Academic literature on the topic 'Multi-anchor configuration'

Multi-scale object detection within Synthetic Aperture Radar (SAR) images has become a research hotspot in SAR image interpretation. Over the past few years, CNN-based detectors have advanced sharply in SAR object detection. However, the state-of-the-art detection methods are continuously limited in Feature Pyramid Network (FPN) designing and detection anchor setting aspects due to feature misalignment and targets’ appearance variation (i.e., scale change, aspect ratio change). To address the mentioned limitations, a scale-aware feature pyramid network (SARFNet) is proposed in this study, which comprises a scale-adaptive feature extraction module and a learnable anchor assignment strategy. To be specific, an enhanced feature pyramid sub-network is developed by introducing a feature alignment module to estimate the pixel offset and contextually align the high-level features. Moreover, a scale-equalizing pyramid convolution is built through 3-D convolution within the feature pyramid to improve inter-scale correlation at different feature levels. Furthermore, a self-learning anchor assignment is set to update hand-crafted anchor assignments to learnable anchor/feature configuration. By using the dynamic anchors, the detector of this study is capable of flexibly matching the target with different appearance changes. According to extensive experiments on public SAR image data sets (SSDD and HRSID), our algorithm is demonstrated to outperform existing boat detectors.

An anchoring system for an offshore structure must meet certain prescribed requirements controlled by factors such as the site environment, operational constraints and the vessel employed. Its adequacy, survival and ability to stay on site must, therefore, be checked out with proper methods of analysis. The inclusion of cable dynamics is an important consideration in the dynamic analysis of a moored vessel. In this paper, mooring line equations of motion are derived for a multi-component, n-segment model using Lagrange’s modified equation, permitting anchor motion, and then numerically solved to yield time histories of cable displacements and cable tensions for the various cable configurations that can occur. Initial conditions can be provided through the mooring line static catenary equations. The nonlinear restoring force terms in the vessel equations of motion are generated through the dynamic tension- displacement characteristics of individual lines. The equations of motion of the moored vessel subjected to an open ocean environment are then numerically solved to yield time histories of vessel motions and cable tensions. An example involving a moored production barge is examined and results are compared with those of previous work in which a quasi-static cable configuration is employed.

The use of tethered Unmanned Aircraft Systems (UAS) in aerial robotic applications is a relatively unexplored research field. This work addresses the attitude and position estimation of a small-size unmanned helicopter tethered to a moving platform using a multi-sensor data fusion algorithm based on a numerically efficient sigma-point Kalman filter implementation. For that purpose, the state prediction is performed using a kinematic process model driven by measurements of the inertial sensors (accelerometer and gyroscope) onboard the helicopter and the subsequent correction is done using information from additional sensors like magnetometer, barometric altimeter, LIDAR altimeter and magnetic encoders measuring the tether orientation relative to the helicopter. Assuming the tether is kept taut by an actuated device on the platform during the system operation, the helicopter position is estimated relative to the anchor point. Although this configuration avoids the need of a GPS, a standard operation mode for estimation of the absolute position (the position relative to the inertial reference frame) incorporating corrections with the GPS position and velocity measurements, is also implemented in order to highlight the benefits of the proposed tethered setup. The filter performance is evaluated in simulations.

In this paper, we present a novel Deep Neural Network-based indoor localization method that estimates the position of a Bluetooth Low Energy (BLE) transmitter (tag) by using the received signals’ characteristics at multiple Anchor Points (APs). We use the received signal strength indicator (RSSI) value and the in-phase and quadrature-phase (IQ) components of the received BLE signals at a single time instance to simultaneously estimate the angle of arrival (AoA) at all APs. Through supervised learning on simulated data, various machine learning (ML) architectures are trained to perform AoA estimation using varying subsets of anchor points. In the final stage of the system, the estimated AoA values are fed to a positioning engine which uses the least squares (LS) algorithm to estimate the position of the tag. The proposed architectures are trained and rigorously tested on several simulated room scenarios and are shown to achieve a localization accuracy of 70 cm. Moreover, the proposed systems possess generalization capabilities by being robust to modifications in the room’s content or anchors’ configuration. Additionally, some of the proposed architectures have the ability to distribute the computational load over the APs.

Cable-based technologies are the backbone for logistics of timber or construction material on impassable terrain. In Central Europe, the use of standing skylines with pre-stressed, both-sided fixed-anchor cables and multi-span configurations with internal intermediate supports is common. To ensure a safe and cost-effective set-up for cable road operations, it is essential to identify and compute the properties of the skyline (e.g. load path, tensile forces). This task is challenging because it requires dealing with the non‐linear behaviour of the cable structure under the load and has to include all significant physical effects. Several approaches have previously been proposed as practical solutions, however not all physical effects were covered by those approaches, such as the inclination-dependent elastic prolongation of the cable or the longitudinal deflection of the sagging carriage. With our new proposed approach, we aim to close this gap of knowledge, and consider all relevant physical effects. We present a non-linear approach that is able to compute the properties of a wide range of standing skyline configurations, including those with additional cables. This approach offers an extensive solution and a flexible framework for considering individual configurations or particularities by adding equations to the equation system.

