Cone-shaped Filter Research Articles

LAIK: Location-Specific Analysis to Infer Key Performance Indicators

Key Performance Indicators (KPIs) are important measures of the quality of service in cellular networks. There are multiple efforts by cellular carriers and 5G standardization on the use of crowdsourcing to minimize drive tests (MDT) and self-organize the network while improving KPIs via a user feedback loop. Since propagation highly depends upon the environment, readily-available geographical data could be coupled with the crowdsourced user data to infer performance. In this paper, we build a framework to infer KPIs by establishing a relationship between geographical data and crowdsourced channel measurements via neural networks. In particular, for a specific user location, we leverage delay spread measurements in the region to design a cone-shaped filter for the geographical and user data extraction. Then, a location-specific received signal power prediction is obtained via the neural network trained using the extracted geographical and user data. We study the impact of the angle chosen for the cone and various features selected on location-specific KPI prediction. We then leverage the location-specific inference by repeating the prediction over a set of locations in a region to infer the path loss in a given environment. In both types of KPI inference, we compare against state-of-the-art solutions and show that significant improvement in KPI prediction accuracy is achieved using the proposed strategy. Furthermore, for network planners, we show that our framework can use only geographical information to predict KPIs with a negligible error in user locations that lack signal quality data. By employing the proposed framework to predict location-specific and regional KPIs, we achieve an accurate estimation of network coverage and a 7-fold reduction in throughput estimation error compared to a state-of-the-art solution.

Effects of reverse deployment of cone-shaped vena cava filter on improvements in hemodynamic performance in vena cava

BackgroundCone-shaped vena cava filters (VCFs) are widely used to treat venous thromboembolism. However, in the long term, the problem of occlusion persists even after the filter is deployed. A previous study hypothesized that the reverse deployment of a cone-shaped VCFs may prevent filter blockage.MethodsTo explore this hypothesis, a comparative study of the traditional and reverse deployments of VCFs was conducted using a computational fluid dynamics approach. The distribution of wall shear stress (WSS) and shear stress-related parameters were calculated to evaluate the differences in hemodynamic effects between both conditions. In the animal experiment, we reversely deployed a filter in the vena cava of a goat and analyzed the blood clot distribution in the filter.ResultsThe numerical simulation showed that the reverse deployment of a VCF resulted in a slightly higher shear rate on the thrombus, and no reductions in the oscillating shear index (OSI) and relative residence time (RRT) on the vessel wall. Comparing the traditional method with the reversely deployed cases, the shear rate values is 16.49 and 16.48 1/s, respectively; the minimal OSI values are 0.01 and 0.04, respectively; in the vicinity of the VCF, the RRT values are both approximately 5 1/Pa; and the WSS is approximately 0.3 Pa for both cases. Therefore, the reverse deployment of cone-shaped filters is not advantageous when compared with the traditional method in terms of local hemodynamics. However, it is effective in capturing thrombi in the short term, as demonstrated via animal experiments. The reversely deployed cone-shaped filter captured the thrombi at its center in the experiments.ConclusionsThus, the reverse deployment of cone-shaped filters is not advantageous when compared with the traditional method in terms of local hemodynamics. Therefore, we would not suggest the reverse deployment of the cone-shaped filter in the vena cava to prevent a potentially fatal pulmonary embolism.

КОМП’ЮТЕРНЕ ПРОГНОЗУВАННЯ ПIДВИЩЕННЯ ЕФЕКТИВНОСТI РОБОТИ ШВИДКИХ БАГАТОШАРОВИХ ФIЛЬТРIВ ДЛЯ АДСОРБЦIЙНОЇ ДООЧИСТКИ ВОДИ

A model of the adsorption purification of water from impurities in rapid multilayer cone-shaped filters with piecewisehomogeneous porous loads with a constant filtration rate taking into account the removal of part of the heat on the surfaces of division of layers is formulated. The proposed model provides an opportunity to conduct computer experiments to study the change in the concentrations of impurities in the filtration flow and adsorbed on the surface of the adsorbent load during physical and chemical adsorption, temperature, characteristics of piecewise-homogeneous porous loads along the filter height and based on their prediction of optimal adsorbent use and increasing the duration of filters.

