DSTO Scientific Publications

A Study of Condition Based Maintenance for Land Force Vehicles.

Report Number: DSTO-GD-0664
Author: Rajesh, S.; Francis, B.
Issue Date: 2012-03
AR Number: AR-015-194
Classification: Unclassified
Report Type: General Document
Division: Land Operations Division (LOD)
Release Authority: Chief, Land Operations Division

Abstract

Condition Based Maintenance (CBM) is a method of both diagnostic and prognostic maintenance that has been used extensively in the air environment. This report describes a literature review of CBM where it relates to the land-based platform maintenance in particular. The review outlines the current state of CBM analysis, and in particular in terms of prognostic fleet management. Emphasis is further placed on an enquiry into the costs and benefits of CBM for land force equipment maintenance. A number of CBM cost-benefit studies are used as case studies to provide a framework for future analysis, including the potential challenges and the issues that CBM could bring to Army if implemented. The insights gained from this review give an understanding of the introduction and implementation of CBM to legacy fleets, but in particular the adoption of CBM into new equipment fleets such as LAND 400.

Executive Summary

There has been a drive over recent years to incorporate the concepts of condition monitoring which have been developed in the air environment into the domain of land-based platform maintenance. Under this paradigm maintenance transition from a time-based construct to one based on the need, or condition, of the platform itself. This Condition Based Maintenance (CBM) remains relatively new within the context of legacy military land vehicles within the Australian Army, yet it is likely to become more prevalent with future platform acquisitions, such as LAND 121 and LAND 400 in particular.; This report presents a literature review of CBM, with emphasis placed on the issues relating to land platforms. An important component of this review is an attempt to articulate what is understood in terms of a CBM system, and to provide a working definition for discussion. Another central theme of this review is to inform debate on developing a value proposition for CBM being introduced into Army, and in new fleets in particular. An important component of this is to understand the cost-benefit analysis that has been done to date and identify relevant factors for any future work conducted by Land Operations Division.; Whilst the literature review found technical papers focusing on the capacity to sense equipment condition, there were fewer dealing directly with the health prediction of specific sub-systems. There is less published on the success or otherwise of actual systems applied to land vehicles. Indeed, the predominant focus has been the technology aspects of the sensors themselves. There has been less analysis on the broader requirements of CBM beyond the platform, or indeed how CBM might inform decisions at different levels within Defence, or how it might be used to prime the spares supply chain. The report outlines at least some of the likely costs and benefits and furthermore discusses some of the potential challenges to be faced during the introduction of any CBM system into Army land-based platforms.

A Pseudo-Reversing Theorem for Rotation and its Application to Orientation Theory.

Report Number: DSTO-TR-2675
Author: Koks, D.
Issue Date: 2012-03
AR Number: AR-015-246
Classification: Unclassified
Report Type: Technical Report
Division: Electronic Warfare & Radar Division (EWRD)
Release Authority: Chief, Electronic Warfare & Radar Division

Abstract

We state and prove a useful theorem on manipulating rotation order which, while not new, is barely present in the literature. This theorem allows the order of a sequence of rotations to be reversed, provided that the sense of the axes of rotation is changed from â��bodyâ�� to â��space fixedâ�� or vice versa. We use the theorem to aid calculations in geodesy (constructing a local northâ��eastâ�� down coordinate system) and aerospace theory (relating yawâ��pitchâ��roll rates to vehicle angular velocity). The new notation here sheds light generally on the field of orientation theory, as well as giving insight to standard terms relating to wind direction used for treating ship motion. Although we present our analyses in the style of a tutorial in the general subject of spatial orientation theory, there is new notation here, along with alternative and novel ways of treating problems that are often seen as difficult or obscure by practitioners. This report follows on from the 2005 DSTO report DSTOâ��TNâ��0640, but is completely self contained, and DSTOâ��TNâ��0640 need not be read beforehand.

