An airborne conflict resolution approach using a genetic algorithm

This paper presents a new flight trajectory optimisation method, based on genetic algorithms, where the selected optimisation criterion is the minimisation of the total cost. The candidate flight trajectories evaluated in the optimisation process are defined as flight plans with two components: a lateral flight plan (the set of geographic points that define the flight trajectory track segments) and a vertical flight plan (the set of data that define the altitude and speed profiles, as well as the points where the altitude and/or speed changes occur). The lateral components of the candidate flight plans are constructed by selecting a set of adjacent nodes from a routing grid. The routing grid nodes are generated based on the orthodromic route between the flight trajectory’s initial and final points, a selected maximum lateral deviation from the orthodromic route and a selected grid node step size along and across the orthodromic route. Two strategies are investigated to handle invalid flight plans (relative to the aircraft’s flight envelope) and to compute their flight performance parameters. A first strategy is to assign a large penalty total cost to invalid flight profiles. The second strategy is to adjust the invalid flight plan parameters (altitude and/or speed) to the nearest limit of the flight envelope, with priority being given to maintaining the planned altitude. The tests performed in this study show that the second strategy is computationally expensive (requiring more than twice the execution time relative to the first strategy) and yields less optimal solutions. The performance of the optimal profiles identified by the proposed optimisation method, using the two strategies regarding invalid flight profile performance evaluation, were compared with the performance data of a reference flight profile, using identical input data: initial aircraft weight, initial and final aircraft geographic positions, altitudes and speed, cost index, and atmospheric data. The initial and final aircraft geographic positions, and the reference flight profile data, were retrieved from the FlightAware web site. This data corresponds to a real flight performed with the aircraft model used in this study. Tests were performed for six Cost Index values. Given the randomness of the genetic algorithms, the convergence to a global optimal solution is not guaranteed (the solution may be non-optimal or a local optima). For a better evaluation of the performance of the proposed method, ten test runs were performed for each Cost Index value. The total cost reduction for the optimal flight plans obtained using the proposed method, relative to the reference flight plan, was between 0.822% and 3.042% for the cases when the invalid flight profiles were corrected, and between 1.598% and 3.97% for the cases where the invalid profiles were assigned a penalty total cost.

China has been gradually relaxing its ban on the use of low-altitude airspace across the country. To guarantee the high reliability of air traffic management (ATM), conflict detection and conflict resolution (CDR) approaches are indispensable to maintain safe separation between neighbouring small fixed-wing aircraft. In this study, we analyse a temporal and spatial integrated strategy for safety assessment purposes in opening the low-altitude urban airspace of Chinese pilot cities. First, we present a detailed mathematical description of the proposed algorithms based on a spatial grid partitioning system (SGPS). For our system, a conflict detection (CD) algorithm is designed to determine if two trajectories pass through the same grid space within overlapping time windows. A conflict resolution (CR) algorithm integrates a proposed time scheduling-based technique (TST) and vertical change-based technique (VCT), which operate under predetermined basic principles. Then, based on our novel CDR algorithms, a causal model is constructed in graphical modelling and analysis software (GMAS) to generate a state space that can provide a global perspective on scenario dynamics and better understanding of induced conflict occurrences. Finally, simulation results demonstrate that the proposed approach is practical and efficient.

NASA researchers, working under the Aviation System Capacity Program and in conjunction with the FAA Free Flight Program Office, have developed a set of decision support tools to assist terminal area air traffic controllers with control of arrival and departure traffic. Two of these tools, the Final Approach Spacing Tool (FAST) and the Expedite Departure Path (EDP) tool, provide air traffic controllers with heading, speed and altitude advisories to assist in spacing aircraft. This paper describes the conflict prediction and resolution algorithm shared by aFAST and EDP to produce conflict-free aircraft trajectories with realistic conflict resolution maneuvers. The process is accomplished in three stages: prediction, classification and resolution. A conflict prediction scheme is documented which incorporates all applicable FAA separation requirements, including automatic detection of separation during transition from staggered to simultaneous parallel approach operations. A method of classifying predicted conflicts with a limited set of criteria is detailed. Finally, a knowledge-based conflict resolution process is presented which allows for resolution of predicted conflicts in a manner consistent with controller practice: including prioritization of resolution tactics and mixture of multiple degrees of freedom to achieve separation. The scheme has been employed in both closed-loop simulations to determine solution stability and controller-in-the-loop simulations to begin development of the resolution tactics knowledge base.

