Anupam Pathak - Academia.edu (original) (raw)

Papers by Anupam Pathak

This publication describes systems and techniques for a computing device that includes multiple t... more This publication describes systems and techniques for a computing device that includes multiple touch screens that enables a user to cause the computing device to update the graphical user interface (GUI) being outputted by a first touch screen of the computing device by providing gesture input at a second touch screen of the computing device. For example, a mobile computing device, such as a foldable smartphone, may include two touch screens that can be folded up to 360 degrees so that the two touch screens face away from each other in a back-toback position. When such a mobile computing device is being used by a user, a first touch screen may face towards the user while a second touch screen may face away from the user. As the first touch screen of the mobile computing device outputs content that is viewable by the user, the user may interact with the second touch screen of the mobile computing device, such as by providing or performing touch input (e.g., gesture input) at the second touch screen to cause the mobile computing device to change, modify, or update the content outputted by the first touch screen. For example, the user may perform a gesture input at the second touch screen that causes the mobile computing device to zoom in and/or out of content displayed at the first touch screen. By enabling the user to interact with the second touch screen of the mobile computing device to change, modify, or update the content outputted by the first touch screen of the mobile computing device, the mobile computing device allows the user to interact with the computing device via touch-based input without the user's finger occluding the user's view of content being outputted by the first touch screen of the computing device.

Heart rate (HR) is a crucial physiological signal that can be used to monitor health and fitness.... more Heart rate (HR) is a crucial physiological signal that can be used to monitor health and fitness. Traditional methods for measuring HR require wearable devices, which can be inconvenient or uncomfortable, especially during sleep and meditation. Noncontact HR detection methods employing microwave radar can be a promising alternative. However, the existing approaches in the literature usually use high-gain antennas and require the sensor to face the user’s chest or back, making them difficult to integrate into a portable device and unsuitable for sleep and meditation tracking applications. This study presents a novel approach for noncontact HR detection using a miniaturized Soli radar chip embedded in a portable device (Google Nest Hub). The chip has a 6.5 mm × 5 mm × 0.9 mm dimension and can be easily integrated into various devices. The proposed approach utilizes advanced signal processing and machine learning techniques to extract HRs from radar signals. The approach is validated o...

Braille is a set of 3-by-2 tactile patterns that have a one-to-one mapping with the English alpha... more Braille is a set of 3-by-2 tactile patterns that have a one-to-one mapping with the English alphabet utilized by the visually impaired to read and write. Techniques of this disclosure enable a computing device, such as a smartphone, tablet, wearable device (e.g., smart watch), laptop, etc., to activate particular patterns of haptic motors of the computing device that correspond to each character. The computing device may digitally encode the text shown on the display into braille dots using an on-device character recognition system. When the user raster-scans their finger over different pixels of the screen, the computing device determines the particular braille dots at the location of the user's finger and activates a pattern of haptic motors corresponding to the particular pattern of braille dots at the location of the user's finger. In this way, the user may perceive a haptic pattern that corresponds to the pattern of the braille dots that the user is "touching" on a computing device without requiring physical morphing the display and without requiring physical modification of the computing device. DESCRIPTION Braille is a set of 3-by-2 tactile patterns that have a one-to-one mapping with the English alphabet utilized by the visually impaired to read and write. However, modern smartphones do not support conventional Braille as there is no straightforward way to mechanically morph smartphone displays. While visually impaired users may utilize a screen reader or other software to read aloud information shown on the display, other people in proximity to the visually impaired user may also be able to hear the contents of the display being read aloud, which may have privacy implications.

npj Digital Medicine, 2019

Technological advances in passive digital phenotyping present the opportunity to quantify neurolo... more Technological advances in passive digital phenotyping present the opportunity to quantify neurological diseases using new approaches that may complement clinical assessments. Here, we studied multiple sclerosis (MS) as a model neurological disease for investigating physiometric and environmental signals. The objective of this study was to assess the feasibility and correlation of wearable biosensors with traditional clinical measures of disability both in clinic and in free-living in MS patients. This is a single site observational cohort study conducted at an academic neurological center specializing in MS. A cohort of 25 MS patients with varying disability scores were recruited. Patients were monitored in clinic while wearing biosensors at nine body locations at three separate visits. Biosensor-derived features including aspects of gait (stance time, turn angle, mean turn velocity) and balance were collected, along with standardized disability scores assessed by a neurologist. Par...

2022 IEEE International Conference on Pervasive Computing and Communications (PerCom)

We present LuckyChirp, a contactless, passive, opportunistic respiratory tracking solution for co... more We present LuckyChirp, a contactless, passive, opportunistic respiratory tracking solution for commodity device using cascaded sonar modeling. Compared to conventional sonar methods that only solve the respiratory estimation problem (“what is the respiratory rate”), LuckyChirp also solves the additional respiratory detection problem (“is the human present and static enough for respiration sensing”). LuckyChirp uses a custom neural network on pulsed sonar’s wavelet transformed features to detect respiration. The classifier is then cascaded with a respiratory rate estimator. Such holistic design eliminates user friction of manually activating the system and enables passive respiration monitoring for all-day natural use. With Google Nest Hub and Pixel 4 as experimental devices, LuckyChirp achieves a mean absolute error of 0.48±0.98 and 1.07±1.67 breaths/min, respectively, for 20 users participating in a whole-night study. Compared to direct respiratory estimation without respiration classification, this is a ×6 (Nest Hub) and ×4 (Pixel) reduction in error.

