The three-volume set LNCS 12181, 12182, and 12183 constitutes the refereed proceedings of the Human Computer Interaction thematic area of the 22nd International Conference on Human-Computer Interaction, HCII 2020, which took place in Copenhagen, Denmark, in July 2020.* A total of 1439 papers and 238 posters have been accepted for publication in the HCII 2020 proceedings from a total of 6326 submissions. The 145 papers included in these HCI 2020 proceedings were organized in topical sections as follows: Part I: design theory, methods and practice in HCI; understanding users; usability, user experience and quality; and images, visualization and aesthetics in HCI. Part II: gesture-based interaction; speech, voice, conversation and emotions; multimodal interaction; and human robot interaction. Part III: HCI for well-being and Eudaimonia; learning, culture and creativity; human values, ethics, transparency and trust; and HCI in complex environments. *The conference was held virtually due to the COVID-19 pandemic.

The book presents principles of operation of radar and radionavigation systems. The group of radar systems includes: primary and secondary radiolocations, bistatic and multistatic systems. They are illustrated with relevant examples of calculation and applications. The issues of increasing the range of the radar systems are presented together with the matched filtering of the used signals. Other discussed issues are methods for eliminating interfering signals and researching methods of 3D space. Various methods of the monopulse radiolocation are presented in Chapter 12. In Chapters 13–18 terrestrial and satellite radionavigation systems are under discussion. The terrestrial systems are: Loran C, Decca Navigator and Omega. The TRANSIT is an example of a hyperbolic satellite system. The stadiometric systems GPS, GLONASS, GALILEO, BeiDou, IRNSS and QZSS are discussed together with differential systems augmentating of them. The ILS, MLS and TLS supporting the landing of aircrafts are discussed in Chapter 17. The prospects for replacing of them with satellite systems augmentated by appropriate reference ground-based stations (GBAS) are also analyzed. Various beacons and ranging devices used in aviation are described in the Chapter 18. This book is intended primarily for students and engineers interested in radar, radionavigation and aerospace engineering.

February issue includes Appendix entitled Directory of United States Government periodicals and subscription publications; September issue includes List of depository libraries; June and December issues include semiannual index