Digital Commons Network^™

Why Software Engineering Is Riskier Than Ever, A. Fuller, P. Croll, O. Garcia

Faculty of Informatics - Papers (Archive)

The ultimate aim of software engineering methods and tools is to reduce risks associated with the development of software products. Accepted risk management procedures recognize that software development is inherently risky, however fail to take into account the changing nature of both software products and the organizations undertaking their development. SE research has traditionally focused on the needs of very large corporations undertaking equally mammoth and complex development projects, thus most tools and methods are predicated on this model. Yet most software development is undertaken by small to medium enterprises. Consequently, these development efforts are either undertaken with little or …

A New Cryptanalytic Method Using The Distribution Characteristics Of Substitution Distances, B. Song, H. Wang, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

In this paper, we suggest a new method for cryptanalysis of the basic structures of the block ciphers having SP network structure. The concept of the substitution difference is introduced and the distribution characteristics of substitution distances in an S-box is developed. This gives clues for cryptanalysis of the cipher. We then examine if this method is applicable to cryptanalysis of Rijndael. We present the method for cryptanalysis of the first round of Rijndael including the initial Round-Key addition part in order to illustrate our new method.

Minimising Attainment Deficit: A Leadership Process Theory, George K. Kriflik, Robert Jones

Faculty of Commerce - Papers (Archive)

Leadership as a process was found by RTA workers to fulfill their need for attaining their potential in their jobs. This article presents an overview of this substantive theory which emerged during a Grounded Theory study. Minimising Attainment Deficit, the process, comprises a number of Leader Strategies which aim to modify workplace conditions and so alter workers’ behaviours. The fundamental premise of this theory is the workers’ perceptions of their own potential and their perception of what they are currently achieving, and that any shortfall in achievement results in an Attainment Deficit. Minimising Attainment Deficit Unleashes workers to achieve higher …

Discovery Of Ghost Cavities In The X-Ray Atmosphere Of Abell 2597, B. R. Mcnamara, M. W. Wise, P. Nulsen, L. P. David, C. L. Carilli, C. L. Sarazin, C. P. O'Dea, J. Houck, M. Donahue, S. Baum, M. Voit, R. W. O'Connell, A. Koekemoer

Faculty of Engineering - Papers (Archive)

A Chandra image of the central 100 kpc of the Abell 2597 cluster of galaxies shows bright irregular X-ray emission within the central dominant cluster galaxy (CDG) and two low surface brightness cavities located 30 kpc from the nucleus of the CDG. Unlike the cavities commonly seen in other clusters, the "ghost" cavities in Abell 2597 are not coincident with the bright central radio source. Instead, they appear to be associated with faint extended radio emission seen in a deep Very Large Array radio map. We interpret the ghost cavities as buoyantly rising relics of a radio outburst that occurred …

Plant Acoustic Density Profile Model Of Ctfm Ultrasonic Sensing, Phillip J. Mckerrow, N. Harper

Faculty of Informatics - Papers (Archive)

Many applications require the sensing of plants. When an ultrasonic sensor insonifies a plant, the resultant echo is the superposition of the echoes from the leaves. As a result, the echo contains information about the geometric structure of the foliage. In this paper, we present a model of sensing that facilitates the extraction of geometric features from the echo for plant classification, recognition and discrimination. We model the echo from a CTFM ultrasonic sensor with the acoustic density profile model. Then, we identify a set of features that represent plant geometric characteristics and use these to perform an inverse transform …

Fuzzy Clustering Evaluation Of Time-Frequency Distribution (Tfd) Schemes For Audio Stream Segregation, M. A. Jackson, I. Burnett

Faculty of Informatics - Papers (Archive)

Audio stream segregation is a task performed constantly by the human auditory system, yet is difficult to reproduce with a computer. The research detailed in this paper looks at performing just one method of stream segregation - the temporal coherence boundary - using a fuzzy clustering system. The main focus of the paper is on examining the effectiveness of several time-frequency distributions as the feature vectors for the system. Three time-frequency distributions are examined and their effectiveness evaluated in terms of correct separation and computational complexity. The main evaluation compares the popular gamma-tone filter bank with the MPEG-7 audio spectrum …

Using Boosting To Simplify Classification Models, V. Wheway

Faculty of Informatics - Papers (Archive)