Neurology, 2016

Objective: Demonstrate the feasibility of accurately estimating clinical tremor severity using an... more Objective: Demonstrate the feasibility of accurately estimating clinical tremor severity using an eating utensil (Liftware, Google Life Sciences) capable of measuring and compensating hand tremor. Background: Essential tremor (ET) and Parkinsons disease (PD) cause postural and action tremor that can severely limit person9s ability to eat and thus significantly decrease quality of life. In current clinical practice, tremor is assessed in the clinic commonly by tremor rating scales and less often with tremor analysis. Tools for assessing symptoms outside the clinic are virtually non-existent. An eating utensil capable of estimating tremor severity would allow for daily, longitudinal tremor assessment. Methods: Thirteen subjects (9M/4F, 8PD/5ET, ages 69+/-6.5) performed two tasks (5 trials moving food from plate to mouth, and 5 trials transferring food from plate to plate) using a spoon (Liftware) with tremor-cancellation technology and motion sensing (triaxial accelerometer and gyrosc...

Neurology, 2013

OBJECTIVE: To demonstrate the effectiveness of a handheld device on reducing tremor, using Active... more OBJECTIVE: To demonstrate the effectiveness of a handheld device on reducing tremor, using Active Cancellation of Tremor (ACT) technology. BACKGROUND: Essential Tremor (ET) causes action tremors that can severely limit a person9s ability to eat, resulting in decreased quality of life. A compact, handheld, battery-powered device is presented that stabilizes a spoon when shaken by an unsteady hand. The device employs ACT technology to sense motion, detect whether the motion is tremor, and move the spoon to cancel tremor. DESIGN/METHODS: Eleven subjects (9M/2F) with ET performed three tasks (holding, eating, and transferring objects) using a spoon device with ACT turned on and off. Tremor amplitude during these tasks was measured using accelerometers embedded in the device. Tremor was rated clinically by a neurologist using the Fahn-Tolosa-Marin Tremor Rating Scale, and overall improvement was rated by the subject using the Clinical Global Impression Scale (CGI-S). Both subject and neu...

Journal of Parkinson's Disease, 2017

We demonstrate the feasibility of estimating clinical tremor scores using an eating utensil with ... more We demonstrate the feasibility of estimating clinical tremor scores using an eating utensil with motion-sensing and tremor-cancellation technology in thirteen patients with tremor. Three experts scored hand tremor using the modified Fahn-Tolosa-Marin (FTM) scale. A linear model was trained to estimate tremor severity using the recorded motion signals. The average neurologist FTM score was 1.6 ± 0.7 for PD and 2.6 ± 0.7 for ET patients. The average model score was 1.6 ± 0.7 for PD and 2.6 ± 0.6 for ET. Correlation coefficient between the clinical and model tremor scores was 0.91 (p < 0.001). Motion data from an instrumented eating utensil accurately derived tremor ratings enabling practical, objective daily monitoring.

Active and Passive Smart Structures and Integrated Systems 2009, 2009

ABSTRACT

Modeling, Signal Processing, and Control for Smart Structures 2007, 2007

Due to physiologically induced body tremors, there is a need for active stabilization in many han... more Due to physiologically induced body tremors, there is a need for active stabilization in many hand-held devices such as surgical tools, optical equipment (cameras), manufacturing tools, and small arms weapons. While active stabilization has been achieved with electromagnetic and piezoceramics actuators for cameras and surgical equipment, the hostile environment along with larger loads introduced by manufacturing and battlefield environments make

SPIE Proceedings, 2008

In urban combat environments where it is common to have unsupported firing positions, wobble sign... more In urban combat environments where it is common to have unsupported firing positions, wobble significantly decreases shooting accuracy reducing mission effectiveness and soldier survivability. The SMASH (SMA Stabilizing Handgrip) has been developed to ...

Industrial and Commercial Applications of Smart Structures Technologies 2008, 2008

Shape memory alloy (SMA) wires are used increasingly in place of traditional actuators because of... more Shape memory alloy (SMA) wires are used increasingly in place of traditional actuators because of their compactness, high work density, low cost, ruggedness, high force generation, and relatively large strains. One well known issue with SMA wires is degradation in performance as ...

