Study the Characteristic of Planer and Sandwich PSi Gas Sensor (Comparative Study)

In this work, two configurations (planner and sandwich) structures of (Al/n PSi/n-Si/Al) porous silicon (PSi) gas sensor have been fabricated and tested extensively for CO₂ gas molecules. Two laser wavelength infrared and violet of (810 nm) and (405 nm) was used in the laser assisting etching process on the n-type silicon substrate. The gas detection characteristic of planner and sandwich configuration were studied under different condition. The resistance measurement, for the planner and J-V characteristic for sandwich structures, which was analyzed based on the nano-sized silicon, porosity, layer thickness, and the effective dielectric constant of the PSi layer. The SEM image of the PSi layer showed the formation pore-like structure with cylindrical and rectangular pore shape with different dimensions for infrared illuminated PSi and crossed pores-like structure with randomly distributed for violet illuminated PSi. The sensing mechanism for sandwich structure configuration is governed by the porous silicon parameters, while for planer configuration the silicon channel among the pore has a significant role in sensing process.     

Prediction-based secured handover authentication for mobile cloud computing

Mobile cloud computing (MCC) is a new technology that brings cloud computing and mobile networks together. It enhances the quality of service delivered to mobile clients, network operators, and cloud providers. Security in MCC technology, particularly authentication during the handover process, is a big challenge. Current vertical handover authentication protocols encounter different problems such as undesirable delays in real-time applications, the man in the middle attack, and replay attack. In this paper, a new authentication protocol for heterogeneous IEEE 802.11/LTE-A mobile cloud networks are proposed. The proposed protocol is mainly based on the view of the 3GPP access network discovery and selection function, which uses the capacities given by the IEEE 802.11 and the 3GPP long term evolution-advanced (LTE-A) standards interconnection. A prediction scheme, with no additional load over the network, or the user is utilized to handle cloud computing issues arising during authentication in the handover process. The proposed handover authentication protocol outperformed existing protocols in terms of key confidentiality, powerful security, and efficiency which was used to reduce bandwidth consumption.

     

An Optimized Collaborative Scheduling Algorithm for Prioritized Tasks with Shared Resources in Mobile-Edge and Cloud Computing Systems

Mobile edge computing (MEC) is a promising technology that has the potential to meet the latency requirements of next-generation mobile networks. Since MEC servers have limited resources, an orchestrator utilizes a scheduling algorithm to decide where and when each task should execute so that the quality of service (QoS) of each task is achieved. The scheduling algorithm should use the least possible resources required to meet the service demands. In this paper, we develop a two-level cooperative scheduling algorithm with a centralized orchestrator layer. The first scheduling level is used to schedule tasks locally on MEC servers. In contrast, the second level resides at the orchestrator and assigns tasks to a neighboring base station or the cloud. The tasks serve in accordance with their priority, which is determined by the latency and required throughput. We also present a resource optimization algorithm for determining resource distribution in the system in order to ensure satisfactory service availability at the minimum cost. The resource optimization algorithm contains two variations that can be employed depending on the traffic model. One variant is used when the traffic is uniformly distributed, and the other is used when the traffic load is unbalanced among base stations. Numerical results show that the cooperative model of task scheduling outperforms the non-cooperative model. Furthermore, the results show that the suggested scheduling algorithm performs better than other well-known scheduling algorithms, such as shortest job first scheduling and earliest deadline first scheduling.

     

A broadband hybrid GaN cascode low noise amplifier for WiMax applications

This article reports a Microstrip design for low noise amplifier (LNA) using a packaged commercial GaN‐on‐SiC high electron mobility transistor (HEMT). A cascode configuration with an inter‐stage matching and an independent biasing technique was used. A lumped elements design was first developed, analyzed, and simulated in ADS. Then the design was implemented using microstrip technology and simulated using the momentum EM simulation in ADS. The LNA is easy to fabricate, has a low cost, and can be easily modified for other applications. The proposed GaN LNA showed a gain of 13.5 dB with a noise figure (NF) of 3 dB from 2.8 to 3.8 GHz.     

Outage probability analysis of multi-hop relayed wireless networks over $$\alpha -\mu $$ fading channels

In this paper, we study the end-to-end outage probability performance of Amplify and Forward (AF) and Decode and Forward (DF) multi-hop wireless communication systems operating over independent but not necessarily identical \(\alpha -\mu \) fading channels. To this end, we derive an expression for the moment generating function of the reciprocal of the end-to-end signal-to-noise ratio, and then use this expression to evaluate the end-to-end outage probability of the AF system by numerically inverting the Laplace transform. We also derive an expression for the end-to-end outage probability of the DF system.     

