Teaching old sensors New tricks: archetypes of intelligence

In this paper a generic intelligent sensor software architecture is described which builds upon the basic requirements of related industry standards (IEEE 1451 and SEVA BS- 7986). It incorporates specific functionalities such as real-time fault detection, drift compensation, adaptation to environmental changes and autonomous reconfiguration. The modular based structure of the intelligent sensor architecture provides enhanced flexibility in regard to the choice of specific algorithmic realizations. In this context, the particular aspects of fault detection and drift estimation are discussed. A mixed indicative/corrective fault detection approach is proposed while it is demonstrated that reversible/irreversible state dependent drift can be estimated using generic algorithms such as the EKF or on-line density estimators. Finally, a parsimonious density estimator is presented and validated through simulated and real data for use in an operating regime dependent fault detection framework

Use of the Extended Kalman Filter for State Dependent Drift Estimation in Weakly Nonlinear Sensors

A number of mechanisms are responsible for the generation of reversible or irreversible drift in the response of a sensor. In this letter, we discuss three approaches for the identification of reversible state dependent drift in sensors through the use of the Extended Kalman Filter. We compare their performance by simulation and demonstrate their validity by estimating the drift of an accelerometer, modeled as a weakly nonlinear system

Algorithms for sensor validation and multisensor fusion

Existing techniques for sensor validation and sensor fusion are often based on analytical sensor models. Such models can be arbitrarily complex and consequently Gaussian distributions are often assumed, generally with a detrimental effect on overall system performance. A holistic approach has therefore been adopted in order to develop two novel and complementary approaches to sensor validation and fusion based on empirical data. The first uses the Nadaraya-Watson kernel estimator to provide competitive sensor fusion. The new algorithm is shown to reliably detect and compensate for bias errors, spike errors, hardover faults, drift faults and erratic operation, affecting up to three of the five sensors in the array. The inherent smoothing action of the kernel estimator provides effective noise cancellation and the fused result is more accurate than the single 'best sensor'. A Genetic Algorithm has been used to optimise the Nadaraya-Watson fuser design. The second approach uses analytical redundancy to provide the on-line sensor status output μH∈[0,1], where μH=1 indicates the sensor output is valid and μH=0 when the sensor has failed. This fuzzy measure is derived from change detection parameters based on spectral analysis of the sensor output signal. The validation scheme can reliably detect a wide range of sensor fault conditions. An appropriate context dependent fusion operator can then be used to perform competitive, cooperative or complementary sensor fusion, with a status output from the fuser providing a useful qualitative indication of the status of the sensors used to derive the fused result. The operation of both schemes is illustrated using data obtained from an array of thick film metal oxide pH sensor electrodes. An ideal pH electrode will sense only the activity of hydrogen ions, however the selectivity of the metal oxide device is worse than the conventional glass electrode. The use of sensor fusion can therefore reduce measurement uncertainty by combining readings from multiple pH sensors having complementary responses. The array can be conveniently fabricated by screen printing sensors using different metal oxides onto a single substrate

