Agile-SD: A Linux-based TCP Congestion Control Algorithm for Supporting High-speed and Short-distance Networks

Recently, high-speed and short-distance networks are widely deployed and their necessity is rapidly increasing everyday. This type of networks is used in several network applications; such as Local Area Networks (LAN) and Data Center Networks (DCN). In LANs and DCNs, high-speed and short-distance networks are commonly deployed to connect between computing and storage elements in order to provide rapid services. Indeed, the overall performance of such networks is significantly influenced by the Congestion Control Algorithm (CCA) which suffers from the problem of bandwidth under-utilization, especially if the applied buffer regime is very small. In this paper, a novel loss-based CCA tailored for high-speed and Short-Distance (SD) networks, namely Agile-SD, has been proposed. The main contribution of the proposed CCA is to implement the mechanism of agility factor. Further, intensive simulation experiments have been carried out to evaluate the performance of Agile-SD compared to Compound and Cubic which are the default CCAs of the most commonly used operating systems. The results of the simulation experiments show that the proposed CCA outperforms the compared CCAs in terms of average throughput, loss ratio and fairness, especially when a small buffer is applied. Moreover, Agile-SD shows lower sensitivity to the buffer size change and packet error rate variation which increases its efficiency.Comment: 12 Page

Experimental research into the effect of some operation factors and rock properties on the rate of penetration

