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Software Defined Networking (SDN) expands the networking capabilities using abstraction, open-source protocols, energy efficiency, and programmable features for controlling the forwarding devices at the network edges and intensifying the network performance. Despite all the unprecedented features, SDN still might get exploited by an attacker to launch Distributed Denial of Service (DDoS) attacks at SDN planes i.e. Application, Control, and Data planes. Substantially, the DDoS attacks have been implemented by sending volumetric malicious traffic to exhaust the targeted resources. Such attacks can be easily observed and detected due to their high packet rates. Thus, now attackers are fascinated by the Low-Rate DDoS (LR-DDoS) attacks. In recent years, many efforts have been devoted to defending against the DDoS attacks in SDN. As the attackers benefit from the programmable nature of SDN, an in-detail review of various DDoS attacks and their corresponding defense approaches are essential. Initially, this paper presents a conceptual architecture of SDN and discusses the vulnerable locations in each plane that are exploited by the attacker for launching the DDoS attacks. Secondly, the work offers a detailed classification of DDoS attacks (HR-DDoS and LR-DDoS) concerning the SDN planes and the corresponding defense solutions. The convergence point of this research work is to discover the related security issues and stimulate the network researchers to counter these issues by employing the respective SDN DDoS defense solutions efficiently. Finally, the work gets concluded with a focus on the respective future challenges. [ABSTRACT FROM AUTHOR]

This manuscript proposes a novel technique of synchronization to synchronize four non-identical chaotic systems together. The newly introduced scheme is named as anti-difference quadratic compound synchronization. We have also used the multi-switching of signals to increase the complexity of the proposed scheme. Lorenz, Rössler, and the modified financial systems are taken as drive systems, and the modified Shimizu–Morioko system is taken as the response system to illustrate the obtained results. Lyapunov stability is used to design suitable controllers. Numerical simulations and graphs are presented using MATLAB to verify the theoretical results. [ABSTRACT FROM AUTHOR]

There have been a number of new technologies and applications that can track various events and activities in a variety of environments. Software Defined Networking (SDN) is one of these technologies that has the ability to bring the unanticipated changes in the networking space. SDN aids in the implementation and management of new networks, lowering associated expenses. SDN's unique characteristics make it ideal for monitoring the harsh environmental conditions. Agriculture, Military, Industry, Natural disasters, Health monitoring, Crisis response, and Emergency management are just few examples of common applications. In the last few decades, some of these applications have been of critical relevance and the subject of ongoing research. SDN becomes increasingly popular owing to its perfect benefits, which include aid in various surveillance scenarios. Thus, this survey covers several areas of surveillance and assists the readers to have a better grasp of SDN-based surveillance. Furthermore, various open research problems and the related surveillance challenges have also been explored. [ABSTRACT FROM AUTHOR]

This research article mainly focuses on the development of a new six-dimensional dynamical system, principally based on the Lü system. The dynamic characteristics of this introduced system are evaluated and investigated by providing its 2D and 3D plots, time series for each state, discussing bifurcation scenarios and dissipation, the Poincaré map, and calculating its Kaplan–Yorke dimension. This system achieves hyper-chaos with two positive Lyapunov exponents. The generic stagnation points are computed, and their stability analysis is covered. The proposed system has also been studied via circuit implementation on Multisim. Towards the end of the manuscript, hybrid projective combination–combination synchronization among multiple drives and responses is attained through efficient adaptive control. Based on the principles of Lyapunov stability, several nonlinear controllers are created. All the acquired analytical results in the text are validated for their efficacy and viability through simulations on MATLAB. [ABSTRACT FROM AUTHOR]

Calculus in the urethra of the female is very unusual. The patient remains asymptomatic or uncommonly presents with symptoms of dysuria, post-void urinary dribbling, and dyspareunia. If asymptomatic, it can be diagnosed incidentally on gynecological examination. Being hard in consistency, it may mimic metastatic lesion. We present a case of a female who presented to us for management of ovarian mass. On routine examination there was a hard mass in her vagina which was suspected to be a metastatic lesion. This mass on evaluation came out to be a urethral diverticulum with a large calculus. Very large urethral calculus are a very rare presentation in a female. [ABSTRACT FROM AUTHOR]

