Use of COTS functional analysis software as an IVHM design tool for detection and isolation of UAV fuel system faults

This paper presents a new approach to the development of health management solutions which can be applied to both new and legacy platforms during the conceptual design phase. The approach involves the qualitative functional modelling of a system in order to perform an Integrated Vehicle Health Management (IVHM) design – the placement of sensors and the diagnostic rules to be used in interrogating their output. The qualitative functional analysis was chosen as a route for early assessment of failures in complex systems. Functional models of system components are required for capturing the available system knowledge used during various stages of system and IVHM design. MADe™ (Maintenance Aware Design environment), a COTS software tool developed by PHM Technology, was used for the health management design. A model has been built incorporating the failure diagrams of five failure modes for five different components of a UAV fuel system. Thus an inherent health management solution for the system and the optimised sensor set solution have been defined. The automatically generated sensor set solution also contains a diagnostic rule set, which was validated on the fuel rig for different operation modes taking into account the predicted fault detection/isolation and ambiguity group coefficients. It was concluded that when using functional modelling, the IVHM design and the actual system design cannot be done in isolation. The functional approach requires permanent input from the system designer and reliability engineers in order to construct a functional model that will qualitatively represent the real system. In other words, the physical insight should not be isolated from the failure phenomena and the diagnostic analysis tools should be able to adequately capture the experience bases. This approach has been verified on a laboratory bench top test rig which can simulate a range of possible fuel system faults. The rig is fully instrumented in order to allow benchmarking of various sensing solution for fault detection/isolation that were identified using functional analysis

Non-destructive testing of rock bolt fastening as an element of monitoring the state of mine workings

