LEO Augmentation in Large-Scale Ionosphere-Float PPP-RTK Positioning

Precise point positioning-real-time kinematic (PPP-RTK) positioning combines the advantages of PPP and RTK, which enables the integer ambiguity resolution (IAR) without requiring a reference station nearby. The ionospheric corrections are delivered to users to enable fast IAR. For large-scale networks, precise interpolation of ionospheric delays is challenging. The ionospheric delays are often independently estimated by the user, in the so-called ionosphere-float mode. The augmentation of low Earth orbit (LEO) satellites can bridge this shortcoming thanks to their fast speeds and the resulting rapid geometry change. Using 30-s real dual-frequency Global Positioning System (GPS) and Beidou Navigation Satellite System (BDS) observations within a large-scale network of thousands of kilometers, this contribution tests the effects of LEO augmentation using simulated dual-frequency LEO signals from the navigation-oriented LEO constellation, CentiSpace. Results showed that the LEO augmentation makes the solution convergence less sensitive to the original Global Navigation Satellite System (GNSS)-based model strength. The improvements in the convergence times are significant. For example, in the kinematic mode, the convergence time of the 90% lines of the GPS/BDS-combined ambiguity-float horizontal solutions to 0.05 m is shortened from more than 60 to 3.5 min, and that of the GPS-only partial ambiguity resolution (PAR)-enabled horizontal solutions is shortened from more than 20 to 4.5 min. In both the ambiguity-float and PAR-enabled cases, the 68.27% (1σ) lines of both the kinematic and static horizontal and height errors can converge to 0.05 m within 4 min, and for the 90% lines, within 6.5 min in all cases. The 90% line of the GPS/BDS/LEO combined PAR-enabled solutions can converge to 0.05 m within 2.5 and 3 min in the horizontal and up direction, respectively. Results also showed that enlarged projection of the mismodeled biases on the user coordinates were observed in the LEO-augmented scenario after convergence or ambiguity resolution. This is mainly due to the lower orbital height and low elevation angles of the LEO satellites, which requires further research when real LEO navigation signals are available

Bounding of double-differenced correlated errors of multi-GNSS observations using RTK for AV positioning

Integrity monitoring of autonomous vehicle (AV) localization is essential to guarantee their safety. In this process, satellite observation errors should be bounded using proper statistical methods to calculate a protection level that is neither optimistic nor overly conservative. Therefore, a realistic weighting function that is based on real data was developed in this research to achieve that balance. When using RTK as a positioning method, a real challenge is dealing with the cross-correlation between differenced observations. In this work, the overbounding parameters, i.e. the standard deviation (STD) and mean (bias) of the observation errors, were empirically computed for numerous combinations of different signals and frequencies from multiple GNSS constellations. the Two-Step Gaussian Bounding (TSGB) method is used as it could maintain overbounding after convolution from the observation domain to the position domain. Two empirical methods were designed to obtain the overbounding parameters and build the covariance (weighting) observation matrix using one full year of satellite observations. In the first method, a mapping function was utilised to re-compute the observation residuals from the slant direction to the zenith. Accordingly, a user can simply map them back along the observed satellites directions at different elevation angles (EAs). The correlation coefficients between correlated observations are derived based on the EAs of the studied satellites, so that they can be used in the stochastic model. In a second approach, the differenced residuals were categorized based on the EAs of both the pivot and other satellites in intervals of five degrees and building look-up tables. The correlation coefficients in this case were empirically calculated using Pearson’s Correlation Coefficient equation. The overbounding mean and STD of both code and phase observation errors for both approaches were in the range of 0.0003–1.369 m and 0.007–2.497 m, respectively. While the first approach provides a tight overbounding results, the second is more conservative

Tax Accounting for The Renewable Energy (Electricity) Act 2000: A Tax by Any Other Name Would Smell as Sweet

Australia has committed to reducing greenhouse gas emissions, and part of that commitment is the enactment of the Renewable Energy (Electricity) Act 2000 (Cth) (the REE Act). This article focuses on the Australian renewable Energy Target and how the REE Act impacts on the electrical generation industry to dilute greenhouse gas emissions. The research examines the market of trading ‘carbon credits’ produced under the provisions of the REE Act, which are known as Renewable Energy Credits (RECs), and views this as a taxation and subsidisation system. It aims to develop a clear understanding of the operations of the REE Act: how the REC system interacts with Australia’s two other main taxes – Income Tax and Goods and Services Tax; and how the trade in RECs may be treated in the accounts of the respective trading entities – the liable parties and the renewable energy electricity generators

Interfacial engineering of 2H‑MoS2/N-doped carbon composite for fast potassium interfacial storage

