Humanoid odometric localization integrating kinematic,inertial and visual information

We present a method for odometric localization of humanoid robots using standard sensing equipment, i.e., a monocular camera, an inertial measurement unit (IMU), joint encoders and foot pressure sensors. Data from all these sources are integrated using the prediction-correction paradigm of the Extended Kalman Filter. Position and orientation of the torso, defined as the representative body of the robot, are predicted through kinematic computations based on joint encoder readings; an asynchronous mechanism triggered by the pressure sensors is used to update the placement of the support foot. The correction step of the filter uses as measurements the torso orientation, provided by the IMU, and the head pose, reconstructed by a VSLAM algorithm. The proposed method is validated on the humanoid NAO through two sets of experiments: open-loop motions aimed at assessing the accuracy of localization with respect to a ground truth, and closed-loop motions where the humanoid pose estimates are used in real-time as feedback signals for trajectory control.     

Effects of discomfort glare on performance in attending peripheral visual information in displays

Large screens have become more popular in recent years. Because of the increasing size of displays, the amount of information presented in the peripheral visual field has gained importance in many tasks on visual display units. Users of displays are often exposed to some change or difference in luminance in or between different areas of a display, which in turn may produce a phenomenon known as discomfort glare. Discomfort glare is likely to affect cognitive performance. The performance in the visual periphery is more susceptible to disturbances as is the case for the performance in the central visual field.     

Free radical polymerization of unconjugated dienes: 18. Cyclopolymerization of o-divinylbenzene at 70°C

The free radical polymerization at 70°C of o-divinylbenzene in toluene solutions takes place according to a cyclopolymerization mechanism. By fitting the experimental data with two different relationships between the mole fraction of residual unsaturation in the polymers and the monomer concentration at which they were obtained, it has been possible to show that, in the chain propagation steps, intramolecular cyclization could occur involving the two monomeric units entered last in the polymer chain, with formation of seven-membered ring structures.     

Re-engineering legacy Web applications into RIAs by aligning modernization requirements,patterns and RIA features

Rich Internet Applications (RIAs) have become a common platform for Web developments. Its adoption has been accelerated thanks to different factors, among others, the appearance of patterns for typical RIA behaviors and the extension of different Model Driven Web Engineering methodologies to introduce RIA concepts. The real fact is that more and more developers are switching to RIA technologies and, thus, the modernization of legacy Web applications into RIAs has become a trend topic. However, this modernization process lacks of a systematic approach. Currently, it is done in an ad hoc manner, being expensive and error-prone. This work presents a systematic process to modernize legacy Web applications into RIAs. The process is based on the use of traceability matrices that relate modernization requirements, RIA features and patterns. Performing some operations on these matrices, they provide the analyst with the necessary information about the suitability of a pattern or set of patterns to address a given requirement. This work also introduces two measures, the degree of requirement realization and the degree of pattern realization, which are used to discuss the pattern selection. Finally, the applicability of the approach is evaluated by using it in several Web systems.     

Prostate Cancer Visualization from MR Imagery and MR Spectroscopy

Prostate cancer is one of the most prevalent cancers among males, and the use of magnetic resonance imaging (MRI) has been suggested for its detection. A framework is presented for scoring and visualizing various MR data in an efficient and intuitive manner. A classification method is introduced where a cumulative score volume is created which takes into account each of three acquisition types. This score volume is integrated into a volume rendering framework which allows the user to view the prostate gland, the multi‐modal score values, and the surrounding anatomy. A visibility persistence mode is introduced to automatically avoid full occlusion of a selected score and indicate overlaps. The use of GPU‐accelerated multi‐modal single‐pass ray casting provides an interactive experience. User driven importance rendering allows the user to gain insight into the data and can assist in localization of the disease and treatment planning. We evaluate our results against pathology and radiologists'determinations.     

Context preserving maps of tubular structures

When visualizing tubular 3D structures, external representations are often used for guidance and display, and such views in 2D can often contain occlusions. Virtual dissection methods have been proposed where the entire 3D structure can be mapped to the 2D plane, though these will lose context by straightening curved sections. We present a new method of creating maps of 3D tubular structures that yield a succinct view while preserving the overall geometric structure. Given a dominant view plane for the structure, its curve skeleton is first projected to a 2D skeleton. This 2D skeleton is adjusted to account for distortions in length, modified to remove intersections, and optimized to preserve the shape of the original 3D skeleton. Based on this shaped 2D skeleton, a boundary for the map of the object is obtained based on a slicing path through the structure and the radius around the skeleton. The sliced structure is conformally mapped to a rectangle and then deformed via harmonic mapping to match the boundary placement. This flattened map preserves the general geometric context of a 3D object in a 2D display, and rendering of this flattened map can be accomplished using volumetric ray casting. We have evaluated our method on real datasets of human colon models.     

A non-iterative and effective procedure for simultaneous odometry and camera calibration for a differential drive mobile robot based on the singular value decomposition

Differential-drive mobile robots are usually equipped with video cameras for navigation purposes. In order to ensure proper operational capabilities of such systems, several calibration steps are required to estimate the video-camera intrinsic and extrinsic parameters, the relative pose between the camera and the vehicle frame and the odometric parameters of the vehicle. In this paper, simultaneous estimation of the aforementioned quantities is achieved by a novel and effective calibration procedure. The proposed calibration procedure needs only a proper set of landmarks, on-board measurements given by the wheels encoders, and the camera (i.e., a number of properly taken camera snapshots of the set of landmarks). A major advantage of the proposed technique is that the robot is not required to follow a specific path: the vehicle is asked to roughly move around the landmarks and acquire at least three snapshots at some approximatively known configurations. Moreover, since the whole calibration procedure does not use external measurement devices, it can be used to calibrate, on-site, a team of mobile robots with respect to the same inertial frame, given by the position of the landmarks’ tool. Finally, the proposed algorithm is systematic and does not require any iterative step. Numerical simulations and experimental results, obtained by using a mobile robot Khepera III equipped with a low-cost camera, confirm the effectiveness of the proposed technique.     

Location of outliers in multiple regression using resampled values

Within the regression context, this method begins with the set of exactly fitted coefficients determined from each p-dimensional subset of the sample. Outlying points in this p-dimensional coefficient space correspond to outliers in the original n-dimensional data space. Resampled values are used to detect anomalous data points through a proposed detection rule that avoids masking and swamping and allows multiple outliers to be identified.     

A Conversational Approach to the Interaction With Web Services

The emerging standards for the specification of Web Services support the publication of the static interfaces of the operations they may execute. However, little attention is paid to the management of long-lasting interactions between the service providers and their consumers. Although this is not an issue in the case of "one-shot" services, it challenges the provision of services requiring the exchange of multiple messages between the business partners. In this article, we present a conversational model supporting the management of long-lasting interactions where several messages have to be exchanged before the service is completed. Our model aims at facilitating the consumers during the service invocation because in this way the establishment of short-term business relations can be simplified. To this extent, we provide a computational framework that can be exploited to manage a conversation between the consumer and the service provider. Our framework is inspired from the research developed in Computational Linguistics and in the area of Multi-Agent Systems to manage human-to-computer and agent-to-agent dialog. However, we employ techniques suitable to comply with the emerging Web Service standards and with the scalability requirements of the Internet.