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This work presents the development of a tracking system for a three-wheeled omnidirectional mobile robot. This kind of robot can perform rotation and translation in any pose. The arc-length segment described by the omni-wheels controls the trajectory of the robot. We present a simplified kinematic model in state-space. The observation system is based on an UltraWide Band ranging sensor. Finally made the state estimation using some classic positioning algorithms and compare the results against Finite Impulse Response Filter state estimators.

The H₂ finite impulse response (FIR) filtering approach allows for optimal object tracking under harsh industrial conditions. In this brief, we propose a bias-constrained H₂ optimal unbiased FIR (H₂-OUFIR) filter for linear discrete time-invariant systems under bounded disturbances, data errors, and initial errors. The H₂-OUFIR filter is derived using the backward Euler method by minimizing the squared Frobenius norm of the weighted transfer function. A bias-constrained suboptimal H₂ FIR filtering algorithm using a linear matrix inequality (LMI) is also designed. Based on experimental examples of global positioning system (GPS)-based vehicle tracking and video human tracking, it is shown that the batch H₂-OUFIR filter operating on short horizons with full error matrices is able to outperform the Kalman, optimal finite impulse response (OFIR), and unbiased finite impulse response (UFIR) filters.

This article presents a novel alternative for measuring the heat power generated by microelectronic devices during their designing stages. The proposed system is comprised of an uncommon geometry and a signal-processing measuring strategy based on the calorimetric principle and natural convection. The calorimeter is nonconventional compared to others proposed in the literature because it does not require an external power supply or internal moving parts. Therefore, this device features a low-cost operation. In addition, the calorimeter’s geometry and design make able to be implemented at any place, as well as enhancement-adaptable. Furthermore, the thermal behavior is studied based on experimental data and numerical simulations to characterize the system properly. Thus, the calorimeter is modeled as a Cauchy problem by an ordinary differential equation to find the transient time constant. Several testing devices ranging from 1 to 20 W were used. Therefore, an algorithm was developed to determine the net heat power in a reduced time. The slowest procedure identified using the proposed algorithm is a 1-W device with less than a half-time constant. Finally, the time reduction when employing devices with power dissipation higher than 20 W is also discussed.

Information loss often occurs in industrial processes under unspecified impacts and data errors. Therefore robust predictors are required to assure the performance. We design a one-step H2 optimal finite impulse response (H2-OFIR) predictor under persistent disturbances, measurement errors, and initial errors by minimizing the squared weighted Frobenius norms for each error. The H2-OFIR predictive tracker is tested by simulations assuming Gauss-Markov disturbances and data errors. It is shown that the H2-OFIR predictor has a better robustness than the Kalman and unbiased FIR predictor. An experimental verification is provided based on the moving robot tracking problem

In this article, the multipass optimal finite impulse response (OFIR) filtering approach is developed for industrial processes with unknown initial conditions under temporary model mismatches. The forward and backward OFIR filters are derived in batch and fast iterative forms using recursions. The double-pass OFIR (DOFIR) filter supported by the unbiased FIR (UFIR) filter and triple-pass OFIR (TOFIR) filter starting with some initial values are designed and extensively investigated using simulations and experimental data. It is shown that the DOFIR and TOFIR filters are able to essentially improve the performance close to the initial values and are more robust against temporary model mismatches than the Kalman, OFIR, and UFIR filters.

It is known that due to uncertain delays and missing data wireless sensor networks (WSNs) may incur a significant loss in performance. In this work, we solve the problem in discrete-time state-space by developing the unbiased finite impulse response (UFIR) filter, Kalman filter (KF), and game theory H ∞ filter for systems with randomly delayed data and packet dropouts. The binary Bernoulli distribution is adopted for WSN channels to model the arrival data with supposedly known delay-time probability. The effectiveness of the UFIR filter, KF, and H ∞ filter is compared experimentally in terms of accuracy and robustness employing the GPS-measured vehicle coordinates transmitted with latency over WSN.

