Computer Science, Engineering and Mathematics

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The School of Computer Science, Engineering and Mathematics is a multidisciplinary school focussing on best practice teaching, research, research training and consulting in the areas of Computer Science, Engineering, Information Technology, Mathematics and Statistics.

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Browsing Computer Science, Engineering and Mathematics by Title

Now showing 1 - 20 of 249
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    An 180 MHz 16 bit multiplier using asynchronous logic design techniques
    (Institute of Electrical and Electronics Engineers Computer Society (IEEE Publishing), 1994) Burford, Richard G ; Fan, Xingcha ; Bergmann, Neil W
    A CMOS digital logic design technique is described which exploits the advantages of fast precharged logic and efficient latch design commonly used in synchronous systems while maintaining the features of localized control inherent in asynchronous design. A pipelined sixteen bit multiplier is presented and its performance compared with several previously reported asynchronous and synchronous designs.
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    The 7Li(p,n)7 Be Reaction as a Source of Fast Neutrons for Smaller Compact Cyclotrons
    (Institute of Electrical and Electronics Engineers Computer Society (IEEE Publishing), 1979) Chaudhri, M Anwar ; Templer, J. ; Rouse, J L
    The usefulness of the 7Li(p,n)7Be reaction as a fast neutron source for applications, such as neutron therapy etc., using smaller compact cyclotrons (proton energies of up to 15-18 MeV) has been investigated by measuring thin and thick target neutron spectra, absolute cross sections and angular distributions of various neutron groups produced in this reaction at 10.45 MeV. Our results indicate that the forward direction is still the preferred one for obtaining the most suitable fast neutron beam for biomedical application, and that moderately thick, rather than infinitely thick, target would provide higher mean energy. Moreover, it has also been shown that the 7Li(p,n)7 Be reaction is more suited for producing neutron beams for therapy than proton and deuteron induced reactions on Be at corresponding energies, and that a therapeutically useful neutron beam can be produced even with smaller compact cyclotrons.
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    A-band methyl halide dissociation via electronic curve crossing as studied by electron energy loss spectroscopy
    (American Institute of Physics, 2010) Kato, Hisaaki ; Masui, Hisashi ; Hoshino, Masahiro ; Cho, Hyuck ; Ingolfsson, Oddur ; Brunger, Michael James ; Limao-Vieira, Paulo ; Tanaka, Hiroshi
    Excitation of the A-band low-lying electronic states in the methyl halides, CH3I, CH3Br, CH3Cl, and CH3F, has been investigated for the (n→σ∗) transitions, using electron energy loss spectroscopy (EELS) in the range of 3.5–7.5 eV. For the methyl halides, CH3I, CH3Br, and CH3Cl, three components of the Q complex (3Q1, 3Q0, and 1Q1) were directly observed, with the exception of methyl fluoride, in the optically forbidden EELS experimental conditions of this investigation. The effect of electronic-state curve crossing emerged in the transition probabilities for the 3Q0 and 1Q1 states, with spin-orbit splitting observed and quantified against results from recent ab initio studies.
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    Active vibration absorber design via sliding mode control
    (Institute of Electrical and Electronics Engineers Computer Society (IEEE Publishing), 2000) Cao, Tri-Tan Van ; Chen, Lei ; He, Fangpo ; Sammut, Karl
    A new, simple control method for vibration absorber design is presented. A nonlinear robust control scheme based on a variable structure is designed and simulated. Robust synthesis of the discontinuity surface based on classical frequency loop-shaping and the edge theorem is discussed. The proposed control scheme has two advantages over the current existing vibration absorber design methodologies: 1) it is completely insensitive to changes in the stiffness and damping of the absorber, and strongly robust against parametric uncertainties of the primary vibrating structure; and 2) it is capable of suppressing both cyclic and random vibrations over a very wide range of frequencies.
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    Adabook and Multibook: adaptive boosting with chance correction
    ( 2013-09) Powers, David Martin
    There has been considerable interest in boosting and bagging, including the combination of the adaptive techniques of AdaBoost with the random selection with replacement techniques of Bagging. At the same time there has been a revisiting of the way we evaluate, with chance-corrected measures like Kappa, Informedness, Correlation or ROC AUC being advocated. This leads to the question of whether learning algorithms can do better by optimizing an appropriate chance corrected measure. Indeed, it is possible for a weak learner to optimize Accuracy to the detriment of the more reaslistic chance-corrected measures, and when this happens the booster can give up too early. This phenomenon is known to occur with conventional Accuracy-based AdaBoost, and the MultiBoost algorithm has been developed to overcome such problems using restart techniques based on bagging. This paper thus complements the theoretical work showing the necessity of using chance-corrected measures for evaluation, with empirical work showing how use of a chance-corrected measure can improve boosting. We show that the early surrender problem occurs in MultiBoost too, in multiclass situations, so that chance-corrected AdaBook and Multibook can beat standard Multiboost or AdaBoost, and we further identify which chance-corrected measures to use when.
