A syntactic two-component encoding model for the trajectories of human actions

Human actions have been widely studied for their potential application in various areas such as sports, pervasive patient monitoring, and rehabilitation. However, challenges still persist pertaining to determining the most useful ways to describe human actions at the sensor, then limb and complete action levels of representation and deriving important relations between these levels each involving their own atomic components. In this paper, we report on a motion encoder developed for the sensor level based on the need to distinguish between the shape of the sensor's trajectory and its temporal characteristics during execution. This distinction is critical as it provides a different encoding scheme than the usual velocity and acceleration measures which confound these two attributes of any motion. At the same time, we eliminate noise from sensors by comparing temporal and spatial indexing schemes and a number of optimal filtering models for robust encoding. Results demonstrate the benefits of spatial indexing and separating the shape and dynamics of a motion, as well as its ability to decompose complex motions into several atomic ones. Finally, we discuss how this specific type of sensor encoder bears on the derivation of limb and complete action descriptions.

Cost-effectiveness analysis of a two-stage screening intervention for hepatocellular carcinoma in Taiwan

Background/Purpose

Hepatocellular carcinoma (HCC) has been the leading cause of cancer death in Taiwan since the 1980s. A two-stage screening intervention was introduced in 1996 and has been implemented in a limited number of hospitals. The present study assessed the costs and health outcomes associated with the introduction of screening intervention, from the perspective of the Taiwanese government. The cost-effectiveness analysis aimed to assist informed decision making by the health authority in Taiwan.
Methods

A two-phase economic model, 1-year decision analysis and a 60-year Markov simulation, was developed to conceptualize the screening intervention within current practice, and was compared with opportunistic screening alone. Incremental analyses were conducted to compare the incremental costs and outcomes associated with the introduction of the intervention. Sensitivity analyses were performed to investigate the uncertainties that surrounded the model.
Results

The Markov model simulation demonstrated an incremental cost-effectiveness ratio (ICER) of NT$498,000 (US$15,600) per life-year saved, with a 5% discount rate. An ICER of NT$402,000 (US$12,600) per quality-adjusted life-year was achieved by applying utility weights. Sensitivity analysis showed that excess mortality reduction of HCC by screening and HCC incidence rates were the most influential factors on the ICERs. Scenario analysis also indicated that expansion of the HCC screening intervention by focusing on regular monitoring of the high-risk individuals could achieve a more favorable result.
Conclusion

Screening the population of high-risk individuals for HCC with the two-stage screening intervention in Taiwan is considered potentially cost-effective compared with opportunistic screening in the target population of an HCC endemic area.

A state space based approach in non-linear hemodynamic response modeling with fMRI data

In this paper we use the modified and integrated version of the balloon model in the analysis of fMRI data. We propose a new state space model realization for this balloon model and represent it with the standard A,B,C and D matrices widely used in system theory. A second order Padé approximation with equal numerator and denominator degree is used for the time delay approximation in the modeling of the cerebral blood flow. The results obtained through numerical solutions showed that the new state space model realization is in close agreement to the actual modified and integrated version of the balloon model. This new system theoretic formulation is likely to open doors to a novel way of analyzing fMRI data with real time robust estimators. With further development and validation, the new model has the potential to devise a generalized measure to make a significant contribution to improve the diagnosis and treatment of clinical scenarios where the brain functioning get altered. Concepts from system theory can readily be used in the analysis of fMRI data and the subsequent synthesis of filters and estimators.

Human action recognition based on pyramid histogram of oriented gradients

Human action recognition has been attracted lots of interest from computer vision researchers due to its various promising applications. In this paper, we employ Pyramid Histogram of Orientation Gradient (PHOG) to characterize human figures for action recognition. Comparing to silhouette-based features, the PHOG descriptor does not require extraction of human silhouettes or contours. Two state-space models, i.e.; Hidden Markov Model (HMM) and Conditional Random Field (CRF), are adopted to model the dynamic human movement. The proposed PHOG descriptor and the state-space models with respect to different parameters are tested using a standard dataset. We also testify the robustness of the method with respect to various unconstrained conditions and viewpoints. Promising experimental result demonstrates the effectiveness and robustness of our proposed method.