Anatomy of the bacillus subtilis cell envelope stress response

The bacterial cell wall withstands the turgor pressure and is an essential structure for most bacteria. The lipid II cycle is responsible for transporting cell wall building blocks across the cytoplasmic membrane by means of the carrier molecule undecaprenyl phosphate (UP). One essential step is the recycling of undecaprenyl pyrophosphate (UPP) to UP by UPP phosphatases. This step is targeted by bacitracin, an UPP-binding anti-microbial peptide (AMP). In the course of this thesis, the effect of deletion and depletion of bacitracin resistance modules and UPP phosphatase genes on the cell envelope stress response in Bacillus subtilis was evaluated. The main resistance determinant against bacitracin, the ABC-transporter BceAB was found to be homeostatically regulated “to need” by flux-sensing of its own activity. The full effect of the secondary layer of resistance determinants, consisting of the UPP phosphatase BcrC and the phage shock protein-like response of the Lia-system, is only revealed in the absence of BceAB. For the first time, a resistance phenotype for LiaIH toward bacitracin was reported. The genes uppP and bcrC encode UPP phosphatases and were found to be synthetic lethal. Depletion of either UPP phosphatase in a double mutant background lead to bulging cells in exponential growth phase. BcrC is the main UPP phosphatase during growth. In contrast, UppP is primarily responsible for normal sporulation. The generation of UP in the lipid II cycle is essential and can be impaired by (i) addition of the UPP-binding AMP bacitracin, (ii) deletion and depletion of UPP phosphatases (BcrC and UppP), or, to a limited degree, (iii) deletion of the undecaprenol kinase (UDPK) DgkA. There is a marked difference in the CESR toward these challenges: while the addition of bacitracin activates two damage driven promoters, PliaI and PbcrC, a lack of UPP phosphatases or DgkA is only detected by the latter. This indicates that the blocking of UPP with bacitracin has a different effect on the cell envelope than the shortage of UPP phosphatases. Our analysis of the dephosphorylation of UPP in B. subtilis lays another cornerstone for the holistic understanding of the lipid II cycle.Die bakterielle Zellwand ist für die meisten Bakterien überlebensnotwendig, zum Beispiel um dem Turgor entgegenzuwirken. Sie besteht aus Zucker-Peptidbausteinen, deren Auf- und Abbau komplex reguliert ist. Für die Anlieferung der Bausteine ist der Lipid II-Zyklus mit dem Transportmolekül Undecaprenylphosphat (UP) zuständig. Nach Einbau des Zellwandbausteins liegt das Transportmolekül als Undecaprenylpyrophosphat (UPP) vor und wird von UPP-Phosphatasen zu UP dephosphoryliert, um wiederverwendet werden zu können. An diesem essentiellen Schritt greift das Peptidantibiotikum Bacitracin an, indem es an UPP bindet und so das Recycling verhindert. Eine Blockade des Lipid II-Zyklus führt zu fehlerhafter Zellwandsynthese mit entsprechenden morphologischen Phänotypen, sowie zur Aktivierung der Zellwandstressantwort. In dieser Arbeit wird die Dephosphorylierung von UPP in Bacillus subtilis in zwei Aspekten genetisch untersucht. Zum einen wird unter Bacitracinstress beobachtet, wie die nativen Sensoren und Resistenzmechanismen in Abhängigkeit voneinander reagieren. Zum anderen werden die Auswirkungen eines UPP-Phosphatase-Defizits beleuchtet. Der ABC-Transporter BceAB ist die primäre Resistenzdeterminante gegen Bacitracin. Seine Anzahl wird durch homöostatische Selbstregulierung an den aktuellen Bedarf angepasst, indem die Aktivität der Transporter als Signal für deren Auslastung verwendet wird. Die sekundären Resistenzdeterminanten, die UPP-Phosphatase BcrC und LiaIH (wobei LiaH Ähnlichkeit zum Phagenschockprotein A aufweist), werden schadensabhängig induziert. Ihr volles Potential wird nur in Abwesenheit von BceAB sichtbar. Zum ersten Mal wurde gezeigt, dass LiaIH Resistenz gegen Bacitracin vermitteln kann, obwohl deren Expression bei Bacitracinstress schon seit über zehn Jahren bekannt ist. Außerdem konnte gezeigt werden, dass die Gene bcrC und uppP der UPP-Phosphatasen BcrC und UppP ein essentielles Paar bilden. Die Depletion dieser Phosphatasen in einer bcrC uppP Doppelmutante führte zu gewölbten Zellen in der exponentiellen Wachstumsphase. BcrC stellt die Haupt-UPP-Phosphatase während des Wachstums dar, wohingegen UppP für die ordnungsgemäße Sporulation benötigt wird. Die (Wieder-)Herstellung von UP ist für den Lipid II Zyklus essentiell und kann auf drei Arten gestört werden: (i) Zugabe von Bacitracin, welches UPP bindet und die Dephosphorylierung verhindert, (ii) Deletion und Depletion der UPP-Phosphatasen BcrC und UppP, oder, in geringem Umfang, (iii) Deletion der Undecaprenol-Kinase DgkA. Hierbei zeigt sich ein drastischer Unterschied in der Zellwandstressantwort. Während durch Bacitracin zwei schadensabhängige Promotoren aktiviert werden, PliaI und PbcrC, ist bei UPP-Phosphatase- oder DgkA-Mangel nur letzterer aktiv. Dies deutet darauf hin, dass diese Eingriffe auf die Bildung von UP verschiedene molekulare Konsequenzen haben, die unterschiedlich detektiert werden. Unsere Untersuchung der UPP-Dephosphorylierung legt einen weiteren Grundstein für das umfängliche Verständnis der Funktion und Regulation des Lipid II Zyklus und der Zellwandbiosynthese

