Doctor of Philosophy / Electrical and Computer Engineering / Balasubramaniam Natarajan / A cyber-physical system (CPS) typically consists of networked computational elements that control physical processes. As an integral part of CPS, the widespread deployment of communicable sensors makes the task of monitoring and control quite challenging especially from the viewpoint of scalability and complexity. This research investigates two unique aspects of overcoming such barriers, making a CPS more robust against data explosion and network vulnerabilities. First, the correlated characteristics of high-resolution sensor data are exploited to significantly reduce the fused data volume. Specifically, spatial, temporal and spatiotemporal compressed sensing approaches are applied to sample the measurements in compressed form. Such aggregation can directly be used in centralized static state estimation even for a nonlinear system. This approach results in a remarkable reduction in communication overhead as well as memory/storage requirement. Secondly, an agent based architecture is proposed, where the communicable sensors (identified as agents) also perform local information processing. Based on the local and underdetermined observation space, each agent can monitor only a specific subset of global CPS states, necessitating neighborhood information exchange. In this framework, we propose an agent based static state estimation encompassing local consensus and least square solution. Necessary bounds for the consensus weights are obtained through the maximum eigenvalue based convergence analysis and are verified for a radial power distribution network. The agent based formulation is also applied for a linear dynamical system and the consensus approach is found to exhibit better and more robust performance compared to a diffusion filter. The agent based Kalman consensus filter (AKCF) is further investigated, when the agents can choose between measurements and/or consensus, allowing the economic allocation of sensing and communication tasks as well as the temporary omission of faulty agents. The filter stability is guaranteed by deriving necessary consensus bounds through Lyapunov stability analysis. The states dynamically estimated from AKCF can be used for state-feedback control in a model predictive fashion. The effect of lossy communication is investigated and critical bounds on the link failure rate and the degree of consensus that ensure stability of the agent based control are derived and verified via simulations.

abstract: Lighting systems and air-conditioning systems are two of the largest energy consuming end-uses in buildings. Lighting control in smart buildings and homes can be automated by having computer controlled lights and window blinds along with illumination sensors that are distributed in the building, while temperature control can be automated by having computer controlled air-conditioning systems. However, programming actuators in a large-scale environment for buildings and homes can be time consuming and expensive. This dissertation presents an approach that algorithmically sets up the control system that can automate any building without requiring custom programming. This is achieved by imbibing the system self calibrating and self learning abilities. For lighting control, the dissertation describes how the problem is non-deterministic polynomial-time hard(NP-Hard) but can be resolved by heuristics. The resulting system controls blinds to ensure uniform lighting and also adds artificial illumination to ensure light coverage remains adequate at all times of the day, while adjusting for weather and seasons. In the absence of daylight, the system resorts to artificial lighting. For temperature control, the dissertation describes how the temperature control problem is modeled using convex quadratic programming. The impact of every air conditioner on each sensor at a particular time is learnt using a linear regression model. The resulting system controls air-conditioning equipments to ensure the maintenance of user comfort and low cost of energy consumptions. The system can be deployed in large scale environments. It can accept multiple target setpoints at a time, which improves the flexibility and efficiency of cooling systems requiring temperature control. The methods proposed work as generic control algorithms and are not preprogrammed for a particular place or building. The feasibility, adaptivity and scalability features of the system have been validated through various actual and simulated experiments. / Dissertation/Thesis / Doctoral Dissertation Computer Science 2015

