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Temperature-Based Fan Speed Optimization Strategy
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作者 Chucheng Wang Chongyi Luo +3 位作者 Junnian Wei Haiyang Peng Xiaorong Zhong Cai Ye 《Journal of Electronic Research and Application》 2024年第3期135-141,共7页
As energy efficiency and indoor comfort increasingly become key standards in modern residential and office environments,research on intelligent fan speed control systems has become particularly important.This study ai... As energy efficiency and indoor comfort increasingly become key standards in modern residential and office environments,research on intelligent fan speed control systems has become particularly important.This study aims to develop a temperature-feedback-based fan speed optimization strategy to achieve higher energy efficiency and user comfort.Firstly,by analyzing existing fan speed control technologies,their main limitations are identified,such as the inability to achieve smooth speed transitions.To address this issue,a BP-PID speed control algorithm is designed,which dynamically adjusts fan speed based on indoor temperature changes.Experimental validation demonstrates that the designed system can achieve smooth speed transitions compared to traditional fan systems while maintaining stable indoor temperatures.Furthermore,the real-time responsiveness of the system is crucial for enhancing user comfort.Our research not only demonstrates the feasibility of temperature-based fan speed optimization strategies in both theory and practice but also provides valuable insights for energy management in future smart home environments.Ultimately,this research outcome will facilitate the development of smart home systems and have a positive impact on environmental sustainability. 展开更多
关键词 Smart temperature control Fan speed optimization Temperature feedback control dynamic speed adjustment Smart home systems Energy-saving technology
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Dynamic Optimization of Handover Parameters Adjustment for Conflict Avoidance in Long Term Evolution 被引量:2
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作者 李云 李曼 +2 位作者 曹傧 王勇 刘文晶 《China Communications》 SCIE CSCD 2013年第1期56-71,共16页
In order to achieve dynamical optimization of mobility load balancing,we analyze the conflict between mobility load balancing and mobility robustness optimization caused by the improper operation of handover parameter... In order to achieve dynamical optimization of mobility load balancing,we analyze the conflict between mobility load balancing and mobility robustness optimization caused by the improper operation of handover parameters.To this end,a method of Handover Parameters Adjustment for Conflict Avoidance(HPACA)is proposed.Considering the movement of users,HPCAC can dynamically adjust handover range to optimize the mobility load balancing.The movement of users is an important factor of handover,which has a dramatic impact on system performance.The numerical evaluation results show the proposed approach outperforms the existing method in terms of throughput,call blocking ratio,load balancing index,radio link failure ratio,ping-pong handover ratio and call dropping ratio. 展开更多
关键词 Long Term Evolution self-organizing network dynamically adjusting handover range time to trigger hysteresisparameter
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Dynamic capacity balance between stripping and mining of a dragline stripping system 被引量:1
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作者 Shuangshuang Xiao Guowei Dong Hongsheng Wang 《International Journal of Coal Science & Technology》 EI 2020年第2期380-387,共8页
The reliability factors of a dragline stripping system were analyzed using system reliability theory to improve its reliability and ensure the stability of surface coal mine production.The relationship between the dra... The reliability factors of a dragline stripping system were analyzed using system reliability theory to improve its reliability and ensure the stability of surface coal mine production.The relationship between the dragline scheduled stripping volume with both the weighted average thickness of the coal seam and the height of the blast casting bench was derived.The results show that the reliability of the dragline stripping system decreases with the weighted average thickness of the coal seam and increases with a reduced casting blast bench height and monthly raw coal production capacity.Furthermore,the dynamic monthly advance distance of the dragline stripping system was found,a new concept of the dragline stripping system reliability and measurement methodology were proposed,and a prediction model for the dragline production capacity was established using a generalized regression neural network.In addition,the steps and processes of the reliability were improved.The study on the Heidaigou surface mine shows that the height of the casting blast bench should be reduced to 10.5 m when its raw coal production capacity is improved from 20 to 30 Mt/a.During the normal production of surface coal,the system reliability can be improved by dynamically determining the weighted average coal seam thickness,accurately predicting the dragline production capacity,and taking other corresponding measures. 展开更多
