On second-order differential equations with highly oscillatory forcing terms

We present a method to compute efficiently solutions of systems of ordinary differential equations that possess highly oscillatory forcing terms. This approach is based on asymptotic expansions in inverse powers of the oscillatory parameter,and features two fundamental advantages with respect to standard ODE solvers: rstly, the construction of the numerical solution is more efficient when the system is highly oscillatory, and secondly, the cost of the computation is essentially independent of the oscillatory parameter. Numerical examples are provided, motivated by problems in electronic engineering

CCNoC: Specializing On-Chip Interconnects for Energy Efficiency in Cache-Coherent Servers

Abstract—Manycore chips are emerging as the architecture of choice to provide power efficiency and improve performance, while riding Moore’s Law. In these architectures, on-chip interconnects play a pivotal role in ensuring power and performance scalability. As supply voltages begin to level off in future technologies, chip designs in general and interconnects in particular will require specialization to meet power and performance objectives. In this work, we make the observation that cache-coherent manycore server chips exhibit a duality in on-chip network traffic. Request traffic largely consists of simple control messages, while response traffic often carries cache-block-sized payloads. We present Cache-Coherence Network-on-Chip (CCNoC), a design that specializes the NoC to fit the demands of server workloads via a pair of asymmetric networks tuned to the type of traffic traversing them. The networks differ in their datapath width, router microarchitecture, flow control strategy, and delay. The resulting heterogeneous CCNoC architecture enables significant gains in power efficiency over conventional NoC designs at similar performance levels. Our evaluation reveals that a 4x4 mesh-based chip multiprocessor with the proposed CCNoC organization running commercial server workloads is 15-28 % more energy efficient than various state-of-the-art singleand dual-network organizations. I

Grassroots Agency: Participation and Conflict in Buenos Aires Shantytowns seen through the Pilot Plan for Villa 7 (1971–1975)

open access articleIn 1971, after more than a decade of national and municipal policies aimed at the top-down removal of shantytowns, the Buenos Aires City Council approved the Plan Piloto para la Relocalización de Villa 7 (Pilot Plan for the Relocation of Shantytown 7; 1971–1975, referred to as the Pilot Plan hereinafter). This particular plan, which resulted in the construction of the housing complex, Barrio Justo Suárez, endures in the collective memory of Argentines as a landmark project regarding grassroots participation in state housing initiatives addressed at shantytowns. Emerging from a context of a housing shortage for the growing urban poor and intense popular mobilizations during the transition to democracy, the authors of the Pilot Plan sought to empower shantytown residents in novel ways by: 1) maintaining the shantytown’s location as opposed to eradication schemes that relocated the residents elsewhere, 2) formally employing some of the residents for the stage of construction, as opposed to “self-help” housing projects in which the residents contributed with unpaid labor, and 3) including them in the urban and architectural design of the of the new housing. This paper will examine the context in which the Pilot Plan was conceived of as a way of re-assessing the roles of the state, the user, and housing-related professionals, often seen as antagonistic. The paper argues that residents’ fair participation and state intervention in housing schemes are not necessarily incompatible, and can function in specific social and political contexts through multiactor proposals backed by a political will that prioritizes grassroots agency

Motion direction control of a robot based on chaotic synchronization phenomena

This work presents chaotic motion direction control of a robot and especially of a humanoid robot, in order to achieve complete coverage of the entire work terrain with unpredictable way. The method, which is used, is based on a chaotic true random bits generator. The coexistence of two different synchronization phenomena between mutually coupled identical nonlinear circuits, the well-known complete chaotic synchronization and the recently new proposed inverse π-lag synchronization, is the main feature of the proposed chaotic generator. Computer simulations confirm that the proposed method can obtain very satisfactory results in regard to the fast scan of the entire robot’s work terrain

Analysis and adaptive control of a novel 3-D conservative no-equilibrium chaotic system

First, this paper announces a seven-term novel 3-D conservative chaotic system with four quadratic nonlinearities. The conservative chaotic systems are characterized by the important property that they are volume conserving. The phase portraits of the novel conservative chaotic system are displayed and the mathematical properties are discussed. An important property of the proposed novel chaotic system is that it has no equilibrium point. Hence, it displays hidden chaotic attractors. The Lyapunov exponents of the novel conservative chaotic system are obtained as L1 = 0.0395, L2 = 0 and L3 = −0.0395. The Kaplan-Yorke dimension of the novel conservative chaotic system is DKY =3. Next, an adaptive controller is designed to globally stabilize the novel conservative chaotic system with unknown parameters. Moreover, an adaptive controller is also designed to achieve global chaos synchronization of the identical conservative chaotic systems with unknown parameters. MATLAB simulations have been depicted to illustrate the phase portraits of the novel conservative chaotic system and also the adaptive control results

Experimental evidence of quint points and non-quantum chirality in a minimalist autonomous electronic oscillator

Recent intensive simulations have uncovered remarkable phenomena in stability diagrams of classical oscillators, for instance, quint points, parameter rings, and chiral structures of non-quantum origin. So far, their experimental observation has remained elusive. Here, using a simple electronic circuit, we report the experimental detection of five phases of oscillation spread around a quint point, an exceptional point where five oscillatory modes meet. This finding corroborates predictions of non-quantum chirality in the control parameter space of nonlinear oscillators governed by rate equations

Analysis, adaptive control and synchronization of a novel 4-D hyperchaotic hyperjerk system and its SPICE implementation

A hyperjerk system is a dynamical system, which is modelled by an nth order ordinary differential equation with n 4 describing the time evolution of a single scalar variable. Equivalently, using a chain of integrators, a hyperjerk system can be modelled as a system of n first order ordinary differential equations with n 4. In this research work, a 4-D novel hyperchaotic hyperjerk system has been proposed, and its qualitative properties have been detailed. The Lyapunov exponents of the novel hyperjerk system are obtained as L1 = 0:1448;L2 = 0:0328;L3 = 0 and L4 = −1:1294. The Kaplan-Yorke dimension of the novel hyperjerk system is obtained as DKY = 3:1573. Next, an adaptive backstepping controller is designed to stabilize the novel hyperjerk chaotic system with three unknown parameters. Moreover, an adaptive backstepping controller is designed to achieve global hyperchaos synchronization of the identical novel hyperjerk systems with three unknown parameters. Finally, an electronic circuit realization of the novel jerk chaotic system using SPICE is presented in detail to confirm the feasibility of the theoretical hyperjerk model

A chaotic path planning generator based on logistic map and modulo tactics

A simple, short and efficient chaotic path planning algorithm is proposed for autonomous mobile robots, with the aim of covering a given terrain using chaotic, unpredictable motion. The proposed technique utilizes the logistic map with a chaotic tactic that utilizes a modulo function to produce a sequence of directions for a robot that can move in eight different directions on a grid. Extensive simulations are performed, and the results show a fast and efficient scanning of the given area. In addition, the proposed algorithm is further enhanced with a pheromone inspired memory technique, with good improvements in efficiency. © 2019 Elsevier B.V