To find the optimal operational condition when the properties of feedstock changes in the cracking furnace online,a hybrid algorithm named differential evolution group search optimization(DEGSO) is proposed,which is b...To find the optimal operational condition when the properties of feedstock changes in the cracking furnace online,a hybrid algorithm named differential evolution group search optimization(DEGSO) is proposed,which is based on the differential evolution(DE) and the group search optimization(GSO).The DEGSO combines the advantages of the two algorithms:the high computing speed of DE and the good performance of the GSO for preventing the best particle from converging to local optimum.A cooperative method is also proposed for switching between these two algorithms.If the fitness value of one algorithm keeps invariant in several generations and less than the preset threshold,it is considered to fall into the local optimization and the other algorithm is chosen.Experiments on benchmark functions show that the hybrid algorithm outperforms GSO in accuracy,global searching ability and efficiency.The optimization of ethylene and propylene yields is illustrated as a case by DEGSO.After optimization,the yield of ethylene and propylene is increased remarkably,which provides the proper operational condition of the ethylene cracking furnace.展开更多
The East China coastal plain is one of the most important Neolithic culture areas in China, where rich archaeological sites including those producing the earliest domesticated rice are observed. It is also a place whe...The East China coastal plain is one of the most important Neolithic culture areas in China, where rich archaeological sites including those producing the earliest domesticated rice are observed. It is also a place where landscape has experienced dramatic evolution during the Holocene when both sea level and climate changed, such that it is an ideal place for studying human-environment interaction. This study investigated over 2000 sites of pre-history and Shang and Zhou Dynasties, with 655 of which being Neolithic ages, by using DEM and GIS methods. The results suggest that the spatial and temporal distribution of Neolithic sites has largely been controlled by landscape evolution(particularly changes in coastal line), which ultimately governed by sea level changes. During early Holocene, Neolithic sites sparsely distributed in the intermountain basins of east Zhejiang Province, far from the influence of ocean. Over the period of 9–7 ka, the coastal plain(including the shelf) was largely submerged,only the feet of low hills to the south and southwest of the study area, and islands protruding the estuary, cradled limited number of settlements with characteristic "maritime components". At about 7 ka, sea level rise decelerated prominently, while sediments supply in the drainage remained high value, the combination of which led to land formation and propagation. Vast space during this period facilitated the growth of settlements in both size and number. In the mean time, however, the coastal plain was vulnerable to extreme environmental events such as storms and flooding owning to its geomorphic nature, which exerted great influence on the rise and fall of Neolithic culture.展开更多
基金Supported by the Major State Basic Research Development Program of China（2012CB720500）the National Natural Science Foundation of China（U1162202）,the National Natural Science Foundation of China（61174118）+2 种基金the National High Technology Research and Development Program of China（2012AA040307）Shanghai Key Technologies R＆D program（12dz1125100）the Shanghai Leading Academic Discipline Project（B504）
文摘To find the optimal operational condition when the properties of feedstock changes in the cracking furnace online,a hybrid algorithm named differential evolution group search optimization(DEGSO) is proposed,which is based on the differential evolution(DE) and the group search optimization(GSO).The DEGSO combines the advantages of the two algorithms:the high computing speed of DE and the good performance of the GSO for preventing the best particle from converging to local optimum.A cooperative method is also proposed for switching between these two algorithms.If the fitness value of one algorithm keeps invariant in several generations and less than the preset threshold,it is considered to fall into the local optimization and the other algorithm is chosen.Experiments on benchmark functions show that the hybrid algorithm outperforms GSO in accuracy,global searching ability and efficiency.The optimization of ethylene and propylene yields is illustrated as a case by DEGSO.After optimization,the yield of ethylene and propylene is increased remarkably,which provides the proper operational condition of the ethylene cracking furnace.
基金supported by the National Basic Research Program of China (Grant No. 2015CB953803)the National Natural Science Foundation of China (Grant No. 41672344)the CAS Strategic Priority Research Program (Grant No. XDB03020301)
文摘The East China coastal plain is one of the most important Neolithic culture areas in China, where rich archaeological sites including those producing the earliest domesticated rice are observed. It is also a place where landscape has experienced dramatic evolution during the Holocene when both sea level and climate changed, such that it is an ideal place for studying human-environment interaction. This study investigated over 2000 sites of pre-history and Shang and Zhou Dynasties, with 655 of which being Neolithic ages, by using DEM and GIS methods. The results suggest that the spatial and temporal distribution of Neolithic sites has largely been controlled by landscape evolution(particularly changes in coastal line), which ultimately governed by sea level changes. During early Holocene, Neolithic sites sparsely distributed in the intermountain basins of east Zhejiang Province, far from the influence of ocean. Over the period of 9–7 ka, the coastal plain(including the shelf) was largely submerged,only the feet of low hills to the south and southwest of the study area, and islands protruding the estuary, cradled limited number of settlements with characteristic "maritime components". At about 7 ka, sea level rise decelerated prominently, while sediments supply in the drainage remained high value, the combination of which led to land formation and propagation. Vast space during this period facilitated the growth of settlements in both size and number. In the mean time, however, the coastal plain was vulnerable to extreme environmental events such as storms and flooding owning to its geomorphic nature, which exerted great influence on the rise and fall of Neolithic culture.
