SDL based validation of a node monitoring protocol

Mobile ad hoc network is a wireless, self-configured, infrastructureless network of mobile nodes. The nodes are highly mobile, which makes the application running on them face network related problems like node failure, link failure, network level disconnection, scarcity of resources, buffer degradation, and intermittent disconnection etc. Node failure and Network fault are need to be monitored continuously by supervising the network status. Node monitoring protocol is crucial, so it is required to test the protocol exhaustively to verify and validate the functionality and accuracy of the designed protocol. This paper presents a validation model for Node Monitoring Protocol using Specification and Description Llanguage (SDL) using both Static Agent (SA) and Mobile Agent (MA). We have verified properties of the Node Monitoring Protocol (NMP) based on the global states with no exits, deadlock states or proper termination states using reachability graph. Message Sequence Chart (MSC) gives an intuitive understanding of the described system behavior with varying node density and complex behavior etc.Comment: 16 pages, 24 figures, International Conference of Networks, Communications, Wireless and Mobile 201

Disruption of Anatomy Dissection Practical in COVID-19 Pandemic: Challenges, Problems and Solutions

We are undergoing crisis for humanity with corona virus disease (COVID-19) causing extensive damage to life and its aspects. Moreover we do not know how this will unfold in near future. All the academic classes are suspended during nationwide lockdown to alleviate the propagation. It is high time to rethink ways to deliver quality medical education under restriction of social isolation and absenteeism in real time teachings and discussions. We propose, based upon our experiences, replacement of didactic gross anatomy dissection with handmade dissection videos and its implications. It has its own challenges which could be overcome with planned directives based upon current experience. What is the magnitude of the problem?In this gloomy environment of forced absenteeism, reluctance in study plans and procrastination requirescounseling for emphasizing the importance of tight declining schedule and benefits of timely curriculumfor covering huge syllabus. Traditional methods of face-to-face educational didactics, lectures and chalk talks has been compromised like no other time in past. Use of education technology at a mass scale for economically deprived countries, limited availability of techno friendly medical educators and adaptation of student to newer teaching techniques was already restrained in pre-pandemic time. Also, the alignment of new teaching format with amount of content and duration of topic coverage, necessary and safe enough to train for effective practice of problem-based learning warrants reorganizing available resources. From student’s perspective,accommodation and fooding concerns in lockdown, poor internet access with intermittent disconnection,lack of high-end laptops and absenteeism are major concerns, which precluded us from live streaming ofgross anatomy dissection. Also, it is to be ensured that changes in teaching style have positive impacton amount and depth of concerned knowledge

Study on Intermittent Faults and Electrical Continuity

connector, or incorrect installation during initial manufacture and assembly. Unless such issues are narrowed down to a specific root cause, any corrective actions or troubleshooting will be difficult to carry out, and hence its resolution may not make its way into future designs of the system. This leads to further susceptibility to NFF. Intermittent behaviour is often a clear sign of a partially damaged connector, or a connector undergoing a particular degradation mechanism, with the level of intermittency being further aggravated through process variation of harsh environments and parametric faults. In order to further our understanding of the relationship between degradation, operating conditions, intermittent behaviour within the subject, an experimental investigations have been carried out. This paper is a work in progress paper that illustrates a test regime that has been used to stimulate intermittence in electronic connectors whilst subjected to vibration, using both a traditional oscilloscope and bespoke intermittent fault detection equipment, in order to capture an intermittent signature. The results of these experiments provide an insight into the limitations of test equipment and requirements for future intermittent fault detection techniques

Over-The-Vacuum Update – Starlink’s Approach for Reliably Upgrading Software on Thousands of Satellites

Starlink operates the world\u27s largest constellation of over 4000 satellites, all of which receive regular software updates to deliver new capabilities, improve reliability and performance, and maintain security. Updating the software across the constellation requires solving two core challenges: safely updating an individual satellite in the harsh environment of space, and orchestrating thousands of updates without impacting users of the system. Variations on these problems have been addressed for large scale terrestrial compute systems by the broader software industry, and we have leveraged practices of that state of the art to develop a novel spacecraft software update system that delivers updates to the entire fleet of spacecraft on a rapid cadence. We developed a fault tolerant update system that is resilient to a breadth of failure classes, ensures consistency across a satellite composed of many independent computers, and is autonomous and self-correcting across a variety of traditionally challenging space operations scenarios. We leverage that system to adopt software industry standard practices like canary testing and progressive rollout. We have used this software update system to make over 200 updates to continuously deliver new functionality and improve performance of the fleet with no satellites lost due to failed software update

