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The maintenance of road pavements is an essential task to prevent major deterioration and to reduce accident rates. In this task, the detection and classification of different types of cra...

This paper presents the social foraging behavior of Escherichia coli (E. Coli) bacteria based on Bacteria Foraging Optimization algorithms (BFOA) to find optimization and distributed control values. The search strategy for E. coli is very complex to express and the dynamics of the simulated chemotaxis stage in BFOA is analyzed with the help of a simple mathematical model. The methodology starts from a detailed analysis of the parameters of bacterial swimming and tumbling (C) and the probability of elimination and dispersion (Ped), then an adaptive variant of BFOA is proposed, in which the size of the chemotherapeutic step is adjusted according to the current suitability of a virtual bacterium. To evaluate the performance of the algorithm in obtaining optimal values, the resolution was applied to one of the benchmark functions, in this case the Ackley minimization function, a comparative analysis of the BFOA is then performed. The simulation results have shown the validity of the optimal values (minimum or maximum) obtained on a specific function for real world problems, with a function belonging to the benchmark group of optimization functions.

[EN] Signals obtained from sensors are widely used in different scientific fields. However, the resources to obtain the data are not always available due to structural constraints, physical, economic, environmental, and data collection failures, etc. It is in this scenario that the generation of synthetic data is established. The generation of synthetic data has several benefits, such as, reducing waiting times compared to the long periods required by some sensors to obtain large volumes of samples. In addition, the generated data can be as robust as users need it to be. For this reason, this paper presents a pseudo-realistic synthetic signal generation system for use in the validation of methods and design of experiments. The proposed signal generation method makes use of statistical models and the gradient of the signal to generate new data. The developed system is open for the public, available as a web tool., [ES] Las señales obtenidas desde sensores son ampliamente utilizadas en diferentes campos científicos. Sin embargo, no siempre se dispone de los recursos necesarios para obtener dichos datos, debido a limitaciones estructurales, físicas, económicas, ambientales, fallos en la recolección de los datos, etc. Es en este escenario limitante, donde se erige la generación de datos sintéticos. La generación de datos sintéticos tiene la característica de reducir tiempos de espera frente a los largos periodos temporales que necesitan algunos sensores para obtener grandes volúmenes de muestras. Además, los datos generados pueden llegar a ser todo lo robustos que los usuarios necesiten. Por ello este trabajo presenta un sistema de generación de señales sintéticas con carácter pseudo-realista para su uso aplicado a la validación de métodos y diseño de experimentos. El método de la generación de señales propuesto, hace uso de modelos estadísticos y el comportamiento del gradiente de la señal para ir generando nuevos datos. El sistema desarrollado se encuentra disponible públicamente como herramienta web., Este trabajo ha sido parcialmente financiado mediante el proyecto DPI2013-47347-C2-2-R.

The current technological landscape is characterized by the massive and efficient interconnection of heterogeneous devices. Sensor networks (SNs) are key elements of this paradigm; they support the local loop, the collection and early manipulation of information. Among the applications of SNs, event detection is a well-explored topic in which strategies such as collaboration, self–organization, and others have been developed in depth. In this topic, the simplest and also most used event concept approach is the threshold-based event, which is usually integrated as part of the local sensor process. This paper addresses a different perspective by discussing the evaluation of multivariate Boolean conditions with distributed variables. We propose a new algorithm (Data Retaining Algorithm for Condition Evaluation, DRACE) that reduces packet traffic while preserving time accuracy in event calculation on an adaptive approach. To facilitate understanding of DRACE, a case study is presented in the context of a logical simile titled The Problem of a Proper Defense. The algorithm supports parameters that affects the compromise between accuracy and traffic savings. To analyze its performance, 9000 executions of the algorithm have been performed. 9 configurations tested on a repository of 1000 triads of signals randomly generated. Focusing on the most accurate configuration, 99% of executions are error-free, and the number of packets is reduced by 40% on average, being between 30 and 50% in 68% of cases.

Wireless Sensor Networks (WSN) consist of devices with limited resources to explore and sense the environment in a cooperative way. Security, mainly in terms of guaranteeing the data integrity, is a primary issue for many applications, but with an extra energy cost. Thus, trade-off is required between security level and energy consumption in real applications. First of all, a brief survey about security methods, focusing in data integrity, in WSN is implemented. The objective of this paper is to propose a new data integrity method with medium security levels and low energy cost. Therefore, we propose a new and lightweight mechanism for data integrity with overlapping blocks in WSNs. Hence, an attacker will spend much time and effort to interpret and alter the packets. The experiments were performed using TinyOS 2.1 operating system and TelosB nodes for measuring the overhead in terms of energy consumption, memory, and packet size. Moreover, the receiver is able to detect tampering packets and request those retransmission data. An attacker would require huge amounts of memory and processing time to extract the original information, even for small-sized data blocks. Thus, this fact makes this approach a simple, yet effective, mechanism to protect data whilst enhancing the data integrity.

