Ramiro Liscano

Using a blackboard to integrate multiple activities and achieve strategic reasoning for mobile-robot navigation

We have designed a mobile robot system architecture that uses a blackboard to coordinate and integrate several real time activities. An activity is an organizational unit, or module, designed to perform a specific function, such as traversing a hallway, going down steps, crossing over an open channel on the floor, or tracking a landmark. An activity resembles a behavior in that it controls the robot to perform a specific task. It differs from a behavior in that it is designed to perform the specific task in a narrow application domain, whereas a behavior generally resembles a biological response-that is, an organisms response to a stimulus. The activity based blackboard system consists of two hierarchical layers for strategic and reactive reasoning: a blackboard database to keep track of the state of the world and a set of activities to perform real time navigation. >

A system architecture for a mobile robot based on activities and a blackboard control unit

The design and implementation of a system architecture for control of a mobile robot is presented based on the notion of activities that are supervised by a blackboard system. An activity is defined as an organizational unit which exhibits a basic skill. Six behavior and five design requirements are defined and are used in evaluating the performance of the system architecture. It is the authors contention that if a mobile robot is to function autonomously in an unknown environment, it must meet these requirements. Using these requirements the activity-based architecture presented can be compared to other existing systems. Actual implementations of two activities (a passageway and channel activity) are used to validate the performance of this architecture.<<ETX>>

A Comparison of Real-Time Obstacle Avoidance Methods for Mobile Robots

Recently several new dynamic approaches have been developed to enable a vehicle to autonomously avoid obstacles in its environment in real time. These algorithms are generally considered as reflexive collision avoidance algorithms since they are continuously using the latest update in sensory data and computing from this data error signals to drive and/or steer the vehicle away from a collision with the environment. This paper experimentally tested three of these methods, potential fields, generalized potential fields and vector field histograms, using a uniform set of hardware and software modules. The types of tests chosen were typical of navigation in an indoor environment and consisted of avoiding a single obstacle at high speed, travelling through a narrow hallway and passing through an open doorway. The main issues observed during the testing were, the maximum speed at which the vehicle could accomplish the test, the nature of the path taken by the vehicle during the test and any difficulties that arose in the process of implementing any of the algorithms.

A common multi-agent testbed for diverse seamless personal information networking applications

This article describes the design and implementation of a unique cooperative agents testbed aimed at addressing diverse applications for the difficult problem of seamless personal information networking (SPIN). The real-world SPIN testbed is aimed at two difficult applications. Namely seamless messaging and intelligent network management. Both applications are agent-driven and share agent behavior, and the messaging agents rely on the network management device diagnostic agents for input. The article introduces both problem areas in a common testbed. The first-generation seamless messaging application is described in detail. User-centric seamless messaging assumes heterogeneous communication environments intended to support todays nomadic users. The prototype is introduced for the management of messages across distributed information networks. Its aim is to intercept, filter, interpret, and deliver multimodal messages, be they voice, fax, video, and/or e-mail messages. A users personal communication agent is charged with delivering messages to the recipient regardless of their target messaging device-a telephone, pager, desktop, wireless laptop, or wireless phone. Personal communication agents classify and act on incoming messages based on their content. A secretary agent routes and tailors urgent messages appropriately to the device manager agent, which delivers the message to a device on which the user may be roaming or active. What makes the seamless messaging application unique is its approach to treating a message in a universal manner, and its ability to mediate between different messaging environments and devices, and to try to track and find the user.

Active range sensing for indoor environment modeling

This paper investigates modeling indoor environments using a low-cost, compact, active-range camera, known as BIRIS, mounted onto a pan and tilt motor unit. The BIRIS sensor, developed at the National Research Council of Canada, is a rugged small camera with no moving parts. The objectives of this paper are to describe and demonstrate the viability of the use of a low-cost range sensor in the domain of indoor environment modeling; to present the results of processing three-dimensional (3-D) data to build a virtual environment for navigation and visualization; and, to analyze and outline the advantages and limitations encountered when scanning large indoor environments.

Indoor Ad Hoc Proximity-Location Sensing for Service Provider Selection

There are protocols that can be used by mobile clients to discover service providers in foreign networks to which they get attached, e.g., SDP of Bluetooth and SLP of IETF. These protocols do address service discovery, but do not address the selection of a service provider among a set of candidates according to a physical proximity of the client and service provider. The goal of the research described in this paper is to integrate proximity-based selection mechanisms to service discovery protocols. We present in this paper protocols that allow nomadic clients to discover and select service providers according to physical proximity.

A multi-agent system for personal messaging

Permission is granted to quote short excerpts and to reproduce figures and tables from this report, provided that the source of such material is fully acknowledged.

3D data acquisition for indoor environment modeling using a compact active range sensor

This paper investigates modeling indoor environments using a low-cost compact active range camera, known as BIRIS, mounted onto a pan and tilt motor unit. The BIRIS sensor, developed at the National Research Council of Canada, is a rugged small camera with no moving parts. The contributions of this paper are mainly in three areas: it demonstrates the viability of the use of a low-cost range sensor in the domain of indoor environment modeling; it presents the of processing 3-D data to build a virtual environment for navigation and visualization; and, it analyses and outlines the advantages and and limitations encountered when scanning large indoor environments.

Dynamic Role Assignment Using Semantic Contexts

Contextual information plays an important role in hiding technological complexities from a users point of view in ubiquitous and pervasive environments. In terms of access control, contextual information can be used to minimize the set up and access control complexities and at the same time to allow users to gain access to resources pervasively without difficulties. RBAC has been used and adopted widely in facilitating an access control mechanism. A variation of RBAC is dynamic role assignment in which users are assigned roles based on their situations. This paper uses semantic contexts in order to determine appropriate roles assignment for an incident management system.

A Common Multi-agent Testbed for Diverse Seamless Personal Information Networking Applications

The paper describes the design and implementation of a unique cooperative agents testbed intended for diverse applications in seamless personal information networking. The real-world SPINTM1 testbed is aimed at two applications, namely seamless messaging and intelligent network management. Both are agent-driven and share agent behaviours. The messaging agents rely on the network management device diagnostic agents for input. The first generation of Seamless MessagingTM is described in detail. It is user-centric and assumes heterogeneous communication environments intended to support todays nomadic users. A prototype is introduced for the management of messages across distributed information networks. Its aim is to intercept, filter, interpret, and deliver multi-modal messages be they voice, fax, video and/or e-mail messages. A users Personal Communication AgentTM (PCA) is charged with delivering messages to the recipient regardless of their target messaging device be it a telephone, a pager, a desktop, a wireless laptop or a wireless phone. PCAs classify and act on incoming messages based on their content. A Secretary AgentTM routes and tailors urgent messages appropriately to the Device Manager AgentTM which delivers the message to a device that the user may be roaming or active on. What makes Seamless Messaging unique is its approach to treating a message in a universal manner, its ability to mediate between different messaging environments and devices, and its capability of tracking and finding users.