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Users'experience matter:Delay sensitivity-aware computation offloading in mobile edge computing

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Digital Communications and Networks 2022年第6期8卷 955-963页

作者： Mingzhi Wang Tao Wu Tao Ma Xiaochen Fan Mingxing Ke National University of Defense technology Hefei230031China Consulting center for Strategic assessment Academy of Military ScienceBeijing100091China

As a promising computing paradigm,Mobile Edge Computing(MEC)provides communication and computing capability at the edge of the network to address the concerns of massive computation requirements,constrained battery capacity and limited bandwidth of the Internet of Things(IoT)*** existing works on mobile edge task ignores the delay sensitivities,which may lead to the degraded utility of computation offloading and dissatisfied *** this paper,we study the delay sensitivity-aware computation offloading by jointly considering both user's tolerance towards delay of task execution and the network status under computation and communication ***,we use a specific multi-user and multi-server MEC system to define the latency sensitivity of task offloading based on the analysis of delay distribution of task ***,we propose a scoring mechanism to evaluate the sensitivity-dependent utility of task execution and devise a Centralized Iterative Redirection Offloading(CIRO)algorithm to collect all information in the MEC *** starting with an initial offloading strategy,the CIRO algorithm enables IoT devices to cooperate and iteratively redirect task offloading decisions to optimize the offloading strategy until it *** simulation results show that our method can significantly improve the utility of computation offloading in MEC systems and has lower time complexity than existing algorithms.

关键词： Mobile edge computing Computation floading Delay sensitivity Centralized ofloading

Effect of phosphate releasing in activated sludge on phosphorus removal from municipal wastewater

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Journal of Environmental Sciences 2018年第5期30卷 216-223页

作者： Jie Ge Xiaoguang Meng Yonghui Song Amalia Terracciano center of Environmental Systems Stevens Institute of Technology State Key Laboratory of Environmental Criteria and Risk assessment Chinese Research Academy of Environmental Sciences

Aluminum and ferric salts are commonly used in municipal wastewater treatment plants（WWPTs） for phosphorus（P） removal. In this study, on-site jar tests were conducted to determine the removal of different P species from the fresh samples in the presence and absence of activated sludge（AS） with different doses of alum, poly-aluminum chloride,and ferric chloride at different p H. The soluble P（SP） concentration in the samples was about 0.63 mg/L. When the mixed liquor containing AS was treated with 8 mg/L of Al, SP could be reduced to 0.13 mg/L, while it was reduced to 0.16 mg/L with only 1 mg/L of Al after sedimentation removal of AS from sample. Chemical analysis determined that AS contained 59.8 mg-P/g-TSS and 43.8 mg-Al/g-TSS and most of the P was associated with the aluminum hydroxide. We discovered that the phosphate in the AS could readily be released from it, which was mainly responsible for ineffective removal of P to low levels in mixed liquor even with very high alum dose. This study provides new insight into the behavior and fate of P in the wastewater treatment plants that use alum to enhance P removal in the final effluent.

关键词： Phosphorus release Coagulation Activated sludge (AS) Wastewater treatment

Investigation on regional attenuation of Vrancea (Romania) intermediate-depth earthquakes

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Earthquake Engineering and Engineering Vibration 2018年第3期17卷 501-509页

作者： Florin Pavel Radu Vacareanu Seismic Risk assessment Research center Technical University of Civil Engineering

This paper aims at investigating possible regional attenuation patterns in the case of Vrancea（Romania） intermediate-depth *** 500 pairs of horizontal components recorded during 13 intermediate-depth Vrancea earthquakes are employed in order to evaluate the regional attenuation *** recordings are grouped according to the azimuth with regard to the Vrancea seismic source and subsequently,Q models are computed for each azimuthal zone assuming similar geometrical ***,the local soil amplification which was disregarded in a previous analysis performed for Vrancea intermediate-depth earthquakes is now clearly *** results show minor differences between the four regions situated in front of the Carpathian Mountains and considerable differences in attenuation of seismic waves between the forearc and backarc regions（with regard to the Carpathian Mountains）.Consequently,an average Q model of the type Q（f） = 115×f^1.25 is obtained for the four forearc regions,while a separate Q model of the type Q（f） = 70×f^0.90 is computed for the backarc *** results highlight the need to evaluate the seismic hazard of Romania by using ground motion models which take into account the different attenuation between the forearc/backarc regions.

