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  • Journal article
    Chang H, Astolfi A, Shim H, 2011,

    A control theoretic approach to malaria immunotherapy with state jumps

    , AUTOMATICA, Vol: 47, Pages: 1271-1277, ISSN: 0005-1098
  • Journal article
    Vinter RB, Bettiol P, 2011,

    Trajectories satisfying a state constraint: improved estimates and new non-degeneracy conditions

    , IEEE Transactions on Automatic Control, Vol: 56, Pages: 1090-1096

    For a state-constrained control system described by a differential inclusion and a single functional inequality state constraint, it is known that, under an `inward pointing condition', the $W^{1,1}$ distance of an arbitrary state trajectory to the set of state trajectories, which have the same left endpoint and which satisfy the state constraint, is linearly related to the state constraint violation. In this paper we show that, in situations where the state-constrained control system is described instead by a controlled differential equation, this estimate can be improved by replacing the $W^{1,1}$ distance on state trajectories by the Ekeland metric of the distance of the control functions. A counter-example reveals that a refinement of this nature is not in general valid for state constrained differential inclusions. Finally we show how the refined estimates may be used to establish new conditions for non-degeneracy of the state constrained Maximum Principle, in circumstances when the data depends discontinuously on the control variable.
  • Journal article
    Laila DS, Lovera M, Astolfi A, 2011,

    A discrete-time observer design for spacecraft attitude determination using an orthogonality-preserving algorithm

    , AUTOMATICA, Vol: 47, Pages: 975-980, ISSN: 0005-1098
  • Journal article
    Ortega R, Praly L, Astolfi A, Lee J, Nam Ket al., 2011,

    Estimation of Rotor Position and Speed of Permanent Magnet Synchronous Motors With Guaranteed Stability

    , IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, Vol: 19, Pages: 601-614, ISSN: 1063-6536
  • Conference paper
    Hey J, Howey DA, Martinez-Botas R, Lamperth Met al., 2011,

    Transient thermal modelling of an Axial Flux Permanent Magnet (AFPM) machine with model parameter optimisation using a Monte Carlo method

    , Vehicle Thermal Management Systems VTMS 10, Publisher: IMechE
  • Journal article
    Norman AK, Kerrigan EC, McKeon BJ, 2011,

    The effect of small-amplitude time-dependent changes to the surface morphology of a sphere

    , JOURNAL OF FLUID MECHANICS, Vol: 675, Pages: 268-296, ISSN: 0022-1120
  • Journal article
    Howey DA, Martinez-Botas RF, Lytton L, Cussons Bet al., 2011,

    Comparative measurements of the energy consumption of 51 electric, hybrid and internal combustion engine vehicles

    , Transportation Research Part D, Vol: 6, Pages: 459-464
  • Journal article
    Couchman IJ, Kerrigan EC, Boehm C, 2011,

    Model reduction of homogeneous-in-the-state bilinear systems with input constraints

    , AUTOMATICA, Vol: 47, Pages: 761-768, ISSN: 0005-1098
  • Journal article
    Pudjianto D, Mancarella P, Gan CK, Strbac Get al., 2011,

    Closed loop price signal based market operation within Microgrids

    , EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Vol: 21, Pages: 1310-1326, ISSN: 1430-144X
  • Journal article
    Schwaegerl C, Tao L, Mancarella P, Strbac Get al., 2011,

    A multi-objective optimization approach for assessment of technical, commercial and environmental performance of microgrids

    , EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Vol: 21, Pages: 1271-1290, ISSN: 1430-144X
  • Journal article
    Parisini T, 2011,

    Untitled

    , IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, Vol: 19, Pages: 245-246, ISSN: 1063-6536
  • Journal article
    Clark JMC, Kountouriotis PA, Vinter RB, 2011,

    A Gaussian Mixture Filter for Range-Only Tracking

    , IEEE TRANSACTIONS ON AUTOMATIC CONTROL, Vol: 56, Pages: 602-613, ISSN: 0018-9286
  • Conference paper
    Jerez J, Constantinides GA, Kerrigan EC, 2011,

    An FPGA Implementation of a Sparse Quadratic Programming Solver for Constrained Predictive Control

    , ACM International Symposium on Field Programmable Gate Arrays, Publisher: ACM
  • Journal article
    Casagrande D, Astolfi A, Ortega R, 2011,

    Asymptotic stabilization of passive systems without damping injection: A sampled integral technique

    , AUTOMATICA, Vol: 47, Pages: 262-271, ISSN: 0005-1098
  • Journal article
    Chaudhuri NR, Chaudhuri B, 2011,

    Damping and Relative Mode-Shape Estimation in Near Real-Time Through Phasor Approach

    , IEEE TRANSACTIONS ON POWER SYSTEMS, Vol: 26, Pages: 364-373, ISSN: 0885-8950
  • Journal article
    Hui SYR, Lin DY, Ng WM, Yan Wet al., 2011,

