Commercial Off-the-shelf Research Articles

Assessment of Reliability Allocation Methods for Electronic Systems: A Systematic and Bibliometric Analysis

Reliability allocation is the process of assigning reliability targets to sub-systems within a system to meet the overall reliability requirements. However, many traditional reliability allocation methods rely on assumptions that are often unrealistic, leading to misleading, unachievable, and costly outcomes. This paper provides a historical review of reliability allocation methods, focusing on the Weighing Factor Method (WFM), with a detailed analysis of its main findings, assumptions, and limitations. Additionally, the review covers methods for reliability optimization, redundancy optimization, and multi-state system optimization, highlighting their strengths and shortcomings. A case study is presented to demonstrate how the assumption of an exponential distribution impacts the reliability allocation process, showing the limitations it imposes on practical implementations. Furthermore, a bibliometric analysis is conducted to assess publication trends in the field of reliability allocation. Through examples, particularly in the context of electronic systems using commercial off-the-shelf (COTS) components, the challenges are discussed, and recommendations for alternative approaches to improve the reliability allocation process are provided.

Quantifying the Volume of Residual Air in Commercial Intravenous Fluids and Assessing the Stability of Airless Intravenous Fluid Containers.

Commercial off-the-shelf (COTS) intravenous fluid (IVF) containers contain residual air, introducing the risk of venous air embolism (VAE). Venous air embolism occurs when air displaces blood flow in vasculature. The danger from residual air is often negligible in terrestrial settings, where gravitational forces generate buoyancy, pushing residual air to the top of the IVF container. However, in microgravity there is no buoyancy to separate liquid and gas layers. We performed experiments to quantify the amount of air in COTS IVF containers (Experiment 1) and identify the variables that affect the stability of sterilely produced airless containers (Experiment 2). Experiment 1: Residual air was quantified across varying volumes (100, 250, 500, and 1,000 mL), container design, and manufacturer (B. Braun, Baxter, ICU Medical, and Grifols) of 0.9% NaCl COTS IVFs. Each container was assessed for absolute volumes of air, as well as air:fluid ratios normalized to 1,000 mL. Experiment 2: 1,000 mL IVF containers from 3 manufacturers were filled with either (1) 100% saline or (2) 95% saline and 5% air by volume. Containers were stored for 168 days at 25°C or 40 °C. The containers were optically imaged to quantify the accumulation of air within each IVF container. Experiment 1: There was a trend toward larger container sizes and greater absolute volumes of residual air (R2 = 0.964). However, the smallest air:volume ratio occurred in the Baxter 500 mL VIAFLO Container (18.9 ± 3.8 mL air; 2.3% air by volume), whereas the largest ratio occurred in the B. Braun 250 mL EXCEL Container (55.0 ± 9.3 mL; 22.0% air by volume). Experiment 2: By day 168, 6 experimental containers had ruptured and 100% of the surviving containers (30/36) had an increase in air as compared to baseline. Containers placed at 40 °C had a larger increase in air (27.7 ± 6.6 mL) compared to containers stored at 25 °C (7.5 ± 4.1 mL; P < .0001). Residual air has a wide variety of volumes in COTS IVFs. The average amount of residual air is high enough to contribute to clinically significant VAEs, although unlikely to be fatal. If airless IVF containers are produced for exploration missions, a progressive increase in the amount of residual air should be expected. Extremes of temperatures and humidity will increase the reaccumulation of residual air and decrease the shelf-life of airless IVFs.

Radiation and magnetic field qualification of LVPS — a unified 12V DC power source for the CMS detector

Efforts aiming at consolidating the powering for the CMS detector have led to the development of a Low Voltage Power Supply (LVPS). The LVPS converts 380 V DC to 12 V DC, suitable for powering the widely used bPOL12V point-of-load DC-DC converter. To limit cable size, the LVPS must be hosted in the CMS experimental cavern, being exposed to ionizing radiation and stray magnetic field of up to 120 mT. The device is made of Commercial Off-The-Shelf (COTS) components, therefore, thorough qualifications at various design stages were performed to ensure its reliable operation in the harsh environmental conditions for the HL-LHC era.