Changes to building codes that enable use of materials such as cross-laminated timber (CLT) in mid- and high-rise construction are facilitating sustainable urban development in various parts of the world. Keys to this are the transition to multi-performance-based design approaches along with fewer limitations on heights or the number of storeys in superstructures constructed from combustible materials. Architects and engineers have increased freedom to apply new design and construction concepts and methods, as well as to combine timber with other structural materials. They also have started to develop wall arrangements that optimise interior space layouts and take advantage of the unique characteristics of CLT. This paper discusses the seismic response of multi-story buildings braced with a CLT core and perimeter shear walls anchored to foundations and floor platforms using modern high-capacity angle brackets and hold-downs, or X-Rad connectors. Linear dynamic finite element (FE) models of seismic responses of superstructures of various heights are presented, based on experimentally determined characteristics of wall anchor connections. Particular attention is given to fundamental vibration periods, base shear and uplift forces on walls, as well as inter-story drift. Discussion of FE model results focuses on structural engineering implications and advantages of using CLT to create shear walls, with emphasis on how choice of wall anchoring connections impacts the possible number of storeys and configurations of superstructures. Employing CLT shear walls with X-Rad or other types of high capacity anchoring connections makes possible the creation of building superstructures having eight and potentially more storeys even in high seismicity regions. However, it is important to emphasise that proper selection of suitable arrangements of shear walls for CLT buildings depends on accurate representation of the semi-rigid behaviors of anchoring connections. The linear dynamic analyses presented here demonstrates the need during engineering seismic design practices to avoid use of FE or other design models which do not explicitly incorporate connection flexibilities while estimating parameters like fundamental periods, base shear and uplift forces, as well as inter-story drift.

Nearly 50 years on from Alvin Toffler’s Future Shock (1971), contemporary society finds itself navigating the Fourth Industrial Revolution. This era has been described as the convergence of digitisation, robotics, artificial intelligence, globalisation—and speed (Johannessen). As such, temporality is taking on a turbulent and elusive edge. In the previous century, Toffler highlighted that technological change accelerated perceptions of time, and he predicted that by the 21st century, people would find it “increasingly painful to keep up with the incessant demand for change that characterises our time”, where change would come about “with waves of ever accelerating speed and unprecedented impact” (18). While Toffler could not have predicted the exact nature and detail of the specificities of day-to-day life in 2019, we suggest Toffler’s characterisation marks an insightful ‘jumping off’ point for further introspection. With Toffler’s concerns in mind, this issue of M/C Journal is interested in multiple ways that digital media influences and expresses conceptions of temporality in this historical period, the final weeks of 2019. On the basis of the pieces that comprise this issue, we take this concern further to politicise the temporal figurations of media, which we propose permeate all aspects of contemporary experience. Theoretically, this position pays homage to the work performed by Jay Bolter and Richard Grusin more than two decades ago. In 1996, Bolter and Grusin ruminated on the “the wire”, a fictional device that was the central focus of the film Strange Days (1995), a media gadget that could mediate experience from one subject to another, “pure and uncut, straight from the cerebral cortex” (311). For Bolter and Grusin, ‘the wire’ epitomised contemporary culture’s movement toward virtual reality, “with its goal of unmediated visual and aural experience” and they suggested that the film provided a critique of the historical mode “in which digital technologies are proliferating faster than our cultural, legal, or educational institutions can keep up with them” (313). For us, perhaps even more urgently, the wire epitomises the colonisation, infiltration and permeation of the production of temporal layers through media systems and devices into the subject’s direct experience. The wire symbolises, among many things, a simulation of the terrain of time according to the Jorge Luis Borges fable, that is, one-for-one.Contingent upon new shifts, and the academic literature which has sought to critique them thus far, in this editorial, we raise the contention that the technologies and operations of power brought about through the Fourth Industrial Revolution, and its media apparatus, have exposed the subject to a multiplicity of timescapes. In doing so, these configurations have finally colonised subjective experience of time and temporality.Consequently, we have specifically featured a broad selection of articles that explore and discuss the presence of online, mobile, or streamed media as the primary means through which culture understands, expresses, and communicates the world, and ideas around temporality. The articles featured herein explore the ways in which constructs of time organise (and are organised by) other constructs such as; neoliberalism (Bianchino), relaxation (Pont), clocks (Cambpell), surveillance, biopower, narrative (Glitsos), monetisation (Grandinetti), memorialising (Wishart), time travel (Michael), utopias and dystopias (Herb). Through the spectrum of topics, we hope to elucidate to the reader the ways in which digital culture performs and generates ontological shifts that rewrite the relationship between media, time, and experience.ContemporaneityA key concern for us in this