19672 research outputs found
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Path Loss Model for Outdoor Parking Environments at 28 GHz and 38 GHz for 5G Wireless Networks
No full textIt has been widely speculated that the performance of the next generation Internet of Things (IoT) based wireless network should meet a transmission speed on the order of 1000 times more than current wireless networks; energy consumption on the order of 10 times less and access delay of less than 1 ns that will be provided by future 5G systems. To increase the current mobile broadband capacity in future 5G systems, the millimeter wave (mmWave) band will be used with huge amounts of bandwidth available in this band. Hence, to support this wider bandwith at the mmWave band, new radio access technology (RAT) should be provided for 5G systems. The new RAT with symmetry design for downlink and uplink should support different scenarios such as device to device (D2D) and multi-hop communications. This paper presents the path loss models in parking lot environment which represents the multi-end users for future 5G applications. To completely assess the typical performance of 5G wireless network systems across these different frequency bands, it is necessary to develop path loss (PL) models across these wide frequency ranges. The short wavelength of the highest frequency bands provides many scatterings from different objects. Cars and other objects are some examples of scatterings, which represent a critical issue at millimeter-wave bands. This paper presents the large-scale propagation characteristics for millimeter-wave in a parking lot environment. A new physical-based path loss model for parking lots is proposed. The path loss was investigated based on different models. The measurement was conducted at 28 GHz and 38 GHz frequencies for different scenarios. Results showed that the path loss exponent values were approximately identical at 28 GHz and 38 GHz for different scenarios of parking lots. It was found that the proposed compensation factor varied between 10.6 dB and 23.1 dB and between 13.1 and 19.1 in 28 GHz and 38 GHz, respectively. The proposed path loss models showed that more compensation factors are required for more scattering objects, especially at 28 GHz
50 days of war on innocent civilian: Ma’an news agency coverage of Israeli and Palestinian conflict
No full textSince the TV broadcasting was established in Arab countries until the 1990s, broadcasting during this specific time was based on a government control model, which derived from the view of broadcasting as an instrument of state advance that must be under the control from government. This kind of TVs, limits the broadcasting to highlight the government issue (1). In these kind of TVs, they focus with the leader's opinion more than the Palestinian problem. By the way, the theme in Arab media determined to highlight the leader's opinion who claims the right to speak on behalf of Palestinians. In September 1991, the first private TV in the Arab world was established when MBC went on the air from London. More private TVs followed after that like: Orbit in 1994 and ART in 1995, both based in Italy owned by Saudi businessmen, Future Television and LBC, both Lebanese based in Beirut, in 1995, and Al-Jazeera based in Qatar in 1996. In 2002 the number of the Arab TV stations was expanded to more than 150 TVS as government or privately owned, with capability of reaching the Arab people in any place in the world. This paper focuses on the media coverage of the conflict between two parties Palestine and Israel. The preview studies show that, in a conflict the media has an influential role and has responsibility for increasing violence or contributing to the resolution of conflict and mitigation of violence (2). This study examined 61 news coverage and framing of the Israel and Palestine conflict, known as the 50 days' war from 8 July - 26 August 2014 by Ma'an News Agency, which delivers news to Ma'an TV (Palestinian satellite television station). A quantitative content analysis was employed to examine the news published during the war using five generic frames developed by (3). Holsti Inter-coder reliability and validity test value is 0.988 or 98% agreement. The results showed that conflict and human-interest frames were significantly visible compared to other frames in Ma'an news coverage. Portrayal of images of civilian killing, children and women killed in their homes and suffrage news coverage, in this war. Responsibility frame stressed on hospitals bombing and embargo of medications which reduced chances for Palestinian of immediate medical help. The economic frame highlighted the economic and financial losses of Palestinians as consequences of 50 days' war. Most of them lost their income, businesses, agriculture land and homes and became refugees
Chemical profiling and biological activity of Peperomia blanda (Jacq.) Kunth
