Investigation of Wireless Channel Asymmetry in Indoor Environments

Asymmetry is unquestionably an important characteristic of the wireless propagation channel, which needs to be accurately modeled for wireless and mobile communications, 5G networks, and associated applications such as indoor/outdoor localization. This paper reports on the potential causes of propagation asymmetry. Practical channel measurements at Khalifa University premises proved that wireless channels are asymmetric in realistic scenarios. Some important conclusions and recommendation are also summarized.Comment: Accepted in IEEE International Symposium on Antennas and Propagation (APS17), San Diego, California, 9-14 Jul. 2017. arXiv admin note: substantial text overlap with arXiv:1704.0687

Investigating the capability of pulsed ultrasound technology in improving the performance of surface water treatment systems

Surface water is an important resource for drinking water production. Due to increasing contamination caused by floods and urbanisation, the quality of surface water continues to deteriorate. This problem is currently addressed by increasing the chemical additives used in water treatment processes. This practice introduces health-related problems such as the formation of disinfection by-products (DBPs) and the increase of Al residues. The application of physical rather than chemical treatments is a logical solution to the above problems. When evaluating various physical treatments, ultrasound appears a sensible choice for improving contaminants removal from surface water. While numerous studies have addressed the application of ultrasound technologies in water treatment, most of these studies used single contaminant synthetic water samples which does not present a realistic assessment. The key focus of this study is using natural water samples with a representative mixture of contaminants. The main challenge cited regarding ultrasound application is high energy consumption. To tackle this issue, the use of pulsed ultrasound has been proposed in this study. An improved calorimetric technique has been developed and tested to provide a fair evaluation of energy conversion in ultrasonic reactors. Sonochemical efficiency (SE) based on •OH and H2O2 measurements for the ultrasonic system along with the new calorimetric technique were employed. The optimal location of pulsed ultrasound technology within the surface water treatment process was identified using natural water samples with different carbon origins. The optimal location was found to be prior to the coagulation stage. The operation of pulsed ultrasound in this location was optimized with regards to power, treatment time and pulse format. Total coliform, DOC and UV-vis measurements were applied along with chemical fractionation techniques to establish the optimal operating conditions. Overall, ultrasound treatments resulted in 10-70% of microbial removal and 7-15% of DOC removal with a decrease in the aromatic hydrophobic DOC and a marginal increase in the hydrophilic DOC. The effectiveness of these conditions in promoting further removal of contaminants with alum coagulation was also examined. Turbidity, DOC removal and residual Al were measured for alum coagulation with and without pulsed ultrasound pre-treatment. Response optimization showed that pulsed ultrasound pre-treatment increased turbidity and DOC removal and reduced residual Al. Analysis of downstream effects revealed that pulsed ultrasound pre-treatment increased total coliform removal, decreased trihalomethane formation potential (THMFP) and improved the settling of coagulation sludge. A large-scale laboratory magnetostrictive ultrasonic reactor operated on square-pulse waveform was designed and tested. It was observed that scaling up to 15 L improved sonochemical efficiency of ultrasonic reactor. Using a reactor tank with 45 inclined sides further improved sonochemical efficiency. The larger design was more energy efficient in removing water contaminants compared to the small scale. This study confirmed that pulsed ultrasound is an effective tool for improving surface water treatment system, however further investigations required using other coagulants and monitoring of subsequent effects on other DBPs. It is also important to evaluate the performance and economic viability of the large scale reactor in continuous systems

Khannour Battle 1889, Causes, Results, and Reactions in the Arabian Gulf: Documentary Research

This study deals with the Battle named “Khanour Battle”, a Castle in the city of Abu Dhabi, which took place in January and February of 1889 between the Qatari and Abu Dhabi forces, which was not a regular battle between the tribes like other battles in the Gulf region at that period. The study examines the reasons that led to this battle and the reactions that resulted from it, both locally and regionally

