Mihail Abrudean

A Theoretical Study on Modeling the Respiratory Tract With Ladder Networks by Means of Intrinsic Fractal Geometry

Fractional order modeling of biological systems has received significant interest in the research community. Since the fractal geometry is characterized by a recurrent structure, the self-similar branching arrangement of the airways makes the respiratory system an ideal candidate for the application of fractional calculus theory. To demonstrate the link between the recurrence of the respiratory tree and the appearance of a fractional-order model, we develop an anatomically consistent representation of the respiratory system. This model is capable of simulating the mechanical properties of the lungs and we compare the model output with in vivo measurements of the respiratory input impedance collected in 20 healthy subjects. This paper provides further proof of the underlying fractal geometry of the human lungs, and the consequent appearance of constant-phase behavior in the total respiratory impedance.

Rapid prototyping of control systems using embedded target for TI C2000 DSP

The paper presents a digital control application, in which a tuning method is proposed for DC motors, using DSP from Texas Instruments (TI). Experimental application for the DC motor illustrates the effectiveness and the simplicity of the proposed method for controller design. The control algorithm for the drive application runs on a TMS320F2812 DSP. Once the desired functionality has been captured and simulated, using MATLAB/Simulink/Embedded Target for TI C2000 DSP environment can be generated code for the DSP. All task assignments to processor are automatically made by the software. The DC Motor is driven by pulse width modulated (PWM) signals generated by the DSP.

Automation of a distributed generation system

The paper describes the automatic generation control of a distributed generation (DG) system based on the optimal power flow. The optimization technique based on economical and technical considerations is presented. Also, an automation of the DG system is performed using a SCADA software considering the load, the availability of the systems generating units. Also, the optimal power dispatch is presented.

Distributed generation and virtual power plants

The paper describes the main characteristics of distributed generation (DG) and Virtual Power Plants (VPP). Distributed generation refers to the production of electricity near the consumption place using small-scale generating units. The distributed energy resources are renewable energies and cogeneration (simultaneous production of heat and electricity). A Virtual Power Plant is a cluster of DG installations (such as wind turbines, photovoltaic power plants, small hydro etc.) and any other sources of power that can cooperate together in the local area, and are controlled by a central control entity. The VPP is tested for different merit order values and grid connections (on-grid and off-grid) to track if this order is respected.

Control of the blunting process of the residual water from a foundry

In this paper, a variant for the pH control of the residual water from a foundry is presented. The blunting process of the residual water, being a distributed parameters one, is modeled using equations with partial derivatives. For the numerical simulation is used a method based on the matrix of the partial derivatives of the state vector (Mpdx) associated with Taylor series.

Database Globalization in Enterprise Applications

The globalization of a Web application requires storing and accessing data needed by or received from users in different cultures. This paper analyzes three approaches to applying globalization to database models, for flexible support of various locales

Modeling and Simulation of the Gas Absorption Process in the Liquid Phase

In this paper, a solution for the modeling and simulation of the gas absorption process in a liquid is presented. In the modeling procedure, the technological process is decomposed in two sub-processes connected in series, the first sub-process being considered a lumped parameter one, respectively the second sub-process being considered a distributed parameter one. In order to simulate, with a high accuracy, a process that includes in its structure a distributed parameter sub-process, an original method based on the matrix of partial derivatives of the state vector, associated with Taylor series, is used. The modeling-simulation procedure introduces the premise to approximate the concentration value of the gas absorbed in liquid, in relation to the initial pressure from the reactor, respectively the premise of including the technological process in a concentration control structure.

Modelling and numerical simulation examples of distributed parameters processes

Abstract Continuing the papers (Abrudean et al ., 2007), (Colosi et al ., 2006), where the theoretical preliminaries of the definition and use of the M pdx matrix are presented, associated to the Taylor series, for the modelling and numerical simulation of some categories of processes with distributed parameters from power systems, thermoenergetic, electro-energetic, chemical and electromechanical processes, etc, this paper presents a number of four examples. The advantages, the limits and the disadvantages of the method applied to these examples are being underlined.

Microcontroller-based multiple-platform PWM signal generation procedures for industrial use

This contribution describes three procedures and the related software operations which are used to obtain the pulse-width modulation (PWM) signal for industrial use. The hardware platforms used to generate the signals are embedded systems, manufactured in recent years. Three types of microcontrollers based on their register architecture were used: 8-bit ATMEGA 328P, 16bit SAB80C167 and 32-bit PIC32MX320F128H. PWM is a preferred way for control in modern semiconductor devices. The very short rising and falling time ensure the minimum of switching transition time respectively of the switching losses. In this context, the paper will analyze comparatively a new structure, related on a classical reference structure, both the hardware and the software. At the end of the paper some conclusions might be drawn on the code length, system latency and the technical limitations of their usual or rated performance.

Analogical Modeling and Numerical Simulation of the Residual Water Blunting Process Used in Metallurgy

In this paper, an application of the analogical modeling and numerical simulation of the technical processes through the matrix of partial derivatives of the state vector (Mpdx) associated with Taylor series is presented. The residual water blunting process is modeled as a distributed parameters process through the usage of equations with partial derivatives. In this approach the variation of the main output signal of the process (the chemicals pH value) both in relation with time and length of the tanks is considered.