An evolvable, scalable, and resilient control channel for software defined wireless access networks

AbstractThis paper presents a novel multipath communication-based OpenFlow channel for Software Defined Wireless Access Networks (SDWANs), namely mOpenFlow. The advantageous features of mOpenFlow include the following: (i) resilience and scalability in wireless environments, (ii) evolvability of the existing access networks and the OpenFlow standard, (iii) a novel network calculus-based model for performance analysis of mOpenFlow. By leveraging the multipath communication for conveying OpenFlow traffic, mOpenFlow enhances both robustness (i.e., resilience) and throughput (i.e., scalability) of the control channel. To achieve the evolvability, mOpenFlow adopts the multipath transport control protocol, which conforms to SDWANs and the OpenFlow standard. We evaluate mOpenFlow in an emulated SDWAN in relation to the standard channel. The results show that mOpenFlow outperforms the standard channel, both in terms of robustness and scalability. Additionally, the numerical results indicate that the model provides a fast and reliable way for analyzing the end-to-end delay on mOpenFlow

The world-first deployment of narrowband IoT for rural hydrological monitoring in UNESCO biosphere environment

The success of a rural wireless monitoring system depends on establishing a reliable wireless link over the TCP/IP communication protocol in a challenging terrain and elevation profile. Several studies have shown that link reliability in a rural area can neither be predicted with high accuracy nor precisely modeled using existing mathematical channel modeling tools. Hence, the use of the empirical approach to infer wireless link reliability. This work focuses on the revival of a rural hydrological/water monitoring system with emphasis on the wireless link located in Tasik Chini, a lake with UNESCO biosphere status. The contributions of this study include: understudy the link reliability of a centralized wireless sensor network infrastructure system using the 2G and Long Range (LoRa) wireless network, the performance limitation of the low data wireless sensor network in a rural environment, approaches to revive rural water station monitoring center and finally highlight potential opportunities in rural wireless communications. View les

Impact of HBV Infection on Outcomes of Direct-Acting Antiviral Therapy of Chronic Hepatitis C

Background: Most clinical trials of direct-acting antiviral (DAA) therapy for hepatitis C virus (HCV) infection have excluded hepatitis B virus (HBV) coinfection, and little is known about the effects of DAA on chronic hepatitis C patients with HBV coinfection. Recent studies have reported that DAA therapy for HCV can also cause HBV reactivation in patients with HBV and HCV coinfection. The aim of this study was to assess the effects of DAA on sustained virologic response (SVR) and HBV reactivation in patients with chronic hepatitis C. Methods: Participants comprised 199 chronic hepatitis C patients who received DAA therapy (96 men, 103 women; mean age, 66.7 ± 12.0 years). Results: Twelve patients were coinfected with HCV and HBV. Sixty patients were HBV surface antigen negative but positive for hepatitis B core antibody and/or hepatitis B surface antibody, and one hundred and twenty-seven patients had not been exposed to HBV. Rates of SVR in HBV and HCV coinfected patients, HBV prior infection, and no exposure to HBV were 100, 95, and 97%, respectively. Significant differences were seen between each group. No case showed HBV reactivation. Conclusions: DAA treatments were effective in patients with HBV coinfection or HBV prior infection, as well as HCV monoinfection. As the number of cases was small, we still suggest caution regarding HBV reactivation in HCV and HBV coinfected patients undergoing treatment with DAA