Modularized middleware architecture for smart home & smart home lab Software Engineering Laboratory Department of Computer Science Iowa State University

Design goals Reconfigurability –Service coordinator (Service composer) A new description language or a extended version of BPEL4WS –Service execution engine Scalability –Fully modularized/Impendent layers operating system independent Application interchangeability by supporting Uniform APIs –Easy to add/remove new services Component-based services to support “plug-and-play” Modularity –Boundary between the layers for the smart home and the ones for the smart home lab Our architecture includes the features that are required for experiments and help write lab-only-used applications Two Java-based frameworks –Minimize overhead at the deployment phase

Design characteristics Service –All the services of the smart home are context-aware. Thus, service design also includes context analysis. –Two levels of services to be associated Context-based service (high-level) –The service delivered to a customer based on their necessity or preference Device-specific service (low-level) –The description of basic functionalities of a device such as sensors or controllers Layered Middleware architecture –Clear interface definitions between the layers EJB-based component support –Java can work with (or over) OSGi –JavaME is available for small devices –Easy to interact with other services by extending smart home services to web services

Middleware architecture overview Physical Device normalization/Integration Service support Security Safety Application Web-based interface Dev/Exp support Design module Design module Case- Based module Case- Based module Service Execution module Service Execution module Context analysis module Availability Audit module Audit module Service DB (SDB) Service DB (SDB) Knowledge DB (KDB) Knowledge DB (KDB)

Middleware architecture layers (1/4) Physical –Consist of a variety of devices and appliances such as cell phones, PCs, PDAs, sensors, detectors, controllers (for example, X10), etc. Device normalization/Integration –Wrap any devices and appliances of the physical layer in a software service to construct device-specific services Register them with service framework interfaces (SFIs) –Java-based integration environment for services Communication management, Message processing, etc. Shared databases –Knowledge database (KDB) for context-awareness –Service database (SDB) for service publication and discovery

Middleware architecture layers (2/4) Service support –Context analysis module Reason a situation based on diverse context through the KDB Associate a context with a service in order to construct context-based services Types of context –Static context: Bar code, RFID tag, … –Dynamic context: the data of sensors/controllers –Service execution module Binding a service with real software –Question: Need dynamic service composition?  Inference engine Invoke services though the SDB –Implicitly based on the context analysis –Explicitly by the occupant

Middleware architecture layers (3/4) Development/Experiment support –Design module Register/Publish an service Manage the SDB Describe using a standard service description language such as WSDL –Case-based module Define an association of a context with services Manage the KDB Describe using a new language or an extended version of BPEL4WS –Audit module Logging/Extracting data and status information –Publish exceptional conditions Interact with the SDB and the KDB

Middleware architecture layers (4/4) Application –Manage/Scheduling independent programs to monitor/control services –Examples Context descriptor Audit analyzer Service composer Service simulator Service administrator Web-based Interface –Optional to offer a consistent interface to occupants –Provide ubiquitous accessibility by making applications web-accessible Support remote access via both wired and wireless internet

Requirements for smart home lab (1/3) The key requirements for the smart home lab 1.SHL/SH shall have wireless/wire network 2.SH shall be operated normally when the middleware architecture is abnormal 3.SHL/SH shall have the security mechanism 4.SH shall have the ability to detect occupants’ context and identification if there are more than one occupant 5.Middleware Architecture 1)The middleware architecture shall accept inputs/commands from i.Cell phones ii.PCs iii.PDAs iv.Sensors v.detectors vi.Controllers (such as X10) 2)The middleware architecture shall have the ability to communicate with other organizations

Requirements for smart home lab (2/3) The key requirements for the smart home lab (cont) 5.Middleware Architecture (cont) 3)The middleware architecture shall give commands/outputs to i.Cell phones ii.PCs iii.PDAs iv.Devices v.Other organizations 4)The middleware architecture shall store data such that it can be imported/exported in some specific formats (efficiently) 5)The middleware architecture shall be able to discover plug-in devices 6)The middleware architecture shall have the ability to integrate appliances/devices 7)The middleware architecture shall automatically turn on/off some appliances/devices if some specific events occur 8)The middleware architecture shall be able to change its behavior for time- and situation-awareness 9)The middleware architecture shall be able to remind the occupants for some specific things

Requirements for smart home lab (3/3) The key requirements for the smart home lab (cont) 6.Device Control 1)Researchers shall be able to enable/disable devices 2)Researchers shall be able to view/retrieve the status of a device 3)Researchers shall be able to operate all the functions of a device 7.Experiment Simulation Capability 1)Researchers shall be able to create the services/simulations/experiments over the middleware architecture 2)Researchers shall be able to extract system status information 3)Researchers shall be able to develop their new applications

Device Normalization/Integration OSGi (Open Services Gateway Initiative) EJB (Enterprise Java Beans) B/S/ H/ Resi denti al Gate way Tablet PC Mobile telephone WLAN GSM Powerline Indoor Communication Outdoor Communication

Why EJB/OSGi? (1) To support component-based software architecture –Modular Components (EJB/OSGi) –Reusability (EJB/OSGi) –Collaborative Model (OSGi) –Highly Dynamic (OSGi) –Software Lifecycle Management (OSGi) EJB –Visual assembly of applications OSGi –Open industry framework and service-oriented architecture –Deployment of services in platforms

Why EJB/OSGi? (2) Advantages of OSGI –OSGi defines a framework to mange bundles (units of distribution) and the services they export –Services can be obtained by querying the framework through a set of properties Disadvantage of OSGi (cons of EJB) –Assemblies are not static. Connections between bundles occur depending on the availability of services Solutions [Cevantes02] –Use bundles as distribution units that contain JavaBeans –Make these bundles export some particular services that allows for the creation of instances of the JavaBeans they export –Give JavaBeans access to the OSGi framework, so that they can quey for services in a complete way [Cevantes02] H. Cervantes and J. Favre, “Comparing JavaBeans and OSGi Towards an Integration of Two Complementary Component Models”, Euromicro Conference, 2002.