Smart Materials, Adaptive Structures and Intelligent Systems, Volume 1, 2008

Modern developments in Shape Memory Alloys (SMA) has positioned the material as an attractive alt... more Modern developments in Shape Memory Alloys (SMA) has positioned the material as an attractive alternative actuation for high yield, low cost industries which stand to benefit from the materials simple form, light weight, and high energy densities. However, the speed and predictability still remain as a barrier to its acceptance and usage. The robotics community has shown promising results with antagonistic actuation architectures to increase the cyclic speed and produce controlled motions; however, such control-based approaches generally require sensing and feedback implementations and tuning that are undesirable for high production products. This paper presents a simple but effective physically-based thermodynamic model for generic antagonistic actuation architecture. The model is derived from three sets of equations: differential equations describing the thermomechanical phase transformation behavior of the material, compatibility equations specific to the antagonistic configurati...

Smart Structures and Materials 2006: Modeling, Signal Processing, and Control, 2006

Due to stresses encountered in combat, it is known that soldier marksmanship noticeably decreases... more Due to stresses encountered in combat, it is known that soldier marksmanship noticeably decreases regardless of prior training. Active stabilization systems in small arms have potential to address this problem to increase soldier survivability and mission ...

Smart Materials and Structures, 2010

While shape memory alloys (SMAs) have many actuation benefits, their frequencies are commonly res... more While shape memory alloys (SMAs) have many actuation benefits, their frequencies are commonly restricted by slow cooling times caused by limitations in convective heat transfer. To increase the cooling speed and at the same time reduce excess power consumption from overheating, it is critical to understand the heat transfer from SMA wires. This requires accurate surface temperature measurement under a fixed input power, which is difficult to obtain using traditional methods because of the nature of SMAs (thin wires, large strains, heat activation, ambient environment, etc). This paper introduces a non-invasive technique for calculating the convective coefficient for SMAs by employing the temperature-induced transformation strain of SMAs to estimate the surface temperature. This method was experimentally validated for measurement of the convective coefficient in air where infrared cameras can operate, and then used to indirectly measure the convective coefficient across a range of commonly utilized SMA wire diameters and ambient media where traditional methods are limited. Formulated empirical correlations to the collected data provide a mathematical relationship to calculate the convective coefficient in material models which serve as better estimates of convection, and may be used for optimization of SMA actuators for increased frequency performance while ensuring that power draw is minimized.

Movement Disorders, 2013

We acknowledge the limitations of this study, with its open-label treatment and retrospective ana... more We acknowledge the limitations of this study, with its open-label treatment and retrospective analysis. However, the sustained self-reported improvements, together with partial waning of treatment at around 3 or 4 months in many patients, as well as the long-term treatment and follow-up in the majority of patients argue against placebo response being the only explanation for benefit. Conclusions Our data support the efficacy of BTX in the treatment of proximal tremor. Functionally meaningful improvements were observed in the majority of patients, and these results should be verified with a randomized, double-blind, placebo-controlled trial. Legends to the Videos Video Segment 1. This video demonstrates the position-dependent upper limb proximal tremor with internal-external rotatory component. Note that the tremor is maximal with the hands held in the nosetargeting position. The muscles injected were teres major (20 units), teres minor (20 units), pectoralis major (20 units), supraspinatus (10 units), infraspinatus (10 units), biceps (5 units). and triceps (5 units; total dose, 90 units). Video Segment 2. This is a video clip of the same patient in video segment 1, 5 weeks after botulinum toxin injections.

An apparatus for and method of conditioning a thermally activated shape memory alloy wire for use... more An apparatus for and method of conditioning a thermally activated shape memory alloy wire for use in an application, wherein the apparatus includes an adjustable hard-stop and the preferred method includes pre-determining a minimum activating current, allowable strain, and a loading magnitude and form based on the wire configuration and application, and further includes applying a double-exponential model to determine a final recoverable strain over fewer cycles.

Behavior and Mechanics of Multifunctional and Composite Materials 2008, 2008

A commonly noted disadvantage of shape memory alloys is their frequency response which is limited... more A commonly noted disadvantage of shape memory alloys is their frequency response which is limited by how fast the material can be cooled. This paper presents a feasibility study of using vertically aligned carbon nanotubes (CNT) as microscopic cooling fins to improve convective heat transfer. Using DC plasma enhanced chemical vapor deposition (PECVD), aligned CNT's were successfully grown directly on ½ of the surface of a 0.38 mm diameter SMA wire, achieving desirable thermal contact. Cooling speeds were measured with a thermal imaging camera, and the effective convective coefficient was extracted from the temperature profiles using a basic cooling model of the wire. From this model, the effective convective coefficient was estimated to have increased by 24% (from 50 W/m2K for untreated SMA wire to 62 W/m2K for the nanotube treated wire), indicating that the deposition of CNT's indeed increased performance. By extrapolating these results to full wire coverage, up to a 46% improvement in frequency response with zero weight or volumetric penalties is predicted. Further improvements in cooling performance are likely to occur with higher CNT densities and longer nanotube lengths, allowing further developments of this technology to benefit many future applications utilizing high-speed miniature/micro-scale SMA actuators.