Commercial Off-the-shelf Research Articles

Nested Miller Compensation Based Op-Amp Design for Piezoelectric Actuators

This study introduces the design of a practical three-stage operational amplifier (op-amp) using nested Miller compensation, particularly for piezoelectric actuators. Driving a piezoelectric actuator represents a challenge in amplifier design due to its large capacitive nature. A stable piezo driver needs to be free of oscillations and phase lag. Direct feedback compensation using a conventional Miller capacitor is an effective method as long as the capacitance of the load is considerably close to the value of the Miller capacitor. However, using a large capacitor causes a decrease in the slew rate and gain bandwidth. To avoid this, our design focused on the utilization of nested Miller compensation technique. A prototype of the design working at 100V peak to peak voltage (Vpp) is implemented using commercial off-the-shelf (COTS) components. The measurements show the successful driving capability and step-response of the op-amp design. In the design, Widlar current source is also utilized for thermal stability and short circuit protection. According to simulation results, the proposed op-amp has a slew rate of 0.5 V/μs, an open loop gain of 90dB with 3MHz Gain Bandwidth Product (GBP) and phase margin of 77°, and a common mode rejection ratio (CMRR) of 62dB.

A Mixed-Signal Adaptive Ripple Canceler for Switching Regulators Providing 18 dB-24 dB of Ripple Rejection up to 1 MHz

A mixed-signal adaptive ripple canceller for reducing switching noise and spurious emissions in switching regulators is presented. The proposed mixed-signal ripple suppression technique tracks and cancels the switching noise by utilizing two schemes: A primary mixed-signal adaptive ripple canceller that provides large signal ripple cancellation up to 20 dB, and an auxiliary linear amplifier-based ripple canceller that minimizes the residual ripple content, achieving a combined ripple rejection of 24 dB. Proposed approach operates without the need for external components, reducing overall printed circuit board area without loss of efficiency. The adaptive ripple canceller is designed and fabricated in a 250 nm CMOS process with four levels of metal. The ripple-canceller is integrated with an on-chip buck regulator to characterize its rejection effectiveness. The ripple canceller can also be utilized as a stand-alone ripple cleaner module with an external commercial-off-the-shelf (COTS) switching regulator. The proposed ripple canceller can track and cancel power supply ripple up to 1 MHz with 24 dB rejection and reduces ripple content up to fourth harmonic by at least 20 dB while supporting dc loads up to 1 A and ripple currents up to 350 mApk-pk. The proposed approach achieves 30% lower quiescent current than using a linear low-dropout regulator without the need for any external components.

ACD: An Adaptable Approach for RFID Cloning Attack Detection.

With the rapid development of the internet of things, radio frequency identification (RFID) technology plays an important role in various fields. However, RFID systems are vulnerable to cloning attacks. This is the fabrication of one or more replicas of a genuine tag, which behave exactly as a genuine tag and fool the reader to gain legal authorization, leading to potential financial loss or reputation damage. Many advanced solutions have been proposed to combat cloning attacks, but they require extra hardware resources, or they cannot detect a clone tag in time. In this article, we make a fresh attempt to counterattack tag cloning based on spatiotemporal collisions. We propose adaptable clone detection (ACD), which can intuitively and accurately display the positions of abnormal tags in real time. It uses commercial off-the-shelf (COTS) RFID devices without extra hardware resources. We evaluate its performance in practice, and the results confirm its success at detecting cloning attacks. The average accuracy can reach 98.7%, and the recall rate can reach 96%. Extensive experiments show that it can adapt to a variety of RFID application scenarios.