issue is the idea of ‘contemporaneity,’ which has been discussed more recently in art theory and criticism by Terry Smith, and Peter Osborne, amongst others. Both Smith and Osborne use the term to articulate the effects of contemporary globalisation, transnationalism, and post-conceptual art. Smith reminds us that in contemporary society there isthe insistent presentness of multiple, often incompatible temporalities accompanied by the failure of all candidates that seek to provide the overriding temporal framework – be it modern, historical, spiritual, evolutionary, geological, scientific, globalizing, planetary. (196)As a result, artists are negotiating and critiquing multiple intersecting and contradictory time codes that pervade contemporary society in order to grapple with contemporaneity today. Yet, concerns with overlayed temporalities enter our everyday more and more, as explored through Justin Grandinetti’s piece, “A Question of Time: HQ Trivia and Mobile Streaming Temporality”, in which he interrogates mobile streaming practices and the ways in which new devices seek out every possible moment that might be monetised and ‘made productive.’Grandinetti’s concern, like the others featured in this issue, attends to the notion of time as evasive, contradictory and antonymous while forming a sense of urgency around the changing present, and also reconciling a multiplicity of time codes at play through technology today. The present is immediately written and archived through news media live feeds, GPS tracking and bio data in apps used for fitness and entertainment amongst others, while the pace of national television, print media, and local radio is folded through our daily experiences. Consequently, we’re interested in the multiple, and sometimes incompatible temporalities that emerge through the varied ways in which digital media is used to express, explore, and communicate in the world today beyond the arenas of contemporary art and art history that Smith and Osborne are primarily concerned with. ExperienceExperience is key. Experience may in fact be the key that unlocks these following conversations about time and the subject, after all, time is nothing if not experiential. Empirically, we might claim that, time is “conceived as the intervals during which events occur” (Toffler 21). However, of course one can only be if one is being in time. Through Bergson we might say that the individual’s perception of time manifests “rightly or wrongly, to be inside and outside us at one and the same time … . To each moment of our inner life there thus corresponds a moment of our body and of all environing matter that is ‘simultaneous’ with it” (205). Time is the platform through which experience of consciousness is mediated, thus the varying manipulations of time through media apparatuses are therefore inextricable with our lived ‘everyday’.E.P. Thompson might call this our “time-sense”, a kind of “inward notation of time” (58), however this rationalisation of time is amplified and complicated by digital media, as warned by Campbell in this issue. Campbell explores the performativity of publicly writing the self on social media that commodifies experience. An inward notion of time therefore becomes inverted and publicly performed through digital media, which is a key source of anxiety and control for individuals. In Toffler’s estimation, even by as early as the 1970s the technoscience of Western culture had “released a totally new social force” and he contends that this had reshaped the collective psyche witha stream of change so accelerated that it influences our sense of time, revolutionizes the tempo of daily life, and affects the very way we “feel” the world around us. We no longer “feel” life as men [sic] did in the past. And this is the ultimate difference, the distinction that separates the truly contemporary man [sic] from all others. (17)While Toffler was referring to a different technological context, he serves as a reminder that digital media amplifies pre-existing effects of technology. Therefore, while autofiction and the public writing of the self is not necessarily new, it is nevertheless key to contemporary feelings of acceleration and the temporal vernacular of contemporaneity – one that exacerbates the experiences of acceleration, inertia, and how we ‘feel’ the present and our presence in the world.In this issue we also wish to note the ways in which digital culture, and perhaps in particular new media platforms and narratives that permeate our homes, appear to be directing the Western “time-sense” (Thompson 80) away from metaphors constructed through the linear trope of ‘rivers’ or ‘streams’ and toward the more complex arrangements that we suggest are more suited to metaphors of ‘confetti’ or ‘snow’, as Laura Glitsos elucidates in her piece “From Rivers to Confetti: Reconfigurations of Time through New Media Landscapes”.As just one example, we might think of the multiplicity of ‘peculiar times’ built upon each other in the production, distribution, consumption and convergence of so many levels of digital media. In one sense, we might approach ‘peculiar times’ as the peculiarity of temporality in any given context. However, in another sense, we might also recognise the layering of standardisation which is then peculiar to each of the modes of production, consumption, and distribution (as laid out by Althusser and Balibar). As just one example, in the context of streaming services, we find the “flattening of historical frames” (Kaplan 144) in the scrolling back and forward on social media timelines (Powell 2). So perhaps our peculiar time speaks of the collapsing between ontological boundaries of past, present, and future—a kind of contemporaneity that splits between the peculiarities of production and consumption of digital media.StandardisationHistoriographies of time-sense in the Western tradition have been covered by thinkers as diverse as E.P. Thompson, Graeme Davidson, Bernard Stiegler, and Henri Lefebvre. While it is not our aim to repeat those