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Comparison of discrete dynamic pipeline models for operational optimization of District Heating Networks

ENERGY REPORTS 2021年 7卷 244-253页

作者： Maurer, Jona Ratzel, Oliver M. Malan, Albertus J. Hohmann, Soeren Karlsruhe Inst Technol Inst Control Syst Wilhelm Jordan Weg 1 D-76131 Karlsruhe Germany

Optimal operation of District Heating Networks (DHNs) is a very challenging task. One of the main challenges for DHNs optimization tool designers is the choice of an adequate dynamic thermal pipeline model which gives a good tradeoff between accurately modeling the physics of the thermodynamic processes and simultaneously yielding a numerically efficient model. To address this, the paper states the main Partial Differential Equation (PDE) which is used to describe the convection of hot water throughout the literature, together with reasonable assumptions that lead to minor deviations from measurements. then, different approaches are described which can be used to solve the respective PDE. More specifically, the very common Node Method (NM), approximations of the NM, the lagrangian approach and different Finite Difference (FD) approaches are presented. the main aim of this work is to provide a qualitative and quantitative comparison of these modeling approaches in the context of optimal DHN operation. Our quantitative results show, that by comparing the different approaches to measurement data, the NM yields the smallest modeling errors for most of the temporal discretization sizes. the qualitative comparison identifies that the lagrangian method lacks the differentiability necessary for the implementation in optimization tools. the advantages of the FD approaches include guaranteeing a fixed number of variables, a constant information depth of the temperature distribution along the pipeline and the simplicity of implementation into optimization tools. the approximations of the NM bring benefits when varying mass flow directions need to be considered, which is a crucial aspect in 4th generation DHNs. (C) 2021 the Author(s). Published by Elsevier Ltd.

关键词： Modeling Pipeline Optimal operation of DHNs

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A grasshopper-based path planning method for unsupported 3D printing of rotor models

A grasshopper-based path planning method for unsupported 3D ...

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Artificial Intelligence and Intelligent Manufacturing (AIIM), international symposium on

作者： Huacan Liu Shulin Zou School of Mechanical and Electrical Engineering Wuhan University of Technology Wuhan China

ISBN: (数字)9798331541729

ISBN: (纸本)9798331541736

Traditional three-dimensional (3D) printing technology generates objects and parts by depositing material layer by layer in the Z-axis direction. However, traditional printing processes require the creation of additional support structures when overhanging structures occur during the printing process. As a result, this technique requires additional material and increases the effective printing time. To overcome these problems, this paper this paper proposes a grasshopper based path planning method for supportless material printing. A series of surfaces are computed by extracting the outer contour lines of the model and the original model is sliced on the surfaces and the five-axis printing G-code generated from the slices will print the original model. the feasibility of the method is demonstrated and unsupported continuous path planning with surface layering is realized.

关键词： Solid modeling Computational modeling Rotors three-dimensional printing Path planning Manufacturing Computational efficiency Carbon Surface treatment optimization

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Research on energy management optimization strategy of regional high proportion renewable energy system 4

Research on energy management optimization strategy of regio...

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4th international symposium on Power Electronics and Control Engineering, ISPECE 2021

作者： Dang, Dongsheng Xu, Chang Bin, Che Shi, Tao Research Institute of Economy and Technology State Grid Ningxia Electric Power Co. Ltd YinchuanNingxia750001 China Nanjing University of Posts and Telecommunications Nanjing210023 China

ISBN: (数字)9781510650374

ISBN: (纸本)9781510650367

this paper mainly studies the energy management of regional integrated energy system with high proportion of renewable energy access. this paper proposes an energy management optimization strategy for regional high proportion renewable energy systems. the goal of this strategy is to minimize the comprehensive electricity cost in the region within a certain time period, and consider diversified distributed power sources and load types, such as wind power generation, photovoltaic power generation, fuel type controllable power generation, battery storage, electric vehicle and interruptible charge. In this paper, a high proportion of renewable energy system in a region is taken as an example to carry out case analysis, the results show that: the strategy can fully tap the renewable energy power generation space, maximize the local consumption of renewable energy power generation, and the strategy has a certain engineering practicability. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Energy management

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Generating Spanning-Tree Sequences of a Fan Graph in Lexicographic Order and Ranking/Unranking Algorithms 7th

Generating Spanning-Tree Sequences of a Fan Graph in Lexicog...

