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低剂量CT;CT成像;全变分;稀疏字典学习 1

联邦边缘学习;量化优化;带宽分配;训练时间最小化 1

随机优化;图形引导最小化;超梯度法;融合逻辑回归;图导向正则化逻辑回归 1

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Mechanism on minimization of excess sludge in oxic-settling-anaerobic (OSA) process

WANG Jianfang, ZHAO Qingliang, JIN Wenbiao, LIN Jikan

《环境科学与工程前沿(英文)》 2008年 第2卷 第1期   页码 36-43 doi: 10.1007/s11783-008-0001-4

摘要: The oxic-settling-anaerobic (OSA) process is a promising wastewater treatment technique for efficiently reducing sludge production and improving the stability of process operation. In this paper, the possible factors of sludge reduction such as sludge decay, uncoupled metabolism, and anaerobic oxidation with low sludge production were discussed in the OSA process. It has been confirmed that sludge decay is the decisive cause in the OSA process, accounting for 66.7% of sludge production reduction. Sludge decay includes hydrolysis and acidogenesis of dead microorganisms and particle organic carbon adsorbed in sludge floc and endogenous metabolism. By batch experiments, it has been proven that there is energetic uncoupling in the OSA system since microorganisms were exposed to alternative anaerobic and aerobic environment. It accounts for about 7.5% of sludge production reduction. Soluble chemical oxygen demand (SCOD) released from the anaerobic sludge tank in the OSA process was used as the substrate for cryptic growth. The substrate was used for anoxic denitrifying, anaerobic phosphorus release, sulfate reduction, and methane production. These anaerobic reactions in the sludge anaerobic tank have lower sludge production than in the aerobic oxidation when equivalent SCOD is consumed, which may lead to approximately 23% of sludge reduction in the OSA process. It has been concluded that multiple causes resulted in the minimization of excess sludge in the OSA system. The microbial community structure and diversity of sludge samples from the CAS (conventional activated sludge) and OSA systems were investigated by 16 SrDNA PCR-DG-DGGE (polymerase chain reaction-double gradient-denaturing gradient gel electrophoresis). DGGE profile and cluster analysis showed more abundant species in the OSA system contrasting to microbial communities in the CAS system.

Optimization of cold-end system of thermal power plants based on entropy generation minimization

《能源前沿(英文)》 2022年 第16卷 第6期   页码 956-972 doi: 10.1007/s11708-021-0785-5

摘要: Cold-end systems are heat sinks of thermal power cycles, which have an essential effect on the overall performance of thermal power plants. To enhance the efficiency of thermal power plants, multi-pressure condensers have been applied in some large-capacity thermal power plants. However, little attention has been paid to the optimization of the cold-end system with multi-pressure condensers which have multiple parameters to be identified. Therefore, the design optimization methods of cold-end systems with single- and multi-pressure condensers are developed based on the entropy generation rate, and the genetic algorithm (GA) is used to optimize multiple parameters. Multiple parameters, including heat transfer area of multi-pressure condensers, steam distribution in condensers, and cooling water mass flow rate, are optimized while considering detailed entropy generation rate of the cold-end systems. The results show that the entropy generation rate of the multi-pressure cold-end system is less than that of the single-pressure cold-end system when the total condenser area is constant. Moreover, the economic performance can be improved with the adoption of the multi-pressure cold-end system. When compared with the single-pressure cold-end system, the excess revenues gained by using dual- and quadruple-pressure cold-end systems are 575 and 580 k$/a, respectively.

关键词: cold-end system     entropy generation minimization     optimization     economic analysis     genetic algorithm (GA)    

Power system reconfiguration and loss minimization for a distribution systems using “Catfish PSO” algorithm

K Sathish KUMAR,S NAVEEN

《能源前沿(英文)》 2014年 第8卷 第4期   页码 434-442 doi: 10.1007/s11708-014-0313-y

摘要: One of the very important ways to save electrical energy in the distribution system is network reconfiguration for loss reduction. Distribution networks are built as interconnected mesh networks; however, they are arranged to be radial in operation. The distribution feeder reconfiguration is to find a radial operating structure that optimizes network performance while satisfying operating constraints. The change in network configuration is performed by opening sectionalizing (normally closed) and closing tie (normally opened) switches of the network. These switches are changed in such a way that the radial structure of networks is maintained, all of the loads are energized, power loss is reduced, power quality is enhanced, and system security is increased. Distribution feeder reconfiguration is a complex nonlinear combinatorial problem since the status of the switches is non-differentiable. This paper proposes a new evolutionary algorithm (EA) for solving the distribution feeder reconfiguration (DFR) problem for a 33-bus and a 16-bus sample network, which effectively ensures the loss minimization.

