THz-TDS signal analysis and substance identification via the conformal split

A terahertz time-domain spectroscopy(THz-TDS)imaging system can obtain high-dimensional signals with substance fingerprint information.By introducing geometric algebra,a novel signal analysis approach to THz-TDS signals is developed based on an optical physical mechanism.Using this approach,signals are represented with vectors in the high-dimensional real vector space.Geometric distribution properties and algebraic relationships of THz-TDS signals are deduced.It is proved that every complex refractive index of substances relates to a unique 2-blade,the vectors corresponding to the samples of the same substance are collinear and belong to the intrinsic 2-blade of the substance.When decomposed through the conformal split with respect to a 2-blade,THz-TDS signals of high dimensionality can be related to vectors in a 2-dimensional subspace.Based on the conformal split properties we deduced,two criteria for substance identification on the basis of THz-TDS signals are proposed.Accordingly,a novel substance identification method via the conformal split is presented.In the method,the 2-blade related to each "known" substance is calculated with two vectors corresponding to THz-TDS signals measured from samples of the substance but with dierent thicknesses.Using the conformal split with respect to those 2-blades,an identified vector corresponding to a THz-TDS signal is linearly related to the vector in a 2-dimensional subspace.The substance of a sample can be identified using criteria on the projected vectors in the subspaces.This method can contribute to accurate classification and identification.Finally,two experiments are presented that show the feasibility and accuracy of this method.     

Control allocation for a V/STOL aircraft based on robust fuzzy control

This study addresses the design of an output-feedback H-infinity and fuzzy mixed controller for an advanced vertical and/or short take-off and landing aircraft that exhibits satisfactory global stability criteria. A fuzzy logic based optimization approach is employed to solve autonomously the constrained control allocation problem by suitably adjusting the components of the output vector and finding a proper vector in the attainable moment set. Simulations show that the designed fuzzy controller is better s...     

Aeroservoelastic model based active control for large civil aircraft

A modeling and control approach for an advanced configured large civil aircraft with aeroservoelasticity via the LQG method and control allocation is presented.Mathematical models and implementation issues for the multi-input/multi-output(MIMO) aeroservoelastic system simulation developed for a flexible wing with multi control surfaces are described.A fuzzy logic based optimization approach is employed to solve the constrained control allocation problem via intelligently adjusting the components of output v...     

A constraint satisfaction neural network and heuristic combined approach for concurrent activities scheduling

Scheduling activities in concurrent product development process is of great sig-nificance to shorten developements lead time and minimize the cost.Moreover,it can eliminate the unnecessary redesign periods and guarantee that serial activities can be executed as concurrently as possible,This paper presents a constraint satisfaction neural network and heuristic combined approach for concurrent activities scheduling.In the combined approack,the neural network is used to obtain a feasible starting time of all the activities based on sequence constraints ,the heuristic algorithm is used to obtain a feasible solution of the scheduling problem based on resource constrainsts.The feasible scheduling solution is obtained by a gradient optimization function .Sim-ulations have shown that the proposed combined approach is efficient and fasible with respect to concurrent activities scheduling.     

Cooperative communications with hierarchical modulation in downlink OFDMA based cellular networks

Cooperative transmission is a promising way to improve system performance in orthogonal frequency division multiple access (OFDMA) based cellular networks.This paper proposes two heuristic cooperation ...     

Study on the vibration band gap and vibration attenuation property of phononic crystals

Phononic crystals (PCs) are functional materials with periodic structures and elastic wave (vibration) band gaps, where propagation of vibrations with frequencies within band gaps is forbidden. PCs with finite periods can restrain the propagation of vibrations with frequencies in band gaps and thus has vibration attenuation property. Worldwide, many institutions and researchers are engaged in the research of PCs, however, studies on the vibration attenuation property of PCs are still limited. In this paper, we report our study of band gaps and vibration attenuation properties of 1) a simplified PC—periodic mass-spring structures, 2) longitudinal vibration of one-dimensional (1D-), 2D-, 3D-PCs, and 3) the flexural vibration of 1D-and 2D-PCs. These studies provide a foundation for the applications of PCs in vibration attenuation. Supported by the 973 State Key Development Program for Basic Research of China (Grant No. 51307) Received September 27, 2005; accepted April 16, 2007     