narratives here, we concede some markers are crucial to note in order to set the context for our selected pieces. Beginning in the early- to mid- middle ages in Europe, up until the spread of clocks in the 14th century, time was largely related to processes, tasks or stages of light during the day, and time does still continues to exist in this way for some communities (Thompson 58). During this era, and of even back to the third century BCE, there were time-keeping technologies which could measure smaller increments of the day, such as the water-clock, the sun-dial, and the hour-glass, but everyday activities for the working people were largely regulated by natural or circadian rhythms (Thompson). It is perhaps these rhythms which served to shape the ‘inward notation of time’, in Thompson’s words, through the discourses of nature, that is through the language of streams and rivers—or ‘flows’.The 13th century saw the advent of mechanical time-keeping technology utilising what is called a “verge escapement mechanism”, that is, a “feedback regulator that controls the speed of a mechanical clock” (Headrick 42). About a century later, coupled with the emergence of puritanism, Thompson tells us that we start to see a shift in the construction of time which more and more depends on the synchronisation of labour (Thompson 70). Even so, working rhythms remain fairly irregular, still more suited to what Thompson describes as “a natural human rhythm” (71). This changes suddenly in the 19th century when, with the explosion of the Industrial Age, we witness the dominance of factory-time and, of course, the adoption and standardisation of railway-time across Britain, Europe, India and North America (Schivelbusch). The trend toward standardisation continues into the mid-20th century with what George Ritzer has famously called “McDonaldization” (2008). Thus, through the blanketing nature of 20th century “industrial capitalism” (Thompson 80), everyday experience became predicated on standardisation. Thompson tells us that these “changes in manufacturing technique … demand greater synchronization of labour and a greater exactitude in time-routines in society” (80). For Thompson, the “technological conditioning” of “time-sense” ushers in the model of “time-measurement as a means of labour exploitation” (80). This historical point is central to Giacomo Bianchino’s argument in “Afterwork and Overtime: The Social Reproduction of Human Capital”, in his discussion of the fundamental nature of capitalism in shaping time-sense. However, what we suggest is that this theme of ‘time-sense’ as shaped by the broader political economy of media is found within each of the pieces in the issue.A discussion of standardisation is problematic, however, in the wider conceptualisation of time as elusive, multi-dynamic and fractured. Surely, standardisation should at least come with the ability of certainty, in some respects. However, this is the paradox of the digital and new media age: That standardisation is both arbitrary and, in echo of Balibar and Althusser, ‘peculiar’ to an endless layering of separate time-streams. It is, perhaps, the jumping between them, which has become a necessary function of living in the digital age, that produces the sense of fracture, the loss of standard.This issue of M/C Journal explores the various ways in which the constellation of current media practices that are online, offline, embodied, and networked, collectively inform and express concepts of time. The feature article "With This Body, I Subtract Myself from Neoliberalised Time: Sub-Habituality & Relaxation after Deleuze", written by Antonia Pont, keenly asks how relaxation might be used to evade neoliberal machinations around organising time, efficiency, and productivity, all of which endanger a diversity of temporalities. While all media have their own unique limitations and affordances regarding influencing and expressing relationships to time, they are also impacted by current perceptions of uncertainty and neoliberal agendas that underlie the working relationships between people, the media that they engage in, and representations of the world.The feelings of inertia expressed by Toffler nearly 50 years ago has not only been accelerated through technological expansion, but by a layering of multiple time codes which reflect the wide range of media practices that permeate the contemporary vernacular. In 2019, concepts from the current post-Internet stage are beginning to emerge and we are finding that digital media fragments as much as it connects and unites. An ‘inward notion of time’ becomes brokered through automated processes, issues around surveillance, affect, standardisation, norms, nostalgia, and the minutiae of digital time.ReferencesAlthusser, Louis, and Etienne Balibar. Reading Capital. London: NBL, 1970.Ansell-Pearson, Keith, John Ó Maoilearca, and Melissa McMahon. Henri Bergson: Key Writings. New York: Continuum, 2002.Bolter, Jay, and Richard Grusin. “Remediation.” Configurations 4.3 (1996): 311-358.Davison, Graeme. The Unforgiving Minute: How Australia Learned to Tell the Time. Melbourne: Oxford UP, 1993.Headrick, M.V. “Origin and Evolution of the Anchor Clock Escapement.” IEEE Control Systems 22.2 (2002): 41-52.Johannessen, Jon-Arild. Automation, Innovation and Economic Crisis: Surviving the Fourth Industrial Revolution. Milton: Routledge, 2018.Kaplan, E. Ann. Rocking around the Clock: Music Television, Postmodernism, and Consumer Culture. New York: Methuen, 1987.Powell, Helen. Stop the Clocks! Time and Narrative in Cinema. London: I.B. Tauris, 2012.Ritzer, George. The McDonaldization of Society. Los Angeles: Pine Forge P, 2008.Schivelbusch, Wolfgang. The Railway Journey: The Industrialization of Time and Space in the Nineteenth Century. Oakland: U of California P, 2014.Smith, Terry. What Is Contemporary Art? Chicago: U of Chicago P, 2009.Thompson, E.P. “Time, Work-Discipline, and Industrial Capitalism.” Past and Present 38.1 (1967): 56-97.Toffler, Alvin. Future Shock. London: Bodley Head, 1970.

