Testing Based on Identifiable P Systems Using Cover Automata and X-Machines

YesThis paper represents a significant advance on the issue of testing for implementations specified by P systems with transformation and communicating rules. Using the X-machine framework and the concept of cover automaton, it devises a testing approach for such systems, that, under well defined conditions, it ensures that the implementation conforms to the specification. It also investigates the issue of identifiability for P systems, that is an essential prerequisite for testing implementations based on such specifications and establishes a fundamental set of properties for identifiable P systems.Marian Gheorghe and Savas Konur acknowledge the support from EPSRC (EP/I031812/1). Marian Gheorghe’s and Florentin Ipate’s work is partially supported by CNCS-UEFISCDI (PN-II-ID-PCE-2011-3-0688)

Counting Membrane Systems

A decision problem is one that has a yes/no answer, while a counting problem asks how many possible solutions exist associated with each instance. Every decision problem X has associated a counting problem, denoted by #X, in a natural way by replacing the question “is there a solution?” with “how many solutions are there?”. Counting problems are very attractive from a computational complexity point of view: if X is an NP-complete problem then the counting version #X is NP-hard, but the counting version of some problems in class P can also be NP-hard. In this paper, a new class of membrane systems is presented in order to provide a natural framework to solve counting problems. The class is inspired by a special kind of non-deterministic Turing machines, called counting Turing machines, introduced by L. Valiant. A polynomial-time and uniform solution to the counting version of the SAT problem (a well-known #P-complete problem) is also provided, by using a family of counting polarizationless P systems with active membranes, without dissolution rules and division rules for non-elementary membranes but where only very restrictive cooperation (minimal cooperation and minimal production) in object evolution rules is allowed

Risks of Chest X-ray Examination for Students

Chest X-ray (CXR) examination is considered essential for health checkups of students;thus, it is important to objectively assess the CXR for a better understanding of the appropriate X-ray exposure dose, and the risks such an examination entails. Accordingly, we performed a multi-institutional study regarding students' CXR exposure, during a 6year-period from 2002 (partially including 2001) to 2007, with the collaboration of national, municipal, and private universities and colleges in Japan. A glass badge was worn by the students at the time of CXR screening examination. These glass badges were collected, and their X-ray exposure doses were measured. The results indicated a tendency of decreasing exposure dose over the 6 years, though the difference was not significant. In a comparison of the chest X-ray systems within institutions (own X-ray equipmentinside systems) with those outside the institution (mobile X-ray equipmentoutside systems), the average exposure dose with the outside systems exceeded that of the inside systems. Both inside and outside systems included a few X-ray machines with which the exposure was more than 1mSv. Based on these facts, individuals in charge of student health checkups should be aware of the exposure dose of each chest fluorographic system at their institution.</p

Software platform virtualization in chemistry research and university teaching

<p>Abstract</p> <p>Background</p> <p>Modern chemistry laboratories operate with a wide range of software applications under different operating systems, such as Windows, LINUX or Mac OS X. Instead of installing software on different computers it is possible to install those applications on a single computer using Virtual Machine software. Software platform virtualization allows a single guest operating system to execute multiple other operating systems on the same computer. We apply and discuss the use of virtual machines in chemistry research and teaching laboratories.</p> <p>Results</p> <p>Virtual machines are commonly used for cheminformatics software development and testing. Benchmarking multiple chemistry software packages we have confirmed that the computational speed penalty for using virtual machines is low and around 5% to 10%. Software virtualization in a teaching environment allows faster deployment and easy use of commercial and open source software in hands-on computer teaching labs.</p> <p>Conclusion</p> <p>Software virtualization in chemistry, mass spectrometry and cheminformatics is needed for software testing and development of software for different operating systems. In order to obtain maximum performance the virtualization software should be multi-core enabled and allow the use of multiprocessor configurations in the virtual machine environment. Server consolidation, by running multiple tasks and operating systems on a single physical machine, can lead to lower maintenance and hardware costs especially in small research labs. The use of virtual machines can prevent software virus infections and security breaches when used as a sandbox system for internet access and software testing. Complex software setups can be created with virtual machines and are easily deployed later to multiple computers for hands-on teaching classes. We discuss the popularity of bioinformatics compared to cheminformatics as well as the missing cheminformatics education at universities worldwide.</p

Skew-Gaussian model of small-photon-number coherent Ising machines

A Gaussian quantum theory of bosonic modes has been widely used to describe quantum optical systems, including coherent Ising machines (CIMs) that consist of $\chi^{(2)}$ degenerate optical parametric oscillators (DOPOs) as nonlinear elements. However, Gaussian models have been thought to be invalid in the extremely strong-gain-saturation limit. Here, we develop an extended Gaussian model including two third-order fluctuation products, $\langle \delta \hat{X}^3\rangle$ and $\langle \delta \hat{X}\delta \hat{P}^2\rangle$, which we call self-skewness and cross-skewness, respectively. This new model which we call skew-Gaussian model more precisely replicates the success probability predicted by the quantum master equation (QME), relative to Gaussian models. We also discuss the impact of skew variables on the performance of CIMs

