Dynamic Air Holding Program for Delay Assignment applied to Barcelona Airport Case

Nowadays, the aircraft is the most used transport to travel between two very distanced places since it is the fastest way. For these last years, the demand of flights has been increasing immensely, so the airports have been also suffering the same increase in workload. Congestion is the word for the imbalance between demand and capacity. After applying a Ground Holding Program (GHP) optimization process before departure to solve this problem in a previous work [1], in this project the Air Holding Program (AHP) is presented in order to minimize the economic costs once in the landing phase. The main goal of this final degree project is to implement a basic model of AHP to minimize the delay costs near the single destination airport, Barcelona-El Prat in this case. The model of AHP is based on a dynamic stochastic GHP. The problem is solved using Gurobi libraries. Firstly, a pre-tactical phase in [1] of GHP is applied to make flights wait on ground according to capacity constraints in the Barcelona Airport. Then, once the flights are already flying towards the destination and entering the analysed area (500 km from destination airport), these flights will perform a Free Route Airspace (FRA) route in order to make them fly a straight route trajectory to possibly shorten the flight duration, which will cause that the arrival queue be again disordered making the capacity constraint again violated. In order to minimize the air delay costs, a second optimization to assign air delay is applied called AHP. Once the flights are leaving this airspace, they will be communicated their final assigned holding. Finally when they are entering the landing phase, they should first pass through the holding procedure to hold the time needed according to the delay assigned. Some of the conclusions after this research is that if capacity is reduced in destination airport, firstly a GHP can be applied before departure [1]. Then, an AHP can be applied for a second optimization purpose. If traffic is directly taken to be applied an AHP, the capacity flexibility is very reduced, while using pre-tactical regulation the capacity could be as small as desired. This outlines the advantage of using GHP and AHP together. Furthermore, although the main objective is to minimize the delay costs, if the flights are arriving earlier than scheduled in the most optimal case, the delays could be negative values, which means that costs are saved

Dynamic Air Holding Program for Delay Assignment applied to Barcelona Airport Case

Nowadays, the aircraft is the most used transport to travel between two very distanced places since it is the fastest way. For these last years, the demand of flights has been increasing immensely, so the airports have been also suffering the same increase in workload. Congestion is the word for the imbalance between demand and capacity. After applying a Ground Holding Program (GHP) optimization process before departure to solve this problem in a previous work [1], in this project the Air Holding Program (AHP) is presented in order to minimize the economic costs once in the landing phase. The main goal of this final degree project is to implement a basic model of AHP to minimize the delay costs near the single destination airport, Barcelona-El Prat in this case. The model of AHP is based on a dynamic stochastic GHP. The problem is solved using Gurobi libraries. Firstly, a pre-tactical phase in [1] of GHP is applied to make flights wait on ground according to capacity constraints in the Barcelona Airport. Then, once the flights are already flying towards the destination and entering the analysed area (500 km from destination airport), these flights will perform a Free Route Airspace (FRA) route in order to make them fly a straight route trajectory to possibly shorten the flight duration, which will cause that the arrival queue be again disordered making the capacity constraint again violated. In order to minimize the air delay costs, a second optimization to assign air delay is applied called AHP. Once the flights are leaving this airspace, they will be communicated their final assigned holding. Finally when they are entering the landing phase, they should first pass through the holding procedure to hold the time needed according to the delay assigned. Some of the conclusions after this research is that if capacity is reduced in destination airport, firstly a GHP can be applied before departure [1]. Then, an AHP can be applied for a second optimization purpose. If traffic is directly taken to be applied an AHP, the capacity flexibility is very reduced, while using pre-tactical regulation the capacity could be as small as desired. This outlines the advantage of using GHP and AHP together. Furthermore, although the main objective is to minimize the delay costs, if the flights are arriving earlier than scheduled in the most optimal case, the delays could be negative values, which means that costs are saved

Assessment of Urban Vulnerability to Drought in Northern Slope of Tianshan Mountains

With the great change of global climate and urbanization, urban drought is becoming a more and more urgent problem that affects human beings. This research investigates specifically urban vulnerability towards drought in the arid regions, and claims that Urban Vulnerability to Drought (UVD) refers to the sensitivity and resilience towards urban droughts. Our evaluation of urban drought vulnerability intends to establish certain metrics of a particular urban system. The evaluation shall provide insights towards better management and sustainable development of the city in the long run. From a systematic point of view, we built a set of regional comprehensive vulnerability assessment indicator system. We adopt the entropy method and collect factors contributing to drought for cities on the northern slope of Tianshan Mountains in 2013. Data was from the city construction and social economic statistical yearbooks. Seven cities on the northern slope of Tianshan Mountains were selected to calculate a drought vulnerability metrics. Detailed analysis of the factors reveals critical factors that contribute to arid city\u27s drought vulnerability

Urban Vulnerability Analysis Based on Micro-Geographic Unit with Multi-Source Data—Case Study in Urumqi, Xinjiang, China

