A Wearable Device for Assisting Persons With Vision Impairment

Detecting humans and objects during walking has been a very difficult problem for people with visual impairment. To safely avoid collision with any object or human and to navigate from one location to another, it is significant to know how far and what kind of obstacle the user is facing. In recent years, many researches have shown that providing different vibration stimulation can be very useful to convey important information to the user. In this paper, we present our stereovision system with high definition camera to detect and identify humans and obstacles in real time and compare it with a modified version of existing wearable haptic belt that uses high-performance Ultrasonic sensors. The aim of this paper is to present the practicability of stereovision system over cane and assistive technology such as vibrotactile belt. The study is based on two assistive technologies. The first one consists of the vibrotactile belt connected to ultrasonic sensors and an accelerometer which returns user movement & speed information to the microcontroller. The microcontroller initiates expressive vibrotactile stimulation based on sensor data. Data gathered from this technology will be used as the baseline data for comparison with our stereovision system. Second, we present a novel approach to detect the type of obstacle using object recognition algorithm and the best approach to avoid it using the stereovision feedback. Data gathered from this technology with be comparted against the baseline data from the vibrotactile belt. In addition, we present the results of the comparative study which shows that stereovision system has plethora of advantages over vibrotactile belt.

Modular Prosthetic Design for Transtibial Child Amputees

Lower limb deficiencies and below knee amputations are the most common form of deficiency that may arise from disease or trauma, and returning a patient close to a normal quality-of-life requires prosthetics, which can be quite challenging. Children present even further difficulty to prosthetists and physicians than adults. Although the underlying prosthetic principles for adults are the same for children, additional considerations must be made for practicality, such as downsizing while maintaining its degree of complexity, and frequent appointments to account for the rapid growth of an adolescent. This review article will evaluate the current state-of-the-art in the field of transtibial-amputee prosthetics, review the insurance coverage a typical family would face, and suggest potential improvements to children’s biomimetic prostheses that aid in reducing the frequency of health care provider intervention.

Holographic Microwave Imaging for Breast Cancer Detection Based on Compressive Sensing

Microwave imaging (MI) has been considered as an alternative way to X-ray mammography for breast cancer detection. This paper presents a compressive sensing based holographic microwave imaging (CS-HMI) approach for diagnosing of breast cancer. A numerical imaging system is developed to validate the proposed CS-HMI approach, which includes a realistic human breast phantom and measurement model. Small breast tumour can be detected in the reconstructed CS-HMI image via Split Bregman (SB) with using 10% measurement data. Simulation and experimental results show that CS-HMI has the ability to produce high quality image by using significantly less measurement data and operation time.

POD Analysis of the Impact Dynamics of the Olive Tree Branch: Nature’s Paradigm of a Complex Soft-Stiff Structural System in Biomechanics

Geometry consistent spatio-temporal measurements of the experimental acceleration of olive tree branches were analyzed with advanced POD tools in an effort to gain knowledge on the mechanics-dynamics of this bio-mechanical structure. To pave the way for understanding the dynamics of this system, both the typical olive tree as a whole and its typical branch are approached as interacting soft-stiff continuum mechanical systems. The POD analysis reveals that the impact response is a nonlinear vibration with very fast dissipation. The POD modal amplitudes are nonlinear vibrations of continuous, broadband frequency spectrum. Initially they exhibit regular phases of nonlinear slow dissipation-and-amplification followed by irregular, fast dissipation-and-amplification phases. Sequentially applied impacts at the branch soft area results in a complete detachment of the fruit. The POD analysis reveals that this occurs because the response is highly localized in the soft area where the impact is applied and thus it transfers its momentum to the fruits. The work is supplemented with analysis of field measurements of the acceleration dynamics of orchard olive tree branches excited by harvesting devices generating combing clouds of impulsive forces aimed at detaching the olive fruit by momentum transfer.

Assistive Force Redirection of Crutch Gait Produced by the Kinetic Crutch Tip

This paper investigates how crutch tip designs affect the user’s gait. Five Kinetic Crutch Tips (KCT), each with different durometers (i.e., stiffnesses) along with one carbon fiber reinforced nylon 3D printed KCT and one Standard Rubber Tip were tested. The first experiment examined eight healthy subjects to determine the assistive horizontal force generated and crutch angle range. The second experiment eliminates the human factor and uses a weighted crutch in free fall to investigate transitional angles between forward and backward motions. It was found that the KCT had a larger transitional angle than the Standard Rubber Tip. This increases the assistive forward forces of the crutch due to the surface kinetic shape of KCTs; however, the total angle of different crutch tips remains the same when used by the subjects. The assistive forces were present for the longest amount of time for the highest durometer KCT.

