Aim To present a quantitative method for structural complexity analysis and evaluation of information systems. Methods Based on Petri net modeling and analysis techniques and with the aid of mathematical tools in ge...Aim To present a quantitative method for structural complexity analysis and evaluation of information systems. Methods Based on Petri net modeling and analysis techniques and with the aid of mathematical tools in general net theory(GNT), a quantitative method for structure description and analysis of information systems was introduced. Results The structural complexity index and two related factors, i.e. element complexity factor and connection complexity factor were defined, and the relations between them and the parameters of the Petri net based model of the system were derived. Application example was presented. Conclusion The proposed method provides a theoretical basis for quantitative analysis and evaluation of the structural complexity and can be applied in the general planning and design processes of the information systems.展开更多
The evolutionary trend of organisms, which often evolved from a simpler structure to a more complex structure, is a mystery. It seems that the later living things appeared on the earth, the more complex their structur...The evolutionary trend of organisms, which often evolved from a simpler structure to a more complex structure, is a mystery. It seems that the later living things appeared on the earth, the more complex their structures were. This study pointed out that the evolutionary trend of organisms was the result of the organisms' asymmetric evolution-the phenomenon which the partition of the more complex structure was actually larger than that of the simpler structure on the same evolutionary platform of organisms, it explained the cause of the asymmetric evolution and listed much important evidence for organisms' asymmetric evolution.展开更多
Based on protein-DNA complex crystal structural data in up-to-date Nucleic Acid Database,the related parameters of DNA Kinetic Structure were investigated by Monte-Carlo Multiple Integrals on the base of modified DNA ...Based on protein-DNA complex crystal structural data in up-to-date Nucleic Acid Database,the related parameters of DNA Kinetic Structure were investigated by Monte-Carlo Multiple Integrals on the base of modified DNA structure statistical mechanical model,and time complexity and precision were analyzed on the calculated results.展开更多
Global semantic structures of two large semantic networks, HowNet and WordNet, are analyzed. It is found that they are both complex networks with features of small-world and scale-free, but with special properties. Ex...Global semantic structures of two large semantic networks, HowNet and WordNet, are analyzed. It is found that they are both complex networks with features of small-world and scale-free, but with special properties. Exponents of power law degree distribution of these two networks are between 1.0 and 2. 0, different from most scale-free networks which have exponents near 3.0. Coefficients of degree correlation are lower than 0, similar to biological networks. The BA (Barabasi-Albert) model and other similar models cannot explain their dynamics. Relations between clustering coefficient and node degree obey scaling law, which suggests that there exist self-similar hierarchical structures in networks. The results suggest that structures of semantic networks are influenced by the ways we learn semantic knowledge such as aggregation and metaphor.展开更多
To provide system designer a valid measure to evaluate the structure complexityof class diagrams objectively, this letter first proposes a method to transform a class diagramsinto a weighted class dependence graph, th...To provide system designer a valid measure to evaluate the structure complexityof class diagrams objectively, this letter first proposes a method to transform a class diagramsinto a weighted class dependence graph, then presents a structure complexity measure for classdiagrams based on entropy distance.展开更多
The conventional X-ray gray weighted image fusion method based on variable energy cannot characterize the phys- ical properties of complicated objects correctly, therefore, the gray correction method of X-ray fusion i...The conventional X-ray gray weighted image fusion method based on variable energy cannot characterize the phys- ical properties of complicated objects correctly, therefore, the gray correction method of X-ray fusion image based on neural network is proposed. The conventional method acquires 12 bit images on variable energy, and then fuses the images in a tra- ditional way. While the new method takes the fusion image as the input of neural network simulation system and takes the acquired 16 bit image as the output of neural network. The X-ray image physical characteristic model based on neural net- work is obtained through training. And then it takes steel ladder block as the test object to verify the feasibility of the mod- el. In the end, the gray curve of output image is compared with the gray curve of 16 bit real image. The experiment results show that this method can fit the nonlinear relationship between the fusion image and the real image, and also can expand the scope of application of low dynamic image acquisition equipment.展开更多
