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Energy Minimization for Heterogenous Traffic Coexistence with Puncturing in Mobile Edge Computing-Based Industrial Internet of Things
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作者 Wang Xue Wang Ying +1 位作者 Fei Zixuan Zhao Junwei 《China Communications》 SCIE CSCD 2024年第10期167-180,共14页
Puncturing has been recognized as a promising technology to cope with the coexistence problem of enhanced mobile broadband(eMBB) and ultra-reliable low latency communications(URLLC)traffic. However, the steady perform... Puncturing has been recognized as a promising technology to cope with the coexistence problem of enhanced mobile broadband(eMBB) and ultra-reliable low latency communications(URLLC)traffic. However, the steady performance of eMBB traffic while meeting the requirements of URLLC traffic with puncturing is a major challenge in some realistic scenarios. In this paper, we pay attention to the timely and energy-efficient processing for eMBB traffic in the industrial Internet of Things(IIoT), where mobile edge computing(MEC) is employed for data processing. Specifically, the performance of eMBB traffic and URLLC traffic in a MEC-based IIoT system is ensured by setting the threshold of tolerable delay and outage probability, respectively. Furthermore,considering the limited energy supply, an energy minimization problem of eMBB device is formulated under the above constraints, by jointly optimizing the resource blocks(RBs) punctured by URLLC traffic, data offloading and transmit power of eMBB device. With Markov's inequality, the problem is reformulated by transforming the probabilistic outage constraint into a deterministic constraint. Meanwhile, an iterative energy minimization algorithm(IEMA) is proposed.Simulation results demonstrate that our algorithm has a significant reduction in the energy consumption for eMBB device and achieves a better overall effect compared to several benchmarks. 展开更多
关键词 energy minimization enhanced mobile broadband(eMBB)and ultra-reliable low latency communications(URLLC)coexistence industrial Internet of Things(IIoT) mobile edge computing(MEC) PUNCTURING
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Energy-Minimizing Curve Fitting for High-Order Surface Mesh Generation 被引量:5
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作者 Karsten Bock Jorg Stiller 《Applied Mathematics》 2014年第21期3318-3327,共10页
We investigate different techniques for fitting Bézier curves to surfaces in context of high-order curvilinear mesh generation. Starting from distance-based least-squares fitting we develop an incremental algorit... We investigate different techniques for fitting Bézier curves to surfaces in context of high-order curvilinear mesh generation. Starting from distance-based least-squares fitting we develop an incremental algorithm, which incorporates approximations of stretch and bending energy. In the process, the algorithm reduces the energy weight in favor of accuracy, leading to an optimized set of sampling points. This energy-minimizing fitting strategy is applied to analytically defined as well as triangulated surfaces. The results confirm that the proposed method straightens and shortens the curves efficiently. Moreover the method preserves the accuracy and convergence behavior of distance-based fitting. Preliminary application to surface mesh generation shows a remarkable improvement of patch quality in high curvature regions. 展开更多
关键词 Curvilinear Mesh Generation High-Order Methods Bézier Curves Curve Fitting energy Minimization
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Thermodynamic analysis of combined reforming process using Gibbs energy minimization method: In view of solid carbon formation 被引量:5
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作者 Behzad Nematollahi Mehran Rezaei +1 位作者 Ebrahim Nemati Lay Majid Khajenoori 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2012年第6期694-702,共9页
Thermodynamic analysis was applied to study combined partial oxidation and carbon dioxide reforming of methane in view of carbon formation. The equilibrium calculations employing the Gibbs energy minimization were per... Thermodynamic analysis was applied to study combined partial oxidation and carbon dioxide reforming of methane in view of carbon formation. The equilibrium calculations employing the Gibbs energy minimization were performed upon wide ranges of pressure (1-25 atm), temperature (600-1300 K), carbon dioxide to methane ratio (0-2) and oxygen to methane ratio (0-1). The thermodynamic results were compared with the results obtained over a Ru supported catalyst. The results revealed that by increasing the reaction pressure methane conversion decreased. Also it was found that the atmospheric pressure is the preferable pressure for both dry reforming and partial oxidation of methane and increasing the temperature caused increases in both activity of carbon and conversion of methane. The results clearly showed that the addition of O2 to the feed mixture could lead to a reduction of carbon deposition. 展开更多