This paper describes a way to improve the indoor navigation of mobile robots using radio frequency identification (RFID) technology. A net of RFID tags is deployed in the navigation space. A measurement system measures distances from the tags to the robot with in the presence of the firstorder Markov-Gauss colored measurement noise (CMN) and is combined with a digital gyroscope to measure the robot heading. To increase the localization accuracy, the Kalman filter (KF) and unbiased finite impulse response (UFIR) modified for CMN are used. It is shown that the navigation system developed is more accurate than the basic one employing the standard KF and UFIR filter

Viewing sector optimisation allows reaching a maximum available localisation accuracy in indoor environments using optimal estimators. In this study, the authors provide such an optimisation for multi-lateration by employing the unbiased finite impulse response (UFIR) filtering technique, which ignores noise and initial values. The authors consider the unilateral deployment of anchor nodes and show, both theoretically and experimentally, that the optimal angle of arrival is zero, optimal viewing angle is π / 2 , acceptable viewing angle ranges as π / 4 … 3 π / 4 and nodes density k increases the localisation accuracy as a reciprocal of the root square of k. Experimental verification is provided using the ultra-wide band indoor precise localisation technology, in which the distance is measured via the time of arrival.

This paper develops an unbiased finite impulse response (UFIR) filtering algorithm for networked systems where uncertain delays and packet dropouts can happen due to measurement failures and unreliable communication. The binary Bernoulli distribution with known delay probability is used to model the randomly arrived measures. A novel representation of the stochastic model is presented for FIR-type filter structures. To avoid packet dropouts and improve the estimation accuracy when a message arrives with no data, a predictive algorithm is used. An advantage of the UFIR filtering approach is demonstrated by comparing the mean square errors with the Kalman and H ∞ filters under the same conditions. Experimental verifications are provided based on GPS vehicle tracking.

The electrocardiogram (ECG) signals provide information for making decisions about different kinds of heart diseases. During decades various approaches have been developed to denoise ECG data and extract useful features, although further increase in the accuracy is required. In this paper, we view the ECG signal as a quasi periodic process and employ the unbiased finite impulse response (UFIR) smoother on optimal horizons. It is shown that the UFIR smoother applied to a harmonic ECG model performs better than that recently developed for polynomial ECG models. Extensive investigation are provided for diverse ECG data. The results are compared in terms of the mean square error and signal-to-noise ratio.

Visual object tracking is commonly accompanied with large variations in the image frame size and position, as caused by the object dynamics and low frame rate. In this paper, we treat such variations as a Gauss-Markov colored measurement noise (CMN), modify the Kalman filter and unbiased finite impulse response filter using the backward Euler method and employing measurement differencing, and apply to some simulated and benchmark data. It is shown that the modified filters can suppress efficiently both the slow frame variations associated with CMN and fast variations associated with white noise. Extensive experimental investigations conducted for the "Car4" benchmark database has demonstrated a high efficiency of the modified algorithms.

Early detection of different levels of tremors helps to obtain a more accurate diagnosis of Parkinson&rsquo, s disease and to increase the therapy options for a better quality of life for patients. This work proposes a non-invasive strategy to measure the severity of tremors with the aim of diagnosing one of the first three levels of Parkinson&rsquo, s disease by the Unified Parkinson&rsquo, s Disease Rating Scale (UPDRS). A tremor being an involuntary motion that mainly appears in the hands, the dataset is acquired using a leap motion controller that measures 3D coordinates of each finger and the palmar region. Texture features are computed using sum and difference of histograms (SDH) to characterize the dataset, varying the window size, however, only the most fundamental elements are used in the classification stage. A machine learning classifier provides the final classification results of the tremor level. The effectiveness of our approach is obtained by a set of performance metrics, which are also used to show a comparison between different proposed designs.