关键词： Fourier amplitude spectrum azimuth dependency source-to-site distance Q model local soil conditions

Quantitative evaluation of air pollution in transport strategic environmental assessment:a case study based on uncertainty analysis and graphic information system technology

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第5期11卷 370-381页

作者： Hong-tao BAI Hui-zhi WANG He XU Tan ZHU Research center for Strategic Environmental assessment Nankai University Tianjin 300071 China

Although the impact of road transport on urban air quality has achieved a high profile in China,still greater attention is required as it has not yet been considered fully even in relation to the road network linking cities and urban areas. Strategic environmental assessment (SEA) is a systematic and comprehensive process for evaluating the environmental impacts of a policy,plan or program in publicly accountable decision-making. Air pollution has been recognized as a significant issue in most transport SEA practices. The Strategic Environmental assessment of the Hubei Road Network Plan (2002-2020) (HRNP) was introduced as one of the World Bank's pilot SEA projects. An effective framework was developed to investigate the functional relationship between the road network and its potential air pollutant emissions. In this study,two indicators were identified:emission intensity/ inventory of pollutants and the spatial distribution of the most polluted areas. Because strategic actions are inherently nebulous and data quality is often disappointing,three alternative scenarios were employed to address uncertainties and data/scale issues. Calculations were made using emission models and results were analyzed with the help of statistical tools and the geographic information system (GIS). The results from the project implementation and the feedback from the World Bank have both shown that the proposed framework is effective in the transport SEA process.

关键词： Air pollution Transport strategic environmental assessment (SEA) Quantitative evaluation Uncertainty

Gravimetric analysis for PM_(2.5) mass concentration based on year-round monitoring at an urban site in Beijing

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Journal of Environmental Sciences 2016年第2期28卷 154-160页

作者： Yanli Wang Wen Yang Bin Han Wenjie Zhang Mindong Chen Zhipeng Bai State Key Laboratory of Environmental Criteria and Risk assessment Chinese Research Academy of Environmental Sciences Collaborative Innovation center of Atmospheric Environment and Equipment technology Nanjing University of Information Science & Technology

Daily PM_（2.5）（particulate matter with an aerodynamic diameter of below 2.5 μm） mass concentrations were measured by gravimetric analysis in Chinese Research Academy of Environmental Sciences（CRAES）, in the northern part of the Beijing urban area, from December 2013 to April 2015. Two pairs of Teflon（T1/T2） and Quartz（Q1/Q2） samples were obtained, for a total number of 1352 valid filters. Results showed elevated pollution in Beijing,with an annual mean PM_（2.5）mass concentration of 102 μg/m^3. According to the calculated PM_（2.5）mass concentration, 50% of our sampling days were acceptable（PM_（2.5）〈 75 μg/m^3）, 30% had slight/medium pollution（75–150 μg/m^3）, and 7% had severe pollution（〉 250 μg/m^3）. Sampling interruption occurred frequently for the Teflon filter group（75%） in severe pollution periods,resulting in important data being missing. Further analysis showed that high PM_（2.5）combined with high relative humidity（RH） gave rise to the interruptions. The seasonal variation of PM_（2.5）was presented, with higher monthly average mass concentrations in winter（peak value in February, 422 μg/m^3）, and lower in summer（7 μg/m^3 in June）. From May to August, the typical summer period, least severe pollution events were observed, with high precipitation levels accelerating the process of wet deposition to remove PM_（2.5）. The case of February presented the most serious pollution, with monthly averaged PM_（2.5）of 181 μg/m^3 and 32% of days with severe pollution. The abundance of PM_（2.5）in winter could be related to increased coal consumption for heating needs.