Executive Summary

This report is a much-evolved follow-on from the 2005 DSTO publication DSTOâ��TNâ��0640, â��Using Rotations to Build Aerospace Coordinate Systemsâ��, that explained the construction of coordinate systems used in aerospace calculations. That report followed a step-by-step approach to implement its calculations. In the current report we rephrase those calculations in a more efficient language, while incorporating a very useful theorem that is known but almost absent from the literature. This â��Pseudo-Reversing Theoremâ�� allows the order of a sequence of rotations to be reversed, provided that the sense of the axes of rotation is changed from â��bodyâ�� to â��space fixedâ�� or vice versa. The current report is self contained, so that familiarity with the content of DSTOâ��TNâ��0640 is not necessary.; The current report places the theorem and the reworked examples of DSTOâ��TNâ��0640 into the greater context of orientation/rotation theory. We first introduce the theorem, then establish a solid mathematical language necessary for quantifying the orientation of an object. We cover the background of how to rotate a vector, using either a matrix or a quaternion. We then rework the examples in DSTOâ��TNâ��0640: constructing a local northâ��eastâ��down set of axes from a given latitude and longitude, and calculating where a pilot must look to see a distant aircraft. We also make an extended revisit to the subject of conversions within the Distributed Interactive Simulation environment for handling orientation information, since this often causes problems to practitioners who must deal with several coordinate systems at once. We end the main report by showing how the Pseudo-Reversing Theorem can be used to simplify some of the concepts behind dead reckoning an objectâ��s changing orientation.; The report ends with an appendix that applies its notation and general approach to the task of constructing the appropriate course a ship must steer in order for the wind to appear to come from some given direction with some given speed. This is a nontrivial problem that is handled well in a novel way by the orientation-matrix language of this report, although its solution doesnâ��t require the Pseudo-Reversing Theorem.

Fuzzing: The State of the Art.

Report Number: DSTO-TN-1043
Author: McNally, R.; Yiu, K.; Grove, D.; Gerhardy, D.
Issue Date: 2012-02
AR Number: AR-015-148
Classification: Unclassified
Report Type: Technical Note
Division: Command, Control, Communication and Intelligence Division (C3ID)
Release Authority: Chief, Command, Control, Communication and Intelligence Division

Abstract

Fuzzing is an approach to software testing where the system being tested is bombarded with test cases generated by another program. The system is then monitored for any flaws exposed by the processing of this input. While the fundamental principles of fuzzing have not changed since the term was first coined, the complexity of the mechanisms used to drive the fuzzing process have undergone significant evolutionary advances. This paper is a survey of the history of fuzzing, which attempts to identify significant features of fuzzers and recent advances in their development, in order to discern the current state of the art in fuzzing technologies, and to extrapolate them into the future.

Executive Summary

Fuzzing is an approach to software testing where the system being tested is bombarded with test cases generated by another program. The system is then monitored for any flaws exposed by the processing of this input. Whilst such a simplistic approach may sound naive, history has shown fuzzing to be surprisingly effective at uncovering flaws in a wide range of software systems.; This combination of simplicity and effectiveness led to the wide adoption of fuzzing based approaches within the software attacker community around the turn of this century. Early fuzzing implementations tended to be relatively simple, constructing test cases from a sequence of random numbers. Driven by a desire to test increasingly sophisticated systems, the complexity of fuzzing implementations has increased to the point where there are now several recognisable classes of fuzzer, each with their own strengths and weaknesses.; With its effectiveness established, it was only a matter of time before fuzzing was incorporated into software development best practices and used as part of a software test and defensive coding regime. Several companies have developed and released commercial fuzzing tool suites, including fuzzing support for large numbers of computer protocols. This, in addition to research activies within both the academic and commercial spheres, suggests that fuzzing techniques will continue to evolve, and fuzzing will remain an important tool for vulnerability discovery in the future.; This paper is a survey of the history of fuzzing, which attempts to identify significant features of fuzzers and recent advances in their development.

Debugging and Logging Services for Defence Service Oriented Architectures.