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.09.01 "Електричні машини й апарати" (14 – Електрична інженерія) – Національний технічний університет "Харківський політехнічний інститут", м. Харків, 2020 р. Дисертаційна робота присвячена удосконаленню лінійних імпульсних електромеханічних перетворювачів за рахунок мультиякірних конфігурацій. Для досягнення цієї мети були поставлені задачі: – провести аналіз конструкцій та сфер використання лінійних імпульсних електромеханічних перетворювачів індукційного, електродинамічного і електромагнітного типів в якості ударно-силових та прискорювальних пристроїв; – реалізувати в програмному середовищі COMSOL Multiphysics математичну модель лінійного імпульсного електромеханічного перетворювача мультиякірної конфігурації, яка враховує взаємопов’язані електричні, магнітні, механічні і теплові процеси та нелінійні магнітні і теплофізичні залежності; – провести аналіз електромеханічних характеристик лінійних імпульсних електромеханічних перетворювачів мультиякірних конфігурацій та за допомогою комплексного критерію оцінити їх ефективність; – встановити вплив форми струму збудження на ефективність лінійних імпульсних електромеханічних перетворювачів мультиякірних конфігурацій; – провести експериментальні дослідження лінійних імпульсних електромеханічних перетворювачів, запропонувати та випробувати моделі електромагнітної катапульти для безпілотного літального апарату, магнітно-імпульсного пресу для керамічних порошкових матеріалів, електромеханічного пристрою для скидання ожеледних та снігових відкладень з проводу лінії електропередачі та пристрою для знищення інформації на SSD накопичувачі. Об’єкт дослідження – електромеханічні процеси та показники лінійних імпульсних електромеханічних перетворювачів мультиякірних конфігурацій. Предмет дослідження – лінійні імпульсні електромеханічні перетворювачі мультиякірних конфігурацій силового та швидкісного призначення. Методи дослідження. При розв’язанні поставлених задач використовувалось математичне моделювання електромагнітних, механічних та теплофізичних процесів в лінійних імпульсних електромеханічних перетворювачах імпульсної дії для проведення аналізу електромеханічних характеристик та встановлення впливу форми струму збудження на ефективність перетворювачів. Експериментальні дослідження лінійних імпульсних електромеханічних перетворювачів мультиякірної конфігурації проводились на експериментальних стендах, що дозволило випробувати моделі пристроїв. В роботі отримані такі наукові результати: – отримала подальший розвиток класифікація лінійних імпульсних електромеханічних перетворювачів мультиякірних конфігурацій, які включають феромагнітний, котушковий та суцільний електропровідний якоря; – удосконалено математичну модель лінійного імпульсного електромеханічного перетворювача за рахунок включення феромагнітного, котушкового та суцільного електропровідного якорів, які взаємодіють з рухомим якорем. Математична модель, яка реалізована в програмному середовищі COMSOL Multiphysics, містить взаємопов’язані електричні, магнітні, механічні та теплові процеси і враховує магнітні та теплофізичні нелінійні залежності; – вперше встановлено особливості протікання електромагнітних процесів та визначено електричні, магнітні та силові показники лінійних імпульсних електромеханічних перетворювачів мультиякірних конфігурацій силового призначення. Показано що практично всі перетворювачі мультиякірних конфігурацій забезпечують збільшення амплітуди та величини імпульсу електродинамічних зусиль у порівнянні з перетворювачем, що має один суцільний електропровідний якір; – вперше встановлено вплив геометричних параметрів рухомого і нерухомого електропровідних якорів, які взаємодіють з рухомим індуктором, що дозволило підвищити швидкісні показники лінійного імпульсного електромеханічного перетворювача; – вперше встановлено, що при збуджені коливально-загасаючою, аперіодичною та аперіодичною з підживленням формами струму в перетворювачах мультиякірних конфігурацій величина імпульсу електродинамічних зусиль збільшується у порівнянні з перетворювачем, що має один суцільний електропровідний якір. Дисертаційна робота виконана в НТУ "ХПІ" і є частиною науково-дослідних робіт кафедри загальної електротехніки. Робота виконувалися за держбюджетними темами "Розробка засобів підвищення ефективності лінійних ударних електромеханічних прискорювачів та силових пристроїв" (ДР № 0115U000522) і "Удосконалення технічних систем та пристроїв за рахунок імпульсних електромеханічних перетворювачів та електрофізичних технологій" (ДР № 0117U004881), госпдоговірної теми № 15812 "Розробка та дослідження високошвидкісного електродинамічного приводу" і ініціативної теми "Сучасні проблеми та перспективи розвитку електротехнічних пристроїв та систем" (ДР № 0119U002551), де автор був співвиконавцем.
