Design of interval type-2 fuzzy sliding-mode controller

In this paper, an interval type-2 fuzzy sliding-mode controller (IT2FSMC) is proposed for linear and nonlinear systems. The proposed IT2FSMC is a combination of the interval type-2 fuzzy logic control (IT2FLC) and the sliding-mode control (SMC) which inherits the benefits of these two methods. The objective of the controller is to allow the system to move to the sliding surface and remain in on it so as to ensure the asymptotic stability of the closed-loop system. The Lyapunov stability method is adopted to verify the stability of the interval type-2 fuzzy sliding-mode controller system. The design procedure of the IT2FSMC is explored in detail. A typical second order linear interval system with 50% parameter variations, an inverted pendulum with variation of pole characteristics, and a Duffing forced oscillation with uncertainty and disturbance are adopted to illustrate the validity of the proposed method. The simulation results show that the IT2FSMC achieves the best tracking performance in comparison with the type-1 Fuzzy logic controller (T1FLC), the IT2FLC, and the type-1 fuzzy sliding-mode controller (T1FSMC).     

Constructing a 3-D mesh model for electrical cardiac activity simulation.

The 3-D ventricle model in this study was reconstructed from a series of MRI torso cross-section data. We used a 3-D voxel array to represent the ventricle. As in cardiac simulations proposed by previous studies, the activation sequence and body surface ECG were simulated in this model. But to reduce the amount of elements in the model, so that the amount of parameters in the model can be handled numerically, we propose another approach to simulate cardiac activity. A mesh model was constructed on the closed surface formed by epicardiac and endocardiac surfaces of the ventricle. We propose a method to simulate the activation sequence on the epicardiac and endocardiac surfaces of the mesh model. As with the uniform double layer theorem, body surface ECG can be estimated in terms of epicardiac and endocardiac surface current source. Consequently, we can also generate ECG waveforms corresponding to this mesh simulation. Both the depolarization sequence and ECG simulated by the mesh model resemble those generated by the 3-D voxel model. However, the mesh model greatly simplified the process of ECG simulation. Both the simulation of depolarization and ECG estimation were expressed in terms of clear and simple mathematical representations. Consequently, we can analytically investigate the effects of the mesh model's parameters on the cardiac activation sequence and ECG. It could be a useful tool to numerically study the relation of ECG waveforms and electrical activity of the heart.     

Synthesis and properties of copolypyromellitimides

Copolyamic acids with different proportions of diamine component were prepared by polymerizing different molar ratios of diamines—benzidine (B)/4,4′-diaminodiphenyl ether (E) and p-phenylene diamine (P)/4,4′-diaminodiphenyl methane (M)—with pyromellitic dianhydride (PMDA) in dimethylacetamide (DMAc) at room temperature. Diamine component can be arranged in regular sequence through various reaction processes, such as alternating, block, and partial block copolymers. In addition, it can also be arranged in random sequence to obtain random copolymers. Thermal cyclodehydration of polyamic acids results in the corresponding polyimides. Polymers are characterized by viscosity, thermal stability, crystallinity, and mechanical strength. It was found that an increase in the proportion of more flexible diamine component (such as E and M) incorporated in polymer chain results in copolyimides with better mechanical strength and causes a fall in viscosity of copolyamic acids and a decrease in thermal stability and crystallinity of copolyimides. Within the copolymers of the same composition, the thermal stability, crystallinity, and mechanical strength of ordered polymers are superior to those of random polymers. The results of viscosity measurements imply that the anhydride-terminated prepolymer is easily destroyed by water in the solution, so that the ultimate viscosities of alternating and block copolyamic acids are inferior to those of random ones, but this phenomenon can be improved through the preparation of the partial block copolymers.     

How did national life expectation related to school years in developing countries—An approach using panel data mining

Background

The purpose of the study was to probe into the changes in life expectancy associated with schooling years found by the Organization for Economic Co-operation and Development (OECD).

Methods

The study was based on the OECD database from the period 2000 to 2006. The data of thirty countries were constructed to allow comparisons over time and across these countries. Panel data analysis was used to estimate the relationship of national education, as defined as school years, with life expectancy. The control factors considered were numbers of practicing physicians, practicing nurses, hospital beds, and GDP.

Results

We used fixed effects of both country and time through linear regression, the coefficient of school years in relation to life expectancy was statistically significant but negative. This finding is not in accord with the hypothesis that investing in human capital through education stimulates better health outcomes.