Report Number: DSTO-TR-2664
Author: Pilling, M.
Issue Date: 2012-02
AR Number: AR-015-224
Classification: Unclassified
Report Type: Technical Report
Division: Command, Control, Communication and Intelligence Division (C3ID)
Release Authority: Chief, Command, Control, Communication and Intelligence Division

Abstract

While often thought of as a â��Dark Art", debugging is nevertheless a necessary part of fielding quality computing systems which can and should be done systematically. Service Oriented Architectures (SOAs) show great promise but also represent one of the most challenging environments in which to debug system services. In addition to all the issues of distributed and paralled de- bugging, SOAs introduce the complexity of significant parts of one's programs being provided by others. This paper examines the features of SOAs that complicate debugging and shows how integrated logging is an essential part of finding the cause of service failures. We draw on Agan's work in developing systematic strategies for debugging to generate system features that are necessary or helpful for debugging in an SOA environment. These are in turn used to specify requirements for a debugging system integrated into the fabric of the SOA. We argue that deep integration is necessary to produce significant debugging efficiency improvement in an SOA environment and provide some recommendations for Defence in this area.

Executive Summary

This document proposes an integrated distributed debugging and logging service for Defence's Service Oriented Architecture. It argues for them on the basis that:; â�¢ Debugging SOA specific issues requires integrated debugging hooks within SOA components.; â�¢ Message and event logging with vector timestamps will allow programmers fixing bugs to avoid many spurious symptoms and get a clearer picture of the problem at hand.; â�¢ Logging of application and component success or failure is essential to build up a statistical picture on which to quantify the reliability of SOA-based subsystems as a basis for fielding such subsystems for deployment.; The report also provides a software specification for such an SOA debugger. The requirements for this debugger and associated logging system are derived specifically from debugging strategies that are known to work and the information requirements that support them.; It makes several recommendations chief among them being that whatever SOA infrastructure Defence chooses, it must be flexible enough to allow Defence to modify key components in order to add functions supporting debugging and adequate logging.

Initial Trial using Embedded Fibre Bragg Gratings for Distributed Strain Monitoring in a Shape Adaptive Composite Foil.

Report Number: DSTO-TN-1070
Author: Davis, C.; Norman, P.; Kopczyk, J.; Rowlands, D.
Issue Date: 2012-02
AR Number: AR-015-236
Classification: Unclassified
Report Type: Technical Note
Division: Air Vehicles Division (AVD)
Release Authority: Chief, Air Vehicles Division

Abstract

This technical note reports on the embedment and testing of a series of distributed optical fibre sensors embedded just beneath the top and bottom surfaces of a shape adaptive composite foil. The sensors were monitored during the resin infusion and curing stages of the composite foil fabrication process. The cured foil was tested in a variable pressure water tunnel at different flow rates, angles of attack and tunnel pressures to characterise the distributed strain response of the foil to these parameters.

Executive Summary

The work described in this technical note supports the smart propeller activity in the Signatures, Materials and Energy Corporate Enabling Research Program (SME-CERP). The aim of the smart propeller activity is to develop and evaluate the capability to perform in-situ monitoring, and non-destructive evaluation, of the structural fatigue and hydrodynamic performance of composite materials.; In order to avoid the significant practical challenges associated with experimental measurements of deflection and strain on a full-scale rotating propeller, a composite foil specimen amenable to a laboratory investigation was designed to experience similar loading and deflections to a full-scale propeller blade.; The shape adaptive composite foil specimen was fabricated with a series of distributed optical fibre sensors embedded just beneath the top and bottom surfaces. The sensors were monitored during the resin infusion and curing stages of the fabrication process. The cured foil was tested in a variable pressure water tunnel at the Australian Maritime Collage (AMC) Cavitation Research Laboratory (CRL) at different flow rates, angles of attack and tunnel pressures to characterise the distributed strain response of the foil to these parameters.; This data will be used to validate the analytical techniques and manufacturing methods used in creating the foil.

Development of an Automated Impact Hammer for Modal Analysis of Structures.