Dissertation for Candidate of Science Degree in Specialty 05.09.01 "Electrical Machines and Apparatuses" (14 – Electrical Engineering) – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2020. The dissertation work is devoted to the improvement of linear pulse electromechanical converters due to multi - core configurations. To achieve this goal, the following tasks were set: – to analyze the structures and areas of use of linear pulse electromechanical converters of induction, electrodynamics and electromagnetic types as shockpower and accelerating devices; – to implement in the COMSOL Multiphysics software environment a mathematical model of a linear pulse electromechanical converter of multi-core configuration, which takes into account the interconnected electrical, magnetic, mechanical and thermal processes and nonlinear magnetic and thermophysical dependences; – to analyze the electromechanical characteristics of linear pulse electromechanical converters of multicore configurations and to evaluate their efficiency with the help of a complex criterion; – to establish the influence of the shape of the excitation current on the efficiency of linear pulse electromechanical transducers of multicore configurations; – to conduct experimental studies of linear pulse electromechanical transducers, to propose and test models of electromagnetic catapult for unmanned aerial vehicle, magnetic pulse press for ceramic powder materials, electromechanical device for discharging ice and snow deposits from the transmission line wire and transmission line. Object of research – electromechanical processes and indicators of linear pulse electromechanical converters of multicore configurations. Subject of research – linear pulse electromechanical converters of multicore configurations of power and speed purpose. Research methods. Mathematical modeling of electromagnetic, mechanical and thermophysical processes in linear pulse electromechanical converters of pulse action was used to solve the tasks to analyze the electromechanical characteristics and establish the influence of the shape of the excitation current on the efficiency of the converters. Experimental studies of linear pulse electromechanical transducers of multicore configuration were performed on experimental stands, which allowed to test device models. The following scientific results are obtained in the work: – the classification of linear pulse electromechanical converters of multicore configurations, which include ferromagnetic, coil and continuous conductive armature, was further developed; – the mathematical model of the linear pulse electromechanical converter due to inclusion of the ferromagnetic, coil and continuous electrically conductive anchors which interact with a mobile anchor is improved. The mathematical model, which is implemented in the COMSOL Multiphysics software environment, contains interconnected electrical, magnetic, mechanical and thermal processes and takes into account magnetic and thermophysical nonlinear dependencies; – for the first time the peculiarities of the course of electromagnetic processes are established and the electrical, magnetic and power indicators of linear pulse electromechanical converters of multi-core configurations of power purpose are determined. It is shown that almost all converters of multi-arc configurations provide an increase in the amplitude and magnitude of the pulse of electrodynamics forces in comparison with the converter, which has one continuous conductive armature; – for the first time the influence of geometrical parameters of movable and fixed electrically conductive armatures that interact with the movable inductor was established, which allowed to increase the speed indicators of the linear pulse electromechanical converter; – for the first time it is established that when excited by oscillatingattenuating, aperiodic and aperiodic with feeding forms of current in converters of multicore configurations the magnitude of the electrodynamics force pulse increases in comparison with the converter having one continuous electrically conductive armature. The dissertation work was performed at the National Technical University "Kharkiv Polytechnic Institute" and is part of the research work of the Department of General Electrical Engineering. The work was carried out on the basis of financing by state budget topics: "Development of means of increasing the efficiency of linear shock electromechanical accelerators and power devices" (DR №0115U000522), "Improvement of technical systems and devices by means of impulse electromechanical converters. (DR № 0117U004881), the contractual theme "Development and research of high-speed electrodynamics actuator" (at the expense of LLC "TETRA, Ltd", Kharkiv), and the initiative theme "Modern problems and prospects for the development of electrotechnical devices and systems" (DR №0119U002551) where the author was a co-author.

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.09.01 "Електричні машини й апарати" (14 – Електрична інженерія) – Національний технічний університет "Харківський політехнічний інститут", м. Харків, 2020 р. Дисертаційна робота присвячена удосконаленню лінійних імпульсних електромеханічних перетворювачів силового та швидкісного призначення за рахунок використання декількох якорів, що взаємодіють з обмоткою індуктора. В дисертаційній роботі проведено аналіз конструкцій та сфер використання лінійних імпульсних електромеханічних перетворювачів індукційного, електромагнітного та електродинамічного типів в якості ударно-силових та прискорювальних пристроїв. Реалізовано в програмному середовищі COMSOL Multiphysics математичну модель лінійного імпульсного електромеханічного перетворювача мультиякірної конфігурації, яка враховує взаємопов’язані електричні, магнітні, механічні і теплові процеси, нелінійні магнітні та теплофізичні залежності. Розроблено класифікацію електромеханічних перетворювачів, які включають феромагнітний, котушковий та суцільний електропровідний якоря. Встановлено особливості протікання електромагнітних процесів та визначені електричні, магнітні та силові показники електромеханічних мультиякірних конфігурацій. Запропоновано комплексний критерій оцінювання ефективності, за допомогою якого проведено порівняльний аналіз перетворювачів мультиякірних конфігурацій з перетворювачами, що мають один якір. Встановлено вплив форми струму збудження на ефективність перетворювачів мультиякірних конфігурацій. Проведено експериментальні дослідження електромеханічних перетворювачів силового та швидкісного призначення з одночасним вимірюванням електричних, магнітних механічних та теплових параметрів. На базі електромеханічних перетворювачів мультиякірних конфігурацій розроблено оригінальні конструкції та випробувано моделі електромагнітної катапульти для БПЛА, магнітно-імпульсного пресу для керамічних порошкових матеріалів, електромеханічного пристрою для скидання ожеледних і снігових відкладень з проводу лінії електропередачі та пристрою для знищення інформації на твердотільному цифровому SSD накопичувачі.
