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Prosumers’ Business Models in Future Electricity Markets; Peer to Peer, Community Self Consumption, and Transactive Energy Models
No full textThis paper discusses prosumers’ business models in future electricity markets. In this view, the goal is to analyse the dimensions which peer-to-peer, community self-consumption, and transactive energy models add to the traditional electricity market. They enable prosumers to play an active role and require them to acquire appropriate business models. Definitions of the three models, their domains, potential contradictions, and alignments are systematically reviewed. Furthermore, the importance of prosumers’ preferences on their business models are discussed. In doing so, the paper can yield insights into prosumers’ role in future electricity markets
Fast Sparsity-Assisted Signal Decomposition with Non-Convex Enhancement for Bearing Fault Diagnosis
No full textSparsity-assisted signal decomposition based on morphological component analysis (MCA) for bearing fault diagnosis has been studied in depth. However, existing algorithms often use different combinations of representation dictionaries and priors, leading to difficult dictionary choice and high computational complexity. This paper aims to develop a fast sparsity-assisted algorithm to decompose a vibration signal into discrete frequency and impulse components for bearing fault diagnosis. We introduce the morphological discrimination of discrete frequency and impulse components in time and frequency domains respectively for the first time. To use this morphological discrimination, we establish a fast sparsity-assisted signal decomposition (SASD) based on MCA with non-convex enhancement. We further prove the necessary and sufficient condition to guarantee the convexity and use the majorization minimization (MM) algorithm to derive a fast solver. The proposed algorithm not only has low computational complexity, but also avoids choosing multiple dictionaries as well as underestimation of impulse features. Furthermore, an adaptive parameter selection algorithm to set parameters of our algorithm is designed for real applications. The effectiveness of fast SASD and its adaptive variant is verified by both simulation studies and bearing diagnosis cases
Channel Estimation of IRS-Aided Communication Systems with Hybrid Multiobjective optimization
No full textIn this paper, we propose a compressive channel estimation techniques for IRS-assisted mmWave multi-input and multi-output (MIMO) system. To reduce the training overhead, the inherent sparsity in mmWave channels is exploited. By utilizing the properties of Kronecker products, IRS-assisted mmWave channel estimation are converted into a sparse signal recovery problem, which involves two competing cost function terms (measurement error and a sparsity term). Existing sparse recovery algorithms solve the combined contradictory objectives function using a regularization parameter, which leads to a suboptimal solution. To address this concern, a hybrid multiobjective evolutionary paradigm is developed to solve the sparse recovery problem, which can overcome the difficulty in the choice of regularization parameter value. Simulation results show that under a wide range of simulation settings, the proposed algorithm achieves competitive error performance compared to existing channel estimation algorithms
Additive Omnichannel Atmospheric Cues:The Mediating Effects of Cognitive and Affective Responses on Purchase Intention
No full textIn today’s channel-centric retail ecosystem the right mix and orchestration of online and offline stimulus is paramount towards providing an optimal store atmosphere and shopping experience. Applying the S-O-R framework, this research explores additive omnichannel atmospheric cues stimuli, in order to discover their impact on affective (i.e., pleasure, arousal and dominance) and cognitive (i.e., store environmental quality perception) states and their consequential effect on consumer responses in the form of purchase intention. Employing a four-condition repeated measures experimental design in a physical store, utilizing mobile, IoT and social media channels (Study 1), as well as a between-subjects online lab experiment (Study 2), this research sheds light into the affective and cognition-mediated causal mechanisms that influence shopping outcomes. This work reveals that combining stimulus from all retail channels within the physical store (i.e., omnichannel atmospheric cues) increases consumers’ pleasure, arousal and the quality of the environment as a whole, which in turn positively influences purchase intention. However, the impact of dominance is only prominent at the more controlled, laboratory setting, in which purchase intention increases while dominance attenuates
Experimental study on steel plate shear wall with composite frame
No full textIn order to improve the space utilization rate and seismic performance of high-rise buildings, a new seismic structural system, a buckling-restrained steel plate shear wall (SPSW) with concrete-filled L-shaped built-up section tube composite frame is proposed in this study. In this composite shear wall system, the columns in the frame arecomposed of hot-rolled carbon steel H-section members and carbon steel square hollow section tubes, which are connected by steel plates and filled with concrete, and the steel plate shear wall is comprised of an embedded steel plate and several pairs of cold-formed steel hat section buckling-restraining strips. In order to study the seismic performance of this new type of shear wall system, two specimens were prepared and tested subjected to the horizontal cyclic load. Test results show that the two specimens had great bearing capacity, good ductility and energy dissipation capacity. It is indicated that the new shear wall system is reliable and effective to resist lateral forces. The finite element models were established and validated against the experimental results. Based on the parametric analysis results, the coefficient η was proposed to be taken as 0.85 to modify the PFI theory, which could be used to calculate the bearing capacity of the buckling-restrained SPSW with concrete-filled L-shaped built-up section tube composite frame.Keywords: Buckling-restrained; Cold-formed steel; Concrete-filled built-up section tube composite frame; Cyclic shear; Steel plate shear wall (SPSW
Superconvergence of the MINI mixed finite element discretization of the Stokes problem: An experimental study in 3D
