In order to improve the data throughput of the advanced encryption standard (AES) IP core while reducing the hardware resource consumption and finally achieving a tradeoff between speed and area, a mixed pipeline ar...In order to improve the data throughput of the advanced encryption standard (AES) IP core while reducing the hardware resource consumption and finally achieving a tradeoff between speed and area, a mixed pipeline architecture and reconfigurable technology for the design and implementation of the AES IP core is proposed. The encryption and decryption processes of the AES algorithm are achieved in the same process within the mixed pipeline structure. According to the finite field characterizations, the Sbox in the AES algorithm is optimized. ShiftRow and MixColumn, which are the main components in AES round transformation, are optimized with the reconfigurable technology. The design is implemented on the Xilinx Virtex2p xc2vp20-7 field programmable gate array (FPGA) device. It can achieve a data throughput above 2.58 Gbit/s, and it only requires 3 233 slices. Compared with other related designs of AES IP cores on the same device, the proposed design can achieve a tradeoff between speed and area, and obtain satisfactory results in both data throughput and hardware resource consumption.展开更多
The ordered weighted geometric averaging(OWGA) operator is extended to accommodate uncertain conditions where all input arguments take the forms of interval numbers. First, a possibility degree formula for the compa...The ordered weighted geometric averaging(OWGA) operator is extended to accommodate uncertain conditions where all input arguments take the forms of interval numbers. First, a possibility degree formula for the comparison between interval numbers is introduced. It is proved that the introduced formula is equivalent to the existing formulae, and also some desired properties of the possibility degree is presented. Secondly, the uncertain OWGA operator is investigated in which the associated weighting parameters cannot be specified, but value ranges can be obtained and the associated aggregated values of an uncertain OWGA operator are known. A linear objective-programming model is established; by solving this model, the associated weights vector of an uncertain OWGA operator can be determined, and also the estimated aggregated values of the alternatives can be obtained. Then the alternatives can be ranked by the comparison of the estimated aggregated values using the possibility degree formula. Finally, a numerical example is given to show the feasibility and effectiveness of the developed method.展开更多
On the basis of analysing the reliability problems existing in the general design of a kind of multioption fuze. some problems such as the reliability model. the reliability distribution of the electronic part of the ...On the basis of analysing the reliability problems existing in the general design of a kind of multioption fuze. some problems such as the reliability model. the reliability distribution of the electronic part of the fuze are discussed. For a particular multioption fuze, then.according to three different setting ways. the calculating methods of its operating reliability in six different operating states are given.展开更多
A multi-component system has the long fixed maintenance time, so the opportunistic maintenance policy is adopted to put preventive replacement and corrective replacement together, so that the long fixed maintenance ti...A multi-component system has the long fixed maintenance time, so the opportunistic maintenance policy is adopted to put preventive replacement and corrective replacement together, so that the long fixed maintenance time can be shared by more than one component, and the system availability can be improved. Then, the generation characteristics of the random failure time are researched based on the replacement maintenance and the minima[ maintenance. Furthermore, by choosing the opportunistic replacement ages of each component as opti- mized variables, a simulation algorithm based on an opportunistic maintenance policy is designed to maximize the total availability. Finally, the simulation result shows the validity of the algorithm by an example.展开更多
In this paper, a computer visualization approach is proposed for electromagnetic wave interaction with structures by mains of finite difference-time doain method (F-D) and computer graphics. By visualization of FDTD, ...In this paper, a computer visualization approach is proposed for electromagnetic wave interaction with structures by mains of finite difference-time doain method (F-D) and computer graphics. By visualization of FDTD, Phenomena such as wave propagation, penetration through structures, renection and absorption by structures are observed. Visualization of electromagnetic wave interactions with two wing-shaped structures is demonstrated. These examples indicate that the approach describe in the paper offers an effective way for investigating electromagnetic wave phenomena and is helpful to the engineers in controlling radar signature of the targets.展开更多
