Channel Estimation and Prediction Based Adaptive Wireless Communication Systems

Wireless channels are typically much more noisy than wired links and subjected to fading due to multipath propagation which result in ISI and hence high error rate. Adaptive modulation is a powerful technique to improve the tradeoff between spectral efficiency and Bit Error Rate (BER). In order to adjust the transmission rate, channel state information (CSI) is required at the transmitter side.In this paper the performance enhancement of using linear prediction along with channel estimation to track the channel variations and adaptive modulation were examined. The simulation results shows that the channel estimation is sufficient for low Doppler frequency shifts (<30 Hz), while channel prediction is much more suited at high Doppler shifts with same SNR and target BER=10-4. It was shown that the performance at higher Doppler frequency shifts (<30Hz) was improved by more than 2dB over channel estimation at target BER=10-4 and 32QAM constellation used

WLAN Integrated with GPRS Network Securely

In this paper a WLAN network that accesses the Internet through a GPRS network was implemented and tested. The proposed network is managed by the Linux based server. Because of the limited facilities of GPRS such as dynamic IP addressing besides to its limited bandwidth a number of techniques are implemented to overcome these limitations.Dynamic Host Configuration Protocol (DHCP) server was added to provide a single central control for all TCP/IP resources. Squid Proxy was added to provide caching of the redundant accessed Web content to reduce the Internet bandwidth usage and speeding up the clients download time. Network Address Translation (NAT) service was configured to share one IP address among several different systems. In order to accomplish a secure channel to exchange data between two network devices, the Secure Shell (SSH) protocol was added. The first test shows that the data transfer rate at different time intervals of the day found to be an average of 10.95 Kbps for uploading and 13.7 Kbps for downloading and the second test shows that the network performance improved when squid proxy cache was used. The data rate found to be 143.3 Kbps average for uploading rate and 376.6 Kbps average for downloading rate

Antitumor and structure antioxidant activity relationship of Colchicine on Ehrlich ascites Carcinoma (EAC) in Female Mice

Colchicine has been reported to play important roles in hepatoprotection, anti-inflammation in vitro anti cancer activity. The present study was initiated to evaluate antioxidant and anti-cancer effects of colchicine (10µg/mice, i.p.) in mice after subcutaneous implantation of ehrlich ascites carcinoma (EAC) for 21 days. On the 22th day, the mice were sacrificed for the estimation of tumor growth, and biochemical parameters (glucose, insulin, alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), lipid peroxides (TBARS), protein thiols (Pr-SHs), reduced glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), total cholesterol (TC), triglycerides (TG), HDL-C, LDL-C, 17β-estradiol and progesterone). The results of this study showed that administration of colchicine and 5-Flourouracil individually for 21 days to the carcinoma induced mice demonstrated a significant (P&lt;0.01) decrease in tumor weight and a significant (P&lt;0.01) improvement in biochemical parameters and life span  compared to the EAC control mice. In addition, the results clearly suggest that colchicine induced antioxidant activity on experimental EAC control mice

Production and Characterization of Pectic Enzymes of Xanthomonas campestris pv. sesami