关键词 combined reforming carbon deposition chemical equilibrium Gibbs energy minimization method thermodynamic analysis
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Efficient Construction of B-Spline Curves with Minimal Internal Energy 被引量:6
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作者 Gang Xu Yufan Zhu +3 位作者 Lishan Deng Guozhao Wang Bojian Li Kin-chuen Hui 《Computers, Materials & Continua》 SCIE EI 2019年第3期879-892,共14页
In this paper,we propose an efficient method to construct energy-minimizing B-spline curves by using discrete mask method.The linear relations between control points are firstly derived for different energy-minimizati... In this paper,we propose an efficient method to construct energy-minimizing B-spline curves by using discrete mask method.The linear relations between control points are firstly derived for different energy-minimization problems,then the construction of B-spline curve with minimal internal energy can be addressed by solving a sparse linear system.The existence and uniqueness of the solution for the linear system are also proved.Experimental results show the efficiency of the proposed approach,and its application in 1 G blending curve construction is also presented. 展开更多
关键词 Minimal energy B-spline curves geometric construction discrete mask method sparse linear system.
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Optimized model-based control of main mine ventilation air flows with minimized energy consumption 被引量:5
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作者 S.Sjostrom E.Klintenas +1 位作者 P.Johansson J.Nyqvist 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2020年第4期533-539,共7页
In early 2018,the Boliden Garpenberg operation implemented an optimized control strategy as an addition to the existing ventilation on demand system.The purpose of the strategy is to further minimize energy use for ma... In early 2018,the Boliden Garpenberg operation implemented an optimized control strategy as an addition to the existing ventilation on demand system.The purpose of the strategy is to further minimize energy use for main and booster fans,whilst also fulfilling airflow setpoints without violating constraints such as min/max differential pressure over fans and interaction of air between areas in mines.Using air flow measurements and a dynamical model of the ventilation system,a mine-wide coordination control of fans can be carried out.The numerical model is data driven and derived from historical operational data or step changes experiments.This makes both initial deployment and lifetime model maintenance,as the mine evolves,a comparably easy operation.The control has been proven to operate in a stable manner over long periods without having to re-calibrate the model.Results prove a 40%decrease in energy use for the fans involved and a greater controllability of air flow.Moreover,a 15%decrease of the total air flow into the mine will give additional proportional heating savings during winter periods.All in all,the multivariable controller shows a correlation between production in the mine and the ventilation system performance superior to all of its predecessors. 展开更多
关键词 Mine ventilation Ventilation on demand Optimized model-based control Minimized energy consumption Advanced process control
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Color Correction for Multi-view Video Using Energy Minimization of View Networks 被引量:4
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作者 Kenji Yamamoto Ryutaro Oi 《International Journal of Automation and computing》 EI 2008年第3期234-245,共12页
Systems using numerous cameras are emerging in many fields due to their ease of production and reduced cost, and one of the fields where they are expected to be used more actively in the near future is in image-based ... Systems using numerous cameras are emerging in many fields due to their ease of production and reduced cost, and one of the fields where they are expected to be used more actively in the near future is in image-based rendering (IBR). Color correction between views is necessary to use multi-view systems in IBR to make audiences feel comfortable when views are switched or when a free viewpoint video is displayed. Color correction usually involves two steps: the first is to adjust camera parameters such as gain, brightness, and aperture before capture, and the second is to modify captured videos through image processing. This paper deals with the latter, which does not need a color pattern board. The proposed method uses scale invariant feature transform (SIFT) to detect correspondences, treats RGB channels independently, calculates lookup tables with an energy-minimization approach, and corrects captured video with these tables. The experimental results reveal that this approach works well. 展开更多
关键词 MULTI-VIEW color correction image-based rendering (IBR) view networks (VNs) scale invariant feature transform (SIFT) energy minimization.
