An Upper-Bound Control Approach for Cost-Effective Privacy Protection of Intermediate Dataset Storage in Cloud

2011 ◽  
Author(s):  
Xuyun Zhang ◽  
Chang Liu ◽  
Jinjun Chen ◽  
Wanchun Dou
Keyword(s):  
Upper Bound ◽  
Privacy Protection ◽  
Cost Effective ◽  
Control Approach ◽  
Bound Control

Energy-to-peak induced norm upper bound control approach for collocated structural systems

2007 ◽  
Author(s):  
Mona Meisami-azad ◽  
Javad Mohammadpour ◽  
Karolos M. Grigoriadis
Keyword(s):  
Upper Bound ◽  
Structural Systems ◽  
Control Approach ◽  
Bound Control

US Financial Debt Crisis: A Stochastic Optimal Control Approach

2011 ◽  
Vol 62 (3) ◽  
Author(s):  
Jerome L. Stein
Keyword(s):  
Optimal Control ◽  
Interest Rate ◽  
Financial Crisis ◽  
Upper Bound ◽  
Stochastic Optimal Control ◽  
Debt Crisis ◽  
Capital Gain ◽  
Empirical Measure ◽  
Net Worth ◽  
Control Approach

SummaryThe financial crisis was precipitated by the mortgage crisis. A whole structure of financial derivatives was based upon the ultimate debtors, the mortgagors. Insofar as the mortgagors were unable to service their debts, the values of the derivatives fell. The financial intermediaries whose assets and liabilities were based upon the value of derivatives were very highly leveraged. Changes in the values of their net worth were large multiples of changes in asset values. A cascade was precipitated by the mortgage defaults. In this manner, the mortgage debt crisis turned into a financial crisis. The crucial variable is the optimal debt of the real estate sector, which depends upon the capital gain and the interest rate. I apply the Stochastic Optimal Control (SOC) analysis to derive the optimal debt. Two models of the stochastic process on the capital gain and interest rate are presented. Each implies a different value of the optimal debt/net worth. I derive an upper bound of the optimal debt ratio, based upon the alternative models. An empirical measure of the excess debt: actual less the upper bound of the optimal ratio, is shown to be an early warning signal (EWS) of the debt crisis.

Cost Effective Skyhook Control for Vibration Isolation Systems

2005 ◽  
Author(s):  
Xubin Song
Keyword(s):  
Vibration Isolation ◽  
Control Policy ◽  
Cost Effective ◽  
Relative Displacement ◽  
Semiactive Control ◽  
Mass System ◽  
Control Approach ◽  
Car Suspension ◽  
Ride Control ◽  
Isolation Systems

Traditionally a skyhook control, widely applied to vibration control, requires two sensors to measure sprung mass acceleration and relative displacement, respectively. For the implementation, these two measurement signals are converted into velocities and then the damping control signal is decided and sent to controllable HH/SS dampers. In this paper, a one sensor based skyhook control policy is developed. The proposed control policy just needs one measurement signal, sprung mass acceleration, to estimate these two velocities for semiactive control. The new strategy is explained through a typical spring-mass system of a quarter-car model. But the effectiveness of the new control approach for vibration isolation is validated with ride control through simulation study of a 7-DOF full car suspension system with application of magneto-rheological (MR) dampers.

scholarly journals Estimation of the cost-effective threshold of a quality-adjusted life year in China based on the value of statistical life

2021 ◽  
Author(s):  
Dan Cai ◽  
Si Shi ◽  
Shan Jiang ◽  
Lei Si ◽  
Jing Wu ◽  
...  
Keyword(s):  
Lower Bound ◽  
Upper Bound ◽  
Cost Effective ◽  
Quality Adjusted Life Year ◽  
Gdp Per Capita ◽  
Economic Evaluations ◽  
Value Of Statistical Life ◽  
Statistical Life ◽  
Per Capita ◽  
Quality Adjusted Life