A single-machine scheduling with preventive periodic maintenance activities in a remanufacturing system including resumable and non-resumable jobs is studied.The objective is to find a schedule to minimize the makespa...A single-machine scheduling with preventive periodic maintenance activities in a remanufacturing system including resumable and non-resumable jobs is studied.The objective is to find a schedule to minimize the makespan and an LPT-LS algorithm is proposed.Non-resumable jobs are first scheduled in a machine by the longest processing time(LPT) rule,and then resumable jobs are scheduled by the list scheduling(LS) rule.And the worst-case ratios of this algorithm in three different cases in terms of the value of the total processing time of the resumable jobs(denoted as S2) are discussed.When S2 is longer than the spare time of the machine after the non-resumable jobs are assigned by the LPT rule,it is equal to 1.When S2 falls in between the spare time of the machine by the LPT rule and the optimal schedule rule,it is less than 2.When S2 is less than the spare time of the machine by the optimal schedule rule,it is less than 2.Finally,numerical examples are presented for verification.展开更多
In order to decrease the calculation complexity of connectivity reliability of road networks, an improved recursive decomposition arithmetic is proposed. First, the basic theory of recursive decomposition arithmetic i...In order to decrease the calculation complexity of connectivity reliability of road networks, an improved recursive decomposition arithmetic is proposed. First, the basic theory of recursive decomposition arithmetic is reviewed. Then the characteristics of road networks, which are different from general networks, are analyzed. Under this condition, an improved recursive decomposition arithmetic is put forward which fits road networks better. Furthermore, detailed calculation steps are presented which are convenient for the computer, and the advantage of the approximate arithmetic is analyzed based on this improved arithmetic. This improved recursive decomposition arithmetic directly produces disjoint minipaths and avoids the non-polynomial increasing problems. And because the characteristics of road networks are considered, this arithmetic is greatly simplified. Finally, an example is given to prove its validity.展开更多
The flow around airfoil NACA0012 enwrapped by the body-fitted grid is simulated by a coupled doubledistribution-function (DDF) lattice Boltzmann method (LBM) for the compressible Navier-Stokes equations. Firstly, ...The flow around airfoil NACA0012 enwrapped by the body-fitted grid is simulated by a coupled doubledistribution-function (DDF) lattice Boltzmann method (LBM) for the compressible Navier-Stokes equations. Firstly, the method is tested by simulating the low Reynolds number flow at Ma =0. 5,a=0. 0, Re=5 000. Then the simulation of flow around the airfoil is carried out at Ma:0. 5, 0. 85, 1.2; a=-0.05, 1.0, 0.0, respectively. And a better result is obtained by using a local refined grid. It reduces the error produced by the grid at Ma=0. 85. Though the inviscid boundary condition is used to avoid the problem of flow transition to turbulence at high Reynolds numbers, the pressure distribution obtained by the simulation agrees well with that of the experimental results. Thus, it proves the reliability of the method and shows its potential for the compressible flow simulation. The suecessful application to the flow around airfoil lays a foundation of the numerical simulation of turbulence.展开更多
As the tableau algorithm would produce a lot of description overlaps when judging the satisfiabilities of concepts(thus wasting much space),a clause-based enhancing mode designed for the language ALCN is proposed.Th...As the tableau algorithm would produce a lot of description overlaps when judging the satisfiabilities of concepts(thus wasting much space),a clause-based enhancing mode designed for the language ALCN is proposed.This enhancing mode constructs a disjunctive normal form on concept expressions and keeps only one conjunctive clause,and then substitutes the obtained succinctest conjunctive clause for sub-concepts set in the labeling of nodes of a completion tree constructed by the tableau algorithm (such a process may be repeated as many times as needed).Due to the avoidance of tremendous descriptions redundancies caused by applying ∩- and ∪-rules of the ordinary tableau algorithm,this mode greatly improves the spatial performance as a result.An example is given to demonstrate the application of this enhancing mode and its reduction in the cost of space. Results show that the improvement is very outstanding.展开更多
