Lei Wang

Tongji University, Shanghai, Shanghai Shi, China

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Publications (137)232.24 Total impact

  • Yantai Huang · Hongjun Tian · Lei Wang
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    ABSTRACT: The optimization of energy consumption, with consequent cost reduction, is one of the main challenges for the present and future smart grid. Demand response (DR) program is expected to be vital in home energy management system (HEMS) which aims to schedule the operation of appliances to save energy costs by considering customer convenience as well as characteristics of electric appliances. The DR program is a challenging optimization problem especially when the formulations are non-convex or NP-hard problems. In order to solve this challenging optimization problem efficiently, an effective heuristic approach is proposed to achieve a near optimal solution with low computational costs. Different from previously proposed methods in literatures which are not suitable to be run in embedded devices such as a smart meter. The proposed algorithm can be implemented in an embedded device which has severe limitations on memory size and computational power, and can get an optimal value in real-time. Numerical studies were carried out with the data simulating practical scenarios are provided to demonstrate the effectiveness of the proposed method.
    International Journal of Electrical Power & Energy Systems 12/2015; 73. DOI:10.1016/j.ijepes.2015.05.032 · 3.43 Impact Factor
  • Yiu Fai Tsang · Lei Wang · Hong Chua
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    ABSTRACT: A coal slag-packed biotrickling filter inoculated with autotrophic sulphide oxidizing and ammonia oxidizing bacteria was successfully operated for co-treating hydrogen sulphide (H2S) and ammonia (NH3). Excellent removal efficiencies of H2S (98.5%) and NH3 (99.9%) were obtained at loadings of up to 120g H2Sm-3h-1 and 80g NH3m-3h-1, respectively. The inhibitory effects of selected pollutants and metabolic products on the treatment performance were evaluated through mass balance and bacterial community analyses. The presence of NH3 significantly affected the composition of metabolic products of sulphide oxidation. Elemental sulphur was the dominant metabolite that ranged from 35% to 65%, whereas the amount of sulphite and thiosulphate generally increased up to 20%. However, a similar trend in the distribution of by-products to the results of nitrogen mass balance from sole NH3 removal was observed. The predominant bacteria were also changed with different loading ratios (H2S:NH3).
  • Qiang Sheng · Lei Wang · Jihua Wu
  • He Chen · Jinfeng Niu · Tao Qin · Qi Ma · Lei Wang · Guowei Shu
    Acta Scientiarum Polonorum, Technologia Alimentaria 09/2015; 14(3):227-232. DOI:10.17306/J.AFS.2015.3.24
  • Yiu Fai Tsang · Lei Wang · Hong Chua
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    ABSTRACT: A biotrickling filter packed with coal slag as packing medium was continuously used for more than 9 months under high ammonia loading rates of up to 140 g/m3/h. Nitrogen mass balance and microbial community analysis were conducted to evaluate the inhibitory effects of high ammonia concentration and metabolic by-products on the rates of nitrification. Ammonia removal efficiency reached above 99% at an empty bed retention time of as low as 8 s wheninlet concentrations were below 350 ppm. The maximum and critical elimination capacitiesof the biotrickling filter were 118 g/m3/h and 108.1 g/m3/h, respectively. Kinetics analysisresults showed that less than 2.5 s was required for the biotrickling filter with pH controlto treat ammonia at concentrations of up to 500 ppm in compliance with the Taiwan EPAstandard (outlet NH3< 1 ppm). Results of mass balance and microbial community analysis indicated that complete removal was mainly contributed by the activities of autotrophic ammonia oxidizing bacteria and not by physical absorption or adsorption at low loading rates. However, at high inlet loadings, ammonium became the dominant by-product due to inhibitory effects of high ammonia concentration on the bacterial community.
