19,251 research outputs found

    Time-Domain Data Fusion Using Weighted Evidence and Dempster–Shafer Combination Rule: Application in Object Classification

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    To apply data fusion in time-domain based on Dempster–Shafer (DS) combination rule, an 8-step algorithm with novel entropy function is proposed. The 8-step algorithm is applied to time-domain to achieve the sequential combination of time-domain data. Simulation results showed that this method is successful in capturing the changes (dynamic behavior) in time-domain object classification. This method also showed better anti-disturbing ability and transition property compared to other methods available in the literature. As an example, a convolution neural network (CNN) is trained to classify three different types of weeds. Precision and recall from confusion matrix of the CNN are used to update basic probability assignment (BPA) which captures the classification uncertainty. Real data of classified weeds from a single sensor is used test time-domain data fusion. The proposed method is successful in filtering noise (reduce sudden changes—smoother curves) and fusing conflicting information from the video feed. Performance of the algorithm can be adjusted between robustness and fast-response using a tuning parameter which is number of time-steps(ts)

    Coordinating monetary and fiscal policies: a role for rules?

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    The chapter argues for rules to coordinate monetary and fiscal policies. But the rules are rule like only in imposing forward-looking behaviour, while they allow the discretion to respond to shocks. They would serve to anchor expectations, and align private sector actions with desired outcomes. Many countries have used rules, but credible rules have to be suited to a country’s circumstances, which include both structure and political economy. These aspects help to explain past policy choices and outcomes in India, such as the relatively low inflation, even though monetary policy was not autonomous. Prices were kept down partly through administrative measures and subsidy schemes. This led to distortions that lowered efficiency and growth. The constraints need to be stricter for fiscal compared to monetary policy, in order to restrain the competitive populism of elected governments. If fiscal-deficit zone targeting restrains government consumption expenditure while protecting essential expenditure on physical and human capital, it would become possible to lower Indian real interest rates closer to world levels. Recent advances in the theory of monetary policy show how the CB can influence the real interest rate in the short- to medium-run, taking account of expected inflation in setting nominal interest rates while smoothing the latter. Exchange rate policy could also be further fine-tuned to fulfil the objectives of stabilising prices, stimulating exports, and preventing a currency crisis. Since accountability, in a democratic polity, forces the CB to keep inflation low, a weak constraint on the CB, such as medium-term inflation zone targeting, is credible. This would allow productivity improvement to decrease inflation, under expanding potential output.monetary fiscal policy coordination, rules, constrained discretion

    The Gravitational Constant as a quantum mechanical expression

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    A quantitatively verifiable expression for the Gravitational Constant is derived in terms of quantum mechanical quantities. This derivation appears to be possible by selecting a suitable physical process in which the transformation of the equation of motion into a quantum mechanical wave equation can be obtained by Einstein's geodesic approach. The selected process is the pi-meson, modeled as the one-body equivalent of a two-body quantum mechanical oscillator in which the vibrating mass is modeled as the result of the two energy fluxes from the quark and the antiquark. The quantum mechanical formula for the Gravitational Constant appears to show a quantitatively verifiable relationship with the Higgs boson as conceived in the Standard Model.Comment: 17 page

    Gamma-ray burst afterglows

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    Extended, fading emissions in multi-wavelength are observed following Gamma-ray bursts (GRBs). Recent broad-band observational campaigns led by the Swift Observatory reveal rich features of these GRB afterglows. Here we review the latest observational progress and discuss the theoretical implications for understanding the central engine, composition, and geometric configuration of GRB jets, as well as their interactions with the ambient medium.Comment: References added, accepted for publication in Advances in Space Researc

    Modelling public transport accessibility with Monte Carlo stochastic simulations: A case study of Ostrava

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    Activity-based micro-scale simulation models for transport modelling provide better evaluations of public transport accessibility, enabling researchers to overcome the shortage of reliable real-world data. Current simulation systems face simplifications of personal behaviour, zonal patterns, non-optimisation of public transport trips (choice of the fastest option only), and do not work with real targets and their characteristics. The new TRAMsim system uses a Monte Carlo approach, which evaluates all possible public transport and walking origin-destination (O-D) trips for k-nearest stops within a given time interval, and selects appropriate variants according to the expected scenarios and parameters derived from local surveys. For the city of Ostrava, Czechia, two commuting models were compared based on simulated movements to reach (a) randomly selected large employers and (b) proportionally selected employers using an appropriate distance-decay impedance function derived from various combinations of conditions. The validation of these models confirms the relevance of the proportional gravity-based model. Multidimensional evaluation of the potential accessibility of employers elucidates issues in several localities, including a high number of transfers, high total commuting time, low variety of accessible employers and high pedestrian mode usage. The transport accessibility evaluation based on synthetic trips offers an improved understanding of local situations and helps to assess the impact of planned changes.Web of Science1124art. no. 709

    Qualitative Research: A Grounded Theory Example and Evaluation Criteria

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    The qualitative research paradigm, although occasionally applied, is not widely discussed in agribusiness and agricultural economics literature. The primary goals of this paper are (a) to present insights into qualitative research approaches and processes by outlining grounded theory as an example of a systematic and rigorous qualitative approach, and (b) to discuss criteria for scientific rigor applicable to qualitative research. In addition, assessing qualitative research is demonstrated by using a published example.management research, methodology, qualitative research methods, reliability, validity, Research Methods/ Statistical Methods,

    Predicting spatial spread of rabies in skunk populations using surveillance data reported by the public

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    Background: Prevention and control of wildlife disease invasions relies on the ability to predict spatio-temporal dynamics and understand the role of factors driving spread rates, such as seasonality and transmission distance. Passive disease surveillance (i.e., case reports by public) is a common method of monitoring emergence of wildlife diseases, but can be challenging to interpret due to spatial biases and limitations in data quantity and quality. Methodology/Principal findings: We obtained passive rabies surveillance data from dead striped skunks (Mephitis mephitis) in an epizootic in northern Colorado, USA. We developed a dynamic patch-occupancy model which predicts spatio-temporal spreading while accounting for heterogeneous sampling. We estimated the distance travelled per transmission event, direction of invasion, rate of spatial spread, and effects of infection density and season. We also estimated mean transmission distance and rates of spatial spread using a phylogeographic approach on a subsample of viral sequences from the same epizootic. Both the occupancy and phylogeographic approaches predicted similar rates of spatio-temporal spread. Estimated mean transmission distances were 2.3 km (95% Highest Posterior Density (HPD95): 0.02, 11.9; phylogeographic) and 3.9 km (95% credible intervals (CI95): 1.4, 11.3; occupancy). Estimated rates of spatial spread in km/year were: 29.8 (HPD95: 20.8, 39.8; phylogeographic, branch velocity, homogenous model), 22.6 (HPD95: 15.3, 29.7; phylogeographic, diffusion rate, homogenous model) and 21.1 (CI95: 16.7, 25.5; occupancy). Initial colonization probability was twice as high in spring relative to fall. Conclusions/Significance: Skunk-to-skunk transmission was primarily local (< 4 km) suggesting that if interventions were needed, they could be applied at the wave front. Slower viral invasions of skunk rabies in western USA compared to a similar epizootic in raccoons in the eastern USA implies host species or landscape factors underlie the dynamics of rabies invasions. Our framework provides a straightforward method for estimating rates of spatial spread of wildlife diseases
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