Evolutionary Centrality and Maximal Cliques in Mobile Social Networks

This paper introduces an evolutionary approach to enhance the process of finding central nodes in mobile networks. This can provide essential information and important applications in mobile and social networks. This evolutionary approach considers the dynamics of the network and takes into consideration the central nodes from previous time slots. We also study the applicability of maximal cliques algorithms in mobile social networks and how it can be used to find the central nodes based on the discovered maximal cliques. The experimental results are promising and show a significant enhancement in finding the central nodes

The impact of national culture on the adoption of e-tourism in Egyptian tourism companies

Many previous studies shed light on the importance of studying the factors that preclude effective adoption of technology in the tourism industry. Prior studies also affirmed the presence of a relationship between the national culture, the acceptance of technology, and the effective adoption thereof. However, those studies differ in the cultural variables used and in results on their influence on technology adoption. This study used the national culture theory of Hofstede (2010) and the Technology Acceptance Model (Davis, 1989) to measure the impact of national culture and normative beliefs of marketing managers on the adoption of e-tourism. Data analysis was carried out using multiple linear regressions and one-way analysis of variance (ANOVA). The results showed that the culture of uncertainty avoidance had a significant positive impact on perceived ease of use and perceived usefulness. Each of the last two elements also affected the attitudes of marketing managers in tourism companies towards e-tourism and their intention to use it. Also, the results affirmed that long-term orientation culture has no significant impact on the perceived usefulness, ease of use or actual use of e-tourism for Egyptian tourism companies. It however seems to affect quality or/and effective adoption of e-tourism business

The Effect of Operating Conditions on the Performance of a Vacuum Membrane Distillation Unit Using PES Flat Sheet Membrane

The desalination of seawater is considered a promising source of potable water in Egypt. Vacuum Membrane Distillation (VMD) is a new separation technology based on the evaporation of saline water through hydrophobic porous membranes by applying vacuum pressure on the permeate side of the membrane to desalinate brackish or seawater. A lab scale experimental model was constructed and operated using hydrophobic polyethersulfone flat sheet membrane (PES) with effective area of 0.049 m2, pore size 0.2-0.4 µm and thickness 120-160 µm. Salt concentration ranging from 5000 ppm to 35000 ppm aqueous NaCl. Resultant permeate flux was measured for the following operating conditions: feed flow temperature (40-50-60-70 °C), flowrate (1-1.2-1.4-1.6 L/min), and vacuum pressure (0.2-0.3-0.4-0.5 Bar). Results showed an increase in permeate flux due to increased temperature, flow rate and vacuum pressure, while it decreased with the increase in salt concentration. The flux value obtained reached 15 kg/m2.hr at T= 40°C, vacuum pressure= 0.4 bar, TDS= 5000ppm, and flow rate 1 L/min, while it reached 29 kg/m2.hr at  T= 70°C, vacuum pressure= 0.5 bar, TDS= 35,000 ppm, and flow rate 1.6 L/min. Electric power consumed by the system reached 0.612 Kwh at  T=70°C, TDS =5000ppm, vacuum pressure = 0.4 bar, and feed flow rate 1 L/min. Keywords: VMD, desalination, vacuum pressure, hydrophobic membrane

Using 3-D CNNs and Local Blood Flow Information to Segment Cerebral Vasculature

© 2018 IEEE. The variability of the strength (increase or decrease) of the blood flow signals throughout the range of slices of the MRA volume is a big challenge for any segmentation approach because it introduces more inhomogenities to the MRA data and hence less accuracy. In this paper, a novel cerebral blood vessel segmentation framework using Time-Of-Flight Magnetic Resonance Angiography (TOF-MRA) is proposed to handle this challenge. The segmentation framework is based on using three dimensional convolutional neural networks (3D-CNN) to segment the cerebral blood vessels taking into account the variability of blood flow signals throughout the MRA scans. It consists of the following two steps: i) bias field correction to handle intensity inhomogeneity which are caused by magnetic settings, ii)instead of constructing one CNN model for the whole TOF-MRA brain, the TOF-MRA volume is divided into two compartments, above Circle of Willis (CoW) and at and below CoW to account for blood flow signals variability across the MRA volume\u27s slices, then feed these two volumes into the three dimensional convolutional neural networks (3D-CNN). The final segmentation result is the combination of the output of each model. The proposed framework is tested on in-vivo data (30 TOF-MRA data sets). Both qualitative and quantitative validation with respect to ground truth (delineated by an MRA expert) are provided. The proposed approach achieved a high segmentation accuracy with 84.37% Dice similarity coefficient, sensitivity of 86.14%, and specificity of 99.00%

