检索结果-南通市图书馆

A new heuristic algorithm for the circular packing problem with equilibrium constraints

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(information sciences) 2011年第8期54卷 1572-1584页

作者： LIU JingFa 1,2,LI Gang 3 & GENG HuanTong 1 1 school of Computer and Software,nanjing university of information science & technology,nanjing 210044,china 2 Network information Center,nanjing university of information science & technology, nanjing 210044,china 3 school of mathematics and physics,nanjing university of information science & technology,nanjing 210044,china 1. school of Computer and Software Nanjing University of Information Science & Technology Nanjing 210044 China2. Network Information Center Nanjing University of Information Science & Technology Nanjing 210044 China3. School of Mathematics and Physics Nanjing University of Information Science & Technology Nanjing 210044 China

The circular packing problem with equilibrium constraints is an optimization problem about simplified satellite module layout design.A heuristic algorithm based on tabu search is put forward for solving this *** algorithm begins from a random initial configuration and applies the gradient method with an adaptive step length to search for the minimum energy *** jump out of the local minima and avoid the search doing repeated work,the algorithm adopts the strategy of tabu *** the process of tabu search,we improve the traditional neighboring solutions,tabu objects and the acceptance criteria of the current solution *** test two sets of benchmarks consisting of 11 representative instances from the current *** numerical results show that the proposed algorithm breaks the records in seven out of 11 instances,and obtains the optimal solutions for the other four instances.

关键词： equilibrium constraints packing problem heuristic algorithm tabu search layout optimization

Research into a theoretical mode of coherent structures in the wall region of a turbulent boundary layer induced by a wall local disturbance

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2009年第9期19卷 1119-1124页

作者： Changgen Lua,*, Qinjuan Qi b a College of Atmospheric sciences, nanjing university of information science & technology, nanjing 210044, china b College of Public Management, nanjing university of information science & technology, nanjing 210044, china [a]College of Atmospheric sciences Nanjing University of Information Science & Technology Nanjing 210044 China [b]College of Public Management Nanjing University of Information Science & Technology Nanjing 210044 China

The idea of applying direct numerical simulation (DNS), a theoretical mode of coherent structures in the wall region of a turbulent boundary layer, has been discussed in the literature. The various aspects of the formation mechanism of the coherent structures agree well with both DNS and experimental results. In addition, a close relationship has been found between the evolutional characteristics and factors such as the magnitude and structural distribution of the wall local impulse disturbance, and the amount of energy a local disturbance introduces into the wall region. Moreover, these parameters play key roles in the formation of coherent structures near the wall region of a turbulent boundary layer. Therefore, the wall local impulse disturbance provides a theoretical model for triggering the formation of coherent structures in the wall region of a turbulent boundary layer.

关键词： Turbulent boundary layer Wall region Coherent structure Local disturbance

A Note on the Completeness of an Exponential Type Sequence

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 2011年第4期32卷 527-532页

作者： Jinhui FANG Department of mathematics Nanjing University of Information Science and Technology Nanjing 210044 China

For any given coprime integers p and q greater than 1, in 1959, B proved that all sufficiently large integers can be expressed as a sum of pairwise terms of the form p^aq^b. As Davenport observed, Birch＇s proof can be modified that the exponent b can be bounded in terms of p and q. In 2000, N. Hegyvari effective version of this bound. The author improves this bound.

关键词： Complete sequence Coprime Residue J. Birch distinct to show gave an

Resolution method for overlapping peaks based on the fractional-order differential

在线全文

学校读者我要写书评

暂无评论

science china Chemistry 2007年第6期50卷 797-805页

作者： LI YuanLu1, YU ShengLin2 & ZHENG Gang2 1 College of information & Control, nanjing university of information science & technology, nanjing 210044, china 2 College of Automation Engineering, nanjing university of Aeronautics and Astronautics, nanjing 210016, china 1. College of information & Control Nanjing University of Information Science & Technology Nanjing 210044 China 2. College of Automation Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

Equations between the differential order and the maximum of the fractional-order differential for the specified peak signals are developed based on the variation of the maximum of the specified peak signals at different orders. Also, equations between the differential order and the zero-crossing of the fractional-order differential of the specified peak signals are proposed according to the variation of the zero-crossing of the specified peak signals at different orders. Characteristic paramters of the Gaus- sian peak, Lorentzian peak, and Tsallis peak can be estimated using estimator I and estimator II which are obtained by the equations above. As a result, a new method is presented to resolve the overlapped peaks signal. Firstly, a fractional-order differential of the specified peak signals is obtained with the fractional-order differentiation filter. Then, characteristic paramters of the specified peak signals can be extracted using estimator I and estimator II. Finally, the Tsallis peak is used as a model to assign the overlapping peak signals correctly. Experimental results show that the proposed method is efficient and effective for the simulated overlapping peaks and detected overlapping voltammetric peak signals.

关键词： fractional-order differentiation filter, fractional-order differential, overlapping peaks, voltammetric peak

Selection of unitary operations in quantum secret sharing without entanglement

在线全文

学校读者我要写书评

暂无评论

science china(information sciences) 2011年第9期54卷 1837-1842页

作者： XU Juan 1,CHEN HanWu 1,LIU WenJie 1,2 & LIU ZhiHao 1 1 school of Computer science and Engineering,Southeast university,nanjing 210096,china 2 school of Computer and Software,nanjing university of information science and technology,nanjing 210044,china 1. school of Computer science and Engineering Southeast University Nanjing 210096 China2. School of Computer and Software Nanjing University of Information Science and Technology Nanjing 210044 China

We propose a substitute-Bell-state attack strategy for quantum secret sharing schemes without entanglement,as well as a definition of the minimum failure probability of such attack strategy.A quantitative analysis of security degrees corresponding to different unitary operations is also provided,when the secret sharing schemes without entanglement are stricken by substitute-Bell-state *** a result,the relation between the selection of unitary operations and the effect of substitute-Bell-state attack is shown,which can serve as an important guidance for the selection of unitary operations in designing and implementing quantum secret sharing schemes.

