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<p>The wind power industry is maturing and the amount of electricity produced by wind turbines in the world is rapidly increasing every year. Service and maintenance of wind turbines has proven to be difficult and expensive, especially offshore. A well coordinated support organisation and optimized maintenance strategies are required to effectively reduce the costs associated with WT support, where cost-efficient supply and storage of spare parts are important. The aim of this thesis is to model spare part logistics for wind turbines to analyse different strategies and compare the profitability. Optimal stock levels and reorder sizes have been calculated with the software tool OPUS10. Wind turbine and spare part data have been provided by Vattenfall Vindkraft AB and field studies were made to the wind farms Lillgrund and Horns Rev to gather information.</p><p>Our analyses show that different spare part strategies only affect a minor part of the total support costs generated for a wind farm. Still there are many improvements possible and money to be saved if using an optimal spare part strategy instead of one based on personal experiences and intuition. For a large wind power system, including a number of wind farms with the same wind turbine types, we also show convincing results that pooling of spare parts are a much more cost-efficient spare part strategy compared to local storage and handling only. Using a central depot for spare part reordering and storage of critical spare parts, such as gearboxes, generators and blades, are more profitable</p>

Thesis (Ph.D.)--School of Mechanical Engineering, Georgia Institute of Technology, 2005. / Singhose, William, Committee Chair ; Banerjee, Arun, Committee Member ; Chen, Ye-Hwa, Committee Member ; Ebert-Uphoff, Imme, Committee Member ; Olds, John, Committee Member. Includes bibliographical references.

Command generation is a process by which input commands are constructed or modified such that the system's response adheres to a set of desired performance specifications. Previously, a variety of command generation techniques such as input shaping have been used to reduce residual vibration, limit transient deflection, conserve fuel or adhere to numerous other performance specifications or performance measures. This dissertation addresses key issues regarding the application of command generation techniques to tethered satellite systems. The three primary objectives of this research are as follows: 1) create analytically commands that will limit the deflection of flexible systems 2) combine command generation and feedback control to reduce the retrieval time of tethered satellites, and 3) develop command generation techniques for spinning tether systems. More specifically, the proposed research addresses six specific aspects of command generation for tethered satellites systems: 1) create command shapers that can limit the trajectory tracking for a mass under PD control to a pre-specified limit in real time 2) create commands analytically that can limit the transient deflection of a model with one rigid-body and one flexible mode during rest-to-rest maneuvers 3) command generation for a 2-D model of earth-pointing tethered satellites without tether flexibility, 4) command generation for a 2-D model of earth-pointing tethered satellites to reduce tether retrieval time and reduce swing angle, 5) command generation for a 3-D model of earth-pointing tethered satellites without tether flexibility, and 6) command generation for improved spin-up of spinning tethered satellite systems. The proposed research is anticipated to advance the state-of-the-art in the field of command generation for tethered satellite systems and will potentially yield improvements in a number of practical satellite and tether applications.

Ett allt vanligare fenomen är att civila samhällsaktörer använder drönare i arbetet. En av dem är Polismyndigheten vars förmåga benämns UAS, en akronym för Unmanned Aircraft System. UAS används bland annat för ledning av operativa insatser. Syftet med studien var att undersöka hur användningen av UAS påverkar polisens ledning av insatser. Den polisiära UAS-användningen har för avsikt att höja polisens ledningsförmåga. Enligt tidigare forskning kan detta normativa påstående tolkas som ett designförslag. Med denna utgångspunkt undersökte studien empiriskt hur UAS-användningen påverkar polisens möjligheter att nå önskade effekter av insatser. Undersökningen genomfördes med stöd av Brehmers (2013) designlogik bestående av fem analysnivåer. Designlogiken applicerades på primärt på ledningssystemet i relation till insatssystemet.  Empirin utgjordes av sju individuella och semistrukturerade intervjuer. Intervjuerna analyserades med deduktiv tematisk analys. Resultaten visar att det finns effekthöjande faktorer, effekthämmande faktorer och effektsänkande (risk)faktorer gällande polisens UASanvändning vid insatsledning. Studiens slutsats är att det är hur relationen mellan dessa faktorer ser ut vid varje unik insats som påverkar vilken betydelse UAS-användningen får för ledningsförmågan, och därmed också vilka effekter som kan uppnås med insatsen som helhet. Det finns därmed en riktighet, men inte en garanti, i påståendet att UAS-användning genererar ökad ledningsförmåga vid ledning av operativa insatser. Att UAS-användningen höjer ledningsförmågan förutsätter att omständigheterna är gynnsamma/hanterbara och att de effektsänkande (risk)faktorerna kan undvikas/hanteras. / An increasingly common phenomenon is that civil society actors utilizes drones in work-related situations. Amongst them is the Swedish Police Authority, whose capability entitles UAS, an acronym for Unmanned Aircraft System. One way in which the Swedish police uses UAS is for command and control (C2) of operations. The purpose of the study was to investigate how the UAS-usage affects the management of C2 operations. Through UAS-usage, the Swedish police intends at increasing the police's C2 ability. According to previous research, this normative statement could be interpreted as a design proposal. Following this, the study investigated empirically how the UAS-usage affects the police's ability to achieve desired effects of C2 operations. To conduct the research, the study used Brehmer's (2013) design logic consisting of five levels of analysis. The design logic was applied primarily to the C2-system in relation to the mission respondent system.  The empirics consisted of seven semi-structured interviews, which all took place individually. The interviews were analyzed with deductive thematic analysis. Results are showing that UAS-usage in C2 operations has effect-enhancing factors, effect-inhibiting factors and effect-reducing (risk) factors. The study states that the relationship between these factors in each unique C2 operation affects how UAS-usage influences the C2 ability, and hence which effects the operation as a whole produces. There is thus an accuracy, but not a guarantee, in the claim that UAS-usage generates increased C2 ability. The achievement of increased C2 ability through UAS-usage is dependent on favorable/manageable circumstances and the fact that the effect-reducing (risk) factors can be avoided/managed.

