Diagonal Based Feature Extraction for Handwritten Alphabets Recognition System using Neural Network

An off-line handwritten alphabetical character recognition system using multilayer feed forward neural network is described in the paper. A new method, called, diagonal based feature extraction is introduced for extracting the features of the handwritten alphabets. Fifty data sets, each containing 26 alphabets written by various people, are used for training the neural network and 570 different handwritten alphabetical characters are used for testing. The proposed recognition system performs quite well yielding higher levels of recognition accuracy compared to the systems employing the conventional horizontal and vertical methods of feature extraction. This system will be suitable for converting handwritten documents into structural text form and recognizing handwritten names

Fabrication-tolerant high quality factor photonic crystal microcavities

A two-dimensional photonic crystal microcavity design supporting a wavelength-scale volume resonant mode with a calculated quality factor (Q) insensitive to deviations in the cavity geometry at the level of Q~2x10^4 is presented. The robustness of the cavity design is confirmed by optical fiber-based measurements of passive cavities fabricated in silicon. For microcavities operating in the lambda = 1500 nm wavelength band, quality factors between 1.3-4.0x10^4 are measured for significant variations in cavity geometry and for resonant mode normalized frequencies shifted by as much as 10% of the nominal value.Comment: 3 pages, 3 figure

Evanescent coupling from optical fiber tapers to photonic crystal waveguides and resonators

Using a coupled mode theory and finite-difference time-domain calculations nearly complete evanescent power transfer between a fiber taper and a photonic crystal defect waveguide which is ideal for probing high-Q cavities is predicted

Nonlinear absorption and dispersion in fiber coupled silicon photonic crystal microresonators

Two-photon absorption, free-carrier absorption and dispersion, and thermo-optic dispersion in high-Q, ultra-small mode volume, photonic crystal cavities are studied experimentally. Sub-nanosecond free-carrier lifetimes, and optical bistability at ∼ 100μW cavity input power are observed

Design of high-Q photonic crystal optical cavities through Fourier space methods

By describing radiation losses through a Fourier space picture of modal couplings, low loss photonic crystal cavities are designed using a group theory-based analysis and finite difference time domain calculations, resulting in predicted quality factors exceeding 10^5

What causes the word gap? Financial concerns may systematically suppress child-directed speech

Parents with fewer educational and economic resources (low socioeconomic-status, SES) tend to speak less to their children, with consequences for children’s later life outcomes. Despite this well-established and highly popularized link, surprisingly little research addresses why the SES “word gap” exists. Moreover, existing research focuses on individual-level explanations with little attention to structural constraints with which parents must contend. In two pre-registered studies, we test whether experiencing financial scarcity itself can suppress caregivers’ speech to their children. Study 1 suggests that caregivers who are prompted to reflect on scarcity—particularly those who reflect on financial scarcity—speak to their 3-year-olds less than a control group in a subsequent play session. Study 2 finds that caregivers speak less to their children at the end of the month—when they are more likely to be experiencing financial hardship—than the rest of the month. Thus, above and beyond the individual characteristics of parents, structural constraints may affect how much parents speak to their children