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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.
21

Aircraft Trajectory Optimization with Tactical Constraints

Norsell, Martin January 2004 (has links)
<p>Aircrafttrajectory optimization is traditionally used forminimizing fuel consumption or time when going from one flightstate to another. This thesis presents a possible approach toincorporate tactical constraints in aircraft trajectoryoptimization.</p><p>The stealth technology of today focuses on making thetactics already in use more effective. Since tactics andstealth are closely interrelated, new and better results may beobtained if both aspects are considered simultaneously. Simplyreducing the radar cross section area in some directionswithout considering tactical aspects may result in little, ifany, improvement.</p><p>Flight tests have been performed in cooperation withEricsson Microwave Systems and the Swedish Air Force FlightAcademy. The aircraft used was the subsonic jet trainer Saab105, designated SK60 by the Swedish Air Force. The results showa decrease of 40% in the time interval between the instant theaircraft was first detected until it could pass above the radarstation. This corresponds to a reduced radar cross section(RCS) in the direction from the aircraft to the radar of almost90%, if classical RCS reduction techniques would have beenapplied.</p><p>If a modern aircraft with stealth properties would be used,the proposed methodology is believed to increase the possibleimprovements further. This is because the variation of themagnitude of RCS in different directions is greater for a shapeoptimized aircraft, which is the property exploited by thedeveloped method.</p><p>The methods presented are indeed an approach utilizing theideas of the network centric warfare (NCW) concept. Themethodology presented depends on accurate information about theadversary, while also providing up-to-date information to theother users in the information network.</p><p>The thesis focuses on aircraft but the methods are generaland may be adapted for missiles, shipsor land vehicles. Theproposed methods are also economically viable since they areuseful for existing platforms without costly modifications. Themethods presented are not limited to radar threats only. Thereasons for using radar in this thesis are the availablenon-classified data and that radar is known to pose a majorthreat against aircraft.</p>
22

An experimental investigation of a crossover concept for high accuracy indoor positioning systems