First Hardware Implementation of an SSK MIMO System With no RF-Chain at the Transmitter

This article presents the hardware implementation of a space shift keying (SSK) multiple-input multiple-output (MIMO) system with no radio frequency (RF)-chain at the transmitter. The transmitter design was solely based on RF-switches. SSK relays information strictly through spatial symbols and does not require the generation of any modulated symbol. It has been always anticipated in literature that SSK can be implemented with a single or no RF chain, but the physical realizations were never accomplished. This work demonstrates a 4 × 2 and 2 × 2 MIMO implementation of an SSK system using commercial-off-the-shelf (COTS) RF-switches. As a result, the achieved implementation paves the way towards commercial deployments of space modulation techniques. A detailed discussion of the hardware implementation is presented and results reveal an accurate match with theoretical SSK results over a Rician fading channel with variant Rician K- factors.

NotchPUF: Printed Circuit Board PUF Based on Microstrip Notch Filter

Physical Unclonable Functions (PUFs) are primitives that are designed to leverage naturally occurring variations to produce a random bitstring. Current PUF designs are typically implemented in silicon or utilize variations found in commercial off-the-shelf (COTS) parts. Because of this, existing designs are insufficient for the authentication of Printed Circuit Boards (PCBs). In this paper, we propose a novel PUF design that leverages board variations in a manufactured PCB to generate unique and stable IDs for each PCB. In particular, a single copper trace is used as a source of randomness for bitstring generation. The trace connects three notch filter structures in series, each of which is designed to reject specific but separate frequencies. The bitstrings generated using data measured from a set of PCBs are analyzed using statistical tests to illustrate that high levels of uniqueness and randomness are achievable.

TagBreathe: Monitor Breathing with Commodity RFID Systems

Breath monitoring helps assess the general personal health and gives clues to chronic diseases. Yet, current breath monitoring technologies are inconvenient and intrusive. For instance, typical breath monitoring devices need to attach nasal probes or chest bands to users. Wireless sensing technologies have been applied to monitor breathing using radio waves without physical contact. Those wireless sensing technologies however require customized radios which are not readily available. More importantly, due to interference, such technologies do not work well with multiple users. When multiple users are present, the detection accuracy of existing systems decreases dramatically. In this paper, we propose to monitor users’ breathing using commercial-off-the-shelf (COTS) RFID systems. In our system, passive lightweight RFID tags are attached to users’ clothes and backscatter radio waves, and commodity RFID readers report low level data (e.g., phase values). We reliably detect the effective human respiration corresponded signal and track periodic body movement due to inhaling and exhaling by analyzing the low level data reported by commodity readers. To enhance the measurement robustness, we synthesize data streams from an array of multiple tags to improve the monitoring accuracy. Our design follows the standard EPC protocol which arbitrates collisions in the presence of multiple tags. We implement a prototype for the breath monitoring system with commodity RFID systems. The experiment results show that the prototype system can simultaneously monitor breathing with high accuracy even with the presence of multiple users.

The INSPIRE-2 CubeSat for the QB50 Project

The 2-unit CubeSat INSPIRE-2/AU03 was designed, built, tested, delivered, and accepted by the European Union’s QB50 project in less than 10 months and for less than US$120,000 in non-salary outlays including launch, despite being a first satellite. It carried 5 instruments (a multi-Needle Langmuir Probe, a diffraction-limited spectrograph, an advanced GPS receiver, and 2 radiation detectors) and the satellite hardware included both Commercial Off-The-Shelf (COTS) and Australian components. INSPIRE-2 was deployed into space from the International Space Station by Nanoracks on 26 May 2017 following an Atlas V launch. The satellite was brought online a month after launch as a result of a major campaign with the international radio amateur community. The uplink function of the Communications board was badly damaged in July 2017 in the first of that year’s two major, extended, space weather periods, plausibly due to radiation damage. While INSPIRE-2’s radio beacons were resurrected and continued for over a year the Communications board’s handshaking protocols meant that downlinking of data was not possible. INSPIRE-2 lived for over a year in space with mostly functioning systems. This paper summarises the major firsts and importance of INSPIRE-2 and its fellow Australian QB50 CubeSats UNSW-EC0 and SuSat (e.g., the first Australian CubeSats and the first Australian-built satellites in 16 years), as well as the science and technical goals, instruments, spacecraft systems, recovery, initial data, and evidence that the major space weather events of 12 July - 4 August 2017 significantly damaged INSPIRE-2 and caused an outage from 26 July to 5 September 2017. It also discusses the lessons learned and the reasons why CubeSats in constellations like QB50, whether international or Australian, provide excellent opportunities for scientific, technical, and commercial development, public outreach and engagement, and international engagement.