Face recognition by means of advanced contributions in machine learning

Face recognition (FR) has been extensively studied, due to both scientific fundamental challenges and current and potential applications where human identification is needed. FR systems have the benefits of their non intrusiveness, low cost of equipments and no useragreement requirements when doing acquisition, among the most important ones. Nevertheless, despite the progress made in last years and the different solutions proposed, FR performance is not yet satisfactory when more demanding conditions are required (different viewpoints, blocked effects, illumination changes, strong lighting states, etc). Particularly, the effect of such non-controlled lighting conditions on face images leads to one of the strongest distortions in facial appearance. This dissertation addresses the problem of FR when dealing with less constrained illumination situations. In order to approach the problem, a new multi-session and multi-spectral face database has been acquired in visible, Near-infrared (NIR) and Thermal infrared (TIR) spectra, under different lighting conditions. A theoretical analysis using information theory to demonstrate the complementarities between different spectral bands have been firstly carried out. The optimal exploitation of the information provided by the set of multispectral images has been subsequently addressed by using multimodal matching score fusion techniques that efficiently synthesize complementary meaningful information among different spectra. Due to peculiarities in thermal images, a specific face segmentation algorithm has been required and developed. In the final proposed system, the Discrete Cosine Transform as dimensionality reduction tool and a fractional distance for matching were used, so that the cost in processing time and memory was significantly reduced. Prior to this classification task, a selection of the relevant frequency bands is proposed in order to optimize the overall system, based on identifying and maximizing independence relations by means of discriminability criteria. The system has been extensively evaluated on the multispectral face database specifically performed for our purpose. On this regard, a new visualization procedure has been suggested in order to combine different bands for establishing valid comparisons and giving statistical information about the significance of the results. This experimental framework has more easily enabled the improvement of robustness against training and testing illumination mismatch. Additionally, focusing problem in thermal spectrum has been also addressed, firstly, for the more general case of the thermal images (or thermograms), and then for the case of facialthermograms from both theoretical and practical point of view. In order to analyze the quality of such facial thermograms degraded by blurring, an appropriate algorithm has been successfully developed. Experimental results strongly support the proposed multispectral facial image fusion, achieving very high performance in several conditions. These results represent a new advance in providing a robust matching across changes in illumination, further inspiring highly accurate FR approaches in practical scenarios.El reconeixement facial (FR) ha estat àmpliament estudiat, degut tant als reptes fonamentals científics que suposa com a les aplicacions actuals i futures on requereix la identificació de les persones. Els sistemes de reconeixement facial tenen els avantatges de ser no intrusius,presentar un baix cost dels equips d’adquisició i no la no necessitat d’autorització per part de l’individu a l’hora de realitzar l'adquisició, entre les més importants. De totes maneres i malgrat els avenços aconseguits en els darrers anys i les diferents solucions proposades, el rendiment del FR encara no resulta satisfactori quan es requereixen condicions més exigents (diferents punts de vista, efectes de bloqueig, canvis en la il·luminació, condicions de llum extremes, etc.). Concretament, l'efecte d'aquestes variacions no controlades en les condicions d'il·luminació sobre les imatges facials condueix a una de les distorsions més accentuades sobre l'aparença facial. Aquesta tesi aborda el problema del FR en condicions d'il·luminació menys restringides. Per tal d'abordar el problema, hem adquirit una nova base de dades de cara multisessió i multiespectral en l'espectre infraroig visible, infraroig proper (NIR) i tèrmic (TIR), sota diferents condicions d'il·luminació. En primer lloc s'ha dut a terme una anàlisi teòrica utilitzant la teoria de la informació per demostrar la complementarietat entre les diferents bandes espectrals objecte d’estudi. L'òptim aprofitament de la informació proporcionada pel conjunt d'imatges multiespectrals s'ha abordat posteriorment mitjançant l'ús de tècniques de fusió de puntuació multimodals, capaces de sintetitzar de manera eficient el conjunt d’informació significativa complementària entre els diferents espectres. A causa de les característiques particulars de les imatges tèrmiques, s’ha requerit del desenvolupament d’un algorisme específic per la segmentació de les mateixes. En el sistema proposat final, s’ha utilitzat com a eina de reducció de la dimensionalitat de les imatges, la Transformada del Cosinus Discreta i una distància fraccional per realitzar les tasques de classificació de manera que el cost en temps de processament i de memòria es va reduir de forma significa. Prèviament a aquesta tasca de classificació, es proposa una selecció de les bandes de freqüències més rellevants, basat en la identificació i la maximització de les relacions d'independència per mitjà de criteris discriminabilitat, per tal d'optimitzar el conjunt del sistema. El sistema ha estat àmpliament avaluat sobre la base de dades de cara multiespectral, desenvolupada pel nostre propòsit. En aquest sentit s'ha suggerit l’ús d’un nou procediment de visualització per combinar diferents bandes per poder establir comparacions vàlides i donar informació estadística sobre el significat dels resultats. Aquest marc experimental ha permès més fàcilment la millora de la robustesa quan les condicions d’il·luminació eren diferents entre els processos d’entrament i test. De forma complementària, s’ha tractat la problemàtica de l’enfocament de les imatges en l'espectre tèrmic, en primer lloc, pel cas general de les imatges tèrmiques (o termogrames) i posteriorment pel cas concret dels termogrames facials, des dels punt de vista tant teòric com pràctic. En aquest sentit i per tal d'analitzar la qualitat d’aquests termogrames facials degradats per efectes de desenfocament, s'ha desenvolupat un últim algorisme. Els resultats experimentals recolzen fermament que la fusió d'imatges facials multiespectrals proposada assoleix un rendiment molt alt en diverses condicions d’il·luminació. Aquests resultats representen un nou avenç en l’aportació de solucions robustes quan es contemplen canvis en la il·luminació, i esperen poder inspirar a futures implementacions de sistemes de reconeixement facial precisos en escenaris no controlats.Postprint (published version

