Institute of Education Sciences 
information elements 
Institute for European Studies 
Institute of Environmental Sciences 
Illuminating Engineering Society 
Imagery Exploitation System 
Imaging Electron Sensor 
Imaging Electron Spectrometer 
Industry Executive Subcommittee 
Information Exchange System 
Institute for Environment and Sustaina… 
Institute for Environmental Studies 
Integral Error Squared 
Intrinsic Electric Strength 
Inverted Echo Sounder 
Ion and Electron Sensor 
Industrial Electronics Society 
Information Exchange Service 
Institute for Earth Sciences 
Institute for Employment Studies 
Institute of Environmental Studies 
Institution of Engineers and Shipbuild… 
Institution of Engineers of Singapore 
Instituto de Estudios Superiores 
Integrated Engineering System 
Inter-Enterprise Systems 
internal eliminated sequence 
Internal Environmental Simulator 
International Exchange Service 
Illustrative Evaluation Scenario