Purpose. To substantiate the informative parameter, to develop the method and equipment for non-destructive testing (NDT) of rock bolt fastening, as an element of geomechanical monitoring of the mine workings state. Methods. Analytical and bench experimental testing of shock-wave processes in the “rock bolt – bonding layer – rock massif” system. Findings. It has been established, that the non-destructive shock-wave method is the most satisfying for monitoring the geomechanical state of the “rock bolt – bonding layer – rock massif” system. This method is based on the registration and analysis of rock bolt oscillations, caused by non-normalized hit to the rock bolt end. It has been confirmed, that the most informative parameter is the relaxation time, that is the time over which the amplitude of oscillations decreases by “e” times. It has been shown, that clamping of the resin-grouted rock bolt in massif and its tensioning affects the relaxation time of damped oscillations. Furthermore, the relaxation time is inversely proportional to the degree of the rock bolt clamping, and is linked linearly with an increase in the rock bolt tensioning. The spectral composition of wedge shaped rock bolts self-oscillations, which are caused by impact excitation, depends both on the nature of clamping and on the rock bolt length, and makes it possible to identify the rock bolts by their length. Originality. The existence of a special type of damped longitudinal oscillations of the rock bolt in viscoelastic medium of the bonding layer has been established. The relaxation time of the specified type of oscillations was chosen as an informative parameter. An analytical link has been established between the informative parameter of shock-wave method of monitoring and the main indicators of rock bolt fastening quality: the degree of adhesion with massif and tension value. Practical implications. The method has been improved and equipment has been developed for non-destructive testing of rock bolt fastening, which makes it possible to control in-situ the rock bolt fastening quality, including the geomechanical state monitoring of mine workings.Мета. Обґрунтування інформативного параметра, розробка способу та апаратури неруйнівного контролю анкерного кріплення як елементів геомеханічного моніторингу стану гірничих виробок. Методика. Аналітичні та стендові експериментальні дослідження ударно-хвильових процесів в системі “анкер – закріплюючий шар – масив гірських порід”, апробація розробки в умовах шахт і підземних об’єктів цивільного та промислового призначення. Результати. Встановлено, що вимогам оперативності контролю з можливістю моніторингу геомеханічного стану системи “анкер – закріплюючий шар – масив” найбільш задовольняє ударно-хвильовий метод неруйнівного контролю, що реалізується шляхом нанесення ненормованого удару в торець анкера з реєстрацією та аналізом його коливань, при цьому найбільш інформативним та таким, що задовольняє ергономіці контролю, є параметр – час релаксації, за який амплітуда коливань зменшується в “е” разів. Показано, що ступінь защемлення сталеполімерного анкера в масиві та його натяг однозначно впливають на час релаксації затухаючого коливального процесу в системі “анкер – закріплюючий шар – масив”, при цьому зв’язок параметра з защемленням описується обернено пропорційною, а зв’язок з натягом анкера – лінійною залежністю. При ударному збудженні спектральний склад власних коливань клиновидних анкерів залежить як від характеру защемлення, так і від довжини анкера, що дозволяє при контролі виробок ідентифікувати анкери за їх довжиною. Наукова новизна. Встановлено існування особливого виду затухаючих поздовжніх коливань анкера в пружно-в’язкому середовищі закріплюючого шару. Як інформативний параметр вибрано час релаксації вказаного виду коливань, що в ергономічному діапазоні практично не залежить від сили збуджуючого удару. Встановлено аналітичний зв’язок між інформативним параметром ударно-хвильового методу контролю системи “анкер – закріплюючий шар – масив” і основними показниками якості металополімерного анкерного кріплення гірничих виробок: ступенем зчеплення з масивом та величиною натягу. Практична значимість. Вдосконалено метод і розроблено апаратуру неруйнівного контролю анкерного кріплення, які дозволяють оперативно у режимі моніторингу оцінювати якість закріплення анкера в масиві та його навантаження в умовах гірничих виробок діючого виробництва, зокрема, і у режимі системного геомеханічного моніторингу стану підземних виробок.Цель. Обоснование информативного параметра, разработка способа и аппаратуры неразрушающего контроля анкерного крепления как элементов геомеханического мониторинга состояния горных выработок. Методика. Аналитические и стендовые экспериментальные исследования ударно-волновых процессов в системе “анкер – закрепляющий слой – массив горных пород”, апробация разработки в условиях шахт и подземных объектов гражданского и промышленного назначения. Результаты. Установлено, что требованиям оперативности контроля с возможностью мониторинга геомеханического состояния системы “анкер – закрепляющий слой – массив” наиболее удовлетворяет ударно-волновой метод неразрушающего контроля, который реализуется путем нанесения ненормированного удара в торец анкера с регистрацией и анализом его колебаний, при этом наиболее информативным и таким, что удовлетворяет эргономике контроля, является параметр – время релаксации, за которое амплитуда колебаний уменьшается в “е” раз. Показано, что степень защемления сталеполимерного анкера в массиве и его натяжение однозначно влияют на время релаксации затухающего колебательного процесса в системе “анкер – закрепляющий слой – массив”, при этом связь параметра с защемлением описывается обратно пропорциональной, а связь с натяжением анкера – линейной зависимостью. При ударном возбуждении спектральный состав собственных колебаний клиновидных анкеров зависит как от характера защемление, так и от длины анкера, позволяет при контроле выработок идентифицировать анкеры по их длине. Научная новизна. Установлено существование особого вида затухающих продольных колебаний анкера в упруго-вязкой среде закрепляющего слоя. В качестве информативного параметра выбрано время релаксации указанного вида колебаний, которое в эргономичном диапазоне практически не зависит от силы возбуждающего удара. Установлена аналитическая связь между информативным параметром ударно-волнового метода контроля системы “анкер – закрепляющий слой – массив” и основными показателями качества металлополимерного анкерного крепления горных выработок: степенью сцепления с массивом и величиной натяжения. Практическая значимость. Усовершенствован метод и разработана аппаратура неразрушающего контроля анкерного крепления, которые позволяют оперативно в режиме мониторинга оценивать качество закрепления анкера в массиве и его нагружение в условиях горных выработок действующего производства, в том числе и в режиме системного геомеханического мониторинга состояния подземных выработок.The work results are part of the “Theories and me-thods development for geotechnical systems state ma-nagement to ensure mines performance intensification” research under National Academy of Sciences of Ukraine funding program

Increasing the Capacity of Primary Care Through Enabling Technology.

