Self-reported health-related quality of life (HRQoL) and factors affecting HRQoL among individuals with health insurance in Iran

Ali Kazemi Karyani,Arash Rashidian,Sarar Emamgholipour Sefiddashti,Ali Akbari Sari 한국역학회 2016 Epidemiology and Health Vol.38 No.-

OBJECTIVES: The aim of this study was to measure the health-related quality of life (HRQoL) and to evaluate the factors affecting HRQoL in individuals with health insurance in Tehran, Iran. METHODS: A cross-sectional analytical study was conducted using the 3-level EuroQol 5-dimensions (EQ-5D) questionnaire. In order to estimate the determinants of HRQoL, information about participants’ demographic, socioeconomic, and health status was gathered. The cluster sampling technique was used to collect data from May to June, 2016. The chi-square test and weighted least squares method were employed for data analysis. Data were analyzed using Stata version 11.0. RESULTS: A total of 600 Iranians with insurance completed the study, of whom 327 (54.5%) were male and 273 (45.5%) were female. The mean age of the participants was 41.48 years (standard deviation [SD], 14.60 years). Meanwhile, the mean duration of education was 12.36 years (SD, 4.68 years). The mean EQ-5D score was 0.74 (SD, 0.16). The most common health problems in the participants were anxiety/depression (42.3%), followed by pain/discomfort (39.2%). Sex, age, years of schooling, income, chronic disease, and body mass index had a significant effect on HRQoL (p<0.05). Healthy insured individuals, on average, had a HRQoL score 0.119 higher than that of people with a chronic disease, all else being equal (p<0.001). CONCLUSIONS: Among all determinants of HRQoL, chronic disease was found to be the highest priority for interventions to improve the health status of Iranians with insurance. This finding can help policymakers and health insurance organizations improve their planning to promote the HRQoL of individuals with insurance and society as a whole in Iran.

H_∞ filter design for offshore platforms via sampled-data measurements

Kazemy, Ali Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.21 No.2

This paper focuses on the $H_{\infty}$ filter design problem for offshore steel jacket platforms. Its objective is to design a full-order state observer for offshore platforms in presence of unknown disturbances. To make the method more practical, it is assumed that the measured variables are available at discrete-time instants with time-varying sampling time intervals. By modelling the sampling intervals as a bounded time-varying delay, the estimation error system is expressed as a time-delay system. As a result, the addressed problem can be transformed to the problem of stability of dynamic error between the system and the state estimator. Then, based on the Lyapunov-Krasovskii Functional (LKF), a stability criterion is obtained in the form of Linear Matrix Inequalities (LMIs). According to the stability criterion, a sufficient condition on designing the state estimator gain is obtained. In the end, the proposed method is applied to an offshore platform to show its effectiveness.

Consecutive Synchronization of a Delayed Complex Dynamical Network via Distributed Adaptive Control Approach

Ali Kazemy,Jinde Cao 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.6

In this paper, a consecutive synchronization scheme is investigated to synchronize the nodes of a delayed complex dynamical network with an isolated node via an adaptive control approach. The specific feature of this scheme consists in the structure of the communication links: a communication connection is required between the isolated node and one selected node in the network, and further communication links exist between any node and one neighbor node. In this way, all nodes are connected together like a chain. Based on Lyapunov-Krasovskii theory, some conditions are obtained in the form of linear matrix inequalities to guarantee the consecutive synchronization by the designed distributed adaptive control. To make this synchronization scheme more practical, no constraints have been considered for coupling connection matrix such as being symmetric or zero row sum. Finally, a numerical example is presented to demonstrate the effectiveness of the proposed method.

H filter design for offshore platforms via sampled-data measurements

Ali Kazemy 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.21 No.2

This paper focuses on the H filter design problem for offshore steel jacket platforms. Its objective is to design a full-order state observer for offshore platforms in presence of unknown disturbances. To make the method more practical, it is assumed that the measured variables are available at discrete-time instants with time-varying sampling time intervals. By modelling the sampling intervals as a bounded time-varying delay, the estimation error system is expressed as a time-delay system. As a result, the addressed problem can be transformed to the problem of stability of dynamic error between the system and the state estimator. Then, based on the Lyapunov-Krasovskii Functional (LKF), a stability criterion is obtained in the form of Linear Matrix Inequalities (LMIs). According to the stability criterion, a sufficient condition on designing the state estimator gain is obtained. In the end, the proposed method is applied to an offshore platform to show its effectiveness.

Structural instability of carbon nanotubes embedded in viscoelastic medium and subjected to distributed tangential load

Mohammad Ali Kazemi-Lari,Esmaeal Ghavanloo,S. Ahmad Fazelzadeh 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.7

In this paper, the nonlocal Euler-Bernoulli beam model is used to predict the static and dynamic structural instability of carbon nanotubes (CNTs) subjected to a distributed tangential compressive load. The CNT is considered to be embedded in a Kelvin-Voigt viscoelastic medium. Equation of motion and boundary conditions are obtained using the extended Hamilton’s principle and the extended Galerkin’s method is applied in order to transform the resulting equations into a general eigenvalue problem. The derived equations are validated by comparing the results achieved from the new derivations with existing solutions in literature. Effects of several experimentally interesting boundary conditions are considered on the stability characteristics of the CNT. Moreover, the influences of small scale parameter and material properties of the surrounding viscoelastic medium on the stability boundaries are examined.