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-05-04T17:30:47Z No. of bitstreams: 1 ALDENOR FALCÃO MARTINS – DISSERTAÇÃO (PPGEE) 2015.pdf: 15602466 bytes, checksum: 608173ca67ff68da8ae45b321aa82204 (MD5) / Made available in DSpace on 2018-05-04T17:30:47Z (GMT). No. of bitstreams: 1 ALDENOR FALCÃO MARTINS – DISSERTAÇÃO (PPGEE) 2015.pdf: 15602466 bytes, checksum: 608173ca67ff68da8ae45b321aa82204 (MD5) Previous issue date: 2015-04-24 / Segundo o IBGE em 2013, o Brasil apresentava 13% de sua população composta por pessoas acima de 65 anos, somado a isto, o estilo de vida das sociedades ocidentais tem facilitado o aparecimento de doenças crônicas cada vez mais cedo. A premissa é que tornemos mais eficiente a utilização do nosso sistema de saúde, pois este é um recurso escasso. Uma forma de melhorar esta eficiência é assegurar que os tratamentos prescritos serão devidamente seguidos. Quando o paciente se encontra no hospital uma gama de recursos monitora a saúde do paciente oferecendo acompanhamento seguro na eventualidade de um desvio, alertando e armazenando as informações do paciente no decorrer de suas atividades. Um recurso que ajuda no acompanhamento deste paciente é a monitoração remota do paciente, que possibilita que sensores enviem a informação da condição de saúde do paciente e permitam o acompanhamento do mesmo. Sistemas Físicos Cibernéticos (SFC) são entidades computacionais ligadas em rede que operam entidades no mundo físico de maneira cooperativa. Tais sistemas podem ser utilizados em redes de monitoramento remoto de pacientes com o fim de apresentar e ajustar o tratamento de acordo com as recomendações do médico. Este trabalho propõe um passo na direção da autonomia, que permita uma melhor qualidade de vida ao paciente crônico, permitindo que situações conhecidas e dentro de um regime de segurança previamente determinado pelo médico sejam ajustadas. Este trabalho apresenta uma proposta de um Sistema Físico Cibernético (SFC), que permite que adequações ao tratamento previamente elaboradas sejam colocadas em planos de tratamento por meio de agentes inteligentes e de planejadores SAT e sejam disponibilizadas de acordo com a mudança da condição do paciente, através de uma rede monitoramento do paciente, seguindo padrões estabelecidos para dispositivos médicos utilizados em casa que disponibiliza o tratamento ao paciente. O modelo proposto é indicado para o acompanhamento em casa de doenças crônicas através de um coletor central responsável pela coordenação do acompanhamento do paciente. / According to IBGE in 2013 13% of the population had 60 or more years old. As the national population ages, we have to move towards more efficient use of SUS. A way to improve is the closer followup of patient’s evolution by the healthcare professional. At the hospital the patient has access to a set of equipments and expert knowledge capable to correct the treatment path. From this scenario it is easy to imply the need for a change, the current status quo is unbearable financially and cumbersome for patient and doctor routines. A resource that helps is the remote patient monitoring (RPM) , where sensors provide the latest information about patient’s health status and are able to suggest a course correction on the treatment path. A Cyber-Physical System (CPS) is a network of interacting computational entities with physical inputs and outputs that work together towards a goal. A CPS can be part of a RPM in order to present and adjust the treatment according to the healthcare professional recommendations. This work offers a framework for situations where the medical expert knowledge is complete allowing changes on the treatment path be adjusted with minimum risk. Our proposal to deal with the problem is a CPS based remote patient monitoring network where a model for the system is developed based on Multiagent Agent System (MAS) and automatic planning system based on SAT, allowing safe and minimal course correction on treatment paths already set for a patient. This proposal operates through a central hub element responsible to coordinate the followup of the patient.

abstract: With growing complexity of power grid interconnections, power systems may become increasingly vulnerable to low frequency oscillations (especially inter-area oscillations) and dependent on stabilizing controls using either local signals or wide-area signals to provide adequate damping. In recent years, the ability and potential to use wide-area signals for control purposes has increased since a significant investment has been made in the U. S. in deploying synchrophasor measurement technology. Fast and reliable communication systems are essential to enable the use of wide-area signals in controls. If wide-area signals find increased applicability in controls the security and reliability of power systems could be vulnerable to disruptions in communication systems. Even though numerous modern techniques have been developed to lower the probability of communication errors, communication networks cannot be designed to be always reliable. Given this background the motivation of this work is to build resiliency in the power grid controls to respond to failures in the communication network when wide-area control signals are used. In addition, this work also deals with the delay uncertainty associated with the wide-area signal transmission. In order to counteract the negative impact of communication failures on control effectiveness, two approaches are proposed and both approaches are motivated by considering the use of a robustly designed supplementary damping control (SDC) framework associated with a static VAr compensator (SVC). When there is no communication failure, the designed controller guarantees enhanced improvement in damping performance. When the wide-area signal in use is lost due to a communication failure, however, the resilient control provides the required damping of the inter-area oscillations by either utilizing another wide-area measurement through a healthy communication route or by simply utilizing an appropriate local control signal. Simulation results prove that with either of the proposed controls included, the system is stabilized regardless of communication failures, and thereby the reliability and sustainability of power systems is improved. The proposed approaches can be extended without loss of generality to the design of any resilient controller in cyber-physical engineering systems. / Dissertation/Thesis / Ph.D. Electrical Engineering 2014

