To assure the opacity, an optimal problem is to retain the occurring events sequences as many as possible. Contrary to such problem, the other optimal problem is to preserve the minimal occurring events sequences. In the paper, based on the choosing cost, an optimal opacity-enforcing model is presented to minimize the sum of discount choosing cost, which is not only to preserve the opacity, but also to retain the secret to the maximum. To solve the model, two scenarios on opacity are considered. For the two scenarios, some algorithms are presented to achieve the optimal solution for the model by using the method of dynamic programming. And then, the solutions produced by the algorithms are proved correctly by theoretical proof. Finally, some illustrations for the algorithms are given.

During the Covid-19 pandemic, although the experience of workers and managers was examined, the role, experiences and functions of supervisors was relatively underexplored, with no investigation into their changing health and safety responsibilities. This project attempted to fill this gap. Twenty supervisors across Canada were interviewed for an hour. A Framework Method guided the study. We used a conceptual framework of 10 supervisor functions to help direct the data collection, identify codes, manage and organize the data analysis, and identify major themes which were highlighted in the findings. What was found was that since supervisors did not have access to workers’ homes, they could not execute most of their OHS functions. They were obliged to give workers more control over how and when they worked. They Increased their communications with their workers in response to workers’ psychological health concerns. Notably, supervisors reported that they were under extreme stress. A hybrid work environment, with workers sometimes working at home, has become the new norm. Supervisor stress will continue to escalate unless upper management provides more support, supervisors get training on how to deal with the psychological health and safety of workers, and supervisors’ responsibilities are re-defined for at-home workers.