The 2H-MoS2 incorporated with N-doped carbon (2H-MoS2/NC) with high discharge capacity has attracted more research focus as an anode material for K-ion batteries (PIBs). However, large longitudinal lattice deformation at 2H-MoS2/NC heterointerfaces caused by interfacial intercalation of K ions negatively impacts the structural stability, which limits its cycling performance. In this paper, interfacial engineering has been applied to optimize the structural stability of 2H-MoS2/NC. By using first-principle simulation, the evolutions of longitudinal lattice deformation, K adsorption/diffusion performance/behaviour, interfacial strength, and electronic property with the interfacial interlayer spacing have been systematically explored. The results show that with the increase of interlayer spacing from 5.0 to 7.0 Å, the lattice deformation, interfacial strength, and K adsorption kinetics first decrease sharply with interlayer spacing in the range of 5.0–6.5 Å, and then they drop minorly at 6.5–7.0 Å. The K interfacial diffusion capability can be improved due to the decreased charge accumulation at interface that leads to weakened K–S bonding with a rising interlayer spacing. Based on variation of structural stability and K storage performance, an optimal interlayer spacing of 6.75 Å is confirmed. These findings can provide a solid theoretical basis and guidance for the experimental preparation of high-performance 2H-MoS2/NC electrode materials and further cultivate new concepts for the optimal design of two-dimensional composite electrode materials. Graphical Abstract: (Figure presented.

Exploring the Visual-Tactile Temporal Binding Window and Multisensory Influences on Sensorimotor Synchronization

Meaningful interaction with our environment relies upon timely integration of multisensory information and actions performed in synchrony with sensory input. This thesis examines the temporal binding window for visual-tactile integration using the simultaneity judgement task, and the influence of multisensory information on sensorimotor synchronization. Additionally, this thesis investigates functional connectivity between unisensory and multisensory neural regions during, and immediately following stimulus presentation, in the simultaneity judgement task to understand differences between simultaneous and non-simultaneous perceptio

Cultural dimensions and stock market response: analyzing the impact of covid-19 pandemic on individualism and power distance

The purpose of study is to analyze the stock market reaction to Covid-19 pandemic in framework of cultural diversity that is individualism and power distance. This study considered daily data of stock market, growth in Covid-19 confirm cases and cultural values for 40 countries from January 2020 to December 2021. The Covid 19 cases data were collected from the website of Corona-virus Resource Centre (JHU-CRC) John Hopkins University and other variables like GDP, economic freedom, stringency index from the WB, IMF and OXFORD COVID-19 Government Response Stringency index of the world. The average returns are negative and fluctuated during pandemic. The finding shows the presence of cultural effect as a moderator and indicates that stock markets are more affected during the pandemic where individualism and power distance is high. The study recommends the significance role of human behavior integrating the cultural differentiation and substantial repercussions for policy makers, academicians and investors

Drivers of geographical indication food supply chain performance: a B2B network perspective

This study aims to examine the role relational dynamics, grounded in the theories of social exchange and social capital, play within the context of geographic indication (GI) food supply chain network (FSCN) performance. A total of 30 qualitative interviews were undertaken with key informant stakeholders across a variety of organizations within Turkish GI FSCNs. An open, axial and selective grounded theory coding process was used for the analysis, teasing out critical themes that underpinned the conceptual framework. The findings identify the formal and informal mechanisms which govern GI FSCNs. These two forms of governance mechanisms influence network performance, which was found to comprise logistics, production, business and socio-economic performance dimensions. Transparency, GI traceability, trust and psychological contract violations were found to mediate the link between governance and network performance outcomes. To the best of the authors’ knowledge, this study is the first to explore GI FSCNs from the perspective of relationship marketing and through the lens of social exchange and social capital theory. Accordingly, both academics and practitioners can benefit from the study, as it unveils relevant relational factors underpinning such networks

Apps for Children with Disabilities: Effectiveness of Mobile Health Technology for Adherence and Engagement with Home Therapy Programmes

This thesis investigated the use of a commercially available therapy prescription app to deliver home programmes for children with disabilities in a randomised controlled trial. With no improvements in program adherence, and feedback from the children that the app was boring, a new gamified therapy app, Zingo, was then developed and tested specifically for children. The Zingo app was found to be fun and motivating for children with disabilities

Targeted Stimulation of Micropores by CS2 Extraction on Molecular of Coal

The targeted stimulation of micropores based on the transformation of coal’s molecular structure is proposed due to the chemical properties and difficult-to-transform properties of micropores. Carbon disulfide (CS2) extraction is used as a targeted stimulation to reveal the internal evolution mechanism of micropore transformation. The variations of microcrystalline structures and micropores of bituminous coal and anthracite extracted by CS2 were analyzed with X-ray diffraction (XRD), low-temperature carbon dioxide (CO2) adsorption, and molecular simulation. The results show that CS2 extraction, with the broken chain effect, swelling effect, and aromatic ring rearrangement effect, can promote micropore generation of bituminous coal by transforming the microcrystalline structure. Furthermore, CS2 extraction on bituminous coal can decrease the average micropore size and increase the micropore volume and area. The aromatic layer fragmentation effect of CS2 extraction on anthracite, compared to the micropore generation effect of the broken chain effect and swelling effect, can enlarge micropores more remarkably, as it induces an enhancement in the average micropore size and a decline in the micropore volume and area. The research is expected to provide a theoretical basis for establishing reservoir stimulation technology based on CS2 extraction