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7th international symposium on Combinatorial optimization (ISCO)

作者： Wu, Ro-Yu Tseng, Cheng-Chia Hung, Ling-Ju Chang, Jou-Ming Lunghwa Univ Sci & Technol Dept Ind Management Taoyuan 333326 Taiwan Natl Taipei Univ Business Inst Informat & Decis Sci Taipei 100025 Taiwan Natl Taipei Univ Business Dept Prod Innovat & Entrepreneurship Taoyuan 324022 Taiwan

ISBN: (纸本)9783031185298;9783031185304

Cameron et al. [27th Int. Conf. Computing and Combinatorics (COCOON 2021), LNCS 13025, pp. 49-60] recently presented an algorithm for generating all spanning trees of a fan graph in O(1)amortized time. the listing of spanning trees fulfills the so-called pivot Gray code property so that successive trees differ by pivoting a single edge around a vertex. they also presented algorithms for ranking and unranking a spanning tree in the listing in O(n) time using O(n) space. In this paper, we first observe that all spanning trees of a fan graph can be naturally represented by integer sequences so that their coding tree has properties with regularity. then, we propose a simple algorithm for generating spanning-tree sequences in lexicographic order in O(1)amortized time according to these properties. Additionally, based on the lexicographic order, we develop ranking and unranking algorithms in O(n)-time using n + O(1) space (i.e., the size of the space is just slightly larger than n).

关键词： Spanning trees Fan graphs generation algorithms ranking/unranking algorithms Constant amortized time algorithms

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Simulation and optimization of hydrogen-based hybrid renewable energy systems: Software tools and applications 4

Simulation and optimization of hydrogen-based hybrid renewab...

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2021 4th international symposium on Hydrogen Energy and Energy Technologies, HEET 2021

作者： Li, Yaze Li, Guodong Li, Jin Bénard, Pierre Chahine, Richard Xiao, Jinsheng Hubei Research Center For New Energy And Intelligent Connected Vehicle School Of Automotive Engineering Wuhan University Of Technology Hubei430070 China Hydrogen Research Institute Université Du Québec À Trois-Rivières QCG8Z 4M3 Canada

With continuous fossil energy consumption and global warming, renewable energy has become more popular. therefore, more and more researchers have begun to study hydrogen-based hybrid renewable energy systems. this article mainly summarizes the commercial software tools and the simulation of hybrid renewable energy systems in recent years. Firstly, the commonly used softwares and research methods are reviewed so that other researchers can choose suitable tools and strategies to conduct their researches. then TRNSYS software is used to perform a case study in Yichang, Hubei, China. the established model is simulated according to the one-year load of the community. the simulation results show that the total power generation of the system can meet the load demand most of the time but is insufficient in some peak periods. the system can further be optimized using optimization methods to fully meet the load. © Published under licence by IOP Publishing Ltd.

关键词： Renewable energy resources

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An Adjoint-based Shape optimization Design System for the Radar Cross Section Reduction 4

An Adjoint-based Shape Optimization Design System for the Ra...

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4th international Applied Computational Electromagnetics Society symposium in China, ACES-China 2021

作者： Li, Ming Liu, Chaoyu Qu, Feng Bai, Junqiang School of Aeronautics Northwestern Polytechnical University Xi'an China

ISBN: (纸本)9781733509619

An efficient shape optimization design system for the Radar Cross Section (RCS) reduction using the adjoint approach is discussed. the Method of Moments (MoM) and the Multilevel Fast Multipole Algorithm (MLFMA) are applied to solve the Combined Field Integral Equation (CFIE) or the Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) equation to calculate the RCS. As for the high-frequency scattering problem, the Physical Optics (PO) method is selected to calculate the RCS due to its efficiency. the gradient of the RCS is obtained by solving the adjoint equations. the code that calculates the derivatives is developed with the help of the Automatic Differentiation (AD) technique. the Free-Form Deformation (FFD) approach is used to parameterize the shape and the Sequential Quadratic Programming (SQP) is chosen as the optimization algorithm. Without a large number of function evaluations, this design system could efficiently obtain the shape that meets the stealth requirements. © 2021 Applied Computational Electromagnetics Society (ACES).

关键词： Method of moments

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A 26GHz Fractional-N Digital Frequency Synthesizer Leveraging Noise Profiles of three Functional Stages

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS 2021年第9期68卷 3063-3067页

作者： Bae, Seongun Lee, Minseob Cho, Hwasuk Sim, Jae-Yoon Pohang Univ Sci & Technol Dept Elect & Elect Engn Pohang 37673 South Korea Samsung Elect Device Solut Div Hwasung 18448 South Korea

this work presents a low-noise millimeter-wave fractional-N digital frequency synthesizer architecture. It is formed by cascading an injection-locked frequency multiplier, an open-loop digital frequency synthesizer and an integer-N LC digital phase-locked loop. though the individual blocks are not novel, the combination synergically achieves a stable low-noise performance by leveraging the merits of three functional stages while suppressing the demerits of them without any complicated calibration or time-consuming optimization. the implemented frequency synthesizer in 40nm CMOS process shows an integrated jitter of 196fs with an in-band phase noise of -93.5dBc/Hz at a 100kHz offset and an in-band fractional spur of -59.4dBc.

