价格已经提高到了过去几十年从未见过的水平

从海湾合作委员会(GCC)生活用纸制造业的前景来看,回顾2021第四季度,或许中东、北非和远东地区的每位参与者都对供应链困境感到惊讶,其中大部分原材料供应比以往任何时候都要困难得多。这对供需前景造成了严重的负面影响,由于缺乏供应,需求大幅增加。然而,这个消极因素很可能会产生市场的连锁反应。价格也提高到了过去几十年从未见过的水平。纸张供应商之间的价格战以前从未发生过,值得注意的是,尽管销售量减少,但利润率令人惊讶地满意。从海湾合作委员会(GCC)一些首次公开募股(IPO)公司公布的业绩,就能理解与一年前的同期相比业绩明显向好。     

A novel MEMS tunable antenna with wide tuning range of frequency

In this paper a novel MEMS tunable CPW antenna with wide tuning range of frequency is presented. The antenna’s frequency tuning range increment is achieved by loading three novel large tuning range capacitors at radiation edge of antenna patch. Two techniques are employed for increasing the capacitors tuning range. First, dual gap technique is used to overcome the pull-in limitation and then two lateral beams are added in order to parallel movement of capacitive plate which increases the capacitance value. The simulation result shows that the resonance frequency tuning range of antenna increased from 1.96 GHz loaded by traditional capacitor to 6.89 GHz using the new capacitor structure. Also in resonance frequency, the antenna has a good impedance matching with transmission line even in high capacitance values.     

Design of a printed log‐periodic dipole array antenna with high gain for millimeter‐wave applications

In this article, a V‐band printed log‐periodic dipole array (PLPDA) antenna with high gain is proposed. The antenna prototype is designed, simulated, fabricated, and tested. Simulation results show that this antenna can operate from 42 to 82 GHz with a fractional impedance bandwidth of 64.5% covering the whole V‐band (50–75 GHz). The antenna has a measured impedance matching bandwidth that starts from 42 to beyond 65 GHz with good agreement between the experimental and simulated results. At 50 and 65 GHz, the antenna has a measured gain of 10.45 and 10.28 dBi, respectively, with a gain variation of 2.6 dBi across the measured frequency range. The antenna prototype exhibits also stable radiation patterns over the operating band. It achieves side‐lobe suppression better than 17.26 dB in the H‐plane and better than 8.95 dB in the E‐plane, respectively. In addition, the cross‐polarization component is 18.5 dB lower than the copolarization with front‐to‐back ratio lower than 24.1 dB in both E‐ and H‐planes across the desired frequency range. Based on a comparison of performance among the reported work in the literature, we can say that the proposed PLPDA antenna is a proper candidate to be used in many applications at V‐band frequency. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:185–193, 2015.     

Reconstruction of a complex-valued object in double-passage coherent imaging through a random-phase screen

We consider the reconstruction of a complex-valued object that is coherently illuminated and viewed through the same random-phase screen. The reconstruction is based on two intensity measurements: the intensity of the Fourier transform of the image and the intensity of the Fourier transform of the image when modulated with an exponential filter. The illumination beam has a Gaussian intensity profile of arbitrary width, and the phase screen is assumed to be described by a Gaussian random process of large variance and arbitrary correlation length. Computer-simulated examples of the reconstruction of a two-dimensional complex object demonstrate that the reconstruction is robust.     

Big Data Analytics: Deep Content-Based Prediction with Sampling Perspective

The world of information technology is more than ever being flooded with huge amounts of data, nearly 2.5 quintillion bytes every day. This large stream of data is called big data, and the amount is increasing each day. This research uses a technique called sampling, which selects a representative subset of the data points, manipulates and analyzes this subset to identify patterns and trends in the larger dataset being examined, and finally, creates models. Sampling uses a small proportion of the original data for analysis and model training, so that it is relatively faster while maintaining data integrity and achieving accurate results. Two deep neural networks, AlexNet and DenseNet, were used in this research to test two sampling techniques, namely sampling with replacement and reservoir sampling. The dataset used for this research was divided into three classes: acceptable, flagged as easy, and flagged as hard. The base models were trained with the whole dataset, whereas the other models were trained on 50% of the original dataset. There were four combinations of model and sampling technique. The F-measure for the AlexNet model was 0.807 while that for the DenseNet model was 0.808. Combination 1 was the AlexNet model and sampling with replacement, achieving an average F-measure of 0.8852. Combination 3 was the AlexNet model and reservoir sampling. It had an average F-measure of 0.8545. Combination 2 was the DenseNet model and sampling with replacement, achieving an average F-measure of 0.8017. Finally, combination 4 was the DenseNet model and reservoir sampling. It had an average F-measure of 0.8111. Overall, we conclude that both models trained on a sampled dataset gave equal or better results compared to the base models, which used the whole dataset.     

Agent-based time delay margin in consensus of multi-agent systems by an event-triggered control method: Concept and computation

This paper deals with defining the concept of agent-based time delay margin and computing its value in multi-agent systems controlled by event-triggered based controllers. The agent-based time delay margin specifying the time delay tolerance of each agent for ensuring consensus in event-triggered controlled multi-agent systems can be considered as complementary for the concept of (network) time delay margin, which has been previously introduced in some literature. In this paper, an event-triggered control method for achieving consensus in multi-agent systems with time delay is considered. It is shown that the Zeno behavior is excluded by applying this method. Then, in a multi-agent system controlled by the considered event-triggered method, the concept of agent-based time delay margin in the presence of a fixed network delay is defined. Moreover, an algorithm for computing the value of the time delay margin for each agent is proposed. Numerical simulation results are also provided to verify the obtained theoretical results.     

Detection of Abnormal Activities from Various Signals Based on Statistical Analysis

We perceive big data with massive datasets of complex and variegated structures in the modern era. Such attributes formulate hindrances while analyzing and storing the data to generate apt aftermaths. Privacy and security are the colossal perturb in the domain space of extensive data analysis. In this paper, our foremost priority is the computing technologies that focus on big data, IoT (Internet of Things), Cloud Computing, Blockchain, and fog computing. Among these, Cloud Computing follows the role of providing on-demand services to their customers by optimizing the cost factor. AWS, Azure, Google Cloud are the major cloud providers today. Fog computing offers new insights into the extension of cloud computing systems by procuring services to the edges of the network. In collaboration with multiple technologies, the Internet of Things takes this into effect, which solves the labyrinth of dealing with advanced services considering its significance in varied application domains. The Blockchain is a dataset that entertains many applications ranging from the fields of crypto-currency to smart contracts. The prospect of this research paper is to present the critical analysis and review it under the umbrella of existing extensive data systems. In this paper, we attend to critics' reviews and address the existing threats to the security of extensive data systems. Moreover, we scrutinize the security attacks on computing systems based upon Cloud, Blockchain, IoT, and fog. This paper lucidly illustrates the different threat behaviour and their impacts on complementary computational technologies. The authors have mooted a precise analysis of cloud-based technologies and discussed their defense mechanism and the security issues of mobile healthcare.

     

Investigations on mode-division multiplexed free-space optical transmission for inter-satellite communication link

Wireless Networks - Inter-satellite data transmission links are very crucial for providing global inter-connectivity. We report designing and investigations on high date rate inter-satellite...     

Investigating the effect of varying block size on power and energy consumption of GPU kernels

The Journal of Supercomputing - Power consumption is likely to remain a significant concern for exascale performance in the foreseeable future. In addition, graphics processing units (GPUs) have...