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Distributionally robust optimization based chance-constrained energy management for hybrid energy powered cellular networks

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Digital Communications and Networks 2023年第3期9卷 797-808页

作者： pengfei du Hongjiang Lei Imran Shafique Ansari Jianbo du Xiaoli Chu The Engineering Research Center of Intelligent Air-ground Integrated Vehicle and Traffic Control Ministry of EducationXihua UniversityChengdu610039China Chongqing Key Lab of Mobile Communications Technology Chongqing University of Posts and TelecommunicationsChongqing400065China James Watt School of Engineering University of GlasgowGlasgowG128QQUK Shaanxi Key Laboratory of Information Communication Network and Security Xi'an University of Posts and TelecommunicationsXi'an710121China Electronic and Electrical Engineering University of SheffieldSheffieldS102TNUK

Energy harvesting has been recognized as a promising technique with which to effectively reduce carbon emis-sions and electricity expenses of base ***,renewable energy is inherently stochastic and inter-mittent,imposing formidable challenges on reliably satisfying users'time-varying wireless traffic *** addition,the probability distribution of the renewable energy or users’wireless traffic demand is not always fully known in *** this paper,we minimize the total energy cost of a hybrid-energy-powered cellular network by jointly optimizing the energy sharing among base stations,the battery charging and discharging rates,and the energy purchased from the grid under the constraint of a limited battery size at each base *** solving the formulated non-convex chance-constrained stochastic optimization problem,a new ambiguity set is built to characterize the uncertainties in the renewable energy and wireless traffic demands according to interval sets of the mean and *** this ambiguity set,the original optimization problem is transformed into a more tractable second-order cone programming problem by exploiting the distributionally robust optimization ***,a low-complexity distributionally robust chance-constrained energy management algo-rithm,which requires only interval sets of the mean and covariance of stochastic parameters,is *** results of extensive simulation are presented to demonstrate that the proposed algorithm outperforms existing methods in terms of the computational complexity,energy cost,and reliability.

关键词： Cellular networks Energy harvesting Energy management Chance-constrained Distributionally robust optimization

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Water environment security indicator system for urban water management

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Frontiers of Environmental Science & Engineering 2012年第5期6卷 678-691页

作者： Tian HAO pengfei du Yun GAO School of Environment Tsinghua UniversityBeijing 100084China

Water environment security （WES） is defined in terms of three aspects： first, that it meets basic demands due to industrial and domestic usage; second, that it protects public health from acute and chronic threats; and third, that measures are adopted to ensure sustainable ecological functioning of freshwater resources. Limitations associated with current water environment security indicators in China -- including inefficiency in terms of environmental monitoring, inappropriate indicators and parameters that do not take sufficient account of local water characteristics, and a lack of management targets -- leads to a failure of effective water management. To achieve better water environment management, a systema- tic approach, encompassing several steps including estab- lish ideal indicator system and narrow down the scope, screen priority pollutants, identify local characteristics and organize discussion workshop, should be followed to establish a comprehensive water environment indicator system. A case study in Suzhou is included to demonstrate the detailed operational procedures used to assess the risks associated with poor management practices relating to water environment security as well as design an appro- priate water environment security indicator system.

关键词： water environment security supervision andmanagement monitoring parameter indicator system,Suzhou

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A modeling system for drinking water sources and its application to Jiangdong Reservoir in Xiamen city

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Frontiers of Environmental Science & Engineering 2013年第5期7卷 735-745页

作者： pengfei du Zhiyi LI Jinliang HUANG State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China Coastal & Ocean Management Institute Xiamen University Xiamen 361005 China

Drinking water sources are highly valued by authorities for safeguarding the life of a city. Models are widely applied as important and effective tools in the management of water sources. However, it is difficult to apply models in water source management because water managers are often not equipped with the professional knowledge and operational skills necessary for making use of the models. This paper introduces a drinking water source simulation and prediction system that consists of a watershed model, a hydrological model and a water quality model. This system provides methods and technical guidance for the conventional management of water sources and emergency water event response. In this study, the sub-models of the system were developed based on the data of the Jiangdong Reservoir in Xiamen, and the model validation was based on local monitoring data. The hydrological model and water quality model were integrated by computer programming, and the watershed model was indirectly integrated into the system through a network platform. Furthermore, three applications for Jiangdong Reservoir water protection utilizing the system were introduced in this paper, including a conventional simulation, an emergency simulation, and an emergency measures evaluation.