Computer Prediction of Adsorption Water Purification Process in Rapid Cone-Shaped Filters

In the paper a mathematical model for computer predicting the process of adsorption purification of water from impurities in rapid filters taking into account changes in the temperature of the filtration flow along the height of the filter while observing the constant filtration rate is formulated. Analgorithm for numerically-asymptotic approximation of solution of the corresponding nonlinear singularly perturbed boundary value problem for a model region of a conical shape, bounded two equipotential surfaces and a surface flow, is developed. The proposed model allows through computer experiments to investigate changes in the characteristics of porous loads (filtration coefficients, active porosity), to predict the optimal variants for using adsorbents, and increasing the duration of the filters operation due to the choice of their shape, taking into account the effect on the process of adsorption purification ofwater not only changes in the filtration rate flow along the height of the filter, but also the temperature.

A novel deployment design of vena cava filters might be the solution to their blockage problem

The blockage of a vena cava filter (VCF) by the captured blood clots presents a serious problem to the patients. Commercially available cone-shaped VCFs such as the Gunther Tulip filter has an inherent structural flaw that leads the captured blood clots to be trapped in their front spire areas where the flow-induced shear stress is relatively low so that the clots cannot dissolve fast enough and will accumulate, gradually block the central passages of the filters. It is well known that for a Hagen–Poiseuille flow in a circular tube, the flow-induced shear stress is highest at the wall of the tube and lowest along its axis. Herein, we hypothesize that by reversely deploying a cone-shaped filter in the vena cava, the filter’s blockage problem might be prevented. First of all, this kind of deployment scenario can force the captured blood clots to stay in the peripheral areas of the vena cava and keep the central passage of the filter unblocked. Secondly, this scenario can expose the captured blood clots to relatively high shear stress that may dissolve the clots faster.

3-D FIR Cone-Shaped Filter Design by a Nest of McClellan Transformations and Its Variable Design

In this paper, the technique of a nest of McClellan transformations is proposed for the design of 3-D FIR cone-shaped filters. First, a transformation subfilter for fan-type mapping is found. Then the cosine term of a frequency variable of the above transformation subfilter is replaced by an embedded transformation subfilter which possesses circular contours. The technique stated above is also extended to design 3-D FIR variable cone-shaped filters such that the inclination of the cone-shaped filters can be adjusted online. Moreover, an efficient structure is proposed for the implementation of the designed filters. Several examples will be presented to demonstrate the effectiveness of the proposed method.

A Design Method for 3-D FIR Cone-Shaped Filters Based on the McClellan Transformation

This paper presents an efficient technique for designing three-dimensional (3-D) finite-impusle-response (FIR) digital filters having cone-shaped magnitude response. The McClellan transformation method is used as basis of the design. The new approach proposes a closed form solution for the transform coefficients of the mapping function. A simultaneous determination of the 1-D cutoff frequency of the prototype filter is also considered. The newly obtained relations for the transform parameters are very simple and depend on the angle of inclination of the cone. Additionally, the analytical expressions for the impulse response coefficients of the transformation subfilter are also derived. The behavior of the transformation function is examined, followed by several detailed examples with different input specifications of designed 3-D cone filters.

Three-dimensional cone filter banks

Three dimensional (3-D) narrow cone-shaped filter passbands are ideally required for the selective filtering of sampled broad-band 3-D plane waves on the basis of their directions of arrival. A method is proposed for approximating narrow 3-D cone-shaped passbands using a 3-D cone-filter-bank structure in which the subbands consist of band limited 3-D narrow-band infinite impulse response (IIR) beam filters having 3-D uniform bandwidths that are approximately proportional to their distance from the origin in the 3-D frequency space. The 3-D beam filters may be realized from a cascade of 3-D IIR frequency-planar filters. It is shown that the proposed 3-D cone filter bank achieves low distortion of broad-band passband 3-D plane waves, and significant attenuation of broad stopband plane waves.