273,440 research outputs found

    Introduction Of Clusterization Principles In The Solution Of Problems Of Energy Efficiency And Ecological Safety Of The Existent Building Fund

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    The aim of the work is to introduce clusterization principles in the solution of problems of energy efficiency and ecological safety of the existent building fund. The material of the research is the process of modeling of energetically effective architecture-building clusters. In this sense it is topical and expedient to elaborate technologies and schemes, able to support making decisions as to the formation of energetically effective architecture-building clusters. The main attention is paid to the solution of infrastructure problems of energy saving of the architecture-building branch, connected with the absence of universal models, distinct algorithms of the formation of energy efficiency clusters and reliable instruments of their activity optimization. But realization of advantages of energy efficiency clusters is possible only at introducing effective mechanisms of the formation of a structure, able to provide a result, optimal by an energy efficiency criterion. The work offers a scheme of the formation process of such structure. The synthesis of models of energetically effective architecture-building clusters is based on principles of the systemic construction of geometric models and provides the imitative modeling of different development scenarios of synthesized clusters. At this stage of the research a function of making decisions as to the real cluster formation is left for experts. But an algorithm of the synthesis of models provides the formation of a knowledge base that will be in further a base of an ā€œinternal modelā€ of the intellectual system of supporting decisions making, elaborated for modeling cluster structures. The scientific novelty of the work is in the elaboration of theoretical bases of the technology of coordinating the structure with object properties

    Submodular Load Clustering with Robust Principal Component Analysis

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    Traditional load analysis is facing challenges with the new electricity usage patterns due to demand response as well as increasing deployment of distributed generations, including photovoltaics (PV), electric vehicles (EV), and energy storage systems (ESS). At the transmission system, despite of irregular load behaviors at different areas, highly aggregated load shapes still share similar characteristics. Load clustering is to discover such intrinsic patterns and provide useful information to other load applications, such as load forecasting and load modeling. This paper proposes an efficient submodular load clustering method for transmission-level load areas. Robust principal component analysis (R-PCA) firstly decomposes the annual load profiles into low-rank components and sparse components to extract key features. A novel submodular cluster center selection technique is then applied to determine the optimal cluster centers through constructed similarity graph. Following the selection results, load areas are efficiently assigned to different clusters for further load analysis and applications. Numerical results obtained from PJM load demonstrate the effectiveness of the proposed approach.Comment: Accepted by 2019 IEEE PES General Meeting, Atlanta, G

    Real-time dynamics of clusters. II. I_2X_n (n=1; X=He, Ne, and H_2), picosecond fragmentation

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    In this second paper (II) of a series, we report our picosecond time-resolved studies of the state-to-state rates of vibrational predissociation in iodineā€“rare gas (van der Waals) clusters. Particular focus is on the simplest system, I2He, which serves as a benchmark for theoretical modeling. Comparisons with I2Ne and I2H2 are also presented. The results from measurements made in real time are compared with those deduced from linewidth measurements, representing a rare example of a system studied by both methods under identical conditions and excited to the same quantum (v[script ']i) states. The discrepancies are discussed in relation to the origin of the broadening and preparation of the state. The rates as a function of v[script ']i display a nonlinear behavior which is examined in relation to the energy-gap law. The measured absolute rates and their dependence on v[script ']i are compared with numerous calculations invoking classical, quantum, and semiclassical theories. In the following paper (III in this series), the cluster size of the same system, I2Xn, is increased (n=2ā€“4) and the dynamics are studied

    Structural origins of electronic conduction in amorphous copper-doped alumina

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    We perform an {\it ab initio} modeling of amorphous copper-doped alumina (a-Al2_2O3_3:Cu), a prospective memory material based on resistance switching, and study the structural origin of electronic conduction in this material. We generate molecular dynamics based models of a-Al2_2O3_3:Cu at various Cu-concentrations and study the structural, electronic and vibrational properties as a function of Cu-concentration. Cu atoms show a strong tendency to cluster in the alumina host, and metallize the system by filling the band gap uniformly for higher Cu-concentrations. We also study thermal fluctuations of the HOMO-LUMO energy splitting and observe the time evolution of the size of the band gap, which can be expected to have an important impact on the conductivity. We perform a numerical computation of conduction pathways, and show its explicit dependence on Cu connectivity in the host. We present an analysis of ion dynamics and structural aspects of localization of classical normal modes in our models

