Software Failure Modes Research Articles

Experimental Study on Fatigue Performance of Composite Box Girder With Steel Bottom Plate and Corrugated Steel Webs

In order to study the fatigue performance and fatigue failure mode of the composite box girder with steel bottom plate and corrugated webs (SBCSWs), the model beam was made and the constant and variable amplitude fatigue experiment were performed. Combined with ABAQUS finite element software, the strain, deflection, and fatigue failure mode of the composite box girder with SBCSWs were analyzed. The results showed that the slope of the load–deflection curve, the slope of the load–strain curve, and the neutral axis height of the model beam did not change during the constant amplitude fatigue test. In the variable amplitude fatigue test, as the fatigue loading time and fatigue load amplitude increased, the slope of the load–deflection curve and the slope of the load–strain curve of the model beam decreased significantly, while the neutral axis height increased significantly. The section strain of the composite box girder with SBCSWs was consistent with the quasi‐plane section assumption. The fatigue failure of the composite box girder with SBCSWs began at the stress concentration at the junction of the steel bottom plate and the corrugated webs. The fatigue fracture section has typical fatigue fracture characteristics.

Integrating Software FMEA and STPA to Develop a Bayesian Network-Based Software Risk Model for Autonomous Ships

The autonomous shipping industry is increasingly focusing on enhancing the safety and reliability of software-based systems. Conducting a risk assessment is a requirement for demonstrating the safety equivalence of autonomous ships based on such systems to conventional vessels. Traditional risk assessment models, however, primarily focus on hardware failures, often overlooking potential software-related failures and functional inadequacies. This study proposes a framework integrating Software Failure Mode and Effects Analysis (FMEA), System–Theoretic Process Analysis (STPA), and Bayesian Network (BN) for risk identification of autonomous ship software systems. The results of a case study reveal that the framework sufficiently addresses the multifaceted nature of risks related to software in autonomous ships. Based on the findings of this study, we suggest the need for standardization of software architecture development in the autonomous ship industry and highlight the necessity for an enhanced understanding of AI-specific risks and the development of tailored risk assessment methodologies.

Incorporating software failure in risk analysis––Part 2: Risk modeling process and case study

The advent of autonomous cars, drones, and ships, the complexity of these systems is increasing, challenging risk analysis and risk mitigation, since the incorporation of software failures intro traditional risk analysis currently is difficult. Current methods that attempt software risk analysis, consider the interaction with hardware and software only superficially. These methods are often inconsistent regarding the level of analysis and cover often only selected software failures. This paper is a follow-up article of Thieme et al. [1] and presents a process for the analysis of functional software failures, their propagation, and incorporation of the results in traditional risk analysis methods, such as fault trees, and event trees. A functional view on software is taken, that allows for integration of software failure modes into risk analysis of the events and effects, and a common foundation for communication between risk analysts and domain experts. The proposed process can be applied during system development and operation in order to analyses the risk level and identify measures for system improvement. A case study focusing on a decision support system for an autonomous remotely operated vehicle working on a subsea oil and gas production system demonstrates the applicability of the proposed process.

Incorporating software failure in risk analysis – Part 1: Software functional failure mode classification

Advanced technological systems consist of a combination of hardware and software, and they are often operated or supervised by a human operator. Failures in software-intensive systems may be difficult to identify, analyze, and mitigate, owing to system complexity, system interactions, and cascading effects. Risk analysis of such systems is necessary to ensure safe operation.The traditional approach to risk analysis focuses on hardware failures and, to some extent, on human and organizational factors. Software failures are often overlooked, or it is assumed that the system's software does not fail. Research and industry efforts are directed toward software reliability and safety. However, the effect of software failures on the level of risk of advanced technological systems has so far received little attention. Most analytical methods focus on selected software failures and tend to be inconsistent with respect to the level of analysis.There is a need for risk analysis methods that are able to sufficiently take hardware, software, and human and organizational risk factors into account. Hence, this article presents a foundation that enables software failure to be included in the general framework of risk analysis. This article is the first of two articles addressing the challenges of analyzing software failures and including their potential risk contribution to a system or operation. Hence, the focus is on risks resulting from software failures, and not on software reliability, because risk and reliability are two different aspects of a system.Using a functional perspective on software, this article distinguishes between failure mode, failure cause, and failure effects. Accordingly, 29 failure modes are identified to form a taxonomy and are demonstrated in a case study. The taxonomy assists in identifying software failure modes, which provide input to the risk analysis of software-intensive systems, presented in a subsequent article (Part 2 of 1) (Thieme et al.).