Segmentation of three-dimensional(3D) complicated structures is of great importance for many real applications.In this work we combine graph cut minimization method with a variant of the level set idea for 3D segmenta...Segmentation of three-dimensional(3D) complicated structures is of great importance for many real applications.In this work we combine graph cut minimization method with a variant of the level set idea for 3D segmentation based on the Mumford-Shah model.Compared with the traditional approach for solving the Euler-Lagrange equation we do not need to solve any partial differential equations.Instead,the minimum cut on a special designed graph need to be computed.The method is tested on data with complicated structures.It is rather stable with respect to initial value and the algorithm is nearly parameter free.Experiments show that it can solve large problems much faster than traditional approaches.展开更多
Accurately solving transient nonlinear inverse heat conduction problems in complex structures is of great importance to provide key parameters for modeling coupled heat transfer process and the structure’s optimizati...Accurately solving transient nonlinear inverse heat conduction problems in complex structures is of great importance to provide key parameters for modeling coupled heat transfer process and the structure’s optimization design.The finite element method in ABAQUS is employed to solve the direct transient nonlinear heat conduction problem.Improved particle swarm optimization(PSO)method is developed and used to solve the transient nonlinear inverse problem.To investigate the inverse performances,some numerical tests are provided.Boundary conditions at inaccessible surfaces of a scramjet combustor with the regenerative cooling system are inversely identified.The results show that the new methodology can accurately and efficiently determine the boundary conditions in the scramjet combustor with the regenerative cooling system.By solving the transient nonlinear inverse problem,the improved particle swarm optimization for solving the transient nonlinear inverse heat conduction problem in a complex structure is verified.展开更多
In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large...In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large size, complex structure and poor low pressure atomization effect in comparison with requirement of snake-like fire rescue robots. On the basis of comprehensive typical spray noz- zles, a direct spiral double helix converging nozzle (DSDHCN) is proposed, which has the advanta- ges of small volume, light weight, simple structure, and convenient installation. To make the spray nozzle have good performance, and meet the requirements of more efficient fire extinguishing, a nu- merical study is carried out to analyze the internal and external full flow field of nozzle. A gas-liquid two-phase flow is applied to simulate the external full flow field of nozzle with VOF model in fluent software. The simulation results show the real situation of water flow out of the atomization nozzle and the water jet trajectory. Some simulations about middle or low water pressure direct spiral double he- lix converging optimized nozzle have been done in 30bar pressure. The simulation results show that the optimized nozzle structure not only makes the spray droplets have a good cone angle, but also have a sufficient axial velocity,which proves the structure rationality of the proposed optimized nozzle.展开更多
To explore the structural characteristics and vulnerability of multimodal transport networks,this study identifies the structural characteristics of a multimodal transport network on the basis of the complex network t...To explore the structural characteristics and vulnerability of multimodal transport networks,this study identifies the structural characteristics of a multimodal transport network on the basis of the complex network theory.Key nodes are clarified from the analysis of the structural characteristics.The characteristic path length and percentage of the largest subgraph are applied to analyze the vulnerability of the multimodal transport network after random and intentional attacks on the nodes.The network of a multimodal transport company is taken as an example in the empirical analysis.Results show that with more than ten nodes under a random attack,the percentage of the largest subgraph is less than 20%,and the characteristic path length is less than 2.The same performance is observed for more than seven nodes under an intentional attack.The multimodal transport network is more vulnerable under an international attack against key nodes.The results of the topology and node failure under random or intentional attacks would support the management of the multimodal transport network.Suggestions for the emergency transportation organization of enterprises under attacks are proposed accordingly.These suggestions should help improve network invulnerability and recovery from node failure.展开更多
Taizhou Bridge is the first kilometer level three-pylon two-span suspension bridge in the world and the structural complexity has significant effects on the seismic performance of the bridge. Shaking table test of Tai...Taizhou Bridge is the first kilometer level three-pylon two-span suspension bridge in the world and the structural complexity has significant effects on the seismic performance of the bridge. Shaking table test of Taizhou Bridge is arranged to investigate the effects of non-uniform ground motion input, collision between main and side spans and optimal seismic structural system. It's very important and difficult to design and manufacture the scaled down model of Taizhou Bridge used during the shaking table test. The key point is that the girder and pylons are very hard to be manufactured if the similarity ratio is strictly followed. Based on the finite element method (FEM) analysis, a simplified scaled down model is designed and the bending stiffness of the girder and pylon are strictly simulated, and the torsion stiffness and axial stiffness are not strictly simulated. The inner forces and displacements of critical sections, points of simplified model and theoretical model are compared by FEM analysis, and it's found out that the difference between the seismic responses is relatively small. So, the simplified model can be used to conduct the shaking table test by the FEM verification.展开更多
