A fuzzy system for evaluation of baggage screening devices at an airport

Abstract

An airport is a complex engineering system; it is composed of many elements intercon - nected with numerous internal relations with a strongly pronounced role of the human factor. One of the specific tasks carried out by the Airport Managing Entity (AME) is to con fig ure the Airport Security System (ApSS) so that to attain the expected level of confidence in the airport safety and security. This task consists in selection of infrastructure, technical equipment, allocation of personnel and financial means that are necessary to perform all functions of the ApSS. One of the aspects of the con fig uration of the ApSS is the allocation of available x-ray baggage screening devices searching for items prohibited for transportation. To make this allocation, we need to know how effective these devices are (in terms of detecting prohibited items). This assessment is dependent on several factors which are treated as linguis - tic variables and are input to fuzzy inference system: the ability to detect explosives (linguistic variable Detectability), the number of detection lines (linguistic variable Number of detection lines), the effective - ness of the TIP (Threat Image Projection) system (linguistic variable TIP evaluation) and the age of the machine (linguistic variable Device age). Some of these elements are difficult to objective assessment, as they are heavily dependent on the human factor or the information is uncertain and incomplete. So fuzzy ApSS analysis is proposed. The output from the fuzzy inference system is linguistic variable Device evaluation. The meaning of this variable is the ability to protect the aircraft against prohibited items. The proposed new method of assessing the airport baggage screening system involves the construction of a hierarchical fuzzy inference system. Such a system has been built with the use of the compositional fuzzy inference rule. The usefulness of the method is exemplified for Katowice-Pyrzowice international airport, for which an assessment of devices has been performed. The results show that not only allocation of specific devices for specific control points is important for the security of passengers. Also important are the locally accepted principles of their work, which so far are not specified by international regulations. This applies for instance to the selection of the number (frequency) of TIP images. Preliminary analyzes show that the proposed approach can be effective as part of an expert system for supporting the airport operator in con fig uring ApSS.