1,185 research outputs found
Elite Foreign Policy-Making Regarding Israel: A Comparison Between Jordan and Lebanon
This thesis argues that external foreign powers, namely the United States and Syria, influenced foreign policy elites in Jordan and Lebanon to either pursue or reject normalization agreements with Israel throughout history. This thesis also examines how elite foreign policy-makers shape Lebanese and Jordanian public opinion through their policies with Israel
Channel modeling for overhead line equipment for train communication
The demand for high-speed data access to railway infrastructure and internet broadband data in railway is increasing due to the high density of the trains and passengers. Currently, communication access in trains is based on radio frequency (RF) wireless access networks that are slow and insufficient for the demands of the high-speed railway (HSR) and its customers. However, performance, service attributes, frequency band, and industrial support should be considered for the selection of a suitable communication system that can fulfill the requirements of HSR operation. This paper investigates overhead line equipment (OLE) as access network connecting trains to the backbone communication networks. The ABCD transmission model is used to represent the transfer function of the OLE channel. It was shown that transmission over OLE is affected by the frequency and link distance. The simulation results also show that the channel gain of the OLE channel attenuated faster at higher speeds compared to train movement at lower speeds
Performance analysis of cooperative and non-cooperative relaying over VLC channels
The line-of-sight (LoS) channel is one of the requirements for efficient data transmission in visible-light communications (VLC), but this cannot always be guaranteed in indoor applications for a variety of reasons, such as moving objects and the layout of rooms. The relay-assisted VLC system is one of the techniques that can be used to address this issue and ensures seamless connectivity. This paper investigates the performance of half-duplex (HD) conventional DF relay system and cooperative systems (i.e., selective DF (SDF) and incremental DF (IDF)) over VLC channels in terms of outage probability and energy consumption. Analytical expressions for both outage probability and the minimum energy-per-bit performance of the aforementioned relaying systems are derived. Furthermore, Monte Carlo simulations are provided throughout the paper to validate the derived expressions. The results show that exploiting SDF and IDF relaying schemes can achieve approximately 25% and 15% outage probability enhancement compared to single-hop and DF protocols, respectively. The results also demonstrate that the performance of the single-hop VLC system deteriorates when the end-to-end distances become larger. For example, when the vertical distance is 3.5m, the single-hop approach consumes 20%, 40% and 45% more energy in comparison to the DF, SDF, and IDF approaches, respectively
On the performance of DF-based power-line/visible-light communication systems
This paper presents a comprehensive performance analysis of an integrated indoor power line communication (PLC)/visible light communication (VLC) system with the presence of a decode-and-forward (DF) relay. The existing indoor power line networks are used as the backbone for VLCs. The performance of the proposed system is evaluated in terms of the average capacity and the outage probability. A new unified mathematical method is developed for the PLC/VLC system and analytical expressions for the aforementioned performance metrics are derived. Monte Carlo simulations are provided throughout the paper to verify the correctness of the analysis. The results reveal that the performance of the proposed system deteriorates with increasing the end-to-end distance and improves with increasing the relay transmit power. It is also shown that the outage probability of the system under consideration is negatively affected by the vertical distance to user plane
Neutral processes dominate microbial community assembly in Atlantic salmon, Salmo salar
In recent years a wealth of studies have examined the relationships between a host and its microbiome across diverse taxa. Many studies characterise the host microbiome without considering the ecological processes that underpin microbiome assembly. In this study, the intestinal microbiota of Atlantic salmon, Salmo salar, sampled from farmed and wild environments was first characterised using 16s rDNA MiSeq sequencing analysis. We used neutral community models to determine the balance of stochastic and deterministic processes that underpin microbial community assembly and transfer across lifecycle stage and between gut compartments. Across gut compartments in farmed fish, neutral models suggest that most microbes are transient with no evidence of adaptation to their environment. In wild fish, we find declining taxonomic and functional microbial community richness as fish mature through different lifecycle stages. Alongside neutral community models applied to wild fish, we suggest declining richness demonstrates an increasing role for the host in filtering microbial communities that is correlated with age. We find a limited subset of gut microflora adapted to the farmed and wild host environment among which Mycoplasma sp. are prominent. Our study reveals the ecological drivers underpinning community assembly in both farmed and wild Atlantic salmon and underlines the importance of understanding the role of stochastic processes such as random drift and small migration rates in microbial community assembly, before considering any functional role of the gut microbes encountered
