• 한국지리정보학회지
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• 제12권4호
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• pp.182-190
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• 2009

자동차 보유대수 증가에 따른 교통 혼잡과 대기오염 및 에너지 과다사용 문제를 극복하기 위해 녹색교통수단인 자전거이용의 중요성이 현저하게 대두되고 있지만, 부산시는 지형적 특성과 대중교통 접근성의 한계 등으로 인해 자전거 이용률이 상대적으로 낮은 실정이다. 따라서 지리적 여건과 이용활성화를 고려한 자전거도로의 노선선정이 이루어져야 할 것이다. 본 연구는 계층분석법(AHP)을 이용하여 노선선정 인자의 가중치를 산정하고, GIS 소프트웨어를 이용하여 데이터베이스를 구축한 뒤, 산정된 가중치를 적용하여 노선을 도출하였다. GIS 기반에서 AHP 분석을 수행한 결과, 조사의 일관성을 검증함으로써 신뢰성 있는 자료를 얻을 수 있었고 임의로 선정된 노선보다 이용수요가 많은 곳으로 노선이 도출되었다. 따라서 향후 지역의 특수성을 반영한 노선선정이나 투자 우선순위 결정 등에 본 연구가 활용될 것으로 기대된다.

• 한국항공운항학회지
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• 제15권4호
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• pp.100-107
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• 2007

We proposed the concatenation of logistics' Information to constructing the intelligent logistics city that is to manage efficiently cargo distribution as providing at real-time information of cargo location trace and management through the Telematics/RFID. Case of the Incheon of the "Air Logistics Hub", this area is on an increasing trend on the quantity of cargo transport of the Air & Sea cargo system until 2006. As intelligent project of the Air's and the Sea's field is independently developed at each area, it is a problem on the concatenation of logistics' information such as freight location trace and management, operation management and route information of cargo vehicles. Therefore, we propose the advanced transport service model for the concatenating smoothly of Air & Sea cargo system. In this paper, we only manage the model of Air & Sea cargo system of the advance logistics city.

• 한국항공운항학회지
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• 제28권4호
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• pp.164-170
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• 2020

Recently, the aviation industry faced a major crisis due to the impact of COVID-19. However, despite the sluggish passenger transportation, the cargo transportation sector is relatively maintained or increasing depending on the item. In this study, we will look at the trends before and after COVID-19, focusing on the cargo export field, which is a concern of the aviation industry. First, it analyzes the entire air cargo and then analyzes the trends of each item and country in detail. In particular, it examines the process of changes in air transport costs, which increased significantly immediately after COVID-19, and conducts future trends and prospects in the cargo export field. As a result of the study, some characteristics of air cargo exports before and after COVID-19 were found in an analysis by item and country, and transportation costs varied according to route distance.

• 한국ITS학회 논문지
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• 제9권1호
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• pp.91-100
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• 2010

최근 항공교통량의 증가에 따라 보다 효율적인 항공교통흐름제어가 요구되고 있다. 이에 본 논문에서는 효율적인 항공교통흐름제어를 위한 알고리즘을 제안하였다. 항공통신 환경은 일반 통신 환경과는 다르게 스테이션(항공기) 사이에 직접적인 통신 기능이 필요하며, 안전성을 위한 메시지의 우선순위가 매우 엄격하게 요구된다. 게다가 넓은 서비스 지역은 높은 전파지연을 발생시킨다. 본 논문에서는 기존의 CSMA/CA 매체접속제어(MAC) 프로토콜을 사용하여 항공교통상황(혼잡 공항 지역, 접근관제구역, En route구역, 대양 항행)에 따라 메시지 우선순위를 설정하고, 이러한 우선순위가 높은 메시지가 보다 더 높은 접속 확률을 갖고 데이터를 전송하도록 하였다. 항공기 대수에 따른 시뮬레이션 결과, 교통량이 증가할수록 기존 방식보다 더 높은 채널 사용 효율 및 전송확률을 가짐을 확인하였다.

