Commercial Off-the-shelf Research Articles

Bare-Metal Redundant Multi-Threading on Multicore SoCs Under Neutron Irradiation

A software technique is presented to protect commercial multi-core microprocessors against radiation-induced soft errors. Important time overheads associated with conventional software redundancy techniques limit the feasibility of advanced critical electronic systems. In our approach, redundant bare-metal threads are used, so that critical computation is distributed over the different micro-processor cores. In doing so, software redundancy can be applied to Commercial Off-The-Shelf (COTS) micro-processors without incurring high-performance penalties. The proposed technique was evaluated using a low-cost single board computer (Raspberry Pi 4) under neutron irradiation. The results showed that the Redundant Multi-Threading versions detected and recovered all the Silent Data Corruption (SDC) events, and only increased HANG sensitivity with respect to the unhardened original versions. In addition, higher Mean Work to Failure (MWTF) estimations are achieved with our bare-metal technique than with the state-of-the-art bare-metal software-based techniques that only implement temporal redundancy.

Calibration of the Deposited Energy in CMOS Imagers for Particle Detection on Nanosatellites

Commercial off-the-shelf (COTS) CMOS sensors are increasingly used in scientific applications on nanosatellites. Applying a software-based approach and in addition to their image acquisitions tasks, these CMOS sensors can be used to detect ionizing particles to improve the fault tolerance of imaging instruments on nanosatellites without the need for additional hardware. A challenge in using COTS components for this approach is that essential radiation test data and important parameters such as the thickness of the sensitive epitaxial layer are typically not available. With a simplified calibration approach, we determine the epitaxial layer thickness and calibrate the deposited energy sensitivity with minimal measurement time and steps and minor requirements on the test facility. A forward model for particle track length determination with an increased angle scattering of incident protons is used to handle stronger parameter uncertainties of the test setup. It is shown that the currently used CMOS sensor (HWK1910A) is a suitable candidate for a radiation monitor, based on the determined epitaxial layer thickness and the deposited energy calibration factor, in combination with the in-orbit mission data. This enables capabilities for more individual protection measures in case of unexpected radiation environments.

Design Of Vfr Route Kendari Control Zone For Airplanes Flying To The Bombana Area

Haluoleo Kendari Airport serves local flight traffic, domestic and overflying traffic that passes through Kendari's airspace. Based on the data collected, it is known that Visual Flight Rules (VFR) flights from Haluoleo Kendari Airport to the Bombana region or vice versa do not have a VFR Route so that planes flying VFR fly direct routes. The research method used was Research and Development. Data collection techniques used were interviews and documentation studies. Meanwhile, data processing techniques use data reduction, data presentation, and verification. The author designed the VFR Route using the Commercial Off The Shelf (COTS) Software method. The suggestion that the author can give is for Perum Lembaga Penyelenggara Pelayanan Navigasi Penerbangan (LPPNPI) Kendari Branch to initiate Perum LPPNPI Headquarters for the creation of a VFR Route in the Kendari Control Zone that connects Haluoleo Kendari Airport to the Bombana area, so that air traffic services at Perum LPPNPI Kendari Branch are more optimal.

Stratospheric Night Sky Imaging Payload for Space Situational Awareness (SSA).

Space situational awareness (SSA) refers to collecting, analyzing, and keeping track of detailed knowledge of resident space objects (RSOs) in the space environment. With the rapidly increasing number of objects in space, the need for SSA grows as well. Traditional methods rely heavily on imaging RSOs from large, narrow field-of-view (FOV), ground-based telescopes. This research outlines the technology demonstration payload, Resident Space Object Near-space Astrometric Research (RSONAR)-a star tracker-like, wide FOV camera combined with commercial off-the-shelf (COTS) hardware to image RSOs from the stratosphere, overcoming the disadvantages of ground-based observations. The hardware components and software algorithm are described and evaluated. The eligibility of the payload for SSA is proven by the image processing algorithms, which detect the RSOs in the images captured during flight and the survival of the COTS components in the near-space environment. The payload features a low-resolution, wide FOV camera coupled with a Field Programmable Gate Array (FPGA)-based platform that houses the altitude and time-based image capture algorithm. The newly developed payload in a 2U-CubeSat form factor was flown as a space-ready payload on the CSA/CNES stratospheric balloon research platform to carry out algorithm and functionality tests in August 2022.