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    Adaptive Asymptotical Synchronization for Stochastic Complex Networks with Time-Delay and Markovian Switching
    (Hindawi, 2014-06-04) Jiang, Xueling ; Qin, Shuijie ; Tong, Dongbing ; Wang, Liping
    The problem of adaptive asymptotical synchronization is discussed for the stochastic complex dynamical networks with time-delay and Markovian switching. By applying the stochastic analysis approach and the M-matrix method for stochastic complex networks, several sufficient conditions to ensure adaptive asymptotical synchronization for stochastic complex networks are derived. Through the adaptive feedback control techniques, some suitable parameters update laws are obtained. Simulation result is provided to substantiate the effectiveness and characteristics of the proposed approach.
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    Adaptive integral sliding mode control for active vibration absorber design
    (Institute of Electrical and Electronics Engineers Computer Society (IEEE Publishing), 2000) Cao, Tri-Tan Van ; Chen, Lei ; He, Fangpo ; Sammut, Karl
    A new tuning method for active vibration absorber design is presented in this paper. A robust, adaptive control scheme based on a variable structure with an adaptive discontinuity surface is designed and simulated. Robust synthesis of an adaptive discontinuity surface based on an augmented state-space is discussed. The proposed tuning scheme has three superior features compared with the existing counterparts in that: (i) it is completely insensitive to changes in the stiffness and damping of the absorber, (ii) it is capable of suppressing cyclic vibrations over a wide range of frequencies, (iii) its real-time operation requires only one adjustable gain.
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    Adaptive order-statistics multi-shell filtering for bad pixel correction within CFA demosaicking
    (Institute of Electrical and Electronics Engineers Computer Society (IEEE Publishing), 2009) Li, Jimmy Siu ; Randhawa, Sharmil
    As today's digital cameras contain millions of image sensors, it is highly probable that the image sensors will contain a few defective pixels due to errors in the fabrication process. While these bad pixels would normally be mapped out in the manufacturing process, more defective pixels, known as hot pixels, could appear over time with camera usage. Since some hot pixels can still function at normal settings, they need not be permanently mapped out because they will only appear on a long exposure and/or at high ISO settings. In this paper, we apply an adaptive order-statistics multi-shell filter within CFA demosaicking to filter out only bad pixels whilst preserving the rest of the image. The CFA image containing bad pixels is first demosaicked to produce a full colour image. The adaptive filter is then only applied to the actual sensor pixels within the colour image for bad pixel correction. Demosaicking is then re-applied at those bad pixel locations to produce the final full colour image free of defective pixels. It has been shown that our proposed method outperforms a separate process of CFA demosaicking followed by bad pixel removal.
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    Adsorption behavior of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin on pristine and doped black phosphorene: A DFT study
    (Elsevier, 2017-07-03) Zhang, Hong-ping ; Hou, Jia-liang ; Wang, Yaobin ; Tang, Ping-ping ; Zhang, Ya-ping ; Lin, Xiao-yan ; Liy, Changsheng ; Tang, Youhong
    Polychlorinated dibenzo-p-dioxins (PCDDs) are highly toxic to humans. The search for novel and effective methods and materials for detecting or removing these gas pollutants is becoming more important and urgent. With its high specific surface area, abundance, and variety of potential applications, phosphorene has attracted much research interest. In this study, density functional theory was used to study the interactions between a doped phosphorene sheet and a tetrachlorodibenzo-p-dioxin (TCDD) molecule. The initial configurations of the TCDD and metallic (Ca or Ti) or nonmetallic (S and Se) dopants were investigated during the TCDD–phosphorene interaction study. Adsorption energy, isosurface of electron density difference, and density of states analysis were utilized to explore the interactions between TCDD and phosphorene. The results indicated that Ca dopant effectively improved the interaction between TCDD and phosphorene. Se dopant reduced the interaction between TCDD and phosphorene. Combining interactions between TCDD and the pristine, Ca-doped, and Se-doped phosphorenes, phosphorene could be a promising candidate for TCDD sensing and removal.
