Resource allocation for transmit hybrid beamforming in decoupled millimeter wave multiuser-MIMO downlink

This paper presents a study on joint radio resource allocation and hybrid precoding in multicarrier massive multiple-input multiple-output communications for 5G cellular networks. In this paper, we present the resource allocation algorithm to maximize the proportional fairness (PF) spectral efficiency under the per subchannel power and the beamforming rank constraints. Two heuristic algorithms are designed. The proportional fairness hybrid beamforming algorithm provides the transmit precoder with a proportional fair spectral efficiency among users for the desired number of radio-frequency (RF) chains. Then, we transform the number of RF chains or rank constrained optimization problem into convex semidefinite programming (SDP) problem, which can be solved by standard techniques. Inspired by the formulated convex SDP problem, a low-complexity, two-step, PF-relaxed optimization algorithm has been provided for the formulated convex optimization problem. Simulation results show that the proposed suboptimal solution to the relaxed optimization problem is near-optimal for the signal-to-noise ratio SNR <= 10 dB and has a performance gap not greater than 2.33 b/s/Hz within the SNR range 0-25 dB. It also outperforms the maximum throughput and PF-based hybrid beamforming schemes for sum spectral efficiency, individual spectral efficiency, and fairness index

The Theory of Critical Distance to design 3D printed notched components

The three-dimensional (3D) printing technology is a manufacturing technique for fabricating a wide range of structures and complex geometries from 3D model data. The fused deposition modelling is a common additive manufacturing (AM) technique in this industry, using filaments of raw material to produce the final product, while Polylactic acid (PLA) is considered to be one of the most convenient polymers for use in this kind of fabrication. The PLA components produced by this technique are usually required to maintain good mechanical properties in several applications, especially when they are manufactured with complex geometries resulting in high stress concentration. Therefore, it is recommended to investigate the strength of AM PLA components under different kinds of loading. The Theory of Critical Distances (TCD) is the name that has been given to a group of design methodologies that are considered highly precise and reliable tools for predicting the static strength of brittle notched materials. The TCD represents an ideal method for optimising the mechanical properties of 3D printed PLA parts used in sensitive applications like tissue engineering. In this respect, this study used the TCD to predict the strength of a large number of AM PLA components, tested under both tensile and bending loading and containing different geometrical features. Two groups of specimens were tested in this experimentally based study. The first group was solid AM PLA with an infill ratio of 100%. The influence of several printing parameters on the strength of plain specimens was investigated. The TCD’s validity as a method for determining static strength of notched PLA specimens was checked with different notch shapes and root radii, under tension and bending loading. The TCD was found to be highly accurate in estimating the static strength of notched AM PLA solid specimens, with its use returning estimates falling mainly within an error interval of ±20%. The second group of specimens was for AM PLA plain and notched porous specimens manufactured with variable infill levels. A novel approach combining conventional TCD with the equivalent homogenised material concept was formulated to perform a static assessment of plain/notched objects of PLA when this polymer is additively manufactured with different infill levels. The key idea was that the internal net structure resulting from the 3D-printing process could be modelled by treating the material as a continuum, homogenous and isotropic, thus allowing the internal voids to be considered in terms of the change in their mechanical/strength properties. This idea was initially applied by addressing this problem in a Kitagawa-Takahashi setting via the Theory of Critical Distances, for plain porous specimens. Subsequently, the approach was extended to the static strength assessment of notched porous components of 3D-printed PLA. The results showed that the TCD applied alongside the equivalent homogenised material concept was able to model successfully the static strength of plain AM PLA materials, as well as notched materials, fabricated with variable infill levels. Again, predictions fell mainly within an error interval of ±20%

What is Hidden, in the Hidden Economy of Pakistan? Size, Causes, Issues and Implications

