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Energy management and savings in residential homes are emerging concerns nowadays because of several challenges facing the energy sector such as energy sources limitations and environmental impacts. Non-intrusive load monitoring (NILM) was introduced as a set of methods and techniques that aim to decompose the total aggregate consumption measured by the smart meter into the consumptions by individual appliances present in the household. The detailed information on energy usage for each device were found to be a good influencing method for the residents to adopt better devices usage profiles which lead eventually to noticeable energy savings. Recent research had shown that the Hidden Markov Models (HMMs) and its extensions are effective models in the load disaggregation problem. The authors had introduced a new unsupervised approach for load disaggregation that includes the mutual devices interactions information into the Factorial Hidden Markov Model (FHMM) representation of the aggregate signal in an earlier work. In this paper, we introduce an adaptive approach for estimating devices main power consumptions and their two-way interactions during the disaggregation process. The adaptive approach is used to mimic the changes in devices consumptions and two-way interactions. The adaptive estimation process was carried out only for cases when there are four devices or less that are operating/ON instantaneously. The proposed approach was tested with data from the REDD public data set and it showed better performance in terms of energy disaggregation accuracy compared with the standard FHMM. The adaptive estimating of main factors effects (primary power consumptions) and two-way interactions during the disaggregation process provided higher disaggregation accuracy results, in general, than those with fixed factors and two-way interactions values.

Non-intrusive load monitoring (NILM) is a set of techniques that aims to decompose the aggregate energy consumptions of a household into the energy consumed by the respective individual appliances. When some of the home appliances have power consumptions levels that overlap with each other, it becomes a challenging problem to disaggregate the energy consumed by each of these appliances. In this work, we present an approach that split the clusters of the overlapping energy consumptions into the respective energy consumed by the individual appliances. The proposed approach involves firstly to analyze the cohesion of devices clusters to determine if a cluster should be split into two clusters. The proposed cluster splitting approach was tested on cases of overlapping devices clusters from six real houses available from the REDD public data sets. The results showed that the performance of the proposed approach depends on the degree of overlapping of the devices clusters, on whether the clusters are tight or loose and on the sizes of the clusters. The proposed approach can be applied to a clustering-based load disaggregation method as a subsequent step to deal with situations of overlapping appliances consumptions, so as to improve the overall energy disaggregation accuracy. Accepted version

Energy savings and energy management are some of the important considerations in the deployment of smart grids. Non-intrusive load monitoring (NILM) is a set of methodologies and techniques that analyze the total aggregated smart meter measurements and break them down into the individual consumptions by devices present in a household. Through NILM, the household owners will be informed about detailed consumptions by individual devices and this information was found to be influencing their energy consumption behavior, resulting in energy savings. In this work, we focus on a specific challenge in the NILM realm, which is disaggregating appliances with close or overlapping power consumptions. An approach for devices clusters splitting is proposed based on testing clusters cohesion. The proposed approach was tested on a real house from the REDD public data set. The performance of the proposed approach was found to be dependent on clusters tightness, size and degree of overlapping.

Energy savings is one of the hottest issues and concerns nowadays due to high oil prices and global warming as a result of CO2 emissions. Non-intrusive appliances load monitoring (NIALM) is a methodology that aim to breakdown the total power consumption measured by the smart meter in each household into the power consumed by the individual appliances. These detailed information on individual appliances consumptions can influence the users to follow better energy usage profiles so as to achieve energy savings. We introduce a novel energy disaggregation model that consider mutual devices interactions and embed the information on devices interactions into the Factorial Hidden Markov Models (FHMM) representations of the aggregated data. The hidden states in the FHMM were inferred by means of the Viterbi algorithm. Devices interactions is a power quality issue that affects the measured power consumed by a device when there are other devices connected to the network. We tested our model using 16 a selected house from the REDD public data set. Our proposed approach showed enhanced results when compared with the standard FHMM. Devices interactions, when observed, enabled us to disaggregate and assign energy consumption for individual devices more accurately Accepted version

In the chain scattering framework, it has been shown in Lee and Soh (2004) that the problem of simultaneous stabilization of a finite collection of l linear time-invariant plants such that each closed-loop transfer function has an norm less than a prescribed performance level is equivalent to a simultaneous strongly stabilizing problem, i.e. finding a single stable and norm bounded controller for associated l − 1 unimodular plants such that each resulting closed-loop system is stable and norm bounded. This paper attempts to provide a solution to the simultaneous strongly stabilization problem. A new sufficient condition in the form of the solution to only one algebraic Riccati equation is provided for the existence of a strongly stabilizing controller for a given stable system obtained from the parameterization of stabilizing controllers. With the parameterization of strongly stabilizing controllers provided in this paper, a solution is given for the simultaneous strongly stabilization problem and hence, ...

