@article {18566, title = {Impact of Failure Prediction on Availability: Modeling and Comparative Analysis of Predictive and Reactive Methods}, journal = {IEEE Transactions on Dependable and Secure Computing}, year = {2018}, pages = {1-1}, abstract = {Predicting failures and acting proactively have a potential to improve availability as a correct prediction and a successful mitigation may bring a reward resulting in decrease of downtime and availability improvement. But, conversely, each incorrect prediction may introduce additional downtime (penalty). Therefore, depending on the quality of prediction and the system parameters, predictive fault-tolerance methods may improve or may degrade availability in comparison to the reactive ones. We first derive taxonomies of fault-tolerant techniques and policies to differentiate between reactive and proactive policies that are further classified as systematic and predictive. To evaluate whether a predictive policy improves availability or not, we derive an analytical model for availability quantification. We use Markov chains to extend steady-state availability equation to include: precision and recall, penalty and reward, mitigation success probability and potential failure rate increase due to the prediction load. We also derive A-measure to optimize failure prediction for increasing availability. In our conclusion, precision and recall have comparable impact on availability as changing MTTF and MTTR. To validate the model we also simulate and analyze availability of a virtualized server with exponential distribution of failure and repair rates.}, keywords = {Analytical models, availability, Computational modeling, failure, fault tolerance, Fault tolerant systems, Mathematical model, modeling, Optimization, prediction, predictive, Predictive models, proactive, Servers}, issn = {1545-5971}, doi = {10.1109/TDSC.2018.2806448}, author = {Kaitovi{\'c}, Igor and Malek, Miroslaw} } @article {18455, title = {A Framework for Disturbance Analysis in Smart Grids by Fault Injection}, journal = {Springer Journal on "Computer Science - Research and Development"}, year = {2016}, month = {09/2016}, abstract = {With growing complexity of electric power systems, a total number of disturbances is expected to increase. Analyzing these disturbances and understanding grid{\textquoteright}s behavior, when under a disturbance, is a pre-requisite for designing methods for boosting grid{\textquoteright}s stability. The main obstacle to the analysis is a lack of relevant data that are publicly available. In this paper, we design and implement a framework for emulation of grid disturbances by employing simula-tion and fault-injection techniques. We also present a case study on generating voltage sag related data. A foreseen usage of the framework considers mainly prototyping, root-cause analysis and design and comparison of methods for disturbance detection and prediction. }, issn = {1865-2042}, doi = {10.1007/s00450-016-0313-8}, url = {http://dx.doi.org/10.1007/s00450-016-0313-8}, author = {Kaitovi{\'c}, Igor and Obradovi{\'c}, Filip and Lukovi{\'c}, Slobodan and Malek, Miroslaw} } @conference {18503, title = {A Methodology for Proactive Maintenance of Uninterruptible Power Supplies}, booktitle = {Latin-American Symposium on Dependable Computing (LADC2016) - Workshop on Dependability in Evolving Systems (WDES)}, year = {2016}, month = {10/2016}, address = {Cali, Colombia}, abstract = {We propose a methodology for proactive maintenance of Uninterruptible Power Supply (UPS) devices based on online health-status monitoring and application of data analytics for prediction of UPS components{\textquoteright} failures. The goals of the work are (i) improvement of reliability of UPS devices by ensuring prompt action prior to a failure of a component, and (ii) provision of more cost-effective maintenance by servicing the device only when required instead of periodically. Improving reliability of UPS{\textquoteright}es also enhances dependability of critical infrastructures that require high quality power supply.