Lind, Andreas January 2015 (has links)
To know your whereabouts is important and sometimes exact position is the determinant of success or not. Since the launch of the USA made Global Positioning System (GPS) in the late 1970s, global tracking has been available both for military and civilian use. Today, satellite based systems like the American GPS, European Galileo and the Russian GLONASS are the standard for basically any navigation or location application. However these systems are limited by the fact that they must have connection with multiple satellites in order to work. This means that satellite dependent systems are very limited in indoor environments. Despite this, there is no standard for indoor positioning systems (IPSs) even close to the satellite dependent systems when it regards distribution and accessibility for use where satellite dependent systems are limited or not working. However, this new age of connectivity provides a number of options for positioning indoors. There are some systems available, but very few of them provide good enough accuracy. This Master thesis evaluates different options for indoor positioning using technologies that are available in smart devices and smart phones, such as Wi-Fi and Bluetooth, and focuses on indoor positioning systems that can provide high accuracy. The current state of the technologies and the possible future for them, considering rising need and interest in indoor positioning systems are covered in this thesis. A selection of technologies and approaches are explored, tested in conditions designed for this purpose and evaluated to highlight their differences in approach, accuracy and usability. In order to achieve the goals of this thesis, a hybrid method of experimental research design and system development is selected as the main research method. The hybrid method is focused on experimental research, and is used to investigate if the accuracy of the positioning data can be affected and improved by tuning independent variables in an IPS. To be able to do this, an application for smart devices, such as android smartphones, is developed. The application developed is the heart of the conceptual crossover IPS (CCIPS), which is named Locantis, that is being developed and used in the experimental stages of this investigation. It is also used to test the hypothesis that a CCIPS could be a valid contender for replacing the established IPSs. The observations show how the accuracy and precision of the location data is affected by change to independent variables in an IPS and how well a CCIPS can meet real time requirement’s. The main conclusion is that changes to independent variables have greater impact on the precision than the accuracy for location data in an IPS and that a CCIPS in many cases are the sensible choice of IPS. / Att veta var du befinner dig är viktigt och ibland är exakt position avgörande för framgång. Sedan lanseringen av amerikanska Global Positioning System (GPS) i slutet av 1970 har global navigation varit tillgängliga för både militärt och civilt bruk. Idag är satellitbaserade system, som det amerikanska GPS, europeiska Galileo och det ryska GLONASS, standard för i princip alla navigering eller platsinformation. Men dessa system är begränsade av det faktum att de måste ha kontakt med flera satelliter för att fungera. Detta innebär att satellitberoende system är mycket begränsad i inomhusmiljöer. Trots detta finns det ingen standard för inomhus positioneringssystem (IPSS) som kan mäta sig med de satellitberoende systemen när det gäller distribution och tillgänglighet. Men denna nya generationens kommunikation ger ett antal alternativ för positionering inomhus. Det finns IPS tillgängliga idag, men väldigt få av dem kan tillhandahålla en hög noggrannhet på positioneringen. Detta examensarbete utvärderar olika alternativ för inomhuspositionering med teknologier som är tillgängliga i smarta enheter och smarta telefoner, som Wi-Fi och Bluetooth, fokus ligger på inomhus positioneringssystem som kan ge hög noggrannhet. Det aktuella läget för dessa teknologier och dess möjliga framtid, med tanke på stigande behov och intresse av inomhus positioneringssystem, behandlas i detta examensarbete. Ett urval av teknologier och metoder utforskas, testas under förhållanden utformade för detta ändamål, och utvärderas för att lyfta fram sina skillnader i tillvägagångssätt, noggrannhet och användbarhet. För att uppnå målen i detta examensarbete har en hybrid metod för experimentell designforskning och systemutveckling valts som huvudsaklig forskningsmetod. Hybridmetoden fokuserar på experimentell forskning och används för att undersöka om positioneringsdatas noggrannhet kan påverkas och förbättras genom att förändra oberoende variabler i ett IPS. För att kunna göra detta har en applikation för smarta enheter, så som Android, utvecklats. Applikationen som utvecklats är hjärtat i det konceptuella kombinations inomhuspositioneringssystem Locantis som utvecklas och används i det experimentella stadiet i denna undersökning. Den används också för att testa hypotesen att en CCIPS kunde vara en giltig kandidat för att ersätta den etablerade IPSer. Observationerna visa hur noggrannhet och precision av positioneringsdata påverkas av förändring på oberoende variabler i ett IPS och hur väl ett CCIPS kan uppfylla realtidskravet talet. Huvudslutsatsen är att förändringar på oberoende variabler har större inverkan på precision än noggrannheten för lokaliseringsuppgifter i en IPS och att ett CCIPS i många fall är det klokt val av IPS.
23

Comando e controle no contexto da digitalização : um estudo com base em modelagem computacional / Command and control in the context of digitization: a study based on computational modeling

Bertol, Frederico Licks January 2018 (has links)
Este trabalho propõe uma discussão em torno dos impactos da digitalização sobre sistemas militares de comando e controle. A hipótese central é que o emprego intensivo de tecnologias digitais está associado a um maior risco de sobrecarga informacional nesses sistemas. Isso se aplica em especial às forças militares que adotaram doutrinas de viés tecnocrático, como a guerra centrada em redes. No primeiro capítulo, discutimos o contexto no qual nosso tema de pesquisa se insere, fazendo uma breve retrospectiva do processo de digitalização e também definindo alguns conceitos-chave. No segundo capítulo, em formato de artigo, apresentamos o modelo computacional que foi desenvolvido para simular o funcionamento de um sistema de comando e controle sob a condição de sobrecarga informacional. O artigo também reúne uma revisão crítica das abordagens sobre comando e controle, com ênfase na literatura sobre guerra centrada em redes. O terceiro e último capítulo traz algumas conclusões sobre o emprego da modelagem computacional como metodologia de pesquisa e o estado atual do debate sobre guerra centrada e redes. / This work proposes a discussion on the impacts of digitization over military command and control systems. The central hypothesis is that the intensive deployment of digital technologies is associated to a greater risk of informational overload in those systems. This applies especially to military forces that have adopted doctrines with a technocratic bias, such as the network-centric warfare. In the first chapter, we discuss the context that encompass our research topic, making a brief retrospective of the process of digitization and defining some key concepts. In the second chapter, in form of article, we present the computational model developed for simulating the operation of a command and control system under the condition of informational overload. The article also contains a critical review on the command and control approaches, with emphasis on the literature about network-centric warfare. The third and last chapter brings out some conclusions regarding the use of computational modeling as a research method and the current state of the debate on network-centric warfare.
24

