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Dual-color two-photon excitation (TPE)-fluorescence imaging is used in conventional TFMPEM to observe specimens with different fluorophore labels. However, concerns have been raised about the excitation efficiency and selectivity of the fluorophores under fixed-wavelength excitation. This study presents a wavelength-switching approach using a scanning mirror, beam expander, and diffraction grating in the TFMPEM to switch the excitation wavelengths and match the optimal absorption of the fluorophores to acquire dynamic dual-color TPE-fluorescence images. The presented TFMPEM system was demonstrated to have an axial excitation confinement of 2.3–5.0 μm for excitation wavelengths of 730–1000 nm, and was used to visualize three-dimensional images of the vasculature of a mouse brain. The TPE efficiencies of different fluorophores were evaluated through TFMPEM imaging with excitation wavelength scanning to obtain their TPE spectra. Consequently, time-lapsed dual-color TFMPEM imaging was performed on rhodamine 6G (R6G)–poly(lactic-co-glycolic acid) (PLGA) nanoparticles and enhanced-yellow-fluorescent protein (EYFP)-tagged clathrin using excitation wavelengths at the maximum TPEs of R6G and EYFP, respectively. Our results revealed the PLGA-nanoparticle uptake of live cells via long-lived clathrin-coated plaques in clathrin-mediated endocytosis.

In civil engineering, the nonlinear dynamic instability of structures occurs at a bifurcation point or a limit point. The instability at a bifurcation point can be analyzed with the theory of nonlinear dynamics, and that at a limit point can be discussed with the theory of elastoplasticity. In this paper, the nonlinear dynamic instability of structures was treated with mathematical and mechanical theories. The research methods for the problems of structural nonlinear dynamic stability were discussed first, and then the criterion of stability or instability of structures, the method to obtain the bifurcation point and the limit point, and the formulae of the directions of the branch solutions at a bifurcation point were elucidated. These methods can be applied to the problems of nonlinear dynamic instability of structures such as reticulated shells, space grid structures, and so on.

The conventional signal reconstruction problem of multirate systems with channel noises can be cast as a robust multirate deconvolution design problem. We investigate a unified minimax approach for the robust deconvolution design of multirate systems. We discuss two typical multirate systems: the multirate filter bank system and the transmultiplexer system. We consider transmission noises resulting from quantization coding errors or external noises. The deconvolution filters for these systems that we derive are all IIR filters. The keypoint is converting the original robust deconvolution design problem to an equivalent minimax matching problem via polyphase decomposition and noble identities. Then, in spite of the presence of input signals and channel noises, we can solve this minimax matching problem by an optimization technique. The proposed method can be interpreted as designing an optimal multirate deconvolution filter such that the worst-case multirate system reconstruction error is minimized over all possible inputs and noises from the energy perspective. Therefore, our proposed design method is more robust than the conventional design method for multirate systems in the presence of uncertain input signals and channel noises. We present several numerical examples that show the good performance of our design method.

A robust H/sup /spl infin// optimal design problem under a structure-specified controller is investigated for systems with parameter variations and disturbance uncertainties. A simple and facile design algorithm is proposed to solve the structure-specified H/sup /spl infin// optimization problem via genetic searching approach from suboptimal perspective. The proposed design method is very suitable for practical control systems. Therefore, the gap between the theoretical H/sup /spl infin// control and practical engineering designs can be filled up. Two examples involving a single input-single output (SISO) phase-locked-loop motor speed system with a lead/lag type controller and an MIMO supermaneuverable F18/HARV fighter aircraft system with a PID-type controller are given to illustrate the design procedure and exhibit the performance of the proposed method.

This work solves the signal reconstruction problem involving nonuniform filter bank systems with rational decimation factors and noise. Three main nonuniform filter bank systems, i.e., filter-block decimator (FBD) structure, upsampler-filter-downsampler (UFD) structure, and tree structure, are included in this study. According to different operating conditions, two different signal reconstruction problems for nonuniform filter bank systems with noise under the unknown but identifiable input signal model and the unknown input signal model are discussed, respectively. At the first stage, a unified block state space model for different nonuniform filter bank systems with noise is developed. Then, by incorporating the identified input signal model with this unified state space model and appropriate choice of the augmented state vector, the signal reconstruction problem is reduced to an equivalent state estimation problem for resulting augmented systems if the input signal is identifiable. If the input signal is lacking in modeling, the signal reconstruction is discussed from the minimax estimation point of view. Two state estimation techniques involving robust Kalman filtering and H/sub /spl infin// filtering are employed, respectively, to treat the signal reconstruction problem of nonuniform filter bank systems according to different a priori knowledge of the input signal. Finally, several numerical examples are presented to illustrate the proposed algorithms and exhibit the performances.

Over the past two years, the construction industry has increasingly recognized the benefits and capabilities of building information modeling (BIM) for information integration, visualization and parametric design, reducing the duplication of work and complexity of interface integration, while significantly saving both time and cost. However, due to the variety of participants in engineering projects, the differences between data definition, data format, and data storage increase the difficulty of integrating data from diverse sources. Therefore, buildingSMART has developed a common data schema, called Industry Foundation Classes (IFC), that makes it possible to hold and exchange relevant data between different software applications, to increase the efficiency of BIM work and to ensure a consistent and high-quality output. This paper presents a novel methodology that assists in facilitating the import and export process for parametric BIM objects between heterogeneous BIM systems. This methodology is based on the IFC data schema and includes graphical and non-graphical description data. The objective is to retain the geometry, parameters, unit, texture and links of an object during exchange and sharing to ensure that data integrity is maintained. To sum up, this research addresses the issues of transferring parametric BIM objects between heterogeneous systems to increase data integrity and reduce transfer and integration times.