关键词： quantum secret sharing substitute-Bell-state attack unitary operation minimum failure probability

A relative local variational principle for topological pressure

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china mathematics 2010年第6期53卷 1491-1506页

作者： MA XianFeng1,CHEN ErCai2,3,& ZHANG AiHua2,4 1Department of mathematics,East china university of science and technology,Shanghai 200237,china 2school of mathematics and Computer science,nanjing Normal university,nanjing 210097,china 3Center of Nonlinear science,nanjing university,nanjing 210093,china 4College of mathematics and physics,nanjing university of Posts and Telecommunications,nanjing 210046,china 1. Department of mathematics East China University of Science and Technology Shanghai 200237 China2. School of Mathematics and Computer Science Nanjing Normal University Nanjing 210097 China3. Center of Nonlinear Science Nanjing University Nanjing 210093 China4. College of Mathematics and Physics Nanjing University of Posts and Telecommunications Nanjing 210046 China

We define the relative local topological pressure for any given factor map and open cover,and prove the relative local variational principle of this *** precisely,for a given factor map π:(X,T)→(Y,S) between two topological dynamical systems,an open cover U of X,a continuous,real-valued function f on X and an S-invariant measure ν on Y,we show that the corresponding relative local pressure P(T,f,U,y) satisfies sup μ∈M(X,T){ hμ(T,U|Y)+∫X f(x)dμ(x) :πμ=ν}=∫Y P(T,f,U,y)dν(y),where M(X,T) denotes the family of all T-invariant measures on ***,the supremum can be attained by a T-invariant measure.

关键词： pressure conditional entropy relative local variational principle

Tsallis model-based separation of overlapped peak signals

在线全文

学校读者我要写书评

暂无评论

science china(information sciences) 2010年第4期53卷 823-832页

作者： LI YuanLu*, ZHANG YingChao & TANG HuiQiang College of information and Control, nanjing university of information science & technology, nanjing 210044, china 1. College of information and Control Nanjing University of Information Science & Technology Nanjing 210044 China

A simple scheme for separating overlapped peak signals (OPS) is proposed, with the Tsallis distribution as the model for OPS processing and fractional-order differentiation as tool for the signal analysis, the relationships of the maxima and zero-crossing values of the Tsallis peak signal, separately, to the order of differentiation are established, leading to two types of parameter estimators, which are utilized, by adjusting the peak-shape parameter, to calculate the parameters of position, height and width of the Gaussian, Lorentzian and Tsallis distribution. The obtained characteristic parameters can be employed to fit the peak signals to be treated, thereby fulfilling the OPS decomposition.

关键词： fractional differentials filter overlapped peak signal Tsallis model separation of overlapped peak signals

Influence of mesoscale topography on vortex intensity

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2008年第1期18卷 71-78页

作者： Zhexian Luo*,Yun Gao Remote Sensing College,nanjing university of information science and technology,Najing 210044,china Remote Sensing College Nanjing University of Information Science and Technology Najing 210044 China

The effect of mesoscale topography on multi-vortex self-organization is investigated numerically in this paper using a barotropic prim- itive equation model with topographic *** the initial field there are one DeMaria major vortex with the maximum wind radius rm of 80 km at the center of the computational domain,and four meso-b vortices in the vicinity of rm to the east of the major vortex center. When there is no topography present,the initial vortices self-organize into a quasi-final state flow pattern,i.e.a quasi-axisymmetric vor- tex whose intensity is close to that of the initial major ***,when a mesoscale topography is incorporated,the spatial scale of the quasi-final state vortex reduces,and the relative vorticity at the center of the vortex and the local maximum wind speed remarkably *** possible mechanism for the enhancement of the quasi-final state vortex might be that the negative relative vorticity lump, generated above the mesoscale topography because of the constraint of absolute vorticity conservation,squeezes the center of positive vorticity towards the mountain slope area,and thus reduces the spatial range of the major ***,because the total kinetic energy is basically conservative,the squeezing directly leads to the concentration of the energy in a smaller area,*** strengthening of the vortex.

关键词： Mesoscale topography Vortex Self-organization Intensity change

A Raw Signal Simulator for Bistatic SAR

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2009年第4期22卷 434-443页

作者： Xia Weijie,Zhou Jianjiang College of information science and technology,nanjing university of Aeronautics and Astronautics,nanjing 210016,china [a]College of information science and technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

This article proposes a new efficient raw signal simulator for the bistatic synthetic aperture radar （SAR） based on 2D fast Fourier transform （FFT） to deal with cases of both ideal trajectory and trajectory deviation. It begins with analyzing the geometric configuration and the range history of the bistatic SAR in side-looking and squint modes of ideal trajectory as well as trajectory deviation. Then a detailed and mathematical study is conducted on the equivalence relation of bistatic-to-monostatic applications （BTMA） in the case of ideal trajectory and trajectory deviation. Also a set of formulas are derived for the equivalence relation between bistatic SAR and monostatic SAR on some reasonable assumptions. Therefore, the application of the simulation method based on the 2D FFT for the monostatic SAR can be extended to the case of bistatic SAR. Finally, the simulation results prove the validity of this method. By comparing the efficiency of the proposed method with that of the time domain method, it is shown that the former is a few orders of magnitude higher.

关键词： bistatic synthetic aperture radar raw signal simulation fast Fourier transform