Low-complexity LSMR equalisation of FrFT-based multicarrier systems in doubly dispersive channels

The discrete fractional Fourier transform (FrFT) has been suggested to enhance performance over DFT-based multicarrier systems when transmitting over doubly-dispersive channels. In this paper, we propose a novel low-complexity equaliser for inter-symbol and inter-carrier interference arising in such multicarrier transmission system. Due to a lower spreading in the FrFT-domain compared to the DFTchannel matrix as compared to the DFT domain, the equaliser cam approximate the fractional-domain channel matrix by a band matrix. Further, we utilise the least squares minres (LSMR) algorithm in the calculation of the equalisation, which exhibits attractive numerical properties and low complexity. Simulation results demonstrate the superior performance of the proposed LSMR equaliser over benchmark schemes

Chirp-based multicarrier modulation

In this paper we demonstrate that in doubly-dispersive environments, a multicarrier (MC) system based on a fractional Fourier transform (FrFT) can achieve a better concentration of power near the main diagonal of the equivalent channel matrix compared to standard orthogonal frequency division multiplexing (OFDM). The resulting inter-symbol and inter-carrier interference in such a chirp- based MC system can therefore be suppressed with a reduced complexity equaliser. Simulations show that compared to an equalised OFDM system, the equalised FrFT-MC approach can either significantly reduce complexity or enhance performance in a time-varying environment

The estimate of amplitude and phase of harmonics in power system using the extended kalman filter

Nowadays, the amplitude of the harmonics in the power grid has increased unwittingly due to the increasing use of the nonlinear elements and power electronics. It has led to a significant reduction in power quality indicators. As a first step, the estimate of the amplitude, and the phase of the harmonics in the power grid are essential to resolve this problem. We use the Kalman filter to estimate the phase, and we use the minimal squared linear estimator to assess the amplitude. To test the aforementioned method, we use terminal test signals of the industrial charge consisting of the power converters and ignition coils. The results show that this algorithm has a high accuracy and estimation speed, and they confirm the proper performance in instantaneous tracking of the parameters

DESIGN, OPTIMIZATION AND IN VITRO EVALUATION OF ANTIFUNGAL ACTIVITY OF NANOSTRUCTURED LIPID CARRIERS OF TOLNAFTATE

Objective: The main purpose of this work was to prepare tolnaftate (TOL) loaded nanostructured lipid carriers (NLCs), Evaluate its characteristics and in vitro release study. Methods: Tolnaftate loaded Nanostructured lipid carriers were prepared by the high shear homogenization method using different liquid lipids types (DERMAROL DCO® and DERMAROL CCT®) and concentrations, different concentration ratios of tween80® to span20® and different homogenization speeds. All the formulated nanoparticles were subjected to particle size (PS), zeta potential (ZP), polydispersity index (PI), drug entrapment efficiency (EE), Differential Scanning Calorimetry (DSC), Transmission Electron microscopy (TEM), release kinetics and in vitro release study was determined. Results: The results revealed that NLC dispersions had spherical shapes with an average size between 154.966±1.85 nm and 1078.4±103.02 nm. High entrapment efficiency was obtained with negatively charged zeta potential with PDI value ranging from 0.291±0.02 to 0.985±0.02. The release profiles of all formulations were characterized by a sustained release behavior over 24 h and the release rates increased as the amount of surfactant decreased. The release rate of TOL is expressed following the theoretical model by Higuchi. Conclusion: From this study, It can be concluded that NLCs are a good carrier for tolnaftate deliver

Network coding cooperation performance analysis in wireless network over a lossy channel, M users and a destination scenario

Network coding (NC), introduced at the turn of the century, enables nodes in a network to combine data algebraically before either sending or forwarding them. Random network coding has gained popularity over the years by combining the received packet randomly before forwarding them, resulting in a complex Jordan Gaussian Elimination (JGE) decoding process. The effectiveness of random NC is through cooperation among nodes. In this paper, we propose a simple, low-complexity cooperative protocol that exploits NC in a deterministic manner resulting in improved diversity, data rate, and less complex JGE decoding process. The proposed system is applied over a lossy wireless network. The scenario under investigation is as follows: M users must send their information to a common destination D and to exchange the information between each others, over erasure channels; typically the channels between the users and the destination are worse than the channels between users. It is possible to significantly reduce the traffic amon g users and destination, achieving significant bandwidth savings, by combining packets from different users in simple, deterministic ways without resorting to extensive header information before being forwarded to the destination and the M users. The key problem we try to address is how to efficiently combine the packets at each user while exploiting user cooperation and the probability of successfully recovering information from all users at D with k < 2M unique linear equations, accounting for the fact that the remaining packets will be lost in the network and there are two transmission stages. Simulation results show the behaviour for two and three transmission stages. Our results show that applying NC protocols in two or three stages decreases the traffic significantly, beside the fact that the proposed protocols enable the system to retrieve the lost packets rather than asking for ARQ, resulting in improved data flow, and less power consumption. In fact, in some protocols the ARQ dropped from the rate 10-1 to 10-4, because of the proposed combining algorithm that enables the nodes to generate additional unique linear equations to broadcast rather than repeating the same ones via ARQ. Moreover, the number of the transmitted packets in each cooperative stage dropped from M (M − 1) to just M packets, resulting to 2 M packets instead 2 (M2 −  1) when three stages of transmission system are used instead of one stage (two cooperative stages)