Aggressive behavior can be an important factor in determining how animals use and divide space and resources. Previous studies have shown that aggression in fishes can be influenced by a variety of factors, including ...Aggressive behavior can be an important factor in determining how animals use and divide space and resources. Previous studies have shown that aggression in fishes can be influenced by a variety of factors, including water temperature and resource levels. In this study, we tested if the amount of habitat structure in the environment affected aggression levels in female convict cichlids Archocentrus nigrofasciatus. We performed a laboratory experiment in which we placed female convict cichlids into an aquarium with low or high amounts of habitat structure and monitored the dominant female's behavior toward the subordinate female. Aggressive behavior in convict cichlids primarily consists of chases and bites. We found that the total time the dominant female spent chasing the subordinate female was greater when there was a low amount of habitat structure as compared to when there was a high amount of habitat structure. We also found that both the average duration of a chasing bout and the number of bites directed at the subordinate fish increased when there was a low amount of structure, but the number of chases did not. These results indicate that increased habitat structural complexity decreases aggressive behavior in convict cichlids [Current Zoology 56 (1): 52-56, 2010].展开更多
Offshore jacket platforms are widely used in offshore oil and gas exploitation.Finite element models of such structures need to have many degrees of freedom(DOFs) to represent the geometrical detail of complex structu...Offshore jacket platforms are widely used in offshore oil and gas exploitation.Finite element models of such structures need to have many degrees of freedom(DOFs) to represent the geometrical detail of complex structures,thereby leading to incompatibility in the number of DOFs of experimental models.To bring them both to the same order while ensuring that the essential eigen-properties of the refined model match those of experimental models,an extended model refinement procedure is presented in this paper.Vibration testing of an offshore jacket platform model is performed to validate the applicability of the proposed approach.A full-order finite element model of the platform is established and then tuned to meet the measured modal properties identified from the acceleration signals.Both model reduction and modal expansion methods are investigated,as well as various scenarios of sensor arrangements.Upon completion of the refinement,the updated jacket platform model matches the natural frequencies of the measured model well.展开更多
Refinery system, a typical example of process systems, is presented as complex network in this paper. The topology of this system is described by task-resource network and modeled as directed and weighted graph, in wh...Refinery system, a typical example of process systems, is presented as complex network in this paper. The topology of this system is described by task-resource network and modeled as directed and weighted graph, in which nodes represent various tasks and edges denote the resources exchanged among tasks. Using the properties of node degree distribution, strength distribution and other weighted quantities, we demonstrate the heterogeneity of the network and point out the relation between structural characters of vertices and the functionality of correspond- ing tasks. The above phenomena indicate that the design requirements and principles of production process contrib- ute to the heterogeneous features of the network. Besides, betweenness centrality of nodes can be used as an impor- tance indicator to provide additional information for decision making. The correlations between structure and weighted properties are investigated to further address the influence brought by production schemes in system con- nectivity patterns. Cascading failures model is employed to analyze the robustness of the network when targeted at- tack happens. Two capacity assignment strategies are compared in order to improve the robustness of the network at certain cost. The refinery system displays more reliable behavior when the protecting strategy considers heteroge- neous properties. This phenomenon further implies the structure-activity relationship of the refinery system and provides insightful suggestions for process system design. The results also indicate that robustness analysis is a _promising applicat!on of methodologies from complex networks to process system engineering..展开更多
Clustering data with varying densities and complicated structures is important,while many existing clustering algorithms face difficulties for this problem. The reason is that varying densities and complicated structu...Clustering data with varying densities and complicated structures is important,while many existing clustering algorithms face difficulties for this problem. The reason is that varying densities and complicated structure make single algorithms perform badly for different parts of data. More intensive parts are assumed to have more information probably,an algorithm clustering from high density part is proposed,which begins from a tiny distance to find the highest density-connected partition and form corresponding super cores,then distance is iteratively increased by a global heuristic method to cluster parts with different densities. Mean of silhouette coefficient indicates the cluster performance. Denoising function is implemented to eliminate influence of noise and outliers. Many challenging experiments indicate that the algorithm has good performance on data with widely varying densities and extremely complex structures. It decides the optimal number of clusters automatically.Background knowledge is not needed and parameters tuning is easy. It is robust against noise and outliers.展开更多
