Expert Systems With Applications 54 (2016) 284–293 Contents lists available at ScienceDirect Expert Systems With Applications journal homepage: www.elsevier.com/locate/eswa Managing the process of passenger security control at an airport using the fuzzy inference system Jacek Skorupski a,∗ , Piotr Uchro ´ nski a,b a Warsaw University of Technology, Faculty of Transport, ul. Koszykowa 75, 00-662 Warszawa, Poland b Upper Silesian Aviation Group, al. Korfantego 38, 40-161 Katowice, Poland a r t i c l e i n f o Keywords: Passenger security screening Fuzzy sets and fuzzy inference Civil aviation security Critical infrastructure protection Terrorist threat a b s t r a c t Elements of air transport infrastructure as well as passengers and aircraft are constantly at risk of terrorist attack. One of the most important preventative methods is the security control of persons and baggage at airports. Managing this process requires finding a compromise between high capacity of the terminal and the high effectiveness of the security control. The purpose of this study is to show the applicability of an expert system, which assists security managers in deciding how to organise the security screening process. Due to the important role of the human factor, the need to use expert’s opinions and the high uncertainty and imprecise nature of information, the developed model and computer tool FUPSCA (FUzzy Passenger Security Control Assessment) uses the fuzzy sets theory and a fuzzy inference system. It’s use allows us to adjust the operating parameters of the security screening checkpoint, namely the WTMD sensitivity, number of employees and the frequency of manual controls, to the current level of terrorist threat. As a result of the study it was found that if we want to achieve higher security control effectiveness we should first increase the WTMD’s sensitivity and only then increase the frequency of additional manual controls and not the other way round. Of course the FUPSCA system provides specific, quantitative answers. In the future it will be necessary to manage the operation of the passenger security control system using multi-criteria evaluations of: capacity, effectiveness, passenger comfort. FUPSCA will be able to effectively support this process. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction The transport systems considered parts of critical infrastructure are constantly at risk of terrorist threat. Airport terminals, although reasonably well protected, are a frequent target for attacks. In addi- tion, they are in practice the only locations where it is possible to detect and foil an attempt to bring explosives or weapons onboard an aircraft. In the recent years particularly dramatic attacks took place at air- ports in Burgas and Moscow. The first of the attacks took place in 2012 when a bomb was detonated in a bus at the airport in Burgas in Bul- garia. As a result of the explosion caused by a suicide bomber seven people were killed and 32 persons were injured (Shmulovich & Zion, 2012). The attack took place on the 18th anniversary of a bombing in Buenos Aires, which occurred on the 18th July 1994 and 85 people were killed. The attack at Domodiedowo airport in Moscow occurred in 2011. At least 36 people were killed and at least 180 people were injured (Rosenberg, 2011). ∗ Corresponding author. Tel.: +48 222347339. E-mail addresses: jsk@wt.pw.edu.pl (J. Skorupski), puchronski@gtl.com.pl (P. Uchro ´ nski). An attempt to actively respond to the terrorist threat involves se- curity control performed at airports. The subject of our study is a method for quantitative evaluation of the effectiveness of passenger security control at a security checkpoint (SCP). In practice, a consider- able problem is managing the security checkpoint operation, includ- ing the selection of settings for the devices used to detect prohibited items and the selection of SCP operators. The qualitative relation be- tween the various parameters of system operation and the obtained operation effectiveness is quite obvious. However, the quantitative relation is at this point unknown. The existing few scientific analyses of this question are related mostly to the capacity of SCP, assuming that the security level is appropriate. 1.1. Organisation of passenger security control at an airport The person security control is one of the basic methods of pro- tection against acts of unlawful interference (ICAO, 2010). The safety of departing passengers relies mostly on its effectiveness. It is there- fore very important that the tools used during the security control of persons are adequate to the development of methods employed by terrorists around the world. http://dx.doi.org/10.1016/j.eswa.2015.11.014 0957-4174/© 2015 Elsevier Ltd. All rights reserved.