A quantitative analysis and performance study of fast congestion notification (FN) mechanism

Congestion in computer network happens when the number of transmission requests exceeds the transmission capacity at a certain network point (called a bottle-neck resource) at a specific time. Congestion usually causes buffers overflow and packets loss. The purpose of congestion management is to maintain a balance between the transmission requests and the transmission capacity so that the bottle-neck resources operate on an optimal level, and the sources are offered service in a way that assures fairness. Fast Congestion Notification (FN) is one of the proactive queue management mechanisms that limits the queuing delay and achieves the maximum link utilization possible with minimum packet drops. In this paper we present a detailed performance comparison of the Linear FN algorithm to RED based on the results obtained through simulations. The paper shows how FN can be tuned for different window size (Ws) and periods of time constant (T) to achieve higher link utilization; reduce the queuing delay, and lower packet drop ratio

The Uniformization Process of the Fast Congestion Notification (FN)

Fast Congestion Notification (FN) is one of the proactive queue management mechanisms that practices congestion avoidance to help avoid the beginning of congestion by marking or dropping packets before the routers queue gets full; and exercises congestion control, when congestion avoidance fails, by increasing the rate of packet marking or dropping. Technically, FN avoids the queue overflows by controlling the instantaneous queue size below the optimal queue size, and control congestion by keeping the average arrival rate close to the outgoing link capacity. Upon arrival of each packet, FN uses the instantaneous queue size and the average arrival rate to calculate the packet marking or dropping probability. FN marks or drops packets at fairly regular intervals to avoid long intermarking intervals and clustered packet marks or drops. Too many marked or dropped packets close together can cause global synchronization, and also too long packet intermarking times between marked or dropped packets can cause large queue sizes and congestion. This paper shows how FN controls the queue size, avoids congestion, and reduces global synchronization by uniformizing marked or dropped packet intervals.Comment: 5 Pages IEEE format, International Journal of Computer Science and Information Security, IJCSIS 2009, ISSN 1947 5500,Impact Factor 0.423, http://sites.google.com/site/ijcsis

Batch and flow injection spectrophotometric methods for determination of Ceftazidime in pharmaceutical formulations

  تم وصف تقنيتين طيفيتين لقياس كمية السيفتازيديم (CFT) في الأدوية والتركيبات الصيدلانية.  فهي بسيطة وحساسة وانتقائية ودقيقة وفعالة.  يستخدم الأسلوب الأول وسيطًا قلويًا لتحويل السيفتازيديم إلى ملح الديازونيوم ، والذي يتم دمجه بعد ذلك مع كواشف1-Naphthol (1-NPT) و2)2-Naphthol-NPT).  تم إنتاج صبغة الآزو باللونين البني والأحمر ، مع كثافة امتصاص تصل إلى ƛmax 585nm and max 545nm ، على التوالي.  تم اتباع قانون بير من حيث مدى التركيز (3-40) لـ (CFT-1-NPT) و (CFT-2 NPT) ، كانت حدود الكشف 1.0096 and 0.8017 g.ml-1على التوالي ، وكانت الامتصاصية المولية  0.7926×104 and 0.5466×104 L.mol1cm-1. 0تُستخدم طريقة تحليل حقن التدفق (FIA) لتقدير السيفتازيديم وتسجيل القياسات باستخدام نهج الأشعة فوق البنفسجية المرئية في الإجراء الثاني.  يسمح حقن التدفق بتقدير دقيق للعقار في ظل ظروف تجريبية مثالية.  كانت التركيزات في نطاق(3-50)  لـ (CFT-1-NPT) و (CFT-2-NPT) ، وكانت حدود الكشف0.8102, 1.2809g.ml-1 . ، والامتصاصية المولية 0.9565×104  ,0.7106×104 L.mol-1. cm-1, على التوالي تم استخدام الأسلوبين المقترحين لتقدير السيفتازيديم في المستحضرات الصيدلانية بنجاح حيث تميزت هذه الطريقة بالبساطة والسرعة والدقة والتكلفة المنخفضة.It is generally accepted that there are two spectrophotometric techniques for quantifying ceftazidime (CFT) in bulk medications and pharmaceutical formulations.  The methods  are described as simple, sensitive, selective, accurate and efficient techniques. The first method used an alkaline medium to convert ceftazidime to its diazonium salt, which is then combined with the 1-Naphthol (1-NPT) and 2-Naphthol (2-NPT) reagents. The azo dye that was produced brown  and red in color with absorption intensities of ƛmax 585 and 545nm respectively. Beer's law was followed in terms of concentration ranging from  (3-40) µg .ml-1 For (CFT-1-NPT) and (CFT-2-NPT), the detection limits were 1.0096 and 0.8017 µg.ml-1, respectively, and the molar absorptivity was 0.7926×104 and 0.5466×104 L.mol-1.cm-1. The Flow Injection Analysis (FIA) method is used to estimate ceftazidime and in the second procedure record measurements using the UV-Visible approach. The Flow injection allows for exact drug estimation under ideal experimental conditions. The concentrations were in the range of (3-50) µg .ml-1 For (CFT-1-NPT) and (CFT-2-NPT), the detection limits were 0.8102, 1. 2809µg.ml-1, and the molar absorptivity was 0.9565×104 ,0.7106×104 L.mol-1.cm-1, respectively. The proposed two methods for determination Ceftazidime in Pharmaceutical formulation were successfully applied, as these methods were characterized by simplicity, speed, accuracy, and low cost

