Systems-Theoretic Accident Model And Processes Research Articles

A Wearable Fall Detection System Based on Body Area Networks

Falls can have serious consequences for people, leading to restrictions in mobility or, in the worst case, to traumatic-based cases of death. To provide rapid assistance, a portable fall detection system has been developed that is capable of detecting fall situations and, if necessary, alerting emergency services without any user interaction. The prototype is designed to facilitate reliable fall detection and to classify several fall types and human activities. This solution represents a life-saving service for every person that will significantly improve assistance in the case of fall events, which are a part of daily life. Additionally, this approach facilitates independent system operation, since the system does not depend on sensor or network units located within a building structure. This article also introduces fall analysis. To guarantee functional safety, a hazard analysis method named system-theoretic accident model and processes (STAMP) is applied.

A CAST-based causal analysis of the catastrophic underground pipeline gas explosion in Taiwan

A deep and thorough analysis of typical accidents beyond immediate failures from a systematic perspective is necessary for safety decision-making in an area. The Systems-Theoretic Accident Model and Processes (STAMP) is one of the most widely used accident models based on systems and control theory, which derives a powerful accident analysis tool defined as Causal Analysis based on Systems Theory (CAST). This study adopts a CAST analysis of the catastrophic underground pipeline gas explosion in Taiwan, which is one of the largest petroleum catastrophes in Chinese history. The safety control structure to enforce the safety constraints required by the system hazards is developed and analyzed hierarchically. The analysis has systematically demonstrated the inadequate control and violated safety constraints and uncovered the in-depth rationale behind the decisions that were made leading up to this tragedy. The necessary changes in the overall system safety structure are also recommended based on control flaws identified for each hierarchical level, accordingly. The CAST model is demonstrated to be feasible for continuous improvements in accident analysis and in turn establishing a robust safety system of pipeline gas transportation in Taiwan.

An Accident Model with Considering Physical Processes for Indoor Environment Safety

Accident models provide a conceptual representation of accident causation. They have been applied to environments that have been exposed to poisonous or dangerous substances that are hazardous in nature. The home environment refers to the indoor space with respect to the physical processes the of indoor climate, e.g., temperature change, which are not hazardous in general. However, it can be hazardous when the physical process is in some states, e.g., a state of temperature that can cause heat stroke. If directly applying accident models in such a case, the physical processes are missing. To overcome this problem, this paper proposes an accident model by extending the state-of-the-art accident model, i.e., Systems-Theoretic Accident Model and Process (STAMP) with considering physical processes. Then, to identify causes of abnormal system behaviors that result in physical process anomalies, a hazard analysis technique called System-Theoretic Process Analysis (STPA) is tailored and applied to a smart home system for indoor temperature adjustment. The analytical results are documented by a proposed landscape genealogical layout documentation. A comparison with results by applying the original STPA was made, which demonstrates the effectiveness of the tailored STPA to apply in identifying causes in our case.

Hazard Analysis for Escalator Emergency Braking System via System Safety Analysis Method Based on STAMP

Due to the complex mechanical structure and control process of escalator emergency braking systems (EEBS), traditional hazard analysis based on the event chain model have limitations in exploring component interaction failure in such a complex social-technical system. Therefore, a hazard analysis framework is proposed in this paper for hazard analysis of complex electromechanical systems based on system-theoretic accident model and process (STAMP). Firstly, basic principles of STAMP are introduced and comparison with other hazard analysis methods is conducted, then the safety analysis framework is proposed. Secondly, a study case is performed to identify unsafe control actions of EEBS from control structures, and a specific control diagram is organized to recognize potential example casual scenarios. Next, comparison between fault tree analysis and STAMP for escalator’s overturned accident shows that hazards related to component damaged can be identified by both, while hazards that focus on components interaction can only be identified by STAMP. Besides, single control way and tandem operation process are found to be the obvious causal factors of accidents. Finally, some improvement measures like decibel detection or vibration monitoring of key components are suggested to help the current broken chain detection to trigger the anti-reversal device for a better safe EEBS.

