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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

“Friends, Partners, Allies” at a Crossroad : A comparative analysis of Canada, the United States, and Islamic State-affiliated citizen repatriation from Northeast Syria

Wenstrup, Kaileigh January 2023 (has links)
Since the 2019 territorial defeat of the Islamic State (IS) in northeastern Syria, thousands of foreign nationals affiliated with the Islamic militant group have been detained in refugee camps and prisons in the region - the humanitarian conditions of which have come under increased scrutiny. As a result, the repatriation of these individuals has become a contentious migration-related policy issue and has led to diverse state responses. In the North American context, there is a striking contrast between Canada’s ‘passive’ approach and the United States’ ‘active’ role in these repatriation efforts. Through a comparative critical discourse analysis (CDA) using Fairclough’s methodological three-step framework and Balzacq’s sociological securitization theory, the public rationale of Canadian-American policy diversion is explored. As a result, this study contributes new knowledge to the field, providing unique insights on how and why two closely-allied countries justify their engagement with IS- affiliated citizens in fundamentally different ways.
102

Machine Learning for State Estimation in Fighter Aircraft / Maskininlärning för tillståndsestimering i stridsflygplan

Boivie, Axel January 2023 (has links)
This thesis presents an estimator to assist or replace a fighter aircraft’s air datasystem (ADS). The estimator is based on machine learning and LSTM neuralnetworks and uses the statistical correlation between states to estimate the angleof attack, angle of sideslip and Mach number using only the internal sensorsof the aircraft. The model is trained and extensively tested on a fighter jetsimulation model and shows promising results. The methodology and accuracyof the estimator are discussed, together with how a real-world implementationwould work. The estimators presented should act as a proof of concept of thepower of neural networks in state estimation, whilst the report discusses theirstrengths and weaknesses. The estimators can estimate the three targets wellin a vast envelope of altitudes, speeds, winds and manoeuvres. However, thetechnology is quite far from real-world implementation as it lacks transparencybut shows promising potential for future development. / Det här examensarbetet presenterar en estimator för att hjälpa eller ersätta ettstridsflygplans luftdatasystem (ADS). Estimatorn är baserad på maskininlärningoch LSTM neurala nätverk och använder statistisk korrelation mellan tillstånd föratt uppskatta anfallsvinkeln, sidglidningsvinkel och Mach-tal endast med hjälpav flygplanets interna sensorer. Modellen är tränad och utförligt testad på ensimuleringsmodell för stridsflygplan och visar lovande resultat. Estimatornsmetodik och noggrannhet diskuteras, tillsammans med hur en implementeringi verkligheten skulle fungera. De presenterade estimatorerna bör fungera somett “proof of concept” för kraften hos neurala nätverk för tillståndsuppskattning,medan rapporten diskuterar deras styrkor och svagheter. Estimatorerna kanuppskatta de tre tillstånden väl i ett stort spektra av altituder, hastigheter, vindaroch manövrar. Tekniken är dock ganska långt ifrån en verklig implementeringeftersom den saknar transparens, men visar lovande potential för framtidautveckling.
103

Calculation of the actual cost of engine maintenance

Ezik, Oguz. January 2003 (has links)
Thesis (M.S.)--Air Force Institute of Technology, 2003. / Title from title screen (viewed July 1, 2004). "March 2003." Vita. "AFIT/GOR/ENS/03-06." "ADA412960"--URL. Includes bibliographical references (p. 87-90). Also issued in paper format.
104

A systematic approach to design for lifelong aircraft evolution

Lim, Dongwook 06 April 2009 (has links)
Modern aerospace systems rely heavily on legacy platforms and their derivatives. Historical examples show that after a vehicle design is frozen and delivered to a customer, successive upgrades are often made to fulfill changing requirements. Current practices of adapting to emerging needs with derivative designs, retrofits, and upgrades are often reactive and ad-hoc, resulting in performance and cost penalties. Recent DoD acquisition policies have addressed this problem by establishing a general paradigm for design for lifelong evolution. However, there is a need for a unified, practical design approach that considers the lifetime evolution of an aircraft concept by incorporating future requirements and technologies. This research proposes a systematic approach with which the decision makers can evaluate the value and risk of a new aircraft development program, including potential derivative development opportunities. The proposed Evaluation of Lifelong Vehicle Evolution (EvoLVE) method is a two- or multi-stage representation of the aircraft design process that accommodates initial development phases as well as follow-on phases. One of the key elements of this method is the Stochastic Programming with Recourse (SPR) technique, which accounts for uncertainties associated with future requirements. The remedial approach of SPR in its two distinctive problem-solving steps is well suited to aircraft design problems where derivatives, retrofits, and upgrades have been used to fix designs that were once but no longer optimal. The solution approach of SPR is complemented by the Risk-Averse Strategy Selection (RASS) technique to gauge risk associated with vehicle evolution options. In the absence of a full description of the random space, a scenario-based approach captures the randomness with a few probable scenarios and reveals implications of different future events. Last, an interactive framework for decision-making support allows simultaneous navigation of the current and future design space with a greater degree of freedom. A cantilevered beam design problem was set up and solved using the SPR technique to showcase its application to an engineering design setting. The full EvoLVE method was conducted on a notional multi-role fighter based on the F/A-18 Hornet.
105