This study introduces a novel approach to urban public safety analysis inspired by a streetscape analysis commonly applied in urban criminology, leveraging the concept of micro-geographical units to account for urban spatial heterogeneity. Recognizing the intrinsic uniformity within these smaller, distinct environments of a city, the methodology represents a shift from large-scale regional studies to a more localized and precise exploration of urban vulnerability. The research objectives focus on three key aspects: first, establishing a framework for identifying and dividing cities into micro-geographical units; second, determining the type and nature of data that effectively illustrate the potential vulnerability of these units; and third, developing a robust and reliable evaluation index system for urban vulnerability. We apply this innovative method to Urumqi’s Tianshan District in Xinjiang, China, resulting in the formation of 30 distinct micro-geographical units. Using WorldView-2 remote sensing imagery and the object-oriented classification method, we extract and evaluate features related to vehicles, roads, buildings, and vegetation for each unit. This information feeds into the construction of a comprehensive index, used to assess public security vulnerability at a granular level. The findings from our study reveal a wide spectrum of vulnerability levels across the 30 units. Notably, units X1 (Er Dao Bridge) and X7 (Gold Coin Mountain International Plaza) showed high vulnerability due to factors such as a lack of green spaces, poor urban planning, dense building development, and traffic issues. Our research validates the utility and effectiveness of the micro-geographical unit concept in assessing urban vulnerability, thereby introducing a new paradigm in urban safety studies. This micro-geographical approach, combined with a multi-source data strategy involving high-resolution remote sensing and field survey data, offers a robust and comprehensive tool for urban vulnerability assessment. Moreover, the urban vulnerability evaluation index developed through this study provides a promising model for future urban safety research across different cities

Bayesian Network Modelling of ATC Complexity Metrics for Future SESAR Demand and Capacity Balance Solutions

Demand & Capacity Management solutions are key SESAR (Single European Sky ATM Research) research projects to adapt future airspace to the expected high air traffic growth in a Trajectory Based Operations (TBO) environment. These solutions rely on processes, methods and metrics regarding the complexity assessment of traffic flows. However, current complexity methodologies and metrics do not properly take into account the impact of trajectories’ uncertainty to the quality of complexity predictions of air traffic demand. This paper proposes the development of several Bayesian network (BN) models to identify the impacts of TBO uncertainties to the quality of the predictions of complexity of air traffic demand for two particular Demand Capacity Balance (DCB) solutions developed by SESAR 2020, i.e., Dynamic Airspace Configuration (DAC) and Flight Centric Air Traffic Control (FCA). In total, seven BN models are elicited covering each concept at different time horizons. The models allow evaluating the influence of the “complexity generators„ in the “complexity metrics„. Moreover, when the required level for the uncertainty of complexity is set, the networks allow identifying by how much uncertainty of the input variables should improve

Genetic diversity and population structure of indigenous chicken breeds in South China

A total of 587 individuals from 12 indigenous chicken breeds from South China and two commercial breeds were genotyped for 26 microsatellites to investigate the genetic diversity and population structure. All microsatellites were found to be polymorphic. The number of alleles per locus ranged from 5 to 36, with an average of 12.10 ± 7.00 (SE). All breeds, except White Recessive Rock, had high allelic polymorphism (>0.5). Higher genetic diversity was revealed in the indigenous chicken breeds rather than in the commercial breeds. Potential introgression from the commercial breeds into the indigenous chickens was also detected. The population structure of these indigenous chicken breeds could be explained by their geographical distribution, which suggested the presence of independent history of breed formation. Data generated in this study will provide valuable information to the conservation for indigenous chicken breeds in future

Increased Expression of TIGIT/CD57 in Peripheral Blood/Bone Marrow NK Cells in Patients with Chronic Myeloid Leukemia

The antitumor activity of NK cells in patients with chronic myeloid leukemia (CML) is inhibited by the leukemia microenvironment. Recent studies have identified that the expression of TIGIT, CD57, and KLRG1 is related to the function, maturation, and antitumor capabilities of NK cells. However, the characteristics of the expression of these genes in the peripheral blood (PB) and bone marrow (BM) from patients with CML remain unknown. In this study, we used multicolor flow cytometry to assay the quantity and phenotypic changes of NK cells in PB and BM from de novo CML (DN-CML) and CML patients acquiring molecular response (MR-CML). We found that the expression of TIGIT, which inhibits NK cell function, is increased on CD56+ and CD56dim NK cells in DN-CML PB compared with those in healthy individuals (HIs), and it is restored to normal in patients who achieve MR. We also found that the expression of CD57 on NK cells was approximately the same level in PB and BM from DN-CML patients, while decreased CD57 expression was found on CD56+ and CD56dim NK cells in HI BM compared with PB. Additionally, those two subsets were significantly increased in DN-CML BM compared to HI BM. The expression of CD57 correlates with replicative senescence and maturity for human NK cells; therefore, the increase in TIGIT on PB NK cells together with an increase in CD57 on BM NK cells may explain the subdued NK cell antileukemia capacity and proliferative ability in DN-CML patients. These results indicate that reversing the immune suppression of PB NK cells by blocking TIGIT while improving the proliferation of BM NK cells via targeting CD57 may be more effective in removing tumor cells

An Exposed Domain in the Severe Acute Respiratory Syndrome Coronavirus Spike Protein Induces Neutralizing Antibodies

Exposed epitopes of the spike protein may be recognized by neutralizing antibodies against severe acute respiratory syndrome (SARS) coronavirus (CoV). A protein fragment (S-II) containing predicted epitopes of the spike protein was expressed in Escherichia coli. The properly refolded protein fragment specifically bound to the surface of Vero cells. Monoclonal antibodies raised against this fragment recognized the native spike protein of SARS CoV in both monomeric and trimeric forms. These monoclonal antibodies were capable of blocking S-II attachment to Vero cells and exhibited in vitro antiviral activity. These neutralizing antibodies mapped to epitopes in two peptides, each comprising 20 amino acids. Thus, this region of the spike protein might be a target for generation of therapeutic neutralizing antibodies against SARS CoV and for vaccine development to elicit protective humoral immunity