AbstractCost-effective threshold (CET) is essential for health technology assessment and decision-making based on health economic evaluations. Recently, it has been argued that the commonly used once and three times of gross domestic product (GDP) per capita CETs of a quality-adjusted life year (QALY) are not necessarily empirically supported in all countries. Therefore, we aimed to estimate the CET of a QALY as times of GDP per capita in China, of which the reimbursement coverage decisions are increasingly engaging economic evaluations. Estimates on the value of statistical life (VSL) in China were identified from several studies in the literature and converted to times of GDP per capita, the weighted average of which was used for subsequent calculation. By pooling data on population mortality, health utility, and age distribution, we estimated the value of a statistical QALY (VSQ) from VSL using an established mathematical process, which represented the theoretical upper bound of CET. The corresponding point estimate and theoretical lower bound were obtained using their numerical relationships with the upper bound. Scenarios analyses were also conducted. The estimated CET, its upper bound, and its lower bound were 1.45, 2.90, and 1.16 times of GDP per capita in China, respectively. In different scenarios, the estimated CET varied but was greater than once GDP per capita in most cases. As such, the CET of a QALY in China is close to 1.5 times of GDP per capita, which should be benchmarked for future ICER-based coverage decisions.

A Game Theory Approach for Estimating Reliability of Crowdsourced Relevance Assessments

2022 ◽  
Vol 40 (3) ◽  
pp. 1-29
Author(s):  
Yashar Moshfeghi ◽  
Alvaro Francisco Huertas-Rosero
Keyword(s):  
Upper Bound ◽  
Cost Effective ◽  
Majority Voting ◽  
Task Completion ◽  
Theory Approach ◽  
Weighted Majority ◽  
Use Of Time ◽  
Optimal Function ◽  
Closing The Gap ◽  
Source Of Information

In this article, we propose an approach to improve quality in crowdsourcing (CS) tasks using Task Completion Time (TCT) as a source of information about the reliability of workers in a game-theoretical competitive scenario. Our approach is based on the hypothesis that some workers are more risk-inclined and tend to gamble with their use of time when put to compete with other workers. This hypothesis is supported by our previous simulation study. We test our approach with 35 topics from experiments on the TREC-8 collection being assessed as relevant or non-relevant by crowdsourced workers both in a competitive (referred to as “Game”) and non-competitive (referred to as “Base”) scenario. We find that competition changes the distributions of TCT, making them sensitive to the quality (i.e., wrong or right) and outcome (i.e., relevant or non-relevant) of the assessments. We also test an optimal function of TCT as weights in a weighted majority voting scheme. From probabilistic considerations, we derive a theoretical upper bound for the weighted majority performance of cohorts of 2, 3, 4, and 5 workers, which we use as a criterion to evaluate the performance of our weighting scheme. We find our approach achieves a remarkable performance, significantly closing the gap between the accuracy of the obtained relevance judgements and the upper bound. Since our approach takes advantage of TCT, which is an available quantity in any CS tasks, we believe it is cost-effective and, therefore, can be applied for quality assurance in crowdsourcing for micro-tasks.

scholarly journals Seeking Best-Balanced Patch-Injecting Strategies through Optimal Control Approach

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Kaifan Huang ◽  
Pengdeng Li ◽  
Lu-Xing Yang ◽  
Xiaofan Yang ◽  
Yuan Yan Tang
Keyword(s):  
Optimal Control ◽  
Optimal Control Problem ◽  
Control Problem ◽  
Negative Impact ◽  
Cost Effective ◽  
Control Approach ◽  
Novel Virus ◽  
Optimality Systems ◽  
Objective Functional ◽  
Optimal Control Approach

To restrain escalating computer viruses, new virus patches must be constantly injected into networks. In this scenario, the patch-developing cost should be balanced against the negative impact of virus. This article focuses on seeking best-balanced patch-injecting strategies. First, based on a novel virus-patch interactive model, the original problem is reduced to an optimal control problem, in which (a) each admissible control stands for a feasible patch-injecting strategy and (b) the objective functional measures the balance of a feasible patch-injecting strategy. Second, the solvability of the optimal control problem is proved, and the optimality system for solving the problem is derived. Next, a few best-balanced patch-injecting strategies are presented by solving the corresponding optimality systems. Finally, the effects of some factors on the best balance of a patch-injecting strategy are examined. Our results will be helpful in defending against virus attacks in a cost-effective way.

