Conference PaperPDF Available

Integrating Hierarchical Task Analysis into Model-Based System Design using Airbus XHTA and IBM Rational Rhapsody

Authors:
  • Airbus Defense and Space

Abstract

Hierarchical Task Analysis (HTA) is a widely used method in Human Factors to investigate human work by decomposing tasks into goal-task-subgoal-structures (Stanton, 2017). Knowledge about goals, tasks and actions of human work is fundamental to many further activities like system design, human-machine-task allocation and interface design (Hackos, 1998), as well as a prerequisite for different subsequent analysis methods, e.g. for safety purposes. A systems engineer needs to know and understand these results of Human Factors specialists’ analyses in order to respect them in the system design. In modern projects, the traditional document based specifications are often replaced by Model Based System Engineering (MBSE). Due to different applications used by Human Factors specialists and system engineers prior to this study, it was difficult to integrate the results of HTA in the model based system engineering process. We present a new tool called HTA Converter to integrate a Hierarchical Task Analysis defined in Airbus xHTA into an IBM Rational Rhapsody project to bridge the tooling gap between the different departments. This has advantages for the development process and can lead to better products that are easier to operate even under very difficult conditions.
Hierarchical Task Analysis (HTA) is awidely used method in
Human Factors to investigate human work by decomposing
tasks into goal-task-subgoal-structures (Stanton et al., 2017).
Knowledge about goals, tasks and actions of human work is
fundamental to many further activities like system design,
human-machine-task allocation and interface design (Hackos
and Redish, 1998)as well as a prerequisite for different
subsequent analysis methods for e.g. safety purposes.
A systems engineer needs to know and understand these
results of Human Factor specialists analyses in order to
respect them in the system design.
[Hackos and Redish, 1998] Hackos, JoAnn T., and Redish, Janice. “User and task analysis for interface design.”, 1998.
[Rabl et al., 2018] Rabl, Alexander N., et al. “DONT PANIC! Perform Complex Hierarchical Task Analysis with the Airbus eXtended HTA tool” in Proceedings of the
33rd Conference of the European Association of Aviation Psychology, 2018.
[Stanton et al., 2017] Stanton, Neville A., et al. “Human Factors Methods: a Practical Guide for Engineering and Design.” Taylor and Francis, 2017.
Fig. 1 uses graphics from openclipart.org that are released in the Public Domain (cliparts 194773, 192787, 34189, 155107, 182517, 192858, 276861).
According to Rabl et al. (2018) a Hierarchical Task
Analysis in Airbus XHTA consists of two seperate parts,
one single Structure and one or multiple Plans.
The structure represents the strictly hierarchical
relationship of goals, tasks and actions. All subelements
of a certain level are either neccessary and/or sufficient
to achieve the target state of said level. In Airbus XHTA
Plans, all elements of the Structure are connected by
different logical flow controls in order to create a activity-
diagram like overview of the goal-task structures.
Integrating Hierarchical Task Analysis into Model-Based System
Design using Airbus XHTA and IBM Rational Rhapsody
Jakob Rott1, Julian Weixler1, Alexander Rabl2, Peter Sandl2, Mario Weiß3, Birgit Vogel-Heuser3
1Technical University of Munich, Department of Informatics, Munich, Germany
2Airbus Defence and Space, Human Factors Engineering and Flight Deck GE, Manching, Germany
3 Technical University of Munich, Department of Mechanical Engineering, Munich, Germany
Introduction
Translation of XHTA to SysML Example of HTA conversion
Airbus
XHTA
System
Engineers
Human Factors
Specialists
IBM Rational
Rhapsody
joint work requires high
effort in communication
respect e.g.
psychologic
al effects
use individual
software
holistic
view on
system
use
standard
software
Fig. 1. System Engineers and Human Factors Specialists working on the same project.
References
Conclusion
The HTA Converter offers a possibilty to covert HTAs to a SysML representation. The specialized data model of Airbus XHTA
is persisted in a standardized language.This work can have an impact on system engineering to ensure Human Factors
findings are adequately respected and eases the communication between the involved system engineering disciplines.
Future Work
In modern projects the traditional document based
specifications are often replaced by Model Based System
Engineering (MBSE).Due to different applications used
by Human Factors specialists and system engineers prior
to this study it was difficult to integrate the results of HTA
in the model based system engineering process.
