서 변화하는 전기전도도를 측정하였다. 실험을 통해 탄소섬유의 체적분율 및 추가된 니켈입자, 외부스트레인 등이 전기전도도에 미치는 영향을 관찰하였다. 탄소섬유 체적분율은 작은 차이로도 시편의 전기전도도의 변화에 매우 큰 역할을 하였고, 외부스트레인에 따른 탄소섬유 재배열에 의해 압저항이 증가하는 것을 알 수 있었다. 또한, 니켈입자의 추가는 탄소섬유가 임계체적분율 이상인 시편에서 전기전도도를 개선하는데 기여하는 것을 볼 수 있었는데, 이로부터 외부변형에 따른 탄소섬유의 재배열에 의해 압저항이 증가하는 현상을 상쇄하는 효과가 있음을 확인하였다.

• Wind and Structures
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• 제34권2호
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• pp.199-213
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• 2022

The current study investigates the dynamic effects in the tornado-structure response of an aeroelastic self-supported lattice transmission tower model tested under laboratory simulated tornado-like vortices. The aeroelastic model is designed for a geometric scale of 1:65 and tested under scaled down tornadoes in the Wind Engineering, Energy and Environment (WindEEE) Research Institute. The simulated tornadoes have a similar length scale of 1:65 compared to the full-scale. An extensive experimental parametric study is conducted by offsetting the stationary tornado center with respect to the aeroelastic model. Such aeroelastic testing of a transmission tower under laboratory tornadoes is not reported in the literature. A multiaxial load cell is mounted underneath the base plate to measure the base shear forces and overturning moments applied to the model in three perpendicular directions. A three-axis accelerometer is mounted at the level of the second cross-arm to measure response accelerations to evaluate the natural frequencies through a free-vibration test. Radial, tangential, and axial velocity components of the tornado wind field are measured using cobra probes. Sensitivity analyses are conducted to assess the variation of the structural dynamic response associated with the location of the tornado relative to the lattice transmission tower. Three different layouts representing the change in the orientation of the tower model relative to the components of the tornado-induced loads are considered. The structural responses of the aeroelastic model in terms of base shear forces, overturning moments, and lateral accelerations are measured. The results are utilized to understand the dynamic response of self-supported transmission towers to the tornado-induced loads.

• 아태비즈니스연구
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• 제12권2호
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• pp.187-203
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• 2021

Purpose - The purpose of this study is to analyze the effects of non-tariff barriers on the Free Trade Agreement. Currently, it has achieved significant export effects by signing free trade agreements with many countries in Korea. However, most countries have implemented non-tariff barriers to protect their industries. This study analyzes the effects of non-tariff barriers in counterpart countries that have signed a free trade agreement. Design/methodology/approach - For analysis, first, prior studies were summarized, and second, the current status of free trade agreements and non-tariff barriers were identified. And, based on the current situation, the relationship between non-tariff barriers and export volume was analyzed. The targets of analysis are the United States, China, and Vietnam, which are Korea's three largest exporters. As for non-tariff barriers, anti-dumping tariffs, countervailing tariffs, and emergency import restrictions were analyzed as import regulatory measures. Findings - In the case of the United States, it can be seen that the decline in textiles, steel and electronics sectors is even greater. In the case of China, it can be seen that exports declined after imposing non-tariff barriers in the steel sector. Finally, it can be seen that exports declined after Vietnam implemented a non-tariff barrier on the steel sector. It was found that non-tariff barriers offset the effects of the Free Trade Agreement. Research implications or Originality - Currently, Korea has free trade agreements with numerous countries. However, after the free trade agreement entered into force, the number of annual average import regulation investigations for Korean products is on the rise. In the end, the implementation of non-tariff barriers is offsetting the effects of free trade agreements. Therefore, when signing a free trade agreement, it is necessary to thoroughly prepare for import regulatory measures such as the insertion of provisions of non-tariff barriers.