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A new extension algorithm for cubic B-splines based on minimal strain energy 被引量:8
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作者 MO Guo-liang ZHAO Ya-nan 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第12期2043-2049,共7页
Extension of a B-spline curve or surface is a useful function in a CAD system. This paper presents an algorithm for extending cubic B-spline curves or surfaces to one or more target points. To keep the extension curve... Extension of a B-spline curve or surface is a useful function in a CAD system. This paper presents an algorithm for extending cubic B-spline curves or surfaces to one or more target points. To keep the extension curve segment GC^2-continuous with the original one, a family of cubic polynomial interpolation curves can be constructed. One curve is chosen as the solution from a sub-class of such a family by setting one GC^2 parameter to be zero and determining the second GC^2 parameter by minimizing the strain energy. To simplify the final curve representation, the extension segment is reparameterized to achieve C-continuity with the given B-spline curve, and then knot removal from the curve is done. As a result, a sub-optimized solution subject to the given constraints and criteria is obtained. Additionally, new control points of the extension B-spline segment can be determined by solving lower triangular linear equations. Some computing examples for comparing our method and other methods are given. 展开更多
关键词 GC^2-continuous EXTENSION Minimal strain energy Knot removal Reparametrization
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Multiple bifurcations and local energy minimizers in thermoelastic martensitic transformations 被引量:1
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作者 Chen Xuan Shurong Ding Yongzhong Huo 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第5期660-671,共12页
Thermoelastic martensitic transformations in shape memory alloys can be modeled on the basis of nonlinear elastic theory.Microstructures of fine phase mixtures are local energy minimizers of the total energy.Using a o... Thermoelastic martensitic transformations in shape memory alloys can be modeled on the basis of nonlinear elastic theory.Microstructures of fine phase mixtures are local energy minimizers of the total energy.Using a one-dimensional effective model,we have shown that such microstructures are inhomogeneous solutions of the nonlinear Euler-Lagrange equation and can appear upon loading or unloading to certain critical conditions,the bifurcation conditions.A hybrid numerical method is utilized to calculate the inhomogeneous solutions with a large number of interfaces.The characteristics of the solutions are clarified by three parameters:the number of interfaces,the interface thickness,and the oscillating amplitude.Approximated analytical expressions are obtained for the interface and inhomogeneity energies through the numerical solutions. 展开更多
关键词 Thermoelastic martensitic transformation MICROSTRUCTURES Nonlinear elasticity BIFURCATION energy minimizer
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REGULARITIES AND SINGULARITIES OF THE ENERGY MINIMIZERS OF THE HEISENBERG GROUP TARGETS 被引量:1
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作者 贾高 《Acta Mathematica Scientia》 SCIE CSCD 2003年第4期447-452,共6页
In this paper, the properties of the maps for the Heisenberg group targets are studied. For u e∈W1,α(Ω, Hm), some Poincare type inequalities are proved. For the energy minimizers, the ∈-regularity theorems and the... In this paper, the properties of the maps for the Heisenberg group targets are studied. For u e∈W1,α(Ω, Hm), some Poincare type inequalities are proved. For the energy minimizers, the ∈-regularity theorems and the singularity theorems are obtained. 展开更多
关键词 Heisenberg group energy minimizer Legendrian map regularity singularity
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Design of Energy Efficient WSN Using a Noble SMOWA Algorithm
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作者 Avishek Banerjee Deepak Garg +4 位作者 Victor Das Laxminarayan Sahoo Ira Nath Vijayakumar Varadarajan Ketan Kotecha 《Computers, Materials & Continua》 SCIE EI 2022年第8期3585-3600,共16页
