Fail-safe Mode Research Articles

Reduction Jammer Detection and Recovery Algorithms for DSRC Safety Application in VANET

Intelligent Transportation Systems (ITS) encompasses technologies, services, and applications facilitating communication between vehicles (V2V) and between vehicles and fixed infrastructure (V2I and I2V). This mutual interaction constitutes a Vehicular Ad-Hoc Network (VANET) which supports a plethora of applications targeting critical transportation aspects, such as safety, mobility, and environmental considerations. Dedicated Short Range Communications (DSRC), operating on the 5.9 GHz band, is pivotal for such exchanges. We introduced an innovative algorithm designed to identify jamming attacks and transition the Safety Application to a secure fail-safe mode. This algorithm leverages a dual-metric strategy, incorporating both distance and PDR measurements. Field tests confirm that our algorithm adeptly recognizes the activities of deceptive jammers, ensuring a prompt shift of the safety application into its fail-safe state. This paper delves into these countermeasures, evaluating their efficiency via mathematical modeling, simulations, and on-ground testing. Findings acknowledge that these strategies bolster the reliability of safety applications in jamming scenarios. Furthermore, the approaches propounded align with ongoing standardization endeavors by relevant authorities, ensuring communication mediums remain unhindered.

Intent-Based Security for Functional Safety in Cyber-Physical Systems

We propose a novel intent-based method to prevent security attacks on the safety functions in cyber-physical systems used in smart manufacturing. Context information about a cyber-physical system is collected from various sensors including non-safety sensors measuring device temperature, motor rotation speed, or instantaneous power consumption of machines. Such contextual information along with operational and business intent of the system under consideration are then used to check whether the current situation is indeed an emergency situation or a normal situation. Unlike the conventional safety systems that only rely on raw sensor data and safety protocol status packets from safety sensors, which might be spoofed and/or modified, decision on the safety situation in our method is intelligently made by comparing aggregated sensor information from the cyber-physical system and its environment for compliance with pre-configured operational intents that define the normal safe and secure operation of the system. We also show how to integrate Machine Learning (ML) and Artificial Intelligence (AI) into the proposed method for efficient and automated analysis of both intents and aggregated context information to make more intelligent decisions in execution of functional safety protocols. Our proposed AI/ML integration approach also enables the prediction of safety critical situations before they occur. The proposed method aims to prevent unnecessary switching to fail-safe mode causing insecure system states such as emergency doors opening or system halting in normal situations. In addition, it prevents sticking in non-safe states and not switching to fail-safe mode in real emergencies which could cause hazard on device and/or people.

A Fan-Controlled Sodium-to-Air Heat Exchanger Configuration for Failsafe Decay Heat Removal in Sodium-Cooled Fast Reactors

Passive safety systems help to improve overall plant safety, reliability, and resilience. However, the real gain in the use of passive systems depends on the robustness of the design utilizing the passive process and the role of active elements, if any. In this paper, we propose a fan-controlled sodium-to-air heat exchanger (AHX) system design for a failsafe and passive decay heat removal (DHR) function in a pool-type sodium-cooled fast reactor. The proposed system uses a fan to control air flow and minimize heat loss during normal operation, and when the fan trips due to loss of power or a trip signal, DHR gets enabled in a failsafe mode. The system is analyzed with the help of a simplified one-dimensional model as well as with detailed computational fluid dynamics software. It is found from analysis that it is possible to control and maintain the air flow to about 4% to 5% of full flow, as in the case of conventional dampers, to minimize heat loss during normal reactor operation. The reliability of the proposed system is also analyzed and shows that the fan-controlled AHX-based decay heat removal system (DHRS) has a much better reliability compared to the conventional passive DHRS with active damper-dependent operation.

Exploration into the Needs and Requirements of the Remote Driver When Teleoperating the 5G-Enabled Level 4 Automated Vehicle in the Real World-A Case Study of 5G Connected and Automated Logistics.

Connected and automated vehicles have the potential to deliver significant environmental, safety, economic and social benefits. The key advancement for automated vehicles with higher levels of automation (SAE Level 4 and over) is fail-operational. One possible solution for the failsafe mode of automated vehicles is a 5G-enabled teleoperation system controlled by remote drivers. However, knowledge is missing regarding understanding of the human-machine interaction in teleoperation from the perspective of remote drivers. To address this research gap, this study qualitatively investigated the acceptance, attitudes, needs and requirements of remote drivers when teleoperating a 5G-enabled Level 4 automated vehicle (5G L4 AV) in the real world. The results showed that remote drivers are positive towards the 5G L4 AV. They would like to constantly monitor the driving when they are not controlling the vehicle remotely. Improving their field of vision for driving and enhancing the perception of physical motion feedback are the two key supports required by remote drivers in 5G L4 AVs. The knowledge gained in this study provides new insights into facilitating the design and development of safe, effective and user-friendly teleoperation systems in vehicle automation.