The modern smart grid would involve deep integration between measurement nodes, communication systems, artificial intelligence, power electronics and distributed resources. On one hand, this type of integration can dramatically improve the grid performance and efficiency, but on the other, it can also introduce new types of vulnerabilities to the grid. To obtain the best performance, while minimizing the risk of vulnerabilities, the physical power system must be designed as a security aware system. In this dissertation, an interoperability and communication framework for microgrid control and Cyber Physical system enhancements is designed and implemented taking into account cyber and physical security aspects. The proposed data-centric interoperability layer provides a common data bus and a resilient control network for seamless integration of distributed energy resources. In addition, a synchronized measurement network and advanced metering infrastructure were developed to provide real-time monitoring for active distribution networks. A hybrid hardware/software testbed environment was developed to represent the smart grid as a cyber-physical system through hardware and software in the loop simulation methods. In addition it provides a flexible interface for remote integration and experimentation of attack scenarios. The work in this dissertation utilizes communication technologies to enhance the performance of the DC microgrids and distribution networks by extending the application of the GPS synchronization to the DC Networks. GPS synchronization allows the operation of distributed DC-DC converters as an interleaved converters system. Along with the GPS synchronization, carrier extraction synchronization technique was developed to improve the system’s security and reliability in the case of GPS signal spoofing or jamming. To improve the integration of the microgrid with the utility system, new synchronization and islanding detection algorithms were developed. The developed algorithms overcome the problem of SCADA and PMU based islanding detection methods such as communication failure and frequency stability. In addition, a real-time energy management system with online optimization was developed to manage the energy resources within the microgrid. The security and privacy were also addressed in both the cyber and physical levels. For the physical design, two techniques were developed to address the physical privacy issues by changing the current and electromagnetic signature. For the cyber level, a security mechanism for IEC 61850 GOOSE messages was developed to address the security shortcomings in the standard.

The thesis reviews the current situation related to the Industry 4.0 and puts it into context. In the first part of the thesis, there is an introduction to the current economic situation and the major challenges. The concept and vision of Industry 4.0 is introduced together with the world's leading initiatives and examples of Industry 4.0 technologies in manufacturing processes presented by tech leaders. The thesis also includes examples of readiness models and simulated calculation ROCE. The finding of the thesis is that, although the very concept of Industry 4.0 is not well known, digitization and automation of production continues and both are considered a necessity. Interviews with experts from the business practice in the Czech Republic introduces key opportunities and challenges arising from new technologies and when they might become the new standard.

A need for a cost effective, versatile and easy to use suspension component testing method has arisen, following the development of a four-state hydro-pneumatic semi-active spring-damper system. A method known as hardware-in-the-loop (HiL) was investigated, in particular its use and compatibility with tests involving physical systems – previously HiL was used predominantly for Electronic Control Unit (ECU) testing. The suitability of HiL in the development of advanced suspension systems and their control systems, during which various vehicle models can be used, was determined. A first step in vehicle suspension design is estimating a desired spring and damper characteristic, and verifying that characteristic using software simulation. The models used during this step are usually low-order, simple models, which hampers quick development progress. To predict vehicle response before vehicle prototype completion, many researchers have attempted to use complex and advanced damper models to simulate the vehicle’s dynamics, but these models all suffer from some drawback – it is either based on empirical data, giving no indication of the physical parameters of the design sought; it may be overly complex, having many parameters and thus rendering software impractical; or it may be quick but based on the premise that there is no hysteresis in the damping character. It can be seen that an obvious answer exists – use a physical commercially available or prototype damper in the software simulation instead of the mathematical model. In this way the suspension deflection, i.e. the true motion of the damper is used as excitation, and the true damper force is measured using a hydraulic actuator and load cell. The vehicle mass motions are simulated in a software environment. This is basically what HiL simulation does. The HiL method was verified by comparing HiL simulations and tests to globally accepted testing methods, employing widely-used vehicle models: linear single-degree-of-freedom (SDOF) and two-degrees-of-freedom (2DOF) or quarter-car models were used. The HiL method was also compared to a non-linear physical system to verify that the method holds for real vehicle suspension geometries. This meant that HiL had to perform adequately at both ends of the suspension-testing spectrum – base software and real system simulation. The comparison of the HiL and software/real system simulation was done using the “Error Coefficient of Variance” (ECOV) between the compared signals; this quantitative measure proved very sensitive and performed dubiously in the presence of signal offsets, phase lags and scaling errors, but remains a tangible, measurable parameter with which to compare signals. Visual confirmation was also obtained to back the ECOV values. It was found that even using a relatively low-force actuator, the HiL simulation results followed the software/real system responses well. Phase lags and DC offsets in the HiL simulation’s measured signals (as well as the real systems responses) has an adverse effect on the performance of the HiL simulation. Special attention must thus be paid to the zeroing of equipment and the amount/type of filters in the system, as these affect the HiL results dramatically. In all, HiL was proven to be a versatile and easy to use alternative to conventional mass-based suspension testing. / Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2006. / Mechanical and Aeronautical Engineering / unrestricted