Report Number: DSTO-TN-1062
Author: Norman, P.E.; Jung, G.; Ratcliffe, C.; Crane, R.; Davis, C.
Issue Date: 2012-02
AR Number: AR-015-205
Classification: Unclassified
Report Type: Technical Note
Division: Air Vehicles Division (AVD)
Release Authority: Chief, Air Vehicles Division

Abstract

Executive Summary

This report outlines the development and testing of a prototype compact automated impact hammer designed to be surface mounted on a structure to provide an impulse-based structural excitation source for vibration testing. The automated device was designed to be integrated with a distributed fibre optic sensing system which measures the in-plane dynamic strain response of the structure across a spatially dense grid of sensing points.; The work described in this report forms part of a contribution by DSTO to a re- search program on Structural Health Monitoring Through Environmental Excitation and Optical Fibre Sensors sponsored by the Office of Naval Research (ONR) under a Naval International Cooperative Opportunities in Science and Technology Program (NICOP). It is a collaborative research effort involving researchers from the US Naval Academy (USNA), Naval Surface Warfare Centre { Carderock Division (NSWCCD), the Australian Co-operative Research Centre for Advanced Composite Structures (CRCACS) and DSTO.; The ultimate goal of the three year research program is the demonstration and validation of a large area vibration-based structural health monitoring system on a large composite sub-structure using simulated environmental excitation and a network of surface-mounted fibre Bragg gratings for response measurement. This report documents an alternative excitation methodology which may be used as part of the structural health monitoring system in the absence of suitable environmental excitation.

Coherent Multilook Radar Detection for Targets in Pareto Distributed Clutter.

Report Number: DSTO-TR-2646
Author: Weinberg, G.V.
Issue Date: 2012-01
AR Number: AR-015-196
Classification: Unclassified
Report Type: Technical Report
Division: Electronic Warfare & Radar Division (EWRD)
Release Authority: Chief, Electronic Warfare & Radar Division

Abstract

The Pareto distribution has been proposed recently as a model for intensity clutter measurements, for maritime high resolution radar returns. Using the theory of spherically invariant random processes, the Neyman-Pearson optimal detector is derived. The generalised likelihood ratio test yields a simple sub- optimal approximation, and its performance is gauged against the whitening matched filter.

Executive Summary

This work supports the Microwave Radar Branchâ��s research efforts in the area of high grazing angle detection of small maritime targets from an airborne surveillance platform. It contributes to the research requirements of Task 07/040 (Support to AIR 70001). Detection of targets is a major function of radar systems, and hence detector performance is an important component in the efforts of Task 07/040. Detectors are designed to find targets within specific clutter models. Recently it was found the simple Pareto Distribution fitted high grazing angle clutter quite well. This was validated using the DSTO Ingara data, collected in a trial during 2004. Hence it is necessary to investigate the design of radar detection schemes in such a clutter environment.; The theory of spherically invariant random processes (SIRPs) puts this problem into a formulation that allows the determination of detection decision rules. The Pareto distribution is put into this framework, and the Neyman-Pearson detector is specified. Due to intractability of the latter, several suboptimal approximations are considered. The major contribution of this work is to examine coherent multilook detection under the assumption of a Pareto clutter model. Although the Pareto SIRP and form of the generalised likelihood ratio test for detection has been presented already in the literature, it has not been applied directly to the multilook problem under consideration.; In addition to this, it will be shown that for Pareto models whose parameters are typical of clutter obtained from a radar operating in vertical polarisation, the whitening matched filter is an appropriate suboptimal detector. This is useful because the generalised likelihood ratio test solution depends on clutter parameters, unlike the whitening matched filter.

Transient Eddy-Current Nondestructive Evaluation Benchmark Data for Backface Slots in a Plate.