Backward filtering is a useful tool to compute initial values in finite horizon signal processing. To make it optimally, a backward a posteriori optimal finite impulse response (B-OFIR) state estimator (filter) is proposed for discrete time-varying linear processes. The B-OFIR filter is derived in a discrete convolution-based batch form and represented with a fast iterative algorithm using recursions. The performance of the B-OFIR filter is compared to the forward OFIR filter (F-OFIR), KF, and unbiased FIR filter (UFIR). Simulations conducted based on a two-state tracking model and one degree-of-freedom torsion load system show that the B-OFIR filter is statistically equivalent to the F-OFIR filter, but operates with noise samples ordered back in time and therefore produces a bit different estimates.

We used a Fourth-Order Runge-Kutta in the Interaction Picture Method for simulating supercontinuum generation (SCG) in a designed solid-core photonic crystal fiber (PCF) with zero dispersion wavelength (ZDW) at 800 nm and other solid-core PCF with ultra-flattened dispersion in the range of 1300 nm to 1550 nm obtaining a SCG with a bandwidth of 850, 1200, and 2300 nm using a femtosecond laser in the three communication windows. Here we achieved ZDW close to the first, second and third communication windows which gives us the possibility to obtain a wide spectrum at these points with good quality in the 40-dB bandwidth for SCG with flat spectrum. The design of the two PCFs proposed here is analyzed numerically using finite element method (FEM) and we showed the results when we used a pump wavelength in normal and anomalous dispersion regimes close to ZDW points of these two PCFs for SCG.

In smart cities, vehicles tracking is organized to increase safety by localizing cars using the Global Positioning System (GPS). The GPS-based system provides accurate tracking but is also required to be reliable and robust. As a main estimator, we propose using the unbiased finite impulse response (UFIR) filter, which meets these needs as being more robust than the Kalman filter (KF). The UFIR filter is developed for vehicle tracking in discrete-time state-space over wireless sensor networks (WSNs) with time-stamped data discretely delayed on k-step-lags and missing data. The state-space model is represented in a way such that the UFIR filter, KF, and H∞ filter can be used universally. Applications are given for measurement data, which are cooperatively transferred from a vehicle to a central station through several nodes with k-step-lags. Better tracking performance of the UFIR filter is shown experimentally.

Here we propose a simple design for a photonic crystal fiber using the golden ratio parameter of pitch and four rings with hexagonal structure of air holes with solid core of silica. By varying the ratio of air hole diameters inside the structure we can control the range of flattened dispersion in anomalous or normal dispersion regime close to zero dispersion wavelength (ZDW). The wide range of wavelengths of 1.19–1.83 μm with small losses for chromatic dispersion of −0.34 ± 0.66 ps/(nm-km) and 1.292–1.555 μm with chromatic dispersion of 0 ± 0.06138 ps/(nm-km), can allow the possibility of use in different engineering areas, such as supercontinuum generation, pulse reshaping, and dense-WDM (DWDM) based optical communication systems.

This paper presents the design of all-normal dispersion photonic-crystal fiber optimized for pulse-preserving supercontinuum generation near 800 nm. The supercontinuum generation is analyzed numerically addressing the role of pump pulse energy and the pump wavelength deviation from the zeroth point of third-order dispersion. We have also shown that supercontinuum generated in designed ANDi-PCF from a few nanojoule 100 fs pulses can be efficiently compressed down to a sub-10-fs pulse with a simple quadratic compressor.

In this work we analyse the fabrication of Polymer Dispersed Liquid Crystals (PDLCs) using SU8-2002-2007 photoresist and 5CB and E7 Liquid Crystals. Also we report the nonlinear optical behaviour for these materials and for Polymer Dispersed Liquid Crystals with a Twisted Cell (T-PDLC). We found that depending of several parameters, the droplets size varies from nano to micro dimensions. We report for first time, to our best knowledge, the synthesis of a SU8 Polymer Dispersed Liquid Crystal (PDLC) by using the polymer SU8 photoresist and liquid crystals (LC) and also the nonlinear behaviour of T-PDLC. We have characterized the droplets formation from nano to micron size depending of the different variables in the synthesis. We have used this PDLC in microfabrication as planar waveguides of different thickness over Si wafers. Our results also show that PDLCs present low NL optical Kerr coefficient (n2 about 10-9cm2/W) and that it is three orders of magnitude larger in T-PDLC. Nevertheless, the fabrication processes of T-PDLCs make impossible their use in microfabrication. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

