Search results
1 – 10 of over 3000Wu Deng, Meng Sun, Huimin Zhao, Bo Li and Chunxiao Wang
This study aims to propose a new airport gate assignment method to effectively improve the comprehensive operation capacity and efficiency of hub airport. Gate assignment is one…
Abstract
Purpose
This study aims to propose a new airport gate assignment method to effectively improve the comprehensive operation capacity and efficiency of hub airport. Gate assignment is one of the most important tasks for airport ground operations, which assigns appropriate airport gates with high efficiency reasonable arrangement.
Design/methodology/approach
In this paper, on the basis of analyzing the characteristics of airport gates and flights, an efficient multi-objective optimization model of airport gate assignment based on the objectives of the most balanced idle time, the shortest walking distances of passengers and the least number of flights at apron is constructed. Then an improved ant colony optimization (ICQACO) algorithm based on the ant colony collaborative strategy and pheromone update strategy is designed to solve the constructed model to fast realize the gate assignment and obtain a rational and effective gate assignment result for all flights in the different period.
Findings
In the designed ICQACO algorithm, the ant colony collaborative strategy is used to avoid the rapid convergence to the local optimal solution, and the pheromone update strategy is used to quickly increase the pheromone amount, eliminate the interference of the poor path and greatly accelerate the convergence speed.
Practical implications
The actual flight data from Guangzhou Baiyun airport of China is selected to verify the feasibility and effectiveness of the constructed multi-objective optimization model and the designed ICQACO algorithm. The experimental results show that the designed ICQACO algorithm can increase the pheromone amount, accelerate the convergence speed and avoid to fall into the local optimal solution. The constructed multi-objective optimization model can effectively improve the comprehensive operation capacity and efficiency. This study is a very meaningful work for airport gate assignment.
Originality/value
An efficient multi-objective optimization model for hub airport gate assignment problem is proposed in this paper. An improved ant colony optimization algorithm based on ant colony collaborative strategy and the pheromone update strategy is deeply studied to speed up the convergence and avoid to fall into the local optimal solution.
Details
Keywords
Marvin Gonzalez and Gioconda Quesada
The productivity of a port is a measure that is important to different stakeholders: port administrators (port authority), third-party logistics providers, manufacturers and…
Abstract
Purpose
The productivity of a port is a measure that is important to different stakeholders: port administrators (port authority), third-party logistics providers, manufacturers and consumers, among others. This study analyses productivity in terms of vessel movement efficiencies (loading/unloading of cargo) and container release from port facilities. Both factors add to the overall productivity in any port.
Design/methodology/approach
A comparative analysis of the productivity of three ports is measured using a Quality Function Deployment (QFD) and benchmarking analysis to help establish strategies that will help improve productivity. Considering the information confidentially the authors will call the ports according to their geographic location. The ports under study are the USA Southeast Port (Port of America), Central Asian Port (Port of Asia) and Central Europe Port (Port of Europe).
Findings
This study has established an analysis strategy that allows seeing points of sale in the ports. This study will compare three different continents, only to demonstrate the applicability of QFD and benchmarking. Still, the strategy can be used in ports that compete due to their proximity and location. Identifying the variables to be analyzed made it possible to establish a strategy to increase productivity.
Originality/value
There are many studies that analyze port productivity, but none try to standardize the variables to be compared in different scenarios. This study has compared three ports from three different geographical areas, using the same variables in all three cases. The study critically analyses the performance of three ports and proposes a strategy based on QFD and benchmarking research.
Details
Keywords
Bahareh Shafipour-Omrani, Alireza Rashidi Komijan, Seyed Jafar Sadjadi, Kaveh Khalili-Damghani and Vahidreza Ghezavati
One of the main advantages of the proposed model is that it is flexible to generate n-day pairings simultaneously. It means that, despite previous researches, one-day to n-day…
Abstract
Purpose
One of the main advantages of the proposed model is that it is flexible to generate n-day pairings simultaneously. It means that, despite previous researches, one-day to n-day pairings can be generated in a single model. The flexibility in generating parings causes that the proposed model leads to better solutions compared to existing models. Another advantage of the model is minimizing the risk of COVID-19 by limitation of daily flights as well as elapsed time minimization. As airports are among high risk places in COVID-19 pandemic, minimization of infection risk is considered in this model for the first time. Genetic algorithm is used as the solution approach, and its efficiency is compared to GAMS in small and medium-size problems.
