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Visible light communication (VLC) has been proposed as a promising and efficient solution to indoor ubiquitous broadband connectivity. In this paper, non-orthogonal multiple access, which has been recently introduced as an effective scheme for fifth generation (5G) wireless networks, is considered in the context of VLC systems under different channel uncertainty models. To this end, we first derive a novel closed-form expression for the bit-error-rate (BER) under perfect channel state information (CSI). Capitalizing on this, we then quantify the effect of noisy and outdated CSI by deriving a simple and accurate approximation for the former and a tight upper bound for the latter. The offered results are corroborated by respective results from extensive Monte Carlo simulations and assist in developing useful insights on the effect of imperfect CSI knowledge on the overall system performance. Furthermore, it was shown that while noisy CSI leads to slight degradation in the BER performance, outdated CSI can cause considerable performance degradation, if the order of the users’ channel gains change due to the involved mobility.

This paper presents two architectures for prototyping an advanced carrier frequency offset (CFO) estimation technique for OFDM systems on field programmable gate array (FPGA). The parallel stream architecture (PSA) exploits the FPGA parallelism while the multiplexed stream architecture (MSA) employs multiplexing for more efficient hardware implementation. The dual-mode of operation for the proposed architectures has been proposed to achieve optimum performance depending on channel conditions. The proposed architectures with different implementation alternatives have been simulated and verified for FPGA implementation using the Xilinx’s DSP design flow. The estimation accuracy and the resource utilization for the proposed architectures have been evaluated. The prototyping results showed that MSA allows for more resource efficient implementation, where a single FFT core can be shared between parallel streams compared with PSA.

This work presents an experimental study on both short-term and long-term deflections for a period more than seven months of reinforced high and normal strength reinforced concrete two-way flat plate panels. Four reinforced concrete panels with dimensions of (960×960×50) mm were investigated with simply supported edges. Concrete cube strength is about 75 MPa for HSC panels, and 30 MPa for the control panel. Sustain load kept along the entire test period and at the end, the loads is removed and the recoverable deflection was measured. It’s been concluded that the rate of increase in HSC panels’ long time deflection is less than that of NSC panels, also the long-term deflection is highly reduced by increasing the compressive strength of concrete and the long term deflection reduced about 20% when compressive strength increased from 25 to 65 MPa.

This paper investigates the relationship between the ultrasonic pulse velocity (UPV) and the compressive strength of concrete. The specimens used in the study were made of concrete with varied aggregate contents from 1000 to 1400 kg/m3. The specimens were made and tested at the Hawler Construction Laboratories (HCLabs) in Erbil, Kurdistan Region of Iraq. The UPV measurement and compressive strength tests were carried out at the concrete age of 28 days. The experimental results show that the relationship between UPV and the compressive strength of concrete is significantly influenced by the coarse aggregate content. Relationships are established for the range of contents of coarse aggregates and discussed.

This research aims to find out the extent of realizing the significance of electronic disclosure of financial reporting over studying disclosure concept according to the accounting literature historically. A total of 30 hard copies questionnaire have been distributed on research sample. The research applied descriptive analytical approach through studying content, percentage, frequency, mean and T-test in order to fulfil the research results. The Study concluded the banks operated in Erbil Province has a luck of realization about electronic disclosure of financial reporting and they do not have electronic disclosure system, due to the poor experience, skills and the absence of clear policies of banks management. The researchers recommended banks operated in Erbil Province to employ electronic disclosure system to overcome the obstacles facing traditional banks, as well as to follow globalization trends in this regards which may improve their performance. This can be done by opening courses and seminars in the area of disclosure and providing accounting information through websites to overcome difficulties and problems, in addition to address them.

