Decentralized Conflict Resolution Research Articles

РАЗРАБОТКА МЕТОДИКИ ИДЕНТИФИКАЦИИ И РАЗРЕШЕНИЯ КОНФЛИКТНЫХ СИТУАЦИЙ ПРИ ОПЕРАТИВНОМ ПЛАНИРОВАНИИ ЧЕТЫРЕХМЕРНОЙ ТРАЕКТОРИИ ПОЛЕТА

Conflict detection and resolution is one of the key tasks in ensuring the safety and efficiency of air transport. In Trajectory Based Operation (TBO), aircraft are given greater flexibility in planning trajectories along the route and greater responsibility for self-separation from each other, so the pilot will need assistance to safely and efficiently perform the task of decentralized conflict resolution during the en-route flight. In this work, we develop a method for identifying and resolving conflict situations in cruising phase based on four-dimensional grid nodes (4D-grid) and the A-star shortest path search algorithm (A* for short) to form an optimal four-dimensional trajectory (4D-trajectory) bypass all airspace obstacles. This new approach helps to avoid false warnings about potential conflicts due to the ability to early detect them and accurately determine the distance from aircraft to areas of dangerous proximity (prohibited zones (PZ), zones of bad weather, other aircraft) and then autonomously form a time-spatial trajectory to bypass them. In order to demonstrate the effectiveness of the proposed method, we conduct three experiments in different airspace conditions (with and without the areas of dangerous proximity). The results of the experiments prove that potential dangerous proximities of aircraft in flight are effectively identified and resolved using the proposed methodology.

DeResolver: A Decentralized Conflict Resolution Framework with Autonomous Negotiation for Smart City Services

As various smart services are increasingly deployed in modern cities, many unexpected conflicts arise due to various physical world couplings. Existing solutions for conflict resolution often rely on centralized control to enforce predetermined and fixed priorities of different services, which is challenging due to the inconsistent and private objectives of the services. Also, the centralized solutions miss opportunities to more effectively resolve conflicts according to their spatiotemporal locality of the conflicts. To address this issue, we design a decentralized negotiation and conflict resolution framework named DeResolver, which allows services to resolve conflicts by communicating and negotiating with each other to reach a Pareto-optimal agreement autonomously and efficiently. Our design features a two-step self-supervised learning-based algorithm to predict acceptable proposals and their rankings of each opponent through the negotiation. Our design is evaluated with a smart city case study of three services: intelligent traffic light control, pedestrian service, and environmental control. In this case study, a data-driven evaluation is conducted using a large dataset consisting of the GPS locations of 246 surveillance cameras and an automatic traffic monitoring system with more than 3 million records per day to extract real-world vehicle routes. The evaluation results show that our solution achieves much more balanced results, i.e., only increasing the average waiting time of vehicles, the measurement metric of intelligent traffic light control service, by 6.8% while reducing the weighted sum of air pollutant emission, measured for environment control service, by 12.1%, and the pedestrian waiting time, the measurement metric of pedestrian service, by 33.1%, compared to priority-based solution.

Emergence of 4-D System Fundamental Diagram in Urban Air Mobility Traffic Flow

Urban air mobility (UAM) is an emerging mode that promises to provide relief to congested urban streets. UAM relies on airspace, however, which is an exhaustible resource considering minimum aircraft separation requirements. In light of these requirements and UAM vehicle attributes, a simulation is developed to explore UAM traffic flows and congestion development. A decentralized conflict resolution scheme is employed in the form of a non-linear program (NLP) to offer improved flexibility in detours relative to past aircraft simulations. An expansion of Edie’s definitions of density and flow rate are used in conjunction with average speed to explore the relationships between traffic flow characteristics. The results find that UAM traffic flows emulate those of other modes, by following the familiar traffic patterns of build-up and breakdown captured in the macroscopic fundamental diagram. These findings also suggest the presence of a capacity of airspace that should be carefully managed by operators to achieve optimal system performance. The relationships established in this study highlight issues that UAM operators and aviation planners may face and could be used to improve the vehicle traffic modeling of other UAM models.

Property Rights and Institutional Arrangements of a Man-Made Wetland in Dryland Area of West Bengal, India

The property right is one of the most vital factors determining the sustainable governance and utilization of the wetlands. The paper analyses property right issues and institutional arrangements of a rural man-made wetland in dryland areas of West Bengal, India. It uses Participatory Rural Appraisal, Key-Informant’s Interview, Focus Group Discussion, and household interview to accomplish this objective. The wetland, being located in the dryland landscape, serves as the primary freshwater source for surrounding communities and is used for multiple purposes. However, the conflict among the stakeholders on property right has caused the dissolution of the traditional local institution. Lack of regulation on water and fish extraction from the wetland affected essential human activities like household use, irrigation, and fishery. Moreover, conflict among the stakeholders adversely eroded any form of collective action for maintenance and renovation of the wetland. The study suggests that decentralized conflict resolution through dialogue is the pre-requisite for encouraging collective action and development of institutional arrangements which are vital for the restoration and sustainable utilization of the wetland.

X-gtrbac admin

The modern enterprise spans several functional units or administrative domains with diverse authorization requirements. Access control policies in an enterprise environment typically express these requirements as authorization constraints. While desirable for access control, constraints can lead to conflicts in the overall policy in a multidomain environment. The administration problem for enterprise-wide access control, therefore, not only includes authorization management for users and resources within a single domain but also conflict resolution among heterogeneous access control policies of multiple domains to allow secure interoperation within the enterprise. This work presents design and implementation of X-GTRBAC Admin, an administration model that aims at enabling administration of role-based access control (RBAC) policies in the presence of constraints with support for conflict resolution in a multidomain environment. A key feature of the model is that it allows decentralization of policy administration tasks through the abstraction of administrative domains, which not only simplifies authorization management, but is also fundamental to the concept of decentralized conflict resolution presented. The paper also illustrates the applicability of the outlined administrative concepts in a realistic enterprise environment using an implementation prototype that facilitates policy administration in large enterprises.

Stability and performance of intersecting aircraft flows under decentralized conflict avoidance rules

This paper considers the problem of two intersecting aircraft flows under decentralized conflict resolution rules. Considering aircraft flowing through a fixed control volume, new air traffic control models and scenarios are defined that enable the study of long-term aircraft flow stability. For a class of two intersecting aircraft flows, this paper considers conflict scenarios involving arbitrary encounter angles. It is shown that aircraft flow stability, defined both in terms of safety and performance, is preserved under the decentralized conflict resolution algorithm considered. It is shown that the lateral deviations experienced by aircraft in each flow are bounded.