Extended security control and delay propagation in air cargo transport operations: implications for supply chain continuity
DOI: https://doi.org/10.3846/transport.2025.25801Abstract
Prior research on security controls in air cargo terminals has primarily focused on protecting passengers, crews, and airport infrastructure, while largely overlooking the maintenance of supply chain continuity. The present study addresses this gap by analysing how the configuration, spatial placement, and scheduling of screening procedures affect the stability of cargo flows, as well as the incidence and propagation of delays in air freight operations. Evidence was collected at 2 terminals – a regional facility in southern Poland and a large international terminal in southern Europe, which enabled a comparative assessment that accounts for organisational and structural differences. The analysis mapped screening procedures onto the operational timeline of cargo-handling. Standard screening consisted of radiographic inspection of palletised consignments using an X-ray system. A negative result triggered an extended screening path comprising, in sequence, canine inspection, chemical screening using reactive swabs, and manual inspection of the load unit after opening by a qualified specialist. The total delay was computed as the sum of the times associated with the additional screening steps and the waiting time for the substitute uplift. Findings for 2022–2024 indicate pronounced differences between terminals in both the scale and effectiveness of controls. At the regional terminal, 3…6% of shipments were routed to extended screening, the average duration of additional actions was 1…2 h, and the final delay was 14…20 h. At the international terminal, the corresponding values were 12…15%, 5…7 h, and 84…95 h. The most significant delays were generated by procedures requiring external specialists, such as crate-opening technicians, and by the organisation of replacement transport. Where specialist support was provided periodically, the waiting time for inspection could reach up to 7 days, whereas smaller facilities operated with near-immediate response times. Based on these results, several operational improvements are indicated. Recommended actions include maintaining specialists on-call, issuing immediate notifications of adverse X-ray outcomes to planning teams, and selectively automating repetitive steps. Implementing these measures is expected to reduce inspection-related delays, improve on-time delivery performance, and enhance the resilience of air cargo supply chains.
First published online 23 January 2026
Keywords:
air cargo transport, security screening, extended checks, delay propagation, supply chain continuity, terminal operations, schedulingHow to Cite
Share
License
Copyright (c) 2025 The Author(s). Published by Vilnius Gediminas Technical University.
This work is licensed under a Creative Commons Attribution 4.0 International License.
References
Adenigbo, A. J.; Mageto, J.; Luke, R. 2023. Adopting technological innovations in the air cargo logistics industry in South Africa, Logistics 7(4): 84. https://doi.org/10.3390/logistics7040084
Amaruchkul, K. 2019. Optimal air-cargo allotment contract with multiple freight forwarders, Communications in Computer and Information Science 966: 177–197. https://doi.org/10.1007/978-3-030-16035-7_10
Baxter, G. 2022. An assessment of waste management at a major European based air cargo terminal operator: a case study of Frankfurt cargo services, International Journal of Environment, Agriculture and Biotechnology 7(5): 166–180. https://doi.org/10.22161/ijeab.75.17
Bierwirth, B.; Brylka, R.; Schwanecke, U. 2021. Business process transformation in air cargo logistics, in E. De La Poza, S. E. Barykin (Eds). Global Challenges of Digital Transformation of Markets, 77–92.
