The accuracy and effi ciency of the modelling techniques utilized to model the nonlinear behavior of structural components is a signifi cant issue in earthquake engineering. In this study, the suffi ciency of three di...The accuracy and effi ciency of the modelling techniques utilized to model the nonlinear behavior of structural components is a signifi cant issue in earthquake engineering. In this study, the suffi ciency of three diff erent modelling techniques that can be employed to simulate the structural behavior of columns is investigated. A fi ber-based fi nite length plastic hinge (FB-FLPH) model is calibrated in this study. In order to calibrate the FB-FLPH model, a novel database of the cyclic behavior of hollow steel columns under simultaneous axial and lateral loading cycles with varying amplitudes is used. By employing the FB-FLPH model calibrated in this study, the interaction of the axial force and the bending moment in columns is directly taken into account, and the deterioration in the cyclic behavior of these members is implicitly considered. The superiority of the calibrated FB-FLPH modelling approach is examined compared with the cases in which conventional fi ber-based distributed plasticity and concentrated plasticity models are utilized. The effi ciency of the enumerated modelling techniques is probed when they are implemented to model the columns of a typical special moment frame in order to prove the advantage of the FB-FLPH modelling approach.展开更多
Future communication systems will include di erent types of messages requiring di erent transmission rates,packet lengths,and service qualities.We address the power-optimization issues of communication systems conveyi...Future communication systems will include di erent types of messages requiring di erent transmission rates,packet lengths,and service qualities.We address the power-optimization issues of communication systems conveying multiple message types based on nite-delay information theory.Given both the normalized transmission rate and the packet length of a system,the actual residual decoding error rate is a function of the transmission power.We propose a generalized power allocation framework for multiple message types.Two di erent optimization cost functions are adopted:the number of service-quality violations encountered and the sum log ratio of the residual decoding error rate.We provide the optimal analytical solution for the former cost function and a heuristic solution based on a genetic algorithm for the latter one.Finally,the performance of the proposed solutions are evaluated numerically.展开更多
In order to improve rolled strip quality, precise plate shape control theory should be established. Roll flat- tening theory is an important part of the plate shape theory. To improve the accuracy of roll flattening c...In order to improve rolled strip quality, precise plate shape control theory should be established. Roll flat- tening theory is an important part of the plate shape theory. To improve the accuracy of roll flattening calculation based on semi infinite body model, especially near the two roll barrel edges, a new and more accurate roll flattening model is proposed. Based on boundary integral equation method, an analytical model for solving a finite length semi infinite body is established. The lateral surface displacement field of the finite length semi-infinite body is simulated by finite element method （FEM） and lateral surface displacement decay functions are established. Based on the boundary integral equation method, the numerical solution of the finite length semi-infinite body under the distribu ted force is obtained and an accurate roll flattening model is established. Different from the traditional semi-infinite body model, the matrix form of the new roll flattening model is established through the mathematical derivation. The result from the new model is more consistent with that by FEM especially near the edges.展开更多
文摘The accuracy and effi ciency of the modelling techniques utilized to model the nonlinear behavior of structural components is a signifi cant issue in earthquake engineering. In this study, the suffi ciency of three diff erent modelling techniques that can be employed to simulate the structural behavior of columns is investigated. A fi ber-based fi nite length plastic hinge (FB-FLPH) model is calibrated in this study. In order to calibrate the FB-FLPH model, a novel database of the cyclic behavior of hollow steel columns under simultaneous axial and lateral loading cycles with varying amplitudes is used. By employing the FB-FLPH model calibrated in this study, the interaction of the axial force and the bending moment in columns is directly taken into account, and the deterioration in the cyclic behavior of these members is implicitly considered. The superiority of the calibrated FB-FLPH modelling approach is examined compared with the cases in which conventional fi ber-based distributed plasticity and concentrated plasticity models are utilized. The effi ciency of the enumerated modelling techniques is probed when they are implemented to model the columns of a typical special moment frame in order to prove the advantage of the FB-FLPH modelling approach.
基金This work is supported by the National Key Basic Research Program of China(No.2013CB329201)Key Program of Na-tional Natural Science Foundation of China(No.61631018)+3 种基金Key Research Program of Frontier Sciences of CAS(No.QYZDY-SSW-JSC003)Key Project in Science and Technology of Guangdong Province(No.2014B010119001)Shenzhen Peacock Plan(No.1108170036003286)the Fundamental Research Funds for the Central Universities.
文摘Future communication systems will include di erent types of messages requiring di erent transmission rates,packet lengths,and service qualities.We address the power-optimization issues of communication systems conveying multiple message types based on nite-delay information theory.Given both the normalized transmission rate and the packet length of a system,the actual residual decoding error rate is a function of the transmission power.We propose a generalized power allocation framework for multiple message types.Two di erent optimization cost functions are adopted:the number of service-quality violations encountered and the sum log ratio of the residual decoding error rate.We provide the optimal analytical solution for the former cost function and a heuristic solution based on a genetic algorithm for the latter one.Finally,the performance of the proposed solutions are evaluated numerically.
基金Item Sponsored by National Natural Science Foundation of China(51075353)
文摘In order to improve rolled strip quality, precise plate shape control theory should be established. Roll flat- tening theory is an important part of the plate shape theory. To improve the accuracy of roll flattening calculation based on semi infinite body model, especially near the two roll barrel edges, a new and more accurate roll flattening model is proposed. Based on boundary integral equation method, an analytical model for solving a finite length semi infinite body is established. The lateral surface displacement field of the finite length semi-infinite body is simulated by finite element method （FEM） and lateral surface displacement decay functions are established. Based on the boundary integral equation method, the numerical solution of the finite length semi-infinite body under the distribu ted force is obtained and an accurate roll flattening model is established. Different from the traditional semi-infinite body model, the matrix form of the new roll flattening model is established through the mathematical derivation. The result from the new model is more consistent with that by FEM especially near the edges.
