318 research outputs found
Java-Based NS2 Network Analyzer
The performance of the network may not be as good as the one estimated before the installation. Hence, installing the computer networks in the different peripherals is
cost effective when we need to change of the peripherals. Therefore, it is always better to have a simulation of the network rather than the actual establishment. As such, there
are many simulators. NS-2 is one of the most popular open source network simulators that widely used in research community, which generates trace file during the simulation experiment. The trace file contains all network events that can be used to calculate network performance. After simulation, the researchers spend much time for analyzing the trace file using traditional scrip tools such as awk or pel to accumulate the result. This project presents Java-Based NS-2 network analyzer (JDNA) as a tool for extracting, analyzing and plotting trace files for the network simulation environment of NS-2. This analyzer enables researcher to analyze and visualize NS-2 trace file quickly and efficiently. It has the ability to visualize more than one trace file simultaneously as well as support all NS-2 trace format. In addition, this project can be a useful guideline to other network researchers or programmers to analyze their networks and to understand how to calculate network performance metrics
A Comparative Study of Transient Stability Power System Analysis Using Energy Function Methods for High Performance of Critical Clearing Time
تتركز دراسة الاستقرارية العابرة في منظومات القدرة الكهربائية على حالات الاضطراب المفاجئ التي تتعرض لها المنظومة على سبيل المثال حالات العطل التي تحدث في المنظومة.تم اعتماد الطرق غير المباشرة والطرق المباشرة لحساب زمن الإزالة الحرج للمنظومات في الطرق غير المباشر ) الخطوة – خطوة ( تتضمن تكرار تكامل المعادلات التفاضلية للمنظومة على طول الزمن اللازم لحالة المنظومة خلال العطل وبعده , ويعاد هذا الحل لكل زمن إزالة عطل. ان هذه الطريقة وبالرغم من دقة نتائجها تستغر ق زمن حسابي كبيروهذا لا يتناسب مع تطور المنظومة الكهربائية لذا فأن الدراسات المستمرة وجدت طرق سريعة وكفوءه لحساب الإزالة الحرج دون اللجوء الى الاعتماد على منحنيات المتغيرات المختلفة للمنظومة لتحديد زمن الازالة الحرج وهي الطرق المباشرة التي تتجاوز الصعوبات المذكورة اعلاه وان هذه الطرق تعتمد على معيار التوازن في الطاقة.
يستعرض البحث دراسة مقارنة بين مختلف طرق دالة الطاقة المتمثلة :طريقة معيار تساوي المساحات الممتدة ,طريقة حد الطاقة الكامنة السطحية ,طريقة نقطة عدم التوازن النسبية والطرق الغير مباشرة في تحليل الاستقرارية العابرة .تم اختبار الطرق على منظومة اربعة مكائن –ستة عقد –وسبعة خطوط .لدالة الطاقة العابرة لمنظومة القدرة مركبتين دالة الطاقة العابرة والطاقة الحرجة تحتسب من اجل الحكم على استقرارية المنظومة.تم الاستنتاج في هذه الدراسة ان طرق دالة الطاقة لاتجنبنا الوقت المستقطع للحل المطلوب لكن تزودنا بدرجة القياس الكمي لاستقرارية المنظومة واقترحت طريقة PEBS. لكونها تحقق الدقة المطلوبة مقارنة بالطرقتيتين EEAC , RUEP)) والطرق التقليدية الاخرى .The power system transient stability studies depend on the state of sudden disturbance to which the system is subjected, such as the fault state on the system. The increasing size of modern power systems requires fast and more efficient methods of solutions. Therefore the classical approach of repeated integrations will be length and time consuming. Investigations to overcome this difficulty led to the use of direct methods. These methods use the energy balance in the system.
