PPI SyEN 61 A1

Object-Process Methodology, OPM ISO 19450 – OPCloud and the Evolution of OPM Modeling Tools


Dov Dori1,2, Ahmad Jbara1,3, Natali Levi1, and Niva Wengrowicz1

1 Technion, Israel Institute of Technology

2 Massachusetts Institute of Technology

3 Netanya Academic College


We provide an overview of Object-Process Methodology – OPM ISO 19450, focusing on its underlying philosophy and principles. We then describe a recent experience of Volvo Cars Corporation in search of a modeling language, which culminated in the adoption of OPM. The focus of the paper moves to describing the evolution of past, present, and future OPM modeling tools with a real-life complex example of an OPM model of a system prepared with a leading Gas Turbine manufacturer for Gas Turbine Designing, aimed at cutting to one third the time to respond to an RFP. We conclude with a partial list of industrial applications and outlook for OPCloud development and its envisioned role in advancing MBSE.

Web sites: http://esml.iem.technion.ac.il/ and https://www.opcloud.tech/

Email:  dori@mit.edu

Copyright © 2017 by Dov Dori.  All rights reserved.


Object-Process Methodology, OPM (Dori, 2002; 2016), ISO 19450 (ISO 19450, 2015), is a holistic formal yet intuitive conceptual modeling approach to the development of complex socio-technical systems and knowledge management. OPM is both a language and a methodology. The OPM language part is defined by the specification of its syntax, semantics, and ontology. The OPM methodological part is the specification of recommended approach to using the OPM language for modeling complex systems, and is therefore applicable to model-based systems engineering (MBSE) and to capturing and managing scientific, engineering, and any other kind of knowledge.

The OPM language is bimodal—it uses both graphics—a single diagram kind, Object-Process Diagram (OPD), and natural language text—Object-Process Language (OPL), to represent knowledge at various, interconnected levels of detail about the major aspects of any system: function, structure, and behavior. Due to its compact, general ontology, its single diagram kind, in stark contrast with UML (OMG UML 2.2, 2009) and SysML (OMG SysML 1.5, 2017), its bimodal representation, its ease of learning and implementation, and its generality, OPM is most suitable to serve as the underlying modeling language for MBSE.

The graphical and the textual OPM modalities are semantically equivalent and represent the same model. A set of hierarchically structured, interrelated Object-Process Diagrams (OPDs) constitutes the graphical model, and a set of automatically generated sentences in a subset of the English language constitutes the textual model expressed in Object-Process  Language  (OPL). In a graphical-visual model, each OPD consists of OPM elements, depicted as graphic symbols, sometimes with label annotation. The OPD syntax specifies the consistent and correct ways to manage the arrangement of those graphic elements. Using OPL, OPM generates the corresponding textual model for each OPD in a manner that retains the constraints of the graphical model. Since the syntax and semantics of OPL are a subset of English natural language, domain experts easily understand the textual model.

OPM as ISO 19450 (2015). In December 2015, the International Organization for Standardization (ISO) recognized OPM as ISO 19450. Since then, leading industries in the domains of aerospace, car manufacturing, home appliance manufacturing, insurance, and defense have adopted OPM and are applying it for such objectives as managing knowledge, developing a new generation of product systems, and technology road mapping.

As noted in ISO 19450, OPM notation supports the conceptual modeling of systems via formal syntax and semantics. This formality serves as the basis for model-based systems engineering (MBSE) in general, including systems architecting, engineering, development, life cycle support, communication, and evolution. OPM facilitates a common view of the system under construction, test, integration, and daily maintenance, providing for working in a multidisciplinary environment. Furthermore, the domain-independent nature of OPM opens system modelling to the entire scientific, commercial and industrial community for developing, investigating, and analyzing manufacturing and other industrial and business systems within their specific application domains. This enables companies to merge and provide for interoperability of different skills and competencies into a common intuitive yet formal framework. Moreover, using OPM, companies can improve their overall, big-picture view of the system’s functionality, flexibility in assignment of personnel to tasks, and managing exceptions and error recovery. System specification is extensible for any necessary detail, encompassing the functional, structural, and behavioral aspects of a system. As noted, especially since the recognition of OPM by ISO as ISO 19450, there is growing interest and demand for using OPM among large, international Fortune 500 companies, including technology, insurance, banking, and large-scale national agencies. Some request to remain in the shadow for now, as they deem it a competitive advantage to use OPM. The following case in point (Törmänen et al. 2017) exemplifies this trend.