FIRE: A Finely Integrated Risk Evaluation Methodology for Life-Critical Embedded Systems

Life-critical embedded systems, including medical devices, are becoming increasingly interconnected and interoperable, providing great efficiency to the healthcare ecosystem. These systems incorporate complex software that plays a significantly integrative and critical role. However, this complexity substantially increases the potential for cybersecurity threats, which directly impact patients’ safety and privacy. With software continuing to play a fundamental role in life-critical embedded systems, maintaining its trustworthiness by incorporating fail-safe modes via a multimodal design is essential. Comprehensive and proactive evaluation and management of cybersecurity risks are essential from the very design to deployment and long-term management. In this paper, we present FIRE, a finely integrated risk evaluation methodology for life-critical embedded systems. Security risks are carefully evaluated in a bottom-up approach from operations-to-system modes by adopting and expanding well-established vulnerability scoring schemes for life-critical systems, considering the impact to patient health and data sensitivity. FIRE combines a static risk evaluation with runtime dynamic risk evaluation to establish comprehensive risk management throughout the lifecycle of the life-critical embedded system. We demonstrate the details and effectiveness of our methodology in systematically evaluating risks and conditions for risk mitigation with a smart connected insulin pump case study. Under normal conditions and eight different malware threats, the experimental results demonstrate effective threat mitigation by mode switching with a 0% false-positive mode switching rate.

Investigation of Modified Auxetic Structures from Rigid Rotating Squares.

Auxetic structures exhibit unusual changes in size, expanding laterally upon stretching instead of contracting. This paper presents this effect in a failsafe mode in structures made of rigid squares. We applied the concept of auxetic structures made of rigid rotating squares (from Grima and Evans) and offer a novel solution for connecting them. By introducing axes of rotation on the surface of the squares, a reliable working system is obtained, free from stress, in which the squares can come into contact with each other and completely cover the surface of the structure, or, in the open position, form regularly arranged pores. Herein, we present a new 2D auxetic metamaterial that is mathematically generated based on a theoretical relationship of the angle between the edges of a square and the position of the axis of rotation. Physical models were generated in the form of a planar structure and in the form of a circular closed structure. Such physical models confirmed our initial considerations and the geometrical relationships, offering new application possibilities. The novel structure that was designed and manufactured for the purpose of the paper can be considered as a new proposal in the market of auxetic materials.

Scalable constrained attributes/issues about risk, reliability and optimization in large scale battery pack

This study focuses on the optimization of scalable battery pack designs, as a scalable battery pack design can tolerate cell failures, implement a fail-safe mode, rapidly reconfigure itself, and adequately supply the load without interruptions. Hot-swapping, bypass mechanisms, configurability, and redundancy are the key attributes of scalable architecture, which enable the batteries to perform the aforementioned tasks. Scalable designs proposed in the literature still have many limitations, such as suboptimal utilization of the battery packs, low practicality, risk of internal short-circuiting of the batteries, increased weight and size of the battery packs, reliability issues under variable loads, and undesired delays in the reconfiguration of switches. The attributes and issues identified above form the basis of this study. First, the concept of practicality is highlighted for realization of scalable designs in real applications. Scalability associated issues, such as switching risk and sub-optimal sizing are explored. The tree algorithm is applied to develop a scalable design with higher power reliability and faster power redistribution. An SOH balancing method is proposed to optimize the utilization of battery pack. Sample of scalable designs and a physics-based electrochemical battery model are used to implement the proposed algorithms. The results confirm that the proposed SOH balancing can prolong the battery life. Additionally, the tree algorithm based design improves the power reliability, and enables fast redistribution of power.

