scholarly journals A mixed-step algorithm for the approximation of the stationary regime of a diffusion

2014 ◽  
Vol 124 (1) ◽  
pp. 522-565 ◽  
Author(s):  
Gilles Pagès ◽  
Fabien Panloup
Keyword(s):  
Stationary Regime ◽  
Step Algorithm

Application of Mathematical Modeling during Monitoring and Optimization of Non-Stationary Regime of Oil Well

2016 ◽  
Vol 11 (1) ◽  
pp. 53-59
Author(s):  
A.S. Topolnikov
Keyword(s):  
Mathematical Modeling ◽  
Model Problem ◽  
Cylindrical Tube ◽  
Field Measurements ◽  
Stationary Flow ◽  
Stationary Regime ◽  
Oil Well ◽  
Time Duration ◽  
Typical Time ◽  
Radial Model

The paper presents results of modeling of periodical regime of oil well for the purpose of monitoring and optimization of its operation. To describe non-stationary flow in the reservoir a planar-radial model of filtration is employed. The flow of multiphase flux in the well elements (casing, tubing, annulus) is described by 1D Navier-Stoks equations. The pump work is modelled by specification of its rate-head curve. To estimate the typical time duration of the processes in the well and in the reservoir a solution of a model problem for cylindrical tube is given. Through the examples a solution of a problem of optimization of periodical regime of oil wells is demonstrated. The comparison with field measurements is presented.

scholarly journals Two-step machine learning method for the rapid analysis of microvascular flow in intravital video microscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ossama Mahmoud ◽  
Mahmoud El-Sakka ◽  
Barry G. H. Janssen
Keyword(s):  
Machine Learning ◽  
Blood Flow ◽  
Human Error ◽  
Image Data ◽  
Video Microscopy ◽  
Microvascular Blood Flow ◽  
Image Processing Algorithm ◽  
Step Algorithm ◽  
3D Cnn

AbstractMicrovascular blood flow is crucial for tissue and organ function and is often severely affected by diseases. Therefore, investigating the microvasculature under different pathological circumstances is essential to understand the role of the microcirculation in health and sickness. Microvascular blood flow is generally investigated with Intravital Video Microscopy (IVM), and the captured images are stored on a computer for later off-line analysis. The analysis of these images is a manual and challenging process, evaluating experiments very time consuming and susceptible to human error. Since more advanced digital cameras are used in IVM, the experimental data volume will also increase significantly. This study presents a new two-step image processing algorithm that uses a trained Convolutional Neural Network (CNN) to functionally analyze IVM microscopic images without the need for manual analysis. While the first step uses a modified vessel segmentation algorithm to extract the location of vessel-like structures, the second step uses a 3D-CNN to assess whether the vessel-like structures have blood flowing in it or not. We demonstrate that our two-step algorithm can efficiently analyze IVM image data with high accuracy (83%). To our knowledge, this is the first application of machine learning for the functional analysis of microvascular blood flow in vivo.

scholarly journals Comparison of the thermal performance between conventional and cob building

2019 ◽  
Vol 111 ◽  
pp. 03003
Author(s):  
Kaoutar Zeghari ◽  
Hasna Louahlia ◽  
Malo Leguern ◽  
Mohamed Boutouil ◽  
Hamid Gualous ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Behaviour ◽  
Calculation Method ◽  
Building Materials ◽  
Residential Building ◽  
Local Heat ◽  
Energy Performance ◽  
Stationary Regime ◽  
Thermal Regulation ◽  
Climate Data

The appliance of sustainable development approach in building has urged construction industry to adopt proper measurements to protect environment and reduce residential building energy consumption and CO2 emissions. Thus, an increasing interest in alternative building materials has developed including the use of bio-based materials such as cob which is studied in this paper. In the previous work, many experimental and numerical studies have been carried out to characterize thermal behaviour of earth buildings, reduce its thermal conductivity and water content. In this paper, an experimental study is carried out to determine the thermal properties and energy performance of cob building. Cob samples within different soil and fiber contents are studied using an experimental set up instrumented with flux meters and micro-thermocouples in order to evaluate the local heat flux and thermal conductivity during stationary regime. The results are analysed and compared to deduce the performant mixes in terms of thermal behaviour while respecting the French thermal regulation. A static thermal simulation based on RT 2012 calculation method (the official French calculation method for the energy performance of new residential and commercial buildings according to France thermal regulation) is used to compare energy performance between conventional and cob building using the French climate data base .