}, author = {Lukovi{\'c}, Slobodan and Kaitovi{\'c}, Igor and Lecuona, Gerardo and Malek, Miroslaw} } @conference {18454, title = {Optimizing Failure Prediction to Maximize Availability}, booktitle = {13th IEEE International Conference on Autonomic Computing (ICAC)}, year = {2016}, month = {07/2016}, address = {W{\"u}rzburg, Germany}, abstract = {Availability of autonomous systems can be enhanced with self-monitoring and fault-tolerance methods based on failures prediction. With each correct prediction, proactive actions may be taken to prevent or to mitigate a failure. On the other hand, incorrect predictions will introduce additional downtime associated with the overhead of a proactive action that may decrease availability. The total effect on availability will depend on the quality of prediction (measured with precision and recall), the overhead of proactive actions (penalty), and the benefit of proactive actions when prediction is correct (reward). In this paper, we quantify the impact of failure prediction and proactive actions on steady-state availability. Furthermore, we provide guidelines for optimizing failure prediction to maximize availability by selecting a proper precision and recall trade-off with respect to penalty and reward. A case study to demonstrate the approach is also presented.}, author = {Kaitovi{\'c}, Igor and Malek, Miroslaw} } @conference {18379, title = {Proactive Failure Management in Smart Grids for Improved Resilience (A Methodology for Failure Prediction and Mitigation)}, booktitle = {IEEE GLOBECOM SmartGrid Resilience (SGR) Workshop}, year = {2015}, month = {12/2015}, address = {San Diego, CA, USA}, abstract = {A gradual move in the electric power industry towards Smart Grids brings several challenges to the system operation such as preserving its resilience and ensuring security. As the system complexity grows and a number of failures increases, the need for grid management paradigm shift from reactive to proactive is apparent and can be realized by employing advanced monitoring instruments, data analytics and prediction methods. In order to improve resilience of the Smart Grid and to contribute to efficient system operation, we present a blueprint of a comprehensive methodology for proactive failure management that may also be applied to manage other types of disturbances and undesirable changes. The methodology is composed of three main steps: (i) continuous monitoring of the most indicative features, (ii) prediction of failures and (iii) their mitigation. The approach is complementary to the existing ones that are mainly based on fast detection and localization of grid disturbances, and reactive corrective actions.}, keywords = {Failure Prediction, Proactive Management, Resilience, security, smart grid, Synchrophasor}, author = {Kaitovi{\'c}, Igor and Lukovi{\'c}, Slobodan and Malek, Miroslaw} } @conference {18378, title = {Unifying Dependability of Critical Infrastructures: Electric Power System and ICT (Concepts, Figures of Merit and Taxonomy)}, booktitle = {IEEE Pacific Rim International Symposium on Dependable Computing (PRDC)}, year = {2015}, month = {11/2015}, address = {Zhangjiajie, China}, abstract = {With Smart Grids efficiency of the electric power delivery service can be significantly increased by using advanced ICT infrastructure. The looming danger of merging two critical infrastructures, ICT and electric power, is that dependability may be compromised due to interdependencies and different approaches to dependability in the two communities. This calls for a unified approach to dependability which may be achieved by viewing Smart Grids as cyber-physical systems. We analyze and compare definitions and figures of merit used in ICT and electric power systems{\textquoteright} communities to provide the basis for dependability analysis of Smart Grids. We propose a taxonomy of faults for Smart Grids by examining a large set of previous power system outages. Our work relies on the analysis of relevant events from the past in an attempt to understand present dependability state of Smart Grids and pave the way for proactive grid management.