The dissertation for the degree of Candidate of Technical Sciences in the specialty 05.09.01 “Electric machines and apparatus” (14 - Electrical Engineering) - National Technical University “Kharkov Polytechnic Institute”, Kharkov, 2020. The dissertation is devoted to the improvement of linear pulsed electromechanical converters due to multi-dia configurations. In the dissertation work the analysis of designs and spheres of use of linear pulse electromechanical converters of induction, electromagnetic and electrodynamic type as shock-power and accelerating devices is carried out. Developed and implemented in the COMSOL Multiphysics software environment, a mathematical model of linear pulse electromechanical converters multi-core configuration, which takes into account the interconnected electrical, magnetic, mechanical and thermal processes, nonlinear magnetic and thermophysical dependences. The classification of electromechanical converters which includes ferromagnetic, coil and massive electrically conductive anchors is developed. The peculiarities of the course of electromagnetic processes are established and the electrical, magnetic and power indicators of electromechanical converters of multi-core configurations are determined. A complex criterion for evaluating the efficiency is proposed, by means of which a comparative analysis of electromechanical converters of multicore configurations with electromechanical converters having one anchor is carried out. The influence of the form of excitation current on the efficiency of electromechanical converters of multicore configurations is established. The method is developed and experimental researches of electromechanical converters of power and speed appointment with simultaneous measurement of electric, mechanical and thermal parameters are carried out. On the basis of electromechanical converters multi-core configurations, original designs of electromagnetic catapult models for UAVs, magnetic-pulse press for ceramic powder materials and electromechanical device for discharge of ice and snow deposits from the power line wire were developed and tested.

The embedded portion of a mooring line plays an important role for efficient and economic design of an overall mooring system. This paper presents a methodology for numerical simulation of the behaviour of an embedded anchor chain as it cuts through the soil, focusing on the tensioning of a catenary mooring. The Coupled Eulerian–Lagrangian (CEL) approach within ABAQUS is used to capture the interaction between the embedded chain (Lagrangian structure) and the soil (Eulerian material). The anchor chain is simulated by a series of rigid cylindrical segments connected together by LINK connectors. Before analysing the global behaviour of an embedded chain, a calibration exercise is undertaken where a straight multi-link portion of the chain is displaced normally and axially in soil. The resulting normal and frictional resistances (per unit length) are compared with those adopted in general practice, in order to calibrate the relationship between the diameter of the cylindrical segments and the bar diameter of the chain. After that, the tensioning process of an anchor chain is simulated, starting from an initial configuration with a 9 m length embedded vertically (attached to a fixed padeye), with the remaining length lying on the seabed. Horizontal tensioning of the chain causes it to cut through the soil until it forms an inverse catenary with an angle of just under 35 degrees to the horizontal at the padeye (and zero degrees at the mudline). The loading curve, and also the inverse catenary profile of the chain for different angles at the padeye, are shown to agree well with the Neubecker-Randolph closed-form analytical solution. However, the ratio of the tensions at the padeye and the mudline from the CEL results differs significantly from the analytical solution. Insights from the CEL results indicate that this is because the frictional soil resistance is not fully mobilised, particularly for the portion of the chain in the stronger soil at depth, near the padeye, where the axial displacements are small. This result has significant implications for the geotechnical design of anchoring systems that involve a (nominally) fixed padeye. The simulation methodology also has considerable potential for exploring the creation of an open trench adjacent to a fixed anchor due to monotonic and cyclic perturbations of the anchor chain.

Designs for offshore structures that will be deployed in arctic regions have to consider ice forces, which can be the governing design load. In shallow-water areas (< ∼100 m), fixed bottom caisson designs and artificial islands usually offer the best solutions. In deeper water, however, moored floating systems such as the ship-shaped Floating Production Unit (FPU), the Spar and the Single Column Floater (SCF™) are practical solutions. Even in shallower water where earthquakes are a threat, a moored floater can be a better option because of its ability to avoid seismic effects of the quake due to its suspension in the water above the sea floor. It is estimated that about 30% of the remaining oil and gas reserves lie in the arctic regions of the world. Special care has to be taken to design offshore platforms to survive these extreme arctic environments. Along with severe environmental conditions, there is a possibility of icebergs and multi-year ice sheets as well. A practical solution is to remove the floating structure in case of the expected loads on the structure exceed the maximum design loads. The platform can be brought back to location after the extreme environmental condition has passed. This paper describes a design for a disconnectable mooring system that comprises of external fairleads, submerged chain locker boxes and diverter units along with quick release mechanism and a single handling winch for each group of lines. The system works in tandem with the rig’s ROV and an anchor handling tugboat when connecting the system, while disconnection is automatic without any external assistance other than an emergency release signal. The paper provides the rationale for selecting this configuration based on its strength, redundancy requirements, quick disconnectable ability, without interfering with normal operation and presents a range of applications for this design.