In this paper,the establishment of efficientWireless Sensor Network(WSN)networks has been projected to minimize the consumption of energy using a new Self-adaptive Multi-Objective Weighted Approach(SMOWA)algorithm for... In this paper,the establishment of efficientWireless Sensor Network(WSN)networks has been projected to minimize the consumption of energy using a new Self-adaptive Multi-Objective Weighted Approach(SMOWA)algorithm for solving a multi-objective problem.The Different WSN nodes deployment policies have been proposed and applied in this paper to design an efficientWireless Sensor Network to minimize energy consumption.After that,the cluster head for each cluster has been selected with the help of the duty cycle.After configuring the WSN networks,the SMOWA algorithms have been developed to obtain the minimum energy consumption for the networks.Energy minimization,as well as the amount of day-saving,has been calculated for the differentWSNswhich has been configured through different deployment policies.The major finding of the research paper is to improve the durability of Wireless Sensor Network(i)applying different deployment strategies:(Random,S pattern and nautilus shell pattern),and(ii)using a new Meta-heuristic algorithm(SMOWA Algorithm).In this research,the lifetime of WSN has been increased to a significant level.To choose the best result set from all the obtained results set some constraints such as“equivalent distribution”,“number of repetitions”,“maximum amount energy storage by a node”has been set to an allowable range. 展开更多
关键词 Wireless Sensor Network(WSN) Self-adaptive Multi-Objective Weighted Approach(SMOWA) deployment strategies Meta-heuristicMethods energy minimization duty cycle
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Improvement of energy model based on cubic interpolation curve 被引量:1
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作者 Li Peipei Li Xuemei Wei Yu 《Computer Aided Drafting,Design and Manufacturing》 2012年第1期35-39,共5页
In CAGD and CG, energy model is often used to control the curves and surfaces shape. In curve/surface modeling, we can get fair curve/surface by minimizing the energy of curve/surface. However, our research indicates ... In CAGD and CG, energy model is often used to control the curves and surfaces shape. In curve/surface modeling, we can get fair curve/surface by minimizing the energy of curve/surface. However, our research indicates that in some cases we can't get fair curves/surface using the current energy model. So an improved energy model is presented in this paper. Examples are also included to show that fair curves can be obtained using the improved energy model. 展开更多
关键词 energy minimization energy model
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THE ENERGY FUNCTION WITH RESPECT TO THE ZEROS OF THE EXCEPTIONAL HERMITE POLYNOMIALS
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作者 Agota P.HORVATH 《Acta Mathematica Scientia》 SCIE CSCD 2017年第5期1483-1496,共14页
We examine the energy function with respect to the zeros of exceptional Hermite polynomials. The localization of the eigenvalues of the Hessian is given in the general case.In some special arrangements we have a more ... We examine the energy function with respect to the zeros of exceptional Hermite polynomials. The localization of the eigenvalues of the Hessian is given in the general case.In some special arrangements we have a more precise result on the behavior of the energy function. Finally we investigate the energy function with respect to the regular zeros of the exceptional Hermite polynomials. 展开更多
关键词 exceptional Hermite polynomials system of minimal energy energy function partitioned matrices
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Reliability-aware mapping and links voltage assignment for energy-efficient networks-on-chip
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作者 谢晓娜 Zhu Qingxin +1 位作者 Chang Zhengwei Jiang Wei 《High Technology Letters》 EI CAS 2014年第2期201-207,共7页
As feature sizes shrink,low energy consumption,high reliability and high performance become key objectives of network-on-chip(NoC) design.In this paper,an integrated approach is presented to map IP cores onto NoC arch... As feature sizes shrink,low energy consumption,high reliability and high performance become key objectives of network-on-chip(NoC) design.In this paper,an integrated approach is presented to map IP cores onto NoC architecture and assign voltage levels for each link,such that the communication energy is minimized under constraints of bandwidth and reliability.The design space is explored using tabu search.In order to select optimal voltage level for the links,an energy-efficiency driven heuristic algorithm is proposed to perform energy/reliability trade-off by exploiting communication slack.Experimental results show that the ordinary energy optimization techniques ignoring the influence of voltage on fault rates could lead to drastically decreased communication reliability of NoCs,and the proposed approach can produce reliable and energy-efficient implementations. 展开更多