El tópico de este artículo, abordará la investigación de una técnica novedosa para la compensación electrónica de la dispersión en comunicaciones por fibra óptica a larga distancia, en la cual una señal es pre-compensada eléctricamente usando un modulador diferencial Mach-Zender, controlado por filtros digitales no lineales. La dispersión cromática fue efectivamente compensada con el uso del conjugado de fase óptica en el transmisor a través de los 4000 Km de fibra mono modo (carente de no-linealidad y atenuación) en donde la dispersión es compensada para una señal de NRZ (no retorno a cero) de intensidad modulada a 10 Gb/s. La compensación de la dispersión fue confirmada midiendo la razón de error de bit y observando los diagramas de ojo detectados.

High intensities electromagnetic energy interacting with organic media gives rise to nonlinear optical effects. Hibiscus Sabdariffa is a flower whose concentrated solution presents interesting nonlinear optical properties. This organic material shows an important self-phase modulation with changes bigger than 2π. We present a diffraction ring patterns study of the Hibiscus Sabdariffa solution. Numerical results of transmittance, with refraction and simultaneous absorption, are shown.

We show experimental results for the propagation of a diffracted beam by a straight edge like initial condition in a photorefractive crystal under drift nonlinearity. We have observed that the diffracted pattern and propagation is enhanced in the form of multiple waveguides.

In this paper, design and characterization of a pH optical fiber sensor with pH sensitive dye is described. The sensor is prepared by fixing the doped plastic fiber on a fused ortosilica block surface with blue bromophenol. The surface charge of silica and the refractive index, which plays an important roll on the fiber, modifies the conditions of light propagation into the plastic optical fiber. We use the transmittance to measure the pH of a solution or fluid in a range between 5.0 and 7.0. The advantage of this sensor is that, only 2 cm of doped fiber is enough to measure the pH of a fluid in real time. The time response of the sensor reported in the present study is approximately 10 s.

Photonic crystals are periodic structures of the dielectric materials where is posible manipulate photons in many interesting ways. Photonic band gap can propagate specific wavelengths. We present the design of demultiplexer based in photonic crystals. The control of the dielectric materials, periodicity, and size of the dielectric, is very important for light propagation. In optical communications we need to work with 1.31μm and 1.55μm by the total dispersion and due to the minimum dispersions inside the fiber and therefore minimum loses. Our design of the demultiplexer is based on diference between the background and rod refractive index.