U-Flash: Improving Underwater Optical Communication by Scattering Effect

Underwater communication has been a focal point of communication research, driven by a multitude of applications including underwater facility maintenance and marine exploration. However, current systems often require expensive specialized equipment, rendering them less accessible. In this paper, we break the norm by pioneering the use of Commercial Off-The-Shelf (COTS) smartphones for underwater optical communication, leveraging their built-in flashlight and camera. Contrary to prevalent belief that scattering has a negative impact on communication, we discover that scattering in water can provide a positive gain for camera-based optical communication. Based on this insight, we present and implement U-Flash, a novel system encompassing a Fresnel lens plugin design to enhance light directionality and a tailored encoding-decoding scheme optimized for underwater environments. Comprehensive experiments demonstrate the effectiveness of U-Flash, achieving significant improvements in communication distance, reliability, and data rate. Specifically, the achievable communication distance is improved from 2.4 m to 7.6 m during daytime in the presence of strong ambient light interference and further extended to 9.8 m in low ambient light scenarios at night.

Expanded Linear Responsivity for Earth and Planetary Radiometry

Abstract Earth and planetary radiometry requires spectrally dependent observations spanning an expansive range in signal flux due to variability in celestial illumination, spectral albedo, and attenuation. Insufficient dynamic range inhibits contemporaneous measurements of dissimilar signal levels and restricts potential environments, time periods, target types, or spectral ranges that instruments observe. Next-generation (NG) advances in temporal, spectral, and spatial resolution also require further increases in detector sensitivity and dynamic range corresponding to increased sampling rate and decreased field of view (FOV), both of which capture greater intrapixel variability (i.e., variability within the spatial and temporal integration of a pixel observation). Optical detectors typically must support expansive linear radiometric responsivity, while simultaneously enduring the inherent stressors of field, airborne, or satellite deployment. Rationales for significantly improving radiometric observations of nominally dark targets are described herein, along with demonstrations of state-of-the-art (SOTA) capabilities and NG strategies for advancing SOTA. An evaluation of linear dynamic range and efficacy of optical data products is presented based on representative sampling scenarios. Low-illumination (twilight or total lunar eclipse) observations are demonstrated using a SOTA prototype. Finally, a ruggedized and miniaturized commercial-off-the-shelf (COTS) NG capability to obtain absolute radiometric observations spanning an expanded range in target brightness and illumination is presented. The presented NG technology combines a multipixel photon counter (MPPC) with a silicon photodetector (SiPD) to form a dyad optical sensing component supporting expansive dynamic range sensing, i.e., exceeding a nominal 10 decades in usable dynamic range documented for SOTA instruments.

High Sensitivity Long Pulse Envelope Detector Assisted by Microwave Photonics

This article presents a concept of a long pulse envelope detector (ED) with a high sensitivity value based on Microwave Photonics (MWP). The process of envelope detecting of RF signals is achieved by the translation of the RF spectrum to the optical spectrum range followed by optical filtering to cut the lower sideband and the carrier, finally beating the remaining upper sideband into a low-speed photodetector (LSPD). The LSPD output signal is amplified by transimpedance gain. This approach depends only on the RF passing band of the phase modulator (PM) and the optical filter transfer function. This concept is experimentally demonstrated reaching envelope detector tangential signal sensitivity (TSS) values around to -40 dBm for RF input frequency range from 10 GHz to 20 GHz. The proposed architecture does not use any optical or video signal amplifier. The implementation of this approach is simple, employs few components, and Commercial off-the-Shelf (COTS).