In this paper, we have introduced a novel five-dimensional (5D) hyperchaotic system by extending the well-known Lorenz system. The dynamical properties of the system are analysed by calculating the Lyapunov exponents, graphing the phase portraits, bifurcation diagrams, the time series and by finding the Kaplan–Yorke dimension. The equilibrium points of the system have been calculated and the stability analysis of these equilibrium points is discussed. Hybrid function projective synchronisation has been carried out between the identical systems using the scheme of adaptive control. Suitable controllers have been designed to attain the desired synchronisation between the systems using Lyapunov stability theory. The theoretical results have been validated by performing numerical simulations using the MATLAB. [ABSTRACT FROM AUTHOR]

Smart transportation systems have been the focus of research due to the development of smart cities. However, existing vehicular networks are not sufficient enough to fulfill the vision of futuristic smart cities due to limited flexibility, scalability, poor connection, and insufficient intelligence. These technological hurdles make the role of Software-Defined Networking (SDN) very important to improve the overall performance of the existing vehicular networks considering the unique properties of SDN such as Decoupling of network planes and Real-time network programming. This leads to the development of Software-Defined Vehicular Networks (SDVNs). SDVNs help to realize the development of smart transportation systems which further helps to optimize the vision of truly smart cities. However, the security remains a consistent concern due to the increased mobility, larger attack surface, and improvised future attack vector. This work includes the different design components, and offers a detailed survey to understand different security issues including the architectural and functional ones. Additionally, multiple security solutions are discussed including Service-based, Infrastructure-based, and Application-based solutions. Furthermore, the work also covers the possible challenges in the development of SDVNs based on Improved Architectural Development, Holistic Integration, Effective Orchestration, Environmental Volatility Handling, Global Network Management, Efficient Components/Technologies Integration, Diverse Security Offerings, and Design Issues' Maintenance. Lastly, the work highlights the resultant opportunities based on Application, Open Research, Network Management, Device Configuration, Traffic Management, QoS, and Efficient Routing. [ABSTRACT FROM AUTHOR]

Key message: Heavy doses of gamma irradiation can reduce linkage drag by disrupting large sized alien translocations and promoting exchanges between crop and wild genomes. Resistance to mustard aphid (Lipaphis erysimi) infestation was significantly improved in Brassica juncea through B. juncea-B. fruticulosa introgression. However, linkage drag caused by introgressed chromatin fragments has so far prevented the deployment of this resistance source in commercial cultivars. We investigated the patterns of donor chromatin segment substitutions in the introgression lines (ILs) through genomic in situ hybridization (GISH) coupled with B. juncea chromosome-specific oligonucleotide probes. These allowed identification of large chromosome translocations from B. fruticulosa in the terminal regions of chromosomes A05, B02, B03 and B04 in three founder ILs (AD-64, 101 and 104). Only AD-101 carried an additional translocation at the sub-terminal to intercalary position in both homologues of chromosome A01. We validated these translocations with a reciprocal blast hit analysis using shotgun sequencing of three ILs and species-specific contigs/scaffolds (kb sized) from a de novo assembly of B. fruticulosa. Alien segment substitution on chromosome A05 could not be validated. Current studies also endeavoured to break linkage drag by exposing seeds to a heavy dose (200kR) of gamma radiation. Reduction in the size of introgressed chromatin fragments was observed in many M3 plants. There was a complete loss of the alien chromosome fragment in one instance. A few M3 plants with novel patterns of chromosome segment substitutions displayed improved agronomic performance coupled with resistance to mustard aphid. SNPs in such genomic spaces should aid the development of markers to track introgressed DNA and allow application in plant breeding. [ABSTRACT FROM AUTHOR]

Silver nanomaterials (AgNMs) ubiquitously known for their biological applications are studied here in terms of their shape-dependent antibacterial and anti-biofilm effect. Chemically synthesized nano-cubes (AgNCs) with size range around 150–200 nm were compared for their biological activity with commercial nano-sphere (AgNS) of comparable size (~160 nm). The antibacterial activity against both Escherichia coli and Staphylococcus aureus showed higher activity for nano-cubes compared with nano-spheres.The synergistic role of AgNMs with antibiotic ampicillin was also found promising. A four times enhancement and an increase of nearly 25% of antibiotic activity at 0.0625 mg ml–1 concentration was found with 0.05 mg ml–1 of AgNCs in agar and broth media, respectively. Anti-biofilm effect towards E. coli and S. aureus was also evaluated. AgNCs showed equal importance in biofilm disruption with 20% inhibition activity, which was yet again found better in-comparison with AgNSs. The study shows that AgNCs with distinct faces and edges could show efficient anti-bacterial effect and so such intelligently designed material could pave path for imminent medical challenges. [ABSTRACT FROM AUTHOR]