VitroBench: Manipulating in-vehicle networks and COTS ECUs on your bench: A comprehensive test platform for automotive cybersecurity research

With the increasing connectivity employed in automotive systems, remote cyber attacks have now become a possibility and concrete threat. Prior works on automotive cyber security solutions have primarily focused evaluation either on real cars or via emulations of electronic control units (ECUs). Evaluation on real cars offers limited flexibility in manoeuvring the packets communicated through in-vehicle network (IVN). Meanwhile, emulations of ECUs rely on assumptions that may not correspond to the exact features in an IVN.In this paper, we present VitroBench, a comprehensive test platform involving commercial off-the-shelf (COTS) ECUs that allows arbitrary packet control over IVN. In contrast to existing automotive testbed, an appealing feature of VitroBench is that it allows replication of driving use cases and scenarios directly on the testbed involving COTS ECUs. This, in turn, allows us to design and evaluate concrete attacks that are directly related to a driving scenario. We present the design of VitroBench that allows us to sniff, inject packets to and isolate targeted ECU via bridging. The isolation of ECUs also offers fuzzing the respective ECUs. We evaluate the capability of VitroBench via launching concrete attacks and demonstrating the impact of such attacks. We discuss the careful design choices involved in VitroBench that inspire automotive cybersecurity research in future.

Easy Peasy: A New Handy Method for Pairing Multiple COTS IoT Devices

Context-based IoT device paring is a popular solution for devices that lack an interface. However, it takes a proximate distance or a long time for IoT devices to sense highly correlated context with enough entropy. In this work, we present a novel approach for fast and secure multiple commercial off-theshelf (COTS) devices pairing in IoT scenarios. Our approach is based on the key idea that devices co-located within a physicallysecure boundary can perceive qualified context under the help of human-in-the-loop (HITL). Specifically, we leverage receivedsignal- strength (RSS) trajectory data with manually-generated interferences in a certain period as the shared secret to achieve fast and secure device pairing. Moreover, the real-time RSS trajectory data can be utilized to generate random numbers in lieu of pre-shared key (PSK), which makes our scheme more resistant to background attacks. We theoretically prove the security of our pairing scheme and implement it in some real-world environments. Our experimental results demonstrate that our scheme can effectively defend against malicious devices by imposing a threshold on the similarity of RSS trajectory data. The experimental results also show that, compared with the traditional context-based pairing that takes up to 24 hours, the legitimate device in our scheme takes only 10 seconds to pass the similarity check on average, which is efficient and feasible

Exertional Heat Strain Detection: Application of the Human Performance Model Based Systems Engineering System Architecture (MBSE‐SA)

AbstractExertional Heat Illness is a significant health concern for the US military, with over 12,300 incidents having occurred during the last five years. In order to help implement preventative measures, wearable devices can be used to provide military leaders with real‐time physiological status monitoring of warfighters. While there are a large number of commercial‐off‐the‐shelf (COTS) wearable devices that could be used for this purpose, not every wearable device is suitable for every military use case. To expedite the process of recommending which wearable systems are suitable for a variety of military use cases, we utilized the Wearables Model Based Systems Engineering System Architecture (MBSE‐SA) developed in our previous work. In addition, we developed a cost‐benefit simulation within the MBSE‐SA to allow users to visualize the cost impact of a chosen system on heat‐related medical costs.

Wi-Senser: Contactless Head Movement Detection during Sleep Utilizing WiFi Signals

Detecting human head movement during sleep is important as it can help doctors to assess many physical or mental health problems, such as infantile eczema, calcium deficiency, insomnia, anxiety disorder, and even Parkinson’s disease, and provide useful clues for accurate diagnosis. To obtain the information of head movement during sleep, current solutions either use a camera or require the user to wear intrusive sensors to collect the image or motion data. However, the vision-based schemes rely on light conditions and raise privacy concerns. Many people, including the elderly and infants, may be reluctant to wear wearable devices during sleep. In this paper, we propose Wi-Senser, a nonintrusive and contactless smart monitoring system for detecting head movement during sleep. Wi-Senser directly reuses the existing WiFi infrastructure and exploits the fine-grained channel state information (CSI) of WiFi signals to capture the minute human head movement during sleep without attaching any sensors to the human body. Specifically, we constructed a filtering channel including a Hampel filter, wavelet filter, and mean filter to remove outliers and noises. We propose a new metric of carrier sensitivity to select an optimal subcarrier for recording the change in targeted body movement from 30 candidate subcarriers. Finally, we designed a peak-finding algorithm to capture the real peak set recording the change in human head movement. We designed and implemented Wi-Senser with just one commercial off-the-shelf (COTS) router and one laptop equipped with an Intel 5300 network interface card (NIC). We evaluated the performance of Wi-Senser with 10 volunteers (6 adults and 4 children). Extensive experiments demonstrate that Wi-Senser can achieve 97.95% accuracy for monitoring head movement during sleep. Wi-Senser provides a new solution for achieving noninvasive, continuous, and accurate detection of minute human movement without any additional cost.

