Modelling of routing and spectrum handoff in CR-MANETs

There is an extensive research interest in cognitive radio mobile ad hoc networks (CR-MANETs) to improve the spectrum efficiency by developing innovative design techniques through various layers of the protocol stacks. This paper presents the optimisation of CR-MANETs by exploiting the efficient usage of the available wireless spectrum through a framework for spectrum-aware handoff. In this paper, the concept of integrated handoff management in CR-MANETs is considered. An analytical model for a spectrum handoff scheme is introduced based on spectrum mobility in which secondary users (SUs) will move to another unused spectrum band, giving priority to a Primary User (PU), while satisfying its communication quality of service (QoS). The main contribution is using the Markov chain to model the evolution of the network (node position, node speed, channel quality, etc.) and to propose the combined spectrum handoff and routing. The performance of the network is analyzed based on the Markov chain. The comparison results from both analytical modelling and simulation clearly show an improvement in the performance of the SU network in terms of the route maintenance probability and the SU throughput. It is also proved that not only the PU activity affects the performance of the handoff management scheme but also the channel transmission range and the node mobility have a significant effect on the performance of the management schem

Characterization of spectrum mobility and channel availability in CRMANETs

Cognitive radio (CR) is the most enterprise solution to spectrum scarcity. The time and space varying nature of spectrum bands necessitates the spectrum handoff in which the secondary user (SU) must vacate the frequency band when the primary users (PUs) reuse the spectrum band. The variation in spectrum band is called spectrum mobility. Hence, characterization of spectrum mobility and channel availability, which is the most influential factor in CR networks, is essential. In this paper, we investigate an analytical model to show the effect of different events on channel availability and spectrum mobility in mobile cognitive radio Ad hoc networks (CR-MANETs). We also integrate the effect of different events on the channel availability, which is essential for performing integrated mobility and handoff management

Virtual power plants planning in the distribution network constrained to system resiliency under extreme weather events

The present study finds the proper location and size of virtual power plants (VPPs) in distribution networks, while taking into account network resilience to severe weather conditions. This is formulated as an optimization problem with two objective functions to minimize both the planning cost of the VPPs in a year and expected energy not-supplied of the network during natural events like flood and earthquake. The problem is subject to some boundaries, including AC power flow relationships, limits on operating and resilience situation, and planning terms of the VPP. There are also uncertain quantities present in the problem, such as those related to the amount of load, renewable power generation, price of energy, and accessibility of equipment and VPP devices. The uncertainties are modeled using the stochastic programming. The two objectives are merged to be a single objective by adopting Pareto optimization based on ɛ-constraint method. Krill herd optimization (KHO) and grey wolf optimization (GWO) are also combined to introduce a new hybrid algorithm so that a dependable optimal solution that shows low dispersion. Finally, a 33-bus distribution network is used to test the validity of the proposed method. According to the result, the optimal size and site of VPPs are found and the network achieves more suitable economic, operating, and resilience indices

Presenting a Meta-Heuristic Algorithm to Detect Regulatory Elements in the Genome of Breast Cancer Patients

Background & Objective: Nowadays, in medical sciences, the amount of data on symptoms of people affected with various illnesses on one hand, and finding assistive techniques for the diagnosis of those diseases on the other, has been widespread. Consequently, the analysis and consideration of all factors involved in a disease are often challenging. Thus, a mechanized system to help discover the rules, identify patterns, and predict future events is absolutely needed. In this research, we intend to use a multi-objective algorithm to provide a method capable of detecting, extract sequences of variable-length from the genome, and count the interactions among them. In fact, these regulatory elements could play a significant role in the incidence and exacerbation of cancer. Material & Methods: In this research, a proposed method for the detection of regulatory elements in the genome of a breast cancer patient has been used. The proposed method is implemented in MATLAB software. Also, to measure the performance and effectiveness of the suggested method, the proposed algorithm is implemented on HiC dataset, regarding patients with breast cancer in two blood cells GM12878 and CD34+ introduced by Mifsud et al. Results: The results of implementing the proposed method are compared with the HiCUP method. The results show that the MSARE method has a better performance in detecting regulatory elements compared to the HiCUP method. Conclusion: Experimental studies have shown that the two promoters BLC6 and HOTTIP discovered by the proposed method have had a significant effect on the incidence and severity of breast cancer in both blood cells GM12878 and CD34+

PUSH: proactive unified spectrum handoff in CR-MANETs

In this paper, Proactive Unified Spectrum Handoff (PUSH) scheme in cognitive radio mobile ad hoc networks (CR-MANETs) through an established route is considered in which the channel availability depends on the Primary User's (PU's) activity, secondary user's (SU's) mobility, and the channel heterogeneity. First, an analytical model for Unified Spectrum Handoff (USH) scheme is introduced in which the SUs will move to another unused spectrum band, giving priority to a PU. Then, the PUSH method is proposed in which a handoff threshold is used to initiate the handoff proactively. When a channel handoff cannot be performed due to the SU's mobility, a local flow handoff (LFH) is performed. The proposed PUSH algorithm uses the cognitive link availability prediction while considering the PU interference boundary to estimate the maximum link accessibility period. Based on the analytical model, the channel heterogeneity and the SU's mobility affected the performance of the handoff management method rather than the PU's activity. Both the simulation and analytical results demonstrated an improvement of route maintenance probability based on the LFH and cognitive link availability prediction mechanisms in PUSH

Proactive integrated handoff management in CR-manets: a conceptual model

In cognitive radio (CR), CR users or also known as secondary users (SUs) are considered as 'visitors' to the licensed spectrum. During the case when the primary user (PU) claims the band of the spectrum that is occupied by the SU, the SU's ongoing call must be transferred to another unused spectrum band. The variation in spectrum band is called spectrum mobility. Spectrum mobility leads to a new handoff in cognitive radio networks, namely spectrum handoff, in which the SUs handover their spectrum band and continue their ongoing calls on an unused spectrum band with different frequency upon the appearance of the PU. In this paper, we investigate a new concept of integrated handoff management in mobile cognitive radio Ad hoc networks (CR-MANET), along with a conceptual framework, its connections and related handoff algorithm