Christos Mourtzios

The rise of Internet of Things (IoT), coupled with the advances in Artificial Intelligence technologies and cloud-based applications, have caused fundamental changes in the way societies behave. Enhanced connectivity and interactions between physical and cyber worlds create ‘smart’ solutions and applications to serve society's needs. Water is a vital resource and its management is a critical issue. ICT achievements gradually deployed within the water industry provide an alternative, smart and novel way to improve water management efficiently. Contributing to this direction, we propose a unified framework for urban water management, exploiting state-of-the-art IoT solutions for remote telemetry and control of water consumption in combination with machine learning-based processes. The SMART-WATER platform aims to foster water utility companies by enhancing water management and decision-making processes, providing innovative solutions to consumers for smart water utilisation.

Internet of Things (IoT) enabled technologies transform industries, envisioned as an ecosystem of billions of interconnected devices. Enhanced connectivity and the rapid development of wireless sensors have caused radical changes on how societies interact and behave. Smart metering, in the context of Smart Cities ecosystem, is advanced by IoT development, aiming at improving citizens' quality of life. Creating cloud-based networks of networked devices requires a low-cost and reliable means for non-IP based devices to seamlessly connect to Internet. Furthermore, device heterogeneity in terms of protocol and data format, hinters large scale deployments and introduce vendor and protocol lock-in issues. This technological gap calls for novel IoT gateways which reliably bridge wireless devices to the Internet. This paper reports an experimental study of a Multi-Protocol gateway which can interact with a plethora of different end devices (water meters, water valves) and constitute the building block of a fixed and wireless network which renders real time telemetry and remote control of water consumption feasible.

In this work a 2×2 multiband, non-uniform Electromagnetic Band Gap (EBG) antenna array is proposed for the realization of a MIMO (Multiple Input-Multiple Output) wireless communication system. It is proved that the strong reduction of mutual coupling among the array's elements, ensured by this EBG lattice type, is capable of enhancing the MIMO channel capacity. The channel impulse response was estimated taking into account the spatial correlation and the antenna characteristics both into one step capacity calculation. Results for the capacity at all three bands of operation (1.99GHz, 4GHz, 5.1GHz) are presented, for various SNR levels, along with respective ones received from antenna arrays with classic Uniform EBG (Mushroom type) and also Perfect Electric Conductor (PEC). The comparison shows clearly the superiority of the proposed hybrid antenna array.

In this paper, a novel approach is attained to the design of low profile antenna structures with wire dipoles and multiband operation. The aim is achieved by utilization of non-uniform Electromagnetic Band Gap (EBG) lattices as reflectors, and this potential comes to be added to the total of special capabilities of this type of Artificial Magnetic Conductors (AMC). It is proved that a properly designed EBG of this type can resonate at more than one frequency and is capable to drive, inside these bands, the dipole to higher order modes of operation besides its basic one. The resulting hybrid radiator apart from its multiband operation exhibits high gain that reaches the value of 9.6 dB, satisfactory Mean Effective Gain (MEG) and very low correlation coefficients, much less than 0.1, between the signals at the input of the dipoles in the case that the radiator is configured as an antenna array. The study of these quantities was performed using the signal characteristics of a real mobile communication environment along with the hybrid antenna properties of operation. The presented analytical results show that the designed radiators are competitive to the classical microstrip ones and can be effectively used in modern wireless communication networks, incorporated either into stationary or into mobile units.

Hybrid antenna configurations, suitable for smart and MIMO antenna systems were synthesized. The antennas are incorporated into novel EBG surfaces with nonuniform layout which, when suitably designed, can enhance the characteristics of operation of antenna arrays positioned in close proximity to their surface. Thus they yield radiating arrangements with very low profile. Theoretical calculation of Mean Effective Gain(MEG) and the Correlation Coefficient among the information signals was made. The presented results prove the effectiveness of this type of hybrid antennas, in giving satisfactory MEG and also very low values of correlation coefficients.