Long-term performance of a microbial electrolysis cell operated with periodic disconnection of power supply

This study describes a new approach for achieving stable long-term performance and maximizing the removal of chemical oxygen demand (COD) in a Microbial Electrolysis Cell (MEC). In the proposed approach, the MEC power supply is periodically disconnected, e.g. at a frequency of 0.1–0.5 Hz and a duty cycle of 90–95%. To evaluate the impact of such periodic power supply disconnection (on/off mode) on MEC performance, experiments were carried out in two flow-through MECs with activated granular carbon electrodes. The on/off operating strategy was applied to one MEC, while the other one was operated at a fixed voltage (control MEC). Long-term on/off operation resulted in progressive increase in COD removal efficiency (from 80% to 90%) and MEC current over time, while the control MEC showed stable but inferior performance. Furthermore, by changing the operating strategies and applying the on/off approach to the control MEC, its COD removal was increased from 78% to 83% and internal resistance decreased. The proposed on/off mode of operation can be used to develop a high-rate MEC-based wastewater treatment system

Research on Fault Analysis and Fault-Tolerant Control of EV/HEV Powertrain

International audienceThis paper presents research works in the topics of fault analysis and fault tolerant control of an electric vehicle powered by an inverter-fed induction motor drive and the usual sensors. The considered failures are mainly measurement error due to faulty sensors and power inverter malfunctions. When sensor failure occurs, both software and hardware redundancies have been investigated. Software redundancy has been evaluated in case of speed sensor failure. Hardware redundancy has been used in the case of power inverter failures with a fault-tolerant 4-leg topology. This topology exploits the induction motor neutral accessibility for fault-tolerant purposes. The proposed fault-tolerant approach brings a significant improvement compared to the phase-leg topology. This paper also presents the experimental validation of an efficient reconfiguration mechanism (transition strategy) at sensor fault occurrence

Tox and detox: Are teens\u27 smartphone use and non-use practices fully fungible?

The public sphere includes a range of credible discourses asserting that a proportion of teenagers (“teens”) has an unhealthy dependence upon continuous connection with media devices, and especially smartphones. A review of media discourse (Jaunzems et al.) in Australia, and a critical review of public discourse in Australia and Belgium (Zaman et al.), reveal both positive and negative commentary around screentime. Despite the “emotionally laden, opposing views” expressed in the media, there appears to be a groundswell of concern around young people’s dependence upon digital devices (Zaman et al. 120). Concerns about ‘addiction’ to and dependency on digital media first emerged with the Internet and have been continually represented as technology evolves. One recent example is the 2020 multi-part Massey Lecture series which hooked audiences with the provocative title: “we need to reclaim our lives from our phones” (Deibert). In Sydney, a psychology-based “outpatient addiction treatment centre” offers specialised recovery programs for “Internet addiction”, noting that addicts include school-aged teens, as well as adults (Cabin). Such discourse reflects well-established social anxieties around the disruptive impacts of new technologies upon society (Marvin), while focussing such concern disproportionately upon the lives, priorities, and activities of young people (Tsaliki and Chronaki)

Headlight Prefetching for Cooperative Media Streaming in Mobile Environments

Multimedia information services in mobile environments are becoming more and more important with the proliferation of technologies. Media streaming, in particular, is a promising technology for providing services such as news clips, live sports. To avoid service interruption when the users keep moving, proper data management strategies must be employed. We propose a new headlight prefetching technique for the streaming access points to deal with the uncertainty of client movement and the requirement of seamless service handoff. For each mobile client, we maintain a virtual fan shaped prefetching zone along the direction of movement similar to the headlight of a moving vehicle. The overlapping area and the accumulated virtual illuminance of the headlight zone on a particular cell determines the degree and volume of prefetching to be made by the streaming access point of that cell. Headlight prefetching solves the issues of identifying the streaming access points responsible for prefetching, the timing and the amount of data to prefetch in a single mechanism which is simple and effective. Simulation results demonstrate that our techniques can significantly decrease streaming disruptions, reduce bandwidth consumption, increase cache utilization and improve service response time