La~(3+) doped LiCo_(0.25)Zn_(0.25)Fe_2O_4 spinel ferrite nanocrystals:Insights on structural,optical and magnetic properties

This paper addresses the manipulation of structural,morphology,optical and magnetic properties of LiCo_(0.25)Zn_(0.25)Fe_2 O_4 ferrite via incorporation of different proportions of La~(3+) at the expense of iron ions using a sol-gel method.The samples were characterized using the X-ray diffraction technique(XRD),Fourier transform infrared(FT-IR) spectroscopy,the energy dispersive X-ray spectra(EDX),inductively coupled plasma optical emission spectroscopy(ICP-OES),high resolution scanning electron microscopy(SEM),Brunauer-Emmett-Teller(BET) surface area analysis,ultraviolet-diffuse reflectance spectroscopy(UV-DRS),and vibrating sample magnetometer(VSM) technique.The Rietveld refinements of the samples indicate that at higher concentrations of La3+,nanostructures with dual phase,i.e.cubic spinel and orthorhombic LaFeO_3 perovskite with space group(Pbnm) appear.Optical studies show that the energy band gap(E_g) of the bare LiCo_(0.25)Zn_(0.25)Fe_2 O_4 ferrite sample(2.18 eV) reaches up to 2.47 eV at x=0.06 and above this concentration,it drops sharply to 2.00 eV.Although the saturation magnetization and the coercivity of LiCo_(0.25)Zn_(0.25)La_xFe_(2-x)O_4 are lower than that of LiCo_(0.25)Zn_(0.25)Fe_2 O_4 NPs.Overall,the superparamagnetic nature and low values of saturation magnetization and coercivity of LiCo_(0.25)Zn_(0.25)La_xFe_(2-x)O_4 NPs are suitable to be applied in transformers core.     

Natural Products of Marine Origin for the Treatment of Colorectal and Pancreatic Cancers: Mechanisms and Potential

Gastrointestinal cancer refers to malignancy of the accessory organs of digestion, and it includes colorectal cancer (CRC) and pancreatic cancer (PC). Worldwide, CRC is the second most common cancer among women and the third most common among men. PC has a poor prognosis and high mortality, with 5-year relative survival of approximately 11.5%. Conventional chemotherapy treatments for these cancers are limited due to severe side effects and the development of drug resistance. Therefore, there is an urgent need to develop new and safe drugs for effective treatment of PC and CRC. Historically, natural sources—plants in particular—have played a dominant role in traditional medicine used to treat a wide spectrum of diseases. In recent decades, marine natural products (MNPs) have shown great potential as drugs, but drug leads for treating various types of cancer, including CRC and PC, are scarce. To date, marine-based drugs have been used against leukemia, metastatic breast cancer, soft tissue sarcoma, and ovarian cancer. In this review, we summarized existing studies describing MNPs that were found to have an effect on CRC and PC, and we discussed the potential mechanisms of action of MNPs as well as future prospects for their use in treating these cancers.     

Performance of dual-hop wireless communication systems over the α–μ fading channels

In this paper, we consider a dual-hop wireless communication system with non-regenerative relay node and we study its performance over the α–μ fading channels. Specifically, we derive a closed-form expression for the moment generating function (MGF) of the harmonic mean of end-to-end signal-to-noise ratio (SNR) assuming the α–μ fading models. We also derive closed-form expressions for the end-to-end outage probability and average bit error rate of coherent modulation techniques. The obtained expressions can be reduced to study the performance of dual-hop communication systems over other fading channel models by using the proper values for the α and μ parameters. Numerical results are provided and conclusion remarks are drawn.     

Privatization of Sanitation and Desalination Projects in Palestine

Abstract

The present problems that are related to water and sanitation in Palestine are many and varied, and the disparity between water supply and demand is growing with time due to the rapid population growth and aridity. Desalination has the potential to supply unlimited quantities of high-quality freshwater to Palestinian Communities. On the other hand, the situation of the sewerage system in the cities is extremely critical, and there are no sewerage systems in the rural areas. There is an urgent need for substantial improvements and extensions to the sewerage systems and treatment plants. The available funds for the Palestinian Water Authority (PWA) and other municipalities to implement wastewater and desalination projects are limited. As a result, it is important to fully explore the use of public-private partnerships that utilize sector resources to finance such projects. The objective of this study is to understand incentives for privatization of water supply and sanitation services, with more emphasis on the households' Affordability and Willingness-to-Pay (AWTP) for improved water and sanitation services. The results show that people in Palestine bear the burden of high water supply and sanitation costs. Privatization of the water and sanitation sector will guarantee sustainable development of these sectors under limited financial resources and dependency on external funds.