Design recommendations for camera-based head-controlled interfaces that replace the mouse for motion-impaired users

This work focuses on camera-based systems that are designed for mouse replacement. Usually, these interfaces are based on computer vision techniques that capture the user’s face or head movements and are specifically designed for users with disabilities. The work identifies and reviews the key factors of these interfaces based on the lessons learnt by the authors’ experience and by a comprehensive analysis of the literature to describe the specific points to consider in their design. These factors are as follows: user features to track, initial user detection (calibration), position mapping, feedback, error recovery, event execution, profiles and ergonomics of the system. The work compiles the solutions offered by different systems to help new designers avoid problems already discussed by the others.     

Toward emotional interactive videogames for children with autism spectrum disorder

Universal Access in the Information Society - Technology and videogames have been proven as motivating tools for working attention and complex communication skills, especially in children with...     

Three-dimensional space-vector modulation algorithm for four-leg multilevel converters using abc coordinates

In this paper, a novel three-dimensional (3-D) space-vector algorithm for four-leg multilevel converters is presented. It can be applied to active power filters or neutral-current compensator applications for mitigating harmonics and zero-sequence components using abc coordinates (referred from now on this paper as natural coordinates). This technique greatly simplifies the selection of the 3-D region where a given voltage vector is supposed to be found. Compared to a three-level modulation algorithm for three-leg multilevel converters, this algorithm does not increase its complexity and the calculations of the active vectors with the corresponding switching time that generate the reference voltage vector. In addition, the low-computational cost of the proposed algorithm is always the same and it is independent of the number of levels of the converter.     

Comparison of color gamuts among several types of paper with the same printing technology

In this work, we have studied the relationship among the colorimetric properties of different types of paper, having different finishing and grammage. Their color reproduction capability has also been analyzed by using the same printing technology (inkjet printing). On the one hand, we have plotted CIELAB data under the illuminant D50 into constant lightness and hue‐angle planes to be compared with MacAdam limits and with Pointer's real‐world surface color. On the other hand, we have calculated the volume gamut of the color solid associated to each color paper gamut. Analyzing the results, we have checked that there is not any clear relationship among the colorimetric properties of paper (for instance, CIE whiteness index, etc.) and the color gamut volume associated. However, the colorimetric parameters associated to the printed sample showed a quite good linear correlation between the minimum lightness (or the maximum blackness value) of the printed color chart and the color gamut volume. In particular, the greatest color gamut volume corresponds to the glossy papers taking into account this correlation for inkjet printing. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 330–336, 2009     

Simulation of non-axisymmetric floating zone crystal growth under microgravity

The possibility of growing crystals of non-circular cross-section by using the floating zone technique is considered, basing the analysis on the isothermal liquid bridge model, and restricting the study to a linear asymptotic analysis. An almost square initial seed is considered in more detail, although the analysis is general and can be applied to other initial shapes, not only of the seed but also of the supply rod, that can be of any cross-section.     

Evaluation of on-line analytic and numeric inverse kinematics approaches driven by partial vision input

Despite its central role in the constitution of a truly enactive interface, 3D interaction through human full body movement has been hindered by a number of technological and algorithmic factors. Let us mention the cumbersome magnetic equipments, or the underdetermined data set provided by less invasive video-based approaches. In the present paper, we explore the recovery of the full body posture of a standing subject in front of a stereo camera system. The 3D position of the hands, the head and the center of the trunk segment are extracted in real-time and provided to the body posture recovery algorithmic layer. We focus on the comparison between numeric and analytic inverse kinematics approaches in terms of performances and overall quality of the reconstructed body posture. Algorithmic issues arise from the very partial and noisy input and the singularity of the human standing posture. Despite stability concerns, results confirm the pertinence of this approach in this demanding context.     

Multi-quantum-well lasers emitting at 1.55 mu m grown by GSMBE

GaInAs/GaInAsP multi-quantum-well structures emitting at 1.55 mu m have been realised by gas source molecular beam epitaxy (GSMBE) over a large range of growth temperature. Threshold current densities as low as 0.81 kA/cm/sup 2/ have been obtained. The first BH lasers fabricated by GSMBE from these heterostructures exhibit low threshold current (18 mA) and linear DC light-current characteristics up to 20 mW.<>     

Cold metastases detected by bone scintigraphy in aggressive lung cancer

A case of a 55-year-old man was remitted to Traumatology Department to present back pain of two weeks of evolution. The results of bone scintigraphy and the patient's evolution allowed the diagnosis. This case report and a literature review showed the importance of using a routine bone scan in diagnosis of bone metastases.     

Laparoscopic splenectomy as an alternative to open surgery in the treatment of autoimmune thrombocytopenia

BACKGROUND: Several studies have shown the potential advantages laparoscopic splenectomy (LS) over open surgery. The aim of this study has been to evaluate the advantages of LS over open surgery in the treatment of autoimmune thrombocytopenia. PATIENTS AND METHODS: 54 consecutive patients splenectomized for the treatment of idiopathic thrombocytopenic purpura (ITP) or HIV-related thrombocytopenia were analyzed. Operative features (operative time, conversion to open surgery, accessory spleens), immediate (stay, analgesia and blood transfusion requirements) and late postoperative features (platelet count), as well as splenectomy-related complications in both surgical procedures were compared. RESULTS: Between February 1990 and February 1997, 54 splenctomies were performed for the treatment of autoimmune thrombocytopenia (ITP, n = 47, and HIV-related thrombocytopenia, n = 7). Eighteen were performed through an open approach, and 36 by laparoscopy. Both groups were comparable with regard to age, sex, platelet count, disease duration and body mass index. LS was completed in 34 cases (conversion to open surgery: 5.5%). The incidence of accessory spleens was 11% in the LS group and 5.5% in the open surgery group. Postoperative morbidity (16% vs 28%) and blood requirements (25% vs 33%) were lower after LS, but the differences did not reach statistical significance. Analgesia requirements (7 [SD 3] vs 11 [6]; p < 0.01) and postoperative stay (3.8 [2.6] vs 7.4 [3] days; p < 0.01) were significantly shorter after LS. Following splenectomy, the platelet counts became normal in 72% of patients submitted to LS and 78% of patients in the open surgery group. After 20 and 63 months mean follow-up, one patient in each group developed late complications. CONCLUSION: As compared to open surgery, LS offers a better immediate clinical outcome, with similar long-term results.