Complex survey designs often involve unequal selection probabilities of clus-ters or units within clusters. When estimating models for complex survey data, scaled weights are incorporated into the likelihood, producin...Complex survey designs often involve unequal selection probabilities of clus-ters or units within clusters. When estimating models for complex survey data, scaled weights are incorporated into the likelihood, producing a pseudo likeli-hood. In a 3-level weighted analysis for a binary outcome, we implemented two methods for scaling the sampling weights in the National Health Survey of Pa-kistan (NHSP). For NHSP with health care utilization as a binary outcome we found age, gender, household (HH) goods, urban/rural status, community de-velopment index, province and marital status as significant predictors of health care utilization (p-value < 0.05). The variance of the random intercepts using scaling method 1 is estimated as 0.0961 (standard error 0.0339) for PSU level, and 0.2726 (standard error 0.0995) for household level respectively. Both esti-mates are significantly different from zero (p-value < 0.05) and indicate consid-erable heterogeneity in health care utilization with respect to households and PSUs. The results of the NHSP data analysis showed that all three analyses, weighted (two scaling methods) and un-weighted, converged to almost identical results with few exceptions. This may have occurred because of the large num-ber of 3rd and 2nd level clusters and relatively small ICC. We performed a sim-ulation study to assess the effect of varying prevalence and intra-class correla-tion coefficients (ICCs) on bias of fixed effect parameters and variance components of a multilevel pseudo maximum likelihood (weighted) analysis. The simulation results showed that the performance of the scaled weighted estimators is satisfactory for both scaling methods. Incorporating simulation into the analysis of complex multilevel surveys allows the integrity of the results to be tested and is recommended as good practice.展开更多
Studying the topology of infrastructure communication networks(e.g., the Internet) has become a means to understand and develop complex systems. Therefore, investigating the evolution of Internet network topology migh...Studying the topology of infrastructure communication networks(e.g., the Internet) has become a means to understand and develop complex systems. Therefore, investigating the evolution of Internet network topology might elucidate disciplines governing the dynamic process of complex systems. It may also contribute to a more intelligent communication network framework based on its autonomous behavior. In this paper, the Internet Autonomous Systems(ASes) topology from 1998 to 2013 was studied by deconstructing and analysing topological entities on three different scales(i.e., nodes,edges and 3 network components: single-edge component M1, binary component M2 and triangle component M3). The results indicate that: a) 95% of the Internet edges are internal edges(as opposed to external and boundary edges); b) the Internet network consists mainly of internal components, particularly M2 internal components; c) in most cases, a node initially connects with multiple nodes to form an M2 component to take part in the network; d) the Internet network evolves to lower entropy. Furthermore, we find that, as a complex system, the evolution of the Internet exhibits a behavioral series,which is similar to the biological phenomena concerned with the study on metabolism and replication. To the best of our knowledge, this is the first study of the evolution of the Internet network through analysis of dynamic features of its nodes,edges and components, and therefore our study represents an innovative approach to the subject.展开更多
Multi-disciplinary virtual prototypes of complex products are increasingly and widely used in modern advanced manufactur- ing. How to effectively address the problems of unified modeling, composition and reuse based o...Multi-disciplinary virtual prototypes of complex products are increasingly and widely used in modern advanced manufactur- ing. How to effectively address the problems of unified modeling, composition and reuse based on the multi-disciplinary heteroge- neous models has brought great challenges to the modeling and simulation （M＆S） science and technology. This paper presents a top-level modeling theory based on the meta modeling framework （M2F） of the COllaborative SIMulation （COSlM） theory of virtual prototyping to solve the problems. Firstly the fundamental prin- ciples of the top-level modeling theory are decribed to expound the premise, assumptions, basic conventions and special require- ments in the description of complex heterogeneous systems. Next the formalized definitions for each factor in top level modeling are proposed and the hierarchical nature of them is illustrated. After demonstrating that they are self-closing, this paper divides the top- level modeling into two views, static structural graph and dynamic behavioral graph. Finally, a case study is discussed to demon- strate the feasibility of the theory.展开更多