Bombelli, A.; Fazi, S. 2022. The ground handler dock capacitated pickup and delivery problem with time windows: a collaborative framework for air cargo operations, Transportation Research Part E: Logistics and Transportation Review 159: 102603. https://doi.org/10.1016/j.tre.2022.102603
Boonekamp, T.; Burghouwt, G. 2017. Measuring connectivity in the air freight industry, Journal of Air Transport Management 61: 81–94. https://doi.org/10.1016/j.jairtraman.2016.05.003
Brandt, F.; Nickel, S. 2019. The air cargo load planning problem – a consolidated problem definition and literature review on related problems, European Journal of Operational Research 275(2): 399–410. https://doi.org/10.1016/j.ejor.2018.07.013
Chen, J. 2024. Modeling and simulation analysis of optimal layout scheme of aviation logistics park based on genetic algorithm, Advanced Control for Applications 6(4): e200. https://doi.org/10.1002/adc2.200
Cheng, P.; Gu, C.; Zhang, Y.; Chen, Y.; Bi, J. 2024. Optimization strategy for storage location allocation in air cargo warehouse area, E3S Web of Conferences 512: 03011. https://doi.org/10.1051/e3sconf/202451203011
Chu, X.; Wang, Y.; Lin, Y. H.; Chew, E. P. 2024. Offshore consolidation centre for air cargo operations: model and solution methods, OR Spectrum 46: 1295–1327. https://doi.org/10.1007/s00291-024-00764-0
Cordova, A. 2022. Technologies for primary screening in aviation security, Journal of Transportation Security 15: 141–159. https://doi.org/10.1007/s12198-022-00248-8
Delgado, F.; Mora, J. 2021. A matheuristic approach to the air-cargo recovery problem under demand disruption, Journal of Air Transport Management 90: 101939. https://doi.org/10.1016/j.jairtraman.2020.101939
Delgado, F.; Sirhan, C.; Katscher, M.; Larrain, H. 2020. Recovering from demand disruptions on an air cargo network, Journal of Air Transport Management 85: 101799. https://doi.org/10.1016/j.jairtraman.2020.101799
Desai, J.; Srivathsan, S.; Lai, W. Y.; Li, L.; Yu, C. 2023. An optimization-based decision support tool for air cargo loading, Computers & Industrial Engineering 175: 108816. https://doi.org/10.1016/j.cie.2022.108816
Diefenbach, H.; Erlemann, N.; Lunin, A.; Grosse, E. H.; Schocke, K.-O.; Glock, C. H. 2023. Improving processes and ergonomics at air freight handling agents: a case study, International Journal of Logistics Research and Applications: a Leading Journal of Supply Chain Management 26(4): 399–420. https://doi.org/10.1080/13675567.2021.1958305
Domingues, S.; Macário, R.; Pauwels, T.; Van de Voorde, E.; Vanelslander, T.; Vieira, J. 2014. An assessment of the regulation of air cargo security in Europe: a Belgian case study, Journal of Air Transport Management 34: 131–139. https://doi.org/10.1016/j.jairtraman.2013.10.001
Farid, F.; Donyatalab, Y. 2022. Sustainable supply chain of aviation fuel based on analytical hierarchy process (AHP) under uncertainty of q-ROFSs, Lecture Notes in Networks and Systems 308: 578–588. https://doi.org/10.1007/978-3-030-85577-2_68
Feng, B.; Jiang, Z.; Lai, F. 2020. Robust approach for air cargo freight forwarder selection under disruption, Annals of Operations Research 291(1–2): 339–360. https://doi.org/10.1007/s10479-019-03330-y
Feng, B.; Li, Y.; Shen, Z.-J. M. 2015. Air cargo operations: literature review and comparison with practices, Transportation Research Part C: Emerging Technologies 56: 263–280. https://doi.org/10.1016/j.trc.2015.03.028
Florido-Benítez, L. 2023. The Role of the Top 50 US cargo airports and 25 air cargo airlines in the logistics of e-commerce companies, Logistics 7(1): 8. https://doi.org/10.3390/logistics7010008
Gerardo Muros Anguita, J.; Díaz-Olariaga, O. 2023. Air cargo transport demand forecasting using ConvLSTM2D, an artificial neural network architecture approach, Case Studies on Transport Policy 12: 101009. https://doi.org/10.1016/j.cstp.2023.101009
Hassam, S. F.; Zainal, N. N.; Akbar, J.; Shaharudin, M. R.; Kamalrudin, N. A. 2018. Factors that lead to the supply chain safety compliance in air cargo industry, International Journal of Supply Chain Management 7(6): 254–266. Available from Internet: https://ojs.excelingtech.co.uk/index.php/IJSCM/article/view/2674
