ON DECENTRALIZED OBSERVATION AND DECENTRALIZED CONTROL OF LARGE SCALE SYSTEMS

In this paper, the problem of decentralized observation and decentralized control of linear, time-invariant large scale systems is studied. Based on conventional observer theory, the necessary and sufficient conditions for existence of completely decentralized observer are obtained. Moreover, the necessary and sufficient condition is given for stabilization of large scale systems by local output with state of the subsystem estimated through the completely decentralized observer.

Fundamental Issues in Networked Control Systems

Abstract--This paper provides a survey on modeling and theories of networked control systems （NCS）. In the first part, modeling of the different types of imperfections that affect NCS is discussed. These imperfections are quantization errors, packet dropouts, variable sampling/transmission intervals, vari- able transmission delays, and communication constraints. Then follows in the second part a presentation of several theories that have been applied for controlling networked systems. These theories include： input delay system approach, Markovian system approach, switched system approach, stochastic system approach, impulsive system approach, and predictive control approach. In the last part, some advanced issues in NCS including decentral- ized and distributed NCS, cloud control system, and co-design of NCS are reviewed. Index Terms--Decentralized networked control systems （NCS）, distributed networked control systems, network constraints, net- worked control system, quantization, time delays.

Water treatment and reclamation by implementing electrochemical systems with constructed wetlands

Seasonal or permanent water scarcity in off-grid communities can be alleviated by recycling water in decentralized wastewater treatment systems.Nature-based solutions,such as constructed wetlands(CWs),have become popular solutions for sanitation in remote locations.Although typical CWs can efficiently remove solids and organics to meet water reuse standards,polishing remains necessary for other parameters,such as pathogens,nutrients,and recalcitrant pollutants.Different CW designs and CWs coupled with electrochemical technologies have been proposed to improve treatment efficiency.Electrochemical systems(ECs)have been either implemented within the CW bed(ECin-CW)or as a stage in a sequential treatment(CW+EC).A large body of literature has focused on ECin-CW,and multiple scaled-up systems have recently been successfully implemented,primarily to remove recalcitrant organics.Conversely,only a few reports have explored the opportunity to polish CW effluents in a downstream electrochemical module for the electro-oxidation of micropollutants or electro-disinfection of pathogens to meet more stringent water reuse standards.This paper aims to critically review the opportunities,challenges,and future research directions of the different couplings of CW with EC as a decentralized technology for water treatment and recovery.