The hallmark of diagnosing classical chronic myelogenous leukemia (CML) is the identification of Philadelphia (Ph) chromosome (Chr). However, some CML cases show additional structural/numerical chromosomal abnormalities involving either Ph Chr or more frequently other Chrs. Genetic alterations sparing Ph Chr are commonly called “additional chromosomal abnormalities (ACAs)” which have been extensively analyzed in recent large studies. In contrast, the presence of additional genetic abnormalities in Ph Chr has been anecdotally reported with an ambiguity of their impact on treatment response. In our case, we report a newly diagnosed CML patient with the rarest additional chromosomal aberration affecting Ph Chr which has revealed an optimal response over a period of 2 years of follow-up. This report underlines the importance of re-examining CML cases for any ACAs, especially those occurring in Ph Chr, which might be overlooked easily. Moreover, their possible role in disease prognostication should be sought, as well.

Background: Systemic lupus erythematosus (SLE) is an autoimmune disease where the body's immune system attacks its own healthy tissue. It can affect many organs such as skin, joints, brain, kidneys and other organs. Objectives: to evaluate the knowledge toward Systemic Lupus Erythematosus (SLE) among citizens in Al-Dammam city. Methods: a questionnaire-based quantitative cross-sectional study which focuses on determining the knowledge of Systemic lupus erythematosus in Al-Dammam city. Results: 240 participants filled the surveys, 130 participants (54%) have no idea about SLE. The majority of respondents had no clear idea regarding treatment and complications of the disease. 32% respondents had idea that SLE is more prevalent among females. In fact, this disorder is reported more prevalent in women. Conclusion: this study indicated that the public have low awareness with some misconception regarding the SLE. The awareness campaigns are needed to increase the awareness about SLE which will be helpful to educate the public about its symptoms and methods of treatments.

This experimental study was done to quantify the mechanical strength resulting from the presence of limestone powder as partial replacement of cement in the mixture of mortar and concrete. Mortars and concretes were made by using limestone powder with various replacement levels of the ordinary Portland cement (OPC) by mass: 0%, 5%, 10%, 15%, 20%, 25%, and 30%. Samples of mortar and concrete cubes, concrete cylinders and prisms were made to measure the limestone mortar compressive strength, and the limestone concrete compressive, splitting-tensile, and flexural strengths with various replacement levels of limestone. The development of strengths was studied and the modulus of elasticity of limestone concrete was also measured. The experimental results show a reduction in the mechanical properties of limestone concrete with the increase of limestone powder replacement level. Some experimental results obtained by other researchers have been compared with this study and discussed.

This paper presents an adaptive approach to address the two main problems associated with the time varying Doppler shift, the first being the acceleration effects on the cyclic-prefix (CP) correlation and the second, the effect of a sudden change in the velocity direction between packets on the entire orthogonal frequency division multiplexing (OFDM) symbols. In addition, this paper considers the residual Doppler shift or carrier frequency offset (CFO) that was estimated iteratively within a range according to a design based on the sub-carrier spacing using pilots, which are basically utilized for the purpose of channel estimation. Furthermore, the proposed algorithm adopts three estimations of the symbol timing offset. These estimations are centroid-based localization over an anticipated CP window, first order expectation and autocorrelation of the received CP with its replica. Subsequently, a penalization algorithm is applied in order to drop the anomalous parameter among them. Therefore, the consequences of the inflection point that accompanies the abrupt change in the velocity are mitigated and a reliable time varying Doppler shift is obtained. This Doppler shift is fine tuned in an iterative manner. Compared with the block-based Doppler compensation approach, the proposed technique works with variable speed during packet duration. In addition, it exploits the available bandwidth more efficiently by utilizing a single preamble of linear-frequency-modulation (LFM) to detect the start of the packet. The proposed receiver was evaluated through simulations and sea trials conducted over 500m and 1000m channel ranges. In simulations, a model was designed to imitate the time varying Doppler shift with two scenarios (expansion/compression) in combination with a various multipath delay spread. The simulation results confirm that the proposed system accommodates an acceleration up to ? 1 m/s2 during the packet time.