Binary Galaxies in the Local Supercluster and Its Neighborhood

We report a catalog of 509 pairs identified among 10403 nearby galaxies with line-of-sight velocities V_LG < 3500 km/s.We selected binary systems in accordance with two criteria (bounding and temporal), which require the physical pair of galaxies to have negative total energy and its components to be located inside the zero-velocity surface. We assume that individual galaxy masses are proportional to their total K-band luminosities, M = L_K x 6M/L. The catalog gives the magnitudes and morphological types of galaxies and also the projected (orbital) masses and pair isolation indices. The component line-of-sight velocity differences and projected distances of the binary systems considered have power-law distributions with the median values of 35 km/s and 123 kpc, respectively. The median mass-to-K-band luminosity ratio is equal to 11 M/L, and its uncertainty is mostly due to the errors of measured velocities. Our sample of binary systems has a typical density contrast of d ro/ro_c ~ 500 and a median crossing time of about 3.5 Gyr. We point out the substantial fraction of binary systems consisting of late-type dwarf galaxies, where the luminosities of both components are lower than that of the Small Magellanic Cloud. The median projected distance for 41 such pairs is only 30 kpc, and the median difference of their line-of-sight velocities is equal to 14 km/s which is smaller than the typical error for radial-velocity (30 km/s). This specific population of gas-rich dwarf binary galaxies such as I Zw 18 may be at the stage immediately before merging of its components. Such objects, which are usually lost in flux-limited (and not distance-limited) samples deserve a thorough study in the HI radio line with high spatial and velocity resolution.Comment: published in Astrophysical Bulletin, 2008, Vol. 63, No. 4, pp. 299-34

