[pt] Esta pesquisa buscou realizar a análise do processo de formação de alianças estratégicas internacionais no mercado de manutenção aeronáutica brasileiro através do estudo de uma aliança formada entre as empresas Comaf Indústria Aeronáutica (Brasil) e Limco Airepair (EUA). A metodologia de pesquisa adotada foi a do estudo de caso com enfoque qualitativo, que permitiu um estudo aprofundado de todo o processo de formação da aliança e de suas características. Como estrutura de estudo, foi adotado o modelo de análise de formação de alianças estratégicas desenvolvido por Bruno e Vasconcelos (1996) e, com base nele, foram analisados os dados pertinentes ao estudo em questão divididos em cinco etapas: definição estratégica, escolha da parceria, negociação/definição do projeto, implementação/execução e encerramento. O estudo apontou que as empresas envolvidas, mesmo que involuntariamente, seguiram bem de perto as etapas elaboradas pelo modelo utilizado e que, consequentemente, obtiveram êxito no processo de formação da parceria e nos momentos iniciais de execução da mesma. Tanto a empresa brasileira quanto a empresa americana foram capazes de atingir seus objetivos estratégicos iniciais através da formação da aliança estratégica. Por último, são feitas conclusões sobre o estudo realizado e apresentadas proposições que podem ser adotadas tanto pelas empresas em estudo, quanto por outras, para que o processo de formação de alianças estratégicas se torne mais eficiente e com maior chance de sucesso. / [en] This research attempted to analyse the formation process of international strategic alliances in the Brazilian aeronautical maintenance market through the study of an alliance formed between the companies Comaf Indústria Aeronáutica (Brazil) and Limco Airepair (USA). The chosen research methodology was that of the case study with a qualitative emphasis, that allowed for an in depth study of the entire alliance formation process as well as of its characteristics. As a structure for the study, the model for analysis of strategic alliance formation processes, developed by Bruno and Vasconcelos (1996) was used and, based on it, all data was analysed divided into five categories: strategic definition, choice of partner, project negotiation/definition, implementation/execution and closing. The study showed that the involved companies, even if involuntarily, followed the model s phases very closely and, consequently, had success in the alliance s formation process and initial periods of execution. Both the Brazilian and the American companies where able to reach their initial strategic objectives through the formation of the strategic alliance. Finally, conclusions are presented about the conducted research and propositions are made that can be adopted both by the studied companies, but also by others, so that the strategic alliance formation process can become more efficient and with a greater chance of success.

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In aircraft with jet propulsion engine intakes at supersonic speed, strong pressure waves referred to as shockwaves occur, which may interact with any present boundary layers along the intake surface. The adverse pressure gradients associated with Shock Wave-Boundary Layer Interaction (SWBLI) may cause boundary layer flow separation, which can result in disturbances of the flow that can be harmful to the device or decrease engine performance. A common way in dealing with the adverse effects of SWBLI is through removal of low-momentum flow in the boundary layer, a process referred to as boundary layer bleed. In the process of bleed, the boundary layer is subjected to a pressure difference promoting flow out of the system, through a porous surface, and into a plenum. The porous surfaces used in the mass flow removal process contain orifices in small scales. Thus, in Computational Fluid Dynamics (CFD), creating a mesh resolving both the orifice scales and the bulk flow is a cumbersome task, and the computational cost becomes substantially increased. To this end, several boundary conditions which effectively model the large-scale effects of bleed have been developed. The aim of this study is to implement the Boundary Condition (BC) developed by John W. Slater into M-EDGE, the in-house compressible CFD-solver of SAAB Aeronautics. The bleed boundary condition model is based on a dimensionless surface sonic flow coefficient, which is derived from empirical wind-tunnel measurements of the bleed mass flow. In previous work, the Slater bleed BC has been shown to correlate well with wind-tunnel data. Furthermore, a simple transpiration law formulated by Reynald Bur was implemented in order get familiarized with the M-EDGE Fortran source code. However, this model is expected to yield unsatisfactory results, as reported in previous work in the field. The implemented Slater BC is tested on two different two-dimensional flow cases; flow over a flat plate without SWBLI, and flow including a shock wave generator creating SWBLI. In the flat plate case, simulations were run at Mach numbers 1.27, 1.58, 1.98 and 2.46 over a 6.85cm plate of 19% porosity. In the SWBLI-case, only flow at Mach 2.46 was considered, with a 9.53cm plate of 21% porosity. The Reynolds number range used throughout was 1.39−1.76·10^7/m. Simulations were run at different bleed rates over a structured grid using steady state RANS with the Spalart-Allmaras one-equation turbulence model. The boundary condition performance was assessed by its ability to recreate the sonic flow coefficients on which it is based. Further, the shape of downstream pitot pressure profiles are compared with experimental data. Results from the studies indicate that the implementation manages to recreate the data for the sonic flow coefficient with small error margins. The implementation can be used to simulate porous plates of different dimensions and porosities, even though the bleed model is based on empirical mass flow measurements of a 6.85cmplate of 19% porosity. The implementation is able to predict global bleed effects in the flow field, as indicated by comparisons of pitot pressure profiles at various downstream reference planes, despite differences in reference boundary layer intake profiles. Further, the overall flow field was compared visually with other simulation-studies, indicating that the global Mach distributions of the geometries were in accordance with the reference data. However, pitot profiles should be further studied with better matched intake boundary layer profiles. The main limitation of the boundary condition is that it relies on the wind-tunnel data of the surface sonic flow coefficients for specific bleed plate configurations. Furthermore, the implementation has only been verified to work within specific Mach number range of the underlying empirical measurements. In future work, the generality of the model could be increased by extending the data to other configurations and Mach numbers by conducting new experiments or using other published empirical data.

