Fault Diagnosis for Complex Systems Using Coloured Petri Nets

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Estudio del estado ecológico de los ríos de la cuenca hidrográfica del Júcar (España) mediante el índice BMWP'

El diseño de la Red Biológica, basado en el uso de indicadores hidromorfológicos, físico-químicos y biológicos, permitió realizar un diagnóstico de calidad en 221 puntos de muestreo en 104 ríos de la red hidrográfica del Júcar (Júcar, Turia, Mijares, Vinalopó, Palancia, Serpis y cuencas menores) durante el año 2000 y establecer su estado ecológico. En este trabajo se presentan los resultados obtenidos con el índice BMWP'. Los ríos con un estado ecológico muy bueno se hallan situados en los tramos altos, tanto de los ríos principales como de los afluentes de primer y segundo orden. La mayoría de los puntos de referencia (12.7%) se encuentran en altitudes superiores a los 800 m. Los ríos situados en altitudes medias (800-200 m) se hallan muy regulados y presentan, en general, un estado entre bueno y aceptable, existiendo pocos puntos de referencia (6.8%). Por último, los ríos situados en tierras bajas (< 200 m) se encuentran, la gran mayoría, en un estado deficiente o malo, siendo muy difícil hallar ríos en buen estado y casi imposible establecer puntos de referencia con un muy buen estado ecológico (0.5%). Las medidas correctoras propuestas para los ríos de la red hidrográfica del Júcar se centran en la mejora de las características hidromorfológicas y físico-químicas, y por tanto de las comunidades biológicas, con el propósito final de conseguir el mejor estado ecológico y químico posible para las aguas superficiales tal y como exige la DMA (Directiva Marco del Agua).The design of the Biological Network, based on the use of hydromorphological, physical, chemical, and biological indicators, allowed a diagnosis of the quality in 221 sampling points in 104 rivers of Júcar's Basin (Jucar, Turia, Mijares, Vinalopo, Palancia, Serpis and small basins) to be carried out during the year 2000 and to establish its ecological status. In this work the results obtained with the BMWP' index are presented. The rivers with a high ecological status are located in the high altitudes, so much of the main rivers as of the tributaries of first and second order. Most of the reference points (12.7%) are located at altitudes higher than 800 m. The rivers located at middle-altitudes (800-200 m) are very regulated and they present, in general, an ecological status between good and acceptable, with few reference points (6.8%). Last, the rivers located in lowlands (< 200 m) are, mostly, in a poor or bad ecological state, making it very difficult to find rivers in good ecological status and almost impossible to establish reference points with a high ecological status (0.5%). The correcting measures proposed for the rivers of the Júcar's Basin are centered in the improvement of the hydromorphological, physical, and chemical characteristics, and therefore of the biological communities, with the final purpose of achieving the highest ecological and chemical status possible for surface waters like the WFD (Water Framework Directive) demands

Herbivory on the pedunculate oak along an urbanization gradient in Europe: Effects of impervious surface, local tree cover, and insect feeding guild

Research ArticleUrbanization is an important driver of the diversity and abundance of tree-associated insect herbivores, but its consequences for insect herbivory are poorly understood. A likely source of variability among studies is the insufficient consideration of intra-urban variability in forest cover. With the help of citizen scientists, we investigated the independent and interactive effects of local canopy cover and percentage of impervious surface on insect herbivory in the pedunculate oak (Quercus robur L.) throughout most of its geographic range in Europe. We found that the damage caused by chewing insect herbivores as well as the incidence of leaf-mining and gall-inducing herbivores consistently decreased with increasing impervious surface around focal oaks. Herbivory by chewing herbivores increased with increasing forest cover, regardless of impervious surface. In contrast, an increase in local canopy cover buffered the negative effect of impervious surface on leaf miners and strengthened its effect on gall inducers. These results show that—just like in non-urban areas—plant– herbivore interactions in cities are structured by a complex set of interacting factors. This highlights that local habitat characteristics within cities have the potential to attenuate or modify the effect of impervious surfaces on biotic interactionsinfo:eu-repo/semantics/publishedVersio

The Challenge of Detection and Diagnosis of Fugacious Hardware Faults in VLSI Designs

