Stability of traffic flow behavior with distributed delays modeling the memory effects of the drivers

Rifat Sipahi — Fri, 18 Dec 2009 12:07:34 PST

Stability analysis of a single-lane microscopic car-following model is studied analytically from the perspective of delayed reactions of human drivers. In the literature, the delayed reactions of the drivers are modeled with discrete delays, which assume that drivers make their control decisions based on the stimuli they receive from a point of time in the history. We improve this model by introducing a distribution of delays, which assumes that the control actions are based on information distributed over an interval of time in history. Such an assumption is more realistic, as it takes into consideration the memory capabilities of the...

Transportation delays in supply networks: stability analysis & system design

Rifat Sipahi — Fri, 18 Dec 2009 12:07:34 PST

Stability of a linear time invariant dynamics with 3 independent delays

Rifat Sipahi — Fri, 18 Dec 2009 12:07:34 PST

Minimization of costs in interconnected supply networks with transportation and decision-making delays

Ilker I. Delice — Fri, 18 Dec 2009 12:07:33 PST

Stability analysis of a high dimensional supply network with 5 delays

Rifat Sipahi — Fri, 18 Dec 2009 12:07:33 PST

Stability analysis of a LTI-TDS dynamics with four (4) independent delays

Rifat Sipahi — Fri, 18 Dec 2009 12:07:33 PST

Delay modeling in supply network dynamics: performance, synchronization, stability

Rifat Sipahi — Fri, 18 Dec 2009 12:07:32 PST

Recent research results in Industrial Engineering and Business disciplines specifically emphasize the critical role of delays in the functionality of supply networks. Delays are inevitable and pervasive; they arise due to the time needed for material deliveries, information flow and human perception towards adjusting to new decisions. Delays are endangering as they contaminate decision-making which ultimately leads to poor performance, synchronization problems and fluctuating inventory levels resulting in major economical losses. It is critical to state that inventory regulation and synchronization in supply networks even without delays is an open problem today due to large scale of the network, nonlinearities,...

First order approximation of the stability regions of time delay systems

Rifat Sipahi — Fri, 18 Dec 2009 12:07:32 PST

An efficient numerical approach for the stability analysis of a class of LTI systems with arbitrary number of delays

Rifat Sipahi — Fri, 18 Dec 2009 12:07:32 PST

Abstract: A practical and numerically efficient algorithm is presented for determining the stability robustness map of a general class of higher order linear time invariant (LTI) systems in the parametric space of arbitrary number of independent delays. The stability of this class of dynamics is of particular interest in low-gain design and multi-agent control problems. The backbone of the new algorithm is inspired by a scaled frequency sweeping technique which enables the exhaustive determination of stability switching hypersurfaces in the parametric space of delays, without requiring nested loops. Two case studies are presented in order to demonstrate the strength of...

An alternative characterization of robust stability and stability radius for linear time delay systems

Bahram Shafai — Fri, 18 Dec 2009 12:07:31 PST