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In this work, RGO/SnO 2 nanocomposites films were airbrushed on interdigitated electrodes to prepare gas sensors. The films were characterized by SEM, XRD and Raman. The sensing performance to NO 2 gas was investigated at room-temperature. The experimental results showed that moderate SnO 2 nanoparticles enhanced the response of the sensors. The optimum amount of SnO 2 is 40mg, whose response is 39.1% toward 50ppm NO 2 .

In this work, a fundamental new approach for humidity detection was proposed. By coupling triboelectric nanogenerator (TENG) with resistive humidity sensor, the degree of ambient moisture can be actively detected at room temperature, where the voltage drop across the interdigital electrodes (IDEs) has a reversely proportional relationship with relative humidity. The prepared self-powered triboelectric humidity sensor (THS) holds high humidity response of ∼7, fast response/recovery time of 2.8 s and 3.5 s, stable repeatability and excellent long term stability. With respect to selectivity, the response of THS to gaseous water was at least 2-fold higher than those for other gases. Furthermore, through a signal processing circuit, a self-powered humidity alert system was developed for real-time monitoring the ambient humidity. Finally, the underlying working principle of the proposed sensor was discussed in detail. This research not only provides a simple, low-cost and efficient means in humidity sensing but also greatly broadens the applicability of TENGs as self-powered active sensors.

Well-aligned ZnO nanorod array films with various morphologies are prepared on Au/Ti interdigital electrodes (IDEs) by changing the concentration of growth solution using a mild hydrothermal process. A feasible mechanism for controlling their growth is discussed. The UV-enhanced gas sensing results reveal that smaller rod diameter and higher density array can improve the response of sensors based on ZnO nanorod array films to O 2 gas, while slower desorption of O 2 molecules on the nanorod surfaces is found for the higher-density array films.

A new approach was proposed to evaluate the performance of organic thin film transistors (OTFTs) gas sensors. Back-gated OTFTs gas sensors with poly (3-hexylthiophene) (P3HT)/Zinc oxide (ZnO) nanorods composite film as the active layers and gas sensing layers were prepared for nitrogen dioxide (NO2) detection. Electrical parameters of OTFTs based on pure P3HT film and P3HT/ZnO-nanorods composite film were calculated and analyzed. Response characteristics of gas sensors to NO2 were studied. It can be found that responses of OTFTs gas sensors were inaccurate according to conventional definition. The slope of fitting line (ΔI versus log t) was proposed as a new method to evaluation gas properties of OTFTs sensors. The calculate results illustrated that the sensitivity can be increased 40.2% due to appropriate amount of ZnO-nanorods doping.

In this paper, hetero-junction structure of composite film based on α-6T/ PC61BM was firstly utilized as active layer of OTFT gas sensor for detecting ammonia gas (NH3). The electrical characteristics, gas sensing performances based on α-6T/PC61BM composite film and pure α-6T film were tested and compared. It could be found that the sensitivity of α-6T/PC61BM composite film was much higher than pure α-6T film, increasing from 1.02 × 10−3 ppm−1 to 3.63 × 10−3 ppm−1. In addition, the sensing mechanisms of all sensors were studied as well.

Environment change induces a great influence on mouse heartbeat. The Poincare plot and the first-order differential (FOD) plot are usually introduced to analyze heart rate variability (HRV), while both of them are qualitative methods to the research object. A quantitative approach is suggested to analyze abnormal HRV based on the FOD radius in this paper. Based on FOD sequence between the RR intervals, we get the FOD plot. FOD radius is estimated which divide FOD plot into two different regions: normal and abnormal region. So we get the information containing classification of RR intervals. Our research results show that, Concentrated Ambient Particles (CAPs) have significant adverse health effects on both healthy and unhealthy mice, and it's much more sensitive to unhealthy mice.

A fast priority index (PID) assignment algorithm is developed for the MGS (Medium Grain Scalability) packets in the scalable extension of the H.264/AVC. The contributions of the paper are threefold. First, we formulate the index assignment problem as the quantization of the rate-distortion (R-D) slopes of MGS packets, and use the Lloyd-Max algorithm to find the optimal solution. The slope quantization index of a packet is used as its PID. The complexity of our method is much lower than existing method. Secondly, the quantization-based PIDs facilitate the comparisons of packets from different video streams. Video multiplexing results show that the overall PSNR can be improved up to 1 dB. Finally, we propose some real-time and adaptive implementations of the proposed method, which have the same performance as the offline method.