Absolute protein quantification using fluorescence measurements with FPCountR

This paper presents a generalisable method for the calibration of fluorescence readings on microplate readers, in order to convert arbitrary fluorescence units into absolute units. FPCountR relies on the generation of bespoke fluorescent protein (FP) calibrants, assays to determine protein concentration and activity, and a corresponding analytical workflow. We systematically characterise the assay protocols for accuracy, sensitivity and simplicity, and describe an ‘ECmax’ assay that outperforms the others and even enables accurate calibration without requiring the purification of FPs. To obtain cellular protein concentrations, we consider methods for the conversion of optical density to either cell counts or alternatively to cell volumes, as well as examining how cells can interfere with protein counting via fluorescence quenching, which we quantify and correct for the first time. Calibration across different instruments, disparate filter sets and mismatched gains is demonstrated to yield equivalent results. It also reveals that mCherry absorption at 600 nm does not confound cell density measurements unless expressed to over 100,000 proteins per cell. FPCountR is presented as pair of open access tools (protocol and R package) to enable the community to use this method, and ultimately to facilitate the quantitative characterisation of synthetic microbial circuits

Оценка точности измерения термопреобразователей сопротивления в процессе работы

The creation of specialized measurement tools for deep integration into modern digital process control systems is became possible only when using microprocessor devices in measuring converters. However, today the improvement of the main characteristics of measuring instruments in modern systems of automatic control systems through the use of microprocessors is largely exhausted with a significant margin of performance of the latter. Therefore, it is now an urgent task for the further improvement of means of measurements is to search for new variants of creation of intellectual means of measurement.Within the framework of this task, the functional schemes of intelligent temperature measuring transducers are studied in the article and the algorithms for assessing their metrological serviceability in the process of operation in modern ACS are proposed. Proposed, justified and tested on the experiment an algorithm for evaluating the accuracy of the measurement of thermocouple resistance in the process.Создание специализированных средств измерения для глубокой интеграции в современные цифровые АСУ ТП стало возможным только при использовании в измерительных преобразователях микропроцессорных устройств. Однако на сегодня улучшение основных характеристик средств измерения в современных системах АСУ ТП за счёт применения микропроцессоров в значительной степени исчерпано при существенном запасе производительности последних. Поэтому именно сейчас актуальной задачей дальнейшего совершенствования средств измерений является поиск новых вариантов создания интеллектуальных средств измерения.В рамках этой задачи в статье исследованы функциональные схемы интеллектуальных измерительных преобразователей температуры и предложены алгоритмы оценки их метрологической исправности в процессе работы в современных АСУ ТП. Предложен, обоснован и проверен на эксперименте алгоритм оценки точности измерения термопреобразователя сопротивлений в процессе работы

Validation Techniques for Sensor Data in Mobile Health Applications

Mobile applications have become a must in every user&apos;s smart device, and many of these applications make use of the device sensors&apos; to achieve its goal. Nevertheless, it remains fairly unknown to the user to which extent the data the applications use can be relied upon and, therefore, to which extent the output of a given application is trustworthy or not. To help developers and researchers and to provide a common ground of data validation algorithms and techniques, this paper presents a review of the most commonly used data validation algorithms, along with its usage scenarios, and proposes a classification for these algorithms. This paper also discusses the process of achieving statistical significance and trust for the desired output