Each year, millions of dollars are invested on road maintenance and reparation all over the world. In order to minimize costs, one of the main aspects is the early detection of those flaws. Different types of cracks require different types of repairs; therefore, not only a crack detection is required but a crack type classification. Also, the earlier the crack is detected, the cheaper the reparation is. Once the images are captured, several processes are applied in order to extract the main characteristics for emphasizing the cracks (logarithmic transformation, bilateral filter, Canny algorithm, and a morphological filter). After image preprocessing, a decision tree heuristic algorithm is applied to finally classify the image. This work obtained an average of 88% of success detecting cracks and an 80% of success detecting the type of the crack. It could be implemented in a vehicle traveling as fast as 130 kmh or 81 mph.

The temperature of the forehead is known to be highly correlated with the internal body temperature. This area is widely used in thermal comfort systems, lie-detection systems, etc. However, there is a lack of tools to achieve the segmentation of the forehead using thermographic images and non-intrusive methods. In fact, this is usually segmented manually. This work proposes a simple and novel method to segment the forehead region and to extract the average temperature from this area solving this lack of non-user interaction tools. Our method is invariant to the position of the face, and other different morphologies even with the presence of external objects. The results provide an accuracy of 90% compared to the manual segmentation using the coefficient of Jaccard as a metric of similitude. Moreover, due to the simplicity of the proposed method, it can work with real-time constraints at 83 frames per second in embedded systems with low computational resources. Finally, a new dataset of thermal face images is presented, which includes some features which are difficult to find in other sets, such as glasses, beards, moustaches, breathing masks, and different neck rotations and flexions.

Wireless sensor networks are used to sample the environment in a distributed way. Therefore, it is mandatory for all of the measurements to be tightly synchronized in order to guarantee that every sensor is sampling the environment at the exact same instant of time. The synchronization drift gets bigger in environments suffering from temperature variations. Thus, this work is focused on improving time synchronization under deployments with temperature variations. The working hypothesis demonstrated in this work is that the clock skew of two nodes (the ratio of the real frequencies of the oscillators) is composed of a multiplicative combination of two main components: the clock skew due to the variations between the cut of the crystal of each oscillator and the clock skew due to the different temperatures affecting the nodes. By applying a nonlinear filtering, the homomorphic filtering, both components are separated in an effective way. A correction factor based on temperature, which can be applied to any synchronization protocol, is proposed. For testing it, an improvement of the FTSP synchronization protocol has been developed and physically tested under temperature variation scenarios using TelosB motes flashed with the IEEE 802.15.4 implementation supplied by TinyOS. This work has been partly supported by the Computer Architecture, Electronics and Electronic Technology Department at University of Cordoba (Spain), Spanish Grants P11-TIC-7462 and DPI2013-47347-C2-2-R and European Grant EEA 014-ABELCM-2013.

Thisstudyassessthedecayofapower-pulsedmicrowaveplasmainargonmixturesusingtimeresolved Thomson scattering. In argon at intermediate pressure, i.e. tens of mbar, the electrontemperature decays very fast after power off and approaches the heavy particle temperature,while the electron density decays slower, in the order of tens of microseconds. Argon withsmall admixtures of O

Time synchronisation is essential to ensure the reliability of distributed computation. Oscillators included in low-cost nodes are highly influenced by temperature variations. Experimental results demonstrate that the clock skew of two nodes (the ratio of the real frequencies of the oscillators) is composed of a multiplicative combination of, at least, two main components: the clock skew due to the variations between the cut of the crystal of each oscillator and the clock skew due to the different temperatures affecting the nodes. By applying a nonlinear filtering, homomorphic filtering, both components are separated in an effective way. Applying a correction factor to the clock skew due to the cut of the crystals, the temperature variations are compensated very accurately. The proposed new approach is called HF2 (homomorphic improved filtering) and can be easily applied to any clock-skew-based time synchronisation protocol. The correction factor has been applied to flooding time synchronisation protocol (FTSP) resulting in HF2-FTSP. An experiment with temperature variation, comparing FTSP, A2T-FTSP and HF2-FTSP is shown. The proposed technique allows the use of cheap and simple oscillators for achieving a quite similar accurate synchronisation level than much more expensive and precise oscillators.

This work analyzes several drift compensation mechanisms in wireless sensor networks (WSN). Temperature is an environmental factor that greatly affects oscillators shipped in every WSN mote. This behavior creates the need of improving drift compensation mechanisms in synchronization protocols. Using the Flooding Time Synchronization Protocol (FTSP), this work demonstrates that crystal oscillators are affected by temperature variations. Thus, the influence of temperature provokes a low performance of FTSP in changing conditions of temperature. This article proposes an innovative correction factor that minimizes the impact of temperature in the clock skew. By means of this factor, two new mechanisms are proposed in this paper: the Adjusted Temperature (AT) and the Advanced Adjusted Temperature (A2T). These mechanisms have been combined with FTSP to produce AT-FTSP and A2T-FTSP. Both have been tested in a network of TelosB motes running TinyOS. Results show that both AT-FTSP and A2T-FTSP improve the average synchronization errors compared to FTSP and other temperature-compensated protocols (Environment-Aware Clock Skew Estimation and Synchronization for WSN (EACS) and Temperature Compensated Time Synchronization (TCTS)).

