A series of single hole blasting crater experiments and a variable distance multi-hole simultaneous blasting experiment was carried in the Yunfu Troilite Mine,according to the Livingston blasting crater theory.We intr...A series of single hole blasting crater experiments and a variable distance multi-hole simultaneous blasting experiment was carried in the Yunfu Troilite Mine,according to the Livingston blasting crater theory.We introduce in detail,our methodology of data collection and processing from our experiments.Based on the burying depth of the explosives,the blasting crater volume was fitted by the method of least squares and the characteristic curve of the blasting crater was obtained using the MATLAB soft- ware.From this third degree polynomial,we have derived the optimal burying depth,the critical burying depth and the optimal explosive specific charge of the blasting crater.展开更多
Battery energy storage systems(BESSs)can provide instantaneous support for frequency regulation(FR)because of their fast response characteristics.However,purely pursuing a better FR effect calls for continually rapid ...Battery energy storage systems(BESSs)can provide instantaneous support for frequency regulation(FR)because of their fast response characteristics.However,purely pursuing a better FR effect calls for continually rapid cycles of BESSs,which shortens their lifetime and deteriorates the operational economy.To coordinate the lifespan savings and the FR effect,this paper presents a control strategy for the FR of BESSs based on fuzzy logic and hierarchical controllers.The fuzzy logic controller improves the effect of FR by adjusting the charging/discharging power of the BESS with a higher response speed and precision based on the area control error(ACE)signal and the change rate of ACE in a non-linear way.Hierarchical controllers effectively reduce the life loss by optimizing the depth of discharge,which ensures that the state of charge(SOC)of BESS is always in the optimal operating range,and the total FR cost is the lowest at this time.The proposed method can achieve the optimal balance between ACE reduction and operational economy of BESS.The effectiveness of the proposed strategy is verified in a two-area power system.展开更多
This work studies the constrained optimal execution problem with a random market depth in the limit order market.Motivated from the real trading activities,our execution model considers the execution bounds and allows...This work studies the constrained optimal execution problem with a random market depth in the limit order market.Motivated from the real trading activities,our execution model considers the execution bounds and allows the random market depth to be statistically correlated in different periods.Usually,it is difficult to achieve the analytical solution for this class of constrained dynamic decision problem.Thanks to the special structure of this model,by applying the proposed state separation theorem and dynamic programming,we successfully obtain the analytical execution policy.The revealed policy is of feedback nature.Examples are provided to illustrate our solution methods.Simulation results demonstrate the advantages of our model comparing with the classical execution policy.展开更多
An accurate and wide-angle one-way propagator for wavefield extrapolation is an important topic for research on wave-equation prestack depth migration in the presence of large and rapid velocity variations. Based on t...An accurate and wide-angle one-way propagator for wavefield extrapolation is an important topic for research on wave-equation prestack depth migration in the presence of large and rapid velocity variations. Based on the optimal separable approximation presented in this paper, the mixed domain algorithm with forward and inverse Fourier transforms is used to construct the 3D one-way wavefield extrapolation operator. This operator separates variables in the wavenumber and spatial domains. The phase shift operation is implemented in the wavenumber domain while the time delay for lateral velocity variation is corrected in the spatial domain. The impulse responses of the one-way wave operator show that the numeric computation is consistent with the theoretical value for each velocity, revealing that the operator constructed with the optimal separable approximation can be applied to lateral velocity variations for the case of small steps. Imaging results of the SEG/EAGE model and field data indicate that the new method can be used to image complex structure.展开更多
针对传统的基于Delaunay三角网的逐点内插算法难以同时兼顾精度和效率的问题,依据Voronoi单胞和Delaunay三角形的几何特性,提出了一种基于局部动态最优Delaunay三角网的逐点内插算法,并在格网数字水深模型(grid digital depth model,Gri...针对传统的基于Delaunay三角网的逐点内插算法难以同时兼顾精度和效率的问题,依据Voronoi单胞和Delaunay三角形的几何特性,提出了一种基于局部动态最优Delaunay三角网的逐点内插算法,并在格网数字水深模型(grid digital depth model,Grid-DDM)中进行应用。实验结果表明,该改进算法能保证插值精度并明显提高执行效率。展开更多
文摘A series of single hole blasting crater experiments and a variable distance multi-hole simultaneous blasting experiment was carried in the Yunfu Troilite Mine,according to the Livingston blasting crater theory.We introduce in detail,our methodology of data collection and processing from our experiments.Based on the burying depth of the explosives,the blasting crater volume was fitted by the method of least squares and the characteristic curve of the blasting crater was obtained using the MATLAB soft- ware.From this third degree polynomial,we have derived the optimal burying depth,the critical burying depth and the optimal explosive specific charge of the blasting crater.