CodePipe : an opportunistic feeding and routing protocol for reliable multicast with pipelined network coding

Multicast is an important mechanism in modern wireless networks and has attracted significant efforts to improve its performance with different metrics including throughput, delay, energy efficiency, etc. Traditionally, an ideal loss-free channel model is widely used to facilitate routing protocol design. However, the quality of wireless links would be affected or even jeopardized by many factors like collisions, fading or the noise of environment. In this paper, we propose a reliable multicast protocol, called CodePipe, with advanced performance in terms of energy-efficiency, throughput and fairness in lossy wireless networks. Built upon opportunistic routing and random linear network coding, CodePipe not only simplifies transmission coordination between nodes, but also improves the multicast throughput significantly by exploiting both intra-batch and inter-batch coding opportunities. In particular, four key techniques, namely, LP-based opportunistic routing structure, opportunistic feeding, fast batch moving and inter-batch coding, are proposed to offer substantial improvement in throughput, energy-efficiency and fairness. We evaluate CodePipe on ns2 simulator by comparing with other two state-of-art multicast protocols, MORE and Pacifier. Simulation results show that CodePipe significantly outperforms both of them.

Freshwater influences on hydrology and seagrass dynamics of intermittent estuaries

Many temperate estuaries have intermittently open and closed mouths, a feature that is often related to intermittent freshwater input. These systems, often overlooked due to their small size, can have large hydrological variability over medium-term time scales.

This variability presents potential difficulties for estuarine species particularly where anthropogenic alterations to freshwater flows can cause large deviations from natural patterns of tidal influence and inundation of habitat.

Influences of natural and hydrological variability on seagrasses were examined in two central Victorian estuaries with anthropogenically-modified but naturally-intermittent freshwater flows and mouth openings. Comparisons were focused on differences between an estuary with artificially-augmented freshwater inflow and an adjacent system, in which the volume and timing of inflows were altered by a reservoir. Eight additional estuaries in the region were also used to provide a context for these two main sites.

Hydrological changes during the three-year field component were affected by the ending of a drought and then a major flood a year later as well as by ongoing anthropogenic flow reduction and augmentation. These influences on hydrology were associated with an initially high seagrass coverage that was substantially reduced and showed signs of recovery only in the system that was affected by lower inflows. Such influences and responses also changed seasonally but to a much lesser extent than the responses to stochastic climatic events.

Natural flows were intermittent and varied substantially between years. Flooding flows represented up to 89% of the long-term annual average flow. Water quality was broadly typical of the region, with the exception of low pH in some tributaries, especially those of Anglesea estuary. Anthropogenic changes to flow were most evident at times of low natural flows and resulted in longer and more frequent periods of zero inflow to Painkalac estuary and a continual base flow to Anglesea. This base flow, from ponds containing coal ash, neutralised waters flowing from upstream and increased conductivity, except at times of high natural flow.

A three-state conceptual model of the magnitude and variability of water levels, based largely on the degree of tidal influence was identified and quantitatively assessed for the two estuaries that were the main focus of the study. These states in turn had a large influence on the area and inundation of benthic habitat. Floods tended to open the mouths of estuaries, which then remained tidal given sufficient flow to overcome sedimentary processes at the mouths. Low and zero inflow was a precondition for closure of the mouths of the estuaries. When closed, differences in inflow resulted in different endpoints in salinity patterns. From an initial pattern similar to a classic ‘salt wedge’, Painkalac estuary, with reduced inflow, quickly destratified and gradually became more saline, at times hypersaline. Anglesea estuary, with augmented flow, tended to remain stratified for longer until becoming completely fresh, given a long enough period of closure.

Episodic changes in the water quality of the estuaries were associated with different components of the freshwater flow regimes. At high flows, fresh waters of low pH with a high metal load entered Anglesea estuary. Except during the largest flood, when the estuary was completely flushed, this water was neutralised at the halocline and resulting in precipitation of metals. High flows into Painkalac were associated with elevated concentrations of clay-sourced suspended solids. During a closed period, with zero flow, a release of sediment-bound nutrients triggered by anoxia was observed in Painkalac, followed by an algal bloom.

The large decline in seagrass extent that was observed in both estuaries was closely related to floods and the subsequent reductions in potential habitat associated with the tidal states that followed. Analysis of historical patterns of extent against rainfall records suggested that periods of drought and extended mouth closures were related to establishment and expansion of beds. This model was similar to that described for South African estuaries and contrasted with more-seasonal patterns reported for local marine embayments.

Rates of in situ decomposition of seagrass detritus showed a mix of seasonal and disturbance-driven patterns of change, depending on estuary. Variability of these rates on a scale of 100s of metres was typically not significant, but there were a few episodes that were highly significant. A negative correlation between decomposition rate and seagrass extent was also observed. A novel technique for assessing cellulose decomposition potential in sediment, adapted from soil science, proved to be a useful tool for estuarine research. Results from this component of the study highlighted both small-scale variability that was inconsistent through time, and also stable differences in decomposition potential between depths and estuaries that were consistent with differences in hydrological state and salinity.

