Challenges in Development of Sub-Millimeter Resolution Thermo-Fluidic Actuator Based Wearable Tactile Display System for Blind Individuals

2011 ◽  
Author(s):  
Prakash C. R. J. Naidu ◽  
Ramesh Yechangunja ◽  
Andrea Prosperetti ◽  
Mandayam A. Srinivasan
Keyword(s):  
Spatial Resolution ◽  
Bubble Formation ◽  
Tactile Display ◽  
Switching Frequency ◽  
Display System ◽  
Prototype Development ◽  
Fluidic Actuators ◽  
Spatio Temporal ◽  
Human Finger ◽  
Blind Individuals

This paper presents the work conducted towards the realization of a novel tactile display system composed of miniature thermo-fluidic actuators. An application of the system particularly relevant to blind individuals is communication with computers through touch. The development of programmable spatio-temporal pattern of touch actuation based on bubble formation and vapor pressure has remarkable scope, not only because of the flexibility and wearability but also the high levels of motion amplitude and force of actuation not achieved so far by other means. The design specifications of the tactile display involved packaging of the miniature actuators in such a manner that the display can be conveniently attached at the tip of the human finger with desirable spatial resolution, and achieving the optimum force that can be felt through the human finger. However, there were challenges that were faced by the authors while miniaturizing the actuators for suitability in sub-millimeter spatial resolution desirable for the tactile display. The paper reports on the design, prototype development and experimental results and brings out the limitations along with possible solutions being pursued by the authors. The progressive efforts through fabrication and testing of different prototype thermo-fluidic actuators ranging from 3mm diameter bore to sub-millimeter sizes and the corresponding difficulties faced in the form of cooling requirements, hysteresis effects, and fabrication challenges are elucidated. The paper reports on packaging of actuators as an array of tiny tubes spaced as close as possible, and establishment of parameters, namely, amplitude of actuation and switching frequency, along with force generation adequate for tactile perception.

Configuration of a Novel Sub-Millimeter Resolution Piezoelectric Actuator Based Wearable Tactile Display System for Blind Individuals

2011 ◽  
Author(s):  
Prakash C. R. J. Naidu ◽  
Ramesh Yechangunja ◽  
Mandayam A. Srinivasan
Keyword(s):  
Piezoelectric Actuators ◽  
Body Part ◽  
Tactile Display ◽  
Significant Feature ◽  
Block Type ◽  
Display Device ◽  
Display System ◽  
Potential Applications ◽  
Blind Individuals ◽  
General Communication

This paper presents the work conducted towards the realization of a novel tactile display system, first using block type piezoelectric actuators and later using cantilever type piezoelectric actuators. The system is particularly useful for blind users to communicate with computers through touch, but also has many potential applications in several other fields such as virtual reality, gaming, and other general communication interfaces for sighted users. Although piezoelectric actuators have been used in the past in electronic Braille and other systems, there is no reported configuration that can achieve sub-millimeter center-to-center resolution in an array of programmable actuation pins that act as interfaces in contact with a human body part such as a finger. This paper reports development of a wearable tactile display device: (a) built of block type actuators and its characterization showing that the perception was not adequate for certain purposes; (b) further, a novel arrangement with considerable improvement in perception wherein- (i) two or more vibrating stimulation pins can be located close to each other at the plane of contact with a finger, and (ii) actuated by means of piezoelectric bending elements arranged in a cantilever configuration partially overlapping each other in multiple planes. A significant feature of the unique configuration reported in this paper is that vibratory stimulation can be achieved at finer spatial resolutions than hitherto achieved.

Investigation of Local Dynamics on the Sub-micron Scale in Organic Blends Using an Ultrafast Confocal Microscope

2010 ◽  
Vol 1270 ◽  
Author(s):  
Giulia Grancini ◽  
Dario Polli ◽  
Jenny Clark ◽  
Tersilla Virgili ◽  
Giulio Cerullo ◽  
...  
Keyword(s):  
Excited State ◽  
Confocal Microscopy ◽  
Polymer Blends ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
Electronic States ◽  
Pump Probe ◽  
Peculiar Behaviour ◽  
Spatio Temporal ◽  
Probe Spectroscopy

AbstractWe introduce a novel instrument combining femtosecond pump-probe spectroscopy and confocal microscopy for spatio-temporal imaging of excited-state dynamics of phase-separated polymer blends. Phenomena occurring at interfaces between different materials are crucial for optimizing the device performances, but are poorly understood due to the variety of possible electronic states and processes involved and to their complicated dynamics. Our instrument (with 200-fs temporal resolution and 300-nm spatial resolution) provides new insights into the properties of polymer blends, revealing spatially variable photo-relaxation paths and dynamics and highlighting a peculiar behaviour at the interface between the phase-separated domains.