Design and Power Management of a Secured Wireless Sensor System for Salton Sea Environmental Monitoring

An embedded system composed of commercial off the shelf (COTS) peripherals and microcontroller. The system will collect environmental data for Salton Sea, Imperial Valley, California in order to understand the development of environmental and health hazards. Power analysis of each system features (i.e. Central Processing Unit (CPU) core, Input/Output (I/O) buses, and peripheral (temperature, humidity, and optical dust sensor) are studied. Software-based power optimization utilizes the power information with hardware-assisted power gating to control system features. The control of these features extends system uptime in a field deployed finite energy scenario. The proposed power optimization algorithm can collect more data by increasing system up time when compared to a Low Power Energy Aware Processing (LEAP) approach. Lastly, the 128 bit Advanced Encryption Standard (AES) algorithm is applied on the collected data using various parameters. A hidden peripheral requirement that must be considered during design are also noted to impact the efficacy of this method.

Multi-Adversarial In-Car Activity Recognition Using RFIDs

In-car human activity recognition opens a new opportunity toward intelligent driving behavior detection and touchless human-car interaction. Among the many sensing technologies (e.g., using cameras and wearable sensors), radio frequency identification (RFID) exhibits unique advantages given its low cost, easy deployment, and less privacy concerns. Existing RFID-based solutions for activity recognition are mostly confined to working in stable indoor spaces. The inside space of a car however is much more compact and complex, not to mention the fast-changing driving conditions. All these introduce non-negligible noises that pollute the activity-related information, and the existence of various car models in the market further complicates the problem. In this article, we for the first time closely examine the distinct factors that affect the RFID-based in-car activity recognition. We present RF-CAR, a novel RFID-based tag-free solution that well adapts to different in-car environments. RF-CAR smartly filters the domain-specific features in RF signals and retains activity-related features to the maximum extent. It then integrates a deep learning architecture and an advanced multi-adversarial domain adaptation network for training and prediction. With only one-time pre-training, RF-CAR can adapt to new data domains such as new driving conditions, car models, and human subjects for robust activity recognition. We also demonstrate that it is readily deployable in cars with commercial off-the-shelf (COTS) RFID devices. Our extensive experiments suggest that RF-CAR achieves an overall recognition accuracy of around 95 percent, which significantly outperforms the state-of-the-art solutions.

Data prefetch for fast NDN software routers based on hash table-based forwarding tables

The goal of the paper is to present the ideal form of an NDN forwarding engine on a commercial off-the-shelf (COTS) computer. In this paper, we design a reference forwarding engine by selecting well-established high-speed techniques and then analyze a state-of-the-art prototype implementation to identify its performance bottleneck. The microarchitectural analysis at the level of CPU pipelines and instructions reveals that dynamic random access memory (DRAM) access latency is one of bottlenecks for high-speed forwarding engines. Based on the analysis result, we design two prefetch-friendly packet processing techniques to hide DRAM access latency. The prototype employing the techniques achieves a forwarding rate exceeding 40 million packets per second on a COTS computer.