MINUSMA a příklon OSN k proti-povstaleckým a proti-teroristickým operacím / MINUSMA and the United Nation's Turn to Counter-terrorism and Counter-insurgency

van Oppen Ardanaz, Gabriel January 2019 (has links)
This Master's thesis will focus on the newest trends in the field of United Nations (UN) peacekeeping operations that are moving the organization to unknown territory by deploying in theatres where missions are faced with asymmetric threats. In this regard, the United Nations Multidimensional Integrated Stabilization Mission in Mali (MINUSMA), constituted as a groundbreaking and innovative peacekeeping operation, is spearheading a realignment in peacekeeping that can potentially shape future operations to come, as mandates increasingly reflect roles in areas such as counter-insurgency and counter-terrorism. The core objective of this study will be to analyze why MINUSMA is being forced to go green while studying how it is doing so, reflecting on past experiences from other operations such as the International Stabilization Assistance Force (ISAF) in Afghanistan and the Multi-National Force in Iraq (MNF-I), that have guided changes in MINUSMA's doctrines and capabilities. Gabriel van Oppen Ardanaz
25

En framtida resurs eller ett arv från det förflutna? : en teoriprövande enfallsstudie om nätverksbaserat försvar i Irak

Samor, Adam January 2020 (has links)
The theory of network centric warfare has since its introduction in the early 2000s experienced both a substantial hype and spectacular collapse. Various studies have focused on the theory’s ability to increase mission effectiveness, predominantly within sea and air operations, whilst the domain of land warfare remains largely uncharted. This single case study assesses the theory’s ability to deliver mission effectiveness in ground combat. The case chosen for the study was the U.S. army 3rd Infantry Division and their offensive during the invasion of Iraq 2003. It is concluded that, while a digitalized force, the interoperability within the division was low, effectively excluding definite claims of network centric warfare’s ability to produce mission effectiveness in the land warfare domain. Being one of a few studies on this complex domain, these results warrant for further research. In addition to its findings the study provides an additional tool for how the effects and workings of network centric warfare may be understood and studied in the future.
26

Comparative Assessment of Network-Centric Software Architectures

Krishnamurthy, Likhita 24 July 2006 (has links)
The purpose of this thesis is to characterize, compare and contrast four network-centric software architectures, namely Client-Server Architecture (CSA), Distributed Objects Architecture (DOA), Service-Oriented Architecture (SOA) and Peer-to-Peer Architecture (PPA) and seven associated frameworks consisting of .NET, Java EE, CORBA, DCOM, Web Services, Jini and JXTA with respect to a set of derived criteria. Network-centric systems are gaining in popularity as they have the potential to solve more complex problems than we have been able to in the past. However, with the rise of SOA, Web Services, a set of standards widely used for implementing service-oriented solutions, is being touted as the "silver bullet" to all problems afflicting the software engineering domain with the danger of making other architectures seem obsolete. Thus, there is an urgent need to study the various architectures and frameworks in comparison to each other and understand their relative merits and demerits for building network-centric systems. The architectures studied here were selected on the basis of their fundamentality and generality. The frameworks were chosen on the basis of their popularity and representativeness to build solutions in a particular architecture. The criteria used for comparative assessment are derived from a combination of two approaches — by a close examination of the unique characteristics and requirements of network-centric systems and then by an examination of the constraints and mechanisms present in the architectures and frameworks under consideration that may contribute towards realizing the requirements of network-centric systems. Not all of the criteria are equally relevant for the architectures and frameworks. Some, when relevant, are relevant in a different sense from one architecture (or framework) to another. One of the conclusions that can be drawn from this study is that the different architectures are not completely different from each other. In fact, CSA, DOA and SOA are a natural evolution in that order and share several characteristics. At the same time, significant differences do exist, so it is clearly possible to judge/differentiate one from the other. All three architectures can coexist in a single system or system of systems. However, the advantages of each architecture become apparent only when they are used in their proper scope. At the same time, a sharp difference can be perceived between these three architectures and the peer-to-peer architecture. This is because PPA aims to solve a totally different class of problems than the other three architectures and hence has certain unique characteristics not observed in the others. Further, all of the frameworks have certain unique architectural features and mechanisms not found in the others that contribute towards achieving network-centric quality characteristics. The two broad frameworks, .NET and Java EE offer almost equivalent capabilities and features; what can be achieved in one can be achieved in the other. This thesis deals with the study of all the four architectures and their related frameworks. The criteria used, while fairly comprehensive, are not exhaustive. Variants of the fundamental architectures are not considered. However, system/software architects seeking an understanding of the tradeoffs involved in using the various architectures and frameworks and their subtle nuances should benefit considerably from this work. / Master of Science
27