Exploring Symmetry in Wireless Propagation Channels

Wireless communications literature is very rich with empirical studies and measurement campaigns that study the nature of the wireless propagation channel. However, despite their undoubted usefulness, many of these studies have omitted a fundamental yet key feature of the physical signal propagation, that is, wireless propagation asymmetry. This feature does not agree with the electromagnetic reciprocity theorem, and the many research papers that adopt wireless channel symmetry, and hence rendering their modeling, unexpectedly, inaccurate. Besides, asymmetry is unquestionably an important characteristic of wireless channels, which needs to be accurately characterized for vehicular/mobile communications, 5G networks, and associated applications such as indoor/outdoor localization. This paper presents a modest and a preliminary study that reports potential causes of propagation asymmetry. Measurements conducted on Khalifa University campus in UAE show that wireless channels are symmetric in the absence of symmetry impairments. Therefore, care should be taken when considering some practical wireless propagation scenarios. Key conclusions and recommendation are summarized. We believe that this study will be inspiring for the academic community and will trigger further investigations within wireless propagation assumptions.Comment: Accepted in IEEE European Conference on Networks and Communications (EuCNC17), Oulu, Finland,12-15 Jun. 201

The classification of the modern arabic poetry using machine learning

In recent years, working on text classification and analysis of Arabic texts using machine learning has seen some progress, but most of this research has not focused on Arabic poetry. Because of some difficulties in the analysis of Arabic poetry, it was required the use of standard Arabic language on which “Al Arud”, the science of studying poetry is based. This paper presents an approach that uses machine learning for the classification of modern Arabic poetry into four types: love poems, Islamic poems, social poems, and political poems. Each of these species usually has features that indicate the class of the poem. Despite the challenges generated by the difficulty of the rules of the Arabic language on which this classification depends, we proposed a new automatic way of modern Arabic poems classification to solve these issues. The recommended method is suitable for the above-mentioned classes of poems. This study used Naïve Bayes, Support Vector Machines, and Linear Support Vector for the classification processes. Data preprocessing was an important step of the approach in this paper, as it increased the accuracy of the classification

Perception, Practice, and Attitude Toward Prostate-specific Antigen Test Among Sudanese Urologists

Background: The introduction of prostate-specific antigen (PSA) has revolutionized the diagnosis of prostate cancer (PC). However, there is a wide variation in the daily practice of PSA testing with ongoing efforts to increase its sensitivity. This study aims to evaluate the attitude of Sudanese urologists toward the PSA test in their daily practice. Methods: An online questionnaire was formed and sent to the academic group of Sudanese urologists; it was left for two months with weekly reminders. The group contains 135 members. Data were then collected and analyzed. Results: Of the 135 members, 83 (61.5%) responded to the questionnaire, all were males, with 43% of them being consultants, and 37% having an experience between 5 and 10 years. Most participants (85%) use the test according to international guidelines, the majority (60%) counsel patients before the test, with 72% finding the test more than 50% reliable. In addition, >33% face problems when requesting PSA with >29% of them finding it unreliable. Moreover, in >13%, the test is unavailable. Nearly all participants (95%) think that there is a need for national guidelines to regulate the use of PSA tests. Conclusion: For the diversity of practice toward the PSA test and the unavailability of adjunct methods that increase its sensitivity, there is a need for national guidelines to regulate the use of the test in the context of other clinical factors

Radiation Patterns Account of a Circular Microstrip Antenna Loaded Two Annular

In this paper, theoretical study of circular microstrip antenna loaded two annular (CMSAL2AR) and calculation of the radiation pattern using principle equivalence with moment of method formulation of electromagnetic radiation in this these based on the bodies of revolution (BoR), which are generated by revolution a planar curve about an axis called axis of symmetry to solving the electric fields integral equation (EFIE) and magnetic field integral equation (MFIE). To find an unknown electric current density  on the conductor surface ,and both unknowns electric and magnetic density  current on the dielectric surface which are  responsible for the generation of far fields radiation in the space for the components (Eθ ,Eφ) ,the surface currents was represented by a set of basis functions that give the Fourier series because the body has a circular symmetry property and then select a set of weighted  functions to find a linear system by using.......

