Stochastic Particle Flow for Nonlinear High-Dimensional Filtering Problems

A series of novel filters for probabilistic inference that propose an alternative way of performing Bayesian updates, called particle flow filters, have been attracting recent interest. These filters provide approximate solutions to nonlinear filtering problems. They do so by defining a continuum of densities between the prior probability density and the posterior, i.e. the filtering density. Building on these methods' successes, we propose a novel filter. The new filter aims to address the shortcomings of sequential Monte Carlo methods when applied to important nonlinear high-dimensional filtering problems. The novel filter uses equally weighted samples, each of which is associated with a local solution of the Fokker-Planck equation. This hybrid of Monte Carlo and local parametric approximation gives rise to a global approximation of the filtering density of interest. We show that, when compared with state-of-the-art methods, the Gaussian-mixture implementation of the new filtering technique, which we call Stochastic Particle Flow, has utility in the context of benchmark nonlinear high-dimensional filtering problems. In addition, we extend the original particle flow filters for tackling multi-target multi-sensor tracking problems to enable a comparison with the new filter

Reliability and Economic Efficiency Analysis of 4-Leg Inverter Compared with 3-Leg Inverters

The 4-leg inverter can adjust the load current or output voltage even under unbalanced load conditions, but it is known that the additional switch arm to the 3-leg inverter can increase the overall cost and the failure rate. This paper aims to analyze the failure rate and mean time between failures (MTBF) of 3-leg inverters and 4-leg inverters using part count failure analysis (PCA) and fault-tree analysis (FTA), and to compare the price of the inverters. The FTA can analyze the failure rate, including the type, number and connection status of the circuit components, and moreover the redundancy effect of the 4-leg inverter. For more accurate failure-rate prediction, the failure rate and MTBF of the 4-leg inverter according to the lifecycle of the controller are analyzed. Finally, by comparing the price of 3-leg inverters and 4-leg inverters using the cost model of major parts, the degree of reliability improvement against price increase is quantitatively analyzed

Representative images of (A) cardioembolic (CE) and (B) non-CE risk factors in patients with non-valvular atrial fibrillation.

<p>In intracranial arterial stenosis (B), the yellow arrow indicates the atherosclerotic stenosis lesion on magnetic resonance angiography. LAA = left atrial appendage.</p

The burden of (A) cardioembolic (CE), (B) non-CE, and (C) composite risk factors of ischemic stroke according to CHA₂DS₂-VASc scores.

<p>CE risk factors: intracardiac thrombus, dense spontaneous echo contrast, or low left atrial appendage flow velocity (mean peak flow velocity ≤20 cm/sec). Non-CE risk factors: intracranial arterial stenosis, significant carotid stenosis, or complex aortic plaque. (Overall: n = 401; CHA₂DS₂-VASc score, 0: n = 14, 1: n = 60, 2: n = 74, 3: n = 83, 4: n = 94, 5: n = 42, ≥6: n = 34).</p

Distribution of patients and CE and non-CE risk factors of ischemic stroke according to CHA₂DS₂-VASc scores and risk categories.

<p>Distribution of patients and CE and non-CE risk factors of ischemic stroke according to CHA₂DS₂-VASc scores and risk categories.</p

Patient characteristics.

<p>Patient characteristics.</p

Logistic regression analyses of the presence of CE or non-CE stroke risk factors in patients with non-valvular atrial fibrillation.

<p>Logistic regression analyses of the presence of CE or non-CE stroke risk factors in patients with non-valvular atrial fibrillation.</p

Coronary artery calcium scores and non-cardioembolic (non-CE) risk factors of ischemic stroke.

<p>(A) Comparison of coronary artery calcium scores between low/intermediate and high risk categories of CHA₂DS₂-VASc score. (B) Proportion of patients with non-cardioembolic (non-CE) risk factors according to risk categories of the CHA₂DS₂-VASc score and coronary artery calcium score.</p