In this paper, we introduce a Quantized Cramer Rao Bound (Q-CRB) method, which adapts the use of the CRB to handle grid-based localization algorithms with certain constraints, such as localization boundaries. In addition, we derive a threshold granularity level which identifies where the CRB can be appropriately applied to this type of algorithm. Moreover, the derived threshold value allows the users of grid-based LSE techniques to probably avoid some unnecessary complexities associated with using high grid resolutions. To examine the feasibility of the new proposed bound, the grid-based least square estimation (LSE) technique was implemented. The Q-CRB was used to evaluate the performance of the LSE method under extensive simulation scenarios. The results show that the Q-CRB provided a tight bound in the sense that the Q-CRB can characterize the behaviour of location errors of the LSE technique at various system parameters, e.g. granularity levels, measurement accuracies, and in the presence or absence of localization boundaries.

The explosive growth of connected devices and the increasing number of broadband users have led to an unprecedented growth in traffic demand. To this effect, the next generation wireless systems are envisioned to meet this growth and offer a potential data rate of 10 Gbps or more. In this context, an attractive solution to the current spectrum crunch issue is to exploit the visible light spectrum for the realization of high-speed commutation systems. However, this requires solutions to certain challenges relating to visible light communications (VLC), such as the stringent requirements of VLC-based intensity modulation and direct detection (IM/DD), which require signals to be real and unipolar. The present work proposes a novel power-domain multiplexing based optical asymmetric modulation (OAM) scheme for indoor VLC systems, which is particularly adapted to transmit high-order modulation signals using linear real and unipolar constellations that fit into the restrictions of IM/DD systems. It is shown that the proposed scheme provides improved system performance that outperforms alternative modulation schemes, at no extra complexity.

The explosive growth of connected devices and the increasing number of broadband users have led to an unprecedented growth in traffic demand. To this effect, the next generation wireless systems are envisioned to meet this growth and offer a potential data rate of 10 Gbps or more. In this context, an attractive solution to the current spectrum crunch issue is to exploit the visible light spectrum for the realization of high-speed commutation systems. However, this requires solutions to certain challenges relating to visible light communications (VLC), such as the stringent requirements of VLC-based intensity modulation and direct detection (IM/DD), which require signals to be real and unipolar. The present work proposes a novel power-domain multiplexing based optical asymmetric modulation (OAM) scheme for indoor VLC systems, which is particularly adapted to transmit high-order modulation signals using linear real and unipolar constellations that fit into the restrictions of IM/DD systems. It is shown that the proposed scheme provides improved system performance that outperforms alternative modulation schemes, at no extra complexity.

In-phase/quadrature-phase Imbalance (IQI) is considered a major performance-limiting impairment in direct-conversion transceivers. Its effects become even more pronounced at higher carrier frequencies such as the millimeter-wave frequency bands considered for 5G systems. In this work, we quantify the effects of IQI on the performance of different modulations under multipath fading channels. This is realized by developing a comprehensive framework for the symbol error rate (SER) analysis of coherent phase shift keying (PSK), noncoherent differential phase shift keying (DPSK) and noncoherent frequency shift keying (FSK) under IQI effects. In this context, the moment generating function of the signal-to-interference-plus-noise-ratio is first derived for single-carrier systems suffering from transmitter (TX) IQI only, receiver (RX) IQI only and joint TX/RX IQI. Capitalizing on this, we derive analytic expressions for the SER of the different modulation schemes considered. These expressions are corroborated with simulation results and they provide insights into the dependence of IQI on the system parameters. We further demonstrate that, while in some cases, IQI can cause a slight degradation of the SER performance and, hence, it can be neglected, in other cases it should be compensated in order to achieve a reliable communication link. acceptedVersion

Non-orthogonal multiple access (NOMA) has been recently proposed as a viable technology that has the potential to improve the spectral efficiency of fifth generation (5G) wireless networks and beyond. However, in practical communication scenarios, transceiver architectures inevitably suffer from radio-frequency (RF) front-end related impairments that can lead to non-negligible degradation of the overall system performance. In this context, in-phase/quadrature-phase imbalance (IQI) constitutes a major impairment in direct-conversion transceivers. Based on this, the present contribution quantifies the effects of IQI on the performance of NOMA based systems under multipath fading conditions. This is realized by first deriving novel analytic expressions for the signal-to-interference-plus-noise ratio and the outage probability of NOMA systems subject to IQI at the transmitter and/or the receiver sites. Capitalizing on these results, we demonstrate that the effects of IQI differ considerably between the different NOMA users and depending on the considered system's parameters.