He, H.; Wu, H.; Tsui, K. W. H.; Wang, B.; Fu, X. 2024. Spatiotemporal evolution of air cargo networks and its impact on economic development – an analysis of China′s domestic market before and during the COVID-19 pandemic, Journal of Transport Geography 117: 103872. https://doi.org/10.1016/j.jtrangeo.2024.103872
Huang, K.; Lu, H. 2015. A linear programming-based method for the network revenue management problem of air cargo, Transportation Research Procedia 7: 459–473. https://doi.org/10.1016/j.trpro.2015.06.024
Huang, L.; Xiao, F.; Zhou, J.; Duan, Z.; Zhang, H.; Liang, Z. 2023. A machine learning based column-and-row generation approach for integrated air cargo recovery problem, Transportation Research Part B: Methodological 178: 102846. https://doi.org/10.1016/j.trb.2023.102846
İlgün, D.; Alptekin, S. E. 2022. A capacity allocation model for air cargo industry: a case study, Lecture Notes in Networks and Systems 505: 426–437. https://doi.org/10.1007/978-3-031-09176-6_49
Janić, M. 2019. Modeling the resilience of an airline cargo transport network affected by a large scale disruptive event, Transportation Research Part D: Transport and Environment 77: 425–448. https://doi.org/10.1016/j.trd.2019.02.011
Kaeothep, W.; Nonsiri, S. 2022. Optimization of ULD load planning using MILP: mixed integer linear programming, in 2022 7th International Conference on Business and Industrial Research (ICBIR), 19–20 May 2022, Bangkok, Thailand, 155–160. https://doi.org/10.1109/icbir54589.2022.9786518
Kaščeev, A.; Endrizalová, E.; Vittek, P. 2022. Air cargo demand prediction on selected Routes by Holt–Winter algorithm, in 2022 New Trends in Civil Aviation (NTCA), 26–27 October 2022, Prague, Czech Republic, 87–91. https://doi.org/10.23919/ntca55899.2022.9934392
Kierzkowski, A.; Kisiel, T. 2015. Simulation model of logistic support for functioning of ground handling agent, taking into account a random time of aircrafts arrival, in International Conference on Military Technologies (ICMT) 2015, 19–21 May 2015, Brno, Czech Republic, 1–6. https://doi.org/10.1109/miltechs.2015.7153694
Kierzkowski, A.; Kisiel, T.; Uchroński, P.; Vidović, A. 2023. Simulation model for sustainable management of the air cargo screening process, Energies 16(21): 7246. https://doi.org/10.3390/en16217246
Kim, H. K.; Lee, C. W. 2019. Development of a cost forecasting model for air cargo service delay due to low visibility, Sustainability 11(16): 4390. https://doi.org/10.3390/su11164390
Kulak, O.; Genç, A.; Taner, M. E. 2018. A decision making tool considering risk assessment of sub-contracting agents for an air cargo shipment planning problem, Journal of Air Transport Management 69: 123–136. https://doi.org/10.1016/j.jairtraman.2018.02.005
Kushwaha, D. K.; Sen, G. 2023. Multi-trip pickup and delivery problem in one to many and many to one (I-M/M-I) transportation network, in 2023 IEEE International Conference on Industrial Engineering and Engineering Management (IEEM), 18–21 December 2023, Singapore, 1588–1592. https://doi.org/10.1109/ieem58616.2023.10406505
Latscha, M.; Schwaninger, A.; Sauer, J.; Sterchi, Y. 2024. Performance of X-ray baggage screeners in different work environments: comparing remote and local cabin baggage screening, International Journal of Industrial Ergonomics 102: 103598. https://doi.org/10.1016/j.ergon.2024.103598
Lau, C. W.; Liu, J.; Ma, X. 2024. Blockchain-based messaging and information sharing systems for air cargo supply chains, IEEE Transactions on Engineering Management 71: 9019–9034. https://doi.org/10.1109/tem.2023.3314733
Le, W. 2018. Application of wireless sensor network and RFID monitoring system in airport logistics, iJOE: International Journal of Online and Biomedical Engineering (iJOE) 14(1): 89–103. https://doi.org/10.3991/ijoe.v14i01.8058
