Exoelectron emission from ion-implanted MgO single crystals

Thermally stimulated exoelectron emission (TSEE) measurements were carried out for pure MgO single crystals, annealed and then irradiated to either ion beams of different doses and energies or X-rays. H⁺- and He⁺-ion implantation causes an increase of the TSEE yield compared to that of nonimplanted samples. The TSEE response is dependent on the dose and energy of the implanted ions.     

Ab initio study of the electronic and optical properties of sillimanite (Al2SiO5) crystal

Ab initio calculations based on the density functional theory (DFT) are used to investigate the electronic and optical properties of sillimanite. The geometrical parameters of the unit cell, which contain 32 atoms, have been fully optimized and are in good agreement with the experimental data. The electronic structure shows that sillimanite has an indirect band gap of 5.18 eV. The complex dielectric function and optical constants, such as extinction coefficient, refractive index, reflectivity and energy-loss spectrum, are calculated. The optical properties of sillimanite are discussed based on the band structure calculations. It is shown that the O-2p states and Al-3s, Si-3s states play the major role in optical transitions as initial and final states, respectively.     

A novel adaptive morphological approach for degraded character image segmentation

This work proposes a novel adaptive approach for character segmentation and feature vector extraction from seriously degraded images. An algorithm based on the histogram automatically detects fragments and merges these fragments before segmenting the fragmented characters. A morphological thickening algorithm automatically locates reference lines for separating the overlapped characters. A morphological thinning algorithm and the segmentation cost calculation automatically determine the baseline for segmenting the connected characters. Basically, our approach can detect fragmented, overlapped, or connected character and adaptively apply for one of three algorithms without manual fine-tuning. Seriously degraded images as license plate images taken from real world are used in the experiments to evaluate the robustness, the flexibility and the effectiveness of our approach. The system approach output data as feature vectors keep useful information more accurately to be used as input data in an automatic pattern recognition system.     

Novel nonspeech tones for conceptualizing spatial information

We propose a novel concept toward interfaces that can provide visually impaired persons with the opportunity to recover the freedom to conceptualize their environment without depending on conventional voice synthesizer systems. Fourteen subjects participated in ten experiments to provide results that evaluated their performances to conceptualize spatial information based on cues in “artificial-sounding” (AS) and “natural-sounding” (NS) tones. The source of AS tones was the digitized sound used by the vOICe Learning Edition, and the source of NS tones was fan noise with analogs in everyday listening. Experimental results revealed that the use of NS tones was essential for improving the conceptualization performance of subjects as the eventual users of novel human–environment interfaces. This work was presented in part at the 11th International Symposium on Artificial Life and Robotics, Oita, Japan, January 23–25, 2006