Design of A Low-Cost Wireless Indoor Air Quality Sensor Network System

An indoor air quality monitoring system helps in the detection and improvement of indoor air quality. The monitoring systems presently available are very expensive. In this paper, we present a low-cost indoor air quality monitoring wireless sensor network system developed using Arduino, XBee modules, and micro gas sensors. The system is capable of collecting six air quality parameters from different locations simultaneously. We have also developed a linear least square estimation-based method for sensor calibration and measurement data conversion. In this paper, we present the detailed design of wireless air quality sensor node and the calibration method. The performance and usefulness of the system are demonstrated by comparing measurement results of our system with a professional-grade air quality measurement device.     

Effect of B2O3-Bi2O3-SiO2-ZnO glass on the sintering and microwave dielectric properties of 0.83ZnAl2O4-0.17TiO2

The 0.83ZnAl₂O₄-0.17TiO₂ (ZAT) ceramics were synthesized by solid state ceramic route. The effect of 27B₂O₃-35Bi₂O₃-6SiO₂-32ZnO (BBSZ) glass on the microwave dielectric properties of ZAT was investigated. The crystal structure and the microstructure of the ceramic-glass composites were studied by X-ray diffraction and scanning electron microscopic techniques. The low frequency dielectric loss was measured at 1 MHz. The dielectric properties of the sintered samples were measured in the microwave frequency range by the resonance method. Addition of 0.2 wt% of BBSZ improved the dielectric properties with quality factor (Q_u × f) > 120,000 GHz, temperature coefficient of resonant frequency (τ_f) = −7.3 ppm/°C and dielectric constant (?_r) = 11.7. Addition of 10 wt% of BBSZ lowered the sintering temperature to about 950 °C with Q_u × f > 10,000 GHz, ?_r = 10 and τ_f = −23 ppm/°C. The reactivity of 10 wt% BBSZ added ZAT with silver was also studied. The results show that ZAT doped with suitable amount of BBSZ glass is a possible material for low-temperature co-fired ceramic (LTCC) application.     

Photoinduced electron transfer reactions: from the elucidation of old problems in bulk solutions towards the exploration of interfaces

The activities of our research group in the field of photoinduced electron transfer reactions are discussed and illustrated by several examples.     

Adaptive compressive sensing for target tracking within wireless visual sensor networks-based surveillance applications

Wireless Visual Sensor Networks (WVSNs) have gained significant importance in the last few years and have emerged in several distinctive applications. The main aim is to design low power WVSN surveillance application using adaptive Compressive Sensing (CS) which is expected to overcome the WVSN resource constraints such as memory limitation, communication bandwidth and battery constraints. In this paper, an adaptive block CS technique is proposed and implemented to represent the high volume of captured images in a way for energy efficient wireless transmission and minimum storage. Furthermore, to achieve energy-efficient target detection and tracking with high detection reliability and robust tracking, to maximize the lifetime of sensor nodes as they can be left for months without any human interactions. Adaptive CS is expected to dynamically achieve higher compression rates depending on the sparsity nature of different datasets, while only compressing relative blocks in the image that contain the target to be tracked instead of compressing the whole image. Hence, saving power and increasing compression rates. Least mean square adaptive filter is used to predicts target’s next location to investigate the effect of CS on the tracking performance. The tracking is achieved in both indoor and outdoor environments for single/multi targets. Results have shown that with adaptive block CS up to 20 % measurements of data are required to be transmitted while preserving the required performance for target detection and tracking.     

ICTEDCT-CBIR: Integrating curvelet transform with enhanced dominant colors extraction and texture analysis for efficient content-based image retrieval

A novel Integrated Curvelet-based image retrieval scheme (ICTEDCT-CBIR) has been proposed, for the purpose of effectively retrieving more similar images from large digital image databases. The proposed model Integrates Curvelet Multiscale ridgelets with Region-based vector codebook Subband Clustering for enhanced dominant colors extraction and texture analysis. An important ingredient of the curvelet transform is to restore sparsity by reducing redundancy across scales. The discrete curvelet transform makes use of a dyadic sequence of scales, and a bank of filters with the property that the pass band filter is concentrated near the frequencies. An enhanced Region-based vector codebook Sub band Clustering (RBSC) has been proposed for effectively extract dominant colors from the color histogram of the transformed image sub-bands. An integrated matching scheme, based on most similar Highest Priority (MSHP) principle, is used to compare the query and target images. Experimental analysis has been carried out to verify the efficiency of the proposed ICTEDCT-CBIR model. Experimental results showed that the proposed approach has better retrieval performance. First, curvelets capture more accurate texture information. Second, as curvelets are tuned to different orientations, it captured more accurate directional features than wavelets. As the experimental results indicated, the proposed technique outperforms other retrieval schemes in terms of average precision with higher precision-recall crossover point values.     

WCOPP协议在Solectek扩频网桥/路由器中的应用

问题的提出IEEE 802.11b标准的重要一点是采用CSMA/CA（载波检测多址/防碰撞）协议实现宽带接入。CSMA是一个为多点共享资源（如带宽）而设计的协议。如果两个点或两个以上点同时发送数据，碰撞立即发生。在纯粹的CSMA中，这种碰撞是通过碰撞方退回重发来解决。如果再碰撞，则再重发。在CSMA/CA中，是由侦听信道是否空闲的方式来试图避免初次碰撞。只有当信道空闲时，才发送数据，但它不能从根本上避免碰撞，只能减少。在室内无线LAN运用中，CSMA/CA是没有问题的，因为室内无线通信使用接入点（AP）的概念。AP和漫游设备的距…     

Rational-Emotive Behavior Therapy: A Behavioral Change Model for Executive Coaching?

The authors suggest the use of A. Ellis's (1971, 1994) rational-emotive behavior therapy (REBT) as a tool to help clients effect behavioral change in the context of a coaching relationship. The article begins with a brief overview of REBT followed by an argument for its usefulness in an executive coaching context. The authors outline the therapeutic components of REBT that may facilitate executive coaching and discuss the circumstances under which REBT may not be appropriate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of sleep on wake-induced c-fos expression

We investigated the effects of sleep on wake-induced c-fos expression in the cerebral cortex of rats and c-fos-lacZ transgenic mice. In the cortex of rats, the levels of c-Fos, detected both by immunocytochemistry and Western blot, remained high during 6 or 12 hr of enforced wakefulness but declined rapidly (within 1 hr) with increasing time of recovery sleep. Similarly, in the transgenic mice in which lacZ expression is driven from the c-fos promoter, beta-galactosidase activity was high after enforced wakefulness and declined with increasing amounts of sleep. These results suggest that the decrease in c-Fos protein in cortical neurons during sleep may be attributable to cessation of c-fos expression, activation of a process that degrades the wake-induced c-Fos, or both.