Dissertations / Theses on the topic 'Computer engineering, n.e.c'
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Yang, Xuejun. "Random testing of open source C compilers." Thesis, The University of Utah, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3704288.
Full textCompilers are indispensable tools to developers. We expect them to be correct. However, compiler correctness is very hard to be reasoned about. This can be partly explained by the daunting complexity of compilers.
In this dissertation, I will explain how we constructed a random program generator, Csmith, and used it to find hundreds of bugs in strong open source compilers such as the GNU Compiler Collection (GCC) and the LLVM Compiler Infrastructure (LLVM). The success of Csmith depends on its ability of being expressive and unambiguous at the same time. Csmith is composed of a code generator and a GTAV (Generation-Time Analysis and Validation) engine. They work interactively to produce expressive yet unambiguous random programs. The expressiveness of Csmith is attributed to the code generator, while the unambiguity is assured by GTAV. GTAV performs program analyses, such as points-to analysis and effect analysis, efficiently to avoid ambiguities caused by undefined behaviors or unspecified behaviors.
During our 4.25 years of testing, Csmith has found over 450 bugs in the GNU Compiler Collection (GCC) and the LLVM Compiler Infrastructure (LLVM). We analyzed the bugs by putting them into different categories, studying the root causes, finding their locations in compilers' source code, and evaluating their importance. We believe analysis results are useful to future random testers, as well as compiler writers/users.
Jiang, Yuandong. "Large Scale Distributed Semantic N-gram Language Model." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1316200173.
Full textTanga, Rajan M. "Computer aided software engineering tool for generating C code." Ohio : Ohio University, 1988. http://www.ohiolink.edu/etd/view.cgi?ohiou1182872759.
Full textHe, Jiliang. "Silyhydrazines : chemistry and pyrolytic conversion to Si-N-C ceramic materials." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=29044.
Full textMorse, Benjamin 1979. "A C/C++ front end for the Daikon dynamic invariant detection system." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/29653.
Full textIncludes bibliographical references (p. 73-75).
This thesis details the implementation and performance of a Daikon front end for the C and C++ languages. The Daikon dynamic invariant detection suite is a system designed to extract formal specifications from programs, in the form of information about their variables and their relationships to each other. The system consists of a front end and the analysis engine. The front end instruments the source code of a target program, inserting code that outputs the values of the program's variables when run. The user compiles and runs the instrumented program, generating a trace file that contains variable values. This data is then sent to Daikon proper, which performs analysis on it and reports invariants about the program variables. Daikon is a useful tool that can discover invariants that current static methods cannot find. While the invariant analysis tool is language independent, the front ends -- tools that instrument of the user code -- must be written for every language to be instrumented. There is a huge base of pre-existing code written in C/C++ for which invariants can be discovered. C and C++ are also widely deployed, comprise a large segment of software currently in development, and are therefore valuable candidates for analysis. The key difficulty in instrumenting a type-unsafe language like C is that the instrumented program has to determine what variables are valid, and to what extent; so that it does not output garbage values or cause a segmentation fault by dereferencing an invalid pointer.
by Benjamin Morse.
M.Eng.and S.B.
Guo, Philip Jia. "A scalable mixed-level approach to dynamic analysis of C and C++ programs." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36767.
Full textIncludes bibliographical references (p. 107-112).
This thesis addresses the difficult task of constructing robust and scalable dynamic program analysis tools for programs written in memory-unsafe languages such as C and C++, especially those that are interested in observing the contents of data structures at run time. In this thesis, I first introduce my novel mixed-level approach to dynamic analysis, which combines the advantages of both source- and binary-based approaches. Second, I present a tool framework that embodies the mixed-level approach. This framework provides memory safety guarantees, allows tools built upon it to access rich source- and binary-level information simultaneously at run time, and enables tools to scale to large, real-world C and C++ programs on the order of millions of lines of code. Third, I present two dynamic analysis tools built upon my framework - one for performing value profiling and the other for performing dynamic inference of abstract types - and describe how they far surpass previous analyses in terms of scalability, robustness, and applicability. Lastly, I present several case studies demonstrating how these tools aid both humans and automated tools in several program analysis tasks: improving human understanding of unfamiliar code, invariant detection, and data structure repair.
by Philip Jia Guo.
M.Eng.
Saha, Sagnik M. Eng Massachusetts Institute of Technology. "Adding Support for MC/DC instrumentation in the Green Hills C/C++ compiler." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/121681.