Robust CNN architecture for classification of reach and grasp actions from neural correlates: an edge device perspective
Brain-computer interfaces (BCIs) systems traditionally use machine learning (ML) algorithms that require extensive signal processing and feature extraction. Deep learning (DL)-based convolutional neural networks (CNNs) recently achieved state-of-the-art electroencephalogram (EEG) signal classification accuracy. CNN models are complex and computationally intensive, making them difficult to port to edge devices for mobile and efficient BCI systems. For addressing the problem, a lightweight CNN architecture for efficient EEG signal classification is proposed. In the proposed model, a combination of a convolution layer for spatial feature extraction from the signal and a separable convolution layer to extract spatial features from each channel. For evaluation, the performance of the proposed model along with the other three models from the literature referred to as EEGNet, DeepConvNet, and EffNet on two different embedded devices, the Nvidia Jetson Xavier NX and Jetson Nano. The results of the Multivariant 2-way ANOVA (MANOVA) show a significant difference between the accuracies of ML and the proposed model. In a comparison of DL models, the proposed models, EEGNet, DeepConvNet, and EffNet, achieved 92.44 ± 4.30, 90.76 ± 4.06, 92.89 ± 4.23, and 81.69 ± 4.22 average accuracy with standard deviation, respectively. In terms of inference time, the proposed model performs better as compared to other models on both the Nvidia Jetson Xavier NX and Jetson Nano, achieving 1.9 sec and 16.1 sec, respectively. In the case of power consumption, the proposed model shows significant values on MANOVA (p < 0.05) on Jetson Nano and Xavier. Results show that the proposed model provides improved classification results with less power consumption and inference time on embedded platforms
Two-Stage Non-Orthogonal Multiple Access over Power Line Communication Channels
Non-orthogonal multiple access (NOMA) has recently been proposed for dual-hop cooperative relaying power line communication (PLC) systems. Unlike conventional NOMA-PLC schemes which deploy NOMA only at the relay, this paper proposes to enhance the performance of such systems by implementing the principle of NOMA at both the source and relaying modems. The system performance is evaluated in terms of the average sum capacity for which analytical expressions are derived for both the improved and conventional NOMA-PLC systems. Throughout our analysis, the PLC channel is assumed narrow-band modeled with log-normal amplitude distribution and the total PLC noise consists of both background and impulsive noise. Monte Carlo simulations are provided to corroborate the accuracy of our theoretical analysis. The derived expressions are utilized to examine the impact of various system parameters on the average capacity performance; this includes: impulsive noise probability, network branching, power allocation coefficients and transmit power. The optimization problem of the power allocation coefficients is also addressed for both NOMA-PLC systems under consideration. Results reveal that significant gains in the average capacity can be attained with the improved NOMA-PLC approach compared to the conventional system. In addition, the improved system is able to meet a given performance requirement with smaller transmit power offering more relaxed electromagnetic compatibility issues associated with PLCs. Finally, it is demonstrated that optimizing the power allocation coefficients at both the source and relay modems is crucial to maximize performance
Purification and medium optimization of α-amylase from Bacillus subtilis 168
α-Amylase was first time isolated and purified from Bacillus subtilis 168 (1A1). Purified α-amylase fraction showed a single protein band with a molecular weight of 55 kD. Chemical characterization of the purified α-amylase revealed optimum amylolytic activity at 37°C and pH 7.0 using starch as substrate. It was stable at pH 5.0 to 9.0 and at temperatures 25–70°C. Culture conditions were optimized by using statistics-based experimental designs to enhanced α-amylase (EC.3.2.1.1) production. A two level fractional factorial Plackett-Burman design was used for the preliminary screening significant media components and conditions. Response surface methodology (RSM) involving a 24 full-factorial central composite design (CCD) and a second-order polynomial equation was then employed to identify the relationship between the α-amylase yield and the four significant variables. Optimal levels of the significant variables for the maximum α-amylase yield were starch 2.55 g/l, yeast extract 8.4 g/l, sodium chloride 8.1% and 48 h of incubation. Mean value of α-amylase yield was 639.7 IU/ml, which was in excellent agreement with the predicted value (633.5 IU/ml).Key words: Bacillus, α-amylase, optimization, Plackett-Burman design, response surface methodology
Virtual reality as a non-conventional rehabilitation for stroke: : A comprehensive review
The authors thank Michael Irvine, PhD, from Liwen Bianji (Edanz) (www.liwenbianji.cn) for editing the English text of a draft of this manuscript.Peer reviewe
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