A nonlinear prediction technique for parametrized families of chaotic dynamics

A simple algorithm is proposed for reconstruction of parametrized families of chaotic dynamics. This algorithm enables one to generate bifurcation diagrams which are qualitatively the same as the original ones only from several time-waveforms, without knowing an explicit form of the dynamics and information of the parameter values. The algorithm consists of two steps. First, globally smooth nonlinear predictors are computed for all time waveforms. Second, the Karhunen-Loéve transform is used to find only significant parameters contributing to the bifurcations. The algorithm is tested against two parametrized families of dynamics: the Hénon family and the coupled logistic/delayed-logistic family. © 1997 John Wiley & Sons, Inc.     

Ad hoc mobile multicast routing using the concept of long‐lived routes

Mobile ad hoc networks are recognized by their abilities to form, sustain, and deform networks on‐the‐fly without the need for any pre‐established and fixed infrastructures. This wireless multi‐hop technology requires adaptive networking protocols with low control overhead and low power consumption to operate efficiently. Existing research so far are mainly concerned with unicast routing for ad hoc mobile networks. There is a growing interest in supporting multicast communication in an ad hoc mobile environment. In this paper, the associativity‐based ad hoc multicast (ABAM) routing protocol is proposed. The concept of association stability is utilized during multicast tree discovery, selection, and reconfiguration. This allows routes that are long‐lived to be selected, thereby reducing the frequency of route reconstructions. ABAM employs a localized route reconstruction strategy in response to migrations by source, receiver, and tree nodes. It can repair an affected subtree via a single route reconstruction operation. ABAM is robust since the repair can be triggered by a node in the tree or by the migrated node itself. ABAM is also capable of handling multicast group dynamics when mobile hosts decide to join and leave an existing multicast group. Our simulation results reveal that under different mobility scenarios and multicast group size, ABAM has low communication overhead and yields better throughput performance. Copyright © 2001 John Wiley & Sons, Ltd.     

Nanoscale TEM Imaging of Hydrogel Network Architecture

In this work, the authors succeed in direct visualization of the network structure of synthetic hydrogels with transmission electron microscopy (TEM) by developing a novel staining and network fixation method. Such a direct visualization is not carried out because sample preparation and obtaining sufficient contrast are challenging for these soft materials. TEM images reveal robust heterogeneous network architectures at mesh size scale and defects at micro-scale. TEM images also reveal the presence of abundant dangling chains on the surface of the hydrogel network. The real space structural information provides a comprehensive perspective that links bulk properties with a nanoscale network structure, including fracture, adhesion, sliding friction, and lubrication. The presented method has the potential to advance the field.     

Macroeconomy driven by climate change

Clean Technologies and Environmental Policy - A simple econometric model predicting the effects of key drivers of climate change on the real GDP is constructed. It shows quantitatively how GDP is...     

Engineering Route for Stretchable, 3D Microarchitectures of Wide Bandgap Semiconductors for Biomedical Applications

Wide bandgap (WBG) semiconductors have attracted significant research interest for the development of a broad range of flexible electronic applications, including wearable sensors, soft logical circuits, and long-term implanted neuromodulators. Conventionally, these materials are grown on standard silicon substrates, and then transferred onto soft polymers using mechanical stamping processes. This technique can retain the excellent electrical properties of wide bandgap materials after transfer and enables flexibility; however, most devices are constrained by 2D configurations that exhibit limited mechanical stretchability and morphologies compared with 3D biological systems. Herein, a stamping-free micromachining process is presented to realize, for the first time, 3D flexible and stretchable wide bandgap electronics. The approach applies photolithography on both sides of free-standing nanomembranes, which enables the formation of flexible architectures directly on standard silicon wafers to tailor the optical transparency and mechanical properties of the material. Subsequent detachment of the flexible devices from the support substrate and controlled mechanical buckling transforms the 2D precursors of wide band gap semiconductors into complex 3D mesoscale structures. The ability to fabricate wide band gap materials with 3D architectures that offer device-level stretchability combined with their multi-modal sensing capability will greatly facilitate the establishment of advanced 3D bio-electronics interfaces.