The International Civil Aviation Organization (ICAO) is a specialized agency of the United Nations. Functionally, it has emerged as the organizational necessity of both the universal complex structure and the import...The International Civil Aviation Organization (ICAO) is a specialized agency of the United Nations. Functionally, it has emerged as the organizational necessity of both the universal complex structure and the importance of its overall activity. It was created on the basis of Article 57 of the United Nations Charter, stipulating that the specialized UN agencies are autonomous international organizations. They enjoy their autonomy on the basis of the contract they were established by, being engaged in activities within the United Nations system. On the territories the organization member states comprise, they enjoy privileges and immunities, having the international legal capacity to carry out their activities in accordance to the Statute. The 1944 Multilateral Convention was to establish both protection and efficient development of international civil aviation. In accordance to that rights and obligations of member states were established. It is of a special importance to emphasize obligation of parties to take their parts in both co-operation and programs aimed at improvement of international transport, navigational equipment, and installations. In the globalized world of today, air traffic is an irreplaceable part of the system of communication. It enables fast and timely business contacts between the people from various continents, as well as transport of goods.展开更多
The nominal group is an important aspect of English and other languages and requires specific attention because of its complex structure and sequence. This study examines how sequencing affects users' understanding a...The nominal group is an important aspect of English and other languages and requires specific attention because of its complex structure and sequence. This study examines how sequencing affects users' understanding and interpretation of the English nominal group and attempts to prescribe guidelines to the different challenges which the complex ordering of the nominal group poses to users of English as a second language. The findings of the study indicate that the complex ordering of the nominal group has a significant impact on their semantic effects in any discourse, and many of the difficulties users of English as a second language are faced with have to do with lack of adequate understanding of the structure and usage of the nominal group. Some of these problems can be addressed through a comprehensive study and examination of linguists' explanation of the nominal group and practical application of their guidelines. A functional approach to the study of the group will help second language learners of English to have a better understanding of its structure展开更多
It is a fairly challenging issue to make image repositories easy to be searched and browsed. This depends on a technique--image clustering. Kernel-based clustering algorithm has been one of the most promising clusteri...It is a fairly challenging issue to make image repositories easy to be searched and browsed. This depends on a technique--image clustering. Kernel-based clustering algorithm has been one of the most promising clustering methods in the last few years, beeanse it can handle data with high dimensional complex structure. In this paper, a kernel fuzzy learning (KFL) algorithm is proposed, which takes advantages of the distance kernel trick and the gradient-based fuzzy clustering method to execute the image clustering automatically. Experimental results show that KFL is a more efficient method for image clustering in comparison with recent renorted alternative methods.展开更多
Starting from iterated systems, it is shown that the homoclinic (heteroclinic) orbit is a kind of spiral structure. The emphasis is laid to show that there are homoclinic or heteroclinic orbits in complex discrete and...Starting from iterated systems, it is shown that the homoclinic (heteroclinic) orbit is a kind of spiral structure. The emphasis is laid to show that there are homoclinic or heteroclinic orbits in complex discrete and continuous systems, and these homoclinic or heteroclinic orbits are some kind of spiral structure.展开更多
文摘Aim To present a quantitative method for structural complexity analysis and evaluation of information systems. Methods Based on Petri net modeling and analysis techniques and with the aid of mathematical tools in general net theory(GNT), a quantitative method for structure description and analysis of information systems was introduced. Results The structural complexity index and two related factors, i.e. element complexity factor and connection complexity factor were defined, and the relations between them and the parameters of the Petri net based model of the system were derived. Application example was presented. Conclusion The proposed method provides a theoretical basis for quantitative analysis and evaluation of the structural complexity and can be applied in the general planning and design processes of the information systems.
