389 research outputs found
A Case Study on Parent-Child Interactions in Japanese Family Picture Book Reading Activities : Transformation of Picture Book Questions
This paper studies how textual questions in picture books are transformed into relevant questions in the process of storytelling by the parents. By looking at two examples from a dataset of picture book reading conversations, this analysis reveals how Japanese parents incorporate Japanese linguistic structures, embodied resources, and physical materials from picture books into their own actions, through which they easily engage children in reading activities and enhance their understanding
Anomaly Identification Model for Telecom Users Based on Machine Learning Model Fusion
With the development of economic globalization and modern information and communication technology, the situation of communication fraud is becoming more and more serious. How to identify fraudulent calls accurately and effectively has become an urgent task in current telecommunications operations. Affected by the sample set and the current state of the art, the current machine learning methods used to identify the imbalanced distribution dataset of positive and negative samples have low recognition accuracy. Therefore, in this paper, we propose a new hybrid model solution that uses feature construction, feature selection and imbalanced classes handling. A stacking model fusion algorithm composed of a two-layer stacking framework with several state-of-the-art machine learning classifiers is adopted. The results show that the risk user identification model based on mobile network communication behavior established by our stacking model fusion algorithm can accurately predict the category labels of telecom users and improve the risk of telecom users. The generalization performance of the identification is high, which provides a certain reference for the telecommunications industry to identify risk users based on mobile network communication behaviors
Flamelet modelling in fire-relevant conditions
Accurate predictions of fire dynamics lead to improved mitigation of life and property losses. However, challenges remain due to the complex interaction of buoyancy-driven turbulence, chemical reaction and radiation in fires. Simplified combustion models that solve a global combustion equation have been widely applied in previous numerical simulations of fires to reduce computational costs. These simplified modelling approaches are unable to accurately predict complicated phenomena such as extinction that are strongly dependent on detailed chemical kinetics, which impacts their contribution to fire safety and mitigation strategies. Flamelet modelling is a promising combustion model to account for detailed chemistry at a relatively low cost and hence has a great potential to improve the predictability of numerical simulations in fires. While flamelet modelling has been widely investigated for flames in energy applications, there are limited studies of their performance in fire conditions which involve strong interactions between turbulence, chemistry and radiation. To address this, simulations and analyses of flamelet-based models in fire-relevant conditions are conducted in this thesis. Firstly, different methods to incorporate radiation in flamelet models are evaluated in an a priori study using detailed simulations of a laminar methane-air diffusion flame with various optical thicknesses. It is revealed that a new Lagrangian radiative flamelet method proposed in this work, which ensures a consistent treatment for the radiation absorption between the computational fluid dynamics (CFD) simulations in physical space and the flamelet equation in mixture fraction space, provides improved results compared to other widely applied Eulerian radiative flamelet methods. Subsequently, large eddy simulations (LES) of turbulent line fires with varying ventilation conditions are conducted using two sets of tabulation variables for the flamelet library. A significant flame-weakening effect is induced by local extinction in strongly under-ventilated conditions, which is only captured by the unsteady radiative flamelet/progress variable (URFPV) approach. The URFPV model is then used to study the turbulence-radiation interaction (TRI) in turbulent line fires, where the subgrid-scale (SGS) TRI is modelled by a presumed filtered density function method. It is found that local extinction leads to an increased contribution of the SGS emission TRI in LES of fires
Travellers' attitudes towards Park-and-Ride (PnR) and choice of PnR station: Evidence from Perth, Western Australia
An attractive transport alternative that combines the efficiency of public transport with the flexibility of cars, with the potential to reduce traffic congestion and become integral part of the transit-oriented developments, PnR received much interest in the last decade. This is particularly relevant to Australian urban landscape and especially Perth, where the low urban density means thatmore than 90% of residents live outside of 800 m distance from train stations. Drawing on an intercept survey, we identified PnR and basic facilities within the station perimeter as key differentiating factors of access and service across rail corridors. Then, using discrete choice models we found that paid parking bays, bike lockers, access mode and time-of-day were the most influential in determining the choice of train station, more so than the distance. Notably, there were two classes of travellers, one seeking stations with good facilities, and the other being more interested in quick access to the station
Comparison of perceived and measured accessibility between different age groups and travel modes at Greenwood Station, Perth, Australia
Although there has been a significant focus on evaluating accessibility to facilities, the differences between age groups and/or mode of access to train stations is less clear. This paper compares perceived and measured accessibility to train stations among three age groups: young adults (18-24), middle aged adults (25-59) and elderly adults (60+) and three travel modes, Park and Ride (PnR), Bus and Ride (BnR) and Walk and Ride (WnR). The study focuses on the Greenwood railway station, Perth, Australia. Measured accessibility was lower than perceived accessibility for all three age groups. Both perceived and measured accessibility to train stations were lower for the elderly than the other groups. The catchment area of elderly PnR users was also the smallest. Middle aged adults evaluated accessibility (perceived) by WnR the highest. Young adults were found to have a larger PnR catchment area than other groups. Inadequate accessibility to Greenwood Station for different age groups and by different travel modes were identified, which can be used as a decision-making aid by practitioners and station managers for improving accessibility for these cohorts. The techniques used are directly transferable to the study of other stations
