Computer And IT

Today's data centers consist of thousands of servers hosting a variety of cloud-based services. In this paper, a scalable and new technique is presented for traffic engineering in software-defined data center networks helping to design an optimal demand-path mapping with a tolerable computational complexity. The proposed method is based on linear programming model and attempts to minimize the maximum link utilization that causes minimum link congestion. The method focuses on an optimal solution to load balancing in networks. It proposes a new decomposition technique that can limit the search space of the original Linear Programming problem, such that the time required to solve the problem can be reduced substantially. To reduce time complexity, a decomposition technique is used to divide the problem model into smaller sub-problems, which are then solved simultaneously by applying parallelizing techniques (multiple-core computing and OpenMP).Simulation results show that solving time and load balancing are considerably improved.

Mobile ad hoc networks communicate in a self-organized way without depending on any fixed infrastructure. The issue of selfish nodes, which may refuse to cooperate, is a great challenge in such networks and may cause network throughput to drastically reduce. Energy-based selfishness is a category of selfishness in which a selfish node shows nondeterministic and probabilistic selfishness behaviors based on level of its energy. In this paper, we propose a mechanism for coping with this kind of selfishness. This mechanism called CEMDEEM not only detects and isolates energy-based and traditional selfish nodes, but also malicious behaviors like spoofing. We also evaluate performance of Dynamic Source Routing (DSR) protocol fortified by CEMDEEM in the presence of different percentages of selfish nodes. Results show that CEMDEEM noticeably improves network performance with a reasonable additional packet overhead and network delay especially when percentage of selfish nodes is not more than 40.

Today's data centers consist of thousands of servers hosting a variety of cloud-based services. In this paper, a scalable and new technique is presented for traffic engineering in software-defined data center networks helping to design an optimal demand-path mapping with a tolerable computational complexity. The proposed method is based on linear programming model and attempts to minimize the maximum link utilization that causes minimum link congestion. The method focuses on an optimal solution to load balancing in networks. It proposes a new decomposition technique that can limit the search space of the original Linear Programming problem, such that the time required to solve the problem can be reduced substantially. To reduce time complexity, a decomposition technique is used to divide the problem model into smaller sub-problems, which are then solved simultaneously by applying parallelizing techniques (multiple-core computing and OpenMP).Simulation results show that solving t...

Nanotechnology is providing a new set of tools for designing and creating advanced devices for the realm of engineering. These advanced devices have capabilities for producing, processing and transmitting multimedia content at the nanoscale. By the advent of internet of Nano things, it is necessary to define service models that can classify useful applications of internet of Nano things and determine QOS parameters to satisfy the requirements of these services. Since wireless sensor networks constitute the main component of internet of Nano things, they have become a key factor in providing quality services. In this article, we investigated service quality parameters in internet of Nano things and discussed great challenges of research in the realization of the new networks paradigm of internet of Nano things which had limitless applications in different fields.

Having a healthy life both physically and psychologically depends on physical activities and participation in sports activities. Now, 5 to 15 percent of children have hidden movement disorders. These children are at risk of obesity due to poor movements, musculoskeletal disorders and psychological damages such false self-confidence. In recent decades, a factor that has exacerbated these conditions is traditional computer games. In contrast, modern computer games based on virtual reality technology creates a new experience in raising motor development, coordinating neuromuscular, increasing physical activities and improving mental health in children. In this article, we investigated the use of virtual reality to improve physical and mental health of children and discussed the role of this technology to improve children's health.

It can be understood by the motto of six flags over Texas that historically different governments such as Spain, France and Mexico have ruled over the whole or part of this state. During this time the culture of the people living in the state of Texas has undergone several cultural changes. Now, even though the state of Texas has been a part of United States of America and is run by its central government, it is influenced by different cultures of Spanish, French and Mexican. If people or families have migrated from different parts of the world by educational or occupational purposes, they can be affected by these differences in cultures. Although children from these families are at their critical periods of language learning and at the stage that enculturation can easily take place, they usually play with children of families from other cultures and are influenced by their customs and cultural values which led to acculturation. One of the challenges American families who are forced to migrate to the southern state of America is acculturation. In this article, we examine this challenge and control other countries cultural influences on our children by using virtual reality technology, environments and games which are designed based on such technology.

In the past, the term E-learning was called to all educational methods in which electronic methods was used. By the advent of the Internet, E-learning has evolved and this term is now referred to the online courses. Nowadays, there are many systems for online education but often these systems are single-user environments where there is no stimulation for learning and learner hasn't any communication with education system. Current surveys show that recently many people have had tendency to participate in online training courses therefore researchers are continuously investigating innovative techniques in order to enhance motivation and learning among users who make use of such education systems. In this article for developing these studies, we will review, develop a smart and communicative learning environment by the use of virtual reality, consider its impact on the improvement of second language learning particularly English and take advantage of this system in current educational environment.

Nowadays, numerous studies have been conducted regarding the use of virtual reality technology. This technology has been used widely in various fields such as education, industry, military science and etc. The domain of this investigation is ascending day by day and is expanding so that today this technology can be used in other areas such as museums and cultural centers. By the fact that culture is interwoven to the roots of life, manners and ways by which we live, we can make attempts to come back to ourselves with culture revitalization through virtual reality technology. Due to the importance and continues investigations in this regard, in this article we have discussed the use of virtual reality technology in culture and its impact on cultural revitalization of indigenous tribes in Canada.

