Non-functional regression : A new challenge for neural networks
- Authors: Vamplew, Peter , Dazeley, Richard , Foale, Cameron , Choudhury, Tanveer
- Date: 2018
- Type: Text , Journal article
- Relation: Neurocomputing Vol. 314, no. (2018), p. 326-335
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- Description: This work identifies an important, previously unaddressed issue for regression based on neural networks – learning to accurately approximate problems where the output is not a function of the input (i.e. where the number of outputs required varies across input space). Such non-functional regression problems arise in a number of applications, and can not be adequately handled by existing neural network algorithms. To demonstrate the benefits possible from directly addressing non-functional regression, this paper proposes the first neural algorithm to do so – an extension of the Resource Allocating Network (RAN) which adds additional output neurons to the network structure during training. This new algorithm, called the Resource Allocating Network with Varying Output Cardinality (RANVOC), is demonstrated to be capable of learning to perform non-functional regression, on both artificially constructed data and also on the real-world task of specifying parameter settings for a plasma-spray process. Importantly RANVOC is shown to outperform not just the original RAN algorithm, but also the best possible error rates achievable by any functional form of regression.
Adaptive weighted non-parametric background model for efficient video coding
- Authors: Chakraborty, Subrata , Paul, Manoranjan , Murshed, Manzur , Ali, Mortuza
- Date: 2017
- Type: Text , Journal article
- Relation: Neurocomputing Vol. 226, no. (2017), p. 35-45
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- Description: Dynamic background frame based video coding using mixture of Gaussian (MoG) based background modelling has achieved better rate distortion performance compared to the H.264 standard. However, they suffer from high computation time, low coding efficiency for dynamic videos, and prior knowledge requirement of video content. In this paper, we introduce the application of the non-parametric (NP) background modelling approach for video coding domain. We present a novel background modelling technique, called weighted non-parametric (WNP) which balances the historical trend and the recent value of the pixel intensities adaptively based on the content and characteristics of any particular video. WNP is successfully embedded into the latest HEVC video coding standard for better rate-distortion performance. Moreover, a novel scene adaptive non-parametric (SANP) technique is also developed to handle video sequences with high dynamic background. Being non-parametric, the proposed techniques naturally exhibit superior performance in dynamic background modelling without a priori knowledge of video data distribution.
Softmax exploration strategies for multiobjective reinforcement learning
- Authors: Vamplew, Peter , Dazeley, Richard , Foale, Cameron
- Date: 2017
- Type: Text , Journal article
- Relation: Neurocomputing Vol. 263, no. (2017), p. 74-86
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- Description: Despite growing interest over recent years in applying reinforcement learning to multiobjective problems, there has been little research into the applicability and effectiveness of exploration strategies within the multiobjective context. This work considers several widely-used approaches to exploration from the single-objective reinforcement learning literature, and examines their incorporation into multiobjective Q-learning. In particular this paper proposes two novel approaches which extend the softmax operator to work with vector-valued rewards. The performance of these exploration strategies is evaluated across a set of benchmark environments. Issues arising from the multiobjective formulation of these benchmarks which impact on the performance of the exploration strategies are identified. It is shown that of the techniques considered, the combination of the novel softmax–epsilon exploration with optimistic initialisation provides the most effective trade-off between exploration and exploitation.
Steering approaches to Pareto-optimal multiobjective reinforcement learning
- Authors: Vamplew, Peter , Issabekov, Rustam , Dazeley, Richard , Foale, Cameron , Berry, Adam , Moore, Tim , Creighton, Douglas
- Date: 2017
- Type: Text , Journal article
- Relation: Neurocomputing Vol. 263, no. (2017), p. 26-38
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- Description: For reinforcement learning tasks with multiple objectives, it may be advantageous to learn stochastic or non-stationary policies. This paper investigates two novel algorithms for learning non-stationary policies which produce Pareto-optimal behaviour (w-steering and Q-steering), by extending prior work based on the concept of geometric steering. Empirical results demonstrate that both new algorithms offer substantial performance improvements over stationary deterministic policies, while Q-steering significantly outperforms w-steering when the agent has no information about recurrent states within the environment. It is further demonstrated that Q-steering can be used interactively by providing a human decision-maker with a visualisation of the Pareto front and allowing them to adjust the agent’s target point during learning. To demonstrate broader applicability, the use of Q-steering in combination with function approximation is also illustrated on a task involving control of local battery storage for a residential solar power system.
