A new identification method is proposed to solve the problem of the influence on the loaded excitation signals brought by high feedback gain augmentation in lateral-directional aerodynamic parameters identification of...A new identification method is proposed to solve the problem of the influence on the loaded excitation signals brought by high feedback gain augmentation in lateral-directional aerodynamic parameters identification of fly-by-wire（FBW） passenger airliners. Taking for example an FBW passenger airliner model with directional relaxed-static-stability, through analysis of its signal energy distribution and airframe frequency response, a new method is proposed for signal type selection, signal parameters design, and the appropriate frequency relationship between the aileron and rudder excitation signals. A simulation validation is presented of the FBW passenger airliner＇s lateral-directional aerodynamic parameters identification. The validation result demonstrates that the designed signal can excite the lateral-directional motion mode of the FBW passenger airliner adequately and persistently. Meanwhile, the relative errors of aerodynamic parameters are less than 5%.展开更多
In this paper,a coupled CFD-CSD method based on N-S equations is described for static aeroelastic correction and jig-shape design of large airliners.The wing structural flexibility matrix is analyzed by a finite eleme...In this paper,a coupled CFD-CSD method based on N-S equations is described for static aeroelastic correction and jig-shape design of large airliners.The wing structural flexibility matrix is analyzed by a finite element method with a double-beam model.The viscous multi-block structured grid is used in aerodynamic calculations.Flexibility matrix interpolation is fulfilled by use of a surface spline method.The load distributions on wing surface are evaluated by solving N-S equations with a parallel algorithm.A flexibility approach is employed to calculate the structural deformations.By successive iterations between steady aerodynamic forces and structural deformations,a coupled CFD-CSD method is achieved for the static aeroelastic correction and jig-shape design of a large airliner.The present method is applied to the static aeroelastic analysis and jig-shape design for a typical large airliner with engine nacelle and winglet.The numerical results indicate that calculations of static aeroelastic correction should employ tightly coupled CFD-CSD iterations,and that on a given cruise shape only one round of iterative design is needed to obtain the jig-shape meeting design requirements.展开更多
African Aviation continues to fall short of serving the demands of the fast-growing African population. For major air transport in and out of the African continent, African travellers rely mainly on non-African Airlin...African Aviation continues to fall short of serving the demands of the fast-growing African population. For major air transport in and out of the African continent, African travellers rely mainly on non-African Airlines. There is, however, one successful airline on the continent at the writing of this paper: Ethiopian Airlines and the Ethiopian Aviation Group. Why are no further successful airlines possible on a continent of 1.4 billion people (25% of the world’s population) and only a 2%-share of global air transport? At the introduction of SAATM, which is anticipated as the start of the domestic African aviation boom, most African countries seem unprepared to build a success story like Ethiopia. Transportation infrastructure in sub-Saharan Africa does not start with roads and rail but with runways and airlines. This research investigates the basic requirements needed to equip Africa with a competitive aviation industry that would contribute some 5% to the continent’s GDP and create hundreds of thousands of workplaces. Interviews with African SAATM leaders signal a slowdown in the effort to succeed. The research is also concerned about the lack of inclusion in the implementation of a NetZero CO2 emission scheme in Africa.展开更多
At the 20th China-ASEAN Expo(CAEXPO)in 2023,Bruneibased airline startup GallopAir signed a letter of intent(LOI)with the Commercial Aircraft Corporation of China(COMAC)for the purchase of 30 aircraft,including the C91...At the 20th China-ASEAN Expo(CAEXPO)in 2023,Bruneibased airline startup GallopAir signed a letter of intent(LOI)with the Commercial Aircraft Corporation of China(COMAC)for the purchase of 30 aircraft,including the C919 jet airliner and the ARJ21(now known as C909)regional jet.展开更多
In the rapidly evolving landscape of natural language processing(NLP)and sentiment analysis,improving the accuracy and efficiency of sentiment classification models is crucial.This paper investigates the performance o...In the rapidly evolving landscape of natural language processing(NLP)and sentiment analysis,improving the accuracy and efficiency of sentiment classification models is crucial.This paper investigates the performance of two advanced models,the Large Language Model(LLM)LLaMA model and NLP BERT model,in the context of airline review sentiment analysis.Through fine-tuning,domain adaptation,and the application of few-shot learning,the study addresses the subtleties of sentiment expressions in airline-related text data.Employing predictive modeling and comparative analysis,the research evaluates the effectiveness of Large Language Model Meta AI(LLaMA)and Bidirectional Encoder Representations from Transformers(BERT)in capturing sentiment intricacies.Fine-tuning,including domain adaptation,enhances the models'performance in sentiment classification tasks.Additionally,the study explores the potential of few-shot learning to improve model generalization using minimal annotated data for targeted sentiment analysis.By conducting experiments on a diverse airline review dataset,the research quantifies the impact of fine-tuning,domain adaptation,and few-shot learning on model performance,providing valuable insights for industries aiming to predict recommendations and enhance customer satisfaction through a deeper understanding of sentiment in user-generated content(UGC).This research contributes to refining sentiment analysis models,ultimately fostering improved customer satisfaction in the airline industry.展开更多