关键词 Surface mine Stripping technology RELIABILITY dynamic adjustment
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Dynamic changes of cellular immune function and individualized adjustments of immunosup-pressant for the management of severe infection after liver transplantation
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作者 李瑞东 《外科研究与新技术》 2011年第4期276-276,共1页
Objective To explore the dynamic changes of the cellular immune function in severe infection after liver transplantation,and to guide the individualized immunology adjustment. Methods 378 cases of liver transplantatio... Objective To explore the dynamic changes of the cellular immune function in severe infection after liver transplantation,and to guide the individualized immunology adjustment. Methods 378 cases of liver transplantation were analyzed retrospectively. Seventy - four cases ( infection group) suffered serious infection,including 54 cases cured ( cure group) ,20 cases died ( 展开更多
关键词 than dynamic changes of cellular immune function and individualized adjustments of immunosup-pressant for the management of severe infection after liver transplantation
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A NEW SOLUTION MODEL OF NONLINEAR DYNAMIC LEAST SQUARE ADJUSTMENT
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作者 陶华学 郭金运 《Journal of Coal Science & Engineering(China)》 2000年第2期47-51,共5页
The nonlinear least square adjustment is a head object studied in technology fields. The paper studies on the non derivative solution to the nonlinear dynamic least square adjustment and puts forward a new algorithm m... The nonlinear least square adjustment is a head object studied in technology fields. The paper studies on the non derivative solution to the nonlinear dynamic least square adjustment and puts forward a new algorithm model and its solution model. The method has little calculation load and is simple. This opens up a theoretical method to solve the linear dynamic least square adjustment. 展开更多
关键词 nonlinear least square dynamic adjustment non derivative analytic method
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Bioinspired 4D Printing Shape-Memory Polyurethane Rhinoplasty Prosthesis for Dynamic Aesthetic Adjustment
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作者 Jiaqi Liu Guiwei Li +5 位作者 He Liu Jincheng Wang Hui Wang Xue Gao Qingping Liu Chenyu Wang 《Journal of Bionic Engineering》 SCIE EI CSCD 2024年第3期1397-1411,共15页
The disparity between the postoperative outcomes of rhinoplasty and the expected results frequently necessitates secondary or multiple surgeries as a compensatory measure,greatly diminishing patient satisfaction.Howev... The disparity between the postoperative outcomes of rhinoplasty and the expected results frequently necessitates secondary or multiple surgeries as a compensatory measure,greatly diminishing patient satisfaction.However,there is renewed optimism for addressing these challenges through the innovative realm of Four-Dimensional(4D)printing.This groundbreaking technology enables three-dimensional objects with shape-memory properties to undergo predictable transformations under specific external stimuli.Consequently,implants crafted using 4D printing offer significant potential for dynamic adjustments.Inspired by worms in our research,we harnessed 4D printing to fabricate a Shape-Memory Polyurethane(SMPU)for use as a nasal augmentation prosthesis.The choice of SMPU was guided by its Glass Transition Temperature(Tg),which falls within the acceptable temperature range for the human body.This attribute allowed for temperature-responsive intraoperative self-deformation and postoperative remodeling.Our chosen animal model for experimentation was rabbits.Taking into account the anatomical structure of the rabbit nose,we designed and produced nasal augmentation prostheses with superior biocompatibility.These prostheses were then surgically implanted in a minimally invasive manner into the rabbit noses.Remarkably,they exhibited successful temperature-controlled in-surgery self-deformation according to the predetermined shape and non-invasive remodeling within a mere 9 days post-surgery.Subsequent histological evaluations confirmed the practical viability of these prostheses in a living organism.Our research findings posit that worm-inspired 4D-printed SMPU nasal prostheses hold significant promise for achieving dynamic aesthetic adjustments. 展开更多
关键词 4D printing Shape memory polyurethane RHINOPLASTY Self-deformation dynamic aesthetic adjustment
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Assessment of Operational Performance in a Power Generation/Selling Integrated Company Using a Dynamic Proportional Adjustment Coefficient
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作者 Jingbin Wu Hongming Yang Sheng Xiang 《Energy Engineering》 EI 2024年第11期3263-3287,共25页