Given the relative lack of knowledge about processes in intermittent estuaries, particularly those relating to changes in freshwater inflow, results from this study will be of value both locally and for similar systems elsewhere. Locally, it is likely that flow regimes to both Anglesea and Painkalac estuaries will be reduced, following closure of the mine power station at Anglesea and due to increased demand from the reservoir above Painkalac. There is potential to manage flows from each of these sources to minimise downstream effects. Regionally, and globally, there are many intermittent estuaries in areas with Mediterranean-type climates. It has been predicted that the climates of these regions will become drier but with an increase in intensity of storm events, both of which have ramifications for flow regimes to estuaries. It is hoped that results of this study will contribute to more informed management of intermittent estuaries in the context of these likely changes.

Reliable multicast with pipelined network coding using opportunistic feeding and routing

Multicast is an important mechanism in modern wireless networks and has attracted significant efforts to improve its performance with different metrics including throughput, delay, energy efficiency, etc. Traditionally, an ideal loss-free channel model is widely used to facilitate routing protocol design. However, the quality of wireless links is affected or even jeopardized resulting in transmission failures by many factors like collisions, fading or the noise of environment. In this paper, we propose a reliable multicast protocol, called CodePipe, with energy-efficiency, high throughput and fairness in lossy wireless networks. Building upon opportunistic routing and random linear network coding, CodePipe can not only eliminate coordination between nodes, but also improve the multicast throughput significantly by exploiting both intra-batch and inter-batch coding opportunities. In particular, four key techniques, namely, LP-based opportunistic routing structure, opportunistic feeding, fast batch moving and inter-batch coding, are proposed to offer significant improvement in throughput, energy-efficiency and fairness.Moreover, we design an efficient online extension of CodePipe such that it can work in a dynamic network where nodes join and leave the network as time progresses. We evaluate CodePipe on ns2 simulator by comparing with other two state-of-art multicast protocols,MORE and Pacifier. Simulation results show that CodePipe significantly outperforms both of them.

A hybrid model of fuzzy ARTMAP and genetic algorithm for data classification and rule extraction

A two-stage hybrid model for data classification and rule extraction is proposed. The first stage uses a Fuzzy ARTMAP (FAM) classifier with Q-learning (known as QFAM) for incremental learning of data samples, while the second stage uses a Genetic Algorithm (GA) for rule extraction from QFAM. Given a new data sample, the resulting hybrid model, known as QFAM-GA, is able to provide prediction pertaining to the target class of the data sample as well as to give a fuzzy if-then rule to explain the prediction. To reduce the network complexity, a pruning scheme using Q-values is applied to reduce the number of prototypes generated by QFAM. A 'don't care' technique is employed to minimize the number of input features using the GA. A number of benchmark problems are used to evaluate the effectiveness of QFAM-GA in terms of test accuracy, noise tolerance, model complexity (number of rules and total rule length). The results are comparable, if not better, than many other models reported in the literature. The main significance of this research is a usable and useful intelligent model (i.e., QFAM-GA) for data classification in noisy conditions with the capability of yielding a set of explanatory rules with minimum antecedents. In addition, QFAM-GA is able to maximize accuracy and minimize model complexity simultaneously. The empirical outcome positively demonstrate the potential impact of QFAM-GA in the practical environment, i.e., providing an accurate prediction with a concise justification pertaining to the prediction to the domain users, therefore allowing domain users to adopt QFAM-GA as a useful decision support tool in assisting their decision-making processes.

The failures of neo-liberal state building in Iraq: assessing Australia's post-conflict reconstruction and development Initiatives

This article examines Australia's post-conflict reconstruction and development initiatives in Iraq following the intervention of 2003. Overall, it finds that Australia privileged the neo-liberal model of post-conflict state building by investing in projects that would enhance the capacity of the new Iraqi state, its key institutions and the private sector towards the imposition of a liberal democracy and a free-market economy. To demonstrate, this article documents the failures of the Australian government's stated aims to "support agriculture" and "support vulnerable populations" via interviews conducted in Iraq with rural farmers and tribal members and those working in, or the beneficiaries of, Iraq's disability sector. It concludes by noting that such failures are not only indicative of the inadequacy of the neo-liberal state building model, but also that these failures point the way forward for future post-conflict reconstruction and development projects which ought to be premised on a genuine and sustained commitment to addressing the needs of those made most vulnerable by war and regime change.

