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Connected Autonomous Vehicles (AV)s can transform urban transportation systems and have the potential to improve the safety and efficiency, since human errors and distractions are removed. However, these systems are vulnerable to model uncertainties, communication impairments associated with the wireless communication, and external disturbances. As a result, vehicles need to drive at low speed and
Why is it that semidefinite relaxations have been so successful in numerous applications in computer vision and robotics for solving non-convex optimization problems involving rotations? In studying the empirical performance, we note that there are few failure cases reported in the literature, in particular for estimation problems with a single rotation, motivating us to gain further theoretical u
Methane emissions from boreal and arctic wetlands, lakes, and rivers are expected to increase in response to warming and associated permafrost thaw. However, the lack of appropriate land cover datasets for scaling field-measured methane emissions to circumpolar scales has contributed to a large uncertainty for our understanding of present-day and future methane emissions. Here we present the Borea
In inverse optimal control, an optimal controller is synthesized with respect to a meaningful, a posteriori defined, cost functional. Our work illustrates the usefulness of this approach in the control of converter-based power systems and networked systems in general, and thereby in finding controllers with topological structure and known optimality properties. In particular, we design an inverse
Low-rank inducing unitarily invariant norms have been introduced to convexify problems with a low-rank/sparsity constraint. The most well-known member of this family is the so-called nuclear norm. To solve optimization problems involving such norms with proximal splitting methods, efficient ways of evaluating the proximal mapping of the low-rank inducing norms are needed. This is known for the nuc
G.fast is a gap-bridging broadband technology on the way to a fully optical access network. G.fast is deployed in hybrid fiber-copper access networks and aiming to offer ubiquitous low-cost and high-speed broadband. For network operators, it is crucial to determine the location from where to deploy G.fast, the expected network coverage, and the expected bit rates. In this paper, we perform network
Traditional network architecture design of Low Power Wide Area Networks (LPWAN) is incapable of dynamically scaling resources based on the served traffic and requires manual procedures for network capacity upgrades. Today's over-provisioning approach based on proprietary hardware (HW) would not be cost and energy efficient to cope with the ever-increasing scale of Internet of Things (IoT) devices
We prove that for k ≫; 4√n regular resolution requires length nω(k) to establish that an ErdÅ's-Rényi graph with appropriately chosen edge density does not contain a k-clique. This lower bound is optimal up to the multiplicative constant in the exponent and also implies unconditional nω(k) lower bounds on running time for several state-of-the-art algorithms for finding maximum cliques in graphs.
AI solutions seem to appear in any and all application domains. As AI becomes more pervasive, the importance of quality assurance increases. Unfortunately, there is no consensus on what artificial intelligence means and interpretations range from simple statistical analysis to sentient humanoid robots. On top of that, quality is a notoriously hard concept to pinpoint. What does this mean for AI qu
Proper irrigation scheduling and agricultural water management require a precise estimation of crop water requirement. In practice, reference evapotranspiration (ETo) is firstly estimated, and used further to calculate the evapotranspiration of each crop. In this study, two new coupled models were developed for estimating daily ETo. Two optimization algorithms, the shuffled frog-leaping algorithm
The role of the Tibetan Plateau (TP) in El Niño-Southern Oscillation (ENSO) variability is investigated using coupled model experiments with different topography setups. Removing the TP results in weakened trade winds in the tropical Pacific, an eastward shift of atmospheric convection center, a shallower mixed layer in the equatorial Pacific, and a flattened equatorial thermocline, which leads to
Epilepsy is a chronic neurological disorder affecting more than 65 million people worldwide and manifested by recurrent unprovoked seizures. The unpredictability of seizures not only degrades the quality of life of the patients, but it can also be life-threatening. Modern systems monitoring elec-troencephalography (EEG) signals are being currently developed with the view to detect epileptic seizur
We study the problem of controlling phase activations for signalized junctions in an urban transportation network using local feedback information consisting of measures of the queue-lengths at the incoming lanes of each junction. Our focus is on the validation and performance evaluation through micro-simulations of the recently proposed Generalized Proportional Allocation (GPA) controller. Previo
The Quaternary East Asian summer rainfall evolution reconstructed with the Chinese speleothem δ18O records shows the consistency throughout the region of East Asia, and has long been considered equivalent to the monsoon intensity. Its variation and teleconnection with global climate were usually interpreted by the meridional shift of the intertropical convergence zone (ITCZ). However, many other p
Q-design is a powerful method for designing approximately optimal LTI controllers and assessing the achievable control performance. Unfortunately, numerical issues are often encountered in Q-design which limits its applicability. This paper warns about two numerical pitfalls in Q-design when using H 2 costs and Laguerre-type basis functions.
We present a reflector antenna system using a circular polarization selective surface (CPSS) to realize a circular polarization (CP) equivalent to the widely used linear polarization (LP) gridded or dual-gridded reflector (DGR). The CPSS is realized by a multilayer stack of non-resonant anisotropic meander line surfaces, achieving a very wide bandwidth. The CPSS reflection and transmission dyadics
A push-pull oscillator topology that uses only one type of active device is proposed in this article. A magnetic transformer is leveraged to set positive feedback around a common-collector differential npn transistor pair, implementing the push-pull operation. This results in half the bias current for a given amplitude of oscillation, compared to more standard oscillator topologies. A thorough pha
We describe how the optimal dual controller for a discrete-time linear system can be found by approximately solving the corresponding Bellman equation using a neural network to represent the value function. We illustrate the method on an example with time-varying dynamics, where the new method is shown to give improved performance.