A Conceptual Framework for Specification of Network-Centric System Architectures

Churbanau, Dzmitry 26 May 2010 (has links)
Software-based system architecture has been recognized as a foundation laying out the underpinnings that are critically important for successful engineering of large-scale complex systems. In recent years, architecting has played a more crucial role in engineering network-centric system of systems. The software paradigm has been shifting from treating software as a product (SaaP) to treating software as a service (SaaS). SaaS is also referred to as the Cloud Computing, where the term "cloud" is used as a metaphor for "network". As the complexity of the architecture of network-centric software-based system of systems has increased, the description of such architecture has posed significant technical challenges. The U.S. Department of Defense (DoD) has developed the DoD Architecture Framework [DoDAF 2009a, DoDAF 2009b] for describing system architectures. IEEE proposes a Recommended Practice for Architectural Description of Software-Intensive Systems [IEEE 2000]. SEI provides high-level guidelines for Documenting Software Architectures [Clements et al 2003]. However, all of the diagrams proposed by DoD, IEEE, and SEI are two-dimensional static graphical and textual representations that do not reveal the dynamic characteristics of a system architecture. This thesis presents a conceptual framework (CF) for specifying the architecture of a network-centric software-based system of systems. The developed CF provides the beginning part of a larger research effort. The main goal of the overall research is to employ the automation-based software paradigm and to automatically generate a visual simulation model of a system architecture, with which experiments can be conducted to assess the dynamic characteristics of that architecture. The CF, developed in the research described herein, enables the automatic generation of a visual simulation model representing a system architecture. The proposed CF is evaluated in half a dozen case studies to demonstrate that it provides the necessary elements for automatic generation of a simulation model as the description of a complex system of systems architecture. / Master of Science
28

Guiding Network-Centrtic Architectural Design: a Style-Based Approach

Chigani, Amine 13 February 2008 (has links)
With the advance of reliable network technology, software development has progressed from traditional, platform-centric software construction to network-centric software evolution. An evidence of this change is largely reflected in the technologies that are supporting the emerging theory of Network-Centric Operations (NCO). Amongst these technologies is software architecture as a software engineering sub-discipline. Although the concepts of network centricity are widely recognized within the software and system engineering communities, no unified characterization of network-centric software systems is unanimously adopted. The state-of-the-practice is characterized by differing interpretations about how we should design and implement this class of systems. In this research, our focus is twofold: 1) Providing a characterization framework to reason about network-centric software systems and 2) introducing one solution approach to designing this class of system based on a new architectural style, the network-centric architectural style. In so doing, we set the stage for the software architecture community to analyze the "fitness of use" of current architectural styles and architecture design practices within this new network-centric paradigm. In addition, we set the stage for our continued research that will address further software engineering challenges pertinent to network-centric software systems, which include capability-based requirements engineering and quality attributes-based design. / Master of Science
29