Currently,the operational performance assessment system in the power market primarily focuses on power generation and electricity retail companies,lacking a system tailored to the operational characteristics of power ... Currently,the operational performance assessment system in the power market primarily focuses on power generation and electricity retail companies,lacking a system tailored to the operational characteristics of power generation/selling integrated companies.Therefore,this article proposes an assessment index system for assessing the operational performance of a power generation/selling integrated company,encompassing three dimensions:basic capacity,development potential,and external environment.A dynamic proportional adjustment coefficient is designed,along with a subjective and objective weighting model for assessment indexes based on a combined weightingmethod.Subsequently,the operational performance of an integrated company is assessed using extension theory.The results in the case study demonstrate the feasibility and effectiveness of the proposed dynamic proportional adjustment coefficient. 展开更多
关键词 Power generation/selling integrated company dynamic proportional adjustment coefficient combined weighting extension theory assessment of operational performance
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Approach to inter-satellite time synchronization for micro-satellite cluster 被引量:8
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作者 XU Jiuling ZHANG Chaojie +1 位作者 WANG Chunhui JIN Xiaojun 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第4期805-815,共11页
Micro-satellite cluster enables a whole new class of missions for communications, remote sensing, and scientific research for both civilian and military purposes. Synchronizing the time of the satellites in a cluster ... Micro-satellite cluster enables a whole new class of missions for communications, remote sensing, and scientific research for both civilian and military purposes. Synchronizing the time of the satellites in a cluster is important for both cluster sensing capabilities and its autonomous operating. However, the existing time synchronization methods are not suitable for microsatellite cluster, because it requires too many human interventions and occupies too much ground control resource. Although, data post-process may realize the equivalent time synchronization, it requires processing time and powerful computing ability on the ground, which cannot be implemented by cluster itself. In order to autonomously establish and maintain the time benchmark in a cluster, we propose a compact time difference compensation system(TDCS), which is a kind of time control loop that dynamically adjusts the satellite reference frequency according to the time difference. Consequently, the time synchronization in the cluster can be autonomously achieved on-orbit by synchronizing the clock of other satellites to a chosen one's. The experimental result shows that the standard deviation of time synchronization is about 102 ps when the carrier to noise ratio(CNR) is 95 d BHz, and the standard deviation of corresponding frequency difference is approximately0.36 Hz. 展开更多
关键词 time difference measurement time synchronization dynamical reference frequency adjustment micro-satellite cluster
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Scheduling transactions in mobile distributed real-time database systems 被引量:1
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作者 雷向东 赵跃龙 +1 位作者 陈松乔 袁晓莉 《Journal of Central South University of Technology》 EI 2008年第4期545-551,共7页
A DMVOCC-MVDA (distributed multiversion optimistic concurrency control with multiversion dynamic adjustment) protocol was presented to process mobile distributed real-time transaction in mobile broadcast environment... A DMVOCC-MVDA (distributed multiversion optimistic concurrency control with multiversion dynamic adjustment) protocol was presented to process mobile distributed real-time transaction in mobile broadcast environments. At the mobile hosts, all transactions perform local pre-validation. The local pre-validation process is carried out against the committed transactions at the server in the last broadcast cycle. Transactions that survive in local pre-validation must be submitted to the server for local final validation. The new protocol eliminates conflicts between mobile read-only and mobile update transactions, and resolves data conflicts flexibly by using multiversion dynamic adjustment of serialization order to avoid unnecessary restarts of transactions. Mobile read-only transactions can be committed with no-blocking, and respond time of mobile read-only transactions is greatly shortened. The tolerance of mobile transactions of disconnections from the broadcast channel is increased. In global validation mobile distributed transactions have to do check to ensure distributed serializability in all participants. The simulation results show that the new concurrency control protocol proposed offers better performance than other protocols in terms of miss rate, restart rate, commit rate. Under high work load (think time is ls) the miss rate of DMVOCC-MVDA is only 14.6%, is significantly lower than that of other protocols. The restart rate of DMVOCC-MVDA is only 32.3%, showing that DMVOCC-MVDA can effectively reduce the restart rate of mobile transactions. And the commit rate of DMVOCC-MVDA is up to 61.2%, which is obviously higher than that of other protocols. 展开更多