Based on the analysis to the random sear ch algorithm of LUUS, a modified random directed integer search algorithm (MRDI SA) is given for first time. And a practical example is given to show that the adva ntage of th...Based on the analysis to the random sear ch algorithm of LUUS, a modified random directed integer search algorithm (MRDI SA) is given for first time. And a practical example is given to show that the adva ntage of this kind of algorithm is the reliability can’t be infuenced by the ini tial value X (0) and the start search domain R (0) . Besides, i t can be applied to solve the higher dimensional constrained nonlinear integer p rogramming problem.展开更多
To diagnose the feasibility of the solution of a job-shop scheduling problem(JSSP),a test algorithm based on diagraph and heuristic search is developed and verified through a case study.Meanwhile,a new repair algori...To diagnose the feasibility of the solution of a job-shop scheduling problem(JSSP),a test algorithm based on diagraph and heuristic search is developed and verified through a case study.Meanwhile,a new repair algorithm for modifying an infeasible solution of the JSSP to become a feasible solution is proposed for the general JSSP.The computational complexity of the test algorithm and the repair algorithm is both O(n) under the worst-case scenario,and O(2J+M) for the repair algorithm under the best-case scenario.The repair algorithm is not limited to specific optimization methods,such as local tabu search,genetic algorithms and shifting bottleneck procedures for job shop scheduling,but applicable to generic infeasible solutions for the JSSP to achieve feasibility.展开更多
A new method to accelerate the convergent rate of the space-alternatinggeneralized expectation-maximization (SAGE) algorithm is proposed. The new rescaled block-iterativeSAGE (RBI-SAGE) algorithm combines the RBI algo...A new method to accelerate the convergent rate of the space-alternatinggeneralized expectation-maximization (SAGE) algorithm is proposed. The new rescaled block-iterativeSAGE (RBI-SAGE) algorithm combines the RBI algorithm with the SAGE algorithm for PET imagereconstruction. In the new approach, the projection data is partitioned into disjoint blocks; eachiteration step involves only one of these blocks. SAGE updates the parameters sequentially in eachblock. In experiments, the RBI-SAGE algorithm and classical SAGE algorithm are compared in theapplication on positron emission tomography (PET) image reconstruction. Simulation results show thatRBI-SAGE has better performance than SAGE in both convergence and image quality.展开更多
In present paper, we obtain the inverse moment estimations of parameters of the Birnbaum-Saunders fatigue life distribution based on Type-Ⅱ bilateral censored samples and multiply Type-Ⅱ censored sample. In this pap...In present paper, we obtain the inverse moment estimations of parameters of the Birnbaum-Saunders fatigue life distribution based on Type-Ⅱ bilateral censored samples and multiply Type-Ⅱ censored sample. In this paper, we also get the interval estimations of the scale parameters.展开更多
For the computability of co-regular subsets in metric spaces, the properties of the co-regular subsets and several reasonable representations on co-regular sets have been suggested in this paper. As last, the 'weaker...For the computability of co-regular subsets in metric spaces, the properties of the co-regular subsets and several reasonable representations on co-regular sets have been suggested in this paper. As last, the 'weaker or stronger' relations of these representations have been revealed.展开更多
A numerical procedure for reliability analysis of earth slope based on advanced first-order second-moment method is presented,while soil properties and pore water pressure may be considered as random variables.The fac...A numerical procedure for reliability analysis of earth slope based on advanced first-order second-moment method is presented,while soil properties and pore water pressure may be considered as random variables.The factor of safety and performance function is formulated utilizing a new approach of the Morgenstern and Price method.To evaluate the minimum reliability index defined by Hasofer and Lind and corresponding critical probabilistic slip surface,a hybrid algorithm combining chaotic particle swarm optimization and harmony search algorithm called CPSOHS is presented.The comparison of the results of the presented method,standard particle swarm optimization,and selected other methods employed in previous studies demonstrates the superior successful functioning of the new method by evaluating lower values of reliability index and factor of safety.Moreover,the presented procedure is applied for sensitivity analysis and the obtained results show the influence of soil strength parameters and probability distribution types of random variables on the reliability index of slopes.展开更多
