scholarly journals Optimal Control of a PDE Model of an Invasive Species in a River

Mathematics ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 975
Author(s):  
Rebecca Pettit ◽  
Suzanne Lenhart
Keyword(s):  
Optimal Control ◽  
Invasive Species ◽  
Management Strategy ◽  
Discharge Rate ◽  
Water Discharge ◽  
Invasive Population ◽  
Cross Sectional ◽  
Flow Rates ◽  
Pde Model ◽  
The Cost

Managing invasive species in rivers can be assisted by appropriate adjustment of flow rates. Using a partial differential equation (PDE) model representing an invasive population in a river, we investigate controlling the water discharge rate as a management strategy. Our goal is to see how controlling the water discharge rate will affect the invasive population, and more specifically how water discharges may force the invasive population downstream. We complete the analysis of a flow control problem, which seeks to minimize the invasive population upstream while minimizing the cost of this management. Using an optimality system, consisting of our population PDE, an adjoint PDE, and corresponding optimal control characterization, we illustrate some numerical simulations in which parameters are varied to determine how far upstream the invasive population reaches. We also change the river’s cross-sectional area to investigate its impact on the optimal control.

A diffusion process model for the optimal operation of a reservoir system

1975 ◽  
Vol 12 (4) ◽  
pp. 859-863 ◽  
Author(s):  
Stanley R. Pliska
Keyword(s):  
Optimal Control ◽  
Diffusion Process ◽  
Process Model ◽  
Discharge Rate ◽  
Water Discharge ◽  
Optimal Operation ◽  
Water Levels ◽  
Control Problems ◽  
Release Rates ◽  
Controlled Diffusion

The water level in a reservoir is modelled as a controlled diffusion process on a compact interval of the real line. The problem is to control the water discharge rate so as to minimise the expected costs, which depend upon the histories of the water levels and release rates. The form of the optimal control is studied for two general classes of reservoir control problems.

Long-term dispersion of contaminants in small estuaries

1977 ◽  
Vol 82 (1) ◽  
pp. 129-146 ◽  
Author(s):  
Ronald Smith
Keyword(s):  
Transverse Shear ◽  
Discharge Rate ◽  
Water Discharge ◽  
Vertical Shear ◽  
Tidal Elevation ◽  
Cross Sectional ◽  
Dominant Mechanism ◽  
Contaminant Dispersion ◽  
Fresh Water Discharge

It is shown that the use of axes moving with the tide (Shinoharaet al.1969) simplifies the analysis of contaminant dispersion in estuaries. Attention is restricted to estuaries which are small in the sense that cross-sectional mixing is rapid and that the tidal elevation can be taken to be constant along the estuary. In agreement with the work of Fischer (1972a, b) it is found that the dominant mechanism for dispersion is the transverse shear and not the vertical shear. Results are presented to illustrate the dependence of the upstream penetration of salt upon the estuary geometry as well as upon the fresh-water discharge rate.

A diffusion process model for the optimal operation of a reservoir system

1975 ◽  
Vol 12 (04) ◽  
pp. 859-863
Author(s):  
Stanley R. Pliska
Keyword(s):  
Optimal Control ◽  
Diffusion Process ◽  
Process Model ◽  
Discharge Rate ◽  
Water Discharge ◽  
Optimal Operation ◽  
Water Levels ◽  
Control Problems ◽  
Release Rates ◽  
Controlled Diffusion

The water level in a reservoir is modelled as a controlled diffusion process on a compact interval of the real line. The problem is to control the water discharge rate so as to minimise the expected costs, which depend upon the histories of the water levels and release rates. The form of the optimal control is studied for two general classes of reservoir control problems.

Wastewater management strategies for the black sea coast of Turkey

1999 ◽  
Vol 39 (8) ◽  
pp. 169-176
Author(s):  
I. Ozturk ◽  
E. Yuksel ◽  
A. Tanik
Keyword(s):  
Black Sea ◽  
Management Strategy ◽  
Population Distribution ◽  
Management Strategies ◽  
The Black Sea ◽  
Wastewater Management ◽  
Black Sea Coast ◽  
The Cost ◽  
Solid Waste Landfills ◽  
Sea Coast