关键词: distribution system reconfiguration (DFR)     power loss reduction     catfish particle swarm optimization (catfish PSO)     radial structure    

Robust design approach to the minimization of functional performance variations of products and systems

J. ZHANG, H. DU, D. XUE, P. GU

《机械工程前沿(英文)》 2021年 第16卷 第2期   页码 379-392 doi: 10.1007/s11465-020-0607-1

摘要: Functional performance variations of products and systems are often used to measure the qualities of products and systems considering the changes in the design parameter values caused by uncertainties. A robust design approach has been developed in this research to minimize the functional performance variations considering the design parameter uncertainties by identifying the boundaries of the functional performance variations through optimization. In this work, a mathematical model is developed to describe the relationships among functional performance, design configurations and parameters, and design parameter uncertainties. A multi-level optimization model is established to identify: (1) The optimal design configuration, (2) the optimal values of design parameters, and (3) the boundaries of functional performance variations. Sensitivity analysis considering the impact of parameter uncertainties on functional performance variation boundaries has also been conducted. A case study on the design of a truss system has been conducted. Case study results show that the sensitivities of functional performance variation boundaries to the design parameter uncertainties can be reduced significantly using the new robust design approach.

关键词: product design     robust design     design optimization     uncertainties    

Optimal operation of energy at hydrothermal power plants by simultaneous minimization of pollution and

Homayoun EBRAHIMIAN,Bahman TAHERI,Nasser YOUSEFI

《能源前沿(英文)》 2015年 第9卷 第4期   页码 426-432 doi: 10.1007/s11708-015-0376-4

摘要: The aim of this paper is simultaneous minimization of hydrothermal units to reach the best solution by employing an improved artificial bee colony (ABC) algorithm in a multi-objective function consisting of economic dispatch (ED) considering the valve-point effect and pollution function in power systems in view of the hot water of the hydro system. In this type of optimization problem, all practical constraints of units were taken into account as much as possible in order to comply with the reality. These constraints include the maximum and minimum output power of units, the constraints caused by the balance between supply and demand, the impact of pollution, water balance, uneven production curve considering the valve-point effect and system losses. The proposed algorithm is applied on the studied system, and the obtained results indifferent operating conditions are analyzed. To investigate in various operating conditions, different load profiles in 12 h are taken into account. The obtained results are compared with those of the other methods including the genetic algorithm (GA), the Basu technique, and the improved genetic algorithm. Fast convergence is one of this improved algorithm features.

关键词: practical constraints of units     pollution function     inlet steam valve     up-ramp rate of units     improved ABC algorithm    

Forward osmosis coupled with lime-soda ash softening for volume minimization of reverse osmosis

Jiandong Lu, Shijie You, Xiuheng Wang

《环境科学与工程前沿(英文)》 2021年 第15卷 第1期 doi: 10.1007/s11783-020-1301-6

摘要: Abstract • Forward osmosis (FO) coupled with chemical softening for CCI ROC minimization • Effective removal of scale precursor ions by lime-soda ash softening • Enhanced water recovery from 54% to 86% by mitigation of FO membrane scaling • High-purity CaCO3 was recovered from the softening sludge • Membrane cleaning efficiency of 88.5% was obtained by EDTA for softened ROC Reverse osmosis (RO) is frequently used for water reclamation from treated wastewater or desalination plants. The RO concentrate (ROC) produced from the coal chemical industry (CCI) generally contains refractory organic pollutants and extremely high-concentration inorganic salts with a dissolved solids content of more than 20 g/L contributed by inorganic ions, such as Na+, Ca2+, Mg2+, Cl−, and SO42−. To address this issue, in this study, we focused on coupling forward osmosis (FO) with chemical softening (FO-CS) for the volume minimization of CCI ROC and the recovery of valuable resources in the form of CaCO3. In the case of the real raw CCI ROC, softening treatment by lime-soda ash was shown to effectively remove Ca2+/Ba2+ (>98.5%) and Mg2+/Sr2+/Si (>80%), as well as significantly mitigate membrane scaling during FO. The softened ROC and raw ROC corresponded to a maximum water recovery of 86% and 54%, respectively. During cyclic FO tests (4 × 10 h), a 27% decline in the water flux was observed for raw ROC, whereas only 4% was observed for softened ROC. The cleaning efficiency using EDTA was also found to be considerably higher for softened ROC (88.5%) than that for raw ROC (49.0%). In addition, CaCO3 (92.2% purity) was recovered from the softening sludge with an average yield of 5.6 kg/m3 treated ROC. This study provides a proof-of-concept demonstration of the FO-CS coupling process for ROC volume minimization and valuable resources recovery, which makes the treatment of CCI ROC more efficient and more economical.