Purpose. The purpose of this research is to investigate the effect of weight on bit (WOB), rotary speed (RPM), and some rock properties on the rate of penetration (ROP). Methods. Four types of rock were collected from different sites in the south of Egypt (Aswan sandstone, Isawya limestone, Assiut limestone, and Minya marble). These tested samples were drilled by diamond core bit using a fixed laboratory diamond drilling machine under conditions (400 and 1200 rpm), and loads from 12 to 220 kg. WOB, ROP, torque (T) and specific energy (SE) were continuously observed during the drilling trials. The effect of these factors on ROP were examined. Water is used as a flushing and cooling medium. Findings. The effect of some operation factors on the penetration rate regarding mineral composition and different rock type was evaluated and the general equation was carried out to predict the suitable operation factor which gives the best penetration Rate. Originality. The effect of some operation factors on the penetration rate regarding mineral composition and different rock type was evaluated and the general equation was carried out to predict the suitable operation factor which gives the best penetration Rate. Practical implications. The Results demonstrated that ROP was inversely proportional to compressive strength (CS), tensile strength (TS), and density. It was also found that Aswan sandstone, Isawya limestone, Assiut limestone, and Minya marble have CS 111.94 MPa, 131.22 MPa, 125.0 MPa, and 502.5 MPa respectively. Was established that ROP was directly proportional to porosity. Increasing ROP in case of Aswan sandstone is associated with increase in porosity – 23.158%, and in case of Assiut limestone and Isawya limestone ROP is also associated with an increase in porosity – 19.9% and 17.93% respectively. Decreasing ROP in case of Minya marble is associated with decrease in porosity – 2.314%. So, we concluded that marble has lower ROP due to its higher CS, TS, and density and lower porosity than other tested rocks.Мета. Вивчення впливу комплексу основних експлуатаційних параметрів і ряду фізико-механічних властивостей порід на швидкість буріння в умовах різних родовищ Південного Єгипту. Методика. Були відібрані 4 типи порід з різних районів на півдні Єгипту (Асуанської піщаник, вапняк Ісав, Ассіутскій вапняк і мармур Міньї). Експериментальні зразки отримано на стаціонарній лабораторній буровій установці з алмазним долотом при швидкостях обертання 400 і 1200 об/хв та при навантаженнях від 12 до 220 кг. Під час експериментів постійно вимірювалися навантаження на долото, частота обертання, крутний момент на долоті й питома енергія, а також досліджувався вплив цих факторів на швидкість буріння. Як розчин для промивання і охолоджуючий агент використовувалася вода. Результати. Встановлено залежності швидкості буріння від навантаження на долото, питомої енергії та частоти обертання і питомої енергії. Виявлено, що для всіх чотирьох типів породи швидкість буріння збільшується з ростом навантаження на долото, в той час як питома енергія зменшується з ростом швидкості буріння. Розроблено ефективний спосіб прогнозування продуктивності бурової установки. Встановлено, що швидкість буріння обернено пропорційна міцності на стиск, міцності на розтягнення й щільності, а також змінюється прямо пропорційно пористості. Визначено, що менша швидкість буріння мармуру пов’язана з великими значеннями міцності на стиск, розтяг і щільність, а також з меншою пористістю у порівнянні з іншими досліджуваними породами. Наукова новизна. Встановлено нові закономірності взаємозв’язку експлуатаційних параметрів буріння з урахуванням різного типу породи (пісковик, вапняк, мармур) та її мінерального складу, а також обґрунтовано головну умову експлуатаційного фактору, який забезпечує оптимальну швидкість буріння. Практична значимість. Отримані результати дозволяють вибирати оптимальні параметри і режими буріння в процесі розвідки умов залягання родовищ Південного Єгипту, їх мінерального вмісту та стратиграфічних особливостей. Результати будуть корисними для проектних організацій, наукових інститутів з геології й розвідки, а також гірничих підприємств.Цель. Изучение влияния комплекса основных эксплуатационных параметров и ряда физико-механических свойств пород на скорость бурения в условиях пород различных месторождений Южного Египта. Методика. Были отобраны 4 типа пород из различных районов на юге Египта (Асуанский песчаник, известняк Исавии, Ассиутский известняк и мрамор Миньи). Экспериментальные образцы получены на стационарной лабораторной буровой установке с алмазным долотом при скоростях вращения 400 и 1200 об/мин и при нагрузках от 12 до 220 кг. Во время экспериментов постоянно измерялись нагрузки на долото, частота вращения, крутящий момент на долоте и удельная энергия, а также и исследовалось влияние этих факторов на скорость бурения. В качестве промывочного раствора и охлаждающего агента использовалась вода. Результаты. Установлены зависимости скорости бурения от нагрузки на долото, удельной энергии и частоты вращения и удельной энергии. Выявлено, что для всех четырех типов породы скорость бурения увеличивается с ростом нагрузки на долото, в то время как удельная энергия уменьшается с ростом скорости бурения. Разработан эффективный способ прогнозирования производительности буровой установки. Установлено, что скорость бурения обратно пропорциональна прочности на сжатие, прочности на растяжение и плотности, а также изменяется прямо пропорционально пористости. Определено, что меньшая скорости бурения мрамора связана с большими значениями прочности на сжатие, растяжение и плотности, а также с меньшей пористостью по сравнению с другими исследуемыми породами. Научная новизна. Получены новые закономерности взаимосвязи эксплуатационных параметров бурения с учетом различного типа породы (песчаник, известняк, мрамор) и ее минерального состава, а также обосновано главное условие эксплуатационного фактора, который обеспечивает оптимальную скорость бурения. Практическая значимость. Полученные результаты позволяют выбирать оптимальные параметры и режимы бурения в процессе разведки условий залегания месторождений Южного Египта, их минерального содержание и стратиграфических особенностей. Результаты будут полезными для проектных организаций, научных институтов по геологии и разведке, а также горных предприятий.Our sincere gratitude for Mining and Metallurgical Engineering Dept. Faculty of Engineering, Assiut, Egypt for invaluable assistance to upgrade and guidance to completed this article

