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Controlled islanding, also known as system splitting, can effectively prevent blackouts of power system by separating it into two or more islands. To make each island reach steady state point by available measures, each island must be observable. This paper proposes a new modified three phase method to find proper splitting strategy, considering observability as a new constraint, to minimize effect of system splitting on network observability. Some techniques about strategy searching are introduced to increase its speediness and related algorithms are described in detail in this thesis. The simulation results presented show efficiency of method in finding proper splitting strategies. In the... 

Wide-area measurement system (WAMS), which is enabled by broad installation of phasor measurement units (PMUs), is a novel solution for the secure and reliable operation of modern power systems. The adequate number and appropriate location of PMUs has been introduced as a challenging research area in recent years. This dissertation is the first effort to assess the cost/worth analysis of WAMS design and PMU locationing in a probabilistic manner. In the studies conducted here, power network monitoring and control associated with the energy management system (EMS), among miscellaneous applications of WAMS, have been taken into consideration. First, the conventional deterministic definition of... 

The level of current and voltage harmonics in power networks has been increased due to the widespread use of power electronic equipment. This increase may, in turn, result in damage to power system equipment in addition to extra power losses in the network. In order to assess the level of harmonics, it is required to monitor power networks using power quality analyzers. However, due to the high costs, only limited number of measurements can be used in practice. The task of harmonic state estimation is to identify the location and magnitude of harmonic sources and to estimate the harmonic voltage and current by partial measurements. Due to the high price of measurement instruments and... 

Earlier in the philosophical tradition, the realists’ view that world exist in itself, independently of our knowledge, had been challenged by idealists, who denied such existence and considered the world and its objects as a function of (our) perception. Today, some philosophers have challenged the (scientific) realists’ belief in the existence of scientific unobservable entities, such as electrons, quarks, forces, gravitational fields, cells, bacteria, genes and so on, that are posited by the modern scientific theories. The debates which have been made in this regard, in recent decades, have spurred an important controversy known as “scientific realism and antirealism debate” in the field... 

In recent decades, the study of Nano and Micro Electromechanical Systems (NEMS and MEMS) as in micro sensors and actuators or in Atomic Force Microscopes (AFM) attracted considerable attention. Since an indispensable part of such systems is a nano or micro flexible beam, the inevitable undesirable vibrations of the flexible beam necessitate the implementation of vibration control strategies. Recently, some cutting edge experiments on statics and dynamics behavior of micro beams have been conducted that reveal some deviations from the prediction of classical theories, and hence this leads to development of strain gradient elasticity theory. In addition, the often-adopted finite dimensional... 

The problem of spacecraft attitude determination (AD) using thermal data is investigated. Given the Solar space environment, the key dominant mechanism of heat transfer will be radiation, in which the Sun and Earth are the major contributing heat sources that affect the satellite external surface temperatures. In this sense, the net heat fluxes (NHF) of a satellite surface that is insulated against any internal heat communication will only be related to these main radiating sources. In order to utilize the satellite temperature data for AD, a heat attitude model (HAM) that relates the satellite surfaces NHF to its attitude is developed using three orthogonal satellite surfaces. Assuming... 

In this thesis, we study the observability and stability problems of networked control systems (the control systems which communicate through communication channels) to answer two important questions about different system models. The first is that what is the constraints implied by the stability or observability of systems? (necessary condition on the observability and stability). The second is that under which constraints can we present a design for system to guarantee the observability or stability of systems? (sufficient condition on the observability and stability). Clearly, an efficient design is the one that presents a tight sufficient condition.One of system models addressed in this... 

One of the main arguments between scientific realists and scientific anti-realists is about observability. As a prominent anti-realist, van Fraassen and his theory of constructive empiricism and his views on observability and the use of scientific instruments, have been the subject of many debates. He believes that observation is the sole path to knowledge and observation is only possible through unaided human eye, so seeing through scientific instruments like microscopes does not count as observation, therefore the information gained from these procedures are not necessarily true.This thesis not only examines van Fraassen’s outlooks on the matter, but also examines his opponents’ view and...