We report measurements of electron densities, ${n}_{e}$, and temperatures, ${T}_{e}$, in a magnetized expanding hydrogen plasma performed using Thomson scattering. The effects of applying an axial magnetic field and changing the background pressure in the plasma vessel on ${n}_{e}$ and ${T}_{e}$ along the expansion axis are reported. Magnetic field strengths ($B$ field) up to 170 mT were applied, which are one order of magnitude larger than previously reported. The main effect of the applied $B$ field is the plasma confinement, which leads to higher ${n}_{e}$. At $B$ fields larger than 88 mT the electron density along the expansion axis does not depend strongly on the magnetic field strength. However, ${T}_{e}$ is susceptible to the $B$ field and reaches at 170 mT a maximum of 2.5 eV at a distance of 1.5 cm from the exit of the cascaded arc. To determine also the effect of the arc current through the arc, measurements were performed with arc currents of 45, 60, and 75 A at background pressures of 9.7 and 88.3 Pa. At constant magnetic field ${n}_{e}$ decreases from the exit of the arc along the expansion axis when the arc current is decreased. At 88.3 Pa ${n}_{e}$ shows a higher value close to the exit of the arc, but a faster decay along the expansion axis with respect to the 9.7 Pa case. ${T}_{e}$ is overall higher at lower pressure reaching a maximum of 3.2 eV at the lower arc current of 45 A. The results of this study complement our understanding and the characterization of expanding hydrogen plasmas.

The electron temperature of an argon surface wave discharge generated by a surfatron plasma at intermediate pressures is measured by optical emission spectroscopy (OES) and Thomson scattering (TS). The OES method, namely absolute line intensity (ALI) measurements gives an electron temperature which is found to be (more or less) constant along the plasma column. TS, on the other hand, shows a different behaviour; the electron temperature is not constant but rises in the direction of the wave propagation. In the pressure range of this study, it is theoretically known that deviations from Maxwell equilibrium are expected towards the end of the plasma column. In this paper, we propose a combination of methods to probe the electron energy distribution function (EEDF) in this relatively high-pressure regime. The ALI method combined with a collisional–radiative model allows one to measure the effective (Maxwellian) creation temperature of the plasma while TS measures the mean electron energy of the EEDF. The differences between the two temperature methods can be explained by the changes in the form of the EEDF along the plasma column. A strong correlation is found with decreasing ionization degree for different pressures. Numerical calculations of the EEDF with a Boltzmann solver are used to investigate the departure from a Maxwellian EEDF. The relatively higher electron temperature found by TS compared with the ALI measurements is finally quantitatively correlated with the departure from a Maxwellian EEDF with a depleted tail.

In the present work Stark broadening measurements have been carried out on low electron density (neb5·1019 m-3) and (relatively) low gas temperature (Tgb1100 K) argon–hydrogen plasma, under low-intermediate pressure conditions (3 mbar–40 mbar). A line fitting procedure is used to separate the effects of the different broadening mechanisms (e.g. Doppler and instrumental broadening) from the Stark broadening. A Stark broadening theory is extrapolated to lower electron density values, below its theoretical validity regime. Thomson scattering measurements are used to calibrate and validate the procedure. The results show in agreement within 20%, what validates the use of this Stark broadening method under such lowdensity conditions. It is also found that Stark broadened profiles cannot be assumed to be purely Lorentzian. Such an assumption would lead to an underestimation of the electron density. This implies that independent information on the gas temperature is needed to find the correct values of ne.

We present a time-resolved imaging and electrical study of an atmospheric pressure spark discharge. The conditions of the present study are those used for nanoparticle generation in spark discharge generator setups. The oscillatory bipolar spark discharge was generated between two identical Cu electrodes in different configurations (cylindrical flat-end or tipped-end geometries, electrode gap from 0.5 to 4 mm), in a controlled co-axial N2 flow, and was supplied by a high voltage capacitor. Imaging data with nanosecond time resolution were collected using an intensified CCD camera. This data were used to study the time evolution of plasma morphology, total light emission intensity, and the rate of plasma expansion. High voltage and high current probes were employed to collect electrical data about the discharge. The electrical data recorded allowed, among others, the calculation of the equivalent resistance and inductance of the circuit, estimations for the energy dissipated in the spark gap. By combining imaging and electrical data, observations could be made about the correlation of the evolution of total emitted light and the dissipated power. It was also observed that the distribution of light emission of the plasma in the spark gap is uneven, as it exhibits a “hot spot” with an oscillating position in the axial direction, in correlation with the high voltage waveform. The initial expansion rate of the cylindrical plasma front was found to be supersonic; thus, the discharge releases a strong shockwave. Finally, the results on equivalent resistance and channel expansion are comparable to those of unipolar arcs. This shows the spark discharge has a similar behavior to the arc regime during the conductive phase and until the current oscillations stop.

The axial profiles of the electron density ne and electron temperature Te of argon surfatron plasmas in the pressure range of 6–20 mbar and microwave power between 32 and 82 W have been determined using Thomson Scattering of laser irradiation at 532 nm. For the electron density and temperature we found values in the ranges 5 × 1018

Several active and passive diagnostic methods have been used to study atmospheric microwave-induced plasmas created by a surfatron operating at a frequency of 2.45 GHz and with power values between 57 and 88 W. By comparing the results with each other, insight is obtained into essential plasma quantities, their radial distributions and the reliability of the diagnostic methods. Two laser techniques have been used, namely Thomson scattering for the determination of the electron density, n e, and temperature, T e, and Rayleigh scattering for the determination of the heavy particle temperature, T g. In combination, three passive spectroscopic techniques are applied, the line broadening of the Hβ line to determine n e, and two methods of absolute intensity measurements to obtain n e and T e. The active techniques provide spatial resolution in small plasmas with sizes in the order of 0.5 mm. The results of n e measured with three different methods show good agreement, independent of the plasma settings. The T e values obtained with two techniques are in good agreement for the condition of a pure argon plasma, but they show deviations when H2 is introduced. The introduction of a small amount (0.3%) of H2 into an argon plasma induces contraction, reduces n e, increases T e, enhances the departure from equilibrium and leads to conditions that are close to those found in cool atmospheric plasmas.