关键词 mobile distributed real-time database systems muliversion optimistic concurrency control multiversion dynamic adjustment pre-validation multiversion data broadcast
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An Ensemble Application of Conflict-Resolving ART-Based Neural Networks to Fault Detection and Diagnosis 被引量:1
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作者 Shing-chiang TAN Chee-peng LIM 《Journal of Measurement Science and Instrumentation》 CAS 2011年第4期371-377,共7页
Accurate fault detection and diagnosis is important for secure and profitable operation of modern power systems.In this paper,an ensemble of conflict-resolving Fuzzy ARTMAP classifiers,known as Probabilistic Multiple ... Accurate fault detection and diagnosis is important for secure and profitable operation of modern power systems.In this paper,an ensemble of conflict-resolving Fuzzy ARTMAP classifiers,known as Probabilistic Multiple Fuzzy ARTMAP with Dynamic Decay Adjustment(PMFAMDDA),for accurate discrimination between normal and faulty operating conditions of a Circulating Water(CW)system in a power generation plant is proposed.The decisions of PMFAMDDA are reached through a probabilistic plurality voting strategy that is in agreement with the Bayesian theorem.The results of the proposed PMFAMDDA model are compared with those from an ensemble of Probabilistic Multiple Fuzzy ARTMAP(PMFAM)classifiers.The outcomes reveal that PMFAMDDA,in general,outperforms PMFAM in discriminating operating conditions of the CW system. 展开更多
关键词 fault detection and diagnosis fuzzy ARTMAP dynamic decay adjustment algorithm pluralityvoting circulating water system
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An Empirical Analysis on the Stable Return of Resident Funds
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作者 Jinling He Zixiang Xia +1 位作者 Jingcheng He Xin Gao 《Proceedings of Business and Economic Studies》 2021年第4期128-138,共11页
This paper mainly studies how investors invest in funds to obtain high returns while avoiding risks.Firstly,from the perspective of portfolio investment,this paper introduces the traditional Markowitz mean-variance mo... This paper mainly studies how investors invest in funds to obtain high returns while avoiding risks.Firstly,from the perspective of portfolio investment,this paper introduces the traditional Markowitz mean-variance model and capital asset pricing model(CAPM),then selects four funds from different industries by MATLAB program in Sina Finance and Economics Network for application analysis from which the optimal portfolio point can be obtained under the combination of efficient frontier and capital allocation line.Subsequently,by analyzing the returns of long-term holdings and short-term operations of Noan Growth Hybrid Fund,it is confirmed that long-term holding funds can better cope with the changing market so as to obtain more stable returns.Finally,this paper discusses the dynamic adjustments of asset portfolio.Resident investors are supposed to take into account the market situation and the changes of the fund itself to adjust the holding fund portfolio.Based on the research in this paper,resident investors ought to combine investment funds to diversify risk allocation and make long-term holding plans according to their risk tolerance.At the same time,they should also make appropriate dynamic adjustments when the external environment changes to ensure long-term benefits. 展开更多
关键词 Portfolio investment Mean-variance model Long-term investment CAPM dynamic adjustment
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Plotinus:A Satellite Internet Digital Twin System
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作者 Yue Gao Kun Qiu +6 位作者 Zhe Chen Wenjun Zhu Qi Zhang Handong Luo Quanwei Lin Ziheng Yang Wenhao Liu 《Journal of Communications and Information Networks》 EI CSCD 2024年第1期24-33,共10页
The development of space-air-ground integrated networks (SAGIN) requires sophisticated satellite Internet emulation tools that can handle complex, dynamic topologies and offer in-depth analysis. Existing emulation pla... The development of space-air-ground integrated networks (SAGIN) requires sophisticated satellite Internet emulation tools that can handle complex, dynamic topologies and offer in-depth analysis. Existing emulation platforms struggle with challenges like the need for detailed implementation across all network layers, real-time response, and scalability. This paper proposes a digital twin system based on microservices for satellite Internet emulation,namely Plotinus,which aims to solve these problems. Plotinus features a modular design, allowing for easy replacement of the physical layer to emulate different aerial vehicles and analyze channel interference. It also enables replacing of path computation methods to simplify testing and deploying algorithms. In particular, Plotinus allows for real-time emulation with live network traffic,enhancing practical network models. The evaluation result shows Plotinus’s effective emulation of dynamic satellite networks with real-world devices. Its adaptability for various communication models and algorithm testing highlights Plotinus’s role as a vital tool for developing and analyzing SAGIN systems, offering a cross-layer,real-time,and scalable digital twin system. 展开更多