إنتاج ودراسة خصائص الإنزيمات البكتينية للبكتيريا Xanthomonas campestris pv. sesami &nbsp; ملخص الدراسة &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;البكتيريا&nbsp; Xanthomonas campestris pv. sesami ، هي المسبب لمرض تبقع أوراق نبات السمسم. الأنزيمات البكتينية التي تنتج بواسطة العديد من البكتيريا الممــرضة للنبات اتضـح أنها تلعب دوراً هاماً في عمــلية الأمراض. هنالك ثلاث أنواع رئيـسـية من الإنزيمات البكــتينية (بوليجلاكتيورونيز، PG وبوليجلاكتيورونيت ترانس - امنيز، PTE و بكتين ميثايل - اٍستريز، PME). هـدف هذا البحث على دراسة قدرة البكتيريا، X.&nbsp; campestris pv. sesami&nbsp; على إنتاج الإنزيمات البكتينية المختلفة. استخدم في هذه الدراسة وسط غذائي من الأملاح مضافاً إليه مواد بكتينية مختلفة كمصدر للكربون. الإنزيمات المنتجة تمت دراسة خصائصها باستخدام اختبارات محددة. أوضحت النتائج أن البكتيريا كانت قادرة إنتاج الإنزيم بوليجلاكتيورونيت ترانس - اٍمنيز ((PTE فقط ولم تنتج الانزيم بكتين ميثايل - اٍستريز، PME)). أشارت النتائج الى أن ملح بولي بكتات الصوديوم وحمض البولي جلاكتيورونيك&nbsp; هي الأفضل لإنتاج هذا الإنزيم حيث أعطت&nbsp; 9 .26 و 19.8 وحدات لزوجة إنزيمية، على التوالي. . كان أعلى إنتاج للإنزيم في اليوم السادس (9.3 وحدات لزوجة)&nbsp; ثم انخفض الإنتاج مع زيادة فترة التحضين. اختبار تأثير درجة الأس الهيدروجيني أوضح أن الدرجة المثلى لنشاط&nbsp; الإنزيم كانت 9.0. أظهرت دراسة اختبار تاثيز ايونات لمعادن مختلفة على نشاط الانزيم أن أيونات الكالسيوم هي التي أعطت اكبر نشاط 12.2&nbsp; وحدة لزوجة. وعند اختبار تراكيز مختلفة من&nbsp; ايونات الكالسيوم ووجد ان اعلى نشاط كان على التركيز&nbsp; 50 ملج / مل حيث أعطى 18.0 وحدة لزوجة. توصي الدراسة على اختبار قدرة البكتيريا على انتاج إنزيمات السليولوز وشبه السليولوز والتي لها دور ايضاً في عملية الاٍمراض.&nbsp; &nbsp; &nbsp; &nbsp;The bacterium Xanthomonas campestris pv. sesami, is the causal organism of the leaf spot disease (Marad eldum) in sesame plants. Pectic enzymes which were reported to be produced by many plant pathogenic bacteria,&nbsp; were found to play an important role in pathogenesis. There are three main types of pectic enzymes (Polygalacturonase, PG, Polygalacturonate trans-eliminase PTE and Pectin methylesterase PME). The present study was conducted to investigate the capacity of the bacterium X. campestris pv. sesami,&nbsp; to produce the different types of pectic enzymes. A salt medium supplemented with different pectic materials as carbon sources were tested for the production of the enzymes. The produced enzymes were characterized using different selective tests, both the viscosity and reducing group methods were used to measure the enzyme activity. The results showed that no pectin methylestrease (PME) was produced and only the Polygalacturonase trans-eliminase (PTE) was produced by the bacterium. Sodium polypectate and polygalacturonic acid were found as the best substrates giving 26.9 and 19.8 viscosity enzyme units, respectively. The enzyme activity was maximum at the 6th day (9.3 viscosity units), then the activity was decreasing with further incubation time. The test of the effect of the pH indicated that the&nbsp; pH optimum of the enzyme activity was at pH 9.0. The effects of different metallic ions to the enzyme activity showed that,= a higher activity was found with Ca++ which gave 12.2 viscosity&nbsp;&nbsp;&nbsp; units. When different concentrations of Ca++ were tested, the maximum activity of the enzyme was found at 50 mg/ ml concentration, which gave 18.0 viscosity units. It could be recommended that the tested bacterium should be investigated for the production of the cellulases and hemi-cellulases which also have a role in the pathogenesis process

Effects of Whole Blood Storage on Hematological Parameters of Sudanese Donors attending Central Blood Bank

Background: During storage of blood several hematological and biochemical changes take place that may affect viability of blood cells and other components. In Sudan (to our knowledge) there is no enough information about these changes and there are some gaps in the studies that have been conducted, it did not include all hematological parameters, thus the aim of the present study is to study the various hematological changes occurring in stored whole blood.&nbsp; Methods: This is cross-sectional study conducted at Central Blood Bank, Khartoum state. The study conducted in the period from October 2019 to February 2020, included 100 Sudanese adults donors at defined age group (18-48). The Complete Blood Count (CBC) was performed on it immediately at the time of collection, and this was considered as control, then CBC performed at 1,2,3,4 weeks using automated cell count (Sysmex KY21N).&nbsp; Results: In the first and second weeks there were insignificant changes in all hematological parameters except for platelets, there was a significant decrease started from first week (2.086 vs 3.286; p value =.005) compared to the control, while in third and fourth weeks all changes that occurred with a significant decrease, except for the MCV, which was significant increase in fourth week (90.725 vs. 87.846; p value =.001) compared to the control.&nbsp; Conclusions: All hematological parameters that evaluated above affected by storage, but platelets are more affected which have significant decrease in Day 7.&nbsp

Global convergence of a modified RMIL+ nonlinear conjugate gradient method with strong wolfe

Nonlinear conjugate gradient (CG) methods are extensively used as an important technique for addressing large-scale unconstrained optimization problems which are arise in many aspects of science, engineering, and economics. That is due to their simplicity, convergence properties, and low memory requirements. To generate a new approximation solution in each iteration, the CG methods usually implement under the strong Wolfe line search. For good performance, many studies have been carried out to modify well-known CG methods. In this paper, we did some modifications on one of CG method called RMIL+ in order to obtain a new CG method possesses the sufficient descent property and the global convergence under strong Wolfe line search. The numerical results demonstrate that the suggested method outperforms other CG methods

Early age strength development of fly ash mixes as affected by temperature

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A modified type of Fletcher-Reeves conjugate gradient method with its global convergence

The conjugate gradient methods are one of the most important techniques used to address problems involving minimization or maximization, especially nonlinear optimization problems with no constraints at all. That is because of their simplicity and low memory needed. They can be applied in many areas, such as economics, engineering, neural networks, image restoration, machine learning, and deep learning. The convergence of Fletcher-Reeves (FR) conjugate gradient method has been established under both exact and strong Wolfe line searches. However, it is performance in practice is poor. In this paper, to get good numerical performance from the FR method, a little modification is done. The global convergence of the modified version has been established for general nonlinear functions. Preliminary numerical results show that the modified method is very efficient in terms of number of iterations and CPU time