In this work the implementation of a sensor of optical fiber current is reported by means of a magnetic structure. The sensing element (magnetic structure) consists of a magnet placed in the center of a plastic membrane. The variation in the intensity of the light caused by a mirror adapted to the membrane allowed to detect the changes in the presence of a magnetic field produced by an alternating current. Its changes were detected optically. We design a circuit to convert the light to equivalent in data to be process by a PC. The data are read and by means of a program in software Labview®, is the equivalent of current according to the intensity of detected magnetic field. INTRODUCTION Accelerated changes in technology of systems of communications and arrival of systems optical that of way they replace to systems electronic that is used in this type of systems, have influenced to a great extent, so that we takes to the optic and in special case optical communications, like the door that opens new breaches and produces a great field of the investigation [2,3]. Many electronics devices like logic gates, elements of commutation and sensors, they have been replaced by optical fiber devices that have revolutionized of considerable way and which they surpass some restrictive of the electronic systems. The optical fibers are an average ideal to be used in atmospheres of high voltage of equal way, are ideal for the information transmission and taking advantage of this property also it is possible to be created devices that help us to take measurements. The conventional electrical systems are often inadequate in surroundings of high tensions and zones with interferents, local fields of industries with emanations, the optical fiber does not create east problem to us. The sensors of current based on optical fibers, are devices that are being studied and that have obtained good results [1]. ISSN 0040-2508 © 2005 Begell House, Inc. 691 J.M. ESTUDILLO-AYALA, R. ROJAS-LAGUNA,J.A. MARTIN-VELA E. ALVARADO-MENDEZ... The electronics devices to measure current discharges but unfortunately they are very expensive and that can well be alternative that they little by little allow to develop and to innovate sensors us of current done with optical fiber designed in schools of engineering for applications in electrical substations in the country, and measurements in the laboratory with greater exactitude. The sensors of current based on optical fiber have received a special attention in the recent years. This must to its immunity to the electromagnetic fields mainly; its hostile, low atmosphere robustness lost by the transmission of signals in long distances, possibility the multiplex of several signals, adjustable length of the sensible element, great bandwidth and dynamic range. They provide complete galvanic isolation when being an average dielectric; do not circulate around them electrical signals. DESIGN AND OPERATION Theory The sensor element consisted of a magnet placed in the center of a plastic membrane. The change in the intensity of the light caused by the mirror adapted to the membrane allowed to detect the changes in the presence of a magnetic field produced by an alternating current. If the implemented structure this located to a certain distance D of an electrical line driver, an electrical intensity Ielec, would be a force of Lorentz in the magnet. This force can be expressed like: m F MV H = ∇ . (1) With M and Vm being the magnetization and the volume of the magnet, respectively, and being the gradient of associated magnetic field to Ielec, the position of the magnet. If an ideal load line is considered, magnetic field H generated by Ielec to a distance D can be expressed in cylindrical coordinates like: ˆ 2 elec I B H u D θ μ π = = (2) from this expression, H ∇ it can be obtained like: 2 ˆ 2 elec r I H u D π ∇ = (3) In the equation 1 sample which the force that acts in the magnet indicates the direction of , that this throughout the radial axis. H ∇

Here we propose a simple design for a solid-core photonic crystal fiber made of silica by keeping the golden ratio (1.618) between pitch and air hole diameter Λ /d in a subset of six rings of air-holes with hexagonal arrangement. In the case when we have a pitch equal to one micron (Λ =1 μm), we need air-holes diameters d=0.618 μm in order to obtain the golden ratio parameter (Λ/d=1.618), and achieve two zero dispersion wavelength (ZDW) points at 725 nm and 1055 nm; this gives us the possibility to use this fiber in supercontinuum generation using a laser emission close to that points. We analyzed a series of fibers using this relation and show the possibilities of tunable ZDW in a wide range of wavelengths from 725 nm to 2000 nm with low losses and small effective area. In agreement with the ZDW point needed, the geometry of the structure can be modified to the point of having only three rings of air holes that surround the solid core with low losses and good confinement mode. The design proposed here is analyzed using the finite element method (FEM) with perfectly matched layers (PML), including the material dispersion directly into the model applying the Sellmeier’s equation.

We have numerically investigated the supercontinuum generation and pulse compression in a specially designed all-normal dispersion photonic crystal fiber with a flat-top dispersion curve, pumped by typical pulses from state of the art Ti:Sapphire lasers at 800 nm. The optimal combination of pump pulse parameters for a given fiber was found, which provides a wide octave-spanning spectrum with superb spectral flatness (a drop in spectral intensity of ~1.7 dB). With regard to the pulse compression for these spectra, multiple-cycle pulses (~8 fs) can be obtained with the use of a simple quadratic compressor and nearly single-cycle pulses (3.3 fs) can be obtained with the application of full phase compensation. The impact of pump pulse wavelength-shifting relative to the top of the dispersion curve on the generated SC and pulse compression was also investigated. The optimal pump pulse wavelength range was found to be 750nm < 𝜆𝑝 < 850nm, where the distortions of pulse shape are quite small (< -3.3 dB). The influences of realistic fiber fabrication errors on the SC generation and pulse compression were investigated systematically. We propose that the spectral shape distortions generated by fiber fabrication errors can be significantly attenuated by properly manipulating the pump.