Non-orthogonal multiple access (NOMA) has been recently proposed as a viable technology that can potentially improve the spectral efficiency of fifth generation (5G) wireless networks and beyond. However, in practical communication scenarios, transceiver architectures inevitably suffer from radio-frequency (RF) front-end related impairments that can lead to degradation of the overall system performance, with in-phase/quadrature-phase imbalance (IQI) constituting a major impairment in direct-conversion transceivers. In the present work, we quantify the effects of joint transmitter/receiver IQI on the performance of NOMA based multi-carrier (MC) systems under multipath fading conditions. Furthermore, we derive the asymptotic diversity order of the considered MC NOMA set up. Capitalizing on these results, we demonstrate that the effects of IQI differ considerably among NOMA users and depend on the underlying system parameters. For example, it is shown that the first sorted user appears more robust to IQI, which indicates that higher order users are more sensitive to the considered non-negligible impairment.

The proliferation of mobile Internet and connected\ud devices, offering a variety of services at different levels of\ud performance, represents a major challenge for the fifth generation\ud wireless networks and beyond. This requires a paradigm shift\ud towards the development of key enabling techniques for the next\ud generation wireless networks. In this respect, visible light communication\ud (VLC) has recently emerged as a new communication\ud paradigm that is capable of providing ubiquitous connectivity\ud by complementing radio frequency communications. One of the\ud main challenges of VLC systems, however, is the low modulation\ud bandwidth of the light-emitting-diodes, which is in the megahertz\ud range. This article presents a promising technology, referred to\ud as "optical- non-orthogonal multiple access (O-NOMA)", which\ud is envisioned to address the key challenges in the next generation\ud of wireless networks. We provide a detailed overview and analysis\ud of the state-of-the-art integration of O-NOMA in VLC networks.\ud Furthermore, we provide insights on the potential opportunities\ud and challenges as well as some open research problems that\ud are envisioned to pave the way for the future design and\ud implementation of O-NOMA in VLC systems.

Sustainability is a vital and effective contribution to control the use of natural resources in a scientific and accurate manner without wasting work and preserving these resources to meet the current and future needs of societies. The goal of achieving sustainability in construction projects requires procedures that start from design through the use of recyclable materials or reuse. To ensure this, the standards must be defined and implemented in a precise and practical manner. Sustainability criteria for construction projects are organized in sets of questions to be answered by the construction projects officials. These questions take focus on the main building construction steps. The checklist considers weighting the questions according to their level of effect on the sustainability measures. In the current work, 22 construction projects were evaluated in the province of Erbil / Kurdistan region of Iraq through the inclusion of a set of sustainability criteria in the form of questions addressed to the engineers and project managers. The results were analyzed to determine the implementation approaches of the sustainability criteria. Economic, social and environmental factors were included and construction steps were weighed in the questions of the checklist according to these factors. The results confirm the effectiveness of the proposed checklist for estimating a sustainability score for construction projects. The results show high variations in applying sustainability measures in the various construction steps in all of the construction projects. The reasons are due to the absence or weakness of binding laws and the lack of adoption of comprehensive designs based on the pillars of sustainability.

In the current work, 22 construction projects were evaluated in the province of Erbil / Kurdistan region of Iraq through the inclusion of a set of sustainability criteria in the form of questions addressed to the engineers and project managers. The results were analyzed to determine the implementation approaches of the sustainability criteria. Economic, social and environmental factors were included and construction steps were weighed in the questions of the checklist, developed in a companion paper, according to these factors. The results confirm the effectiveness of the proposed checklist for estimating a sustainability score for construction projects. In average, the score of approximately 54% of applying the sustainability measures was obtained. The results show high variations in applying sustainability measures in the various construction steps in all of the construction projects. The reasons are due to the absence or weakness of binding laws, absence of sustainability requirements as a topic in civil engineering curricula, and the lack of adoption of comprehensive designs based on the pillars of sustainability.