Report Number: DSTO-TN-1047
Author: Burke, S.K.; Ibrahim, M.E.
Issue Date: 2011-12
AR Number: AR-015-159
Classification: Unclassified
Report Type: Technical Note
Division: Maritime Platforms Division (MPD)
Release Authority: Chief, Maritime Platforms Division

Abstract

The results of a benchmark experiment for transient eddy-current non-destructive evaluation are reported. The benchmark configuration corresponds to the canonical geometry of an air-cored probe coil positioned above a conductive plate containing a long back-face slot. The coil is excited by an exponentially-damped step function current and measurements are made of the change in the transient magnetic field due to the slot. The aim of the work is to provide experimental data for validation of theoretical models under development within the wider NDE community and to provide a common geometry against which the performance of a range of such models can be compared. A further aim of the work is to stimulate the ongoing development of quantitative methods in transient eddy-current research.

Executive Summary

Eddy-current testing (ET) is a well-established and reliable non-destructive evaluation (NDE) technique that is used extensively to ensure the structural integrity of military platforms. It relies on a time-varying magnetic field, produced by a probe coil, to induce eddy currents in a metallic component under test. The presence of defects such as fatigue cracks or corrosion perturb the local eddy-current distribution, leading to a change in the induced coil voltage, signalling the presence of a flaw.; The two principal variants of ET are distinguished by the time variation of the applied field. Conventional ET utilises an alternating current to excite a probe coil, and measurements are performed in the frequency domain. The emerging technique of transient eddy-current testing consists of time-domain measurements where the probe coil is excited by a pulsed current. Significant interest has been generated in the transient technique because of its potential advantages over conventional ET in circumstances such as the detection of buried defects in multi-layer metallic structures.; A range of mature numerical modelling packages can be used to predict the probe response and optimise inspection parameters for conventional ET. However, there is a distinct lack of such tools for transient eddy-current testing. Further development of the transient technique requires similar validated quantitative models to underpin probe design and inspection philosophy.; With this in mind, the aim of the present work is to provide high-quality experimental transient eddy-current data for a well-characterised benchmark configuration. These data will then be employed to validate numerical models, currently under development within the wider NDE community. The benchmark experiment also provides a common geometry against which the performance of a range of numerical models can be compared, and is expected to stimulate ongoing development of quantitative transient eddy-current methods.; The benchmark configuration is typical of the case where transient eddy-current NDE could be considered in preference to conventional eddy-current NDE. The experimental configuration and parameters for the benchmark problem are presented within the body of the report and, for ease of access, the transient magnetic field data are provided in electronic form in a series of files accompanying this report.; This work was initiated by the TTCP Technical Panel MAT-TP-5 Nondestructive Evaluation for Asset Life Extension and Integrity through the operating assignment TTCP MAT-TP-5 O33 â��Transient Eddy-current Systems.â��

Review of the MDF-LSA 100 Spray Decontamination System.

Report Number: DSTO-GD-0662
Author: Sferopoulos, R.
Issue Date: 2011-12
AR Number: AR-015-184
Classification: Unclassified
Report Type: General Document
Division: Human Protection and Performance Division (HPPD)
Release Authority: Chief, Human Protection and Performance Division

Abstract

This report was prepared to provide a general overview of the history and performance of the Modec Decontamination Foam (MDF)-LSA 100 Spray Decontamination System as well as information regarding the decontamination systems which have since superseded it.

