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Today's trend of an increasing number of networked embedded devices pervades many areas. Ranging from home automation, industrial or automotive applications with a large number of different protocols, low resources and often high demands on real-time make it difficult to secure the communication of such systems. A concept of an uncoupled MAC which is able to ensure the authenticity and integrity of...
The arch project is a suite of mini-apps that have been developed with consistent coding practices, under a common infrastructural layer. Great emphasis has been placed on making the applications concise and easy to manipulate, while capturing the key performance characteristics of their proxied algorithmic classes. The suite is intended for traditional exploration of performance, portability and...
The Network Functions Virtualization (NFV) paradigm offers network operators benefits in terms of cost efficiency, vendor independence, as well as flexibility and scalability. However, in order to profit most from these features, new challenges in the area of management and orchestration of the virtual network functions (VNFs) need to be addressed.,,In particular, this work deals with the VNF chain...
This paper presents a study of the transient performance of the speed and position sensorless control of an interior permanent magnet synchronous motor (IPMSM) based on back-electromotive force (back-EMF) estimation method in the rotor reference frame. The fundamental characteristics of the estimated back-EMF, position and speed components using mathematical models of the IPMSM are analyzed. The analyzed...
This paper covers the development of the Kuutio, a 150 x 150 x150 mm autonomous balancing cube that should jump up and successfully balanced on its edge using one of its three reaction wheels. Balancing in 1 DOF was performed within submillimetre accuracy at the top corner measuring the angular rate with a gyrometer. Using high-pass and low-pass filtering, the control algorithm for motor torque was...
New ultrasound imaging and therapeutic modalities may require transducer designs that are not easily facilitated by conventional design guidelines and analytical expressions. This motivates the investigation of numerical optimization methods that can include the effect of structural layers (e.g. bonding and electrodes), electrical loading, and more than one active piezoceramic layer in the design...
Air-coupled transducers are used to conduct fast non-contact inspections in NDT. Normally, the bandwidth of a conventional transducer can be enhanced, but with a cost to its sensitivity. However, low sensitivity is very disadvantageous in air-coupled NDT. This paper presents a methodology for improving the bandwidth of an air-coupled diaphragm transducer without sensitivity loss by connecting a number...
A three-channel interleaved Power Factor Correction (PFC) based on a new digital controller STNRGPF01 [7] operating in Continuous Conduction Mode (CCM) is presented in this paper. The control structure is based on a mixed signal concept where the time critical functions such as input current control and fast over current protections are performed using analog parts. All the non-time critical functions,...
Assessment of medium nonlinearity parameter in pulse-echo mode usually demands information on the second harmonic. However, the acquisition of quantitative data on backscattered amplitude at the fundamental and second harmonic components is difficult using the same probe due to its limited bandwidth. In this paper we propose how to assess medium nonlinearity using only the fundamental harmonic and...
In this paper, a confocal radar system and its advantages especially for the range resolution in FMCW mode is presented. The confocal system offers an additional range information due to the known focus position of the lens system. The confocal system consists of two dielectric lenses like in an optical confocal system. The first lens collimates the radar beams while the second lens focuses the beams...
A model of the dependence of the refractive index on frequency in the form of a power polynomial is proposed. A high accuracy of such an approximation of the three-term Selmeyer formula is shown. A refined method of dynamic modeling of the effects of material dispersion is considered. Dependencies of the dispersion characteristics on the shape of the signal and the composition of the material of optical...
Air-coupled transducers are used to conduct fast non-contact inspections in NDT. Normally, the bandwidth of a conventional transducer can be enhanced, but with a cost to its sensitivity. However, low sensitivity is very disadvantageous in air-coupled devices. This paper presents a methodology for improving the bandwidth of an air-coupled micro-machined ultrasonic transducer (MUT) without sensitivity...
The resonance frequency of an active element in a piezoelectric ultrasonic transducer is dependent on its length scale. Inspired by natural occurring auditory systems, incorporation of elements with varying length scales in the piezoelectric transducer design can result in a wider operational bandwidth. A mathematical algorithm has been developed to define the feature of a fractal geometry called...
New ultrasound imaging and therapeutic modalities may require complex transducer designs that are not easily facilitated by conventional design guidelines. This motivates the investigation of numerical optimization methods that can include the effect of structural layers (e.g. bonding and electrodes), electrical loading, and more than one piezoceramic layer in the design and optimization procedure...
While adding new capabilities, the distributed energy resource proliferation raises great concern about challenges such as dynamic fluctuations of voltages. For example, in a volatile setting with highly uncertain renewable generation and customer consumption, it is challenging to provide reliable power and voltage prediction for operational planning purposes to mitigate risks, e.g., over-voltages...
The ever-increasing need for higher number of neural recording channels along with the stringent power and area requirements of a brain-implantable device, demand for ultra-compact and scalable channel architectures. In this paper, we will first briefly discuss the fundamental scaling issues of conventional AC- and DC-coupled neural front-ends. Next, we will analytically examine the feasibility of...
This paper proposes a novel fully differential ultra-low voltage transimpedance amplifier (TIA) based on a CMOS translinear circuit. Following a simple bias strategy, its transimpedance gain can be adjusted to the desired accuracy either by means of an external resistor or using internal voltage and current references. To a first order approach, the transresistance results independent from technological...
The paper presents a concept of designing a stable time-varying IIR narrow multi-band-stop filter. The proposed structure is based on an all-pass prototype. The stability analysis of the time-varying design is presented. In order to reduce the transient time, the varying rejection bandwidth in time is introduced. The paper also presents the idea of the LUT's (Lookup Table) to control the memory usage...
This paper presents an active disturbance rejection control (ADRC) strategy based dynamic performance improvement scheme for position sensorless interior permanent magnet synchronous motor (IPMSM) drive. In traditional high- frequency injection based sensorless control, the digital filters and the inaccurate position tracking observer used in sensorless control deteriorate the dynamic property. For...
Currently the number of applications where the data generation function is not known has been growing, making necessary the use of non-parametric estimation techniques to describe such model. Therefore, relevant questions emerge regarding the quality of the model that represents some dataset and how to quantify this quality. This article aims to evaluate some of the measurements presented in the literature...
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