In Search of a Modeling Language: The Volvo Experience. Working in Volvo Cars Corporation, Törmänen et al. (2017) searched for a language to generate an information model that takes into account different contexts of car design, from user requirements to optimization requirements. They required that the language be intuitive, self-explainable, easily learned by new users, and general, so it can model all the aspects of the product. They checked various systems engineering modeling languages including IDEF0 (Defense Acquisition University Press, 2001), UML, SysML and Modelica. They found that IDEF0 works for processes but not for structural diagramming. UML and SysML were found to be flexible multi-purpose languages, but had a “big drawback” of not being intuitive for non-experts, and their models “easily become quite messy.” Modelica can model behavior and structure, but it requires non-experts to make considerable effort to learn and understand. They then note: “The Eureka moment came when we ran into Object Process Methodology (OPM) with its universal minimal ontology describing the world with things and things that happen, i.e. stateful objects that exist and processes that can transform them. It is much leaner than SysML and thereby becomes easier to understand and practice for newcomers.” (p. 8).

The Evolution of OPM Modeling Tools

While it is possible to use a modeling language with a pencil and paper (or basic drawing software), it was clear from the outset that to do serious modeling and analysis, a computer-aided software engineering (CASE) tool that supports the language is mandatory. In this section, we describe the evolution of the three main tools developed for OPM modeling: the past OPA CASE Tool, the current OPCAT, and the future OPCloud.

OPA CASE Tool – A Historical Perspective

As early as 1998, only three years after the first paper on OPM (Dori, 1995), then called OPA for Object-Process Analysis, was published, two undergraduate students at the Technion took the initiative and developed in Visual Basic an OPM modeling tool called OPA CASE Tool. Figure 1 shows a screenshot with the graphic user interface (GUI) of OPA CASE Tool version 1.7. The tool was quite rudimentary, with a single level of detail, and it did not generate OPL. The model shows the process OPM Modeling, which requires the two parts of OPM – OPM Language and OPM Methodology. The Modeler is the (human) agent and the result is the OPM Model, which comprises of OPD Set – the graphic modality of the model, and OPL Spec – the textual modality of the model. We use the same OPM model to demonstrate the next two OPM modeling tools, OPCAT and OPCloud.

Figure 1. A screenshot of OPA CASE Tool 1.7 (1998)

OPCAT – The Horsepower of OPM Modeling

A couple of years after the introduction of OPA CASE Tool, we started developing OPCAT, short for Object-Process CASE Tool. Presently, OPM modelers use OPCAT (Dori et al., 2010), a freely web- available Java-based OPM modeling software desktop tool1[1].

OPCAT was first presented in July 1998 at ECOOP’98 (Sturm & Dori, 1998). It may be interesting to read that the philosophy of OPM was already in place then:

“The underlying observation of the Object-Process paradigm is that everything in the universe of interest is either a process or an object. This opens the door for the possibility of modeling a system using a single model that faithfully defines and describes both its structure and behavior. These two major aspects of any system are represented without suppressing one another. Structural relations – primarily aggregation, generalization and characterization – and procedural relations, which model the behavior of the system over time, are seamlessly intertwined to provide a comprehensive understanding of the system.”

A few months later, we presented OPCAT in OOPSLA’98 (Dori & Sturm, 1998). Since UML, Unified Modeling Language (OMG UML 2008), had been adopted a year earlier, we discussed the main difference between the OPM approach and that of UML, namely the model multiplicity of UML vs. the model singularity in OPM:

“Object-Process Methodology (OPM) is a system development approach that integrates structure and behavior of the system within a single unifying model. The conventional wisdom has been that there is an inherent dichotomy between object- and process-oriented approaches, and that it is not possible to combine these two essential aspects of any system into one coherent integral frame of reference. This misconception has accompanied systems analysis to the extent that even the accepted UML standard (Booch and Rumbaugh, 1995, 1996) maintains the separation between structure and behavior, and spreads analysis activities across no less than eight types of models that use different diagram types.”