A firm’s profitability is critical to its competitiveness and sustainability. This research looked at the elements that influence airline profitability in Nigeria. From 2005 to 2019, two airlines were picked, and the...A firm’s profitability is critical to its competitiveness and sustainability. This research looked at the elements that influence airline profitability in Nigeria. From 2005 to 2019, two airlines were picked, and their data were retrieved from Nigerian Civil Aviation Authority (NCAA). From estimated quarterly panel data using E-views 8 and SPSS 22, the overall findings of the regression study demonstrate that with ROA used as a proxy for profitability, the R-square is 83.6 per cent and 89.4 per cent, respectively for Aero contractors and Medview airline, representing 83.6 per cent and 89.4 per cent of the changes in profitability of the Aero contractors and Medview in the sample, respectively, could be explained by changes in the study’s independent variables, namely growth, liquidity, leverage, lease, tangibility, fuel cost and personnel cost. Besides the total of the explanatory variables, growth, leverage and tangibility are statically significant at a 5% level of significant Aero Contractors. Growth, leverage, leasing cost, fuel cost, and staff cost, on the other hand, are statistically significant at the 5% level of significance for Medview airlines. Profiteering, expansion, leverage, and tangibility are the primary activities of any airline firm. Lease cost, fuel cost, and staff cost show a statistically significant positive link with the profitability metric ROA. As a result, stakeholders of Nigerian airlines should prioritize profitability over other criteria in this study. Airline executives should do a comprehensive analysis of all potential elements impacting their company’s profitability in the literature, including aspects other than economic variables. According to the findings of this study, political issues account for a greater proportion of the reasons why airlines fail in Nigeria.展开更多
The determination of optimal aerial transport networks and their associated flight frequencies is crucial for the strategic planning of airlines,as well as for carrying out market research,to establish target markets,...The determination of optimal aerial transport networks and their associated flight frequencies is crucial for the strategic planning of airlines,as well as for carrying out market research,to establish target markets,and for aircraft and crew rostering.In addition,optimum airplane types for the selected networks are crucial to improve revenue and to provide reduced operating costs.The present study proposes an innovative approach to determine the optimal aerial transport network simultaneously with the determination of the optimum fleet for that network,composed of three types of airplanes(network and vehicle integrated design).The network profit is maximized.The passenger’s demands between the airports are determined via a gravitational model.An embedded linear programming solution is responsible for obtaining potential optimal network configurations.The optimum fleet combination is determined from a database of candidate aircraft designs via genetic algorithm.A truly realistic airplane representation is made possible thanks to accurate surrogate models for engine and aerodynamics is adopted.An accurate engine deck encompassing a compression map and an innovative engine weight calculation besides an aerodynamical artificial neural network module enable a high degree of accuracy for the mission analysis.The proposed methodology is applied to obtain the optimum network comprised of twenty main Brazilian airports and corresponding fleet.展开更多
Analysis of the Direct Operating Cost(DOC) of aircraft is an important step towards achieving financially sustainable aviation operations. However, the value of the DOC for different aircraft types and flight scenario...Analysis of the Direct Operating Cost(DOC) of aircraft is an important step towards achieving financially sustainable aviation operations. However, the value of the DOC for different aircraft types and flight scenarios is not widely available. In this study, we perform a systematic analysis of the DOC of every wide-body passenger aircraft currently in production, using the method of the Association of European Airlines(AEA). The elements of the DOC, e.g. financial costs, maintenance costs, and flight costs, are evaluated individually. Several realistic flight scenarios are considered, each with differences in route distance, fuel price, passenger number, and seating arrangement. For each flight scenario, the most cost-efficient aircraft type is identified and evaluated in the context of operations from Hong Kong International Airport. The information provided in this study could be useful to airline operators and policy makers.展开更多