Approved for public release; distribution is unlimited / The purpose of this thesis is to use wargaming and simulation to gain insight into the effective employment of a new Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR) system, the Adaptive Joint C4ISR Node (AJCN). The AJCN provides the supported commander with several capabilities, to include: range extension, waveform bridging, signal intelligence, electronic warfare, and information operations. Two methods are used to gain insight to the support generation of the concept of operations for the AJCN's employment. The first method is wargaming. The wargaming method utilized a class of NPS students and the JCATS combat simulation model. The wargaming generated insights concerning the AJCN's employment. The second method is the use of a constructive simulation model, POA 2. Insights gained from the two methods include: the need for commanders to differentiate the AJCN and its supporting platform; the need for effective information processing techniques; the importance of maintaining at least two-tiers of AJCN coverage to enhance situational awareness of the supported units. / Major, United States Army / Captain, United States Army

This thesis describes an Extensible Markup Language (XML) based analysis and comparison method that could be used to identity equivalent components of heterogeneous databases. In the Department of Defense there currently exist multiple databases required to support command and control of some portion of the battlefield force. Interoperability between forces will become crucial as the force structure continues to be reduced. This interoperability will be facilitated through the integration of these command and control databases into a singular joint database or by developing inter- communication schema to support inter-database communications. The first step in either of these alternatives is the identification of equivalent components among the multiple databases. This thesis describes how XML can be used to facilitate the process of analyzing and comparing multiple databases. Each step of the process is described in detail accompanied by explanations of the XML tools/resources required to execute the step and rationale of why the step is necessary. Detailed graphics and examples are employed to simplify and justify the step by step explanations. The JavaScript code developed as part of the research to execute the XML based analysis is included. This thesis concludes with discussions of the overall value of this XML based analysis and comparison process and of potential future work, that could be pursued to further exploit this XML analysis and comparison method. / Naval Postgraduate School author (civilian)

With the DoD acquisition of programs and projects becoming increasingly expensive, it is imperative that the method or measure for determining value for a particular project, real or conceptual, be identified and used enterprise-wide. The form of analysis known as the Knowledge Value Added (KVA) methodology, KVA will evaluate the Office Force Transformation Wolf-PAC / Stiletto concepts. This thesis will explore two distinctly different areas which demonstrate the KVA method's use and benefit: 1. The use of the KVA method to find improvements in a Command and Control (C2) process, and 2. To demonstrate the increase value that the Stiletto ship brings to littoral operations (i.e., Mine hunting). The resulting values will be compared in varying notional scenarios to assess potential improvements for knowledge processes. This method of analysis will demonstrate how a reengineered process, resulting from the KVA method, enables organizations to maximize knowledge creation and production capacity.

Control (C2) process. Situations often occur in which forward air controllers (FACs) from one service integrate into the structure of another service, yet still report to their own leadership. Many non-interoperable communications systems are used, further adding to the confusion. This thesis analyzes the effectiveness of current Joint Close Air Support doctrine in providing the guidelines necessary for the warfighter at all echelons to plan, prepare and execute integrated close air support missions seamlessly when operating in a joint environment. Themes which hamper the ability to efficiently employ command and control (C2) to provide close air support to the Ground Combat Commander are examined. Finally, Naval Surface Fire Support is studied to determine its place in the JCAS architecture and where, within that architecture, it should be implemented. The analysis of case studies involving situations in which JCAS was not used effectively revealed that, though there has been significant progress made in revising Joint CAS doctrine, weaknesses still exist. Joint doctrine must keep pace with emerging technology but for that doctrine to remain relevant, warfighters at all levels must know it, use it and provide feedback when it doesnâ t work so future iterations can mature and flex with the force. / US Naval Reserve (USNR) author.

Thesis (Ph. D.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Valdes Berzins, Luqi, William Kemple, Mikhail Auguston, Nabendu Chaki. Includes bibliographical references (p. 231-240). Also available online.