The chain scattering approach to the solution of the linear time-invariant (LTI) H infinity control problem proposed in Kimura (1995) is extended to the linear time-varying (LTV) case in this paper. A proof of sufficiency and necessity for (Jmr,Jpr)-lossless and co-(Jmq, Jmr)-lossless factorizations for the solvability of the four-block LTV Hinfinity control problem is shown. The solutions obtained exist in the form of Lyapunov stabilizing solutions to two matrix Riccati differential equations and satisfy a spectral radius coupling condition. A state space proof is also given for the LTVco-(Jmq, Jmr)-lossless embedding theorem in Hinfinity by exploiting the cascade structure of the dual chain scattering formalism and the structural decomposition of the system.

) ) ( ( J J J J Using the notions of,-lossless conjugations and,-lossless factorizations, H the one and two-block linear time-varying infinite horizon standard control problem is solved by means of the chain scattering formalism in this paper. The solutions are shown to exist in the form of non-negative definite Lyapunov stabilizing solutions to two matrix differential Riccati equations and satisfying a spectral radius coupling condition. In addition, a state-space proof of the crucial timeJ H varying-lossless embedding theorem in is also shown by exploiting the cascading structure of the chain scattering formalism and with the standard assump) ( J J tions on the plant, a proof of necessity of,-lossless factorization is also given H for the solvability of the control problem.

This paper proposes a system for the monitoring and data acquisition of information that are associated with the energy consumed by an equipment or facility. The acquired data are stored in a relational database and can be retrieved for further processing and analysis by the energy management personnel. Various scheduler functions can be carried out to ease the tasks of energy management for the facility. The proposed system is integrated with a programmable logic controller for the monitoring and control of equipment. The status of the equipment are displayed through a SCADA platform to provide a visual interface for the operator. Through the mobile phone's Short Message Service (SMS) function, an online condition-based maintenance monitoring alert function is provided. Alarm signals from faulty equipment or plant malfunctions and command signals as SMS messages sent by the user is routed through the system and the PLC, thereby allowing remote communications among the equipment and the user.

A simultaneous reliable Hinfin stabilization of a finite collection of linear-time-invariant plants using a two-controller configuration is discussed in this paper. A systematic design procedure is proposed that guarantees Hinfin performance and closed-loop stability when both controllers are in normal operations or when either one of them fails.

The strongly H/sup /spl infin// stabilization problem is the problem of finding a strictly bounded real controller such that the resulting closed-loop transfer function is also strictly bounded real. Such problems can arise as equivalent problems in the simultaneous stabilization of two or more plants by a single controller such that each closed-loop transfer function has a H/sup /spl infin// norm less than a given performance level. We present a condition in the form of solutions to two AREs to solve the strongly H/sup /spl infin// stabilization problem.

The notion of conjugation (Kimura 1989 b) is extended to finite-dimensional linear time-varying systems in this paper. In addition, we derive the necessary and suffiJ J cient conditions for the existence of stabilizing-lossless conjugators and-lossless factorizations of linear time-varying systems. These conditions are shown to exist in the form of a non-negative definite Lyapunov stabilizing solution to a matrix differential Riccati equation. It extends the linear time-invariant results developed by Kimura (1989 b, 1992) to the time-varying case.

The notion of co-conjugation for linear time-varying (LTV) systems is introduced. Via the dual chain scattering formalism, we derive the state-space characterizations for an exponential dichotomous co-lossless and co-( J, J )-lossless uniform LTV mq mr system and the inequality condition for the associated bounded I/O operators. Uniform time-varying realizations are considered, as they are required for the proof of the necessity of the state-space characterizations. The fundamental operation of co-( J, J )-lossless conjugation is shown to provide a simple way to the co mq mr ( J, J )-lossless factorizations of LTV systems, where necessary and sufficient mq mr conditions for its existence are given.