The Black Sea, surrounded by six riparian countries, is under the threat of severe pollution, giving rise to the need of taking precautions to protect it from further deterioration. In this paper, an effort putting forth a wastewater treatment and management strategy is outlined for the Black Sea coast of Turkey, including both the technical and financial aspects. The present situation of the coast in terms of land-based pollution and infrastructure is stated, followed by an applicable management strategy. The strategy developed for the coastal settlements involves various stagewise treatment schemes based on population distribution and densities along the coastline, and on the availability of land in a specified period of thirty years. Similar strategies are proposed for the control of pollution originating from industries, for those carried by rivers joining the sea, and for leachate of solid waste landfills. The cost estimations of various treatment schemes are also given in terms of population equivalents.

scholarly journals An Optimal Control Problem by a Hybrid System of Hyperbolic and Ordinary Differential Equations

Games ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 23
Author(s):  
Alexander Arguchintsev ◽  
Vasilisa Poplevko
Keyword(s):  
Optimal Control ◽  
Differential Equations ◽  
Optimal Control Problem ◽  
Control Problem ◽  
Ordinary Differential Equations ◽  
Hyperbolic Equations ◽  
Control Methods ◽  
The Right ◽  
The Cost ◽  
Optimal Control Methods

This paper deals with an optimal control problem for a linear system of first-order hyperbolic equations with a function on the right-hand side determined from controlled bilinear ordinary differential equations. These ordinary differential equations are linear with respect to state functions with controlled coefficients. Such problems arise in the simulation of some processes of chemical technology and population dynamics. Normally, general optimal control methods are used for these problems because of bilinear ordinary differential equations. In this paper, the problem is reduced to an optimal control problem for a system of ordinary differential equations. The reduction is based on non-classic exact increment formulas for the cost-functional. This treatment allows to use a number of efficient optimal control methods for the problem. An example illustrates the approach.

scholarly journals Prevalence, awareness, treatment, and control of dyslipidemia among diabetes mellitus patients and predictors of optimal dyslipidemia control: results from the Korea National Health and Nutrition Examination Survey

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Seung Jae Kim ◽  
Oh. Deog Kwon ◽  
Kyung-Soo Kim
Keyword(s):  
Diabetes Mellitus ◽  
Optimal Control ◽  
National Health ◽  
Age Groups ◽  
Density Lipoprotein ◽  
Nutrition Examination Survey ◽  
Cross Sectional ◽  
Health And Nutrition ◽  
Factors Influencing ◽  
And Control

Abstract Background This study aimed to investigate the prevalence, awareness, treatment, and control rates of dyslipidemia and identify the predictors of optimal control (low-density lipoprotein cholesterol < 100 mg/dL) among patients with diabetes mellitus (DM). Methods A cross-sectional study was conducted using the representative Korea National Health and Nutrition Examination Survey (2014–2018). Overall, 4311 patients with DM, aged ≥19 years, and without cardiovascular diseases were selected, and the prevalence, awareness, treatment, and control rates of dyslipidemia were calculated. Univariate and multivariate logistic regression analyses were conducted to evaluate the factors influencing the optimal control of dyslipidemia. Results Dyslipidemia was prevalent in 83.3% of patients with DM, but the awareness and treatment rates were 36.5 and 26.9%, respectively. The control rate among all patients with dyslipidemia was 18.8%, whereas it was 61.1% among those being treated. Prevalence and awareness rates were also significantly higher in women than in men. Dyslipidemia was most prevalent in those aged 19–39 years, but the rates of awareness, treatment, and control among all patients with dyslipidemia in this age group were significantly lower than those in other age groups. The predictors of optimal control were age ≥ 40 years [range 40–49 years: adjusted odds ratio (aOR) 3.73, 95% confidence interval (CI) 1.43–9.72; 50–59 years: aOR 6.25, 95% CI 2.50–15.65; 60–69 years: aOR 6.96, 95% CI 2.77–17.44; 70–79 years: aOR 9.21, 95% CI 3.58–23.74; and ≥ 80 years: aOR 4.43, 95% CI 1.60–12.27]; urban living (aOR 1.44, 95% CI 1.15–1.80); higher body mass index (aOR 1.27, 95% CI 1.13–1.42); lower glycated hemoglobin levels (aOR 0.71, 95% CI 0.67–0.76); hypertension (aOR 1.53, 95% CI 1.22–1.92); poorer self-rated health status (aOR 0.72, 95% CI 0.62–0.84); and receiving regular health check-ups (aOR 1.58, 95% CI 1.25–2.00). Conclusions Most patients with DM were diagnosed with dyslipidemia, but many were unaware of or untreated for their condition. Therefore, their control rate was suboptimal. Thus, by understanding factors influencing optimal control of dyslipidemia, physicians should make more effort to encourage patients to undergo treatment and thus, adequately control their dyslipidemia.