Executive Summary

DSTO were given a sample of the Modec Decontamination Foam (MDF)-LSA 100 Spray Decontamination System and two Force 1 Deconâ�¢ products (surfactant and sodium hypochlorite) to evaluate and determine their effectiveness against chemical warfare agents (CWAs). However a laboratory-based evaluation was not undertaken due to the age of the MDF-LSA 100 sample and therefore the sampleâ��s integrity. As a result this report was prepared to provide a general overview of the history of the MDF-LSA 100 Spray Decontamination System as well as information regarding the decontamination systems which have since superseded it. This report also aims to provide brief information on the two Force 1 Deconâ�¢ products.; MDF-LSA 100, also referred to as DF-100 (Decontamination Foam -100), was the original decontamination formulation developed by Sandia National Laboratories (SNL) during the late 1990s, to provide the armed forces with a single decontaminant that would work effectively against all potential chemical and biological threats. However after testing, it became apparent that the original formulation was less than ideal as it required the pH to be adjusted for optimal decontamination of each specific chemical and biological agent and the formulation was found to degrade sulfur mustard at a relatively slow rate. In late 2000, an enhanced version of the DF-100 was developed, called DF-200 or MDF-LSA 200, which took into account the aforementioned problems.; The MDF-LSA 200 formulation was confirmed by SNL as effective on G agents, VX, sulfur mustard and anthrax simulants, however the EPA found that the formulation was ineffective against anthrax. As yet there have been no independent evaluations on the effectiveness of this new formulation to decontaminate CWAs. Furthermore an MDF 300 concentrate is currently under development.; The two Force 1 Deconâ�¢ products, provided to DSTO as refills for the MDF-LSA 100, were found not to be refills, rather they form part of a number of decontamination kits sold by Force 1 Deconâ�¢. These products were not evaluated.

Applications of Historical Analyses in Combat Modelling.

Report Number: DSTO-TR-2643
Author: Perry, N.
Issue Date: 2011-12
AR Number: AR-015-190
Classification: Unclassified
Report Type: Technical Report
Division: Joint Operations Division (JOD)
Release Authority: Chief, Joint Operations Division

Abstract

While Lanchesterâ��s equations are commonly used as the basis for force-on-force combat models, it is important to remember that Lanchesterâ��s Equations are not a model of combat, only a model for combat attrition. There have been numerous attempts to compare historical combat data with the behaviour expected from Lanchester's Equations. The present work extends this comparison between historical battle data with behaviour expected from a battle where attrition is described by Lanchesterâ��s Equations. It examines how analyses of historical battles can contribute to the development of models of combat and hence our understanding of combat in addition to the processes used in the creation of databases of historical battle results. The historical data is compared against the expectations of both the deterministic and stochastic forms of Lanchesterâ��s Square Law.

Executive Summary

Lanchesterâ��s equations are commonly used as the basis for force-on-force combat models, even if only as a metamodel for a more complex combat model. It is important to remember that Lanchesterâ��s Equations are not a model of combat, only a model for combat attrition. The equations alone, therefore, cannot be expected to capture other effects such as the movement of engaged forces. There have been numerous attempts to compare historical combat data with the behaviour expected from combat models. To validate differential models of attrition, force and casualty numbers for both sides intermediate to the starting and finishing values are required. That level of detail is rarely available and often does not exist. An alternate approach using only the initial and final values of engaged forceâ��s strength has been tried previously. However, Lanchesterâ��s Equations describe the behaviour of a single system in time while the historical databases contain information about an ensemble of battles, each potentially with different values of attrition rate coefficients. The issue of why the results from such an ensemble follow the behaviour expected from Lanchesterâ��s Equations has never been adequately explored or explained.; The present work extends this comparison between historical battle data with behaviour expected from a battle where attrition is described by Lanchesterâ��s Equations. It examines how analyses of historical battles can contribute to the development of models of combat and hence our understanding of combat in addition to consideration of the processes that are used in the creation of databases of historical battle results. The implications of those processes on the limitations of this form of analysis, the constraints they impose and the resulting inherent biases are discussed, as well as methods that can be used to quantify and mitigate their effects.; The historical data is compared against the expectations of both the deterministic and stochastic forms of Lanchesterâ��s Square Law. However, it should be noted that examination of Lanchesterâ��s stochastic differential equation was not intended to be comprehensive or rigorous. Both have been covered extensively elsewhere, including by the author, and the present work contains numerous references to more authoritative works on these subjects for the interested reader.; Finally, evidence for considering battle as a particular type of complex adaptive system, one that involves co-evolution and scale free behaviours, is examined. It is proposed that this may be responsible for the unexpected observation that the behaviour of several parameters used to characterise combat is the same for both an ensemble of different battles and for the evolution of a single battle.