198 research outputs found

    Digital tanlock loop architecture with no delay

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    This article proposes a new architecture for a digital tanlock loop which eliminates the time-delay block. The �=2 (rad) phase shift relationship between the two channels, which is generated by the delay block in the conventional timedelay digital tanlock loop (TDTL), is preserved using two quadrature sampling signals for the loop channels. The proposed system outperformed the original TDTL architecture, when both systems were tested with frequency shift keying input signal. The new system demonstrated better linearity and acquisition speed as well as improved noise performance compared with the original TDTL architecture. Furthermore, the removal of the time-delay block enables all processing to be digitally performed, which reduces the implementation complexity. Both the original TDTL and the new architecture without the delay block were modelled and simulated using ATLAB/Simulink. Implementation issues, including complexity and relation to simulation of both architectures, are also addressed

    Performance evaluation of the time delay digital tanlock loop architectures

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    This article presents the architectures, theoretical analyses and testing results of modified time delay digital tanlock loop (TDTLs) system. The modifications to the original TDTL architecture were introduced to overcome some of the limitations of the original TDTL and to enhance the overall performance of the particular systems. The limitations addressed in this article include the non-linearity of the phase detector, the restricted width of the locking range and the overall system acquisition speed. Each of the modified architectures was tested by subjecting the system to sudden positive and negative frequency steps and comparing its response with that of the original TDTL. In addition, the performance of all the architectures was evaluated under noise-free as well as noisy environments. The extensive simulation results using MATLAB/SIMULINK demonstrate that the new architectures overcome the limitations they addressed and the overall results confirmed significant improvements in performance compared to the conventional TDTL system

    Synchronization of a renewable energy inverter with the grid

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    The design, mathematical analysis, and testing results of the architecture of a new all-digital phase-locked loop system for synchronizing a voltage source DC-AC single-phase inverter with the low voltage utility grid are presented. The system which is based on the time-delay digital tanlock loop was simulated using MATLAB/ SIMULINK and was tested by subjecting the grid voltage to various perturbations similar to those which can occur in a real power system, such as voltage sags and nonlinear distortion of the grid voltage waveform. Results indicate that even in the presence of such perturbations the system achieved and/or re-gained synchronization within 100 ms. The proposed system is all-digital and can be readily implemented using a field programmable gate array and easily embedded into a power inverter

    ARP Spoofing

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    This paper attempts to provide the methods black hat hackers utilize ARP Spoofing to gain access to unauthorized machines, steal data and attack systems. This research includes theory and practical examples to carry out each of the attacks. In the attempt of figuring out how black hat hackers exploit system vulnerabilities and gain unauthorized access; the virtual machine Kali/Linux and some Python programming language will be used. The research delves into the following subjects; Mac Address, Network Scanner and ARP Spoofin

    Evaluation of the impact of international standards set by “the basle committee on banking supervision” on Jordanian law

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    Formulating international standards on banking supervision is one of the most important topics of international financial law. The recent international financial crisis is another striking example on the significance and relevance of this subject. This thesis attempts to evaluate the impact of international standards of banking supervision aimed at the creation of a "safe and sound" banking system on Jordanian legislation at two levels: to what extent international standards set out by the Basel Committee on Banking Supervision ("BCBS") have influenced Jordanian law; and how these standards can assist in improving the Jordanian law as well as direct new policy reforms. The first finding of the thesis is that Jordanian law is significantly compliant with international standards. The second main finding is that soft law, as opposed to hard law, is the optimal form of setting international banking supervisory standards. The thesis also finds that the BCBS standards do not provide adequate guidance on the structure of the banking supervisory authority. The thesis concludes with recommendations on how to enhance international banking supervisory standards as well as the structure and substantive law of banking supervision in Jordan in light of international standards and with occasional reference to the UK Law