基金Supported by Science Foundation of Chuxiong Normal University(06YJRC19)National Natural Science Foundation of China(30760040)And Key Subject Construction of Chuxiong NormalUniversity(05YJJSXK03)~~
文摘The evolutionary trend of organisms, which often evolved from a simpler structure to a more complex structure, is a mystery. It seems that the later living things appeared on the earth, the more complex their structures were. This study pointed out that the evolutionary trend of organisms was the result of the organisms' asymmetric evolution-the phenomenon which the partition of the more complex structure was actually larger than that of the simpler structure on the same evolutionary platform of organisms, it explained the cause of the asymmetric evolution and listed much important evidence for organisms' asymmetric evolution.
基金Supported by Inner Mongolia Natural Science Foundation(200711020112)Innovation Fundation of Inner Mongolia University of Science and Technology (2009NC064)~~
文摘Based on protein-DNA complex crystal structural data in up-to-date Nucleic Acid Database,the related parameters of DNA Kinetic Structure were investigated by Monte-Carlo Multiple Integrals on the base of modified DNA structure statistical mechanical model,and time complexity and precision were analyzed on the calculated results.
基金The National Natural Science Foundation of China(No.60275016).
文摘Global semantic structures of two large semantic networks, HowNet and WordNet, are analyzed. It is found that they are both complex networks with features of small-world and scale-free, but with special properties. Exponents of power law degree distribution of these two networks are between 1.0 and 2. 0, different from most scale-free networks which have exponents near 3.0. Coefficients of degree correlation are lower than 0, similar to biological networks. The BA (Barabasi-Albert) model and other similar models cannot explain their dynamics. Relations between clustering coefficient and node degree obey scaling law, which suggests that there exist self-similar hierarchical structures in networks. The results suggest that structures of semantic networks are influenced by the ways we learn semantic knowledge such as aggregation and metaphor.
基金Supported in part by the National Natural Science Foundation of China(60073012),National Grand Fundamental Research 973 Program of China(G1999032701),Natural Research Foundation for the Doctoral Program of Higher Education of China,Natural Science Founda
文摘To provide system designer a valid measure to evaluate the structure complexityof class diagrams objectively, this letter first proposes a method to transform a class diagramsinto a weighted class dependence graph, then presents a structure complexity measure for classdiagrams based on entropy distance.
基金National Natural Science Foundation of China(No.61302159,61227003,61301259)Natural Science Foundation of Shanxi Province(No.2012021011-2)+2 种基金Specialized Research Fund for the Doctoral Program of Higher Education,China(No.20121420110006)Top Science and Technology Innovation Teams of Higher Learning Institutions of Shanxi Province,ChinaProject Sponsored by Scientific Research for the Returned Overseas Chinese Scholars,Shanxi Province(No.2013-083)
文摘The conventional X-ray gray weighted image fusion method based on variable energy cannot characterize the phys- ical properties of complicated objects correctly, therefore, the gray correction method of X-ray fusion image based on neural network is proposed. The conventional method acquires 12 bit images on variable energy, and then fuses the images in a tra- ditional way. While the new method takes the fusion image as the input of neural network simulation system and takes the acquired 16 bit image as the output of neural network. The X-ray image physical characteristic model based on neural net- work is obtained through training. And then it takes steel ladder block as the test object to verify the feasibility of the mod- el. In the end, the gray curve of output image is compared with the gray curve of 16 bit real image. The experiment results show that this method can fit the nonlinear relationship between the fusion image and the real image, and also can expand the scope of application of low dynamic image acquisition equipment.