Almost half of all flight accidents caused by inflight icing occur at the approach and landing phases when high-lift devices are deployed.The present study focuses on the optimization of an ice-tolerant multi-element ...Almost half of all flight accidents caused by inflight icing occur at the approach and landing phases when high-lift devices are deployed.The present study focuses on the optimization of an ice-tolerant multi-element airfoil.Dual-objective optimization is carried out with critical hornshaped ice accumulated during the holding phase.The optimization results show that the present optimization method significantly enhances the iced-state and clean-state performance.The optimal multi-element airfoil has a larger deflection angle and wider gap at the slat and the flap compared with the baseline configuration.The sensitivity of each design parameter is analyzed,which verifies the robustness of the design.The design is further assessed when ice is accreted during the approach and landing phases,which also shows performance improvement.展开更多
It is common that airlines encounter a disruption of a flight schedule,which is mainly caused by resource shortages.In case of a disruption,subject to scarce resources,most of airlines lose flexibility of performing a...It is common that airlines encounter a disruption of a flight schedule,which is mainly caused by resource shortages.In case of a disruption,subject to scarce resources,most of airlines lose flexibility of performing aircraft recovery on the basis of business interest priorities and need to delay,swap,and cancel flights.This paper proposes an air-rail inter-modal strategy to incorporate a High-Speed Rail(HSR)transport mode into an aviation network for aircraft recovery.The air-rail inter-modal strategy focuses on occasionally operational integration of existing airside and HSR infrastructure capacities.It is different from air-rail cooperation implemented in Europe which emphasizes a long-term strategy.In addition to modelling the air-rail inter-modal strategy,an inter-modal time-band network is presented.Modelling is applied to a pure aviation network and the inter-modal network.Comparison results show that the inter-modal air-rail strategy helps to reduce the number of cancelled flights and the total disruption cost.展开更多
To enhance the accuracy of performance analysis of regional airline network,this study applies complex network theory and Density-Based Spatial Clustering of Applications with Noise(DBSCAN)algorithm to investigate the...To enhance the accuracy of performance analysis of regional airline network,this study applies complex network theory and Density-Based Spatial Clustering of Applications with Noise(DBSCAN)algorithm to investigate the topology of regional airline network,constructs node importance index system,and clusters 161 airport nodes of regional airline network.Besides,entropy power method and approximating ideal solution method(TOPSIS)is applied to comprehensively evaluate the importance of airport nodes and complete the classification of nodes and identification of key points;adopt network efficiency,maximum connectivity subgraph and network connectivity as vulnerability measurement indexes,and observe the changes of vulnerability indexes of key nodes under deliberate attacks and 137 nodes under random attacks.The results demonstrate that the decreasing trend of the maximum connectivity subgraph indicator is slower and the decreasing trend of the network efficiency and connectivity indicators is faster when the critical nodes of the regional airline network are deliberately attacked.Besides,the decreasing trend of the network efficiency indicator is faster and the decreasing trend of the maximum connectivity subgraph indicator is slower when the nodes of four different categories are randomly attacked.Finally,it is proposed to identify and focus on protecting critical nodes in order to better improve the security level of regional airline system.展开更多
When disruptions occur, the airlines have to recover from the disrupted schedule. The recovery usually consists of aircraft recovery, crew recovery and passengers' recovery. This paper focuses on the integrated re...When disruptions occur, the airlines have to recover from the disrupted schedule. The recovery usually consists of aircraft recovery, crew recovery and passengers' recovery. This paper focuses on the integrated recovery, which means above-mentioned two or more recoveries are considered as a whole. Taking the minimization of the total cost of assignment, cancellation and delay as an objective, we present a more practical model, in which the maintenance and the union regulations are considered. Then we present a so-called iterative tree growing with node combination method. By aggregating nodes, the possibility of routings is greatly simplified, and the computation time is greatly decreased. By adjusting the consolidating range, the computation time can be controlled in a reasonable time. Finally, we use data from a main Chinese airline to test the algorithm. The experimental results show that this method could be used in the integrated recovery problem.展开更多
The airlines need to select the optional equipment according to their individual development demands and the manufacture′s standard specification manual when purchasing a new airplane.For this customization process,t...The airlines need to select the optional equipment according to their individual development demands and the manufacture′s standard specification manual when purchasing a new airplane.For this customization process,the selection theory is mainly based on qualitative analysis and quantitative analysis.The grey incidence analysis(GIA)is used for modeling,which evaluates the correlations between optional equipment and airlines′individual demands.Meanwhile,the customization demands are quantitatively processed as different weights in evaluation index system with analytical hierarchy process.Then,the value of grey incidence degree is obtained which shows whether the optional equipment is on the purchasing list or not.Finally,two airlines′customization demands are applied in the example of aircraft cabin′s seats,so two different purchasing priorities and equipment installation lists can be obtained.The results and comparisons verify the reasonable of modeling,which provides an objective scheme of aircraft equipment selection.展开更多