An initial evaluation framework for the design and operational use of maritime STAMP-based safety management systems

A safety management system (SMS) is the common means used by organizations to assess organizational performance with respect to the safety and well-being of people, property and the natural ecosystem. A SMS provides confidence to diverse stakeholders that organizational safety is at an appropriate level and fulfils the applicable regulatory standards. As a multifaceted system for organizational safety assessment, ensurance and assurance, the evaluation of the design and operational use of SMS is a complex process. An evaluation needs to provide evidence about how well the design and operation of an SMS complies with applicable standards and how well the methods used in the SMS implementation support the organizational policies and practical work. In the maritime domain, SMS is broadly applied. However, there are few theoretically rooted SMS design approaches, and there is a lack of frameworks to evaluate how well the SMS is designed and how effectively it operates. This paper proposes an initial evaluation framework for the design and operational use of a maritime SMS design approach based on Systems-Theoretic Accident Model and Processes (STAMP), realist evaluation and Bayesian Networks. This framework is applied for a case study of vessel traffic services (VTS) Finland to test its relevance and ability to guide the SMS design. The experiences gained in the case study, and the related discussion on the framework, can guide further research in this area. Ultimately, the work can be used as a basis for developing maritime SMS auditing processes, based on specific theoretical and methodological approaches.

Meeting Report

The Amsterdam University of Applied Sciences organised in Amsterdam (31 October - 2 November 2018) the 6th edition of the European STAMP Workshop and Conference ( ESWC ). The principal aim of the event was to provide a platform for the latest developments and applications of the Systems -Theoretic Accident Model and Processes (STAMP) and associated techniques, in particular, the hazard/risk analysis method STPA and the accident/ incident analysis method CAST. Under this frame, the ESWC promoted the interaction between academia, industry and governmental and other representatives in Europe.

Systemic safety management in anesthesiological practices

Anesthesiological practices are complex activities with inherent risks. Hazard assessment techniques based on cause-effect links and linear reasoning do not adequately represent the actual behavior of modern socio-technical systems, which are characterized by tight couplings and interactions among technical, human and organizational aspects. Analysing hazards following a linear perspective may result in a not completely effective management of process safety. This paper discusses the need for a systemic analysis for healthcare practices, applying such perspective to an anesthesiological process. More specifically, it aims to define process hazards, and unsafe control actions for preoperative and intraoperative anesthesiological activities, extending simple cause-effect reasoning through the System Theoretic Accident Model and Processes (STAMP) and its hazard analysis technique, i.e. System Theoretic Process Analysis (STPA). The outcomes of the study based on qualitative research techniques point out the relevance of a systemic approach, with implications for process management. It is argued that the adoption of strict procedures to constraint the variability of everyday work represents a valuable solution only for some specific tasks, while for many others variability has to be accepted as a means to enhance patient safety in a healthy work environment.

Sports-related concussion management as a control problem: using STAMP to examine concussion management in community rugby

The effective management of sports-related concussion is an on-going problem in amateur sport due to a number of systemic issues. These factors have often been studied in isolation with minimal consideration for the interactions between them, or the overall system in which they occur. The aim of this research was to model the actors, controls, and feedback mechanisms influencing the management of concussion in community rugby union using the Systems-Theoretic Accident Model and Processes (STAMP) method. Findings show that there are currently many inadequate controls, that are directly and indirectly impacting effective concussion management. The practical implications of these findings are discussed (e.g. improved guideline education, mandatory medical presence, rule amendments). Additionally, the model provides a sound framework similar team sports can use to inform research into injury management and prevention (e.g. rugby league, hockey, AFL).Practitioner Summary: Research shows that concussion management in regional sport is inconsistent due to contextual limitations. Systems-Theoretic Accident Model and Processes was applied to identify the systemic factors currently influencing concussion management practices in community sport. Findings show inadequate controls precipitate concussion management gaps. Practical implications of the findings are discussed.

Systemic approaches to incident analysis in coal mines: Comparison of the STAMP, FRAM and “2–4” models