关键词 network emulation framework dynamic topology adjustment microservice architecture
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Dynamic Transition of Exchange Rate Regime in China 被引量:1
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作者 Naoyuki Yoshino Sahoko Kaji Tamon Asonuma 《China & World Economy》 SCIE 2014年第3期36-55,共20页
Thepaper considers the optimal transition path for China's exchange rate regime. How can China successfully make the shift from the current dollar peg regime to a more desirable regime, whether a basket peg or a flo... Thepaper considers the optimal transition path for China's exchange rate regime. How can China successfully make the shift from the current dollar peg regime to a more desirable regime, whether a basket peg or a floating regime? To answer this question, we develop a dynamic small open economy general equilibrium model. We construct four transition policies based on a basket peg or a floating regime and compare the welfare gains of these policies relative to maintaining the dollar peg regime. Two main results are derived from the quantitative analysis using Chinese data from 1999Q1 to 2010Q4. First, following a gradual adjustment to a basket peg regime is the most appropriate path for China to take, with minimal welfare losses associated with the shift in the exchange rate regime. Second, a sudden shift to the basket peg is the second best solution, and is superior to a sudden shift to floating because the monetary authority can efficiently determine optimal weights to attach to currencies in the basket to achieve policy goals once they adopt a basket peg regime. 展开更多
关键词 Chinese renminbi Chinese exchange rate regime dynamic adjustment transition path
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A new dynamic bacterial foraging optimization and its application on model reduction
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作者 Shenli Wu Sun’an Wang Xiaohu Li 《International Journal of Modeling, Simulation, and Scientific Computing》 EI 2015年第2期107-131,共25页
Inspired by the foraging behavior of E.coli bacteria,bacterial foraging optimization(BFO)has emerged as a powerful technique for solving optimization problems.However,BFO shows poor performance on complex and high-dim... Inspired by the foraging behavior of E.coli bacteria,bacterial foraging optimization(BFO)has emerged as a powerful technique for solving optimization problems.However,BFO shows poor performance on complex and high-dimensional optimization problems.In order to improve the performance of BFO,a new dynamic bacterial foraging optimization based on clonal selection(DBFO-CS)is proposed.Instead of fixed step size in the chemotaxis operator,a new piecewise strategy adjusts the step size dynamically by regulatory factor in order to balance between exploration and exploitation during optimization process,which can improve convergence speed.Furthermore,reproduction operator based on clonal selection can add excellent genes to bacterial populations in order to improve bacterial natural selection and help good individuals to be protected,which can enhance convergence precision.Then,a set of benchmark functions have been used to test the proposed algorithm.The results show that DBFO-CS offers significant improvements than BFO on convergence,accuracy and robustness.A complex optimization problem of model reduction on stable and unstable linear systems based on DBFO-CS is presented.Results show that the proposed algorithm can efficiently approximate the systems. 展开更多
关键词 Bacterial foraging optimization dynamic adjustment clonal selection model reduction
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Dynamics of financial leverage across firm life cycle in Chinese firms:An empirical investigation using dynamic panel data model
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作者 Ajid ur Rehman Wang Man Yu Haoyang 《China Finance and Economic Review》 2017年第1期27-55,共29页
This study tries to investigate how firms adjust their leverage policy across the firm’s life cycle.For this purpose the study uses an extensive set of data of 867 A listed Chinese non-financial firms over a 19-year ... This study tries to investigate how firms adjust their leverage policy across the firm’s life cycle.For this purpose the study uses an extensive set of data of 867 A listed Chinese non-financial firms over a 19-year years period(1996-2014).The study employs Arellano-Bover/Blundell-Bond dynamic panel data model to estimate adjustment rate of leverage and its determinants in three different life stages of Chinese firms.We find that adjustment rate of leverage varies for different life stages.In accordance with trade off theory of capital structure this study reports a low-high-low pattern of leverage across growth,maturity and decline stage of firms’life respectively.For total leverage,dynamic panel data reports highest adjustment rate for growing firms,followed by mature firms and firms in declining stage of their life.Both short term and long term leverage report similar pattern of leverage’s adjustment rate across the three stages of life cycle.The study provides useful insight in a unique market setting of Chinese financial markets. 展开更多