}, keywords = {Critical Infrastructures, Cyber-Physical, Dependability, Fault Taxonomy, smart grid}, author = {Kaitovi{\'c}, Igor and Lukovi{\'c}, Slobodan and Malek, Miroslaw} } @conference {18233, title = {Modeling Requirements For Security-enhanced Design of Embedded Systems}, booktitle = {ICETE SECRYPT}, year = {2014}, month = {08/2014}, publisher = {ICETE}, organization = {ICETE}, address = {Vienna, Austria}, author = {Ferrante, Alberto and Kaitovi{\'c}, Igor and Milosevic, Jelena} } @conference {18251, title = {Smart Charging Cell for Smart Cities}, booktitle = {The 2nd IEEE International Workshop on Intelligent Energy Systems (IWIES) }, year = {2014}, month = {08/2014}, abstract = {Energy consumption can be to some extent steered not only in time but in special cases in space as well. This mostly concerns electric vehicles (EV) charging. In this work we present conceptual solution of a {\textquoteleft}GeoGreen Cell{\textquoteright} developed in scope of an international project {\textendash} Ge(o)Green. The main purpose of such an aggregation is to efficiently coordinate. EV charging with respect to price of energy both in time and space. Even though massive acceptance of EVs seems far, there is an emerging need for conceptual solutions and reference models of solutions for their seamless integration into energy system in particular in urban areas. In fact, system level models of the supporting ICT architecture, including structural and behavioral ones, have been developed. The models have been verified by means of simulations to assure their correctness. Scheduling optimization algorithms have been created and the system has been validated by means of system-level simulations.}, keywords = {aggregation, EV charging, structural and behavioral models, SyML}, author = {Lukovi{\'c}, Slobodan and Kaitovi{\'c}, Igor} } @conference {17729, title = {A Model for the Evaluation of User-Perceived Service Properties}, booktitle = {International Symposium on Parallel Distributed Processing, Workshops and Phd Forum (IPDPSW)}, year = {2013}, month = {May}, publisher = {IEEE Computer Society}, organization = {IEEE Computer Society}, address = {Boston, Massachusetts, USA}, abstract = {An ever-increasing number of both functional and non-functional requirements has resulted in growing system complexity which demands new solutions in system modeling and evaluation. As a remedy, service-oriented architecture (SOA) offers services as basic building elements of system design. Service dependability is highly dependent on the properties of the underlying information and communications technology (ICT) infrastructure. This is especially true for the user-perceived dependability of a specific pair service client and provider as every pair may utilize different ICT components. We provide a model for the description of ICT components and their non-functional properties based on the Unified Modeling Language (UML). Given a service description, a network topology model and a pair service client and provider, we propose a methodology to automatically identify relevant ICT components and generate a user-perceived service infrastructure model (UPSIM). We demonstrate the feasibility of the methodology by applying it to parts of the service network infrastructure at Universit{\`a} della Svizzera italiana, Switzerland. We then show how this methodology can be used to facilitate user-perceived service dependability analysis.}, keywords = {availability, design engineering, metamodeling, modeling, object oriented modeling, quality of service (QoS), service dependability, service network management, service networks}, isbn = {978-0-7695-4979-8}, doi = {10.1109/IPDPSW.2013.163}, url = {http://andreas-dittrich.eu/2013/03/a-model-for-the-evaluation-of-user-perceived-service-properties}, author = {Dittrich, Andreas and Kaitovi{\'c}, Igor and Murillo, Cristina and Rezende, Rafael} } @conference {18054, title = {STRATOS: open System for TRAcTOrs{\textquoteright} autonomous OperationS}, booktitle = {EFITA Internation Conference on Sustainable Agriculture through ICT Innovation }, year = {2013}, month = {06/2013}, publisher = {European Federation for Information Technology in Agriculture, Food and the Environment}, organization = {European Federation for Information Technology in Agriculture, Food and the Environment}, address = {Torino, Italy}, abstract = {This paper describes the objectives and final results of the STRATOS project (System for TRAcTOrs{\textquoteright} autonomous OperationS), within the framework of ICT-AGRI ERA-NET (Coordination of European Research within ICT and Robotics in Agriculture and related Environmental Issues). The main objective of the STRATOS project was the development of an open ICT hardware-software infrastructure enabling the acquisition of geo-referenced information on soil and terrain parameters. In more detail, STRATOS project target was to develop and demonstrate new functions enabled by ISOBUS technology (ISO 11783) that support a substantial improvement of the quality of the farming jobs. In particular the idea is to develop a technology based on ISOBUS compliant, wireless self-powered sensor network for the real time measurement of soil and harvester conditions. In this way, Task Controller (an ICT component defined by ISOBUS specification which supervises actively the farming job performed by the tractor) can optimize the whole tractor and implement operational modes to improve the farming job quality and safety of the overall systems. The project lasted from 1st April, 2011 to31st March, 2013, and this paper reports about the project achievements.