105 research outputs found
Air Force Institute of Technology Research Report 2007
This report summarizes the research activities of the Air Force Institute of Technology’s Graduate School of Engineering and Management. It describes research interests and faculty expertise; lists student theses/dissertations; identifies research sponsors and contributions; and outlines the procedures for contacting the school. Included in the report are: faculty publications, conference presentations, consultations, and funded research projects. Research was conducted in the areas of Aeronautical and Astronautical Engineering, Electrical Engineering and Electro-Optics, Computer Engineering and Computer Science, Systems and Engineering Management, Operational Sciences, Mathematics, Statistics and Engineering Physics
Bio-inspired optimization algorithms for smart antennas
This thesis studies the effectiveness of bio-inspired optimization algorithms in
controlling adaptive antenna arrays. Smart antennas are able to automatically
extract the desired signal from interferer signals and external noise. The angular
pattern depends on the number of antenna elements, their geometrical arrangement,
and their relative amplitude and phases. In the present work different
antenna geometries are tested and compared when their array weights are optimized
by different techniques. First, the Genetic Algorithm and Particle Swarm
Optimization algorithms are used to find the best set of phases between antenna
elements to obtain a desired antenna pattern. This pattern must meet several
restraints, for example: Maximizing the power of the main lobe at a desired direction
while keeping nulls towards interferers. A series of experiments show that
the PSO achieves better and more consistent radiation patterns than the GA in
terms of the total area of the antenna pattern. A second set of experiments use
the Signal-to-Interference-plus-Noise-Ratio as the fitness function of optimization
algorithms to find the array weights that configure a rectangular array. The results
suggest an advantage in performance by reducing the number of iterations
taken by the PSO, thus lowering the computational cost. During the development
of this thesis, it was found that the initial states and particular parameters of
the optimization algorithms affected their overall outcome. The third part of this
work deals with the meta-optimization of these parameters to achieve the best
results independently from particular initial parameters. Four algorithms were
studied: Genetic Algorithm, Particle Swarm Optimization, Simulated Annealing
and Hill Climb. It was found that the meta-optimization algorithms Local Unimodal
Sampling and Pattern Search performed better to set the initial parameters
and obtain the best performance of the bio-inspired methods studied
Communication centric platforms for future high data intensive applications
The notion of platform based design is considered as a viable solution to boost the
design productivity by favouring reuse design methodology. With the scaling down of
device feature size and scaling up of design complexity, throughput limitations, signal
integrity and signal latency are becoming a bottleneck in future communication centric
System-on-Chip (SoC) design. This has given birth to communication centric platform
based designs.
Development of heterogeneous multi-core architectures has caused the on-chip
communication medium tailored for a specific application domain to deal with multidomain
traffic patterns. This makes the current application specific communication centric
platforms unsuitable for future SoC architectures.
The work presented in this thesis, endeavours to explore the current
communication media to establish the expectations from future on-chip interconnects. A
novel communication centric platform based design flow is proposed, which consists of
four communication centric platforms that are based on shared global bus, hierarchical
bus, crossbars and a novel hybrid communication medium. Developed with a smart
platform controller, the platforms support Open Core Protocol (OCP) socket standard,
allowing cores to integrate in a plug and play fashion without the need to reprogram the
pre-verified platforms. This drastically reduces the design time of SoC architectures. Each
communication centric platform has different throughput, area and power characteristics,
thus, depending on the design constraints, processing cores can be integrated to the most
appropriate communication platform to realise the desired SoC architecture.
A novel hybrid communication medium is also developed in this thesis, which
combines the advantages of two different types of communication media in a single SoC
architecture. The hybrid communication medium consists of crossbar matrix and shared
bus medium . Simulation results and implementation of WiMAX receiver as a real-life
example shows a 65% increase in data throughput than shared bus based communication
medium, 13% decrease in area and 11% decrease in power than crossbar based
communication medium.
In order to automate the generation of SoC architectures with optimised
communication architectures, a tool called SOCCAD (SoC Communication architecture
development) is developed. Components needed for the realisation of the given application
can be selected from the tool’s in-built library. Offering an optimised communication
centric placement, the tool generates the complete SystemC code for the system with
different interconnect architectures, along with its power and area characteristics. The
generated SystemC code can be used for quick simulation and coupled with efficient test
benches can be used for quick verification.
Network-on-Chip (NoC) is considered as a solution to the communication
bottleneck in future SoC architectures with data throughput requirements of over 10GB/s.