Situation Awareness: A Network Centric Approach

Ojha, Ananya 19 November 2008 (has links)
Situation (al) awareness (SA) is critical to analyze, predict and perform tasks effectively in a dynamic environment. Many studies on SA have ignored network dynamism and its effect on SA, focusing on simple environments. Many studies involving the network and SA have refrained from attempting to model information space dynamism (i.e. dynamic scenarios which may have more than one probable outcome). Few studies have identified the need for a flexible, robust and overarching framework which could model both the network and information space dynamisms and provide for analysis of different types of networks (heterogeneous/homogeneous) at multiple scales. We utilize the NCOPP (Network Centric Operations Performance & Prediction), a uniform framework with "plug-&-play" capabilities to provide analysis and performance prediction of networked information systems. In this work, we demonstrate the flexibility of the NCOPP framework and its ability to model a hierarchical sensor system satisfactorily. We model the network & information space dynamisms using probability and statistics theory (e.g. Bayesian prediction, probability distribution curves). We model the behavior of entities/nodes involved in the process of sharing information to achieve greatly improved situation awareness about a dynamic environment within hierarchical information network systems. Our behavior model mathematically represents how successful/unsuccessful predictions critically impact the achievement of effective situation awareness. In the behavior model, we tie together the cost of considering predictions which accounts for limited resources and the indirect effect of unsuccessful predictions. We research and show how the NCOPP framework can model real world networked information systems at different levels of granularity. We leverage the framework's capabilities to perform experiments that not only assist in an objective comparison of distributed information filtering and central data processing paradigms but also provide important insights into the effect of network dynamism on the quality and completeness of information in the system. We demonstrate the ability of incorporating key network information, in the process of achieving SA to improve the performance of the system. We exhibit the improvement in performance achieved with inclusion of the network characteristics during dynamic allocation of resources. We were able to show that simple hierarchical filtering (via distributed processing) results in significant reduction in the information in regards to "false alarms" when compared to systems employing central information processing. Experimental results show a direct positive impact in the completeness of SA when information sharing in hierarchical systems is supplemented by network delay information. Overall, we demonstrated the ability of the NCOPP framework to provide meaningful insights into the interactions of key factors involved in operation of networked information systems, with a particular emphasis on SA. / Master of Science
30

A computational approach to achieve situational awareness from limited observations of a complex system

Sherwin, Jason 06 April 2010 (has links)
At the start of the 21st century, the topic of complexity remains a formidable challenge in engineering, science and other aspects of our world. It seems that when disaster strikes it is because some complex and unforeseen interaction causes the unfortunate outcome. Why did the financial system of the world meltdown in 2008-2009? Why are global temperatures on the rise? These questions and other ones like them are difficult to answer because they pertain to contexts that require lengthy descriptions. In other words, these contexts are complex. But we as human beings are able to observe and recognize this thing we call 'complexity'. Furthermore, we recognize that there are certain elements of a context that form a system of complex interactions - i.e., a complex system. Many researchers have even noted similarities between seemingly disparate complex systems. Do sub-atomic systems bear resemblance to weather patterns? Or do human-based economic systems bear resemblance to macroscopic flows? Where do we draw the line in their resemblance? These are the kinds of questions that are asked in complex systems research. And the ability to recognize complexity is not only limited to analytic research. Rather, there are many known examples of humans who, not only observe and recognize but also, operate complex systems. How do they do it? Is there something superhuman about these people or is there something common to human anatomy that makes it possible to fly a plane? - Or to drive a bus? Or to operate a nuclear power plant? Or to play Chopin's etudes on the piano? In each of these examples, a human being operates a complex system of machinery, whether it is a plane, a bus, a nuclear power plant or a piano. What is the common thread running through these abilities? The study of situational awareness (SA) examines how people do these types of remarkable feats. It is not a bottom-up science though because it relies on finding general principles running through a host of varied human activities. Nevertheless, since it is not constrained by computational details, the study of situational awareness provides a unique opportunity to approach complex tasks of operation from an analytical perspective. In other words, with SA, we get to see how humans observe, recognize and react to complex systems on which they exert some control. Reconciling this perspective on complexity with complex systems research, it might be possible to further our understanding of complex phenomena if we can probe the anatomical mechanisms by which we, as humans, do it naturally. At this unique intersection of two disciplines, a hybrid approach is needed. So in this work, we propose just such an approach. In particular, this research proposes a computational approach to the situational awareness (SA) of complex systems. Here we propose to implement certain aspects of situational awareness via a biologically-inspired machine-learning technique called Hierarchical Temporal Memory (HTM). In doing so, we will use either simulated or actual data to create and to test computational implementations of situational awareness. This will be tested in two example contexts, one being more complex than the other. The ultimate goal of this research is to demonstrate a possible approach to analyzing and understanding complex systems. By using HTM and carefully developing techniques to analyze the SA formed from data, it is believed that this goal can be obtained.

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