    A "Class-A2" Ultra-Low-Loss Magnetic Ballast for T5 Fluorescent Lamps-A New Trend for Sustainable Lighting Technology

    , IEEE TRANSACTIONS ON POWER ELECTRONICS, Vol: 26, Pages: 622-629, ISSN: 0885-8993
  • Journal article
    Thambirajah J, Thornhill NF, Pal BC, 2011,

    A Multi­variate Approach Towards Inter-Area Oscillation Damping Estimation Under Ambient Conditions Via Independent Component Analysis And Random Decrement

    , IEEE Transactions on Power Systems, Vol: 26, Pages: 315-322, ISSN: 0885-8950

    This paper presents a novel approach to the monitoring of interarea oscillation frequency and damping using multivariate analysis techniques. A two-step method is presented 1) independent component analysis for the detection of interarea modes and estimation of their frequencies and 2) random decrement for the estimation of mode damping. The method is applied to real measurements taken in Finland within the Nordic Power System to estimate the critical interarea mode frequency and damping in the system.
  • Patent
    Plet CA, Green TC, Walton CM, 2011,

    Electrical Devices With Improved Fault Current Handling Capabilities

    An electrical device comprising: first and second windings that are magnetically coupled such that, during normal operation, magnetic fields of the first and second windings interact and currents flow through the first and second windings; and a power controller arranged to control the current in the second winding in a fault situation, so as to reduce or limit the current magnitude flowing in the first winding or the second winding, or to synchronise the magnetic field of the second winding with the magnetic field of the first winding and thereby reduce their interaction; wherein the second winding incorporates a tap changer arrangement operable to reduce the number of turns in the second winding through which the current in the second winding flows, and thereby decrease the mutual inductance between the first and second windings and reduce the voltage magnitude required of the power controller in order to exercise control in the fault situation.Also provided is a method of operating such a device, and a tap changer arrangement that is well suited for use with such a device
  • Conference paper
    Acha S, Green TC, Shah N, 2011,

    Optimal charging strategies of electric vehicles in the UK power market

    , 2011 IEEE PES Innovative Smart Grid Technologies (ISGT), Publisher: IEEE, Pages: 1-8

    In order to gain the most from their deployment, it is imperative for stakeholders to exploit the main benefits electric vehicles bring to utilities. Therefore, this paper focuses on the aspects required to model the management of electricity supply for electric vehicles. The framework presented details a time coordinated optimal power flow (TCOPF) tool to illustrate the tradeoffs distribution network operators (DNO) might encounter when implementing various load control approaches of electric vehicles. Within an UK context, a case study is performed where the TCOPF tool functions as the intermediary entity that coordinates cost-effective interactions between power markets, network operators, and the plugged vehicles. Results depict the stochastic but optimal charging patterns stakeholders might visualise from electric vehicles in local networks as they are operated to reduce energy and emission costs. Furthermore, results show current emission costs have a negligible weight in the optimisation process when compared to wholesale electricity costs.
  • Book chapter
    Giarré L, Falugi P, Badalamenti R, 2011,

    Hybrid LPV Modeling and Identification

    , Linear Parameter-Varying System Identification New Developments and Trends, Publisher: World Scientific, Pages: 11-39, ISBN: 9789814355452

    This review volume reports the state-of-the-art in Linear Parameter Varying (LPV) system identification.
  • Journal article
    Buchstaller D, Kerrigan EC, Constantinides GA, 2011,

    Sampling and controlling faster than the computational delay

    , IFAC Proceedings Volumes (IFAC-PapersOnline), Vol: 44, Pages: 7523-7528, ISSN: 1474-6670

    For a sampled-data control system, the sampling period is chosen smaller than the computational delay, an approach we call intra-delay sampling. Utilising parallel computing architectures, it is shown that intra-delay sampling schemes are feasible and that they yield better performance than their slower sampling counterparts. © 2011 IFAC.
  • Conference paper
    Boem F, Pellegrino FA, Fenu G, Parisini Tet al., 2011,

    Trajectory clustering by means of Earth Mover's Distance

    , Pages: 4741-4746, ISSN: 1474-6670

    We propose a method for trajectory classification based on a general cluster-based methodology, that can be used both off-line in an unsupervised fashion, both on-line, classifying new trajectories or part of them. We use the Earth Mover's Distance (EMD) and we adapt it in order to employ it as a tool for trajectory clustering. We propose a novel effective method to identify the clusters' representatives by means of the p-median location problem. This methodology is able to manage different length and noisy trajectories and takes velocity profiles and stops into account. We discuss the experimental results and we compare our approach with other trajectory clustering methods. © 2011 IFAC.
  • Journal article
    Boem F, Ferrari RMG, Parisini T, 2011,