关键词 firm life cycle leverage Chinese firms dynamic adjustment GMM
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Fully Distributed Risk-based Robust Reserve Scheduling for Bulk Hybrid AC-DC Systems
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作者 Zhe Chen Shufeng Dong +2 位作者 Chuangxin Guo Yi Ding Hangyin Mao 《CSEE Journal of Power and Energy Systems》 SCIE EI CSCD 2023年第2期634-644,共11页
To enhance the cost-effectiveness of bulk hybrid AC-DC power systems and promote wind consumption,this paper proposes a two-stage risk-based robust reserve scheduling(RRRS)model.Different from traditional robust optim... To enhance the cost-effectiveness of bulk hybrid AC-DC power systems and promote wind consumption,this paper proposes a two-stage risk-based robust reserve scheduling(RRRS)model.Different from traditional robust optimization,the proposed model applies an adjustable uncertainty set rather than a fixed one.Thereby,the operational risk is optimized together with the dispatch schedules,with a reasonable admissible region of wind power obtained correspondingly.In addition,both the operational base point and adjustment capacity of tielines are optimized in the RRRS model,which enables reserve sharing among the connected areas to handle the significant wind uncertainties.Based on the alternating direction method of multipliers(ADMM),a fully distributed framework is presented to solve the RRRS model in a distributed way.A dynamic penalty factor adjustment strategy(DPA)is also developed and applied to enhance its convergence properties.Since only limited information needs to be exchanged during the solution process,the communication burden is reduced and regional information is protected.Case studies on the 2-area 12-bus system and 3-area 354-bus system illustrate the effectiveness of the proposed model and approach. 展开更多
关键词 dynamic penalty factor adjustment strategy fully distributed framework hybrid AC-DC systems reserve scheduling RISK robust optimization
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Decomposition-Based Multi-Objective Optimization for Energy-Aware Distributed Hybrid Flow Shop Scheduling with Multiprocessor Tasks 被引量:23
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作者 Enda Jiang Ling Wang Jingjing Wang 《Tsinghua Science and Technology》 SCIE EI CAS CSCD 2021年第5期646-663,共18页
This paper addresses the Energy-Aware Distributed Hybrid Flow Shop Scheduling Problem with Multiprocessor Tasks(EADHFSPMT)by considering two objectives simultaneously,i.e.,makespan and total energy consumption.It cons... This paper addresses the Energy-Aware Distributed Hybrid Flow Shop Scheduling Problem with Multiprocessor Tasks(EADHFSPMT)by considering two objectives simultaneously,i.e.,makespan and total energy consumption.It consists of three sub-problems,i.e.,job assignment between factories,job sequence in each factory,and machine allocation for each job.We present a mixed inter linear programming model and propose a Novel MultiObjective Evolutionary Algorithm based on Decomposition(NMOEA/D).We specially design a decoding scheme according to the characteristics of the EADHFSPMT.To initialize a population with certain diversity,four different rules are utilized.Moreover,a cooperative search is designed to produce new solutions based on different types of relationship between any solution and its neighbors.To enhance the quality of solutions,two local intensification operators are implemented according to the problem characteristics.In addition,a dynamic adjustment strategy for weight vectors is designed to balance the diversity and convergence,which can adaptively modify weight vectors according to the distribution of the non-dominated front.Extensive computational experiments are carried out by using a number of benchmark instances,which demonstrate the effectiveness of the above special designs.The statistical comparisons to the existing algorithms also verify the superior performances of the NMOEA/D. 展开更多
关键词 distributed hybrid flow shop multiprocessor tasks energy-aware scheduling multi-objective optimization DECOMPOSITION dynamic adjustment strategy
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Utility water supply forecast via a GM (1,1) weighted Markov chain 被引量:3
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作者 Yi-mei TIAN Hai-liang SHEN +1 位作者 Li ZHANG Xiang-rui LV 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2010年第9期677-682,共6页
