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One of the most challenging issues in cognitive radio networks is efficient channel sensing and channel accessing. In this paper, an analytical queueing model is used to derive the probability of successful transmission, channel sensing time, and transmission quota, for each data channel. Each CR node records the derived statistics in a channel preference matrix. A CR pair selects a data channel for...
Thermal nitrogen oxide (NO) emission is the major pollutant from industrial furnace. High temperature air combustion is an advanced technology to control NO emission, which carries out the combustion at highly preheated air and dilute oxygen conditions. The combustion performance of natural gas with highly preheated air was numerically simulated in an industrial furnace with a longitudinal and swirling...
Cluster formation and cluster head selection are important problems in sensor network applications and can drastically affect the network's communication energy dissipation. However, selecting of the cluster head is not easy in different environments which may have different characteristics. In our previous work, in order to deal with this problem, we proposed a power reduction algorithm for sensor...
Optimization of hard fusion spectrum sensing using the k-out-of-N rule is considered. Two different setups are used to derive the optimal k. A throughput optimization setup is defined by minimizing the probability of false alarm subject to a probability of detection constraint representing the interference of a cognitive radio with the primary user, and an interference management setup is considered...
This paper investigates a novel relaying strategy for cooperative networks over Nakagami-m fading channel, namely selection incremental relaying (SIR), which combines selection relaying (SR) with incremental relaying (IR) based on decode-and-forward (DF). The closed-form expression for the outage probabilities of both single relay and opportunistic relay strategies are derived. Simulation results...
Neighbor discovery is an essential step for the self-organization of wireless sensor networks. Many algorithms have been proposed for efficient neighbor discovery. However, most of those algorithms need nodes to keep active during the process of neighbor discovery, which might be difficult for low-duty-cycle wireless sensor networks in many real deployments. In this paper, we investigate the problem...
Motivated by the problem of multiple unlicensed cognitive radio users seek to access unused frequency channels licensed to the primary users in a wireless communication scenario, this paper presents a simulation environment that is able to simulate various effects of radio wave propagation and shadow fading in a software model. A cognitive radio designer's intent, knowledge about the critical issues...
The cooperative communication makes wireless transmission reliable utilizing special diversity, where the relay selection is one of important issues. In this paper, we propose a relay selection scheme exploiting SNR and success probability of the link between nodes in network, especially focus in the link between the source and the relay. Proposed scheme is compared with previous schemes by the simulation...
Like most reliability and risk analyses, a Probabilistic Risk Assessment (PRA) is most effective when it can be used to influence design decisions in a timely manner. However, development of a PRA can be very resource consuming and its development typically lags design milestones, limiting its usefulness to that of a design verification tool. As the case study described in this paper shows, using...
This paper considers a cluster-based wireless sensor network (WSN) where each sensor node takes turn to be cluster head. The main function of the cluster head is to oversee the communication within and between clusters while the remaining sensor nodes are involved in sensing of the surrounding environment. We address the sensor utilization problem where non-cluster head nodes in a cluster make decision...
A technique to estimate user speed using transmit power control (TPC) commands is presented. We derive a close-form expression of the probability of the derivative of receive signal power exceeding a given threshold as a function of user speed, and show that it has a strong correlation with TPC pattern. The derived equation is used to map between TPC pattern and the corresponding user speed. Simulation...
It is known that the Luby Transform codes provide an efficient scheme to transfer information over erasure channels. These codes are also rate-less and robust against packet losses in a jamming environment. In this paper overcome many weaknesses that this coding technique apprehends. Three weaknesses are observed in three different categories when the equivalent matrix is employed. In fact, such codes...
In a wireless sensor network with relaying capability, intermediate relay nodes are with limited energy budget. To maximize lifetime of relay nodes, selective relay strategies, requiring full channel state information (CSI), are used to utilizes the best relaying channel. Pilot overhead on relay nodes lifetime is reduced by assuming pilot transmission from destination instead of relay nodes. This...
In common models of cognitive radio networks (CRNs), priority in spectrum access of primary users (PUs) must be guaranteed, but the quality of service (QoS) for secondary users (SUs) is mostly ignored. Subject to meeting PUs' blocking probability objective, this paper proposes a channel reservation scheme to enhance QoS for SUs. The proposed scheme employs a centralized control manager (CCM) to coordinate...
Ant colony algorithm is a novel category of bionic meta-heuristic algorithm and it is usually used in the discrete optimization problem and less in the continuous optimization problems.The ant colony algorithm has strong robustness and easy to combine with other methods in optimization. This paper presents an improved ant colony algorithm for the continuous function optimization. Simulated experiments...
Most Vehicular Ad Hoc Networks' (VANET) applications use broadcasting as a main block for safety messages' dissemination. The broadcast range is a critical parameter in the success of any VANET's safety application. Moreover broadcasting in its normal way may lead to a broadcast storm problem. In this paper we present a geometric model to predict the recommended maximum range of a one hop broadcast...
Under the condition that the coverage of each discrete grid point is K and the precision is T, this paper presents a new covering algorithm based on the probability model, the simulation of which can be performed with MATALB. Simulation results show that the least sensors are needed in this new algorithm compared with the mean algorithm and the randomized algorithm.
Femtocells are tiny base stations designed for the improvement of coverage and capacity of the cellular networks. Subscribers can get and install femtocells in their premises to improve the indoor signal or to increase the bandwidth when needed. However, spontaneously and arbitrarily deploying femtocells incurs difficulties of channel allocation and raises the possibility of coverage overlapping for...
Human error plays a significant role in the failure of fastener-style tubular steel formwork-support(FTSF) during construction. Making full use of site investigation and references, the laws of human error occurrences during construction were gained. The probabilistic models for slip bearing capacity of right-angle couplers with different bolt tightening torques were obtained through experimental...
Clustering sensor nodes is an effective topology control for increasing network lifetime and scalability. It also, balances the load on the sensor nodes. HEED is a well known distributed clustering protocol that uses both energy and communication cost to elect Cluster Heads (CHs) in a probabilistic way. This paper improves HEED protocol using fuzzy logic and a non probabilistic approach for CH election...
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