RHLB: Improved Routing Load Balancing Algorithm Based on Hybrid Policy

يتم تعريف الشبكة على أنها مجموعة من العقد المرتبطة بطريقة للتعامل مع البيانات والرسائل ونقلها من المصدر إلى الوجهة. يحدث الازدحام في الشبكة عند حدوث الكثير من الزيارات، ويؤدي إلى التأخير، وفقدان الحزمة، وتدهور عرض النطاق الترددي، وارتفاع حمل الشبكة. تم تصميم خوارزميات موازنة التحميل لتقليل الازدحام في الشبكة. موازنة التحميل هي إعادة توزيع عبء العمل بين عقدتين أو أكثر ليتم تنفيذها في نفس الوقت. اثنين من السياسات من خوارزميات موازنة التحميل: موازنة تحميل ثابتة وديناميكية. تقترح هذه الورقة خوارزمية موازنة التحميل على أساس الهجين (سياسة ثابتة وديناميكية) باستخدام شبكة المحاكاة (الاصدار الثاني). يتم استخدام السياسة المختلطة لتحسين أداء الشبكة من خلال إعادة توزيع الحمل بين العقد الزائدة إلى العقد الأخرى التي يتم تحميلها عند حدوث الازدحام. وتبين نتائج المحاكاة أن الخوارزمية المقترحة تستخدم أداء الشبكة فيما يتعلق بالانتقال، ونسبة توصيل الرزم، وفقدان الرزم، والتأخر من طرف إلى آخر.A network is defined as a set of nodes that are associated with a way to handle and transfer data and messages from source to destination. The congestion in the network occurs when a lot of traffic occurs, leads to delay, packet loss, bandwidth degradation, and high network overhead. Load balancing algorithms have been designed to reduce congestion in the network. Load Balancing is the redistribution of workload between two or more nodes to be executed at the same time. Two policies of load balancing algorithms: static and dynamic load balancing. This paper proposes a load balancing algorithm based on the hybrid (static and dynamic) policy using Network Simulator (version 2). The hybrid policy is used to improve network performance by redistributing the load between overloaded nodes to other nodes that are under loaded when congestion occurs. The simulation results show that the proposed algorithm used performance of the network with regard to throughput, packet delivery ratio, packet loss and the end-to-end delay

Synthesis, characterization and preliminary pharmacological evaluation of new non-steroidal anti-inflammatory pyrazoline derivatives

A series of six pyrazoline ring derivatives as a pharmacophore were incorporated to the naproxen; to increase its size were synthesized and preliminarly evaluated as anti-inflammatory agents with expected selectivity toward COX-2 enzyme. In vivo acute anti-inflammatory effects of the final compounds (5a-f) were evaluated in rats using egg-white induced edema model of inflammation. The tested compounds and the reference drug (naproxen) produced significant reduction of paw edema with respect to the effect of control group (propylene glycol 50%, v:v). However, compound 5d and 5e show comparable effect to naproxen at all experimental time while compounds 5a, 5b and 5c produced significantly lower inhibitory effect than naproxen at time 120-240 minutes. Furthermore, compound 5f exert significantly higher paw edema reduction than naproxen at 60-240 min. Also the antibacterial activities of the final compounds were evaluated by Well Diffusion Method. All tested compounds exert significant antibacterial activity against tested Gram positive and Gram negative bacteria in comparison to dimethyl sulfoxide as control group. In comparison the antibacterial results among the tested compound 5e may regard the best one and compound 5c the lower one

QUANTITATIVE ASSAY OF ASPIRIN AND (SALICYLIC ACID AND HEAVY METALS AS IMPURATIES) IN IRAQI’S MARKET ASPIRIN TABLETS USING DIFFERENT ANALYTICAL METHODS

Objective: Easy and precise methods were developed for estimation of aspirin (ASP), impurities from such as salicylic acid (SAL) and heavy metal ions (HMI) in ASP tablets that available in the Iraqi’s market using High-performance liquid chromatography (HPLC), UV–VIS spectrophotometry and atomic absorption spectrophotometric (AAS). Methods: HPLC separation was carried out using C18 as stationary phase and acetonitrile (ACN): water in the ratio of (10: 90 v/v) as a mobile phase for HPLC method and as a solvent for UV-VIS spectrophotometric for quantitative ASP and SAL at 254 nm for HPLC, 226 and 296 nm for UV measurements. AAS was used for HMI determination. Results: ASP and SAL gave absorbance maxima at 226 and 296 nm in ACN: H2O solvent. The Beer’s law was obeyed in the range of 0.05-20 for ASP and 0.02-8 µg/ml for SAL. Correlation coefficients (R2) were 0.9996 and 0.9992 for ASP and SAL respectively, for HPLC and LOD value was 0.006 for ASP and 0.004 μg/ml for SAL. The % recovery for the developed method was found to be in the range of (98.80 to 101.26%) and (98.67 to 103.33%) for ASP and SAL respectively, within the acceptable range, that approved by world health organization (WHO). Conclusion: The proposed method can help research studies, quality control and routine analysis with lesser resources available. The results of the assay of pharmaceutical formulation of the developed method are highly reliable and reproducible and is in good agreement with the label claim of the medicines