Ensemble classification techniques such as bagging, boosting and arcing algorithms have been shown to lead to reduced classification errors on unseen cases and seem immune to the problem of overfitting. Several explanations for the reduction in generalisation error have been presented, with recent authors defining and applying diagnostics such as "edge" and "margin". These measures provide insight into the behaviour of ensemble classifiers, but can they be exploited further? In this paper, a four-stage classification procedure in introduced, which is based on an extension of edge and margin analysis. This new procedure allows inverse sub-contexts and difficult border regions to …

Control Of Servo Systems In The Presence Of Motor-Load Inertia Mismatch, Jeffrey W. Moscrop, C. Cook, P. Moll

Faculty of Informatics - Papers (Archive)

There are a number of performance limiting factors that concern the designers of machine tool servo systems. One such factor is the mismatch that often exists between motor and load inertias. This paper briefly discusses the results of a previous study on the factors that interact to introduce stability problems in the presence of a high motor-load inertia mismatch. The effects of such an inertia mismatch, on servo system performance, are then discussed and analysed using closed loop frequency responses. Various methods of improving the system response using fast feedback control are presented, including traditional PI control and modern methods …

An Optimal Importance Sampling Method For A Transient Markov System, H. Qi, Y. C. Wei, L. Wei

Faculty of Informatics - Papers (Archive)

In this paper an optimal importance sampling (IS) method is derived for a transient markov system. Several propositions are presented. It is showned that the optimal IS method is unique, and it must converge to the standard Monte Carlo (MC) simulation method when the sample path length approaches infinity. Therefore, it is not the size of the state space of the Markov system, but the sample path length, that limits the efficiency of the IS method. Numerical results are presented to support the argument.

Bulk Stress Due To Surface Damage Of Crystalline Silicon And Germanium, P. Fisher, R. Vickers

Faculty of Engineering - Papers (Archive)

It is found that abrading two opposing surfaces of either crystalline Si or Ge samples results in homogeneous, uniaxial stress throughout the bulk perpendicular to the damaged surfaces. The latter are chosen to coincide with simple crystallographic planes. This conclusion is reached by analyzing the splittings, intensities, and polarizations of the absorption lines of the Lyman series of bulk shallow impurities in the abraded semiconductors. This effect has been observed for samples which range in thickness, t, from 1 to 3 mm, the internal stress being proportional to t–1.

New Results On Frame-Proof Codes And Traceability Schemes, R. Safavi-Naini, Yejing Wang

Faculty of Informatics - Papers (Archive)

In this correspondence we derive lower bounds on the maximum number of codewords in a class of frame-proof codes and traceability schemes, and give constructions for both with more codewords than the best known.

Function Spaces And Multiplier Operators, R. Nillsen, S. Okada

Faculty of Informatics - Papers (Archive)

Let G denote a locally compact Hausdorff abelian group. Then a bounded linear operator T from L^2(G) into L^2(G) is a bounded multiplier operator if, under the Fourier transform on L^2(G ), for each function f in L^2(G), T(f) changes into a bounded function U times the Fourier transform of f. Then U is called the multiplier of T. An unbounded multiplier operator has a similar definition, but its domain is a dense subspace of L^2(G) and the multiplier function need not be bounded. For example, differentiation on the first order Sobolev subspace of L^2(R) is an unbounded multiplier operator …

University Of Wollongong Campus News [November?] 2001, University Of Wollongong

University of Wollongong Campus News

No abstract provided.

Assessing Hybrid Classes In A Flexible Learning Environment, M. Lawrence-Slater

Faculty of Informatics - Papers (Archive)

This paper describes the development of a regime comprising a teaching platform and associated assessment processes. The objective behind these is to enable the equitable assessment of student assignments in hybrid courses. In this paper, the term hybrid refers to courses where the student body comprises both campus-based and off-campus students. Additionally, in either of these groups students may elect to undertake their studies using online resources rather than attend in person. The paper commences with a background discussion on the problem and reasons for seeking alternative approaches to teaching and assessment in hybrid courses. This is followed by a …

Keeping Our Academics On The Cutting Edge: The Academic Outreach Program At The University Of Wollongong Library, Suzanne M. Lipu, Elizabeth H. Peisley

Senior Deputy Vice-Chancellor and Deputy Vice-Chancellor (Education) - Papers

In the higher education sector, developing students' information literacy skills has been a hot issue in policy making and program development for almost a decade. But how do academic staff develop and maintain their information literacy skills? How do they cope in an increasingly electronic environment? In 1999 the University of Wollongong Library introduced an ambitious program coined Academic Outreach which targeted 100% of academics campus-wide. Identified as a strategic initiative of the Reference Services team, the program was designed to keep our academics on the cutting edge of information sources in their field. The aim was to help them …