Aircraft on ground or down-time for its maintenance is a clear loss in revenue for an airline operation. With never ending competition and growing operating costs of aircraft, airlines continuously need to explore opp...Aircraft on ground or down-time for its maintenance is a clear loss in revenue for an airline operation. With never ending competition and growing operating costs of aircraft, airlines continuously need to explore opportunities to reduce the aircraft down-time in order to remain sustainable. Due to round the clock operation feature of scheduled airlines, aircraft maintenance operations are generally carried out using traditional management methodologies instead of considering it as a project. Though aircraft heavy maintenance checks consist of several major tasks that can last from few weeks to a year, the maintenance organisations do not adopt modern project management methodologies. Therefore, this paper models a heavy maintenance check of an Airbus aircraft as a typical project and adopts contemporary project management methodology to explore the possibility of reducing the downtime. To this end, a case study has been done at an aircraft maintenance company to analyse the potential of this project management method in aircraft maintenance industry.展开更多
This study analyzed the potential impact of the increased oil volatility on the industries and the global economy. Specifically, it separated the oil price fluctuations into positive and negative components, and model...This study analyzed the potential impact of the increased oil volatility on the industries and the global economy. Specifically, it separated the oil price fluctuations into positive and negative components, and modeled the return of industry portfolios with them. Next, the sensitivity of the airline industry to oil price was investigated to gauge the effectiveness of their hedging strategies, with the hope that the methodology can be extended to other industries. In addition, this paper explored the macroeconomic impact of oil price movements by examining the benchmarks such as GDP and CPI.展开更多
We study cooperation between the airline and high-speed rail(HSR) sectors by formulating their joint profit as a maximization problem using a multinomial logit choice model in a three-node setting. We allow the nonpur...We study cooperation between the airline and high-speed rail(HSR) sectors by formulating their joint profit as a maximization problem using a multinomial logit choice model in a three-node setting. We allow the nonpurchase option as an outside option available to consumers. The demand for each choice is not only a function of the price but also the service quality, such as the total trip time, frequency of service, and ease of connecting from the hub to a nearby HSR station. As a result, the following findings are presented. First, regardless of the service quality of either sector and the non-purchase option,cooperation decreases the total volume of the domestic market of a country. Second, when the attractiveness of the outside option is high, the HSR and air sectors can prevent a large reduction in the total volume by cooperation in the connecting market. However, this is not the case in the domestic market. Third, if the non-purchase quality in the domestic market is high, then cooperation increases the social welfare of the whole market. If the non-purchase quality is low, then cooperation increases the welfare of the whole market only in cases where the number of potential customers in the connecting market is relatively large. We also show the effect of improving air–rail service quality on each market share and on the total profit.展开更多
Crew pairing is a sequence of flights beginning and ending at the same crewbase. Crew pairing planning is one of the primary processes in airline crew scheduling;it is also the primary cost-determining phase in airlin...Crew pairing is a sequence of flights beginning and ending at the same crewbase. Crew pairing planning is one of the primary processes in airline crew scheduling;it is also the primary cost-determining phase in airline crew scheduling. Optimizing crew pairings in an airline timetable helps minimize operational crew costs and maximize crew utilization. There are numerous restrictions that must be considered and just as many regulations that must be satisfied in crew pairing generation. The most important regulations—and the ones that make crew pairing planning a highly constrained optimization problem—are the the limits of the flight and the duty periods. Keeping these restrictions and regulations in mind, the main goal of the optimization is the generation of low cost sets of valid crew pairings which cover all flights in the airline’s timetable. For this research study, We examined studies about crew pairing optimization and used these previously existing methods of crew pairing to develop a new solution of the crew pairing problem using genetic algorithms. As part of the study we created a new genetic operator—called perturbation operator.Unlike traditional genetic algorithm implementations, this new perturbation operator provides much more stable results, an obvious increase in the convergence rate, and takes into account the existence of multiple crewbases.展开更多