An Integrated Estimation-Guidance Approach for Seeker-less Interceptors

Saroj Kumar, G January 2015 (has links) (PDF)
In this thesis, the problem of intercepting highly manoeuvrable threats using seeker-less interceptors that operate in the command guidance mode, is addressed. These systems are more prone to estimation errors than standard seeker-based systems. Several non-linear and optimal estimation and guidance concepts are presented in this thesis for interception of randomly maneuvering targets by seeker-less interceptors. The key contributions of the thesis can be broadly categorized into six groups, namely (i) an optimal selection of bank of lters in interactive multiple model (IMM) scheme to cater to various maneuvers that are expected during the end-game, (ii) an innovative algorithm to reduce chattering phenomenon and formulate effective guidance algorithm based on 'differential game guidance law' (modi ed DGL), (iii) IMM/DGL and IMM/modified DGL based integrated estimation/guidance (IEG) strategy, (iv) sensitivity and robustness analysis of Kalman lters and ne tuning of lters in filter bank using innovation covariance, (v) Performance of tuned IMM/PN, tuned IMM/DGL and tuned IMM/modi ed DGL against various target maneuvers, (vi) Performance comparison with realistic missile model. An innovative generalized state estimation formulation has been proposed in this the-sis for accurately estimating the states of incoming high speed randomly maneuvering targets. The IMM scheme and an optimal selection of lters, to cater to various maneu-vers that are expected during the end-game, is described in detail. The key advantage of this formulation is that it is generic and can capture evasive target maneuver as well as straight moving targets in a uni ed framework without any change of target model and tuning parameters. In this thesis, a game optimal guidance law is described in detail for 2D and 3D engagements. The performance of the differential game based guidance law (DGL) is compared with conventional Proportional Navigation (PN) guidance law, especially for 3D interception scenarios. An innovative chatter removal algorithm is introduced by modifying the differential game based guidance law (modified DGL). In this algorithm, chattering is reduced to the maximum extent possible by introducing a boundary layer around the switching surface and using a continuous control within the boundary layer. The thesis presents performance of the modified DGL algorithm against PN and DGL, through a comparison of miss distances and achieved accelerations. Simulation results are also presented for varying fiight path angle errors. Apart from the guidance logic, two novel ideas have been presented following the evolving "integrated estimation and guidance" philosophy. In the rst approach, an in-tegrated estimation/guidance (IEG) algorithm that integrates IMM estimator with DGL law (IMM/DGL), is proposed for seeker-less interception. In this interception scenario, the target performs an evasive bang-bang maneuver, while the sensor has noisy measure-ments and the interceptor is subject to an acceleration bound. The guidance parameters (i.e., the lateral acceleration commands) are computed with the help of zero e ort miss distance. The thesis presents the performance of the IEG algorithm against combined IMM with PN (IMM/PN), through a comparison of miss distances. In the second ap-proach, a novel modi ed IEG algorithm composed of IMM estimator and modi ed DGL guidance law is introduced to eliminate the chattering phenomenon. Results from both of these integrated approaches are quite promising. Monte Carlo simulation results re-veal that modi ed IEG algorithm achieves better homing performance, even if the target maneuver model is unknown to the estimator. These results and their analysis o er an insight to the interception process and the proposed algorithms. The selection of lter tuning parameters puts forward a major challenge for scien-tists and engineers. Two recently developed metrics, based on innovation covariance, are incorporated for determining the filter tuning parameters. For predicting the proper combination of the lter tuning parameters, the metrics are evaluated for a 3D interception problem. A detailed sensitivity and robustness analysis is carried out for each type of Kalman lters. Optimal and tuned Kalman lters are selected in the IMM con guration to cater to various maneuvers that are expected during the end-game. In the interception scenario examined in this thesis, the target performs various types of maneuvers, while the sensor has noisy measurements and the interceptor is subject to acceleration bound. The tuned IMM serves as a basis for synthesis of e cient lters for tracking maneuvering targets and reducing estimation errors. A numerical study is provided which demonstrates the performance and viability of tuned IMM/modi ed DGL based modi ed IEG strategy. In this thesis, comparison is also performed between tuned IMM/PN, tuned IMM/DGL and tuned IMM/modi ed DGL in integrated estimation/guidance scheme. The results are illustrated by an extensive Monte Carlo simulation study in the presence of estimation errors. Simulation results are also presented for end game maneuvers and varying light path angle errors . Numerical simulations to study the aerodynamic e ects on integrated estimation/ guidance structure and its e ect on performance of guidance laws are presented. A detailed comparison is also performed between tuned IMM/PN, tuned IMM/DGL and tuned IMM/modi ed DGL in integrated estimation/guidance scheme with realistically modelled missile against various target maneuvers. Though the time taken to intercept is higher when a realistic model is considered, the integrated estimation/guidance law still performs better. The miss distance is observed to be similar to the one obtained by considering simpli ed kinematic models.
106