Postulated extreme sea-level rise of up to 1-1.5 km with the late Cryogenian Ghaub deglaciation in Namibia is contentious,as is the great rapidity(<104 yr)of the sea-level rise.Such extreme glacioeustatic events,if...Postulated extreme sea-level rise of up to 1-1.5 km with the late Cryogenian Ghaub deglaciation in Namibia is contentious,as is the great rapidity(<104 yr)of the sea-level rise.Such extreme glacioeustatic events,if real,would have been global and affected all continents.In South Australia,up to six glacial advances and retreats during the late Cryogenian Elatina glaciation indicate a fluctuating ice margin.The latter stage of the Elatina glaciation and the immediate post-glacial environment are examined here for evidence of extreme and rapid sea-level rise.In the central Adelaide Rift Complex,diamictite with faceted and striated clasts occurs at the top of the Elatina Formation<1-2 m beneath the early Ediacaran Nuccaleena Formation’cap carbonate’.One hundred kilometres to the south,~30 m of siltstone and sandstone followed by^6 m of clast-poor diamictite with clasts 10+cm long occur between tidal rhythmites and the cap carbonate.Three hundred kilo metres further south,~70 m of siltsto ne,dolo mitic siltstone and minor dolomite separate tidal rhythmites and early Ediacaran strata.Hence the rhythmites were deposited during a high stand(interstadial or interglacial),not during post-glacial sea-level rise.Storm-generated erosional surfaces within tidal rhythmites at Warren Gorge indicate intermittent rhythmite deposition,and water depth and other palaeoenvironmental factors are uncertain,casting doubt on a published estimate of rapid sea-level rise during rhythmite deposition.The lack of late Cryogenian deeply incised valleys and thick valley-fill deposits in South Australia and central Australia argues against extreme sea-level variations.A hiatus occurred between Elatina deglaciation and deposition of the Nuccaleena cap carbonate,and three palaeomagnetic polarity chrons identified in the cap carbonate imply slow deposition spanning 10^5-10^6 yr.This is supported by independent evidence from magnetic chronostratigraphy for Ediacaran strata in South Australia and California,and by stratigraphic and sedimentological arguments for condensed deposition of cap carbonates.It is concluded that neither extreme nor rapid sea-level rise was associated with late Cryogenian deglaciation in South Australia.展开更多
A ligand, N^1, N^4-di （ pyridin-2-yl ） succi- namide （L） and its lanthanide（ IH ） complexes （RE = La, Eu, Tb, Gd, Yb ） were synthesized and characterized in detail. The results indicate that the composition of...A ligand, N^1, N^4-di （ pyridin-2-yl ） succi- namide （L） and its lanthanide（ IH ） complexes （RE = La, Eu, Tb, Gd, Yb ） were synthesized and characterized in detail. The results indicate that the composition of the binary complexes is determined as [ REL （H2O）2（NO3）2] NO3, that the complexes are 1 ： 1 electrolytes in DMF, and that the Tb^3＋ complex has brightly green fluorescence in a solid state. At the same time, the energy levels of the excited triplet states for the six ligands were determined to be 22989 -1 cm . The fact that the ligand sensitize Tb^3＋ complexes was explained by the relative energy gap between the lowest triplet energy level of the ligand （T） and ^5Dj of Tb^3＋ or Eu^3＋ . When 2000 cm^-1 〈 △E（T-^5D4） 〈 3000 cm^-1, the luminescent intensity of the Tb^3＋ complex is stronger. When 3000 cm^-1〈 △E （T-^5D1）, the luminescent intensity of the Eu^3＋ complex is weak- er or close to nil. This means that the triplet energy level of the ligand is a chief factor that dominates RE^3＋ luminescence.展开更多