scholarly journals Boundary behavior and product-form stationary distributions of jump diffusions in the orthant with state-dependent reflections

2008 ◽  
Vol 40 (02) ◽  
pp. 529-547
Author(s):  
Francisco J. Piera ◽  
Ravi R. Mazumdar ◽  
Fabrice M. Guillemin
Keyword(s):  
Random Fields ◽  
Diffusion Coefficients ◽  
Boundary Behavior ◽  
Stationary Regime ◽  
Product Form ◽  
Local Times ◽  
Nonnegative Orthant ◽  
State Dependent ◽  
The Times ◽  
And Diffusion

In this paper we consider reflected diffusions with positive and negative jumps, constrained to lie in the nonnegative orthant of ℝ n . We allow for the drift and diffusion coefficients, as well as for the directions of reflection, to be random fields over time and space. We provide a boundary behavior characterization, generalizing known results in the nonrandom coefficients and constant directions of the reflection case. In particular, the regulator processes are related to semimartingale local times at the boundaries, and they are shown not to charge the times the process expends at the intersection of boundary faces. Using the boundary results, we extend the conditions for product-form distributions in the stationary regime to the case when the drift and diffusion coefficients, as well as the directions of reflection, are random fields over space.

scholarly journals Formal Codesign Methodology with Multistep Partitioning

VLSI Design ◽  
1998 ◽  
Vol 7 (4) ◽  
pp. 401-423 ◽  
Author(s):  
Vincenza Carchiolo ◽  
Michele Malgeri ◽  
Giuseppe Mangioni
Keyword(s):  
Formal Description ◽  
Formal Description Technique ◽  
Trade Off ◽  
Target Architecture ◽  
Design Cycle ◽  
Formal Basis ◽  
Step Algorithm ◽  
Description Technique ◽  
Hardware Performance

A codesign methodology is proposed which is suitable for control-dominated systems but can also be extended to more complex ones. Its main purpose is to optimize the trade-off between hardware performance and software reprogrammability and reconfigurability. The methodology proposed intends to cover the development of the whole system. It deals in greater detail with the steps that can be made without the need for any particular assumption regarding the target architecture. These steps concern splitting up the specification of the system into a set of individually synthesizable elements, and then grouping them for the subsequent mapping stage. In order to decrease the complexity of each partitioning attempt, a two step algorithm is proposed, thus permitting a wide exploration of possible solutions. The methodology is based on the TTL language, an extension of the T-LOTOS Formal Description Technique which provides a large amount of operators as well as a formal basis. Finally, an example pointing out the complete design cycle, excepting the allocation stage is provided.

scholarly journals Development and validation of a sequential two-step algorithm for the screening of individuals with potential polycythaemia vera

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Miguel Piris-Villaespesa ◽  
Alberto Álvarez-Larrán ◽  
Adolfo Saez-Marín ◽  
Claudia Nuñez-Torrón ◽  
Gloria Muñoz-Martin ◽  
...  
Keyword(s):  
Mutation Screening ◽  
Roc Curves ◽  
Polycythaemia Vera ◽  
Normal Ranges ◽  
Screening Algorithm ◽  
Number Of Patients ◽  
Step Algorithm ◽  
Development And Validation ◽  
Diagnostic Criterion ◽  
Selection Of

AbstractIn 2016, the WHO included haemoglobin values within normal ranges as a diagnostic criterion for Polycythaemia Vera (PV). Since then, concerns have arisen that a large number of patients are undergoing unnecessary screening for PV. To address this issue, we estimated the prevalence of JAK2 p.V617F in individuals with elevated haemoglobin or haematocrit and developed and validated a screening algorithm for PV. A total of 15,366 blood counts performed in seven non-consecutive days were reviewed, of which 1001 were selected for subsequent JAK2 p.V617F mutation screening. Eight (0.8%) new JAK2 p.V617F-mutated cases were detected. From ROC curves, a two-step algorithm was developed based on the optimal cut-off for the detection of the JAK2 p.V617F mutation. The algorithm was prospectively validated in an independent cohort of 15,298 blood counts. A total of 1595 (10.4%) cases met the criterion for haemoglobin or haematocrit, of whom 581 passed to step 2 (3.8% of the total). The JAK2 p.V617F mutation was detected in 7 of the 501 patients tested, which accounts for 0.04% of the total cohort and 0.4% of patients with erythrocytosis. In conclusion, this data show that our two-step algorithm improves the selection of candidates for JAK2 p.V617F testing.

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