Design/methodology/approach
One of the most complex issues in airlines is crew scheduling problem which is divided into two subproblems: crew pairing problem (CPP) and crew rostering problem (CRP). Generating crew pairings is a tremendous and exhausting task as millions of pairings may be generated for an airline. Moreover, crew cost has the largest share in total cost of airlines after fuel cost. As a result, crew scheduling with the aim of cost minimization is one of the most important issues in airlines. In this paper, a new bi-objective mixed integer programming model is proposed to generate pairings in such a way that deadhead cost, crew cost and the risk of COVID-19 are minimized.
Findings
The proposed model is applied for domestic flights of Iran Air airline. The results of the study indicate that genetic algorithm solutions have only 0.414 and 0.380 gap on average to optimum values of the first and the second objective functions, respectively. Due to the flexibility of the proposed model, it improves solutions resulted from existing models with fixed-duty pairings. Crew cost is decreased by 12.82, 24.72, 4.05 and 14.86% compared to one-duty to four-duty models. In detail, crew salary is improved by 12.85, 24.64, 4.07 and 14.91% and deadhead cost is decreased by 11.87, 26.98, 3.27, and 13.35% compared to one-duty to four-duty models, respectively.
Originality/value
The authors confirm that it is an original paper, has not been published elsewhere and is not currently under consideration of any other journal.
Details
Keywords
Milton Vieira Junior, Wagner Cezar Lucato, Rosangela Maria Vanalle and Kalinga Jagoda
The Brazilian textile industry has been facing fierce competition from low-cost imports from China and other Far East countries. To maintain their competitiveness in the local…
Abstract
Purpose
The Brazilian textile industry has been facing fierce competition from low-cost imports from China and other Far East countries. To maintain their competitiveness in the local market, Brazilian companies have been adopting the product differentiation strategy. By using new technologies, they are able to develop new products with better quality at lower costs. With regard to new technologies, companies in the Brazilian textile industry have been using get-some and buy-some strategy, and international technology transfer (TT) has become an important part of their business strategies. However, due to lack of planning, many projects failed to achieve the desired results. This paper aims to provide theoretical insights and practical guidance on how textile firms could use a stage-gate model to enhance the effectiveness of their TT projects.
Design/methodology/approach
In order to investigate the TT practices in the Brazilian context, three issues are assessed. First, the paper evaluates the possibility of deploying TT practices used by firms in similar industries, to enhance the effectiveness of TT process. Second, it verifies whether it is possible for the textile firms to use a stage-gate model to manage their TT processes, using as a normative framework the stage-gate model proposed by Jagoda and Ramanathan and Jagoda et al. Finally, possible changes to the stage-gate model are evaluated to specifically fit the Brazilian textile sector. This step is accomplished through four case studies from the Brazilian textile industry.
Findings
The analyses of TT projects carried out by four companies show that there are many similarities and differences among the TT practices that are employed by the four companies that were investigated. The evaluation of the TT practices of the Brazilian textile companies against the stage-gate framework allowed authors to identify the gaps between the model and the TT practices of the companies investigated. Broader guidelines in adapting the stage-gate model to improve the TT process in the textile industry are discussed in the final part of this study.
Originality/value
The TT process in the Brazilian textile industry is not a widely investigated phenomenon; however, this process has been critical to enhancing Brazil's competitiveness. Thus, providing a better framework to support the TT process in the local textile sector could be relevant information for improving management action in the area.
Details
Keywords
Ivan Stevovic, Jovana Jovanovic and Svetlana Stevovic
The purpose of this paper is to analyze sustainability of the constructed projects (Djerdap 1 and 2) and feasibility of the planned ones (Djerdap 3) on the river Danube in the…
Abstract
Purpose
The purpose of this paper is to analyze sustainability of the constructed projects (Djerdap 1 and 2) and feasibility of the planned ones (Djerdap 3) on the river Danube in the region of Iron Gate, with multi-criteria focus on technical, economical and environmental parameters.
Design/methodology/approach
The main objectives were achieved by using the methodology of a holistic multi-criteria approach. Electra method was applied. The design of the three projects on the international Danube River were analyzed, from technical, economical and environmental point of view, with the goal to manage a higher involvement of renewable resources.
Findings
The results of the research imply that the most profitable technical solutions cannot reach its realization and construction if the environmental quality criteria are not fulfilled and included in the multi-criteria optimization model. At the same time, the most sustainable and environmentally friendly technical solutions, such as the renewable hydro pump storage scheme, cannot be realized without proper project management and investment.