No full textBackground. Peperomia belongs to the family of Piperaceae. It has different uses in folk medicine and contains rare compounds that have led to increased interest in this genus. Peperomia blanda (Jacq.) Kunth is used as an injury disinfectant by Yemeni people. In addition, the majority of Yemen's population still depend on the traditional remedy for serious diseases such as cancer, inflammation and infection. Currently, there is a deficiency of scientific evidence with regards to the medicinal plants from Yemen. Therefore, this study was performed to assess the chemical profile and in vitro antioxidant and cytotoxic activities of P. blanda. Methods. Chemical profiling of P. blanda was carried out using gas chromatography mass spectrometry (GCMS) followed by isolation of bioactive compounds by column chromatography. DPPH• and FRAP assays were used to evaluate antioxidant activity and the MTT assay was performed to estimate the cytotoxicity activity against three cancer cell lines, namely MCF-7, HL-60 and WEHI-3, and three normal cell lines, MCF10A, WRL-68 and HDFa. Results. X-ray crystallographic data for peperomin A is reported for the first time here and N, N0-diphenethyloxamide was isolated for the first time from Peperomia blanda. Methanol and dichloromethane extracts showed high radical scavenging activity with an IC50 of 36.81 ± 0.09 μg/mL, followed by the dichloromethane extract at 61.78 ± 0.02 μg/mL, whereas the weak ferric reducing activity of P. blanda extracts ranging from 162.2 ± 0.80 to 381.5 ± 1.31 μg/mL were recorded. In addition, petroleum ether crude extract exhibited the highest cytotoxic activity against all the tested cancer cell lines with IC50 values of 9.54 ± 0.30, 4.30 ± 0.90 and 5.39 ± 0.34 μg/mL, respectively. Peperomin A and the isolated mixture of phytosterol (stigmasterol and β-sitosterol) exhibited cytotoxic activity against MCF-7 and WE-HI cell lines with an IC50 of (5.58 ± 0.47, 4.62 ± 0.03 μg/mL) and (8.94 ± 0.05, 9.84 ± 0.61 μg/mL), respectively, compared to a standard drug, taxol, that has IC50 values of 3.56 ± 0.34 and 1.90 ± 0.9 μg/mL, respectively. Conclusion. The activities of P. blanda extracts and isolated compounds recorded in this study underlines the potential that makes this plant a valuable source for further study on anticancer and antioxidant activities
Analysis of Online Social Network Connections for Identification of Influential Users
No full textOnline social networks (OSNs) are structures that help users to interact, exchange, and propagate new ideas. The identification of the influential users in OSNs is a significant process for accelerating the propagation of information that includes marketing applications or hindering the dissemination of unwanted contents, such as viruses, negative online behaviors, and rumors. This article presents a detailed survey of influential users’ identification algorithms and their performance evaluation approaches in OSNs. The survey covers recent techniques, applications, and open research issues on analysis of OSN connections for identification of influential users
Path loss model for indoor emergency stairwell environment at millimeter wave band for 5G network
No full textThe unused millimeter-wave (mmWave) spectrum offers a superb opportunity to increase mobile broadband capacity due to the enormous amount of available bandwidth. Different candidate operating frequencies for 5G wireless networks are available at the mmWave band. For 5G wireless networks, the emergency case is one of the applications. This paper presents the outcome of indoor emergency stairwell measurement campaigns for 5G system at 26 GHz, 28 GHz, 32 GHz, and 38 GHz, which were conducted at the University Technology Malaysia, Kuala Lumpur, Malaysia. To effectively evaluate the performance of 5G wireless systems in these different bands, single- and multifrequency path loss models are proposed for this environment. This paper proposes a new path loss model based on a new physical anchor point referred to as physical-anchor stair (PAS) path loss model. In a single-frequency large-scale case study, the PAS and the floating intercept (FI) path loss model are investigated at the 20 GHz and 30 GHz bands. Moreover, this study is extended to cover the multifrequency path such as the alpha, beta, and gamma model and the close-in free space path loss model with frequency weight (CIF) model. The CIF model is developed in this paper. The proposed PAS model shows high accuracy (physically based model) and less complexity compared with the studied models. Results show that the path loss exponent values vary between 6.6 and 7.9 for all measured frequencies using the proposed PAS model and between 9.1 and 10.9 using the FI model
Detection of mutated Plasmodium vivax Kelch propeller domain (PvK12) in Malaysian isolates
No full textMalaysia is located near the borders of countries where artemisinin resistant Plasmodium falciparum (mutations in the P. falciparum Kelch propeller domain [PfK13]) have been reported. Plasmodium vivax Kelch propeller domain, PvK12, the ortholog of PfK13, could assess resistance towards artemisinin in vivax malaria. Polymorphisms in PvK12 gene were determined by PCR and sequencing was done in 300 clinical isolates collected in recent years (2012–2017) from hospitals within the country. Among 48 P. vivax samples, all were Sal-1 wild type alleles except for two isolates, a synonymous and nonsynonymous mutation respectively. The nonsynonymous (V552I) isolate was collected from an immigrant. P. vivax with mutated PvK12 is speculated to be an imported case and is likely to be circulating at very low frequency in Malaysia. An in-depth drug resistance surveillance among immigrants needs to be investigated to provide information that may be crucial for drug policy changes