关键词： water source integrated modeling system,prediction Jiulong River

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Uncertainties in stormwater runoff data collection from a small urban catchment, Southeast China

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Journal of Environmental Sciences 2010年第11期22卷 1703-1709页

作者： Jinliang Huan Zhenshun Tu pengfei du Jie Lin Qingsheng Li Environmental Science Research Center Xiamen University Xiamen 361005 China. Department of Environmental Science and Engineering Tsinghua University Beijing 100084 China Fujian Institute of Oceanography Xiamen 361012 China

Monitoring data are often used to identify stormwater runoff characteristics and in stormwater runoff modelling without consideration of their inherent uncertainties. Integrated with discrete sample analysis and error propagation analysis, this study attempted to quantify the uncertainties of discrete chemical oxygen demand （COD）, total suspended solids （TSS） concentration, stormwater flowrate, stormwater event volumes, COD event mean concentration （EMC）, and COD event loads in terms of flow measurement, sample collection, storage and laboratory analysis. The results showed that the uncertainties due to sample collection, storage and laboratory analysis of COD from stormwater runoff are 13.99%, 19.48% and 12.28%. Meanwhile, flow measurement uncertainty was 12.82%, and the sample collection uncertainty of TSS from stormwater runoff was 31.63%. Based on the law of propagation of uncertainties, the uncertainties regarding event flow volume, COD EMC and COD event loads were quantified as 7.03%, 10.26% and 18.47%.

关键词： urban stormwater runoff in-situ monitoring data uncertainty data collection

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Energy-efficient task offloading, load balancing, and resource allocation in mobile edge computing enabled IoT networks

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Science China(Information Sciences) 2019年第2期62卷 243-245页

作者： Shulei LI Daosen ZHAI pengfei du Ting HAN Tianyuan Ruixin Communication Technology Co.Ltd. School of Electronics and Information Northwestern Polytechnical University The 10th Institute of China Electronics Technology Group Corporation (CETC) The 504th Institute of China Space Technology

Dear editor,The constraints on energy supply for smart mobile devices (SMDs) have obstructed the development of IoT. Mobile edge computing (MEC)[1]is a promising way to overcome the abovementioned challenge, whereby MEC servers (MECSs)can provide computing capabilities to SMDs with superior computing capabilities and thus reduce the energy consumption (EC) for SMDs [1].

关键词： IoT SMD MEC and resource allocation in mobile edge computing enabled IoT networks load balancing Energy-efficient task offloading

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Microstructure design using graphs

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npj Computational Materials 2018年第1期4卷 239-245页

作者： pengfei du Adrian Zebrowski Jaroslaw Zola Baskar Ganapathysubramanian Olga Wodo Department of Mechanical Engineering Iowa State UniversityAmesIAUSA Department of Mechanical and Aerospace Engineering University at BuffaloBuffaloNYUSA Department of Computer Science and Engineering University at BuffaloBuffaloUSA Department of Materials Design and Innovation University at BuffaloBuffaloNYUSA

Thin films with tailored microstructures are an emerging class of materials with applications such as battery electrodes,organic electronics,and *** thin film devices typically exhibit a multi-phase microstructure that is confined,and show large *** approaches to microstructure design focus on optimizing bulk properties,by tuning features that are statistically averaged over a representative ***,we report a tool for morphogenesis posed as a graph-based optimization problem that evolves microstructures recognizing confinement and anisotropy *** illustrate the approach by designing optimized morphologies for photovoltaic applications,and evolve an initial morphology into an optimized morphology exhibiting substantially improved short circuit current(68% improvement over a conventional bulk-heterojunction morphology).We show optimized morphologies across a range of thicknesses exhibiting self-similar *** suggest that thicker films(250 nm)can be used to harvest more incident *** graph based morphogenesis is broadly applicable to microstructure-sensitive design of batteries,biosensors and related applications.

关键词： microstructure Microstructure evolve

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Modeling agricultural non-point source pollution in a high-precipitation coastal area of China

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Frontiers of Environmental Science & Engineering 2014年第6期8卷 922-928页

作者： Zhiyi LI pengfei du Haiwei HUANG Yong Ge Xu LI State Key Joint Laboratory of Environment Simulation and Pollution Control School of Enviromnent Tsinghua University Beijing 100084 China

Non-point source （NPS） pollution simulation in the high-precipitation coastal areas of China is difficult because varying annual typhoon incidence leads to highly contrasting rainfall patterns in dry years and wet years. An IMPULSE （Integrated Model of Non-point Sources Pollution Processes） based NPS model of the Changtan Reservoir watershed, which is a typical high-precipitation coastal area in China, was established based on the analysis of point and NPS pollution data, a digital elevation model, and data on land-use, soil, meteorology, economy, and agricultural management practice. Pre-processed pre-rain- fall soil moisture levels were introduced during the simulation to model the effects of typhoons on hydrology. Rainfall events were simulated sequentially through the year and the model was calibrated and verified using hydrological and water quality data. Accuracy of the simulated rainfall runoff and water quality in the Changtan watershed was found to be acceptable. The study showed that the NPS modeling system could be applied to the simulation and prediction ofNPS loadings in the Changtan Reservoir watershed.

