1,720,956 research outputs found
Battery internal state estimation using a mixed Kalman cubature filter
No full textBatteries are extensively used as small to medium range energy storage devices in smart grids. The estimation of the internal states of the batteries such as state-of-charge (SoC) is critical to provide consistent and efficient energy storage capabilities for the grids. In general, the electrochemical batteries are represented by non-linear mathematical models. Hence, the non-linear filters such as the extended Kalman filter (EKF), cubature Kalman filter (CKF) and particle filters are widely used for the battery state estimation. However, the non-linear filters are complex compared to the linear filters such as the Kalman filter. The non-linear battery model considered in this paper has an inherent linear sub structure. Hence, we propose a mixed Kalman cubature filter to exploit the inherent linearity to achieve better estimation results with a decreased complexity. The proposed filter uses the Kalman filter and the 3rd degree spherical radial cubature rule to calculate the first and second order moments of the linear and non-linear components, respectively, and subsequently, to estimate the SoC of the batteries. The experimental results show that the proposed filter performs better than the EKF and CKF. Further, the computational complexity of the proposed filter is less than the computational complexity of the CKF. Under the chosen conditions, the proposed filter achieves the average mean square error of approximately 1.1% where as the CKF and EKF achieves 1.3% and 1.5%, respectively with the maximum SoC
Appliance load disaggregation based on maximum a-posterior particle filter (MAP-PF)
No full textA fine-grained and real-time energy data provided by the smart meters is one of the main facilitators for achieving improved energy efficiency in future smart grids. Further disaggregating the information provided by smart meters into energy consumption of individual appliances, often referred as appliance load disaggregation (ALD), can provide valuable information. In this paper, we propose a non-intrusive ALD based on the maximum a-posterior particle filter (MAP-PF). The proposed non-intrusive ALD allows to identify state of an appliance by utilizing the probabilistic appliance models and the aggregated power of the household, measured by a single smart meter. A combination of multi-state appliances modeled by hidden Markov models and the corresponding aggregated power is modeled by a factorial hidden Markov model (FHMM). The FHMM models the household as a finite state machine with discrete states. The proposed MAP-PF based ALD uses the principles of particle filter to infer the maximum probable state of the household and subsequently, the state of each appliance at a given time under the Viterbi framework. Furthermore, we evaluated the proposed method using a simulated and well known real-world data sets in comparison with the PF based ALD. In our simulation results, the proposed method achieves similar or higher estimation accuracy with significantly less computational complexity compared to the PF based ALD method
Distributed object tracking based on information weighted uav selection with priory objects
No full textIn this work, we propose a distributed cubature information filter based multi-object tracking method with an information weighted selection for unmanned aerial vehicle (UAV) networks. In an UAV network, multiple UAVs can observe multiple objects in the region of interest. Further, the UAVs can exchange the objects local information among themselves and fuse them together to obtain the global state of the objects. As the number of UAVs in the network increases, the information exchange among the UAVs suffers from scalability, bandwidth and energy limitations. Thus, it is usually desirable to allow only a desired number of UAVs with highly relevant information to participate in the information exchange. In our approach, the innovation vector within the information filtering framework is used to calculate the amount of information associated with each UAV. Further, a threshold based selection mechanism is proposed to facilitate the UAVs to take independent decisions on whether to participate in the information exchange or not. In the proposed method, the UAVs take the decision to participate in the information exchange based on the information associated with a dynamic subset of objects known as priory objects while keeping the total number of information exchanges in the network to a desired number (on average)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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