We propose a cross-layer optimization framework for multi-session broadcast/multicast (BC/MC) over multimedia network. The proposed framework seeks to perform simultaneous adaptations via intelligent co-operations between satellite gateway, terrestrial gap-fillers and respective BC/MC receivers to cope with highly vibrating satellite link, which is severely constrained by propagation delay, transponder power and channel bandwidth. By jointly optimizing multiple performance criteria across protocol stacks, the scheme mitigates the adverse impacts induced by queuing dynamics, channel variations and user diversities, thereby encompassing channel-dependant and network-friendly features. Meanwhile, it well accommodates return link diversity and the imperfect feedbacks, whilst ensuring fairness, scalability and robustness. We evaluate its performance over diverse network and media configurations in comparison with the state-of-the-art approaches. Numerical results show that simultaneous performance gains can be obtained on multiple essential performance metrics.

With their inherent broadcast capacities and reliable extensive geographical coverage, the broadband satellite networks are emerged as a promising approach for the delivery of multimedia services in 3G and beyond systems. To utilise the available resources in an optimized way whilst guaranteeing the diverse quality-of-service (QoS) demands, an Adaptive QoS-aware Resource Allocation (AQRA) scheme is proposed in this paper for multimedia delivery in satellite broadcasting networks. By taking into account essential aspects of a successful QoS provisioning whilst preserving the system power/resource constraints, the proposed scheme is capable of allocating the resources, in an adaptive manner, according to the current QoS satisfaction of each session. Simulation results prove that the AQRA achieves significantly better performance than those of existing schemes on multiple performance metrics.

This paper studies the optimization techniques for scheduling multimedia packets in satellite digital multimedia broadcasting system, namely SDMB, in the presence of a return link via terrestrial mobile networks. We propose a novel approach, called proportional channel-aware packet scheduling (PCPS) scheme, to prioritize and allocate radio resources in response to the end-to-end behaviors, queuing dynamics and channel variations associated with each user in the broadcast/multicast group. In comparison with existing channel-independent scheduling schemes, simulation results prove that the proposed scheme can significantly reduce the round trip delay (RTD), improve the throughput and achieve better fairness, whilst enjoying low computational complexity, high flexibility and good scalability features.

This paper studies an efficient solution for transporting scalable video over multi-standard integrated multimedia broadcasting networks, namely DVB-H and DTMB. A novel approach, called network-aware stream adaptation (NASA) framework, is developed within this context to deliver the scalable video streams to the end users over the underlying heterogeneous broadcasting standards. Simulation results prove that the proposed scheme significantly improves the channel utilization and achieves better video quality. An efficient dynamic stream adaptation (DSA) mechanism is then foreseen to perform the most appropriate stream adaptation in response to the current reception conditions, network resources, and channel variations, offering progressive perceived visual display quality and fine-granularity QoS performance.

With the unique broadcast nature and ubiquitous coverage of satellite network, the synergy between satellite and terrestrial networks provides new opportunities for delivering wideband services to a wide range of audiences over extensive geographical areas. This paper concerns the optimization techniques pertinent to the packet scheduling to facilitate multimedia content delivery over the satellite with a return channel via terrestrial network. We propose a novel hierarchical packet scheduling (HPS) scheme, which allocates the resources at different parts of the network in an adaptive and QoS-aware manner, in response to traffic dynamics in the networks as well as link variations of each user. Simulations prove that the proposed HPS scheme can effectively improve the end-to-end performance and resource utilization.

Channel mapping is an important issue in the radio resource allocation scheme for the Satellite Digital Multimedia Broadcast (SDMB) system. Existing single-level channel multiplexing scheme performs well only when the bit rate of logical channel exactly matches the corresponding bit rate of the transport channel. In this paper, a novel 2-level channel multiplexing approach is proposed and developed. It performs channel multiplexing at both transport and physical channels, and applies optimised 2-stage bin-packing algorithm for the channel mapping. The results show that, in comparison with existing channel mapping schemes, our approach can require less number of transport channels, has better usage of the residual capacity on the transport channels, and can improve the total transmission capacity on the logical channels.

This paper presents a novel approach for the radio source allocation as part of the overall radio resource management scheme for the satellite digital multimedia broadcast (SDMB) system. A two-stage bin-packing algorithm is signed and employed for channel mapping which considers multiplexing at both the transport and physical channels so as to achieve the highest possible degree of utilization and efficiency of the available system capacity. Evaluations of these schemes are performed for various traffic mixes and physical channel configuration scenarios