Benefits and feasibility of local elimination of possum populations

2006 ◽  
Vol 33 (7) ◽  
pp. 605 ◽  
Author(s):  
D. R. Morgan ◽  
G. Nugent ◽  
B. Warburton
Keyword(s):  
Control Strategies ◽  
Cost Effective ◽  
Population Characteristics ◽  
Effective Control ◽  
Brushtail Possum ◽  
Control Approach ◽  
Initial Cost ◽  
Regulatory Status ◽  
The Cost

Introduction of the brushtail possum (Trichosurus vulpecula) to New Zealand has resulted in serious ecological and economic impacts and considerable control efforts. Recovery of possum populations after control occurs through immigration from adjacent areas and breeding of survivors and immigrants. If complete local elimination can be achieved, the recovery of populations will depend solely on immigration and therefore should be substantially slowed (particularly in very large areas). To compare the cost-effectiveness of four control strategies over the long term (60 years), we constructed a deterministic bioeconomic model based on 23 variables describing population characteristics, sizes of the sink (i.e. area controlled) and source (of reinfestation) areas, and costs. Sensitivity analysis showed that the most influential variables related primarily to cost and effectiveness of control, whereas factors describing immigration after control had relatively little influence. When the most influential variables were varied, the model predicted that local elimination of possums followed by ‘perimeter’ control is likely to be a more cost-effective control strategy under most scenarios than the current ‘knockdown-then-maintenance-control’ approach. Possum-control technology and its application have improved greatly in the last three decades such that it now appears that local elimination is, technically, a realistic goal, and is possibly already being achieved occasionally. Constraining factors include unreliable monitoring/detection at ultralow densities, inappropriate selection and use of control options, lack of incentive under the present contracting system, initial cost, contracting capacity, and the future regulatory status of poisons. However, these difficulties can be overcome, facilitating the adoption of long-term local elimination strategies that are better suited to managing possum populations in perpetuity.

Integration of equalisation tanks within control strategies for anaerobic reactors. Validation based on ADM1 simulations.

2008 ◽  
Vol 57 (5) ◽  
pp. 747-752 ◽  
Author(s):  
J. Alferes ◽  
J. L. García-Heras ◽  
E. Roca ◽  
C. García ◽  
I. Irizar
Keyword(s):  
Biogas Production ◽  
Control Strategies ◽  
Cost Effective ◽  
Anaerobic Digesters ◽  
Control Approach ◽  
Anaerobic Reactors ◽  
On Line ◽  
Hybrid Configuration ◽  
Real Time Information

The combination of equalisation tanks and anaerobic digesters represents a typical design scenario within the treatment of industrial wastewaters. In this context, if the hydraulic capacity of the equalisation tanks is effectively handled, significant improvements in the performance of anaerobic digesters can be achieved in terms of process stability and biogas production. This paper presents a rule-based control strategy for anaerobic reactors with the objective of maximising in the long-term the net production of biogas. The control algorithm combines real-time information about the state of the anaerobic digester with on-line measurements about the wastewater volume of the equalisation tank in order to set permanently the appropriate production of biogas. Such a strategy guarantees a continuous influent flow so that emptying and overflowing episodes in the equalisation tank can be prevented. Aiming at a further full-scale implementation, only reliable and cost-effective on-line instrumentation has been considered within the control architecture. The performance of the proposed control approach has been validated for an anaerobic hybrid configuration (AHR) by simulation using the IWA ADM1 model.

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