This review paper presents the comparative study between the various energy function methods: Extended Equal Area Criterion (EEAC) method, Potential Energy Boundary Surface (PEBS), Relative Unstable Equilibrium Point RUEP, method with the Indirect Integration method of transient stability analysis .the methods was tested on test system 4-machine-six node and seven lines. For transient energy function transient energy and critical energy of the system are calculated in order to judge the stability of the system . In this study it was concluded that the Energy function methods not only avoid the time consuming solutions required in the conventional method, but also provide a quantitative measure of the degree of system stability and the PEBS method is suggested, It achieves more accurate values than other two methods (EEAC, RUEP)and confirms the traditional metho
A Prospective Study of Eighty Cases of Infantile Hypertrophic Pyloric Stenosis
This is a prospective study of (80) cases of infantile hypertrophic pyloric stenosis (I.H.P.S.) who were admitted to the children welfare Teaching Hospital in the period from January 2010 to October 2011. The aim of this study is to analyze the patients according to their age at presentation, sex, family history, body weight at operation, feeding history and general condition of the baby with the result of surgical intervention. Keywords: IHPS, gastric outlet in infants, CHPS, congenital hypertrophic pyloric stenosis
Controlling the Balance of Exploration and Exploitation in ACO Algorithm
خوارزمية النمل هي واحده من خوارزميات البحث عن الحلول المثلى ضمن فضاء واسع من الاحتمالات على نحو شبيه بطريقة النمل في البحث والتقفي لإيجاد الحلول لبعض المشاكل المعقدة التي يصعب حلها باستخدام خوارزميات الذكاء الاصطناعي التقليدية. تستخدم هذه الخوارزمية عمليه البحث في فضاء الحالات للاستنتاج حلول مختلفة اثناء عمليه البحث معتمدة على التوازن بين استكشاف حلول جديدة لتوسيع رقعة البحث وبين استغلال الحلول الجيدة لتحسين الحلول المستخرجة مسبقا. ان عمليه خلق توازن بين هاتين العمليتان يؤدي لتحسين النتائج والخروج بحلول أكثر امثليه. هدف هذا البحث هو ايجاد قانون احتمالي أكثر ملاءمة وقادر على خلق توازن أفضل بين عمليتي الاستكشاف والاستغلال. بعد اجراء ستة تجارب مختلفة من حيث أشكال البينات تم اثبات ان التحسين في هذه الخوارزمية يؤدي الى انتاج حلول عالية الجودة من ناحية قصر طول المسار المكتشفAnt colony optimization is a meta-heuristic algorithm inspired by the foraging behavior of real ant colony. The algorithm is a population-based solution employed in different optimization problems such as classification, image processing, clustering, and so on. This paper sheds the light on the side of improving the results of traveling salesman problem produced by the algorithm. The key success that produces the valuable results is due to the two important components of exploration and exploitation. Balancing both components is the foundation of controlling search within the ACO. This paper proposes to modify the main probabilistic method to overcome the drawbacks of the exploration problem and produces global optimal results in high dimensional space. Experiments on six variant of ant colony optimization indicate that the proposed work produces high-quality results in terms of shortest route
Managing diversity: Academics' perspective on culture and teaching
As UK Higher Education institutions continue to accept students from ethnically diverse backgrounds, there is now an onus and an expectation for academics to provide learning environments and experiences that are inclusive, validating and affirming. The aim of this paper is to explore, through the lens of the academic tutor, the pedagogical methods employed towards the implementation of ‘cultural branching’, which we define as helping ethnically diverse students to build bridges between their pre-existing knowledge and what they are expected to learn. To investigate this in more detail, the researchers interviewed 22 academic tutors across three UK Higher Education Institutions in the North of England. The findings suggest that current curriculum structures and pedagogical approaches favour the dominant non-ethnically diverse learner. Our research proposes that additional emphasis needs to be placed on developing a practical and functional approach which embeds cultural branching via technological platforms
Studies of Thermal Stability of Polymers by Thermal Volatilisation Analysis
