167 research outputs found
Radio Frequency Based Programmable Logic Controller Anomaly Detection
The research goal involved developing improved methods for securing Programmable Logic Controller (PLC) devices against unauthorized entry and mitigating the risk of Supervisory Control and Data Acquisition (SCADA) attack by detecting malicious software and/or trojan hardware. A Correlation Based Anomaly Detection (CBAD) process was developed to enable 1) software anomaly detection discriminating between various operating conditions to detect malfunctioning or malicious software, firmware, etc., and 2) hardware component discrimination discriminating between various hardware components to detect malfunctioning or counterfeit, trojan, etc., components
Recommended from our members
Compressive Sampling and Feature Ranking Framework for Bearing Fault Classification with Vibration Signals
Failures of rolling element bearings are amongst the main causes of machines breakdowns. To
prevent such breakdowns, bearing health monitoring is performed by collecting data from rotating machines,
extracting features from the collected data, and applying a classifier to classify faults. To avoid the burden of
much storage requirements and processing time of a tremendously large amount of vibration data, the present
paper proposes a combined Compressive Sampling (CS) based on Multiple Measurement Vector (MMV) and
Feature Ranking (FR) framework to learn optimally fewer features from a large amount of vibration data
from which bearing health conditions can be classified. The CS-based on MMV model is the first step in this
framework and provides compressively-sampled signals based on compressed sampling rates. In the second
step, the search for the most important features of these compressively-sampled signals is performed using
feature ranking and selection techniques. For that purpose, we have investigated the following: (1) two
compressible representations of vibration signals that can be used within CS framework, namely, Fast Fourier
Transform (FFT) based coefficients and thresholded Wavelet Transform (WT) based coefficients, and (2)
several feature ranking and selection techniques, namely, three similarity-based techniques, Fisher Score
(FS), Laplacian Score (LS), Relief-F; one correlation-based technique, Pearson Correlation Coefficients
(PCC); and one independence test technique, Chi-Square (Chi-2) to select fewer features that can sufficiently
represent the original vibration signals. These selected features, in combination with three of the popular
classifiers - multinomial Logistic Regression classifier (LRC), Artificial Neural Networks (ANNs), and
Support Vector Machines (SVMs), have been evaluated for the classification of bearing faults. Results show
that the proposed framework achieves high classification accuracies with a limited amount of data using
various combinations of methods, which outperform recently published results
Frugal innovation for healthcare: strategies and tools for the identification and evaluation of frugal and reverse innovations in healthcare
Global healthcare systems are united by their desire to widen patient access to safe and effective clinical services in the face of increasing demand and financial
constraints. In low- and middle-income countries (LMICs), a variety of ingenious product and process solutions, termed frugal innovations, have been able to deliver services at a fraction of the cost. It is the broad proposition of this work that such ideas could be applicable to high-income countries (HICs), a concept labeled reverse innovation. Using a conceptual model of innovation scouting derived from the causal mechanism of critical realism, this work examined the development and testing of a tool to deductively identify frugal innovations in healthcare (FIH-ID tool) and then evaluated methodology to assess the reversibility of potential of frugal innovations.
The FIH-ID tool demonstrated consistently acceptable inter-rater reliability scores using different methods of application and different raters, moreover, construct validity was shown by its ability to identify well-known frugal innovations. With respect to the assessment of the reversibility potential, the results of the present study highlighted the challenges of undertaking such a complex evaluation process using a simple scoring system. Raters achieved poor levels of inter-rater reliability and only 2 innovations were thought likely to reverse to a HIC.
This study presents the first application of a critical realist approach to innovation scouting. It has identified a cohort of 76 potential frugal innovations in healthcare suggesting that the FIH-ID tool is likely to be a valuable asset for similar studies in the future. It has highlighted the challenges of assessing the reversibility potential of innovations from LMICs. It has documented the emergence of the global innovation curator, entities that seek to identify, curate and promote innovations from LMICs, and it proposes a conceptual model for the role of global innovation curators in the diffusion of innovation.Open Acces
Numeričko modeliranje kemijske kinetike samozapaljenja u računalnoj dinamici fluida
Glavna namjera istraživanja ovog rada je izvesti numerički učinkovite algoritme za modeliranje zapaljenja goriva s posebnim fokusom na fenomen niskotemperaturnog zapaljenja. \Numerička simulacija niskotemperaturnog zapaljenja dosad se uglavnom postizala računalno zahtjevnim izračunima složene kemijske kinetike, dok će ovaj rad pokušati razviti nove postupke učinkovite izrade baza podataka koje sadrže informacije o efektima složene kemijske kinetike potrebne za simulaciju zapaljenja goriva. Istraživanje je jasno podijeljeno u nekoliko faza: pred-procesiranje, tabelacija s post-procesiranjem podataka, te na kraju implementacija u CFD aplikaciju. U prvoj fazi, pred-procesiranju, detaljno su predstavljeni dostupni reakcijski mehanizmi za popularna goriva, te su isti međusobno uspoređeni prema njihovoj točnosti i kompleksnosti. Zatim je prikazan način modeliranja nuladimenzijskog proračuna s kriterijima određivanja nisko- i visokotemperaturnog zapaljenja. U sljedećoj fazi, post-procesiranju, predloženi su alati za manipulaciju izračunatim podacima, s posebnim fokusom na popunjavanje krnjih baza podataka korelacijskim funkcijama i matematičkim algoritmima. Dodatno, predložen je i način korištenja postojećih podataka za pojedina goriva pri izračunavanju karakterističnih veličina za njihovu smjesu. U tom se slučaju koriste samo vrijednosti za izgaranje svako goriva (čistog) i faktor miješanja. Princip je provjeren na gorivu varijacijom istraživačkog oktanskog broja. \Na kraju, prikazana je implementacija u CFD aplikaciju te je ista i validirana u dvije faze. Prvo je napravljena usporedba s proračunom homogenog kemijskog reaktora s kompleksnim reakcijskim mehanizmom a na samom kraju i primjer stvarne komore izgaranja što je pokazalo valjanost modela i cijele procedure
Recommended from our members
Defense Technical Information Center thesaurus
This DTIC Thesaurus provides a basic multidisciplinary subject term vocabulary used by DTIC to index and retrieve scientific and technical information from its various data bases and to aid DTIC`s users in their information storage and retrieval operations. It includes an alphabetical posting term display, a hierarchy display, and a Keywork Out of Context (KWOC) display
Ahlfors circle maps and total reality: from Riemann to Rohlin
This is a prejudiced survey on the Ahlfors (extremal) function and the weaker
{\it circle maps} (Garabedian-Schiffer's translation of "Kreisabbildung"), i.e.