Design and Validation of a Low-Cost Mobile EEG-Based Brain-Computer Interface.

Objective: We designed and validated a wireless, low-cost, easy-to-use, mobile, dry-electrode headset for scalp electroencephalography (EEG) recordings for closed-loop brain-computer (BCI) interface and internet-of-things (IoT) applications. Approach: The EEG-based BCI headset was designed from commercial off-the-shelf (COTS) components using a multi-pronged approach that balanced interoperability, cost, portability, usability, form factor, reliability, and closed-loop operation. Main Results: The adjustable headset was designed to accommodate 90% of the population. A patent-pending self-positioning dry electrode bracket allowed for vertical self-positioning while parting the user's hair to ensure contact of the electrode with the scalp. In the current prototype, five EEG electrodes were incorporated in the electrode bracket spanning the sensorimotor cortices bilaterally, and three skin sensors were included to measure eye movement and blinks. An inertial measurement unit (IMU) provides monitoring of head movements. The EEG amplifier operates with 24-bit resolution up to 500 Hz sampling frequency and can communicate with other devices using 802.11 b/g/n WiFi. It has high signal-to-noise ratio (SNR) and common-mode rejection ratio (CMRR) (121 dB and 110 dB, respectively) and low input noise. In closed-loop BCI mode, the system can operate at 40 Hz, including real-time adaptive noise cancellation and 512 MB of processor memory. It supports LabVIEW as a backend coding language and JavaScript (JS), Cascading Style Sheets (CSS), and HyperText Markup Language (HTML) as front-end coding languages and includes training and optimization of support vector machine (SVM) neural classifiers. Extensive bench testing supports the technical specifications and human-subject pilot testing of a closed-loop BCI application to support upper-limb rehabilitation and provides proof-of-concept validation for the device's use at both the clinic and at home. Significance: The usability, interoperability, portability, reliability, and programmability of the proposed wireless closed-loop BCI system provides a low-cost solution for BCI and neurorehabilitation research and IoT applications.

SecChecker: Inspecting the security implementation of 5G Commercial Off-The-Shelf (COTS) mobile devices

Although 5G security has been further improved with the evolution of the standard, it remains to be checked whether 5G cellular devices (i.e., User Equipment or UE) have correctly implemented the designed security features following the specification. In this work, we present SecChecker, a security inspection system, to examine the security implementation of 5G devices. Firstly, to determine which security items to check, we extract 11 general Security Requirements (SRs) for 5G UEs after a comprehensive study of the 3GPP standard. Then we design corresponding Inspection Cases (ICs) for testing the UE implementation of these SRs. We implemented a prototype of SecChecker based on open-source 5G projects and utilized it to inspect 7 Commercial Off-The-Shelf (COTS) devices using 5G baseband chips from the top five vendors. The results indicate that most of the required key security features in the specification are securely implemented by the tested 5G devices. However, we also found several UE security implementations that do not meet the extracted SRs or that are vulnerable to exploits, as well as some protocol mismatches. To show the implications on mobile users using the affected 5G devices, we implement two proof-of-concept attacks including the 5G redirection attack and the 5G user plane Man-in-the-Middle attack, to exploit the identified security flaws. Finally, the mitigations are discussed.

CROWBAR: Natively Fuzzing Trusted Applications Using ARM CoreSight

Trusted execution environments (TEE) are deployed on many platforms to provide both confidentiality and integrity, and their extensive use offers a secure environment for privacy-sensitive operations. Despite TEE prevalence in the smartphone and tablet market, vulnerability research into TEE security is relatively rare. This is, in part, due to the strong isolation guarantees provided by its implementation. In this paper, we propose a hardware assisted fuzzing framework, CROWBAR, that bypasses TEE isolation to natively evaluate trusted applications (TAs) on mobile devices by leveraging ARM CoreSight components. CROWBAR performs feedback-driven fuzzing on commercial, closed source TAs while running in a TEE protected environment. We implement CROWBAR on 2 prototype commercial-off-the-shelf (COTS) smartphones and one development board, finding 3 unique crashes in 5 closed source TAs that are previously unreported in the TrustZone fuzzing literature.