scholarly journals Dynamical Analysis and Optimal Control for a SEIR Model Based on Virus Mutation in WSNs

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 929
Author(s):  
Guiyun Liu ◽  
Jieyong Chen ◽  
Zhongwei Liang ◽  
Zhimin Peng ◽  
Junqiang Li
Keyword(s):  
Optimal Control ◽  
Rapid Development ◽  
Hamiltonian Function ◽  
Propagation Model ◽  
Dynamical Analysis ◽  
Optimal Control Strategy ◽  
Epidemic Dynamics ◽  
Optimization Control ◽  
The Cost ◽  
The Pontryagin Maximum Principle

With the rapid development of science and technology, the application of wireless sensor networks (WSNs) is more and more widely. It has been widely concerned by scholars. Viruses are one of the main threats to WSNs. In this paper, based on the principle of epidemic dynamics, we build a SEIR propagation model with the mutated virus in WSNs, where E nodes are infectious and cannot be repaired to S nodes or R nodes. Subsequently, the basic reproduction number R0, the local stability and global stability of the system are analyzed. The cost function and Hamiltonian function are constructed by taking the repair ratio of infected nodes and the repair ratio of mutated infected nodes as optimization control variables. Based on the Pontryagin maximum principle, an optimal control strategy is designed to effectively control the spread of the virus and minimize the total cost. The simulation results show that the model has a guiding significance to curb the spread of mutated virus in WSNs.

Evaluating the Outcomes of a Hospital-to-Community Model of Integrated Care for Dementia

2020 ◽  
pp. 1-6
Author(s):  
Ngoc Huong Lien Ha ◽  
Philip Yap Lin Kiat ◽  
Sean Olivia Nicholas ◽  
Ivana Chan ◽  
Shiou Liang Wee
Keyword(s):  
Cost Effectiveness ◽  
Integrated Care ◽  
Dementia Care ◽  
Behavioural Problems ◽  
Gdp Per Capita ◽  
Post Intervention ◽  
Cross Sectional ◽  
Life Years ◽  
Per Capita ◽  
The Cost

<b><i>Introduction:</i></b> Living with dementia is challenging for persons with dementia (PWDs) and their families. Although multi-component intervention, underscored by the ethos of person-centred care, has been shown to maintain quality of life (QOL) in PWDs and caregivers, a lack of service integration can hinder effectiveness. <b><i>Methods:</i></b> CARITAS, an integrated care initiative provided through a hospital-community care partnership, endeavours to provide person-centred dementia care through ambulatory clinic consults, case management, patient and caregiver engagement, and support. We evaluated CARITAS’ clinical outcomes and cost-effectiveness with a naturalistic cross-sectional within-subject design. We assessed patients’ function, QOL, and behavioural problems post-intervention. We estimated CARITAS’ cost-effectiveness from a patient’s perspective, benchmarking it against other dementia treatments and Singapore’s Gross Domestic Product (GDP) per capita. <b><i>Results:</i></b> CARITAS care significantly improved health utility (<i>p</i> &#x3c; 0.001), reduced caregiver burden (<i>p</i> &#x3c; 0.001), and improved PWDs’ behavioural problems (<i>p</i> &#x3c; 0.001) related to “memory” (<i>p</i> &#x3c; 0.001), “disruption” (<i>p</i> = 0.017), and “depression” (<i>p</i> &#x3c; 0.001). CARITAS’ benefits (<i>d</i><sub>RMBPC</sub> = 0.357, <i>d</i><sub>EQ5D index</sub> = 0.328, <i>d</i><sub>ZBI</sub> = 0.361) were comparable to those of other pharmacological and non-pharmacological interventions for dementia. CARITAS costs SG$133,056.69 per quality-adjusted life years gain, yielding an incremental cost-effectiveness ratio of 1.31 and 1.49 against the cost of donepezil in patients with mild Alz­heimer’s disease and Singapore’s GDP per capita in 2019, respectively, falling within the cost-effectiveness threshold of 1.0–3.0. <b><i>Discussion:</i></b> CARITAS integrated dementia care is a cost-effective intervention that showed promising outcomes for PWDs and their caregivers.