Lee, C. K. M.; Zhang, S.; Ng, K. K. H. 2019. Design of an integration model for air cargo transportation network design and flight route selection, Sustainability 11(19): 5197. https://doi.org/10.3390/su11195197
Lee, J.; Park, J.; Park, J. Y.; Chae, M.; Mun, J.; Jung, J. H. 2023. Material discrimination using X-Ray and neutron, Journal of Radiation Protection and Research 48(4): 167–174. https://doi.org/10.14407/jrpr.2023.00080
Lee, N.-S.; Mazur, P. G.; Bittner, M.; Schoder, D. 2021. An intelligent decision-support system for air cargo palletizing, in Proceedings of the 54th Hawaii International Conference on System Sciences, 4–9 January 2021, Hawaii, HI, US, 1405–1414. https://doi.org/10.24251/hicss.2021.170
Li, C.; Mao, J.; Li, L.; Wu, J.; Zhang, L.; Zhu, J.; Pan, Z. 2024. Flight delay propagation modeling: data, methods, and future opportunities, Transportation Research Part E: Logistics and Transportation Review 185: 103525. https://doi.org/10.1016/j.tre.2024.103525
Li, H.; Bai, J.; Cui, X.; Li, Y, Sun, S. 2020. A new secondary decomposition-ensemble approach with Cuckoo search optimization for air cargo forecasting, Applied Soft Computing 90: 106161. https://doi.org/10.1016/j.asoc.2020.106161
Li, T. 2020. A SWOT analysis of China′s air cargo sector in the context of COVID-19 pandemic, Journal of Air Transport Management 88: 101875. https://doi.org/10.1016/j.jairtraman.2020.101875
Liu, Y.; Yin, M.; Hansen, M. 2019. Economic costs of air cargo flight delays related to late package deliveries, Transportation Research Part E: Logistics and Transportation Review 125: 388–401. https://doi.org/10.1016/j.tre.2019.03.017
Lu, H.-A.; Chung, C.-S. 2023. Loading operation efficiency for international air express at a spoke airport, Aviation 27(3): 162–176. https://doi.org/10.3846/aviation.2023.19976
Lu, Y.; Dong, C.; Nan, M.; Chen, X.; Wei, Y. 2023. Optimal method of air cargo loading under multi-constraint conditions, Lecture Notes in Electrical Engineering 996: 300–308. https://doi.org/10.1007/978-981-19-9968-0_36
Ma, H.-L.; Sun, Y.; Chung, S.-H.; Chan, H. K. 2022. Tackling uncertainties in aircraft maintenance routing: a review of emerging technologies, Transportation Research Part E: Logistics and Transportation Review 164: 102805. https://doi.org/10.1016/j.tre.2022.102805
Ma, H.-L.; Sun, Y.; Mo, D. Y.; Wang, Y. 2025. Impact of passenger unused baggage capacity on air cargo delivery, Annals of Operations Research 348(2): 1069–1085. https://doi.org/10.1007/s10479-023-05248-y
Mesquita, A. C. P.; Sanches, C. A. A. 2024. Air cargo load and route planning in pickup and delivery operations, Expert Systems with Applications 249: 123711. https://doi.org/10.1016/j.eswa.2024.123711
Milambo, D.; Phiri, J. 2019. Aircraft spares supply chain management for the aviation industry in Zambia based on the supply chain operations reference (SCOR) model, Open Journal of Business and Management 7(3): 1183–1195. https://doi.org/10.4236/ojbm.2019.73083
Molchanova, K. 2021. Organization of aviation enterprises′ interaction based on the digital platform, Virtual Economics 4(1): 77–97. https://doi.org/10.34021/ve.2021.04.01(4)
Nazeer, S.; Saleem, H. M. N.; Shafiq, M. 2024. Examining the influence of adoptability, alignment, and agility approaches on the sustainable performance of aviation industry: an empirical investigation of supply chain perspective, International Journal of Aviation, Aeronautics, and Aerospace 11(1). https://doi.org/10.58940/2374-6793.1898
Niu, B.; Dai, Z.; Zhuo, X. 2019. Co-opetition effect of promised-delivery-time sensitive demand on air cargo carriers′ big data investment and demand signal sharing decisions, Transportation Research Part E: Logistics and Transportation Review 123: 29–44. https://doi.org/10.1016/j.tre.2019.01.011
Nobert, Y.; Roy, J. 1998. Freight handling personnel scheduling at air cargo terminals, Transportation Science 32(3): 295–301. https://doi.org/10.1287/trsc.32.3.295
Park, A.; Lee, M. K.; Park, H.; Choi, J.-H.; Song, J. M. 2023. The impact of security oversight on air cargo price and demand, Journal of Transportation Security 16: 2. https://doi.org/10.1007/s12198-023-00259-z