关键词： Phase locked loops IIR filters Frequency synthesizers Oscillators Timing Phase noise Jitter Digital phase-locked loop injection lock millimeter-wave band fractional-N generation frequency synthesizer

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Real time monitoring method for temperature overheating of supercritical thermal power unit 4

Real time monitoring method for temperature overheating of s...

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4th international symposium on Power Electronics and Control Engineering, ISPECE 2021

作者： Wu, Hongliang Hebei Guohua Dingzhou Power Generation Co. Ltd DingzhouHebei073000 China

ISBN: (数字)9781510650374

ISBN: (纸本)9781510650367

When the temperature of supercritical thermal power unit is overheated, it is easy to cause power station failure, and even fire in serious cases, resulting in great potential safety hazards. Based on this, it is necessary to optimize the problem of poor real-Time monitoring of thermal power unit temperature overheating. this paper proposes a real-Time monitoring method for the temperature and overheating of supercritical thermal power units. Aiming at the problem of overheating of supercritical thermal power units, this paper optimizes the online temperature monitoring system, the online stator winding end vibration monitoring system and the online generator gas analysis and monitoring structure installed in the steam turbine generator unit of the power station. Based on the above optimization, the time and temperature tracking detection algorithm for thermal power units is improved. through system application analysis, different online monitoring methods are compared, and different online monitoring methods can be flexibly selected to ensure the safe operation of the unit. the experiments show that the real-Time monitoring method of temperature overheating of supercritical thermal power generation unit has high practicability in the process of practical application, can better carry out high temperature early warning and solve the problem of poor monitoring effect. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Monitoring

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Research on automatic generation of test data for multi-path coverage 4

Research on automatic generation of test data for multi-path...

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4th international Conference on Advanced Electronic Materials, Computers and Software Engineering, AEMCSE 2021

作者： Zhang, Meng Li, Honghui Beijing Jiaotong University School of Computer Information Technology Research Center for Network Management Beijing China

ISBN: (纸本)9781665415965

Software testing is a complex and time-consuming task, especially in the part of test case design. therefore, test automation can greatly reduce the consumption of manpower and material resources. the main work of this paper is as follows:1this article designs a total path similarity for the target path group of the code from the perspective of multi-path oriented. And relying on this to generate test data that meets multiple target paths at one time, so as to reduce the number of iterations and time spent.2this article is inspired by the fitness function design of genetic algorithm, and designs a fitness evaluation method for multi-path and single-path.3this paper selects the Beetle Antennae Search algorithm from existing intelligent optimization algorithms. Because it does not require too much information, it performs very well in low- dimensional problems, and only needs one longhorn beetle in the search process, which greatly reduces the amount of calculation. And it is applied to the triangle classification problem program, and compared with the traditional genetic algorithm at the same time. the experimental results verify the correctness of the method, and the Beetle Antennae Search algorithm is more efficient than the genetic algorithm. © 2021 IEEE.

关键词： Genetic algorithms

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Clock Domain Crossing Aware RTL Synthesis using Fusion Compiler in Commercial Display Chip Design

Clock Domain Crossing Aware RTL Synthesis using Fusion Compi...

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Artificial Intelligence and Intelligent Manufacturing (AIIM), international symposium on

作者： BolunLi Weiding Cao Bowei Wu ESWIN Xi’an China XUPT Xi’an China

ISBN: (数字)9798331541729

ISBN: (纸本)9798331541736

As the performance requirements of display chips increase, less area, less power consumption, good performance display chip become more critical factors for LCD panel manufacturer. So this puts a lot of demands on chip development. Chip designer need speed up the chip development iteration rate. there are many methods to achieve this goal by the way introduce new problem. For example, to get better performance design house will use same RTL code do process transfer. But same RTL may not suitable in timing aspect for difference design process. RTL designer use high level Synthesis tool create RTL more fastly. Some company may purchase soft encrypted RTL IP from IP vendor. But high level synthesis rtl & encrypted rtl make RTL design unreadable. It increase clock domain crossing risk during design optimization. these give more challenge for design synthesis & implementation engineer. Fusion Compile (FC) is an EDA tool from Synopsys. It combined synthesis stage and place route. Make implementation step more efficiency. More compact implementation method speed up design cycle. More ever It make design timing closure more easily and get good power area. Design house can use this tool achieve difficult design goal. We present a fusion compile design flow. To solve clock domain crossing issue in implementation design stage and apply this flow for one of arithmetic block in commercial display chip. Get good optimize results avoid any clock domain crossing risk.

关键词： Power demand Machine learning algorithms codes Timing High level synthesis IP networks Cryptography Chip scale packaging optimization Clocks

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