• 한국항공운항학회지
• /
• 제28권1호
• /
• pp.7-13
• /
• 2020

A significant growth in local air traffic volume is leading to airway congestion and flight delays especially for Incheon-China and Incheon-Europe sectors. A key method to increase the airway capacity is to place a supplemental airway parallel to the existing one and in cooperation between the aviation authorities between China and Korea, a dual airway track was implemented on December 6, 2018. Here, we use airline A's flight data to analyze the congestion change effect of the new airway. Results show total delay time to Europe is reduced 51% (13.4 to 6.6 minutes) as the delay distribution for 16-30 minutes, 31 minutes and greater decreased from 23.2% to 8.2% and 8.7% to 1.0% respectively. The delay to China also decreased but the drop is not as significant as flights to Europe. This is caused by the difference in flight distance, traffic volume, and characteristics of flights landing and transiting China. Flights to Europe show a broad distribution in altitude allocation and reduction in aircraft separation demonstrating the effectiveness of a dual airway track.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2009년도 하계학술발표대회 논문집
• /
• pp.1435-1439
• /
• 2009

Drainage noise with making think about what they do disturbs neighborhoods live under source of noise. elbow pipe built in the house. the general elbow pipe has a rectangular elbow because of easiness when the plan set up or executing. therefore, free falling fluid impacts on the wall of the elbow pipe almost at one point. in this paper, to disperse the potential energy, the shock decentralizes from tiny area to large area. And It is considered how the characteristics change according to the noise of transformed shape of pipe, then researched the effectiveness of transformed pipe configuration.

• 동력기계공학회지
• /
• 제11권4호
• /
• pp.98-102
• /
• 2007

In this study, a measurement method of leakage flow-rate for pneumatic driving apparatus is proposed. The existing measurement methods of leakage flow-rate of air need disassemble the test component. Therefore, there is no effective method to measure the leakage flow-rate while operating pneumatic driving apparatus. In this study, the leakage flow-rate is measured from the pressure change in an isothermal chamber that can realize isothermal conditions by stuffing the steel wool into it. Therefore, a wide range of flow-rate could be measured only from the pressure response and the leakage flow-rate can be measured during operating pneumatic driving apparatus. The effectiveness of the proposed method is proved by experimental results.

• 유공압시스템학회논문집
• /
• 제3권1호
• /
• pp.15-19
• /
• 2006

In this study, a measurement method of leakage flow-rate for pneumatic driving apparatus is proposed. The existing measurement methods of leakage flow-rate of air need disassemble the test component. Therefore, there is no effective method to measure the leakage flow-rate while operating pneumatic driving apparatus. In this study, the leakage flow-rate is measure from the pressure change in an isothermal chamber that can realize isothermal conditions by stuffing steel wool into it. Therefore, wide range of flow-rate could be measured only from the pressure response and the leakage flow-rate can be measured during operating pneumatic driving apparatus. The effectiveness of the proposed method is proved by experimental results.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2018년도 전력전자학술대회
• /
• pp.382-383
• /
• 2018

To increase the efficiency of a wind energy conversion system (WECS), the maximum power point tracking (MPPT) algorithm is usually employed. This paper proposes an optimal MPPT algorithm which tracks a sudden wind speed change condition fast. The proposed method can be implemented without the prior information on the wind turbine parameters, generator parameters, air density or wind speed. By investigating the directions of changes of the mechanical output power in wind turbine and rotor speed of the generator, the proposed MPPT algorithm is able to determine an optimal speed to achieve the maximum power point. Then, this optimal speed is set to the reference of the speed control loop. As a result, the proposed MPPT algorithm forces the system to operate at the maximum power point by using a three-phase converter. The simulation results based on the PSIM are given to prove the effectiveness of the proposed method.

• Journal of Information Processing Systems
• /
• 제10권2호
• /
• pp.163-175
• /
• 2014

This paper will focus on improving the performance of orthogonal frequency division multiplexing (OFDM) in Rayleigh fading environments. The proposed technique will use a previously published method that has been shown to improve OFDM performance in independent fading, based on ordered sub-carrier selection. Then, a simple non-iterative method for finding the optimal bit-loading allocation was proposed. It was also based on ordered sub-carrier selection. We compared both of these algorithms to an optimal bit-loading solution to determine their effectiveness in a correlated fading environment. The correlated fading was simulated using the JTC channel models. Our intent was not to create an optimal solution, but to create a low complexity solution that can be used in a wireless environment in which the channel conditions change rapidly and that require a simple algorithm for fast bit loading.

• 한국환경복원기술학회지
• /
• 제23권5호
• /
• pp.87-98
• /
• 2020

At the point of implementing policies related to urban heat through the overall environmental assessment of the city using national data, citizen science projects that can collect data in a wide range are emerging for effective policy establishment. Although the utility of citizen data is improving, data quality is a primary concern for researchers employing public participation in scientific research. In this study, validation was conducted based on citizen data acquired in the "Suwon City Heat Map Project", and the applicability to temperature monitoring was confirmed based on the results. As a result of analyzing the validity verification of citizen data using three methods, the data result value is 0.843, RMSE: 0.683℃, and a meaningful value was found within 3km of national data. We found that citizen data utilization is high through the results of this study and These projects are expected to be used as basic data for establishing effective policies or can be reflected in the various planning.