关键词 network-on-chip (NoC) energy minimization RELIABILITY MAPPING voltage assignment
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Numerical simulation of dense particle-gas two-phase flow using the minimal potential energy principle
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作者 Xiangjun Liu Xuchang Xu Wurong Zhang 《Journal of University of Science and Technology Beijing》 CSCD 2006年第4期301-307,共7页
A simulation method of dense particle-gas two-phase flow has been developed. The binding force is introduced to present the impact of particle clustering and its expression is deduced according to the principle of min... A simulation method of dense particle-gas two-phase flow has been developed. The binding force is introduced to present the impact of particle clustering and its expression is deduced according to the principle of minimal potential energy. The cluster collision, break-up and coalescence models are proposed based on the assumption that the particle cluster are treated as one discrete phase. These models are used to numerically study the two-phase flow field in a circulating fluidized bed (CFB). Detailed results of the cluster structure, cluster size, particle volume fraction, gas velocity, and particle velocity are obtained. The correlation between the simulation results and experimental data justifies that these models and algorithm are reasonable, and can be used to efficiently study the dense particle-gas two-phase flow. 展开更多
关键词 dense particle-gas two-phase flow clusters modeling circulating fluidized bed (CFB) principle of minimal potential energy
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Simulation of Polyhedral Crystal Growth Based on the Estimated Surface Energy of Crystallographic Planes
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作者 Takuya Uehara 《Materials Sciences and Applications》 2021年第11期519-533,共15页
Polyhedral shapes can be found in crystalline materials ranging from macroscopic natural mineral solids to microscopic or nanoscopic particles. These shapes originate from the crystallographic properties of the consti... Polyhedral shapes can be found in crystalline materials ranging from macroscopic natural mineral solids to microscopic or nanoscopic particles. These shapes originate from the crystallographic properties of the constituting material, and the outer shape depends on several unique habit planes. In this study, polyhedral crystal growth was simulated considering the surface energy and crystallographic characteristics. A series of polyhedrons, including cube, truncated hexahedron, cuboctahedron, truncated octahedron, and regular octahedron, was targeted. First, the polyhedron’s static surface energy and dynamic energy variation during crystal growth were computed. Then, the crystal-growth process was simulated based on the energy minimization policy. Interestingly, when the simulation began with truncated hexahedral nucleus, the shape changed to a cuboctahedron;however, a certain type of truncated octahedron was obtained when starting with different types of truncated octahedrons. In addition, once converged cuboctahedron abruptly changed the shape to a truncated octahedron as the crystal became larger. These results were supported by the static and dynamic energy curves. Furthermore, the method was applied to different materials by assuming virtual parameters, yielding various morphologies. 展开更多
关键词 POLYHEDRON Crystalline Material Morphology Nanoparticle energy Minimization Crystal-Growth Simulation
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A review of optimization methods for computation offloading in edge computing networks 被引量:6
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作者 Kuanishbay Sadatdiynov Laizhong Cui +3 位作者 Lei Zhang Joshua Zhexue Huang Salman Salloum Mohammad Sultan Mahmud 《Digital Communications and Networks》 SCIE CSCD 2023年第2期450-461,共12页
Handling the massive amount of data generated by Smart Mobile Devices(SMDs)is a challenging computational problem.Edge Computing is an emerging computation paradigm that is employed to conquer this problem.It can brin... Handling the massive amount of data generated by Smart Mobile Devices(SMDs)is a challenging computational problem.Edge Computing is an emerging computation paradigm that is employed to conquer this problem.It can bring computation power closer to the end devices to reduce their computation latency and energy consumption.Therefore,this paradigm increases the computational ability of SMDs by collaboration with edge servers.This is achieved by computation offloading from the mobile devices to the edge nodes or servers.However,not all