We study numerically and experimentally the reflection of spatial solitons at the interface between a nonlinear saturable-type medium and a linear one. We emphasize on determining the physical conditions under which the reflected beam at the interface conserve its nondiffracting properties. Depending on the incidence angle, we find three critical regions for spatial soliton conservation after reflection. We numerically show that the nonlinear Goos–Hanchen shift can have a dramatic effect on the diffracting properties of the reflected beam.

We show that when the coherent superposition of two dark spatial solitons is used as the initial condition for an optical beam, it will form an asymmetric optical Y-junction after evolution in a nonlinear Kerr-like medium. Using a computer-generated holographic mask to provide such a required initial condition, we demonstrated that an asymmetric optical Y-junction can be formed in a photorefractive BTO crystal.

Experimental observations of 1D and 2D self-focusing in a BaTiO3 crystal under externally DC applied electric field are reported. Stationary self-focusing behaviour can be obtained with and without additional uniform illumination.

The effect of nonlinear polarization rotation in a fiber loop mirror constricted from a low-birefringent fiber was numerically examined. We have shown that it provides in itself the intensity variation of the transmission coefficient from 1 to 0 in the configuration with a 0.5 0.5 coupler and a birefringent bias rotating polarization by π 2 at one end of the fiber. By appropriate choice of the fiber parameters both normal and inverted characteristics of the interferometer can be achieved.

We reported Supercontinuum (SC) generation in standard telecom fiber using picosecond pulses of microchip laser. The pulses width is 700 ps at 1064 nm, using 57 m long of standard fiber, and the spectra extend from 700 to above 1700 nm, some 100 nm further into the visible. The physical processes leading to the formation of the continuum spectrum were studied by monitoring the growth of the SC while increasing the input power. The coupling efficiency of ours experimental setup between the microchip laser and the telecom fiber helped us to obtain this wide spectrum.

Supercontinuum generation is being widely studied due to its applications in communications, medicine and metrology. Usually, special fibers, such as photonic crystal fibers and dispersion-shifted fiber, have been utilized. However, there is few information about the potential use of standard fiber with this purpose, which shows some advantages: low cost and availability. In this work, the influence of losses due to induced macrobends on the supercontinuum generation using standard fiber was studied. The losses were introduced by wrapping 30 m in length of standard fiber on cylinders with different diameter, a nanosecond microchip laser and 1064 nm of wavelength were employed. The continuum was recorded at the fiber output by using an optical spectrum analyzer and its dynamics was analyzed by tuning the launched power. In a first stage, the fiber was used without bends generating strong firs-order Raman Stokes and a supercontinuum spectrum of 636 nm. When the fiber was wrapped in a cylinder of 0.9 cm of diameter to induce macrobends, the Raman Stokes of high order were attenuated and the output spectrum was reduced to 240 nm. Also, a peak pulse was observed, around 1030 nm, that means new frequencies were generated in the near infrared region. Thus, induced macrobends affect the supercontinuum broadening.

Este trabajo presenta el diseño e implementación de un sistema de control de acceso mediante Identificación por Radiofrecuencia (RFID, Radio Frequency Identification) controlado por una Matriz de compuertas programables (FPGA, Field Programmable Gate Array). El sistema está constituido por un par de dispositivos de adquisición de radiofrecuencia, una FPGA, un juego de etiquetas y tarjetas pasivas de identificación. Mediante una interfaz gráfica de usuario es posible controlar todo movimiento dentro de una zona determinada, desde los accesos hasta la disponibilidad de equipo; utilizando los dispositivos de adquisición de radiofrecuencia se puede acceder a la información de los usuarios autorizados, así como al control del equipo. Con este sistema es posible monitorear, administrar y reportar todo acceso de personal, movimiento de equipo o plagio de manera eficiente y evitando un gran número de errores humanos.

In this work we have modeled and characterized the near infrared coupling between a plasmonic wire and a silicon nanowire. We have studied the coupling parameters dependence on the dimensions of the directional coupler nanowires