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Collision risk assessment of reduced aircraft separation minima in procedural airspace using advanced communication and navigation

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Chinese Journal of Aeronautics 2023年第4期36卷 315-337页

作者： Qing CAI Hao Jie ANG sameer alam Air Traffic Management Research Institute School of Mechanical&Aerospace EngineeringNanyang Technological University639798Singapore

With the advancement of Communication,Navigation and Surveillance(CNS)technolo-gies such as space-based Automatic Dependent Surveillance-Broadcast/Contract(ADS-B/C),large separation minima may be reduced in procedural *** is of great significance to know the upper limit of the Reduced Separation Minima(RSM)for a procedural airspace and the corre-sponding consequences on collision risk with specifics of the advanced ADS-B and control interven-tion *** this work,an interactive software is first developed for collision risk *** software integrates the International Civil Aviation Organization(ICAO)collision risk models for lateral and longitudinal collision risk calculation for the Singapore procedural *** demonstrate that the lateral and longitudinal collision risk of Singapore procedural airspace with respect to current control procedures meets the ICAO Target Level of Safety(TLS)***,the feasibility of reducing the horizontal separations implemented in the Singapore pro-cedural airspace with respect to advanced CNS techniques is *** is found that if advanced CNS technologies are applied,then the current 50-NM lateral and longitudinal separa-tion standards can be reduced to 22 NM(1 NM=1.825 km)and 20 NM,respectively,to meet the TLS standards based on current demand.A method is then devised to expand the traffic demand by p for p∈[10%,200%].It is found that the minimum lateral and longitudinal separa-tions can be reduced from 50 NM to be within the range of[23,31]NM,and 20 NM,respectively,for p∈[10%,200%],while the collision risk still meets the TLS standards.

关键词： Air transportation Collision risk Procedural airspace Separation minima Space-based Automatic Dependent Surveillance-Bro adcast/Contract(ADS-B/C)

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An evolutionary computational framework for capacity-safety trade-off in an air transportation network

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Chinese Journal of Aeronautics 2019年第4期32卷 999-1010页

作者： Md.Murad HOSSAIN sameer alam Daniel DELAHAYE School of Engineering and Information Technology University of New South Wales School of Mechanical and Aerospace Engineering Nanyang Technological University MAIAA Laboratory Ecole Nationale de l'Aviation Civile

Airspace safety and airport capacity are two key challenges to sustain the growth in Air Transportation. In this paper, we model the Air Transportation Network as two sub-networks of airspace and airports, such that the safety and capacity of the overall Air Transportation network emerge from the interaction between the two. We propose a safety-capacity trade-off approach,using a computational framework, where the two networks can inter-act and the trade-off between capacity and safety in an Air Transport Network can be established. The framework comprise of an evolutionary computation based air traffic scenario generation using a flow capacity estimation module(for capacity), Collision risk estimation module(for safety) and an air traffic simulation module(for evaluation). The proposed methodology to evolve air traffic scenarios such that it minimizes collision risk for given capacity estimation was tested on two different air transport network topologies(random and small-world) with the same number of airports. Experimental results indicate that though airspace collision risk increases almost linearly with the increasing flow(flow intensity) in the corresponding airport network, the critical flow depend on the underlying network configuration. It was also found that, in general, the capacity upper bound depends not only on the connectivity among airports and their individual performances but also the configuration of waypoints and mid-air interactions among conflicts. Results also show that airport network can accommodate more traffic in terms of capacity but the corresponding airspace network cannot accommodate the resulting traffic flow due to the bounds on collision risk.

关键词： Airport network Airspace capacity Airspace safety Collision risk Flow intensity

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A Spatial-Temporal Network Perspective for the Propagation Dynamics of Air Traffic Delays

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Engineering 2021年第4期7卷 452-464页

作者： Qing Cai sameer alam Vu N.Duong School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore

Intractable delays occur in air traffic due to the imbalance between ever-increasing air traffic demand and limited airspace *** air traffic is associated with complex air transport systems,delays can be magnified and propagated throughout these systems,resulting in the emergent behavior known as delay *** understanding of delay propagation dynamics is pertinent to modern air traffic *** this work,we present a complex network perspective of delay propagation ***,we model air traffic scenarios using spatial–temporal networks with airports as the *** establish the dynamic edges between the nodes,we develop a delay propagation method and apply it to a given set of air traffic *** on the constructed spatial-temporal networks,we suggest three metrics-magnitude,severity,and speed-to gauge delay propagation *** validate the effectiveness of the proposed method,we carry out case studies on domestic flights in the Southeastern Asia region(SAR)and the United *** demonstrate that the propagation magnitude in terms of the number of flights affected by delay propagation and the amount of propagated delays for the US traffic are respectively five and ten times those of the *** further reveal that the propagation speed for US traffic is eight times faster than that of the *** delay propagation dynamics reveal that about six hub airports in the SAR have significant propagated delays,while the situation in the United States is considerably worse,with a corresponding number of around *** work provides a potent tool for tracing the evolution of air traffic delays.