Conclusion

Within developing countries, educational attainment is no longer keeping the same pace with life expectancy as before. Therefore, we suggest that an effective education policy should cover diverse topics, for example, balancing economic growth and mental hygiene, to improve national life expectancy.     

Size effect on mechanical properties of TiO2 capped nanotubes investigated using in situ transmission electron microscopy

In situ transmission electron microscopy nanoindentation tests are used to measure the compressive fracture and mechanical properties of individual titanium oxide (TiO₂) capped nanotubes. The average critical loads ranged from 3.6 to 9.6 μN. Individual TiO₂ capped nanotubes with lengths of 8–10 μm were found to have Young’s modulus values of ~2.2–9.4 GPa and work energy values of ~3.1–6.6 × 10^?13 J. The results indicate that the Young’s modulus and tensile strength depend on capped nanotube length.     

A hybrid approach of dimension partition and velocity control to enhance performance of particle swarm optimization

Particle swarm optimization (PSO) is a population-based optimization technique and it has been used to solve many optimization problems successfully. However, more efficient strategies are still needed to control the trade-off between exploitation exploration in the search process for solving tasks with high complexity. In this work, we present a new hybrid PSO approach to overcome the search difficulties. Our approach focuses on two search strategies. One is a two-swarm cooperative strategy that controls search region and integrates full and single dimension PSO search. The other strategy is to control the velocity of the particles in an adaptive way, according to how they move in the space. To evaluate the performance and generality of our hybrid approach, extensive experiments have been conducted and the results confirm the effectiveness of the proposed approach.     

4 x 4 vertical-cavity surface-emitting laser (VCSEL) and metal-semiconductor-metal (MSM) optical backplane demonstrator system

We describe a system demonstrator based on vertical-cavity surface-emitting lasers, metal-semiconductor-metal detectors, printed circuit board (PCB) level optoelectronic device packaging, a compact bulk optical relay, and novel barrel/PCB optomechanics. The entire system was constructed in a standard VME electrical backplane chassis and was capable of operating at >1.7 Gbit/s of aggregate data capacity. In addition to the component technologies developed, we describe operational testing and characterization of the demonstrator.     

Real-time triple product relighting using spherical local-frame parameterization

This paper addresses the problem of real-time rendering for objects with complex materials under varying all-frequency illumination and changing view. Our approach extends the triple product algorithm by using local-frame parameterization, spherical wavelets, per-pixel shading and visibility textures. Storing BRDFs with local-frame parameterization allows us to handle complex BRDFs and incorporate bump mapping more easily. In addition, it greatly reduces the data size compared to storing BRDFs with respect to the global frame. The use of spherical wavelets avoids uneven sampling and energy normalization of cubical parameterization. Finally, we use per-pixel shading and visibility textures to remove the need for fine tessellations of meshes and shift most computation from vertex shaders to more powerful pixel shaders. The resulting system can render scenes with realistic shadow effects, complex BRDFs, bump mapping and spatially-varying BRDFs under varying complex illumination and changing view at real-time frame rates on modern graphics hardware.     

Parallel scrambler for high-speed applications

In order to improve the speed limitation of serial scrambler, we propose a new parallel scrambler architecture and circuit to overcome the limitation of serial scrambler. A very systematic parallel scrambler design methodology is first proposed. The critical path delay is only one D-register and one xor gate of two inputs. Thus, it is superior to other proposed circuits in high-speed applications. A new DET D-register with embedded xor operation is used as a basic circuit block of the parallel scrambler. Measurement results show the proposed parallel scrambler can operate in 40 Gbps with 16 outputs in TSMC 0.18-/spl mu/m CMOS process.     

The design and analysis of a DLL-based frequency synthesizer for UWB application

A delay-locked loop (DLL)-based frequency synthesizer is designed for the ultrawideband (UWB) Mode-1 system. This frequency synthesizer with 528-MHz input reference frequency achieves less than 9.5-ns settling time by utilizing wide loop bandwidth and fast-settling architecture. Additionally, a discrete-time model of the DLL and an analytical model of phase noise of the delay line are proposed in this work. Experimental results show great consistency with predicted settling time and phase noise. The circuit has been fabricated in a 0.18-/spl mu/m CMOS technology and consumes only 54 mW from a 1.8-V supply. It exhibits a sideband magnitude of -35.4 dBc and -120-dBc/Hz phase noise at the frequency offset of 1 MHz.