A model learning based testing approach for kernel P systems

YesKernel P systems have been introduced as a unifying formalism allowing to specify, simulate and analyse various problems. Several applications of this model have been considered and a powerful tool built in order to support their development and analysis. Testing represents an important aspect of any system analysis and correctness. In this paper we introduce for the first time a bounded test generation approach for kernel P systems by considering bounded input sequences. A learning algorithm for kernel P systems is based on learning X-machine models that are equivalent to these systems for sequences of steps up to a certain limit, ℓ. The Lℓ learning algorithm is used. The testing approach is then devised from the inferred X-machines. The method is applied to a case study illustrating the key parts of the approach.This research was supported by the European Regional Development Fund, Competitiveness Operational Program 2014-2020 through project IDBC (code SMIS 2014+: 121512). Raluca Lefticaru, Savas Konur and Marian Gheorghe have been partially supported by the Royal Society grant IES╲R3╲213176, 2022-2024. The work of Savas Konur is also supported by EPSRC (EP/R043787/1)

Higher-order spectral analysis of stray flux signals for faults detection in induction motors

[EN] This work is a review of current trends in the stray flux signal processing techniques applied to the diagnosis of electrical machines. Initially, a review of the most commonly used standard methods is performed in the diagnosis of failures in induction machines and using stray flux; and then specifically it is treated and performed the algorithms based on statistical analysis using cumulants and polyspectra. In addition, the theoretical foundations of the analyzed algorithms and examples applications are shown from the practical point of view where the benefits that processing can have using HOSA and its relationship with stray flux signal analysis, are illustrated.This work has been supported by Generalitat Valenciana, Conselleria d'Educació, Cultura i Esport in the framework of the "Programa para la promoción de la investigación científica, el desarrollo tecnológico y la innovación en la Comunitat Valenciana", Subvenciones para grupos de investigación consolidables (ref: AICO/2019/224). J. Alberto Conejero is also partially supported by MEC Project MTM2016-75963-P.Iglesias Martínez, ME.; Antonino Daviu, JA.; Fernández De Córdoba, P.; Conejero, JA. (2020). Higher-order spectral analysis of stray flux signals for faults detection in induction motors. Applied Mathematics and Nonlinear Sciences. 5(2):1-14. https://doi.org/10.2478/amns.2020.1.00032S11452H. Akçay and E. Germen. 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Autoencoding the Retrieval Relevance of Medical Images

Content-based image retrieval (CBIR) of medical images is a crucial task that can contribute to a more reliable diagnosis if applied to big data. Recent advances in feature extraction and classification have enormously improved CBIR results for digital images. However, considering the increasing accessibility of big data in medical imaging, we are still in need of reducing both memory requirements and computational expenses of image retrieval systems. This work proposes to exclude the features of image blocks that exhibit a low encoding error when learned by a $n/p/n$ autoencoder ($p\!<\!n$). We examine the histogram of autoendcoding errors of image blocks for each image class to facilitate the decision which image regions, or roughly what percentage of an image perhaps, shall be declared relevant for the retrieval task. This leads to reduction of feature dimensionality and speeds up the retrieval process. To validate the proposed scheme, we employ local binary patterns (LBP) and support vector machines (SVM) which are both well-established approaches in CBIR research community. As well, we use IRMA dataset with 14,410 x-ray images as test data. The results show that the dimensionality of annotated feature vectors can be reduced by up to 50% resulting in speedups greater than 27% at expense of less than 1% decrease in the accuracy of retrieval when validating the precision and recall of the top 20 hits.Comment: To appear in proceedings of The 5th International Conference on Image Processing Theory, Tools and Applications (IPTA'15), Nov 10-13, 2015, Orleans, Franc

Induction machine model with space harmonics for the diagnosis of rotor eccentricity, based on the convolution theorem

