Professor Cohen is one of the pioneers in computer simulation in astronomy. He is known for the ‘‘Ahmad-Cohen’’ method. This permits the simulation of stellar systems containing a large number of stars, such as galaxies and globular clusters.

Prof. Cohen’s major contribution to Quantum Mechanics and mathematical Physics has been the discovery of an infinite number of joint position momentum quasi-distributions. He also generalized the concept of Correspondence rules and Operator expansions. Associated with this development is the connection between correspondence rules and the Feynman path integrals. Although these distributions arose in Quantum Mechanics, they have found applications in many fields.

He is one of the main developers of the field called time-varying spectral analysis or time-frequency analysis. His method is routinely referred to as the ‘‘Cohen class" of distributions. To a very large extent he defined the field and has given us its basic methodology. The methods he developed, and those developed by other investigators based on his work, have given us new understanding of the fundamental nature of signals. These methods have been applied and have impacted many fields, including acoustics, machine vibration analysis, speech, biomedical signals, among others.