Challenges of eWALL Wireless Interoperability

Due to development of different technologies there has been significant improvement in quality of life. As a result of that, average person’s lifetime duration has been increased. That triggers the problem of independent living of senior citizens. One of the main concerns of the world today is how to enable senior citizens to live independently. As a response to that, systems like eWALL are being developed. eWALL for Active Long Living is a FP7 funded project and it aims to develop system which will enable elderly people to live independently. These systems consist of a large number of sensors which make wireless sensor network. In this paper, different wireless technologies that can be used for communication in systems that are designed to support independent living of elderly people, have been described. The most important focus is at wireless personal area network technologies, like ZigBee, Bluetooth, Bluetooth Low Energy and wireless local area network technologies (e.g., Wi-Fi). There are many obstacles in designing wireless sensor network and most of them concern energy efficiency and interoperability of different technologies that are being used for communication. The main challenge in the current technology world is tremendous increase of use of various wireless devices and technologies, which can cause relatively high interference, so that the wireless devices can stop working. Using cognitive radio in solving the interoperability problem of different wireless technologies in wireless sensor networks has become interesting research topic. In this paper, research on interoperability of different wireless technologies is presented. Using Spectrum Engineering Advanced Monte Carlo Analysis Tool wireless sensors network in home environment was modelled. Interference based on devices layout and activity was investigated. Also, possible improvements that can be made with cognitive radio are investigated and obtained results are given in this paper.     

Co-channel Interference Energy Harvesting for Decode-and-Forward Relaying

In this paper, co-channel interferences are exploited for energy harvesting in a Cooperative Network (CICN) in which a power constrained relay uses a power splitting architecture (CICN-PS) and a time switching architecture (CICN-TS) to harvest energy from the radio-frequency signals received from a source node and co-channel interferences. In the proposed CICN-PS and CICN-TS protocols, the relay applies decode-and-forward technology to decode the information of the source node, and then forwards the recoded information to a destination with the overall harvested energies. The system performance of the proposed protocols is discussed and evaluated using the exact throughput analyses and is then checked using Monte Carlo simulations over Rayleigh fading channels. The optimal power splitting ratio and energy harvesting time are derived by the Golden Section Search method, and throughput performance evaluations are performed. Our numerical and simulation results show distributions as follows. Firstly, the CICN-PS protocol outperforms the CICN-TS protocol. Secondly, the proposed protocols strictly depend on the location, amount and power of the co-channel interferences. Thirdly, when signal-to-noise ratio increases, the proposed CICN-PS protocol achieves the perfect throughputs where the cooperative relay applies the ideal receiver and co-channel interferences do not affect the destination. Finally, the numerical analyses agree well with the simulation results.     

A Topology Control Approach Reducing Construction Cost for Lossy Wireless Sensor Networks

In lossy wireless sensor networks, many links suffer from significant quality variation with time and environments. Topology control approaches need to consider such stochastic nature to yield different topologies for different application requirements. However, the metric of links must be timely obtained to speed up the topology construction. In fact, the existing approaches address it by passive monitoring, which is not timely adaptive to link quality variation. Also, timely access to the metric of all links at all power levels causes a large burden on topology control operation. We do not insist on getting the link metrics of all power levels at a time. Most urgently needed link metrics are firstly obtained by an active probing mode in this paper. If these link metrics do not meet the topology performance requirements, sub-urgently needed link metrics will be obtained on demand. At the same time, each node performs a topology control process based on the information in a smaller range (e.g., 1-hop neighborhood). Therefore, our approach has the low construct cast, which is proved in this paper. The simulation results also show that our approach outperforms the existing typical works in terms of average transmission power level, though it is slightly less efficient in terms of average delivery rate, average end-to-end delay and total energy consumption. In addition, our approach has advantage in terms of standard deviation of remaining energy under the relatively smaller required path quality bound or lower node density.     

Comparison of Performance of Packet Scheduling Algorithms in LTE-A HetNets

The concept of usage of heterogeneous networks (HetNets) is about improving the LTE system performance by increasing the capacity and coverage of the Macro cell. In this paper, a performance comparison of various packet scheduling algorithms such as Proportional Fair, Maximum Largest Weighted Delay First and Exponential/Proportional Fair is studied in detail in the HetNets environment. The key performance indicators such as throughput, packet loss ratio, delay and fairness are considered to judge the performance of the scheduling algorithms. Various strategies such as increasing the number of Pico cells in the cell edge were used in the simulation for the performance evaluation study. The results achieved through various simulations show that adding Pico cells to the existing Macros enhances the overall system performance in addition to the various scheduling algorithms implemented in Macros. For reader’s convenience, various types of graphs have been used to represent the simulation results to better understand the performance metrics of various scheduling algorithms. Simulation results shows that overall system gain has increased because of adding Picos and thereby providing better coverage in the cell edge areas and thereby increasing the capacity of the network to provide better quality of service.     