Stochastic optimal control for aircraft conflict resolution under wind uncertainty

Conflict is inevitable to take place in collaborative design, and conflict resolution plays an important part in complex product collaborative design systems. Firstly, a mathematic description model in collaborative design considering resource conflict, process conflict and design conflict is given, and the mathematic model expresses the origin of conflict and shows that conflict resolution is a multiobjective planning problem. Next, a conflict resolution algorithm considering design objective optimization is presented, and fuzzy value and fuzzy grade are applied in the algorithm. Depending on both considering design variables having fundamental influences on its design objectives and the cost of conflict resolution, the algorithm can improve the quality and efficiency of conflict resolution. Finally, an example of single cylindrical gear reducer is used to show the validity of the algorithm.

A method for conflict detection and resolution based on the parameterization of the aircraft intents is presented. The method is also based on the use of predefined trajectory patterns, which are in fact flight intents; these patterns include standard airline procedures and air traffic control regulations. The conflict resolution problem is formulated as a parametric optimization problem subject to constraints; the optimality criterium is defined so that the deviation from the intended (preferred) trajectories in the lateral profile is minimized. The resolution trajectory patterns take into account changes of the nominal waypoints (vectoring) and changes of the aircraft speeds. The method is applied to the case of multiple conflicts among commercial transport aircraft in converging traffic in the terminal area; different scenarios are considered, which include locked aircraft, that is, aircraft whose trajectories are known and fixed. The conflict detection and resolution algorithm relies on a kinetic trajectory predictor (nonlinear point-mass model with variable mass), which is accurate, flexible, and transparent, and provides the high-fidelity prediction required in the analysis of the demanding terminal area traffic. The cost of the global conflict resolution process is assessed, in terms of extra distance traveled, extra flight time, and extra fuel consumed for each aircraft.

Conventional methods of flight planning for airborne LiDAR are heuristic in nature and use an iterative trial and error approach. A new system-based approach of flight planning is presented in this paper. The presented approach automatically derives flight planning parameters by minimizing the cost of data acquisition, which is represented by flight duration. The flight duration, which is the sum of the strip time and turning time, is minimized using genetic algorithms under the constraints of mapping requirements, hardware limitations, user-defined preferences, and various other requirements. The proposed approach is first validated for conventionally known test cases of regular shapes (rectangular and triangular). Thereafter, it is implemented for an arbitrarily shaped simulated test site with two commercially available airborne LiDAR sensors. Statistical results are presented for the above. Further, flight planning is performed for two real test sites. The demonstrated approach not only produces optimal results, but also avoids the assumptions of conventional methods. Furthermore, the approach requires the least amount of human intervention and, thus, eliminates the subjectivity that is imposed by individual flight planners for determining the flight planning parameters. Encouraged by these results, the authors suggest that the proposed approach can be further developed to include all possible components of flight planning in a future work.

- Efficient examination scheduling is critical for maintaining academic integrity and optimizing resources in educational institutions. This research focuses on developing an automated exam timetable generation system that dynamically resolves conflicts and accommodates diverse institutional constraints. By leveraging detailed algorithms for faculty invigilation, student schedules, room allocation, and conflict resolution, the system minimizes manual errors and improves operational efficiency. The proposed methodology includes real-time data collection, scheduling optimization, and robust invigilation assignment processes. Expected outcomes of this research include significant reductions in scheduling time, enhanced stakeholder satisfaction, and scalability to accommodate institutional growth. By addressing existing gaps in scheduling methods, this study offers a transformative approach to academic resource management, setting the foundation for advancements in educational technology. Key Words: Examination Scheduling, Timetable Generation, Conflict Resolution, Faculty Availability, Resource Optimization, Educational Technology, Automation, Scalability, Greedy approach, Sophisticated Algorithm

