Search results for "MIM"

Microbeam SEE Analysis of MIM Capacitors for GaN Amplifiers

2018

Broad-beam and microbeam single-event effect tests were performed on metal–insulator–metal capacitors with three different thicknesses of silicon nitride (Si3N4) dielectric insulator: 250, 500, and 750 nm. The broad-beam tests indicated that the devices with the thicker, 500- and 750-nm dielectric did not have a greater breakdown voltage. The surrounding structures of the capacitor were suspected to be a possible cause. Microbeam techniques made it possible to localize the failure location for the 500- and 750-nm devices. The failure occurs in the air bridge structure connected to the top capacitor plate, which can therefore be considered as an edge effect, while for the 250-nm devices, the…

First principles defect energetics for simulations of silicon carbide under irradiation: Kinetic mechanisms of silicon di-interstitials

2014

Understanding the modification of the properties of silicon carbide under irradiation from the very fundamental point of view of atomic bonds and electronic structure can become possible in the next few years, thanks to the effort made in the last two decades to understand point defects from first principles calculations, but also thanks to the coupling of these results with simulation tools designed to describe larger spatial (and temporal) scales. We discuss some of the missing tiles that would allow to advance in this direction, in particular the incomplete data on defect clusters, and we present some first principles results for small silicon aggregates. We examine the stability, migrat…

Few-body problems in nuclear astrophysics

2005

Few-body methods provide very useful tools to solve different problems important for nuclear astrophysics. Some of them are discussed below.

Designing Precoding and Receive Matrices for Interference Alignment in MIMO Interference Channels

2017

Interference is a key bottleneck in wireless communication systems. Interference alignment is a management technique that align interference from other transmitters in the least possibly dimension subspace at each receiver and provides the remaining dimensions for free interference signal. An uncoordinated interference is an example of interference which cannot be aligned coordinately with interference from coordinated part; consequently, the performance of interference alignment approaches are degraded. In this paper, we propose a rank minimization method to enhance the performance of interference alignment in the presence of uncoordinated interference sources. Firstly, to obtain higher mu…

Improved Performance in Quadrotor Trajectory Tracking Using MIMO PIλ-D Control

2022

This paper aims to develop a fractional control approach for quadrotor trajectory tracking. A fractional-order integrator (PIλ) with a feedback derivative scheme is designed to control each state of the MIMO system. The designed feedback controller stabilizes the initially unstable decoupled states and widens the stability, while PIλ provides precise trajectory tracking capabilities. After a successful simulation study, the new PIλ-D controller is implemented in the hardware environment. The various performance and load disturbance analyses reveal the effectiveness of the proposed scheme compared with the classical PD/PID controllers. The real-time study also shows that this scheme is a sim…

Thoureau, Wright e il guscio della tartaruga. La questione della mimesi nell’organicismo digitale e le sue implicazioni teoriche

2020

This paper deals with the complex relationship between the observation of nature and the development of digital- design processes. This relationship reveals itself aporetic particularly if the concept of mimesis has been clarified. This contribution focuses on some projects that may be ascribed in digital organicism. Challenged by the observation of “The Elephant house” by Markus Schietsch Architekten in Zurich, the paper refers to some fundamental texts that show how an explicit and structured theory may help to avoid a new sublimation of the technique through miming natural forms.

Roving Robots Gain from an Orientation Algorithm of Fruit Flies and Predict a Fly Decision-Making Algorithm

2014

Simple organisms like bacteria are directly influenced by momentary changes in concentration or strength of sensory signals. In noisy sensory gradients frequent zigzagging reduces the performance of the cell or organism. Drosophila melanogaster flies significantly deviate from a direct response to sensory input when orienting in gradients. A dynamical model has been derived which reproduces fly behaviour. Here we report on an emergent property of the model. Implemented in a robot, the algorithm is sustaining decisions between visual targets. The behaviour was consequently found in wild-type flies, which stay with a once-chosen visual target for considerable longer times than mutant flies wi…

A 16QAM super-orthogonal space-frequency code for broadband mobile communication systems with two transmit antennas

2010

We combine our previously designed 32-state super-orthogonal space-time trellis code (SOSTTC) with orthogonal frequency division multiplexing (OFDM) to build a broadband mobile communication system having a spectral efficiency that amounts to 4 bits/s/Hz depending on the length of the cyclic prefix used to avoid interframe interference. The transmitter is equipped with two antennas, where the OFDM frames they transmit are not independent, as they carry the same information in an orthogonal form. The 2N OFDM tones are grouped in N pairs of tones. Each group of two tones transmits the entries of a 2×2 orthogonal matrix. In our case, the entries are symbols taken from the rectangular 16-point …

A Wideband One-Ring MIMO Channel Model Under Non-Isotropic Scattering Conditions

2008

In this paper, we present a wideband one-ring multiple-input multiple-output (MIMO) channel model for non-isotropic scattering environments. The model is designed in such a way that the delay power spectral density (PSD) of the resulting reference channel model is identical to a given delay PSD. Furthermore, we present an efficient deterministic channel simulation model obtained by using the principle of deterministic channel modeling. The statistical properties of both the reference model and the simulation model are also studied. Analytical expressions will be presented for the temporal autocorrelation function (ACF), the two-dimensional (2D) space cross-correlation function (CCF), and th…

1988

Quercomys bijmai gen. nov. sp. nov., a new dormouse of the subfamily Myomiminae, is described from the Oligocene/Miocene Boundary Interval of Santa Cilia (Huesca), Quel-1 and Fuenmayor-2 (La Rioja). Quercomys gen. nov. is characterized by its medium size, its hypsodont teeth, and its simple dental pattero. It is related to other genera, like Praearmantomys, Armantomys or Pseudodryomys , and its appearance is at a moment of high diversity of the family.