• Journal of Acupuncture Research
• /
• 제39권3호
• /
• pp.202-212
• /
• 2022

Background: The aim of this study was to evaluate the effectiveness and safety of Cheong-A-Won Gagambang (JCE003) treatment for degenerative knee osteoarthritis. Methods: This was a single-center, randomized, double-blind, placebo-controlled pilot clinical trial. There were 36 adults with degenerative knee osteoarthritis who were randomly allocated into JCE003 1,000 mg, JCE003 2,000 mg, or the placebo group (in a 1:1:1 ratio). The participants received 12 weeks of treatment and had scheduled tests every 6 weeks. The primary outcomes were measured using the Korean Western Ontario and McMaster Universities scale, and the secondary outcomes were measured using the visual analog scale, European quality of life-5-dimensions, patient global impression of change, C-reactive protein, and erythrocyte sedimentation rate. Changes between baseline scores and scores following study completion were analyzed. Results: There were 29 participants whose data were analyzed in this study. The change of Korean Western Ontario and McMaster Universities, visual analog scale, European quality of life-5-dimensions scores showed significant improvement in the JCE003 1,000 mg group. The change of patient global impression of change was significantly improved in the placebo group. There were 14 adverse events, but there was no clinically significant relationship with the intake of JCE003 compared with the placebo. Conclusion: Taking JCE003 may be effective at improving knee pain in patients with degenerative knee osteoarthritis and appears to be safe. Based on this study, the concentration and feasibility of the test group may be used when conducting a large-scale clinical trial of degenerative knee osteoarthritis in the future.

• 한국조경학회지
• /
• 제51권5호
• /
• pp.70-83
• /
• 2023

최근 산림청이 기후 변화 대응 대책으로써 지자체 바람길숲 조성 사업을 시행함에 따라 다양한 바람길에 대한 연구가 수행되어 오고 있다. 바람길숲 조성을 위해서는 바람길 기능에 대한 평가가 선행되어야 한다. 하지만, 현재 바람길을 직접적으로 평가하고, 바람길의 유형에 따라 공간을 구분할 평가 지표가 없어 간접적인 지표를 기준으로 분석을 수행하고 있다. 따라서 본 연구에서는 냉각에너지 분석을 찬공기 생성에 대한 평가 지표로 활용함으로써 바람길을 평가 및 분류하는 방법을 제안하였다. Kaltluftabflussmodell_21(KLAM_21)이라는 찬공기 분석 모형을 활용하여 냉각에너지 분석을 하였다. 그리고 시뮬레이션 분석 결과에 따라 바람길을 찬공기 생성지역, 찬공기 취약지역, 찬공기 유동지역으로 분류하였다. 냉각에너지량을 기준으로 상위 5퍼센트를 찬공기 생성지역, 하위 5퍼센트를 찬공기 취약지역으로 분류하였다. 또한 찬공기 유동지역은 찬공기 생성지역에서 이동하는 찬공기의 흐름을 파악하여 분류하였다. 분석 결과, 대구광역시의 바람길 6개의 바람 생성지역이 존재하며, 찬공기 취약지역은 시가지 내부에 집중되어 있었고, 찬공기 유동지역은 대구광역시의 주요 하천과 도로를 따라 형성되어 있었다. 본 연구의 방법론을 통해 바람길의 효과를 정량적 평가 방법으로 활용될 수 있을 것으로 기대된다. 또한 바람길숲 조성 사업지 선정에 제시할 수 있는 평가 지표로 활용될 것으로 판단된다.

• 한국환경보건학회지
• /
• 제49권6호
• /
• pp.362-371
• /
• 2023

Background: PM_2.5 pollution has been a persistent problem in South Korea, with concentrations consistently exceeding World Health Organization (WHO) guidelines. The aging of the population in the country further exacerbates the health impacts of PM_2.5 since older adults are more susceptible to the adverse effects of air pollution. Objectives: This study aims to evaluate how the health impact (premature death) due to long-term exposure to PM_2.5 in South Korea could change in the future according to the trend of change in the country's population structure. Methods: The study employs a relative risk function, which accounts for age-specific relative risks, to assess the changes in premature deaths by age and region at the average annual PM_2.5 concentration for 2022 and at PM_2.5 concentration improvement levels. Premature deaths were estimated using the Global Exposure Mortality Model (GEMM). Results: The findings indicate that the increase in premature deaths resulting from the projected population structure changes up to 2050 would significantly outweigh the health benefits (reduction in premature deaths) compared to 2012. This is primarily attributed to the rising number of premature deaths among the elderly due to population aging. Furthermore, the study suggests that the effectiveness of the current domestic PM_2.5 standard would be halved by 2050 due to the increasing impact of population aging on PM_2.5-related mortality. Conclusions: The study highlights the importance of considering trends in population structure when evaluating the health benefits of air pollution reduction measures. By comparing and evaluating the health benefits in reflection of changes in population structure to the predicted PM_2.5 concentration improvements at the provincial level, a more comprehensive assessment of regional air quality management strategies can be achieved.