Georgios Lilis

A distributed, event-driven building management platform on web technologies

This paper presents the system architecture of an event-based building management platform. By incorporating the distributed computing technologies in its core, it is able to adaptively scale horizontally without the redesign and the configuration downtime. The commodity hardware and networks used, permit vertical scaling if performance requirements change after the deployment. Additionally, the proposed solution offers an abstraction layer to the management components and the construction framework. This layer is built on modern web technologies facilitating the creation of innovating user driver applications and demand side management coordinators that are universal across the various building structures. Eventually this unification of the high performance management systems and the modern Information and Communication Technology (ICT) shall catalyze the integration of smart buildings in the future smart cities.

Integrating building automation technologies with smart cities: An assessment study of past, current and future interroperable technologies

Future smart cities would integrate a wide range of mostly heterogeneous systems and ICT is an essential asset in the coordination of those. The smart buildings, a major smart cities research and development domain, should advance beyond the complex automation tools and the anticipated energy and comfort envelope. The universal convergence to technologies that would enable the seamless integration with the anticipated smart cities urban environment should be highlighted. Although it is a concept widely accepted for current and future developing standards, it is much less communicated across scientific fields as for example the urban development and building automation. Even worse its necessity, in the latter, is frequently challenged. This paper firstly will try to address the market and scientific criticism towards a fully web-services enabled building in a fair and transparent approach. Secondly it proposes a system as an interoperability layer able to build advanced managements schemes by integrating the assets of current automation and monitoring systems to the Internet backbone.

A mixed-platform framework for Dynamic Stability Assessment

This paper describes a mixed-platform framework dedicated to Dynamic Stability Assessment of power systems. DSA refers to tools capable of characterizing the dynamic stability of the system. Time domain simulation is critical for DSA analysis and is done by algorithms known as TD engines. In this work, operations are shared between a software platform and a hardware one. TD simulation is handled by a dedicated mixed-signal electronics implementation. Data flow control, user interfacing, configuration, result post-processing and other auxiliary operations are realized in software. This architecture combines the flexibility of the software with the high-performance of dedicated hardware. Results of a multi-contingency analysis and a critical clearing time determination analysis for sample test cases are presented. It is demonstrated that an increase in speed of almost three orders of magnitude can be achieved, compared to single-platform solutions.

GeoAware: A hybrid indoor and outdoor localization agent for smart buildings

Localizing, identifying and authenticating the individual occupants is of paramount importance for the future intelligent buildings. Although the performance of outdoor positioning systems is sufficiently good, the indoor ones have still to converge to a universal interoperable technology. This paper proposes a hybrid, unified localization architecture for indoor and outdoor tracking of the building occupants. By taking advantage of the smartphones and their recent near field communication (NFC) capabilities; a low cost, accurate and scalable localization solution is proposed. This system is a module of an existing, modern building management system (BMS) to which it offers location-aware, energy and comfort management capabilities. The solution is currently deployed as a medium scale trial; therefore, the self-energy use, reliability, ease of use and the privacy requirements are of paramount importance. The system analysis in this paper additionally includes accuracy and battery impact assessment in real-world use cases and location-aware building management operations.

JouleSense: A simulation based platform for proactive feedback on building occupants' energy use

A significant amount of energy in the buildings can be saved by inducing efficient occupant behavior. The occupants awareness tools that have been shown to be effective in achieving energy efficiency gains depend on various computational and estimation algorithms. This paper proposes an energy feedback scheme that relies on a model based, building thermal simulation in order to identify the areas for efficiency improvement. By leveraging the specific mathematical formulation of those models and a dedicated open-source solver, improved computational speed, reduced cost and enhanced interoperability is obtained. This combined with the integration into a building management system (BMS), permits real-time sensing and feedback. Unlike similar studies, this works outcome allows the creation of the energy awareness tools that rely solely on validated thermal model simulation, thus increasing their accuracy and potential in the future smart buildings.

Building virtualization engine: A novel approach based on discrete event simulation

This paper proposes and validates a Discrete Event Simulation (DES) engine for the Smart-Building (SB). It strives to virtualize the common elements found within it and integrates them transparently to an existing Building Management System (BMS), along with existing infrastructure. Thanks to this integration layer, the building management and its control intelligence are completely agnostic to the operations of that virtualization engine. A unique feature of this engine is its micro-treading based core. The latter permits a highly optimized, pseudo-concurrent simulation of hundreds building elements (e.g. loads, sensors, storage, generation, user, etc) in a lean, commodity hardware. Primary virtualization aim is the real-time power data of a SB for the purpose of energy management and Smart Grid connectivity. Moreover, energy optimization and financial studies can be conducted proactively, before committing to costly physical infrastructure investments.

An event-driven low power electronics for loads metering and control in smart buildings

The Internet of Things market is experiencing a period of intense growth. From 7 to 10 billion of connected devices in 2013, it is expected to reach 26 to 30 billion in 2020. Smart buildings represent between 2 to 21% of this market. Indeed, the possibility of connecting objects changes the paradigms of measurement, monitoring and management within the building. This paper presents a miniaturized event-driven low power electronics device dedicated to electrical loads in the context of energy management and optimization systems. An electronic device for distributed intelligence is proposed. It is designed and intended to be added in the path of the power supply of existing electrical appliances. This device helps, as well, to perform local processing of measured data in order to provide a dedicated and optimized control of the connected load.

Pipelined Numerical Integration on Reduced Accuracy Architectures for Power System Transient Simulations

This work concerns a dedicated mixed-signal power system dynamic simulator. The equations that describe the behavior of a power system can be decoupled in a large linear system that is handled by the analog part of the hardware, and a set of differential equations. The latter are solved using numerical integration algorithms implemented in dedicated pipelines on a field programmable gate array (FPGA). This data path is operating in a precision-starved environment since is it synthesized using fixed-point arithmetic, as well as it relies on low-precision solutions that come from the analog linear solver. In this paper, the pipelined integration scheme is presented and an assessment of different numerical integration algorithms is performed based on their effect on the final results. It is concluded that in low-precision environments higher order integration algorithms should be preferred when the time step is large, since simpler algorithms result in unacceptable artifacts (extraneous instabilities).