ABSTRACT
The City of Zagreb in Croatia and its surroundings have experienced two strong earthquakes within nine months of 2020. Putting this in the context of the increased workload of healthcare facilities due to Covid-19, the distribution system operator (DSO) is encouraged to look for unconventional solutions such as integrating the battery energy storage system (BESS) to supply healthcare facilities during network fault conditions or other extreme network events. The BESS size and location are determined by optimization model, while the control system of the BESS converter, based on the virtual synchronous machine (VSM) concept, is define to test BESS ability to supply critical consumers in the off-grid mode. The models are tested and verified on several real world situations in Zagreb MV distribution network. Future developments and scenarios are also simulated to verify the robustness of the proposed investment. © 2022 IEEE.
ABSTRACT
In this work we present a fully stochastic model of performance analysis of single- and multi-carrier modulations (SCM and MCM) in communication systems affected by impulsive noise. The key performance parameter of the model is the symbol error rate (SER), which is fully determined as a function of the system parameters, including the frame length, symbol power, white noise power, impulsive noise power, and the probability of the impulse events. We derive closed-form analytical expressions for the systems and compare them with simulation results, showing very good agreement for all the impulsive noise scenarios. Specifically, we show under which conditions a MCM system performs better than a SCM system, and vice versa, which can be used to apply an optimal control policy that minimizes SER. The developed model for SCM and MCM systems is conceptually applied to the Covid-19 phenomenology, and consequently the results obtained for SCM and MCM scenarios, are interpreted as decision and management of social distancing (lock/roam) policies. Specifically, we also show under which conditions the "roam" strategy performs better than the "lock" strategy, and vice versa, which can be used to develop an optimal control policy that minimizes the mortality rate (MR). However, the proposed analytical model for the Covid-19 scenario, obtained assuming the similarity with the SCM/MCM systems, could not be tested in full due to the lack of relevant data. Therefore, any management decision cannot be based (only) on the presented model adapted to Covid-19, and necessarily requests the integration of experts opinions. Author
ABSTRACT
OBJECTIVES: To investigate the changes in personal attitudes and behaviour before and after negative serological test results for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. STUDY DESIGN: Cross-sectional questionnaire survey. METHODS: A survey questionnaire was conducted with 200 industry workers (68% males and 32% females) who had previously tested negative for SARS-CoV-2 antibodies. The survey examined participants' self-reported general attitudes towards coronavirus disease 2019 (COVID-19), their sense of fear, as well as their behaviour towards protective measures before and after the testing. RESULTS: Participants perceived the disease as a severe health threat and acknowledged that the protective measures were appropriate. Respondents reported a high level of adherence to measures and low level of fear, both before and after the testing. Although these indicators were statistically significantly reduced after the test (P < 0.004), they did not result in irresponsible non-adherence behaviours. Almost all respondents attributed their application of personal protection measures to factors other than the results of serological screening. CONCLUSIONS: Serological tests do not contribute to irresponsible non-adherence behaviours in an environment where protective measures are efficient. However, they may help reduce fear within society and working environments.