ПРОЕКТУВАННЯ БПЛА САМОЛЬОТНОГО ТИПУ НА БАЗІ FIRMWARE ARDUPILOT

The paper considers the construction of a budget (no more than $ 150) aircraft-type UAV, which is able to perform the following flight modes: holding altitude and position, automatic return to the take-off point on command from the control panel or loss of communication with it, automatic flight along a given trajectory. During flight tests, the high aerodynamic qualities of the C-1 CHASER flying wing model were noted compared to models that were made from foam on their own. So, the flight time increased by ~ 25%, the speed by ~ 30% with the same flight weight and power consumption from the battery. It was experimentally established that it is possible to fly along the points of a designed aircraft with an APM 2.6 flight controller and Arduplane firmware with the obligatory use of a barometer and a magnetometer, in the same way as for a rotor-type UAV for performing similar tasks. The possibility was established using the Mission Planner ground station and the Google Earth Pro service to construct a real flight path of an aircraft using log files generated by the flight controller. The correspondence between the real flight trajectory of the aircraft and the trajectory entered into the flight controller using a ground station was experimentally determined. During flight tests, the correct operation of the failsafe mode was shown in the event of a loss of communication with the control equipment. The maximum operating range of the FlySky FS-i6 control equipment with the FS-IA6B receiver was set, which was 1.3 km in the absence of interference in the field. It was found that when the failsafe mode is disabled, the wing can fly to a distance from the take-off point, limited only by the battery charge (about 40 minutes at a speed of 40-45 km / h). When analyzing real flight trajectories, it was found that the firmware of the Arduplane, when flying along the trajectory, provides a more accurate passage of flight points, and the sections of passage between the points are straightforward, in contrast to the flight with the INAV firmware. We also noticed a smoother behavior of the wing when making turns, in contrast to the INAV.

Multi-level swell voltage control for minimizing the damage to an on-grid system

This article presented multi-level swell voltage control for minimizing the damage to an on-grid system between 1.3 to 1.8 pu. in compliance with the value regulated by IEEE and IEC standards. A window comparator circuit and comparator circuit with hysteresis transistor were used as the voltage detector and the excessive pulse entering the multi-level control of the load. According to the designed function in every stage in the form of fail-safe AND gate, the system was set for this case by turning to the fail-safe mode in order to prevent a fail-dangerous mode that might harm the electric system if the device in the detection circuit is deprived of qualification which is against the condition. Due to the Failure Mode and Effect Analysis (FMEA) in accordance with IEC-6196-1, the function prevents the electric and electronic devices of the on-grid system from damage. The design and installation of the electric protection device SVSS has a parallel-connect with the electric system without the concern of the load’s current.

Multi-level swell voltage control for minimizing the damage to an on-grid system

This article presented multi-level swell voltage control for minimizing the damage to an on-grid system between 1.3 to 1.8 pu. in compliance with the value regulated by IEEE and IEC standards. A window comparator circuit and comparator circuit with hysteresis transistor were used as the voltage detector and the excessive pulse entering the multi-level control of the load. According to the designed function in every stage in the form of fail-safe AND gate, the system was set for this case by turning to the fail-safe mode in order to prevent a fail-dangerous mode that might harm the electric system if the device in the detection circuit is deprived of qualification which is against the condition. Due to the Failure Mode and Effect Analysis (FMEA) in accordance with IEC-6196-1, the function prevents the electric and electronic devices of the on-grid system from damage. The design and installation of the electric protection device SVSS has a parallel-connect with the electric system without the concern of the load’s current.

Developing a fail-safe culture in a cyber environment using MySQL replication technique

Purpose The dependence on the use of information systems for nearly every activity and functions in the internet is increasingly high. This form of interconnectedness has bolstered national economies, enhanced how governments interact with their citizens and how ordinary people connect with friends and family. However, this dependence has equally resulted to a high rise in vulnerability, threat and risk associated with more use of information and communication technology. Cyber-attacks that have the potential to disrupt or damage information system infrastructure are getting more complex with some level of sophistication. Traditional protection of information system infrastructure is no longer sufficient; systems have proven to be immune to failure or incidents. This paper aims to ensure that there is a continuous availability of services through a fail-safe proof. Design/methodology/approach MYSQL replication technique was used to develop a model based on three-tier layers using the principle of network interdependency and the replication techniques. Tier 1 depicts a Telecom organization serving as service provider that provides internet service to Tier 2 organization – a Bank; Tier 3 is the financial App that can be used by bank staff and customers. The fail-safe mode integrated mechanism enables Tier 3 to continue to render its services in the event of an attack on Tier 1 such as DDoS without disruption. Findings This technique succeeded in mitigating the loss of data if cyber incident occurred or reception of uninterrupted services is countered, which give rise to future master-to-master architecture. Research limitations/implications The study conducted is limited to the design and development of a fail-safe system for interdependent networks or systems using MYSQL replication technique. Originality/value In an interdependent environment such as the cyberspace, the sectors are interdependent for optimal results. The originality of the work ensures that there is availability of services which is sustained and that data integrity is assured using the fail-safe technique based on MySQL replication method.

