Sharif Digital Repository

A mathematical model helps to understand any system with any level of complication, such as the human body. The heart, vascular system, and lungs are three important parts of each body that life is impossible without them. The performance of the cardiovascular and respiratory systems is tuned by a group of complex mechanisms which are called regulatory mechanisms. Therefore, a model which describes the behavior of these mechanisms has great importance. The goal of this research is to provide and simulate the newest and most complete model in this field. The presented model should consist of the heart, vascular system, lungs, respiratory system, gas exchange and transport, and finally... 

A genetic-based pore network extraction method from micro-CT images is proposed in this work. Several variables such as the number, radius and location of pores, the coordination number, as well as the radius and length of the throats are used herein as the optimization parameters. Two methods are presented for modeling the pore network structure. Unlike the previous models, these methods are directly based on minimizing the error between the extracted network and the real porous medium. This leads to the generation of more accurate results while reducing required computational memories. Two different objective functions are used in building the network. In the first method, only the... 

The environmental impact of process plants is one of the causes of the environmental disturbance in the world. Including the effects of these destructive impacts can be mentioned to the phenomena such as global warming, climate change, severe air pollution and water shortage. Hence, the economic justification of a process, without the review of relevance of its environmental impacts, it does not lead to the implementation and construction of a process plant. For this reason, it is a requirement to provide a software platform (preferably object-oriented) for quick and automatic checking of this item and the exact determining of these effects. On the other hand, due to the complexity of the... 

Process optimization is a technique by which the plant operating condition is obtained such that a specific objective is achieved while the other process requirements are still met. These requirements can include product quality specifications, physical equipment limitations, and the constraints corresponding to the environmental, health, and safety issues. Frequently, this objective is an economic one. In the process optimization, the use of improper optimization techniques may lead to impractical results. One of these strategies is the plant wide optimization. In order to show the effect of plant wide optimization, one should use a complicated enough process as a bench mark of the... 

Simulation of biological behaviors as the pre requirement for control and optimization, especially for recognition and treating diseases, requires studying involved reactions which may or may not be accessible. In the other side, finding the correct network structures and related mathematical expressions to simulate biological behaviors is a complicated problem due to multi aspect interactions among biological reactions, which imply an approach that integrate the knowledge coming from multiple discipline including biological concepts, mathematical modelling, bioinformatics and advanced programming. In this study we aim to analyze this problem using ontological inference to develop a... 

Gas transmission networks, as one of the most important energy transport networks, are used to transport gas from production facilities to major gas consumers. These networks possess very complex behavior due to their severely nonlinear equations, their temporal and spatial broadness, the compressibility feature of the fluid that passes through them, and their relationship and interdependency with other energy material generation, transportation, and distribution infrastructures through multi-vector energy systems. Hence, the management and coordination of these networks are challenging. In this regard, the most demanding problem of such networks is their expansion planning due to the... 

Monitoring and control of gas transmission networks are very challenging and important, this is due to the fact that interactions between various elements in the transmission network severely affect network’s overall performance. This makes it crucial for the monitoring and control systems to take into account the topology of the network, in their decision making and control scenario’s. On the other hand, in the event of any abnormality in the network behavior, , in order to accurately and quickly detect the cause of the abnormal conditions, there is a need for rapid and effective analysis of the network based on the measurements made therein and to identify the key and effective situations... 

Identification and control of nonlinear systems have been always such important subjects based on nonlinearities of many processes. For instance, identification and control of gas transmission networks can be mentioned as one of the challenging problems related to their complexity and existence of different variables. The purpose of this project is identification of a nonlinear model for defining a gas transmission network and implementing a model predictive control algorithm based on identified model. Hence, first, a volterra model is implemented for identification of a pH neutralization process and then, that model is used for identification of a gas transmission network. Finally, by... 

Total Energy consumed in the compressor stations severely affects the gas transmission costs. Currently steady-state optimizations are used to solve “Minimize Fuel Cost Problem” (MFCP) in gas transmission networks. But due to the fast changing demand and maintaining the linepack of network, these methods are not able to find best solution for MFCP. Control of natural gas transmission system is a challenging task due to the system large dimension, lots of operating constraints and small number of measurements compared to the number of system states. In this thesis it is first shown that most of the pipeline systems have a mild nonlinear behavior. A heuristic method for identification of large... 

The kidney is one of the most complicated organs in terms of structure and physiology, in part because it is highly vascularized. Previous investigations have focused on specific characteristics like length and diameter. There are a few methods like those which are based on image processing techniques, that have been focused on all features as a unique structure. The clear drawback of these approaches is inability to justify growth and changes. Lindenmayer system (L-system) is parallel rewriting method and a type of graph grammars. L-system can justify growth and all characteristic changes and adopt itself to them. Parametric rewriting rules incorporating within physiological laws of the... 

