A Survey and Comparison of Device-to-Device Architecture Using LTE Unlicensed Band

© 2017 IEEE. Due to the rapid increase in data traffic, one of the solutions provided by mobile operators is to operate Long Term Evolution (LTE) in the unlicensed 5GHz band, as the licensed spectrum is becoming scarce. Mobile operators can expand their network capacity by operating LTE in the unlicensed band at lower cost when compared with using other licensed bands. Device to Device (D2D) communication, proven to be another effective way to enhance the capacity of a network, enables direct data exchange of localized traffic of users in proximity. Applying D2D communication to LTE unlicensed 5GHz band will further improve the network performance and user experience. In this article, we will discuss the new type of solutions that have been proposed for LTE operating in an unlicensed 5GHz band that includes; LTE-Unlicensed (LTE-U), LTE-License Assisted Access (LTE-LAA), LTE WiFi Link Aggregation (LWA), and MuLTEfire. We will discuss the important features along with their advantages and disadvantages and compare these technologies as well. We simulate LTE-LAA, LWA and MuLTEfire technologies in the presence of Wi-Fi hotspot and compare their results. Furthermore, we apply D2D communication to these technologies and from the results we conclude that MuLTEfire can increase the throughput drastically but network saturates quickly. Whereas, applying D2D communication with LWA is beneficial for a scalable network as it will not only increase the network throughput but will increase the network capacity as well

A simulation-based study to calculate all the possible trajectories of differential drive mobile robot

Deferential Drive Mobile Robot (DDMR) is being used in many applications as it is easy to be modeled and controlled. This research presents the idea of using DDMR turning motion behavior to develop an algorithm that calculate all the circular trajectories. This can be used to navigate DDMR in a curvature paths instead of linear ones. In this research we design and simulate Differential Drive Mobile Robot (DDMR) model. Then we use the simulated model to calculate all the possible trajectories that DDMR can follow with each left and right wheel velocity configurations. Results are saved in a navigation look-up table that can be implemented in DDMR navigation's approach. © 2021 Author(s)

Rotating range sensor approached for mobile robot obstacle detection and collision avoidance applications

Range finder sensors are widely used in the obstacle detection and collision avoidance applications. In this research, we propose rotating range finder sensor that provides economic and efficient solution for mobile robot applications. Rotating approach is achieved by coupling the range sensors with servomotor. In this article, rotating approach model design, main parameters, equations and limitation are described. In addition, an algorithm is developed to control the rotation angle of the range sensor, extract data from the approach and analyze it. A case study of the rotating approach by implementing ultrasonic sensor is simulated and the results are obtained. Simulation platform Gazebo and ROS are used to simulate the rotating approach. © 2021 Author(s)

African vulture optimizer algorithm based vector control induction motor drive system

This study describes a new optimization approach for three-phase induction motor speed drive to minimize the integral square error for speed controller and improve the dynamic speed performance. The new proposed algorithm, African vulture optimizer algorithm (AVOA) optimizes internal controller parameters of a fuzzy like proportional differential (PD) speed controller. The AVOA is notable for its ease of implementation, minimal number of design parameters, high convergence speed, and low computing burden. This study compares fuzzy-like PD speed controllers optimized with AVOA to adaptive fuzzy logic speed regulators, fuzzy-like PD optimized with genetic algorithm (GA), and proportional integral (PI) speed regulators optimized with AVOA to provide speed control for an induction motor drive system. The drive system is simulated using MATLAB/Simulink and laboratory prototype is implemented using DSP-DS1104 board. The results demonstrate that the suggested fuzzy-like PD speed controller optimized with AVOA, with a speed steady state error performance of 0.5% compared to the adaptive fuzzy logic speed regulator’s 0.7%, is the optimum alternative for speed controller. The results clarify the effectiveness of the controllers based on fuzzy like PD speed controller optimized with AVOA for each performance index as it provides lower overshoot, lowers rising time, and high dynamic response

Experimental Investigation of the Performance and Exhaust Emissions of a Spark-Ignition Engine Operating with Different Proportional Blends of Gasoline and Water Ammonia Solution

This paper aims to investigate the impact of water ammonia solution (WAS)-gasoline fuel (GF) blends on SI engine exhaust emission and engine performance characteristics and compare the obtained results with those using base gasoline. This investigation used a single-cylinder, four-stroke, air-cooled, and SI engine coupled with an AC generator to achieve this experimental work. Water ammonia solution fuel was blended with neat gasoline in volume rates of 5, 10,15,20, and 25%. The experimental investigation was conducted at an off-road engine under a constant engine speed of 3000 rpm and different load conditions. The results show that the use of ammonia solution as an addition to gasoline fuel increase the overall thermal efficiency, and G75Was25 blend obtained the maximum increase ratio of overall efficiency by 38.96% at maximum load condition in comparison to neat gasoline and reduce the specific fuel consumption compared with that of gasoline fuel. This alteration results in an elevation in CO, HC, and NOx emissions