    Process Safety and Environmental Protection 09/2015; 98:253-260. DOI:10.1016/j.psep.2015.08.008 · 2.55 Impact Factor
  • Yiu Fai Tsang · Lei Wang · Hong Chua
    Chemical Engineering Journal 08/2015; 281:389-396. · 4.32 Impact Factor
  • Wuzhao Li · Lei Wang · Xingjuan Cai · Junjie Hu · Weian Guo
    Neural Computing and Applications 06/2015; DOI:10.1007/s00521-015-1971-3 · 1.57 Impact Factor
  • Source
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    ABSTRACT: Undisturbed natural wetlands are important carbon sinks due to their low soil respiration. When compared with inland alpine wetlands, estuarine wetlands in densely populated areas are subjected to great pressure associated with environmental pollution. However, the effects of water pollution and eutrophication on soil respiration of estuarine and their mechanism have still not been thoroughly investigated. In this study, two representative zones of a tidal wetland located in the upstream and downstream were investigated to determine the effects of water organic pollution and eutrophication on soil respiration of estuarine wetlands and its mechanism. The results showed that eutrophication, which is a result of there being an excess of nutrients including nitrogen and phosphorus, and organic pollutants in the water near Shang shoal located upstream were higher than in downstream Xia shoal. Due to the absorption and interception function of shoals, there to be more nitrogen, phosphorus and organic matter in Shang shoal soil than in Xia shoal. Abundant nitrogen, phosphorus and organic carbon input to soil of Shang shoal promoted reproduction and growth of some highly heterotrophic metabolic microorganisms such as β-Proteobacteria, γ-Proteobacteria and Acidobacteria which is not conducive to carbon sequestration. These results imply that the performance of pollutant interception and purification function of estuarine wetlands may weaken their carbon sequestration function to some extent.
    PLoS ONE 05/2015; 10(5):e0126951. DOI:10.1371/journal.pone.0126951 · 3.23 Impact Factor
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    ABSTRACT: Five autotrophic strains isolated from non-photosynthetic microbial communities (NPMCs), which were screened from oceans with high CO2 fixing capability, were identified as Ochrobactrum sp. WH-2, Stenotrophomonas sp. WH-11, Ochrobactrum sp. WH-13, Castellaniella sp. WH-14, and Sinomicrobium oceani WH-15. The CO2 fixation pathways of all these strains were Calvin-Benson-Bassham pathway. These strains could metabolize multifarious organic compounds, which allowed switching them to autotrophic culture after enrichment in heterotrophic culture. The central composite response surface method indicated that these strains possessed many interactive effects, which increased the CO2 fixing efficiency of a combined community composed of these strains by 56 %, when compared with that of the single strain. Furthermore, another combined community composed of these autotrophic strains and NPMC had richer interactive relationships, with CO2 fixing efficiency being 894 % higher than that of the single strain and 148 % higher than the theoretical sum of the CO2 fixing efficiency of each of its microbial components. The interaction between strictly heterotrophic bacteria in NPMC and isolated autotrophic strains played a crucial role in improving the CO2 fixing efficiency, which not only eliminated self-restraint of organic compounds generated during the growth of autotrophic bacteria but also promoted its autotrophic pathway.
    Applied biochemistry and biotechnology 05/2015; 176(5). DOI:10.1007/s12010-015-1657-4 · 1.74 Impact Factor
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    ABSTRACT: The seawater samples collected from many different areas with different depth in the South China Sea were cultivated using different electron donors respectively. And the variation in the potential carbon fixation capability ( PCFC ) of non-photosynthetic microbial community (NPMC) in seawater with different depth was determined after a cycle of cultivation through the statistic analysis. In addition, the cause for the variation was clarified through analyzing key gene abundance regarding CO2 fixation and characteristics of seawater with different depth. The result showed that the PCFCs of NPMC in seawater with different depth were generally low and had no significant difference when using NaNO2 as the electron donor. The PCFC of NPMC in surface seawater was higher than that in deep seawater when using H2 as the electron donor, on the contrary, the PCFC of NPMC in deep seawater was higher than that in surface seawater when using Na2S2O3 as the electron donor. The abundance of the main CO2 fixation gene cbbL in surface seawater was higher than that in deep seawater while the cbbM gene abundance in deep seawater was higher than that in surface seawater. Most hydrogen-oxidizing bacteria had the cbbL gene, and most sulfur bacteria had the cbbM gene. The tendency of seawater cbbL/cbbM gene abundance with the change of depth revealed that there were different kinds of bacteria accounting for the majority in NPMC fixing CO2 at different depth of ocean, which led to different response of PCFC of NPMC at different depth of the sea to different electron donors. The distributions of dissolved oxygen and inorganic carbon concentration with the change of the depth of the sea might be an important reason leading to the difference of NPMC structure and even the difference of PCFC at different depth of the sea.
    Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 05/2015; 36(5):1550-6. DOI:10.13227/j.hjkx.2015.05.006
  • Tao Qin · Lei Wang · Zhaoli Liu · Xiaohong Guan
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    ABSTRACT: Application identification plays an essential role in network management such as intrusion detection and security monitoring. But the continuous growth of bandwidth and massive amount of packets pose serious challenges for efficacious and accurate application identification. In this paper, we develop a new method to reduce the number of packets being processed while achieving the goal of accurate P2P and VoIP application identification. Firstly, we employ the Bi-flow model to aggregate traffic packets into Bi-flow, which can capture the exchange behavior characteristics between different terminals. Then we employ the signature of Packet Size Distribution (PSD) to capture flow dynamics, which is defined as the payload length distribution probability of the packets in one Bi-flow. Secondly, we collect PSD of several different P2P and VoIP applications and the analysis results show that PSD of different applications are different with each other, which can be used as features to perform traffic identification. We also find the PSD characteristics of one Bi-flow can be captured by its first few packets, which demonstrate our methods can identify the Bi-flow quickly after its establishment. We employ the Renyi cross entropy to perform identification by calculating the similarity between PSD of the Bi-flow being identified and that of specific application. If the similarity is higher than a selected threshold, the Bi-flow being identified is classified to the specific application. Finally, as the PSD is a type of probability feature which is not sensitive to packet lose, we integrate the Poisson sampling method into our framework to process the massive data in backbone networks. Experimental results using the artificial and actual traces collected from monitoring platform in the Northwest Center of CERNET (China Education and Research Network) verify the accuracy and robustness of our method.
    Knowledge-Based Systems 03/2015; 82. DOI:10.1016/j.knosys.2015.03.002 · 2.95 Impact Factor
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    ABSTRACT: The Vicat softening temperature, melt and crystallization behavior, as well as the mechanical properties of polylactic acid (PLA)/nucleating agent (TMC-328) composites with different TMC contents were investigated. PLA/TMC composites had a modulus–temperature curve characteristic of polymers in three phases, and these phases shifted with increasing TMC concentration. Non-isothermal differential scanning calorimetry was applied to investigate the heat resistance mechanism of PLA. The heat resistant temperature was positively correlated with the degree of crystallinity, crystallization rate constant, and cold crystallization rate constant. Moreover, the arrangement and movement of molecular chains influenced the heat resistance of PLA, with an increased rigid amorphous fraction improving the heat resistance between the glass transition and cold crystallization temperatures. In conclusion, addition of the nucleating agent enhanced the crystallizability of PLA, thereby improving the heat resistance of PLA. With 0.2% (wt/wt) TMC, the Vicat softening temperature reached 134 °C, about 2.1 times that of the neat PLA (64.7 °C). An increase in the dose of nucleating agent had little impact on the tensile strength of PLA/TMC composites, but the tensile elastic modulus was increased with a higher dose of nucleating agent, after an initial decrease.KeywordsPolylactic acidNucleating agentHeterogeneous nucleationCrystallizationHeat resistance
    Materials and Design 02/2015; 66. DOI:10.1016/j.matdes.2014.10.011 · 3.50 Impact Factor
  • Xingjuan Cai · Wuzhao Li · Qi Kang · Lei Wang · Qidi Wu
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    ABSTRACT: RNA secondary structure is one important problem in bioinformatics. In this paper, one discrete binary adaptive bat algorithm is designed to solve it. In the standard version, pulse rate is exponential increased significantly, and then, pulse rate keeps a constant in most generations, this may result a fix selection pressure. To provide a large selection pressure, a linearly dynamic pulse rate selection strategy is designed. Furthermore, due to the special requirements of RNA secondary structure problem, Sigmoid function is also employed to determine the binary-value of each feature. Ten sequences from the comparative RNA website were selected for the evaluation of the proposed method. Simulation results show adaptive bat algorithm is better than Mfold.
    Journal of Computational and Theoretical Nanoscience 02/2015; 12(2). DOI:10.1166/jctn.2015.4144 · 1.34 Impact Factor
  • Xingjuan Cai · Lei Wang · Qi Kang · Qidi Wu
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    ABSTRACT: Bat algorithm is a novel swarm intelligent algorithm inspired by the echolocation behaviour of bats. Pulse rate of emission is one important parameter, which is adjusted in an exponential manner in the standard version, however, this manner provides a fast convergent behaviour in the first several generations. With this manner, the exploitation capability is limited. In this paper, a new linear adjusted manner is employed to enhance the local search capability. To test the performance, it is applied to solve the optimal coverage problem of Wireless Sensor Network (WSN). Simulation results show it is effective when compared with the standard version of bat algorithm.