关键词: Coal chemical industry     Forward osmosis     Chemical softening     Reverse osmosis concentrate    

基于联邦边缘学习的梯度量化和带宽分配优化策略 Research Article

刘沛西1,3,江甲沫2,朱光旭3,程磊4,5,蒋伟1,罗武1,杜滢2,王志勤2

《信息与电子工程前沿(英文)》 2022年 第23卷 第8期   页码 1247-1263 doi: 10.1631/FITEE.2100538

摘要: 由于边缘设备有限算力和边缘网络有限的无线资源,利用联邦边缘学习(federated edge learning, FEEL)训练机器学习模型通常非常耗时。本文研究了量化FEEL系统中训练时间最小化问题,其中异构边缘设备通过正交信道向边缘服务器发送量化后的梯度。采用随机量化对上传的梯度进行压缩,可减少每轮通信的开销,但可能会增加通信轮数。综合考虑通信时间、计算时间和通信轮数对训练时间进行建模。基于所提出的训练时间模型,描述了通信轮数和每轮延迟之间的内在权衡。具体地,分析了量化FEEL的收敛性。提出一种基于数据模型双驱动的拟合方法以得到精确的最优间隔,并在此基础上得到通信轮数和总训练时间的闭式表达式。在总带宽限制下,将训练时间最小化问题建模为量化级数和带宽分配的优化问题。本文通过交替求解量化优化子问题(通过连续凸近似方法求解)和带宽分配子问题(通过二分查找方法求解)解决这个问题。在不同学习任务和模型下,仿真结果证明了本文分析的有效性和所提优化算法性能接近最优。

关键词: 联邦边缘学习;量化优化;带宽分配;训练时间最小化    

Constriction factor based particle swarm optimization for analyzing tuned reactive power dispatch

Syamasree BISWAS(RAHA), Kamal Krishna MANDAL, Niladri CHAKRABORTY

《能源前沿(英文)》 2013年 第7卷 第2期   页码 174-181 doi: 10.1007/s11708-013-0246-x

摘要: The reactive power dispatch (RPD) problem is a very critical optimization problem of power system which minimizes the real power loss of the transmission system. While solving the said problem, generator bus voltages and transformer tap settings are kept within a stable operating limit. In connection with the RPD problem, solving reactive power is compensated by incorporating shunt capacitors. The particle swarm optimization (PSO) technique is a swarm intelligence based fast working optimization method which is chosen in this paper as an optimization tool. Additionally, the constriction factor is included with the conventional PSO technique to accelerate the convergence property of the applied optimization tool. In this paper, the RPD problem is solved in the case of the two higher bus systems, i.e., the IEEE 57-bus system and the IEEE 118-bus system. Furthermore, the result of the present paper is compared with a few optimization technique based results to substantiate the effectiveness of the proposed study.

关键词: real power loss minimization     voltage stability     constriction factor     particle swarm optimization (PSO)    

Comparison between inhibitor and uncoupler for minimizing excess sludge production of an activated sludge process

CHEN Guowei, XI Pengge, XU Deqian, YU Hanqing

《环境科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 63-66 doi: 10.1007/s11783-007-0012-6

摘要: In order to study the minimization of excess sludge production, the reduction in the excess sludge production in the presence of an inhibitor and uncoupler was studied in this work. The experimental results show that such an addition could effectively reduce the production of excess sludge. With the energy uncoupling model established in this work, energy uncoupling coefficient () was used to evaluate the reduction in excess sludge production. The energy uncoupling coefficients in the presence of dinitrophenol (dNP), Zn, and Cu was 0.75, 0.46, and 0.18, respectively. The analysis demonstrated that energy spilling occurred in the presence of dNP, and that dNP was an effective uncoupler for reducing the production of excess activated sludge without affecting the microbial respiration activity.