文摘Complex survey designs often involve unequal selection probabilities of clus-ters or units within clusters. When estimating models for complex survey data, scaled weights are incorporated into the likelihood, producing a pseudo likeli-hood. In a 3-level weighted analysis for a binary outcome, we implemented two methods for scaling the sampling weights in the National Health Survey of Pa-kistan (NHSP). For NHSP with health care utilization as a binary outcome we found age, gender, household (HH) goods, urban/rural status, community de-velopment index, province and marital status as significant predictors of health care utilization (p-value < 0.05). The variance of the random intercepts using scaling method 1 is estimated as 0.0961 (standard error 0.0339) for PSU level, and 0.2726 (standard error 0.0995) for household level respectively. Both esti-mates are significantly different from zero (p-value < 0.05) and indicate consid-erable heterogeneity in health care utilization with respect to households and PSUs. The results of the NHSP data analysis showed that all three analyses, weighted (two scaling methods) and un-weighted, converged to almost identical results with few exceptions. This may have occurred because of the large num-ber of 3rd and 2nd level clusters and relatively small ICC. We performed a sim-ulation study to assess the effect of varying prevalence and intra-class correla-tion coefficients (ICCs) on bias of fixed effect parameters and variance components of a multilevel pseudo maximum likelihood (weighted) analysis. The simulation results showed that the performance of the scaled weighted estimators is satisfactory for both scaling methods. Incorporating simulation into the analysis of complex multilevel surveys allows the integrity of the results to be tested and is recommended as good practice.
基金Project supported by the National Natural Science Foundation of China(Grant No.61671142)
文摘Studying the topology of infrastructure communication networks(e.g., the Internet) has become a means to understand and develop complex systems. Therefore, investigating the evolution of Internet network topology might elucidate disciplines governing the dynamic process of complex systems. It may also contribute to a more intelligent communication network framework based on its autonomous behavior. In this paper, the Internet Autonomous Systems(ASes) topology from 1998 to 2013 was studied by deconstructing and analysing topological entities on three different scales(i.e., nodes,edges and 3 network components: single-edge component M1, binary component M2 and triangle component M3). The results indicate that: a) 95% of the Internet edges are internal edges(as opposed to external and boundary edges); b) the Internet network consists mainly of internal components, particularly M2 internal components; c) in most cases, a node initially connects with multiple nodes to form an M2 component to take part in the network; d) the Internet network evolves to lower entropy. Furthermore, we find that, as a complex system, the evolution of the Internet exhibits a behavioral series,which is similar to the biological phenomena concerned with the study on metabolism and replication. To the best of our knowledge, this is the first study of the evolution of the Internet network through analysis of dynamic features of its nodes,edges and components, and therefore our study represents an innovative approach to the subject.
基金supported by the National High Technology Research and Development Program (863 Program) (2011AA040502).
文摘Multi-disciplinary virtual prototypes of complex products are increasingly and widely used in modern advanced manufactur- ing. How to effectively address the problems of unified modeling, composition and reuse based on the multi-disciplinary heteroge- neous models has brought great challenges to the modeling and simulation （M＆S） science and technology. This paper presents a top-level modeling theory based on the meta modeling framework （M2F） of the COllaborative SIMulation （COSlM） theory of virtual prototyping to solve the problems. Firstly the fundamental prin- ciples of the top-level modeling theory are decribed to expound the premise, assumptions, basic conventions and special require- ments in the description of complex heterogeneous systems. Next the formalized definitions for each factor in top level modeling are proposed and the hierarchical nature of them is illustrated. After demonstrating that they are self-closing, this paper divides the top- level modeling into two views, static structural graph and dynamic behavioral graph. Finally, a case study is discussed to demon- strate the feasibility of the theory.