We present a new tool called HTA Converter to integrate a
Hierarchical Task Analysis defined in Airbus XHTA into an
IBM Rational Rhapsody project to bridge the tooling gap
between the different departments.This has advantages
for the development process and can lead to better
products that are easier to operate even under very
difficult conditions.
For both,the Structure as well as the Plans, a direct
mapping was established linking XHTA logical elements
to IBM Rational Rhapsody SysML elements (see Tab le
1). To recreate the Structure, a block definition diagram
was utilised. To mirror XHTAs Plans, SysML Activity
diagrams were employed (see Figure 3).
The mapping of XHTA to IBM Rational Rhapsody models
formally mirrors all data,the Human Factors Analyst has
brought into the model.Yet,we want to assess the
benefits of importing HTA results in system engineering
tools both on the level of the Human Factors as well as
on the systems engineering process.
Further, modeling tools beside IBM Rational Rhapsody
should be supported. This way,the knowledge about
human work can be dispersed in abroader way and aid
system design more holistically.
IEEM18-P-0259
Fig. 2. Upper picture shows the Structure of an HTA in Airbus XHTA. Lower Picture is the translation in IBM
Rational Rhapsody using a Block Definition Diagram.
The example illustrates a simplified HTA Fuel Imbalance containing
tasks regarding the situation of imbalenced fuel levels. The
hierarchical Structure of the HTA as visualized in Airbus XHTA is
shown in Figure 2upper picture. The Structure on the level below
the main task consists of six tasks.
After importing the output XML file
generated by the HTA Converter in IBM
Rhapsody, the user can create a Block
Definition Diagram (BDD) and include the
Structure elements.The BDD then
contains all tasks created in the XHTA
Structure with their hierarchy illustrated
by composition relations (Fig.2,lower).
The Plan (Fig.3,left)of the sample HTA
is converted to an activity diagram (Fig. 3,
right). For each reference from an
element in the Plan to the corresponding
task in the Structure a Call Behavior is
created as described in Tab le 1.
Fig. 3. Left picture shows a plan of a sample project in Airbus XHTA. The right picture shows the same plan
converted to an activity diagram in IBM Rational Rhapsody.
Airbus XHTA element
Translation in SysML
Tasks
(in Structure)
Action elements with stereotype “HTAActivity”
Plans
(general)
Activity
Diagrams
Tasks
(in Plans)
Call Behaviors (CBs)
Linear
Flow
Connection of CBs with Control Flows (CFs)
Selection & Branching
Flow
Decision- and merge nodes
Guards on CFs
Cyclic
Loop Flow
Begin: Merge Node, End: Decision Node
CF back to cycle‘s begin
Jump
to Anchor Flow
CF to Anchor‘s position
Non
-Linear Flow
Interruptible region
Fork-and join nodes
Parallel
Flow
Fork
-and join nodes
Plan
-in-Plan
(nested Plans)
Activity Diagrams
CB in originating Plan to Plan-in-Plan-Activity
Diagram
Properties
Stereotype
containing each property as a tag
Tab l e 1. T h e mappings from Airbus XHTA elements to SysML elements.
... Recent efforts have employed UCD and associated methods to improve human-system performance in aerospace applications. Various types of task or functional analyses (and other model-based representations of user work) have made impacts on manned flight, air traffic control, and control of unmanned aerial systems [15,16]. Similarly, other recent research has investigated the use of novel HMIs such as speech-to-text capabilities [17] and lighting-or gesture-based communications [18]. ...
Article
Full-text available
The prevalence of unique, disparate satellite command and control (SATC2) systems in current satellite operations is problematic. As such, the United States Air Force aims to consolidate SATC2 systems into an enterprise solution that utilizes a common Human–Machine Interface (HMI). We employed a User-Centered Design (UCD) approach including a variety of methods from design thinking and human factors engineering to develop a solution that is effective, efficient, and meets operator needs. During a summative test event, we found that users had significantly higher situation awareness, lower workload, and higher subjective usability while using the HMI developed via UCD over the existing, or legacy, HMI. This case study serves as evidence to support the assertion that involving users early and often has positive and tangible effects on the development of aerospace systems.
... A necessary step in such human-centered design approaches is to decompose the job assignments into subtasks (Stanton et al., 2013) in order to enable a fine-grained analysis of individual activities, and also to identify the objects with which the worker interacts. Most workflows employing DHMs (Stanton, 2006) for this purpose typically lack modularity to modeling new objects and actions as well as automation (Rott et al., 2018). The presented framework is built to address the lack of linkage between the real-time execution of training scenarios in VR and the offline optimization of ergonomics through a DHM-based approach. ...