关键词: uncoupling coefficient     Cu     minimization     presence     uncoupling    

Development of a hydrodynamic model and the corresponding virtual software for dual-loop circulating fluidized beds

Shanwei Hu, Xinhua Liu

《化学科学与工程前沿(英文)》 2021年 第15卷 第3期   页码 579-590 doi: 10.1007/s11705-020-1953-6

摘要: Dual-loop circulating fluidized bed (CFB) reactors have been widely applied in industry because of their good heat and mass transfer characteristics and continuous handling ability. However, the design of such reactors is notoriously difficult owing to the poor understanding of the underlying mechanisms, meaning it has been heavily based on empiricism and stepwise experiments. Modeling the gas-solid CFB system requires a quantitative description of the multiscale heterogeneity in the sub-reactors and the strong coupling between them. This article proposed a general method for modeling multi-loop CFB systems by utilizing the energy minimization multiscale (EMMS) principle. A full-loop modeling scheme was implemented by using the EMMS model and/or its extension models to compute the hydrodynamic parameters of the sub-reactors, to achieve the mass conservation and pressure balance in each circulation loop. Based on the modularization strategy, corresponding interactive simulation software was further developed to facilitate the flexible creation and fast modeling of a customized multi-loop CFB reactor. This research can be expected to provide quantitative references for the design and scale-up of gas-solid CFB reactors and lay a solid foundation for the realization of virtual process engineering.

关键词: multi-loop circulating fluidized bed     mathematical modeling     energy minimization multiscale     virtual fluidization     mesoscale structure    

Fault classification and reconfiguration of distribution systems using equivalent capacity margin method

K. Sathish KUMAR, T. JAYABARATHI

《能源前沿(英文)》 2012年 第6卷 第4期   页码 394-402 doi: 10.1007/s11708-012-0211-0

摘要: This paper investigates the capability of support vector machines (SVM) for prediction of fault classification and the use of the concept of equivalent capacity margin (ECM) for restoration of the power system. The SVM, as a novel type of machine learning based on statistical learning theory, achieves good generalization ability by adopting a structural risk minimization (SRM) induction principle aimed at minimizing a bound on the generalization error of a model rather than the minimization of the error on the training data only. Here, the SVM has been used as a classification. The inputs of the SVM model are power and voltage values. An equation has been developed for the prediction of the fault in the power system based on the developed SVM model. The next steps of this paper are the restoration and reconfiguration by using the ECM concept, the development of a code, and the testing of the results with various load outages, which have been executed for a 12 load system.

关键词: support vector machines (SVM)     structural risk minimization (SRM)     equivalent capacity margin (ECM)     restoration     fault classification    

图引导正则最小化的随机超梯度的交替方向方法 None

Qiang LAN, Lin-bo QIAO, Yi-jie WANG

《信息与电子工程前沿(英文)》 2018年 第19卷 第6期   页码 755-762 doi: 10.1631/FITEE.1601771

摘要: 提出并比较额外梯度交替方向的几种随机变体方法,称为带拉格朗日函数(SEGL)的随机超梯度交替方向法和带增广拉格朗日函数(SEGAL)的随机超梯度交替方向法。这些方法由两个大规模凸目标函数组成,可最小化图形引导的优化问题。机器学习中一些重要应用遵循图导引优化公式等作为线性回归、逻辑回归、Lasso结构化扩展以及结构化正则化逻辑回归的原则。通过融合逻辑回归和图形引导正则化回归,在几类数据集上进行了试验。试验结果表明所提算法优于其他竞争算法,且在实际应用中,SEGAL比SEGL性能更好。

关键词: 随机优化;图形引导最小化;超梯度法;融合逻辑回归;图导向正则化逻辑回归    

Minimization of total energy consumption in an m-machine flow shop with an exponential time-dependent