SIMULATING DEFLECTION AND DETERMINING STABLE LENGTH OF FREESTANDING CARBON NANOTUBE PROBE/SENSOR IN THE VICINITY OF GRAPHENE LAYERS USING A NANOSCALE CONTINUUM MODEL

ALI KOOCHI,ASIEHSADAT KAZEMI,MOHAMADREZA ABADYAN 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2011 NANO Vol.6 No.5

Herein, the deflection and instability of a freestanding carbon nanotube (CNT) probe/sensor in the vicinity of the graphene layers are investigated. A nanoscale continuum model is employed to obtain nonlinear constitutive equation of freestanding CNT. The van der Waals attraction is computed from the simplified Lennard-Jones potential for two common engineering cases including large and small number of graphene layers. Four approaches, i.e., approximated function, homotopy perturbation method, lumped parameter model and numerical analysis, are employed to solve the governing equation of CNT. The intermolecular force-induced deflection, minimum initial gap and stable length of freestanding CNT are determined. The analytical results agree well with the numerical solutions.

Road profile estimation using wavelet neural network and 7-DOF vehicle dynamic systems

Ali Solhmirzaei,Shahram Azadi,Reza Kazemi 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.10

Road roughness is a broad term that incorporates everything from potholes and cracks to the random deviations that exist in a profile. To build a roughness index, road irregularities need to be measured first. Existing methods of gauging the roughness are based either on visual inspections or using one of a limited number of instrumented vehicles that can take physical measurements of the road irregularities. This paper more specifically focuses on the estimation of a road profile (i.e., along the "wheel track"). This paper proposes a solution to the road profile estimation using a wavelet neural network (WNN) approach. The method incorporates a WNN which is trained using the data obtained from a 7-DOF vehicle dynamic model in the MATLAB Simulink software to approximate road profiles via the accelerations picked up from the vehicle. In this paper, a novel WNN, multi-input and multi-output feed forward wavelet neural network is constructed. In the hidden layer, wavelet basis functions are used as activate function instead of the sigmoid function of feed forward network. The training formulas based on BP algorithm are mathematically derived and a training algorithm is presented. The study investigates the estimation capability of wavelet neural networks through comparison between some estimated and real road profiles in the form of actual road roughness.

Weakly stochastic Runge-Kutta method with order 2

Ali R. Soheili,Zahra Kazemi 한국전산응용수학회 2008 Journal of applied mathematics & informatics Vol.26 No.1

Many deterministic systems are described by Ordinary differential equations and can often be improved by including stochastic effects, but numerical methods for solving stochastic differential equations(SDEs) are required, and work in this area is far less advanced than for deterministic differential equations. In this paper,first we follow [7] to describe Runge-Kutta methods with order 2 from Taylor approximations in the weak sense and present two well known Runge-Kutta methods, RK2-TO and RK2-PL. Then we obtain a new 3-stage explicit Runge-Kutta with order 2 in weak sense and compare the numerical results among these three methods.

Exact stability of a platoon of vehicles by considering time delay and lag

Ali Ghasemi,Reza Kazemi,Shahram Azadi 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.2

The problem of controlling a string of vehicles moving in one dimension is considered so that they all follow a lead vehicle with constanttime headway spacing between successive vehicles. Due to realistic design and execution, the negative effect of the tracking lagparameter and time delay is taken into account. By applying an acceleration feedforward, the distance error of each vehicle will be independentof the behavior of other vehicles. As a result, the vehicle is better able to track a desired trajectory, which improves the stringstability. Cluster treatment of characteristic roots (CTCR) paradigm is utilized to reveal the stabilizing parametric regions in the domainof the time delay to render the stability of closed loop system. The string stability analysis is performed to evaluate the disturbance attenuation. Finally, an example of multiple vehicle platoon control is presented, which demonstrates the effectiveness of the proposedmethod.

Analysis of fluid flow and heat transfer of nanofluid inside triangular enclosure equipped with rotational obstacle

Ali Akbar Abbasian Arani,Mehrdad Kazemi 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.10

Fluid flow, heat transfer and entropy generation inside triangular enclosure equipped with rotational obstacle filled with nanofluid were analyzed numerically by finite difference method and SIMPELR algorithm. Five cases for apex angle, swirling circle radios and spine velocity, swirling circle radios and positions and five cases for wavy wall domain and amplitude were simulated. Although α = 20 has higher average Nusslet number, α = 30 has chosen as optimum apex angle due to meet to geometry problem in next step of optimization process. Optimum wavy wall according to average Nusselt number is constructed with A = 0.05 and D = 1.45π. Radius equal to 0.1 and position equal to 3 has been obtained as optimum geometry between multiple choices. Maximum Nusselt number and entropy generation deal with blades shapes and followed by bricks, platelets and cylinder shapes for nanoparticle volume fraction of between 0.5 and 5 and Rayleigh numbers from 10 3 and 10 6 .