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-38789-0_7Current integration scales are increasing the number and types of faults that embedded systems must face. Traditional approaches focus on dealing with those transient and permanent faults that impact the state or output of systems, whereas little research has targeted those faults being logically, electrically or temporally masked -which we have named fugacious. A fast detection and precise diagnosis of faults occurrence, even if the provided service is unaffected, could be of invaluable help to determine, for instance, that systems are currently under the influence of environmental disturbances like radiation, suffering from wear-out, or being affected by an intermittent fault. Upon detection, systems may react to adapt the deployed fault tolerance mechanisms to the diagnosed problem. This paper explores these ideas evaluating challenges and requirements involved, and provides an outline of potential techniques to be applied.This work has been funded by Spanish Ministry of Economy ARENES project (TIN2012-38308-C02-01)Espinosa García, J.; Andrés Martínez, DD.; Ruiz, JC.; Gil, P. (2013). The Challenge of Detection and Diagnosis of Fugacious Hardware Faults in VLSI Designs. En Dependable Computing. Springer. 76-87. https://doi.org/10.1007/978-3-642-38789-0_7S7687Narayanan, V., Xie, Y.: Reliability concerns in embedded systems design. IEEE Computer 1(39), 118–120 (2006)Hannius, O., Karlsson, J.: Impact of soft errors in a jet engine controller. In: Ortmeier, F., Daniel, P. (eds.) SAFECOMP 2012. LNCS, vol. 7612, pp. 223–234. Springer, Heidelberg (2012)Borkar, S.: Designing reliable systems from unreliable components: the challenges of transistor variability and degradation. IEEE Micro 25(6), 10–16 (2005)JEDEC: Measurement and reporting of alpha particle and terrestrial cosmic ray-induced soft errors in semiconductor devices. JEDEC Standard JESD89A. JEDEC (2006)Gracia-Moran, J., Gil-Tomas, D., Saiz-Adalid, L.J., Baraza, J.C., Gil-Vicente, P.J.: Experimental validation of a fault tolerant microcomputer system against intermittent faults. In: DSN, pp. 413–418 (2010)Constantinescu, C.: Intermittent faults and effects on reliability of integrated circuits. In: Proceedings of the 2008 Annual Reliability and Maintainability Symposium, pp. 370–374. IEEE Computer Society, Washington, DC (2008)Avizienis, A., Laprie, J.C., Randell, B., Landwehr, C.: Basic concepts and taxonomy of dependable and secure computing. IEEE Trans. Dependable Secur. Comput. 1, 11–33 (2004)Johnson, C., Holloway, C.: The dangers of failure masking in fault-tolerant software: Aspects of a recent in-flight upset event. In: 2007 2nd Institution of Engineering and Technology International Conference on System Safety, pp. 60–65 (October 2007)Bolchini, C., Salice, F., Sciuto, D.: Fault analysis for networks with concurrent error detection. IEEE Des. Test 15(4), 66–74 (1998)Goessel, M., Ocheretny, V., Sogomonyan, E., Marienfeld, D.: New Methods of Concurrent Checking (Frontiers in Electronic Testing), 1st edn. Springer Publishing Company, Incorporated (2008)Iyer, R.K., Rossetti, D.J.: A statistical load dependency model for cpu errors at slac. In: Twenty-Fifth International Symposium on Fault-Tolerant Computing, ‘Highlights from Twenty-Five Years’, p. 373 (June 1995)Dodd, P.E., Shaneyfelt, M.R., Felix, J.A., Schwank, J.R.: Production and propagation of single-event transients in high-speed digital logic ics. IEEE Transactions on Nuclear Science 51, 3278–3284 (2004)Nightingale, E.B., Douceur, J.R., Orgovan, V.: Cycles, cells and platters: an empirical analysisof hardware failures on a million consumer pcs. In: Proceedings of the Sixth Conference on Computer Systems, EuroSys 2011, pp. 343–356. ACM, New York (2011)Kimseng, K., Hoit, M., Tiwari, N., Pecht, M.: Physics-of-failure assessment of a cruise control module. Microelectronics Reliability 39(10), 1423–1444 (1999)Savir, J.: Detection of single intermittent faults in sequential circuits. IEEE Trans. Comput. 29(7), 673–678 (1980)Correcher, A., Garcia, E., Morant, F., Quiles, E., Rodriguez, L.: Intermittent failure dynamics characterization. IEEE Transactions on Reliability 61(3), 649–658 (2012)Sorensen, B., Kelly, G., Sajecki, A., Sorensen, P.: An analyzer for detecting intermittent faults in electronic devices. In: AUTOTESTCON 1994. IEEE Systems Readiness Technology Conference. ‘Cost Effective Support Into the Next Century’, Conference Proceedings, pp. 417–421 (September 1994)Sosnowski, J.: Transient fault tolerance in digital systems. IEEE Micro 14(1), 24–35 (1994)Bondavalli, A., Chiaradonna, S., Di Giandomenico, F., Grandoni, F.: Threshold-based mechanisms to discriminate transient from intermittent faults. IEEE Trans. Comput. 49(3), 230–245 (2000)Rashid, L., Pattabiraman, K., Gopalakrishnan, S.: Intermittent hardware errors and recovery: modelling and evaluation. In: International Conference on Quantitative Evaluation of Systems, QEST (2012)Touba, N.A., McCluskey, E.J.: Logic synthesis of multilevel circuits with concurrent error detection. IEEE Trans. CAD 16(7), 783–789 (1997)Nicolaidis, M., Manich, S., Figueras, J.: Achieving fault secureness in parity prediction arithmetic operators: General conditions and implementations. In: Proceedings of the 1996 European conference on Design and Test, EDTC 1996, pp. 186–193. IEEE Computer Society, Washington, DC (1996)Ko, S.B., Lo, J.C.: Efficient realization of parity prediction functions in fpgas. J. Electron. Test. 20(5), 489–499 (2004)D’Angelo, S., Sechi, G.R., Metra, C.: Transient and permanent fault diagnosis for fpga-based tmr systems. In: Proceedings of the 14th International Symposium on Defect and Fault-Tolerance in VLSI Systems, DFT 1999, pp. 330–338. IEEE Computer Society, Washington, DC (1999)Kim, C.: Detection and location of intermittent faults by monitoring carrier signal channel behavior of electrical interconnection system. In: Electric Ship Technologies Symposium, ESTS 2009, pp. 449–455. IEEE (April 2009

