Stream processing platforms allow applications to analyse incoming data continuously. Several use cases exist that make use of these capabilities, ranging from monitoring of physical infrastructures to pre selecting video surveillance feeds for human inspection. It is difficult to predict how much computing resources are needed for these stream processing platforms, because the volume and velocity of input data may vary over time. The open source Apache Storm software provides a framework for developers to build processing applications that use the computing resources of all machines within an established cluster. Because of the varying processing needs of such applications, the platform should be able to automatically grow and shrink as needed. Unfortunately, the current Storm platform does not provide this capability. In this paper we describe the design and implementation of a tool that monitors several aspects of the Storm platform, the applications running on top of it, and external systems such as queues and databases. Based on this information, the tool decides whether extra servers are needed or machines may be decommissioned from the cluster, and then acts upon it by actually creating new virtual machines or shutting them down.

Pervasive systems, and domotics in particular, is an application area where heterogeneity is the norm, with thousands of autonomous heterogeneous devices live together and need to interoperate. One of the greatest difficulties in developing middleware for smart homes is that this kind of systems are extremely difficult to test and verify. We propose to reduce the testing costs by replacing actual home services with virtual stubs behaving as if they were actual hardware installed somewhere in the house and, most importantly, to visualize the behaviour of the home to give the user the impression and feedback of being in a real home.

No abstract

No abstract

Abstract-Cloud computing enables on-demand access to a shared pool of IT resources. In the case of Infrastructure as a Service (IaaS), the cloud user typically acquires Virtual Machines (VMs) from the provider. It is up to the user to decide at what time and for how long they want to use these VMs. Because of the pay-per-use nature of most clouds, there is a strong incentive to use as few resources as possible and release them quickly when they are no longer needed. Every step of the deployment process, i.e., acquiring VMs, creating network links, and installing, configuring and starting software components on them, should therefore be as fast as possible. The amount of time the deployment process takes can be influenced by the user by performing some steps in parallel or using timing knowledge of previous deployments. This paper presents four different strategies for deploying applications on cloud computing infrastructures. Performance measurements of application deployments on three public IaaS clouds are used to show the speed differences between these strategies.