• Environmental Analysis Health and Toxicology
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• 제17권2호
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• pp.125-133
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• 2002

Volatile disinfection by-products (DBPs) contained in chlorinated tap water are released into household air during indoor activities (showering, cooking, dish -washing, etc.) associated with tap water uses and may cause adverse health effects on humans. Twenty seven subjects were recruited and their homes were visited during the winter of 2002. Tap water, household air, and exhaled breath samples were collected and analyzed for five volatile DBPs (chloroform, bromodichloromethane, dichloroacetonitrile, 1,1 -dichloropropanone and 1,1,1 trichloropropanone). Chloroform was a major DBP found in most samples. Tap water chloroform concentrations were not statistically correlated with its household air concentrations, probably due to individual variability in indoor activities such as showering, cooking, and dish - washing as well as household ventilation. Correlation of breath chloroform concentration with household air chloroform concentration showed its possible use as a biomarker of exposure to household air chloroform. Exposure estimates suggested that inhalation during household stay be a major route of exposure to volatile DBPs and that ingestion of tap water be a trivial contributor to the total exposure in Koreans.

• 한국항공운항학회지
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• 제28권1호
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• pp.22-33
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• 2020

Due to recent increased air traffic,, air traffic controllers in charge of en-route and approach control have faced huge increase in both workload and its intensity. The purpose of this paper is to analyze how much safety culture of air traffic controllers has effect on their complexity mitigation strategies during their duties. It could be expected complexity mitigation improve air traffic flow resulting in enhancing safety eventually. According to empirical analysis against air traffic controllers in civil aviation and air force in South Korea, it was proven safety culture had a statistically positive effect on complex mitigation strategies through safety behavior. In safety culture among air traffic controllers, intrinsic culture had a positive effect on extrinsic value of safety culture. Intrinsic value of safety culture led to air traffic controllers' safety behavior which created work complexity mitigation strategies. Among work complexity mitigation strategies, communication and cooperation was proven to be the most important factor effected by safety culture and behavior. It was implied that enhancing the intrinsic values of safety culture would cause to improve extrinsic safety culture and air traffic controller's work efficiency.

• 유통과학연구
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• 제12권2호
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• pp.59-71
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• 2014

Purpose - In recent years, many firms have attempted various approaches to cope with the continual increase of aviation transportation. The previous research into freight charge forecasting models has focused on regression analyses using a few influence factors to calculate the future price. However, these approaches have limitations that make them difficult to apply into practice: They cannot respond promptly to small price changes and their predictive power is relatively low. Therefore, the current study proposes a freight charge-forecasting model using time series data instead a regression approach. The main purposes of this study can thus be summarized as follows. First, a proper model for freight charge using the autoregressive integrated moving average (ARIMA) model, which is mainly used for time series forecast, is presented. Second, a modified ARIMA model for freight charge prediction and the standard process of determining freight charge based on the model is presented. Third, a straightforward freight charge prediction model for practitioners to apply and utilize is presented. Research design, data, and methodology - To develop a new freight charge model, this study proposes the ARIMAC(p,q) model, which applies time difference constantly to address the correlation coefficient (autocorrelation function and partial autocorrelation function) problem as it appears in the ARIMA(p,q) model and materialize an error-adjusted ARIMAC(p,q). Cargo Account Settlement Systems (CASS) data from the International Air Transport Association (IATA) are used to predict the air freight charge. In the modeling, freight charge data for 72 months (from January 2006 to December 2011) are used for the training set, and a prediction interval of 23 months (from January 2012 to November 2013) is used for the validation set. The freight charge from November 2012 to November 2013 is predicted for three routes - Los Angeles, Miami, and Vienna - and the accuracy of the prediction interval is analyzed using mean absolute percentage error (MAPE). Results - The result of the proposed model shows better accuracy of prediction because the MAPE of the error-adjusted ARIMAC model is 10% and the MAPE of ARIMAC is 11.2% for the L.A. route. For the Miami route, the proposed model also shows slightly better accuracy in that the MAPE of the error-adjusted ARIMAC model is 3.5%, while that of ARIMAC is 3.7%. However, for the Vienna route, the accuracy of ARIMAC is better because the MAPE of ARIMAC is 14.5% and the MAPE of the error-adjusted ARIMAC model is 15.7%. Conclusions - The accuracy of the error-adjusted ARIMAC model appears better when a route's freight charge variance is large, and the accuracy of ARIMA is better when the freight charge variance is small or has a trend of ascent or descent. From the results, it can be concluded that the ARIMAC model, which uses moving averages, has less predictive power for small price changes, while the error-adjusted ARIMAC model, which uses error correction, has the advantage of being able to respond to price changes quickly.