Research limitations/implications
The results and conclusions are valid for all the structures and projects of renewable resources, where there is a conflict to the environment. This research has implications to all decision-making processes focusing on holistic analyses of conflicted techno-economical and environmental parameters.
Originality/value
The value of the paper and research is in proving the necessity of simultaneous analyses of technical, economical and environmental impacts on the projects. All the results of the research are beneficial for stakeholders who intend to invest in renewable hydro energy resources, in the function of sustainable development.
Details
Keywords
Jing Wang, Nathan N. Huynh and Edsel Pena
This paper evaluates an alternative queuing concept for marine container terminals that utilize a truck appointment system (TAS). Instead of having all lanes providing service to…
Abstract
Purpose
This paper evaluates an alternative queuing concept for marine container terminals that utilize a truck appointment system (TAS). Instead of having all lanes providing service to trucks with appointments, this study considers the case where walk-in lanes are provided to serve those trucks with no appointments or trucks with appointments but arrived late due to traffic congestion.
Design/methodology/approach
To enable the analysis of the proposed alternative queuing strategy, the queuing system is shown mathematically to be stationary. Due to the complexity of the model, a discrete event simulation (DES) model is used to obtain the average waiting number of trucks per lane for both types of service lanes: TAS-lanes and walk-in lanes.
Findings
The numerical experiment results indicated that the considered queuing strategy is most beneficial when the utilization of the TAS lanes is expected to be much higher than that of the walk-in lanes.
Originality/value
The novelty of this study is that it examines the scenario where trucks with appointments switch to the walk-in lanes upon arrival if the TAS-lane server is occupied and the walk-in lane server is not occupied. This queuing strategy/policy could reduce the average waiting time of trucks at marine container terminals. Approximation equations are provided to assist practitioners calculate the average truck queue length and the average truck queuing time for this type of queuing system.
Details
Keywords
Saeid Masoumi, Hassan Hajghassem, Alireza Erfanian and Ahmad Molaei Rad
Smart sensors based on graphene field effect transistor (GFET) and biological receptors are regarded as a promising nanomaterial that could be the basis for future generation of…
Abstract
Purpose
Smart sensors based on graphene field effect transistor (GFET) and biological receptors are regarded as a promising nanomaterial that could be the basis for future generation of low-power, faster, selective real-time monitoring of target analytes and smaller electronics. So, the purpose of this paper is to provide details of sensors based on selective nanocoatings by combining trinitrotoluene (TNT) receptors (Trp-His-Trp) bound to conjugated polydiacetylene polymers on a graphene channel in GFET for detecting explosives TNT.
Design/methodology/approach
Following an introduction, this paper describes the way of manufacturing of the GFET sensor by using investigation methods for transferring graphene sheet from Cu foil to target substrates, which is functionalized by the TNT peptide receptors, to offer a system which has the capability of answering the presence of related target molecules (TNT). Finally, brief conclusions are drawn.
Findings
In a word, shortly after graphene discovery, it has been explored with a variety of methods gradually. Because of its exceptional electrical properties (e.g. extremely high carrier mobility and capacity), electrochemical properties such as high electron transfer rate and structural properties, graphene has already showed great potential and success in chemical and biological sensing fields. Therefore, the authors used a biological receptor with a field effect transistor (FET) based on graphene to fabricate sensor for achieving high sensitivity and selectivity that can detect explosive substances such as TNT. The transport property changed compared to that of the FET made by intrinsic graphene, that is, the Dirac point position moved from positive Vg to negative Vg, indicating the transition of graphene from p-type to n-type after annealing in TNT, and the results show the bipolar property change of GFET with the TNT concentration and the possibility to develop a robust, easy-to-use and low-cost TNT detection method for performing a sensitive, reliable and semi-quantitative detection in a wide detection range.
Originality/value
In this timeframe of history, TNT is a common explosive used in both military and industrial settings. Its convenient handling properties and explosive strength make it a common choice in military operations and bioterrorism. TNT and other conventional explosives are the mainstays of terrorist bombs and the anti-personnel mines that kill or injure more than 15,000 people annually in war-torn countries. In large, open-air environments, such as airports, train stations and minefields, concentrations of these explosives can be vanishingly small – a few parts of TNT, for instance, per trillion parts of air. That can make it impossible for conventional bomb and mine detectors to detect the explosives and save lives. So, in this paper, the authors report a potential solution with design and manufacture of a GFET sensor based on a biological receptor for real-time detection of TNT explosives specifically.
