scholarly journals A Feedback Approach for QoS-Enhanced MAC in Wireless Sensor Network

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Ang Gao ◽  
Yansu Hu
Keyword(s):  
Sensor Network ◽  
Linear Time ◽  
Wireless Multimedia ◽  
Differentiated Service ◽  
Linear Time Invariant ◽  
System Output ◽  
Linear Time Invariant System ◽  
Time Invariant ◽  
Lower Node ◽  
Qos Metrics

WSN as well as Wireless Multimedia Sensor Network (WMSN) has demands for QoS provision and differentiated service. The various types of data, such as video, voice, and network management, need to be periodically or best-effect transmitted. Since MAC layer forces the final physical medium accessing, it is the best choice to implement the QoS support for efficiency. This paper addresses the problem of QoS support in WSN from a renewed view of control theory and proposes FD-MAC architecture. By means of CSMA/CA, FD-MAC dynamically adjusts contention widow size according to the MAC frames’ priorities and their actual QoS metrics. The architecture can be modeled as a linear time-invariant system by system identification, and Least-Beat controller is designed to drive the system output to the desired value, which means the ratio of actual QoS metrics can be controlled to a prefixed value. The higher priorities enjoy a comparatively lower node-to-node delay while the lower priorities can still operate without being oversacrificed.

scholarly journals Zeros in linear systems with time delay in state

2009 ◽  
Vol 19 (4) ◽  
pp. 609-617 ◽  
Author(s):  
Jerzy Tokarzewski
Keyword(s):  
Time Delay ◽  
Linear Systems ◽  
Linear Time ◽  
Zero Dynamics ◽  
State Delay ◽  
Linear Time Invariant ◽  
System Output ◽  
Linear Time Invariant System ◽  
Time Invariant ◽  
Time Invariant System

Zeros in linear systems with time delay in stateThe concept of invariant zeros in a linear time-invariant system with state delay is considered. In the state-space framework, invariant zeros are treated as triples: complex number, nonzero state-zero direction, input-zero direction. Such a treatment is strictly related to the output-zeroing problem and in that spirit the zeros can be easily interpreted. The problem of zeroing the system output is discussed. For systems of uniform rank, the first nonzero Markov parameter comprises a certain amount of information concerning invariant zeros, output-zeroing inputs and zero dynamics. General formulas for output-zeroing inputs and zero dynamics are provided.

scholarly journals Temporal Variability in the Response of a Linear Time-Invariant Catchment System to a Non-Stationary Inflow Concentration Field

2020 ◽  
Vol 10 (15) ◽  
pp. 5356
Author(s):  
Ching-Min Chang ◽  
Kuo-Chen Ma ◽  
Mo-Hsiung Chuang
Keyword(s):  
Closed Form ◽  
Temporal Variability ◽  
Linear Time ◽  
Concentration Field ◽  
Surface Water Quality ◽  
Catchment Scale ◽  
Input Concentration ◽  
Linear Time Invariant ◽  
Linear Time Invariant System ◽  
Time Invariant

Predicting the effects of changes in dissolved input concentration on the variability of discharge concentration at the outlet of the catchment is essential to improve our ability to address the problem of surface water quality. The goal of this study is therefore dedicated to the stochastic quantification of temporal variability of concentration fields in outflow from a catchment system that exhibits linearity and time invariance. A convolution integral is used to determine the output of a linear time-invariant system from knowledge of the input and the transfer function. This work considers that the nonstationary input concentration time series of an inert solute to the catchment system can be characterized completely by the Langevin equation. The closed-form expressions for the variances of inflow and outflow concentrations at the catchment scale are derived using the Fourier–Stieltjes representation approach. The variance is viewed as an index of temporal variability. The closed-form expressions therefore allow to evaluate the impacts of the controlling parameters on the temporal variability of outflow concentration.

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