Topology aggregation is necessary for scalable QoS routing mechanisms. Thekey issue is how to gain good performance while summarizing the topological information. In thispaper, we propose a new method to describe the ...Topology aggregation is necessary for scalable QoS routing mechanisms. Thekey issue is how to gain good performance while summarizing the topological information. In thispaper, we propose a new method to describe the logical link, which is simple and effective innetwork with additive and constrained concave parameters. We extend the method to network associatedwith multi-parameters. Furthermore, we propose a modified star aggregation algorithm. Simulationsare used to evaluate the performance. The results show that our algorithm is relatively good.展开更多
High computational performance is extremely important for climate system models, especially in ultra-high-resolution model development. In this study, the computational performance of the Finite-volume Atmospheric Mod...High computational performance is extremely important for climate system models, especially in ultra-high-resolution model development. In this study, the computational performance of the Finite-volume Atmospheric Model of the IAP/LASG (FAMIL) was comprehensively evaluated on Tianhe-2, which was the world's top-ranked supercomputer from June 2013 to May 2016. The standardized Atmospheric Model Inter-comparison Project (AMIP) type of experiment was carried out that focused on the computational performance of each node as well as the simulation year per day (SYPD), the running cost speedup, and the scalability of the FAMIL. The results indicated that (1) based on five indexes (CPU usage, percentage of CPU kernel mode that occupies CPU time and of message passing waiting time (CPU SW), code vectorization (VEC), average of Gflops (Gflops_ AVE), and peak of Gflops (Gflops_PK)), FAMIL shows excellent computational performance on every Tianhe-2 computing node; (2) considering SYPD and the cost speedup of FAMIL systematically, the optimal Message Passing Interface (MPI) numbers of processors (MNPs) choice appears when FAMIL use 384 and 1536 MNPs for C96 (100 km) and C384 (25 km), respectively; and (3) FAMIL shows positive scalability with increased threads to drive the model. Considering the fast network speed and acceleration card in the MIC architecture on Tianhe-2, there is still significant room to improve the computational performance of FAMIL.展开更多
To overcome the drawbacks such as irregular circuit construction and low system throughput that exist in conventional methods, a new factor correction scheme for coordinate rotation digital computer( CORDIC) algorit...To overcome the drawbacks such as irregular circuit construction and low system throughput that exist in conventional methods, a new factor correction scheme for coordinate rotation digital computer( CORDIC) algorithm is proposed. Based on the relationship between the iteration formulae, a new iteration formula is introduced, which leads the correction operation to be several simple shifting and adding operations. As one key part, the effects caused by rounding error are analyzed mathematically and it is concluded that the effects can be degraded by an appropriate selection of coefficients in the iteration formula. The model is then set up in Matlab and coded in Verilog HDL language. The proposed algorithm is also synthesized and verified in field-programmable gate array (FPGA). The results show that this new scheme requires only one additional clock cycle and there is no change in the elementary iteration for the same precision compared with the conventional algorithm. In addition, the circuit realization is regular and the change in system throughput is very minimal.展开更多
文摘In order to improve the data throughput of the advanced encryption standard (AES) IP core while reducing the hardware resource consumption and finally achieving a tradeoff between speed and area, a mixed pipeline architecture and reconfigurable technology for the design and implementation of the AES IP core is proposed. The encryption and decryption processes of the AES algorithm are achieved in the same process within the mixed pipeline structure. According to the finite field characterizations, the Sbox in the AES algorithm is optimized. ShiftRow and MixColumn, which are the main components in AES round transformation, are optimized with the reconfigurable technology. The design is implemented on the Xilinx Virtex2p xc2vp20-7 field programmable gate array (FPGA) device. It can achieve a data throughput above 2.58 Gbit/s, and it only requires 3 233 slices. Compared with other related designs of AES IP cores on the same device, the proposed design can achieve a tradeoff between speed and area, and obtain satisfactory results in both data throughput and hardware resource consumption.
基金The Technological Innovation Foundation of NanjingForestry University(No.163060033).