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    Aggregation-disaggregation algorithm for e2-singularly perturbed limiting average Markov control problems
    (Institute of Electrical and Electronic Engineers, 1991) Abbad, Mohammed ; Filar, Jerzy A
    In this paper we consider a singular perturbation of order 2 for a Markov decision process with the limiting average reward criterion. We define a singular perturbation of order 2 in the following sense: we assume that the underlying process is composed of n separate irreducible processes, and that a small e-perturbation is such that it ”unites” these processes into m separate irreducible processes. Then another small e2-perturbation is such that it “unites” these latter processes into a single irreducible process. The present paper is organized as follows: In Section 2, we formulate the singular perturbation of order 2. In Section 3, we give explicitly the limit Markov Control Problem (limit MCP), that is entirely different from the original unperturbed MDP, which forms an appropriate asymptotic approximation to a whole family of perturbed problems. Thus only the single limit MCP needs to be solved.
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    An algorithm for solving S-games and differential S-games
    (Institute of Electrical and Electronic Engineers, 1982) Filar, Jerzy A ; Raghavan, Thirukkannamangai Eachambadi S
    We present an algorithm for solving S-Games. Our algorithm can be used to compute approximately the value of the game as well as €-optimal strategies of the two players. For games with similar structure to S-games which do not necessarily possess a value, the algorithm can sometimes be used as a heuristic procedure for determining the existence of a minimax solution. Further, it is shown that a certain simple class of differential games (we call them "differential S-games") can be viewed as static games and solved by the above procedure.
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    Algorithms for Robust Pole Assignment in Singular Systems
    (Institute of Electrical and Electronics Engineers Computer Society (IEEE Publishing), 1986) Kautsky, Jaroslav ; Nichols, N.K.
    The solution of the pole assignment problem by feedback in singular systems is parameterized and conditions are given which guarantee the regularity and maximal degree of the closed loop pencil. A robustness measure is defined, and numerical procedures are described for selecting the free parameters in the feedback to give optimal robustness.
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    Algorithms for singularly perturbed limiting average Markov Control Problems
    (Institute of Electrical and Electronic Engineers, 1990) Abbad, Mohammed ; Filar, Jerzy A ; Bielecki, Tomasz R
    The authors consider a singularly perturbed Markov decision process (MDP) with the limiting average cost criterion. It is assumed that the underlying process is composed of n separate irreducible processes, and that the small perturbation is such that it 'unites' these processes into a single irreducible process. This structure corresponds to the Markov chains admitting strong and weak interactions. The authors introduce the formulation and some results given by Bielecki and Filar (1989) for the underlying control problem for the singularly perturbed MDP, the limit Markov control problem (limit MCP). It is demonstrated that the limit MCP can be solved by a suitably constructed linear program. An algorithm for solving the limit MCP based on the policy improvement method is constructed.
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    Analysing homogenous patient journeys to assess quality of care for patients admitted outside of their ‘home-ward’
    (Australian Computer Society, 2013) Perimal-Lewis, Lua ; Qin, Shaowen ; Thompson, Campbell Henry ; Hakendorf, Paul Haylett
    This study is the first to explore the quality of care based on the outlier or the inlier status of patients for a large heterogeneous General Medicine (GM) service at a busy public hospital. The study compared the quality of care between ward outliers and ward inliers based on a homogenous group of patients using Two-step clustering method. Contrary to common perception, ward outliers had overall shorter Length of Stay (LOS) than ward inliers. The study also was unable to support the perception of shorter LOS in the outlier group being associated with higher in-hospital mortality. The study confirmed that overall the outliers received inferior quality of care as discharge summaries for the outliers were delayed and more outliers were re-admitted within 7 days of discharge in comparison to the inliers.
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    An analysis of application rates to programs in information technology, science, and engineering
    (Institute of Electrical and Electronics Engineers Computer Society (IEEE Publishing), 2001) Roddick, John Francis ; Nieuwenhuis, Adrienne L
    A shift away from generic undergraduate degrees toward an emphasis on vocationally oriented qualifications has been evident in the awards offered by higher education institutions in Australia over the past few years. This has included those in information technology, science and engineering, where the growth in the number of, and variation in, awards has been particularly evident. The past few years have also seen a general, and in some cases significant, decline in the application rates for some forms of science and engineering. This has prompted many institutions to look at their awards with a view to making them more attractive, both to students and industry, often through the development of more highly specialized awards. In this paper, the authors investigate application trends for information technology, science and engineering awards from a number of perspectives, including the market perceptions of the institution offering the degree. Although the paper focuses on three broad categories of awards - information technology, science and engineering - some lessons may be appropriate for other disciplines. Moreover, although this study takes advantage of the centralized admissions systems used in Australia, available indicators show that the results may well be applicable in the United States and the U.K. and possibly elsewhere.