Primary care is the foundation of effective and high-quality health care. The role of primary care clinicians has expanded to encompass coordination of care across multiple providers and management of more patients with complex conditions. Enabling technology has the potential to expand the capacity for primary care clinicians to provide integrated, accessible care that channels expertise to the patient and brings specialty consultations into the primary care clinic. Furthermore, technology offers opportunities to engage patients in advancing their health through improved communication and enhanced self-management of chronic conditions. This paper describes enabling technologies in four domains (the body, the home, the community, and the primary care clinic) that can support the critical role primary care clinicians play in the health care system. It also identifies challenges to incorporating these technologies into primary care clinics, care processes, and workflow

A Dose Relationship Between Brain Functional Connectivity and Cumulative Head Impact Exposure in Collegiate Water Polo Players.

A growing body of evidence suggests that chronic, sport-related head impact exposure can impair brain functional integration and brain structure and function. Evidence of a robust inverse relationship between the frequency and magnitude of repeated head impacts and disturbed brain network function is needed to strengthen an argument for causality. In pursuing such a relationship, we used cap-worn inertial sensors to measure the frequency and magnitude of head impacts sustained by eighteen intercollegiate water polo athletes monitored over a single season of play. Participants were evaluated before and after the season using computerized cognitive tests of inhibitory control and resting electroencephalography. Greater head impact exposure was associated with increased phase synchrony [r (16) > 0.626, p < 0.03 corrected], global efficiency [r (16) > 0.601, p < 0.04 corrected], and mean clustering coefficient [r (16) > 0.625, p < 0.03 corrected] in the functional networks formed by slow-wave (delta, theta) oscillations. Head impact exposure was not associated with changes in performance on the inhibitory control tasks. However, those with the greatest impact exposure showed an association between changes in resting-state connectivity and a dissociation between performance on the tasks after the season [r (16) = 0.481, p = 0.043] that could also be attributed to increased slow-wave synchrony [F (4, 135) = 113.546, p < 0.001]. Collectively, our results suggest that athletes sustaining the greatest head impact exposure exhibited changes in whole-brain functional connectivity that were associated with altered information processing and inhibitory control

Intra-session and inter-day reliability of the Myon 320 electromyography system during sub-maximal contractions

Electromyography systems are widely used within the field of scientific and clinical practices. The reliability of these systems are paramount when conducting research. The reliability of Myon 320 Surface Electromyography System is yet to be determined. This study aims to determine the intra-session and inter-day reliability of the Myon 320 Surface Electromyography System. Muscle activity from fifteen participants was measured at the anterior deltoid muscle during a bilateral front raise exercise, the vastus lateralis muscle during a squat exercise and the extensor carpi radialis brevis (ECRB) muscle during an isometric handgrip task. Intra-session and inter-day reliability was calculated by intraclass correlation coefficient, standard error of measurement and coefficient of variation (CV). The normalized root mean squared (RMS) surface electromyographic signals produced good intra-session and inter-day testing intraclass correlation coefficient values (range: 0.63-0.97) together with low standard error of measurement (range: 1.49-2.32) and CV (range: 95% Confidence Interval = 0.36-12.71) measures for the dynamic-and-isometric contractions. The findings indicate that the Myon 320 Surface Electromyography System produces good to fair reliability when examining intra-session and inter-day reliability. Findings of the study provide evidence of the reliability of electromyography between trials which is essential during clinical testing.</p

A novel cooperative opportunistic routing scheme for underwater sensor networks

Increasing attention has recently been devoted to underwater sensor networks (UWSNs) because of their capabilities in the ocean monitoring and resource discovery. UWSNs are faced with different challenges, the most notable of which is perhaps how to efficiently deliver packets taking into account all of the constraints of the available acoustic communication channel. The opportunistic routing provides a reliable solution with the aid of intermediate nodes’ collaboration to relay a packet toward the destination. In this paper, we propose a new routing protocol, called opportunistic void avoidance routing (OVAR), to address the void problem and also the energy-reliability trade-off in the forwarding set selection. OVAR takes advantage of distributed beaconing, constructs the adjacency graph at each hop and selects a forwarding set that holds the best trade-off between reliability and energy efficiency. The unique features of OVAR in selecting the candidate nodes in the vicinity of each other leads to the resolution of the hidden node problem. OVAR is also able to select the forwarding set in any direction from the sender, which increases its flexibility to bypass any kind of void area with the minimum deviation from the optimal path. The results of our extensive simulation study show that OVAR outperforms other protocols in terms of the packet delivery ratio, energy consumption, end-to-end delay, hop count and traversed distance