}, keywords = {agriculture, ICT, model-driven approach, precision farming, Safety}, author = {Fantuzzi, Cesare and Gutman, Per-Olof and Kaitovi{\'c}, Igor and Larcher, Luca and Marzani, Stefano and Ruggeri, Massimiliano and Zagurskis, Valerijs} } @inbook {18089, title = {Systems Engineering for Assessment of Virtual Power System Implementations}, booktitle = {Artificial Intelligence Applications and Innovations}, series = {9th IFIP WG 12.5 International Conference, AIAI 2013, Paphos, Cyprus, September 30 {\textendash} October 2, 2013, Proceedings}, volume = {412}, year = {2013}, pages = {667-676}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, abstract = {In this work we present an adoption of systems engineering methodology for design and assessment of a Virtual Power System (VPS). The VPS has been defined as an aggregation of distributed energy resources, consumers and storages which can operate autonomously, and is presented to the power system as a single unit in technical and commercial terms. The complexity of these critical systems is tackled by means of systems engineering. We have applied our approach in scope of a research project AlpEnergy.}, keywords = {assessment, modeling, SysML, systems engineering, VPS}, isbn = {978-3-642-41141-0}, issn = {1868-4238}, doi = {10.1007/978-3-642-41142-7_67}, author = {Lukovi{\'c}, Slobodan and Kaitovi{\'c}, Igor} } @conference {17732, title = {Model-driven approach to design ICT infrastructure for precision farming}, booktitle = {17th IEEE Conference on Emerging Technologies and Factory Automation (ETFA)}, year = {2012}, month = {09/2012}, publisher = {IEEE Industrial Electronics Society}, organization = {IEEE Industrial Electronics Society}, address = {Krak{\'o}w, Poland}, abstract = {Design of complex systems involving a number of experts from various fields necessarily includes modeling at different levels of abstraction. Modeling is particularly important in the initial phase of a joint project when all system requirements and constraints have to be clearly defined and understood by all the partners. Once an unambiguous structural model has been achieved and components interfaces fixed, design of components can be done independently. For the initial phase, a very simplified modeling methodology based on UML that can be easily understood and applied has been proposed. The application of the methodology has been presented through the design of full structural model of the infrastructure for precision farming. Modeled infrastructure is an open ICT hardware-software solution based on ISOBUS specification, that enables partial automation of tractors increasing safety and production efficiency. Model achieved through several steps presents a mutual understanding platform between the partners. Most importantly, a precise model has been achieved without the necessity of in deep study of UML by all the partners.}, keywords = {agriculture, ICT infrastructure Design, ISOBUS, model-driven approach, precision farming, Safety, Unified Modeling Language}, isbn = {978-1-4673-4736-5}, doi = {10.1109/ETFA.2012.6489709}, author = {Kaitovi{\'c}, Igor and Rezende, Rafael and Murillo, Cristina and Fantuzzi, Cesare} } @conference {18140, title = {STRATOS: Open System For Tractors{\textquoteright} Autonomous Operations}, booktitle = {5th International Conference on Automation Technology for Off-road Equipment (ATOE)}, year = {2012}, month = {07/2012}, pages = {162-187}, publisher = {International Commission of Agricultural and Biosystems Engineering (CIGR)}, organization = {International Commission of Agricultural and Biosystems Engineering (CIGR)}, address = {Valencia, Spain}, abstract = {This paper describes the objectives and preliminary results of the STRATOS