Unreliability Of Devices Research Articles

A Voice App Design for Heart Failure Self-management: Proof-of-Concept Implementation Study.

Voice user interfaces are becoming more prevalent in health care and are commonly being used for patient engagement. There is a growing interest in identifying the potential this form of interface has on patient engagement with digital therapeutics (DTx) in chronic disease management. Making DTx accessible through an alternative interaction model also has the potential to better meet the needs of some patients, such as older adults and those with physical and cognitive impairments, based on existing research. This study aimed to evaluate how participants with heart failure interacted with a voice app version of a DTx, Medly, through a proof-of-concept implementation study design. The objective was to understand whether the voice app would enable the participants to successfully interact with the DTx, with a focus on acceptability and feasibility. A mixed methods concurrent triangulation design was used to better understand the acceptability and feasibility of the use of the Medly voice app with the study participants (N=20) over a 4-week period. Quantitative data included engagement levels, accuracy rates, and questionnaires, which were analyzed using descriptive statistics. Qualitative data included semistructured interviews and were analyzed using a qualitative descriptive approach. The overall average engagement level was 73% (SD 9.5%), with a 14% decline between results of weeks 1 and 4. The biggest difference was between the average engagement levels of the oldest and youngest demographics, 84% and 43%, respectively, but these results were not significant-Kruskal-Wallis test, H(2)=3.8 (P=.14). The Medly voice app had an overall accuracy rate of 97.8% and was successful in sending data to the clinic. From an acceptability perspective, the voice app was ranked in the 80th percentile, and overall, the users felt that the voice app was not a lot of work (average of 2.1 on a 7-point Likert scale). However, the overall average score for whether users would use it in the future declined by 13%. Thematic analysis revealed the following: the theme feasibility of clinical integration had 2 subthemes, namely users adapted to the voice app's conversational style and device unreliability, and the theme voice app acceptability had 3 subthemes, namely the device integrated well within household and users' lives, users blamed themselves when problems arose with the voice app, and voice app was missing specific, desirable user features. In conclusion, participants were largely successful in using the Medly voice app despite some of the barriers faced, proving that an app such as this could be feasible to be deployed in the clinic. Our data begin to piece together the patient profile this technology may be most suitable for, namely those who are older, have flexible schedules, are confident in using technology, and are experiencing other medical conditions.

Overcoming device unreliability with continuous learning in a population coding based computing system.

The brain, which uses redundancy and continuous learning to overcome the unreliability of its components, provides a promising path to building computing systems that are robust to the unreliability of their constituent nanodevices. In this work, we illustrate this path by a computing system based on population coding with magnetic tunnel junctions that implement both neurons and synaptic weights. We show that equipping such a system with continuous learning enables it to recover from the loss of neurons and makes it possible to use unreliable synaptic weights (i.e. low energy barrier magnetic memories). There is a tradeoff between power consumption and precision because low energy barrier memories consume less energy than high barrier ones. For a given precision, there is an optimal number of neurons and an optimal energy barrier for the weights that leads to minimum power consumption.

Mechanical and Biological Interactions of Implants with the Brain and Their Impact on Implant Design.

Neural prostheses have already a long history and yet the cochlear implant remains the only success story about a longterm sensory function restoration. On the other hand, neural implants for deep brain stimulation are gaining acceptance for variety of disorders including Parkinsons disease and obsessive-compulsive disorder. It is anticipated that the progress in the field has been hampered by a combination of technological and biological factors, such as the limited understanding of the longterm behavior of implants, unreliability of devices, biocompatibility of the implants among others. While the field's understanding of the cell biology of interactions at the biotic-abiotic interface has improved, relatively little attention has been paid on the mechanical factors (stress, strain), and hence on the geometry that can modulate it. This focused review summarizes the recent progress in the understanding of the mechanisms of mechanical interaction between the implants and the brain. The review gives an overview of the factors by which the implants interact acutely and chronically with the tissue: blood-brain barrier (BBB) breach, vascular damage, micromotions, diffusion etc. We propose some design constraints to be considered in future studies. Aspects of the chronic cell-implant interaction will be discussed in view of the chronic local inflammation and the ways of modulating it.