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    An analysis of FPGA-based custom computers for DSP applications
    (Institute of Electrical and Electronics Engineers Computer Society (IEEE Publishing), 1994) Bergmann, Neil W ; Mudge, Craig
    Field programmable gate arrays (FPGAs) can be rapidly reconfigured to provide different digital logic functions. When such FPGA logic circuits are incorporated within a stored-program computer, the result is a machine where the programmer can design both the software and the hardware that will execute that software. This paper first surveys this area of custom computing. It then describes a new custom computing architecture which uses a processing node with three sections: a standard arithmetic chip, static RAM and reconfigurable logic for operand handling. Finally an analysis of the suitability of this new approach for implementation of DSP applications shows it to be worthy of further investigation.
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    Analytic perturbations and systematic bias in staistical modeling and inference
    (Institute of Mathematical Statistics, 2008) Filar, Jerzy A ; Hudson, Irene ; Mathew, Thomas ; Sinha, Bimal
    In this paper we provide a comprehensive study of statistical inference in linear and allied models which exhibit some analytic perturbations in their design and covariance matrices. We also indicate a few potential applications. In the theory of perturbations of linear operators it has been known for a long time that the so-called “singular perturbations” can have a big impact on solutions of equations involving these operators even when their size is small. It appears that so far the question of whether such undesirable phenomena can also occur in statistical models and their solutions has not been formally studied. The models considered in this article arise in the context of nonlinear models where a single parameter accounts for the nonlinearity.
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    Application rates to undergraduate programs in Information Technology in Australian universities
    (Australian Computer Society, 2001) Roddick, John Francis ; Nieuwenhuis, Adrienne L
    Over the past decade, there has been much discussion regarding both the supply and the current and potential demand for information technology-oriented graduates in Australia with numerous surveys and market analyses being undertaken. Some surveys have focussed on the supply of graduates from the tertiary and VET sectors and their demand in Australian industry, while others discuss enrolment statistics into IT based University and VET sector courses. Few, however, investigate application rates to IT courses. At the same time, there has been a general, and in some cases significant, decline in the application rates for some science and engineering courses prompting universities to review their awards with a view to making them more attractive to students and industry. Although this study takes advantage of the centralised admissions systems used in Australia, data available elsewhere shows that the results may be applicable more broadly.
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    Architecture design of a fully asynchronous VLSI chip for DSP custom applications
    (Institute of Electrical and Electronics Engineers Computer Society (IEEE Publishing), 1992) Fan, Xingcha ; Bergmann, Neil W
    A fully asynchronous, distributed VLSI architecture is introduced for dedicated real-time digital signal processing applications. The architecture is based on a data-driven computing model to allow maximum exploitation of the fine-grained concurrency. An asynchronous, self-time signaling protocol is used in the architecture to naturally match data-driven computing and circumvent the clock skew problem. After a brief description of the architecture, key issues of the architecture, such as the interconnection network, data identification, and operand matching are discussed. Finally, disadvantages of the architecture and future work are outlined.
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    An artificial neural network system to identify alleles in reference electropherograms
    (Elsevier, 2017-07-06) Taylor, Duncan A ; Harrison, A ; Powers, David Martin
    Electropherograms are produced in great numbers in forensic DNA laboratories as part of everyday criminal casework. Before the results of these electropherograms can be used they must be scrutinised by analysts to determine what the identified data tells them about the underlying DNA sequences and what is purely an artefact of the DNA profiling process. This process of interpreting the electropherograms can be time consuming and is prone to subjective differences between analysts. Recently it was demonstrated that artificial neural networks could be used to classify information within an electropherogram as allelic (i.e. representative of a DNA fragment present in the DNA extract) or as one of several different categories of artefactual fluorescence that arise as a result of generating an electropherogram. We extend that work here to demonstrate a series of algorithms and artificial neural networks that can be used to identify peaks on an electropherogram and classify them. We demonstrate the functioning of the system on several profiles and compare the results to a leading commercial DNA profile reading system.