Process of Measuring the Maintainability of Commercial Off-the-Shelf (COTS) Based Systems: A Complexity Approach

This paper defines a process of predictive approach to evaluate the maintainability of a Commercial Off-the-Shelf (COTS)-based system(CBS) by analyzing the complexity of the deployment of the system. The approach integrates architectural dependencies and the system’s concept of operations to derive a network-based representation of the software system. A greater understanding of the deployment complexity is gained by using a Design Structure Matrix (DSM) to determine the number of architectural dependencies on a COTS product, or in-degree, for each COTS product in the system. The arithmetic mean of the in-degree for all nodes in the system is then compared with the perceived effort to maintain the system. The resultant measure – the in-degree mean – is useful in evaluating the maintainability of the operational system while the system is being designed and throughout its lifetime. Architects can use the approach to assist in COTS product selection and to make product trades to optimize the maintainability of the system. Integrators can use the approach to optimize product deployment and to determine the upgrade strategy for deployment. Finally, maintenance engineers can use the approach to estimate the effort required to maintain the system and to identify areas in which extensive product expertise is required. Because the approach requires only basic information about the system, it can be applied early in the design process and used until the system is decommissioned.

Experimental Evaluation and Characterization of Radioactive Source Effects on Robot Visual Localization and Mapping

Robots are ideally suited to performing simple tasks in dangerous environments. In this letter, we address the use of robots for inspection of nuclear reactors which may be contaminated by radiation. The geometry of a reactor vessel is three-dimensional with significant clutter. Accordingly, we propose the use of small-scale, flying robots that are able to localize themselves and autonomously navigate around obstacles. Because of the constraints on size, we rely on cameras which are the best low power and lightweight sensors. However, cameras perform poorly in the presence of radioactivity and the impact of radiation on robotics systems is not well understood. In this letter, we (a) analyze the effects of radioactive sources on camera sensors, affecting localization and mapping algorithms, (b) quantify these effects from a statistical viewpoint according to different source intensities; and (c) compare different solutions to mitigate these effects. Our analysis is supported and validated by experimental data collected on a Commercial-Off-The-Shelf (COTS) camera sensor exposed to radioactive sources in a hot cell.

Wireless Photoplethysmography Sensor for Continuous Blood Pressure Biosignal Shape Acquisition

Blood pressure assessment plays a vital role in day-to-day clinical diagnosis procedures as well as personal monitoring. Thus, blood pressure monitoring devices must afford convenience and be easy to use with no side effects on the user. This paper presents a compact, economical, power-efficient, and convenient wireless plethysmography sensor for real-time blood pressure biosignal monitoring. The proposed sensor facilitates blood pressure signal shape sensing, signal conditioning, and data conversion as well as its wireless transmission to a monitoring terminal. Received data can, subsequently, be compiled and stored on a computer via a Wi-Fi module. During monitoring, users can observe blood pressure signals being processed and displayed on the graphical user interface (GUI)—developed using a virtual instrumentation (VI) application. The proposed device comprises a finger clip optical pulse sensor, analogue signal preprocessing, microcontroller, and Wi-Fi module. It consumes approximately 500 mW power when operating in the active mode and synthesized using commercial off-the-shelf (COTS) components. Experimental results reveal that the proposed device is reliable and facilitates efficient blood pressure monitoring. The proposed wireless photoplethysmographic (PPG) sensor is a preliminary (or first) version of the intended device manifestation. It provides raw blood pressure data for further classification. Additionally, the collected data concerning the blood pressure wave shape can be easily analysed for use in other biosignal observations, interpretations, and investigations. The design approach also allows the device to be built into a wearable system for further research purposes.

The Accessibility of Commercial Off-The-Shelf Virtual Reality for Low Vision Users: A Macular Degeneration Case Study.

Virtual reality (VR) is demonstrating increasing potential for therapeutic benefit in elderly care, but it is still generally considered to be the domain of the visually unimpaired. Even where VR and augmented reality (AR) are being explored for use with low vision, it is generally with a focus on creating bespoke software and hardware. However, the properties of commercial off-the-shelf (COTS) headsets, such as high luminance, may render them accessible even to very low vision users. Using a case-study approach, we explored the differences in visual perception from baseline to pass-through AR and commercial VR applications for an elderly female (Mrs. M) with advanced age-related macular degeneration. We found notable improvements in object, face, and color recognition, particularly with higher display brightness. Furthermore, Mrs. M was able to engage fully and enthusiastically with a number of (unmodified) VR applications, providing detailed descriptions of both static and moving elements. We suggest that the high luminance available in COTS VR may support more stable fixation closer to the fovea, improving visual resolution. Furthermore, the improvements we noted in color perception support previous suggestions that increasing luminance may improve photosensitivity by reducing the uptake of limited oxygen by the rod cells. We conclude that low vision should not automatically preclude users from engaging in VR research or entertainment, and that they may be able to use well-illuminated VR applications without any special modifications.