Polyaniline modified magnetic nanoparticles coated with dicationic ionic liquid for effective removal of rhodamine B (RB) from aqueous solution
No full textPolyaniline (PANI) modified magnetic nanoparticle (MNP) nanocomposites coated with newly synthesized dicationic ionic liquid (DICAT) forming MNP-PANI-DICAT were successfully synthesized as a potential material for the removal of Rhodamine B (RB) from water samples. The synthesized material was successfully characterized using a few techniques such as Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), thermo gravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), and transmission electron microscopy (TEM) analysis. Several parameters have been optimized to enhance the efficiency of the removal process. The adsorption kinetics were investigated and the results showed that MNP-PANI-DICAT was best fitted to a pseudo-second order model for the adsorption of RB. As for the isotherm studies, Temkin's model was found to fit well with the adsorption isotherm of RB on MNP-PANI-DICAT. Other than that, thermodynamics results showed negative values of ΔG° for the adsorption of RB, which indicated that the process is thermodynamically feasible, spontaneous and chemically controlled at lower temperature. The negative value of enthalpy ΔH° (−40.41) indicated that the adsorption was an exothermic process. The percentage removal of RB was found to be 94.7% by MNP-PANI-DICAT under optimized conditions
Maximum Power Point Tracking for Photovoltaic Systems under Partial Shading Conditions Using Bat Algorithm
No full textThe vibrant, noiseless, and low-maintenance characteristics of photovoltaic (PV) systems make them one of the fast-growing technologies in the modern era. This on-demand source of energy suffers from low-output efficiency compared with other alternatives. Given that PV systems must be installed in outdoor spaces, their efficiency is significantly affected by the inevitable complication called partial shading (PS). Partial shading occurs when different sections of the solar array are subjected to different levels of solar irradiance, which then leads to a multiple-peak function in the output characteristics of the system. Conventional tracking techniques, along with some nascent/novel approaches used for the tracking maximum power point (MPP), are unsatisfactory when subjected to PS, eventually leading to the reduced efficiency of the PV system. This study aims at investigating the use of the bat algorithm (BA), a nature-inspired metaheuristic algorithm for MPP tracking (MPPT) subjected to PS conditions. A brief explanation of the behavior of the PV system under the PS condition and the advantages of using BA for estimating the MPPT of the PV system under PS condition is discussed. The deployment of the BA for the MPPT in PV systems is then explained in detail highlighting the simulation results which verifies whether the proposed method is faster, more efficient, sustainable and more reliable than conventional and other soft computing-based methods. Three testing conditions are considered in the simulation, and the results indicate that the proposed technique has high efficiency and reliability even when subjected to an acute shading condition
Major trends in device to device communications research: A bibliometric analysis
Get PDFThe quantitative study of bibliographic material is referred to as bibliometric analysis. It presents a general overview of a research area where the published works can be classified based on countries, authors, publication years,
keywords, and fields of research. This study aims to provide a bibliometric analysis of the research carried out in the field of device to device (D2D) communications in the past decade. The primary objective of this study is to find some of the most relevant and influential research papers in this field and define the newest trends as per the information available in the Web of Science database. During the course of this study, numerous classifications have been made based on different parameters such as the most productive and influential authors, and the most influential keywords and journals. The conclusions of this study are in line with the common wisdom, although certain deviations have been found
Myofibroblastoma of the breast
No full textIntroduction: Myofibroblastoma is a rare benign mesenchymal tumour arising from the stromal elements of the breast tissue. Histopathological variants such as classic, cellular, collagenous / fibrous, lipomatous, infiltrative, myxoid and epithelioid have been identified. Most myofibroblastomas are immunoreactive for CD34, actin, CD10 and desmin, usually express oestrogen receptor (ER), progesterone receptor (PR) and variably express androgen receptor (AR). Case report: We report a case of myofibroblastoma in an octogenarian male presenting with painless solitary breast lump. Mammography (digital tomosynthesis) and ultrasound showed a well-circumscribed hyperdense mass and hypoechoic, solid, oval mass with peripheral vascularity respectively. Patient underwent wide local excision. Discussion: Diverse characteristics of myofibroblastoma on imaging necessitates histopathological analysis for an accurate diagnosis. Myofibroblastoma are often confused with fibroadenomas due to the benign imaging characteristics and with malignant neoplasia due to their wide morphological spectrum. Surgical excision is considered curative