• 한국연소학회지
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• 제18권4호
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• pp.37-43
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• 2013

The effects of preferential diffusion of hydrogen in interacting counterflow $H_2$-air and CO-air premixed flames were investigated numerically. The global strain rate was varied in the range $30-5917s^{-1}$, where the upper bound of this range corresponds to the flame-stretch limit. Preferential diffusion of hydrogen was studied by comparing flame structures for a mixed average diffusivity with those where the diffusivities of H, $H_2$ and $N_2$ were assumed to be equal. Flame stability diagrams are presented, which show the mapping of the limits of the concentrations of $H_2$ and CO as a function of the strain rate. The main oxidation route for CO is $CO+O_2{\rightarrow}CO_2+O$, which is characterized by relatively slow chemical kinetics; however, a much faster route, namely $CO+OH{\rightarrow}CO_2+H$, can be significant, provided that hydrogen from the $H_2$-air flame is penetrated and then participates in the CO-oxidation. This modifies the flame characteristics in the downstream interaction between the $H_2$-air and CO-air flames, and can cause the interaction characteristics at the rich and lean extinction boundaries not to depend on the Lewis number of the deficient reactant, but rather to depend on chemical interaction between the two flames. Such anomalous behaviors include a partial opening of the upper lean extinction boundary in the interaction between a lean $H_2$-air flame and a lean CO-air flame, as well as the formation of two islands of flame sustainability in a partially premixed configuration with a rich $H_2$-air flame and a lean CO-air flame. At large strain rates, there are two islands where the flame can survive, depending on the nature of the interaction between the two flames. Furthermore, the preferential diffusion of hydrogen extends both the lean and the rich extinction boundaries.

• 한국항행학회논문지
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• 제24권3호
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• pp.173-183
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• 2020

본 연구는 인천국제공항(ICN)-두바이국제공항(DXB)의 정기 노선을 취항하고 있는 대한민국 국적항공사 및 중동 국적항공사를 이용객들을 연구의 대상으로 하였다. 항공시장의 자유화 압박 속에서 국적항공사 대(對) 외국항공사의 시장 경쟁이 가장 치열한 노선들 중 하나이기 때문이다. 실증연구를 통해 국적항공사의 경쟁적 우위는 무엇이고 향후 시장 자유화 확대 기조에서 치열한 경쟁에서 살아남기 위한 지속가능한 전략이 무엇인지 시사점을 도출하고자 하였다. 인천-두바이 노선에서 국적항공사 이용객들의 우수한 제품 편익에 대한 인식은 가격 프리미엄을 지불하고서라도 재구매 의도에 유의한 영향을 미치는 것으로 판명되었다. 반면 외국항공사 이용객들의 제품 편익은 저렴한 가격과 아무런 상관성이 없는 것으로 분석되었다. 국적 항공사의 제품 편익을 향후 더욱 강화한다면, 동 노선에서 외국 항공사들의 가격 우월성과 경쟁하고 시장에서 경쟁적 우위를 지속적으로 유지할 수 있을 것이다.

• 항공우주정책ㆍ법학회지
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• 제5권
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• pp.303-320
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• 1993

The construction of New Seoul International Airport is under way despite much controversy. Among much discussed, but not well-formulated controversy is the possibility of the airport as a hub in the North Asia Region. This paper specifies the factors which render it possible for an airport to be a regional hub. Then each factor is applied to the new airport to see whether it can function as a hub airport. Also examined is the qualitative cost and benefit calculation related to the hub function. The usual discussion has missed one big point of cost side of hub function in the belief that the hub only produces benefits to the national economy where the airline and airport industry belong; earlier-than-expected congestion and the necessity to expand the airport sufficiently enough to accommodate the increasing air demand. An airport as a hub is determined by several factors; geographical location ; economic status of the country where the airport belongs ; bilateral air service agreements according to which the airlines can exercise the route rights; the airport charges which directly influence the cost structure of the carriers ; international aviation and airport related policies of each country in the region ; airport capacity etc. The tentative implications of this paper are the followings; first, the new airport is able to function as a regional hub in the transpacific routes which connect Asian countries and North America. That is, directional hubbing by the airlines is implicated; second, the main benefits may be accrued to american airlines exercising all the route rights in the Asian region; third, the governmental effort to make the new airport a regional hub must take caution in optimizing the hubbing level (% of transitting passengers and freight) between the benefits and the costs. Further Studies may include optimal level of hubbing for the new airport and, quantification of the impact of the new airport on the national economy depending on the degree of hubbing.