Mixed H/sub 2//H/sub /spl infin// control designs are quite useful for robust performance design for systems under parameter perturbation and uncertain disturbance. However, the conventional output feedback designs of mixed H/sub 2//H/sub /spl infin// optimal control are very complicated and not easily implemented for practical industrial applications. In this article, a PID design algorithm for mixed H/sub 2//H/sub /spl infin// control is proposed via the technique of genetic searching algorithms. Genetic algorithms are optimization and machine learning algorithms, initially inspired from the processes of natural selection and evolutionary genetics. The proposed design algorithm will bridge the gap between the theoretical mixed H/sub 2//H/sub /spl infin// optimal control and classical PID industrial controls. Two design examples are given to illustrate the design procedure and the performance of the proposed algorithm. >

In this paper, we propose an enhancement partition method that incorporates formal partition, fitting system constraints and hardware orient partition algorithm to solve partitioning issue for embedded multiprocessor FPGA systems. With formal partition, we can rapidly obtain a set of partitioning results that satisfy the system constraints on the number of processors. To fit various system constraints, we find out all partition result sets by fitting system constraints. Finally, hardware orient partition can provide a nearly best partition result for designer to develop multiprocessors system-on-a-chip system. Experiment results show that the proposed method can obtain the fitting best partitioning result than other partitioning method using JPEG encoding system example.

In this paper, we present hardware-oriented partitioning approach that can solve the partitioning issues for embedded multiprocessor FPGA systems. In addition, it can gain a better partitioning result, faster execution time, less memory and higher slice used rate, under satisfied system constraints. We also demonstrate the feasibility of our approach by a JPEG encoding system using Xilinx ML310 FPGA platform. Experiment results show that the execution time and memory size are improved.

Background: Haglund syndrome is a cause of posterior heel pain. The prominent posterosuperior projection into the retrocalcaneal bursa is thought to be a major etiology. Many methods have been proposed to measure the posterosuperior projection of the tuberosity into this bursa. The Fowler angle and the parallel pitch lines are the most frequently used. However, the relation between symptomatic Haglund syndrome and the measuring methods, especially the Fowler angle and parallel pitch lines, is not clear. The purposes of this paper were to study the predictive value of the most frequently used measurement methods to evaluate bursal impingement and to determine if other osseous variations and Achilles tendon calcification are associated with the development of Haglund syndrome. Methods: From October, 1996, to March, 2003, we evaluated 37 heels in 31 patients with symptomatic Haglund syndrome, and 40 heels in 27 individuals without posterior heel pain. On a lateral view radiograph, the Fowler angle, and the parallel pitch lines were measured, in addition to Achilles tendon calcification and the osseous variations, such as a posterior calcaneal step spur or plantar osseous projection. Results: The average Fowler angles in the control group and study group were 62.31 ± 7.79 degrees and 60.14 ± 7.01 degrees, respectively. There was no statistically significant difference ( p = 0.490). The positive parallel pitch lines in the symptomatic group were 56.8% and in the control group 42.5%. There was no statistically significant difference ( p = 0.474) between the groups. Conclusions: No statistically significant differences were noted between the groups concerning the Fowler angle and parallel pitch lines. The posterior calcaneal step spur and Achilles tendon calcification were statistically significant between these two groups. The Fowler angle and parallel pitch lines were of little predictive value for the Haglund syndrome.

An application of wavelet networks to control problems of nonlinear systems is investigated in this paper. A wavelet network is constructed as an alternative to a neural network to approximate a nonlinear system. Based on this wavelet network approximation, suitable adaptive control laws and appropriate parameter update algorithms for nonlinear uncertain (or unknown) systems are derived to achieve H/sub /spl infin// tracking performance. It is shown that the effects of approximation errors and external disturbances can be attenuated to a specific attenuation level by the proposed adaptive wavelet network control scheme.

Publisher Summary Fuzzy control has recently found extensive application for a wide variety of industrial systems and consumer products and has attracted the attention of many control researchers because of its model free approach. This chapter describes the Fuzzy logic systems, H∞ tracking performance designs in both indirect and direct adaptive fuzzy systems, and provides two simulation examples to illustrate the performance of the proposed methods. The H∞ control technique is combined with an adaptive control algorithm and a fuzzy approximation method in this study to achieve the desired attenuation of disturbance because of the approximation error and external noise in a class of nonlinear system under a large uncertainty or unknown variation in plant parameter and structure. Both indirect and direct adaptive fuzzy control algorithms have been employed to treat this H∞ tracking design problem. The solvability conditions and the corresponding adaptive fuzzy control laws are both derived. The results indicate that an arbitrarily small attenuation level can be achieved, if the magnitude of weighting factor r can be chosen to be as small as possible. Simulation results confirm that the H∞ tracking performance can be achieved via the proposed adaptive fuzzy control algorithms. However, further works are still required to apply the proposed adaptive fuzzy H∞ tracking algorithm to the more general nonlinear systems.

The principal accuracy limitation of a hydrogen maser is the uncertainty in the determination of the hydrogen maser wail shift. In this paper, we describe in detail the experiments on hydrogen maser wall shift and introduce briefly works on hydrogen masers in the Shanghai Bureau of Metrology. In experiments, we changed five different size storage bulbs by. turns. These bulbs were all coated in the same way with a locally made F4 coating. Results of the experiments are K(40°C) = -293 ± 17 mHzcm and a(40°C) = (-17 ± 2) × 10-30C-1. The unperturbed hyperfine frequency of the ground state of the hydrogen atomf0-0 was obtained by comparing five hydrogen masers to Loran C navigation system signals for one month. The average value in respect to TAI isf0-0 = 1420 405 751.768 ± 0.002 Hz. This value is closely in agreement with values of f0-0, which have been published by other authors since 1970.