Providing RIA user interfaces with accessibility properties

Rich Internet Applications (RIAs) technologies are challenging the way in which the Web is being developed. However, from the UI accessibility point of view, these technologies pose new challenges that the Web Accessibility Initiative of the W3C is trying to solve through the use of a standard specification for Accessible Rich Internet Applications (WAI-ARIA). Currently, the introduction of properties defined in WAI-ARIA is being done in an ad-hoc manner due to the lack of models, methodologies and tools to support the design of accessible RIA UIs. In this paper we propose a semantic approach to deal with this modeling issue by extending the RUX-Method, a model-based method to build RIA UIs. The approach includes the validation process of the accessibility issues at two different levels: the UI structure and the interactions behavior.     

Two-Dimensional Compact Third-Order Polynomial Reconstructions. Solving Nonconservative Hyperbolic Systems Using GPUs

We present a new kind of high-order reconstruction operator of polynomial type, which is used in combination with the scheme presented in Castro et al. (J. Sci. Comput. 39:67?C114, 2009) for solving nonconservative hyperbolic systems. The implementation of the scheme is carried out on Graphics Processing Units (GPUs), thus achieving a substantial improvement of the speedup with respect to normal CPUs. As an application, the two-dimensional shallow water equations with geometrical source term due to the bottom slope is considered.     

End-user programming of a social robot by dialog

One of the main challenges faced by social robots is how to provide intuitive, natural and enjoyable usability for the end-user. In our ordinary environment, social robots could be important tools for education and entertainment (edutainment) in a variety of ways. This paper presents a Natural Programming System (NPS) that is geared to non-expert users. The main goal of such a system is to provide an enjoyable interactive platform for the users to build different programs within their social robot platform. The end-user can build a complex net of actions and conditions (a sequence) in a social robot via mixed-initiative dialogs and multimodal interaction. The system has been implemented and tested in Maggie, a real social robot with multiple skills, conceived as a general HRI researching platform. The robot’s internal features (skills) have been implemented to be verbally accessible to the end-user, who can combine them into others that are more complex following a bottom-up model. The built sequence is internally implemented as a Sequence Function Chart (SFC), which allows parallel execution, modularity and re-use. A multimodal Dialog Manager System (DMS) takes charge of keeping the coherence of the interaction. This work is thought for bringing social robots closer to non-expert users, who can play the game of “teaching how to do things” with the robot.     

Workload balancing in distributed crowd simulations: the partitioning method

The simulation of large crowds of autonomous agents with a realistic behavior is still a challenge for several computer research communities. Distributed architectures can provide scalability to crowd simulations, but they require the use of efficient partitioning methods. Although convex hulls have been shown as very efficient structures for crowd partitioning, providing efficient workload balancing to large scale simulations is still an open issue. In this paper, we propose the integration of a workload balancing technique for crowd simulations within a partitioning method based on convex hulls. The region-based balancing technique reassigns agents to servers using a criterion of distance. The performance evaluation results show that this technique ensures the saturation avoidance of the servers in an homogeneous distributed system. This feature can increase the scalability of crowd simulations.     

Artificial neural network onto eight bit microcontroller for Secchi depth calculation

In this paper we present a model to predict Secchi depth in water bodies by means of an artificial neural network application onto eight bit microcontroller. Water turbidity data were collected by both a Secchi disk and a new patented device (named LUZEX) that uses commercial photodiodes with not monochromatic sensitive band as a basis to perform “in situ” measurements for sunlight extinction coefficients. In order to have a wide range of turbidity data three different water bodies were selected to do the measurements. The developed neural network model is able to relate well the data obtained by these methods and the obtained value for regression coefficient (R) is 0.998.Secchi depth measure is a reference method to determine turbidity in continental and coastal water bodies, especially in the Mediterranean Sea region, but sometimes there are particular cases that makes difficult the use of the Secchi disk (e.g. shallow water bodies), the authors propose LUZEX as a substitute for Secchi disk when it is difficult or impossible to use.     

An ontological conceptualization approach for awareness in domain-independent collaborative modeling systems: Application to a model-driven development method

One of the most important aspects of collaborative systems is the concept of awareness, which refers to the perception and knowledge of the group and its activities. Support for the design and automatic development of awareness mechanisms within collaborative systems is hard to find. Furthermore, awareness conceptualizations are usually partial and differ greatly between the proposals of different authors. In response to these problems, we propose an awareness ontology that conceptualizes some of the most important aspects of awareness in a specific kind of system: collaborative systems for carrying out modeling activities. The awareness ontology brings together and extends a series of ontologies we have developed in the past. The ontology is prepared to better meet the specific implementation needs of a model-driven development approach. In order to validate the usefulness of this ontology, we relate its concepts to the awareness dimensions set out in Gutwin and Greenberg’s framework, and we apply the ontology to two systems presently in use.     