Discrete state transition algorithm for unconstrained integer optimization problems
- Authors: Zhou, Xiaojun , Gao, David , Yang, Chunhua , Gui, Weihua
- Date: 2016
- Type: Text , Journal article
- Relation: Neurocomputing Vol. 173, no. (2016), p. 864-874
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- Description: A recently new intelligent optimization algorithm called discrete state transition algorithm is considered in this study, for solving unconstrained integer optimization problems. Firstly, some key elements for discrete state transition algorithm are summarized to guide its well development. Several intelligent operators are designed for local exploitation and global exploration. Then, a dynamic adjustment strategy "risk and restoration in probability" is proposed to capture global solutions with high probability. Finally, numerical experiments are carried out to test the performance of the proposed algorithm compared with other heuristics, and they show that the similar intelligent operators can be applied to ranging from traveling salesman problem, boolean integer programming, to discrete value selection problem, which indicates the adaptability and flexibility of the proposed intelligent elements. (C) 2015 Elsevier B.V. All rights reserved.
Visual perceptual and handwriting skills in children with developmental coordination disorder
- Authors: Prunty, Mellissa , Barnett, Anna , Wilmut, Kate , Plumb, Mandy
- Date: 2016
- Type: Text , Journal article
- Relation: Human Movement Science Vol. 49, no. (2016), p. 54-65
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- Description: Objective: Children with Developmental Coordination Disorder demonstrate a lack of automaticity in handwriting as measured by pauses during writing. Deficits in visual perception have been proposed in the literature as underlying mechanisms of handwriting difficulties in children with DCD. The aim of this study was to examine whether correlations exist between measures of visual perception and visual motor integration with measures of the handwriting product and process in children with DCD. Method: The performance of twenty-eight 8-14 year-old children who met the DSM-5 criteria for DCD was compared with 28 typically developing (TD) age and gender-matched controls. The children completed the Developmental Test of Visual Motor Integration (VMI) and the Test of Visual Perceptual Skills (TVPS). Group comparisons were made, correlations were conducted between the visual perceptual measures and handwriting measures and the sensitivity and specificity examined. Results: The DCD group performed below the TD group on the VMI and TVPS. There were no significant correlations between the VMI or TVPS and any of the handwriting measures in the DCD group. In addition, both tests demonstrated low sensitivity. Conclusion: Clinicians should execute caution in using visual perceptual measures to inform them about handwriting skill in children with DCD. © 2016 The Authors.
A novel motion classification based intermode selection strategy for HEVC performance improvement
- Authors: Podder, Pallab , Paul, Manoranjan , Murshed, Manzur
- Date: 2015
- Type: Text , Journal article
- Relation: Neurocomputing Vol. 173, no. Part 3 (2015), p. 1211-1220
- Relation: http://purl.org/au-research/grants/arc/DP130103670
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- Description: High Efficiency Video Coding (HEVC) standard adopts several new approaches to achieve higher coding efficiency (approximately 50% bit-rate reduction) compared to its predecessor H.264/AVC with same perceptual image quality. Huge computational time has also increased due to the algorithmic complexity of HEVC compared to H.264/AVC. However, it is really a demanding task to reduce the encoding time while preserving the similar quality of the video sequences. In this paper, we propose a novel efficient intermode selection technique and incorporate into HEVC framework to predict motion estimation and motion compensation modes between current and reference blocks and perform faster inter mode selection based on three dissimilar motion types in divergent video sequences. Instead of exploring and traversing all the modes exhaustively, we merely select a subset of candidate modes and the final mode from the selected subset is determined based on their lowest Lagrangian cost function. The experimental results reveal that average encoding time can be downscaled by 40% with similar rate-distortion performance compared to the exhaustive mode selection strategy in HEVC.
