Wireless model-based predictive networked control system over cooperative wireless network

Owing to their distributed architecture, networked control systems (NCSs) are proven to be feasible in scenarios where a spatially distributed feedback control system is required. Traditionally, such NCSs operate over real-time wired networks. Recently, in order to achieve the utmost flexibility, scalability, ease of deployment, and maintainability, wireless networks such as IEEE 802.11 wireless local area networks (LANs) are being preferred over dedicated wired networks. However, conventional NCSs with event-triggered controllers and actuators cannot operate over such general purpose wireless networks since the stability of the system is compromised due to unbounded delays and unpredictable packet losses that are typical in the wireless medium. Approaching the wireless networked control problem from two perspectives, this work introduces a practical wireless NCS and an implementation of a cooperative medium access control protocol that work jointly to achieve decent control under severe impairments, such as unbounded delay, bursts of packet loss and ambient wireless traffic. The proposed system is evaluated on a dedicated test platform under numerous scenarios and significant performance gains are observed, making cooperative communications a strong candidate for improving the reliability of industrial wireless networks

Digital computer simulation of inductor-energy-storage dc-to-dc converters with closed-loop regulators

The simulation of converter-controller combinations by means of a flexible digital computer program which produces output to a graphic display is discussed. The procedure is an alternative to mathematical analysis of converter systems. The types of computer programming involved in the simulation are described. Schematic diagrams, state equations, and output equations are displayed for four basic forms of inductor-energy-storage dc to dc converters. Mathematical models are developed to show the relationship of the parameters

Max-min Fairness in 802.11 Mesh Networks

In this paper we build upon the recent observation that the 802.11 rate region is log-convex and, for the first time, characterise max-min fair rate allocations for a large class of 802.11 wireless mesh networks. By exploiting features of the 802.11e/n MAC, in particular TXOP packet bursting, we are able to use this characterisation to establish a straightforward, practically implementable approach for achieving max-min throughput fairness. We demonstrate that this approach can be readily extended to encompass time-based fairness in multi-rate 802.11 mesh networks

Protection and energy management of zero net electric energy clusters of buildings

This paper proposes the protection and energy management schemes for a smart dc micro-grid capable of 100% autonomous zero net energy in the cluster of buildings to facilitate a low-carbon sustainable electricity supply system. The proposed model comprises of house clusters with an autonomous communication developed for the residential area. Voltage droops and slope compensation peak current mode control techniques are employed for the bidirectional synchronous boost converter stages for energy storage systems (ESSs). The zone relaying device pertaining to dc protection is incorporated under set of rules related to current differential and overt current relaying schemes. The bidirectional converter stage for house clusters plays a pivotal role in stand-alone operation. In case a battery pack is laid off from any house cluster, the dc bus voltage still be stabilized due to the proximity bidirectional converter stages of other house clusters or community battery bank. The houses in the cluster comprise of permanent magnet synchronous generator (PMSG), solar photovoltaic (PV), battery bank and variable load. The proposed model is simulated on MATLAB/ Simulink environment and suffices the real time stochastic nature of wind, solar and load

Geological Investigations in Ellesmere Island, 1952

Contains an account of the author's studies of the Canyon Fjord region (ca. 80 N, 82 W), especially of Caledonian Bay, east of Eureka in summer of 1952. Studies of the Ellesmere Island mountains; and previous expeditions to Canyon Fjord are noted; the author's itinerary and his geological investigations are reported, proving the essential correctness of Lauge Koch's early contention that the mountains of North Greenland and Ellesmere Island are of the Caledonian age; author's collecting of plants and microfauna, observations on animals (muskox, hare, fox wolf, seals, birds) are mentioned. Bibliography (4 items)

Performance Evaluation of a Blockchain-based Content Distribution over Wireless Mesh Networks

This paper studies the performance of a proximity content distribution scheme over IEEE 802.11s mesh networks with reasonable user density among combinations of three network configurations and two transport mechanisms. For content access control, Hyperledger Sawtooth Blockchain with PoET (Proof of Elapsed Time) consensus algorithm is used as a decentralised storage of non-repudiated and rapid transactions for granting content access and distributing the content decryption key. An extensive performance evaluation of the content distribution and content access control protocols using ns-3 simulator was conducted. The results show that the integration of Blockchain and UDP multicast content distribution in a hybrid mesh network topology is highly feasible

Dynamic Strength of Titin's Z-Disk End

Titin is a giant filamentous protein traversing the half sarcomere of striated muscle with putative functions as diverse as providing structural template, generating elastic response, and sensing and relaying mechanical information. The Z-disk region of titin, which corresponds to the N-terminal end of the molecule, has been thought to be a hot spot for mechanosensing while also serving as anchorage for its sarcomeric attachment. Understanding the mechanics of titin's Z-disk region, particularly under the effect of binding proteins, is of great interest. Here we briefly review recent findings on the structure, molecular associations, and mechanics of titin's Z-disk region. In addition, we report experimental results on the dynamic strength of titin's Z1Z2 domains measured by nanomechanical manipulation of the chemical dimer of a recombinant protein fragment