In typical AI systems, we employ so-called nondeterministic reasoning (NDR), which resorts to some systematic search with backtracking in the search spaces defined by knowledge bases (KBs) . An eminent property of NDR is that it facilitates programming, especially programming for those difficult AI problems such as natural language processing for which it is difficult to find algorithms to tell...

Variations in the switching threshold voltage of memristive devices present significant challenges for their integration into large-scale circuits. In this paper, we propose to address this problem by adding a device exhibiting S-type (N-type) negative differential resistance (NDR) in series (parallel) with memristive devices. The main effect comes from the transition between lowand highconduct...

Experimental results on the electrical characteristics of Hg-alkanethiol/arenethiol-Au molecular junctions are used to develop a physical model for the hysteretic negative-differential resistance NDR for these, and possibly other, metal-molecule-metal junctions. The dependence of the room-temperature current-voltage characteristic on sweep direction and sweep rate is examined. Based on several ...

AlN/GaN double-barrier resonant tunneling diodes RTDs were grown by metal-organic chemical vapor deposition on sapphire. RTDs were fabricated via standard processing steps. RTDs demonstrate a clear negative differential resistance NDR at room temperature RT . The NDR was observed around 4.7 V with a peak current density of 59 kA /cm2 and a peak-to-valley ratio of 1.6 at RT. Dislocation-free mat...

We report a systematical study of the temperature-dependence of negative deferential resistance (NDR) from double-barrier Al0.35Ga0.65N/GaN resonant tunneling diodes grown by plasma-assisted molecular-beam epitaxy on free-standing GaN substrates. The current–voltage (I–V) characterization was done in the 6–300 K temperature range. A clear NDR signature was observed for mesa sizes of 4 × 4 μm2 a...

A terahertz quantum cascade laser is presented in which selectively placed pure AlAs barriers are used to reduce parasitic leakage currents to the conduction band continuum. The design is demonstrated to have improved temperature performance over a regrowth of the current Tmax 200 K record holder (181 K vs. 175 K). Strangely, it fails to lase below 70 K, which we attribute to negative different...

We discuss several proposed explanations for the switching and negative differential resistance (NDR) behavior seen in some molecular junctions. Several theoretical models are discussed, and we present results of electronic structure calculations on a series of substituted oligo(phenylene ethynylene) molecules. It is shown that a previously proposed polaron model is successful in predicting NDR...

The traditional implementation of resonant tunneling diodes (RTD) as a high-frequency power source always requires the utilization of negative-differential resistance (NDR). However, there are inherent problems associated with effectively utilizing the two-terminal NDR gain to achieve significant levels of output power. This paper will present a new design methodology where resonant tunneling s...

This article investigates the snow albedo changes in Colombian tropical glaciers, namely, Sierra Nevada de Santa Marta (SNSM), del Cocuy (NSC), Nevado Ruíz (NDR), Isabel (NDS), Tolima (NDT), and Huila (NDH). They are associated with possible mineral dust deposition from Sahara Desert during June July months using (SA), cover (SC), land surface temperature (LST) Moderate Resolution Imaging Spect...

Summary This paper reviews, applies, and extends recently proposed methods based on double machine learning (DML) with a focus programme evaluation under unconfoundedness. DML-based leverage flexible prediction models to adjust for confounding variables in the estimation of (a) standard average effects, (b) different forms heterogeneous (c) optimal treatment assignment rules. An multiple progra...