Optimization of received power and SNR for an indoor attocells network in visible light communication

White LEDs Visible Light Communication (VLC) is applied in communication and illumination simultaneously. It provides unrestrained frequency spectrum and a large bandwidth that produces a higher transmission rate and speed in short-range communication. Also, VLC was considered as a promising alternative technology to the radio frequency in the next generation of communication systems. In this paper, the optical attocells configuration and LEDs distribution are proposed for optimizing the received power and Signal-to-Noise Ratio (SNR) in the Line of Sight (LOS) propagation link. Besides that, the trade-off between minimum SNR and received power are investigated. The simulation results showed that the proposed model can save 6.25% of the total transmitted power, and the optical received power versus semi-angle and field of view have with about increased 16.5% and 27.54% respectively. Moreover, the SNR also has 7.4% improvement. Hence, the proposed configuration model has improved the performance of VLC systems and has widen the window for future improvement

A new optimization uniformity for indoor visible light communication systems using optical attocells configuration

The demand for high data rate, capacity, increasing user mobility as well as low power consumption is increasing daily, where it is considered as main the challenges facing the radio frequency (RF) technology. Therefore, an alternative technology called visible light communications (VLC) was adopted to overcome these challenges. This technology is expected to support 5G and beyond due to its high and free frequency offered, as well as robust security. The main problem of this research is, the distribution of a few numbers of optical attocells on the ceiling have caused multiple blind areas in the room, and resulted in nonuniformity distribution. Besides that, employing large numbers of optical attocells has caused a severe ISI, which degrades the system performance, and produced large RMS delay. Therefore, to avoid this problem, a new arrangement of optical attocells, in addition to optimizing the VLC system parameters is proposed. In this research, the proposed arrangement of optical attocells configuration models will improve the uniformity in terms of received power and SNR. The SAAHP, FOV, and CV are used to study the behavior of the two proposed models. The average received power of 2.85 dBm is obtained for the proposed Model Basic 2 that consists of 13 optical attocells, which varies from -0.57 to 4.92 dBm. Moreover, the average SNR of 75.37 dB is obtained for the proposed Model Basic 2, which varies from 68.52 to 79.5 dB. The maximum of received power and SNR is obtained at the center of the room. The better uniformity (CV) of 0.374 and 0.0283 are obtained for the received power and SNR respectively. Additionally, six various modulation techniques are studied to evaluate the proposed models, all modulations produced better BER (≤10−6) at data rate 30 Mbps, while the higher order modulations (L-PPM and M-PAM) produced higher data rate reaching up to 100 Gbps with a BER ≤10−6. This research also investigated an industrial warehouse model with different heights level, where a data rate of 30 Mbps is achieved with acceptable received power and SNR respectively. A BER ≤10−6 is obtained with L-PPM and M-PAM modulation techniques

Performance evaluation of optical attocells configuration in an indoor visible light communication

Visible light communication VLC is deemed as futuristic technology applied for both illumination and data communication due to the low-cost energy consumption, long life expectancy, huge bandwidth, and high security compared to radio frequency RF. Uncovered area, minimum signal-to-noise ratio (SNR) and received power results from the non-uniform distribution of small base stations (i.e. Optical attocells) in the room. In this paper, the researchers propose a new LEDs distribution of five optical attocells configuration model in order to optimize the received power distribution and SNR at the center of the room for indoor VLC system. The optical attocells configuration in terms of received power to fill the uncovered area at the center of the room has been investigated. The simulation results showed that the proposed attocells configuration saved 24.9% of the transmitted power. Besides that, the whole room was covered uniformly. As a result, the received power and SNR are improved

Sedimentation Problems In The Blue Nile Reservoirs And Gezira Scheme

       The development in Sudan is basically dependent on the Blue Nile water. The high sediment load brought by the river during its flood has major influences on the design and operation of the reservoirs built across the river and the schemes irrigated from it. Sediment deposited in reservoirs reduces the useful life of the reservoirs as well as diminishes the benefits from the dam (irrigation and power genera(ion). Large operational costs are incurred every year in dredging the sediment from reservoirs and canal sediment clearance. The sediment monitoring programme launched in 1988 in Gezira Scheme and the Blue Nile, has revealed very important results and answered many vital questions regarding sedimentation in Gezira Scheme. On average 8.5 million tons of sediment enters Gezira scheme every year. More than 97% of this sediment is very fine; therefore, standard methods of sediment exclusion at the intakes will not offer a solution. More than 70% of the sediment can be excluded if the canals gates are closed during the period 20th July to 31st August. This paper reviews the sedimentation problem in the Blue Nile and Gezira Scheme and its management options based on the outcomes of the monitoring programme

