Yaojie Sun

Research on Facial Recognition and Color Identification under CMH and HPS Lamps for Road Lighting

Abstract Two experiments involving facial recognition and color identification have been done to evaluate the performance of road lighting with HPS and CMH. 48 subjects took part in the facial recognition experiment, and 43 in the color identification experiment, aged 20 to 40. In the facial recognition experiment we used 8 cards with different head portraits for subjects to identify. Three distances were recorded to compare the discriminability: when the subjects could just recognize the gender, guess the identity of the person, and make sure of the identity. In the color identification experiment, participants were asked to identify 8 color cards under HPS and CMH. Results showed that it is easier to recognize faces under CMH. The identification of yellow, green and blue color under CMH is significantly better, while identification of yellow-green under HPS is significantly better.

Transient effects of harsh luminous conditions on the visual performance of aviators in a civil aircraft cockpit.

The aim of this work was to examine how harsh luminous conditions in a cockpit, such as lightning in a thunderstorm or direct sunlight immediately after an aircraft passes through clouds, may affect the visual performance of pilots, and how to improve it. Such lighting conditions can result in the temporary visual impairment of aviators, which may greatly increase the risk of accidents. Tests were carried out in a full-scale simulator cockpit in which two kinds of dynamic lighting scenes, namely pulse changed and step changed lighting, were used to represent harsh luminous conditions. Visual acuity (VA), reaction time (RT) and identification accuracy (IA) were recorded as dependent variables. Data analysis results indicate that standardized VA values decreased significantly in both pulsing and step conditions in comparison with the dark condition. Standardized RT values increased significantly in the step condition; on the contrary, less reaction time was observed in the pulsing condition. Such effects could be reduced by an ambient illumination provided by a fluorescent lamp in both conditions. The results are to be used as a principle for optimizing lighting design with a thunderstorm light.

Health education about hypertension in the elderly in rural Chinese villages

This study sought to examine baseline knowledge of hypertension among the elderly in rural western Chinese villages and to evaluate whether educational programs could improve their knowledge towards better hypertension prevention and management. We conducted a 25-day health education about hypertension, including health lectures, personal consultation and distribution of health pamphlets, etc., for 1182 randomly assigned elderly people in Shaanxi Province, P. R. China, during the period from June to September, 2007. All subjects received a questionnaire-based survey and then a 25-day health education on hypertension. Poor knowledge regarding the causes and preventive measures of hypertension was observed in these aged participants before implementation of the health education. However, their overall knowledge of hypertension was significantly improved after the health education (P<0.05). Health education can greatly improve knowledge of hypertension, which may help to reduce the risk of hypertension in the elderly.

An intelligent lighting control system based on ergonomic research

In this paper an intelligent lighting control system is introduced with adjustable illuminance, uniformity, correlated color temperature (CCT) and duration and transition of different modes, whose control strategy is based on the ergonomic research. It is verified by ergonomic experiments to be a suitable adjustable system to meet different situation of human needs.

Luminance Determination of CPA and PBAs in Aircraft Cockpits Based on Ergonomic Research

This paper reports on the experiments undertaken to determine the luminance of control panel assembly (CPA) and push button annunciate (PBA) in cockpits when operated in low and high ambient environment. Referring to the varying ways of commercial airplanes are illuminated, different levels of luminance are chosen to be tested. Psychology scales that measure comfort and legibility when under illumination are used as the two main evaluation indexes, which reflecting the performance of CPA and PBAs with different luminance levels according to the observers’ evaluation scores. 21 observers participated in the study, in which they were asked to give certain assessment. The results suggest that for both fully dark environment and the environment that only has light from the working displays, 0.4fl is the preferable luminance for CPA. For PBAs of different colors, the preferable luminance range is also different.

The Selective Harmonic Detection for the Integration Photovoltaic Generation and Active Power Filter

To improve the utilization of the inverter of the photovoltaic grid connected systems and decrease the harmonic of the grid, a novel selective harmonic detection method based on the synchronous rotator frame is proposed. Utilizing three-phase Park transform, the rotator vector is transferred to the static vector, and the synchronous harmonic is separated and acquired. The characteristic of negative and positive sequence harmonic is fleetly and exactly presented in all frequency domains. Additional, a new control strategy based on this harmonic detection is proposed for the integration photovoltaic grid connected generation and active power filter. Validity and practicality of the proposed selective harmonic detection method and control strategy are proved.

Intelligent Sliding Mode Control for Variable-Speed Wind Conversion System with a Characteristic Model

In this paper, we present a novel method for designing a controller with good rubustness for variable-speed wind energy conversion systems based on a characteristic model. Due to the stochastic operating conditions and the inevitable nonlinear characteristics inherent in the system, the dynamic model is usually too complex for the system analysis and controller design. Therefore, we first develop a detailed plant characteristic model of a variable-speed wind energy conversion system, which simplifies significantly the engineering implementation. Then the sliding mode incorporating fuzzy tuning schemes is applied to design a controller that optimizes the converter system efficiency and robustness. Analysis and experimentation show that the method achieves satisfactory wind energy tracking.

Usability of Using Polarized Filter for Reading Lamp to Reduce Disturbing Reflected Glare

In this paper the usability of using polarized filters for reading lamp to reduce disturbing reflected glare was tested based on a within-subject design ergonomic research. Results show that with the increasing polarization degree the subjective rating score decreases, which means that increasing polarization of the optical film reduces the reflected glare. Statistical analysis shows that there is high correlation (0.05 level, 2-tailed) between the subjective rating score on reflected glare and the degree of polarization. An univariate analysis of variance proves that the different evaluation caused by the optical films with different polarization degrees has statistically significant meaning (F=108.4, p<0.001). The results of this research is very useful for optical design of reading lamp, which occupies a big market in China, affecting the visual comfort of huge numbers of readers, such as students and office people.

Stability Analysis of the Series-In Series Hybrid Active Power Filter

For the important characteristic of the system stability, a state-space averaging model of the series-in series hybrid active power filter (SHAPF) is constructed to analyze its system stability by traditional control strategy taking into account the effect of the time delay in the digital control system, inverter, low pass filter and second-order carrier-wave filter. Based on the analysis of the close-loop control model, the traditional control strategy of the series-in SHAPF is an unstable system. A new control strategy is proposed to reduce the impact of the high frequency current interference and improve its stability and filter performance of the series-in SHAPF. Validity and practicality of the proposed control strategy are proved by simulation analytical and experiment results from a 10-kW laboratory system.