[1] OPCAT is downloadable freely from http://esml.iem.technion.ac.il/opcat-installation/

Figure 2. The GUI of OPCAT showing the process OPM modeling and the involved object set

Figure 2 shows the GUI of OPCAT 4.2 using the same system model as in Figure 1. Figure 3 is an OPM model of Gas Turbine Designing in a large corporation whose motivation was to reduce the Proposal Production Rate in response for an RFP from the current 6-18 months to 4-6 months. Figure 3 shows detail level 1 (SD1), where the process Gas Turbine Designing is in-zoomed, exposing four subprocesses: Researching, Conceptual Designing, Detailed Designing, and Design for Manufacturing.

Figure 3. OPM model of Gas Turbine Designing – Detail level 1 (SD1) – Gas Turbine Designing in-zoomed

The automatically generated OPL sentence expressing the benefit of the system is in line 3 from the bottom of Figure 3:

Detailed Designing (Stage One) changes Gas Turbine Architecture from technologically viable to

commercially viable and Proposal Production Rate from 6-18 months to 4-6 months.

This OPL sentence also expresses the fact that the same process changes Gas Turbine Architecture from technologically viable to commercially viable, as also expressed in the OPD.

OPCAT enables visual modeling and model simulation via concurrent, synchronous, and discrete time execution (Yaroker et al., 2013). The execution enables understanding the system’s behavior and the detection of modeling errors by analyzing the mechanisms underlying the system under study. As an example, Figure 4 shows the process Conceptual Designing (Stage Zero), which appeared as a subprocess in Figure 3, in-zoomed during OPCAT’s animated simulation, showing Whole Engine Designing (WED) currently executing, as marked by the dark purple. This process is currently generating the object Structural & Mechanical Requirements Set. At the bottom of Figure 4, we can see the lifespan graph – a graph showing the state of each object and process at each step of the simulation. Currently, the animated simulation is at step 2 and Whole Engine Designing (WED) is marked as being active.

Figure 4. The process Conceptual Designing (Stage Zero) from Figure 3 in-zoomed during OPCAT’s animated simulation, showing Whole Engine Designing (WED) currently executing

OPCloud – The Even Brighter Future of OPM Modeling

While OPCAT has been evolving and serving the OPM community for well over a decade, it is time for moving to the next generation of MBASE modeling tools, which is Cloud based. Indeed, last year we started developing OPCloud (https://www.opcloud.tech/), a collaborative OPM modeling tool, which is invoked by a URL so it requires no program installation. Figure 5 presents the current OPCloud GUI with the same model of OPM Modeling shown in OPCAT in Figure 2 and in OPA CASE Tool in Figure 1.

Figure 5. The current OPCloud GUI

Besides being cloud-based and enabling real-time collaboration, OPCloud has many novel features that distinguish it from OPCAT. One such feature is exemplified in Figure 5: While hovering over an OPL sentence, the OPD construct (a set of things, i.e., objects and processes, connected by a link) is highlighted. In Figure 5, the highlighted sentence causes the process  OPM  Modeling  and  the  object  OPM  Methodology,  as  well  as  the  instrument  link connecting them, to also be highlighted in the OPD. The reverse shall be true as well: Hovering over a link shall highlight the OPL sentence  and also present (or utter) it in a note in the OPD.

OPM uniquely distinguishes between physical and informatical things (objects or processes), enabling the generation of executable code from the informatical things and relations, alongside simulation of the hardware components, which the software expressed informatically in the model, controls. After conceptual modeling, the same OPCloud framework shall enable moving seamlessly back and forth between conceptual modeling and detailed design by gradually refining the system and introducing into it computational elements. The simulated execution shall combine the auto- generated software with the modeled hardware components, providing for a complete, system-level emulation. Developers will be able to gradually replace modeled hardware components by real prototypical parts, and the software modules that control them will evolve to reflect required needs as they are revealed from the hardware operation.