Experimental study of visual corona under aeronautic pressure conditions using low-cost imaging sensors

Visual corona tests have been broadly applied for identifying the critical corona points of diverse high-voltage devices, although other approaches based on partial discharge or radio interference voltage measurements are also widely applied to detect corona activity. Nevertheless, these two techniques must be applied in screened laboratories, which are scarce and expensive, require sophisticated instrumentation, and typically do not allow location of the discharge points. This paper describes the detection of the visual corona and location of the critical corona points of a sphere-plane gap configurations under different pressure conditions ranging from 100 to 20 kPa, covering the pressures typically found in aeronautic environments. The corona detection is made with a low-cost CMOS imaging sensor from both the visible and ultraviolet (UV) spectrum, which allows detection of the discharge points and their locations, thus significantly reducing the complexity and costs of the instrumentation required while preserving the sensitivity and accuracy of the measurements. The approach proposed in this paper can be applied in aerospace applications to prevent the arc tracking phenomenon, which can lead to catastrophic consequences since there is not a clear protection solution, due to the low levels of leakage current involved in the pre-arc phenomenon.Peer ReviewedPostprint (published version

Predicting topology propagation messages in mobile ad hoc networks: The value of history

This research was funded by the Spanish Government under contracts TIN2016-77836-C2-1-R,TIN2016-77836-C2-2-R, and DPI2016-77415-R, and by the Generalitat de Catalunya as Consolidated ResearchGroups 2017-SGR-688 and 2017-SGR-990.The mobile ad hoc communication in highly dynamic scenarios, like urban evacuations or search-and-rescue processes, plays a key role in coordinating the activities performed by the participants. Particularly, counting on message routing enhances the communication capability among these actors. Given the high dynamism of these networks and their low bandwidth, having mechanisms to predict the network topology offers several potential advantages; e.g., to reduce the number of topology propagation messages delivered through the network, the consumption of resources in the nodes and the amount of redundant retransmissions. Most strategies reported in the literature to perform these predictions are limited to support high mobility, consume a large amount of resources or require training. In order to contribute towards addressing that challenge, this paper presents a history-based predictor (HBP), which is a prediction strategy based on the assumption that some topological changes in these networks have happened before in the past, therefore, the predictor can take advantage of these patterns following a simple and low-cost approach. The article extends a previous proposal of the authors and evaluates its impact in highly mobile scenarios through the implementation of a real predictor for the optimized link state routing (OLSR) protocol. The use of this predictor, named OLSR-HBP, shows a reduction of 40–55% of topology propagation messages compared to the regular OLSR protocol. Moreover, the use of this predictor has a low cost in terms of CPU and memory consumption, and it can also be used with other routing protocols.Peer ReviewedPostprint (published version

Challenges in quantifying changes in the global water cycle

Human influences have likely already impacted the large-scale water cycle but natural variability and observational uncertainty are substantial. It is essential to maintain and improve observational capabilities to better characterize changes. Understanding observed changes to the global water cycle is key to predicting future climate changes and their impacts. While many datasets document crucial variables such as precipitation, ocean salinity, runoff, and humidity, most are uncertain for determining long-term changes. In situ networks provide long time-series over land but are sparse in many regions, particularly the tropics. Satellite and reanalysis datasets provide global coverage, but their long-term stability is lacking. However, comparisons of changes among related variables can give insights into the robustness of observed changes. For example, ocean salinity, interpreted with an understanding of ocean processes, can help cross-validate precipitation. Observational evidence for human influences on the water cycle is emerging, but uncertainties resulting from internal variability and observational errors are too large to determine whether the observed and simulated changes are consistent. Improvements to the in situ and satellite observing networks that monitor the changing water cycle are required, yet continued data coverage is threatened by funding reductions. Uncertainty both in the role of anthropogenic aerosols, and due to large climate variability presently limits confidence in attribution of observed changes