An Agent-Oriented Hierarchic Strategy for Solving Inverse Problems

The paper discusses the complex, agent-oriented hierarchic memetic strategy (HMS) dedicated to solving inverse parametric problems. The strategy goes beyond the idea of two-phase global optimization algorithms. The global search performed by a tree of dependent demes is dynamically alternated with local, steepest descent searches. The strategy offers exceptionally low computational costs, mainly because the direct solver accuracy (performed by the hp-adaptive finite element method) is dynamically adjusted for each inverse search step. The computational cost is further decreased by the strategy employed for solution inter-processing and fitness deterioration. The HMS efficiency is compared with the results of a standard evolutionary technique, as well as with the multi-start strategy on benchmarks that exhibit typical inverse problems' difficulties. Finally, an HMS application to a real-life engineering problem leading to the identification of oil deposits by inverting magnetotelluric measurements is presented. The HMS applicability to the inversion of magnetotelluric data is also mathematically verified

A multi-objective memetic inverse solver reinforced by local optimization methods

We propose a new memetic strategy that can solve the multi-physics, complex inverse problems, formulated as the multi-objective optimization ones, in which objectives are misfits between the measured and simulated states of various governing processes. The multi-deme structure of the strategy allows for both, intensive, relatively cheap exploration with a moderate accuracy and more accurate search many regions of Pareto set in parallel. The special type of selection operator prefers the coherent alternative solutions, eliminating artifacts appearing in the particular processes. The additional accuracy increment is obtained by the parallel convex searches applied to the local scalarizations of the misfit vector. The strategy is dedicated for solving ill-conditioned problems, for which inverting the single physical process can lead to the ambiguous results. The skill of the selection in artifact elimination is shown on the benchmark problem, while the whole strategy was applied for identification of oil deposits, where the misfits are related to various frequencies of the magnetic and electric waves of the magnetotelluric measurement

Multi-objective hierarchic memetic solver for inverse parametric problems

We propose a multi-objective approach for solving challenging inverse parametric problems. The objectives are misfits for several physical descriptions of a phenomenon under consideration, whereas their domain is a common set of admissible parameters. The resulting Pareto set, or parameters close to it, constitute various alternatives of minimizing individual misfits. A special type of selection applied to the memetic solution of the multi-objective problem narrows the set of alternatives to the ones that are sufficiently coherent. The proposed strategy is exemplified by solving a real-world engineering problem consisting of the magnetotelluric measurement inversion that leads to identification of oil deposits located about 3 km under the Earth's surface, where two misfit functions are related to distinct frequencies of the electric and magnetic waves

Managing tourism decline: insights from the Isle of Man

Qualitative interviews conducted in the Isle of Man investigate local perceptions of a tourism industry in long-term decline: a development stage typically overlooked. Negative impacts of decline are revealed; including facilities loss, landscape erosion, and a heightened sense of peripherality. Together such impacts undermine local identity and attractiveness of place. Tourists are welcomed as they help to affirm the pride residents have in their island, create atmosphere, provide social interaction opportunities, stimulate positive emotions and combat negative stereotyping. Emphasised is the on-going importance of tourism impacts in a peripheral location. Practioner recommendations are therefore made calling attention to the need to more carefully manage the process of decline. Potential strategies for achieving this are signposted

Investigating the Electromechanical Behavior of Unconventionally Ferroelectric Hf0.5Zr0.5O2-Based Capacitors Through Operando Nanobeam X-Ray Diffraction

Understanding various aspects of ferroelectricity in hafnia-based nanomaterials is of vital importance for the development of future nonvolatile memory and logic devices. Here, the unconventional and weak electromechanical response of epitaxial La0.67Sr0.33MnO3/Hf0.5Zr0.5O2/La0.67Sr0.33MnO3 ferroelectric capacitors is investigated, via the sensitivity offered by nanobeam X-ray diffraction experiments during application of electrical bias. It is shown that the pristine rhombohedral phase exhibits a linear piezoelectric effect with piezoelectric coefficient (|d33|) ≈ 0.5–0.8 pmV−1. It is found that the piezoelectric response is suppressed above the coercive voltage. For higher voltages, and with the onset of DC conductivity throughout the capacitor, a second-order effect is observed. The work sheds light into the electromechanical response of rhombohedral Hf0.5Zr0.5O2 and suggests its (un)correlation with ferroelectric switching

The Extent and Role of Domestic Tourism in a Small Island: The Case of the Isle of Man

This article presents a case concerning microdomestic tourism on the Isle of Man, British Isles. Despite being a small island, research highlights that considerable domestic tourism occurs (referred to as microdomestic tourism to reflect the small island size and distinguish from wider British Isles tourism), including day trips and overnight stays. Participants identified such behavior as touristic, and distinct from other leisure activities. Qualitative interviews with residents explore the nature of and reasons for microdomestic tourism within a small island. Breaks from routine, entertaining friends and family, and exploring less well known landscapes are shown to underpin. Highlighted is that microdomestic tourism has a variety of potential benefits, which may counter some of the restrictions typically faced by a small island community. Support for an otherwise ailing tourism industry may help to protect facilities and infrastructure used by the wider community, maintain tourism capacity, and provide atmosphere attractive to foreign visitors

Narcissism normalisation: tourism influences and sustainability implications

The concept of narcissism normalisation suggests that individuals and societies are becoming more narcissistic due to various cultural influences. Tourism is reviewed here as one such possible influence. Exploitative, entitled and exhibitionistic tendencies associated with narcissism are wellestablished in tourism. Yet tourism is also an intimate, communal and satisfying activity which may counteract narcissism. Increases in narcissism have significant implications from a sustainable tourism perspective. Narcissism is associated with exploitative and entitled behaviours that over time cause significant harm to those people and landscapes that come into contact with. Narcissism appears to be incompatible with principles of sustainability and the challenges this poses for the industry are reviewed, while the opportunities are also explored. There are signs that narcissism, particularly those aspects relating to exhibitionism, can be co-opted to benefit sustainable development