关键词： Air traffic Transport systems Delay propagation dynamics Spatial–temporal networks

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AI-Driven Learning Management Systems:Modern Developments, Challenges and Future Trends during theAge of ChatGPT

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Computers, Materials & Continua 2024年第8期80卷 3289-3314页

作者： sameer Qazi Muhammad Bilal Kadri Muhammad Naveed Bilal AKhawaja Sohaib Zia Khan Muhammad Mansoor alam Mazliham Mohd Su’ud Department of Computer Science Faculty of EngineeringScience and TechnologyIQRA UniversityKarachi75500Pakistan College of Computer and Information Sciences Prince Sultan UniversityRiyadh11586Saudi Arabia Faculty of Engineering Department of Electrical EngineeringIslamic University of MadinahP.O.BOX 170Madinah41411Saudi Arabia Faculty of Engineering Department of Mechanical EngineeringIslamic University of MadinahP.O.BOX 170Madinah41411Saudi Arabia Faculty of Computing Riphah International UniversityIslamabad46000Pakistan Faculty of Computing and Informatics(FCI)Multimedia University Cyberjaya63100Malaysia Faculty of Engineering and Information Technology School of Computer ScienceUniversity of Technology SydneySydneyNSW 2007Australia

COVID-19 pandemic restrictions limited all social activities to curtail the spread of the *** foremost and most prime sector among those affected were schools,colleges,and *** education system of entire nations had shifted to online education during this *** shortcomings of Learning Management Systems(LMSs)were detected to support education in an online mode that spawned the research in Artificial Intelligence(AI)based tools that are being developed by the research community to improve the effectiveness of *** paper presents a detailed survey of the different enhancements to LMSs,which are led by key advances in the area of AI to enhance the real-time and non-real-time user *** AI-based enhancements proposed to the LMSs start from the Application layer and Presentation layer in the form of flipped classroom models for the efficient learning environment and appropriately designed UI/UX for efficient utilization of LMS utilities and resources,including AI-based *** layer enhancements are also required,such as AI-based online proctoring and user authentication using *** extend to the Transport layer to support real-time and rate adaptive encrypted video transmission for user security/privacy and satisfactory working of *** also needs the support of the Networking layer for IP-based geolocation features,the Virtual Private Network(VPN)feature,and the support of Software-Defined Networks(SDN)for optimum Quality of Service(QoS).Finally,in addition to these,non-real-time user experience is enhanced by other AI-based enhancements such as Plagiarism detection algorithms and Data Analytics.

关键词： Learning management systems chatbots ChatGPT online education Internet of Things(IoT) artificial intelligence(AI) convolutional neural networks natural language processing

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Unusual presentation of Erdheim-Chester disease in a child with acute lymphoblastic leukemia

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World Journal of Radiology 2016年第8期8卷 757-763页

作者： Archana George Vallonthaiel Asit Ranjan Mridha Shivanand Gamanagatti Manisha Jana Mehar Chand Sharma Shah alam Khan sameer Bakhshi Department of Pathology All India Institute of Medical Sciences Department of Radiodiagnosis All India Institute of Medical Sciences Department of Orthopaedics All India Institute of Medical Sciences Medical Oncology All India Institute of Medical Sciences

Erdheim-Chester disease(ECD) is an uncommon, nonfamilial, non-Langerhans cell histiocytosis, which involves skeletal system and soft tissue usually in middle aged and elderly patients. The characteristic radiologic features include bilateral, symmetric cortical osteosclerosis of the diaphyseal and metaphyseal parts of the long bones, or bilateral symmetrically abnormal intense 99 mTechnetium labelling of the metaphyseal-diaphyseal region of the long bones, and computed tomography scan findings of "coated aorta" or "hairy kidneys". ECD in childhood with osteolytic lesion is extremely rare. We describe an unusual case with an expansile lytic bone lesion at presentation in a case of acute lymphoblastic leukemia.

关键词： Erdheim-Chester disease Osteolytic lesion Bone Acute lymphoblastic leukemia

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