Sleep deprivation (SD) is associated with cognitive deficits. It was found to affect the hippocampus region of the brain by impairing memory formation. This impairment is suggested to be caused by elevation in oxidative stress in the body, including the brain during SD. It was hypothesized that the methanolic extract of the fruits of Arbutus andrachne L. (Ericaceae) will prevent chronic SD-induced impairment of hippocampal memory via its antioxidative properties. The methanolic extract of the fruits of A. andrachne was evaluated for its beneficial properties to reverse SD-induced cognitive impairment in rats. Animals were sleep deprived for 8�weeks using a multiple platform model. The extract was administered i.p. at three doses (50, 200, and 500�mg/kg). Behavioral studies were conducted to test the spatial learning and memory using radial arm water maze (RAWM). In addition, the hippocampus was dissected to analyze the following oxidative stress markers: glutathione (GSH), oxidized glutathione (GSSG), GSH/GSSG, glutathione peroxidase (GPx), and catalase. Chronic SD impaired short- and long-term memories (P�

Novel analytic solutions are derived for integrals that involve the generalized Marcum $Q$ -function, exponential functions and arbitrary powers. Simple closed-form expressions are also derived for specific cases of the generic integrals. The offered expressions are both convenient and versatile, which is particularly useful in applications relating to natural sciences and engineering, including wireless communications and signal processing. To this end, they are employed in the derivation of the average probability of detection in energy detection of unknown signals over multipath fading channels as well as of the channel capacity with fixed rate and channel inversion in the case of correlated multipath fading and switched diversity.

Dynamic power allocation and power splitting, in a multicarrier two-hop link with a wireless powered relay, is investigated. We first formulate the corresponding optimization problem, which consists of the joint optimization -in terms of achievable rate- of, 1) the dynamic power allocation among multiple channels and, 2) the selection of the power splitting ratio between information processing and energy harvesting at the relay, when amplify-and-forward is applied. This is a non-convex optimization problem, which is mapped to a convex one and optimally solved using one-dimensional search and dual decomposition, while a suboptimal efficient iterative method is also proposed. Simulations reveal a significant increase in the throughput, when comparing the proposed approach with two alternative power allocation schemes, while they verify the effectiveness of the fast-converging iterative solution.

The rapidly increasing global demand for energy combined with the environmental impact of fossil fuels has spurred the search for alternative sources of clean energy. One promising approach is to convert solar energy into hydrogen fuel using photoelectrochemical cells. However, the semiconducting photoelectrodes used in these cells typically have low efficiencies and/or stabilities. Here we show that a silicon-based photocathode with a capping epitaxial oxide layer can provide efficient and stable hydrogen production from water. In particular, a thin epitaxial layer of strontium titanate (SrTiO3) was grown directly on Si(001) by molecular beam epitaxy. Photogenerated electrons can be transported easily through this layer because of the conduction-band alignment and lattice match between single-crystalline SrTiO3 and silicon. The approach was used to create a metal–insulator–semiconductor photocathode that, under a broad-spectrum illumination at 100 mW cm−2, exhibits a maximum photocurrent density of 35 mA cm−2 and an open circuit potential of 450 mV; there was no observable decrease in performance after 35 hours of operation in 0.5 M H2SO4. The performance of the photocathode was also found to be highly dependent on the size and spacing of the structured metal catalyst. Therefore, mesh-like Ti/Pt nanostructured catalysts were created using a nanosphere lithography lift-off process and an applied-bias photon-to-current efficiency of 4.9% was achieved. A silicon-based photocathode with an epitaxial strontium titanate protection layer and a mesh-like nanostructured catalyst can provide an applied bias photon-to-current efficiency of 4.9% for water reduction.