Keeping A Global Technology Working: A Study Into The Social And Technical Dimensions Of Broadcast Engineering In The Pacific Islands, William Tibben

Faculty of Informatics - Papers (Archive)

This paper is primarily concerned with exploring the technical and social dimensions of problem solving undertaken by technical staff in a Pacific Island radio station. Essentially, the paper addresses the question "what influence do physical and social contexts have on engineering knowledge development?". The paper notes that the concept of context is not given significant attention when looking to dominant philosophies of engineering. This stands in contrast to the importance accorded to context in development literature, particularly in. relation to technological knowledge. Using Macdonald's research into the role of information in innovation, the paper identifies a number of factors besides …

Towards Securing 3g Mobile Phones, R. Safavi-Naini, Willy Susilo, G. Taban

Faculty of Informatics - Papers (Archive)

Third-generation (3G) mobile phones are capable of high data rate Internet connection and promise seamless connectivity for a free roaming user. They can provide an "always on" Internet, and make a range of services, traditionally available on desktop computers, accessible to mobile users, irrespective of their location. Providing adequate security for these phones and the services that they offer is a central concern for their acceptability and uptake. We briefly review the security of second generation mobile phones and then discuss security architecture proposed for 3G phones. The new security issues that are of importance because of the combination of …

On Multiple Watermarking, Nicholas Paul Sheppard, Reihaneh Safavi-Naini, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

Mintzer and Braudaway once asked: If one watermark is good, are more better? In this paper, we discuss some techniques for embedding multiple watermarks into a single multimedia object and report some observations on implementations of these techniques.

Simulation Of Capture Behaviour In Ieee 802.11 Radio Modems, C. Ware, Joe F. Chicharo, Tadeusz A. Wysocki

Faculty of Informatics - Papers (Archive)

In this paper we investigate the performance of common capture models in terms of the fairness properties they reflect across contenting hidden connections. We propose a new capture model, Message Retraining,as a means of providing an accurate description of experimental data. Using two fairness indices we undertake a quantitative study of the accuracy with which each capture model is able to reflect experimental data. Standard capture models are shown to be unable to accurately reflect the fairness properties of empirical data. The Message Retraining capture model is shown to provide a good estimate of actual system performance in varying signal …

Optimization Of Orthogonal Polyphase Spreading Sequences For Wireless Data Applications, Beata J. Wysocki, Tadeusz A. Wysocki

Faculty of Informatics - Papers (Archive)

We propose a simple but efficient method for optimizing correlation properties of polyphase spreading sequences for asynchronous DS CDMA applications. The proposed method can be used to minimize the mean square value of aperiodic crosscorrelation or the mean square value of aperiodic autocorrelation, the maximum value of aperiodic crosscorrelation functions, merit factor or other properties of the sequence set. The important feature of the method is that when applied to orthogonal sequences, it modifies correlation properties of the sequence set, while it preserves their orthogonality for perfect synchronization.

Outlook University Of Wollongong Alumni Magazine October 2001, University Of Wollongong

Wollongong Outlook: The University Alumni Magazine

No abstract provided.

Impact Evaluation Of A Folate Education Campaign With And Without The Use Of A Health Claim, P. G. Williams, J. Mchenery, Anne Mcmahon, H. Anderson

Faculty of Health and Behavioural Sciences - Papers (Archive)

Objective To measure the impact of a Kellogg/Northcott Society multimedia folate education campaign, run nationally from July 1998 to June 1999, with and without the use of health claims.

Method Three national telephone surveys of over 500 Australian women aged 18-44 in July and November 1998 and May 1999.

Results Awareness of the role of folate in the prevention of birth defects rose by 8% in the first 6 months of the campaign (without health claims) and by 15% in the second half (when health claims were incorporated). Awareness of the recommendation to take folate before pregnancy rose from 21% …

Using Olap And Multidimensional Data For Decision Making, Helen M. Hasan, P. Hyland

Faculty of Commerce - Papers (Archive)

Managers see information as a critical resource and require systems that let them exploit it for competitive advantage. One way to better use organizational information is via online analytical processing and multidimensional databases (MDDBs). OLAP and MDDBs present summarized information from company databases. They use multidimensional structures that let managers slice and dice views of company performance data and drill down into trouble spots. For over a decade, proponents have touted these tools as the ultimate executive information system, but most of the hype comes from product vendors themselves. Based on our experience with several OLAP tools, we have developed …

Nonviolent Futures, Brian Martin

Faculty of Arts - Papers (Archive)

Nonviolent action - including methods such as rallies, strikes, boycotts and sit-ins - has become increasingly important in the past century as a method for waging conflict and promoting social change. Nonviolent action has been adopted by many social movements, yet its potential impact has only begun to be realised. Some areas for future expansion of the role of nonviolent action include replacing military defence, technological design, challenging capitalism, bureaucratic politics, information struggles and interpersonal behaviour.