Coal mine accidents are often caused by the coupling of multiple factors rather than by a single factor. Therefore, explaining the nonlinear and coupling characteristics in accidents by using traditional accident theory is hard. To cope with the safety challenges caused by the extensive use of digital components and the construction of complex systems, incorporating the idea of system engineering into accident analysis is deemed effective. First, this paper introduces the basic principles and analysis steps of the Systems-Theoretic Accident Model and Processes (STAMP), Functional Resonance Analysis Method (FRAM) and “2–4” models and then applies the three models to the eight coal mine accidents. Finally, the three models are compared based on their characteristics, analysis processes and analysis results. The results show that the accident causes identified by the three methods cover the main causes in the accident investigation report, and new causes were identified. However, the results of the STAMP and FRAM models are more comprehensive and systematic, but the model characteristics and analysis processes are more complex, whereas the results of the “2–4” model analysis are relatively broad, but the analysis process is simple and easy to understand. Therefore, the study suggests that although the choice of accident causing model depends on the user's knowledge level or accident type, the STAMP and FRAM models are more suitable for analyzing a small number of complex coal mine accidents, while the “2–4” model is more advantageous in the analysis of large number of accidents.

Model of Ground Handling Processes and Establishing Safety Mechanisms

<p>The following paper focuses on the operational safety issues in the aircraft ground handling process. Ground handling is a critical phase in terms of operational safety, however, severe injuries or even fatal accidents are rare. According to the available data, during a handling process a quite large number of incidents have as an outcome a damaged aircraft, which slows down the following processes and fluency of the relevant procedures. The financial costs in case of even the slightest damage are significantly high.</p><p>In order to implement different approach to safety management of ground handling companies, firstly a process analysis was performed using the Systems-Theoretic Accident Model and Process (STAMP) model. The STAMP model offers a different approach to operational safety as opposed to a traditional approach. STAMP approaches failure as a control error. The individual processes are designed for possible future STPA analysis. The processes were modelled according to the publicly available sources, and further improved with the expertise and experience from a real operation. A list of potential deviations is added to the processes or individual activities. Coordination processes between the ground handling company and the airport were also discussed. An operational measure designed to increase operational safety is proposed for selected cases.</p>

System theory based hazard analysis for construction site safety: A case study from Cameroon

IntroductionConstruction sites are known for its complex environments where many unsafe acts and/or unsafe conditions exist. Traditional risk analysis methods, such as Probabilistic Risk Analysis (PRA) deal with linear systems or component failures. These traditional techniques are not efficient to analyze nonlinear or complex systems such as construction sites. MethodThis study applied a system theory approach to a construction project risk assessment. We used a System-Theoretical Process Analysis (STPA) based on System-Theoretic Accident Model and Processes (STAMP). Data were collected in different stages. Firstly, literatures from various journal papers, articles, thesis, website and the Electricity Development Corporation of Cameroon’s (EDC) risk register were reviewed. Secondly, a case study was carried out to check the applicability of system safety to a construction project where PRA was initially used by the project team. Questionnaires were conducted on five selected project team members to get their point of view on the application of STPA. ResultThe main contribution of this approach was that by simulating more scenarios, it revealed some systematic risks that were not detected with the PRA approach such as: lack of support from the EDC stakeholders; loss of quality, security and safety when using subcontractors; and unsafe control actions by the risk manager. ConclusionTo cope with the complexity of construction projects, the STPA approach seems to produce higher quality results compared to the PRA approach since its prime aim is to simulate possible scenarios.

A STAMP-based ontology approach to support safety and security analyses

Considerations of safety and security in the early stage of system life cycle are essential to collect and prioritize operation needs, determine feasibility of the desired system, and identify technology gaps. Experts from many disciplines are needed to perform the safety and security analyses, ensuring that a system has the necessary attributes. Safety assessment is usually conducted in the concept stage. On the order hand, security assessment is performed in design stage usually when an initial architecture along with the logical and physical components are defined. Systems-Theoretic Process Analysis (STPA) is a new hazard analysis technique based on systems thinking and is built on top of a new causality model of accident, which stands for Systems-Theoretic Accident Model and Processes (STAMP), grounded in systems theory. STPA for Security (STPA-Sec) is an extension of STPA that proposes to include security concerns into the analysis. STPA-Sec helps identifying some hazardous control actions, causal scenarios, and casual factors; however, no emphasis is placed on security threat scenarios. In this paper we propose an ontology-based technique that extends STPA-Sec to improve identification of causal scenarios and associated casual factors, specifically those related to security. We propose an approach that assists safety and security experts conducting safety and security analyses using STPA-Sec with a supporting ontology. First, we present an ontology representing the safety and security knowledge through STPA-Sec process, and provide a tool that implements the proposed ontology. We then propose a process to capture safety and security knowledge into the proposed ontology to identify causal scenarios. We perform a preliminary evaluation of the ontology and the process using an aeronautic case study. The results show that the ontology-based approach helps systems engineers to identify more security scenarios compared to the case where they use only STPA-Sec. Furthermore, some hazardous control actions are not addressed if the systems engineer uses the basic STPA-Sec.