GREATCUBE+: conceptual design tool for CubeSat’s design

CubeSats are a type of spacecraft which have become popular since the early 2000. They are known for their quick development time and low cost, when comparing them to larger satellites. However, there is a significant drawback which has been recorded during these years of operations, namely an high failure rate which turns almost half of them into space debris. The reasons behind these malfunctions are often attributed to flawed spacecraft design choices or failures of commercial off-the-shelf (COTS) products. To improve the design of CubeSats, several software tools for performing the conceptual design have been proposed. These tools are often limited in their capabilities and are not suitable for all types of CubeSat missions. To address this issue, the University of Applied Sciences Wiener Neustadt (FHWN) in cooperation with Technische Universität Dresden is developing a software tool called GREATCUBE+. Its goal is to increase the success rate of CubeSats by providing a satellite model which is composed of commercial-off-the-shelf (COTS) products backed up by empirical heritage, analytical proof, and numerical analysis. One of the main features of this tool is the ability of dealing with different typologies of payloads. GREATCUBE+ has been validated with various successful CubeSat missions and it provides design solutions with an accuracy of above 90% when it comes to CubeSat weights and volumes. Using this software, CubeSat design teams can proceed from the conceptual development to the testing and assembly phases quicker, hoping to result in higher quality CubeSats and fewer failures.

3D printed control for commercial off-the-shelf (COTS) close-range photogrammetric reconstruction

The use of photogrammetry in archaeology and anthropology has become increasingly popular over the past decade. If the intended purpose of a three-dimensional (3D) model generated by commercial “off-the-shelf” (COTS) photographic equipment is geometric analysis or preservation by record, appropriate 3D control is recommended to improve orientation estimates and, in turn, the accuracy of the output 3D model. Further, independent measures of the quality of the photogrammetric model (in addition to the 3D model output itself) are recommended for robust validation. This paper evaluates the use of bespoke 3D printed designs (cradles) to add both control points to close-range 3D model and check points for validation. There were no statistically significant differences between the control and check points errors and intra-observer error was low and comparable to conventional manual measurement methods, thus providing an accessible method of adding 3D control to close-range photogrammetry.

Best practices on adopting open-source and commercial low-cost devices in small satellites missions

The NewSpace approach of utilizing CubeSats and smaller satellites for complex LEO missions that once were reserved only for bigger platform, paired with the requirement of enduring reliability and quality assurance on batches of tens of satellites, is paving the way for the use of commercial-off-the-shelf (COTS) components in micro-satellite missions. The recent global supply chain issues and extended lead times in the procurement of micro-controllers, memories and passive electronic components, caused by the pandemic and factories shutdowns, have resulted in a forced procurement diversification of several key elements, even in partially assembled products.GAUSS has been designing, manufacturing, and launching Small Satellites since early 2000.Its tenth satellite, UNISAT-7, was launched by a Soyuz-Fregat LV on March 22nd, 2021. Thanks to the vast experience gained on the application of commercial components in all the subsystems developed by the company, the typical overall costs for a complete platform are substantially lower compared to competitors, while retaining similar reliability.UNISAT-7, developed using lean-satellite methodologies, included more than 28 independent subsystems with their own telemetry, and most of them were developed in-house using ground COTS components; no space-grade products were employed, to save on overall mission costs. Some systems were devised from the start using open-source hardware, to expedite the prototyping process, while having the benefit of using readily available software, generally included with these platforms. Raspberry embedded devices were employed on the flight model for two remote sensing systems, to test how such systems, duly adapted to sustain space conditions, may perform and show reliability similar to commercial space systems worth thousand times the value.All systems have been activated and successfully verified for an entire year in LEO. They were hardened for vacuum, extreme temperatures, radiation, and launch stresses using common items found in general hardware stores.This work will delve into the open-source/COTS components used, the process employed to strengthen them, and the programmed flight firmware routines for maximizing embedded devices’ reliability in space.

