@conference {
	title = {Estimation of Random Signals based on Quantum Mechanical Measurements},
	author = {Baras, John S., Park, Young H.},
	year = {1974},
	month = {12/1974},
	abstract = {We consider here the problem of estimating a scalar random signal based on quantum mechanical measurements, a situation frequently appearing in optical communication systems. We find the minimum variance estimator based on the combination of optimal observable selection at each time and optimal linear processing of past measurements. We compare this estimator with the one obtained by optimal selection of observables at each time independently. Under additional assumptions we demonstrate that the former estimator uses the same physical devices as the latter, followed by recursive classical filtering. The results are illustrated in the estimation of the real amplitude of a random coherent signal through quantum mechanical measure-ments in a single mode cavity with background thermal noise.},
	address = {Pacific Grove, CA},
	booktitle = {8th Asilomar Conference on Circuits, Systems, and Computers},
	pages = {pp. 533-539}
}
@conference {
	title = {Recursive Filtering of Operator Valued Processes in Quantum Estimation},
	author = {Baras, John S., Harger, Robert O., Ephremides, Anthony.},
	year = {1974},
	month = {10/1974},
	abstract = {The unified approach to estimation of a stochastic signal satisfying a dynamical equation through the use of martingale and multiplicity theory is applied, in its infinite dimensional version, to the problem of estimation of a signal via quantum mechanical measurements in an optical communication system. The "state" is an operator valued stochastic process representing~a density operator in the quantum mechanical sense acting in an appropriate Hilbert space. The aim is the derivation of recursion relations for the optimum measurement operators that minimize a quadratic cost function. The Markovian nature of the density operator indexed by the signal process allows for optimum or suboptimum recursive filtering relations that are analogous to the ones in the classical case.},
	address = {Notre Dame, Indiana},
	booktitle = {1974 IEEE International Symposium on Information Theory}
}
@conference {
	title = {Lumped Distributed Network Synthesis and Infinite  Dimensional Realization Theory},
	author = {Baras, John S.},
	year = {1974},
	month = {04/1974},
	abstract = {We study the relations between infinite dimensional realization theory,~and the synthesis of networks using lumpted and distributed elements. In particular, we indicate how results from operator theory and especially the theory of invariant subspaces in HP spaces can be applied to both these problems. We discuss synthesis by reactance extraction and cascade synthesis.},
	address = {San Francisco, CA},
	booktitle = {IEEE Seventh International Symposium on Circuits and Systems},
	pages = {pp. 76-80}
}
@conference {
	title = {Natural Models for Infinite Dimensional Systems and their Structural Properties},
	author = {Baras, John S.},
	year = {1974},
	month = {03/1974},
	abstract = {We study here multi-input, multi-output distrib-uted parameter systems. The state space has the structure of a Hilbert space, and the evolution operators form a strongly continuous semigroup. We are thus able to include a large class of systems governed by linear partial differential equations. We present realizability conditions for the input-output maps considered and investigate canonical realizations and their properties. The main mathematical tools are invariant subspace theory in vectorial Hardy Spaces. Using the methods of this particular branch of operator theory we are able to classify the transfer functions considered according to their singularities. This classification is also related to system theoretic concepts and especially to the existence of spectrally minimal realizations. Finally, we discuss the implica-tions of these results to the structure theory of dis-tributed parameter systems, to lumped-distributed network synthesis and delay systems.},
	address = {Princeton, New Jersey},
	booktitle = {8th Annual Princeton Conference on Information Sciences and Systems},
	pages = {pp. 195-199}
}
