UAV path planning optimization based on GNSS quality and mission requirements

One of the most crucial factors for the overall success of an Unmanned Aerial Vehicle (UAV) mission is navigation performance, which is severely affected in Global Navigation Satellite Systems (GNSS) challenging environments. A solution to this problem could come through path planning optimization. This paper investigates the impact that GNSS quality information included in the UAV path planning process would have on the overall UAV mission success rate (MSR) when flying through an urban canyon. Number of visible satellites and Horizontal Dilution of Precision (HDOP) in addition to mission-specific requirements are given as input to the Particle Swarm Optimization (PSO) algorithm to calculate the optimal path for two cases. One includes the GNSS observables, and the other does not. Optimal paths for three different altitudes are obtained. All paths are simulated by a GNSS signal simulator, including a comprehensive multipath model. GNSS data are collected by a hardware receiver for analysis of the UAV positioning error and GNSS availability. Mission failures cases are defined accordingly, and the overall mission success rate (MSR) of each scenario is assessed. By analyzing the findings, it is concluded that in 83% of cases, the path planning process that included GNSS information was able to increase the MSR. Also, the increase in MSR was bigger when flying at low altitude

A spectral study of gamma-ray emitting AGN

In this paper we present a statistical analysis of the gamma-ray spectra of flat-spectrum radio quasars (FSRQ) compared to those of BL Lacs. The average spectra and possible systematic deviations from power-law behaviour are investigated by summing up the intensity and the power-law fit statistic for both classes of objects. We also compare the time-averaged spectrum to that at the time of gamma-ray outbursts. The spectrum of the average AGN is softer than that of the extragalactic gamma-ray background. It may be that BL Lacs, which on average have a harder spectrum than FSRQs, make up the bulk of the extragalactic background. We also find apparent cut-offs at both low and high energies in the spectra of FSRQs at the time of gamma-ray outbursts. While the cut-off at high energies may have something to do with opacity, the cut-off at low energies may be taken as indication that the gamma-ray emission of FSRQs is not a one component spectrum.Comment: 8 pages, accepted for publication in A&

Develop a cost model to evaluate the economic benefit of remanufacturing based on specific technique

Remanufacturing is a process of recovering used products to a like-new condition. It can potentially achieve considerable economic, environmental and social benefits in many applications. However, its economic benefit varies for different products and remanufacturing processes. This research aims to develop a framework and cost model to quantitatively evaluate the benefits of remanufacturing techniques to assist the decision making on end-of-life strategies. Additive manufacturing-based remanufacturing process has been modelled first, then cost breakdown structure for the process has been created, and the cost model has been developed. Validation of the cost model has been conducted based on expert judgement, and a case study has been carried out by using the developed cost model to compare the benefit of remanufacturing a specified component or making a new one

Organising in the Anthropocene: An Ontological Outline for Ecocentric Theorising

As a response to anthropogenic ecological problems, a group of organisation scholars have acknowledged the importance of ecocentric theorising that takes materiality and non-human objects seriously. The purpose of this article is to examine the philosophical basis of cocentric organisation studies and develop an ontological outline for ecocentric theorising in the Anthropocene. The paper identifies the central premises of ecocentric organisations from the previous literature, and complements the theory with a set of ontological qualities common to all objects. The study draws on recent advances in object-oriented and ecological philosophies to present three essential qualities of objects, namely autonomy, uniqueness, and intrinsicality. The paper discusses how these qualities are critical in reclaiming the lost credibility and practical relevance of ecocentrism in both organisational theory and the sustainability sciences in general. To organise human activities in a sustainable manner in the new geological era, a new ontology is needed that not only includes materiality and non-humans in the analysis, but also leads to an ecologically and ethically broader understanding of ecospheric beings and their relationships

Global commitment towards sustainable energy

Energy is crucial to economic and social development and improves quality of life. However, fossil fuel energy produces greenhouse gases (GHGs) and cannot be sustained for a long time. It is essential to tackle these problems by moving towards renewable and sustainable energy. Some countries, including those in the Arabian Gulf region, are still in the appraisal stage of adopting different forms of renewable energy. This paper reviews the business potential and likely GHG reductions associated with adopting renewable energy in Oman. It is revealed that 1·9 Mt of annual carbon dioxide emissions could be cut by producing 10% of the country’s electricity from renewables. The paper further discusses the global sustainable energy commitment under the UN Framework Convention on Climate Change and reviews the 2030 targets of some countries that are high producers of GHGs. It is anticipated that if all these planned targets are achieved, the total sustainable energy contribution could grow by nearly 11 000 TWh by 2030. These plans provide guidance for those countries still preparing to submit their plans to the UN