A Coaxial Pulsed Plasma Thruster Model with Efficient Flyback Converter Approaches for Small Satellites

Pulsed plasma thrusters (PPT) have demonstrated enormous potential since the 1960s. One major shortcoming is their low thrust efficiency, typically <30%. Most of these losses are due to joule heating, while some can be attributed to poor efficiency of the power processing units (PPUs). We model PPTs to improve their efficiency, by exploring the use of power electronic topologies to enhance the power conversion efficiency from the DC source to the thruster head. Different control approaches are considered, starting off with the basic approach of a fixed frequency flyback converter. Then, the more advanced critical conduction mode (CrCM) flyback, as well as other optimized solutions using commercial off-the-shelf (COTS) components, are presented. Variations of these flyback converters are studied under different control regimes, such as zero voltage switching (ZVS), valley voltage switching (VVS), and hard switched, to enhance the performance and efficiency of the PPU. We compare the max voltage, charge time, and the overall power conversion efficiency for different operating regimes. Our analytical results show that a more dynamic control regime can result in fewer losses and enhanced performance, offering an improved power conversion efficiency for PPUs used with PPTs. An efficiency of 86% was achieved using the variable frequency approach. This work has narrowed the possible PPU options through analytical analysis and has therefore identified a strategic approach for future investigations. In addition, a new low-power coaxial micro-thruster model using equivalent circuit model elements is developed.This is referred to as the Carlow–Stuttgart model and has been validated against experimental data from vacuum chamber tests in Stuttgart’s Pulsed Plasma Laboratory. This work serves as a valuable precursor towards the implementation of highly optimized PPU designs for efficient PPT thrusters for the next PETRUS (pulsed electrothermal thruster for the University of Stuttgart) missions.

Verification and Validation of ITER Interlock System Fast Architecture According to IEC 61508 Standard

The ITER Interlock Control System (ICS) requires the application of the IEC 61508 standard for all mission-critical (known as investment protection) control functions. Such functions must detect the events of the integrated physical processes and distribute them to the actuators with hard real-time constraints on the order of milliseconds or even microseconds. Systems able to achieve these timing requirements are often bespoke FPGA-based solutions, which are a well-known challenge to IEC 61508 processes. However, to minimize the variety of components and simplify the procurement process for an international supplier base, ITER decided to standardize the use of Commercial Off-The-Shelf (COTS) devices. The COTS selected for the ICS was the FPGA-based CompactRIO NI 9159 chassis (and several adapter I/O modules), provided by National Instruments (NI). This COTS requires the use of a high-level language (LabVIEW-FPGA) and the associated integrated development tools to develop the FPGA functionality. Therefore, it is necessary to ensure the required assurance that a COTS device is of sufficient quality, fit for purpose, and can be properly integrated into an investment protection control loop with the necessary level of systematic capability during the development process. This paper describes in detail the method ITER uses to perform the verification and validation according to the IEC 61508 standard recommendations, for the logic configuration generated by LabVIEW-FPGA for these COTS, after the compilation of high-level language sources designed during the development.

Improving Self-Consistency in Underwater Mapping Through Laser-Based Loop Closure

Accurate, self-consistent bathymetric maps are needed to monitor changes in subsea environments and infrastructure. These maps are increasingly collected by underwater vehicles, and mapping requires an accurate vehicle navigation solution. Commercial off-the-shelf (COTS) navigation solutions for underwater vehicles often rely on external acoustic sensors for localization; however, survey-grade acoustic sensors are expensive to deploy and limit the range of the vehicle. Techniques from the field of simultaneous localization and mapping, particularly loop closures, can improve the quality of the navigation solution over dead reckoning, but are difficult to integrate into COTS navigation systems. This article presents a method to improve the self-consistency of bathymetric maps by smoothly integrating loop-closure measurements into the state estimate produced by a commercial subsea navigation system. Integration is done using a white-noise-on-acceleration motion prior, without access to raw sensor measurements or proprietary models. Improvements in map self-consistency are shown for both simulated and experimental datasets, including a 3-D scan of an underwater shipwreck in Wiarton, ON, Canada.