Kurzweil Reading Machine: Evaluation of Model One

1978 ◽  
Vol 72 (10) ◽  
pp. 415-418
Author(s):  
Lawrence A. Scadden
Keyword(s):  
Comprehensive Evaluation ◽  
Evaluation Process ◽  
Tactile Display ◽  
Final Report ◽  
Work Related ◽  
Reading Material ◽  
Stage Of Development ◽  
Early Fall ◽  
Blind Individuals ◽  
Evaluation Project

In summary, the evaluation of the KRM has demonstrated that this approach and this specific machine can permit immediate access to printed material by most blind individuals. The greatest limitation at this stage of development is related to the confidence level that many users have placed in the ability of the machine to read various kinds of reading material. This factor has limited the use of the machine as an aid to employment of blind people. It is believed that many of the problems identified in the evaluation process can be overcome with further research and development of the KRM. The evaluation of the KRM by blind and sighted individuals throughout the country has led to the unanimous conclusion that further investigations with improved models of the KRM are warranted. The software in the existing models should be improved to eliminate some of the problems identified above. Hardware changes should be made to eliminate other identified problems. The concern regarding the lack of use of the KRM by employed blind individuals residing close to existing machines probably cannot be alleviated until reading machines of this kind can be located within the actual employment situation. Blind individuals are not willing, nor should they be, to travel to where machines are located in order to read work related materials. Other alternatives, including sighted readers, can be utilized within a work setting. This conclusion suggests the necessity of reaching the point at which speech-output reading machines can be affordable by individuals. Postscript: Since the completion of this evaluation project and the submission of the final report to the supporting governmental agency and to the manufacturer, KCP announced plans for Model Three of the KRM, a desk-top unit. The design includes most of the recommendations suggested in this report such as a hand-scanning option, a small tactile display to assist in format recognition, automatic contrast control with manual override capability, and a spell-next-letter feature. In addition, KCP announced several innovative features. The new model will permit the improved speech synthesizer to speak at rates up to 250 words per minute. Model Three will also have the capability of attaching to a braille embosser to provide direct print to braille conversion. The unit can also be attached to a computer to provide immediate full vocabulary output for computers. A new program is being developed to be used with all KRM's to permit the reading machines to be used as high-powered, programmable, scientific calculators. The new models and programs are scheduled for distribution in early fall 1978. Comprehensive evaluation of these advances is planned.

scholarly journals Spatio-Temporal Super-Resolution Land Cover Mapping Based on Fuzzy C-Means Clustering

2018 ◽  
Vol 10 (8) ◽  
pp. 1212 ◽  
Author(s):  
Xiaohong Yang ◽  
Zhong Xie ◽  
Feng Ling ◽  
Xiaodong Li ◽  
Yihang Zhang ◽  
...  
Keyword(s):  
Land Cover ◽  
Spatial Pattern ◽  
Spatial Resolution ◽  
Super Resolution ◽  
Land Cover Mapping ◽  
Fuzzy C Means Clustering ◽  
Land Cover Map ◽  
Spatio Temporal ◽  
Fine Resolution ◽  
Land Cover Maps