Research on Key Test Methods of the Smart Meter Software Based on Failure Modes

Software quality has become a key factor affecting the overall quality of the smart meter. To improve the reliability of the smart meter software, analyzed the typical failure modes and mechanism based on actual failure cases of smart meters. For different software failure modes, the test techniques were studied from the perspective of the software development cycle. Designed a test program of the smart meter software and provided automated test tools to improve the breadth and depth of the software test and improve the product reliability.

Research on Software Failure Modes and Key Testing Methods of the Smart Meter

Software quality has become a key factor affecting the overall quality of the smart meter. To improve the reliability of the smart meter software, this paper studies the software failure modes and influence analysis of the smart meter based on SFMEA, analyzes software failure modes and mechanisms, and establishes fault-knowledge base; the key technologies of static testing, dynamic testing, black-box testing and white-box testing were carried out for different software failure modes. The test programs of the life cycle of the smart meter software and the support of the automated testing tools are designed to improve the breadth and depth of the software testing, improve the reliability, reduce the operational failure and improve the service level of the electricity.

A Practical Analytical Approach to Increase Confidence in Software Safety Arguments

Complex interdependencies among a large and growing number of elements in computer-based critical systems have made the safety analysis process more burdensome in terms of costs and tend to limit the capabilities of current safety analysis approaches to address system hazards. Therefore, the critical systems lifecycle—primarily software-intensive systems—demands new approaches for conducting the safety analysis process while staying within reasonable cost limits and maintaining the quality of the results. This paper proposes a practical analytical approach for increasing the confidence in software safety arguments in safety cases through the elaboration and assessment of counterevidence that emerges from software failure modes due to robustness issues. A case study is presented in which the proposed approach is applied to a computer-based distributed critical system. Additionally, practical results from the application of this approach to real safety-critical systems are also presented. The proposed approach proved to be useful during safety analysis processes, mainly in independent safety analysis projects, as it improves assessment coverage with low impact on workload and costs.

SFTA-Based Approach for Safety/Reliability Analysis of Operational Use-Cases in Cyber-Physical Systems

The software is often responsible for controlling the behavior of mechanical and electrical components, as well as interactions among these components in cyber-physical systems (CPS). The risks in CPS systems could result in losing tools, features, performance and even life. Therefore, safety analysis for software in these systems is a highly critical and serious issue. In general, safety and reliability approaches play a major role in a risk management process in CPS. In this paper, after reviewing the major techniques of software reliability and safety in CPS, an software fault tree analysis (SFTA)-based approach is presented for analysis of operational use-cases (UC) in a CPS system. In our approach, the events related to use-cases are extracted, and the related SFTA is then obtained using the proposed algorithm. Moreover, a semi-automatic method is presented in this paper to produce software failure mode and effects analysis (SFMEA) from SFTA. The results of our approach are applicable for software safety analysis in a real CPS system, including the control system of Iranian National Observatory telescope. Assessment of the suggested method is performed through numerous safety/reliability criteria and the qualitative/quantitative analysis based on these criteria.

SFMEA assistant design method for control system using requirement modeling

Software Failure Modes and Effects Analysis (SFMEA) is an effective reliability analysis technique which is widely used in control systems. However, it is difficult to analyze the failure mode using traditional SFMEA method, as control system becomes more complicated. This paper proposed an assistant design method of SFMEA based on system requirement model, which would remedy the deficiencies in analyzing complex control system. An experiment shows that this method can be applicable to SFMEA for complex control system.

Failure mode taxonomy for assessing the reliability of Field Programmable Gate Array based Instrumentation and Control systems

Field Programmable Gate Arrays (FPGAs) are a form of programmable digital hardware configured to perform digital logic functions. This configuration (programming) is performed using Hardware Description Language (HDL), making FPGAs a form of HDL Programmed Device (HPD). In the nuclear field, FPGAs have seen use in upgrades and replacements of obsolete Instrumentation and Control (I&C) systems. This paper expands upon previous work that resulted in extensive FPGA failure mode data, to allow for the application of the OECD-NEA failure modes taxonomy. The OECD-NEA taxonomy presented a method to model digital (software-based) I&C systems, based on the hardware and software failure modes, failure uncovering effects and levels of abstraction, using a Reactor Trip System/Engineering Safety Feature Actuation System (RTS/ESFAS) as an example system. To create the FPGA taxonomy, this paper presents an additional “sub-component” level of abstraction, to demonstrate the effect of the FPGA failure modes and failure categories on an FPGA-based system. The proposed FPGA taxonomy is based on the FPGA failure modes, failure categories, failure effects and uncovering situations. The FPGA taxonomy is applied to the RTS/ESFAS test system, to demonstrate the effects of the anticipated FPGA failure modes on a digital I&C system, and to provide a modelling example for this proposed taxonomy.