Article
Full-text available
The use of virtual reality (VR) techniques for industrial training provides a safe and cost effective solution that contributes to increased engagement and knowledge retention levels. However, the process of experiential learning in a virtual world without biophysical constraints might contribute to muscle strain and discomfort, if ergonomic risk factors are not considered in advance. Under this scope, we have developed a digital platform which employs extended reality (XR) technologies for the creation and delivery of industrial training programs, by taking into account the users and workplace specificities through the adaptation of the 3D virtual world to the real environment. Our conceptual framework is composed of several inter-related modules: 1) the XR tutorial creation module , for automatic recognition of the sequence of actions composing a complex scenario while this is demonstrated by the educator in VR, 2) the XR tutorial execution module , for the delivery of visually guided and personalized XR training experiences, 3) the digital human model (DHM) based simulation module for creation and demonstration of job task simulations avoiding the need of an actual user and 4) the biophysics assessment module for ergonomics analysis given the input received from the other modules. Three-dimensional reconstruction and aligned projection of the objects situated in the real scene facilitated the imposition of inherent physical constraints, thereby allowed to seamlessly blend the virtual with the real world without losing the sense of presence.
Article
Human systems integration (HSI) involves Human Factors and Ergonomics (HFE), Human-Machine Interaction (HMI), engineering, and domain experience, which are the initial components of systems engineering (SE) in all industries' economies: wellbeing, transportation, energy, IT, retail, finance, manufacturing, and production. HSI can be achieved by combining virtual prototyping with Human-In-the-Loop (HIL) simulations. HMI is typically a model-based and patented innovation; it uses HIL and requires a homogenized systemic reflection with feedback. Virtual Reality (VR) Human-Centered Design (HCD) is sustainable. VR-controlled HCD acts as a definitive Key Enabling Technology (KET) concept in considering the full range of system Life Cycle Assessments (LCAs) and whether the process is sustainable. To this end, on the planet earth, human organizational elements are not only assessed during the design process but the whole LC of a system. Against intuitive education, it has been stated that conservative and narrow LCA should not be implemented in a sustainable world but instead Cradle-to-Cradle (C2C) design from social, economic, or environmental terms; the objective is to increase positive impacts, not reduce negative ones as in LCA. By enabling virtual environments, digital tools enable these new capabilities, which should be realized as sustainable by Digital Twin (DT) formable as a Sustainable Model Based HSI (SMBHSI) concept with high-level Artificial Intelligence (AI) and C2C consideration forming the level of the metaverse, straining from VR. DT-based Internet of Things (IoT) solutions enable investigators to test scenarios for future foresight, give corporations abilities to benefit from performance metrics based on domain experience, and are a crucial concept in SMBHSI. A case on this proceeding instance will display an example for SMBHSI when the method is scoping review to the strategic objective to form an up-to-date linear outlook. Integrating HSI on AI and C2C thinking methodologies helps to save resources and move towards the globalized green level of circular economies, representing the economic integration of the economy of the human system by indirect resources utilization suggestion as indicative as inference and adaptation to blockchains.
Article
Traditional product development frameworks were developed decades ago, lacking the utilization of big data technology and model-based systems engineering (MBSE) theory. This paper proposes a data and model-based triple V framework based on the traditional V framework and double V framework, covering lifecycles of the product, model, and data. By mapping the Harmony methodology and adding data analysis methods to the triple V framework, a structured methodology of the framework is constructed. This paper applies the proposed framework and its methodology in designing a damage control system (DCS) based mission system and then verifies the new framework’s efficiency.
Chapter
Full-text available
Complex systems pose unprecedented challenges for system architects and engineers. In particular, they require multi-disciplinary approaches to manage system complexity from conception to verification and validation. Model Based System Engineering offers system architects and engineers a systematic framework to develop and use both descriptive and analytical models, to analyze and design systems. To meet human machine interaction and fault tolerance requirements, common semantics are needed to ensure effective and unambiguous communication among systems architects, safety/supportability engineers, and human factors engineers. This paper presents how MBSE can be extended for effective human-machine interaction and fault-tolerant design.
