2,560 research outputs found
Application of advanced technologies to small, short-haul aircraft
The results of a preliminary design study which investigates the use of selected advanced technologies to achieve low cost design for small (50-passenger), short haul (50 to 1000 mile) transports are reported. The largest single item in the cost of manufacturing an airplane of this type is labor. A careful examination of advanced technology to airframe structure was performed since one of the most labor-intensive parts of the airplane is structures. Also, preliminary investigation of advanced aerodynamics flight controls, ride control and gust load alleviation systems, aircraft systems and turbo-prop propulsion systems was performed. The most beneficial advanced technology examined was bonded aluminum primary structure. The use of this structure in large wing panels and body sections resulted in a greatly reduced number of parts and fasteners and therefore, labor hours. The resultant cost of assembled airplane structure was reduced by 40% and the total airplane manufacturing cost by 16% - a major cost reduction. With further development, test verification and optimization appreciable weight saving is also achievable. Other advanced technology items which showed significant gains are as follows: (1) advanced turboprop-reduced block fuel by 15.30% depending on range; (2) configuration revisions (vee-tail)-empennage cost reduction of 25%; (3) leading-edge flap addition-weight reduction of 2500 pounds
Phase transitions in ethylene oxide – methyl methacrylate block copolymers
This thesis describes the methods of anionic polymerisation and characterisation of poly(ethylene oxide) - poly(methyl methacrylate) block copolymers. Several experimental techniques have been used to study the phase transitions in these block copolymers as well as the corresponding binary blends. These techniques have included the following: differential scanning calorimetry, optical microscopy, small angle light scattering, small angle and wide angle x-ray scattering. A major part of this work involved the design, construction and operation of the small angle light scattering technique. The isothermal crystallisation kinetics of both the block copolymers and blends with high percentages of ethylene oxide component were investigated. The phase behaviour of the block copolymers and the blends was also studied. This involved analysing melting point depression and glass d-ansition data as well as investigating the structural morphology of the polymer systems. The phase behaviour of the block copolymers and die blends containing intermediate component compositions was observed at temperatures below the melting point temperature of PEO. For two block copolymer systems containing 50% and 55% by weight ethylene oxide, the chemical joint within die block inhibited crystallisation directly from the melt. These block copolymers microphase separated at low temperatures forming microdomains rich in PEO. Upon heating, the PEO microdomains crystallised A phase diagram incorporating this behaviour as well as the phase behaviour of the blends is presented. The structure from the micron level and below of the phase separated and crystalline regions has also been deduced. A block copolymer containing 76% ethylene oxide by weight crystallised directly from the melt. The isothermal crystallisation mechanism was very similar to that of the corresponding blend, however, the rate of crystallisation was appreciably slower and the melting point reduced. Comparison of analysed data from several techniques has allowed the contributions to the isothermal crystallisation mechanism to be distinguishe
Quantum linear network coding as one-way quantum computation
Network coding is a technique to maximize communication rates within a
network, in communication protocols for simultaneous multi-party transmission
of information. Linear network codes are examples of such protocols in which
the local computations performed at the nodes in the network are limited to
linear transformations of their input data (represented as elements of a ring,
such as the integers modulo 2). The quantum linear network coding protocols of
Kobayashi et al [arXiv:0908.1457 and arXiv:1012.4583] coherently simulate
classical linear network codes, using supplemental classical communication. We
demonstrate that these protocols correspond in a natural way to
measurement-based quantum computations with graph states over over qudits
[arXiv:quant-ph/0301052, arXiv:quant-ph/0603226, and arXiv:0704.1263] having a
structure directly related to the network.Comment: 17 pages, 6 figures. Updated to correct an incorrect (albeit
hilarious) reference in the arXiv version of the abstrac
Interactive Channel Capacity Revisited
We provide the first capacity approaching coding schemes that robustly
simulate any interactive protocol over an adversarial channel that corrupts any
fraction of the transmitted symbols. Our coding schemes achieve a
communication rate of over any
adversarial channel. This can be improved to for
random, oblivious, and computationally bounded channels, or if parties have
shared randomness unknown to the channel.
Surprisingly, these rates exceed the interactive channel capacity bound
which [Kol and Raz; STOC'13] recently proved for random errors. We conjecture
and to be the optimal rates for their respective settings
and therefore to capture the interactive channel capacity for random and
adversarial errors.
In addition to being very communication efficient, our randomized coding
schemes have multiple other advantages. They are computationally efficient,
extremely natural, and significantly simpler than prior (non-capacity
approaching) schemes. In particular, our protocols do not employ any coding but
allow the original protocol to be performed as-is, interspersed only by short
exchanges of hash values. When hash values do not match, the parties backtrack.
Our approach is, as we feel, by far the simplest and most natural explanation
for why and how robust interactive communication in a noisy environment is
possible
Experimental observation of chimera and cluster states in a minimal globally coupled network
A "chimera state" is a dynamical pattern that occurs in a network of coupled
identical oscillators when the symmetry of the oscillator population is broken
into synchronous and asynchronous parts. We report the experimental observation
of chimera and cluster states in a network of four globally coupled chaotic
opto-electronic oscillators. This is the minimal network that can support
chimera states, and our study provides new insight into the fundamental
mechanisms underlying their formation. We use a unified approach to determine
the stability of all the observed partially synchronous patterns, highlighting
the close relationship between chimera and cluster states as belonging to the
broader phenomenon of partial synchronization. Our approach is general in terms
of network size and connectivity. We also find that chimera states often appear
in regions of multistability between global, cluster, and desynchronized
states
PolyFS Visualizer
One of the most important operating system topics, file systems, control how we store and access data and form a key point in a computer scientists understanding of the underlying mechanisms of a computer. However, file systems, with their abstract concepts and lack of concrete learning aids, is a confusing subjects for students. Historically at Cal Poly, the CPE 453 Introduction to Operating Systems has been on of the most failed classes in the computing majors, leading to the need for better teaching and learning tools. Tools allowing students to gain concrete examples of abstract concepts could be used to better prepare students for industry.
The PolyFS Visualizer is a block level file system visualization service built for the PolyFS and TinyFS file systems design specifications currently used by some of professors teaching CPE 453. The service allows students to easily view the blocks of their file system and see metadata, the blocks binary content and the interlinked structure. Students can either compile their file system code with a provided block emulation library to build their disk on a remote server and make use of a visualization website or place the file mounted as their file system directly into the visualization service to view it locally. This allows students to easily view, debug and explore their implementation of a file system to understand how different design decisions affect its operation.
The implementation includes three main components: a disk emulation library in C for compilation with students code, a node JS back-end to handle students file systems and block operations and a read only visualization service. We have conducted two surveys of students in order to determine the usefulness of the PolyFS Visualizer. Students responded that the use of the PolyFS visualizer helps with the PolyFS file system design project and has several ideas for future features and expansions
The *subjectivity* of subjective experience - A representationalist analysis of the first-person perspective
This is a brief and accessible English summary of the "Self-model Theory of Subjectivity" (SMT), which is only available as German book in this archive. It introduces two new theoretical entities, the "phenomenal self-model" (PSM) and the "phenomenal model of the intentionality-relation" PMIR. A representationalist analysis of the phenomenal first-person persepctive is offered.
This is a revised version, including two pictures
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