Sharif Digital Repository

Considering their special features and numerous applications, sensor networks are noticed so much nowadays. A sub-group of these applications is underwater sensor networks, which encounter some challenges like reliable transportation, routing, MAC, positioning, limited bandwidth, high and variable propagation delay, defective underwater channels and low battery capacity. Acoustic technologies are a particular technology which can make strong underwater communications for Civilian and military applications. These networks are used in oceans for environmental monitoring, under sea discovery, unexpected events prevention, ships assisting, tactical monitoring and naval mine detection, but there... 

The necklace hypercube has recently been introduced as an attractive alternative to the well-known hypercube. Previous research on this network topology has mainly focused on topological properties, VLSI and algorithmic aspects of this network. Several analytical models have been proposed in the literature for different interconnection networks, as the most cost-effective tools to evaluate the performance merits of such systems. This paper proposes an analytical performance model to predict message latency in wormhole-switched necklace hypercube interconnection networks with fully adaptive routing. The analysis focuses on a fully adaptive routing algorithm which has been shown to be the most... 

In this paper, we propose the Object Pursuing based Efficient Routing Algorithm (OPERA) suitable for vehicular ad hoc networks (VANETs), esp. in sparse situations. The proposed algorithm is applicable for both moving and fixed destinations. It is based on considering static nodes at each intersection. In this algorithm, we optimize the decision making at intersections, with respect to the connectivity and feasibilty of the roads. To this end, we consider the average delay of each road as the connectivity metric, and the vehicle availability in the transmission range of the intersection as the feasibility metric. By exploiting the related metrics, we select the next road to forward the packet... 

Irregular networks provide more scalability and better cost-performance for network-based parallel computing systems. There has been much work done on developing routing algorithms for this class of networks. In this paper, a general methodology for generating deadlock-free routing algorithms for irregular networks is proposed. It not only introduces three novel efficient routing algorithms, but also covers the three best-known routing algorithms already proposed for irregular networks in the literature, namely Up/Down, Left/Right, and L-turn routing algorithms. As revealed by simulation results, the performance of the six routing algorithms mainly depends on network topology and different... 

Irregular topologies are desirable network structures for building scalable cluster systems and very recently they have also been employed in SoC (system-on-chip) design. Many analytical models have been proposed in the literature to evaluate the performance of networks with different topologies such as hypercube, torus, mesh, hypermesh, Cartesian product networks, star graph, and k-ary n-cube; however, to the best of our knowledge, no mathematical model has been presented for irregular networks. Therefore, as an effort to fill this gap, this paper presents a comprehensive mathematical model for fully adaptive routing in wormhole-switched irregular networks. Moreover, since our approach... 

Knowing the capabilities of game theory in analyzing environment consisting of many decisionmakers or agents, it has been the goal of many researchers to apply Game Theory analyses in computer and telecommunication networks. One of the main subjects in the networks based on the viewpoint of Game Theory is routing problems in special networks. In this paper, routing in Wireless Mesh Networks, which are growing and developing rapidly, is studied as an example for routing in computer and telecommunication networks and a new model for such networks is proposed based on Non-cooperative Game Theory. It is proposed to solve this model by a heuristic method essentially based on simulated annealing... 

Improvement of energy efficiency in Software Defined Networking (SDN) is a challenging problem. In order to achieve higher energy efficiency, the routing and scheduling in software defined networks should be planned robustly based on the topological specifications of the SDN. The topological specifications of the SDN depends on the size of the network graph which changes rapidly as the virtualized network devices in the network turned on and off by the controller. Therefore, modelling the SDN graph is an important issue in designing a reliability aware energy efficient SDN. In this paper we propose a new algorithm for reliable energy efficient traffic engineering in SDN. In the proposed... 

This paper presents an extension to PathFinder FPGA routing algorithm, which enables it to deliver FPGA designs free from risks of crosstalk attacks. Crosstalk side-channel attacks are a real threat in large designs assembled from various IPs, where some IPs are provided by trusted and some by untrusted sources. It suffices that a ring-oscillator based sensor is conveniently routed next to a signal that carries secret information (for instance, a cryptographic key), for this information to possibly get leaked. To address this security concern, we apply several different strategies and evaluate them on benchmark circuits from Verilog-to-Routing tool suite. Our experiments show that, for a... 