Tractor Beam

The consumer drone market is booming. Consumer drones are predominantly used for aerial photography; however, their use has been expanding because of their autopilot technology. Unfortunately, terrorists have also begun to use consumer drones for kamikaze bombing and reconnaissance. To protect against such threats, several companies have started “anti-drone” services that primarily focus on disrupting or incapacitating drone operations. However, the approaches employed are inadequate, because they make any drone that has intruded stop and remain over the protected area. We specify this issue by introducing the concept of safe-hijacking , which enables a hijacker to expel the intruding drone from the protected area remotely. As a safe-hijacking strategy, we investigated whether consumer drones in the autopilot mode can be hijacked via adaptive GPS spoofing. Specifically, as consumer drones activate GPS fail-safe and change their flight mode whenever a GPS error occurs, we performed black- and white-box analyses of GPS fail-safe flight mode and the following behavior after GPS signal recovery of existing consumer drones. Based on our analyses results, we developed a taxonomy of consumer drones according to these fail-safe mechanisms and designed safe-hijacking strategies for each drone type. Subsequently, we applied these strategies to four popular drones: DJI Phantom 3 Standard, DJI Phantom 4, Parrot Bebop 2, and 3DR Solo. The results of field experiments and software simulations verified the efficacy of our safe-hijacking strategies against these drones and demonstrated that the strategies can force them to move in any direction with high accuracy.

Multi-agent large-scale parallel crowd simulation with NVRAM-based distributed cache

This paper presents the architecture, main components and performance results for a parallel and modular agent-based environment aimed at crowd simulation. The environment allows to simulate thousands or more agents on maps of square kilometers or more, features a modular design and incorporates non-volatile RAM (NVRAM) with a fail-safe mode that can be activated to allow to continue computations from a recently analyzed state in case of a failure. We show results for an evacuation scenario for an area of up to 6 km2 in a district of Gdansk, Poland, performed on two clusters, one with hardware simulation of NVRAM. We have shown a very small overhead of using NVRAM compared to the RAM only solution and an overhead of 20% with the fail-safe mode on using NVRAM, shown up to 30 000 agents and up to 25 000 iterations of the simulation. We also show the benefit of using NVRAM for file synchronization with a slow growth of the execution time while increasing the map size. We then present how the frequency of visualization affects execution time and very good scaling of the proposed solution in a cluster environment for more than 650 processes and 60 000 agents.

Ensure an original and safe “fail-to-open” mode in planar and trench power SiC MOSFET devices in extreme short-circuit operation

The purpose of this paper is to present a complete experimentation of the two failure modes in competition that can appear during short-circuit (SC) fault operation of single-chip 1,2 kV SiC MOSFETs from different manufacturers including planar and trench-gate structures, well-known or recent devices. Ruggedness and selective failure modes are identified in relation with the power density dissipated by the chip and the simulated 1D-thermal junction. Finally, the chips of the devices which failed in a “fail-to-open” mode have been studied in order to find the physical reasons of this original and unusual fail-safe mode.

Three levels of fail-safe mode in MPI I/O NVRAM distributed cache

The paper presents architecture and design of three versions for fail-safe data storage in a distributed cache using NVRAM in cluster nodes. In the first one, cache consistency is assured through additional buffering write requests. The second one is based on additional write log managers running on different nodes. The third one benefits from synchronization with a Parallel File System (PFS) for saving data into a new file which allows to keep file history at the cost of space. We have shown that the three level fail-safe mode incorporating these versions does introduce minimal overhead for a random walk microbenchmark application for a 1GB file and checkpoints created every 2000 iterations, computing powers of a graph with 10000 vertices and up to 20% overhead for parallel processing of images up to 1000 megapixels compared to the basic NVRAM cache without fail-safe modes. We also presented times for checkpoint creation and restoring for sizes up to 10GBs.

Packaged peristaltic micropump for controlled drug delivery application.