DCC: A Dependable Cache Coherence Multicore Architecture

Cache coherence lies at the core of functionally-correct operation of shared memory multicores. Traditional directory-based hardware coherence protocols scale to large core counts, but they incorporate complex logic and directories to track coherence states. Technology scaling has reached miniaturization levels where manufacturing imperfections, device unreliability and occurrence of hard errors pose a serious dependability challenge. Broken or degraded functionality of the coherence protocol can lead to a non-operational processor or user visible performance loss. In this paper, we propose a dependable cache coherence architecture (DCC) that combines the traditional directory protocol with a novel execution-migration-based architecture to ensure dependability that is transparent to the programmer. Our architecturally redundant execution migration architecture only permits one copy of data to be cached anywhere in the processor: when a thread accesses an address not locally cached on the core it is executing on, it migrates to the appropriate core and continues execution there. Both coherence mechanisms can co-exist in the DCC architecture and we present architectural extensions to seamlessly transition between the directory and execution migration protocols.

Relax

As technology scales ever further, device unreliability is creating excessive complexity for hardware to maintain the illusion of perfect operation. In this paper, we consider whether exposing hardware fault information to software and allowing software to control fault recovery simplifies hardware design and helps technology scaling. The combination of emerging applications and emerging many-core architectures makes software recovery a viable alternative to hardware-based fault recovery. Emerging applications tend to have few I/O and memory side-effects , which limits the amount of information that needs checkpointing, and they allow discarding individual sub-computations with small qualitative impact. Software recovery can harness these properties in ways that hardware recovery cannot. We describe Relax, an architectural framework for software recovery of hardware faults. Relax includes three core components: (1) an ISA extension that allows software to mark regions of code for software recovery, (2) a hardware organization that simplifies reliability considerations and provides energy efficiency with hardware recovery support removed, and (3) software support for compilers and programmers to utilize the Relax ISA. Applying Relax to counter the effects of process variation, our results show a 20% energy efficiency improvement for PARSEC applications with only minimal source code changes and simpler hardware.

Evaluation of the IITC tail cuff blood pressure recorder in the rat against intraarterial pressure according to criteria for human devices

National standards govern the manufacture and marketing of medical devices in the United States, including those for indirect blood pressure measurement in man. There are no comparable standards for devices for recording in laboratory animals. Noninvasive tail cuff blood pressure (BP) recording in the rat is widely accepted, but beset by methodologic difficulties. Intraarterial recording is regarded as the “gold standard” but is invasive and also susceptible to methodologic error. We compared the IITC Mark 12 photoelectric/oscillometric tail cuff system (IITC Life Sciences, Woodland Hills, CA) versus simultaneous femoral intraarterial recordings in spontaneously hypertensive rats, during anesthesia and 1 to 2 days after recovery (150 recordings under each condition), according to the guidelines for human data collection and analysis suggested by the American National Standard for automated sphygmomanometers. Within- and between-observer disagreements in estimates made by two observers from 40 anesthetized recordings were less for intraarterial measurements than for the tail cuff method. Within-observer differences (mean ± SD of differences [SDD]) for systolic, diastolic, and mean pressure were 0 ± 1, 0 ± 1, and 0 ± 1 mm Hg for intraarterial versus −1 ± 3, 0 ± 8, and 0 ± 5 mm Hg for tail cuff. Between-observer differences were 0 ± 2, 0 ± 1, and 6 ± 2 mm Hg versus 5 ± 4, 13 ± 7, and 0 ± 5 mm Hg, respectively. Differences between tail cuff and intraarterial methods were 16 ± 13, −5 ± 11, and 2 ± 8 mm Hg in anesthetized animals and 8 ± 14, −5 ± 9, and 0 ± 9 mm Hg in conscious animals (39% to 82% of differences exceeded 5 mm Hg). The upper limits of clinically acceptable disagreement in the American National Standard are: mean of 5 mm Hg, SDD of 8 mm Hg. The disagreement between tail cuff and intraarterial recordings cannot be ascribed to either method with certainty. These findings do not support the manufacturer's guarantee of tail-cuff readings within “5 mm Hg of intraarterial.” Inaccuracy and unreliability of devices intended for laboratory animal use have considerable scientific, fiscal, and ethical implications. Marketing of these devices should also be governed by rigorous standards.