It aims to provide low power, efficient link utilisation, reduced data contention and
reduced area on silicon. Current on-chip networks, developed with fixed architectural
parameters, do not utilise the available resources efficiently. To increase this efficiency, a
novel dynamically reconfigurable NoC (drNoC) is developed in this thesis. The proposed
drNoC reconfigures itself in terms of switching, routing and packet size with the changing
communication requirements of the system at run time, thus utilising the maximum
available channel bandwidth. In order to increase the applicability of drNoC, the network
interface is designed to support OCP socket standard. This makes drNoC a highly reuseable
communication framework, qualifying it as a communication centric platform for
high data intensive SoC architectures. Simulation results show a 32% increase in data
throughput and 22-35% decrease in network delay when compared with a traditional NoC
with fixed parameters
Beamed-Energy Propulsion (BEP) Study
The scope of this study was to (1) review and analyze the state-of-art in beamed-energy propulsion (BEP) by identifying potential game-changing applications, (2) formulate a roadmap of technology development, and (3) identify key near-term technology demonstrations to rapidly advance elements of BEP technology to Technology Readiness Level (TRL) 6. The two major areas of interest were launching payloads and space propulsion. More generally, the study was requested and structured to address basic mission feasibility. The attraction of beamed-energy propulsion (BEP) is the potential for high specific impulse while removing the power-generation mass. The rapid advancements in high-energy beamed-power systems and optics over the past 20 years warranted a fresh look at the technology. For launching payloads, the study concluded that using BEP to propel vehicles into space is technically feasible if a commitment to develop new technologies and large investments can be made over long periods of time. From a commercial competitive standpoint, if an advantage of beamed energy for Earth-to-orbit (ETO) is to be found, it will rest with smaller, frequently launched payloads. For space propulsion, the study concluded that using beamed energy to propel vehicles from low Earth orbit to geosynchronous Earth orbit (LEO-GEO) and into deep space is definitely feasible and showed distinct advantages and greater potential over current propulsion technologies. However, this conclusion also assumes that upfront infrastructure investments and commitments to critical technologies will be made over long periods of time. The chief issue, similar to that for payloads, is high infrastructure costs
Air Force Institute of Technology Research Report 2017
This Research Report presents the FY18 research statistics and contributions of the Graduate School of Engineering and Management (EN) at AFIT. AFIT research interests and faculty expertise cover a broad spectrum of technical areas related to USAF needs, as reflected by the range of topics addressed in the faculty and student publications listed in this report. In most cases, the research work reported herein is directly sponsored by one or more USAF or DOD agencies. AFIT welcomes the opportunity to conduct research on additional topics of interest to the USAF, DOD, and other federal organizations when adequate manpower and financial resources are available and/or provided by a sponsor. In addition, AFIT provides research collaboration and technology transfer benefits to the public through Cooperative Research and Development Agreements (CRADAs)
Overlay virtualized wireless sensor networks for application in industrial internet of things : a review
Abstract: In recent times, Wireless Sensor Networks (WSNs) are broadly applied in the Industrial Internet of Things (IIoT) in order to enhance the productivity and efficiency of existing and prospective manufacturing industries. In particular, an area of interest that concerns the use of WSNs in IIoT is the concept of sensor network virtualization and overlay networks. Both network virtualization and overlay networks are considered contemporary because they provide the capacity to create services and applications at the edge of existing virtual networks without changing the underlying infrastructure. This capability makes both network virtualization and overlay network services highly beneficial, particularly for the dynamic needs of IIoT based applications such as in smart industry applications, smart city, and smart home applications. Consequently, the study of both WSN virtualization and overlay networks has become highly patronized in the literature, leading to the growth and maturity of the research area. In line with this growth, this paper provides a review of the development made thus far concerning virtualized sensor networks, with emphasis on the application of overlay networks in IIoT. Principally, the process of virtualization in WSN is discussed along with its importance in IIoT applications. Different challenges in WSN are also presented along with possible solutions given by the use of virtualized WSNs. Further details are also presented concerning the use of overlay networks as the next step to supporting virtualization in shared sensor networks. Our discussion closes with an exposition of the existing challenges in the use of virtualized WSN for IIoT applications. In general, because overlay networks will be contributory to the future development and advancement of smart industrial and smart city applications, this review may be considered by researchers as a reference point for those particularly interested in the study of this growing field
Six Decades of Flight Research: An Annotated Bibliography of Technical Publications of NASA Dryden Flight Research Center, 1946-2006
Titles, authors, report numbers, and abstracts are given for nearly 2900 unclassified and unrestricted technical reports and papers published from September 1946 to December 2006 by the NASA Dryden Flight Research Center and its predecessor organizations. These technical reports and papers describe and give the results of 60 years of flight research performed by the NACA and NASA, from the X-1 and other early X-airplanes, to the X-15, Space Shuttle, X-29 Forward Swept Wing, X-31, and X-43 aircraft. Some of the other research airplanes tested were the D-558, phase 1 and 2; M-2, HL-10 and X-24 lifting bodies; Digital Fly-By-Wire and Supercritical Wing F-8; XB-70; YF-12; AFTI F-111 TACT and MAW; F-15 HiDEC; F-18 High Alpha Research Vehicle, F-18 Systems Research Aircraft and the NASA Landing Systems Research aircraft. The citations of reports and papers are listed in chronological order, with author and aircraft indices. In addition, in the appendices, citations of 270 contractor reports, more than 200 UCLA Flight System Research Center reports, nearly 200 Tech Briefs, 30 Dryden Historical Publications, and over 30 videotapes are included
Aeronautics and Space Report of the President: Fiscal Year 2009 Activities
In fiscal year 2009 (FY 09), the Exploration Systems Mission Directorate's (ESMD) Advanced Capabilities Division (ACD) provided critical research and technology products that reduced operational and technical risks for the flight systems being developed by the Constellation Program.1 These products addressed high-priority technology requirements for lunar exploration; risk mitigation related to astronaut health and performance; basic research in life and physical sciences using the International Space Station (ISS), free-flying spacecraft, and ground-based laboratories; and lunar robotic missions to gather data relevant to future human lunar missions
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