Parking guidance and information (PGI) systems are becoming important parts of intelligent transportation systems due to the fact that cars and infrastructure are becoming more and more connected. ...One major challenge in developing efficient PGI systems is the uncertain nature of parking availability in parking facilities (both on-street and off-street). A reliable PGI system should have the capability of predicting the availability of parking at the arrival time with reliable accuracy. In this paper, we study the nature of the parking availability data in a big city and propose a multivariate autoregressive model that takes into account both temporal and spatial correlations of parking availability. The model is used to predict parking availability with high accuracy. The prediction errors are used to recommend the parking location with the highest probability of having at least one parking spot available at the estimated arrival time. The results are demonstrated using real-time parking data in the areas of San Francisco and Los Angeles.
Obtaining accurate information about current and near-term future traffic flows of all links in a traffic network has a wide range of applications, including traffic forecasting, vehicle navigation ...devices, vehicle routing, and congestion management. A major problem in getting traffic flow information in real time is that the vast majority of links is not equipped with traffic sensors. Another problem is that factors affecting traffic flows, such as accidents, public events, and road closures, are often unforeseen, suggesting that traffic flow forecasting is a challenging task. In this paper, we first use a dynamic traffic simulator to generate flows in all links using available traffic information, estimated demand, and historical traffic data available from links equipped with sensors. We implement an optimization methodology to adjust the origin-to-destination matrices driving the simulator. We then use the real-time and estimated traffic data to predict the traffic flows on each link up to 30 min ahead. The prediction algorithm is based on an autoregressive model that adapts itself to unpredictable events. As a case study, we predict the flows of a traffic network in San Francisco, CA, USA, using a macroscopic traffic flow simulator. We use Monte Carlo simulations to evaluate our methodology. Our simulations demonstrate the accuracy of the proposed approach. The traffic flow prediction errors vary from an average of 2% for 5-min prediction windows to 12% for 30-min windows even in the presence of unpredictable events.
The control of underactuated Euler-Lagrange systems with uncertain and switched parameters is an important problem whose solution has many applications. The problem is challenging as standard ...adaptive control techniques do not extend to this class of systems due to structural constraints that lead to parameterization difficulties. This note proposes an adaptive switched control framework that handles the uncertainty and switched dynamics without imposing structural constraints. A case study inspired by autonomous vessel operations is used to show the effectiveness of the proposed approach.
Infective Endocarditis (IE) is a disease that carries high morbidity and mortality risks and involves the infection of the endocardium, and more commonly of the cardiac valves and prosthetic ...material, like implantable defibrillators or pacemakers ....
is a member of the Enterobacteriaceae, first described in 1982 and reclassified as a distinct species in the
genus after identifying biochemical and genomic differences from
It is a rare cause of ...human infections and is supposed to be a co-infector rather than an autonomous cause of infection. The aim of this systematic review was to record and evaluate all available evidence regarding human infections by
. A systematic review of PubMed (through 21 December 2018) for studies providing epidemiological, clinical, and microbiological information, as well as treatment data and outcomes of
infections was performed. A total of 16 studies, containing data of 17 patients, were eventually included in the analysis. The most common
infections were bacteremias, urinary tract, and central nervous system infections. The complication rate, like the occurrence of sepsis, was high. Cephalosporins and aminoglycosides were the most common agents used for treatment. This systematic review describes bacterial infections by
and provides information on the epidemiology, clinical presentation, antibiotic resistance, treatment, and outcomes associated with these infections.
Current approaches to the cooperative control of network systems are based on a priori knowledge about the (follower) system dynamics: either the dynamics are known, or assumed to be minimum phase, ...or initial stabilizing controllers are available for each system. The purpose of this article is to show that for single-input single-output systems (SISO) the above assumptions can be relaxed. We propose an indirect adaptive methodology that does not require the knowledge of the parameters of the systems, or the systems to be minimum phase, or initial stabilizing controllers, in order to guarantee asymptotic tracking.