project (System for TRAcTOrs{\textquoteright} autonomous OperationS), within the framework of ICT-AGRI ERA-NET (Coordination of European Research within ICT and Robotics in Agriculture and related Environmental Issues). The main objective of the STRATOS project is to develop an open ICT hardware-software infrastructure enabling the partial automation of tractors and at the same time enhancing their operational safety and production efficiency, with the positive effects of reduced accident risk and environmental impact. In more detail, STRATOS project target is to develop and demonstrate new functions enabled by ISOBUS technology (ISO 11783) that support a substantial improvement of the quality of the farming jobs. In particular the idea is to develop a technology based on ISOBUS compliant, wireless self-powered sensor network for the real time measurement of soil and harvester conditions. In this way, Task Controller (an ICT component defined by ISOBUS specification which supervises actively the farming job performed by the tractor) can optimize the whole tractor and implement operational modes to improve the farming job quality and safety of the overall systems. The project started on 1 st April, 2011, and will end the 31 st March, 2013, This paper reports about some achievement gained so far.}, keywords = {agriculture, ICT infrastructure Design, model-driven approach, precision farming, Safety}, isbn = {84-615-9654-4}, author = {Fantuzzi, Cesare and Gutman, Per-Olof and Kaitovi{\'c}, Igor and Larcher, Luca and Marzani, Stefano and Ruggeri, Massimiliano and Zagurskis, Valerijs} } @conference {159.LuVuKaEr12.MELECON, title = {Virtual Metering for Virtual PHEV Aggregation}, booktitle = {Proceedings of the 16th IEEE Mediterranean Electrotechnical Conference (MELECON2012)}, year = {2012}, month = {March 25-28}, address = {Yasmine Hammamet, Tunisia}, abstract = {Technically sustainable solutions for integration of (PH)EVs in Smart Grid emerge as an important concern. We discuss the need for introduction of Virtual Aggregations supported by implementation of Virtual Meters in power system structures. We advocate our proposal with an evaluation of scenarios based on realistic data. The structure and functionalities of the Virtual Aggregator, as well as proposed enhancements on the Smart Grid side, are presented.}, author = {Lukovi{\'c}, Slobodan and Vukmirovi{\'c}, Srdjan and Kaitovi{\'c}, Igor and Erdeljan, Aleksandar} } @conference {150.KaLu11, title = {Adoption of Model-Driven methodology to aggregations design in Power Grid}, booktitle = {INDIN {\textquoteright}11: Proceedings of the 9th IEEE International Conference on Industrial Informatics}, year = {2011}, month = {July 26-29}, pages = {1{\textendash}6}, address = {Caparica, Lisbon, Portugal}, abstract = {Economical and environmental concerns push toward novel solutions for sustainable, renewable and intelligent energy power grid, the Smart Grid. Very often, this includes aggregation of renewable resources and intelligent loads such as electrical vehicles. Such complex system involve a number of various stakeholders coming from different areas of expertise. Even so, on-going projects do not apply unique formal language. In order to better correlate the projects, model-driven methodology and SysML are proposed for system design.}, keywords = {EVs agregation, model-driven design, smart grid, SysML}, doi = {http://dx.doi.org/10.1109/INDIN.2011.6034936}, author = {Kaitovi{\'c}, Igor and Lukovi{\'c}, Slobodan} } @conference {124.LuKaBo10, title = {Adopting system engineering methodology to Virtual Power Systems design flow}, booktitle = {CPSWEEK/GREEMBED 2010: Proceedings of the First Workshop on Green and Smart Embedded System Technology: Infrastructures, Methods and Tools}, year = {2010}, month = {April}, address = {Stockholm, Sweden}, abstract = {The concept of Virtual Power System (VPS) emerges as a promising response for increased concerns on secure, sustainable and at the same time {\textquoteright}clean{\textquoteright} energy supply requests. This novel concept aims at boosting operational efficiency of Distributed Energy Resources (DER) but also at establishing them as an autonomous commercial actor on the open energy market. Nevertheless, VPSs are fairly complex HW/SW systems that require holistic multidisciplinary approach and also novel specification, modeling and analysis instruments to facilitate mutual understanding among stakeholders from different fields. We introduce UML/SysML based modeling methodology to describe such power system related issues aiming at providing an unified modeling instrument applicable for VPSs design flow. In the proposed system engineering methodology, system representation starts from a very general context description and gets refined through different levels of abstraction down to concrete embedded systems employed to perform defined tasks.