Lingxuan LIU, Zhongshun SHI, Leyuan SHI

《工程管理前沿(英文)》 2018年 第5卷 第4期   页码 487-498 doi: 10.15302/J-FEM-2018042

摘要:

This study investigates an energy-aware flow shop scheduling problem with a time-dependent learning effect. The relationship between the traditional and the proposed scheduling problem is shown and objective is to determine a job sequence in which the total energy consumption is minimized. To provide an efficient solution framework, composite lower bounds are proposed to be used in a solution approach with the name of Bounds-based Nested Partition (BBNP). A worst-case analysis on shortest process time heuristic is conducted for theoretical measurement. Computational experiments are performed on randomly generated test instances to evaluate the proposed algorithms. Results show that BBNP has better performance than conventional heuristics and provides considerable computational advantage.

关键词: flow shop     energy-aware scheduling     learning effect     nested partition     worst-case error bound    

结合全变分最小化和稀疏字典学习后处理的低剂量CT重建 Article

Yong DING, Tuo HU

《信息与电子工程前沿(英文)》 2017年 第18卷 第12期   页码 2001-2008 doi: 10.1631/FITEE.1700287

摘要: 随着CT(computed tomography)中过量辐射剂量带来的健康风险日渐引发人们的担忧,低剂量CT得到了大量的关注。然而对于低剂量CT成像而言,在降低剂量的同时保证图像的高质量是一个很大的挑战。相比传统的滤波反投影算法,基于压缩感知的迭代重建法取得了良好的成像效果。但是迭代重建计算复杂度高,阻碍了其临床应用。本文提出一种结合全变分(total variation, TV)最小化和稀疏字典学习的重建方法,不仅提高了重建效果,而且通过自适应的停止策略提高了重建速度。实验结果表明,本文提出的方法相比其他类型的方法能获得更好的图像质量和更高的计算效率。

关键词: 低剂量CT;CT成像;全变分;稀疏字典学习    

标题 作者 时间 类型 操作

Mechanism on minimization of excess sludge in oxic-settling-anaerobic (OSA) process

WANG Jianfang, ZHAO Qingliang, JIN Wenbiao, LIN Jikan

期刊论文

Optimization of cold-end system of thermal power plants based on entropy generation minimization

期刊论文

Power system reconfiguration and loss minimization for a distribution systems using “Catfish PSO” algorithm

K Sathish KUMAR,S NAVEEN

期刊论文

Robust design approach to the minimization of functional performance variations of products and systems

J. ZHANG, H. DU, D. XUE, P. GU

期刊论文

Optimal operation of energy at hydrothermal power plants by simultaneous minimization of pollution and

Homayoun EBRAHIMIAN,Bahman TAHERI,Nasser YOUSEFI

期刊论文

Forward osmosis coupled with lime-soda ash softening for volume minimization of reverse osmosis

Jiandong Lu, Shijie You, Xiuheng Wang

期刊论文

基于联邦边缘学习的梯度量化和带宽分配优化策略

刘沛西1,3,江甲沫2,朱光旭3,程磊4,5,蒋伟1,罗武1,杜滢2,王志勤2

期刊论文

Constriction factor based particle swarm optimization for analyzing tuned reactive power dispatch

Syamasree BISWAS(RAHA), Kamal Krishna MANDAL, Niladri CHAKRABORTY

期刊论文

Comparison between inhibitor and uncoupler for minimizing excess sludge production of an activated sludge process

CHEN Guowei, XI Pengge, XU Deqian, YU Hanqing

期刊论文

Development of a hydrodynamic model and the corresponding virtual software for dual-loop circulating fluidized beds

Shanwei Hu, Xinhua Liu

期刊论文

Fault classification and reconfiguration of distribution systems using equivalent capacity margin method

K. Sathish KUMAR, T. JAYABARATHI

期刊论文

图引导正则最小化的随机超梯度的交替方向方法

Qiang LAN, Lin-bo QIAO, Yi-jie WANG

期刊论文

Minimization of total energy consumption in an m-machine flow shop with an exponential time-dependent

Lingxuan LIU, Zhongshun SHI, Leyuan SHI

期刊论文

结合全变分最小化和稀疏字典学习后处理的低剂量CT重建

Yong DING, Tuo HU

期刊论文