التقنيات الرقمية لإحكام الجداول الزمنية لمشاريع التشييد تحليل مبنى على المراجعات الأدبية للإتجاهات والتحديات Digital Technologies to Enhance Construction Schedules Literature-based Analysis for Trends and Challenges

على الرغم من الجهود الكبيرة التي تبذلها الجهات الحكومية السعودية لتجنب تأخير وتعثر مشاريع التشييد، الا ان أغلب الدراسات المعاصرة أظهرت أنه مازال هناك نسبة كبيرة من المشاريع متأخرة ومتعثرة نتيجة لعوامل متعددة منها ضعف إعداد الجدول الزمني للمشروع، وذلك على الرغم من توافر العديد من التقنيات الرقمية التي يمكنها دعم تطوير وإحكام هذه الجداول لتحقيق أهداف المشاريع، وهو ما يمثل الإشكالية الرئيسية لهذه الدراسة التي تستهدف دراسة الإتجاهات المعاصرة للتقنيات الرقمية ذات العلاقة بالجداول الزمنية لمشاريع التشييد، والتحديات التي تواجه تطبيقها، والوصول إلى إطار لتوظيفها في إحكام الجداول الزمنية لمشاريع التشييد. ولتحقيق هذه الأهداف تبنت الدراسة المنهج البحثي الوصفي التحليلي اعتماداً على المراجعات الأدبية للإتجاهات والتحديات التي تواجه تطبيق هذه التقنيات. وناقشت الدراسة أربعة من الإتجاهات المعاصرة لإحكام الجداول الزمنية وثلاثة من أهم التحديات التي تواجهها وخلصت إلى إطار العمل المستهدف وعدد من النتائج والتوصيات المهمة لمعالجة إشكالية الدراسة ودعم جهود المملكة ورؤيتها تجاه التحول الرقمي واستخدام التقنيات الحديثة في جميع المجالات. Abstract: Despite the great efforts made by Saudi government to avoid construction projects delays, most contemporary studies have shown that the phenomena of construction projects delays are spread with high percentage due to multiple factors, including poor project schedules. With the availability of many digital technologies that could enhance these schedules to achieve projects’ objectives, this is considered the main problem of this research, aiming to study the contemporary trends of digital technologies related to construction schedules and the challenges facing their application to reach a framework to utilize its capabilities to enhance construction schedules. To achieve these goals, the study adopted the analytical descriptive method through an literature-based reviews of the related trends and challenges. The study discussed four of the contemporary trends to enhance schedules and three of the most important challenges they face during application, and concluded the target framework and a number of important results and recommendations to handle the research problem and support the Kingdom\u27s efforts and vision towards digital transformation and the use of modern technologies in all fields

التقنيات الرقمية لإحكام الجداول الزمنية لمشاريع التشييد تحليل مبنى على المراجعات الأدبية للإتجاهات والتحديات Digital Technologies to Enhance Construction Schedules Literature-based Analysis for Trends and Challenges

على الرغم من الجهود الكبيرة التي تبذلها الجهات الحكومية السعودية لتجنب تأخير وتعثر مشاريع التشييد، الا ان أغلب الدراسات المعاصرة أظهرت أنه مازال هناك نسبة كبيرة من المشاريع متأخرة ومتعثرة نتيجة لعوامل متعددة منها ضعف إعداد الجدول الزمني للمشروع، وذلك على الرغم من توافر العديد من التقنيات الرقمية التي يمكنها دعم تطوير وإحكام هذه الجداول لتحقيق أهداف المشاريع، وهو ما يمثل الإشكالية الرئيسية لهذه الدراسة التي تستهدف دراسة الإتجاهات المعاصرة للتقنيات الرقمية ذات العلاقة بالجداول الزمنية لمشاريع التشييد، والتحديات التي تواجه تطبيقها، والوصول إلى إطار لتوظيفها في إحكام الجداول الزمنية لمشاريع التشييد. ولتحقيق هذه الأهداف تبنت الدراسة المنهج البحثي الوصفي التحليلي اعتماداً على المراجعات الأدبية للإتجاهات والتحديات التي تواجه تطبيق هذه التقنيات. وناقشت الدراسة أربعة من الإتجاهات المعاصرة لإحكام الجداول الزمنية وثلاثة من أهم التحديات التي تواجهها وخلصت إلى إطار العمل المستهدف وعدد من النتائج والتوصيات المهمة لمعالجة إشكالية الدراسة ودعم جهود المملكة ورؤيتها تجاه التحول الرقمي واستخدام التقنيات الحديثة في جميع المجالات. Abstract: Despite the great efforts made by Saudi government to avoid construction projects delays, most contemporary studies have shown that the phenomena of construction projects delays are spread with high percentage due to multiple factors, including poor project schedules. With the availability of many digital technologies that could enhance these schedules to achieve projects’ objectives, this is considered the main problem of this research, aiming to study the contemporary trends of digital technologies related to construction schedules and the challenges facing their application to reach a framework to utilize its capabilities to enhance construction schedules. To achieve these goals, the study adopted the analytical descriptive method through an literature-based reviews of the related trends and challenges. The study discussed four of the contemporary trends to enhance schedules and three of the most important challenges they face during application, and concluded the target framework and a number of important results and recommendations to handle the research problem and support the Kingdom\u27s efforts and vision towards digital transformation and the use of modern technologies in all fields