Identification of position, size and dynamic heat power of chips embedded in a real electronic board

Temperature is a critical factor in the lifespan of electronic systems. Therefore, it is essential to control all thermal parameters. In certain applications, such as commercial off-the-shelf (COTS) components, manufacturers may not have precise knowledge of the composition of electronic boards. As a result, it is important for them to define the positions of heat-dissipating elements, and the power dissipated to better predict the final thermal behavior of the system. Some electronic boards today even have components integrated into their volume. Since components can now be located not only on the surface but also within the volume of electronic boards, manufacturers need to define volume-based methods for detecting these heat sources. In this article, we address the problem of detecting sources within a volume using surface temperature data. To achieve this goal, we develop a representative numerical model of the system that can be used for an inverse source identification procedure. In a first time, we present a numerical approach that demonstrates the feasibility of the identification procedure on a board containing several electronic chips. Secondly, the volume source identification method is applied to a real case, using surfaces temperatures measured by infrared cameras. The experimental results obtained are consistent and show that this technique is suitable for detecting volumetric sources within an electronic board.

A Review of Techniques for Ageing Detection and Monitoring on Embedded Systems

Embedded digital devices are progressively deployed in dependable or safety-critical systems. These devices undergo significant hardware ageing, particularly in harsh environments. This increases their likelihood of failure. It is crucial to understand ageing processes and to detect hardware degradation early for guaranteeing system dependability. In this survey, we review the core ageing mechanisms, and identify and categorize general working principles of ageing detection and monitoring techniques for Commercial-Off-the-Shelf (COTS) components that are prevalent in embedded systems: Field Programmable Gate Arrays (FPGAs), microcontrollers, Systems-on-Chips (SoCs), and their power supplies. From our review, we find that online techniques are more widely applied on FPGAs than on other components, and see a rising trend towards machine learning application for analysing hardware ageing. Based on the reviewed literature, we identify research opportunities and potential directions of interest in the field. With this work, we intend to facilitate future research by systematically presenting all main approaches in a concise way.

Investigating commercially available force sensors for bone conduction hearing device evaluation

Bone conduction devices (BCDs) stimulate the auditory system by transmitting audio-frequency vibrations into the head. BCDs have long been used to diagnose and treat hearing loss, but increased interest in BCDs for consumer and communications applications has led to a proliferation of transducer designs. BCD calibration has historically been performed using an artificial mastoid, an expensive device that does not readily accommodate all BCD styles or account for impacts of anatomical variability on BCD coupling. Recent developments in force sensing technology could offer an inexpensive alternative to artificial mastoids for use with human subjects. Here, three commercial off-the-shelf (COTS) sensors were identified that met size, flexibility, and dynamic range requirements necessary for evaluating human BCD performance. Sensor accuracy and repeatability of both static and dynamic force measurements were compared against artificial mastoid measurements. A capacitance-based sensor successfully measured static force coupling but was incapable of capturing dynamic force output due to sensor bandwidth limitations. A piezoresistive sensor had a suitable bandwidth, but required significant signal conditioning to amplify signals and improve accuracy and precision. An alternative piezoresistive sensor utilized integrated circuitry to amplify signals, increasing sensor durability and accuracy. Future research will evaluate additional low-cost solutions for BCD evaluation.

AudioMove: Applying the Spatial Audio to Multi-Directional Limb Exercise Guidance

Guiding users with limb exercise can assist in muscle training or physical recovery. However, traditional vision-based methods often require multiple camera angles to help users understand the motions and require them to be within the range of the screen. Therefore, we propose a non-visual system that can guide users with multiple-directional limb motions utilizing spatial audio, AudioMove , with commercial-off-the-shelf (COTS) devices (i.e., smartphones and earphones). The proposed system addresses the challenge of conveying directional information encompassing multiple planes in real-time. We conduct a mixed-method user study to evaluate the effectiveness of the system with three methods combining motion data with spatial audio perception. Additionally, a user interface is built to collect users' comments. The results conclude that spatial audio guidance could create a natural, pervasive, and non-visual exercise training solution in daily life.

Total Ionizing Dose and Single-Event Effect Response of the AD524CDZ Instrumentation Amplifier

This manuscript focuses on studying the radiation response of the Commercial-off-the-shelf (COTS) AD524CDZ operational amplifier. Total Ionizing Dose (TID) effects were tested using low-dose 60Co irradiation. Single-Event Effect (SEE) sensitivity was studied on this operational amplifier using a 105 MeV proton beam. Additionally, further study of the SEE response was carried out using a Two-photon absorption laser to scan some sensitive sectors of the die. For this laser experiment, different gain setups and laser energies were employed to determine how the Single Event Transient (SET) response of the device was affected based on the test configuration. The results from the TID experiments revealed that the studied device remained functional after 100 krads (Si). Proton experiments revealed the studied device exhibited a high SET response with a maximum DC offset SET of about 1.5 V. Laser experiments demonstrated that there was a clear SET reduction when using 10× and 1000× gain setups.