An experimental study on the asymmetry of the Balmer Hβ profile in plasmas produced by microwaves at atmospheric pressure is presented. The study is based on the definition of several functions that quantify the asymmetry aspects of the profile. Apart from the asymmetry aspects of the flanks also form-functions are defined that characterize the central part of the profile, the so-called dip or central valley, the combination of the two peaks and the dip in between them. The study shows the experimental dependence of these characteristics on the electron density and control parameters such as the gas flow and the hydrogen admixture ratio. The possible use of these newly introduced profile characteristics to plasma diagnosis is discussed.

The aim of this work is to analyse and discuss a spectroscopic method of diagnosis based on the Stark broadening of emission lines to determine the electron density and temperature in atmospheric-pressure plasmas. Usually, when the electron temperature is previously known, the Stark broadening of certain spectral lines spontaneously emitted by the plasma is used to determine the electron density in a rapid and inexpensive way. However, comparing two or more broadening of lines can allow us to diagnose the electron density and temperature simultaneously. To carry out this cross-point method, we must know the Stark broadening dependence on the electron temperature and density for different lines. In this work we have used the first three Balmer series hydrogen lines, whose Stark broadenings were calculated by means of a recent micro-field model existing in the bibliography. The experimental study was made in argon and hydrogen plasma flames. The plasmas were produced at 2.45 GHz by an axial injection torch, which can operate at atmospheric pressure under different experimental conditions to produce appropriate plasmas in 'open air'. The flame produced in this way is a two-temperature plasma, so it is not in local thermodynamic equilibrium. Moreover, by means of the Boltzmann-plot modified with the p-6 law, we found for the hydrogen plasma that most of the observable atomic states were ruled by the excitation–saturation balance. With this method we could also determine the electron temperature.

To exploit distributed computation in wireless sensor networks (WSNs) time synchronisation protocols are required. These protocols support advanced distributed and synchronous tasks between several nodes. Temperature changes have a strong influence in oscillators and may vary the clock of the nodes. The flooding time synchronisation protocol (FTSP) is a common time-sync protocol in WSNs. It cannot deal with rapid temperature changes and needs several long periods to readjust the clock drift. Proposed is an innovative correction factor, implemented in a module called advanced adjustment temperature (A2T), that minimises the impact of temperature in the clock skew. This module may be placed on top of any clock-skew based time synchronisation protocol with minimum coding modifications. For this work, the module has been linked to the FTSP, producing A2T-FTSP. Experiments show that A2T-FTSP reduces noticeably the average synchronisation errors compared to FTSP for the same varying temperature conditions.

The reaction kinetics in the excitation space of Ar is explored by means of Laser Induced Fluorescence (LIF) experiments using the combination of high rep-rate YAG–Dye laser systems with a well defined and easily controllable surfatron induced plasma setup. The high rep-rate favors the photon statistics while the low energy per pulse avoids intrusive plasma laser interactions. An analysis shows that, despite the low energy per pulse, saturation can still be achieved even when the geometrical overlap and spectral overlap are optimal. Out of the various studies that can be performed with this setup we confine the current paper to the study of the direct responses to the laser pump action of three 4p and one 5p levels of the Ar system. By changing the plasma in a controlled way one gets for these levels the rates of electron and atom quenching and therewith the total destruction rates of electron and atom collisions. Comparison with literature shows that the classical hard sphere collision rate derived for hydrogen gives a good description for the observed electron quenching (e-quenching) in Ar whereas for heavy particle quenching (a-quenching) this agreement was only found for the 5p level. An important parameter in the study of electron excitation kinetics is the location of the boundary in the atomic system for which the number of electron collisions per radiative life time equals unity. It is observed that for the Ar system this boundary is positioned lower than what is expected on grounds of H-like formulas.

The synthesis of nanoparticles by means of electrical discharges between two electrodes in an inert gas at atmospheric pressure, as driven by a constant current ranging from a few milliamps to tens of amps, is investigated in this work. An extensive series of experiments are conducted with copper as a consumable electrode and pure nitrogen as the inert gas. Three different DC power supplies are used to drive electrical discharges for the entire operating current range. Then, three electrical discharge regimes (spark, glow, and arc) with distinct voltage–current characteristics and plasma emission spectra are recognized. For the first time, nanoparticles are synthesized by evaporation of an electrode by atmospheric pressure inert gas DC glow discharge of a few millimeters in size. The discharge regimes are characterized in terms of the mass output rate and the particle size distribution of the copper aerosols by means of online (tapered element oscillating microbalance, TEOM; and scanning mobility particle sizer, SPMS) and offline (gravimetric analysis; small and wide angle X-ray scattering, SWAXS; and transmission electron microscopy, TEM) techniques. The electrical power delivered to the electrode gap and the gas flow rate are two major parameters determining the aerosol mass output rate and the aerosol particle size distribution. The mass output rate of copper aerosols raises from 2 mg h−1 to 2 g h−1 when increasing the electrical power from 9 to 900 W. The particle mean size (SMPS d g) varies between 20 and 100 nm depending upon the electrical power and the gas flow rate, whereas the particle size dispersion (SMPS σ g) ranges from 1.4 to 1.7 and is only weakly dependent on the gas flow rate.