Rank the spreading influence of nodes using dynamic Markov process
Ranking the spreading influence of nodes is of great importance in practice and research. The key to ranking a node’s spreading ability is to evaluate the fraction of susceptible nodes being infected by the target node during the outbreak, i.e. the outbreak size. In this paper, we present a dynamic Markov process (DMP) method by integrating the Markov chain and the spreading process to evaluate the outbreak size of the initial spreader. Following the idea of the Markov process, this method solves the problem of nonlinear coupling by adjusting the state transition matrix and evaluating the probability of the susceptible node being infected by its infected neighbors. We have employed the susceptible-infected-recovered and susceptible-infected-susceptible models to test this method on real-world static and temporal networks. Our results indicate that the DMP method could evaluate the nodes’ outbreak sizes more accurately than previous methods for both single and multi-spreaders. Besides, it can also be employed to rank the influence of nodes accurately during the spreading process
Single Nucleotide Polymorphisms of MicroRNA Processing Machinery Genes and Outcome of Hepatocellular Carcinoma
MicroRNA (miRNA)-related single nucleotide polymorphisms (miR-SNPs) can affect cancer development, treatment efficacy and patients prognosis. We examined 6 miR-SNPs in miRNA processing machinery genes including exportin 5 (XPO5) (rs11077), Ran-GTPase (RAN) (rs14035), Dicer (rs3742330), Trinucleotide Repeat Containing 6B (TNRC6B) (rs9623117), GEMIN3 (rs197412), GEMIN4 (rs2740348) in 108 surgically resected HCC patients and evaluated the impact of these miR-SNPs on HCC outcome. Among the 6 SNPs, only the A/A genotype of rs11077 located in XPO5 3′UTR was identified to associated independently with worse survival in HCC patients by multivariate analysis with relative risk, 0.395; 95% CI, 0.167–0.933; p = 0.034. This is the first study reporting that polymorphisms related to miRSNPs have prognostic value in hepatocellular carcinoma and identify the A/A genotype of rs11077 SNP site located in XPO5 3′UTR can help to predict worse prognosis in patients
Enhanced Huff Model for Estimating Park and Ride (PnR) Catchment Areas in Perth, WA
A train station catchment area delineates the spatial territory from which the users of a train station are drawn. The size and shape of this catchment can be influenced by a variety of factors, such as the transport network, the location of stations and the service quality they offer, as well as the land use density and diversity in the transport corridor. Although numerous studies have been conducted to understand the size of catchment areas, limited research has focused on determining the spatial boundary (shape) of train station catchments. This paper develops a framework for deriving a spatial boundary of a Park and Ride (PnR) catchment area by incorporating the Huff model and Geographic Information Systems (GIS) technologies. The approach is staged, firstly determining the PnR station choice as a function of the attractiveness of a train station and the cost of access between the origin (such as a suburb) and the destination of a trip (such as the Perth CBD). Linear referencing method is then applied to re-define the origins to train stations based on the derived station choice probability. Finally, the spatial boundary of a catchment area is determined according to the adjusted origins, using GIS technologies. The model outputs were evaluated against licence plate survey of station users, where the Kappa coefficient (0.74) and overall accuracy (0.88) statistic suggested that the model's results are robust. The paper then shows how catchment area data can be used to better manage travel demand and plan design solutions aimed at increased accessibility to train stations
Generalized invariance principles for stochastic dynamical systems and their applications
Investigating long-term behaviors of stochastic dynamical systems often requires to establish criteria that are able to describe delicate dynamics of the considered systems. In this article, we develop generalized invariance principles for continuous-time stochastic dynamical systems. Particularly, in a sense of probability one and by the developed semimartingale convergence theorem, we not only establish a local invariance principle, but also provide a generalized global invariance principle that allows the sign of the diffusion operator to be positive in some bounded region. We further provide an estimation for the time when a trajectory, initiating outside a particular bounded set, eventually enters it. Finally, we use several representative examples, including stochastic oscillating dynamics, to illustrate the practical usefulness of our analytical criteria in deciphering the stabilization or/and the synchronization dynamics of stochastic systems
Spatial analysis of access to and accessibility to surrounding train stations: a case study of accessibility for the elderly in Perth, Western Australia
Approximately one-fifth of Perth’s population is aged 60 or older. Projections suggest that this proportion will continue to increase as a result of the large number of children born after the World War II (1946–1964). Access to and accessibility around train stations for the aging population is and will become a more important issue as the elderly population continues to grow. The aim of the paper is to develop and apply anew measure of accessibility to train stations at a fine spatial scale, justified by the special circumstance of the elderly using a case study in Perth, Western Australia. Intercept surveys are used to collect data on factors affecting train station accessibility for patrons aged 60 years or older, at seven highly dispersed train stations. Overall accessibility is measured separately using a composite index based on three travel modes (walk-and-ride, park-and-ride and bus-and-ride). The results illustrate that key variables, such as distance from an origin to a station, walking or driving route directness, land-use diversity, service and facility quality, bus connection to train stations, all affect the accessibility to train stations for the elderly. This implies that improvements to these factors will improve accessibility for this population group
- …