There is a worldwide contemporary debate about the role of the hidden economy in achieving the goal of sustained and inclusive economic growth and development, especially in the context of its spillover effects on the formal economy. For this purpose, policy makers and academicians have made concerted efforts to estimate the size of the hidden economy and to analyze its causes, issues and implications on key macroeconomic variables. However, there is a consensus among the policy makers that a better macroeconomic policy formulation and its true implementation are subject to the proper management of the associated issues of the hidden economy with suitable policy measures. In Pakistan, it is generally assumed that the hidden economy contributes about 30% to 50% to the overall GDP. The purpose of this paper is to estimate more precisely the size of the hidden economy with the determination of its potential causes and implications. Five statistical and structural modeling approaches namely; simple monetary approach, modified monetary approach using dynamic ordinary least square (DOLS), multiple-indicators multiple-causes (MIMIC) approach, electricity consumption approach and labor market survey based approach are used to estimate the size of the hidden economy and to analyze the characteristic nature of its growth over the period. The study also investigates the potential determinants of the hidden economy and various interrelated socio-economic issues in perspective of achieving national goal of inclusive growth and development. Finally, policy implications are provided consistent with pervading facts of the hidden economy in Pakistan especially in the context of the 18th Amendment and the 7th NFC Award.Hidden Economy, Size, Causes, Socio-Economic Implications, Inclusive Growth and Development, 18th Amendment and 7th NFC Award of Pakistan

Simulating and comparing Tangle 2.0 and PoW

Tangle 2.0 is a leaderless probabilistic consensus protocol that is based on a DAG called Tangle. The way consensus is found is in the heaviest DAG and not in the longest chain which is popular in Blockchain. POW is a consensus protocol most known for being used in Bitcoin. The nodes in a POW system have to solve a complex mathematical puzzle that satisfies a difficulty threshold before a new block can be published to the network. Because Tangle 2.0 is such a complex protocol we wish to find out if it has an edge over a traditional consensus protocol such as PoW. We modify the Tangle 2.0 simulating tool by adding POW as the consensus protocol. We compare the original Tangle 2.0 with POW by metrics such as the confirmation time of network messages. Adding POW as the consensus protocol in Tangle 2.0 creates a greedy-heaviest sub-tree structure which has led to forks. We have found that because of forks in the POW network, slowing down the network throughput will eventually rid the network of forks. But leads to a higher confirmation time. So the comparison shows a significant benefit for Tangle 2.0

Jordanian Legislation, Civil Liability and Compensation for Damages to the Environment

The Industrial Revolution was mainly caused by industrial and technological developments. However, this revolution has influenced environmental pollution to a large extent. Natural resources and ecosystem balance have been put under pressure, with food, water and air being polluted. Hence, it is essential to realize the damage being done to the environment on a global basis and to establish strategies to protect human health and the environment at large. In the present research, Jordanian legislation is assessed within the context of the environment, where pollution risks are present. The concept of responsibility has not been analyzed appropriately, which is why the environmental protection regulations and laws are also analyzed. There exists a legislative gap, which could be filled by stating the general norms of adequacy. Keywords: Jordanian Legislation, Civil liability, Compensation, Environment

Investigating the Effects of Microwave Furnaces Heat on the Mechanical Properties and Fatigue Life of AA6061-T6 Alloy

ان الغرض الاساسي من هذة الدراسة هي لمعرفة مدى تأثير حرارة طاقة افران المايكروويف على سطح سبيكة الألمنيوم من نوع&nbsp; AA6061-T6 , وكذلك لبحث مدى التغير الحاصل في الخواص الميكانيكية وعمر الكلال المحسوب من خلال أوساط أختبار (وسط جاف ووسط ملحي) ولفترتين زمنيتين (نصف ساعة وساعة كاملة داخل الفرن). وجد ان الحرارة الناجمة من الطاقة موجات أفران المايكروويف اثرت في الاجهاد الاقصى وكذلك أجهاد الخضوع كما كان لها تأثير كذلك على خشونة السطح, الصلادة وكذلك معامل المرونة حيث كانت معدلات تلك التغيرات تختلف تبعاً للوقت الذي تعرضت له لموجات المايكروويف. تأثر عمر الكلال المحسوب كذلك بتلك العملية وكانت اعلى معدلات تلك التأثير هي عند التعرض لحرارة طاقة موجات المايكروويف لمدة ساعة كاملة. تمت مقارنة كافة تلك التغييرات مع النتائج الاولية المستحصلة لنفس السبيكة من دون معاملة ووفق معايير قياسية بجداول مثبتة داخل متن الدراسة. تهدف الدراسة ايضاً لدحظ المفهوم الخاطئ حول محاذيير استخدام المعادن داخل تلك الافران والاثبات انه&nbsp; بالامكان استعمالها وفق ضوابط متحكم بها مسبقاً.The objective of this research is to determine the effect of microwave furnaces heat energy on the surface of an aluminum alloy AA 6061-T6, also, to investigate the range of change in mechanical properties and the estimated fatigue life have through different medium (dry and salt solution) and duration times (0.5-1 hour). It was found that the heat generated by the energy of the microwave furnace affected the ultimate stress and the yield stress as well as surface roughness, hardness and modulus of elasticity, where degrees varied according to the time of exposure to those waves. The estimate fatigue life was also affected by heat generated through the energy of the microwave furnace. The highest range of change was when the alloy specimen was subjected to microwave heat energy for one hour. All the variation was compared with the properties of the alloy without treatments as received (ASTM Standards) in tables within the research. Also, the research aims to change the wrong idea about not using metals with the microwaves furnace and to prove it's safe to do that through controlled steps.&nbsp