This paper presents a motion estimation processor based on a dual-core architecture. Both cores are based on bit-serial adder trees. Memory structures are also described. This architecture is bit-precision reconfigurable. Performance results for several smartphones and tablets are presented. Furthermore, hardware results and comparison with other works are included. Real-time processing is achieved for all devices studied.

As embedded systems are becoming prevalent in everyday life, many universities are incorporating embedded systems-related courses in their undergraduate curricula. However, it is not easy to motivate students in such courses, since they conceive of embedded systems as bizarre computing elements, different from the personal computers with which they are familiar. This problem has been overcome at the University of Granada, Spain, by taking advantage of the connection many students have with video games., Spanish CICYT Project SAF2010-20558, University of Granada Innovative Teaching Project 04-03-08

The axial dependency of the central-axis value of the heavy particle density and temperature of surface wave plasmas is studied using Rayleigh scattering (RyS). The plasma is generated at a frequency of 2.45 GHz in argon by a surfatron operating under the standard settings of a power of 45 W, a flow rate of 50 sccm and a pressure of 20 mbar. To investigate the effect of the pressure on the gas temperature we also investigated 6 and 10 mbar plasmas while keeping the other control parameters unchanged. By using a two dimensional intensified CCD array we could determine and eliminate the influence of false stray light; a mayor disturbing factor in the determination of the Rayleigh signal. In order to trace the energy fluxes that determine the gas temperature we performed Thomson scattering so that the properties of the electron gas are known. It is found that the gas temperature, Ta, depends on the wall temperature and the product of the gas pressure and the electron pressure. The later implies that Ta follows the electron density axially, meaning that it is highest at the launcher and decreases monotonically in the wave propagation direction. The maximum gas temperature of around Ta = 800 K is found close to the launcher for the highest pressure of 20 mbar. For lower pressures we find lower Ta values. In all cases, the extrapolation of Ta toward the end of the plasma column leads to a temperature of about 310 K which is close to room temperature. This study reveals that, for the argon plasmas under study, the central-axis values of the gas temperature is determined by the balance between the heating of the gas by means of elastic electron collisions and the cooling due to heat conduction from the centre to the wall.

The direct imaging capacity of a triple-grating spectrometer designed for Thomson scattering is used for a cartographic study of the end of the column created by intermediate-pressure surfatron plasmas in argon. It is shown that the electron density decreases abruptly at the very end of the column. This effect is more pronounced for higher pressures and accompanied by a large rise in electron temperature.

A criterion is given for the laser fluency (in J/m2) such that, when satisfied, disturbance of the plasma by the laser is avoided. This criterion accounts for laser heating of the electron gas intermediated by electron-ion (ei) and electron-atom (ea) interactions. The first heating mechanism is well known and was extensively dealt with in the past. The second is often overlooked but of importance for plasmas of low degree of ionization. It is especially important for cold atmospheric plasmas, plasmas that nowadays stand in the focus of attention. The new criterion, based on the concerted action of both ei and ea interactions is validated by Thomson scattering experiments performed on four different plasmas.

This paper describes a new method for License Plate Detection based on Genetic Neural Networks, Morphology, and Active Contours. Given an image is divided into several virtual regions sized 10 × 10 pixels, applying several performance algorithms within each virtual region, algorithms such as edge detection, histograms, and binary thresholding, etc. These results are used as inputs for a Genetic Neural Network, which provides the initial selection for the probable situation of the license plate. Further refinement is applied using active contours to fit the output tightly to the license plate. With a small and well-chosen subset of images, the system is able to deal with a large variety of images with real-world characteristics obtaining great precision in the detection.The effectiveness for the proposed method is very high (97%). This method will be the first stage of a surveillance system which takes into account not only the actual license plate but also the model of the car to determine if a car should be taken as a threat.

An experimental study on the asymmetry of the Balmer Hß profile in plasmas produced by microwaves at atmospheric pressure is presented. The study is based on the definition of several functions and parameters that quantify the asymmetry and different shape aspects of the profile. The study shows the experimental dependence of these characteristics on the electron density and control parameters such as the gas flow and the hydrogen admixture ratio. The possible use of these newly introduced profile characteristics to plasma diagnosis is discussed.

The Canny algorithm is a well known edge detector that is widely used in the previous processing stages in several algorithms related to computer vision. An alternative, the LIP-Canny algorithm, is based on a robust mathematical model closer to the human vision system, obtaining better results in terms of edge detection. In this work we describe LIP-Canny algorithm under the perspective from its parallelization and optimization by using the NVIDIA CUDA framework. Furthermore, we present comparative results between an implementation of this algorithm using NVIDIA CUDA and the analogue using a C/C++ approach.

