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A new compact printed monopole antenna is presented in this paper. An open-loop hexagonal radiator excited by a microstrip feed line, which is printed on top of the substrate, which is FR4 type, while on another side, a partial ground plane is fixed and embedded with two pairs of slits as well as a pair of rectangular strips. Triple operating bands with two different polarization types are obtained. The lower band has right-hand circular polarization (RHCP) characteristic, whereas the upper band has left-hand circular polarization (LHCP) characteristic means that a dual-band dual-sense circular polarization (CP). Concerning the middle band, a linear polarization (LP) has been gotten in this antenna. Numerical analysis and experimental validation of the proposed antenna structure have been performed, and results are demonstrated. The measured impedance bandwidths (IBWs) are 14.7% (1.478-1.714 GHz), 6.8% (2.54-2.72 GHz), and 13.1% (4.29-4.89 GHz), respectively. The measured 3-dB axial ratio bandwidths (ARBWs) are 6.2% (1.510-1.606 GHz), and 22.7% (4.035-5.07 GHz) for the lower and the upper band, respectively. So, it's suitable for covering modern wireless applications such as GPS (Global Positioning System), LTE (Long Term Evaluation), and Satellite.

With the rise of satellite mega-constellations, high-data-rate and low-latency space-based internet is set to transform the lives of users in remote locations with no access to the fiber-optic infrastructure. While current commercial constellations are relying on microwaves, they are legally and technologically limited to only a few gigahertz of bandwidth, paralyzing the potential for ultra high data rate performance. In this paper, a dual terahertz/Ka-band communication system is proposed and studied as a solution. A space-Earth propagation model based on the International Telecommunication Union most recent recommendations is presented, and a mega-constellation of 8,320 small satellites in low Earth orbit is designed to test the dual-band performance for the uplink, downlink, and crosslink. Extensive simulations are performed using an in-house-developed orbital simulation tool to calculate data rates for each terahertz and Ka band links based on signal-to-noise ratio estimates with dynamic decision making to constantly provide the highest data rate possible. For links between Earth and space, the results show similar performance for terahertz and Ka-band communications, while terahertz significantly outperforms in inter-satellite links. Simulation results show that terahertz communication can be a good candidate for space-Earth and inter-satellite links as both an enhancement to existing microwave technology and as a stand-alone technology with the identified challenges addressed.

Blockchain is a decentralized database that stores a growing chain of blocks formed and secured by the consensus of a network node. Blockchain technology is a solution to applications and smart programs so that no third party (peer-to-peer network) is required to store and verify transactions in a safe and reliable manner, such as cryptocurrencies, smart contracts, health care, and the Internet of things (IoT). However, this technology suffers from some limitations, such as network latency and slow transaction validation. In this paper, the proposed method is implemented and discussed by improving the topology of the peer-to-peer blockchain structure to a decentralized topology (structured topology in clusters). This aims to speed up transactions broadcasting time, as well as to reduce the enormous time for nodes consensus mechanism to validate transactions through the intra- and inter-cluster parallel mining in the Proof of Work (PoW) mechanism. The test results demonstrate the feasibility of the proposed method in reducing the consensus time, as well as improve the scalability of the network.

International audience; Latency-sensitive fog computing applications may use replication both to scale their capacity and to place application instances as close as possible to their end users. In such geo-distributed environments, a good replica placement should maintain the tail network latency between end-user devices and their closest replica within acceptable bounds while avoiding overloaded replicas. When facing non-stationary workloads it is essential to dynamically adjust the number and locations of a fog application's replicas. We propose Voilà, a tail-latency-aware auto-scaler integrated in the Kubernetes orchestration system. Voilà maintains a fine-grained view of the volumes of traffic generated from different user locations, and uses simple yet highly-effective procedures to maintain suitable application resources in terms of size and location.

A miniature planar microstrip antenna of bowtie shape with four frequency bands have been rejected to avoid interfering with several services operating within these bands. A quarter wavelength transformer is introduced for matching purposes. The bowtie right side has a horizontal slit to enhance the bandwidth and it is connected to the microstrip feed line, while its left side is connected to the partial ground plane in the back side through a shorting pin. The simulated Reflection Coefficient $S_{11}$ has a 10-dB range from 2.69 to 15.06 GHz with rejection bands of (3.39 - 4.23) GHz, (4.64 - 6.07) GHz, (6.82 - 8.94) GHz and (9.75 - 12.19) GHz. The proposed antenna can achieve a maximum gain of 5.79 dB.

Diabetic retinopathy (DR) is a progressive eye disease that affects a large portion of working-age adults. DR, which may progress to an irreversible state that causes blindness, can be diagnosed with a comprehensive dilated eye exam. With the eye dilated, the Doctor takes pictures of the inside of the eye via a medical procedure called Fluorescein Angiography, in which a dye is injected into the bloodstream. The dye highlights the blood vessels in the back of the eye so they can be photographed. In addition, the Doctor may request an Optical Coherence Tomography (OCT) exam, by which cross-sectional photos of the retina are produced to measure the thickness of the retina. Early prognostication is vital in treating the disease and preventing it from progressing into advanced irreversible stages. Skilled medical personnel and necessary medical facilities are required to detect DR in its five major stages. In this paper, we propose a diagnostic tool to detect Diabetic retinopathy from fundus images by using an ensemble of multi-inception CNN networks. Our inception block consists of three Convolutional layers with kernel sizes of 3x3, 5x5, and 1x1 that are concatenated deeply and forwarded to the max-pooling layer. We experimentally compare our proposed method with two pre-trained models: VGG16 and GoogleNets. The experiment results show that the proposed method can achieve an accuracy of 93.2% by an ensemble of 10 random networks, compared to 81% obtained with transfer learning based on VGG19.