Human-centred automation : with application to the fighter aircraft domain

Helldin, Tove January 2012 (has links)
The working situation of fighter pilots is often very challenging. The pilots are requested to perform their tasks and make decisions in situations characterised by time-pressure, huge amounts of data and high workload, knowing that wrong decisions might result in fatal consequences. To aid the pilots, several automatic support systems have been implemented in modern fighter aircraft and will continue to be implemented in pace with technological advancements and new demands posed on the pilots. For example, innovations within the information fusion (IF) domain have made it possible to fuse large amounts of data, stemming from different sensors, databases etc., to create a better foundation for making decisions and act than would have been possible if the information sources had been used separately. However, there are both positive and negative effects of automation, such as decreased workload and improved situation awareness on the one hand, but skill degradation and complacent behaviour on the other. To avoid the possible negative consequences of automation, while at the same time ameliorating the positive ones, a human-centred automation (HCA) approach to system design has been proposed as a way of optimizing the collaboration between the human and the machine. As a design approach, HCA stresses the importance of a cooperative human-machine relationship, where the operator is kept in the automation loop. However, how to introduce HCA within the fighter aircraft domain as well as its implications for the interface and automation design of support systems within the field has not been investigated. This thesis investigates the implications of introducing HCA into the fighter aircraft domain. Through literature surveys and empirical investigations, general and domain specific HCA guidelines have been identified. These advocate, for example, that an indication of the reliability of the information and the recommendations provided by the different aircraft support systems must be given as well as that support for appropriate updates of the pilots’ individual and team awareness of the situation must be provided. A demonstrator, mirroring some of the identified guidelines, has been implemented and used to evaluate the guidelines together with system developers within the domain. The evaluation indicated that system developers of modern fighter aircraft implicitly incorporate many of the identified HCA guidelines when designing. However, the evaluation further revealed that to explicitly incorporate these guidelines into the development approach, preferably through the development of a domain specific style guide, would aid the system developers design automated support systems that provide appropriate support for the pilots. The results presented in this thesis are expected to aid developers of modern fighter aircraft support systems by incorporating HCA into the traditional simulator-based design (SBD) approach. This approach is frequently used within the field and stresses early and frequent user-involvement when designing, in which complementary HCA evaluations could be performed to further improve the support systems implemented from an automation perspective. Furthermore, it is expected that the results presented in this thesis will contribute to the research regarding how to incorporate the human operator in the information fusion processes, which has been recognised as a research gap within the IF field. Thus, a further contribution of this thesis is the suggestion of how the HCA development approach could be of aid when improving the interaction between the operator and the automated fusion system. / Arbetssituationen för stridspiloter är ofta mycket utmanande. Piloterna måste utföra sina uppgifter och fatta beslut i stressiga situationer med stora informationsmängder och hög arbetsbörda, samtidigt som val av fel beslut kan leda till allvarliga konsekvenser. För att hjälpa piloterna har flera automatiska stödsystem implementerats i moderna stridsflygplan. Denna trend kommer att fortsätta i takt med nya tekniska framgångar och nya krav som ställs på piloterna. Forskning inom informationsfusion (IF) har bland annat gjort det möjligt att fusionera stora mängder data som härstammar från olika sensorer, databaser m.m. för att på så sätt skapa en bättre grund för att fatta beslut och agera än vad som hade varit möjligt om informationskällorna hade använts separat. Dock har både positiva och negativa effekter av automatisering rapporterats, såsom minskad arbetsbörda och förbättrad situationsuppfattning men även försämrad pilotprestation till följd av att de automatiska systemens prestanda inte övervakas. För att undvika negativa effekter av automation samtidigt som de positiva effekterna stärks har den så kallade människo centrerade automationen (HCA) lyfts fram som en möjlig väg att designa system där samverkan mellan automationen och den mänskliga operatören optimeras. Som en designapproach fokuserar HCA på viken av en samverkande människamaskin relation, där operatören hålls kvar i automatiseringsloopen. Men hur HCA kan introduceras inom stridsflygdomänen och dess implikationer för gränssnitts- och automationsdesign av stödsystem inom domänen har inte undersökts. Denna licentiatavhandling undersöker möjliga implikationer av att introducera HCA inom stridsflygdomänen. Genom litteraturundersökningar och empiriska studier har generalla och domänspecifika HCA riktlinjer identifierats, såsom att piloterna måste erbjudas en indikation angående tillförlitligheten hos den information och de rekommendationer som de olika implementerade stödsystemen i flygplanet har genererat, samt att stöd för att uppdatera piloternas individuella och gemensamma uppfattning av situationen måste ges. En demonstrator, som återspeglar några av de identifierade HCA riktlinjerna, har implementerats och använts för att utvärdera riktlinjerna tillsammans med systemutvecklare inom domänen. Denna utvärdering påvisade att systemutvecklare inom stridsflygdomänen implicit använder sig av många av de identifierade HCA riktlinjerna under designprocessen, men att explicit inkludera dessa i en domänspecifik design guide skulle kunna hjälpa dem att designa automatiska system som erbjuder lämpligt stöd för piloterna. De resultat som presenteras i denna licentiatavhandling förväntas kunna hjälpa utvecklare av moderna stridsflygsystem genom att inkludera HCA i den traditionella simulator-baserade designapproachen (SBD). Denna approach används flitigt inom området och fokuserar på tidigt och återkommande användardeltagande vid designarbetet, där komplementära HCA utvärderingar skulle kunna genomföras för att förbättra de stödsystem som implementeras från ett automationsperspektiv. Det förväntas även att de resultat som presenteras i denna avhandling kommer att bidra till forskningen kring hur operatörer kan påverka fusionsprocessen, vilket har identifierats som ett område där mer forskning behövs inom IF området. Ytterligare ett bidrag av denna avhandling är därför det förslag som ges på hur HCA utvecklingsprocessen skulle kunna användas för att förbättra interaktionen mellan operatören och det automatiska fusionssystemet.
107

