Traceability has become a critical element in supply chain management, particularly in safety-sensitive sectors like food, pharmaceuticals, etc. Upstream (manufacturers, producers, etc.) and downstream (distributors, wholesalers, etc.) supply chain members need to store and handle traceability-related information for providing proof of regulatory compliance to both state authorities and more demanding customers. Consumers also place high expectations on food supply chains (FSC) with specific emphasis on facets related to safety. However, the complexity of modern FSC networks and their fragmentation act as barriers for the development of sound traceability mechanisms. In this paper a distributed trustless and secure architecture for FSC traceability is developed and tested. For assessing the feasibility of the proposed approach, a food traceability case study from a dairy company is presented. The applicability of the model is further illustrated by the development of fully functional smart contracts and a local private blockchain. Moreover, the various links between the proposed blockchain-based model and its managerial implications are presented. The overall benefits of the proposed model are discussed along with fruitful areas for future research. The results are of significant value to both practitioners and researchers.

Green Public Procurement (GPP) is an essential strategy for achieving goals related to public environmental policy, including sustainable production and consumption, streamlined use of resources and mitigation of climate change. The European Union has adopted policies towards “greening” public procurement for member states in order to promote environmental sustainability. Life Cycle Costing (LCC) is a method that measures the financial impact of an investment over the life cycle of a product. The current EU Procurement Directives (2014) are designed to position LCC centrally to sustainable sourcing. Although the literature identifies the links between the environmental dimension through GPP and the economic dimension through the use of LCC, the interaction between them in the context of public procurement has not been adequately captured. The aim of this paper is to evaluate the results of the LCC tools implementation in the context of GPP in Greece and study the economic impact of green procurement in public organizations. The urgent need of reducing energy consumption in the public sector due to the continuing energy crisis and climate change is an additional incentive to evaluate this impact. LCC tools developed by the EU were used, fed with data from public procurement contracts carried out in the Greek public sector. The results show that the adoption of environmental criteria requires market research, planning and coordination to make it cost-effective, especially under the legislative mandate of GPP in Greece by 2022.

From 7 November 2020, Greece adopted a second nationwide lockdown policy to mitigate the transmission of SARS-CoV-2 (the first took place from 23 March to 4 May 2020), just as the second wave of COVID-19 was advancing, as did other European countries. To secure the full benefits of mass vaccination, which started in early January 2021, it is of utmost importance to complement it with mid-term non-pharmaceutical interventions (NPIs). The objective was to minimize human losses and to limit social and economic costs. In this paper a two-phase stochastic dynamic network compartmental model (a pre-vaccination SEIR until 15 February 2021 and a post-vaccination SVEIR from 15 February 2021 to 30 June 2021) is developed. Three scenarios are assessed for the first phase: (a) A baseline scenario, which lifts the national lockdown and all NPIs in January 2021; (b) a “semi-lockdown” scenario with school opening, partial retail sector operation, universal mask wearing, and social distancing/teleworking in January 2021; and (c) a “rolling lockdown” scenario combining a partial lifting of measures in January 2021 followed by a third nationwide lockdown in February 2021. In the second phase three scenarios with different vaccination rates are assessed. Publicly available data along with some first results of the SHARE COVID-19 survey conducted in Greece are used as input. The results regarding the first phase indicate that the “semi-lockdown” scenario clearly outperforms the third lockdown scenario (5.7% less expected fatalities); the second phase is extremely sensitive on the availability of sufficient vaccine supplies and high vaccination rates.

The aviation industry in the COVID-19 pandemic era (caused by the SARS-CoV-2 pathogen) is practically starting from scratch as significant losses have been recorded since the outbreak in December 2019. This paper focuses on the study of the available historical operational data (provisional and final) of international passenger traffic to and from the Hellenic airports. The data originated from the official state statistics agency (Hellenic Civil Aviation Authority, HCAA). A forecasting model was developed to provide an estimation of the international passenger traffic at the Hellenic airports from August to December 2021. Through this analysis, the severe impact of two lockdown events and how they will affect the expected recovery rate of air travel is demonstrated. From this perspective, some first conclusions can be drawn about the expected recovery of international air travel to the growth rates of the 2019 pre-pandemic levels.