Generating smooth surfaces of arbitrary topology is a major challenge in geometric modeling, computer graphics, and scientific visualization. Subdivision surfaces have emerged as a powerful and useful technique in modeling free-form surfaces. Recursive subdivision techniques generate visually pleasing smooth surfaces through the repeated application of a fixed set of subdivision rules. Given a control mesh, a Catmull-Clark Subdivision Surface (CCSS) is generated by iteratively refining (subdividing) the control mesh to form new control meshes. CCSS implementations do not perform well and suffer from low CPU utilization because they are often waiting for data to be transferred from memory due to the repeated pointer indirections. Rapid Evaluation of CCSS is an approach that focuses on achieving maximum performance by carefully addressing caching issues. However, this approach is designed with primary target being single core machines. In this paper, we implement the Rapid Evaluation of Catmull-Clark Subdivision Surfaces (RECCSS) algorithm in C++ and measure its achieved performance. We then redesign RECCSS to leverage the potential of parallel computation on widely available multicores machines and show that Parallelized RECCSS (PRECCSS) achieves noticeable speedup when run on diverse set of machines compared to the original RECCSS implementation. In addition, we conduct a study about the data value predictability of PRECCSS load instructions using Pin dynamic binary instrumentation tool, and conclude that 93.25% prediction accuracy can be achieved with existing value prediction techniques.

Wi-Fi connectivity, a necessity in this digital era, requires careful infrastructure planning and tuning during installation. In this paper, we propose “Aparecium Wi-Fi Planner”, an open-source and cross-platform, Wi-Fi planning software tool based on an enhanced empirical path loss model. The proposed “Enhanced Solah's model” delivers more accurate results than existing models. And hence, “Aparecium Wi-Fi Planner” accurately estimates path loss attenuation, absorption attenuation by obstacles and fading effect. Moreover, the tool integrates the design and development of several algorithms to find full-coverage and optimal access point location with reduced complexity. Aparecium has been thoroughly tested and validated using both simulation and real testbed scenarios.

A miniature planar meandered microstrip bowtie-shaped antenna has been proposed for wireless applications. The designed antenna can serve many applications through its multiband characterization and as a UWB with six rejection bands since it covers the UWB licensed range. The antenna is designed on FR4-substrate and fed by a 50 Ω microstrip feed line connected to the right portion of the bowtie. The left side of the bowtie is connected to the partial ground at the bottom layer through a shorting pin. Both sides of the bowtie have a gradually increased zigzag microstrip line optimized to enhance the notches and the resonant frequencies. The proposed antenna is investigated using the high-frequency structure simulator (HFSS). The simulated reflection coefficient S 11 result shows bandwidth ranges from 2.55 to 10.94 GHz at return loss (RL = |S 11 |) ≥ 10 dB with rejected frequency bands of (2.66 – 4) GHz, (4.25 – 4.94) GHz, (5.08 – 5.91) GHz, (6.6 – 6.96) GHz, (7.25 – 7.7) GHz and (8 – 9.57) GHz. The proposed antenna can achieve a maximum gain of 4.42 dB. The antenna radiation patterns exhibit a directional in E-plane and an omnidirectional shape in H-plane at lower frequencies.

A compact planar microstrip bowtie-shaped antenna has been designed for UWB wireless applications. The designed antenna has been optimized to reject three frequency bands to avoid interference with the applications utilized in these bands. The antenna is designed on 1.6 mm thick FR4-substrate and fed by 50 Ω microstrip feed line. Two quarter wavelength transformers are introduced to enhance the impedance matching. The bowtie right side has a horizontal slit to enhance the bandwidth and it is connected to the microstrip feed line, while its left side is composed of a parasitic of bowtie shaped and a microstrip line connected to the partial ground plane in the back side through a shorting pin. The proposed antenna is investigated using the high-frequency structure simulator (HFSS). The simulated scattering parameter S 11 (Reflection Coefficient) result shows bandwidth ranges from 1.95 to 12.92 GHz at return loss (RL = |S 11 |) ≥ 10 dB with rejection bands of (2.13 – 3.96) GHz, (4.42 – 5.53) GHz and (7.51 – 9.3) GHz. The proposed antenna can achieve a maximum gain of 5.85 dB. The patterns exhibit an omnidirectional shape at lower frequencies.

In this paper, a new planar bowtie-shaped antenna has been proposed for UWB wireless applications. The antenna is designed on FR4-substrate and fed by 50 Ω microstrip feed line with two quarter wavelength transformers for better impedance matching. The bowtie right side has a horizontal slit to enhance the bandwidth and it is connected to the microstrip feed line, while its left side is connected to the partial ground plane in the back side through shorting pin. The proposed antenna is investigated using the high-frequency structure simulator (HFSS). The simulated scattering parameter S 11 (Reflection Coefficient) result shows bandwidth ranges from 3.05 to 10.8 GHz at return loss (RL = |S 11 |) ≥ 10 dB. The proposed antenna has high gain value, omnidirectional radiation pattern in the H-plane and mushroom-Shaped in the E-plane at lower frequency edge are achieved.