Designing a Microstrip Patch Antenna in Part of Ultra-Wideband Applications

في هذه الدراسة، أجريت دراسة محاكاة لتصميم هوائي شريطي مع رقعة مستطيلة لولبية جديدة والذي يُستخدم في تطبيقات النطاق الترددي العريض الفائق وباستخدام برنامج محاكاة التراكيب عالية التردد (high frequency structure simulator software (HFSS)) . تم استخدام شريحة عازلة بقيمة ثابت عزل يساوي 4.4 وارتفاع 2.10 ملم لتصميم الهوائي المقترح. أن أساس التصميم يستند على زيادة عرض النطاق الترددي ضمن الحزمة الترددية 6.63 - 10.93 كيكاهرتز من خلال زيادة مناطق الحافة للمشع والتي تؤثر إيجابًا على كفاءة الهوائي. أن هذا التصميم يجعل تكلفة تصميم الهوائي اقل من خلال تقليل مساحة المشع. لاحظنا أن عرض النطاق الترددي للهوائي في هذه الدراسة يزداد إلى 4.30 كيكاهرتز أو ما يعادل 61٪ مقارنةً بالنسبة 3.6٪ الناتجة عن الهوائي الشريطي المستطيل القياسي مع نفس أبعاد الهوائي المقترح. أن الهوائي المقترح حافظ على نسبة موجة الفولتية القياسية الواقفة (voltage standing wave ratio) وهي 1.09 عند التردد الرنيني  7.7  كيكاهيرتز، وعامل الفقد 27.07  ديسبل، وان قيمة الجزء الحقيقي والخيالي للممانعة هي 51.5  أوم و 3.3  أوم ، على الترتيب.In this work, a simulated study was carried out for designing a novel spiral rectangular patch of microstrip antenna that is used in ultra-wideband applications by using a high frequency structure simulator software (HFSS). A substrate with dielectric constant of 4.4 and height 2.10 mm (commercial substrate height available is about 0.8-1.575 mm) has been used for the design of the proposed antenna. The design basis for enhancing bandwidth in the frequency range 6.63 - 10.93 GHz is based on increasing the edge areas that positively affect the antenna's efficiency. This design makes the designed antenna cost less by reducing the area of the patch. It has been noticed that the bandwidth of the antenna under this study is increasing to 4.30 GHz or 61% compared with 3.6% for the standard rectangular microstrip antenna with the same dimensions of the proposed antenna. The antenna also maintains the voltage standing wave ratio of 1.09 at resonant frequency 7.07 GHz, return loss -27.07 dB, and the amount of impedance in real and imaginary parts 51.5Ω and 3.3Ω, respectively

Defense in Depth: Multilayer of security

Many types and methodologies of attacks have been developed in order to target the victims in different ways affecting its resources and assets. This paper reviews the defense in depth concept that has been developed in which multilayer of security controls are implemented to protect resources and assets from such attackers through consuming all the resources and capabilities of the attacker before malicious activities affect such targeted resources and assets

Knowledge and Attitude of Oral Health Professionals in the Management of Avulsed Teeth

Objectives: The purpose of this study is to assess the knowledge and to compare the attitude and management of tooth avulsion between the general dentist and the specialist all with dental interns.  Materials and Methods:16-point questionnaires have been developed to a similar study and have been validated by a group of specialist.  The first part of the survey contained demographic data. The second part consisted of eight questions checking dentists’ knowledge on the treatment of avulsed teeth. All in which took part in Saudi Arabia, Riyadh and covered 311 dentists. Data were analyzed with SPSS program version 21Results: 583 questionnaires have been distributed and a total of 311 were collected. Which consisted 53.34% of distributed surveys. Almost two-third (219) of the surveyed populations have never treated any patient with dental avulsion. Amongst those who had such experience, the majority treated at least one case (35.9%), there were also 22 (23.9%) dentist who treated more than 5 avulsed teeth. 25 of 311 dentist have never received education or training in the management of tooth avulsion. Conclusion: there is a need to familiarize oral health professions with the needed knowledge and management of avulsion through lectures and proper training. Keywords: Avulsion; knowledge; management; oral professional; denta