基金support from the Centre for Integrated Petroleum Research(CIPR),University of Bergen, Norway,and Singapore MOE Grant T207B2202NRF2007IDMIDM002-010
文摘Segmentation of three-dimensional(3D) complicated structures is of great importance for many real applications.In this work we combine graph cut minimization method with a variant of the level set idea for 3D segmentation based on the Mumford-Shah model.Compared with the traditional approach for solving the Euler-Lagrange equation we do not need to solve any partial differential equations.Instead,the minimum cut on a special designed graph need to be computed.The method is tested on data with complicated structures.It is rather stable with respect to initial value and the algorithm is nearly parameter free.Experiments show that it can solve large problems much faster than traditional approaches.
基金supported by the National Natural Science Foundation of China(Nos.12172078,51576026)Fundamental Research Funds for the Central Universities in China(No.DUT21LK04)。
文摘Accurately solving transient nonlinear inverse heat conduction problems in complex structures is of great importance to provide key parameters for modeling coupled heat transfer process and the structure’s optimization design.The finite element method in ABAQUS is employed to solve the direct transient nonlinear heat conduction problem.Improved particle swarm optimization(PSO)method is developed and used to solve the transient nonlinear inverse problem.To investigate the inverse performances,some numerical tests are provided.Boundary conditions at inaccessible surfaces of a scramjet combustor with the regenerative cooling system are inversely identified.The results show that the new methodology can accurately and efficiently determine the boundary conditions in the scramjet combustor with the regenerative cooling system.By solving the transient nonlinear inverse problem,the improved particle swarm optimization for solving the transient nonlinear inverse heat conduction problem in a complex structure is verified.
基金Supported by the National Natural Science Foundation of China(No.61105086)Self-Planned Task(SKLRS-2010-MS-12)of State Key Laboratory of Robotics and System(HIT)Hubei Province Natural Science Foundation(No.2010CDB03405)
文摘In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large size, complex structure and poor low pressure atomization effect in comparison with requirement of snake-like fire rescue robots. On the basis of comprehensive typical spray noz- zles, a direct spiral double helix converging nozzle (DSDHCN) is proposed, which has the advanta- ges of small volume, light weight, simple structure, and convenient installation. To make the spray nozzle have good performance, and meet the requirements of more efficient fire extinguishing, a nu- merical study is carried out to analyze the internal and external full flow field of nozzle. A gas-liquid two-phase flow is applied to simulate the external full flow field of nozzle with VOF model in fluent software. The simulation results show the real situation of water flow out of the atomization nozzle and the water jet trajectory. Some simulations about middle or low water pressure direct spiral double he- lix converging optimized nozzle have been done in 30bar pressure. The simulation results show that the optimized nozzle structure not only makes the spray droplets have a good cone angle, but also have a sufficient axial velocity,which proves the structure rationality of the proposed optimized nozzle.
基金The Science and Technology Demonstration Project of Multimodal Freight Transport in Jiangsu Province(No.2018Y02).
文摘To explore the structural characteristics and vulnerability of multimodal transport networks,this study identifies the structural characteristics of a multimodal transport network on the basis of the complex network theory.Key nodes are clarified from the analysis of the structural characteristics.The characteristic path length and percentage of the largest subgraph are applied to analyze the vulnerability of the multimodal transport network after random and intentional attacks on the nodes.The network of a multimodal transport company is taken as an example in the empirical analysis.Results show that with more than ten nodes under a random attack,the percentage of the largest subgraph is less than 20%,and the characteristic path length is less than 2.The same performance is observed for more than seven nodes under an intentional attack.The multimodal transport network is more vulnerable under an international attack against key nodes.The results of the topology and node failure under random or intentional attacks would support the management of the multimodal transport network.Suggestions for the emergency transportation organization of enterprises under attacks are proposed accordingly.These suggestions should help improve network invulnerability and recovery from node failure.