This paper describes the procedure of using the GM (1,1) weighted Markov chain (GMWMC) to forecast the utility water supply, a quantity that usually has significant temporal variability. The GMWMC is formulated into f... This paper describes the procedure of using the GM (1,1) weighted Markov chain (GMWMC) to forecast the utility water supply, a quantity that usually has significant temporal variability. The GMWMC is formulated into five steps: (1) use GM (1,1) to fit the trend of the data, and obtain the relative error of the fitted values; (2) divide the relative error into ‘state’ data based on pre-set intervals; (3) calibrate the weighted Markov chain model: herein the parameters are the pre-set interval and the step of transition matrix (TM); (4) by using auto-correlation coefficient as the weight, the Markov chain provides the prediction interval. Then the mid-value of the interval is selected as the relative error for the data. Upon combining the data and its relative error, the predicted magnitude in a specific time period is obtained; and, (5) validate the model. Commonly, static intervals are used in both model calibration and validation stages, usually causing large errors. Thus, a dynamic adjustment interval (DAI) is proposed for a better performance. The proposed procedure is described and demonstrated through a case study, which shows that the DAI can usually achieve a better performance than the static interval, and the best TM may exist for certain data. 展开更多
关键词 dynamic adjustment interval (DAI) FORECAST GM (1 1) Markov chain Water supply
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How and Why Do Firms Adjust Their Cash Holdings toward Targets? Evidence from China 被引量:5
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作者 Yujun Lian Yan Xu Kaiguo Zhou 《Frontiers of Business Research in China》 2012年第4期527-560,共34页
We examine the dynamic adjustment of cash holdings of publicly traded Chinese firms during 1998-2006. The empirical evidence is supportive of the dynamic trade-off theory of cash holdings. In particular, there is stro... We examine the dynamic adjustment of cash holdings of publicly traded Chinese firms during 1998-2006. The empirical evidence is supportive of the dynamic trade-off theory of cash holdings. In particular, there is strong evidence of asymmetric adjustments, i.e., adjustments from above the target are significantly faster than those from below. Moreover, the speeds of adjustment (SOA) are heterogeneous for firms facing differential adjustment costs. More specifically, the adjustment speed is higher in firms with bank lines of credit, positively related to the deviation from the target, but it is negatively related to firm size. Furthermore, in terms of adjustment method, firms make adjustments to their targets primarily through debt and equity financing when they are in cash shortage, On the other hand, the dividend payments play a minimal role in it. Lastly, in terms of motives for adjustment, we find that the precautionary motive arising from financial constraints well explains the cash holdings adjustment behaviors of Chinese listed firms. 展开更多
关键词 cash holding dynamic trade-off theory dynamic adjustment China
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Adaptive watermark generation mechanism based on time series prediction for stream processing 被引量:1
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作者 Yang SONG Yunchun LI +3 位作者 Hailong YANG Jun XU Zerong LUAN Wei LI 《Frontiers of Computer Science》 SCIE EI CSCD 2021年第6期59-73,共15页
The data stream processing framework processes the stream data based on event-time to ensure that the request can be responded to in real-time.In reality,streaming data usually arrives out-of-order due to factors such... The data stream processing framework processes the stream data based on event-time to ensure that the request can be responded to in real-time.In reality,streaming data usually arrives out-of-order due to factors such as network delay.The data stream processing framework commonly adopts the watermark mechanism to address the data disorderedness.Watermark is a special kind of data inserted into the data stream with a timestamp,which helps the framework to decide whether the data received is late and thus be discarded.Traditional watermark generation strategies are periodic;they cannot dynamically adjust the watermark distribution to balance the responsiveness and accuracy.This paper proposes an adaptive watermark generation mechanism based on the time series prediction model to address the above limitation.This mechanism dynamically adjusts the frequency and timing of watermark distribution using the disordered data ratio and other lateness properties of the data stream to improve the system responsiveness while ensuring acceptable result accuracy.We implement the proposed mechanism on top of Flink and evaluate it with realworld datasets.The experiment results show that our mechanism is superior to the existing watermark distribution strategies in terms of both system responsiveness and result accuracy. 展开更多
关键词 data stream processing WATERMARK time series based prediction dynamic adjustment
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