Coherent detection requires exact knowledge of the channel state information, which is often a challenging task in demanding practical applications. Based on this, non-coherent detection of differentially modulated signals can be considered as an alternative method. The present paper investigates the effects of in-phase/quadrature-phase imbalance (IQI), which are known to degrade the performance of wireless communication systems. Specifically, we evaluate the effects of IQI on the bit error rate (BER) performance of differential quadrature phase shift keying (dQPSK) for ideal receiver (RX) with transmitter (TX) IQI, ideal TX with RX IQI and joint TX/RX IQI. Explicit analytic expressions are derived for the BER of both single-carrier and multi-carrier systems suffering from IQI at the TX and/or RX. Extensive Monte-Carlo simulation as well as offered analytic results show that realistic TX/RX IQI values can degrade the corresponding BER by over 30%. Likewise, it is shown that the detrimental effects of IQI are more considerable on DQPSK than on QPSK.

Highlights • We present 3 cases of late distal nerve transfer to deltoid. • The outcome was excellent despite the delay from time of injury. • This was explained by the presence of partial muscle innervation., Introduction Our literature review did not reveal any study on the results of triceps to deltoid nerve transfer done as a secondary procedure after an unsatisfactory primary intraplexus neurotization of the posterior division of the upper trunk. Presentation of cases We report on three adults with C5-C6 brachial plexus injury who had an unsatisfactory deltoid function following primary intraplexus neurotization. Patients presented to our clinic late (14–16 months after injury). All patients had poor shoulder abduction ( 150°) in all patients. Discussion The primary surgery in our patients acted as a “baby-sitter” procedure; explaining the good results of the late secondary distal nerve transfer. Conclusion Good results may be obtained from a late distal nerve transfer for the deltoid muscle as long as there is partial innervation of the muscle.

This research presents an experimental program for investigating punching shear strength of slabs, consisting of 27 high and normal strength concrete slabs. The test data from the experiment are analyzed and divided into three series primarily concerned with the effects of three variables on the punching strength of high-strength (HS) concrete slabs: the concrete strength, the slab depth and the column size and shape. The tests showed that the critical perimeter is located at a distance (1.5d) from the load area.

This paper studies different secrecy rate optimization problems for a multiple-input–multiple-output (MIMO) secrecy channel. In particular, we consider a scenario where a communication through a MIMO channel is overheard by a multiple-antenna eavesdropper. In this secrecy network, we first investigate two secrecy rate optimization problems: 1) power minimization and 2) secrecy rate maximization. These optimization problems are not convex due to the nonconvex secrecy rate constraint. However, by approximating this secrecy rate constraint based on Taylor series expansion, we propose iterative algorithms to solve these secrecy rate optimization problems. In addition, we provide the convergence analysis for the proposed algorithms. These iterative optimization approaches are developed under the assumption that the transmitter has perfect channel state information. However, there are practical difficulties in having perfect channel state information at the transmitter. Hence, robust secrecy rate optimization techniques based on the worst-case secrecy rate are considered by incorporating channel uncertainties. By exploiting the S-Procedure , we show that these robust optimization problems can be formulated into semidefinite programming at low signal-to-noise ratios (SNRs). Simulation results have been provided to validate the convergence of the proposed algorithms. In addition, numerical results show that the proposed robust optimization techniques outperform the nonrobust schemes in terms of the worst-case secrecy rates and the achieved secrecy rates.

Reactive powder concrete, RPC, is an ultra-high strength and high ductility cementitious composite with advanced mechanical and physical properties. RPC is composed of very fine powders (cement, sand, quartz powder and silica fume), steel fibers (optional) and superplasticizer. A basic principle, which was presented by the first developers of RPC, is to eliminate the coarse aggregate in mixture to enhance homogeneity. The main purpose of the present investigation is to modify RPC by including natural graded coarse aggregate in the mixture in different approaches. The investigation was devoted to monitor the strength development, total absorption and permeability of RPC after exposure to two types of oil products, kerosene and gas oil, up to 180 days. The current results showed that eliminating coarse aggregate as a principle could be gone-beyond. The better way for including coarse aggregate in RPC was to replace the fine sand and the most useful FA/A ratio is expected to be within the range of 0 - 25 % by weight. This range was found to create an optimum situation between strength and absorption for kerosene and gas oil exposures. It is not recommended to include the coarse aggregate in RPC mixtures as a replacement to the binder specially when dealing with oil products storage.