Design of fuzzy logic based adaptive traffic signal controller

Traffic control of street intersections is one of the most critical elements in providing an efficient flow of traffic in urban networks. Conventionally, pretimed controllers are used, but they cannot respond to real time fluctuations in traffic demand. Traffic actuated signals provide an improvement over pretimed controllers, but their performance deteriorates under heavy traffic conditions. These conditions necessitate the development of a controller that responds to actual traffic demand in real time, with the objective of minimizing vehicle delays, number of stops, etc. Fuzzy logic provides the potential for development of a system that would address these needs; The objective of this research is to design and evaluate a fuzzy logic based controller for traffic intersections that is adaptive to traffic demand. The design uses the standard input traffic flow parameters generated by existing loop detectors. The outcome of this research is a traffic controller that is very responsive to real-time traffic flow for various traffic simulations, including both recurring and non-recurring conditions. Evaluation of the performance of the system is based on minimization of delay and the number of stops. The performance of the fuzzy controller is compared to that of a pretimed controller with the help of traffic packages NETSIM & SOAP-84

A Two-Stage Fuzzy Logic Controller for Traffic Signals

This paper presents the design and evaluation of a fuzzy logic traffic signal controller for an isolated intersection. The controller is designed to be responsive to real-time traffic demands. The fuzzy controller uses vehicle loop detectors, placed upstream of the intersection on each approach, to measure approach flows and estimate queues. These data are used to decide, at regular time intervals, whether to extend or terminate the current signal phase. These decisions are made using a two-stage fuzzy logic procedure. In the first stage, observed approach traffic flows are used to estimate relative traffic intensities in the competing approaches. These traffic intensities are then used in the second stage to determine whether the current signal phase should be extended or terminated. The performance of this controller is compared to that of a traffic-actuated controller for different traffic conditions on a simulated four-approach intersection

Specific packaging and circulation of cytochromes P450, especially 2E1 isozyme, in human plasma exosomes and their implications in cellular communications

Cytochrome P450 (CYP) enzymes metabolize the majority of xenobiotics and are mainly found in hepatic and some extra-hepatic cells. However, their presence and functional role in exosomes, small extracellular vesicles that are secreted from various cells into extracellular fluids including plasma, is unknown. In this study, we analyzed the expression and biological activity of CYP enzymes in human plasma exosomes. First, we optimized isolation of plasma exosomes and characterized them for their physical properties and quality. The results showed that the purity of exosomes (\u3c200 nm) improved upon prior filtration of plasma using a 0.22 micron filter. We then analyzed the relative level of exosomal CYP mRNAs, proteins, and enzyme activity. The results showed that the relative level of CYP enzymes in exosomes is higher than in plasma, suggesting their specific packaging in exosomes. Of the seven CYP enzymes tested, the mRNA of CYP1B1, CYP2A6, CYP2E1, and CYP3A4 were detectable in exosomes. Interestingly, the relative level of CYP2E1 mRNA was \u3e500-fold higher than the other CYPs. The results from the Western blot showed detectable levels of CYP1A1, CYP1B1, CYP2A6, CYP2E1, and CYP3A4. Our results also demonstrated that exosomal CYP2E1 and CYP3A4 show appreciable activity relative to their respective positive controls (CYP-induced baculosomes). Our results also showed that CYP2E1 is expressed relatively higher in plasma exosomes than hepatic and monocytic cells and exosomes derived from these cells. In conclusion, this is the first evidence of the specific packaging and circulation of CYP enzymes, especially CYP2E1, in human plasma exosomes. The findings have biological and clinical significance in terms of their implications in cellular communications and potential use of plasma exosomal CYPs as biomarkers