Microprocessors is a typical subject within the Computer Architecture field of scope. It is quite common to use simulators in practical sessions, due to the complexity of its contents. In this paper a new methodology based on practical sessions with real devices and chips is proposed. Simple designs of microprocessors are exposed to the students at the beginning, rising the complexity gradually toward a final design with a multiprocessor integrated in a single FPGA chip. Finally, assessment results are shown.

This paper presents a study on the asymmetry of the Balmer Hβ profile in plasmas produced by microwaves at high pressure with the help of some functions of asymmetry for the whole profile, as well as by means of some specific parameters characterizing only its central dip. The study shows how this asymmetry—very low in our case—depends on the electron density and flux of gases and how the existence of inhomogeneities in the plasma can affect the shape and symmetry of this line. Also, limitations on the determination of the asymmetry are pointed out and the use of this profile for plasma diagnosis is discussed.

An absolute intensity measurement (AIM) technique is presented that combines the absolute measurements of the line and the continuum emitted by strongly ionizing argon plasmas. AIM is an iterative combination of the absolute line intensity-collisional radiative model (ALI-CRM) and the absolute continuum intensity (ACI) method. The basis of ALI-CRM is that the excitation temperature T13 determined by the method of ALI is transformed into the electron temperature Te using a CRM. This gives Te as a weak function of electron density ne. The ACI method is based on the absolute value of the continuum radiation and determines the electron density in a way that depends on Te. The iterative combination gives n e and Te. As a case study the AIM method is applied to plasmas created by torche injection axiale (TIA) at atmospheric pressure and fixed frequency at 2.45 GHz. The standard operating settings are a gas flow of 1 slm and a power of 800 W; the measurements have been performed at a position of 1 mm above the nozzle. With AIM we found an electron temperature of 1.2 eV and electron density values around 1021 m-3. There is not much dependence of these values on the plasma control parameters (power and gas flow). From the error analysis we can conclude that the determination of T e is within 7% and thus rather accurate but comparison with other studies shows strong deviations. The ne determination comes with an error of 40% but is in reasonable agreement with other experimental results. © 2009 IOP Publishing Ltd.

Thomson scattering (TS) experiments have been made on a low pressure surfatron induced plasma. TS is an active diagnostic method and the experimental results are directly related to important plasma properties such as the electron density, ne, and the electron temperature, Te. Therefore, the TS results for ne and Te can be used to calibrate passive diagnostic methods which are often based on plasma models. However, to apply TS on a surfatron induced plasma inside a quartz tube is experimentally demanding because of the large amount of stray light and a low intensity of the TS signal. To achieve low detection limits and high stray light rejection, a triple grating spectrograph was used in the detection branch and an iCCD was used to record the TS spectrum. For a typical plasma condition with an argon pressure of 10 mbar and an absorbed power of 50 W, the measured electron density was found to be equal to ne ≈ 4 × 1019 m−3 and the electron temperature Te ≈ 1.2 eV. In addition, frame-averaged results for 6, 10, 15 and 20 mbar argon plasmas for absorbed microwave powers in between 25 ≤ Pab ≤ 60 W are presented. The trends found in the dependence of the pressure and power density are according to theory.

Computer architecture science evolves continuously. This work describes a methodology to teach a system which is integrated by several processors in just one chip. The description of how to implement a biprocessor system within an FPGA is proposed. Thus, the student will simultaneously acquire advanced knowledge on microprocessors, focusing on the operational behavior and structure of a biprocessor system, which they implement in a real device. Finally, a software layer is provided to execute an application, which proves how the system works. The accomplishment of this practice has been carried out in the first four-month period of 2007 in the 4th year subject ldquoDigital Electronic Systemsrdquo of the Engineering Degree in Automatics and Electronics at the University of Cordoba.

This paper presents a computer aided diagnosis system for skin lesions. Diverse parameters or features extracted from fluorescence images are evaluated for cancer diagnosis. The selection of parameters has a significant effect on the cost and accuracy of an automated classifier. The genetic algorithm (GA) performs parameters selection using the classifier of the K-nearest neighbours (KNN). We evaluate the classification performance of each subset of parameters selected by the genetic algorithm. This classification approach is modular and enables easy inclusion and exclusion of parameters. This facilitates the evaluation of their significance related to the skin cancer diagnosis. We have implemented this parameter evaluation scheme adopting a strategy that automatically optimizes the K-nearest neighbours classifier and indicates which features are more relevant for the diagnosis problem.

The logarithmic image processing model (LIP) is a robust mathematical framework, which, among other benefits, behaves invariantly to illumination changes. This paper presents, for the first time, two general formulations of the 2-D convolution of separable kernels under the LIP paradigm. Although both formulations are mathematically equivalent, one of them has been designed avoiding the operations which are computationally expensive in current computers. Therefore, this fast LIP convolution method allows to obtain significant speedups and is more adequate for real-time processing. In order to support these statements, some experimental results are shown in Section V.

The Logarithmic Image Processing model (LIP) is a robust mathematical framework for the processing of transmitted and reflected images. It follows many visual, physical and psychophysical laws. This works presents a new formulation of a 2D–convolution of separable kernels using the LIP paradigm. A previously stated LIP–Sobel edge detector is redefined with the new proposed formulation, and the performance of the edge detectors programmed following the two formulations (the previous one and the new one proposed) is compared. Another operator, Laplacian of Gaussian, is also stated under the LIP paradigm. The experiments show that both methods obtain same results although our proposed method is much faster than the previous one.