Analysis of software safety and reliability methods in cyber physical systems

The software-based systems, alone do not cause any risk; but the risk is posed when the software-based systems are considered in the context of general systems where potential risks or hazards exist. Cyber-physical systems are cited as instances of software-based systems. Nowadays, safety and reliability of cyber-physical systems are considerably important due to the increasing complexity of these systems. Risk management techniques are required to reduce the risk to an acceptable level. Generally, safety and reliability methods are important in a risk management process among them software fault tree analysis (SFTA) and software failure modes and effects analysis (SFMEA) methods can be utilised. The main purpose of this article is to provide a comprehensive survey and evaluation of the currently available approaches for software safety and reliability methods in cyber-physical systems in order to reflect the state of the art of this active area.

Software Safety Analysis of Ball Position Control System using SFMEA

Software Failure Modes and Effects Analysis (SFMEA) is a traditional system safety analysis technique which is widely used in the aerospace, automotive and other safety-critical intensive systems. However, traditional FMEA methods are difficult to identify and analyzing the failure modes which caused by the dynamic logical information between interfaces or functions, such as softwarehardware interaction. To intuitively assume the effects of module failures in a system, numerous approaches have been proposed. This work addresses the use of SFMEA by using an experiment for safety-critical embedded control systems. The work presented here provides a general example illustrating how SFMEA can be effectively applied to an 8-bit micro-controller (Chip 89S52) based computer control system having little or no hardware protection. This paper also describes Functional FMEA, interface FMEA, and detailed software FMEAs. The experimental results of SFMEA also found the hardware failures and memory faults. The safety analysis reveals several design deficiencies and physical faults for which modifications are needed. This paper also found that, when properly implemented SFMEA at the right point in the Software Development Life cycle, it makes requirements, design and code reviews more effective. It also identifies single point failures due to software.

The applications of SFTA and SFMEA approaches during software development process: an analytical review

Software fault tree analysis SFTA and software failure modes and effects analysis SFMEA are two well known recommended approaches for the analysis of software induced hazards in the system and are adapted in the software domain by employing the concepts of standard hardware safety approaches namely fault tree analysis FTA and failure modes and effects analysis FMEA respectively. Both SFTA and SFMEA approaches, since their inception in the software domain, have been explored, either individually or jointly, by researchers at different stages of software development. This paper presents the critical review of the published work about the applications of both these approaches in three phases, namely requirements analysis, design and implementation/coding phases of software life cycle. After presenting the analytical review, the paper identifies the problems that are currently faced during the applications of these approaches and guides the directions for carrying out further research.

A SFMEA Method Based on Modeling and Simulation by Rhapsody

Software Failure Modes and Effects Analysis (SFMEA) technology is the most common technique in reliability and safety analysis. The common software FMEA methods are summarized and for object-oriented software, combined with the Rhapsodys characteristic of modeling and simulation, we proposed the SFMEA method based on modeling and simulation by Rhapsody and gave the process of implementation, the acquisition methods of failure modes and the SFMEA example.

DEVELOPMENT AND APPLICATION OF SFMEA MODEL TO SOFTWARE TESTING ENVIRONMENT

In software industry, the concept of quality has become a significant aspect and is expressed and defined in many different ways. Quality assurance, and in particular software testing and verification, are areas that yet have much to offer to the industry. This paper emphasizes the importance of a quality process and also discusses about the ways in which it could be achieved through offline software quality techniques in particular SFMEA Model. Software FMEA determines the software failure modes that are likely to cause top level failure events. Software FMEAs are useful when designing and testing the error handling part of the software process. It has to be found that there is significant improvement in quality in terms of reduced RPN values. A detailed literature was collected for the SFMEA model. The application of these SFMEA model for the software development is very much limited. Only few papers were highlighted the application of these model in software industry. The objectives can be achieved by developing the SFMEA model for the software development of three banking projects. The construction of the SFMEA model was compiled for the software development. The causes and effects for the failures were analyzed and validated using the SFMEA model.

Risk analysis: a guiding force in the improvement of testing

The authors propose a state-based risk assessment methodology at the analysis and design stage of Software Development Life Cycle. First, a method is proposed to estimate the risk for various states of a component within a scenario and then, the risk for the whole scenario is estimated. The key data needed for risk assessment are complexity and severity. An Inter-Component State-Dependence Graph is introduced to estimate the complexity for a state of a component within a system. The severity for a component within a scenario is decided based on three hazard techniques: Functional Failure Analysis, Software Failure Mode and Effect Analysis and Software Fault Tree Analysis. The risk for a scenario is estimated based on the risk of interacting components in various states within the scenario and State COllaboration TEst Model of the scenario. Finally, the system risk is estimated based on two inputs: scenarios risks and Interaction Overview Diagram of the system. The methodology is applied on a Library Management System case study. An experimental comparative analysis is performed and observed that the testing team guided by our state-based risk assessment approach achieves high test efficiency compared with it with an existing component-based risk assessment approach.