Concepts and dimensionality in modeling unsaturated water flow and solute transport

Many environmental studies require accurate simulation of water and solute fluxes in the unsaturated zone. This paper evaluates one- and multi-dimensional approaches for soil water flow as well as different spreading mechanisms to model solute behavior at different scales. For quantification of soil water fluxes,Richards equation has become the standard. Although current numerical codes show perfect water balances, the calculated soil water fluxes in case of head boundary conditions may depend largely on the method used for spatial averaging of the hydraulic conductivity. Atmospheric boundary conditions, especially in the case of phreatic groundwater levels fluctuating above and below a soil surface, require sophisticated solutions to ensure convergence. Concepts for flow in soils with macro pores and unstable wetting fronts are still in development. One-dimensional flow models are formulated to work with lumped parameters in order to account for the soil heterogeneity and preferential flow. They can be used at temporal and spatial scales that are of interest to water managers and policymakers. Multi-dimensional flow models are hampered by data and computation requirements.Their main strength is detailed analysis of typical multi-dimensional flow problems, including soil heterogeneity and preferential flow. Three physically based solute-transport concepts have been proposed to describe solute spreading during unsaturated flow: The stochastic-convective model (SCM), the convection-dispersion equation (CDE), and the fraction aladvection-dispersion equation (FADE). A less physical concept is the continuous-time random-walk process (CTRW). Of these, the SCM and the CDE are well established, and their strengths and weaknesses are identified. The FADE and the CTRW are more recent,and only a tentative strength weakness opportunity threat (SWOT)analysis can be presented at this time. We discuss the effect of the number of dimensions in a numerical model and the spacing between model nodes on solute spreading and the values of the solute-spreading parameters. In order to meet the increasing complexity of environmental problems, two approaches of model combination are used: Model integration and model coupling. Amain drawback of model integration is the complexity of there sulting code. Model coupling requires a systematic physical domain and model communication analysis. The setup and maintenance of a hydrologic framework for model coupling requires substantial resources, but on the other hand, contributions can be made by many research groups.

Sequential technology adoption with asymmetric firms

We analyse the incentives and welfare implications of costly technology adoption in a two-period duopoly model where firms have different amounts of capital. We also extend our framework to an open economy set-up and examine the relationship between trade and technology adoption. Our findings are as follows. First, no monotone relationship exists between the threshold cost of adoption and capital shares. Second, an unequal distribution of capital, despite lessening competition, can increase total surplus. Third, trade generally encourages adoption of modern technology unless the share of capital for the adopters is too low.

Latent structure of mentoring function scales

The latent structure of a 16-item mentoring function instrument was analyzed with the responses of 568 full-time employees. Features of the analyses included (a) assessment of the items' distributional properties (i.e., skewness and kurtosis); (b) assessment of the factor structure using the Satorra-Bentler scaled test statistic; and (c) evaluation of the instrument's invariance across sex. Confirmatory factor analyses using the scaled chi-square supported a two-factor oblique model that consisted of psychosocial and career-related mentoring functions. The invariance tests suggested that the structure was invariant across sex groups.

Credit risk of interest rate swaps : a comparative study of CIR and Monte Carlo simulation approach

This paper compares the credit risk profile for two types of model, the Monte Carlo model used in the existing literature, and the Cox, Ingersoll and Ross (CIR) model. Each of the profiles has a concave or hump-backed shape, reflecting the amortisation and diffusion effects. However, the CIR model generates significantly different results. In addition, we consider the sensitivity of these models of credit risk to initial interest rates, volatility, maturity, kappa and delta. The results show that the sensitivities vary across the models, and we explore the meaning of that variation.

Narrative structure analysis with education and training videos for e-learning

This paper deals with the problem ofstructuralizing education and training videos for high-level semantics extraction and nonlinear media presentation in e-learning applications. Drawing guidance from production knowledge in instructional media, we propose six main narrative structures employed in education and training videos for both motivation and demonstration during learning and practical training. We devise a powerful audiovisual feature set, accompanied by a hierarchical decision tree-based classification system to determine and discriminate between these structures. Based on a two-liered hierarchical model, we demonstrate that we can achieve an accuracy of 84.7% on a comprehensive set of education and training video data.

Comparing shape and temporal PDMs

The Point Distribution Model (PDM) has been successfully used in representing sets of static and moving images. A recent extension to the PDM for moving objects, the temporal PDM, has been proposed. This utilises quantities such as velocity and acceleration to more explicitly consider the characteristics of the movement and the sequencing of the changes in shape that occur. This research aims to compare the two types of model based on a series of arm movements, and to examine the characteristics of both approaches.