14-12-2012, 04:54 PM
Screen Spot: Multidimensional Resource Discovery for Distributed Applications in Smart Spaces
Screen Spot.pptx (Size: 178.29 KB / Downloads: 21)
ABSTRACT
The big challenge related to the contemporary research on ubiquitous and pervasive computing is that of seamless integration.
In this paper, we present middleware-level resource management service for situated displays in public smart spaces, acting as a scheduler and an arbiter for mobile clients.
We have implemented the discovery service and subjected it for alpha testing in an indoor setting. We report a proof-of-concept implementation of the Screen Spot system and we demonstrate an approach of visualizing the discovery results to the user.
INTRODUCTION
A typical usage scenario in this research field involves a mobile user with a smart phone, PDA or other similar networked terminal, utilizing services from the ambient surroundings.
STEPS
1) the user issues a discovery request including certain discrete keywords to the service repository.
2) which in turn performs static matchmaking to return a set of matching service descriptions from the directory.
Usage Scenario
These hotspots in conjunction with the personal mobile devices allow the deployment of distributed application structures that realize multimodal user interfaces towards the users.
Overview
The mobile terminals connect as pub/sub clients to the routing subsystem through the IEEE 802.11b panOulu WLAN access network.
Individual Resource Manager contain terminal computation entities that act as containers for the respective RM instances and interface the pub/sub routers through IEEE 802.3 Ethernet links.
In addition to the aforementioned connectivity, the mobile terminals also engage ad-hoc communications with the ambient RM instances through Bluetooth.
Through this short-range ad-hoc connectivity, we want to physically enforce the aspect of spatial proximity to the computation.
The Bluetooth coverage area forms an ad-hoc connectivity hot-spot around the situated display, and we utilize this coverage area as a virtual watchdog for monitoring the proximity between user and the display.
IEEE802.3 Ethernet
IEEE 802.3 is a working group and a collection of IEEE standards produced by the working group defining the physical layer and data link layer's media access control (MAC) of wired Ethernet.
This is generally a local area network technology with some wide area network applications.
Physical connections are made between nodes and/or infrastructure devices (hubs, switches, routers) by various types of copper or fiber cable.
Resource Manager
This instance resides within each situated display, and is responsible for the allocation and scheduling of the resource instance, as well as the execution of service instances residing on the resource.
This design reflects the tight coupling of the resource with the associated services, which is essential in the case of stateful distributed applications.
During the execution, it may be necessary to inject the application-related data from the client side to the respective ambient resource to reflect the state of the distributed application.
Policy Manager
Policy Manager acts as a container and controller for the usage policies set for this resource.
A single usage policy is an aggregation of resource utilization rules for a single user group.
These include an access control list with usernames of the group, the renewal policies allowed for the group, as well as the role that the group has in the smart space, i.e. employee vs. guest.
Fuego pub/sub client
Fuego pub/sub client realizes the networking interface towards the publish/subscribe routing system.
The subscription semantics utilized in the discovery service are hybrid in nature.
First, the routing system realizes a separate subscription channel for the discovery traffic.
Secondly, the RM instance on each ambient resource subscribes only to the messages targeted to this group of instances.
Service Proxy
Service Proxy acts as a singleton interface towards the core, and allows the execution of the service binaries residing within this resource object.
The service binaries are tightly coupled with the resource instance and the users issue utilization requests to the resource by setting leases to the associated lease queue.
Each lease must be associatively connected to a deployable service binary.
BT Server
BT Server implements the physical Bluetooth connectivity around the ambient hotspot.
This spatial connectivity has two distinct roles in our system.
First, users residing within the Bluetooth coverage area of a single hotspot can perform discovery requests to the rest of the system through the local hotspot.
Secondly, during the resource deployment, the Bluetooth coverage area acts as a virtual spatial watchdog.
Functionality
The main functionality of the system is to perform discovery requests within a physical smart space domain and return multidimensional resource information back to the user.
The attachment points for end users in the system are Bluetooth coverage areas around the ambient hotspots that provide resources and deployable services.