This project studied whether a digital interlocking which had been programmed with ladder logic (Boolean program) would obey generic safety properties. This was carried out by translating the ladder logic into an alternate representation and applying various techniques to allow specification of safety properties. Finally, a proof engine was used to formally verify if these properties were fulfi...

A worker’s job can be improved through on-the-job search (OJS) and job upgrading. Incorporating these external and internal job dynamics into a directed search model, this paper analytically characterizes the socially efficient allocation and quantitatively evaluates the model. The analysis shows that efficient OJS is front-loaded in a worker’s career and stops after a finite number of job swit...

Informed by new measurements of labor market dynamics, I develop and estimate an equilibrium search model of worker mobility. I first describe new facts about the dynamics of wages across involuntary unemployment spells in Denmark. This implies that the job-ladder search model cannot by itself explain all the observed movements of workers between firms. I construct a new model of worker mobilit...

introduction: since human resources in organizations are the most important factors of effectiveness and efficiency, identification of the factors affecting the performance and response of personnel, including intraorganizational changes in management levels is very important. therefore the goal of this research was to determine the effects of organizational changes on employee's reaction of he...

Programmable Logic Controllers are industrial digital computers used as automation controllers in manufacturing processes. The Ladder language is a programming to develop software for such controllers. In this work, we consider the description of expected behaviour program under form timing chart, describing scenario execution. Our aim prove that given conforms temporal by chart. approach amoun...