文摘The ordered weighted geometric averaging(OWGA) operator is extended to accommodate uncertain conditions where all input arguments take the forms of interval numbers. First, a possibility degree formula for the comparison between interval numbers is introduced. It is proved that the introduced formula is equivalent to the existing formulae, and also some desired properties of the possibility degree is presented. Secondly, the uncertain OWGA operator is investigated in which the associated weighting parameters cannot be specified, but value ranges can be obtained and the associated aggregated values of an uncertain OWGA operator are known. A linear objective-programming model is established; by solving this model, the associated weights vector of an uncertain OWGA operator can be determined, and also the estimated aggregated values of the alternatives can be obtained. Then the alternatives can be ranked by the comparison of the estimated aggregated values using the possibility degree formula. Finally, a numerical example is given to show the feasibility and effectiveness of the developed method.
文摘On the basis of analysing the reliability problems existing in the general design of a kind of multioption fuze. some problems such as the reliability model. the reliability distribution of the electronic part of the fuze are discussed. For a particular multioption fuze, then.according to three different setting ways. the calculating methods of its operating reliability in six different operating states are given.
文摘A multi-component system has the long fixed maintenance time, so the opportunistic maintenance policy is adopted to put preventive replacement and corrective replacement together, so that the long fixed maintenance time can be shared by more than one component, and the system availability can be improved. Then, the generation characteristics of the random failure time are researched based on the replacement maintenance and the minima[ maintenance. Furthermore, by choosing the opportunistic replacement ages of each component as opti- mized variables, a simulation algorithm based on an opportunistic maintenance policy is designed to maximize the total availability. Finally, the simulation result shows the validity of the algorithm by an example.
文摘In this paper, a computer visualization approach is proposed for electromagnetic wave interaction with structures by mains of finite difference-time doain method (F-D) and computer graphics. By visualization of FDTD, Phenomena such as wave propagation, penetration through structures, renection and absorption by structures are observed. Visualization of electromagnetic wave interactions with two wing-shaped structures is demonstrated. These examples indicate that the approach describe in the paper offers an effective way for investigating electromagnetic wave phenomena and is helpful to the engineers in controlling radar signature of the targets.
基金The National Natural Science Foundation of China (No.70971022,71271054)the Scientific Research Innovation Project for College Graduates in Jiangsu Province(No.CXLX_0157)the Scientific Research Foundation of the Education Department of Anhui Province(No.2011sk123)
文摘A single-machine scheduling with preventive periodic maintenance activities in a remanufacturing system including resumable and non-resumable jobs is studied.The objective is to find a schedule to minimize the makespan and an LPT-LS algorithm is proposed.Non-resumable jobs are first scheduled in a machine by the longest processing time(LPT) rule,and then resumable jobs are scheduled by the list scheduling(LS) rule.And the worst-case ratios of this algorithm in three different cases in terms of the value of the total processing time of the resumable jobs(denoted as S2) are discussed.When S2 is longer than the spare time of the machine after the non-resumable jobs are assigned by the LPT rule,it is equal to 1.When S2 falls in between the spare time of the machine by the LPT rule and the optimal schedule rule,it is less than 2.When S2 is less than the spare time of the machine by the optimal schedule rule,it is less than 2.Finally,numerical examples are presented for verification.
基金The National Key Technology R& D Program of Chinaduring the 11th Five-Year Plan Period (No.2006BAJ18B03).
文摘In order to decrease the calculation complexity of connectivity reliability of road networks, an improved recursive decomposition arithmetic is proposed. First, the basic theory of recursive decomposition arithmetic is reviewed. Then the characteristics of road networks, which are different from general networks, are analyzed. Under this condition, an improved recursive decomposition arithmetic is put forward which fits road networks better. Furthermore, detailed calculation steps are presented which are convenient for the computer, and the advantage of the approximate arithmetic is analyzed based on this improved arithmetic. This improved recursive decomposition arithmetic directly produces disjoint minipaths and avoids the non-polynomial increasing problems. And because the characteristics of road networks are considered, this arithmetic is greatly simplified. Finally, an example is given to prove its validity.