Вовлечение молодежи в деятельность студенческих отрядов: современные подходы : магистерская диссертация / Involvement of young people in the activities of student groups: modern approaches

Зинятова, М. А., Zinyatova, M. A. January 2022 (has links)
Формирование и развитие любого государства связано с интеграцией молодежи в общественно-политическую и социокультурную деятельность страны. Студенческая часть является группой с особыми условиями труда, проведения досуга, системой ценностей и интересов. Актуальность исследования заключается в уменьшении численности кандидатов в движение студенческих отрядов в течение последних пяти лет в результате снижения мотивации у студентов идти в движение студенческих отрядов. В течение последних 5 лет студенческие отряды УрФУ с каждым годом перестают пользоваться популярностью, всё меньше талантливых ребят идут в движение, а многим оно кажется уже устаревшим, тем самым снижается качество работы и престиж организации. Теоретической основой диссертационного исследования являются труды отечественных и зарубежных ученых, изучающих потенциал движения студенческих отрядов и их влияние на современных студентов. Проблема исследования заключается в необходимости корректировки подходов вовлечения молодежи в деятельность студенческих отрядов. Гипотеза исследования базируется на предположении о том, что если в деятельности штаба студенческих отрядов будет реализована программа, включающая современные формы рекламы и агитация движения студенческих отрядов, обучение лидеров студенческих отрядов основам вовлечения молодежи, изменения в организационном управлении движением студенческих отрядов, комплект мероприятий по повышению имиджа студенческих отрядов, то можно будет наблюдать увеличение численности кандидатов в движении. / The formation and development of any state is connected with the integration of young people into the socio-political and socio-cultural activities of the country. The student part is a group with special working conditions, leisure activities, a system of values and interests. The relevance of the study lies in the decrease in the number of candidates for the movement of student detachments over the past five years as a result of a decrease in the motivation of students to join the movement of student detachments. Over the past 5 years, UrFU student teams have been losing popularity every year, fewer and fewer talented guys are starting to move, and for many it seems outdated, thereby reducing the quality of work and the prestige of the organization. The theoretical basis of the dissertation research is the works of domestic and foreign scientists studying the potential of the movement of student groups and their impact on modern students. The problem of the study is the need to adjust the approaches of involving young people in the activities of student groups. The hypothesis of the study is based on the assumption that if a program is implemented in the activities of the headquarters of student detachments, including modern forms of advertising and agitation of the movement of student detachments, training of leaders of student detachments on the basics of youth involvement, changes in the organizational management of the movement of student detachments, a set of measures to improve the image of student detachments, it will be possible to observe an increase in the number of candidates in motion.
108