Study of the Electrical and Structural/Micro structural Properties of Bi2-xAgxBa2-ySryCa2Cu3O10+? System

This study included preparing samples of the compound  (Bi2Ba2Ca2Cu3O10+?) by the reaction of the solid state under a hydrostatic pressure 8 ton/cm2 and annealing temperature 840oC . X-ray diffraction (XRD), scanning electron microscopy (SEM), dc electrical resistivity measurements by four point probe method were used to investigate the microstructural and superconducting properties of Bi¬2223 samples.  The X-rays diffraction study for the compound   (Bi2Ba2Ca2Cu3O10+? ) showed that it has Tetragonal type of crystal structure .The partial replacement of the component Ag in Bi, and Sr component  in Ba simultaneously, the compound becomes (Bi2-xAgxBa2-ySryCa2Cu3O10+?) with (x ,y) values equal to (x= 0.2, y= 0.1, 0.2, 0.3,0.4). The study of the crystal structure test showed that the structure retains on the tetragonal type with a high Tc phases (2223), low Tc phase(2212) and impurity phases, and the critical temperature Tc steps-up from (125 K) to (137 K) at substitution rate (x= 0.2, y= 0.1). But at increasing the substitution rate for (y) and the stability of (x) rate more than (x= 0.2, y= 0.1), the temperature declines to (108 K). Finally, the microstructural of the samples has been studies and tested by Scanning Electron Microscope for knowing the components' rates in the compound; how the compound partial substitution affect in the components; and specifying the quantitative and qualitative rates of the components in the compound. Keywords: Bi-based, Bi-2223, Partial Substitution, Crystal Structure, Bi-Ba-Ca-Cu-O, LT phase , HT phase

