Development of Science Gateways Using QCG -- Lessons Learned from the Deployment on Large Scale Distributed and HPC Infrastructures

Today, various Science Gateways created in close collaboration with scientific communities provide access to remote and distributed HPC, Grid and Cloud computing resources and large-scale storage facilities. However, as we have observed there are still many entry barriers for new users and various limitations for active scientists. In this paper we present our latest achievements and software solutions that significantly simplify the use of large scale and distributed computing. We describe several Science Gateways that have been successfully created with the help of our application tools and the QCG (Quality in Cloud and Grid) middleware, in particular Vine Toolkit, QCG-Portal and QCG-Now, and make the use of HPC, Grid and Cloud more straightforward and transparent. Additionally, we share the best practices and lessons learned after creating jointly with user communities many domain-specific Science Gateways, e.g. dedicated for physicists, medical scientists, chemists, engineers and external communities performing multi-scale simulations. As our deployed software solutions have reached recently a critical mass of active users in the PLGrid e-infrastructure in Poland, we also discuss in this paper how changing technologies, visual design and user experience could impact the way we should re-design Science Getaways or even develop new attractive tools, e.g. desktop or mobile-based applications in the future. Finally, we present information and statistics regarding the behaviour of users to help readers understand how new capabilities and functionalities may influence the growth of user interest in Science Gateways and HPC technologies.