This paper studies airline partner selection.The international airline operation involves considerable cooperations with other airlines at home and abroad.How to choose the most suitable partners is a realistic issue ...This paper studies airline partner selection.The international airline operation involves considerable cooperations with other airlines at home and abroad.How to choose the most suitable partners is a realistic issue for Chinese airlines.In this paper the quality of service index(QSI)model is improved by applying more necessary indexes based on the analysis of large scale of data.A partner selection model is established to help airlines identify the best partner(s)in a scientific and effective way among potential candidates.Finally,real data from an airline company in China is applied to test the model.The outcome verify the effectiveness of the partner selection model proposed in this paper.The model can be helpful for selecting more suitable partners and increasing coordination value through cooperation with the partners.展开更多
Considering the existence of multi-level fares in the alliance,and the existence of horizontal competition and vertical competition at the same time,this paper intends to maximize the revenue of airline alliance and f...Considering the existence of multi-level fares in the alliance,and the existence of horizontal competition and vertical competition at the same time,this paper intends to maximize the revenue of airline alliance and fairly distribute the revenue to member airlines.Firstly,a model is built under the centralized mechanism,in which all airlines in the alliance are regarded as a whole.By solving the model,the shadow price of each flight leg on the code-sharing route is gotten.It is used to calculate the proportion of the revenue distribution.Then,the centralized model is decomposed into the single airline model by the proportion.The seat allocation among airlines and distributed revenue can be gotten by solving the model.Three typical examples are designed to test it.The results show that,the model can effectively reflect the managerial principal of the airline alliance,that is maximizing total revenue and fairly distributing the revenue among member airlines.展开更多
文摘A new identification method is proposed to solve the problem of the influence on the loaded excitation signals brought by high feedback gain augmentation in lateral-directional aerodynamic parameters identification of fly-by-wire（FBW） passenger airliners. Taking for example an FBW passenger airliner model with directional relaxed-static-stability, through analysis of its signal energy distribution and airframe frequency response, a new method is proposed for signal type selection, signal parameters design, and the appropriate frequency relationship between the aileron and rudder excitation signals. A simulation validation is presented of the FBW passenger airliner＇s lateral-directional aerodynamic parameters identification. The validation result demonstrates that the designed signal can excite the lateral-directional motion mode of the FBW passenger airliner adequately and persistently. Meanwhile, the relative errors of aerodynamic parameters are less than 5%.
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘In this paper,a coupled CFD-CSD method based on N-S equations is described for static aeroelastic correction and jig-shape design of large airliners.The wing structural flexibility matrix is analyzed by a finite element method with a double-beam model.The viscous multi-block structured grid is used in aerodynamic calculations.Flexibility matrix interpolation is fulfilled by use of a surface spline method.The load distributions on wing surface are evaluated by solving N-S equations with a parallel algorithm.A flexibility approach is employed to calculate the structural deformations.By successive iterations between steady aerodynamic forces and structural deformations,a coupled CFD-CSD method is achieved for the static aeroelastic correction and jig-shape design of a large airliner.The present method is applied to the static aeroelastic analysis and jig-shape design for a typical large airliner with engine nacelle and winglet.The numerical results indicate that calculations of static aeroelastic correction should employ tightly coupled CFD-CSD iterations,and that on a given cruise shape only one round of iterative design is needed to obtain the jig-shape meeting design requirements.
文摘African Aviation continues to fall short of serving the demands of the fast-growing African population. For major air transport in and out of the African continent, African travellers rely mainly on non-African Airlines. There is, however, one successful airline on the continent at the writing of this paper: Ethiopian Airlines and the Ethiopian Aviation Group. Why are no further successful airlines possible on a continent of 1.4 billion people (25% of the world’s population) and only a 2%-share of global air transport? At the introduction of SAATM, which is anticipated as the start of the domestic African aviation boom, most African countries seem unprepared to build a success story like Ethiopia. Transportation infrastructure in sub-Saharan Africa does not start with roads and rail but with runways and airlines. This research investigates the basic requirements needed to equip Africa with a competitive aviation industry that would contribute some 5% to the continent’s GDP and create hundreds of thousands of workplaces. Interviews with African SAATM leaders signal a slowdown in the effort to succeed. The research is also concerned about the lack of inclusion in the implementation of a NetZero CO2 emission scheme in Africa.
文摘At the 20th China-ASEAN Expo(CAEXPO)in 2023,Bruneibased airline startup GallopAir signed a letter of intent(LOI)with the Commercial Aircraft Corporation of China(COMAC)for the purchase of 30 aircraft,including the C919 jet airliner and the ARJ21(now known as C909)regional jet.
