Narrow Results

We address the problem of reducing the size of (nondeterministic, bottom-up) tree automata (TA) using suitable, language-preserving equivalences on the states of the automata. In particular, we propose the so-called composed bisimulation equivalence as a new language preserving equivalence. A composed bisimulation equivalence is defined in terms of two different relations, namely the upward and downward bisimulation equivalence. We provide simple and efficient algorithms for computing these relations. The notion of composed bisimulation equivalence is motivated by an attempt to obtain an equivalence that can provide better reductions than what currently known bisimulation-based approaches can offer, but which is not significantly more difficult to compute (and hence stays below the computational requirements of simulation-based reductions). The experimental results we present in the paper show that our composed bisimulation equivalence meets such requirements, and hence provides users of TA with a finer way to resolve the trade-off between the available degree of reduction and its cost.

The excessive computational resources required by the Nearest Neighbor rule are a major concern for a number of specialists and practitioners in the Pattern Recognition community. Many proposals for decreasing this computational burden, through reduction of the training sample size, have been published. This paper introduces an algorithm to reduce the training sample size while preserving the original decision boundaries as much as possible. Consequently, the algorithm tends to obtain classification accuracy close to that of the whole training sample. Several experimental results demonstrate the effectiveness of this method when compared to other reduction algorithms based on similar ideas.

Microstrip Wilkinson power dividers with harmonic suppression and size reduction are investigated. It is found that by loading reactive components at the middle of high impedance transmission lines (TLs), both size reduction and harmonic suppression can be achieved. Analyses and designs of such a kind of power divider are formulated in this paper. To demonstrate the design methodology, two power dividers centered at 1.8 GHz are optimally designed and confirmed by experiments. As compared with conventional Wilkinson power divider, the proposed power divider exhibits 55.6% size reduction, and high suppressions are achieved for 2nd and 3rd harmonic components. Both simulations and measurements are presented with good agreement.

Fabrication of structures on the micro- and nanometer scales is of great importance for both fundamental research and potential applications. While microlithography methods are relatively established, the production of multi-component micro- and nanostructures with high density still presents difficulties. In this paper, a novel strategy termed as two-dimensional (2D) stepwise contraction and adsorption nanolithography (SCAN) is used to fabricate true-color micropatterns through a series of size-reduction process based on the physical elasticity of elastomer. Faithful multicolor patterns with feature size about 30 times smaller than the initial ones can be fabricated by employing the 2D SCAN. The simplicity and high throughput capability of SCAN make it a competitive alternative to other micro- and nanolithography techniques.

A highly efficient method for size reduction of nanoparticles has been reported. Ferroelectric lead zirconate titanate (PZT) particles were used as an example to indicate the working principle. The typical average particle size of PZT particles prepared by hydrothermal method is between 500 and 1000 nm. Through the application of high intensity focused ultrasound (HIFU) to the particles, the average size of the particles is reduced to as small as 10–20 nm. The crystalline structure of the treated particles remains according to the X-ray diffraction (XRD) profiles. Transmission electron microscopy (TEM) shows that the treated particles have identical morphology and size. The nonlinear effects of shock wave introduced by HIFU were studied, and the size reduction results were compared with those by ultrasonic cavitations. Finally, the possible reasons for less damage caused by shock wave were discussed.

The structure of plasma antenna is more complex than metal antenna to reach ideal gain, efficiency, matching, etc. Therefore, earlier plasma antenna prototypes were always featured with larger size and weight. The NSSC research team has developed new prototypes with equivalent performance as metal antenna. In recent research, we also optimized the antenna structure to reduce size and weight. The new plasma antenna prototype is much smaller than the former ones, and its power consumption is also reduced from more than 100 watts to about 30 watts.