Network-based sparse Bayesian classification

In some classification problems there is prior information about the joint relevance of groups of features. This knowledge can be encoded in a network whose nodes correspond to features and whose edges connect features that should be either both excluded or both included in the predictive model. In this paper, we introduce a novel network-based sparse Bayesian classifier (NBSBC) that makes use of the information about feature dependencies encoded in such a network to improve its prediction accuracy, especially in problems with a high-dimensional feature space and a limited amount of available training data. Approximate Bayesian inference is efficiently implemented in this model using expectation propagation. The NBSBC method is validated on four real-world classification problems from different domains of application: phonemes, handwritten digits, precipitation records and gene expression measurements. A comparison with state-of-the-art methods (support vector machine, network-based support vector machine and graph lasso) show that NBSBC has excellent predictive performance. It has the best accuracy in three of the four problems analyzed and ranks second in the modeling of the precipitation data. NBSBC also yields accurate and robust rankings of the individual features according to their relevance to the solution of the classification problem considered. The accuracy and stability of these estimates is an important factor in the good overall performance of this method.     

Measuring effective leaf area index, foliage profile, and stand height in New England forest stands using a full-waveform ground-based lidar

Effective leaf area index (LAI) retrievals from a scanning, ground-based, near-infrared (1064 nm) lidar that digitizes the full return waveform, the Echidna Validation Instrument (EVI), are in good agreement with those obtained from both hemispherical photography and the Li-Cor LAI-2000 Plant Canopy Analyzer. We conducted trials at 28 plots within six stands of hardwoods and conifers of varying height and stocking densities at Harvard Forest, Massachusetts, Bartlett Experimental Forest, New Hampshire, and Howland Experimental Forest, Maine, in July 2007. Effective LAI values retrieved by four methods, which ranged from 3.42 to 5.25 depending on the site and method, were not significantly different (β < 0.1 among four methods). The LAI values also matched published values well. Foliage profiles (leaf area with height) retrieved from the lidar scans, although not independently validated, were consistent with stand structure as observed and as measured by conventional methods. Canopy mean top height, as determined from the foliage profiles, deviated from mean RH100 values obtained from the Lidar Vegetation Imaging Sensor (LVIS) airborne large-footprint lidar system at 27 plots by − 0.91 m with RMSE = 2.04 m, documenting the ability of the EVI to retrieve stand height. The Echidna Validation Instrument is the first realization of the Echidna® lidar concept, devised by Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO), for measuring forest structure using full-waveform, ground-based, scanning lidar.     

A Hierarchical Tracking Strategy for Vision-Based Applications On-Board UAVs

In this paper, we apply a hierarchical tracking strategy of planar objects (or that can be assumed to be planar) that is based on direct methods for vision-based applications on-board UAVs. The use of this tracking strategy allows to achieve the tasks at real-time frame rates and to overcome problems posed by the challenging conditions of the tasks: e.g. constant vibrations, fast 3D changes, or limited capacity on-board. The vast majority of approaches make use of feature-based methods to track objects. Nonetheless, in this paper we show that although some of these feature-based solutions are faster, direct methods can be more robust under fast 3D motions (fast changes in position), some changes in appearance, constant vibrations (without requiring any specific hardware or software for video stabilization), and situations in which part of the object to track is outside of the field of view of the camera. The performance of the proposed tracking strategy on-board UAVs is evaluated with images from real-flight tests using manually-generated ground truth information, accurate position estimation using a Vicon system, and also with simulated data from a simulation environment. Results show that the hierarchical tracking strategy performs better than well-known feature-based algorithms and well-known configurations of direct methods, and that its performance is robust enough for vision-in-the-loop tasks, e.g. for vision-based landing tasks.     

Time series forecasting by evolving artificial neural networks with genetic algorithms, differential evolution and estimation of distribution algorithm

Time series forecasting is an important tool to support both individual and organizational decisions (e.g. planning production resources). In recent years, a large literature has evolved on the use of evolutionary artificial neural networks (EANN) in many forecasting applications. Evolving neural networks are particularly appealing because of their ability to model an unspecified nonlinear relationship between time series variables. In this work, two new approaches of a previous system, automatic design of artificial neural networks (ADANN) applied to forecast time series, are tackled. In ADANN, the automatic process to design artificial neural networks was carried out by a genetic algorithm (GA). This paper evaluates three methods to evolve neural networks architectures, one carried out with genetic algorithm, a second one carried out with differential evolution algorithm (DE) and the last one using estimation of distribution algorithms (EDA). A comparative study among these three methods with a set of referenced time series will be shown. In this paper, we also compare ADANN forecasting ability against a forecasting tool called Forecast Pro^® (FP) software, using five benchmark time series. The object of this study is to try to improve the final forecasting getting an accurate system.