The paper presents the possibilities of simulation of steady and dynamic regimes for ammonia synthesis columns. We present the possibilities of study of the dynamic regimes for automatic control of the temperature in catalyst layers and propose an advanced control structure using the fresh gas flows between catalyst layers as commands. We also present the possibilities of optimization of the co...

In this paper, a practical method that can be employed to manage security policies using the eXtensible Markup Language (XML) is presented. The method efficiently administrates security policies based on the object oriented role-based access control model (ORBAC). Moreover, an information flow analysis technique is introduced for checking whether or not a created XML-based ORBAC security policy...

Optical flow research has made significant progress in recent years and it can now be computed efficiently and accurately for many images. However, complex motions, large displacements, and difficult imaging conditions are still problematic. In this paper, we present a framework for estimating optical flow which leads to improvements on these difficult cases by 1) estimating occlusions and 2) u...

In this paper we present a simplified tracking method to efficiently track people from a crowd video using the Minimum Mean Square Error (MMSE) technique. The system tracks people from a video sequence and is robust to varied lighting conditions and complex crowded scenes. The method effectively handles small occlusions and invokes a manual tracking procedure under severe occlusions. The system...

This paper studies the dynamics of the traveler’s day-to-day route adjustment process in the general transportation network with fixed or elastic demand and homogeneous or heterogeneous users. Each traveler is assumed to adjust his/her route choice according to the excess travel cost between the instantaneous experienced travel cost and a certain referred level, which induces an aggregate path ...

Flow cover inequalities are among the most effective valid inequalities for capacitated fixed-charge network flow problems. These valid inequalities are based on implications for the flow quantity on the cut arcs of a two-partitioning of the network, depending on whether some of the cut arcs are open or closed. As the implications are only on the cut arcs, flow cover inequalities can be obtaine...

We study a single-product periodic-review inventory system with multiple types of returns. The serviceable products used to fulfill stochastic customer demand can be either manufactured/ordered, or remanufactured from the returned products, and the objective is to minimize the expected total discounted cost over a finite planning horizon. We show that, under some circumstances but not all, the ...

The increasing versatility in order characteristics calls for planning and control systems that are able to evolve in time. Traditional hierarchical systems are usually based on a function-oriented static control structure in which all orders and products are handled similarly. Due to the dynamically changing characteristics of manufacturing environments these static control structures are not ...