Vibrotactile and friction texture displays are good options for artificially presenting the roughness and frictional properties of textures, respectively. These two types of displays are compatible with touch panels and exhibit complementary characteristics. We combine vibrotactile and electrostatic friction texture displays to improve the quality of virtual textures, considering that actual textured surfaces are composed of both properties. We investigate their composition ratios when displaying roughness textures. Grating roughness scales with one of the six surface wavelengths are generated under 11 display conditions, and in 9 of which, vibrotactile and friction stimuli are combined with different composition ratios. A forced-choice experiment regarding subjective realism indicates that a vibrotactile stimulus with a slight variable-friction stimulus is effective for presenting quality textures for surface wavelengths greater than or equal to 1.0mm.

This study demonstrates that the simultaneous use of two types of representative principles for tactile texture displays, vibrotactile and electrostatic friction stimulation surpasses either type of stimulation. We used a set of sinusoidal grating scales with different surface spatial periods as simulated textured surfaces for testing the quality of texture displays. Experimental participants judged the best stimulus condition among the vibrotactile, electrostatic friction, and the conjunctive stimuli in terms of the reality perceived from the simulated texture stimuli. The use of vibrotactile and electrostatic stimuli in conjunction was judged to be the most realistic for the spatial periods of 1 and 2 mm, whereas noticeable differences among the three stimuli conditions were not reported for small spatial periods of 0.2 and 0.5 mm. The simultaneous use is effective for simulating the surfaces with middle-level asperity.

The present study investigates the augmentation effect of airflow on the sensation of a virtual reality walk. The intensity of cutaneous sensation evoked by airflow during the real and virtual walk was measured. The airflow stimulus was added to the participant with passive vestibular motion and visual presentation. The result suggests that the sensation of walking was strongly increased by adding the airflow stimulus to the vestibular and optic presentations. The cutaneous sensation of airflow was perceived higher for the sitting participant than during a real walk in both a single and the combined stimuli. The equivalent speed of airflow for the sitting participant was lowered from the airflow speed in the real walk.

Non-Hodgkin's lymphoma is a disseminated, highly malignant cancer, with resistance to drug treatment based on molecular- and tissue-scale characteristics that are intricately linked. A critical element of molecular resistance has been traced to the loss of functionality in proteins such as the tumor suppressor p53. We investigate the tissue-scale physiologic effects of this loss by integrating in vivo and immunohistological data with computational modeling to study the spatiotemporal physical dynamics of lymphoma growth. We compare between drug-sensitive Eμ-myc Arf-/- and drug-resistant Eμ-myc p53-/- lymphoma cell tumors grown in live mice. Initial values for the model parameters are obtained in part by extracting values from the cellular-scale from whole-tumor histological staining of the tumor-infiltrated inguinal lymph node in vivo. We compare model-predicted tumor growth with that observed from intravital microscopy and macroscopic imaging in vivo, finding that the model is able to accurately predict lymphoma growth. A critical physical mechanism underlying drug-resistant phenotypes may be that the Eμ-myc p53-/- cells seem to pack more closely within the tumor than the Eμ-myc Arf-/- cells, thus possibly exacerbating diffusion gradients of oxygen, leading to cell quiescence and hence resistance to cell-cycle specific drugs. Tighter cell packing could also maintain steeper gradients of drug and lead to insufficient toxicity. The transport phenomena within the lymphoma may thus contribute in nontrivial, complex ways to the difference in drug sensitivity between Eμ-myc Arf-/- and Eμ-myc p53-/- tumors, beyond what might be solely expected from loss of functionality at the molecular scale. We conclude that computational modeling tightly integrated with experimental data gives insight into the dynamics of Non-Hodgkin's lymphoma and provides a platform to generate confirmable predictions of tumor growth.

Visual tracking plays an important role in various robotic tasks. We have developed a view-based visual tracking system to cope with change of the appearance of the template in a 3D environment using affine transformed templates. In view-based visual tracking, however, there are still critical situations in which the tracking fails because of occlusion by general objects and/or human hand in the environment, particularly in cases where humans and robots perform cooperative handling of objects. The paper presents two methods to cope with such occlusion problems. The first method detects the occlusion based on an evaluation of correlation errors in a tessellated template. The second method uses infrared images to detect the region occluded by human hand in the target template. The system then creates a mask of the occluded region and eliminates pixels in the mask from the calculation of correlation with the template image. In the prototype system, the generation of the mask and the correlation can be performed, typically, in one TV frame. We have integrated the proposed methods into the view-based visual tracking system which we have already developed. Experimental results demonstrate the usefulness of the proposed methods.

This paper presents a view-based visual tracking system. View-based systems are more general than the other approaches which require analysis of 2D image features and matching with 3D models. For the image correlation, we use a visual tracking hardware based on a block matching algorithm. One problem of the block matching is how to cope with changes of the template's appearance in the 3D environment. Consequently, the system generates affine transformed templates corresponding to various orientations of the target image plane. We use geodesic domes not only for uniform distribution of the 3D orientations of the template image plane, but also for dynamic transition in groups of the candidate templates for the next search step. Experimental results demonstrate the usefulness of the proposed system.

A new type of master robot for teleoperation is proposed. In the proposed master robot, several wires are stretched from a handle which is moved by a human operator. In this paper, the authors explain how many wires are necessary to control a handle with six degrees of freedom in a three dimensional space. Moreover, to feed forces from a slave robot to the handle, an algorithm to determine each wire tension is proposed. Finally, they show experimental results in which a handle is moved by seven wires in a three dimensional space.