Pyza, D.; Golda, P. 2011. Transport cargo handling shipments in air transport in the aspect of supply chains, in 2011 21st International Conference on Systems Engineering, 16–18 August 2011, Las Vegas, NV, US, 442–445. https://doi.org/10.1109/icseng.2011.87
Rabten, W.; Hasachoo, N.; Sirisawat, P.; Yoo, K. E. 2021. A fuzzy analytic hierarchy process approach to identify the relative importance of factors influencing air cargo operation: a case study with Paro international airport in Bhutan, in 11th Annual International Conference on Industrial Engineering and Operations Management, 7–11 March 2021, Singapore. https://doi.org/10.46254/an11.20210404
Rodbundith, T. S.; Sirisawat, P.; Hasachoo, N. 2021. E-commerce: challenges that lies ahead of the future air cargo operation, in 2021 IEEE International Conference on Industrial Engineering and Engineering Management (IEEM), 13–16 December 2021, Singapore, 134–137. https://doi.org/10.1109/ieem50564.2021.9672885
Romero-Silva, R.; Mujica Mota, M. 2022. Trade-offs in the landside operations of air cargo hubs: horizontal cooperation and shipment consolidation policies considering capacitated nodes, Journal of Air Transport Management 103: 102253. https://doi.org/10.1016/j.jairtraman.2022.102253
Rountree, C. D.; Demetsky, M. J. 2006. Framework for analysis of security measures within on-airport cargo facilities, Transportation Research Record: Journal of the Transportation Research Board 1942: 31–38. https://doi.org/10.1177/0361198106194200105
Ryczyński, J.; Kierzkowski, A. 2023. The impact of the level of training of airport security control operators on the energy consumption of the baggage control process, Energies 16(19): 6957. https://doi.org/10.3390/en16196957
Ryczyński, J.; Kierzkowski, A.; Jodejko-Pietruczuk, A. 2024. Air cargo handling system assessment model: a hybrid approach based on reliability theory and fuzzy logic, Sustainability 16(23): 10469. https://doi.org/10.3390/su162310469
Sahoo, R.; Bhowmick, B.; Tiwari, M. K. 2023. Developing a model to optimise the cost of consolidated air freight considering the varying scenarios, International Journal of Logistics Research and Applications: a Leading Journal of Supply Chain Management 26(8): 1035–1059. https://doi.org/10.1080/13675567.2021.2010682
Sekhar, V. V. P.; Deepthi, P. P.; Rameshan, R. M. 2024. X-ray image denoising for baggage screening using learning based methods, Electronic Imaging 36: IPAS-244. https://doi.org/10.2352/ei.2024.36.10.IPAS-244
Siebers, P.-O.; Sherman, G.; Aickelin, U. 2009. Development of a cargo screening process simulator: a first approach, Social Science Research Network (SSRN) 2009: 2830314. https://doi.org/10.2139/ssrn.2830314
Skorupski, J.; Uchroński, P. 2023. Capacity assessment of the airport cargo screening system under disruptions, WUT Journal of Transportation Engineering 136: 101–122. https://doi.org/10.5604/01.3001.0053.9612
Skorupski, J.; Uchroński, P. 2018. Evaluation of the effectiveness of an airport passenger and baggage security screening system, Journal of Air Transport Management 66: 53–64. https://doi.org/10.1016/j.jairtraman.2017.10.006
Spandonidis, C.; Sedikos, E.; Giannopoulos, F.; Petsa, A.; Theodoropoulos, P.; Chatzis, K.; Galiatsatos, N. 2022. A novel intelligent IoT system for improving the safety and planning of air cargo operations, Signals 3(1): 95–112. https://doi.org/10.3390/signals3010008
Meenakshi Sundaram, B.; Rajalakshmi, B.; Saxena, A.; Vasumati, B.; Akshatha, P. 2024. AirGuard AI: revolutionizing air cargo inspection through Pygame and YOLOv8 simulation, in 2024 11th International Conference on Reliability, Infocom Technologies and Optimization (Trends and Future Directions) (ICRITO), 14–15 March 2024, Noida, India, 1–6. https://doi.org/10.1109/icrito61523.2024.10522203
Suwanwong, T.; Sopadang, A.; Hanaoka, S.; Rodbundith, T. 2018. Evaluation of air cargo connectivity and policy in Thailand, Transport Policy 72: 24–33. https://doi.org/10.1016/j.tranpol.2018.09.005
