On the Fock Transformation in Nonlinear Relativity

In this paper, we propose a new deformed Poisson brackets which leads to the Fock coordinate transformation by using an analogous procedure as in Deformed Special Relativity. We therefore derive the corresponding momentum transformation which is revealed to be different from previous results. Contrary to the earlier version of Fock's nonlinear relativity for which plane waves cannot be described, our resulting algebra keeps invariant for any coordinate and momentum transformations the four dimensional contraction $p_{\mu} x^{\mu}$, allowing therefore to associate plane waves for free particles. As in Deformed Special Relativity, we also derive a canonical transformation with which the new coordinates and momentum satisfy the usual Poisson brackets and therefore transform like the usual Lorentz vectors. Finally, we establish the dispersion relation for Fock's nonlinear relativity.Comment: 10 pages, no figure

Health and incomes in Malawi and the KwaZulu-Natal province of South Africa

This thesis examines the relationship between health and income in Malawi and the KwaZulu-Natal province in South Africa. The first empirical chapter considers the previously unused Second Integrated Household Survey (IHS2) to examine child mortality in Malawi. Household income and bed net use are included within the analysis presented in addition to the standard proximate determinants of population health. It is found that possessing at least some education and using bed nets significantly reduces child deaths. The second empirical chapter explores the effect of morbidity upon daily wage rates in Malawi using the IHS2. The results suggest that even relatively short periods of morbidity reduce the daily wage received by relatively large amounts. The final empirical chapter examines the impact of different types of “health shocks” upon household income in 1998 and 2004 using the KwaZulu-Natal Income Dynamics Study (KIDS) dataset. The results suggest that the effect of “health shocks” upon household income is negative in 1998 using a propensity score matching method. Direct income losses associated with shocks are also examined and indicate that for most households the effect of health shocks is generally small.ESR

Adaptive Integral High‐Order Sliding Mode for a Fixed Wing Aircraft

In order to develop and implement the laws piloting for an aircraft, flights validation will be necessary. This could in fact be done, in a first step, by using flight simulators. In this work, we choose the predator virtual model flying in MicrosoftTM flight simulator (MSFS) and we propose the procedure of controlling its attitude. We send the adaptive integral high‐order sliding mode (AIHOSM) inputs piloting control. This work is a real‐time virtual simulation. For the AIHOSM controller, we propose the gain adaptation for reduction of chattering phenomena and possibility to control the aircraft presented by the uncertain nonlinear systems in which the uncertainties have unknown bounds. This technique is more robust and simpler to implement than the quaternion one and only needs the information about the sliding mode surface

Scalable Computation of Inter-Core Bounds Through Exact Abstractions

Real-time systems (RTSs) are at the heart of numerous safety-critical applications. An RTS typically consists of a set of real-time tasks (the software) that execute on a multicore shared-memory platform (the hardware) following a scheduling policy. In an RTS, computing inter-core bounds, i.e., bounds separating events produced by tasks on different cores, is crucial. While efficient techniques to over-approximate such bounds exist, little has been proposed to compute their exact values. Given an RTS with a set of cores C and a set of tasks T , under partitioned fixed-priority scheduling with limited preemption, a recent work by Foughali, Hladik and Zuepke (FHZ) models tasks with affinity c (i.e., allocated to core c in C) as a Uppaal timed automata (TA) network Nc. For each core c in C, Nc integrates blocking (due to data sharing) using tight analytical formulae. Through compositional model checking, FHZ achieved a substantial gain in scalability for bounds local to a core. However, computing inter-core bounds for some events of interest E, produced by a subset of tasks TE with different affinities CE, requires model checking the parallel composition of all TA networks Nc for each c in CE, which produces a large, often intractable, state space. In this paper, we present a new scalable approach based on exact abstractions to compute exact inter-core bounds in a schedulable RTS, under the assumption that tasks in TE have distinct affinities. We develop a novel algorithm, leveraging a new query that we implement in Uppaal, that computes for each TA network Nc in NE an abstraction A(Nc) preserving the exact intervals within which events occur on c, therefore drastically reducing the state space. The scalability of our approach is demonstrated on the WATERS 2017 industrial challenge, for which we efficiently compute various types of inter-core bounds where FHZ fails to scale.Comment: To appear in the proceedings of the 48th IEEE International Conference on Computers, Software, and Applications (COMPSAC 2024

Scalable Computation of Inter-Core Bounds Through Exact Abstractions

Real-time systems (RTSs) are at the heart of numerous safety-critical applications. An RTS typically consists of a set of real-time tasks (the software) that execute on a multicore shared-memory platform (the hardware) following a scheduling policy. In an RTS, computing inter-core bounds, i.e., bounds separating events produced by tasks on different cores, is crucial. While efficient techniques to over-approximate such bounds exist, little has been proposed to compute their exact values. Given an RTS with a set of cores C and a set of tasks T , under partitioned fixed-priority scheduling with limited preemption, a recent work by Foughali, Hladik and Zuepke (FHZ) models tasks with affinity c (i.e., allocated to core c in C) as a Uppaal timed automata (TA) network Nc. For each core c in C, Nc integrates blocking (due to data sharing) using tight analytical formulae. Through compositional model checking, FHZ achieved a substantial gain in scalability for bounds local to a core. However, computing inter-core bounds for some events of interest E, produced by a subset of tasks TE with different affinities CE, requires model checking the parallel composition of all TA networks Nc for each c in CE, which produces a large, often intractable, state space. In this paper, we present a new scalable approach based on exact abstractions to compute exact inter-core bounds in a schedulable RTS, under the assumption that tasks in TE have distinct affinities. We develop a novel algorithm, leveraging a new query that we implement in Uppaal, that computes for each TA network Nc in NE an abstraction A(Nc) preserving the exact intervals within which events occur on c, therefore drastically reducing the state space. The scalability of our approach is demonstrated on the WATERS 2017 industrial challenge, for which we efficiently compute various types of inter-core bounds where FHZ fails to scale

A Theory of (Linear-Time) Timed Monitors (Artifact)

We provide an OCaml implementation of the logics MTL and T^lin, as well as monitors. Our artefact includes a compiler that translates T^lin formulae into monitors. The generation of a monitor M from some formula ϕ is decorated with a warning whenever ϕ is not in the syntax of the maximally-expressive monitorable fragment. The resulting monitors being reactive and deterministic, we also implement their semantics, and provide further a pseudo-monitoring prototype where the monitor incrementally consumes an infinite timed word and reaches a verdict whenever possible. For convenience, for users that prefer to use MTL (bearing in mind the loss of expressivity), we also provide a compiler from MTL to T^lin