- Description: High Efficiency Video Coding (HEVC) standard adopts several new approaches to achieve higher coding efficiency (approximately 50% bit-rate reduction) compared to its predecessor H.264/AVC with same perceptual image quality. Huge computational time has also increased due to the algorithmic complexity of HEVC compared to H.264/AVC. However, it is really a demanding task to reduce the encoding time while preserving the similar quality of the video sequences. In this paper, we propose a novel efficient intermode selection technique and incorporate into HEVC framework to predict motion estimation and motion compensation modes between current and reference blocks and perform faster inter mode selection based on three dissimilar motion types in divergent video sequences. Instead of exploring and traversing all the modes exhaustively, we merely select a subset of candidate modes and the final mode from the selected subset is determined based on their lowest Lagrangian cost function. The experimental results reveal that average encoding time can be downscaled by 40% with similar rate-distortion performance compared to the exhaustive mode selection strategy in HEVC. © 2015 Elsevier B.V.
From zero to hero. A case study of industrial injury reduction : New Zealand Aluminium Smelters Limited
- Authors: Young, Stephen
- Date: 2014
- Type: Text , Journal article
- Relation: Safety Science Vol. 64, no. (2014), p. 99-108
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- Description: There is a need to pursue more evidence to support the zero accident vision (ZAV). New Zealand Aluminium Smelters Limited (NZAS) has been operating under a ZAV for more than two decades and now consistently has fewer than ten lost-time injuries (LTI) per annum. While the ZAV has not been fully realised, NZAS is now one of the safest heavy industrial worksites in the world. This mixed method case study substantiates the significant reduction in LTIs and describes the interventions used to achieve the improvement. The interventions are rated using a hazard intervention effectiveness matrix and by contextualising their apparent efficacy within the available literature. The NZAS ZAV achievement is further analysed using goal theory. The study concludes by attributing NZAS' relative success to an assiduous application of hierarchy of control methodology with a particularly strong ergonomic focus. © 2013.
A HMM-based adaptive fuzzy inference system for stock market forecasting
- Authors: Hassan, Md Rafiul , Ramamohanarao, Kotagiri , Kamruzzaman, Joarder , Rahman, Mustafizur , Hossain, Maruf
- Date: 2013
- Type: Text , Journal article
- Relation: Neurocomputing Vol. 104, no. (2013), p. 10-25
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- Description: In this paper, we propose a new type of adaptive fuzzy inference system with a view to achieve improved performance for forecasting nonlinear time series data by dynamically adapting the fuzzy rules with arrival of new data. The structure of the fuzzy model utilized in the proposed system is developed based on the log-likelihood value of each data vector generated by a trained Hidden Markov Model. As part of its adaptation process, our system checks and computes the parameter values and generates new fuzzy rules as required, in response to new observations for obtaining better performance. In addition, it can also identify the most appropriate fuzzy rule in the system that covers the new data; and thus requires to adapt the parameters of the corresponding rule only, while keeping the rest of the model unchanged. This intelligent adaptive behavior enables our adaptive fuzzy inference system (FIS) to outperform standard FISs. We evaluate the performance of the proposed approach for forecasting stock price indices. The experimental results demonstrate that our approach can predict a number of stock indices, e.g., Dow Jones Industrial (DJI) index, NASDAQ index, Standard and Poor500 (S&P500) index and few other indices from UK (FTSE100), Germany (DAX) , Australia (AORD) and Japan (NIKKEI) stock markets, accurately compared with other existing computational and statistical methods.