The PPG Physiological Signal for Heart Rate Variability Analysis

The photoplethysmography (PPG) sensor can be applied to measure the situation and function of human blood circulation. The PPG sensor is not only existed the characteristics of simple, convenient and low price but also easy non-invasive to measure physiological signal. The advantage of PPG signal is easy to measure from various sensing location. The physiological information of the clinical detection method is broadly implemented for such type. In this paper, we utilize “the green LED reflective” PPG sensor to capture physiological signals operated in static and exercise modes. Therefore, we adopted the short-term measurement in 5 min. Those captured signals are divided into five segments and 1 min for each segment. We calculated heart beats per minute and heart rate variability (HRV) operated in time domain analysis criteria. The related theory of short-time Fourier transform (STFT) combined with power spectral density (PSD) is implemented for finding HRV in frequency domain analysis. Then, we derived random process theory and the autocorrelation function which are verified the PPG measurement is stationary process or not. In the future experiment, we can compare the 24 h data with the previous results. Consequently, we apply the physical health status monitoring of long-term and short-term modes to observe subject varies of HRV and ANS after listening music concurrently.     

A Simple Method for the Growth of Very Smooth and Ultra-Thin GaSb Films on GaAs (111) Substrate by MOCVD

We present a simple thermal treatment with the antimony source for the metal–organic chemical vapor deposition of thin GaSb films on GaAs (111) substrates for the first time. The properties of the as-grown GaSb films are systematically analyzed by scanning electron microscopy, atomic force microscopy, x-ray diffraction, photo-luminescence (PL) and Hall measurement. It is found that the as-grown GaSb films by the proposed method can be as thin as 35 nm and have a very smooth surface with the root mean square roughness as small as 0.777 nm. Meanwhile, the grown GaSb films also have high crystalline quality, of which the full width at half maximum of the rocking-curve is as small as 218 arcsec. Moreover, the good optical quality of the GaSb films has been demonstrated by the low-temperature PL. This work provides a simple and feasible buffer-free strategy for the growth of high-quality GaSb films directly on GaAs substrates and the strategy may also be applicable to the growth on other substrates and the hetero-growth of other materials.     

Stochastic convergence analysis of recursive successive over-relaxation algorithm in adaptive filtering

A stochastic convergence analysis of the parameter vector estimation obtained by the recursive successive over-relaxation (RSOR) algorithm is performed in mean sense and mean-square sense. Also, excess of mean-square error and misadjustment analysis of the RSOR algorithm is presented. These results are verified by ensemble-averaged computer simulations. Furthermore, the performance of the RSOR algorithm is examined using a system identification example and compared with other widely used adaptive algorithms. Computer simulations show that the RSOR algorithm has better convergence rate than the widely used gradient-based algorithms and gives comparable results obtained by the recursive least-squares RLS algorithm.     

Sharpening filter for false color imaging of dual-energy X-ray scans

Dual-energy X-ray imaging has a vast range of application in security. Luggage inspection is an essential process for an airplane or court house security as well as securing mass events. An image of a content of some package may help to figure out if there is any dangerous object inside and avoid possibly threatening situation. As the raw X-ray images are not always easy to analyze and interpret, some image processing methods like an object detection, a frequency resolution increase or a pseudocoloring are being used. Since color can be a powerful tool to improve the usefulness of an information display, we propose pseudocoloring improvement by modifying material-based approach with edge detection to fill and sharpen color layers over the image making it easier to read and analyze. We demonstrate the effectiveness of the methods using real data, acquired from a professional dual-energy X-ray scanner.     

Analysis of fractal inter frame video coding using parallel approach

Digital video has many applications varying from telecommunications to broadcasting and so on. Video compression techniques have evolved over the past two decades with prominent technique being developed using fractal. However, this technique was not so popular because of its computationally intensive nature. This paper proposes an inter frame video compression technique, which consists of a combination of a block matching using fractal compression. The proposed algorithm is implemented on CUDA-enabled GPU which significantly reduces the encoding time of the video and provides a very high compression ratio with reasonable quality of the decoded video. Extensive simulations were carried out to analyze the performance of the proposed algorithm.