Architecture and Information Requirements to Assess and Predict Flight Safety Risks During Highly Autonomous Urban Flight Operations

As aviation adopts new and increasingly complex operational paradigms, vehicle types, and technologies to broaden airspace capability and efficiency, maintaining a safe system will require recognition and timely mitigation of new safety issues as they emerge and before significant consequences occur. A shift toward a more predictive risk mitigation capability becomes critical to meet this challenge. In-time safety assurance comprises monitoring, assessment, and mitigation functions that proactively reduce risk in complex operational environments where the interplay of hazards may not be known (and therefore not accounted for) during design. These functions can also help to understand and predict emergent effects caused by the increased use of automation or autonomous functions that may exhibit unexpected non-deterministic behaviors. The envisioned monitoring and assessment functions can look for precursors, anomalies, and trends (PATs) by applying model-based and data-driven methods. Outputs would then drive downstream mitigation(s) if needed to reduce risk. These mitigations may be accomplished using traditional design revision processes or via operational (and sometimes automated) mechanisms. The latter refers to the in-time aspect of the system concept. This report comprises architecture and information requirements and considerations toward enabling such a capability within the domain of low altitude highly autonomous urban flight operations. This domain may span, for example, public-use surveillance missions flown by small unmanned aircraft (e.g., infrastructure inspection, facility management, emergency response, law enforcement, and/or security) to transportation missions flown by larger aircraft that may carry passengers or deliver products. Caveat: Any stated requirements in this report should be considered initial requirements that are intended to drive research and development (R&D). These initial requirements are likely to evolve based on R&D findings, refinement of operational concepts, industry advances, and new industry or regulatory policies or standards related to safety assurance

Efficient Database Generation for Data-driven Security Assessment of Power Systems

Power system security assessment methods require large datasets of operating points to train or test their performance. As historical data often contain limited number of abnormal situations, simulation data are necessary to accurately determine the security boundary. Generating such a database is an extremely demanding task, which becomes intractable even for small system sizes. This paper proposes a modular and highly scalable algorithm for computationally efficient database generation. Using convex relaxation techniques and complex network theory, we discard large infeasible regions and drastically reduce the search space. We explore the remaining space by a highly parallelizable algorithm and substantially decrease computation time. Our method accommodates numerous definitions of power system security. Here we focus on the combination of N-k security and small-signal stability. Demonstrating our algorithm on IEEE 14-bus and NESTA 162-bus systems, we show how it outperforms existing approaches requiring less than 10% of the time other methods require.Comment: Database publicly available at: https://github.com/johnnyDEDK/OPs_Nesta162Bus - Paper accepted for publication at IEEE Transactions on Power System

Assessing UAM emergency procedures in existing or new heliports

With the rising interest from big investors and manufacturers in UAM solutions, many vehicle prototypes and ground infrastructure designs are beginning to appear and being tested in real-world scenarios. This mode of air transportation could be a game-changer if the different milestones are achieved. While there are many challenges to be covered, from noise pollution to airspace management, safety is probably one of the main elements to be assessed. And while much effort has been given into designing and promoting UAM vehicles, little research has been published or conducted about safety considerations. This study provides with a discussion on different findings related to safety based on a root cause analysis of reported and documented helicopter accidents involving similar environments and conditions to those UAM will face. By assessing these hazards in similar VTOL aircraft such as helicopters, an extrapolation to UAM vehicles is made for different types of vehicles, depending on their characteristics and performance capabilities observed in various prototypes. The analysis is divided in two main parts. The first part focuses on the different occurrences involved in the accidents, following the CICTT standard definitions for reporting aviation accidents and incidents. The second part goes deeper and analyses the causes involved that lead to those occurrences, and how these could apply to UAM vehicles. The discussion considers the identified hazards in different levels, depending on factors such as human presence and automation, and their impact on criticality, prevention and mitigation. The overall study provides with some guidelines on safety issues that are considered relevant for future research in the field of UAM, as well as for the future standardization of the necessary elements to implement and regulate these systems in urban centers