Hardware Development and Evaluation of Multihop Cluster-Based Agricultural IoT Based on Bluetooth Low-Energy and LoRa Communication Technologies.

In this paper, we present the development and evaluation of a contextually relevant, cost-effective, multihop cluster-based agricultural Internet of Things (MCA-IoT) network. This network utilizes commercial off-the-shelf (COTS) Bluetooth Low-Energy (BLE) and LoRa communication technologies, along with the Raspberry Pi 3 Model B+ (RPi 3 B+), to address the challenges of climate change-induced global food insecurity in smart farming applications. Employing the lean engineering design approach, we initially implemented a centralized cluster-based agricultural IoT (CA-IoT) hardware testbed incorporating BLE, RPi 3 B+, STEMMA soil moisture sensors, UM25 m, and LoPy low-power Wi-Fi modules. This system was subsequently adapted and refined to assess the performance of the MCA-IoT network. This study offers a comprehensive reference on the novel, location-independent MCA-IoT technology, including detailed design and deployment insights for the agricultural IoT (Agri-IoT) community. The proposed solution demonstrated favorable performance in indoor and outdoor environments, particularly in water-stressed regions of Northern Ghana. Performance evaluations revealed that the MCA-IoT technology is easy to deploy and manage by users with limited expertise, is location-independent, robust, energy-efficient for battery operation, and scalable in terms of task and size, thereby providing a versatile range of measurements for future applications. Our results further demonstrated that the most effective approach to utilizing existing IoT-based communication technologies within a typical farming context in sub-Saharan Africa is to integrate them.

Transfer learning-accelerated network slice management for next generation services

The current trend in user services places an ever-growing demand for higher data rates, near-real-time latencies, and near-perfect quality of service. To meet such demands, fundamental changes were made to the traditional radio access network (RAN), introducing Open RAN (O-RAN). This new paradigm is based on a virtualized and intelligent RAN architecture. However, with the increased complexity of 5G applications, traditional application-specific placement techniques have reached a bottleneck. Our paper presents a Transfer Learning (TL) augmented Reinforcement Learning (RL) based networking slicing (NS) solution targeting more effective placement and improving downtime for prolonged slice deployments. To achieve this, we propose an approach based on creating a robust and dynamic repository of specialized RL agents and network slices geared towards popular user service types such as eMBB, URLLC, and mMTC. The proposed solution consists of a heuristic-controlled two-module-based ML Engine and a repository. The objective function is formulated to minimize the downtime incurred by the VNFs hosted on the commercial-off-the-shelf (COTS) servers. The performance of the proposed system is evaluated compared to traditional approaches using industry-standard 5G traffic datasets. The evaluation results show that the proposed solution consistently achieves lower downtime than the traditional algorithms.

From Do-It-Yourself Design to Discovery: A Comprehensive Approach to Hyperspectral Imaging from Drones

This paper presents an innovative, holistic, and comprehensive approach to drone-based imaging spectroscopy based on a small, cost-effective, and lightweight Unmanned Aerial Vehicle (UAV) payload intended for remote sensing applications. The payload comprises a push-broom imaging spectrometer built in-house with readily available Commercial Off-The-Shelf (COTS) components. This approach encompasses the entire process related to drone-based imaging spectroscopy, ranging from payload design, field operation, and data processing to the extraction of scientific data products from the collected data. This work focuses on generating directly georeferenced imaging spectroscopy datacubes using a Do-It-Yourself (DIY) imaging spectrometer, which is based on COTS components and freely available software and methods. The goal is to generate a remote sensing reflectance datacube that is suitable for retrieving chlorophyll-A (Chl-A) distributions as well as other properties of the ocean spectra. Direct georeferencing accuracy is determined by comparing landmarks in the directly georeferenced datacube to their true location. The quality of the remote sensing reflectance datacube is investigated by comparing the Chl-A distribution on various days with in situ measurements and satellite data products.