• 산업융합연구
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• 제20권11호
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• pp.95-104
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• 2022

본 연구는 보육교사 400명을 대상으로 상사무례경험과 플로리싱의 관계에서 복지와 희망이 단순 및 이중 매개하는 지를 분석하여 플로리싱 증진을 위한 기초자료를 제공하는데 목적이 있다. 자료는 오프라인 설문지를 통하여 수집하였으며, SPSS PC+ Win ver. 25.0과 SPSS PROCESS macro ver. 4.1을 활용하여 분석하였고, 빈도분석, 신뢰도분석, 상관분석 및 이중 매개효과 분석을 실시하였다. 연구결과 첫째, 상사무례경험은 복지, 희망 및 플로리싱과 부적인 상관관계를 보였고, 복지, 희망 및 플로리싱은 서로 정적인 상관관계를 보였다. 둘째, 복지와 희망은 상사무례경험과 플로리싱의 관계에서 이중 매개역할을 하였다. 복지와 희망 두 매개변인은 무례경험이 플로리싱에 미치는 음(-)의 영향을 부분적으로 상쇄시키는 역할을 하였다. 결론적으로 복지와 희망의 이중 매개역할을 이용하여 플로리싱을 증진할 수 있음을 확인하였다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.168-168
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• 2022

According to the 5th Climate Change Report, global average temperature in 2081~2100 will increase 1.8℃ based on RCP 4.5 and 3.7℃ based on RCP 8.5 from the current climate value (IPCC Working Group I AR5). As temperature is expected to increase due to global warming and the intensity and frequency of rainfall are expected to increase, damage to crops is expected, and countermeasures must be taken. This study intends to evaluate rice growth in terms of nitrogen utilization efficiency according to future climate change conditions. In this experiment, Oryza sativa cv. Shindongjin were planted at the SPAR facility of the NICS in Wanju-gun, Jeollabuk-do on June 10, and were planted and grown according to the standard cultivation method. Cultivation conditions are high temperature, high CO₂ (current temperature+4.7℃·CO₂ 800ppm), high temperature (current temperature+4.7℃·CO₂ 400ppm), current climate (current tempreture·CO₂ 400 ppm). Nitrogen was varied as 0, 9, 18 kg/10a. The N content and C/N ratio of all rice leaves, stems, and seeds increased at high temperature, and the N content and C/N ratio decreased under high temperature and high CO₂ conditions com pared to high temperature. Compared to the current climate, NUE increases by about 8% under high temperature and high CO₂ conditions and by about 2% under high temperature conditions. This seems to be because the increase in temperature and CO₂ induced the increase in biomass. ANUE related to yield decreased by about 70% compared to the current climate under high temperature conditions, and decreased by about 45% at high temperature and high CO₂, showing a tendency to decrease compared to high temperature. This appears to be due to reduced fertility and poor ripening due to high temperature stress. However, as the nitrogen increased, the number of ears and the number of grains increased, slightly offsetting the production reduction factor.

• 전기학회논문지
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• 제67권5호
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• pp.635-643
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• 2018

This paper propose a method to identify the motor parameters and improve input voltage error which affect the low speed position error of the back-emf(back electromotive force) based sensorless algorithm and to secure the operation reliability and stability even in the case where the load fluctuation is severe and the start and low speed operation frequently occurs. In the model-based observer used in this paper, stator resistance, inductance, and input voltage are particularly influential factors on low speed performance. Stator resistance can cause resistance value fluctuation which may occur in mass production process, and fluctuation of resistance value due to heat generated during operation. The inductance is influenced by the fluctuation due to the manufacturing dispersion and at a low speed where the change of the current is severe. In order to find stator resistance and inductance which have different initial values and fluctuate during operation and have a large influence on sensorless performance at low speed, they are commonly measured through 2-point calculation method by 2-step align current injection. The effect of voltage error is minimized by offsetting the voltage error. In addition, when the command voltage is used, it is difficult to estimate the back-emf due to the relatively large distortion voltage due to the dead time and the voltage drop of the power device. In this paper, we propose a simple circuit and method to detect the voltage by measuring the PWM(Pulse Width Modulation) pulse width and compensate the voltage drop of the power device with the table, thereby minimizing the position error due to the exact estimation of the back-emf at low speed. The suitability of the proposed algorithm is verified through experiment.

• 대한환경공학회지
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• 제36권7호
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• pp.461-468
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• 2014

바이오차(biochar)는 산소가 제한된 환경에서 바이오매스를 열분해를 시켜 얻을 수 있는 고체물질을 말한다. 원료가 되는 바이오매스는 에너지작물, 임업부산물, 농업부산물 등의 폐기물을 사용할 수 있으며, 토양으로 적용 시 기후변화 완화, 화석연료 소비저감, 폐기물 처리비용저감 등의 장점이 있다. 본 연구에서는 폐목재를 원료로 바이오차를 생산하는 시스템을 대상으로 전과정평가 기법에 의해 환경에 미치는 영향을 평가하고자 하였다. 폐목재 1톤을 기능단위로 하였을 때 생산되는 바이오차를 토양에 적용하는 시나리오를 구성하고 지구온난화에 미치는 영향을 중심으로 환경영향을 분석한 결과, 파쇄 및 건조의 전처리 공정에서 4.048E-01 kg, 가스화 열분해공정에서 4.579E-01 kg, 토양살포 공정에서 9.070E-02 kg의 온실가스를 발생하여 총 9.534E-01 kg의 온실가스가 발생하는 것을 확인하였다. 바이오차의 토양적용 시 탄소저장효과는 252 kg으로 분석되어 251 kg의 탄소 네거티브 효과를 보였다.