Super-resolution land cover mapping (SRM) is a method that aims to generate land cover maps with fine spatial resolutions from the original coarse spatial resolution remotely sensed image. The accuracy of the resultant land cover map produced by existing SRM methods is often limited by the errors of fraction images and the uncertainty of spatial pattern models. To address these limitations in this study, we proposed a fuzzy c-means clustering (FCM)-based spatio-temporal SRM (FCM_STSRM) model that combines the spectral, spatial, and temporal information into a single objective function. The spectral term is constructed with the FCM criterion, the spatial term is constructed with the maximal spatial dependence principle, and the temporal term is characterized by the land cover transition probabilities in the bitemporal land cover maps. The performance of the proposed FCM_STSRM method is assessed using data simulated from the National Land Cover Database dataset and real Landsat images. Results of the two experiments show that the proposed FCM_STSRM method can decrease the influence of fraction errors by directly using the original images as the input and the spatial pattern uncertainty by inheriting land cover information from the existing fine resolution land cover map. Compared with the hard classification and FCM_SRM method applied to mono-temporal images, the proposed FCM_STSRM method produced fine resolution land cover maps with high accuracy, thus showing the efficiency and potential of the novel approach for producing fine spatial resolution maps from coarse resolution remotely sensed images.

Valveless microliter combustion for densely packed arrays of powerful soft actuators

2021 ◽  
Vol 118 (39) ◽  
pp. e2106553118
Author(s):  
Ronald H. Heisser ◽  
Cameron A. Aubin ◽  
Ofek Peretz ◽  
Nicholas Kincaid ◽  
Hyeon Seok An ◽  
...  
Keyword(s):  
Tactile Stimulation ◽  
Exothermic Reaction ◽  
Tactile Display ◽  
Metal Electrodes ◽  
Pneumatic Actuators ◽  
Display Technology ◽  
Fluidic Actuators ◽  
Operational Frequency ◽  
Soft Actuators ◽  
Flame Behavior

Existing tactile stimulation technologies powered by small actuators offer low-resolution stimuli compared to the enormous mechanoreceptor density of human skin. Arrays of soft pneumatic actuators initially show promise as small-resolution (1- to 3-mm diameter), highly conformable tactile display strategies yet ultimately fail because of their need for valves bulkier than the actuators themselves. In this paper, we demonstrate an array of individually addressable, soft fluidic actuators that operate without electromechanical valves. We achieve this by using microscale combustion and localized thermal flame quenching. Precisely, liquid metal electrodes produce sparks to ignite fuel lean methane–oxygen mixtures in a 5-mm diameter, 2-mm tall silicone cylinder. The exothermic reaction quickly pressurizes the cylinder, displacing a silicone membrane up to 6 mm in under 1 ms. This device has an estimated free-inflation instantaneous stroke power of 3 W. The maximum reported operational frequency of these cylinders is 1.2 kHz with average displacements of ∼100 µm. We demonstrate that, at these small scales, the wall-quenching flame behavior also allows operation of a 3 × 3 array of 3-mm diameter cylinders with 4-mm pitch. Though we primarily present our device as a tactile display technology, it is a platform microactuator technology with application beyond this one.

scholarly journals A Simple Spatio–Temporal Data Fusion Method Based on Linear Regression Coefficient Compensation

2020 ◽  
Vol 12 (23) ◽  
pp. 3900
Author(s):  
Bingxin Bai ◽  
Yumin Tan ◽  
Gennadii Donchyts ◽  
Arjen Haag ◽  
Albrecht Weerts
Keyword(s):  
Linear Regression ◽  
Data Fusion ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
Fusion Method ◽  
Temporal Data ◽  
Resolution Image ◽  
Coarse Resolution ◽  
Fine Spatial Resolution ◽  
Spatio Temporal

High spatio–temporal resolution remote sensing images are of great significance in the dynamic monitoring of the Earth’s surface. However, due to cloud contamination and the hardware limitations of sensors, it is difficult to obtain image sequences with both high spatial and temporal resolution. Combining coarse resolution images, such as the moderate resolution imaging spectroradiometer (MODIS), with fine spatial resolution images, such as Landsat or Sentinel-2, has become a popular means to solve this problem. In this paper, we propose a simple and efficient enhanced linear regression spatio–temporal fusion method (ELRFM), which uses fine spatial resolution images acquired at two reference dates to establish a linear regression model for each pixel and each band between the image reflectance and the acquisition date. The obtained regression coefficients are used to help allocate the residual error between the real coarse resolution image and the simulated coarse resolution image upscaled by the high spatial resolution result of the linear prediction. The developed method consists of four steps: (1) linear regression (LR), (2) residual calculation, (3) distribution of the residual and (4) singular value correction. The proposed method was tested in different areas and using different sensors. The results show that, compared to the spatial and temporal adaptive reflectance fusion model (STARFM) and the flexible spatio–temporal data fusion (FSDAF) method, the ELRFM performs better in capturing small feature changes at the fine image scale and has high prediction accuracy. For example, in the red band, the proposed method has the lowest root mean square error (RMSE) (ELRFM: 0.0123 vs. STARFM: 0.0217 vs. FSDAF: 0.0224 vs. LR: 0.0221). Furthermore, the lightweight algorithm design and calculations based on the Google Earth Engine make the proposed method computationally less expensive than the STARFM and FSDAF.