Cloud computing and internet of things are quite different technologies that currently form part of our life. It is expected that in the future, these two technologies will be an integrated part of the internet and they will be used more extensively. Internet of things is composed of a high number of nodes that exist in various geographical places and it employs the internet as a key infrastructure to connect and communicate with others. Regarding that data collected via a set of nodes in the internet of things are of a high volume, cloud computing is used as a support infrastructure to keep and process this information. In the literature, the set of nodes in the internet of things and cloud computing are called CloudIot. In this study, integration drivers of cloud computing and the internet of things are addressed and the challenges facing this technology are investigated.

Grid computing is a new technology the objective of which is to share resources including processor, hard disk, software etc. in a dynamic, heterogeneous, and large-scale environment. This sharing is mainly employed to solve computing problems in academic and industrial settings. Reliability of grid computing is very important considering it's growing use and development in sharing resources in dynamic and large-scale environments with heterogeneous composition. In this study, with regard to the basis of grid i.e. resource management, grid reliability and advances made in achieving this goal are investigated. In addition, problems of the reliability of grid computing system in large-scale, heterogeneous, and dynamic environments are also investigated.

Cloud computing is predicted as the architecture of IT services for the next generation. In cloud computing, applications and databases are focused in large data centers where data and service management are not fully reliable. This will bring new security challenges that are not well-understood. One of the main issues that results in users' uncertainty to use services of cloud computing, is to ensure the integrity of their data saved in cloud storage. In this study, various models presented to verify and confirm data security are investigated using which data owners can be convinced that their data are saved in cloud storage correctly.

Rapid adoption of the Internet of Things (IoT) as an integrated part of daily life and its openness increase security concerns about independent objects with the features of knowledge sharing to perform personal or collective tasks. In this study, problems and security holes available in communication technologies used in the relationships between things and the Internet of Things are analyzed and investigated that have a great impact on the privacy of users who are using the Internet of Things.

Despite advances in computer industry in various affairs, wishes and dreams of this science in assisting people in their daily lives and in different environments are not far-fetched. Up to now, different technologies are presented to collect various types of information from the environment and comprehensive studies are conducted in various fields to realize this goal, i.e. assisting people in their daily lives. Achieving this goal depends on realization of ambient intelligence (AmI). Ambient intelligence is a science through which the whole environment is covered by intelligence. In this study, the ability of ambient intelligence in timing of password change and its effect on increasing security are investigated.

Grid is a new technology and a distributed and parallel system the aim of which is to share resources including processor, hard disk, software etc. in a dynamic, heterogeneous, and large-scale environment. This sharing is mainly employed to solve problems like computational problems academic and industrial settings. Timing and load balancing are two major aspects in grid. Therefore, in this study it has been attempted to present a cluster-based hybrid algorithm with better performance compared to other presented algorithms to improve execution time of tasks in global networks, while investigating timing algorithms presented recently in global grid.

Grid is a new technology and a distributed and parallel system the aim of which is to share resources including processor, hard disk, software etc. in a dynamic, heterogeneous, and large-scale environment. This sharing is mainly employed to solve problems like computational problems academic and industrial settings. Timing and load balancing are two major aspects in grid. Therefore, in this study it has been attempted to While investigating timing algorithms that are recently expressed in global grid, a hybrid evolutionary algorithm based on balanced ant colony optimization with a better performance relative to other was proposed algorithms, was presented to improve execution time of tasks in global grid.

To run users' applications, global grid use a large number of dynamic, distributed and heterogeneous resources that are controlled and supervised by various organizations. Here, task scheduling becomes an NP-complete problem despite limitations imposed by users to the system (namely cost and time deadlines). Therefore, considering that metaheuristic algorithms are highly efficient to solve NP-complete problems, in this study, while investigating various scheduling algorithms proposed recently in this regard, we have attempted to suggest a scheme that provides us with benefits including reduced time complexity of search and its easy implementation by combining meta heuristic genetic and colonial competitive algorithms. Results of simulation conducted in a fair environment using MATLAB simulation tool showed that compared to other algorithms presented recently related to task scheduling in global grid, the proposed algorithm prevents premature convergence and a pause in local minimums and it ensures global optimality while improving task scheduling.

Grid is a distributed and parallel computational system where scheduling and load balancing are two important issues. Scheduling in a grid is a sort NP-hard problem considering the dynamism and diversity of resources, its uncertain nature and limitations defined by users for it. Therefore, to solve this problem, an uncertain and meta-heuristic algorithm is required to obtain a near-optimum response. Therefore, numerous studies have been conducted on meta-heuristic algorithms including genetic algorithm. In this study, it was attempted to propose a method to improve task scheduling based on genetic algorithm. In the proposed method, an evolved architecture with two independent global and local schedulers is employed where first the network structure is divided into zones based on the distance of resources from global scheduler. Then, by combining small sub clusters of resources in each zone, the main sub cluster is formed. In this method, genetic algorithm is used to select the main cluster and attribute tasks to it with the aim of ensuring load balance using threshold value and scheduling the main cluster. Results of simulation in a fair environment using MATLAB simulation tools showed that in addition to an 8% decrease in task completion time, a 21% decrease in distance and a 16% improvement in bandwidth used, the proposed method prevents premature convergence and a pause in local minimums and it ensures global optimality, compared to the best method (ECPSO) investigated recently in relation to task scheduling in grids.