those (branched) maps effecting the conformal representation upon the disc of a
{\it compact bordered Riemann surface}. The theory in question has some
well-known intersection with real algebraic geometry, especially Klein's
ortho-symmetric curves via the paradigm of {\it total reality}. This leads to a
gallery of pictures quite pleasant to visit of which we have attempted to trace
the simplest representatives. This drifted us toward some electrodynamic
motions along real circuits of dividing curves perhaps reminiscent of Kepler's
planetary motions along ellipses. The ultimate origin of circle maps is of
course to be traced back to Riemann's Thesis 1851 as well as his 1857 Nachlass.
Apart from an abrupt claim by Teichm\"uller 1941 that everything is to be found
in Klein (what we failed to assess on printed evidence), the pivotal
contribution belongs to Ahlfors 1950 supplying an existence-proof of circle
maps, as well as an analysis of an allied function-theoretic extremal problem.
Works by Yamada 1978--2001, Gouma 1998 and Coppens 2011 suggest sharper degree
controls than available in Ahlfors' era. Accordingly, our partisan belief is
that much remains to be clarified regarding the foundation and optimal control
of Ahlfors circle maps. The game of sharp estimation may look narrow-minded
"Absch\"atzungsmathematik" alike, yet the philosophical outcome is as usual to
contemplate how conformal and algebraic geometry are fighting together for the
soul of Riemann surfaces. A second part explores the connection with Hilbert's
16th as envisioned by Rohlin 1978.Comment: 675 pages, 199 figures; extended version of the former text (v.1) by
including now Rohlin's theory (v.2
Quantum systems engineering
With the aim of defining a Quantum Systems Engineering paradigm, we show that the systems engineering of quantum technologies is materially different from systems engineering in general. The thesis is based upon a two pronged mixed-methods research approach considering: (a) a comprehensive theoretical analysis of the difficulties in deriving systems engineering modelling tools; (b) identifying systems engineering challenges in practical quantum technology development through direct observation and case-study methods. We show a modified systems approach should benefit early stage quantum technologies design and development, a stage characterised by a low Technology Readiness Level (TRL), with the aim of accelerating capitalisation. The research showed that systems engineering applied to quantum technologies will require processes that are both more complex, and different from, those used for conventional systems technology development. This is fundamentally caused by the quantum properties of the system. Furthermore, the research evidenced that applying systems methods, tools, and approaches to low Technology Readiness Level development, both quantum and classical, is very likely to accelerate development, increase the quality of deliverables, and improve the alignment of early research to end-user needs and natural technology pull. Based on these results we have developed a series of recommendations, and a selection of systems tools, which together constitute a light-weight systems approach for low Technology Readiness Level development (some of which also apply to non-quantum domains). These are contained within the concluding chapter of the report. Findings are presented both as a verbal narrative and with full mathematical derivations
Annual Report of the University, 1968-1969, Volumes 1 & 2
At least once every ten years the University of New Mexico has a chance to see itself as others sec it. The opportunity is provided by its accrediting agency. Routinely every decade, the North Central Association of Colleges and Secondary Schools sends a team of scholars and administrators to campus to determine whether the University is maintaining the prerequisites to continuing accreditation as a doctoral degree granting institution. While the examination is scheduled routinely, it is by no means a routine visit. The visitation team probes such areas as curricula, library, finances, administration, day-to-day operations, and long-range plans. Its report, much like that of an auditor, helps provide operational guidelines for succeeding years. The University of New Mexico in 1969 underwent its decennial examination by the North Central Association. The team of visitors prepared a comprehensive report touching on many areas vital to the University\u27s future. Findings of the committee and the University\u27s responses to them serve as the basis for this annual report of the President
- …