scholarly journals Cost-Effectiveness of Colorectal Cancer Genetic Testing

2021 ◽  
Vol 18 (16) ◽  
pp. 8330
Author(s):  
Abdul Rahman Ramdzan ◽  
Mohd Rizal Abdul Manaf ◽  
Azimatun Noor Aizuddin ◽  
Zarina A. Latiff ◽  
Keng Wee Teik ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Genetic Testing ◽  
Cost Effectiveness ◽  
Cancer Survival ◽  
Screening Method ◽  
Targeted Prevention ◽  
Activity Based Costing ◽  
Cross Sectional ◽  
Increased Risk ◽  
The Cost

Colorectal cancer (CRC) remains the second leading cause of cancer-related deaths worldwide. Approximately 3–5% of CRCs are associated with hereditary cancer syndromes. Individuals who harbor germline mutations are at an increased risk of developing early onset CRC, as well as extracolonic tumors. Genetic testing can identify genes that cause these syndromes. Early detection could facilitate the initiation of targeted prevention strategies and surveillance for CRC patients and their families. The aim of this study was to determine the cost-effectiveness of CRC genetic testing. We utilized a cross-sectional design to determine the cost-effectiveness of CRC genetic testing as compared to the usual screening method (iFOBT) from the provider’s perspective. Data on costs and health-related quality of life (HRQoL) of 200 CRC patients from three specialist general hospitals were collected. A mixed-methods approach of activity-based costing, top-down costing, and extracted information from a clinical pathway was used to estimate provider costs. Patients and family members’ HRQoL were measured using the EQ-5D-5L questionnaire. Data from the Malaysian Study on Cancer Survival (MySCan) were used to calculate patient survival. Cost-effectiveness was measured as cost per life-year (LY) and cost per quality-adjusted life-year (QALY). The provider cost for CRC genetic testing was high as compared to that for the current screening method. The current practice for screening is cost-saving as compared to genetic testing. Using a 10-year survival analysis, the estimated number of LYs gained for CRC patients through genetic testing was 0.92 years, and the number of QALYs gained was 1.53 years. The cost per LY gained and cost per QALY gained were calculated. The incremental cost-effectiveness ratio (ICER) showed that genetic testing dominates iFOBT testing. CRC genetic testing is cost-effective and could be considered as routine CRC screening for clinical practice.

scholarly journals Cross-sectional study of prevalence and risk factors, and a cost-effectiveness evaluation of screening and preventive treatment strategies for latent tuberculosis among migrants in Singapore

BMJ Open ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. e050629
Author(s):  
Vanessa W Lim ◽  
Hwee Lin Wee ◽  
Phoebe Lee ◽  
Yijun Lin ◽  
Yi Roe Tan ◽  
...  
Keyword(s):  
Risk Factors ◽  
Cost Effectiveness ◽  
Length Of Stay ◽  
Latent Tuberculosis ◽  
Cross Sectional Study ◽  
Secondary Outcome ◽  
Sectional Study ◽  
Cross Sectional ◽  
Ltbi Prevalence ◽  
The Cost

ObjectivesWHO recommends that low burden countries consider systematic screening and treatment of latent tuberculosis infection (LTBI) in migrants from high incidence countries. We aimed to determine LTBI prevalence and risk factors and evaluate cost-effectiveness of screening and treating LTBI in migrants to Singapore from a government payer perspective.DesignCross-sectional study and cost-effectiveness analysis.SettingMigrants in Singapore.Participants3618 migrants who were between 20 and 50 years old, have not worked in Singapore previously and stayed in Singapore for less than a year were recruited.Primary and secondary outcome measuresCosts, quality-adjusted life-years (QALYs), threshold length of stay, incremental cost-effectiveness ratios (ICERs), cost per active TB case averted.ResultsOf 3584 migrants surveyed, 20.4% had positive interferon-gamma release assay (IGRA) results, with the highest positivity in Filipinos (33.2%). Higher LTBI prevalence was significantly associated with age, marital status and past TB exposure. The cost-effectiveness model projected an ICER of S$57 116 per QALY and S$12 422 per active TB case averted for screening and treating LTBI with 3 months once weekly isoniazid and rifapentine combination regimen treatment compared with no screening over a 50-year time horizon. ICER was most sensitive to the cohort’s length of stay in Singapore, yearly disease progression rates from LTBI to active TB, followed by the cost of IGRA testing.ConclusionsFor LTBI screening and treatment of migrants to be cost-effective, migrants from high burden countries would have to stay in Singapore for ~50 years. Risk-stratified approaches based on projected length of stay and country of origin and/or age group can be considered.

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