    Dispersion Correction Derived from First Principles for Density Functional Theory and Hartreeāˆ’Fock Theory

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    The modeling of dispersion interactions in density functional theory (DFT) is commonly performed using an energy correction that involves empirically fitted parameters for all atom pairs of the system investigated. In this study, the first-principles-derived dispersion energy from the effective fragment potential (EFP) method is implemented for the density functional theory (DFT-D(EFP)) and Hartreeā€“Fock (HF-D(EFP)) energies. Overall, DFT-D(EFP) performs similarly to the semiempirical DFT-D corrections for the test cases investigated in this work. HF-D(EFP) tends to underestimate binding energies and overestimate intermolecular equilibrium distances, relative to coupled cluster theory, most likely due to incomplete accounting for electron correlation. Overall, this first-principles dispersion correction yields results that are in good agreement with coupled-cluster calculations at a low computational cost

    INTRODUCTION OF CLUSTERIZATION PRINCIPLES IN THE SOLUTION OF PROBLEMS OF ENERGY EFFICIENCY AND ECOLOGICAL SAFETY OF THE EXISTENT BUILDING FUND

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    The aim of the work is to introduce clusterization principles in the solution of problems of energy efficiency and ecological safety of the existent building fund. The material of the research is the process of modeling of energetically effective architecture-building clusters. In this sense it is topical and expedient to elaborate technologies and schemes, able to support making decisions as to the formation of energetically effective architecture-building clusters. The main attention is paid to the solution of infrastructure problems of energy saving of the architecture-building branch, connected with the absence of universal models, distinct algorithms of the formation of energy efficiency clusters and reliable instruments of their activity optimization. But realization of advantages of energy efficiency clusters is possible only at introducing effective mechanisms of the formation of a structure, able to provide a result, optimal by an energy efficiency criterion. The work offers a scheme of the formation process of such structure. The synthesis of models of energetically effective architecture-building clusters is based on principles of the systemic construction of geometric models and provides the imitative modeling of different development scenarios of synthesized clusters. At this stage of the research a function of making decisions as to the real cluster formation is left for experts. But an algorithm of the synthesis of models provides the formation of a knowledge base that will be in further a base of an ā€œinternal modelā€ of the intellectual system of supporting decisions making, elaborated for modeling cluster structures. The scientific novelty of the work is in the elaboration of theoretical bases of the technology of coordinating the structure with object properties

    Energy Consumption Of Visual Sensor Networks: Impact Of Spatio-Temporal Coverage

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    Wireless visual sensor networks (VSNs) are expected to play a major role in future IEEE 802.15.4 personal area networks (PAN) under recently-established collision-free medium access control (MAC) protocols, such as the IEEE 802.15.4e-2012 MAC. In such environments, the VSN energy consumption is affected by the number of camera sensors deployed (spatial coverage), as well as the number of captured video frames out of which each node processes and transmits data (temporal coverage). In this paper, we explore this aspect for uniformly-formed VSNs, i.e., networks comprising identical wireless visual sensor nodes connected to a collection node via a balanced cluster-tree topology, with each node producing independent identically-distributed bitstream sizes after processing the video frames captured within each network activation interval. We derive analytic results for the energy-optimal spatio-temporal coverage parameters of such VSNs under a-priori known bounds for the number of frames to process per sensor and the number of nodes to deploy within each tier of the VSN. Our results are parametric to the probability density function characterizing the bitstream size produced by each node and the energy consumption rates of the system of interest. Experimental results reveal that our analytic results are always within 7% of the energy consumption measurements for a wide range of settings. In addition, results obtained via a multimedia subsystem show that the optimal spatio-temporal settings derived by the proposed framework allow for substantial reduction of energy consumption in comparison to ad-hoc settings. As such, our analytic modeling is useful for early-stage studies of possible VSN deployments under collision-free MAC protocols prior to costly and time-consuming experiments in the field.Comment: to appear in IEEE Transactions on Circuits and Systems for Video Technology, 201
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