This paper approaches the process of validating and verifying the embedded control system of a satellite prototype. The focus of this approach is on the integration of UML and Petri nets, aiming at the formal verification of the system requirements. The approach is composed of: (1) simulation of the UML model in a CASE tool; (2) simulation of the Petri net model in a Petri net simulator; and (3...

Fractal antenna can meet the requirements of designing a multiband, low profile and small antenna. With advancement in wireless technology over the past decade, there is an increasing demand for miniaturization, cost effective, multiband and wideband antennas. Fractal antenna designs can support in meeting these requirements. Fractal antenna design is a geometric pattern that is repeated at eve...

We are developing software to simulate the behaviour of sea ice in a floe on the ocean surface, including interactions with solid objects (e.g., ships). In order to interact with this simulation and to visualize the results, we are developing a tool that gives the user the ability to set up the initial conditions, run the simulation, and display the simulated icefloe data in sequence. Initial d...

At-sea detection of marine debris presents a difficult problem, as the debris items are often relatively small and partially submerged. However, they may accumulate in water parcel boundaries or eddy lines. The application of models, satellite radar and multispectral data, and airborne remote sensing (particularly radar) to focus the search on eddies and convergence zones in the open ocean appe...

On April 6, 2009, an earthquake of 6.3 magnitude struck central Italy with its epicentre near L'Aquila, at 42.3502° N, 13.3762°E. The earthquake damaged 3,000 to 11,000 buildings in the medieval city of L'Aquila. Several buildings totally collapsed, 308 people were killed. The post emergency phase till now is just at its beginning step. Conventional surveying techniques using high precision tot...

This paper lays out requirements of disaster-tolerant and dependable networks and introduces the design of a network consisting of NerveNet[2,3] access points which create mesh-topological regional access networks with wireless and wired links, an unmanned aircraft wireless communication system, a satellite communication system, and sensors. We implemented a model of the network in a discrete e...

The paper describes the design, development, and characterization of a circularly polarized, wide beam radiating element for Electronically Steered Phased Array Antenna (ESPAA) for satellite communication (Satcom) on the move application at S-Band frequency. A corner truncated microstrip patch etched on Rogers TMM4 dielectric material placed on a rohacell filled the metallic cavity is proposed ...

This paper addresses the problem of modeling and simulating RF-signals captured by receivers of Global Navigation Satellite Systems (GNSS) in urban canyons. The presence of tall buildings in urban canyons often block lines of sight between receivers and GNSS satellites, and therefore signals reach the receivers indirectly, after bouncing off buildings. These multi-path and echo-only effects are...

With advancement in communication technology over the past decade, there is an increasing demand for miniaturization, cost effective, multiband and wideband antennas. Fractal antenna designs can support in meeting these requirements. Though these antennas provide several advantages but at the same time miniaturization and performance of the fractal antennas can be further enhanced using reconfi...

The Orbital Express Demonstration System (OEDS) flight test, flown from March to July 2007, achieved all of its mission objectives, demonstrating a suite of capabilities required to autonomously service satellites on-orbit. Demonstrations were performed at varying levels of autonomy, from operations with pause points where approval from ground was required to continue, to fully autonomous opera...