Stef Janssen

Mr. Stef Janssen

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Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 November 2019 in Simulation Modelling Practice and Theory
Verified
Journal Article
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SJStef Janssen
Stef Janssen
ASAlexei Sharpanskykh
Alexei Sharpanskykh
RCRichard Curran
Richard Curran
KLKoen Langendoen
Koen Langendoen

29 May 2020 in Aerospace
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Journal Article
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SJStef Janssen
Stef Janssen
RSRégis van der Sommen
Régis van der Sommen
ADAlexander Dilweg
Alexander Dilweg
Alexei  SharpanskykhAlexei Sharpanskykh
Alexei Sharpanskykh
Airport security checkpoints are the most important bottleneck in airport operations, but few studies aim to empirically understand them better. In this work we address this lack of data-driven quantitative analysis and insights about the security checkpoint process. To this end, we followed a total of 2277 passengers through the security checkpoint process at Rotterdam The Hague Airport (RTM), and published detailed timing data about their journey through the process. This dataset is unique in scientific literature, and can aid future researchers in the modelling and analysis of the security checkpoint. Our analysis showed important differences between six identified passenger types. Business passengers were found to be the fastest group, while passengers with reduced mobility (PRM) and families were the slowest two groups. We also identified events that hindered the performance of the security checkpoint, in which groups of passengers had to wait long for security employees or other passengers. A total of 335 such events occurred, with an average of 2.3 passengers affected per event. It was found that a passenger that had a high luggage drop time was followed by an event in 27% of the cases, which was the most frequent cause. To mitigate this waiting time of subsequent passengers in the security checkpoint process, we performed an experiment with a so-called service lane. This lane was used to process passengers that are expected to be slow, while the remaining lanes processed the other passengers. It was found that the mean throughput of the service lane setups was higher than the average throughput of the standard lanes, making it a promising setup to investigate further.

5 February 2019 in Risk Analysis
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Journal Article
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SJStef Janssen
Stef Janssen
ASAlexei Sharpanskykh
Alexei Sharpanskykh
RCRichard Curran
Richard Curran
Security risk management is essential for ensuring effective airport operations. This article introduces AbSRiM, a novel agent‐based modeling and simulation approach to perform security risk management for airport operations that uses formal sociotechnical models that include temporal and spatial aspects. The approach contains four main steps: scope selection, agent‐based model definition, risk assessment, and risk mitigation. The approach is based on traditional security risk management methodologies, but uses agent‐based modeling and Monte Carlo simulation at its core. Agent‐based modeling is used to model threat scenarios, and Monte Carlo simulations are then performed with this model to estimate security risks.The use of the AbSRiM approach is demonstrated with an illustrative case study. This case study includes a threat scenario in which an adversary attacks an airport terminal with an improvised explosive device. The approach provides a promising way to include important elements, such as human aspects and spatiotemporal aspects, in the assessment of risk. More research is still needed to better identify the strengths and weaknesses of the AbSRiM approach in different case studies, but results demonstrate the feasibility of the approach and its potential.

18 January 2020 in Aerospace
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Journal Article
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SJStef Janssen
Stef Janssen
DMDiogo Matias
Diogo Matias
Alexei  SharpanskykhAlexei Sharpanskykh
Alexei Sharpanskykh
Airports are attractive targets for terrorists, as they are designed to accommodate and process large amounts of people, resulting in a high concentration of potential victims. A popular method to mitigate the risk of terrorist attacks is through security patrols, but resources are often limited. Game theory is commonly used as a methodology to find optimal patrol routes for security agents such that security risks are minimized. However, game-theoretic models suffer from payoff uncertainty and often rely solely on expert assessment to estimate game payoffs. Experts cannot incorporate all aspects of a terrorist attack in their assessment. For instance, attacker behavior, which contributes to the game payoff rewards, is hard to estimate precisely. To address this shortcoming, we proposed a novel empirical game theory approach in which payoffs are estimated using agent-based modeling. Using this approach, we simulated different attacker and defender strategies in an agent-based model to estimate game-theoretic payoffs, while a security game was used to find optimal security patrols. We performed a case study at a regional airport, and show that the optimal security patrol is non-deterministic and gives special emphasis to high-impact areas, such as the security checkpoint. The found security patrol routes are an improvement over previously found security strategies of the same case study.

3 June 2017 in Lecture Notes in Computer Science
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Book Chapter
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SJStef Janssen
Stef Janssen
ASAlexei Sharpanskykh
Alexei Sharpanskykh

1 January 2022
Verified
Book Chapter
Closed access
PDF file
SJStef Janssen
Stef Janssen
Alexei  SharpanskykhAlexei Sharpanskykh
Alexei Sharpanskykh
Seyed Sahand Mohammadi ZiabariSeyed Sahand Mohammadi Ziabari
Seyed Sahand Mohammadi Ziabari