Browsing by Subject "Coverage"
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Item Open Access Control and Optimization of Track Coverage in Underwater Sensor Networks(2007-12-14) Baumgartner, Kelli A. CrewsSensor network coverage refers to the quality of service provided by a sensor network surveilling a region of interest. So far, coverage problems have been formulated to address area coverage or to maintain line-of-sight visibility in the presence of obstacles (i.e., art-gallery problems). Although very useful in many sensor applications, none of the existing formulations address coverage as it pertains to target tracking by means of multiple sensors, nor do they provide a closed-form function that can be applied to the problem of allocating sensors for the surveilling objective of maximizing target detection while minimizing false alarms. This dissertation presents a new coverage formulation addressing the quality of service of sensor networks that cooperatively detect targets traversing a region of interest, and is readily applicable to the current sensor network coverage formulations. The problem of track coverage consists of finding the positions of n sensors such that the amount of tracks detected by at least k sensors is optimized. This dissertation studies the geometric properties of the network, addressing a deterministic track-coverage formulation and binary sensor models. It is shown that the tracks detected by a network of heterogeneous omnidirectional sensors are the geometric transversals of non-translates families of disks. A novel methodology based on cones and convex analysis is presented for representing and measuring sets of transversals as closed-form functions of the sensors positions and ranges. As a result, the problem of optimally deploying a sensor network with the aforementioned objectives can be formulated as an optimization problem subject to mission dynamics and constraints. The sensor placement problem, in which the sensors are placed such that track coverage is maximized for a fixed sensor network, is formulated as a nonlinear program and solved using sequential quadratic programming. The sensor deployment, involving a dynamic sensor network installed on non-maneuverable sonobuoys deployed in the ocean, is formulated as an optimization problem subject to inverse dynamics. Both a finite measure of the cumulative coverage provided by a sensor network over a fixed period of time and the oceanic-induced current velocity field are accounted for in order to optimize the dynamic sensor network configuration. It is shown that a state-space representation of the motions of the individual sensors subject to the current vector field can be derived from sonobuoys oceanic drift models and obtained from CODAR measurements. Also considered in the sensor model are the position-dependent acoustic ranges of the sensors due to the effects from heterogenous environmental conditions, such as ocean bathymetry, surface temporal variability, and bottom properties. A solution is presented for the initial deployment scheme of the non-maneuverable sonobuoys subject to the ocean's current, such that sufficient track coverage is maintained over the entire mission. As sensor networks are subject to random disturbances due to unforseen heterogenous environmental conditions propagated throughout the sensors trajectories, the optimal initial positions solution is evaluated for robustness through Monte Carlo simulations. Finally, the problem of controlling a network of maneuverable underwater vehicles, each equipped with an onboard acoustic sensor is formulated using optimal control theory. Consequently, a new optimal control problem is presented that integrates sensor objectives, such as track coverage, with cooperative path planning of a mobile sensor network subject to time-varying environmental dynamics.Item Open Access Systemic Sclerosis as an Indication for Autologous Hematopoietic Cell Transplantation: Position Statement from the American Society for Blood and Marrow Transplantation.(Biology of blood and marrow transplantation : journal of the American Society for Blood and Marrow Transplantation, 2018-06-25) Sullivan, Keith M; Majhail, Navneet S; Bredeson, Christopher; Carpenter, Paul A; Chatterjee, Soumya; Crofford, Leslie J; Georges, George E; Nash, Richard A; Pasquini, Marcelo C; Sarantopoulos, Stefanie; Storek, Jan; Savani, Bipin; St Clair, E WilliamSystemic sclerosis is a progressive inflammatory disease that is frequently fatal and has limited treatment options. High-dose chemotherapy with autologous hematopoietic cell transplantation (AHCT) has been evaluated as treatment for this disease in observational studies, multicenter randomized controlled clinical trials, and meta-analyses. On behalf of the American Society for Blood and Marrow Transplantation (ASBMT), a panel of experts in transplantation and rheumatology was convened to review available evidence and make a recommendation on AHCT as an indication for systemic sclerosis. Three randomized trials have compared the efficacy of AHCT with cyclophosphamide only, and all demonstrated benefit for the AHCT arm for their primary endpoint (improvement in the American Scleroderma Stem Cell versus Immune Suppression Trial, event-free survival in Autologous Stem Cell Transplantation International Scleroderma trial, and change in global rank composite score in Scleroderma: Cyclophosphamide or Transplantation trial). AHCT recipients also had better overall survival and a lower rate of disease progression. These findings have been confirmed in subsequent meta-analyses. Based on this high-quality evidence, the ASBMT recommends systemic sclerosis should be considered as a "standard of care" indication for AHCT. Close collaboration between rheumatologists and transplant clinicians is critical for optimizing patient selection and patient outcomes. Transplant centers in the United States are strongly encouraged to report patient and outcomes data to the Center for International Blood and Marrow Transplant Research on their patients receiving AHCT for this indication.Item Open Access Universal Health Coverage for the Poor and Informal Sector in Africa: A Health Financing Policy Analysis(2022) Hughes, Michelle ZoeBackground:In their pursuit of Universal Health Coverage (UHC), a challenge African countries face is extending health coverage to the poor and informal sector. This group accounts for a significant proportion of the population in most African countries, yet there is a wealth of evidence documenting their low health coverage and a contrasting paucity of data available to inform financing policy reform. This thesis intends to collect and apply data to this challenge, redressing this paucity and generating evidence on policies that support a fair, progressive realization of UHC.
Methods:I used a policy surveillance methodology to transform the text of health financing laws and policies into quantitative and qualitative data for analysis. I surveyed the 47 countries of the World Health Organization AFRO region with a codebook consisting of 28 questions relating to the coverage of the poor and informal sector. I answered questions using publicly available, country level documents. I used the data to (i) identify prevailing financing policies that provide health coverage to the poor and informal sector and (ii) present a comparative case analysis examining associations between health financing policies and essential health service coverage.
Results:Health insurance and user fees are predominant UHC financing approaches in Africa. 45 of 47 countries (96%) have health insurance policy and 34 countries (72%) have policy enforcing user fees. To help the poor and informal sector overcome these financial access barriers, countries use exemptions and subsidies. Of the 45 countries with health insurance, 18 (40%) exempt or subsidise premiums for the poor. Of the 34 countries with user fees, 18 (53%) exempt and/or subsidise user fees for the poor. Of the 41 countries with health service packages, 19 countries (46%) provide the health services for free. In general, there is a lack of targeted financing mechanisms for the informal sector.
Conclusions:Extending coverage to the poor and informal sector is a challenge within the broader context of expanding UHC in Africa. This study provides a comprehensive overview of financing policy solutions from within the continent and lays the foundation for further analyses to clarify what reforms work best.