    Red cell genotyping precision medicine: a conference summary

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    This review summarizes the salient points of the symposium ‘Red Cell Genotyping 2015: Precision Medicine’ held on 10 September 2015 in the Masur Auditorium of the National Institutes of Health. The specific aims of this 6th annual symposium were to: (1) discuss how advances in molecular immunohematology are changing patient care; (2) exemplify patient care strategies by case reports (clinical vignettes); (3) review the basic molecular studies and their current implications in clinical practice; (4) identify red cell genotyping strategies to prevent alloimmunization; and (5) compare and contrast future options of red cell genotyping in precision transfusion medicine. This symposium summary captured the state of the art of red cell genotyping and its contribution to the practice of precision medicine

    A nonuniform DPLL architecture for optimized performance

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    This paper presents the design, analysis, simulation, and implementation of the architecture of a new nonuniform-type digital phase-locked loop (DPLL). The proposed loop uses a composite phase detector (CPD), which consists of a sample-and-hold unit and an arctan block. The CPD improves the system linearity and results in a wider lock range. In addition, the loop has an adaptive controller block, which can be used to minimize the overall system sensitivity to variations in the power of the input signal. Furthermore, the controller has a tuning mechanism that gives the designer the flexibility to customize the loop parameters to suit a particular application. These performance parameters include lock range, acquisition time, phase noise or jitter, and signal-to-noise ratio enhancement. The simulation results show that the proposed loop provides flexibility to optimize the major conflicting system parameters. A prototype of the proposed system was implemented using a field-programmable gate array (FPGA), and the practical results concur with those obtained by simulation using MATLAB/Simulink. © 2013 Institute of Electrical Engineers of Japan.Published versio

    Design and optimization of electrochemical cell potential for hydrogen gas production

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    © 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences This study deals with the optimization of best working conditions in molten melt for the production of hydrogen (H2) gas. Limited research has been carried out on how electrochemical process occurs through steam splitting via molten hydroxide. 54 combinations of cathode, anode, temperature and voltage have been investigated for the optimization of best working conditions with molten hydroxide for hydrogen gas production. All these electrochemical investigations were carried out at 225 to 300°C temperature and 1.5 to 2.5 V applied voltage values. The current efficiency of 90.5, 80.0 and 68.6% has been achieved using stainless steel anodic cell with nickel, stainless steel and platinum working cathode respectively. For nickel cathode, an increase in the current directly affected the hydrogen gas flow rate at cathode. It can be hypothesized from the noted results that increase in current is directly proportional to operating temperature and applied voltage. Higher values were noted when the applied voltages increased from 1.5 to 2.5 V at 300°C, the flow rate of hydrogen gas increased from 1.5 to 11.3 cm3 min−1, 1.0 to 13 cm3 min−1 in case of electrolysis @ stainless steel and @ graphite anode respectively. It is observed that the current efficiency of stainless steel anodic cell was higher than the graphite anodic cell. Therefore, steam splitting with the help of molten salts has shown an encouraging alternate to current methodology for H2 fuel production

    Islamism and the state after the Arab uprisings: Between people power and state power

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    The authors would like to thank the Arts and Humanities Research Council for facilitating the research for this article through their support of the research network People Power versus State Power of the Centre for the Advanced Study of the Arab World.This paper examines the trajectories of different Islamist trends in the light of the Arab uprisings. It proposes a distinction between statist and non-statist Islamism to help understand the multiplicity of interactions between Islamists and the state, particularly after 2011. It is outlined how statist Islamists (Islamist parties principally) can contribute to the stabilization and democratization of the state when their interactions with other social and political actors facilitate consensus building in national politics. By contrast when these interactions are conflictual, it has a detrimental impact on both the statist Islamists, and the possibility of democratic politics at the national level. Non statist-Islamists (from quietist salafi to armed jihadi) who prioritize the religious community over national politics are directly impacted by the interactions between statist Islamists and the state, and generally tend to benefit from the failure to build a consensus over democratic national politics. Far more than nationally-grounded statist Islamists, non-statist Islamists shape and are shaped by the regional dynamics on the Arab uprisings and the international and transnational relations between the different countries and conflict areas of the Middle East. The Arab uprisings and their aftermath reshaped pre-existing national and international dynamics of confrontation and collaboration between Islamists and the state, and between statist and non-statists Islamists, for better (Tunisia) and for worse (Egypt).PostprintPeer reviewe
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