Micropump technology has evolved significantly in the last two decades and is finding a variety of applications ranging from μTAS (micro Total Analysis System) to drug delivery. However, the application area of the micropump is limited owing to: simple pumping mechanism, ease of handling, controlled (microliter to milliliter) delivery, continuous delivery, and accuracy in flow rate. Here, the author presents the design, development, characterization, and precision flow controlling of a DC-motor driven peristaltic pump for controlled drug delivery application. All the micropump components were fabricated using the conventional fabrication technique. The volume flow variation of the pump has been characterized for different viscous fluids. The change in volume flow due to change in back pressure has been presented in detail. The fail-safe mode operation of the pump has been tested and leak rate was measured (∼0.14% leak for an inlet pressure of 140 kPa) for different inlet pressures. The precision volume flow of the pump has been achieved by measuring the pinch cam position and load current. The accuracy in the volume flow has been measured after 300 rotations. Finally, the complete system has been integrated with the necessary electronics and an android application has been developed for the self-administration of bolus and basal delivery of insulin.

Development of integrated electro-hydraulic braking system and its ABS application

This paper presented a new type of integrated EHB system. The EHB consisted of a compact three-chamber structure of master cylinder and mode switching valves. This allowed for the easy implementation of three different modes: normal mode, failsafe mode and ABS mode. In normal mode, a PWM control method was proposed for pressure regulation that took into account overshoot and hysteresis. To provide a favorable pedal feeling, a pedal stroke simulator was designed and integrated with the master cylinder. The failsafe and ABS modes were verified and the performance of the EHB in the three modes was evaluated using co-simulation and a bench test.

A Method for Online Diagnostics of Electromagnetic Relays Against Contact Welding for Safety Critical Applications

In a nuclear power plant, electromagnetic (EM) relays are often used to communicate TRIP signal configured in fail-safe mode. Online diagnostics is an important part of fault tolerant design. Relay contact welding is a failure mode of concern. Current methods do not allow for reliable online diagnostics of this failure mode without actually opening/closing the relays or without making measurements at contact side. In this paper, a technique for online diagnostics of EM relay without affecting the contact status is proposed. The method uses the differences in characteristic decay of coil current during deenergization process between a healthy and a relay whose contacts got welded. A test circuit is designed to verify the concept of deenergizing, followed by quick reenergization of relay coil. Diagnostic information is extracted, and the method is amenable for online automated execution. Results are satisfactory, and a welded contact is successfully detected and indicated by the circuitry. Reliability improvement achieved by deploying the proposed method is highlighted.

RPKI vs ROVER

BGP, the Internet's interdomain routing protocol, is highly vulnerable to routing failures that result from unintentional misconfigurations or deliberate attacks. To defend against these failures, recent years have seen the adoption of the Resource Public Key Infrastructure (RPKI), which currently authorizes 4% of the Internet's routes. The RPKI is a completely new security infrastructure (requiring new servers, caches, and the design of new protocols), a fact that has given rise to some controversy. Thus, an alternative proposal has emerged: Route Origin Verification (ROVER}, which leverages the existing reverse DNS (rDNS) and DNSSEC to secure the interdomain routing system. Both RPKI and ROVER rely on a hierarchy of authorities to provide trusted information about the routing system. Recently, however, it has been argued that the misconfigured, faulty or compromised RPKI authorities introduce new vulnerabilities in the routing system, which can take IP prefixes offline. Meanwhile, the designers of ROVER claim that it operates in a "fail-safe mode", where "[o]ne could completely unplug a router verification application at any time and Internet routing would continue to work just as it does today". There has been debate in Internet community mailing lists about the pros and cons of both approaches. This poster therefore compares the impact of ROVER failures to those of the RPKI, in a threat model that covers misconfigurations, faults or compromises of their trusted authorities.

Incomplete Rationality vs. Incomplete Strategy in Minority Game Model

Based on standard minority game, an Irrationality Agent Minority Game (IAMG) model is proposed, in which agents are less rational to make use of its strategy properly at each step. The control parameter of irrationality, pI, represents the probability of an agent acting irrationally, which could be explained with the personal defect. Like the incomplete (strategy) minority game (IMG) model introduced in our previous paper, this IAMG model also has three failsafe mode including (R0) random action, (R1) random strategy and (R4)”Back- to-Best”. The IAMG model can be explain with analytic equations similar with the IMG, and simulation results match the trend of the conclusion. Irrationality shows a great effect on system efficiency, and system efficiency reaches its top value at a smaller pIc than pIc in IMG. The IAMG and IMG model can be used to explain the deviation of some game theory simulations, and to understand the system performance with abundant agents of various characters.