In underbalanced drilling (UBD), the bottom hole pressure is kept below pore pressure, causing pressure-dependent influx of reservoir gas into wellbore that makes system unstable at low drawdowns. this article, we propose a feedback controller which stabilizes system, represented by “reduced drift flux model (DFM),” around an arbitrary setpoint, while using only topside measurement and assuming...

this paper deals with leader-following and leaderless consensus problems of high-order multi-input/multi-output (mimo) multi-agent systems with unknown nonlinear dynamics in the presence of uncertain external disturbances. the agents may have different dynamics and communicate together under a directed graph. a distributed adaptive method is designed for both cases. the structures of the contro...

Some of the parameters in issues of the reality world are uncertainty. One of the uncertain problems with the qualitative parameters is economic problems such as bankruptcy problem. In this case, there is a probability of dealing with imprecise concepts including the intervals regarding the official’s viewpoint, organizations’ managers. Accordingly, this article uses the concepts of data envelo...

a common problem arising in project management is the fact that the baseline schedule is often disrupted during the project execution because of uncertain parameters. as a result, project managers are often unable to meet the deadline time of the milestones. robust project scheduling is an effective approach in case of uncertainty. upon adopting this approach, schedules are protected against po...