Overall PAPR Reduction for MIMO OFDM Systems

Abstract Multiple Input Multiple Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) systems have been receiving a great attention as one of the solutions for achieving high speed, efficient, and high quality of service wireless communications. However, the main drawback of MIMO OFDM systems is high Peak to Average Power Ratio (PAPR) because of its sensitivity to the nonlinear distortions introduced by nonlinear devices. In MIMO OFDM systems, a straightforward way for PAPR reduction is to apply existing techniques separately on each transmit antenna. Therefore, a higher overall PAPR is obtained with increasing the number of transmit antennas. In this paper, Partial Transmit Sequences (PTS) technique is modified with different circular shifting approaches. They exploit the extra degree of freedom provided by the transmit antenna array to reduce the overall PAPR even with increasing the number of transmit antennas

Analysis of the Importance of Systolic Blood Pressure Versus Diastolic Blood Pressure in Diagnosing Hypertension: MRA Study.

© 2020 IEEE. Hypertension is one of the severest and most common diseases nowadays. It is considered one of the leading contributors to death worldwide. Specialists tend to diagnose hypertension taking into consideration both systolic and diastolic blood pressure (BP) measurements. However, some clinical hypothesis states that under 50 years of age, diastolic may be slightly more predictive of adverse events, while above that age, systolic may be more predictive. The question is should we give more value to systolic BP or diastolic BP when diagnosing diseases such as hypertension? Three different experiments were conducted in this study using magnetic resonance angiography (MRA) data to investigate this question. In each of these experiments, the following methodology was followed: 1) preprocess MRA data to remove noise, bias, or inhomogeneities, 2) segment the cerebral vasculature for each subject using a CNN-based approach, 3) extract vascular features that represent cerebral alterations that precede and accompany the development of hypertension, and 4) finally build feature vectors and classify data into either normotensives or hypertensives based on the cerebral alterations and the blood pressure measurements. The first experiment was conducted on original data set of 342 subjects. While the second and third experiments enlarged the original data set by generating more synthetic samples to make original data set large enough and balanced. Experimental results showed that systolic blood pressure might be more predictive than diastolic blood pressure in diagnosing hypertension with a classification accuracy of 89.3%

The Degree of Practicing Leadership Entrepreneurial Skills of Public Secondary School Principals in Jordan and its Relationship to some Variables درجة ممارسة مهارات الريادة القيادية لدى مديري المدارس الثانوية الحكومية في الأردن

Abstract: This study aimed to find out the degree of leadership entrepreneurial skills practiced by the heads of government secondary school principals in Jordan. The descriptive survey methodology was used, and the study sample reached (115) male and female principals, who were chosen by the random cluster method. To collect study data, a questionnaire was developed, consisting of (58) items, distributed over five domains: strategic vision, initiative, creativity innovation, risk taking, and achievement. The results of the study showed that the degree of entrepreneurial leadership skills among public secondary school principals from their point of view was high, and all tool domains were high. The results indicated that there were no statistically significant differences attributed to the variables: gender, academic qualification, region and years of experience for all domains. ملخص: هدفت هذه الدراسة إلى تعرف درجة ممارسة مهارات الريادة القيادية لدى مديري المدارس الثانوية الحكومية في الأردن. تم استخدام المنهج المسحي الوصفي، وبلغت عينة الدراسة (115) مديرًا ومديرة، تم اختيارهم بالطريقة العنقودية العشوائية، ولجمع بيانات الدراسة تم تطوير استبانه، تكونت من (58) فقرة، موزعة على خمسة مجالات، وهي: الرؤية الإستراتيجية، المبادأة، الإبداع والابتكار، المخاطرة، الإنجاز. أظهرت نتائج الدراسة أن درجة ممارسة مهارات الريادة القيادية لدى مديري المدارس الثانوية الحكومية من وجهة نظرهم جاءت على نحو عام مرتفعة، وكانت جميع مجالات الأداة مرتفعة، كما أشارت النتائج إلى عدم وجود فروق ذات دلالة إحصائية تعزى لمتغيرات: الجنس والمؤهل العلمي والإقليم وسنوات الخبرة عند جميع المجالات