Design and Control of an Assistive Bionic Joint for Leg Muscle Rehabilitation

This project aims to create an electronically powered and controlled knee brace to aid stroke victims with partial paralysis with their leg muscle rehabilitation process. The newly designed assistive bionic joint takes the functionality of the existing assistive knee braces to the next level by incorporating a control algorithm that uses sensor signals gathered from the patient’s leg muscles. Electromyography (EMG) is used for gathering impulse signals from electrodes placed on key muscles as inputs for the device. The action of each major leg muscle is replicated using a set of fluidic muscles that mimic the functionality of the actual leg muscles. A microcontroller is used to interpret sensor data and adjust the contraction length of the muscles, thereby providing the wearer with augmented strength and mobility. Initial testing of a proof-of-concept prototype has led to finite control over muscle contraction length based on sensor data and has a response time of 280ms from full extension to contraction. Further testing of the brace assembly, fluidic muscles and control system is conducted and the results indicate a 600ms response time due to a step input. This personalized, powered brace has many implications for the enrichment of muscle rehabilitation such as higher patient morale, more muscle activity, and shortened recovery times.

Evaluation of Pulmonary Arterial Hypertension Using Computational Fluid Dynamics Simulation

In silico study of the relationships between flow conditions, arterial surface shear stress, and pressure was investigated in a patient with pulmonary arterial hypertension (PAH), using multi-detector Computed Tomography Angiography (CTA) images and Computational Fluid Dynamics (CFD). The CTA images were converted into 3D models and transferred to CFD software for simulations, allowing for patient-specific comparisons between in silico results with clinical right heart catheterization pressure data. The simulations were performed using two different methods of outlet boundary conditions: zero traction and lumped parameter model (LPM) methods. Outlet pressures were set to a constant value in zero traction method, which can produce flow characteristics solely based on the segmented distal arteries, while the lumped parameter model used a three-element Windkessel lumped model to represent the distal vasculature by accounting for resistance, compliance, and impedance of the vasculature. Considering existing limitations with both approaches, it was found that the lumped parameter Windkessel outlet boundary condition provides a better correlation with the clinical RHC pressure results than the zero traction constant pressure outlet boundary condition.

Determination of a Pressure Drop in the Arteriovenous Fistula With Fluid Structure Interaction Simulations and In Vitro Methods

A pressure drop and its oscillations occurring in the arteriovenous fistula due to sudden changes in the velocity vector direction or the transitional or turbulent flow, related to its complicated geometry, can exert a significant impact on the blood vessel wall behaviour. On the other hand, the pressure drop cannot be precisely measured in vivo with non-invasive measurement methods. The aim of this study is to assess the pressure drop with numerical and experimental methods in the patient-specific fistula model taking into account a pulsating nature of the flow and the elasticity of blood vessel walls. An additional target is to find a correlation between these two methods. FSI and in vitro simulations of the blood flow were performed for a patient-specific model of the fistula. Basic geometrical data of the correctly functioning mature fistula were obtained with angio-computed tomography. Those data were applied to develop a spatial CAD model of the fistula, which allowed for creating a virtual model for computer simulations and an analogous in vitro model made with rapid prototyping techniques. The material used to build the in vitro model is characterised by mechanical properties similar to the arterial tissue. A non-stationary computer simulation was carried out with an ANSYS software package, keeping as many flow similarities to the experiments carried out on the test stand as possible, and where the blood mimicking fluid was a water solution of glycerine. During the experiments, the static pressure was measured downstream and upstream of the anastomosis with precise pressure transducers. The pressure drop was determined with the numerical and experimental methods, which take into account the elasticity of blood vessels. This is a novel approach, since most of similar studies were conducted on the assumption of rigid blood vessel walls. The obtained results show that the pressure drop within the fistula is not so high as reported in the literature, which is correlated with the precision of measurement methods and the fact that a large portion of the fluid energy is accumulated by the elastic walls.

Speech Assistance for Persons With Speech Impediments Using Artificial Neural Networks

This work focuses on the research related to enabling individuals with speech impairment to use speech-to-text software to recognize and dictate their speech. Automatic Speech Recognition (ASR) tends to be a challenging problem for researchers because of the wide range of speech variability. Some of the variabilities include different accents, pronunciations, speeds, volumes, etc. It is very difficult to train an end-to-end speech recognition model on data with speech impediment due to the lack of large enough datasets, and the difficulty of generalizing a speech disorder pattern on all users with speech impediments. This work highlights the different techniques used in deep learning to achieve ASR and how it can be modified to recognize and dictate speech from individuals with speech impediments.

Buckling Analysis of a Functionally Graded Implant Model for Treatment of Bone Fractures: A Numerical Study

In orthopedics, the current internal fixations often use screws or intramedullary rods that obstruct bone material. In this paper, an internal implant was modelled as a hollow cylindrical sector made of a functionally graded material (FGM), which will hold bone in place with less obstruction of bone surface. Functionally graded implant was considered as an inhomogeneous composite structure, with continuously compositional variation from a ceramic at the outer diameter to a metal at the inner diameter. The buckling behavior of the implant was numerically analyzed using a finite element analysis software (ANSYS), and the structural stability of the implant was assessed. The buckling critical loads were calculated for different fixation lengths, cross sectional areas, and different sector angles. These critical loads were then compared with the critical loads of an FGM hollow cylinder with the same cross sectional area. Results showed that the critical load of the hollow cylindrical sector was ∼ 63%, ∼ 70%, and ∼ 73% of the hollow cylinder for different fixation lengths, cross sectional areas, and sector angles, respectively. Further investigations are warranted to study the relation between the composition profile and the implant stability, which can lead to batter internal fixation solutions.