George Nikolakopoulos

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This study addresses the control problem of an unmanned quadrotor in an indoor environment where there is lack of absolute localisation data. Based on an attached inertia measurement unit, a sonar and an optic-flow sensor, the state vector is estimated using sensor fusion algorithms. A novel switching model predictive controller is designed in order to(More)
The power awareness issue is the primary concern within the domain of Wireless Sensor Networks (WSNs). Most power dissipation ocurrs during communication, thus routing protocols in WSNs mainly aim at power conservation. Moreover, a routing protocol should be scalable, so that its effectiveness does not degrade as the network size increases. In response to(More)
This article addresses the control problem of quadrotors in environments where absolute-localization data (GPS, positioning from external cameras) is inadequate. Based on an attached IMU and an optical flow sensor the quadrotor's translational velocity is estimated using an Extended Kalman Filter. Subject to the velocity measurements, the roll, pitch and(More)
Epigenetic aberrations are increasingly regarded as key factors in cancer progression. Recently, deregulation of histone acetyltransferases (HATs) has been linked to several types of cancer. Monocytic leukemia zinc finger protein (MOZ) is a member of the MYST family of HATs, which regulate gene expression in cell proliferation and differentiation.(More)
In this article modeling approaches for networked controlled systems (NCS) with different types of varying communication latency times are presented. The embedded delays are unknown, bounded and depending on their size relative to the sampling period, four different models are offered. There is distinct treatment for delays longer than one sampling period,(More)
In the past fifty years, several attempts have been made to model the characteristics of Pneumatic Artificial Muscles (PAMs). PAM models based on their geometrical properties are the most commonly found ones in the scientific literature. In the process of deriving those models a lot of assumptions and simplifications are made due to the fact that PAM is a(More)
In this article a scheme for image transmission over Wireless Sensor Networks (WSN) with an adaptive compression factor is introduced. The proposed control architecture affects the quality of the transmitted images according to: (a) the traffic load within the network and (b) the level of details contained in an image frame. Given an approximate(More)
In this article a switching model predictive control scheme for an articulated vehicle under varying slip angles is being presented. For the non-holonomic articulated vehicle, the non-linear kinematic model that is able to take under consideration the effect of the slip angles is extracted. This model is transformed into an error dynamics model, which in(More)
The aim of this article is to present an optimal model for the behavior of a tilt wing aircraft during its transition state. A tilt wing aircraft is a hybrid between a helicopter and a plane, which has the capabilities of both parts, meaning that it can stand still and hover and by tilting its wing 90 degrees to act like a regular plane. Overall, a tilt(More)
In this article, a novel on-line path planning algorithm for an articulated vehicle, moving in a partially known and sensory based reconstructed environment, and relying on Model Predictive Control will be presented. The proposed algorithm belongs to the family of bug like path planning algorithms and has the capability to take under consideration the real(More)