  This paper deals with dynamic quantized consensus of dynamical agents in a
general form under packet losses induced by Denial-of-Service (DoS) attacks.
The communication channel has limited bandwidth and hence the transmitted
signals over the network are subject to quantization. To deal with agent's
output, an observer is implemented at each node. The state of the observer is
quantized by a finite-level quantizer and then transmitted over the network. To
solve the problem of quantizer overflow under malicious packet losses, a
zooming-in and out dynamic quantization mechanism is designed. By the new
quantized controller proposed in the paper, the zooming-out factor is lower
bounded by the spectral radius of the agent's dynamic matrix. A sufficient
condition of quantization range is provided under which the finite-level
quantizer is free of overflow. A sufficient condition of tolerable DoS attacks
for achieving consensus is also provided. At last, we study scalar dynamical
agents as a special case and further tighten the zooming-out factor to a value
smaller than the agent's dynamic parameter. Under such a zooming-out factor, it
is possible to recover the level of tolerable DoS attacks to that of
unquantized consensus, and the quantizer is free of overflow.