Identifying safety indicators for safety performance measurement using a system engineering approach

The paper presents a method for the development of safety indicators for a process industry application based on a system engineering perspective. Traditional approaches use probabilistic risk assessment or linear accident models which assume that accidents are linear chains of events and do not consider complex systemic factors and interactions. After BP's Texas City refinery incident, the investigation committee reported that BP had a false sense of safety performance due to providing more focus on managing personal safety rather than process safety. System engineering concepts may help the process industry to operate their activities without any severe accidents by establishing a better safety management system. This paper adopts the STAMP (System-Theoretic Accident Model and Processes) accident causation model to identify system specific indicators and also describes the proposed method with the help of a simple process industry application which is an LNG ship to ship transfer process. It compares the developed method with other methods for practical case applications. The first step of the present method is to establish the safety control structure, then safety performance indicators are identified. Further work is necessary to investigate to what degree these STAMP based indicators are complementary to indicators developed by other methods.

Complexity on the rails: A systems-based approach to understanding safety management in rail transport

Rail transport is a complex, safety-critical system which experiences catastrophic events. Systems theory-based approaches have been applied to understand risk and safety management in a range of safety-critical domains, however in rail, systems approaches have tended to be applied for accident analysis, rather than to describe how risk and safety is proactively managed. This study involved the development of a control structure model of rail transport in Australia using the Systems Theoretic Accident Model and Processes (STAMP) method. The control structure identifies the actors involved in managing safety, and shows the control and feedback mechanisms that comprise the adaptive feedback function to maintain safety. The control structure was refined in a participative process involving subject matter experts. Insights identified for improving safety management included: a need to improve feedback mechanisms to better understand the effectiveness of control measures; a lack of formal controls at higher levels of the system; and a focus within current feedback mechanisms on failures rather than understanding and learning from normal performance. Opportunities for applying the model in industry practice are also explored.

Automated inspection method for an STAMP/STPA - Fallen Barrier Trap at Railroad Crossing -

In recent years, information systems have become large and complicated, and demand for research on accident analysis of such a system and its countermeasure construction is increasing. As an accident model based on system theory, Systems Theoretic Accident Model and Processes (STAMP) has attracted many attention. In STAMP, it is not limited to malfunctions of system components and human errors, but also has feature of possibility to analyze errors of interaction among constituent elements and interaction between constituent elements and human beings. System Theoretical Process Analysis (STPA) is a method for analyzing in advance the possibility of system accident against the interaction between the controller and the controlee. More effective accident analysis can be expected by cooperation of STAMP/SPTA and model checking based on formal method. In this paper, we describe a result of STAMP analysis example of “Fallen Barrier Trap at Railroad Crossing” with automaton model checker UPPAAL. In addition, we consider an automatic detection approach between the STAMP/STPA tool STAMP Workbench and the model checker UPPAAL.

The Concept Towards a Standard Safety Model (STASAM v.0)

In safety science and practice, there have been various safety models, each of them reflecting a particular approach to safety management and accident causality. The large variety of models suggested in literature and applied in practice serve the communication of diverse perspectives towards safety and the need to consider contextual factors, but it does not allow the establishment of a common language within and across organisations and industry sectors. Considering the potential benefits of talking a lingua franca when it comes to safety and inspired by the Standard Model used in particle physics and recent suggestions from relevant studies, we thought of exploring the possibility to introduce a Standard Safety Model (STASAM). As a first step, we focused on four representative safety and accident models widely used, discussed and debated: the Swiss Cheese Model, AcciMap, Functional Resonance Analysis Method (FRAM) and Systems-Theoretic Accident Model and Processes (STAMP). We reviewed literature which compares the particular models, and we listed the strengths and weaknesses of each as a means to set the grounds for the STASAM. The combinations of these models with a focus to host their advantages and avoiding their disadvantages led to a three-level STASAM. The concept STASAM was used in two random incident investigation reports to assess its applicability and visualisation against the original models. The results of the application along with the STASAM concept were reviewed by three safety professionals and three safety researchers. The comments received were in the positive direction and indicated the potential of establishing an inclusive and commonly accepted safety/accident model. The next research phase will be the additional review of the STASAM and its pilot application to a variety of safety events and systems as a means to test its reliability and strengthen its validity.