Reinforcement learning-based automated modulation switching algorithm for an enhanced underwater acoustic communication

Acoustic communication is the preferred method for underwater communication due to its superior propagation characteristics, including longer range, lower attenuation, better penetration, and adaptability to water density. However, challenges like varying water depths, temperature gradients, noise, and multipath propagation require innovative solutions beyond fixed-data rate systems and single modulation schemes. To address these challenges, we propose a reinforcement learning (RL)-based automated modulation switching algorithm designed to enhance data transmission efficiency. This approach leverages the UNETStack software and the Frequency Hopping-Binary Frequency Shift Key (FH-BFSK) modulation, extending its capabilities by incorporating Amplitude Shift Keying (ASK), Phase Shift Keying (PSK), and Orthogonal Frequency Division Multiplexing (OFDM) modulation techniques. We designed a cost-effective, software-controlled acoustic modem using commercial off-the-shelf (COTS) components, enabling full-duplex underwater communication. The RL algorithm utilizes a Q-matrix guided by a greedy policy to assess network conditions, such as data volume and data rates. It continuously monitors underwater environments to select the most suitable modulation scheme dynamically. Experimental validation demonstrates a 3.648 % improvement in Received Signal Strength Indicator (RSSI), a 32 % reduction in bit error rate at a constant 7 dB Signal-to-Noise Ratio (SNR), and a 5 % increase in utility at 10 dB SNR when using OFDM selected by the reinforcement learning algorithm, compared to FH-BFSK.

GrainSense: A Wireless Grain Moisture Sensing System Based on Wi-Fi Signals

Grain moisture sensing plays a critical role in ensuring grain quality and reducing grain losses. However, existing commercial off-the-shelf (COTS) grain moisture sensing systems are either expensive, inconvenient or inaccurate, which greatly limit their widespread deployment in real-world scenarios. To fill this gap, we develop a system called GrainSense which leverages COTS Wi-Fi devices to detect the grain moisture without the need for dedicated sensors. Specifically, we propose a wireless grain moisture detection model based on the refraction phenomenon of Wi-Fi signals and the Multiple-Input-Multiple-Output (MIMO) technology. On one hand, we correlate the grain moisture with the phase difference between two refracted Wi-Fi signals that propagate along different paths, based on which grain moisture can be deduced accordingly. On the other hand, to reduce the multi-path interference in indoor environments (e.g., the granary), we adopt Wi-Fi beamforming to enhance the refracted signal. In particular, a new signal feature (i.e., the Wi-Fi CSI beamforming ratio) is designed to eliminate the effect of sub-carrier frequency bias and cumulative phase bias. To validate the effectiveness of the developed system, we conduct extensive experiments with different types of grains in both the laboratory and the granary. Results show that the system can accurately estimate the grain moisture with an mean absolute error smaller than 5%, which meets the requirements for commercial usage. To the best of our knowledge, this is the first model-based work that achieves accurate grain moisture detection based on wireless sensing.

Off-the-shelf UHF RFID-based sensors for corrosion characterization of coated steel

The application of the UHF RFID technique in non-destructive testing (NDT) and structural health monitoring (SHM) has gained increasing attention due to its wireless, battery-less, and cost-effective attributes. It offers a promising approach for SHM and the Internet of Things (IoTs). This paper reports commercial off-the-shelf (COTS) flexible UHF RFID tag-based sensors for corrosion characterization on coated mild steel. Two types of COTS flexible UHF RFID tags with different bends are fabricated as sensors. The received signal strength indicator (RSSI) measurement is implemented to characterize the corrosion. Three parts (T-match area, dipole arms, and dipole loadings) of the two tags are tested for sensing purposes, and comparison and discussion of sensitivity, read range, and results are provided. This study successfully validates the feasibility of the proposed tag-bent method for corrosion characterization undercoating. It can be concluded that the dipole arm part of the applied COTS tags is the most sensitive area.

