Efficient redundancy in wired and wireless S2A architectures for NCS

This thesis focuses on the integration of wired and wireless nodes running on top of Gigabit Ethernet and WiFi respectively in Networked Control Systems. Such a networked control system investigated in this work consists of two wireless sensors, two wireless actuators, 14 wired sensors, two wired actuators and one wired supervisor. The architecture is based on Sensor-To-Actuator model. It is revealed through OMNeT++ simulations that the wired and wireless packet end-to-end delays in the developed model satisfy system requirements with no packet loss. Moreover, wired, wireless and mixed interferences are studied and quantified. The amount of interference that the model can withstand is determined. All results are subjected to a 95% confidence analysis. Additionally, the thesis focuses on reliability in the design of networked control systems that is becoming greatly important. Fault-tolerance is often used to increase system reliability. In this work, Triple Modular Redundancy (TMR) and Parallel Redundancy Protocol (PRP) are both applied to a Sensor-to-Actuator architecture with 16 sensors, four Actuators and one Supervisor. Two of the 16 sensors as well as two of the four actuators are wireless while the rest of the nodes are wired. It is first shown that this NCS succeeds in meeting all control system requirements (zero packet loss and bounded end-to-end delay). Reliability models are then developed to help designers choose the appropriate mix of fault-tolerant techniques in order to maximize lifetime while at the same time minimizing the extra cost due to the added redundancy

Greater Cairo Earthquake Loss Assessment and its Implications on the Egyptian Economy

This study develops a loss estimation model for assessing the seismic economic implications resulting from damage to Greater Cairo’s building stock, as well as natural gas and electricity lifelines. The model estimates both the direct and indirect economic losses resulting from seismic occurrences. The developed model is composed of three modules. The first of which is the ground shaking module which estimates ground-motion throughout Greater Cairo. This is done through investigating the seismicity of Egypt and its surroundings, in order to develop recurrence relationships. Furthermore, through the use of geological and geotechnical data, seismic geological classification is conducted. This investigation is used along with three attenuation relationships to estimate ground-motion throughout Greater Cairo. The second module evaluates the damage to the building stock as well as natural gas and electricity lifelines. This is done through developing a building inventory database, and classifying structures in this database according to various classes. Moreover, data regarding components in the natural gas and electricity networks is collected, and through the use of minimum cut sets the networks’ behaviour is assessed. Finally, through the use of fragility curves the vulnerability of structures and components is evaluated. The final module estimates the direct economic losses associated with repairing damaged components. Furthermore, the indirect costs associated with business interruption resulting from disruption to elements in the built environment are also estimated. This study will pave the way for developing countries to recognize the impacts of earthquakes on their economies. Moreover, it will be useful for countries that exhibit a centralized economy that is dependant on major cities. Furthermore it provides a step forward in earthquake loss estimation to model multiple lifelines, rather than past research which modelled each lifeline separately