This thesis describes the implementation of a Digital Twin tied to Virtual Reality environment thatcould, by easy means be expanded to Augmented Reality-solution. The field is of interest due to thefact that movement into Industry 4.0 puts the traditional operator in a new seat of work. Previoushands-on tasks are replaced with system monitoring and supervision roles. New interconnectedindustrial hardware allows for extensive data collection, while interactive technology like VR/ARhelps monitoring live systems in completely new manners. An operator can overview and debugindustrial systems while not even being in close proximity of the physical system. This provides theopportunity to increase the level of system information presented to the operator. The Cyber PhysicalFactory created by Festo was targeted to be represented as a digital twin. The question asked: What arethe advantages and/or disadvantages of monitoring and troubleshooting a Festo CP-Factory by meansof a digital twin-driven visualization? proved to be extensive and the work included mapping ofimportant factory data and DRM-research to find visual improvements between the provided solutionsby Festo, and an implemented digital twin. The solution we produced focuses on overview anddebugging and it connects to OPC-servers on each mapped module of the Cyber Physical Factory andacquires the data. This data can then be used to expand, test and debug previous sessions. Each realimplementation of a factory has some type of logging of data, our solution allows visualization of thoselog entries as close to reality as possible, reducing the need to search databases for indications ofproblems. The Unity 3D created software also handles dynamic connections where the operator canmodify which nodes to connect to in an intuitive way, this enables our software to abstract and modifyinformation outside of the source code.

<p>Due to the rapid development of wireless communication and network technology, more and more wireless devices (e.g., Siemens, Lutron, etc.) are used in residential and commercial buildings. The wireless system has many advantages that traditional wired-based systems do not have, such as time-saving deployment and easy maintenance. However, the wireless system is also vulnerable to cyber-attacks since the data packets are transmitted by radio waves rather than by physical medium. The current cyber detection system (e.g., Intrusion detection system) monitors the data traffic to identify the anomalies in the network. However, it is unable to detect the attacks that tamper with the control logic or operating parameters, which results in the malfunction of the system. This thesis developed an integrated, cyber-security framework for cyber-attack detection in smart buildings.</p> <p>The objective of this research is to develop an integrated cyber-security framework for wireless-based smart building systems to protect buildings from the cyber-attacks. The wireless-based smart building systems are operated and controlled by either a two-position or continuous controlled approach. The efforts in this study have developed a cyber-security framework to deal with both two-position control and continuous control. For the two-position controlled smart buildings, the developed cyber-security framework integrates the data and models of both cyber and physical domains of building systems to detect faults, abnormal operations, and cyber attacks. The cyber-security framework developed for the continuous controlled system combines a data-driven model for detecting the faults of sensor measurements and a physical model based on engineering principle (e.g., laws of thermodynamics or control logic) to detect the anomaly of system operation.</p> <p>To develop the cyber-security frameworks, the testbeds corresponding to the two-position and continuous wireless systems were constructed for attack-oriented tests. A wireless-based lighting system for smart homes was used as the testbed for the study of the two-position control. It has a wireless occupancy sensor, an actuator for the light switch, and an open-source operating platform (OpenHAB) for system control and monitor. The platform of the wireless is the ZigBee. An indoor shading system at a living lab in new Herrick building at Purdue University was utilized as the testbed for the study of the continuous controlled system. The indoor shading system exploits the roller shades to block the excess daylighting to provide an acceptable illuminance condition for occupants. The shading system uses the wireless illuminance sensor, weather condition, and wire-based controller to automatically operate the shades for the acceptable illuminance. </p> <p>The study implemented designed cyber-attacks to validate the effectiveness of the developed frameworks. The final results show that the developed two models were able to detect the attacks effectively (95-100% attacks identified and isolated). The abnormal operations tested in two-position control system were identified when an abnormal state was triggered, or the modelled state and real state did not match in the finite state machine model developed. For continuous control, the abnormal operations were detected when there is a significant deviation between the modelled measurement and the actual measurement. The cybersecurity framework developed in the thesis demonstrates an effective approach for detecting system faults caused by attacks. The frameworks could be widely used for other different building systems and beyond buildings, such as transportation or industrial manufacturing systems.</p>

