Special issue on aspects of spatial and temporal signal processing

Conclusions This special issue focuses on aspects of current research in a topic of paramount interest that spans a wide area of applications and at the same time offers theoretically challenging problems. I wish to thank Professor Sydney R. Parker for inviting me to serve as the Guest Editor for what he considered would be an important and timely special issue. I hope that expectation is, at least, partly realized by the readers of this volume. For me, it was a rewarding experience to have interacted with the contributors and reviewers. I also value this opportunity to study many interesting results generated over the past several years. The help provided by the reviewers are gratefully acknowledged. I wish to thank the Air Force Office of Scientific Research and the National Science Foundation for their support of research, some of which has been referenced in this editorial.