Systems Thinking Approach for Social Problems
01 Jan 2015-
About: The article was published on 2015-01-01. It has received 8 citations till now. The article focuses on the topics: Systems thinking.
Citations
More filters
[...]
TL;DR: In this article , an adaptive backstepping controller with nonlinear disturbance observer is developed to regulate the output voltage of a dc/dc converter feeding a CPL, where an artificial neural network (ANN) methodology is used to estimate the back-stepping control parameters of the buck converter.
Abstract: Buck DC–DC converters are broadly used in DC microgrids to provide a constant dc voltage for generation and storage components. Changing of load condition affects the quality of voltage in the buck DC–DC converters. When constant power loads (CPLs) are used, the stability of these power electronic devices is at risk due to negative impedance characteristics of the CPLs. In such condition, an efficient control method is required to ensure the proper operation of the converter. For this purpose, development of an adaptive control methodology is essential to evaluate the accurate values of controller parameters in the shortest time to damp the ripples quickly. This paper develops a backstepping controller with nonlinear disturbance observer to regulate the output voltage of a dc/dc converter feeding a CPL. An artificial neural network (ANN) methodology is used to estimate the backstepping control parameters of the buck converter. The training ability of the ANN technique prevents the existing controller from depending on the working point of the microgrid. The ANN methodology adapts the controller with various changes and reflections of uncertainties in the microgrid. Case studies are conducted on a dc/dc buck converter in MATLAB/Simulink environment, and the results are verified by the OPAL-RT real-time simulator.
16 citations
[...]
TL;DR: A non-invasive, integrated method for early detection of cellular abnormalities amongst habitual smokers based on analysis of different cyto-morphological features of exfoliative oral epithelial cells is described.
Abstract: Habitual smokers are known to be at higher risk for developing oral cancer, which is increasing at an alarming rate globally. Conventionally, oral cancer is associated with high mortality rates, although recent reports show the improved survival outcomes by early diagnosis of disease. An effective prediction system which will enable to identify the probability of cancer development amongst the habitual smokers, is thus expected to benefit sizable number of populations. Present work describes a non-invasive, integrated method for early detection of cellular abnormalities based on analysis of different cyto-morphological features of exfoliative oral epithelial cells. Differential interference contrast (DIC) microscopy provides a potential optical tool as this mode provides a pseudo three dimensional (3-D) image with detailed morphological and textural features obtained from noninvasive, label free epithelial cells. For segmentation of DIC images, gradient vector flow snake model active contour process has been adopted. To evaluate cellular abnormalities amongst habitual smokers, the selected morphological and textural features of epithelial cells are compared with the non-smoker (-ve control group) group and clinically diagnosed pre-cancer patients (+ve control group) using support vector machine (SVM) classifier. Accuracy of the developed SVM based classification has been found to be 86% with 80% sensitivity and 89% specificity in classifying the features from the volunteers having smoking habit.
12 citations
[...]
TL;DR: In this paper, integrated water resources management (IWRM) and the nexus approach are used to identify solutions for water problems across interdependent sectors with interacting social and natural systems.
Abstract: Integrated Water Resources Management (IWRM) and the nexus approach are tools to identify solutions for water problems across interdependent sectors with interacting social and natural systems. Although both tools aim at solutions for complex water issues using an interdisciplinary approach, IWRM is a management process and the nexus approach is a systems tool to characterize problems. By clarifying their attributes and providing examples, instructors can use them to explain broad social problems and offer practical frameworks for problem-solving. Given their breadth, IWRM and the nexus approach can seem vague and attract criticism, but if they are replaced, the need for them will endure. The concepts are explained, and similarities between them are explored in the paper. Case study sources for them are identified, and the cases are classified by the processes of water resources management as applied across related sectors. How the concepts and their corresponding case studies can be used will vary by context. Suggestions are made for interdisciplinary instruction and discussions in disciplinary settings.
6 citations
[...]
TL;DR: A new technique is proposed to design a Modified PID (MPID) controller for a Boost converter using an interface between LTspice and MATLAB to implement the Particle Swarm Optimization (PSO) algorithm.
Abstract: In this paper, a new technique is proposed to design a Modified PID (MPID) controller for a Boost converter. An interface between LTspice and MATLAB is carried out to implement the Particle Swarm Optimization (PSO) algorithm. The PSO algorithm which has the appropriate capability to find out the optimal solutions is run in MATLAB while it is interfaced with LTspice for simulation of the circuit using actual component models obtained from manufacturers. The PSO is utilized to solve the optimization problem in order to find the optimal parameters of MPID and PID controllers. The performances of the controllers are evaluated for a wide range of operating conditions and different disturbances. The comprehensive simulation results demonstrate the effectiveness and robustness of the proposed method which are also explained through some performance indices.
5 citations
[...]
TL;DR: An experimental investigation into a hybrid back-stepping control proposed for the output voltage regulation of DC-DC buck converter is carried out in this article, where the proposed hybrid control algorithm utilizes a backstepping procedure in conjunction with a robust sliding mode control mechanism to counter both matched and mismatched uncertainties.
Abstract: An experimental investigation into a hybrid back-stepping control proposed for the output voltage regulation of DC-DC buck converter is carried out in this paper The proposed hybrid control algorithm utilizes a backstepping procedure in conjunction with a robust sliding mode control mechanism to counter both matched and mismatched uncertainties An experimental prototype of buck converter is fabricated and controlled with the hybrid control scheme in the laboratory The dynamic response under wide variation of operating points is investigated The control scheme is further extended to a discontinuous conduction mode buck converter which is even more nonlinear in nature A DSP based DS1103 platform is used to conduct experimentation Experimental results demonstrate a satisfactory transient and steady state performance of both output voltage and inductor current
3 citations
Cites background or methods from "Systems Thinking Approach for Socia..."
[...]
[...]
[...]
[...]
[...]