基金National Science and Technology Support Program of China(No.2009BAG15B01)Key Programs for Science and Technology Development of Chinese Transportation Industry(No.2008-353-332-190)+2 种基金Natural Science Foundation of China(No.50708074)the Ministry of Science and Technology of China(No.SLDRCE08-B-04)Kwang-Hua Fund for College of Civil Engineering,Tongji University
文摘Taizhou Bridge is the first kilometer level three-pylon two-span suspension bridge in the world and the structural complexity has significant effects on the seismic performance of the bridge. Shaking table test of Taizhou Bridge is arranged to investigate the effects of non-uniform ground motion input, collision between main and side spans and optimal seismic structural system. It's very important and difficult to design and manufacture the scaled down model of Taizhou Bridge used during the shaking table test. The key point is that the girder and pylons are very hard to be manufactured if the similarity ratio is strictly followed. Based on the finite element method (FEM) analysis, a simplified scaled down model is designed and the bending stiffness of the girder and pylon are strictly simulated, and the torsion stiffness and axial stiffness are not strictly simulated. The inner forces and displacements of critical sections, points of simplified model and theoretical model are compared by FEM analysis, and it's found out that the difference between the seismic responses is relatively small. So, the simplified model can be used to conduct the shaking table test by the FEM verification.
基金Acknowledgements We thank Samantha Hilber for valuable comments on the manuscriPt. RMC thanks G.W. Barlow for countless discussions about behavior and for his unbounded enthusiasm for fishes.
文摘Aggressive behavior can be an important factor in determining how animals use and divide space and resources. Previous studies have shown that aggression in fishes can be influenced by a variety of factors, including water temperature and resource levels. In this study, we tested if the amount of habitat structure in the environment affected aggression levels in female convict cichlids Archocentrus nigrofasciatus. We performed a laboratory experiment in which we placed female convict cichlids into an aquarium with low or high amounts of habitat structure and monitored the dominant female's behavior toward the subordinate female. Aggressive behavior in convict cichlids primarily consists of chases and bites. We found that the total time the dominant female spent chasing the subordinate female was greater when there was a low amount of habitat structure as compared to when there was a high amount of habitat structure. We also found that both the average duration of a chasing bout and the number of bites directed at the subordinate fish increased when there was a low amount of structure, but the number of chases did not. These results indicate that increased habitat structural complexity decreases aggressive behavior in convict cichlids [Current Zoology 56 (1): 52-56, 2010].
基金supported by the Major Program of the National Natural Science Foundation of China(No.51490675)the National Natural Science Foundation of China(No.51479183)the Taishan Scholars Program of Shandong Province
文摘Offshore jacket platforms are widely used in offshore oil and gas exploitation.Finite element models of such structures need to have many degrees of freedom(DOFs) to represent the geometrical detail of complex structures,thereby leading to incompatibility in the number of DOFs of experimental models.To bring them both to the same order while ensuring that the essential eigen-properties of the refined model match those of experimental models,an extended model refinement procedure is presented in this paper.Vibration testing of an offshore jacket platform model is performed to validate the applicability of the proposed approach.A full-order finite element model of the platform is established and then tuned to meet the measured modal properties identified from the acceleration signals.Both model reduction and modal expansion methods are investigated,as well as various scenarios of sensor arrangements.Upon completion of the refinement,the updated jacket platform model matches the natural frequencies of the measured model well.
基金Supported by the National High Technology Research and Development Program of China (2012AA041102)the State Key Development Program for Basic Research of China (2012CB720500)
文摘Refinery system, a typical example of process systems, is presented as complex network in this paper. The topology of this system is described by task-resource network and modeled as directed and weighted graph, in which nodes represent various tasks and edges denote the resources exchanged among tasks. Using the properties of node degree distribution, strength distribution and other weighted quantities, we demonstrate the heterogeneity of the network and point out the relation between structural characters of vertices and the functionality of correspond- ing tasks. The above phenomena indicate that the design requirements and principles of production process contrib- ute to the heterogeneous features of the network. Besides, betweenness centrality of nodes can be used as an impor- tance indicator to provide additional information for decision making. The correlations between structure and weighted properties are investigated to further address the influence brought by production schemes in system con- nectivity patterns. Cascading failures model is employed to analyze the robustness of the network when targeted at- tack happens. Two capacity assignment strategies are compared in order to improve the robustness of the network at certain cost. The refinery system displays more reliable behavior when the protecting strategy considers heteroge- neous properties. This phenomenon further implies the structure-activity relationship of the refinery system and provides insightful suggestions for process system design. The results also indicate that robustness analysis is a _promising applicat!on of methodologies from complex networks to process system engineering..