关键词： Changtan Reservoir watershed non-point source pollution modeling pre-rainfall soil moisture model calibration

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Analysis of rainfall runoff characteristics from a subtropical urban lawn catchment in South-east China

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Frontiers of Environmental Science & Engineering 2012年第4期6卷 531-539页

作者： Jinliang HUANG Zhenshun TU pengfei du Qingsheng LI Jie LIN Environmental Science Research Center Xiamen UniversityXiamen 361005China Department of Environmental Science and Engineering Tsinghua UniversityBeijing 100084China Fujian Institute of Oceanography Xiamen 361012China

Characteristics of rainfall runoff from a 3.26 hm^2 urban catchment with predominant land-use as lawn in Xiamen City, South-east China were investigated and analyzed. Water quality and quantity measurements of rainfall runoff were conducted for ten rainfall events over the period March, 2008 to April, 2009. The results indicated that chemical oxygen demand （COD） and total phosphorus （TP） were the major pollutants with event mean concentrations of 56.09 and 0.44mg.L^-1. From hydrograph and pollutograph analysis of two typical rainfall events, it was clear that the peak rainfall preceded the peak flowrate by about 15-20 min. Meanwhile, concentrations of major pollutants showed multiple peaks and these peaks usually preceded peak flowrate. There were no distinctive first-flush effects except for the rainfall events with the longest rainfall duration and largest runoff volume, which was verified by the fact that the first 30% runoff volume （FF30） carried 39.36% of the total suspended solids （TSS） load, 35.17% of the COD load, 28.13% of the TP load and 39.03% of the nitrate nitrogen load. Multivariate regression analysis further demonstrated that the total runoffvolume had a positive correlation with the FF30 of TSS and COD.

关键词： rainfall runoff first flush pollution characteristics urban lawn catchment

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Predictive modeling in sediment transportation across multiple spatial scales in the Jialing River Basin of China

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International Journal of Sediment Research 2015年第3期30卷 250-255页

作者： Xiaoying Liu Shi Qi Yuan Huang Yuehong Chen pengfei du China Institute of Water Resources and Hydropower Research State Key Lab.of Water Recycle Modelling20 Chegongzhuang Road West Beijing Forestry University

This research models soil erosion and sediment transportation in the Jialing River Basin based on the Revised Universal Soil Loss Equation(RUSLE) with Geographic Information System(G1S) *** have shown that,the improved method based on the RUSLE model was effective in calculating and predicting the annual sediment transport rate in Jialing River Basin in consideration of the hydrological conditions causing the annual variability of soil loss and the changes in the underlying surface resulting from land management *** the observed and simulated sediment loads in the period of 1989 and 1998,the simulation values showed a consistent trend with the observed values,and the relative errors were controlled at 20%or *** shows that the model can be used to identify hotspot watersheds with different degree of sediment yield and help to make corresponding land use planning and soil and water conservation strategy,and thus help to reduce soil erosion in areas surrounding the Three Gorges Project and other reservoirs in other rivers.

关键词： Sediment transportation Multiple spatial scales Jialing River Basin RUSLE

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Simulating hydrological responses to climate change using dynamic and statistical downscaling methods: a case study in the Kaidu River Basin, Xinjiang, China

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Journal of Arid Land 2018年第6期10卷 905-920页

作者： BA Wulong du pengfei LIU Tie BAO Anming LUO Min Mujtaba HASSAN QIN Chengxin State Key Laboratory of Environmental Simulation and Pollution Control School of EnvironmentTsinghua University Beijing 100084China State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Department of Space Sciences Institute of Space TechnologyIslamabad 44000Pakistan

Climate change may affect water resources by altering various processes in natural ecosystems. Dynamic and statistical downscaling methods are commonly used to assess the impacts of climate change on water resources. Objectively, both methods have their own advantages and disadvantages. In the present study, we assessed the impacts of climate change on water resources during the future periods (2020–2029 and 2040–2049) in the upper reaches of the Kaidu River Basin, Xinjiang, China, and discussed the uncertainties in the research processes by integrating dynamic and statistical downscaling methods (regional climate models (RCMs) and general circulation modes (GCMs)) and utilizing these outputs. The reference period for this study is 1990–1999. The climate change trend is represented by three bias-corrected RCMs (i.e., Hadley Centre Global Environmental Model version 3 regional climate model (HadGEM3-RA), Regional Climate Model version 4 (RegCM4), and Seoul National University Meso-scale Model version 5 (SUN-MM5)) and an ensemble of GCMs on the basis of delta change method under two future scenarios (RCP4.5 and RCP8.5). We applied the hydrological SWAT (Soil and Water Assessment Tool) model which uses the RCMs/GCMs outputs as input to analyze the impacts of climate change on the stream flow and peak flow of the upper reaches of the Kaidu River Basin. The simulation of climate factors under future scenarios indicates that both temperature and precipitation in the study area will increase in the future compared with the reference period, with the largest increase of annual mean temperature and largest percentage increase of mean annual precipitation being of 2.4°C and 38.4%, respectively. Based on the results from bias correction of climate model outputs, we conclude that the accuracy of RCM (regional climate model) simulation is much better for temperature than for precipitation. The percentage increase in precipitation simulated by the three RCMs is generally higher t

关键词： RCM GCM climate change downscaling bias correction SWAT Tianshan Mountains

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