Studying the Dynamical Properties of 20 Nearby Galaxy Clusters

Using SDSS-DR7, we construct a sample of 42382 galaxies with redshifts in the region of 20 galaxy clusters. Using two successive iterative methods, the adaptive kernel method and the spherical infall model, we obtained 3396 galaxies as members belonging to the studied sample. The 2D projected map for the distribution of the clusters members is introduced using the 2D adaptive kernel method to get the clusters centers. The cumulative surface number density profile for each cluster is fitted well with the generalized King model. The core radii of the clusters' sample are found to vary from 0.18 Mpc \mbox{h}^{-1} (A1459) to 0.47 Mpc \mbox{h}^{-1} (A2670) with mean value of 0.295 Mpc \mbox{h}^{-1}. The infall velocity profile is determined using two different models, Yahil approximation and Praton model. Yahil approximation is matched with the distribution of galaxies only in the outskirts (infall regions) of many clusters of the sample, while it is not matched with the distribution within the inner core of the clusters. Both Yahil approximation and Praton model are matched together in the infall region for about 9 clusters in the sample but they are completely unmatched for the clusters characterized by high central density. For these cluster, Yahil approximation is not matched with the distribution of galaxies, while Praton model can describe well the infall pattern of such clusters.Comment: 16 pages, 8 figure

Conformal mapping of unbounded multiply connected regions onto canonical slit regions

We present a boundary integral equation method for conformal mapping of unbounded multiply connected regions onto five types of canonical slit regions. For each canonical region, three linear boundary integral equations are constructed from a boundary relationship satisfied by an analytic function on an unboundedmultiply connected region. The integral equations are uniquely solvable. The kernels involved in these integral equations are the modified Neumann kernels and the adjoint generalized Neumann kernels

Employee attitudes as a mediator between HRM and organizational performance

Attitude is a power that controls human behaviour. When employee Attitude is positive, it can give impact positive to organization performance. A proper human resource management (HRM) managed by organization, the employee attitude will be affected. HRM practices influence employee attitude positively and there is a mediating role of employee attitude between training and development dimension of HRM practices and organizational performance. Therefore, the purpose of this study is to explore employee atttiude as a mediator between HRM and organizational performance. A sample of this study was 219 respondents from employee construction in Libya. The data was analyzed using structural equation modelling (SEM) approach. This study showed that employee attitudes is a full mediator between relationship HRM and organizational performance. Therefore, HRM practices influence employee attitude and its give impact to organizational performance for more effective and efficient in achieving organization goal

Analysis of the Architectural heritage of El-Mansoura city, Egypt: towards urban conservation approach

Mansoura city is one of the Egyptian intermediate cities in the Nile delta, The city center heritage are in mostly the European Mediterranean style because of the presence of the foreigners in the city spatially Greek and Italian communities during the nineteenth and twentieth centuries. As many other Egyptian intermediate cities, the city heritage suffers from lack of maintenance and the absence of organized conservation programs. El-Mansoura architectural heritage are divided into main five zones around the city center. The first is the “private palaces and villas zone” in the west of the city center, it was the residence of the aristocratic Egyptians. The second is the “Northern city center” on the Nile, it was the administration zone near the old port. The third is the “Commercial center” with high concentration of commercial activities. The fourth is “El-Mokhtalat neighborhood” in the east of the city center, it was the residence of the foreigners and elite Egyptians. The last one is “Torel neighborhood” it is a combination of private villas in a grid of perpendicular street. Their are some trials to preserve and restore some building of the city heritage but normally they are individual trails and some times without professional procedures and studies, Now there is some projects to make urban development of the city valuable zones in collaboration between “El-Dakahlia’ governorate and “Mansoura university, Department of architectural engineering” and that will lead to effective restoration and rehabilitation projects in the future

Effect Of Selected Shading Devices On Office Room Temperature

This study investigated the effects of selected shading devices on office room temperature at Universiti Putra Malaysia. The experimental and simulation results were presented to show the thermal effects of coating systems used. Initial work for a duration of two months showed that high temperatures occurred at 10:00, 1200 and 14:00 hours. This frequency of measurement is similar to that of Etzion and Erell (2000). Thermocouple wires were used to measure the air temperature in an office of size 4.03 m x 3.82 m x 2.60 m (length x width x height). The window was a vertical glass plate with thickness 5 mm, height 1.53 m and width 2.12 m and it was facing northeast. Coating materials used were plain glass pane thickness 5 mm (control), tinted film, silver film, and blinds. Results showed that the differences in temperature between the inside and outside of the office were 4.4oC, 3.8oC, 3.5oC and 2.9oC for silver film, blinds, tinted film and clean glass (5 mm), respectively. Comparison between simulated and experimental results showed a reasonable agreement, ranging between 0.2 to 10 %. The external air velocity ranged between 0.19 and 0.45 ms-1 and relative humidity between 22.7% and 77.5 %, while the average air velocity in the office ranged from 0.03 to 0.05 ms-1 and relative humidity from 57.2 % to 66.8 %. The simulated results for internal air temperatures of the office ranged from 28oC to 29oC. In terms of cost, the blinds gave value for money with every temperature drop for temperature difference between internal and external temperatures. In addition the blinds could be easily fixed