    International Journal of Wireless and Mobile Computing 01/2015; 8(3):271. DOI:10.1504/IJWMC.2015.069411
  • Tao Qin · Lei Wang · Dan Zhao · Min Zhu
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    ABSTRACT: Peer-to-Peer system has achieved great success with millions of end users in the past several years. P2P traffic has occupied about 60-80 % of the total traffic volumes, which greatly consumes network bandwidth and causes congestions. To achieve the goal of efficacious P2P system management in the monitored network, in this paper we develop a framework named CUFTI (Core Users Finding and Traffic Identification). The core users are referred as long-lived peers, and we focus on life-time characteristics of coexisting peers within each snapshot of the overlay. Based on the analysis results of user’s behaviour in PPlive system, we develop an accurate model to forecast the peer’s residual life-time and identify the long-lived peers. Furthermore, we develop a flow identification model for P2P traffic management of those core users. Based on the analysis results of actual traffic traces, we find the P2P traffic flows are composed of data and control packets. Most of the control packets appear at the beginning and end of each flow to establish and close the communication between peers. We employ the direction and payload length of the control packets at the beginning of the flow as features to perform flow identification. Experimental results based on traces collected from the Northwest Region Center of CERNET (China Education and Research Network) show that the newly developed methods outperforms other existing methods with lower false negative rate (FNR) and false positive rate (FPR).
    Peer-to-Peer Networking and Applications 01/2015; DOI:10.1007/s12083-015-0350-2 · 0.63 Impact Factor
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    ABSTRACT: Many efforts have been made to control invasive Spartinaalterniflora and to restore coastal wetlands along the Pacific Rim. This study is the first to report the effects of a Spartina-eradication program on soil greenhouse gas (GHG) emissions. In this study S. alterniflora was eradicated in a pilot program covering an area of 0.63 km2 in a Yangtze River estuarine wetland. In the following year after the eradication program was complete, plant growth, soil microbial activities, as well as CO2, CH4 and N2O emissions were investigated. S. alterniflora ramets did not re-grow after the eradication program, while a native plant, Phragmites australis, thrived and produced taller but rather thinner ramets. CO2, CH4 and N2O emissions in areas previously covered by S. alterniflora declined based on measurements made a year after eradication. This may have been caused by the removal of this plant as well as by flooding and/or by the reduced soil microbial biomass and dehydrogenase and β-glucosidase activities. CH4 fluxes significantly increased in the program sites where the native species P. australis was retained, while CO2 and N2O fluxes showed no significant changes. Our study revealed that GHG emissions can be greatly altered by an invasive plant eradication program and analysis of such emissions should be included in comprehensive assessments designed to guide successful restoration practices. Based on scenario analysis, we suggest that from the view of GHG emission equivalency, planting P. australis in approximately 50% of the area where S. alterniflora was eradicated would be appropriate in future management.
    Ecological Engineering 12/2014; 73:229–237. DOI:10.1016/j.ecoleng.2014.09.031 · 2.58 Impact Factor
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    ABSTRACT: Estuarine wetland, where freshwater mixes with salt water, comprises different regions (rivers and marine ecosystems) with significantly varying tidal salinities. Two sampling areas, ZXS and JS, were selected to investigate the effect of tidal salinity on soil respiration (SR). ZXS and JS were located in Zhongxia Shoal and Jiangyanan Shoal of Jiuduansha Wetland respectively, with similar elevation and plant species, but significantly different in salinity. The results showed that with almost identical plant biomass, the SR and soil microbial respiration (SMR) of the tidal wetland with lower salinity (JS) were significantly higher than those of the tidal wetland with higher salinity (ZXS) (p<0.05). However, unlike SMR and SR, the difference in the soil microbial biomass (SMB) was not significant (p>0.05) with the SMB of ZXS a little higher than that of JS. The higher SMR and SR of JS may be closely connected to the soil microbial community structures and amount of dominant bacteria. Abundant β- and γ-Proteobacteria and Actinobacteria in JS soil, which have strong heterotrophic metabolic capabilities, could be the main reason for higher SMR and SR, whereas a high number of ε-Proteobacteria in ZXS, some of which have carbon fixation ability, could be responsible for relatively lower carbon output. Path analysis indicated that soil salinity had the maximum negative total influencing coefficient with SMR among the various soil physical and chemical factors, suggesting that higher soil salinity, restricting highly heterotrophic bacteria, is the principle reason for lower SMR and SR in the ZXS. Copyright © 2014. Published by Elsevier B.V.