Identification and Confirmation of Fentanyls on Paper using Portable Surface Enhanced Raman Spectroscopy and Paper Spray Ionization Mass Spectrometry

Fentanyl and its analogues play a major role in the current opioid epidemic. In particular, these highly potent opioids have become a health hazard due to their use as additives in street drugs. Consequently, rapid on-site procedures for the analysis of this class of seized drugs are needed, especially considering the reported backlog of drug samples, which must undergo identification and confirmation tests to validate the presence of an illicit substance. Paper based devices are cheap sampling and analysis vehicles that have been shown capable of allowing rapid identification and confirmation of drugs of abuse. Modifying paper substrates by imprinting nanoparticles enables surface enhanced Raman spectroscopy (SERS) as well as a second analysis from the same substrate, namely paper spray ionization mass spectrometry. While such a procedure has been described for laboratory use, these illicit drug samples are typically collected in the field and this is where testing should be done. We combine paper SERS and paper spray MS on field-portable and commercial off-the-shelf (COTS) devices for the rapid and low-cost identification and confirmation of fentanyl and its analogues, enabling in situ analysis at the point of seizure of suspect samples. The commercial nature of both instruments moves this technology from the academic realm to a setting where the criminal justice system can realistically utilize it. The capabilities of this single-substrate dual-analyzer technique are further examined by sampling a variety of surfaces of forensic interest.

Thermal-optical design of a geodetic satellite for one millimeter accuracy

The LAGEOS (LAser GEOdynamic Satellite) satellites use a 1.5 in. uncoated retroreflector (cube corner). Design studies done for LAGEOS-1 showed that using smaller cubes would result in greater accuracy and lower thermal gradients. However, this would require using a larger number of cubes. Simulations showed that the accuracy goal of 5 mm could be met using 1.5 in. cubes by adding a dihedral angle offset. The LARES (LAser RElativity Satellite) satellite launched in 2012 is a smaller version of LAGEOS using the same size cube corner and floating mount as LAGEOS.The recent development of COTS (Commercial Off-The-Shelf) cube corners has eliminated cost as an obstacle to using a larger number of smaller cubes. COTS cubes have no dihedral angle offset. However, no offset is needed if the size is chosen properly. The diffraction pattern of a 1.0 in. uncoated cube with no dihedral angle offset has 6 lobes around the central peak due to total internal reflection, The velocity aberration for LAGEOS is about 32–40 microradians. The OCS (Optical Cross Section) of a one inch uncoated COTS retroreflector is about 0.5 million sq m for the LAGEOS orbit.Testing of 10 inexpensive COTS cubes by Ludwig Grunwaldt and Reinhart Neubert shows good cross section (unpublished work done at GFZ Potsdam, Germany). Measurement of 50 COTS cubes at INFN (Mondaini et al., 2018), shows a loss of cross section of only 33% (Slide 10). Simulations show that systematic range errors on the order of a half millimeter are possible for a spherical geodetic satellite such as LARES. Adjustments for the holding and ejection system result in some loss of accuracy.