This work presents a new global motion estimation algorithm for MPEG compressed video sequences. It makes use of a feature extraction technique based on the Generalized Hough Transform, which is able to provide rotation, scale and displacement parameters when comparing two different frames from a video sequence. Thus, pan, tilt, swing (rotation along z-axis) and zoom effects will be studied using the proposed algorithm. DC coefficients of the DCT transform are extracted from the MPEG stream and used to create DC images, which are the starting point for the global motion estimation algorithm. Further application of the feature extraction technique to DC images will allow to perform motion estimation, reducing processing time as the decompression process is avoided. Pseudocode and details about the implementation of the algorithm as well as statistics to illustrate the efficiency of the algorithm are provided.

This work presents a new video feature extraction technique based on the Generalized Hough Transform (GHT). This technique provides a way to deflne a similarity measure between two difierent frames, which establishes the basis for scene cut detection algorithms. Moreover, GHT allows to calculate the difierences between two frames in terms of rotation, scale and displacement. This provides a framework for the development of global motion estimation algorithms. In addition, gradual transition detection algorithms (fades, dissolves, etc.) can also be developed. To illustrate the posibilities of this technique, a scene cut detection algorithm is also proposed. This algorithm works with MPEG video in compressed domain, achieving real time processing. An improved thresholding technique is also stated. This technique uses two difierent sets of similarity values making the scene cut detection algorithm perform quite well with difierent types of videos. The thresholding process reports two difierent kinds of cuts: real cuts and probable cuts. Also, it detects the location of dynamic scenes, which can be used to perform further semantic analysis. Finally, the use of the improved thresholding technique and a set of optimized parameters results in an algorithm where no human intervention is needed. Several tests have been carried out using long videos, including more than 1400 cuts. Comparison with another well-known cut detection algorithm has also been performed.

Abrupt video edition effects (mainly called scene cuts) are transitions in which the image changes globally from one frame to the following one. The automatic detection of this set of effects is a research area widely analyzed, which has produced a number of working technique families. Two of these families are the methods based on geometric features of the images (basically, edges and contours) and the ones based on intensity or chromaticity of the images. Feature-based techniques are highly reliable for cut detection, but they are sometimes unfeasible due to the time spent to obtain results. Intensity-based techniques are not so accurate to detect cuts, although they work very fast. Thus a new hybrid technique is proposed. This method has been stated by combining both techniques. The intensity-based method is used to locate 'probable cuts' with a considerable speed and then the edge-based method is applied to check whether each 'probable cut' actually exists or not. This way, a great time reduction is achieved with little or no loss of accuracy. Results of five well-known algorithms for automatic cut detection are shown. Besides, the results of the proposed method are given and all of them are compared, obtaining the new technique very good results.

This work is aimed at investigating the influence of the inter-electrode spacing on the production rate and size of nanoparticles generated by evaporating a cathode on an atmospheric pressure dc glow discharge. Experiments are conducted in the configuration of two vertically aligned cylindrical electrodes in upward coaxial flow with copper as a consumable cathode and nitrogen as a carrier gas. A constant current of 0.5 A is delivered to the electrodes and the inter-electrode distance spanned from 0.5 to 10 mm. Continuous stable nanoparticle production is attained by optimal coaxial flow convection cooling of the cathode. Both the particle production rate and the primary particle size increase with the inter-electrode spacing up to nearly 5 mm and strongly decrease with an increasing inter-electrode distance beyond 5 mm. Production rates in the range of 1 mg h−1 of very small nanoparticles (−1 and primary particles of sizes between 10 and 20 nm. No correlation is found between the measured spatially averaged plasma parameters and nanoparticle production. Since the latter is largely determined by the properties of the cathode surface, spatially resolved spectrometric measurements are needed to discern between the positive column and the cathode region of the glow discharge plasma.

Radial electron density n e(r) and temperature T e(r) profiles of a microwave argon plasma at intermediate pressure were investigated by Thomson scattering. This method allows one to get n e(r) and T e(r) spatially resolved without any a priori assumption on the shape of the profile. Data were acquired in the pressure range 5–88 mbar where a transition from wall-stabilized to a radially contracted plasma mode was observed. It was found that the fitting of the radial profile can be done with a Bessel function for which the boundary radius R defined by n e(R) = 0 is a free parameter. For pressures above 20 mbar the electron density profile undergoes radial contraction, so R goes down from 3 mm at 5 mbar (wall position) to 2.09 mm at 88 mbar. The electron temperature T e(r) on the other hand is flat in the centre and rises towards the wall. For low pressures, this rise is moderate but for pressures of 20 mbar and above the increase is more pronounced.

The reaction kinetics in the excitation space of Ar and the conversion space of Ar-molecule mixtures are explored using a combination of high rep-rate YAG-Dye laser systems with a well defined and easily controllable Surfatron Induced Plasma set-up. Applying the method of Saturation Time Resolved Laser Induced Fluorescence (SaTiRe-LIF), we could trace excitation and conversion channels and determine rates of electron and heavy particle excitation kinetics. The time resolved density disturbances observed in the Ar excitation space, which are initiated by the laser, reveal the excitation channels and corresponding rates; responses of the molecular radiation in Ar-molecule mixtures corresponds to the presence of conversion processes induced by heavy particle excitation kinetics.