Communication based loss-of-mains protection method by frequency correlation

Due to the increasing penetration of distributed generation (DGs) in the distribution network in high numbers and proportions, and its conspicuous impact on power system stability. This occurs during a wide system disturbance in the power system, the DGs will start to disconnect from the main source in large proportions. This will further affect the power system stability and causes damages to its components and DGs. This thesis investigates in the reliability, security, and efficiency of satellite and internet communications, specifically for loss of mains (LOM) protection and exploring the strengths, the weaknesses, the feasibility of each type of communications, and the requirements of communication system components. By using communications network to send Phasor Measurement Unit (PMU) data to DGs protection equipment that are connected at remote areas all over UK, the LOM protection can be improved, obtain synchronization, precision, and coordination among power protection components. Satellite communication is chosen as it makes a better communication method when it comes to the installation, construction, urban disruption, time saving, and the installation and annual cost on every participant. However, the high latency issue is approached and solved by making a few changes in the communication protocol format and the data requirements to reduce the effect of latency to a level that can be tolerated. This thesis presents the development of a novel LOM protection method based on communication and frequency correlation. The stability and sensitivity assessment will show that this method is highly secure and reliable. It can also withstand a communication delay of 120ms without causing any nuisance tripping, and have a relay response to LOM operation of a maximum of 1s. The thesis also presents a novel method in time delay estimation that has been developed for power system applications. This method is called the Linear Trajectory Path (LTP) and its performance fulfils the LOM synchronisation requirements by succeeding in determining the time delay between the two data streams within the tolerated estimation error of ±100ms.Due to the increasing penetration of distributed generation (DGs) in the distribution network in high numbers and proportions, and its conspicuous impact on power system stability. This occurs during a wide system disturbance in the power system, the DGs will start to disconnect from the main source in large proportions. This will further affect the power system stability and causes damages to its components and DGs. This thesis investigates in the reliability, security, and efficiency of satellite and internet communications, specifically for loss of mains (LOM) protection and exploring the strengths, the weaknesses, the feasibility of each type of communications, and the requirements of communication system components. By using communications network to send Phasor Measurement Unit (PMU) data to DGs protection equipment that are connected at remote areas all over UK, the LOM protection can be improved, obtain synchronization, precision, and coordination among power protection components. Satellite communication is chosen as it makes a better communication method when it comes to the installation, construction, urban disruption, time saving, and the installation and annual cost on every participant. However, the high latency issue is approached and solved by making a few changes in the communication protocol format and the data requirements to reduce the effect of latency to a level that can be tolerated. This thesis presents the development of a novel LOM protection method based on communication and frequency correlation. The stability and sensitivity assessment will show that this method is highly secure and reliable. It can also withstand a communication delay of 120ms without causing any nuisance tripping, and have a relay response to LOM operation of a maximum of 1s. The thesis also presents a novel method in time delay estimation that has been developed for power system applications. This method is called the Linear Trajectory Path (LTP) and its performance fulfils the LOM synchronisation requirements by succeeding in determining the time delay between the two data streams within the tolerated estimation error of ±100ms

MATERNAL EFFECTS ON GROWTH PARAMETERS OF CHLORIS GAYANA UNDER CO2 ENRICHMENT

Rhodes grass, Chloris gayana, is commonly used forage plant for grazers, livestock, and cattle. It significantly improves soil fertility and its overall structure by preventing nematode flourishment in soil. It is also used as a cover crop to upgrade soil health by reducing soil erosion and increasing water availability. The present study assessed the effects of CO2 on the growth, development and maternal effects of C. gayana. The experimental setup was made in such a way that the potential impacts of CO2 can be measured on the eco-physiological growth of C. gayana by studying successive generations. Generation 1 was grown by sowing the seeds of C. gayana in soil pots and generation 2 was propagated by cutting and regenerating the branches with their roots from generation 1 plants. Growth parameters including plant height, number of leaves, shoot/root ratio, chlorophyll content, stomatal conductance, and photosynthetic rate were measured at regular intervals in both generations. Significant differences in the growth parameters were observed in both generation 1 and 2 plants when plants were grown under enriched and ambient CO2 conditions. The varying pattern of phenotypes in the generation 2 plants can be justified based on the Bet-hedging maternal effects. We hypothesize that the Rhodes grass parent plants when allowed to grow under ambient and enriched CO2 conditions influenced the offspring plants by producing a variety of phenotypes to sustain maternal fitness. The present study can be helpful in understanding the C. gayana growth conditions and the vertical transfer of maternal effects from one generation to the other

The Impact of GDP, FDI, and Import on Carbon Dioxide Emissions in of GCC Countries: A Panel Data Approach

The GCC countries’ unified economic agreement which has been signed on 1981 and activated in 2002 aimed for easing free trade and attract more FDI to enhance the level of economic growth. This agreement has also emphasized on reducing levels of pollution and achieving a sustainable economic growth. In reality, there is an increase in the level of emissions along with the level of rising of economic growth in GCC countries. Accordingly, in this study we will test the most significant variables pertaining to the increasing carbon dioxide emissions in GCC countries. The research objective is to determine how much the FDI inflows, economic growth, and commodity imports influenced the increasing level of emissions, and which variable has most effect? For this purpose, an empirical model is specified as a function of FDI inflows, per capita GDP growth rate, and commodity imports. However, we have built this model based on Environmental Kuznets Curve assumption (EKC), as well as Pollution Haven Hypothesis (PHH). It will be examined simultaneously a 66 balanced observation of the six GCC countries within the panel data technique using cross-section random effects