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Editor's Notes

• #3: This project is part of the UnBiquitous research group from the University of Brasilia
• #4: Our vision of ubicomp starts with the fact that presence of devices in everyday lives become more and more common as we speak
• #5: The task of ubicomp is to bring intelligence in such scenario in order for a better use of these devices.
• #6: But how can we bring intelligence to the environment? Who are responsible for this task?
• #7: Na the answer is the applications. But building applications in such a case can be very bothersome. Handling all the aspects individually is not a good idea.
• #8: So the most commom aproach in ubicomp environment is the use of middlewares. Ubicomp middlewares focuses on many challenges of building smart spaces. Among many of these initiatives we want to highlight three projects.
• #9: These projects were chosen given the fact that they address characteristics of the smart space that enhance the experience of the user. This characteristisc are
• #10: The different kind of interactions among devices and applicarions in the smart space. The capabilitie to handle the limitations of some devices, like CPU, memory and battery. And the wide variety of platforms available.
• #12: Since, among the sollutions found, none addressed the characteristics highlighted we’ve proposed this aproach. We’ve created a SOA based architecture in order to help organizing the smart space. A set of protocols for interfacing the communications in the smart space. And a middleware implementation for enabling this scenario.
• #13: The smart space is a set of two or more devices provided with computing power and interconnected by a communication network in a col laborative way.
• #14: A device is a computing equipment with communication capabilities, which must host applications or make resources available in the smart space.
• #15: RESOURCE: A resource is a group of functionalities logically related. These functionalities must be accessible in the environment through pre-defined inter- face. The concept of resource allows applications to be aware of a set of functionalities (services) in a more cohesive way. Resources can be either physical (like screen, keyboard, speaker, etc.) or logical (like user positioning, converters, etc.). Logical resources can provide new functionalities by accessing other resources. In SOA this is known as “composition”. A resource must be available to the smart space applications through a known public interface. In the DSOA a resource is uniquely identified by a name (or identifier ) and the set of services it provides.
• #16: (Resources, on the other hand, have their functionalities represented as services.) A service is the implementation of a functionality made available in the smart space through a resource with a known public interface. The service is responsible for providing the execution of functionalities of the resource. A service is only relevant if it’s capable of producing an effect that can be verified by other entities in the smart space. The interface of a service is defined by the resource the service is part of. A name (or identifier ) is responsible for uniquely identifying the service in a resource. The parameters that specify the information required for the execution of the service are also part of its interface.
• #17: The DSOA assumes two capabilities in order for its organizations to work. Firstly, the smart space must be able to aswer queries of which resources are available. And secondly, the resources must be able to answer to service calls.. That’s where the uP comes into scene.
• #19: We’ve chosen as message format for the uP the JSON format for its characteristics of being structured, multi-platform and lightweight. The first two characteriscts are common ground with the XML format but the later our testes shows that JSON takes a good advantage.
• #20: According to what we’ve seen, JSON shows less use of CPU and memory. Not to mention bandwidth which lead to its use in many web services nowadays.
• #21: Using json we not only represent our messages but also the concepts of DSOA like resources, represented as drivers and services.
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