基金Supported by the Aeronautical Science Foundation of China(20061453020)Foundation for Basic Research of Northwestern Polytechnical University(03)~~
文摘The flow around airfoil NACA0012 enwrapped by the body-fitted grid is simulated by a coupled doubledistribution-function (DDF) lattice Boltzmann method (LBM) for the compressible Navier-Stokes equations. Firstly, the method is tested by simulating the low Reynolds number flow at Ma =0. 5,a=0. 0, Re=5 000. Then the simulation of flow around the airfoil is carried out at Ma:0. 5, 0. 85, 1.2; a=-0.05, 1.0, 0.0, respectively. And a better result is obtained by using a local refined grid. It reduces the error produced by the grid at Ma=0. 85. Though the inviscid boundary condition is used to avoid the problem of flow transition to turbulence at high Reynolds numbers, the pressure distribution obtained by the simulation agrees well with that of the experimental results. Thus, it proves the reliability of the method and shows its potential for the compressible flow simulation. The suecessful application to the flow around airfoil lays a foundation of the numerical simulation of turbulence.
基金The National Natural Science Foundation of China(No.60775029)the Science and Technology Program of Zhejiang Province(No.2007C33072)
文摘As the tableau algorithm would produce a lot of description overlaps when judging the satisfiabilities of concepts(thus wasting much space),a clause-based enhancing mode designed for the language ALCN is proposed.This enhancing mode constructs a disjunctive normal form on concept expressions and keeps only one conjunctive clause,and then substitutes the obtained succinctest conjunctive clause for sub-concepts set in the labeling of nodes of a completion tree constructed by the tableau algorithm (such a process may be repeated as many times as needed).Due to the avoidance of tremendous descriptions redundancies caused by applying ∩- and ∪-rules of the ordinary tableau algorithm,this mode greatly improves the spatial performance as a result.An example is given to demonstrate the application of this enhancing mode and its reduction in the cost of space. Results show that the improvement is very outstanding.
文摘Based on the analysis to the random sear ch algorithm of LUUS, a modified random directed integer search algorithm (MRDI SA) is given for first time. And a practical example is given to show that the adva ntage of this kind of algorithm is the reliability can’t be infuenced by the ini tial value X (0) and the start search domain R (0) . Besides, i t can be applied to solve the higher dimensional constrained nonlinear integer p rogramming problem.
基金The US National Science Foundation (No. CMMI-0408390, CMMI-0644552)the Research Fellowship for International Young Scientists (No. 51050110143)+2 种基金the Fok Ying-Tong Education Foundation(No. 114024)the Natural Science Foundation of Jiangsu Province (No.BK2009015)the Postdoctoral Science Foundation of Jiangsu Province (No.0901005C)
文摘To diagnose the feasibility of the solution of a job-shop scheduling problem(JSSP),a test algorithm based on diagraph and heuristic search is developed and verified through a case study.Meanwhile,a new repair algorithm for modifying an infeasible solution of the JSSP to become a feasible solution is proposed for the general JSSP.The computational complexity of the test algorithm and the repair algorithm is both O(n) under the worst-case scenario,and O(2J+M) for the repair algorithm under the best-case scenario.The repair algorithm is not limited to specific optimization methods,such as local tabu search,genetic algorithms and shifting bottleneck procedures for job shop scheduling,but applicable to generic infeasible solutions for the JSSP to achieve feasibility.
文摘A new method to accelerate the convergent rate of the space-alternatinggeneralized expectation-maximization (SAGE) algorithm is proposed. The new rescaled block-iterativeSAGE (RBI-SAGE) algorithm combines the RBI algorithm with the SAGE algorithm for PET imagereconstruction. In the new approach, the projection data is partitioned into disjoint blocks; eachiteration step involves only one of these blocks. SAGE updates the parameters sequentially in eachblock. In experiments, the RBI-SAGE algorithm and classical SAGE algorithm are compared in theapplication on positron emission tomography (PET) image reconstruction. Simulation results show thatRBI-SAGE has better performance than SAGE in both convergence and image quality.
基金Supported by the NSF of China(69971016) Supported by the Shanghai Higher Learning Science Supported by the Technology Development Foundation(00JC14507)
文摘In present paper, we obtain the inverse moment estimations of parameters of the Birnbaum-Saunders fatigue life distribution based on Type-Ⅱ bilateral censored samples and multiply Type-Ⅱ censored sample. In this paper, we also get the interval estimations of the scale parameters.