An investigation was conducted into the feasibility of using an unconventional flight technique, asymmetric flight, to improve overall efficiency of solar aircraft. In this study, asymmetric flight is defined as steady level flight in a non-wings-level state in- tended to improve solar incidence angle. By manipulating aircraft orientation through roll angle, solar energy collection is improved but aerodynamic efficiency is worsened due to the introduction of additional trim drag. A point performance model was devel- oped to investigate the trade-off between improvement in solar energy collection and additional drag associated with asymmetric flight. A mission model with a focus on aircraft orbits was then developed via integration of the point performance model over a set of discrete points. It is shown that there is a non-zero bank angle where optimal net power is achieved for a given aircraft orientation, flight condition, and sun position. The study also shows that there is improvement in overall efficiency over conventional flight for various orbit shapes and winds aloft. This indicates that there is potential value in not only flight path planning, but also in orientation planning for solar aircraft.

Aeronautical telemetry systems have historically been implemented with constant envelope modulations like CPM. Shifts in system constraints including reduced available bandwidth and increased throughput demands have caused many in the field to reevaluate traditional methods and design practices. This work examines the costs and benefits of using APSK for aeronautical telemetry instead of CPM. Variable rate turbo codes are used to improve the power efficiency of 16- and 32-APSK. Spectral regrowth in nonlinear power amplifiers when driven by non-constant envelope modulation is also considered. Simulation results show the improved spectral efficiency of this modulation scheme over those currently defined in telemetry standards. Additionally, the impact of transitioning from continuous transmission to burst-mode is considered. Synchronization loops are ineffective in burst-mode communication. Data-aided feed forward algorithms can be used to estimate offsets in carrier phase, frequency, and symbol timing between the transmitter and the receiver. If a data-aided algorithm is used, a portion of the transmitted signal is devoted to a known sequence of pilot symbols. Optimum pilot sequences for the three synchronization parameters are obtained analytically and numerically for different system constraints. The alternating sequence is shown to be optimal given a peak power constraint. Alternatively, synchronization can be accomplished using blind algorithms that do not rely on a priori knowledge of a pilot sequence. If blind algorithms are used, the observation interval can be longer than for data-aided algorithms. There are combinations of pilot sequence length and packet length where data-aided algorithms perform better than blind algorithms and vice versa. The conclusion is that a sequential arrangement of blind algorithms operating over an entire burst performs better than a CRB-achieving data-aided algorithm operating over a short pilot sequence.

The conceptual design phase of an aerospace system development program is typically characterized by short duration and relatively limited resources, yet design decisions are made that have critical implications on program risk. To address the more aggressive requirements, one of these decisions is the selection of advanced technologies. System developers need to assess advanced technologies early on, but are faced with uncertainties surrounding the potential net benefits. The concept introduced in this study is uncertainty characterization as a way to better understand the associated risk. A framework was developed to guide the interaction between the technology developer and the system developer. The objective is to gain a more comprehensive landscape of the technology options by explicitly considering the effects of uncertainty in the decision making process. This can ultimately facilitate prioritization and resource management during conceptual design. An example case of advanced wing technology was applied to the design of a high-altitude long-endurance unmanned aerial vehicle to demonstrate the implementation of the framework.