Design of synthetic impact response functions for flood vulnerability assessment under climate change conditions: case studies in two selected coastal zones in Australia and Japan
- Authors: Dutta, Dushmanta , Wright, Wendy , Nakayama, Keisuke , Sugawara, Yohei
- Date: 2013
- Type: Text , Journal article
- Relation: Natural Hazards Review Vol. 14, no. 1 (2013), p. 52-65
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- Description: Sustainable coastal zone management strategies are imperative to avoid extreme social upheaval in both developing and developed countries. There is an increasing concern that the current management practices for many coastal regions are unsustainable under changing environmental and climate conditions. Sea level rise is of particular concern in coastal regions, and few countries have planned to deal with the exacerbation of environmental decline in the face of sea level rise. It is therefore necessary to assess socioeconomic and environmental impacts of sea level rises to better understand the vulnerability of the coastal zones, as part of devising adaptive and integrated management principles. This paper presents a systematic approach in which relevant stakeholders in Australia and Japan were actively engaged in identifying and prioritizing issues relating to the impacts of inundation and reduced water quality associated with flooding. The extent to which these issues are likely to be affected by flooding is quantified using synthetic response functions, and the key issues of concern for flood impacts for coastal areas in Australia and Japan are compared. Synthetic response functions as developed in this study can be used to quantify the likely impacts of flood hazards of various magnitude
Safety regulation: The lessons of workplace safety rule management for managing the regulatory burden
- Authors: Hale, Andrew , Borys, David , Adams, Mark
- Date: 2013
- Type: Text , Journal article
- Relation: Safety Science Vol. , no. (2013), p.
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- Description: There is a strong political consensus in a number of countries that occupational safety and health regulation is stifling industrial innovation and development and is feeding a culture of damaging risk aversion and petty bureaucracy. In a number of countries this has led to proposals to repeal regulations and reduce the regulatory burden. The authors were commissioned to prepare a discussion paper on this issue by the Mercatus Center of George Mason University in Arlington, Virginia, aimed particularly at an American audience. This paper is based on that report (Hale et al., 2011). The paper is based on previous work of the first two authors, developing a framework of occupational safety rule management at the workplace level (Hale and Borys, 2012a,b). Based on a literature study, this paper analyses the similarities and differences between rules at the workplace level and the development, use and enforcement of regulations at the national level to influence and control organisational behavior. It traces the forces encouraging the growth of regulatory detail and hence the bureaucratic burden of compliance and the options open to reduce that burden without loosening control so much that the level of safety declines. The analysis uses the hierarchy of rules from goals, through process (risk management) rules to detailed action rules as framework for predicting the level of ownership and responsibility felt by the regulated.
- Description: C1
Understanding safety management system applicability in community sport
- Authors: Donaldson, Alex , Borys, David , Finch, Caroline
- Date: 2013
- Type: Text , Journal article
- Relation: Safety Science Vol. 60, no. (2013), p. 95-104
- Relation: http://purl.org/au-research/grants/nhmrc/565907
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- Description: Despite recent interest in understanding the implementation context for sports injury prevention interventions, little research attention has been paid to the management structures and processes of community sporting organisations. This study developed expert consensus about the importance of Occupational Health and Safety (OHS) setting-related safety management system (SMS) principles and performance indicators in the context of Australian community sporting organizations, and the feasibility of these organisations meeting the requirements for the SMS performance indicators. Twenty-nine sports injury prevention, community sports administration and OHS SMS experts participated in a three-round online Delphi study by rating the importance of 64 SMS performance indicators categorised under the five principles of Commitment and Policy; Planning; Implementation; Measurement and Evaluation; and Review and Improvement. Overall, consensus agreement - define as rated 'essential' or 'very important' on a five-point scale by ≥75% of the participants in Round 3 - was reached for 57 performance indicators. Ten (15%) performance indicators were rated as 'very difficult' or 'relatively difficult', and six (9%) were rated as 'very easy' or 'relatively easy' on a four-point scale, by ≥75% of participants. This research suggests that the guiding principles and associated performance indicators that underpin OHS safety management systems in the workplace are very relevant and applicable to community sporting organisations in Australia. However, considerable work is required to build organisational capacity to be able to develop and implement meaningfully and useful SMSs to prevent sports injuries in the most common setting in which they occur. © 2013 Elsevier Ltd. Funded by NHMRC.