A great deal of work has been carried out on the degradation of polystyrene in order to elucidate the mechanism of the reactions involved. Most of the workers have assumed that transfer reactions are taking place and included them as a factor in the theoretical treatments of the kinetics of degradation. Other workers have shown, by indirect experimental work, that transfer reactions to take part in the degradation process of this polymer. However, this work is a direct attempt to show that intermolecular transfer is a major factor taking part in the degradation process. The technique used was the TVA where the small pressure which exists in a continously evacuated system between a hot sample, decomposing to volatile products, and a cold trap placed some distance away is recorded continuously as the temperature of the sample is increased in a linear manner. The TVA curve indicates the variation of rate of volatilization of the sample with temperature. The degradation method used was that of comparing the thermal stability of very thin films of polymer with that of the thicker films. Degradation was carried out under conditions of temperature rise of 10 C/min. or at isothermal temperatures. Thin films of polystyrene were observed to be thermally more stable than the bulk material. The molecular weight dropped more sharply in the case of thick films when compared with thin films of the same sample weight. More styrene monomer was produced from degraded thin films than from the thicker films. Also, the shape of the curve of the rate of volatilization against percentage conversion in thin films resembled that of poly (a- methyl styrene) where the zip length is much greater than the chain length. This behaviour was considered to be due to the reduction of intermolecular transfer reactions in thin films of polystyrene. Polymers where transfer reactions are well established such as polypropylene, poly (isobutene) and some elastomers were also examined and showed an effect of thin film stability similar to that observed in polystyrene. Poly (methyl methacrylate) was also examined in the form of thin and thick films and in powder form. The results suggested that transfer reactions of the secondary hydrogen atoms might be taking place to some extent. Poly (methyl acrylate) which contains a tertiary hydrogen atom showed an effect similar to that observed in polystyrene; while there was no change in thermal stability of thin and thick films of poly (tert. butyl methacrylate). Very few useful conclusions could be drawn from results obtained from the degradation of thin and thick films of PVC, PVA and poly (vinyl alcohol)
Identification of Cultural Heuristics for the creation of consistent and fair pedagogy for ethnically diverse students.
This book chapter intends to illustrate the complexity of supporting culturally diverse students in UK Higher Education Business Schools and how this complexity is compounded by pedagogy, which is shaped by educational practice that is dominated by aspirations of Western culture. The role that culturally responsive teaching can play as an approach to meeting the educational needs of students whose educational framework and culture are different from western mainstream education is also explored within the context of UK Business Schools. This chapter investigates the cultural constructs of culturally responsive teaching within the structured framework of the five-pillars of Jabbar and Hardaker (2013). We propose, through the identification of the cultural constructs, that within HE there are gaps within fundamental areas that should be developed to consistently engage with students in a fair, consistent and equitable manner
The efficient interleaving of digital-video-broadcasting-satellite 2nd generations system
The DVB-S2 system is designed as a toolbox to permit the execution of the satellite programs. Interleaver is an essential part of the DVB-S2 system. The current general block interleaver in DVB-S2 is not best, which leads to high BER and maybe not satisfy the requirements of the system. The purpose of this paper is to study the several interleaver types and comparative analyses are done between them to find which of these give better performance. Simulations results obtained prove that the 2D interleavers minimize BER more than other interleavers of DVB-S2. Further, the performance of 2D interleaver is better on a system that required a low SNR
Design and implement a smart system to detect intruders and firing using IOT
The security system is essential for occupants' convenience and protection from intruders and fire. Theft and fire are the most important requirement for the security system. The advancement of wireless sensor networks using IOTs increased the features in a security system and play an important role in daily life. In this paper, the proposed system is divided into two units. The first one about security which use to take snapshots by a camera whenever there is fire or intruders in the security zone and mail it to the owner every three seconds by using Arduino configured with MATLAB program. MATLAB program plays the main role to coordinate between sensors and to turn on/off the cameras. The second unit is about controlling the appliances and also the main door by using AVR microcontroller configured by CVAVR software that connected with Bluetooth sensor and controlled by a smartphone by using the implementation software built-up in the smartphone. To arrival of the control unit, the user should send code from the software implementation to the framework that use to turn on /off the devices or open/close the door. This proposed system is designed and implemented in details in this paper
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