Joanna Szmelter and Paul R. Williams
Evolution of designs is required to improve aerodynamic performance of projectiles. This paper examines current rapid prototyping techniques to determine if they can be used to manufacture wind tunnel models for aero-ballistics testing. Rapid prototyping (RP) and rapid manufacturing (RM) encompass technologies that are used to fabricate physical objects directly from computer-aided design (CAD) data sources [1] and aim to produce intricate and complex geometries relatively quickly, without the need for sophisticated machinery and tooling. A number of studies [2−7] have demonstrated the advantages of RP in terms of time and cost when developing wind tunnel models. Early studies of RP capabilities focused on polymer materials, many of which are unsuitable in highly stressed environments. In 1995 Agarwala et al. [8] stated that the ultimate aim of RP is to fabricate fully functional parts directly from metals and ceramics, and reported that selective laser sintering (SLS), technologies were capable of producing structurally sound metal parts for direct functional use. In practice, full-metal RP systems have only recently been commercialised for use outside of research environments, and application of RP parts in physically demanding environments is rare. Previous studies of RP techniques have concluded that RP was capable for lightly loaded wind tunnel models, but numerically controlled machining was best for parts enduring significant loads [2−3,9]. A recent progress in RP techniques motivates a new assessment.
Chris Janczura
This paper outlines an integrated framework in support of a generic problem of system of systems (SoS) integration and illustrates an application of the framework formalisms to evaluate a large architecture comprising the Air Combat Capability (ACC) integrated into its command control communication computer intelligence surveillance and reconnaissance (C4ISR) SoS environment. The framework utilises the notion of synthesis of executable architectures from their static Department of Defense Architecture Framework (DoDAF) specifications and focuses on the information interoperability aspect of integration. The DoDAF architecture, obtained in the earlier studies, was found not being readily amendable to development of executable models and hence certain refinements are performed. An operational activity process capturing the missions carried out by an ACC together with its corresponding properties is extracted from the architecture and modelled as coloured Petri net (CPN). State space analysis is utilised to investigate the CPN model. All possible execution sequences are generated and investigated to verify the properties of interest. The approach of developing executable architectures of the existing, large, non-execution compliant architectures assists analysts and designers to evaluate rigorously and efficiently and to compare architecture designs.
Meredith Hue
Insight is provided into architecture practice supporting development of deployed communications and information system (CIS) capability in the context of Network Centric Warfare (NCW). In determining what NCW capability may be extant in various instantiations of a force, and at different epochs, an important starting point is to understand what connectivity can be supported. An NCW intra-nodal technical reference model and a set of simplified architecture descriptions are outlined to support analysis of connectivity between disparate nodes in a heterogeneous networking environment. The approach to connectivity analysis is drawn from graph theory, which allows the force to be represented in simplistic terms as a set of graph nodes and links supporting different types of information transfer. This is then related to the actual NCW infrastructure which is carrying the respective information flows. The methodology supports analysis of what platforms and organisations share the same communication bearers, the same networking environments, and the same computer-based applications, including consideration of protocols employed, traffic types supported, gateways provided, security services supported, and how many users/system and systems/user. The methodology was used to support connectivity analysis during a recent major military exercise in support of measuring NCW capability of a Networked Maritime Task Group.
Panayotis K. Kikiras
IPAC (Integrated Platform for Autonomic Computing) aims at delivering a middleware and service creation environment for developing embedded, intelligent, collaborative, context-aware services in mobile nodes. IPAC relies on short range communications for the ad hoc realization of dialogs among collaborating nodes. Advanced sensing components leverage the context-awareness attributes of IPAC, thus rendering it capable of delivering highly innovative applications for mobile and pervasive computing. IPAC networking capabilities are based on rumour spreading techniques, a stateless and resilient approach, and information dissemination among embedded nodes. Spreading of information is subject to certain rules (such as space, time, and price). IPAC nodes may receive, store, assesses, and possibly relay the incoming content to other nodes. The same distribution channel is followed for the dissemination of new applications and application components that ‘join the IPAC world’.
M.S. Kemouche and Nabil Aouf
The problem of target tracking has been widely investigated in air surveillance systems. The hidden target state estimation is generally resolved in dynamic state space under assumptions of Gaussian noise and model linearity on motion and observation processes. A successful state estimation should be performed based on useful information extracted from motion observations, such as the target turn angle. In this paper, we present a generalised turn-prediction technique based on Hough transform to derive turn angle formed by two adjacent segments, and use this angle to predict target position. A H∞ filter is adapted to estimate and update turn angle after reception of a new measurement. The derived filter is combined with a straight motion filter in a hybrid scheme for manoeuvring target tracking. Simulation results have demonstrated the improvement of tracking performances with the proposed algorithm, without computation complexity growing.
Harris Sarfraz, Atif Bin Mansoor, Mark Richardson and Shahid Baqar
There are various costly aircraft IR signature-modelling software packages available in the marketplace that require high computational power. The goal of this paper is to present a cost-effective approach to these expensive options. In a low-fidelity model the whole aircraft body is taken as one IR source, while high-fidelity models aim at taking different parts of the aircraft as different IR sources. In our approach, the aircraft 3D model is divided into different parts such as nose, metallic body, glass canopy and exhaust gas plume and then the radiance of the different parts of the aircraft based on their emissivity and temperature is calculated to represent its high-fidelity IR signature. The model is validated against numerical values and visual thermal images of the aircraft. This personal computer based non-destructive application additionally provides a cost-effective alternative to the field trials/testing of flares in which numerous scenarios can be simulated efficiently and with controlled environmental conditions.
