scholarly journals Fuzzy Modeling and Control of HIV Infection

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Hassan Zarei ◽  
Ali Vahidian Kamyad ◽  
Ali Akbar Heydari
Keyword(s):  
Viral Load ◽  
Fuzzy Control ◽  
Hiv Infection ◽  
Immune Cells ◽  
Control Function ◽  
Drug Dosage ◽  
Modeling And Control ◽  
Proposed Model ◽  
Linear Fuzzy Differential Equations ◽  
And Control

The present study proposes a fuzzy mathematical model of HIV infection consisting of a linear fuzzy differential equations (FDEs) system describing the ambiguous immune cells level and the viral load which are due to the intrinsic fuzziness of the immune system's strength in HIV-infected patients. The immune cells in question are considered CD4+ T-cells and cytotoxic T-lymphocytes (CTLs). The dynamic behavior of the immune cells level and the viral load within the three groups of patients with weak, moderate, and strong immune systems are analyzed and compared. Moreover, the approximate explicit solutions of the proposed model are derived using a fitting-based method. In particular, a fuzzy control function indicating the drug dosage is incorporated into the proposed model and a fuzzy optimal control problem (FOCP) minimizing both the viral load and the drug costs is constructed. An optimality condition is achieved as a fuzzy boundary value problem (FBVP). In addition, the optimal fuzzy control function is completely characterized and a numerical solution for the optimality system is computed.

scholarly journals Analysis of Hysteresis-Free Creep of the Stack Piezoelectric Actuator

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Xueliang Zhao ◽  
Chengjin Zhang ◽  
Hongbo Liu ◽  
Guilin Zhang ◽  
Kang Li
Keyword(s):  
Fixed Point ◽  
Piezoelectric Actuator ◽  
High Speed ◽  
Creep Model ◽  
Modeling And Control ◽  
Creep Effect ◽  
Proposed Model ◽  
Series Of Experiments ◽  
Creep Models ◽  
And Control

A modified log-type creep model without hysteresis of the stack piezoelectric actuator is presented. For high-speed micro-/nanopositioning system, the time scale should be less than one second for creep modeling and control in the stack piezoelectric actuator. But creep effect was studied in the frame of minutes in previous works. Meanwhile, parameters of the classical creep models are hard to be determined. By the proposed model, the hysteresis and the creep effect can be separated. A series of experiments have been performed, where different staircase voltages have been applied to the actuator. There are two clear rules to follow in small duration and different heights to determine parameters. Firstly,L0starts from fixed point either in ascending stage or in descending stage and rotates clockwise. Secondly,γconverges to a small vicinity of a constant when the duration is small enough.

Fuzzy Control of a Pneumatic Muscle Driven Parallel Robot for Ankle Rehabilitation

2009 ◽  
Author(s):  
Prashant K. Jamwal ◽  
Shane Xie ◽  
Jack Farrant
Keyword(s):  
Fuzzy Control ◽  
Degrees Of Freedom ◽  
Fuzzy Controller ◽  
Parallel Robot ◽  
Modeling And Control ◽  
Pneumatic Muscle ◽  
Linear Behavior ◽  
Improved Performance ◽  
Unpredictable Environment ◽  
And Control

A new wearable parallel robot has been designed and constructed for ankle joint rehabilitation treatments. The robot employs four pneumatic muscle actuators (PMA) together with cables to achieve three rotational degrees of freedom (dof) of its end platform. Parallel topology of the robot, unpredictable environment along with the time varying and non-linear behavior of actuators impose modeling and control challenges which are difficult to comprehend. In this paper an optimal fuzzy dynamic model of the pneumatic muscle has been developed to accurately predict the muscle behavior. The model is capable of mapping the complex relationship in length, force and pressure of the PMA with higher accuracy. This model has been further used to develop a fuzzy control scheme for the ankle robot. Experimental results are obtained to study and model the simultaneous actuation of all the actuators. Comparison with the previous dynamic modeling and control schemes demonstrates an improved performance of the proposed fuzzy controller.

Task-Oriented Servo Loops Control of a 6-DOF Manipulator for Rescue Robot

2013 ◽  
Vol 404 ◽  
pp. 663-667
Author(s):  
Wei Hua Su ◽  
Xu Dong Ren ◽  
Wen Chang Zhang ◽  
Fu Niu
Keyword(s):  
Control Method ◽  
Dynamical Model ◽  
Image Transfer ◽  
Modeling And Control ◽  
Rescue Robot ◽  
Novel Approach ◽  
Proposed Model ◽  
Classical Control ◽  
Task Oriented ◽  
And Control

The thesis research aimed to develop a novel approach to model and control a 6-DOF manipulator for specific tasks. The modeling and control method take into account velocity of the dynamical model. The camera and acquisition system were developed in order to significantly increase the bandwidth of the manipulator. Multi-Input and Multi-Output (MIMO) is used to optimally control the visual loop with respect to the proposed dynamical model. Experimental results on a 6-DOF manipulator for rescue robot are presented that validate the proposed model. Furthermore, a precise synchronization method is used to reduce the delays of image transfer and processing. The experiment results show a biggish improvement of the loop performance with respect to more classical control methods for 6-DOF manipulator.