Unmanned Aircraft Systems (UAS) are rapidly gaining attention due to the increasing potential of their applications in the civil domain. UAS can provide great value performing environmental applications, during emergency situations, as monitoring and surveillance tools, and operating as communication relays among other uses. In general, they are specially well suited for the so-called D-cube operations (Dirty, Dull or Dangerous).<br/>Most current commercial solutions, if not remotely piloted, rely on waypoint based flight control systems for their navigation and are unable to coordinate UAS flight with payload operation. Therefore, automation capabilities and the ability for the system to operate in an autonomous manner are very limited. Some motivators that turn autonomy into an important requirement include limited bandwidth, limits on long-term attention spans of human operators, faster access to sensed data, which also results in better reaction times, as well as benefits derived from reducing operators workload and training requirements.<br/>Other important requirements we believe are key to the success of UAS in the civil domain are reconfigurability and cost-effectiveness. As a result, an affordable platform should be able to operate in different application scenarios with reduced human intervention.<br/>To increase capabilities of UAS and satisfy the aforementioned requirements, we propose adding flight plan and mission management layers on top of a commercial off-the-shelf flight control system. By doing so, a high level of autonomy can be achieved while taking advantage of available technologies and avoiding huge investments. Reconfiguration is made possible by separating flight and mission execution from its specification.<br/>The flight and mission management components presented in this thesis integrate into a wider hardware/software architecture being developed by the ICARUS research group.<br/>This architecture follows a service oriented approach where UAS subsystems are connected together through a common networking infrastructure. Components can be added and removed from the network in order to adapt the system to the target mission.<br/>The first contribution of this thesis consists, then, in a flight specification language that enables the description of the flight plan in terms of legs. Legs provide a higher level of abstraction compared to plain waypoints since they not only specify a destination but also the trajectory that should be followed to reach it. This leg concept is extended with additional constructs that enable specification of alternative routes, repetition and generation of complex trajectories from a reduced number of parameters.<br/>A Flight Plan Manager (FPM) service has been developed that is responsible for the execution of the flight plan. Since the underlying flight control system is still waypoint based, additional intermediate waypoints are automatically generated to adjust the flight to the desired trajectory.<br/>In order to coordinate UAS flight and payload operation a Mission Manager (MMa) service has also been developed. The MMa is able to adapt payload operation according to the current flight phase, but it can also act on the FPM and make modifications on the flight plan for a better adaption to the mission needs. To specify UAS behavior, instead of designing a new language, we propose using an in-development standard for the specification of state machines called State Chart XML.<br/>Finally, validation of the proposed specification and execution elements is carried out with two example missions executed in a simulation environment. The first mission mimics the procedures required for inspecting navigation aids and shows the UAS performance in a complex flight scenario. In this mission only the FPM is involved. The second example combines operation of the FPM with the MMa. In this case the mission consists in the detection of hotspots on a given area after a hypothetical wildfire. This second simulation shows how the MMa is able to modify the flight plan in order to adapt the trajectory to the mission needs. In particular, an eight pattern is flown over each of the dynamically detected potential hot spots.

This study aims to evaluate the effectiveness of the United Nations Security Council's resolutions on Cyprus within the framework of the conflict resolution approach. Due to the conflict resolution approach, the position of Turkey, which is on the other side of the conflict and is the guarantor state, is also included in the evaluation with some suggestions. In this context, 152 Security Council resolutions between 1960 and 2021 have been examined. The results show that the Security Council has not been analyzed Cyprus' recent history well. Even the proposal to return to the 1960 Nicosia Treaty is a concrete indicator of this fact. In this sense, the Security Council has not been successful in terms of conflict resolution on Cyprus issue. On the other hand, Turkey, condemned within the framework of the Security Council resolutions, has not been able to explain itself well to the international community regarding Cyprus. The conflict resolution approach at least points that Turkey and Turkish Cypriots have also arguments to put forward for a satisfying solution.

