Robert S. Matthews

Improving conformance and interoperability testing

m The increase in distributed applications and the need for information-sharing has led to increased demand for information-exchange standards to define the means by which applications can communicate. Although testing is critical to ensuring interoperable products, it does add time and cost to the development process. This article reviews work in progress on testing for the STEP standard that promises to reduce the cost of developing standards and standards-based products. An investigation of common approaches to test suite development and testing methods leads to some insights on ways to improve the overall process. Development time and cost can actually be reduced by better applying testing methods and tools. oday’s computer software applications are becoming increasingly distributed. Clientserver applications, distributed objectbased systems, World Wide Web applications, and agent systems all require applications that can exchange information. As applications become more distributed, the role of information-exchange standards, which are used to define a means by which two applications can share or exchange information, expands. The accelerating pace of technology change has dramatically increased the need for new standards and for changes in existing ones. It has also led to a demand for lower costs and a quicker delivery to market. Both of these trends place increased pressure on standards bodies to reduce the time and cost of development. A significant series of information-exchange standards, known as STEP (STandard for the Exchange of Product Model Data, officially ISO-10303 [STEP-1 1994]), is being explored and implemented by a number of major vendors. This standard is seen by many as the means by which several tiers of suppliers in various industries can electronically communicate product descriptions and their evolving changes over the product life-cycle. These descriptions may include mechanical, electrical, geometric, material, configuration, design, manufacturing, and analysis data. Early on, the National Institute of Standards and Technology (NIST), Navy ManTech, CALS, and key prospective users of STEP, who wanted to speed up the progress of STEP products to market, funded activities to develop better methods and tools for conformance and interoperability testing. These testing programs have been active for nearly five years and many of the desired results have been achieved. This article describes the relationship between conformance and interoperability testing, particularly in the context of STEP development. It has become clear during our work that the choice of test method depends greatly on where one is in the product/market life-cycle and on the means and objectives of the developing organizations. The following sections begin with a broader standard-independent perspective, and then, using examples from our current work ✮ F E A T U R E A R T I C L E

Swarming Unmanned Air and Ground Systems for Surveillance and Base Protection

The emergence of various risks to global security and stability is a motivation to develop remote sensing and monitoring systems that can be deployed on Unmanned Vehicles (UxVs). This requires the development of robust autonomous control technologies that can reliably coordinate large numbers of networked heterogeneous systems cooperating on a common mission objective. This paper describes a promising approach to addressing this challenge by using swarm intelligence to coordinate multiple heterogeneous vehicles and remote sensors in realistic applications. We describe a class of stigmergic algorithms based on digital pheromones to control and coordinate the actions of heterogeneous unmanned air and ground systems in two applications: broad area surveillance and base protection. An Operator System Interface was developed to evaluate techniques for enabling a single operator to monitor and manage multiple unmanned vehicles and unattended sensors of different types. The results from recent demonstrations of the technology using air and ground platforms are reported.

Effectiveness of Digital Pheromones Controlling Swarming Vehicles in Military Scenarios

The use of digital pheromones for controlling and coordinating swarms of unmanned vehicles has been studied under various conditions. This paper describes experiments that demonstrate their effectiveness in several militarily significant scenarios in simulation. The scenarios are described along with the results comparing the performance of swarming to traditional military tactics. A demonstration was conducted using these same algorithms to coordinate unmanned vehicles in a simulated exercise. Two air vehicles controlled by digital pheromones and four ground robots controlled by a related stigmergic algorithm successfully executed a two-hour multi-mission surveillance, patrol, target acquisition, and tracking scenario. The vehicles were given only high-level instructions, such as “survey this areaandidentifyandtrackanytargets”or“patrolaroundthisconvoy”.Theairvehicleswere abletodynamicallyadapttonewcommandsandcoordinatetheiractionswitheachotherand the ground robots to achieve the objectives. The algorithm’s robustness was demonstrated when it dynamically adjusted to the unplanned failure of one of the ground robots without any operator intervention.

Swarming methods for geospatial reasoning

Geospatial data are often used to predict or recommend movements of robots, people, or animals (‘walkers’). Analysis of such systems can be combinatorially explosive. Each decision that a walker makes generates a new set of possible future decisions, and the tree of possible futures grows exponentially. Complete enumeration of alternatives is out of the question. One approach that we have found promising is to instantiate a large population of simple computer agents that explore possible paths through the landscape. The aggregate behaviour of this swarm of agents estimates the likely behaviour of the real‐world system. This paper will discuss techniques that we have found useful in swarming geospatial reasoning, illustrate their behaviour in specific cases, compare them with existing techniques for path planning, and discuss the application of such systems.

Demonstration of Digital Pheromone Swarming Control of Multiple Unmanned Air Vehicles

The use of digital pheromones for controlling and coordinating swarms of unmanned vehicles has been studied under various conditions demonstrating their effectiveness in multiple military scenarios in simulation. An experiment was conducted to verify that these same algorithms could effectively coordinate unmanned vehicles in a simulated exercise. Two air vehicles (modified target drones) controlled by digital pheromones and four ground robots controlled by a related stigmergic algorithm successfully executed a two-hour multi-mission surveillance, patrol, target acquisition, and tracking scenario without any scripting. The vehicles were given only high-level instructions, such as “survey this area and identify and track any targets” or “patrol around this convoy”. The air vehicles were able to dynamically adapt to new commands and coordinate their actions with each other and the ground robots to achieve the objectives. The algorithm’s robustness was demonstrated when it dynamically adjusted to the unplanned failure of one of the ground robots without any operator intervention.