Implementation and analysis of list mode algorithm using tubes of response on a dedicated brain and breast PET

In this work we present an innovative algorithm for the reconstruction of PET images based on the List-Mode (LM) technique which improves their spatial resolution compared to results obtained with current MLEM algorithms. This study appears as a part of a large project with the aim of improving diagnosis in early Alzheimer disease stages by means of a newly developed hybrid PET-MR insert. At the present, Alzheimer is the most relevant neurodegenerative disease and the best way to apply an effective treatment is its early diagnosis. The PET device will consist of several monolithic LYSO crystals coupled to SiPM detectors. Monolithic crystals can reduce scanner costs with the advantage to enable implementation of very small virtual pixels in their geometry. This is especially useful for LM reconstruction algorithms, since they do not need a pre-calculated system matrix. We have developed an LM algorithm which has been initially tested with a large aperture (186 mm) breast PET system. Such an algorithm instead of using the common lines of response, incorporates a novel calculation of tubes of response. The new approach improves the volumetric spatial resolution about a factor 2 at the border of the field of view when compared with traditionally used MLEM algorithm. Moreover, it has also shown to decrease the image noise, thus increasing the image quality. © 2012 Elsevier B.V. All rights reserved.This work was supported by the Centre for Industrial Technological Development co-funded by FEDER through the Technology Fund (DREAM Project, IDI-20110718), by the Spanish Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica (I+D+I) under Grant. No. FIS2010-21216-CO2-01TEO 2008/114.Moliner Martínez, L.; Correcher, C.; González Martínez, AJ.; Conde Castellanos, PE.; Hernández Hernández, L.; Orero Palomares, A.; Rodríguez Álvarez, MJ.... (2013). Implementation and analysis of list mode algorithm using tubes of response on a dedicated brain and breast PET. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 702:129-132. https://doi.org/10.1016/j.nima.2012.08.029S12913270

Low-Dose Imaging in a New Preclinical Total-Body PET/CT Scanner.

Ionizing radiation constitutes a health risk to imaging scientists and study animals. Both PET and CT produce ionizing radiation. CT doses in pre-clinical in vivo imaging typically range from 50 to 1,000 mGy and biological effects in mice at this dose range have been previously described. [ <sup>18</sup> F]FDG body doses in mice have been estimated to be in the range of 100 mGy for [ <sup>18</sup> F]FDG. Yearly, the average whole body doses due to handling of activity by PET technologists are reported to be 3-8 mSv. A preclinical PET/CT system is presented with design features which make it suitable for small animal low-dose imaging. The CT subsystem uses a X-source power that is optimized for small animal imaging. The system design incorporates a spatial beam shaper coupled with a highly sensitive flat-panel detector and very fast acquisition (<10 s) which allows for whole body scans with doses as low as 3 mGy. The mouse total-body PET subsystem uses a detector architecture based on continuous crystals, coupled to SiPM arrays and a readout based in rows and columns. The PET field of view is 150 mm axial and 80 mm transaxial. The high solid-angle coverage of the sample and the use of continuous crystals achieve a sensitivity of 9% (NEMA) that can be leveraged for use of low tracer doses and/or performing rapid scans. The low-dose imaging capabilities of the total-body PET subsystem were tested with NEMA phantoms, in tumor models, a mouse bone metabolism scan and a rat heart dynamic scan. The CT imaging capabilities were tested in mice and in a low contrast phantom. The PET low-dose phantom and animal experiments provide evidence that image quality suitable for preclinical PET studies is achieved. Furthermore, CT image contrast using low dose scan settings was suitable as a reference for PET scans. Total-body mouse PET/CT studies could be completed with total doses of <10 mGy

Uncertainty on radiation doses estimated by biological and retrospective physical methods

Biological and physical retrospective dosimetry are recognised as key techniques to provide individual estimates of dose following unplanned exposures to ionising radiation. Whilst there has been a relatively large amount of recent development in the biological and physical procedures, development of statistical analysis techniques has failed to keep pace. The aim of this paper is to review the current state of the art in uncertainty analysis techniques across the ‘EURADOS Working Group 10— Retrospective dosimetry’ members, to give concrete examples of implementation of the techniques recommended in the international standards, and to further promote the use of Monte Carlo techniques to support characterisation of uncertainties. It is concluded that sufficient techniques are available and in use by most laboratories for acute, whole body exposures to highly penetrating radiation, but further work will be required to ensure that statistical analysis is always wholly sufficient for the more complex exposure scenarios