Epilogue – Testimonials

In response to a few questions, Major (Retired) Rafael Vila, United States Air Force, wrote on October 2, 2017:

How I learned about OPM?

As part of my duties as a Joint Test Officer in 2008, I was required to follow the Department of Defense Architecture Framework (DoDAF, Version 1.5) in support of test and evaluation activities. An essential part of this work was interpreting DoDAF artifacts to develop effective interoperability testing strategies. DoDAF was complex, and project managers consistently struggled to deliver valuable architectural data. … As a result I began to explore alternatives, and in 2009 and I ran into Professor Dori’s Object Process Methodology (OPM) text.

My experience with OPM, how it is, or can be, applied in industry or in academia, and specifically at my place or work

Almost 10 years later, I still … apply OPM as a simple analysis method to consistently identify and model top level functionality, supporting instruments, and agents required to deliver mission critical outcomes.

What is the potential contribution of OPM to MBSE?

OPM can bring much needed simplicity and structure to improve the acquisition of IS. … OPM can begin to bridge the gap between thinkers, doers, and talkers—their respective inputs are critical, but their interactions must be optimized.

What are the challenges in adopting MBSE in general and OPM in particular? Is OPM easier or more challenging than other approaches?

OPM is simple, elegant, and powerful in the right hands. The biggest challenge facing OPM is breaking into governments and private entities as Free and Open Source Software (FOSS).

Ricardo Moraes, a Systems Engineer, Aircraft Safety and Security for Embraer S/A Commercial Aviation Company, wrote on Sept. 26, 2017:

My experience with OPM, how it is, or can be, applied in industry?

I conduct an OPM application in the study scenario on the air management system and the experience was very good. OPM helped with Generalization-specialization and inheritance structural relations in the brainstorm and abstraction level of the functionalities analysis that help us understand in “big picture” and contributes to the robustness of the architecture.

What is the potential contribution of OPM to MBSE?

OPM contributions to MBSE in early phases … to quickly understand and provide analysis and solutions. OPM increases productivity … by minimizing unnecessary manual transcription of concepts when coordinating the work of a multidisciplinary team.

What are the challenges in adopting MBSE in general and OPM in particular?

I see OPM as complementary for brainstorming. OPM makes the context diagrams much easier than SysML and brings a global view where System Architects do not worry about details. However, OPM has just a few notations and this can create difficulty in sustaining the models during the development phases.

Summary and Conclusions

Since the first paper on OPM (Dori, 1995), two books (Dori 2002; 2016) and dozens of papers have been published in a large variety of multidisciplinary human-made socio-technical industrial and information systems, as well as biological systems. Domains that have applied OPM include molecular biology (Somekh et al., 2014), medicine (Wachs et al., 2014), satellite communication software development (Dori & Thipphayathetthana, 2015), socio-technical systems (Osorio et al., 2011), data warehousing (Dori et al., 2008), agent technology (Sturm et al., 2010), and aerospace (Mordecai et al., 2016).

This partial list demonstrates the universality of the OPM underlying philosophy of minimalism and employing the smallest possible set of conceptual building blocks: Stateful objects and processes that transform them. Small is beautiful, and if we aspire to stand a chance in tackling the design and lifecycle support of ever more complex systems, the use of a simple yet powerful conceptual modeling language is a must. Equally important is the availability of an excellent modeling tool that acts as a smart apprentice of the system engineering employing MBSE. This principle is guiding us as we are developing OPCloud, and we expect it to be functional and available before the end of 2018. ISO 19450 OPM provides a complete guide to tool vendors, and we hope to see more OPM modeling tools developed in the near future, as OPM usage keeps increasing and becoming the conceptual modeling language and methodology of choice.

List of Acronyms Used in this Paper

Acronym         Explanation

CASE              Computer-Aided Software Engineering

MBSE              Model-Based Systems Engineering

OPM                Object-Process Methodology

OPD                Object-Process Diagram

OPL                 Object-Process Language

OPCAT           Object-Process CASE Tool

OPCloud         Object-Process Cloud (CASE Tool)

OMG               Object Management Group

SysML             Systems modeling Language

UML                Unified Modeling Language


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