Opportunities for improving environmental compliance in Mexico

Survey evidence from Mexico reveals large observed differences in pollution from factories in the same industry, or the same area, or operating under the same regulatory regime. Many factories have adopted significant measures for pollution control and are in compliance with environmental regulations, but some have made little or no such effort. For lack of data, systematic research on the reasons behind such variations in plant-level environmental performance (especially on how impediments to pollution control affect plant behavior) is rare, even in industrial societies. Drawing on a recent plant-level survey of Mexican factories, the author identifies a number of performance variables characteristic of compliant and non-compliant plants, as well as factors that no-compliant plants perceive to be obstacles to pollution control. Non-compliant firms made less effort than compliant firms to change materials, used, to change production processes, or to install end-of-pipe treatment equipment. They had significantly fewer programs to train their general workers in environmental responsibilities. They lagged behind in environmental training, waste management, and transportation training. They received less technical training, especially about the environment, environmental policy and administration, and clean technology and audits. Responses about obstacles to better environmental performance included scarcity of training resources, government bureaucracy, high interest rates, and Mexico's lack of an environmental protection culture. Respondents said that senior managers did not emphasize the environment, assigned more priority to economic considerations, and were not trained in the subject. Most important, however, little information was available about Mexico's environmental policy. These findings suggest the importance of technical assistance - especially training and information. In Mexico, the information gap on policy is a major problem. Mexican environmental agencies should invest more in technical assistance and environmental training targeted to non-compliant enterprises. Environmental education, especially of senior managers, could significantly improve pollution control. Maintaining close contact with non-compliant firms, designing programs targeted to them, and pursuing them systemically should increase their responsiveness to regulations.ICT Policy and Strategies,Environmental Economics&Policies,Public Health Promotion,Water and Industry,Health Monitoring&Evaluation,Environmental Economics&Policies,Water and Industry,Health Monitoring&Evaluation,ICT Policy and Strategies,Agricultural Research

How explicit are the barriers to failure in safety arguments?

Safety cases embody arguments that demonstrate how safety properties of a system are upheld. Such cases implicitly document the barriers that must exist between hazards and vulnerable components of a system. For safety certification, it is the analysis of these barriers that provide confidence in the safety of the system. The explicit representation of hazard barriers can provide additional insight for the design and evaluation of system safety. They can be identified in a hazard analysis to allow analysts to reflect on particular design choices. Barrier existence in a live system can be mapped to abstract barrier representations to provide both verification of barrier existence and a basis for quantitative measures between the predicted barrier behaviour and performance of the actual barrier. This paper explores the first stage of this process, the binding between explicit mitigation arguments in hazard analysis and the barrier concept. Examples from the domains of computer-assisted detection in mammography and free route airspace feasibility are examined and the implications for system certification are considered

On standards and values: Between finite actuality and infinite possibility

This article explores the relation between subjects and standards in a way that is informed by a process orientation to theoretical psychology. Standards are presented as objectifications of values designed to generalize and stabilize experiences of value. Standards are nevertheless prone to becoming “parodic” in the sense that they can become obstacles to the actualization of the values they were designed to incarnate. Furthermore, much critical social science has mishandled the nature of standards by insisting that values are nothing but local and specific constructions in the mundane world of human activity. To rectify this problem, this article reactivates a sense of the difference between the idea of a finite world of activity and a world of value which points beyond and exceeds passing circumstance. Resources for the reactivation of this difference— which is core to a processual grasp of self, memory, and value—are found in the thinking of A. N. Whitehead, Max Weber, Marcel Proust, and Soren Kierkegaard

Letting Go of “Natural Kind”: Toward a Multidimensional Framework of Nonarbitrary Classification

This article uses the case study of ethnobiological classification to develop a positive and a negative thesis about the state of natural kind debates. On the one hand, I argue that current accounts of natural kinds can be integrated in a multidimensional framework that advances understanding of classificatory practices in ethnobiology. On the other hand, I argue that such a multidimensional framework does not leave any substantial work for the notion “natural kind” and that attempts to formulate a general account of naturalness have become an obstacle to understanding classificatory practices