The installations of sub-sea equipments are very complex operations, requiring previous analysis in order to define the correct procedure and the environmental “window” for a safe operation. This paper addresses the installations of a Mid Water Arch (MWA) that consists of a structure to provide risers support. Connecting the risers to the MWA largely eliminates the dynamic forces that would otherwise cause friction and fatigue. Such structure is composed by the riser guides and several buoyancy tanks. It is kept in the water by means of tethers connected to an anchor. The MWA is to be installed 42m from the seabed. The installation procedure has several steps evolving the launching of each component of the MWA (anchor, main structure and the tethers). A tug boat with an A-frame is used during the whole launching, and an assisting vessel is required to keep the buoy away from the tether and the launching cable. The presence of exciting waves induces oscillatory motions in the whole system, and may cause large dynamic forces in the cables and tethers. Due to the complexity of the multi-body system, a comprehensive numerical and experimental analysis was then carried out in order to dimensioning the launching cables and to define the limit environmental condition. The numerical analysis was carried out in the Numerical Offshore Tank (TPN), a multi-processor offshore system simulator that considers the 6 DOF of each body and all environmental forces acting in them. The lines are modeled by finite-element method. Furthermore, a full set of small-scale experiments were carried out at the State of Sa˜o Paulo Technological Research Institute (IPT) towing tank, considering the system excited by a sinusoidal motion at the top, emulating the wave excitation. Comparisons between numerical and experimental results were performed, with good adherence between them. The validated numerical simulator was then used to make predictions of the behavior of the systems during the installation, considering several environmental conditions and configurations.

In this paper a dynamic optimization methodology for designing a passive automotive damper is proposed. The methodology proposes to state the design problem as a dynamic optimization one by considering the nonlinear dynamic interactions between the damper and the other elements of the suspension system, emphasizing geometry, dimensional and movement constraints. In order to obtain realistic simulations of the suspension, a link between a Computer-Aided Engineering Model (CAEM) and a multi-objective dynamic optimization algorithm is developed. As design objectives we consider the vehicle safety and the passenger comfort which are represented by the contact area of the tire and the vibrations of the cockpit respectively. The damper is optimized by stating a set of physical variables that determine the stiffness and damping coefficients as independent variables for the dynamic optimization problem, they include the spring helix diameter, the spring wire diameter, the oil physical characteristics and the bleed orifice diameters among others. The optimization algorithm that we use to solve the problem at hand is a multi-objective evolutive optimization algorithm. For this purpose we developed a parameterized model of the damper which is used to link the CAE tools and the optimization software, thus enabling fitness evaluations during the dynamic optimization process. By selecting the physical characteristics of the damper as design variables instead of the typical stiffness and damping coefficients, it is possible to consider important design constrains as the damper size, movement limitations and anchor points. As result of the proposed methodology a set of blueprints of non dominated Pareto configurations of the damper are provided to the decision maker.

Successful modeling of a turbomachine stage requires attention to many details, including a realistic understanding of the inlet flow field. Various levels of modeling, from 1-D to 3-D viscous, plus various levels of measurement, from a simple inlet shroud pressure tap to complex inlet surveys, are considered in design and development work. In this study, a careful review is made of measurement and calculation options for inlet modeling. Historical practice places a static pressure tap on the shroud just upstream of the impeller leading edge for experimental characterization of centrifugal turbomachines. Previously developed statistics based meanline models rely in part on this measured data. However, the location of the tap may be vulnerable to high gradients which would decrease the dependability of the developed models. Computational Fluid Dynamics (CFD) and Multi-Stream Tube (MST) analyses were performed to test the appropriateness of the historically placed static pressure tap location and to characterize the inlet flow of typical radial flow turbomachines. Eleven ConceptsNREC machines were chosen for investigation to provide a wide variety of inlet geometric and flow conditions. The results derived from the CFD and MST analyses suggest that the historically placed static pressure tap location is an inappropriate anchor point for model development. While the focus of this work is not intended to reveal why the inlet behaves as it does, it does reveal that for a wide variety of inlet configurations and impeller sizes, the presumed inlet tap location should no longer be used in experimental work. Steep gradients in the static pressure indicate that a relatively minor movement of the static pressure tap would significantly alter the experimental measurements and generate noise in statistical modeling. While large variations in the pressure field are apparent near the impeller leading edge for all machines considered, the study results show that the flow field is uniform and very predictable when well upstream of the impeller leading edge. A point approximately 3 blade heights upstream from the impeller leading edge appears to be a sound location to anchor 1-D meanline model development, as well as for future experimental investigation.