Modeling and Control for GMA Based on Hammerstein Model Structure

2013 ◽  
Vol 668 ◽  
pp. 406-409
Author(s):  
Qing Song Liu ◽  
Zhen Zhang ◽  
J.Q. Mao
Keyword(s):  
Tracking Control ◽  
Hammerstein Model ◽  
Model Structure ◽  
Hysteresis Model ◽  
Modeling And Control ◽  
Feedforward Loop ◽  
Rate Dependent ◽  
Proposed Model ◽  
Magnetostrictive Actuator ◽  
And Control

A rate-dependent hysteresis model for Giant Magnetostrictive Actuator (GMA) is proposed based on Hammerstein model structure. The Generalized Prandtl-Ishlinskii (GPI) model is used to represent nonlinear block in Hammerstein model. The validity of model is examined by comparsion between simulation results and experimental data. Based on the proposed model, a PID feedback controller combined with an inverse compensation in the feedforward loop is used for tracking control. Experimental results show that the control strategy is effective.

An Economic Analysis of AIDS — Towards a Proposed Model of Costing: A Singapore Experience

1994 ◽  
Vol 7 (3) ◽  
pp. 143-150 ◽  
Author(s):  
JY Lim ◽  
BW Chew ◽  
KH Phua
Keyword(s):  
Economic Analysis ◽  
Hiv Infection ◽  
Control Strategies ◽  
Control Program ◽  
Future Research ◽  
Policy Makers ◽  
Economic Implications ◽  
Proposed Model ◽  
Cost Center ◽  
And Control

With the increasing prevalence of HIV infection/AIDS and the extending range of care and treatment, the economic implications of the various prevention and control strategies, and of treatment, have become the subject of interest to policy-makers, public health specialists and health economists. This paper presents an overview of the methods used for the economic analysis of AIDS/HIV infection. It proposes an activity-oriented, cost center-based model for the costing of the economic impact of AIDS, using cost figures in Singapore since 1985, when the National AIDS Control Program was started. Priorities for future research are also identified. Asia Pac J Public Health1994;7(3):143-50.

Development of a Hybrid Dynamic Model and Experimental Identification of Robotic Bulldozing

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Scott G. Olsen ◽  
Gary M. Bone
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Control Strategies ◽  
Nonlinear Differential Equations ◽  
Model Framework ◽  
Modeling And Control ◽  
Low Level ◽  
Proposed Model ◽  
The Individual ◽  
And Control

The low-level modeling and control of mobile robots that interact forcibly with their environment, such as robotic excavation machinery, is a challenging problem that has not been adequately addressed in prior research. This paper investigates the low-level modeling of robotic bulldozing. The proposed model characterizes the three primary degrees-of-freedom (DOF) of the bulldozer, the blade position, the material accumulation on the blade, and the material distribution in the environment. It includes discrete operation modes contained within a hybrid dynamic model framework. The dynamics of the individual modes are represented by a set of linear and nonlinear differential equations. An instrumented scaled-down bulldozer and environment are developed to emulate the full scale operation. Model parameter estimation and validation are completed using experimental data from this system. The model is refined based on a global sensitivity analysis. The refined model is suitable for simulation and design of robotic bulldozing control strategies.

scholarly journals DYNAMICS OF IL-2 PLASMA LEVELS IN HIV PATIENTS WITH CONSIDERING DRUGS RESISTANCE

2018 ◽  
Vol 8 (2) ◽  
pp. 187-194
Author(s):  
E. S. Eliseeva ◽  
S. P. Kruglak ◽  
L. F. Sklar ◽  
E. V. Markelova ◽  
N. A. Borovskaya
Keyword(s):  
Drug Resistance ◽  
Viral Load ◽  
Antiretroviral Therapy ◽  
Hiv Infection ◽  
Immune Cells ◽  
Interleukin 2 ◽  
Specific Antigen ◽  
Control Group ◽  
Additional Contribution ◽  
Proliferation And Differentiation