Fiber optical parametric amplifier with dispersion flattened photonics crystal fiber as a gain medium

A fiber optical parametric amplifier utilizing single continuous wave pump is demonstrated. Gain medium used for parametric amplification is a 50 m long dispersion flattened photonics crystal fiber. The relatively wide bandwidth of pump is able to suppress stimulated Brillouin scattering, allowing the parametric amplifier to operate without modulating the pump. Internal fiber gain as high as 17.1 dB can be achieved with this configuration

Generation of optical frequency combs with a short photonics crystal fiber

Self-seeded four wave mixing (FWM) cascades with a 50 m long photonics crystal fiber (PCF) as the parametric gain medium are presented. Up to six comb lines are successfully generated when the amplifier output power is set at 519.28 mW. That relatively short length of the PCF enables the proposed scheme to be more compact in size in comparison to a 500 m long of highly nonlinear fiber, utilized in previous work

Multi-wavelength generation by self-seeded four-wave mixing

A cost effective method of generating multi-wavelength based on the cascaded four wave mixing effect is experimentally demonstrated. The proposed scheme is free from external tunable laser sources and pump modulators, resulting from the use of a broadened linewidth tunable dual wavelength erbium-doped fiber laser as intracavity pump. In this configuration, the number of four wave mixing cascades becomes larger in tandem with the increment of erbium-doped fiber amplifier output power. When its output power is set at 20.57 dBm, six waves having optical signal to noise ratio larger than 10 dB are generated. The six waves are stable with peak power fluctuations less than 1 dB within 30 minutes period and tunable with wavelength spacing ranging from 1.03 nm to 11.31 nm

Impact of four wave mixing on OSNR of multiwavelength Brillouin-erbium fiber laser

An experimental investigation on the optical signal to noise ratio (OSNR) of a multiwavelength Brillouin erbium fiber laser (BEFL) without and with four wave mixing (FWM) effect is demonstrated. The BEFL output before and after an 11 km dispersion compensating fiber is compared in terms of OSNR. It is found that FWM does affect the OSNR of the channels. For the first few channels, the OSNR is lower as compared with the case without FWM effect but for the last few channels, the OSNR is higher

Broadly tunable multiwavelength fiber laser with bismuth-oxide EDF using large effective area fiber

A multiwavelength laser comb using 2.49 m Bismuth-oxide erbium-doped fiber (Bi-EDF) with different lengths of large effective area fiber (LEAF) in a ring cavity configuration is realized. The Bi-EDF is used as the linear gain medium and LEAF is used as the non-linear gain medium for stimulated Brillouin scattering. Out of the four different lengths, the longest length of 25 km LEAF exhibits the widest tuning range of 44 nm (1576 to 1620 nm) in the L-band at 264 mW pump power and 5 mW Brillouin pump power. In addition, a total of 15 output channels are achieved with total average output power of -8 dBm from this laser structure. All Brillouin Stokes signals exhibit high peak power of above -20 dBm per signal and their optical signal-to-noise ratio of greater than 15 dB

Gold-nanoparticles microfiber saturable absorber for mode-locked erbium-doped fiber laser

We demonstrate the generation of 743 fs soliton pulses in erbium-doped fiber laser employing gold-nanoparticles saturable absorber. The mode-locking operation is achieved with gold-nanoparticles/polydimethyl-siloxane composite coated on a microfiber with 10\\mu m}. waist diameter, indicating the availability of fabricated saturable absorber for pulsed operation in 1.55\\mu m} spectral range

Effect of gold-nanoparticle size on microfiber saturable absorber for mode-locked erbium-doped fiber lasers

Effect of gold-nanoparticle size on microfiber saturable absorber for mode-locked erbium-doped fiber lasers The optical performance of passively mode-locked erbium-doped fiber laser incorporating gold-nanoparticles (Au-NPs) of different sizes as saturable absorbers (SAs) was compared. A composite of Au-NPs with polydimethylsiloxane was spin coated on the surface of a microfiber waveguide. The fabricated Au-NP-based SA was deployed in a ring cavity erbium-doped fiber laser and its lasing performance was evaluated by comparing SA characteristics as well as pulse qualities among the different Au-NP sizes. The optimum pulse performance was realized when the SA was fabricated with 20 and 40 nm Au-NP size. For the former, time-bandwidth product of 0.34 was demonstrated which was the closest to its bandwidth-limited pulse. As for the latter, the fabricated SA exhibited 4.0% modulation depth and an average pulse duration of 886.7 fs. The research work has demonstrated the functionality of Au-NPs as a saturable absorption material for ultrashort pulses generation. In addition, the influence of nanomaterial size towards the characteristics of saturable absorbers, ergo the quality of laser pulse, was verified. This finding is also valuable in customizing ultrashort pulse output that can effectively suit system performance need