基金Supported by the National Key Research and Development Program of China(No.2016YFB0201305)National Science and Technology Major Project(No.2013ZX0102-8001-001-001)National Natural Science Foundation of China(No.91430218,31327901,61472395,61272134,61432018)
文摘Clustering data with varying densities and complicated structures is important,while many existing clustering algorithms face difficulties for this problem. The reason is that varying densities and complicated structure make single algorithms perform badly for different parts of data. More intensive parts are assumed to have more information probably,an algorithm clustering from high density part is proposed,which begins from a tiny distance to find the highest density-connected partition and form corresponding super cores,then distance is iteratively increased by a global heuristic method to cluster parts with different densities. Mean of silhouette coefficient indicates the cluster performance. Denoising function is implemented to eliminate influence of noise and outliers. Many challenging experiments indicate that the algorithm has good performance on data with widely varying densities and extremely complex structures. It decides the optimal number of clusters automatically.Background knowledge is not needed and parameters tuning is easy. It is robust against noise and outliers.
文摘The International Civil Aviation Organization (ICAO) is a specialized agency of the United Nations. Functionally, it has emerged as the organizational necessity of both the universal complex structure and the importance of its overall activity. It was created on the basis of Article 57 of the United Nations Charter, stipulating that the specialized UN agencies are autonomous international organizations. They enjoy their autonomy on the basis of the contract they were established by, being engaged in activities within the United Nations system. On the territories the organization member states comprise, they enjoy privileges and immunities, having the international legal capacity to carry out their activities in accordance to the Statute. The 1944 Multilateral Convention was to establish both protection and efficient development of international civil aviation. In accordance to that rights and obligations of member states were established. It is of a special importance to emphasize obligation of parties to take their parts in both co-operation and programs aimed at improvement of international transport, navigational equipment, and installations. In the globalized world of today, air traffic is an irreplaceable part of the system of communication. It enables fast and timely business contacts between the people from various continents, as well as transport of goods.
文摘The nominal group is an important aspect of English and other languages and requires specific attention because of its complex structure and sequence. This study examines how sequencing affects users' understanding and interpretation of the English nominal group and attempts to prescribe guidelines to the different challenges which the complex ordering of the nominal group poses to users of English as a second language. The findings of the study indicate that the complex ordering of the nominal group has a significant impact on their semantic effects in any discourse, and many of the difficulties users of English as a second language are faced with have to do with lack of adequate understanding of the structure and usage of the nominal group. Some of these problems can be addressed through a comprehensive study and examination of linguists' explanation of the nominal group and practical application of their guidelines. A functional approach to the study of the group will help second language learners of English to have a better understanding of its structure
基金Supported by the National Natural Science Foundation of China (No. 61101159, 60872123), the China Postdoctoral Science Foundation (No. 20100480049) and the Fundamental Research Funds for the Central Universities (No. 201 IZM0033)
文摘It is a fairly challenging issue to make image repositories easy to be searched and browsed. This depends on a technique--image clustering. Kernel-based clustering algorithm has been one of the most promising clustering methods in the last few years, beeanse it can handle data with high dimensional complex structure. In this paper, a kernel fuzzy learning (KFL) algorithm is proposed, which takes advantages of the distance kernel trick and the gradient-based fuzzy clustering method to execute the image clustering automatically. Experimental results show that KFL is a more efficient method for image clustering in comparison with recent renorted alternative methods.
文摘Starting from iterated systems, it is shown that the homoclinic (heteroclinic) orbit is a kind of spiral structure. The emphasis is laid to show that there are homoclinic or heteroclinic orbits in complex discrete and continuous systems, and these homoclinic or heteroclinic orbits are some kind of spiral structure.