RESUMEN
Novel wearable tactile interfaces offer the possibility to simulate tactile interactions with virtual environments directly on our skin. But, unlike kinesthetic interfaces, for which haptic rendering is a well explored problem, they pose new questions about the formulation of the rendering problem. In this work, we propose a formulation of tactile rendering as an optimization problem, which is general for a large family of tactile interfaces. Based on an accurate simulation of contact between a finger model and the virtual environment, we pose tactile rendering as the optimization of the device configuration, such that the contact surface between the device and the actual finger matches as close as possible the contact surface in the virtual environment. We describe the optimization formulation in general terms, and we also demonstrate its implementation on a thimble-like wearable device. We validate the tactile rendering formulation by analyzing its force error, and we show that it outperforms other approaches.
Asunto(s)
Modelos Biológicos , Percepción del Tacto , Tacto , Interfaz Usuario-Computador , Realidad Virtual , Diseño de Equipo , Dedos , Humanos , Estimulación Física , Procesamiento de Señales Asistido por Computador , Dispositivos Electrónicos VestiblesRESUMEN
Dendritic spines are thin protrusions that cover the dendritic surface of numerous neurons in the brain and whose function seems to play a key role in neural circuits. The correct segmentation of those structures is difficult due to their small size and the resulting spines can appear incomplete. This paper presents a four-step procedure for the complete reconstruction of dendritic spines. The haptically driven procedure is intended to work as an image processing stage before the automatic segmentation step giving the final representation of the dendritic spines. The procedure is designed to allow both the navigation and the volume image editing to be carried out using a haptic device. A use case employing our procedure together with a commercial software package for the segmentation stage is illustrated. Finally, the haptic editing is evaluated in two experiments; the first experiment concerns the benefits of the force feedback and the second checks the suitability of the use of a haptic device as input. In both cases, the results shows that the procedure improves the editing accuracy.
Asunto(s)
Espinas Dendríticas , Procesamiento de Imagen Asistido por Computador/métodos , Tacto/fisiología , Interfaz Usuario-Computador , Adulto , Algoritmos , Retroalimentación Fisiológica , Femenino , Humanos , Imagenología Tridimensional , Masculino , Microscopía de Polarización , Programas Informáticos , Adulto JovenRESUMEN
"Bailahuén" is the common name of a medicinal shrub native to Chile where this resinous herb is widely used for its liver stimulating properties. Although the official species is Haplopappus baylahuen Remy (Asteraceae), other species of the same genus are also used in different regions as "bailahuén". A thin layer chromatography (TLC) method for rapid identification of different species and detection of adulterations is described for four of the species: Haplopappus baylahuen, Haplopappus taeda Reiche, Haplopappus multifolius Phil., and Haplopappus remyanus Wedd. To confirm efficiency in all species antioxidant properties were screened in resins, infusions, and methanolic extracts by tests of lipid peroxidation in erythrocytes and free radical scavenging activity by DPPH. In both studies Haplopappus baylahuen showed the lowest antioxidant capacity. In DPPH analyses, infusion and resins of Haplopappus baylahuen also showed the lowest and Haplopappus remyanus the major inhibiting activity of free radicals, while Haplopappus multifolius proved to have the highest result when the methanolic extracts were used. The chemical characterization of the studied species showed important levels of flavonoids and coumarins, with flavonoids predominating in Haplopappus taeda, coumarins in Haplopappus multifolius and both of them in Haplopappus baylahuen and Haplopappus remyanus.