文摘Postulated extreme sea-level rise of up to 1-1.5 km with the late Cryogenian Ghaub deglaciation in Namibia is contentious,as is the great rapidity(<104 yr)of the sea-level rise.Such extreme glacioeustatic events,if real,would have been global and affected all continents.In South Australia,up to six glacial advances and retreats during the late Cryogenian Elatina glaciation indicate a fluctuating ice margin.The latter stage of the Elatina glaciation and the immediate post-glacial environment are examined here for evidence of extreme and rapid sea-level rise.In the central Adelaide Rift Complex,diamictite with faceted and striated clasts occurs at the top of the Elatina Formation<1-2 m beneath the early Ediacaran Nuccaleena Formation’cap carbonate’.One hundred kilometres to the south,~30 m of siltstone and sandstone followed by^6 m of clast-poor diamictite with clasts 10+cm long occur between tidal rhythmites and the cap carbonate.Three hundred kilo metres further south,~70 m of siltsto ne,dolo mitic siltstone and minor dolomite separate tidal rhythmites and early Ediacaran strata.Hence the rhythmites were deposited during a high stand(interstadial or interglacial),not during post-glacial sea-level rise.Storm-generated erosional surfaces within tidal rhythmites at Warren Gorge indicate intermittent rhythmite deposition,and water depth and other palaeoenvironmental factors are uncertain,casting doubt on a published estimate of rapid sea-level rise during rhythmite deposition.The lack of late Cryogenian deeply incised valleys and thick valley-fill deposits in South Australia and central Australia argues against extreme sea-level variations.A hiatus occurred between Elatina deglaciation and deposition of the Nuccaleena cap carbonate,and three palaeomagnetic polarity chrons identified in the cap carbonate imply slow deposition spanning 10^5-10^6 yr.This is supported by independent evidence from magnetic chronostratigraphy for Ediacaran strata in South Australia and California,and by stratigraphic and sedimentological arguments for condensed deposition of cap carbonates.It is concluded that neither extreme nor rapid sea-level rise was associated with late Cryogenian deglaciation in South Australia.
文摘A ligand, N^1, N^4-di （ pyridin-2-yl ） succi- namide （L） and its lanthanide（ IH ） complexes （RE = La, Eu, Tb, Gd, Yb ） were synthesized and characterized in detail. The results indicate that the composition of the binary complexes is determined as [ REL （H2O）2（NO3）2] NO3, that the complexes are 1 ： 1 electrolytes in DMF, and that the Tb^3＋ complex has brightly green fluorescence in a solid state. At the same time, the energy levels of the excited triplet states for the six ligands were determined to be 22989 -1 cm . The fact that the ligand sensitize Tb^3＋ complexes was explained by the relative energy gap between the lowest triplet energy level of the ligand （T） and ^5Dj of Tb^3＋ or Eu^3＋ . When 2000 cm^-1 〈 △E（T-^5D4） 〈 3000 cm^-1, the luminescent intensity of the Tb^3＋ complex is stronger. When 3000 cm^-1〈 △E （T-^5D1）, the luminescent intensity of the Eu^3＋ complex is weak- er or close to nil. This means that the triplet energy level of the ligand is a chief factor that dominates RE^3＋ luminescence.
文摘蛋白质复合物的检测有助于从分子水平上理解生命的活动过程。针对群智能算法检测蛋白质复合物时假阳/阴性率高、准确率低、种群多样性下降等问题,提出了基于强化学习的离散层级萤火虫算法检测蛋白质复合物(reinforcement learning-based discrete level firefly algorithm for detecting protein complexes,RLDLFA-DPC)。引入强化学习思想提出一种自适应层级划分策略,动态调整层级结构,能有效解决迭代后期种群多样性下降的问题。在层级学习策略中个体向两个优秀层级学习,避免算法陷入局部最优。为了提高蛋白质复合物检测的精度,结合个体环境信息提出自适应搜索半径的局部搜索策略。最后,在酵母蛋白质的4个数据集上,与8种经典的蛋白质复合物检测方法进行对比,验证了该方法的有效性。