The effect of Tramadol on some blood and biochemical parameters of male rats (Rattus norvegicus)

The present study aimed to explain the dose-dependent possible deleterious effects of 30 day administration of Tramadol on some hematological and biochemical parameters of laboratory male rats (Rattus norvegicus), the study consisted of eighteen adult male rats randomly divided into three equal groups (each of six). Group 1 (control) were treated by intraperitoneal injection of normal saline solution (0.2 ml), group two (low dose) was treated by intraperitonealy (i.p) injection of Tramadol at a dose of 50 mg/kg/day, group three (high dose) was treated by intraperitonealy injection of Tramadol at a dose of 100 mg/kg/day for 30 days. At the end of experimental period, rats were sacrificed. Blood were collected by cardiac puncture to investigate blood film and biochemical parameters which include Aspartate transaminase (AST), Alanine transaminase (ALT), urea, and glucose. Results explained a significant reduction in hemoglobin (Hb), packed cell volume (PCV), and red blood cells count (RBC), in both treated group and significant elevation in WBC count which is clearly appeared in lymphocyte count, while the biochemical results showed a significant increased in ALT, blood urea, and decreased in blood glucose level in high dose treated group mostl

Complex of Lascoux in Partition (6,6,3)

In this paper, the complex of Lascoux in the case of partition (6,6,3) has been studied by using diagrams, divided power of the place polarization nbsp,Capelli identities and the idea of mapping cone

Application of the resolution of the characteristic-free resolution of Weyl module to Lascoux resolution in case (6,6,3)

In this paper we study the relation between the resolution of Weyl module nbspin characteristic-free mode and in the Lascoux mode (characteristic zero), more precisely we obtain the Lascoux resolution of nbspin characteristic zero as an application of the resolution of nbspin characteristic-free

New Spectrophotometric Estimation and Cloud Point Extraction of Cefdinir

A sensitive spectrophotometric method was developed for the estimation of cefdinir (CFD), a cephalosporin species. This study involves two methods, and the first method includes the preparing of azo dye by the reaction of CFD diazonium salt with 4-Tert-Butylphenol (4-TBP) and 2-Naphthol (2-NPT) in alkaline medium, which shows colored dyes measured at λmax 490 and 535 nm, respectively. Beer's law was obeyed along the concentration range of (3-100) μg.ml-1. The limits of detection were 0.246, 0.447 μg.ml-1 and molar absorptivities were 0.6129×104, 0.3361×104 L.mol-1cm-1 for (CFD-4-TBP) and (CFD-2-NPT), respectively. The second method includes preconcentration for cefdinir dyes by using cloud point extraction in the presence of Triton X-114 (10% v/v) and recording measurements using the UV-Visible technique. Cloud point extraction enables the drug to be precisely estimated under the optimal experimental conditions. The concentrations were ranged between (0.1-6.0) and (0.2-6.0) μg.ml-1. The limits of detection were 0.032, 0.054 μg.ml-1 and molar absorptivities were 0.4733×105, 0.2788×105 L.mol-1cm-1, respectively. Enrichment factors were 24.61, 24.58, and distribution coefficients were 1526, 1393 for (CFD-4-TBP), (CFD-2-NPT), respectively. The proposed methods have been applied for the determination of CFD in commercial formulation with no interference. The results appear to be no significant difference between the two methods

Position control of electro-hydraulic actuator system using fuzzy logic controller optimized by particle swarm optimization

The position control system of an electro-hydraulic actuator system (EHAS) is investigated in this paper. The EHAS is developed by taking into consideration the nonlinearities of the system: the friction and the internal leakage. A variable load that simulates a realistic load in robotic excavator is taken as the trajectory reference. A method of control strategy that is implemented by employing a fuzzy logic controller (FLC) whose parameters are optimized using particle swarm optimization (PSO) is proposed. The scaling factors of the fuzzy inference system are tuned to obtain the optimal values which yield the best system performance. The simulation results show that the FLC is able to track the trajectory reference accurately for a range of values of orifice opening. Beyond that range, the orifice opening may introduce chattering, which the FLC alone is not sufficient to overcome. The PSO optimized FLC can reduce the chattering significantly. This result justifies the implementation of the proposed method in position control of EHAS