In the age of globalization and international collaboration, collaborative data sharing is crucial for computer-aided research. There is a growing demand for spontaneous, short-lived, and fine-grained collaboration acts that could be satisfied by a decentralized platform for the management of entities (users, groups, datasets). Our research is based on a pre-existing concept of such a decentralized platform, called the decentralized entity persistence layer (DEPL). We describe a novel architecture extending DEPL, called DEPL-DA, which introduces an idea of decentralized authority, allowing entities to be managed collectively by multiple organizations, at the same time ensuring fault tolerance and improving availability. Our proposal utilizes a synergy between consensus and atomic commitment protocols (AC&C) providing decentralization of authority over entities, at the same time providing means to perform atomic modifications of entities spanning across multiple authoritative domains. We propose two approaches to the integration of AC&C: competitive and cooperative, and implement them based on several existing AC&C protocols. The evaluation shows the differences between approaches and protocols used, as well as the fact that both approaches are viable and offer latencies acceptable by operations related to entity management.

In order to realize collaboration on a global scale, academic research requires often large quantities of data to be shared between geographically dispersed organizations.The requirement to protect and govern data in a network of loosely coupled, autonomous institutions is an incentive for decentralized solutions, where the participants are in full control of their data without trusting a third-party provider to store and process the data.In order to increase data availability and fault tolerance in decentralized collaborative systems, we propose a layer, which is based on replication and decentralized authority over the data.The solution consists of an idea of peer-sets, which are groups of peers implementing collective data management, a consensus protocol which synchronizes a distributed ledger between peers, and an atomic commitment protocol used to implement optional two-way references between documents.This architecture may be utilized in various decentralized collaborative data-sharing systems, such as Onedata.

The observation of current trends in data access, especially in the field of scientific computations, shows that global data access that crosses federation boundaries is highly desirable. However, administrative constraints require that data centers remain autonomous, which effectively eliminates the possibility of cooperation. To overcome this, we plan to establish an open network of cooperating data providers. In this paper, we address the issue of data access control for such network. Our proposition is to use a synergy of hybrid peer-to-peer architecture, decentralized identity and access management, metadata synchronization protocol and trust driven authorization flow. The proposed solution is discussed using real-life use-cases concerning cross-federation data access.

This paper describes the achievements of the H2020 project INDIGO-DataCloud. The project has provided e-infrastructures with tools, applications and cloud framework enhancements to manage the demanding requirements of scientific communities, either locally or through enhanced interfaces. The middleware developed allows to federate hybrid resources, to easily write, port and run scientific applications to the cloud. In particular, we have extended existing PaaS (Platform as a Service) solutions, allowing public and private e-infrastructures, including those provided by EGI, EUDAT, and Helix Nebula, to integrate their existing services and make them available through AAI services compliant with GEANT interfederation policies, thus guaranteeing transparency and trust in the provisioning of such services. Our middleware facilitates the execution of applications using containers on Cloud and Grid based infrastructures, as well as on HPC clusters. Our developments are freely downloadable as open source components, and are already being integrated into many scientific applications.

Using multiple Clouds as a single environment to conduct simulation-based virtual experiments at a large-scale is a challenging problem. This paper describes how this can be achieved with the Scalarm platform in the context of data farming. In particular, a use case with a private Cloud combined with public, commercial Clouds is studied. We discuss the current architecture and implementation of Scalarm in terms of supporting different infrastructures, and propose how it can be extended in order to attain a unification of different Clouds usage. We discuss different aspects of the Cloud usage unification including: scheduling virtual machines, authentication, and virtual machine state monitoring. An experimental evaluation of the presented solution is conducted with a genetic algorithm solving the well-known Travel Salesman Problem. The evaluation uses three different resource configurations: using only public Cloud, using only private Cloud, and using both public and private Clouds.

Big science needs synergistic approach from theory, experiment and computations. Significance of the computational science is still on its way up due to the importance of results concerning features of extreme time and space scales as well as of multiscale phenomena being a subject of current research. These needs have been recognized internationally and one of the activities undertaken in the last decade is the European Grid Infrastructure, consolidating national efforts on computational infrastructures developed under National Grid Initiatives (NGI). In the paper we present the way of building Polish NGI established for Polish scientists, allowing them to conduct interdisciplinary research on a national scale, and giving them transparent access to international grid resources via affiliated international grid infrastructures. The approach applied in setting up this e-infrastructure ensured integration with other similar platforms around the world, recently with special focus on domain specific solutions.