applications benefit from computation offloading,which is only suitable for certain types of tasks.Task properties,SMD capability,wireless channel state,and other factors must be counted when making computation offloading decisions.Hence,optimization methods are important tools in scheduling computation offloading tasks in Edge Computing networks.In this paper,we review six types of optimization methods-they are Lyapunov optimization,convex optimization,heuristic techniques,game theory,machine learning,and others.For each type,we focus on the objective functions,application areas,types of offloading methods,evaluation methods,as well as the time complexity of the proposed algorithms.We discuss a few research problems that are still open.Our purpose for this review is to provide a concise summary that can help new researchers get started with their computation offloading researches for Edge Computing networks. 展开更多
关键词 Edge computing Computation offloading Latency and energy consumption minimization
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HVAC energy cost minimization in smart grids: A cloud-based demand side management approach with game theory optimization and deep learning 被引量:1
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作者 Rahman Heidarykiany Cristinel Ababei 《Energy and AI》 EI 2024年第2期331-345,共15页
In this paper, we present a novel cloud-based demand side management (DSM) optimization approach for the cost reduction of energy usage in heating, ventilation and air conditioning (HVAC) systems in residential homes ... In this paper, we present a novel cloud-based demand side management (DSM) optimization approach for the cost reduction of energy usage in heating, ventilation and air conditioning (HVAC) systems in residential homes at the district level. The proposed approach achieves optimization through scheduling of HVAC energy usage within permissible bounds set by house users. House smart home energy management (SHEM) devices are connected to the utility/aggregator via a dedicated communication network that is used to enable DSM. Each house SHEM can predict its own HVAC energy usage for the next 24 h using minimalistic deep learning (DL) prediction models. These predictions are communicated to the aggregator, which will then do day ahead optimizations using the proposed game theory (GT) algorithm. The GT model captures the interaction between aggregator and customers and identifies a solution to the GT problem that translates into HVAC energy peak shifting and peak reduction achieved by rescheduling HVAC energy usage. The found solution is communicated by the aggregator to houses SHEM devices in the form of offers via DSM signals. If customers’ SHEM devices accept the offer, then energy cost reduction will be achieved. To validate the proposed algorithm, we conduct extensive simulations with a custom simulation tool based on GridLab-D tool, which is integrated with DL prediction models and optimization libraries. Results show that HVAC energy cost can be reduced by up to 36% while indirectly also reducing the peak-to-average (PAR) and the aggregated net load by up to 9.97%. 展开更多
关键词 Day ahead demand side management(DSM) Appliance energy usage prediction Residential energy usage scheduling flexibility Market incentives Non-cooperative game theory(GT) Dynamic price(DP) energy cost minimization Electricity cost minimization Peak-to-average ratio(PAR)minimization Machine learning(ML) Long short-term memory(LSTM) Smart Home energy Management(SHEM) Load shifting Internet of Things(ioT)applications Smart grid Heating Ventilation and air conditioning(HVAC)
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The thermodynamics analysis and experimental validation for complicated systems in CO_2 hydrogenation process 被引量:3
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作者 Chunmiao Jia Jiajian Gao +2 位作者 Yihu Dai Jia Zhang Yanhui Yang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2016年第6期1027-1037,共11页