全社会都要重视小城镇建设——江西省省长黄智权畅谈加快城镇化进程

日前,江西省全省农村工作会议在南昌召开,会议上江西省省长黄智权在对全面建设小康社会,加快全省城镇化建设时强调:全面建设小康社会的重点在农村,难点在农村,关键还在农村;没有农村的小康,就没有全省的小康。他吁请全省各部门乃至全社会都要关心、支持和重视小城镇建设。     

Electrochemically-tuned luminescence of a [Ru(bpy)2(tatp)]-sensitized TiO2 anode and its applications to photo-stimulated guanine/H2O2 fuel cells

A phenazine-containing Ru(II) complex [Ru(bpy)₂(tatp)]²⁺ (bpy = 2,2′-bipyridine and tatp = 1,4,8,9-tetra-aza-triphenylene) is first applied to a modification of the nano-TiO₂/indium-tin oxide (ITO) electrode by the method of repetitive voltammetric sweeping. The resulting [Ru(bpy)₂(tatp)]²⁺-modified TiO₂ electrode shows two pairs of well-defined redox waves and excellent electrocatalytic activity for the oxidation of guanine. [Ru(bpy)₂(tatp)]²⁺ on TiO₂ surfaces exhibits intense absorbance and photoluminescence in visible region, revealed by absorption spectra, emission spectra and fluorescence microscope. While [Ru(bpy)₂(tatp)]²⁺-sensitized TiO₂ is functionalized as an anode to combine with a continuous wave green laser via an optical microscope, the luminescence of Ru(II)-based excited states can be enhanced by the oxidation of guanine. Furthermore, the [Ru(bpy)₂(tatp)]²⁺-sensitized TiO₂ electrode is used as photoanode and hemoglobin-modified single-walled carbon nanotubes (SWCNTs) as cathode for the elaboration of a photo-stimulated guanine/H₂O₂ fuel cell with a saturated KCl salt-bridge. It becomes evident that the photo-stimulated fuel cell performance depends strongly on the excited states of Ru(II) complex-sensitized anodes as well as the electrocatalytic oxidation of guanine. This study provides an electrochemically-tuned luminescence method for better evaluating contributions of the sensitizer excited states to photo-stimulated fuel cells.     

Structural topology optimization: Extensibility and attainability

Extensibility and attainability of topology optimization are discussed by investigating a variety of simultaneous topology opti-mization methods extended from the standard formulation. First, the state of the art is highlighted through systematic classification of developed methods, such as simultaneous topology optimizations of microstructure and macrostructure, structure and supports, structure and design-dependent loads, structure and locations of involved components. Second, some recent results about simultaneous topology optimization of structure and applied loads are presented. It is shown that the simultaneous topology optimization is an integrated methodology that extends the concept of standard topology optimization in the sense of systematic design. The presence of more than one kind of design variable of different nature makes the optimization problem complex but enlarges the design space to attain the optimization.     

A Constraint Satisfaction Neural Network and Heuristic Combined Approach for Concurrent Activities Scheduling

Scheduling activities in concurrent product development process is of great significance to shorten development lead time and minimize the cost. Moreover, it can eliminate the unnecessary redesign periods and guarantee that serial activities can be executed as concurrently as possible. This paper presents a constraint satisfaction neural network and heuristic combined approach for concurrent activities scheduling. In the combined approach, the neural network is used to obtain a feasible starting time of all the activities based on sequence constraints, the heuristic algorithm is used to obtain a feasible solution of the scheduling problem based on resource constraints. The feasible scheduling solution is obtained by a gradient optimization function. Simulations have shown that the proposed combined approach is efficient and feasible with respect to concurrent activities scheduling.