文摘In the rapidly evolving landscape of natural language processing(NLP)and sentiment analysis,improving the accuracy and efficiency of sentiment classification models is crucial.This paper investigates the performance of two advanced models,the Large Language Model(LLM)LLaMA model and NLP BERT model,in the context of airline review sentiment analysis.Through fine-tuning,domain adaptation,and the application of few-shot learning,the study addresses the subtleties of sentiment expressions in airline-related text data.Employing predictive modeling and comparative analysis,the research evaluates the effectiveness of Large Language Model Meta AI(LLaMA)and Bidirectional Encoder Representations from Transformers(BERT)in capturing sentiment intricacies.Fine-tuning,including domain adaptation,enhances the models'performance in sentiment classification tasks.Additionally,the study explores the potential of few-shot learning to improve model generalization using minimal annotated data for targeted sentiment analysis.By conducting experiments on a diverse airline review dataset,the research quantifies the impact of fine-tuning,domain adaptation,and few-shot learning on model performance,providing valuable insights for industries aiming to predict recommendations and enhance customer satisfaction through a deeper understanding of sentiment in user-generated content(UGC).This research contributes to refining sentiment analysis models,ultimately fostering improved customer satisfaction in the airline industry.
文摘A firm’s profitability is critical to its competitiveness and sustainability. This research looked at the elements that influence airline profitability in Nigeria. From 2005 to 2019, two airlines were picked, and their data were retrieved from Nigerian Civil Aviation Authority (NCAA). From estimated quarterly panel data using E-views 8 and SPSS 22, the overall findings of the regression study demonstrate that with ROA used as a proxy for profitability, the R-square is 83.6 per cent and 89.4 per cent, respectively for Aero contractors and Medview airline, representing 83.6 per cent and 89.4 per cent of the changes in profitability of the Aero contractors and Medview in the sample, respectively, could be explained by changes in the study’s independent variables, namely growth, liquidity, leverage, lease, tangibility, fuel cost and personnel cost. Besides the total of the explanatory variables, growth, leverage and tangibility are statically significant at a 5% level of significant Aero Contractors. Growth, leverage, leasing cost, fuel cost, and staff cost, on the other hand, are statistically significant at the 5% level of significance for Medview airlines. Profiteering, expansion, leverage, and tangibility are the primary activities of any airline firm. Lease cost, fuel cost, and staff cost show a statistically significant positive link with the profitability metric ROA. As a result, stakeholders of Nigerian airlines should prioritize profitability over other criteria in this study. Airline executives should do a comprehensive analysis of all potential elements impacting their company’s profitability in the literature, including aspects other than economic variables. According to the findings of this study, political issues account for a greater proportion of the reasons why airlines fail in Nigeria.
文摘The determination of optimal aerial transport networks and their associated flight frequencies is crucial for the strategic planning of airlines,as well as for carrying out market research,to establish target markets,and for aircraft and crew rostering.In addition,optimum airplane types for the selected networks are crucial to improve revenue and to provide reduced operating costs.The present study proposes an innovative approach to determine the optimal aerial transport network simultaneously with the determination of the optimum fleet for that network,composed of three types of airplanes(network and vehicle integrated design).The network profit is maximized.The passenger’s demands between the airports are determined via a gravitational model.An embedded linear programming solution is responsible for obtaining potential optimal network configurations.The optimum fleet combination is determined from a database of candidate aircraft designs via genetic algorithm.A truly realistic airplane representation is made possible thanks to accurate surrogate models for engine and aerodynamics is adopted.An accurate engine deck encompassing a compression map and an innovative engine weight calculation besides an aerodynamical artificial neural network module enable a high degree of accuracy for the mission analysis.The proposed methodology is applied to obtain the optimum network comprised of twenty main Brazilian airports and corresponding fleet.
文摘Analysis of the Direct Operating Cost(DOC) of aircraft is an important step towards achieving financially sustainable aviation operations. However, the value of the DOC for different aircraft types and flight scenarios is not widely available. In this study, we perform a systematic analysis of the DOC of every wide-body passenger aircraft currently in production, using the method of the Association of European Airlines(AEA). The elements of the DOC, e.g. financial costs, maintenance costs, and flight costs, are evaluated individually. Several realistic flight scenarios are considered, each with differences in route distance, fuel price, passenger number, and seating arrangement. For each flight scenario, the most cost-efficient aircraft type is identified and evaluated in the context of operations from Hong Kong International Airport. The information provided in this study could be useful to airline operators and policy makers.
基金supported by the National Key Project of China(No.GJXM92579)National Natural Science Foundation of China(Nos.92052203,11872230 and 91852108)。
文摘Almost half of all flight accidents caused by inflight icing occur at the approach and landing phases when high-lift devices are deployed.The present study focuses on the optimization of an ice-tolerant multi-element airfoil.Dual-objective optimization is carried out with critical hornshaped ice accumulated during the holding phase.The optimization results show that the present optimization method significantly enhances the iced-state and clean-state performance.The optimal multi-element airfoil has a larger deflection angle and wider gap at the slat and the flap compared with the baseline configuration.The sensitivity of each design parameter is analyzed,which verifies the robustness of the design.The design is further assessed when ice is accreted during the approach and landing phases,which also shows performance improvement.