Mineralogical and geochemical study of rodingites and associated serpentinized peridotite, Eastern Desert of Egypt, Arabian-Nubian Shield

We studied rodingite and rodingite-like rocks within a serpentinized ultramafic sequence and ophiolitic mélange at Um Rashid, in the Eastern Desert of Egypt. The Um Rashid ophiolite is strongly deformed, metamorphosed, and altered by serpentinization, carbonatization, listvenitization, rodingitization and silicification. The textures, whole-rock chemistry, and composition of fresh primary mineral relics show that the serpentinite protoliths were strongly melt-depleted harzburgite and minor dunite, typical of a supra-subduction zone fore-arc setting. The light-colored rocks replacing gabbro are divided on the basis of field relations, mineral assemblages and geochemical characteristics into typical rodingite and rodingite-like rock. Typical rodingite, found as blocks with chloritite blackwall rims within ophiolitic mélange, contains garnet, vesuvianite, diopside and chlorite with minor prehnite and opaque minerals. Rodingite-like rock, found as dykes in serpentinite, consists of hercynite, preiswerkite, margarite, corundum, prehnite, ferropargasite, albite, andesine, clinozoisite and diaspore. Some rodingite-like rock samples preserve relict gabbroic minerals and texture, whereas typical rodingite is fully replaced. Rodingite is highly enriched in CaO, Fe₂O₃, MgO, and compatible trace elements, whereas rodingite-like rock is strongly enriched in Al₂O₃ and incompatible trace elements. Based on geochemistry and petrographic evidence, both types of rodingitic rocks likely developed from mafic protoliths in immediate proximity to serpentinite but were affected by interaction with different fluids, most likely at different times. Typical rodingite development likely accompanied serpentinization and shows mineral assemblages characteristic of low-Si, high-Ca fluid infiltration at about 300 °C. Rodingite-like rock, on the other hand, likely developed from seawater infiltration

Mineralogical and geochemical study of rodingites and associated serpentinized peridotite, Eastern Desert of Egypt, Arabian-Nubian Shield

We studied rodingite and rodingite-like rocks within a serpentinized ultramafic sequence and ophiolitic mélange at Um Rashid, in the Eastern Desert of Egypt. The Um Rashid ophiolite is strongly deformed, metamorphosed, and altered by serpentinization, carbonatization, listvenitization, rodingitization and silicification. The textures, whole-rock chemistry, and composition of fresh primary mineral relics show that the serpentinite protoliths were strongly melt-depleted harzburgite and minor dunite, typical of a supra-subduction zone fore-arc setting. The light-colored rocks replacing gabbro are divided on the basis of field relations, mineral assemblages and geochemical characteristics into typical rodingite and rodingite-like rock. Typical rodingite, found as blocks with chloritite blackwall rims within ophiolitic mélange, contains garnet, vesuvianite, diopside and chlorite with minor prehnite and opaque minerals. Rodingite-like rock, found as dykes in serpentinite, consists of hercynite, preiswerkite, margarite, corundum, prehnite, ferropargasite, albite, andesine, clinozoisite and diaspore. Some rodingite-like rock samples preserve relict gabbroic minerals and texture, whereas typical rodingite is fully replaced. Rodingite is highly enriched in CaO, Fe₂O₃, MgO, and compatible trace elements, whereas rodingite-like rock is strongly enriched in Al₂O₃ and incompatible trace elements. Based on geochemistry and petrographic evidence, both types of rodingitic rocks likely developed from mafic protoliths in immediate proximity to serpentinite but were affected by interaction with different fluids, most likely at different times. Typical rodingite development likely accompanied serpentinization and shows mineral assemblages characteristic of low-Si, high-Ca fluid infiltration at about 300 °C. Rodingite-like rock, on the other hand, likely developed from seawater infiltration

Novel Approaches For Segmenting Cerebral Vasculature

In this chapter, we propose two segmentation approaches that are able to segment cerebral vasculature automatically and accurately. This would potentially help experts in the early analysis and diagnosis of severe diseases, specifically, multiple sclerosis