}, author = {Lukovi{\'c}, Slobodan and Kaitovi{\'c}, Igor and Bondi, Umberto} } @conference {130.LuKaMuBoKuPo10, title = {Functional model of Virtual Power Plant (VPP)}, booktitle = {Proceedings of the 2010 CIGRE (International Council on Large Electric Systems) Session}, year = {2010}, month = {July}, address = {Paris, France}, keywords = {smart grid, unified modeling language (UML), virtual power plants}, author = {Lukovi{\'c}, Slobodan and Kaitovi{\'c}, Igor and Mura, Marcello and Bondi, Umberto and Kuli{\'c}, Filip and Popovi{\'c}, Dragan} } @conference {112.LuKaMuBo10, title = {Virtual Power Plant as a bridge between Distributed Energy Resources and Smart Grid}, booktitle = {Proceedings of 43th Hawaii International Conference on System Sciences (HICSS{\textquoteright}43)}, year = {2010}, month = {January}, address = {Hawaii, USA}, abstract = {The liberalization of energy markets, especially in correlation with the Smart Grid concept development, requires adjusted legislation, new business models, energy stock exchanges establishment and many other advanced instruments. Realization of these features necessitates novel concepts to support such changes in the power system while granting security and reliability of supply. Such evolution poses new challenges to ICT (Information and Communication Technologies) to bridge the gap between increased complexity of deregulated market and on the other side expected rapid growth of number of players in power systems. Increasing presence of Distributed Energy Resources (DER) implementations constitutes a further source of complexity. Bearing in mind ongoing and possible scenarios we aim to determinate the place and role of the novel Virtual Power Plants (VPP) concept, related to the Smart Grid structure. At the same time we introduce an innovative modeling approach as an instrument to determine actors and highlight their actual roles and interactions from different point of view, trying to pave the way for development of a common understanding platform for variety of stakeholders. The effectiveness of the proposed modeling concept is shown through a number of UML models representing system level description of VPP at different levels of abstraction.}, keywords = {distributed energy resources, smart grid, unified modeling language (UML), virtual power plants}, doi = {http://dx.doi.org/10.1109/HICSS.2010.437}, author = {Lukovi{\'c}, Slobodan and Kaitovi{\'c}, Igor and Mura, Marcello and Bondi, Umberto} } @conference {102.LuKaMuBo09, title = {Functional requirements of embedded systems for monitoring and control structure of Virtual Power Plants}, booktitle = {Proceedings of the 2009 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems}, year = {2009}, month = {September}, address = {Crema, Italy}, abstract = {Efficient integration of distributed renewable generation into a reliable single entity in technical and commercial terms is one of key issues for successful realization of smart-grids. The novel concept of Virtual Power Plants (VPP) emerges to be promising response to these needs. ICT is the enabling technology for VPP implementation. In fact, an efficient monitoring and control system coupled with appropriate communication structure must be designed in a scalable and modular way so that full interoperability among components of the system is achieved. On top of that, Control Center applications take care of power flow optimization (production, consumption, ancillary services) and high-level applications (e.g. energy trading, Demand Side Management etc.). In this work we focus on functional requirements for realization of such concept by means of embedded systems.}, keywords = {monitoring and control, system level modeling, virtual power plants}, doi = {http://dx.doi.org/10.1109/EESMS.2009.5341320}, author = {Lukovi{\'c}, Slobodan and Kaitovi{\'c}, Igor and Mura, Marcello and Bondi, Umberto} }