基金co-supported by the Tianjin Natural Science Foundation, China (No. 18JCQNJC04300)the National Natural Science Foundation of China (No. 71801215)the Foundation for University Key Teacher by the Ministry of Education of China (Nos. 3122018C033, 3122015L010)
文摘It is common that airlines encounter a disruption of a flight schedule,which is mainly caused by resource shortages.In case of a disruption,subject to scarce resources,most of airlines lose flexibility of performing aircraft recovery on the basis of business interest priorities and need to delay,swap,and cancel flights.This paper proposes an air-rail inter-modal strategy to incorporate a High-Speed Rail(HSR)transport mode into an aviation network for aircraft recovery.The air-rail inter-modal strategy focuses on occasionally operational integration of existing airside and HSR infrastructure capacities.It is different from air-rail cooperation implemented in Europe which emphasizes a long-term strategy.In addition to modelling the air-rail inter-modal strategy,an inter-modal time-band network is presented.Modelling is applied to a pure aviation network and the inter-modal network.Comparison results show that the inter-modal air-rail strategy helps to reduce the number of cancelled flights and the total disruption cost.
文摘To enhance the accuracy of performance analysis of regional airline network,this study applies complex network theory and Density-Based Spatial Clustering of Applications with Noise(DBSCAN)algorithm to investigate the topology of regional airline network,constructs node importance index system,and clusters 161 airport nodes of regional airline network.Besides,entropy power method and approximating ideal solution method(TOPSIS)is applied to comprehensively evaluate the importance of airport nodes and complete the classification of nodes and identification of key points;adopt network efficiency,maximum connectivity subgraph and network connectivity as vulnerability measurement indexes,and observe the changes of vulnerability indexes of key nodes under deliberate attacks and 137 nodes under random attacks.The results demonstrate that the decreasing trend of the maximum connectivity subgraph indicator is slower and the decreasing trend of the network efficiency and connectivity indicators is faster when the critical nodes of the regional airline network are deliberately attacked.Besides,the decreasing trend of the network efficiency indicator is faster and the decreasing trend of the maximum connectivity subgraph indicator is slower when the nodes of four different categories are randomly attacked.Finally,it is proposed to identify and focus on protecting critical nodes in order to better improve the security level of regional airline system.
文摘When disruptions occur, the airlines have to recover from the disrupted schedule. The recovery usually consists of aircraft recovery, crew recovery and passengers' recovery. This paper focuses on the integrated recovery, which means above-mentioned two or more recoveries are considered as a whole. Taking the minimization of the total cost of assignment, cancellation and delay as an objective, we present a more practical model, in which the maintenance and the union regulations are considered. Then we present a so-called iterative tree growing with node combination method. By aggregating nodes, the possibility of routings is greatly simplified, and the computation time is greatly decreased. By adjusting the consolidating range, the computation time can be controlled in a reasonable time. Finally, we use data from a main Chinese airline to test the algorithm. The experimental results show that this method could be used in the integrated recovery problem.
文摘The airlines need to select the optional equipment according to their individual development demands and the manufacture′s standard specification manual when purchasing a new airplane.For this customization process,the selection theory is mainly based on qualitative analysis and quantitative analysis.The grey incidence analysis(GIA)is used for modeling,which evaluates the correlations between optional equipment and airlines′individual demands.Meanwhile,the customization demands are quantitatively processed as different weights in evaluation index system with analytical hierarchy process.Then,the value of grey incidence degree is obtained which shows whether the optional equipment is on the purchasing list or not.Finally,two airlines′customization demands are applied in the example of aircraft cabin′s seats,so two different purchasing priorities and equipment installation lists can be obtained.The results and comparisons verify the reasonable of modeling,which provides an objective scheme of aircraft equipment selection.
文摘Aircraft on ground or down-time for its maintenance is a clear loss in revenue for an airline operation. With never ending competition and growing operating costs of aircraft, airlines continuously need to explore opportunities to reduce the aircraft down-time in order to remain sustainable. Due to round the clock operation feature of scheduled airlines, aircraft maintenance operations are generally carried out using traditional management methodologies instead of considering it as a project. Though aircraft heavy maintenance checks consist of several major tasks that can last from few weeks to a year, the maintenance organisations do not adopt modern project management methodologies. Therefore, this paper models a heavy maintenance check of an Airbus aircraft as a typical project and adopts contemporary project management methodology to explore the possibility of reducing the downtime. To this end, a case study has been done at an aircraft maintenance company to analyse the potential of this project management method in aircraft maintenance industry.