Thesis
Full-text available
Aircraft developers like other development and manufacturing companies, are experiencing increasing complexity in their products and growing competition in the global market. One way to confront the challenges is to make the development process more efficient and to shorten time to market for new products/variants by using design and development methods based on models. Model Based Systems Engineering (MBSE) is introduced to, in a structured way, support engineers with aids and rules in order to engineer systems in a new way. In this thesis, model based strategies for aircraft and avionics development are studied. A background to avionics architectures and in particular Integrated Modular Avionics is described. The integrating discipline Systems Engineering, MBSE and applicable standards are also described. A survey on available and emerging modeling techniques and tools, such as Hosted Simulation, is presented and Modeling Domains are defined in order to analyze the engineering environment with all its vital parts to support an MBSE approach. Time and money may be saved by using modeling techniques that enable understanding of the engineering problem, state-of-the-art analysis and team communication, with preserved or increased quality and sense of control. Dynamic simulation is an activity increasingly used in aerospace, for several reasons; to prove the product concept, to validate stated requirements, and to verify the final implementation. Simulation is also used for end-user training, with specialized training simulators, but with the same underlying models. As models grow in complexity, and the set of simulation platforms is expanded, new needs for specification, model building and configuration support arise, which requires a modeling framework to be efficient.
Book
Full-text available
Human Factors Methods: A Practical Guide for Engineering and Design presents more than ninety design and evaluation methods, and is designed to act as an ergonomics methods manual, aiding both students and practitioners. The eleven sections of the book represent the different categories of ergonomics methods and techniques that can be used in the evaluation and design process. Offering a 'how-to' text on a substantial range of ergonomics methods that can be used in the design and evaluation of products and systems, it is a comprehensive point of reference for all these methods. An overview of the methods is presented in chapter one, with a methods matrix showing which can be used in conjunction. The following chapters detail the methods showing how to apply them in practice. Flowcharts, procedures and examples cover the requirements of a diverse audience and varied applications of the methods. The final chapter presents a case study of methods being used together in a system evaluation project.
Article
Full-text available
This paper gives an overview of the development of the field of Knowledge Engineering over the last 15 years. We discuss the paradigm shift from a transfer view to a modeling view and describe two approaches which considerably shaped research in Knowledge Engineering: Role-limiting Methods and Generic Tasks. To illustrate various concepts and methods which evolved in recent years we describe three modeling frameworks: CommonKADS, MIKE and PROTÉGÉ-II. This description is supplemented by discussing some important methodological developments in more detail: specification languages for knowledge-based systems, problem-solving methods and ontologies. We conclude by outlining the relationship of Knowledge Engineering to Software Engineering, Information Integration and Knowledge Management.
Conference Paper
Full-text available
If UML activity diagrams are to succeed as a standard in the area of organisational process modeling, they need to compare well to alternative languages such as those provided by commercial Workflow Management Systems. This paper examines the expressiveness and the adequacy of activity diagrams for workflow specification, by systematically evaluating their ability to capture a collection of workflow patterns. This analysis provides insights into the relative strengths and weaknesses of activity diagrams. In particular, it is shown that, given an appropriate clarification of their semantics, activity diagrams are able to capture situations arising in practice, which cannot be captured by most commercial Workflow Management Systems. On the other hand, the study shows that activity diagrams fail to capture some useful situations, thereby suggesting directions for improvement.
Article
Full-text available
A Unified Modeling Language/Systems Modeling Language (UML/SysML) subset was the modeling notation selected for an aerospace systems engineering project at Saab Aerosystems. In this paper, the rationale for selecting UML/SysML is given, along with a description of the situation at the project planning stage regarding business conditions, method and tools support. The usage of use case, sequence, and activity diagrams are described as well as definition of functional chains with SysML. Furthermore, the connections to system implementation activities including code generation and simulation are discussed. The advantages and disadvantages of using UML/SysML from experience in an industrial context are reported. It is also described how UML/SysML is related to industrial research projects in the Model Based Systems Engineering (MBSE) methods and tools area. Introducing UML/SysML with a methodology and a supporting toolset in an operative organization require a clear strategy, including planning, just-in-time training, and mentor support. Finally, industrial needs for further development of SysML are discussed. © 2009 Wiley Periodicals, Inc.
Article
New weapons being developed for modern military forces feature advanced technology designed to extend and improve mission performance beyond the capability of existing systems. For example, aircraft systems are being developed with advanced technology designed to extend range, increase speed, provide for more precise navigation, avoid enemy threats, and acquire and engage enemy targets at night or in adverse weather.