No full textStokes flows are a type of fluid flow where convective forces are small in comparison with viscous forces, and momentum transport is entirely due to viscous diffusion. Besides being routinely used as benchmark test cases in numerical fluid dynamics, Stokes flows are relevant in several applications in science and engineering including porous media flow, biological flows, microfluidics, microrobotics, and hydrodynamic lubrication. The present study concerns the discretization of the equations of motion of Stokes flows in three dimensions utilizing the MINI mixed finite element, focusing on the superconvergence of the method which was investigated with numerical experiments using five purpose-made benchmark test cases with analytical solution. Despite the fact that the MINI element is only linearly convergent according to standard mixed finite element theory, a recent theoretical development proves that, for structured meshes in two dimensions, the pressure superconverges with order O(h3/2), as well as the linear part of the computed velocity with respect to the piecewise-linear nodal interpolation of the exact velocity. The numerical experiments documented herein suggest a more general validity of the superconvergence in pressure, possibly to unstructured tetrahedral meshes and even up to quadratic convergence which was observed with one test problem, thereby indicating that there is scope to further extend the available theoretical results on convergence
MRSD: a quantitative approach for assessing suitability of RNA-seq in the investigation of mis-splicing in Mendelian disease
No full textBackground: Variable levels of gene expression between tissues complicates the use of RNA-sequencing of patient biosamples to delineate the impact of genomic variants. Here, we describe a gene- and tissue-specific metric to inform the feasibility of RNAsequencing. This overcomes limitations of using expression values alone as a metric to predict RNA-sequencing utility.Results: We have derived a metric, Minimum Required Sequencing Depth (MRSD) that estimates the depth of sequencing required from RNA-sequencing to achieve user-specified sequencing coverage of a gene, transcript or group of genes. We applied MRSD across four human biosamples (whole blood, lymphoblastoid cell lines (LCLs), skeletal muscle and cultured fibroblasts). MRSD has high precision (90.1- 98.2%) and overcomes transcript region-specific sequencing biases. Applying MRSD scoring to established disease gene panels shows that fibroblasts are the optimum source of RNA, of these four biosamples, for 63.1% of gene panels. Using this approach, up to 67.8% of the variants of uncertain significance in ClinVar that are predicted to impact splicing could be assayed by RNA-sequencing in at least one of the biosamples.Conclusions: We demonstrate the utility and benefits of MRSD as a metric to informfunctional assessment of splicing aberrations, in particular in the context of Mendelian genetic disorders to improve diagnostic yield
Developing a test of reasoning for preadolescents
No full textAs part of an investigation into the relationship between classroom dialogue and student outcome, a test of reasoning has been developed that is suitable for preadolescents (i.e. c.10 to 13-year-olds). Building on previous work but expanding this considerably, the test focuses upon four areas of reasoning: differentiation of facts from opinions, differentiation of reasons from conclusions, inference of implications, and evaluation of multiple reasons. This paper reports on the test’s design and development (including the repeated cycles of piloting and redrafting), highlighting the methodological challenges that were faced (e.g. from linguistic demands), and how these were addressed. It also outlines how the test was trialled in English schools, including its use in a paper-based version with 218 students, and in a digital version with 129 students. Patterns of student performance were comparable across the two samples and also provide evidence for acceptable test reliability and validity. Thus, in addition to spotlighting methodological issues of general relevance within educational research, the paper presents a test that successfully assesses key aspects of student reasoning, The test is the first of its kind to be designed for this age group, and is offered as freely available for future research. Keywords: reasoning test, preadolescents, England, validity, reliability<br/
OUT OF DATE OR BEST BEFORE? A COMMENTARY ON THE RELEVANCE OF ECONOMIC EVALUATIONS OVER TIME
No full textThe impact of time on the applicability and relevance of historical economic evaluations can be considerable. Ignoring this may lead to the use of weak or invalid evidence to inform important research questions or resource allocation decisions, as historical economic evaluations may have reached different conclusions compared to if a similar study been conducted more recently. There are multiple factors that contribute towards evidence becoming outdated including changes to the relevant decision problem (e.g., comparators), changes to parameters (such as costs, utilities, and resource use) and methodological updates (e.g., recommendations on uncertainty analysis). Researchers reviewing economic evaluations need to consider whether changes over time would influence the study design and results if the evaluation were repeated, to the extent that it is no longer helpful or informative. In this paper we summarise these key issues and make recommendations about how and whether researchers can future-proof their economic evaluations
Polymer-induced microcolony compaction in early biofilms: a computer simulation study
No full textMicroscopic organisms, such as bacteria, have the ability of colonizing surfaces and developing biofilms that can determine diseases and infections. Most bacteria secrete a significant amount of extracellular polymer substances that are relevant for biofilm stabilization and growth. In this work, we apply computer simulation and perform experiments to investigate the impact of polymer size and concentration on early biofilm formation and growth. We observe as bacterial cells formed loose, disorganized clusters whenever the effect of diffusion exceeded that of cell growth and division. Addition of model polymeric molecules induced particle self-assembly and aggregation to form compact clusters in a polymer size- and concentration-dependent fashion. We also find that large polymer size or concentration lead to the development of intriguing stripe-like and dendritic colonies. The results obtained by Brownian dynamic simulation closely resemble the morphologies that we experimentally observe in biofilms of a Pseudomonas Putida strain with added polymers. The analysis of the Brownian dynamic simulation results suggests the existence of a threshold polymer concentration that distinguishes between two growth regimes. Below this threshold, the main force driving polymer-induced compaction is hindrance of bacterial cell diffusion, while collective effects play a minor role. Above this threshold, especially for large polymers, polymer-induced compaction is a collective phenomenon driven by depletion forces. Well above this concentration threshold, severely limited diffusion drives the formation of filaments and dendritic colonies