The efficient use of the road network for freight transport has a big impact on travel times, pollution, and fuel consumption, as well as on the mobility of passenger vehicles. In today's road ...network, truck drivers make uncoordinated selfish routing decisions, which may easily congest an initially uncongested route as many truck drivers make the same selfish decision by choosing the same route in an effort to minimize their travel time without accounting for the fact that others do the same, given the same available traffic information. In this paper, we propose a coordinated system for truck drivers, using monetary incentives and fees, to balance the traffic load and improve the overall traffic conditions and time delays experienced by both truck and passenger vehicle drivers. The basic characteristics of the mechanisms presented are that they are budget balanced, do not penalize the truck drivers compared to the user equilibrium, and they assume voluntary participation. Two models of voluntary participation are considered: weak and strong voluntary participation. In the first, each one of the drivers prefers all the drivers (including self) to participate in the mechanism than not. In the second model, each one of the truck drivers prefers to participate in the system, provided that all the others do. For each model of voluntary participation, an incentive mechanism is designed. A special emphasis is given to the fairness of the proposed mechanisms. The numerical examples are used to demonstrate the results and the efficiency of the solution techniques.
Although the roll-streak (R-S) is fundamentally involved in the dynamics of wall turbulence, the physical mechanism responsible for its formation and maintenance remains controversial. In this work ...we investigate the dynamics maintaining the R-S in turbulent Poiseuille flow at $R=1650$. Spanwise collocation is used to remove spanwise displacement of the streaks and associated flow components, which isolates the streamwise-mean flow R-S component and the second-order statistics of the streamwise-varying fluctuations that are collocated with the R-S. This partition of the dynamics into streamwise-mean and fluctuation components facilitates exploiting insights gained from the analytic characterization of turbulence in the second-order statistical state dynamics (SSD), referred to as S3T, and its closely associated restricted nonlinear dynamics (RNL) approximation. Symmetry of the statistics about the streak centreline permits separation of the fluctuations into sinuous and varicose components. The Reynolds stress forcing induced by the sinuous and varicose fluctuations acting on the R-S is shown to reinforce low- and high-speed streaks, respectively. This targeted reinforcement of streaks by the Reynolds stresses occurs continuously as the fluctuation field is strained by the streamwise-mean streak and not intermittently as would be associated with streak-breakdown events. The Reynolds stresses maintaining the streamwise-mean roll arise primarily from the dominant proper orthogonal decomposition (POD) modes of the fluctuations, which can be identified with the time average structure of optimal perturbations growing on the streak. These results are consistent with a universal process of R-S growth and maintenance in turbulent shear flow arising from roll forcing generated by straining turbulent fluctuations, which was identified using the S3T SSD.
•The stability properties of the cell transmission traffic model are analyzed.•The capacity drop phenomenon is considered.•The steady-state flow may be lower than the maximum value in the open-loop ...system.•The proposed variable speed limit controller guarantees maximum flow rate for all possible scenarios and initial conditions.
The cell transmission traffic flow model (CTM) has attracted considerable interest in the field of transportation due to its simplicity as well as the ability to capture most of the macroscopic traffic flow characteristics. The stability properties of the CTM under different demand and capacity constraints are not always obvious. In addition, the impact of microscopic phenomena such as forced lane changes at bottlenecks leading to capacity drop is not captured by the CTM. In this paper, we start with a single section and modify the CTM to account for capacity drop. We analyze the stability properties of the CTM under all possible demand and capacity constraints as well as all possible initial density conditions. The analysis is used to motivate the design of variable speed limit (VSL) control to overcome capacity drop and achieve the maximum possible flow under all feasible traffic situations. The results are extended to multiple sections, where the stability properties of the open-loop system are analyzed and a VSL control scheme is designed and shown to achieve the objective of maximizing the traffic flow under different demand and capacity constraints. Unlike the open loop system where an infinite number of equilibrium points exist under certain demand levels, the proposed nonlinear VSL scheme guarantees exponential convergence to a unique equilibrium point that corresponds to maximum possible flow and speed under all possible demand levels and capacity constraints.
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