A route toward the experimental characterization of Cool Atmospheric Plasmas (CAPs) is described. It is a step-by-step approach, in which, for each step different experimental techniques are compared with each others. These can be divided in passive and active spectroscopic methods. It is seen that especially the passive methods for the electron temperature determination are very sensitive to the degree of equilibrium departure suggesting that active spectroscopy is preferable. However, one should realize that lasers can easily heat cool plasmas. This is due to the fact that the ionization degree of CAPs is smalls.

A squared-wave power pulsed low-pressure plasma is investigated by means of Thomson scattering. By this method the values of the electron density and temperature are obtained, directly. The plasma is created by a surfatron launcher in pure argon at gas pressures of 8–70 mbar. Features of the pulse rise and decay are studied with microsecond time resolution. During the pulse rise we observe initial high temperature values, while the density is still rising. At power switch-off we find decay times of the electron density that are smaller than what is expected on the basis of diffusion losses. This implies that the dominant decay mechanism in the studied pressure regime is provided by molecular assisted recombination.

The electron density and electron temperature of a low pressure surface wave sustained argon plasma have been determined using passive and active (laser) spectroscopic methods simultaneously. In this way the validity of the various techniques is established while the plasma properties are determined more precisely. The electron density, ne, is determined with Thomson scattering (TS), absolute continuum measurements, Stark broadening and an extrapolation of the atomic state distribution function (ASDF). The electron temperature, Te, is obtained using TS and absolute line intensity (ALI) measurements combined with a collisional–radiative (CR) model for argon. At an argon pressure of 15 mbar, the ne values obtained with TS and Stark broadening agree with each other within the error bars and are equal to (4 ± 0.5) × 1019 m-3, whereas the ne value (2 ± 0.5) × 1019 m-3 obtained from the continuum is about 30% lower. This suggests that the used formula and cross-section values for the continuum method have to be reconsidered. The electron density determined by means of extrapolation of the ASDF to the continuum is too high (~1020 m-3). This is most probably related to the fact that the plasma is strongly ionizing so that the extrapolation method is not justified. At 15 mbar, the Te values obtained with TS are equal to 13 400 ± 1100 K while the ALI/CR-model yields an electron temperature that is about 10% lower. It can be concluded that the passive results are in good or fair agreement with the active results. Therefore, the calibrated passive methods can be applied to other plasmas in a similar regime for which active diagnostic techniques cannot be used. The electron density and electron temperature of a low pressure surface wave sustained argon plasma have been determined using passive and active (laser) spectroscopic methods simultaneously. In this way the validity of the various techniques is established while the plasma properties are determined more precisely. The electron density, ne, is determined with Thomson scattering (TS), absolute continuum measurements, Stark broadening and an extrapolation of the atomic state distribution function (ASDF). The electron temperature, Te, is obtained using TS and absolute line intensity (ALI) measurements combined with a collisional–radiative (CR) model for argon. At an argon pressure of 15 mbar, the ne values obtained with TS and Stark broadening agree with each other within the error bars and are equal to (4 ± 0.5) × 1019 m-3, whereas the ne value (2 ± 0.5) × 1019 m-3 obtained from the continuum is about 30% lower. This suggests that the used formula and cross-section values for the continuum method have to be reconsidered. The electron density determined by means of extrapolation of the ASDF to the continuum is too high (~1020 m-3). This is most probably related to the fact that the plasma is strongly ionizing so that the extrapolation method is not justified. At 15 mbar, the Te values obtained with TS are equal to 13 400 ± 1100 K while the ALI/CR-model yields an electron temperature that is about 10% lower. It can be concluded that the passive results are in good or fair agreement with the active results. Therefore, the calibrated passive methods can be applied to other plasmas in a similar regime for which active diagnostic techniques cannot be used. The electron density and electron temperature of a low pressure surface wave sustained argon plasma have been determined using passive and active (laser) spectroscopic methods simultaneously. In this way the validity of the various techniques is established while the plasma properties are determined more precisely. The electron density, ne, is determined with Thomson scattering (TS), absolute continuum measurements, Stark broadening and an extrapolation of the atomic state distribution function (ASDF). The electron temperature, Te, is obtained using TS and absolute line intensity (ALI) measurements combined with a collisional–radiative (CR) model for argon. At an argon pressure of 15 mbar, the ne values obtained with TS and Stark broadening agree with each other within the error bars and are equal to (4 ± 0.5) × 1019 m-3, whereas the ne value (2 ± 0.5) × 1019 m-3 obtained from the continuum is about 30% lower. This suggests that the used formula and cross-section values for the continuum method have to be reconsidered. The electron density determined by means of extrapolation of the ASDF to the continuum is too high (~1020 m-3). This is most probably related to the fact that the plasma is strongly ionizing so that the extrapolation method is not justified. At 15 mbar, the Te values obtained with TS are equal to 13 400 ± 1100 K while the ALI/CR-model yields an electron temperature that is about 10% lower. It can be concluded that the passive results are in good or fair agreement with the active results. Therefore, the calibrated passive methods can be applied to other plasmas in a similar regime for which active diagnostic techniques cannot be used.