Single-Target Real-Time Passive WiFi Tracking

Device-free human tracking is an essential ingredient for ubiquitous wireless sensing. Recent passive WiFi tracking systems face the challenges of inaccurate separation of dynamic human components and time-consuming estimation of multi-dimensional signal parameters. In this work, we present a scheme named WiFi Doppler Frequency Shift (WiDFS), which can achieve single-target real-time passive tracking using channel state information (CSI) collected from commercial-off-the-shelf (COTS) WiFi devices. We consider the typical system setup including a transmitter with a single antenna and a receiver with three antennas; while our scheme can be readily extended to another setup. To remove the impact of transceiver asynchronization, we first apply CSI cross-correlation between each RX antenna pair. We then combine them to estimate a Doppler frequency shift (DFS) in a short-time window. After that, we leverage the DFS estimate to separate dynamic human components from CSI self-correlation terms of each antenna, thereby separately calculating angle-of-arrival (AoA) and human reflection distance for tracking. In addition, a hardware calibration algorithm is presented to refine the spacing between RX antennas and eliminate the hardware-related phase differences between them. A prototype demonstrates that WiDFS can achieve real-time tracking with a median position error of 72.32 cm in multipath-rich environments.

A COMMERCIAL-OFF-THE-SHELF FREQUENCY MODULATED CONTINUOUS WAVE RADAR FOR VITAL SIGN MONITORING

Objective: Radar systems are capable of retrieving remotely micro-movements with very high precision. Millimeter-wave radars are already used in several medical applications (e.g. sleep disorders, heart beat rate, patient monitoring) and have shown promising results towards a remote Doppler cardiogram or arterial pulse wave measurements techniques. In this work, we tested a 122 GHz commercial-off-the-shelf (COTS) Frequency Modulated Continuous Wave (FMCW) radar for vital (respiratory and cardiac) signals monitoring. This required the setting up of a very precise experimental bench and the investigation of a robust data processing procedure. Design and method: An experimental bench (see Figure 1-a) has been set up with a high precision Newport linear actuator: a small target can be then displaced with less than 3 μm accuracy. Such system can replicate the thorax displacements due to the respiratory and cardiac activity. Two different motions were simulated: a ‘large’ 8 mm displacement at 0.15 Hz (a.k.a. respiratory) and a ‘small’ 0.5 mm at 1 Hz (a.k.a. cardiac). Furthermore, a shaker system can be used to reproduce completely arbitrary movements, even from real acquired Electrocardiogram (ECG) data. In this case, however, a reference measurement system would be necessary to determine the accuracy. Results: A first measurement set was dedicated to evaluate the accuracy of the radar system: around 50 acquisitions for each type of displacements were carried out. The accuracy of the radar measurements results in the order of ∼10 μm (see Figure 2). A second measurement set tested the dynamic resolution: in this case, a 0.4 Hz sinusoidal signal and a 0.8 Hz pulsation mix were fed to the shaker system. The radar is capable of retrieving both signal signatures (see Figure 3), with errors due to the combination of sharp pulse rise and low radar sampling frequency Conclusions: We show that a COST radar is able to retrieve vital signs chest displacements with a good accuracy in both amplitude and dynamics, thus representing a valid option for a remotely continuous cardiovascular monitoring. Next objectives are In Vivo measurements with an in-house radar system and measurements of blood pulse waves.

Impact of Ignition Assistant on Combustion of Cetane 30 and 35 Jet-Fuel Blends in a Compression-Ignition Engine at Moderate Load and Speed

Abstract This study investigates the use of a commercial-off-the-shelf (COTS) ceramic glow-plug to assist ignition of jet fuel blends with cetane numbers of 30 and 35, below the minimum cetane number of 40 for #2 diesel. Experiments were carried out on a single-cylinder compression-ignition engine operating at 1200 RPM for single and dual-injection (pilot + main) timing sweeps. The COTS glow-plug, termed the ignition assistant, was operated at varying input power levels between 0 and 70 W (stock maximum power input is 30 W) at each SOI. Results demonstrate that the use of an ignition assistant at the higher input powers (50 and 70 W) enables operation over a wider range of SOI timings where more advanced times are limited by high pressure-rise rates and more retarded times are limited by rapidly increasing coefficient of variation of gross indicated mean effective pressure. Use of the ignition assistant enables stable combustion at later injection timings increasing the operable range of SOI timings. For the CN 30 fuel, at earlier injection timings, pressure traces, and heat release analysis demonstrated the advancement of start of combustion and combustion phasing with the ignition assistant on. At retarded injection timings where combustion would not otherwise occur completely for the CN 30 fuel, operating the ignition assistant at the higher powers enabled combustion phasing to be advanced and combustion to be stabilized at conditions where, with the ignition assistant off, misfire (flameout) would occur. Furthermore, the ignition assistant enabled combustion phasing to follow an approximately linear response with respect to SOI timing over a wider range of SOI times.