Modulation efficiency of LiNbO₃ waveguide electro-optic intensity modulator operating at high microwave frequency

The modulation efficiency, at high-frequency microwave modulation, of a LiNbO3 waveguide electro-optic modulator is shown to be degraded severely, especially when it is used as a frequency translator in a Brillouin-distributed fiber-sensing system. We derive an analytical expression for this attenuation regarding the phase-velocity mismatch and the impedance mismatch during the modulation process. Theoretical results are confirmed by experimental results based on a 15 Gb/s LiNbO3 optical intensity modulator

A digital grayscale generation equipment for image display standardization

The standardization of grayscale display is essentially significant for image signal communication, transmission, and terminal reading. The key step of this standardization is establishing a traceable equipment of grayscale. As a relative value, grayscale is transferred to two different absolute values to satisfy different traceability methods, including optical density for hardcopy image and luminance for softcopy. For luminance, a generation equipment is designed to build the relationship between luminance and grayscale. In this work, novel equipment is established using digital light processing (DLP) by time-frequency modulation, and the corresponding uncertainty is analyzed. The experiment result shows that this digital equipment builds the relationship between grayscale and luminance in the range of 0.16-4000 cd/m2. It enables traceable measurement of grayscale to luminance on this equipment with high accuracy and can provide a standardized reference for the display of grayscale images in the fields of medicine, remote sensing, non-destructive testing, etc.</jats:p

The influence of structural defects on intra-granular critical currents of bulk MgB2

Bulk MgB2 samples were prepared under different synthesis conditions and analyzed by scanning and transmission electron microscopy. The critical current densities were determined from the magnetization versus magnetic field curves of bulk and powder-dispersed-in-epoxy samples. Results show that through a slow cooling process, the oxygen dissolved in bulk MgB2 at high synthesis temperatures can segregate and form nanometer-sized coherent precipitates of Mg(B,O)2 in the MgB2 matrix. Magnetization measurements indicate that these precipitates act as effective flux pinning centers and therefore significantly improve the intra-grain critical current density and its field dependence.Comment: 4 pages, 4 figures, to be published in IEE Transactions in Applied Superconductivit

Audeosynth: music-driven video montage

We introduce music-driven video montage, a media format that offers a pleasant way to browse or summarize video clips collected from various occasions, including gatherings and adventures. In music-driven video montage, the music drives the composition of the video content. According to musical movement and beats, video clips are organized to form a montage that visually reflects the experiential properties of the music. Nonetheless, it takes enormous manual work and artistic expertise to create it. In this paper, we develop a framework for automatically generating music-driven video montages. The input is a set of video clips and a piece of background music. By analyzing the music and video content, our system extracts carefully designed temporal features from the input, and casts the synthesis problem as an optimization and solves the parameters through Markov Chain Monte Carlo sampling. The output is a video montage whose visual activities are cut and synchronized with the rhythm of the music, rendering a symphony of audio-visual resonance.postprin

Validity and reliability of a phone App and stopwatch for the measurement of 505 change of direction performance: a test-retest study design

Purpose: The aim of this study was to explore the validity and reliability of a phone app (named: COD timer) and stopwatches for the measurement of change of direction (COD) performance. Methods: Sixty-two youth basketball players (age: 15.9 ± 1.4 yrs, height: 178.8 ± 11.0 cm, body mass: 70.0 ± 14.1 kg) performed six trials of 505 COD test (with the left side being the plant leg first, then the right side). The completion time was measured simultaneously via timing gates (with error correction processing algorithms), the phone app and stopwatches. Results: There was an almost perfect correlation and agreement between timing gates and COD timer (r = 0.978; SEE = 0.035 s; LoA =-0.08~0.06 s), but a lower correlation and agreement between timing gates and stopwatch (r = 0.954; SEE = 0.050 s; LoA =-0.17~0.04 s) with statistical significance in completion time (ES = 1.29, 95%CI: 1.15-1.43, p < 0.01). The coefficient of variation revealed similar level of dispersion between the three timing devices (timing gates: 6.58%; COD timer: 6.32%; stopwatch: 6.71%). Inter-observer reliability (ICC = 0.991) and test-retest reliability (ICC = 0.998) were excellent in COD timer, while the inter-observer reliability was lower (ICC = 0.890) in the stopwatches. Conclusion: In the 505 COD test, the COD timer was able to provide a valid and reliable measurement. On the contrary, stopwatch was not recommended because of large error. Thus, if timing gates are unavailable, practitioners can adopt the COD timer app to assess 505 COD speed times

Waste management in Cange, Haiti

Our goal is to create a self-sustained waste management system in order to improve the sanitation and environmental health in Cange, Haiti. Cange currently has no waste management system; garbage is either piled in ravines or burned. We have divided Cange\u27s waste into three waste streams for treatment: organics, plastics, and other. The organics will be primarily treated with municipal scale composting windrows and the finished compost will be sold to surrounding farms. The plan for the plastic materials is to work with merchants to minimize the need and use of disposable plastic, repurpose used plastic waste into other marketable items (e.g., woven bags, construction blocks, etc.), and to recycle them at a newly formed micro-recycling facility. Other materials are expected to be mainly construction debris, which is already widely repurposed by the community, so it will be collected in a central refuse pile. In conclusion, we believe this system will effectively process the waste in a beneficial manner to the community