关键词： PM_(2.5) Gravimetric analysis Sampling interruption Pollution level Relative humidity(RH) Seasonal variation

Study of Migration and Safety assessment of Manganese(Mn)from Food Contact Stainless-Steel Products in China

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Biomedical and Environmental Sciences 2022年第4期35卷 361-365页

作者： ZHANG Hong XING Hang LIU Zai Mei LI Qian Yun CHEN Shao Hong ZHU Lei China National center for Food Safety Risk assessment Beijing 100022China Ningbo Customs technology center Ningbo 315192ZhejiangChina

Metal alloys,especially stainless-steel,are widely used in the preparation,production and storage of food,because of their corrosion resistance and barrier *** food contact(FC)stainlesssteel articles are designed for repeated,long-term use,and the migration of heavy metals is regarded as the main safety risk when they make contact with ***(Mn)is an important alloying element in stainless-steel,and its potential to migrate has caused considerable consumer concern.

关键词： properties. steel migrate

Evaluation of the seismic hazard for 20 cities in Romania using Monte Carlo based simulations

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Earthquake Engineering and Engineering Vibration 2017年第3期16卷 513-523页

作者： Florin Pavel Radu Vacareanu Seismic Risk assessment Research center Technical University of Civil Engineering Bucharest Romania

This work focuses on the evaluation of the seismic hazard for Romania using earthquake catalogues generated by a Monte Carlo approach. The seismicity of Romania can be attributed to the Vrancea intermediate-depth seismic source and to 13 other crustal seismic sources. The recurrence times of large magnitude seismic events（both crustal and subcrustal）, as well as the moment release rates are computed using simulated earthquake catalogues. The results show that the largest contribution to the overall moment release for the crustal seismic sources is from the seismic regions in Bulgaria, while the seismic regions in Romania contribute less than 5% of the overall moment release. In addition, the computations show that the moment release rate for the Vrancea subcrustal seismic source is about ten times larger than that of all the crustal seismic sources. Finally, the Monte Carlo approach is used to evaluate the seismic hazard for 20 cities in Romania with populations larger than 100,000 inhabitants. The results show some differences between the seismic hazard values obtained through Monte-Carlo simulation and those in the Romanian seismic design code P100-1/2013, notably for cities situated in the western part of Romania that are influenced by local crustal seismic sources.

关键词： seismic sources uncertainty seismic moment GMPE percentile

Effects of Forging and Heat Treatments on the Microstructure and Oxidation Behavior of 316LN Stainless Steel in High Temperature Water

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Journal of Materials Science & technology 2015年第4期31卷 403-412页

作者： Yueling Guo En-Hou Han Jianqiu Wang National center for Materials Service Safety University of Science and Technology Beijing Key Laboratory of Nuclear Materials and Safety assessment Institute of Metal ResearchChinese Academy of Science

Microstructure of 316 LN stainless steel(ss),including the as-received material and samples processed by solution anneal treatment and stress relief treatment after forging,was characterized by Vickers hardness(HV) testing and electron back scattering diffraction(EBSD).The oxide film formed on samples after immersion in borated and lithiated water at 583.15 K was investigated by scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS).Results showed that the grain size of samples was largely reduced after *** fraction of coincidence site lattice(CSL) boundaries and lower residual strain were observed in samples with either solution anneal treatment or stress relief *** proportion of CSL boundaries was largely enhanced by solution anneal treatment after forging,due to the recrystallization occurring during solution anneal *** oxide film grown on 316 LNss with solution anneal treatment after forging exhibited more strong protectiveness,as compared to the oxide film grown on samples with stress relief treatment after forging and the oxide film grown on asreceived samples without *** mechanisms of oxidation were then discussed.

关键词： Stainless steel Forging Corrosion Residual strain

Theoretical Risk assessment of Dietary Exposure to Brilliant Blue FCF in Chinese Population

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Biomedical and Environmental Sciences 2019年第2期32卷 126-129页

作者： WANG Hua Li DING Hao CAO Pei ZHANG Jian Bo WU Di TIAN Jing China National center For Food Safety Risk assessment

Brilliant blue FCF is a dye and synthe c colorant with a triphenylmethane base structure. It is permi ed as a food addi ve in many countries and regions. In recent years, Codex Alimentarius Commission[1], the European Union[2], Australia, New Zealand[3], the United States[4], China, and other countries have allowed the use of brilliant blue FCF as a food colorant.

关键词： FCF