Tseremoglou, I.; Bombelli, A.; Santos, B. F. 2022. A combined forecasting and packing model for air cargo loading: a risk-averse framework, Transportation Research Part E: Logistics and Transportation Review 158: 102579. https://doi.org/10.1016/j.tre.2021.102579
Tu, J.; Yang, X.; Jiang, Q.; Li, C.; Li, Y. 2023. Research on blockchain-based aviation supply chain management, in ICCSMT′23: Proceedings of the 2023 4th International Conference on Computer Science and Management Technology, 13–15 October 2023, Xi′an China, 102–107. https://doi.org/10.1145/3644523.3644542
Velayudhan, D.; Hassan, T.; Damiani, E.; Werghi, N. 2023. Recent advances in baggage threat detection: a comprehensive and systematic survey, ACM Computing Surveys 55(8): 165. https://doi.org/10.1145/3549932
Wang, N.; Gao, Y.; He, J.-T.; Yang, J. 2022. Robustness evaluation of the air cargo network considering node importance and attack cost, Reliability Engineering & System Safety 217: 108026. https://doi.org/10.1016/j.ress.2021.108026
Wen, X.; Xu, X.; Choi, T.-M.; Chung, S.-H. 2020. Optimal pricing decisions of competing air-cargo-carrier systems – impacts of risk aversion, demand, and cost uncertainties, IEEE Transactions on Systems, Man, and Cybernetics: Systems 50(12): 4933–4947. https://doi.org/10.1109/tsmc.2019.2930725
Wong, E. Y. C.; Mo, D. Y.; So, S. 2021. Closed-loop digital twin system for air cargo load planning operations, International Journal of Computer Integrated Manufacturing 34(7–8): 801–813. https://doi.org/10.1080/0951192X.2020.1775299
Xiao, F.; Guo, S.; Huang, Li.; Huang, Le.; Liang, Z. 2022. Integrated aircraft tail assignment and cargo routing problem with through cargo consideration, Transportation Research Part B: Methodological 162: 328–351. https://doi.org/10.1016/j.trb.2022.06.005
Zapola, G. S.; Silva, E. J.; Alves, C. J. P.; Müller, C. 2024. Towards a resilience assessment framework for the airport passenger terminal operations, Journal of Air Transport Management 114: 102508. https://doi.org/10.1016/j.jairtraman.2023.102508
Zhang, A.; Lang, C.; Hui, Y. V.; Leung, L. 2007. Intermodal alliance and rivalry of transport chains: the air cargo market, Transportation Research Part E: Logistics and Transportation Review 43(3): 234–246. https://doi.org/10.1016/j.tre.2006.10.003
Zhao, X.; Dong, Y.; Zuo, L. 2023. A combinatorial optimization approach for air cargo palletization and aircraft loading, Mathematics 11(13): 2798. https://doi.org/10.3390/math11132798
Zhao, X.; Li, Y.; Wang, Z.; Xu, J.; Li, P. 2024. Cooperative Loading Optimization of Multi-Segment Flights for Medium-Sized Aircraft Based on Loading and Unloading Sequence, Journal of Beijing University of Aeronautics and Astronautics 50(4): 1147–1161. https://doi.org/10.13700/j.bh.1001-5965.2022.0439 (in Chinese).
Zheng, H.; Sun, H.; Zhu, S.; Kang, L.; Wu, J. 2023. Air cargo network planning and scheduling problem with minimum stay time: a matrix-based ALNS heuristic, Transportation Research Part C: Emerging Technologies 156: 104307. https://doi.org/10.1016/j.trc.2023.104307
Zheng, S.; Wang, K.; Jiang, C. 2024. Converting passenger aircraft into cargo planes under volatile market demand, Transportation Research Part A: Policy and Practice 181: 104013. https://doi.org/10.1016/j.tra.2024.104013
Zhou, G.; Li, D.; Bian, J.; Zhang, Y. 2024. Airfreight forwarder′s shipment planning: Shipment consolidation and containerization, Computers & Operations Research 161: 106443. https://doi.org/10.1016/j.cor.2023.106443
Zhu, L.; Wu, Y.; Smith, H.; Luo, J. 2023. Optimisation of containerised air cargo forwarding plans considering a hub consolidation process with cargo loading, Journal of the Operational Research Society 74(3): 777–796. https://doi.org/10.1080/01605682.2022.2096493
View article in other formats
CrossMark check
Published
Issue
Section
Copyright
Copyright (c) 2025 The Author(s). Published by Vilnius Gediminas Technical University.
License
This work is licensed under a Creative Commons Attribution 4.0 International License.