The Suburban Ad Hoc Network (SAHN) is a cooperative ad hoc wireless mesh network. Nodes are owned and operated by end-users without reliance on central infrastructure. It provides symmetrical bandwidth allowing peer-to-peer services and distributed servers. We minimize the use of scarce unlicensed RF spectrum supported by Smart Antenna technology. RF interference in such networks and techniques and strategies to reduce it are examined. Traffic is spread across multiple frequency channels, and multiple directional beams to achieve improved spatial re-use. We focus on the control of smart antennas rather than their design. By dynamically adjusting our network topology using Smart Antennas and dynamically re-routing current communications we optimize the network for its current traffic needs.

Wireless ad hoc networks are self-configurable distributed systems. One of the major problems in traditional wireless ad hoc networks is interference. The interference could be reduced using smart directional antennas. In this study, multibeam smart antennas have been used. When using this type of antenna, two nodes can communicate when both the sending and receiving beams are pointing towards each other. Also, a node can only communicate with a subset of nodes in its neighborhood depending on the number of beams and their beamwidth. Thus, the network topology needs to be dynamic in this case, andby controlling the topology network, performance can be increased. In this paper, we present a framework of a cross layer approach of topology control that interacts with the Routing layer and MAC layer and meets the required QoS of different data streams. The approach is fully distributed. When the network is initialized, the algorithm builds an initial connected topology and the routing algorithm uses this topology to find paths for the current communications. Then, depending on the network scenario, current communications and the required QoS, the topology control layer changes the topology to optimize the network performance. This study concerns Suburban Ad Hoc Networks (SAHN) where nodes tend to be fixed and are aware of their locations.

The Walnut kernel is a capability-based operating system kernel that was developed in the Department of Computer Science at Monash University during the 1990s. This kernel is heir to many of the ideas that were implemented in the PasswordCapability System. Focusing on the programmer’s view, this paper describes the password-capability model and the features of theWalnut kernel and the design decisions taken in creating it. An ANSI compliant standard I/O library is used as an example of the expressive power of the system.

Virtual reality systems are placing never before seen demands on computer graphics hardware, yet few graphics systems are designed specifically for virtural reality. An address recalculation pipeline is a graphics display controller specifically designed for use with head mounted virtual reality systems, it performs orientation viewport mapping after rendering which means the users head orientation does not need to be known accurately until less than a microsecond before the first pixel of an update frame is actually sent to the head mounted display device. As a result the user perceived latency to head rotations is minimal.