[EN] Condition based maintenance (CBM) systems of induction machines (IMs) require fast and accurate models that can reproduce the fault related harmonics generated by different kinds of faults. Such models are needed to develop new diagnostic algorithms for detecting the faults at an early stage, to analyse the physical interactions between simultaneous faults of different types, or to train expert systems that can supervise and identify these faults in an autonomous way. To achieve these goals, these models must take into account the space harmonics of the air gap magnetomotive force (MMF) generated by the machine windings under fault conditions, due to the complex interactions between spatial and time harmonics in a faulty machine. One of the most common faults in induction machines is the rotor eccentricity, which can cause significant radial forces and, in extreme cases, produce destructive rotor-stator rub. However, the development of a fast, analytical model of the eccentric IM is a challenging task, due to the non-uniformity of the air gap. In this paper, a new method is proposed to obtain such a fast model. This method, which is theoretically justified, first enables a fast calculation of the self and mutual inductances of the stator and rotor phases for every rotor position, taking into account the non-uniform air-gap length and the actual position of all the stator and rotor conductors. Once these inductances are calculated, they are used in a coupled circuits analytical model of the IM, which in this way is able to calculate the time evolution of the electrical and mechanical quantities that characterize the machine functioning, under any type of eccentricity. Specifically, the model is able to reproduce accurately the characteristic eccentricity fault related harmonics in the spectrum of the stator current. The proposed approach is validated through two different methods. First, using a finite elements (FEM) model, in order to validate the correctness of the proposed method for calculating self and mutual inductances, taking into account the non-uniform air-gap. Finally, through an experimental test-bed using a commercial induction motor with a forced mixed eccentricity fault, in order to validate that the full model correctly reproduces the phase currents in such a way that their spectra accurately show the harmonics related with the eccentricity fault, which are the basis of many MCSA diagnostic approaches.This work was supported by the Spanish "Ministerio de Ciencia, Innovacion y Universidades (MCIU)", the "Agenda Estatal de Investigacion (AEI)" and the "Fondo Europeo de Desarrollo Regional (FEDER)" in the framework of the "Proyectos I + D + i - Retos Investigacion 2018", project reference RTI2018-102175-13400 (MCIU/AEI/FEDER, UE).Sapena-Bano, A.; Martinez-Roman, J.; Puche-Panadero, R.; Pineda Sánchez, M.; Pérez-Cruz, J.; Riera-Guasp, M. (2020). 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Signature Analysis for Online Motor Diagnostics: Early Detection of Rotating Machine Problems Prior to Failure. IEEE Industry Applications Magazine, 23(4), 76-81. doi:10.1109/mias.2016.2600684Manohar, M., Koley, E., & Ghosh, S. (2019). Enhancing resilience of PV-fed microgrid by improved relaying and differentiating between inverter faults and distribution line faults. International Journal of Electrical Power & Energy Systems, 108, 271-279. doi:10.1016/j.ijepes.2019.01.015Xia, X., Zhou, J., Li, C., & Zhu, W. (2015). A novel method for fault diagnosis of hydro generator based on NOFRFs. International Journal of Electrical Power & Energy Systems, 71, 60-67. doi:10.1016/j.ijepes.2015.02.022Zhao, B., Yang, M., Diao, H. R., An, B., Zhao, Y. C., & Zhang, Y. M. (2019). A novel approach to transformer fault diagnosis using IDM and naive credal classifier. 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Design of a high-speed-force-stroke thermomechanical micro-actuator via geometric contouring and mechanical frequency multiplication

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 187-192).The aims of this research were to understand (1) why marked performance improvements are observed when one contours the geometry of micro-thermomechanical actuators (pTMAs), (2) how to parametrically model and optimize these improvements, (3) how to use transient electrical command signals to augment these improvements, and (4) how to design arrayed pairs of actuator teams that enable the realization of these improvements within small-scale precision machines. This work has extended the performance envelope of small-scale electromechanical systems to cover the needs of emerging positioning applications that were previously impractical. The results are important to, for example, small-scale machines that are increasingly needed within biological imaging equipment, equipment for nanomanufacturing, and instruments for nano-scale research. These positioning systems must be of small geometric scale in order to achieve viable bandwidth (kHz), resolution (nanometers), cost ($10s/device) and stability (A/min) levels. Miniaturized machines require small-scale actuators, but unfortunately, state-of-the-art actuators are not capable of simultaneously satisfying the force (~10OmN), stroke (~100pLm) and bandwidth (-lkHz) requirements of the preceding applications. In the absence of a practical actuation technology, many small-scale devices were relegated to "demo" status, and they never realized the full promise that small-scale machines could deliver for the preceding applications. This work has generated two concepts - geometric contouring and mechanical frequency multiplication that make jtTMAs behave in a manner that is very different from how they have acted in the past: (1) Geometric contouring:(cont) The variation of a beam's cross-sectional area along its length to achieve more favorable thermal characteristics, i.e. temperature profile, while simultaneously reducing the elastic energy storage within the beam, and (2) Mechanical frequency multiplication: The use of pTMAs pairs that cooperate to reduce their combined cycle time below their individual cycle times, thereby increasing their operating frequency. The utility and practical implementation of these techniques were illustrated via a case study on a threeaxis optical scanner for a two-photon endomicroscope. The device consisted of three sub-systems: (i) an optical system (prism, graded index lens, and optical fiber) that was used to deliver/collect photons during imaging, (ii) a small-scale electromechanical scanner that could raster scan the focal point of the optics through a specimen and (iii) a silicon optical bench that connects the electromechanical and optical systems. The scanner was required to fit within a 7mm 0 endoscope port and scan at 1kHz throughout a 100xl00xl00 IPn3 volume. The results of this thesis were used to engineer a scanner that was capable of 3.5kHz x 100Hz x 30Hz scanning throughout a 125 x 200 x 200 jtm3 volume. Preceding jtTMA technology could only scan over 12.5% of the required volume at 10% of the required frequency. This work forms a body of knowledge - design rules, principles and best practices - that may be used to realize similar benefits in other small-scale devices.by Shih-Chi Chen.Ph.D