Application of local and global sensitivity analysis methods to a north sea hydrodynamic model – study case of sffshore blue mussels and seaweed farms

Increasing demand for marine resources is a significant concern in today's world due to the limited availability of resources and the rapid population growth. The multi-use of offshore platforms has been introduced as a sustainable solution for resource utilization by many countries worldwide. However, researches are still being carried out to check the feasibility of these offshore platforms in aquaculture activities, renewable energy generation, tourism, and many other sectors. Before designing these infrastructures, it is essential to identify the suitable marine environments for each activity based on the required conditions and characteristics of the marine environments. Thus, numerical models play a vital role in simulating these marine environments and consequently will be used as a decision-making tool in feasibility studies and operational activities. The calibration of these numerical models is essential to have more reliable model outputs. However, these numerical models have many inputs parameters and physical variables on which the outputs depend. Sensitivity analysis can reduce the effort to calibrate complex numerical models with many input parameters by identifying the most influential inputs to an output variable. The main objective of the current research was to select the most significant input parameters to two selected outputs of a hydrodynamic model. DCSM is a hydrodynamic model developed for the North Sea by Deltares using the D-Flow FM model suite of Delft3D. Two selected local and global sensitivity analysis methods were applied to the above hydrodynamic model to test the sensitivities of temperature and current velocities to a selected subset of input parameters. The Morris method is used as a screening method to identify the order of the significance of input parameters. The variance-based Sobol’ method was used in global sensitivity analysis for the input parameters screened from the Morris method

Federated learning for enhanced sensor reliability of automated wireless networks

Abstract. Autonomous mobile robots working in-proximity humans and objects are becoming frequent and thus, avoiding collisions becomes important to increase the safety of the working environment. This thesis develops a mechanism to improve the reliability of sensor measurements in a mobile robot network taking into the account of inter-robot communication and costs of faulty sensor replacements. In this view, first, we develop a sensor fault prediction method utilizing sensor characteristics. Then, network-wide cost capturing sensor replacements and wireless communication is minimized subject to a sensor measurement reliability constraint. Tools from convex optimization are used to develop an algorithm that yields the optimal sensor selection and wireless information communication policy for aforementioned problem. Under the absence of prior knowledge on sensor characteristics, we utilize observations of sensor failures to estimate their characteristics in a distributed manner using federated learning. Finally, extensive simulations are carried out to highlight the performance of the proposed mechanism compared to several state-of-the-art methods

Immune compromise in HIV-1/HTLV-1 coinfection with paradoxical resolution of CD4 lymphocytosis during antiretroviral therapy: a case report

Human immunodeficiency virus type-1 (HIV-1) and human T lymphotropic virus type-1 (HTLV-1) infections have complex effects on adaptive immunity, with specific tropism for, but contrasting effects on, CD4 T lymphocytes: depletion with HIV-1, proliferation with HTLV-1. Impaired T lymphocyte function occurs early in HIV-1 infection but opportunistic infections (OIs) rarely occur in the absence of CD4 lymphopenia. In the unusual case where a HIV-1 infected individual with a high CD4 count presents with recurrent OIs, a clinician is faced with the possibility of a second underlying comorbidity. We present a case of pseudo-adult T cell leukemia/lymphoma (ATLL) in HIV-1/HTLV-1 coinfection where the individual fulfilled Shimoyama criteria for chronic ATLL and had pulmonary Mycobacterium kansasii, despite a high CD4 lymphocyte count. However, there was no evidence of clonal T-cell proliferation by T-cell receptor gene rearrangement studies nor of monoclonal HTLV-1 integration by high-throughput sequencing. Mutually beneficial interplay between HIV-1 and HTLV-1, maintaining high level HIV-1 and HTLV-1 viremia and proliferation of poorly functional CD4 cells despite chronicity of infection is a postulated mechanism. Despite good microbiological response to antimycobacterial therapy, the patient remained systemically unwell with refractory anemia. Subsequent initiation of combined antiretroviral therapy led to paradoxical resolution of CD4 T lymphocytosis as well as HIV-1 viral suppression and decreased HTLV-1 proviral load. This is proposed to be the result of attenuation of immune activation post-HIV virological control. This case illustrates the importance of screening for HTLV-1 in HIV-1 patients with appropriate clinical presentation and epidemiological risk factors and explores mechanisms for the complex interactions on HIV-1/HTLV-1 adaptive immunity

Downward approach for streamflow estimation, forecasting for small-scale to large-scale catchments: Learning from data.

Ph.DDOCTOR OF PHILOSOPH

Narrow escape in composite domains forming heterogeneous networks

Cellular networks are often composed of thin tubules connecting much larger node compartments. These structures serve for active or diffusion transport of proteins. Examples are glial networks in the brain, the endoplasmic reticulum in cells or dendritic spines located on dendrites. In this latter case, a large ball forming the head is connected by a narrow passage. In all cases, how the transport of molecules, ions or proteins is regulated determines the time scale of chemical reactions or signal transduction. In the present study, based on modeling diffusion in three dimensions, we compute the mean time for a Brownian particle to reach a narrow target inside such a composite network made of tubules connected to spherical nodes. We derive asymptotic formulas by solving a mixed Neumann-Dirichlet boundary value problem with small Dirichlet part. We first consider the case of a network domain organized in a 2-D lattice structure that consists of spherical ball compartments connected via narrow cylindrical passages. When there is a single target we derive a matrix equation for each Mean First Passage Time (MFPT) averaged over each spherical compartment. We then consider a composite domain consisting of a spherical head-like domain connected to a large cylinder via a narrow cylindrical neck. For Brownian particles starting within the narrow neck, we derive formulas for the MFPT to reach a target on the spherical head. When diffusing particles can be absorbed upon hitting additional absorbing boundaries of the large cylinder, we compute the probability and conditional MFPT to reach a target. We compare these formulas with numerical solutions of the mixed boundary value problem and with Brownian simulations. To conclude, the present analysis reveals that the mean arrival time, driven by diffusion in heterogeneous networks, is controlled by the target and narrow passage sizes.Comment: 33 pages and 13 figure

CONTROLLING DISSOCIATIVE DOUBLE IONIZATION OF ETHANE WITH ELLIPTICAL POLARIZED STRONG FIELDS

Laser control of chemical reactions has been a hot topic in recent years. Ethane, which has several dissociative double ionization channels under strong laser fields has been subjected to intense investigation. With the aid of newly developed coincidence detection imaging system, we demonstrate that the branching ratios of dissociative double ionization channels of ethane can be controlled by varying the ellipticity of the intense ultrashort laser pulses. The Methyl ion formation channel and proton formation channel show a significant yield changes, producing the highest and lowest at ellipticity of 0.6 respectively. We attribute such a control to both angle dependent ionization and intensity dependent ionization to excited dication states