Bi-directional fault analysis of evaporator inspection system

In this paper, we have performed a safety analysis on an automotive evaporator inspection system. We performed the bi-directional analysis on the manufacturing line. Software Fault Tree Analysis (SFTA) as backward analysis and Software Failure Modes, Effects, & Criticality Analysis (SFMECA) as forward analysis are performed alternately to detect potential cause-to-effect relations. The analysis results indicate the possibility of searching and summarizing fault patterns for future reusability.

Probabilistic risk assessment modeling of digital instrumentation and control systems using two dynamic methodologies

The Markov/cell-to-cell mapping technique (CCMT) and the dynamic flowgraph methodology (DFM) are two system logic modeling methodologies that have been proposed to address the dynamic characteristics of digital instrumentation and control (I&C) systems and provide risk-analytical capabilities that supplement those provided by traditional probabilistic risk assessment (PRA) techniques for nuclear power plants. Both methodologies utilize a discrete state, multi-valued logic representation of the digital I&C system. For probabilistic quantification purposes, both techniques require the estimation of the probabilities of basic system failure modes, including digital I&C software failure modes, that appear in the prime implicants identified as contributors to a given system event of interest. As in any other system modeling process, the accuracy and predictive value of the models produced by the two techniques, depend not only on the intrinsic features of the modeling paradigm, but also and to a considerable extent on information and knowledge available to the analyst, concerning the system behavior and operation rules under normal and off-nominal conditions, and the associated controlled/monitored process dynamics. The application of the two methodologies is illustrated using a digital feedwater control system (DFWCS) similar to that of an operating pressurized water reactor. This application was carried out to demonstrate how the use of either technique, or both, can facilitate the updating of an existing nuclear power plant PRA model following an upgrade of the instrumentation and control system from analog to digital. Because of scope limitations, the focus of the demonstration of the methodologies was intentionally limited to aspects of digital I&C system behavior for which probabilistic data was on hand or could be generated within the existing project bounds of time and resources. The data used in the probabilistic quantification portion of the process were gathered partially from fault injection experiments with the DFWCS, separately conducted under conservative assumptions, partially from operating experience, and partially from generic data bases. The purpose of the quantification portion of the process was, purely to demonstrate the PRA-updating use and application of the methodologies, without making any particular claim regarding the specific validity and predictive value of the data utilized to illustrate the quantitative risk calculations produced from the qualitative information analytically generated by the models. A comparison of the results obtained from the Markov/CCMT and DFM regarding the event sequences leading to DFWCS failure modes show qualitative and quantitative consistency for the risk scenarios and sequences under consideration. The study also shows that: (a) the risk significance of the timing of system component failures may depend on factors that include the actual variability of initiating conditions of a dynamic transient, even within the nominal control range and (b) the range of dynamic outcomes may also be dependent on the choice of the assumed basic system-component failure modes included in the models, regardless of whether some of these would or would not be considered to have direct safety implications according to the traditional safety/non-safety equipment classifications.

A CASE STUDY ON FMEA APPLICATIONS TO SYSTEM RELIABILITY STUDIES

Failure Mode and Effect Analysis (FMEA) has been used quite extensively in aerospace industry for several years to establish hardware criticality. Determination of software reliability is equally important. There are several methods for determining software reliability. One methods for performing software reliability is the software FMEA. This paper discusses the application of principles to FMEA. A typical Tank pressurant is considered as an illustrative example. The tank pressurant system consists of three sets of solenoid valves (each set consists of a pair of valves), three pressure transducers, a vent valve, a heat exchanger and helium cold pressure bottles. Each set of solenoid valves consist of two solenoid valves connected in series. For the system to function properly, certain conditions have to be met. These are discussed in detail later in this paper. Based on the information provided from NASA, it is concluded that FMEA has to be capable of determining the software failure modes, effects and criticality as well as the hardware failure modes effects and criticality which includes the pressure transducers, solenoid valves, vent valve, heat exchanger and helium cold pressure bottles. The paper will discuss both the hardware and software FMEA application in detail.

Safety of computer control systems: challenges and results in software development

This paper reviews some results in improving software safety in computer control systems. The discussion covers various aspects of the software development process, as opposed to the product features. Software diversity, off-the-shelf software, failure mode and effect analysis, rigorous and formal software development are discussed.