Coupled ethical-epistemic analysis of public health research and practice: categorizing variables to improve population health and equity

The categorization of variables can stigmatize populations, which is ethically problematic and threatens the central purpose of public health: to improve population health and reduce health inequities. How social variables (e.g., behavioral risks for HIV) are categorized can reinforce stigma and cause unintended harms to the populations practitioners and researchers strive to serve.<p></p> Although debates about the validity or ethical consequences of epidemiological variables are familiar for specific variables (e.g., ethnicity), these issues apply more widely.<p></p> We argue that these tensions and debates regarding epidemiological variables should be analyzed simultaneously as ethical and epistemic challenges. We describe a framework derived from the philosophy of science that may be usefully applied to public health, and we illustrate its application.<p></p&gt

Urban-rural inequalities in suicide among elderly people in China: a systematic review and meta-analysis

Background: China has an unusual pattern of suicides, with overall suicide rates in rural areas higher than urban areas. While suicide rates have decreased dramatically, older people increasingly contribute to the overall burden of suicide. However, it is unclear if elderly people within rural areas experience greater suicide risk than those in urban areas. We aimed to systematically review the incidence of suicide in rural and urban China among the elderly (aged over 60 years), with a view to describing the difference in rates between rural and urban areas and trends over time. Methods: Chinese and English language articles were searched for using four databases: EMBASE (Ovid), MEDLINE (Ovid), PsycINFO (EBSCOhost) and CNKI (in Chinese). Articles describing completed suicide among elderly people in both rural and urban areas in mainland China were included. The adapted Newcastle-Ottawa Scale (NOS) was used to assess risk of bias. One reviewer (ML) assessed eligibility, performed data extraction and assessed risk of bias, with areas of uncertainty discussed with the second reviewer (SVK). Random effects meta-analysis was conducted. Suicide methods in different areas were narratively summarised. Results: Out of a total 3065 hits, 24 articles were included and seven contributed data to meta-analysis. The sample size of included studies ranged from 895 to 323.8 million. The suicide rate in the general population of China has decreased in recent decades over previous urban and rural areas. Suicide rates amongst the elderly in rural areas are higher than those in urban areas (OR = 3.35; 95% CI of 2.48 to 4.51; I2 = 99.6%), but the latter have increased in recent years. Insecticide poisoning and hanging are the most common suicide methods in rural and urban areas respectively. Suicide rates for these two methods increase with age, being especially high in elderly people. Conclusions: The pattern of suicide in China has changed in recent years following urbanisation and aging. Differences in suicide rates amongst the elderly exist between rural and urban areas. Addressing the high suicide rate amongst the elderly in rural China requires a policy response, such as considering measures to restrict access to poisons

Robust Control of Input Limited Smart Structural Systems

Integration of controllers with smart structural systems require the controllers to consume less power and to be small in hardware size. These requirements pose as limits on the control input and the order of the controllers. Use of reduced order model of the plant in the controller design can cause spill over problems in the closed-loop system due to possible excitation of the unmodeled dynamics. In this paper, we present a method to design output feedback robust controllers for smart structures in the presence of control input limits considering unmodeled dynamics as additive uncertainty in the design. The performance requirements for the design are specified as regional pole placement constraints on the closed-loop poles. The controller design problem requires the maximization of damping ratio in the presence of additive uncertainty and control input limits. The resulting optimization problem for the controller design is formulated as a generalized eigenvalue problem involving linear matrix inequality (LMI) constraints. The proposed controller is designed and implemented on a multiinput-multioutput 3-mass smart structural test article. The tradeoffs involved in the controller design are analyzed and the performance and robustness specifications are verified experimentall

Reduced Order Modeling Methods For Turret-gun System

Reduced-order modeling techniques are used to design lower order robust controllers for a turret-gun system. The balance-truncation, Routh approximation, and L. Litz\u27s (1980) modal techniques are used to derive the models. A critical comparison of the time and frequency response characteristics of the original and reduced order models is made. The spillover problem associated with a reduced-order model is investigated

Linear State Variable Dynamic Model And Estimator Design For Allison 1406 Gas Turbine Engine

This paper describes a procedure for developing a State Variable Model for the Allison T406 gas turbine engine. This linear model is useful for designing controllers using modern control techniques. The engine and V-22 rotor system is modeled around an operating point by using four state variables and one input variable. For a given power setting, it is observed that two linear models are sufficient to represent the engine dynamics over the entire flight envelope. A relationship between surge margin and the state variables is also developed. It is demonstrated that these linear models are useful in designing an estimator for accommodating hard sensor failures

Project Management Concepts

This chapter covers fundamentals of project management. It introduces project management concepts and provides a system view of project management plan and processes with which they are implemented. The knowledge areas include scope, time, cost, quality, and risk. The chapter will also emphasize on the interrelated nature of these knowledge areas. In addition to introducing these knowledge areas, the chapter will attempt to develop an understanding of these concepts and the important role of project teams in managing projects successfully. This chapter will also discuss similarities and differences between the plan-driven and change-driven (Agile) project methods

Robust Control Of Flexible Structures Using Multiple Shape Memory Alloy Actuators

The design and implementation of control strategies for large, flexible smart structures presents challenging problems. To demonstrate the capabilities of shape-memory-alloy actuators, we have designed and fabricated a three-mass test article with multiple shape-memory-alloy (NiTiNOL) actuators. The force and moment actuators were implemented on the structure to examine the effects of control structure interaction and to increase actuation force. These SMA actuators exhibit nonlinear effects due to dead band and saturation. The first step in the modeling process was the experimental determination of the transfer function matrix derived from frequency response data. A minimal state space representation was determined based on this transfer function matrix. Finally in order to reduce the order of the controller, a reduced order state space model was derived from the minimal state space representation. The simplified analytical models are compared with models developed by structural identification techniques based on vibration test data. From the reduced order model, a controller was designed to dampen vibrations in the test bed. To minimize the effects of uncertainties on the closed-loop system performance of smart structures, a LQG/LTR control methodology has been utilized. An initial standard LQG/LTR controller was designed; however, this controller could not achieve the desired performance robustness due to saturation effects. Therefore, a modified LQG/LTR design methodology was implemented to accommodate for the limited control force provided by the actuators. The closed-loop system response of the multiple input-multiple output (MIMO) test article with robustness verification has been experimentally obtained and presented in the paper. The modified LQG/LTR controller demonstrated performance and stability robustness to both sensor noise and parameter variations

Use of fly ash admixed concrete for pavement construction

The portland cement used for construction of rigid pavements is an energy intensive material and hence efforts are being made to find substitute materials for partial replacement of cement in concrete, and conserve energy. On the other hand, utilisation of coal for generation of power is increasing rapidly. This has resulted in production of large quantities of fly ash from coal burning power plants. Fly ash from thermal power plants can be used as an admixture to concrete for saving cement as well as to provide solutions for its disposal problems. Use of fly ash in concrete would be an environmentally friendly way of utilising a waste material like fly ash. Currently fly ash finds application in road pavement structure,mainly for sub-base /base course and embankment. Fly ash admixed concrete can be a very good material for construction of pavement. It is generally designed as a partial replacement of cement or aggregate or both. This paper describes the different methods of using fly ash in concrete as a paving material, advantages gained by using fly ash in concrete and mechanism of durability increase in fly ash admixed concrete. The experiences of CRRI for using fly ash admixed concrete are also highlighted