scholarly journals Defining a Trade-off Between Spatial and Temporal Resolution of a Geosynchronous SAR Mission for Soil Moisture Monitoring

2018 ◽  
Vol 10 (12) ◽  
pp. 1950 ◽  
Author(s):  
Luca Cenci ◽  
Luca Pulvirenti ◽  
Giorgio Boni ◽  
Nazzareno Pierdicca
Keyword(s):  
Soil Moisture ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
Added Value ◽  
Sar Images ◽  
Radar Images ◽  
Spatio Temporal ◽  
Set Up ◽  
The Impact ◽  
Hydrological Applications

The next generation of synthetic aperture radar (SAR) systems could foresee satellite missions based on a geosynchronous orbit (GEO SAR). These systems are able to provide radar images with an unprecedented combination of spatial (≤1 km) and temporal (≤12 h) resolutions. This paper investigates the GEO SAR potentialities for soil moisture (SM) mapping finalized to hydrological applications, and defines the best compromise, in terms of image spatio-temporal resolution, for SM monitoring. A synthetic soil moisture–data assimilation (SM-DA) experiment was thus set up to evaluate the impact of the hydrological assimilation of different GEO SAR-like SM products, characterized by diverse spatio-temporal resolutions. The experiment was also designed to understand if GEO SAR-like SM maps could provide an added value with respect to SM products retrieved from SAR images acquired from satellites flying on a quasi-polar orbit, like Sentinel-1 (POLAR SAR). Findings showed that GEO SAR systems provide a valuable contribution for hydrological applications, especially if the possibility to generate many sub-daily observations is sacrificed in favor of higher spatial resolution. In the experiment, it was found that the assimilation of two GEO SAR-like observations a day, with a spatial resolution of 100 m, maximized the performances of the hydrological predictions, for both streamflow and SM state forecasts. Such improvements of the model performances were found to be 45% higher than the ones obtained by assimilating POLAR SAR-like SM maps.

scholarly journals Advances in mapping malaria for elimination: fine resolution modelling of Plasmodium falciparum incidence

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Victor A. Alegana ◽  
Peter M. Atkinson ◽  
Christopher Lourenço ◽  
Nick W. Ruktanonchai ◽  
Claudio Bosco ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Population Distribution ◽  
Malaria Incidence ◽  
World Health Organisation ◽  
World Health ◽  
Fine Spatial Resolution ◽  
Multi Temporal ◽  
Spatio Temporal ◽  
Fine Resolution ◽  
And Control

Abstract The long-term goal of the global effort to tackle malaria is national and regional elimination and eventually eradication. Fine scale multi-temporal mapping in low malaria transmission settings remains a challenge and the World Health Organisation propose use of surveillance in elimination settings. Here, we show how malaria incidence can be modelled at a fine spatial and temporal resolution from health facility data to help focus surveillance and control to population not attending health facilities. Using Namibia as a case study, we predicted the incidence of malaria, via a Bayesian spatio-temporal model, at a fine spatial resolution from parasitologically confirmed malaria cases and incorporated metrics on healthcare use as well as measures of uncertainty associated with incidence predictions. We then combined the incidence estimates with population maps to estimate clinical burdens and show the benefits of such mapping to identifying areas and seasons that can be targeted for improved surveillance and interventions. Fine spatial resolution maps produced using this approach were then used to target resources to specific local populations, and to specific months of the season. This remote targeting can be especially effective where the population distribution is sparse and further surveillance can be limited to specific local areas.

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