    Distributed Fault Detection and Isolation of Continuous-Time Non-Linear Systems

    , EUROPEAN JOURNAL OF CONTROL, Vol: 17, Pages: 603-620, ISSN: 0947-3580
  • Conference paper
    Mayne DQ, Kerrigan EC, Falugi P, 2011,

    Robust model predictive control: Advantages and disadvantages of tube-based methods

    , Pages: 191-196, ISSN: 1474-6670

    An important reason for the success of model predictive control is the fact that, for deterministic systems, feedback and open-loop control are equivalent so that 'optimal' (but implicit) feedback may be obtained by solving an open-loop optimal control problem at each state encountered. This equivalence is not maintained in the presence of uncertainty complicating the development of robust model predictive control. The advantages and limitations of tubebased model predictive control for dealing with uncertainty of various forms are discussed, firstly in the context of constrained linear systems, and an extension to deal with robustness against unstructured uncertainty is briefly described. Tube-based control requires the determination both of a nominal or reference trajectory and an ancillary controller that constrains deviations of the state of the uncertain systems from the nominal trajectory and is difficult to extend to nonlinear systems. A novel ancillary controller for tube-based control of constrained nonlinear systems with additive disturbances that overcomes some disadvantages of a previous version and is relatively simple to implement is described and assessed; the addition of a terminal equality constraint to the nominal optimal control problem and its removal from the ancillary optimal control problem simplifies the analysis, removes some restrictive assumptions, and enables stronger results to be obtained. © 2011 IFAC.
  • Journal article
    Shahzad A, Jones BL, Kerrigan EC, Constantinides GAet al., 2011,

    An efficient algorithm for the solution of a coupled Sylvester equation appearing in descriptor systems

    , Automatica, Vol: 47, Pages: 244-248, ISSN: 1873-2836

    Descriptor systems consisting of a large number of differential-algebraic equations (DAEs) usually arise from the discretization of partial differential-algebraic equations. This paper presents an efficient algorithm for solving the coupled Sylvester equation that arises in converting a system of linear DAEs to ordinary differential equations. A significant computational advantage is obtained by exploiting the structure of the involved matrices. The proposed algorithm removes the need to solve a standard Sylvester equation or to invert a matrix. The improved performance of this new method over existing techniques is demonstrated by comparing the number of floating-point operations and via numerical examples.
  • Journal article
    Angeli D, Kountouriotis PA, 2011,

    Decentralized random control of refrigerator appliances

    , IFAC Proceedings Volumes (IFAC-PapersOnline), Vol: 44, Pages: 12144-12149, ISSN: 1474-6670

    This paper considers the problem of dynamic demand management of domestic refrigerators. Dynamic demand management is a promising research direction, which aims to improve power system resilience, by dynamically controlling the energy consumption of devices that exhibit thermal energy storage. In this approach, the operating temperature of appliances, and thus their energy consumption, is modified dynamically, within a safe range, in response to mains frequency fluctuations. Such an operating scheme aims at reducing the strain that the demand side introduces in a power network, when the corresponding supply is temporarily disrupted. Previous research has highlighted the potential of this idea for responding to sudden power plant outages. However, deterministic control schemes have proved inadequate as individual appliances tend to "synchronize" with each other, leading to unacceptable levels of overshoot in energy demand, when they "recover" their steady-state operating cycles. In this paper we describe random controllers that are able to respond to sudden plant outages and which avoid the instability phenomena associated with other feedback strategies. Stochasticity is used to achieve desynchronization of individual refrigerators while keeping overall power consumption tightly regulated. © 2011 IFAC.
  • Journal article
    Pin G, Parisini T, 2011,

    Networked Predictive Control of Uncertain Constrained Nonlinear Systems: Recursive Feasibility and Input-to-State Stability Analysis

    , IEEE TRANSACTIONS ON AUTOMATIC CONTROL, Vol: 56, Pages: 72-87, ISSN: 0018-9286
  • Journal article
    Chaudhuri NR, Chakraborty D, Chaudhuri B, 2011,

    An Architecture for FACTS Controllers to Deal With Bandwidth-Constrained Communication

    , IEEE TRANSACTIONS ON POWER DELIVERY, Vol: 26, Pages: 188-196, ISSN: 0885-8977
  • Journal article
    Mancarella P, Gan CK, Strbac G, 2011,

    Optimal design of low-voltage distribution networks for CO<sub>2</sub> emission minimisation. Part II: Discrete optimisation of radial networks and comparison with alternative design strategies

    , IET GENERATION TRANSMISSION & DISTRIBUTION, Vol: 5, Pages: 47-56, ISSN: 1751-8687
  • Journal article
    Mancarella P, Gan CK, Strbac G, 2011,

    Optimal design of low-voltage distribution networks for CO<sub>2</sub> emission minimisation. Part I: model formulation and circuit continuous optimisation

    , IET GENERATION TRANSMISSION & DISTRIBUTION, Vol: 5, Pages: 38-46, ISSN: 1751-8687

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