- Description: 2003011206
K-complex detection using a hybrid-synergic machine learning method
- Authors: Vu, Huy Quan , Li, Gang , Sukhorukova, Nadezda , Beliakov, Gleb , Liu, Shaowu , Philippe, Carole , Amiel, Hélène , Ugon, Adrien
- Date: 2012
- Type: Text , Journal article
- Relation: IEEE Transactions on Systems, Man and Cybernetics Part C : Applications and Reviews Vol. 42, no. 6 (2012), p. 1478-1490
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- Description: Sleep stage identification is the first step in modern sleep disorder diagnostics process. K-complex is an indicator for the sleep stage 2. However, due to the ambiguity of the translation of the medical standards into a computer-based procedure, reliability of automated K-complex detection from the EEG wave is still far from expectation. More specifically, there are some significant barriers to the research of automatic K-complex detection. First, there is no adequate description of K-complex that makes it difficult to develop automatic detection algorithm. Second, human experts only provided the label for whether a whole EEG segment contains K-complex or not, rather than individual labels for each subsegment. These barriers render most pattern recognition algorithms inapplicable in detecting K-complex. In this paper, we attempt to address these two challenges, by designing a new feature extraction method that can transform visual features of the EEG wave with any length into mathematical representation and proposing a hybrid-synergic machine learning method to build a K-complex classifier. The tenfold cross-validation results indicate that both the accuracy and the precision of this proposed model are at least as good as a human expert in K-complex detection. © 1998-2012 IEEE.
- Description: 2003010569
Working to rule or working safely? Part 2 : The management of safety rules and procedures
- Authors: Hale, Andrew , Borys, David
- Date: 2012
- Type: Text , Journal article
- Relation: Safety Science Vol.55, no. (2012), p.54-59
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- Description: Part 1, the companion paper to this paper () reviews the literature from 1986 on the management of those safety rules and procedures which relate to the workplace level in organisations. It contrasts two different paradigms of how work rules and their development and use are perceived and managed. The first is a top-down classical, rational approach in which rules are seen as static, comprehensive limits of freedom of choice, imposed on operators at the sharp end and violations are seen as negative behaviour to be suppressed. The second is a bottom-up constructivist view of rules as dynamic, local, situated constructions of operators as experts, where competence is seen to a great extent as the ability to adapt rules to the diversity of reality. That paper explores the research underlying and illustrating these two paradigms. In this second paper we draw on that literature study to propose a framework of rule management which attempts to draw the lessons from both paradigms. It places the monitoring and adaptation of rules central to its management process and emphasises the need for participation of the intended rule followers in the processes of rule-making, but more importantly in keeping those rules alive and up to date in a process of regular and explicit dialogue with first-line supervision, and through them with the technical, safety and legal experts on the system functioning. The framework is proposed for testing in the field as a benchmark for good practice. © 2012 Elsevier Ltd. All rights reserved.
Working to rule, or working safely? Part 1 : A state of the art review
- Authors: Hale, Andrew , Borys, David
- Date: 2012
- Type: Text , Journal article
- Relation: Safety Science Vol.55, no. June (2013), p.207-221
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- Description: The paper reviews the literature from 1986 on the management of those safety rules and procedures which relate to the workplace level in organisations. It contrasts two different paradigms of how rules and their development and use are perceived and managed. The first is a top-down classical, rational approach in which rules are seen as static, comprehensive limits of freedom of choice, imposed on operators at the sharp end and violations are seen as negative behaviour to be suppressed. The second is a bottom-up constructivist view of rules as dynamic, local, situated constructions of operators as experts, where competence is seen to a great extent as the ability to adapt rules to the diversity of reality. The paper explores the research underlying and illustrating these two paradigms, drawn from psychology, sociology and ethnography, organisational studies and behavioural economics. In a separate paper following on from this review (Hale and Borys, this issue http://www.sciencedirect.com/science/article/pii/S0925753512001312#b0285) the authors propose a framework of rule management which attempts to draw the lessons from both paradigms. It places the monitoring and adaptation of rules central to its management process. © 2012 Elsevier Ltd. All rights reserved.