Full textThesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 49-50).
This thesis presents the design and implementation of Modified Condition / Decision Coverage (MC/DC) instrumentation in the Green Hills C/C++ compiler. When a specfic option is enabled, the compiler now identied each boolean expression and annotates the generated binary with special instructions. When a test suite is run, these extra instructions emit logging information. A separate program then uses that information to determine and display the degree of coverage achieved. Taken together, my tools allow a user to run any program and determine the extent of MC/DC coverage achieved by their tests.
by Sagnik Saha.
M. Eng.
M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
Liburd, Soyini (Soyini Denise) 1980. "An N-version electronic voting system." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28441.
Full textIncludes bibliographical references (p. 103-109).
The ballot battles of the 2000 US Presidential Election clearly indicate that existing voting technologies and processes are not sufficient to guarantee that every eligible voter is granted their right to vote and implicitly to have that vote counted, as per the fifteenth, nineteenth, twenty fourth and twenty sixth amendments to the US constitution [1-3]. Developing a voting system that is secure, correct, reliable and trustworthy is a significant challenge to current technology [3, 4]. The Secure Architecture for Voting Electronically (SAVE) demonstrates that N-version programming increases the reliability and security of its systems, and can be used to increase the trustworthiness of systems. Further, SAVE demonstrates how a viable practical approach to voting can be created using N-version programming. SAVE represents a significant contribution to voting technology research because of its design, and also because it demonstrates the benefits of N-version programming and introduces these benefits to the field of voting technology.
by Soyini D. Liburd.
M.Eng.
Rudd, Robert Andrew M. Eng Massachusetts Institute of Technology. "An improved scalable mixed-level approach to dynamic analysis of C and C++ programs." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61250.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (p. 85-86).
In this thesis, I address the challenges of developing tools which use a mixed-level approach to dynamic binary analysis. The mixed-level approach combines advantages of both source- based and binary-based approaches to dynamic analysis, but comes with the added challenge of dealing with the implementation details of a specific implementation of the target language. This thesis describes the implementation of three existing tools which use the mixed-level approach: Fjalar, a C/C++ dynamic analysis framework, Kvasir, A C/C++ value profiling tool, and Dyncomp, a tool for inferring the abstract types of a C or C++ program. Additionally, this thesis describes the steps I took in increasing the maintainability and portability of these tools. I investigated and documented platform specific dependencies; I documented the process of merging in upstream changes of Valgrind, the Dynamic Binary Instrumenter Fjalar is built on, to aid Fjalar in keeping in-sync with Valgrind bug-fixes; and I implemented a tool for debugging Dyncomp errors.
by Robert Andrew Rudd.
M.Eng.
Dagher, Issam J. "Gradient based fuzzy c-means algorithm." FIU Digital Commons, 1994. http://digitalcommons.fiu.edu/etd/2652.
Full textBrown, Jeremy Hanford 1972. "Feedback-directed specialization of C." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36604.
Full textIncludes bibliographical references (p. 115-116).
by Jeremy H. Brown.
M.Eng.
Kelly, Mark. "Laser diagnosis and computer modelling of C/H/O and C/H/N plasmas used in diamond chemical vapour deposition." Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.653079.
Full textGoyal, Poonam. "Comparative Study of C, Java, C# and Jython." UNF Digital Commons, 2014. http://digitalcommons.unf.edu/etd/535.
Full textPribyl, Patrick A. "Measured MHD equilibrium in Alcator C." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/14881.
Full textMICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaves 204-206.
by Patrick A. Pribyl.
Ph.D.
Ouerd, Messaouda. "An algorithm directed computer aided software engineering (CASE) environment for C." Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5964.
Full textMcAvoy, Camille Z. "Palladium-catalyzed C-N cross-coupling reactions toward the synthesis of drug-like molecules." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/73388.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (p. ).