Magneto-Optical Franz-Keldysh Effect Of An Electron Gas Subjected To Quantizing Magnetic Fields And Intense Terahertz Laser Fields, W. Xu

Faculty of Engineering - Papers (Archive)

When a three-dimensional electron gas is subjected to quantizing magnetic fields and intense laser fields in the Faraday geometry, the maximum electron density of states will be shifted by an energy Eem (eF0)2/4m*(2c 2), where and F0 are, respectively, the frequency and the electric-field strength of the laser field and c is the cyclotron frequency. This will result in a shift in the fundamental absorption edge by Eem , known as the magneto-optical Franz-Keldysh effect MOFKE. In this paper, the MOFKE is studied theoretically for a semiconductor-based electron gas system where terahertz free-electron lasers are employed as intense laser radiation …

Cognitive Considerations For Effective Methods Of Learning Kanji For Non-Native Learners Of Japanese, H. Kaiho, G. Haththotuwa Gamage

Faculty of Arts - Papers (Archive)

The learning of Chinese characters (Kanji) is one of the most difficult problems for learners from non-Kanji backgrounds．In this study, the difficulties are examined from a cognitive perspective and several promising proposals for learning Kanji are offered with respect to (1) problems originating in the Kanji characters themselves, and　(2) problems associated with learning environments．

A High-Resolution Study Of The Hydra A Cluster With Chandra: Comparison Of The Core Mass Distribution With Theoretical Predictions And Evidence For Feedback In The Cooling Flow, L. P. David, P. Nulsen, B. R. Mcnamara, W. Forman, C. Jones, T. Ponman, B. Robertson, M. Wise

Faculty of Engineering - Papers (Archive)

The cooling flow cluster Hydra A was observed during the orbital activation and calibration phase of the Chandra Observatory. While the X-ray image of the cluster exhibits complex structure in the central region as reported in McNamara et al., the large-scale X-ray morphology of the cluster is fairly smooth. A spectroscopic analysis of the ACIS data shows that the gas temperature in Hydra A increases outward, reaches a maximum temperature of 4 keV at 200 kpc, and then decreases slightly at larger radii. The distribution of heavy elements is nonuniform, with a factor of 2 increase in the Fe and …

Visualization As A Key Element In Learning, J. Fulcher

Faculty of Informatics - Papers (Archive)

Experience with teaching undergraduate and postgraduate computer science (CS) subjects has shown that students benefit substantially from being able to visualize fundamental topics. Examples are presented from five different CS areas, namely: (i) communications, (ii) parallel computing, (iii) artificial neural networks, (iv) genetic algorithms and (v) data mining. The majority of these examples stemmed from student projects, rather than commercial software products. Accordingly, students benefit twofold from the visually-oriented subject presentations, firstly in facilitating the learning of basic concepts, and secondly in the development of educational software packages as part of their project work.

The Advantage Of Industrial R&D In The Training Of University Students, J. Fulcher

Faculty of Informatics - Papers (Archive)

Experience gained through industrial R&D projects supports the proposition that several benefits flow through to both students and faculty staff beyond that of simply providing associated student project titles. To be more specific, enhancing lecture material with not only specific research findings but also general experience gained from working on such projects are secondary benefits of such university-industry links. Moreover, the reputation and standing of both individual researchers and university research groups are further enhanced by such relationships. This in turn often leads to subsequent industrial R&D projects (and so the cycle continues...).

Scalable Audio Coding Employing Sorted Sinusoidal Parameters, M. Raad, I. Burnett, Alfred Mertins

Faculty of Informatics - Papers (Archive)

This paper describes the use of sorted sinusoidal parameters to produce a fixed rate, scalable, wideband audio coder. The sorting technique relies on the perceptual significance of the sinusoidal parameters. Sinusoidal coding permits the representation of a given signal through the summation of sinusoids. The parameters of the sinusoids (the amplitudes, phases and frequencies) are transmitted to allow signal reconstruction. The sinusoidal parameters are sorted according to energy content and perceptual significance. The most significant parameters are transmitted first, allowing the use of only a small set of the parameters for signal reconstruction. The proposed scheme incurs a low delay …