Three different feedback linearization control methods are applied to nonlinear control of type I diabetes mellitus model. One is exact FBL and the two others are approximate manners based on approximations of the nonlinear system and its duality one-form, utilizing uniform approximation and a homotopy operator, respectively. An extended luenberger observer is also employed to observe the required states of designed compensators. The nonlinear compensators are designed based on a minimal model and applied to the minimal model, as well as Sorensen’s physiological model. In addition to the mentioned close-loop control strategies, a discrete control strategy based on an optimization problem is... 

Gas transmission networks play an important role in multi-vector energy networks. Therefore, reliable and efficient control of gas transmission networks with the minimum energy consumption is utmost task and is still an active research area. This work, introduces a distributed, model-free, and game-theoretic approach comprising a simultaneous game followed by a sequential game, to achieve the control objectives in gas transmission networks. The cooperative game approach is adopted for this purpose. In the proposed method two fuzzy inference systems have been used to obtain the payoff of each player in the game of gas transmission network control, the first one has been used to determine the... 

Whenever continuous and discrete dynamics interact, hybrid systems arise. Basically, models of such systems consisted of differential or difference equations to represent continuous dynamics and automata or other discrete variables to describe behavioral mode of the systems. Our main concern is focused on two types of hybrid systems: Discrete controllers which are combined with continuous physical process like biological systems can often be well described by hybrid systems. Our approach in this thesis deals with optimal multiple daily insulin injections which are introduced as an offline control approach on a simulated patient with type I diabetes. Simulated patient is provided via GlucoSim... 

Natural Gas is one of the most important energy resources in the world. The U.S energy information administration(EIA) has reported that natural gas consumption will increase until 2030 in all participating sectors including industrial, domestic and electricity production.Although the use of natural gas as a source of energy has many advantages, natural gas physical condition made it’s transfer so challenging. Among the various types of transmission methods, using pipline is so conventional. Natural gas can be transmited through pipelines in a safe and reliable manner upto thousands of kilometers. For this reason, operation monitoring and control of gas transmission networks are so... 

Digital analysis of reservoir rocks prepares a powerful tool in the field of porous media studies and provides appropriate information of single / multiphase flows by performing numerical simulations on porous media images. In order to access the necessary tools to benefit from digital rock analysis and characterization, we need accessing the porous media images, the geometric distribution and the spatial distribution of pores and grains through imaging or reconstruction methods. Porous media reconstruction methods are known as an alternative to imaging techniques. In addition, reconstruction methods have the ability to fix problems and imperfections associated with imaging, such as... 

Kidney is one of the most complicated organs in terms of functionality and physiology due to its complicated unique vascular structure. Previous investigations have focused on specific characteristics like length and diameter. Most of these methods are based on Image Processing techniques which prevent a comprehensive study in growth and changes of the vascular system. Lindenmyaer system (L-system) is a parallel rewriting system and a type of formal grammar and had been used to create graphs and natural patterns. By absorbing the physiological characteristics of the kidney and integrating them into parametric L-system, a highly dense and accurate vascular system could be generated with few... 

Increasing demand for natural gas in various parts of energy sectors results in the rapid boost of analysis tools necessitates the development of the appropriate pieces of software for both simulation and optimization of the transient behavior of the gas transmission networks as an important part of the gas industries. The main objective of this project was the development of a dynamic and compositional simulator in an extensible, robust, reusable and yet maintainable manner. To achieve this goal, the object-oriented approach was used as the software development paradigm. After going through the analysis and design of this software based on an object-oriented methodology, it has been... 

An anatomically accurate model of conducting airways is essential for adequately simulating gas mixing and fluid distribution. In the current study, Lindenmayer systems (L-systems) as a type of graph grammars method has been formulated to generate bronchial tree structure in human lung. It has been considered that the structure of bronchial tree is divided into two main parts: 1) The central airways (from the trachea to segmental bronchi); and 2) the dichotomous branching structure (from segmental bronchi to alveolar duct). Nine parametric rewriting rules incorporating within physiological laws of the airway branching are used to generate each parts of the bronchial tree. Comparison of the... 

The industrial paradigm shift toward intelligent and sustainable management stimulates policymakers to leverage artificial intelligence for the decentralized planning of chemical industries with energy networks. By doing so, this work firstly presents a simulation framework to investigate the rigorous transient behavior of integrated systems comprising natural gas and power transmission networks, along with a chemical plant whose feedstock is natural gas. This framework entails dynamic models for the gas transmission network and the SynGas plant, and a continuous-time AC-power flow formulation with dispatchable loads. It addresses the following key challenges: (i) analyzing energy and... 

Monitoring of natural gas transmission networks, is one of the necessities for efficient, safe, and economical operation of energy supply networks. In order to efficiently control and monitor the operation of gas transmission network, various states of the network (like temperature, pressure, and flow) should be available. Among these states, some can be easily measured, and the rest should be estimated based on these measurements throughout the network. In this project, an algorithm to obtain near optimal locations of various measuring devices has been proposed. Furthermore, a method for estimation of the states of transmission network based on these measurements and Machine Learning has...