## WSN-DPCM Architecture and Design Flow  
The WSN-DPCM toolset flow was designed to reduce the application development and deployment effort and the time-to-market for new WSN applications. It enables software-assisted engineering and provides most of its integrated capabilities as services over the Internet. Its operation flow is correlated with the DPCM data model, which holds all information items used by the different tools of the Platform as input/output, from the creation of a new Project to online monitoring of the designed WSN network in a real-life environment. Model entities can be created, modified or deleted throughout a toolset session. The hierarchy of the model is shown in Figure 2. It comprises the following main entity types:  
* PROJECT--project description and attributes. It includes references to the USER and the list of PLAN entities defined for the Project. * PLAN--deployment plan definition and attributes. It includes references to SIM entities as a result of the simulations executed over the plan specification, the CONNECTIVITY matrix entity as attachment and all references to the definition entities of the node types considered by a particular deployment. * USER--contact information and credentials of the project's user. * CONNECTIVITY MATRX--structured file in JSON format that contains the communication properties and transmission values estimated by the simulation of the radio links between each pair of nodes. * NIDDEF--type definition entity for network interface devices (NID, e.g., gateways). It contains all details that characterize a NID type structurally (type identifier, nature, functional blocks, parameters _etc._) and functionally (properties, configuration choices, _etc._). This specification is correlated with the embedded code generated for this particular type of node. * ROOTDEF--type definition entity for sink node devices, similar to the NIDDEF entity. It can contain node programming software when the code synthesis phase is completed. * NODDEF--type definition entity for regular leaf node devices, similar to the NIDDEF and ROOTDEF entities. It can contain node programming software when the code synthesis phase is completed. * SIM--RF simulation entity that contain its configuration attributes and results for the targeted nodes. The platform is based on three main tools, the Planning Tool, the Development Tool and the Commissioning & Maintenance Tool, and supporting components, Library of components and the Middleware, each consisting of integrated services that are accessible through a local/web GUI (WebTop Environment) and/or RESTful services (Figure 3). The WebTop Environment is a web desktop application that requires no local installation and acts as a unique entry point to the toolset through user authentication. It provides the main user interface to the WSN-DPCM toolset, all visualization support needed by its tools and other information, as well as the controls needed to advance through the development flow. As shown in Figure 3, it has control interfaces with each of the main platform tools in order to control their execution (e.g., start, stop, status) and data interfaces with the Project Repository of the platform in order to check the advance status of the various development stages, as reported by the tools. The Planning Tool (PT) provides the developer with a graphical input interface for the deployment field map, for the definition of WSN node types and their positions in the field, and for other platform tools that need to analyze various aspects of node deployment (e.g., RF propagation, signal strength and coverage strength, optimal topology and connectivity). It has a control interface with the WebTop Environment and a data interface with the Project Repository of the platform to save new projects or retrieve older ones. Figure 3: Overview of the WSN-DPCM Toolset communication and typical development flow. Figure 2: Diagram of the data model hierarchy and the multiplicities among its entities.