Формирование проектной культуры бойцов студенческих отрядов : магистерская диссертация / Formation of project culture of fighters of student detachments

Кондюрин, С. Д., Kondyurin, S. D. January 2023 (has links)
Актуальность исследования заключается в том, что современная молодежная политика реализуется с учетом проектного подхода. Студенческие отряды являются объектом молодежной политики, содействуют в создание активной гражданской позиции и содействуют в самореализации молодых людей. В работе определены перечень навыков, которые лежат в основе проектной культуры. Представлен исследовательский дизайн при разработке программы по формированию проектной культуры у бойцов студенческих отрядов. Проведен анализ научной литературы по тематике данного исследования, описан портрет бойца студенческих отрядов УрФУ. Предложено определение «Проектная культура бойца студенческого отряда». Проведен SWOT – анализ деятельности движения студенческих отрядов. Предложены механизмы по формированию проектной культуры в среде студенческих отрядов. В работе представлена программа по формированию проектной культуры у бойцов студенческих отрядов Уральского федерального университета. Программа состоит из 3-х блоков: информационный блок, интерактивный блок, состоящий из четырех тренингов, проектный модуль, включающий «Творческую лабораторию - проектная культура студенческого отряда». Приводятся результаты тестирования программы по формированию проектной культуры у бойцов студенческих отрядов. Делается вывод что механизмы, реализуемые в программе по формированию проектной культуры, являются эффективными и могут быть реализованы не только в деятельности органов студенческого самоуправления, но и в образовательной среде вуза. / The relevance of the research lies in the fact that modern youth policy is implemented considering the project approach. Student groups are the object of youth policy, contribute to the creation of an active civic position and contribute to the self-realization of young people. The paper defines a list of skills that underlie the project culture. A research design is presented when developing a program for the formation of a project culture among the fighters of student detachments. The analysis of scientific literature about this study is carried out, the portrait of a fighter of UrFU student detachments is described. The definition of "Project culture of a student squad fighter" is proposed. A SWOT analysis of the activity of the movement of student detachments was carried out. Mechanisms for the formation of project culture among student groups are proposed. The paper presents a program for the formation of project culture among the fighters of student detachments of the Ural Federal University. The program consists of 3 blocks: an information block, an interactive block consisting of four trainings, a project module including a "Creative laboratory - project culture of the student team". The results of testing the program for the formation of project culture among the fighters of student detachments are given. It is concluded that the mechanisms implemented in the program for the formation of project culture are effective and can be implemented not only in the activities of student self-government bodies, but also in the educational environment of the university.
109

The Rationality of Nonconformity: the United States decision to refuse ratification of Protocol I Additional to the Geneva Conventions of 1949

Childers, Rex A. 08 August 2008 (has links)
No description available.
110

Multi Purpose Electro-Hydraulic Converter for More Electrical Power : A Case Study of Using Electro-Hydraulic Energy Converters in a Fighter Aircraft Application

Allansson, Niklas, Böhlin, Erik January 2024 (has links)
The hydraulic system in a fighter aircraft is not fully utilised during large parts of the flight mission were more electrical power is needed. To better utilise the hydraulic power the current Auxiliary Hydraulic Pump (AHP) and the Emergency Hydraulic Pump (EHP) can be exchanged to an Electro Hydraulic Energy Converter (EHEC). The EHEC has the possibility to provide hydraulic power to the system, but also convert hydraulic power into electric power. The control for such a unit can be implemented in different ways. A literature study was performed to decide a suitable architecture for use in a fighter aircraft application. A simulation model representing the resulting architecture was created. The simulation model was successful in describing the basic behaviour of the hydraulic system, but lacks a realistic representation of hydraulic consumers.  Different control strategies were created and tested on the simulation model with several test scenarios based on real flight data from tests performed on the aircraft. The control strategies were compared and suitable candidates were presented based on their relative performance and compared with the current hydraulic system behaviour. An architecture consisting of a variable displacement pump with over-center capabilities combined with a permanent magnet synchronous machine (PMSM) was decided to be used. A PI-controller with a feedforward on consumer flow was the best performing controller for use in emergency operation of the EHEC. For the case when regenerating electrical power a PI-controller with load pressure feedback is desired initially during start up. When reaching steady state a PI-controller without load pressure feedback is then advantageous.

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