Les travaux menés dans cette thèse de doctorat s’inscrivent dans le cadre d’un effort pluslarge d’automatisation des systèmes de simulation industriels. Dans l’industrie aéronautique,et plus particulièrement au sein d’Airbus, l’application historique de la simulation est laformation des pilotes. Il existe aussi des utilisations plus récentes dans la conception desystèmes, ainsi que dans l’intégration de ces systèmes. Ces dernières utilisations exigent untrès haut degré de représentativité, là où historiquement le plus important était le ressenti dupilote. Les systèmes sont aujourd’hui divisés en plusieurs sous-systèmes qui sont conçus, implémentéset validés indépendamment, afin de maintenir leur contrôle malgré l’augmentationde leurs complexités et la réduction des temps de mise sur le marché. Airbus maîtrise déjà lasimulation de ces sous-systèmes, ainsi que leurs intégrations en simulation. Cettemaîtriseest empirique, les spécialistes de la simulation reprennent l’ordonnancement d’intégrationsprécédentes, et l’adaptent à une nouvelle intégration. C’est un processus qui peut parfois êtrechronophage, et qui peut introduire des erreurs. Les tendances actuelles de l’industrie sont à la flexibilité des moyens de production, àl’intégration d’outils logistiques permettant le suivi, à l’utilisation d’outils de simulation enproduction, et à l’optimisation des ressources. Les produits sont de plus en plus souvent desitérations d’anciens produits améliorés, et les tests et simulations intégrés à leurs cycles de vie.Travailler de manière empirique dans une industrie qui nécessite de la flexibilité estune contrainte, et il est aujourd’hui important de facilement modifier des simulations. Laproblématique est donc de mettre en place des méthodes et outils permettant a priori degénérer des ordonnancements de simulations représentatifs.Afin de répondre à ce problème, nous avons mis en place une méthode permettant de décrireles composants d’une simulation, la manière dont cette simulation pourra être exécutée,ainsi que des fonctions permettant de générer des ordonnancements. Par la suite, nous avonsimplémenté un outil afin d’automatiser la recherche d’ordonnancement, en se basant sur desheuristiques. Enfin nous avons testé et vérifié notre méthode et outils sur des cas d’étudesacadémiques et industriels. / The work carried out in this Ph.D. thesis is part of a broader effort to automate industrialsimulation systems. In the aeronautics industry, and more especially within Airbus, thehistorical application of simulation is pilot training. There are also more recent uses in thedesign of systems, as well as in the integration of these systems. These latter applicationsrequire a very high degree of representativeness, where historically the most important factorhas been the pilot’s feeling. Systems are now divided into several subsystems that are designed, implemented andvalidated independently, in order tomaintain their control despite the increase in their complexity,and the reduction in time-to-market. Airbus already has expertise in the simulationof these subsystems, as well as their integration into a simulation. This expertise is empirical;simulation specialists use the previous integrations schedulings and adapt it to a newintegration. This is a process that can sometimes be time-consuming and can introduce errors.The current trends in the industry are towards flexible production methods, integrationof logistics tools for tracking, use of simulation tools in production, as well as resourcesoptimization. Products are increasingly iterations of older, improved products, and tests andsimulations are increasingly integrated into their life cycles. Working empirically in an industry that requires flexibility is a constraint, and nowadays itis essential to facilitate the modification of simulations. The problem is, therefore, to set upmethods and tools allowing a priori to generate representative simulation schedules.In order to solve this problem, we have developed a method to describe the elementsof a simulation, as well as how this simulation can be executed, and functions to generateschedules. Subsequently, we implemented a tool to automate the scheduling search, based onheuristics. Finally, we tested and verified our method and tools in academic and industrialcase studies.