Network coding (NC) is an approach for increasing the throughput of communication networks. NC has been derived from the idea of combining packets and forwarding them to achieve higher throughputs. From the very beginning, NC has attracted the attentions of scholars since they could improve the throughput of wired networks. Previous works have focused on the improvement of network throughput. Some methods add artificial delay to send packets. The methods are used in order to gain coding time and to increase throughput but they could not be used in immediate applications. However, early packets dispatch or adding delay to packets, for increasing coding time, can influence on the jitter of sent data. On the other hand, jitter is an important parameter in determining multimedia broadcasting time. Unlike previous methods, this paper provides a jitter-based coding algorithm using Jacobsen method. In the proposed method, the selection priority is based on packets jitter so that a packet with the minimum jitter is considered as the first priority for coding. Related computations are performed through Jacobson algorithm. According to simulation results, selecting a proper coding pattern for jitter can improve jitter by 30% while the throughput of this method shows no considerable change compared with that of available methods.

Nowadays with the growth of organizations and their affiliates, the importance of information systems has increased. Functional and non-functional requirements of information systems in an organization are supported. There are literally several techniques to support the functional requirements in terms of software methodologies, but support for the second set of requirements has received little attention. Software Performance Engineering (SPE) forum tries to address this issue by presenting software methodologies to support both types of requirements. In this paper, we present a formal model for the evaluation of system performance based on a pragmatic model. Because of supporting the concurrency concepts, petri net has a higher priority than queuing system. For mapping UML to colored Petri net diagram, we use an intermediate graph. The preliminary results indicate that the proposed model may save significant amount of computations.

This paper presents a new basic clustering algorithm to increase the wireless sensor networks energy and longevity, efficiently. In each period, cluster heads are selected based on the maximum energy and the minimum distance through the nodes. Therefore, the protocol to obtain good performance in terms of longevity is achieved by balancing the energy load among all nodes. The simulation results obtained from the MATLAB software indicate that the suggested approach is effective in prolonging the network longevity.

The Ad hoc network is one of the multistep-based self-organizing networks, which are dynamically changing and are taken more into account as the ways of connecting the terminals through the development of wireless communication terminals. We are faced with numerous challenges in designing a wireless network such as the dynamic topology, common and limited bandwidth, and the limited energy. The nodes are moving according to the continuous changes in the topology and the source-to-destination paths are completely broken. Therefore, the repeated route discovery enhances the delay and overload of routing. Thus, it is essential to consider the link stability while designing the path in order to choose the routing protocol. Providing the multiple paths may lead to the better performance than a path. The transmission energy control in the wireless Ad hoc networks is the option for the level of transmission energy in order to transmit each node packet in this system. Therefore, transmission energy control affects the wireless medium interface. Because of choosing the appropriate protocol, the routing operation can be improved and the energy consumption can be controlled properly as well as enhancing the durability and longevity of network. The main objective of this study is to enhance the network longevity. The proposed algorithm in this research considers the combination of 2 parameters including the rate of node energy and number of steps in Fuzzy System applied on AOMDV Protocol, which is a Multipath Routing Protocol. The results of simulation also indicate the improved performance of proposed algorithm (AOMDV-F) compared to AODV and AOMDV Protocols in NS2 simulator.

These days, There are several applications where we face with large data set and it has become an important part of common resources in different scientific areas. In fact, there are many applications where there are literally huge amount of information handled either in terabyte or in petabyte. Many scientists apply huge amount of data distributed geographically around the world through advanced computing systems. The huge volume data and calculations have created new problems in accessing, processing and distribution of data. The challenges of data management infrastructure have become very difficult under a large amount of data, different geographical spaces, and complicated involved calculations. Data Grid is a remedy to all mentioned problems. In this paper, a new method of dynamic optimal data replication in data grid is introduced where it reduces the total job execution time and increases the locality in accessibilities by detecting and impacting the factors influencing the data replication. Proposed method is composed of two main phases. During the first phase is the phase of file application and replication operation. In this phase, we evaluate three factors influencing the data replication and determine whether the requested file can be replicated or it can be used from distance. In the second phase or the replacement phase, the proposed method investigates whether there is enough space in the destination to store the requested file or not. In this phase, the proposed method also chooses a replica with the lowest value for deletion by considering three replica factors to increase the performance of system. The results of simulation also indicate the improved performance of our proposed method compared with other replication methods represented in the simulator Optorsim.

Software Architecture (SA) is one of the most important artifacts for life cycle of a software system because it incorporates some important decisions and principles for the system development. On the other hand, developing the systems based on uncertain and ambiguous requirement has been increased, significantly. Therefore, there have been significant attentions on SA requirements. In this paper, we present a new method for evaluation of performance characteristics based on a use case, response time, and queue length of SA. Since there are some ambiguities associated with considered systems, we use the idea of Fuzzy UML (F-UML) diagrams. In addition, these diagrams have been enriched with performance annotations using proposed Fuzzy-SPT sub profile, the extended version of SPT profile proposed by OMG. Then, these diagrams are mapped into an executable model based on Fuzzy Colored Petri Nets (FCPN) and finally the performance metrics are calculated using the proposed algorithms. We have implemented CPN-Tools for creating and evaluating the FCPN model.

A mobile ad hoc network (MANET) is considered as an autonomous network, which consists of mobile nodes, which communicate with each other over wireless links. When there is no fixed infrastructure, nodes have to cooperate in order to incorporate the necessary network functionality. Ad hoc on Demand Distance Vector (AODV) protocol is one of the primary principal routing protocols implemented in Ad hoc networks. The security of the AODV protocol is threaded by a specific kind of attack called ‘Black Hole’ attack. This paper presents a technique to prevent the Black hole attack by implementing negotiation with neighbors who claim to maintain a route to destination. Negotiation process is strengthen by apriori method to judge about suspicious node. Apriori algorithm is an effective association rule mining method with relatively low complexity, which is proper for MANETs. To achieve more improvement, fuzzy version of ADOV is used. The simulation results indicate that the proposed protocol provides more securable routing and also more efficiency in terms of packet delivery, overhead and detection rate than the conventional AODV and fuzzy AODV in the presence of Black hole attacks.

Mobile Ad hoc Network (MANET) consists of some nodes, which are randomly placed in operational environment. This type of network does not have any infrastructure and nodes are completely dynamic and moveable. Each node can contact with the other in-range nodes. One of the disadvantages of MANET is the low lifetime of nodes power in which the energy consumption of the network goes up due to connectivity overheads. In this paper, by presenting a Fuzzy clustering algorithm, we endeavor for a more optimized energy consumption of this network by reducing the number of re-election of clusterheads (CHs) and reducing the re-affiliation of nodes and also by selecting the best node as CH amongst current members of each cluster. The result of simulation shows that our algorithm performs better than other existing algorithm.

Architecture includes so many documents where each describes one part of an enterprise. The problem in using such descriptions is on how to consider and use all components. Therefore, in order to organize the descriptions of enterprise architecture, we should use a framework. C4ISR is one of the enterprise architectural frameworks, which includes three views, contains some products. In order to show the products, this framework needs a unified notation, which covers all the products with various views. Unified Modeling Language (UML) prepares such situation. But in order to decrease the expenses of enterprise architectural productions process, the architectural products shall be evaluated before the architectural implementation level happens. In this article, a simple way for validation of enterprise architectural products with Colored Petri Nets is presented to evaluate true behavior of architectural products well.