Sediment Balance in the Blue Nile in Sudan

The Blue Nile is one of the two main tributaries of the Nile River. It originates in the Ethiopian Plateau. The Blue Nile water plays an important role in the economic development of Sudan in terms of irrigated agricultural development and hydropower generation. The average annual flow of the Blue Nile is 50 billion cubic meters, 80% of it occurs during the flood season (July – October). During the flood season the river brings down large amounts of sediment estimated as 146 million tons per year. The sediment material originates mainly from heavy erosion in the upper catchment area in Ethiopia. The Blue Nile system within Sudan includes two reservoirs, Roseires and Sennar, and two tributaries, viz. Dinder and Rahad. Sennar and Roseires reservoirs have already lost 65% and 34% of their initial storage capacities due to sedimentation, respectively. The Blue Nile sediment in Sudan is monitored at a number of stations scattered along its length. The sediment concentrations vary during the flood season and from year to year. The sediment load is also variable along the river length due to deposition in the river channel, trapping in the reservoirs, diversion to irrigated schemes and inputs from tributaries. In this paper the sediment trap efficiency of each reservoir is calculated using bathymetric survey data. The current trap efficiency of Roseires and Sennar reservoirs is found to be 17% and 5%, respectively. The average annual sediment diverted to Gezira Scheme is 8.5x106 tons. The spatial sediment distribution along the Blue Nile is given at key river nodes. Upstream and downstream each reservoir and at Gezira canals’ off-takes and at its confluence with the White Nile. The annual average sediment contribution of the Blue Nile to the Main Nile is found to be 143x106 tons. The paper also reviews the main characteristics of the Blue Nile sediment that affect its transport and deposition. &nbsp

Teaching Procedures and Skills in Medical Schools: Gaps, Weakness, and Challenges

There is deficiency and gaps among medical graduates in performing certain procedures and skills. Till recent years, some school used an apprenticeship model for teaching procedures. The way of teaching skills should be revised and reinforced. Medical schools showed adopt formal curricula based training for teaching procedure. In this letter, we would like to highlight the challenges and weakness in teaching procedure for undergraduates medical students. 

Gunshot Injuries: Patterns, Presentations, and Outcomes of Civilian Hospital Experiences in a Developing Country Setting

Background: Gunshot injuries are considered a health burden as well as one of the intricate emergencies in civilian medical practice. In this study, we aim to determine the pattern of presentation and management outcome in a general hospital setting in a sub-Saharan African country.Methods: This is a retrospective, hospital-based study conducted between January 2015 and December 2019 in a general teaching hospital to review the clinical presentation and management outcome of gunshot injuries. All patients’ records were reviewed during the study period.Results: The total number of patients involved in the study was 157 with 83% male predominant. About 50% were from the age group 20–29 years that were most affected. The commonest anatomical site affected in the study was the lower limb (41.4%) and upper limb (22.9%), and most of the patients had been diagnosed with limb fractures (49.7%) and soft tissue injuries (28.7%). Wound debridement is the commonest procedure performed for 91 (58.0%) patients. The site of the pullet has a significant relation to the management outcome with a P-value of 0.002. Additionally, about 45% (72 patients) have stayed more than 20 days and it was affected significantly by the types of treatment provided, which has a significant relation to a hospital stay with a P-value of 0.00.Conclusion: Most of the patients in this study were young males. Upper and lower limb fractures were the most common presentations. Wound debridement, bone fixation, and laparotomy were the most common treatments with significant success rates, despite prolonged hospital stays

Graduates Perception towards Instructional Methods of Emergency Medicine: Affecting Their Self-confidence in Emergency Departments

Background: Teaching emergencies has the ability to provide medical students with animportant knowledge and skills. In this study, we assessed the perception of Faculty of medicine, University of Gezira graduates regarding instructional methods of emergencies and their performance in emergency departments. Materials and Methods: This is a cross-sectional survey, which was conducted among newly graduated doctors, during their internship rotation. We assessed the graduateperception about instructional methods of teaching EM during medical school and how they deal with emergencies. Likert’s scale of five points was used for assessment of the graduate response. This data was used for a correlation analysis. Result: Ninety three graduates were enrolled. Male doctors’ numbers was 41(44%). Most of the graduated doctors agreed that clinical round and practical session in teaching emergency are useful among 80(86%) and 74(79.6%) of them respectively. Less number of graduated students 45 (48.4%) and 43 (36.6%) agreed that Problem-based learning and Seminar are useful in teaching emergency. Numbers of graduates who feel competence to assess and diagnose patients, request a relevant investigation, and can put a treatment plan and start the managements are 60(68.8%), 76(81.8%) and 61 (65.6%) respectively. Conclusion: There are some strength and weakness in emergency teaching during medical school which affects their self-confidence when dealing with emergencies

Two-Element MIMO Crack Finger Microstrip Antenna for Hand-Held Devices

in this paper, we studied the effect of mutual coupling between MIMO antennas and a method is proposed to reduce it between 2-element micro-strip MIMO antenna systems for handheld devices. To reduce mutual coupling between the MIMO antenna element a separate ground plane is designed and the two elements are positioned on the edges of the 2-element MIMO antenna system. A novel idea defined in order to reduce mutual coupling between the closely spaced micro-strip patch elements is adding finger shapes at the edge of each patch antenna to design a new crack finger micro-strip the fingers generate capacitance in between which improved the matching between the patch and the Micro-strip transmission line as well as the mutual coupling reduced from -25 dB to -40 dB. The simulation results showed that the 2-element MIMO system covered the frequency of 2.4 GHz, and the gain and directivity are 6.149 dB and 4.399All the simulations were carried out in CST Microwave Studio