Orlando R. Baiocchi

Pulse propagation in superconducting coplanar striplines

The phenomenological loss equivalence method (PEM), the enhanced two-fluid model for thin-film superconducting materials, and the dynamical calculation of radiation losses in planar structures are used-in the context of a linear filter approach-to model attenuation and dispersion of ultrafast pulses in coplanar striplines. The numerical simulation of this modeling shows excellent agreement with experimental results available in the literature. Simple relationships between the peak attenuation and delay time of the propagation pulse, and penetration depth at absolute zero and conductivity at critical temperature may open the possibility of using pulse distortion to characterize thin-film, high-temperature superconducting materials. >

Effects of superconducting losses in pulse propagation on microstrip lines

An analysis of the effect of losses in the propagation of pulses on superconducting microstrip lines is presented. It is based on the phenomenological equivalence method (PEM) and the two-fluid model of superconductivity to calculate the propagation characteristics of the superconducting line. For most practical situations, it is shown that these losses do not introduce phase distortion, and the attenuation constant can be approximated by a quadratic expression of the frequency. Therefore, the effect of attenuation can be easily evaluated through a simple equivalent filter.<<ETX>>

A comparison of the definitions for smart sensors, smart objects and Things in IoT

The Internet of Things has received tremendous attention. Large amount of research results have been published in recent years. However, there is a lack of clarity in the terminologies used in the literature. This paper compares the definitions of smart sensors, smart objects and the “things” in Internet of Things. Similarities and differences have been identified.

The Influence of Diffraction and Dispersion on the Fidelity of Degenerate Convolution

Both diffraction and dispersion degrade the signal processing fidelity of acoustic surface wave (ASW) convolvers. It is shown that both effects can be simulated on a model convolver by means of linear passive pre or post-distortion filters. In practice, a degree of compensation can be achieved by using inverse networks. Emphasis is placed on deriving design formulas that allow distortion levels to be estimated without extensive computation. Distortion network characteristics required are related to convolver layout. A number of typical design examples are considered.

Modeling of Dispersion Effects in Optical Systems

Modern optical transmission and optical signal processing systems make use of pulses of extremely short duration, as in the order of a picosecond (10−12s). Pulses of further shorter duration, as in the order of a femtosecond (10−15 s) have been currently obtained in laboratory experiments, and may become useful for these systems as well. Distortion of pulse profiles in dispersive channels is a problem of concern in most communication and data transmission systems. What is peculiar to the new optical systems is that traditional methods of evaluation of dispersion effects, like the parabolical approximation of the dispersion function, are no longer applicable.

Development of a Smart Building Wireless Sensors Network: Cooperation between University of Washington Tacoma and Brazilian universities

The Institute of Technology at the University of Washington Tacoma - UWT is expanding its international cooperation by hosting Brazilian undergraduate and graduate students in the Computer Engineering and Systems program. In the first research project originated from this cooperation we propose a generic and scalable system, based on Wireless Sensor Networks (WSN). Using the data acquired from the sensor nodes this system will be able to take simple decisions, such as turn on/off heater and lights and help in other more complex decisions, such as rearranging rooms based on the occupancy. These actions aim to save resources and make buildings more comfortable and efficient. In this paper we describe how this research project is being structured and conducted in order to maximize the cooperation between Brazilian and UWT researchers. Also, we show which strategies are being adopted to make the project scalable and generic. This will allow us to aggregate multi-disciplinary people and make the knowledge and technology produced to be reusable by future project members.

Identifying parking spaces & detecting occupancy using vision-based IoT devices

The increasing number of vehicles in high density, urban areas is leading to significant parking space shortages. While systems have been developed to enable visibility into parking space vacancies for drivers, most rely on costly, dedicated sensor devices that require high installation costs. The proliferation of inexpensive Internet of Things (IoT) devices enables the use of compute platforms with integrated cameras that could be used to monitor parking space occupancy. However, even with camera-captured images, manual specification of parking space locations is required before such devices can be used by drivers after device installation. In this paper, we leverage machine learning techniques to develop a method to dynamically identify parking space topologies based on parked vehicle positions. More specifically, we designed and evaluated an occupation detection model to identify vacant parking spaces. We built a prototype implementation of the whole system using a Raspberry Pi and evaluated it on a real-world urban street near the University of Washington campus. The results show that our clustering-based learning technique coupled with our occupation detection pipeline is able to correctly identify parking spaces and determine occupancy without manual specication of parking space locations with an accuracy of 91%. By dynamically aggregating identied parking spaces from multiple IoT devices using Amazon Cloud Services, we demonstrated how a complete, city-wide parking management system can be quickly deployed at low cost.

On Harvesting Energy from Tree Trunks for Environmental Monitoring

This work describes an experimental study on the possibilities of harvesting energy from tree trunks in order to power sensor nodes for environmental monitoring, particularly in wild forests. As the trunk of a living tree can be divided into isothermal subvolumes, which are generally referred to as annual rings, and the trunk is a good heat storage material, depending on the tree dimensions and its species, it can potentially offer different temperature gradients according to the tree trunk depths. The hypothesis is to consider the application of this temperature gradient on the faces of a Peltier cell to obtain electrical energy. In order to evaluate this hypothesis, a wireless sensor network was developed for measuring internal temperature of trunks from different trees. The experimental results show that it is possible to obtain a sufficient temperature gradient to harvest energy from tree trunks. Additionally, it is also shown that it is possible to harvest thermal energy during the day and during the night while photovoltaic cell only works under sunlight.

Visualization of pulse propagation phenomena with MATLAB and Wavefront software

Propagation of electromagnetic pulses in transmission lines, waveguides, and optical fibers is an important topic in the design of telecommunication, signal processing, and VLSl systems. Modern undergraduate and graduate programs in electrical and computer engineering often include this topic in their curricula. Static displays of scalar or vector fields are usually not sufficient to illustrate the complexity of the propagation process, particularly when dispersion and attenuation are considered. We describe use of the MATLAB and WAVEFRONT Data Visualizer software to provide a dynamic view of the pulse propagation process in a variety of situations. The propagation process itself is described by a cascade of linear filters that represent different mechanisms of signal distortion. The modeling and simulation of this process are performed using MATLAB. Data are then filtered and exported into WAVEFRONT. Libraries of signal waveforms and filters are provided for a variety of common configurations used in optical and microwave engineering. Extension of this work to cover nonlinear propagation effects is under investigation.

Study of eigenmode propagation and simulation of multiconductor microstrip transmission line crosstalk

The time response of coupled microstrip transmission line, obtained by modal analysis in frequency domain, has been studied. The authors have examined both voltage and current waves at each frequency component of the source by writing them explicitly in terms of eigenmodes. It is seen that, in general, all eigenmodes, whose numbers are equal to the number of signal conductors, are present in both voltage and current waves. Each eigenmode in turn contains forward and backward traveling components whose amplitudes are determined by terminal conditions. It is also pointed out that eigenmodes travel at slightly different velocities from each other. However, if the line is lossless the velocities for each eigenmodes are independent of frequency.<<ETX>>