Yanovska O. Models and method for services provision in a distributed cloud system

Object - systems based on cloud technologies and peer-to-peer networks; goal - to increase accessability of cloud services based on client-server and distributed cloud architectures; methods - methods of system analysis, set-theoretic methods and probabilistic description of information processes in computer networks, Markov processes theory with continuous-time and discrete states, methods for solving systems of differential equations with stiff coefficients, elements of information management process theory; results - developed models and method for resources provision in a distributed cloud system with required accessability level; novelty - a new method for services provision in a distributed cloud system that, in contrast to the current, is based on the use of distributed hash tables and passive data replication among the users' nodes; this allows to improve the efficiency of the response to a request by increasing the number of users; an enhanced Markov model for the availability of cloud service with client-server architecture based on the consideration of system state changes in various phases of virtual machines migration, and features of hardware and software virtualization; this improves the estimation accuracy of the probability that at any given time, the cloud service will be available to the end user with a predetermined response time; an enhanced Semi-Markov model for the availability of cloud service with distributed peer-to-peer architecture which takes into consideration the type and quantity of the resource part; this allows to define the requirements of fault tolerance and replication to ensure the required level of service availability; implementation - in the International airport “Kharkiv” NEW SYSTEMS AM Ltd., Center of Distance Education Technologies of KNURE, SE "Kharkiv research Institute of Manufacturing engineering'', DNN GROUP Ltd., NAU "KhAI"; field of application - cloud systems