    Journal of Environmental Sciences 12/2014; 26(12):2562-2570. DOI:10.1016/j.jes.2014.07.016 · 2.00 Impact Factor
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    ABSTRACT: Abstract As non-photosynthetic microbial community (NPMC) isolated from seawaters utilized inorganic carbon sources for carbon fixation, the concentrations and ratios of Na2CO3, NaHCO3, and CO2 were optimized by response surface methodology design. With H2 as the electron donor, the optimal carbon sources were 270 mg/L Na2CO3, 580 mg/L NaHCO3, and 120 mg/L CO2. The carbon fixation efficiency as respond to total organic carbon (TOC) was up to 30.59 mg/L with optimal carbon sources, which was about 50% higher than that obtained with CO2 as the sole carbon source. The mixture of inorganic carbon sources developed a buffer system to prevent acidification or alkalization of the medium caused by CO2 or Na2CO3, respectively. Furthermore, CO2 and HCO3(-), the starting points of carbon fixation in the pathways of Calvin-Benson-Bassham and 3-hydroxypropionate cycles, were provided by the carbon source structure to facilitate carbon fixation by NPMC. However, in the presence of mixed electron donors composed of 1.25% Na2S, 0.50% Na2S2O3, and 0.457% NaNO2, the carbon source structure did not exhibit significant improvement in the carbon fixation efficiency, when compared that achieved with CO2 as the sole carbon source. The positive effect of mixed electron donors on inorganic carbon fixation was much higher than that of the carbon source structure. Nevertheless, the carbon source structure could be used as an alternative to CO2 when using NPMC to fix carbon in industrial processes.
    Environmental Technology 11/2014; 36(10):1-32. DOI:10.1080/09593330.2014.983991 · 1.56 Impact Factor
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    ABSTRACT: A combined process comprised of ex-situ nitrification in an aged refuse bioreactor (designated as A bioreactor) and in-situ denitrification in a fresh refuse bioreactor (designated as F bioreactor) was constructed for investigating N2O emission during the stabilization of municipal solid waste (MSW). The results showed that N2O concentration in the F bioreactor varied from undetectable to about 130 ppm, while it was much higher in the A bioreactor with the concentration varying from undetectable to about 900 ppm. The greatly differences of continuous monitoring of N2O emission after leachate cross recirculation in each period were primarily attributed to the stabilization degree of MSW. Moreover, the variation of N2O concentration was closely related to the leachate quality in both bioreactors and it was mainly affected by the COD and COD/TN ratio of leachate from the F bioreactor, as well as the DO, ORP, and NO3−-N of leachate from the A bioreactor.
    Waste Management 11/2014; 34(11). DOI:10.1016/j.wasman.2014.06.023 · 3.22 Impact Factor
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    ABSTRACT: Abstract The Co–Fe/Mg/Al catalysts were prepared from the hydrotalcite-like compounds containing Co, Fe, Mg and Al, and applied to the steam gasification of biomass-derived tar. The characterization using TPR, TPO, XRD, H2 adsorption, TEM and EXAFS indicates that the Co–Fe/Mg/Al catalysts have a nanocomposite structure of the Co–Fe bcc alloy particles and the oxide particles of MgAl2O4-based solid solution after the reduction, where Co metal atoms can substitute partially Fe metal sites in bcc Fe metal regarding the Co–Fe bcc alloy particles. The composition of the Co–Fe/Mg/Al catalysts was optimized on the basis of the activity tests. The optimized Co–Fe/Mg/Al catalyst exhibited higher catalytic performance than the reported catalysts such as Co–Fe/α-Al2O3, Co/Mg/Al, Ni–Fe/Mg/Al in terms of activity and resistance to coke deposition. This behavior can be explained by the formation of the Co–Fe bcc alloy nanoparticles with rather uniform composition on MgAl2O4-based solid solution.
    Applied Catalysis B Environmental 11/2014; 160–161(1):701 - 715. DOI:10.1016/j.apcatb.2014.06.021 · 7.44 Impact Factor

Publication Stats

635 Citations
232.24 Total Impact Points


  • 2002–2015
    • Tongji University
      • • Key Laboratory of Water Environment of Yangtze River
      • • College of Environmental Science and Engineering
      • • Department of Control Science and Engineering
      • • Department of Environmental Engineering
      Shanghai, Shanghai Shi, China
  • 2013–2014
    • Beijing Technology and Business University
      Peping, Beijing, China
  • 2011–2014
    • Tohoku University
      • Department of Applied Chemistry
  • 2010
    • Yunnan Agricultural University
      Panlong, Shaanxi, China