Attitude and behaviour of junior rugby union players towards tackling during training and match play
- Authors: Finch, Caroline
- Date: 2011
- Type: Text , Journal article
- Relation: Safety Science Vol. 50, no. 4 (April 2012), p. 1157
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Constrained action selection in children with developmental coordination disorder
- Authors: Pettit, Lewis , Charles, Jennifer , Wilson, Andrew , Plumb, Mandy , Brockman, Anne , Williams, Justin , Mon-Williams, Mark
- Date: 2008
- Type: Text , Journal article
- Relation: Human Movement Science Vol. 27, no. 2 (2008), p. 286-295
- Full Text: false
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- Description: The effect of advance ('precue') information on short aiming movements was explored in adults, high school children, and primary school children with and without developmental coordination disorder (n=10, 14, 16, 10, respectively). Reaction times in the DCD group were longer than in the other groups and were more influenced by the extent to which the precue constrained the possible action space. In contrast, reaction time did not alter as a function of precue condition in adults. Children with DCD showed greater inaccuracy of response (despite the increased RT). We suggest that the different precue effects reflect differences in the relative benefits of priming an action prior to definitive information about the movement goal. The benefits are an interacting function of the task and the skill level of the individual. Our experiment shows that children with DCD gain a benefit from advance preparation in simple aiming movements, highlighting their low skill levels. This result suggests that goal-directed RTs may have diagnostic potential within the clinic.
Online corrections in children with and without DCD
- Authors: Plumb, Mandy , Wilson, Andrew , Mulroue, Amy , Brockman, Anne , Williams, Justin , Mon-Williams, Mark
- Date: 2008
- Type: Text , Journal article
- Relation: Human Movement Science Vol. 27, no. 5 (2008), p. 695-704
- Full Text: false
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- Description: Human arm movements need 'online' corrections due to noise in perception and action. A Step-Perturbation paradigm explored online corrections in control children and children with DCD aged between 7 and 13 years. Control children found the task straightforward: a distracter had no effect and they managed to stop relatively quickly. Children with DCD found the task difficult and the apparatus was modified accordingly (decreased postural and force production demands). The distracter affected some children with DCD and some found it difficult to stop. All of the DCD population showed poorer performance in both the perturbation and non-perturbation condition. Nevertheless, there was no interaction between group and condition. Thus, this study found no evidence for specific deficits in online correction mechanisms in DCD. We suggest that: (i) fundamental problems in generating basic movements can account for the documented difficulties in correcting on-going movements, and (ii) such fundamental difficulties make it very difficult to pinpoint specific mechanism deficits.
Galvanic and acoustic vestibular stimulation activate different populations of vestibular afferents
- Authors: Bacsi, Ann M , Watson, Shaun , Colebatch, James G
- Date: 2003
- Type: Text , Journal article
- Relation: Clinical Neurophysiology Vol. 114, no. 2 (2003), p. 359-365
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- Description: OBJECTIVE: To deduce whether similar or distinct populations of vestibular afferents are activated by acoustic and galvanic vestibular stimulation by comparing the effectiveness of 'matched' stimuli in eliciting vestibulospinal reflexes. METHODS: Twelve subjects (5 men, 7 women) underwent individual 'matching' of 2 ms tone burst and galvanic stimuli, using vestibulocollic reflexes so that corrected reflex amplitudes to tone burst and galvanic stimuli were within 10% of each other. These same intensities were then administered using 20 ms durations to determine whether they were equally effective in evoking vestibulospinal responses. RESULTS: Corrected reflex amplitudes for vestibulocollic responses to tone burst and galvanic stimulation were not significantly different for the right (P=0.45) or left (P=0.68) sides. All subjects had vestibulospinal responses to galvanic stimulation (average intensity 4.0 mA for both sides). The short latency (SL) and medium latency (ML) components of the vestibulospinal reflexes were larger after galvanic compared to tone burst stimulation in 11 of 12 subjects (P<0.01). CONCLUSIONS: Despite evoking equal-sized vestibulocollic reflexes, there was a clear dissociation between the magnitude of tone burst and galvanic-induced vestibulospinal reflexes. Galvanic stimulation evoked SL and ML reflexes in all subjects. Tone burst stimuli evoked only small SL reflexes and, in most cases, no ML reflexes. Acoustically-evoked vestibulocollic reflexes are likely to be due to saccular excitation. The limited effectiveness of longer tone burst stimuli to evoke ML vestibulospinal reflexes suggests that saccular afferents have, at most, only a minor role in the production of these reflexes. We conclude that galvanic stimulation is more effective in eliciting vestibulospinal reflexes than tone burst stimulation, and that the two methods activate different populations of vestibular afferents.