Interleukin-2 (IL-2) is one of the most important cytokines involved in the regulation of innate and adaptive immunity. Its main  immunological function is to regulate a specific (antigen-dependent)  immune response by stimulating proliferation and differentiation of  immune cells involved in its realization, including Т-lymphocytes.  Dysfunction of cellular immunity is the main pathogenetic  mechanism for the development of HIV infection.Objective:to  identify patterns of IL-2 levels change in HIV-infected patients on the background of drug resistance at the later stages of infection. The study included 83 patients with HIV infection receiving  highly active antiretroviral therapy; the control group  consisted of 20 healthy blood donors. All patients underwent a study  of the effectiveness of antiretroviral therapy, including an  assessment of HIV viral load and CD4+ Т lymphocyte levels. In  patients with ineffective antiretroviral therapy, a study of drug  resistance to HIV by Senger sequencing was additionally conducted.  According to the results of genome sequencing, HIV-infected  patients with ineffective antiretroviral therapy were divided into two  subgroups — with revealed drug resistance (58.5%) and absence of  detectable resistance mutations in the genome (41.5%). Levels of  IL-2 were measured in all persons included in the study by the  method of enzyme immunoassay. When comparing the levels of IL-2 between groups of patients with continuing viral load on the background of antiretroviral therapy (viral load is detected) with  drug resistance and without it, significant differences were obtained  (1.75±0.26 pg/ml versus 1.95±0.29 pg/ml, p ≤ 0.05, U-criterion,  respectively). The content of IL-2 is statistically significantly lower in  the group of patients who did not succeed with antiretroviral therapy than in the group of patients with treatment efficacy (1.83±0.29 pg/ml versus 4.89±0.55 pg/ml, respectively, p < 0.001, U-criterion). Thus, it is shown that in patients with revealed drug resistance  against the background of progression of HIV infection there is a  decrease in levels of IL-2. The increase in its levels in patients with  HIV infection who have reached virological and immunological  success of therapy is due to the reduction in the number of the cytokine-producing immune cells (T-lymphocytes). We assume that a significant decrease in the levels of IL-2 makes an additional  contribution to the disruption of the processes of proliferation and  differentiation of immunocompetent cells in HIV infection, which is of great importance in the formation of drug resistance of HIV in conditions of constant viral replication.

Modeling and Control of Winding Hybrid-Driven Based Cable-Parallel Manipulator

2013 ◽  
Vol 373-375 ◽  
pp. 111-115 ◽  
Author(s):  
Hui Hui Sun ◽  
Bin Zi ◽  
Sen Qian
Keyword(s):  
Fuzzy Control ◽  
Parallel Manipulator ◽  
Adaptive Fuzzy Control ◽  
Parallel Manipulators ◽  
Kinematics And Dynamics ◽  
Friction Compensation ◽  
Lagrange Method ◽  
Modeling And Control ◽  
Adaptive Fuzzy ◽  
And Control

This paper deals with modeling and adaptive fuzzy control of winding hybrid-driven cable parallel manipulator (WHDCPM). The WHDCPM has the advantages of both the traditional cable-parallel manipulator (CPM) and hybrid-driven based cable-parallel manipulator (HDCPM) since the hybrid-driven planar five-bar mechanism in HDCPM is replaced by winding hybrid-driven five-bar manipulator in WHDCPM. The physical architecture of WHDCPM is determined, and kinematics and dynamics of the cable parallel manipulators have been studied based on Lagrange method. The numerical simulation is demonstrated as an example with adaptive fuzzy control theory, and the diagrams of trajectory tracking, cable tension, friction compensation and motor torque are shown, respectively. The results demonstrate the feasibility and superiority of the WHDCPM.

MODELING AND CONTROL OF DIMENSIONAL QUALITY OF A SERIAL MULTI-STATION MACHINING SYSTEM

2006 ◽  
Vol 13 (05) ◽  
pp. 399-419 ◽  
Author(s):  
SHICHANG DU ◽  
LIFENG XI ◽  
ERSHUN PAN ◽  
JIANJUN SHI ◽  
C. RICHARD LIU
Keyword(s):  
State Space ◽  
State Space Model ◽  
Machining Processes ◽  
Modeling And Control ◽  
Engineering Theory ◽  
Machining Errors ◽  
Proposed Model ◽  
Machining System ◽  
Linear State ◽  
And Control

Modeling and control of dimensional quality is one of deciding factors in current manufacturing competitions, and has always presented a great challenge to both scientists and engineers since for a multi-station machining system, the final product variation is an accumulation from all stations, and the complex non-linear relationship exits between dimensional quality and machining errors. This paper develops a linear state space model using homogeneous transformation to capture the influence of machined errors on dimensional quality, and the explicit expressions for system matrices of the model are explored. The proposed model employs a linear state space form, facilitating the use of the achievements of control theory, information technology and system engineering theory to support engineers supervisory control of physical machining processes, and it also can be used as an analytical engineering tool for efficient and effective faults diagnosis, system plan and design, and optimal sensors allocation. A real machining case illustrates the proposed model.

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