Next generation air transportation system (NextGen) concepts of operation may require aircraft to fly planned trajectories in four dimensions - three spatial dimensions and time. A prototype 4D flight management capability is being developed by NASA to facilitate the development of these concepts. New trajectory generation functions extend todaypsilas flight management system (FMS) capabilities that meet a single required time of arrival (RTA) to trajectory solutions that comply with multiple RTA constraints. When a solution is not possible, a constraint management capability relaxes constraints to achieve a trajectory solution that meets the most important constraints as specified by candidate NextGen concepts. New flight guidance functions provide continuous guidance to the aircraftpsilas flight control system to enable it to fly specified 4D trajectories. Guidance options developed for research investigations include a moving time window with varying tolerances that are a function of proximity to imposed constraints, and guidance that recalculates the aircraftpsilas planned trajectory as a function of the estimation of current compliance. Compliance tolerances are related to required navigation performance (RNP) through the extension of existing RNP concepts for lateral containment. A conceptual temporal RNP implementation and prototype display symbology are proposed.

Constrained resource sharing and conflict resolution in Hebe

This study analyzed the impact of emotional intelligence on the conflict resolution effectiveness of HR practitioners in the major cities of Pakistan. The research also focused on the value of the various elements of emotional intelligence on the conflict resolution approach taken and the results achieved. Within the study, 150 HR practitioners completed emotional intelligence and conflict resolution effectiveness questionnaires, in addition to 20 senior professionals who were involved in semi-structured interviews. The five cities of Pakistan, i.e. Karachi, Lahore, Islamabad, Peshawar, and Quetta, were the target sample cities of this research study. This research study lasted from January to April 2025. The results of the quantitative study showed the presence of positive correlations in the emotional intelligence elements of self-awareness, self-regulation, empathy, social skills, and conflict resolution effectiveness, with the strongest and most significant resolution effectiveness correlation being empathy (r=0.782, p<0.001). The results of the qualitative findings showed the five self-regulated and emotionally intelligent HR professionals active, implemented and utilized the strategies of listening, emotional regulation, perspective-taking, collaborative problem-solving, relationship maintenance, and these strategies were linked with and formed successful outcomes in conflict resolution. Based on these findings, this research study showed that in the Pakistani context, emotional intelligence positively impacts the workplace conflict resolution skills of HR professionals and is thus, an important skill that they should possess to maintain workplace harmony.

The pilot- and controller-in-the-loop simulation described in this paper demonstrates the potential benefits of a near-term trajectory-based operations concept with datalink communications. Near-term operations with datalink are characterized by a fleet of which not all aircraft are equipped with datalink communications (i.e., mixed equipage). The objectives of this simulation were to continue to develop capabilities such as the conflict resolution algorithm, as well as evaluate new capabilities and concepts such as tactical conflict detection and trajectory-based weather avoidance with feedback from experienced pilots and controllers. Conflict resolutions and tactical conflict detections were compared to controller actions. The direction of the conflict resolution maneuver advised by the algorithm agreed with controller actions 79% of the time when both chose to apply the same type of resolution maneuver to the same aircraft. Comparing controller actions to conflicts detected by the tactical conflict detection function revealed no missed alerts and a false alert rate of 11%. Trajectory-based weather avoidance functions received high ratings from the controllers for usefulness and ease of use. In particular, controllers noted weather avoidance reroutes originating from a simulated traffic management coordinator position alleviated their concerns about potentially disrupting traffic flow management plans, thus expediting the issuance of the reroutes.

This paper discusses the application of the prototyping approach to investigating the requirements on strategies for cooperative planning and conflict resolution of independent agents by means of an example application: the strategic game “Scotland Yard”. The strategies for coordinating the agents, which are parallel algorithms, are developed with a prototyping approach using ProSet-Linda. ProSet-Linda is designed for prototyping parallel algorithms.We concentrate on the techniques employed to elicit the requirements on the algorithms for agent interaction. The example application serves to illustrate the prototyping approach to requirements elicitation by means of a non-trivial instance for investigating algorithms for cooperative planning and conflict resolution.