Using Models to Assure Emergent Behaviors in Railway Transportation Networks


Railway transportation networks are complex systems of systems which exhibit emerging behaviors. Emergence is the property that distinguishes a collection of things from a system which provides a behavior not attainable by any subset of system constituents. At the railway network level, the necessity of proving the desired emerging behaviors, revealing undesired patterns of behavior, and providing evidence that the rate of occurrence of a particular undesired one is below a specific threshold is stated in the RAMS standard. This short paper briefly discusses different aspects of this approach and elaborates on a successful example.

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Review: Rasmussen’s 1997 paper – Risk management in a dynamic society: A modeling problem

The article by Rasmussen (1997) begins with an introduction that risk management is treated differently across all relevant hierarchical levels of a socio-technical system. However, due to the dynamics of the system, treating risk-related decision-making in isolation does not enable us to recognize when we cross the boundary of safe operation. Thus, when assessing risks in a complex socio-technical system, we have to include the layers of legislation, management, work planners and system operators. As a result, we need to touch upon risk models of the disciplines varying from economics, organizational theories and cognitive psychology to engineering.

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Introduction-Mohsen Jafari

Research Fellow

Mohsen Jafari is Post-doc Research Fellow, who has joined the SIRA project since May 1st 2019. Prior to that, he was Research Fellow at the University of Twente (Faculty of Behavioural, Management and Social Sciences), and was involved in doing research and teaching on topics related to the economic evaluation of healthcare technologies.    

Mohsen has done both his BSc and MSc degrees in Industrial Engineering at Sharif University of Technology, and University of Tehran, respectively. 

Afterwards, he had been working as Project Coordinator, Planner, and Systems Analyst in different industries for 3-4 years in Tehran/Iran. Mohsen also holds a Ph.D. in Operations and Technology Management from the University of Melbourne (Australia). His research interests are innovation, technology management, product development, operations management, and computational social science. His e-mail address is

Reflection on the key developments on the organizational knowledge creation theory

Theoretical Background
The organization knowledge creation theory was first developed by Nonaka, (1994) that explained the conversion of tacit and explicit knowledge into organizational knowledge and presented four modes of knowledge conversion that are as follows:

  1. Tacit to tacit
  2. Explicit to explicit
  3. Tacit to explicit
  4. Explicit to tacit
Nonaka, (1994) advocated that “the key to acquiring tacit knowledge is experience” and called the process of creating tacit knowledge through shared experience socialization. In addition to this, he stated that “socialization is connected with theories of organizational culture”. 
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A review of ISO/IEC/IEEE/DIS 21840 Systems and software engineering – Guidelines for the utilization of ISO/IEC/IEEE 15288 in the context of System of Systems (SoS) engineering

This post reviews ISO/IEC/IEEE/DIS 21840 Systems and software engineering – Guidelines for the utilization of ISO/IEC/IEEE 15288 (NEN-ISO/IEC/IEEE 15288, 2015) in the context of System of Systems (SoS) engineering. A draft of this document is circulated for comments and approval. The document is therefore yet subject to change and might not yet be referred to as an international standard until published as such[1]. While (NEN-ISO/IEC/IEEE 15288, 2015) applies to systems (including constituent systems), this document provides guidance on the application of these processes to SoS. The scope of the (draft) standard is the same as (NEN-ISO/IEC/IEEE 15288, 2015), which establishes a common framework of process descriptions for describing the life cycle of systems created by humans.  It defines a set of processes and associated terminology from an engineering viewpoint.  These processes can be applied at any level in the hierarchy of a system’s structure.  Selected sets of these processes can be applied throughout the life cycle for managing and performing the stages of a system’s life cycle.  This is accomplished through the involvement of all stakeholders, with the ultimate goal of achieving customer satisfaction, hence addresses more than system engineering activities. In addition it explores the similarities and differences between systems and SoS and, by extension, the similarities and differences between engineering of systems and SoS.