Use of STAMP/STPA to Model Organizational Risk and Safety Management at Cruise and Ferry Companies

Recent well-publicized cruise and ferry ship accidents have been a wake-up call to the shipping industry. These events raise the need for ship owners to use more advanced risk management approaches. Enterprise Risk Management (ERM) has become an integral part of modern corporations, especially in safety critical industries where unsafe operations can lead to catastrophic accidents that result in loss of life, huge financial losses and the potential demise of the corporation. This paper presents the current findings of an on-going research to determine the best implementation of a Risk Management System (RMS) integrated with the Safety Management System (SMS) at cruise and ferry operating companies. The hypothesis is that ship management companies with better enterprise risk management will have better safety records and stronger financial performance. The paper presents the results of the application of Systems-Theoretic Accident Model and Processes (STAMP)/Systems Theoretic Process and Analysis (STPA) to a ferry operator to analyse the organizational performance of their risk and safety management systems. Initial results from the analysis showed gaps in communication paths, lack of tracking of risks and limited involvement of senior management in the risk process. A preliminary approach to deriving key indicators is presented.

Functional modeling in safety by means of foundational ontologies

Modern theory of safety deals with systemic approach to safety, formalized in form of several systemic prediction models or methods such as FRAM (Functional Resonance Analysis Method) or STAMP (System-Theoretic Accident Model and Processes). The theory of each approach emphasizes different viewpoints to be considered in approaching various industrial safety issues. This paper focuses on FRAM and its functional viewpoint for modern complex sociotechnical systems. The methodology in this paper is based on the utilization of foundational ontologies to conceptualize the core ideas of FRAM, with the focus on the concept of functions as used in theory. The outcomes of the case study in the aviation domain provide for what needs to be determined to properly model functions in FRAM and they allow for better utilization of the method in real-case applications. The results also confirm some previous research, suggesting that modern systemic approach to safety is theoretically grounded on common - or at least complementary - tenets, to be prospectively integrated by means of ontology engineering.

WebSTAMP: a Web Application for STPA & STPA-Sec

STAMP (System-Theoretic Accident Model and Processes) techniques such as STPA (System- Theoretic Process Analysis) and STPA-Sec (STPA for Security) have been applied only in an adhoc manner, without the aid of tools. More recently, tools have been proposed to help the application of STPA and STPA-Sec. Most of the tools focus on user experience issues and do not cover all the aspects of STPA and STPA-Sec. Three aspects of tools are systematization, automation and analysis completeness. Systematization allows the analysis to be performed in a more disciplined way while automation allows a more time efficient analysis. Analysis’ completeness is the analysis coverage in a given domain. We identify the essential requirements supporting business and stakeholders' needs for a STAMP based tool. We propose a STAMPcompliant web application, named WebSTAMP, for STPA and STPA-Sec. WebSTAMP is intended to aid analysts throughout the analysis process in a more automated and comprehensive way, and it aims to be a collaborative tool. We illustrate how the requirements are implemented in the current version of WebSTAMP with an example of use. The results show that WebSTAMP assists analysts to conduct safety and security analyses in a more systematic, automated and comprehensive manner.

Systems Theoretic Accident Model and Process (STAMP) applied to a Royal Navy Hawk jet missile simulation exercise

The Royal Navy uses Hawk jets to simulate sea-skimming missile attacks against vessels as part of their training regulations. To best achieve these goals, pilots of the Hawk are required to fly at approximately 50 feet above sea level to accurately mimic the flight path of a missile. Despite this need the Hawk is not equipped with a radar altimeter and instead relies upon pilot skill to ensure the safe completion of the operation. Incidents whereby the Hawk jets have struck the water are however recorded, risking pilot safety. This paper explores the Hawk missile simulation task using a Systems Theoretic Accident Model and Process (STAMP) and its corresponding hazard analysis Systems-Theoretic Process Analysis (STPA) methodology to map the key stakeholders within this operation. In doing so, the method explores areas of potential risk in the system and recommends how overall systemic safety of the operation can be improved.