文摘This study analyzed the potential impact of the increased oil volatility on the industries and the global economy. Specifically, it separated the oil price fluctuations into positive and negative components, and modeled the return of industry portfolios with them. Next, the sensitivity of the airline industry to oil price was investigated to gauge the effectiveness of their hedging strategies, with the hope that the methodology can be extended to other industries. In addition, this paper explored the macroeconomic impact of oil price movements by examining the benchmarks such as GDP and CPI.
基金funding support from a JSPS Grant-in-Aid for Young Scientists (B) (26870643)funding support from a JSPS fellowship in 2013–2014 during his sabbatical at the National Graduate Institute for Policy Studies,Japan
文摘We study cooperation between the airline and high-speed rail(HSR) sectors by formulating their joint profit as a maximization problem using a multinomial logit choice model in a three-node setting. We allow the nonpurchase option as an outside option available to consumers. The demand for each choice is not only a function of the price but also the service quality, such as the total trip time, frequency of service, and ease of connecting from the hub to a nearby HSR station. As a result, the following findings are presented. First, regardless of the service quality of either sector and the non-purchase option,cooperation decreases the total volume of the domestic market of a country. Second, when the attractiveness of the outside option is high, the HSR and air sectors can prevent a large reduction in the total volume by cooperation in the connecting market. However, this is not the case in the domestic market. Third, if the non-purchase quality in the domestic market is high, then cooperation increases the social welfare of the whole market. If the non-purchase quality is low, then cooperation increases the welfare of the whole market only in cases where the number of potential customers in the connecting market is relatively large. We also show the effect of improving air–rail service quality on each market share and on the total profit.
文摘Crew pairing is a sequence of flights beginning and ending at the same crewbase. Crew pairing planning is one of the primary processes in airline crew scheduling;it is also the primary cost-determining phase in airline crew scheduling. Optimizing crew pairings in an airline timetable helps minimize operational crew costs and maximize crew utilization. There are numerous restrictions that must be considered and just as many regulations that must be satisfied in crew pairing generation. The most important regulations—and the ones that make crew pairing planning a highly constrained optimization problem—are the the limits of the flight and the duty periods. Keeping these restrictions and regulations in mind, the main goal of the optimization is the generation of low cost sets of valid crew pairings which cover all flights in the airline’s timetable. For this research study, We examined studies about crew pairing optimization and used these previously existing methods of crew pairing to develop a new solution of the crew pairing problem using genetic algorithms. As part of the study we created a new genetic operator—called perturbation operator.Unlike traditional genetic algorithm implementations, this new perturbation operator provides much more stable results, an obvious increase in the convergence rate, and takes into account the existence of multiple crewbases.
基金supported by the Civil Aviation Science and Technology Innovation Guide Funding Project of China(No.MHRD20140307)Project of Philosophy and Social Science Research in Colleges and Universities of Jiangsu Province,China(No.2014SJB010)
文摘This paper studies airline partner selection.The international airline operation involves considerable cooperations with other airlines at home and abroad.How to choose the most suitable partners is a realistic issue for Chinese airlines.In this paper the quality of service index(QSI)model is improved by applying more necessary indexes based on the analysis of large scale of data.A partner selection model is established to help airlines identify the best partner(s)in a scientific and effective way among potential candidates.Finally,real data from an airline company in China is applied to test the model.The outcome verify the effectiveness of the partner selection model proposed in this paper.The model can be helpful for selecting more suitable partners and increasing coordination value through cooperation with the partners.
基金partially supported by the Natural Science Foundation of Jiangsu Province(No.BK 20151479)the Central University Basic Research Fees(No.NZ2016109)
文摘Considering the existence of multi-level fares in the alliance,and the existence of horizontal competition and vertical competition at the same time,this paper intends to maximize the revenue of airline alliance and fairly distribute the revenue to member airlines.Firstly,a model is built under the centralized mechanism,in which all airlines in the alliance are regarded as a whole.By solving the model,the shadow price of each flight leg on the code-sharing route is gotten.It is used to calculate the proportion of the revenue distribution.Then,the centralized model is decomposed into the single airline model by the proportion.The seat allocation among airlines and distributed revenue can be gotten by solving the model.Three typical examples are designed to test it.The results show that,the model can effectively reflect the managerial principal of the airline alliance,that is maximizing total revenue and fairly distributing the revenue among member airlines.