An Improved Pedestrian Ttracking Method Based on Wi-Fi Fingerprinting and Pedestrian Dead Reckoning

Wi-Fi based positioning has great potential for use in indoor environments because Wi-Fi signals are near-ubiquitous in many indoor environments. With a Reference Fingerprint Map (RFM), fingerprint matching can be adopted for positioning. Much assisting information can be adopted for increasing the accuracy of Wi-Fi based positioning. One of the most adopted pieces of assisting information is the Pedestrian Dead Reckoning (PDR) information derived from inertial measurements. This is widely adopted because the inertial measurements can be acquired through a Commercial Off The Shelf (COTS) smartphone. To integrate the information of Wi-Fi fingerprinting and PDR information, many methods have adopted filters, such as Kalman filters and particle filters. A new methodology for integration of Wi-Fi fingerprinting and PDR is proposed using graph optimization in this paper. For the Wi-Fi based fingerprinting part, our method adopts the state-of-art hierarchical structure and the Penalized Logarithmic Gaussian Distance (PLGD) metric. In the integration part, a simple extended Kalman filter (EKF) is first used for integration of Wi-Fi fingerprinting and PDR results. Then, the tracking results are adopted as initial values for the optimization block, where Wi-Fi fingerprinting and PDR results are adopted to form an concentrated cost function (CCF). The CCF can be minimized with the aim of finding the optimal poses of the user with better tracking results. With both real-scenario experiments and simulations, we show that the proposed method performs better than classical Kalman filter based and particle filter based methods with both less average and maximum positioning error. Additionally, the proposed method is more robust to outliers in both Wi-Fi based and PDR based results, which is commonly seen in practical situations.

Pushing the Data Rate of Practical VLC via Combinatorial Light Emission

Visible light communication (VLC) systems relying on commercial-off-the-shelf (COTS) devices have gathered momentum recently, due to the pervasive adoption of LED lighting and mobile devices. However, the achievable throughput by such practical systems is still several orders below those claimed by controlled experiments with specialized devices. In this paper, we engineer CoLight aiming to boost the data rate of the VLC system purely built upon COTS devices. CoLight adopts COTS LEDs as its transmitter, but it innovates in its simple yet delicate driver circuit wiring an array of LED chips in a combinatorial manner. Consequently, modulated signals can directly drive the on-off procedures of individual chip groups, so that the spatially synthesized light emissions exhibit a varying luminance following exactly the modulation symbols. To obtain a readily usable receiver, CoLight interfaces a COTS PD with a smartphone through the audio jack, and it also has an alternative MCU-driven circuit to emulate a future integration into the phone. The evaluations on CoLight are both promising and informative: they demonstrate a throughput up to 80 kbps at a distance of 2 m, while suggesting various potentials to further enhance the performance.

Toward a Fault-Tolerant Star Tracker for Small Satellite Applications

Star trackers are autonomous, high-accuracy electronic systems used to determine the attitude of a spacecraft. In recent years, commercial-off-the-shelf (COTS)-based star trackers are growing in importance for low-cost and short-duration missions, but their fault tolerance against soft errors has not been studied in detail. In this paper, we propose a self-healing system protected with ad hoc techniques that can be used as the first step to implement a fault-tolerant COTS-based star tracker for smallsat applications.

Characterization of a COTS-Based RF Receiver for Cubesat Applications.

This paper reports the experimental results of a test campaign performed on the radio-frequency (RF) receiver prototype operating at a 2025–2110 MHz frequency range, designed and fabricated for CubeSat applications. The prototype has been tested through a board-level test approach for the verification of the functional requirements and a component-level one for specific characterization measures. The tests have shown the following results: a −115–−70 dBm sensitivity range, 390 MHz intermediate frequency, a 0 dBm output power level with ±1 dB error, a 2.34 dB noise figure, and a 4.86 W power absorption. Such results have been largely achieved implementing an automatic gain control system by cascading two Commercial Off-The-Shelf (COTS) amplifiers. Moreover, an innovative technique based on RF test points has been successfully experimented and validated to measure the S-parameters of a custom low-pass filter integrated on the receiver, showing the possibility of even characterizing the single COTS components exposed to radiation through a unique board-level test setup. The technique may have a great impact on the cost reduction of electronic boards for space applications, since it would avoid using expensive evaluation boards for each COTS component that needs a radiation test.