Technical and economic feasibility of a small vertical axis wind turbine in low wind conditions compared to other power sources for pumping water

In a global context, the significance of transitioning to renewable energy sources is paramount for sustainable development. This relevance is particularly evident in Brazil, where significant strides have been made in microgeneration of photovoltaic solar power and on-shore large-scale horizontal-axis wind power. Despite the country's extensive energy capacity from hydroelectric facilities, still approximately 38.5 million people reside in rural areas and surrounding areas, emphasizing the need for effective and affordable energy solutions for these regions. Based on this social and business opportunity of small-sized devices used in sustainable development, this practical experimentation explores the viability of initial studies from a prototyped small vertical-axis wind turbine (VAWT) system for water pumping, comparing its technical and economic feasibility with commercial off-the-shelf (COTS) photovoltaic solar pump (PV) and conventional electrical pump systems (EP). Two scenarios are investigated: (1) a patented transmission mechanism connected to a double effect pump and (2) the VAWT system designed to be connected to the same mechanism. Compared to PV ‘systems, scenario (1) offers 1.4x higher flowrate at a significantly lower cost (137% less) and consumes half the power. It offers a lower flowrate (2.6x) than EP systems but at a lower cost (36% less) and consumes one-third the power. Scenario (2) provides 2.7x less water flow than PV at a slightly lower cost (41% less). While less efficient in water flow (10 x) compared to EP, it has a slightly higher cost (15% more). This research builds upon existing knowledge and offers valuable insights for future small VAWT applications in low-wind remote areas for water pumping.

Technology modification, development, and demonstrations for future spaceflight medical systems at NASA

Throughout the history of human spaceflight, spacefarers have experienced and reported the occurrence of medical conditions, including various illnesses and injuries. Therefore, future spaceflight missions to the Moon and Mars will require the capabilities necessary for maintaining the health of these new space travelers. Mass, power, and volume available in the space vehicles used for these missions will be severely constrained. The ability to resupply or evacuate to Earth will be limited or non-existent, and ground-based support will no longer be immediate due to communication latencies and blackouts. These vehicle and mission constraints will necessitate healthcare be provided from an efficiently planned medical system. To provide the necessary care, these medical systems will need to include at a minimum, several different types of medical devices, consumable resources, centralized data management, procedural guidance, and decision support technologies. Medical devices needed for diagnosing and treating medical conditions that are expected to occur during future spaceflight missions may include real-time health monitoring, medical imaging capabilities, as well as blood and urine analysis. Novel methods for interacting with onboard patient medical records will be necessary, as will resource tracking. Terrestrial medicine shares many of these same needs, therefore a multitude of these required medical capabilities can likely be satisfied by currently available, Commercial-Off-The-Shelf (COTS) devices and methodologies; however, in some cases the unique space environment and increased mission durations will drive the need for modifications or customization of standard technologies and treatment procedures. This article will provide a review of medical devices and technologies that have been considered for inclusion within future spaceflight medical systems. It will also include a discussion about the modifications and customized development that have been performed, as well as descriptions of the technology demonstrations that have been conducted in analog and spaceflight environments.

Modelling Gd-diamond and Gd-SiC neutron detectors

A custom Monte Carlo (MC) computer model was developed to simulate thermal neutron absorption in, and subsequent photon and electron emission from, natural Gd with a view to using the material as a neutron conversion layer for neutron detectors. The MC code also modelled photon and electron detection with two dissimilar detectors: a thick (500 μm) single crystal diamond detector; and a thin (5.15 μm) commercial off the shelf (COTS) 4H–SiC photodiode detector. The detectors’ quantum detection efficiencies (QE) for hard X-rays and γ-rays were relatively low in comparison to their QE for electrons, thus making it possible to collect electron spectra from the Gd layer neutron conversion products which were not overwhelmed by photon emissions from the Gd. The MC code was utilised to determine the optimal thickness of Gd for the efficient detection of a thermal neutron flux. These radiation hard and spectroscopic detectors paired with natural Gd could find utility as robust and compact thermal neutron detectors for nuclear science and engineering, space science, and other applications.