Non-invasive index of liver fibrosis induced by alcohol, thioacetamide and schistosomal infection in mice

<p>Abstract</p> <p>Background</p> <p>Non invasive approaches will likely be increasing utilized to assess liver fibrosis. This work provides a new non invasive index to predict liver fibrosis induced in mice.</p> <p>Methods</p> <p>Fibrosis was generated by thioacetamide (TAA), chronic intake of ethanol, or infection with <it>S. mansoni </it>in 240 mice. Both progression and regression of fibrosis (after treatment with silymarin and/or praziquantel) were monitored. The following methods were employed: (i) The METAVIR system was utilized to grade and stage liver inflammation and fibosis; (ii) Determination of hepatic hydroxyproline and collagen; and (iii) Derivation of a new hepatic fibrosis index from the induced changes, and its prospective validation in a group of 70 mice.</p> <p>Results</p> <p>The index is composed of 4 serum variable including total proteins, γ-GT, bilirubin and reduced glutathione (GSH), measured in diseased, treated and normal mice. These parameters were highly correlated with both the histological stage and the grade. They were combined in a logarithmic formula, which non-invasively scores the severity of liver fibrosis through a range (0 to 2), starting with healthy liver (corresponding to stage 0) to advanced fibrosis (corresponding stage 3).Receiver operating characteristic curves (ROC) for the accuracy of the index to predict the histological stages demonstrated that the areas under the curve (AUC) were 0.954, 0.979 and 0.99 for index values corresponding to histological stages 1, 2 and 3, respectively. Also, the index was correlated with stage and grade, (0.947 and 0.859, respectively). The cut off values that cover the range between stages 0-1, 1-2 and 2-3 are 0.4, 1.12 and 1.79, respectively. The results in the validation group confirmed the accuracy of the test. The AUROC was 0.869 and there was good correlation with the stage of fibrosis and grade of inflammation.</p> <p>Conclusion</p> <p>The index fulfils the basic criteria of non-invasive marker of liver fibrosis since it is liver-specific, easy to implement, reliable, and inexpensive. It proved to be accurate in discriminating precirrhotic stages.</p

Challenges in Learning to Speak Arabic

This paper describes a study to investigate the challenges and obstacles to speaking Arabic faced by good and poor Malay speakers of Arabic. The study used individual and focus group interviews with 14 participants to elicit data. The findings revealed 2 types of obstacles, namely, internal and external obstacles. Internal obstacles refer to the limitations that come from the learners’ own selves, knowledge and skills; while external obstacles refer to the constraints that originate from the outside, such as the lack of a supportive environment and sufficient opportunity to speak Arabic. Both good and poor Malay speakers of Arabic felt hampered more by the internal problems than by the external problems. However, it was noted that the good speakers faced more language-related problems than other internal issues, while the poor speakers   revealed more internal shortcomings such as lack of confidence and self-esteem. Keywords: Arabic language, language learning strategy, problems in learning speaking skills, speaking skills

Antibiotic Therapy and the Gut Microbiome:Investigating the Effect of Delivery Route on Gut Pathogens

The contribution of the gut microbiome to human health has long been established, with normal gut microbiota conferring protection against invasive pathogens. Antibiotics can disrupt the microbial balance of the gut, resulting in disease and the development of antimicrobial resistance. The effect of antibiotic administration route on gut dysbiosis remains under-studied to date, with conflicting evidence on the differential effects of oral and parenteral delivery. We have profiled the rat gut microbiome following treatment with commonly prescribed antibiotics (amoxicillin and levofloxacin), via either oral or intravenous administration. Fecal pellets were collected over a 13-day period and bacterial populations were analyzed by 16S rRNA gene sequencing. Significant dysbiosis was observed in all treatment groups, regardless of administration route. More profound dysbiotic effects were observed following amoxicillin treatment than those with levofloxacin, with population richness and diversity significantly reduced, regardless of delivery route. The effect on specific taxonomic groups was assessed, revealing significant disruption following treatment with both antibiotics. Enrichment of a number of groups containing known gut pathogens was observed, in particular, with amoxicillin, such as the family Enterobacteriaceae. Depletion of other commensal groups was also observed. The degree of dysbiosis was significantly reduced toward the end of the sampling period, as bacterial populations began to return to pretreatment composition. Richness and diversity levels appeared to return to pretreatment levels more quickly in intravenous groups, suggesting convenient parenteral delivery systems may have a role to play in reducing longer term gut dysbiosis in the treatment of infection