Resumen Saffiotti

Alejandro Amat Bedmar

Summary of
“Seamless Integration of Robots and
Tiny Embedded Devices in a PEIS-Ecology”

The general purpose of this paper is to propose a middleware model which allows the seamless integration of standard robots and simple off-the-shelf embedded devices.
Their first statements are related with market tendencies that show the need of networked robotic devices in ourhomes and offices that can cooperate to perform possibly complex tasks. In order to cover this need the authors state that a wide sense robot concept is required. This robot concept has to include from very capable robots like humanoid ones to small and inexpensive networked devices which can be pervasively distributed in the environment.
The paper continues exposing the lack of a uniformmiddleware that allows the seamless integration of standard robots and (off-the-shelf or custom) tiny, resource-constrained embedded devices. Some references are mentioned at this point and PEIS-Kernel is proposed as a solution. PEIS-Kernel is the core of a PEIS-Ecology model implementation, which is intended to cover the lack of uniformity.

The key concept around PEIS-Ecology approach is said to becooperation, complex tasks are performed by the cooperation of many simple robotic components no by “high-tech” humanoid robots.
Three components are presented as essential:
1. A uniform notion of PEIS (Physically Embedded Intelligent System): any device incorporating some computational and communication resource and possibly able to interact with the environment through sensors and/oractuators.
2. A uniform communication model: which allows the exchange of information among the individual PEIS, and can cope with their dynamic joining and leaving the ecology.
3. A uniform cooperation model: each participating PEIS can use functionalities from other PEIS in the ecology in order to compensate or to complement its own.

From these components a PEIS-Ecology is defined as acollection of interconnected PEIS, all embedded in the same physical environment. A configuration of a PEIS-Ecology is a set of connections between components within and across the PEIS in the ecology.

In order to land all these concepts a reference implementation would be needed. That is what the authors present us in the next part of the article, their own open source implementation.PEIS-Ecology software stack have several layers:
1. An application layer on top. Includes support for navigation, planning, image processing, and some other tasks.
2. A middleware layer that includes features like introspection, planning, self-configuration, debugging, monitoring, etc.
3. A kernel which implements the PEIS abstraction discussed above, and which can be run on heterogeneoushardware and software environments.

A Linda-like tuple based approach augmented with an event mechanism is also proposed as communication model. This model allows PEIS to publish information as tuples and to search and consume relevant tuples produced by any other PEIS. Therefore a producer-consumer model is used for sharing capabilities between PEIS.
At lower level, the implementation of theshared tuple-space relies on a peer-to-peer network.

In more detail producer-consumer model works as follow:
* Each PEIS has its own namespace. Tuples produced by each PEIS (with its capabilities) are published with this namespace as prefix.
* When another PEIS modifies a tuple, this is first propagated to the owning PEIS-component, which is in charge of perform all temporal arbitrationof events and propagates copies of the value to all other interested PEIS-components.
* In order to be informed when a tuple has been modified a subscription mechanism is provided.

At this point we can say that PEIS-Ecology configuration concept presented before corresponds to a specific set of subscriptions. The way in which this configuration is inferred and deployed in a PEIS-Ecology...