Details
Keywords
Can Saygin and Balaji Natarajan
The purpose of this paper is to investigate the impact of radio frequency identification (RFID) deployment at an airport baggage‐handling system (BHS).
Abstract
Purpose
The purpose of this paper is to investigate the impact of radio frequency identification (RFID) deployment at an airport baggage‐handling system (BHS).
Design/methodology/approach
The impact of number of RFID readers at different power levels with varying conveyor (i.e. baggage‐handling conveyors) speeds on timely delivery of baggage is studied via simulation. The layout of the BHS at the Hong Kong International Airport and data pertinent to its RFID deployment in 2005 are used to build the simulation model. The RFID read logic is based on the equations defined as a function of the number of tags and the time the tags spend in the interrogation zone for each reader in order to capture possible read‐rate issues realistically.
Findings
The identification capability of the BHS studied in this paper is a result of its combined ability to identify tags via RFID technology on straight and circulating conveyors, as well as at the manual recovery station for unidentified bags on circulating conveyors. Overall, timely delivery of bags to gates, as a performance metric, increases as the identification capability is improved. The controllable factors that affect the identification capability are the conveyor speed, which determines the time a tag stays in the interrogation zone; the reader antenna power level, which determines the size of the interrogation zone; and the number of reader antennas in the system that increases the likelihood of not missing tags. This paper shows that “the higher the number of reader antennas and the higher the power level on them, the better” approach is not correct.
Originality/value
Unlike typical simulation studies related to RFID deployment where read‐rate issues are considered to be non‐existent, this paper captures read rate in a realistic manner in the simulation model by incorporating the effect of number of RFID tags in the interrogation zone and time that RFID tags spend in the interrogation zone due to baggage conveyor speed. Such a simulation approach can be used as a system design tool in order to investigate the impact of RFID‐specific parameters on system‐level performance.
Details
Keywords
The purpose of this paper is to provide feasible and fast solutions for the multi-objective airport gate assignment problem (AGAP) considering both passenger-oriented and…
Abstract
Purpose
The purpose of this paper is to provide feasible and fast solutions for the multi-objective airport gate assignment problem (AGAP) considering both passenger-oriented and airline-oriented objectives, which is the total walking distance from gate to baggage carousels (TWD) and the total aircraft fuel consumption during taxi operations (TFC). In addition, obtaining feasible and near-optimal solutions in a short time reduces the gate planning time to be spent by air traffic controllers.
Design/methodology/approach
The mixed integer linear programming (MILP) approach is implemented to solve the multi-objective AGAP. The weighted sum approach technique was applied in the model to obtain non-dominated solutions. Because of the complexity of the problem, the simulated annealing (SA) algorithm was used for the proposed model. The results were compared with baseline results, which were obtained from the algorithm using the fastest gate assignment and baggage carousel combinations without any conflict taking place at the gate assignments.
Findings
The proposed model noticeably decreased both the TWD and TFC. The improvement of the TWD and TFC changed from 22.8% to 46.9% and from 4.7% to 7.1%, respectively, according to the priorities of the objectives. Additionally, the average number of non-dominated solutions was calculated as 6.94, which presents many feasible solutions for air traffic controllers to manage ground traffic while taking the airline and passenger objectives into consideration.
Practical implications
The proposed MILP model includes the objectives of different stakeholders: air traffic controllers, passengers and airlines. In addition, the proposed model can provide feasible gate and baggage carousel assignments together in a short time. Therefore, the model creates a flexibility for air traffic controllers to re-arrange assignments if any unexpected situations take place.
Originality/value
The proposed MILP model combines the TWD and TFC together for the AGAP problem using the SA. Moreover, the proposed model integrates passenger-oriented and airline-oriented objectives together and reveals the relationships between the objectives in only a short time.
Details
Keywords
Code-sharing, a phenomenon observed in international airline markets, has emerged as an important form of alliance in the domestic U.S. airline industry. Unlike international…
Abstract
Code-sharing, a phenomenon observed in international airline markets, has emerged as an important form of alliance in the domestic U.S. airline industry. Unlike international markets where code-share agreements were often the only way for a carrier to enter into a route serving another country, the post-1980 U.S. airline industry has enjoyed de facto free entry and exit. However, the financial conditions of the mid-1990s combined with various constraints on airport and airspace capacity led domestic carriers to experiment with code-sharing.