文摘For the computability of co-regular subsets in metric spaces, the properties of the co-regular subsets and several reasonable representations on co-regular sets have been suggested in this paper. As last, the 'weaker or stronger' relations of these representations have been revealed.
基金supported by the Ministry of Higher Education, Malaysia (Grant No.UKM-AP-PLW-04-2009/2)
文摘A numerical procedure for reliability analysis of earth slope based on advanced first-order second-moment method is presented,while soil properties and pore water pressure may be considered as random variables.The factor of safety and performance function is formulated utilizing a new approach of the Morgenstern and Price method.To evaluate the minimum reliability index defined by Hasofer and Lind and corresponding critical probabilistic slip surface,a hybrid algorithm combining chaotic particle swarm optimization and harmony search algorithm called CPSOHS is presented.The comparison of the results of the presented method,standard particle swarm optimization,and selected other methods employed in previous studies demonstrates the superior successful functioning of the new method by evaluating lower values of reliability index and factor of safety.Moreover,the presented procedure is applied for sensitivity analysis and the obtained results show the influence of soil strength parameters and probability distribution types of random variables on the reliability index of slopes.
文摘Topology aggregation is necessary for scalable QoS routing mechanisms. Thekey issue is how to gain good performance while summarizing the topological information. In thispaper, we propose a new method to describe the logical link, which is simple and effective innetwork with additive and constrained concave parameters. We extend the method to network associatedwith multi-parameters. Furthermore, we propose a modified star aggregation algorithm. Simulationsare used to evaluate the performance. The results show that our algorithm is relatively good.
基金supported by the National Natural Science Foundation of China[grant number 41675100],[grant number91337110]the Third Tibetan Plateau Scientific Experiment:Observations for Boundary Layer and Troposphere[GYHY201406001]+1 种基金the Key Research Program of Frontier Sciences,Chinese Academy of Science(CAS)(QYZDY-SSW-DQC018)the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(the 2nd phase)
文摘High computational performance is extremely important for climate system models, especially in ultra-high-resolution model development. In this study, the computational performance of the Finite-volume Atmospheric Model of the IAP/LASG (FAMIL) was comprehensively evaluated on Tianhe-2, which was the world's top-ranked supercomputer from June 2013 to May 2016. The standardized Atmospheric Model Inter-comparison Project (AMIP) type of experiment was carried out that focused on the computational performance of each node as well as the simulation year per day (SYPD), the running cost speedup, and the scalability of the FAMIL. The results indicated that (1) based on five indexes (CPU usage, percentage of CPU kernel mode that occupies CPU time and of message passing waiting time (CPU SW), code vectorization (VEC), average of Gflops (Gflops_ AVE), and peak of Gflops (Gflops_PK)), FAMIL shows excellent computational performance on every Tianhe-2 computing node; (2) considering SYPD and the cost speedup of FAMIL systematically, the optimal Message Passing Interface (MPI) numbers of processors (MNPs) choice appears when FAMIL use 384 and 1536 MNPs for C96 (100 km) and C384 (25 km), respectively; and (3) FAMIL shows positive scalability with increased threads to drive the model. Considering the fast network speed and acceleration card in the MIC architecture on Tianhe-2, there is still significant room to improve the computational performance of FAMIL.
基金The National High Technology Research and Development Program of China (863 Program)(No.2007AA01Z280)
文摘To overcome the drawbacks such as irregular circuit construction and low system throughput that exist in conventional methods, a new factor correction scheme for coordinate rotation digital computer( CORDIC) algorithm is proposed. Based on the relationship between the iteration formulae, a new iteration formula is introduced, which leads the correction operation to be several simple shifting and adding operations. As one key part, the effects caused by rounding error are analyzed mathematically and it is concluded that the effects can be degraded by an appropriate selection of coefficients in the iteration formula. The model is then set up in Matlab and coded in Verilog HDL language. The proposed algorithm is also synthesized and verified in field-programmable gate array (FPGA). The results show that this new scheme requires only one additional clock cycle and there is no change in the elementary iteration for the same precision compared with the conventional algorithm. In addition, the circuit realization is regular and the change in system throughput is very minimal.