Using a new implementation of a NASA flight simulation of the Quiet Short-Haul Research Aircraft, autopilots were designed to be capable of flying both straight in (ILS) approaches, and circling (SNI) approaches. A standard glideslope coupler was sufficient for most conditions, but a standard Proportional-Integral-Derivative (PID) based localizer tracker was not sufficient for maintaining a lateral track on the SNI course. To track the SNI course, a feed-forward system, using GPS steering provided much better results. NASA and the FAA embrace the concept of a Simultaneous, Non-Interfering (SNI) approach as a way to increase airport throughput while reducing the noise footprints of aircraft on approach. The NASA concept for the SNI approach for Short Takeoff and Landing (STOL) aircraft involves a straight in segment flown above the flight path of a normal approach, followed by a spiraling descent to the runway. As this is a procedure that would be utilized by regional airliners, it is assumed that it would be conducted under Instrument Flight Rules (IFR). GPS or INS guidance would be required to fly this approach, and it is likely that it would be necessary to fly the approach with a coupled autopilot: a stabilized, curving, instrument approach to decision altitude would be exceedingly difficult to fly. The autopilots in many current commuter and general aviation aircraft, however, were designed before the event of GPS, and do not have provisions for tracking curved paths. This study identifies problem areas in implementing the SNI circling approach on aircraft and avionics as they stand today and also gives examples of what can be done for the SNI approach to be successful.

Peanut digging timing is difficult to predict due to indeterminate growth and peanut pods maturing underground, resulting in the need to research methods that provide consistent measurements, while reducing time and effort for farmers and researchers. Experiments were conducted to evaluate the accuracy of the Maturity Index 1 and Maturity Index 2 in predicting peanut grade, the accuracy of the North Carolina 2 degree day method in predicting peanut yield, and remote sensing vegetative indices sensitivity equivalence (SEq) to peanut Maturity Index 2 and harvest grade (TSMK) for cultivars IPG-914 and Georgia-06G in Mississippi. Maturity Index 1 and Maturity Index 2 were found to be inaccurate predictions of peanut grade in Mississippi, suggesting a need to examine the contributions of individual color classes in new genotypes to predict grade and yield. The North Carolina 2 degree day method was found to have a moderate to strong relationship with yield, indicating its potential usefulness in determining digging timing. Results also showed red edge indices were more sensitive to changes in pod maturity and grade. Peanut genotype selection is critical for maximizing peanut grade and yield on farm. Experiments were conducted to evaluate 32 genotypes for maturity, grade, and yield. Several early maturing genotypes showed promise for improving yield and grade without reducing quality, particularly 'UF11x23-3-6-1-1', '16-1-2147', '16-1-2142', '14x029-1-5-1-1', and '14x022-1-2-1-2'. The results suggest earlier maturing genotypes may be a solution to the late-season harvest risk of crop loss due to poor digging conditions, rain, and frost, while maintaining similar pod grades and yield to the current market-leading cultivars. The findings of this study contribute to the ongoing effort to optimize digging timing and improve peanut yields in Mississippi, where peanut farmers face the dual challenges of climatic variability and genotype selection. Future research is needed to examine the adaptability of genotypes on differing soil types, management, and climates throughout Mississippi. Overall, this study highlights the need for more effective and accurate methods for determining digging timing in peanut crops, which is crucial for their grade, and yield.

Yes / This paper presents the architectural design, software implementation, the validation and flight trial results of an aeronautical communications system developed within the Seamless Aeronautical Networking through integration of Data links Radios and Antennas (SANDRA) project funded by the European 7th Framework Aeronautics and Transport Programme. Based on Software Defined Radio (SDR) techniques, an Integrated Modular Radio (IMR) platform was developed to accommodate several radio technologies. This can drastically reduce the size, weight and cost in avionics with respect to current radio systems implemented as standalone equipment. In addition, the modular approach ensures the possibility to dynamically reconfigure each radio element to operate on a specific type of radio link. A radio resource management (RRM) framework is developed in the IMR consisting of a communication manager for the resource allocation and management of the different radio links and a radio adaptation manager to ensure protocol convergence through IP. The IMR has been validated though flight trials held at Oberpfaffenhofen, Germany in June 2013. The results presented in the paper validate the flexibility and scalability of the IMR platform and demonstrate seamless service coverage across different airspace domains through interworking between the IMR and other components of the SANDRA network. / European Commission

Thesis (M.Tech.) - Central University of Technology, Free State, 2007 / The latest technological trend worldwide, is automation. Reducing human labour and introducing robots to do the work is a pure business decision. The reason for automating a plant can be some, or all, of the following: Improve productivity Reduce labour and equipment costs Reduce product damage System reliability can be monitored Improves plant safety When the automation process is started, Automatic Guided Vehicles (AGVs) will be one of the first commodities that can be used. The reason for this is that they are so versatile. They can be programmed to follow specific paths when moving material from one point to another and the biggest advantage of all is that they can operate for twenty four hours a day. Automatic Guided Vehicles are developed for many different applications and therefore many different types of AGVs are available. All AGVs are equipped with sensors so that they are able to “see” what is happening around them. Since the AGV must be able to function without any human help or control, it must be able to navigate through the work environment. In this study a remote control car was converted to an AGV and thorough research was done on the different types of sensors that can be used to make the AGV more intelligent when it comes to navigating in an unknown environment.