• 농약과학회지
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• 제3권2호
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• pp.29-36
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• 1999

물리화학적 성질이 상이한 두 종류의 토양으로 충전된 유리 column (5 cm I.D. ${\times}$ 30 cm H.)을 이용하여 bipyridylium계 제초제 paraquat의 용탈을 조사하였다. 토양 A (양토)의 벼 재배구와 무재배구에서 117 일 동안 토양 column으로부터 용탈된 $^{14}C$은 각각 총 처리량의 0.42%와 0.54%이었고, 토양 B (사양토)의 경우에는 각각 0.21%와 0.31%이었다. 벼에 흡수된 $^{14}C$은 토양 A와 B에서 각각 3.87%와 2.79%이었고 대부분이 뿌리에 분포하였다. 두 토양 모두에서 총 처리량의 96% 이상이 토양중에 남아 있었고, 특히 $0{\sim}5$ cm 부위에 대부분 존재하였다. Paraquat 토양잔류물의 물에 의한 추출율은 $6.10{\sim}9.10%$이었고 추출불가 토양잔류물의 분포비율은 humin>humic acid>fulvic acid 순이었다. 벼 무재배구의 토양 pH는 담수의 혐기적 조건때문에 용탈실험 후 증가하였으나 벼 재배구에서의 토양 pH는 벼 뿌리로부터 분비되는 삼출물에 의한 상쇄효과로 증가되지 않았다. 토양중 paraquat의 낮은 이동성은 논에 잔류되어 있는 paraquat에 의한 지하수의 오염가능성이 매우 희박함을 시사해 준다.

• 유통과학연구
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• 제12권6호
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• pp.81-88
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• 2014

Purpose - Entrepreneurship promotion is emerging as an important economic growth agenda. However, in Korea, entrepreneurship has weakened because of the collapse of the venture bubbles of the 2000s and the global economic recession in 2008, which have induced the business community to choose stability over risk. The Korean government has been implementing several support projects to inspire and promote youth entrepreneurship through various means including financial assistance; however, the perpetuation rate of young entrepreneurship is still low as compared to advanced economies such as the US and EU. This case study focuses on the Youth Start-Up Business Support Program of the Small & Medium Business Corporation, and explores practical alternatives. Further, it aims to suggest managerial factors and a conceptual model for change management factors affecting the business performance creation of a startup company, based on the Small and medium Business Corporation's young venture startup fund. Research design, data, and methodology - Many studies examine the current progress and issues of startup firms, for example, a lack of systematic cultivation of entrepreneurship and startup business training, lack of commercialization funding for youth startup businesses, lack of mentoring, and inadequate infrastructure. From prior research, we address four factors, namely, personal managerial capabilities, innovative business model, sufficient cash flow, and social network, affecting startup companies' business performance. This study involved a sample survey of 200 young entrepreneurs to investigate casual relations between the four factors and business performance. A regression analysis was used to verify the hypotheses. Results - First, in relation to differences in the founder's personal characteristics, age, sales amount, and number of employees significantly impact business performance. Second, regarding the causal relation between the four factors for creating business performance, an innovative business model and social networking have supported the hypotheses, revealing that the more that a start-up founder has an innovative business model and social networking, the more the start-up firms are likely to have better performance (e.g., sales volume, employment, ROE, ROI, etc.). Although the founder's competency and sufficient cash flow have no significant relationship with business performance, the mean value was higher performance for high founder's competency and sufficient cash flow. Conclusions - This study provides basic data on policy support strategies of the Small and Medium Business Corporation, to help young entrepreneurs achieve their start-up business goals. It shows that young entrepreneurship startup firms should strive to explore ideas to satisfy customers' needs, and that changes in customer value and the continuous innovation of business model differentiation are required to actively respond to change management. Moreover, at the infant startup stage, they should activate social network programs to share information, thereby offsetting resource scarcity and managing business risk. Further, the establishment of a long-term vision and the implementation of training programs in related specific fields should be supported to strengthen founders' personal capabilities.