基金This work was supported by Open Research Project of State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments,Tsinghua University(No.SKLD20M20)Xinjiang Uygur Autonomous Region Natural Science Key Project of University Research Program(No.XJEDU2020I004).
文摘Battery energy storage systems(BESSs)can provide instantaneous support for frequency regulation(FR)because of their fast response characteristics.However,purely pursuing a better FR effect calls for continually rapid cycles of BESSs,which shortens their lifetime and deteriorates the operational economy.To coordinate the lifespan savings and the FR effect,this paper presents a control strategy for the FR of BESSs based on fuzzy logic and hierarchical controllers.The fuzzy logic controller improves the effect of FR by adjusting the charging/discharging power of the BESS with a higher response speed and precision based on the area control error(ACE)signal and the change rate of ACE in a non-linear way.Hierarchical controllers effectively reduce the life loss by optimizing the depth of discharge,which ensures that the state of charge(SOC)of BESS is always in the optimal operating range,and the total FR cost is the lowest at this time.The proposed method can achieve the optimal balance between ACE reduction and operational economy of BESS.The effectiveness of the proposed strategy is verified in a two-area power system.
基金This research is partially supported by the National Natural Science Foundation of China(No.61573244).
文摘This work studies the constrained optimal execution problem with a random market depth in the limit order market.Motivated from the real trading activities,our execution model considers the execution bounds and allows the random market depth to be statistically correlated in different periods.Usually,it is difficult to achieve the analytical solution for this class of constrained dynamic decision problem.Thanks to the special structure of this model,by applying the proposed state separation theorem and dynamic programming,we successfully obtain the analytical execution policy.The revealed policy is of feedback nature.Examples are provided to illustrate our solution methods.Simulation results demonstrate the advantages of our model comparing with the classical execution policy.
基金This research is sponsored by China National Natural Science Foundation （N0. 40474047）.
文摘An accurate and wide-angle one-way propagator for wavefield extrapolation is an important topic for research on wave-equation prestack depth migration in the presence of large and rapid velocity variations. Based on the optimal separable approximation presented in this paper, the mixed domain algorithm with forward and inverse Fourier transforms is used to construct the 3D one-way wavefield extrapolation operator. This operator separates variables in the wavenumber and spatial domains. The phase shift operation is implemented in the wavenumber domain while the time delay for lateral velocity variation is corrected in the spatial domain. The impulse responses of the one-way wave operator show that the numeric computation is consistent with the theoretical value for each velocity, revealing that the operator constructed with the optimal separable approximation can be applied to lateral velocity variations for the case of small steps. Imaging results of the SEG/EAGE model and field data indicate that the new method can be used to image complex structure.
文摘针对传统的基于Delaunay三角网的逐点内插算法难以同时兼顾精度和效率的问题,依据Voronoi单胞和Delaunay三角形的几何特性,提出了一种基于局部动态最优Delaunay三角网的逐点内插算法,并在格网数字水深模型(grid digital depth model,Grid-DDM)中进行应用。实验结果表明,该改进算法能保证插值精度并明显提高执行效率。