Catalytic conversion of COinto chemicals and fuels is an alternative to alleviate climate change and ocean acidification.The catalytic reduction of COby Hcan lead to the formation of various products:carbon monoxide,c... Catalytic conversion of COinto chemicals and fuels is an alternative to alleviate climate change and ocean acidification.The catalytic reduction of COby Hcan lead to the formation of various products:carbon monoxide,carboxylic acids,aldehydes,alcohols and hydrocarbons.In this paper,a comprehensive thermodynamics analysis of COhydrogenation is conducted using the Gibbs free energy minimization method.The results show that COreduction to CO needs a high temperature and H/COratio to achieve a high COconversion.However,synthesis of methanol from COneeds a relatively high pressure and low temperature to minimize the reverse water-gas shift reaction.Direct COhydrogenation to formic acid or formaldehyde is thermodynamically limited.On the contrary,production of CHfrom COhydrogenation is the thermodynamically easiest reaction with nearly 100%CH4 yield at moderate conditions.In addition,complex reactions with more than one product are also calculated in this work.Among the considered carboxylic acids(HCOOH,CHCOOH and CHCOOH),propionic acid dominates in the product stream(selectivity above 90%).The same trend can also be found in the hydrogenation of COto aldehydes and alcohols with the major product of propionaldehyde and butanol,respectively.In the process of COhydrogenation to alkenes,low temperature,high pressure,and high Hpartial pressure favor the COconversion.CHis the most thermodynamically favorable among all considered alkynes under different temperatures and pressures.The thermodynamic calculations are validated with experimental results,suggesting that the Gibbs free energy minimization method is effective for thermodynamically understanding the reaction network involved in the COhydrogenation process,which is helpful for the development of high-performance catalysts. 展开更多
关键词 CO2 hydrogenation Thermodynamics analysis Gibbs free energy minimization method
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3D Multiphase Piecewise Constant Level Set Method Based on Graph Cut Minimization 被引量:2
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作者 Tiril P Gurholt Xuecheng Tai 《Numerical Mathematics(Theory,Methods and Applications)》 SCIE 2009年第4期403-420,共18页
Segmentation of three-dimensional(3D) complicated structures is of great importance for many real applications.In this work we combine graph cut minimization method with a variant of the level set idea for 3D segmenta... Segmentation of three-dimensional(3D) complicated structures is of great importance for many real applications.In this work we combine graph cut minimization method with a variant of the level set idea for 3D segmentation based on the Mumford-Shah model.Compared with the traditional approach for solving the Euler-Lagrange equation we do not need to solve any partial differential equations.Instead,the minimum cut on a special designed graph need to be computed.The method is tested on data with complicated structures.It is rather stable with respect to initial value and the algorithm is nearly parameter free.Experiments show that it can solve large problems much faster than traditional approaches. 展开更多
关键词 Piecewise constant level set method energy minimization graph cut SEGMENTATION three-dimensional.
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Oxidative reforming of methane for hydrogen and synthesis gas production:Thermodynamic equilibrium analysis 被引量:2
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作者 Antonio C.D.Freitas Reginaldo Guirardello 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2012年第5期571-580,共10页
A thermodynamic analysis of methane oxidative reforming was carried out by Gibbs energy minimization (at constant pressure and temperature) and entropy maximization (at constant pressure and enthalpy) methods,to d... A thermodynamic analysis of methane oxidative reforming was carried out by Gibbs energy minimization (at constant pressure and temperature) and entropy maximization (at constant pressure and enthalpy) methods,to determine the equilibrium compositions and equilibrium temperatures,respectively.Both cases were treated as optimization problems (non-linear programming formulation).The GAMS 23.1 software and the CONOPT2 solver were used in the resolution of the proposed problems.The hydrogen and syngas production were favored at high temperatures and low pressures,and thus the oxygen to methane molar ratio (O 2 /CH 4) was the dominant factor to control the composition of the product formed.For O 2 /CH 4 molar ratios higher than 0.5,the oxidative reforming of methane presented autothermal behavior in the case of either utilizing O 2 or air as oxidant agent,but oxidation reaction with air possessed the advantage of avoiding peak temperatures in the system,due to change in the heat capacity of the system caused by the addition of nitrogen.The calculated results were compared with previously published experimental and simulated data with a good agreement between them. 展开更多
关键词 thermodynamic analysis methane oxidative reforming Gibbs energy minimization entropy maximization hydrogen and syngas production
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