Allelopathic effect of imperata cylindrica (L.) beauv. extracts on the germination of weeds

In this study, the allelopathic effect of Imperata cylindrica has been investigated. Aqueous extracts of Imperata cylindrica were tested at concentrations of 31.25, 62.5, and 125 mg/ml to study different parameters on Cucumis sativus and Lolium perenne Similarly, allelopathic effect of Imperata cylindrica root and shoot 70 % ethanol extract fractions (obtained by different polarity solvents), that is, A, B, C, and D, were also tested at 0.125, 0.25, and 0.5 mg/ml concentrations on four different plants; Linum usitatissimum, Lolium perenne, Macroptilim lathyroides, and Phalaris canariensis. Distilled water and glyphosate were used as negative and positive control, respectively. Various factors were studied to determine the inhibition and growth of root and shoot length, percentage germination, and fresh and dry weight. Results indicated that the extracts of Imperata cylindrica may contain allelochemicals which may contribute to its invasiveness and extreme competitiveness. While the gas chromatography-mass spectroscopy analysis (GC�MS) of active fractions revealed the presence of allelochemicals including phenolic acid, fatty acids, and organosilicon compounds. Although phenolic acids [butyl phenol, phenyl 3-methylbut-2-enoate, p-coumaric acid, and p-coumaric acid methyl ester], fatty acids [phytol, methyl isohexadecanoate, palmitic acid, palmitic acid methyl ester, (9,12-Octadecadienoic acid, ethyl ester), (9Z, 12Z, 15Z�Octadecatrienoic acid, ethyl ester)], and organosilicon compounds [silicic acid, diethyl bis(trimethylsilyl) ester and cyclotrisiloxane, hexamethyl] detected in shoot and root extract were similar in some compounds, however, they show difference in phytotoxicity. 125 mg/ml of shoot aqueous extract and 0.5 mg/ml of fraction (B) shoot were the highest concentrations that affected the germination of weeds. The results show that Imperata cylindrica contains allelochemical compounds that are released from the root and shoots parts under different favorable conditions have the capability to contribute towards inhibition and stimulation in germination, lengths growth and decrease in the biomasses of other plant species

Computer aided analysis of flow and pressure in pipe networks

Pipeline systems range from the very simple to very large and quite complex ones. They may be as uncomplicated as a single pipe conveying water from one reservoir to another or they may be as elaborate as an interconnected set of water distribution networks for a major metropolitan area. Individual pipelines may contain several kinds of pumps at one and or at an intermediate point; they may deliver water to or from storage tanks. A system may consist of a number of sub-networks separated by differing energy lines or pressure levels that serve neighbourhoods at different elevation, and some of these may have pressurised tanks so that the pumps need not operate continuously. In order that these transfer systems will adequately fulfil their intended functions, they may require the inclusion of pressure reducing or pressure sustaining valves. These days an understanding of some particular numerical method and the ability to implement them on a computer, for obtaining solutions for a large problem is a vitally needed skill. Computations associated with engineering practice have changed dramatically in the past quarter century from the estimation of a few key values by using a slide rule to the generation of pages of computer output that are the result of detailed simulations of system performance. In the steady state analysis and design of networks, a large system of non-linear equation must be solved. In these work a computer program has been developed which carries out the regular simulation of steady state pressure and flow in pipe system. The computer program is written in C Language, to solve the basic pipe system equations using linear method. Basically the program reads input data defining the parameter for each pipe and each junction in the network. Connecting node number is the only geometric data in put for each pipe. From this data, the basic system equations are generated and solved