The Intelligent Transportation System (ITS) provides wireless and mobile communication between vehicles and infrastructure to improve the safety of transportation and make the journey more enjoyable. This system consists of many fixed and mobile nodes (Vehicles, Trains, Vessels, Air planes), Wireless and Wired Telecommunication Technologies to exchange information between mobile nodes or between mobile nodes and fixed stations. The most common transportation tools are cars. Vehicular Ad-hoc Networks as an Application of Mobile Ad-hoc Networks and one of the subsets of Intelligent Transportation System provides wireless Ad-hoc communication between vehicles. VANET is a mobile wireless technology which is designed to improve safety of transportation with exchanging real time data between vehicles and providing different services to the users. It has special characteristics like high mobility and provides a broad range of services to the users, so it has been emerged as one of the research interests in the field of computer and telecommunication networks. In This paper we present different aspects of ITS and VANET to help the researchers to understand the Architecture, Communication Technologies and Applications of these networks. تفاصيل المقالة

The systems in which information and communication technologies and systems engineering concepts are utilized to develop and improve transportation systems of all kinds are called “The Intelligent Transportation Systems (ITS)”. ITS integrates information, communications, computers and other technologies and uses them in the field of transportation to build an integrated system of people, roads and vehicles by utilizing advanced data communication technologies. Vehicular Ad-hoc Networks which is a subset of Mobile Ad-hoc Networks, provide Vehicle to Vehicle (V2V), Vehicle to Roadside (V2R) and Vehicle to Infrastructure (V2I) communications and plays an important role in Intelligent Transportation System. Due to special characteristics of VANETs, QoS (Quality of Service) provisioning in these networks is a challenging task. QoS is the capability of a network for providing superior service to a selected network traffic over various heterogeneous technologies. In this paper we present an overview of Vehicular Networks, QoS Concepts, QoS challenges in VANETs and approaches which aim to enhance the Quality of Service in Vehicular Networks تفاصيل المقالة

Cloud computing is a result of the continuing progress made in the areas of hardware, technologies related to the Internet, distributed computing and automated management. The Increasing demand has led to an increase in services resulting in the establishment of large-scale computing and data centers, in addition to high operating costs and huge amounts of electrical power consumption. Insufficient cooling systems and inefficient, causing overheating sources, shortening the life of the machine and too much carbon dioxide is produced. In this paper, we aim to improve system performance; Cloud Computing based on a decrease in migration of among virtual machines (VM), and reduce energy consumption to be able to manage resources to achieve optimal energy efficiency. For this reason, various techniques such as genetic algorithms (GAs), virtual machine migration and ways Dynamic voltage and frequency scaling (DVFS), and resize virtual machines to reduce energy consumption and fault tolerance are used. The main purpose of this article, the allocation of resources with the aim of reducing energy consumption in cloud computing. The results show that reduced energy consumption and hold down the rate of virtual machines breach of contract, reduces migration as well. تفاصيل المقالة

Mobile ad hoc networks (MANET) are constructed by mobile nodes without access point. Since MANET has certain constraints, including power shortages, an unstable wireless environment and node mobility, more power-efficient and reliable routing protocols are needed. The OLSR protocol is an optimization of the classical link state algorithm. OLSR introduces an interesting concept, the multipoint relays (MPRs), to mitigate the message overhead during the flooding process. Although very efficient by many points, it suffers from the drawbacks of not taking into account QoS metrics such as delay or bandwidth. To overcome this pitfall, some QOLSR solutions have been designed. IN this paper, we introduce an algorithm for MPRs selection based on Battery Capacity and Link Stability. Simulation results show that our proposed protocol is able to enhance throughput and improve end-to-end delay. تفاصيل المقالة

رایانش ابری محیطی ست ،که کاربران براساس تقاضا و پرداخت به ازای استفاده به منابع محاسباتی اشتراکی دسترسی دارند. با توجه به محدودیت و پویایی منابع محاسباتی برای اجرای درخواست‌های متنوع و متغیر با زمان کاربران، نیاز به یک مکانیزم زمانبندی موثر برای رسیدگی به شرایط پویای سیستم و بهره وری منابع و رضایت کاربران امری حیاتی می باشد. از آنجایی که تخصیص وظایف به منابع یک چالش اساسی در محیط های ابری به شمار میرود الگوریتم‌های بسیاری جهت کاهش زمان اجرا و موازی‌سازی زیروظایف ارائه شده‌ است. الگوریتم‌های زمان‌بندی موجود تلاش می‌کنند با توجه به وضعیت فعلی سیستم، یک زمانبندی بهینه بین منابع و وظایف با توجه به پویایی درخواست های کاربران فراهم آورند، ولی با این وجود اغلب این روش ها نتوانسته اند در بلندمدت نتیجه مطلوبی را ارائه دهند. به دلیل سرعت همگرایی پایین راه‌حل‌ها در الگوریتم‌های فرااکتشافی در این مقاله یک روش زمان‌بندی متناسب با صف‌های اولویت چندگانه مبتنی بر رتبه‌بندی نامغلوب و به کمک الگوریتم بهینه سازی جستجوی کاپوچین برای سیستم‌های ابری ناهمگن ارائه شده است. نتایج شبیه سازی نشان میدهد که روش پیشنهادی در مقایسه با روش های پیشین از نظر تاخیر، توازن بار و زمان اجرا بهتر عمل می‌کند. تفاصيل المقالة