Recently, routing with disjoint paths has received much attention to provide more performance and fault tolerance. On the other hand, WK-recursive mesh network has been studied extensively due to its favorable properties such as high degree of stability and resilience. The connectivity of a network is an important measure of fault tolerance, while the diameter represents the worst-case transmission delay between two arbitrary nodes. In this paper, we propose one-to-one and one-to-many disjoint routings mechanisms for WK-recursive mesh networks to further exhibit the performance and fault tolerance of such networks. © 2008 IEEE  

There are two strategies for deadlock handling in routing algorithms in NoC: deadlock avoidance and deadlock recovery. Some deadlock recovery routing algorithms are re-injection based, such as: Compressionless (CR), Software-Based (SW-TFAR) and AFBAR. In spite of the performance comparison, none of existing researches have focused on the energy consumption of various routing algorithms. We evaluate these routing algorithms according to their energy consumption and latency. Our experimental results show the better performance and worse energy consumption of deadlock recovery routing algorithms compared to deadlock avoidance routing algorithms. In addition, the best and worst energy... 

Active Queue Management (AQM) policies provide an early indication of incipient congestion to the source. In this paper, we propose a new AQM policy that predicts the instantaneous queue length at the next time instant using adaptive filtering technique. To use this algorithm in fast routers, we have reduced its computational complexity. The proposed method uses a simple linear function as adaptive rule. We show that this adaptive congestion control method is able to control the oscillations in the instantaneous queue length. We compare the performance of our method with the other well-known AQM methods such as RED and PI which are also simulated by MATLAB. We also compare the computational... 

In this paper, we compute lower and upper bounds for the throughput capacity of an ad hoc network overlaid on a cellular network. The ad hoc network is comprised of a specific number of wireless cognitive nodes that opportunistically exploit the inactive frequency channels in the cellular network. In this respect, we employ a model recently proposed for single-channel mobile ad-hoc network after some minor modifications. The proposed framework consists of two queueing networks, a closed BCMP queueing network comprised of M/G/∞nodes capable of mobility modeling, and an open BCMP queueing network comprised of symmetric M/G/1 nodes capable of modeling the packet transmission process. By... 

Despite FPGAs rapidly evolving to support the requirements of the most demanding emerging applications, their high static power consumption, concentrated within the routing resources, still presents a major hurdle for low-power applications. Augmenting the FPGAs with power-gating ability is a promising way to effectively address the power-consumption obstacle. However, the main challenge when implementing power gating is in choosing the clusters of resources in a way that would allow the most power-saving opportunities. In this paper, we take advantage of machine learning approaches, such as K-means clustering, to propose efficient algorithms for creating power-gating clusters of FPGA... 

Although many Dynamic Thermal Management (DTM) techniques are employed to overcome thermal problems in 3D NoCs, none of them consider temperature information of all nodes of a layer at the same time, so that they cannot reduce the temperature of the network properly.To overcome this problem, this paper proposes an efficient proactive thermal-aware routing algorithm, called Less Entrance to Hot Regions (LETHOR), to keep the NoC temperature lower than a predefined thermal limit. LETHOR routes the network packets based on the temperature information of all nodes in the layers instead of considering only the neighbor nodes in each hop. To this aim, LETHOR introduces a Hot Region in each layer... 

Heterogeneity is one of the challenges in the current NoC design which forces designers to consider irregular topologies. Therefore, finding an optimal topology with minimum cost (minimum use of links, buffers, NIs, etc) and power consumption, and maximum flexibility can provide the best cost-performance trade-off. Irregular mesh is a topology which combines the benefits of regularity and advantage of irregularity. Routing algorithms especially those coupled with wormhole switching should deal with deadlock occurrences. Unlike deadlock avoidance-based schemes, deadlock detection and recovery-based routing schemes, do not restrict routing adaptability. In this paper, we modify irregular mesh... 

In this paper, we propose a new architecture for nanophotonic Networks on Chip (NoC), named 2D-HERT, which consists of optical data and control planes. The proposed data plane is built upon a new topology and all-optical switches that passively route optical data streams based on their wavelengths. Utilizing wavelength routing method, the proposed deterministic routing algorithm, and Wavelength Division Multiplexing (WDM) technique, the proposed data plane eliminates the need for optical resource reservation at the intermediate nodes. For resolving end-point contention, we propose an all-optical request-grant arbitration architecture which reduces optical losses compared to the alternative... 

In this paper, an underwater wireless sensor network (UWSN) is modeled with the help of queueing theory in order to evaluate the maximum stable throughput of the network. To this end, a new scenario for multi-layer mobile UWSN is considered. Then, a new MAC algorithm comprised of random access scheme (like MACAW) and CDMA-based data transmission along with a simplified routing algorithm is proposed. In order to analyze the considered UWSN scenario, we propose two related queueing networks, one for modeling the wireless node mobility and the other for representing the process of multi-hop packet transmission according to considered MAC and routing algorithms. Finally, the maximum stable...