The development of methodologies for C-N bond formation reactions is an important scientific challenge because of many academic and industrial applications. This work will focus particularly on palladium-catalyzed cross-couplings of amine-containing compounds with aryl halides. The scope of the BrettPhos precatalyst for the cross-coupling of ortho-substituted aryl iodides with amides is studied using substrates with a variety of functional groups. Due to potential metal-chelating issues with some of the substrates used in this study, a proposed ligand synthesis is discussed in which one of the methoxy groups of BrettPhos is replaced with a morpholine capable of occupying palladium's open coordination site during its catalytic cycle. A final C-N bond formation study focuses on the cross-coupling of aryl halides with amidine salts. For this cross-coupling, a methodology has been developed that can be applied to various electron-rich, electron-poor, and electron-neutral substrates. Furthermore, the products of this cross-coupling can be used for a subsequent electrocyclization through a reaction with aldehyde, demonstrating that a relatively simple two-pot methodology can be used to make relatively complex substrates with pharmaceutical applications. Both amides and amidines are common moieties in drug-like molecules because of the various biological activities of these functional groups. Potential medicinal applications of the developed cross-coupling of amidine salts with aryl halides methodology are described. Thus, methodologies for various palladium-catalyzed, C-N cross-couplings as well as a potential ligand synthesis to be used for palladium catalysis are herein discussed.
by Camille Z. McAvoy.
S.B.
Schmeckpeper, Benjamin Arthur. "Outdoor augmented reality n-th game editing suite." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41669.
Full textIncludes bibliographical references (p. 57).
OARnGES was developed to be a comprehensive Augmented Reality game development tool. Augmented Reality provides players a view of the real world augmented with virtual characters and information. Augmented Reality has proved to be a valuable educational tool, but bridging the gap between experimental game engines and in-class deployment has proved difficult. OARnGES attempts to close that gap by removing the technical barriers of game development. The Augmented Reality engine framework is still in flux and OARnGES provides a stabilizing layer between the developer and the platform.
by Benjamin Arthur Schmeckpeper.
M.Eng.
McMahill, Dan. "Automatic calibration of modulated fractional-N frequency synthesizers." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/16780.
Full textIncludes bibliographical references (p. 145-148).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
The focus of this research has been the development of a low power, radio frequency transmitter architecture. Specifically, a technique for in service automatic calibration of a modulated phase locked loop (PLL) frequency synthesizer has been developed. Phase/frequency modulation is accomplished by modulating the feedback divide value in a phase locked loop frequency synthesizer. A digital precompensation filter is used to extend the modulation bandwidth by canceling the low-pass transfer function of the PLL. The automatic calibration circuit maintains accurate matching between the digital precompensation filter and the analog PLL transfer function across process and temperature variations. The automatic calibration circuit, which is the main contribution of this thesis, operates while the transmitter is in service. This online calibration eliminates the need for production calibration and periodic down time for calibration cycles.
(cont.) In addition the calibration circuitry provides greater accuracy in the modulation than what is possible via offline methods of calibration. The calibration circuit works with M-ary GFSK as well as 2 level GFSK. The automatic calibration circuit has been implemented in two forms to prove its operation. The first version is a circuit board level implementation with a center frequency of around 60 MHz. The second implementation of the system is in a full custom 0.6 ,Lm BiCMOS integrated circuit. The integrated circuit contains the complete synthesizer with automatic calibration and operates in the 1.88 GHz frequency band used by the Digital European Cordless Telephone (DECT) standard. A data rate of 2.5 Mbps using 2 level GFSK and 5.0 Mbps using 4 level GFSK has been achieved with a power consumption of 78 mW.
by Daniel R. McMahill.
Ph.D.
Lee, Walter (Walter Cheng-Wan). "Garbarge collection for the autopilot C system." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/35454.
Full textLin, Jeremy H. (Jeremy Huei) 1976. "An optimizing C compiler for DSP architectures." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/47889.
Full textIncludes bibliographical references (leaf 48).
by Jeremy H. Lin.
S.B.and M.Eng.
Camardo, Andrew T. "C-JUN N-TERMINAL KINASE INHIBITORY NANOTHERAPEUTICS FOR REGENERATIVE ELASTIC MATRIX REPAIR IN ABDOMINAL AORTIC ANEURYSMS." Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu1499868307678719.
Full textDavis, Eli Bristol. "Fast, compatible, complete memory safety For C programs." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/112860.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 95-97).
The lack of memory safety in C/C++ programs is one of, if not the, most persistent and costly sources of program exploits. Attacks based on memory corruption can range from the reading of private data to a complete hostile takeover of a process. While many solutions to this problem have been proposed, it is as of yet unsolved-as old memory corruption attacks are rendered obsolete, new attacks continually spring up. This lack of success is largely due to the trade-offs that memory safety solutions make between completeness, compatibility, and overhead. There no a single solution with all three properties, and a solution must have all three in order to once-and-for-all solve the lack of memory safety in C programs: If a solution is incomplete, attackers will find a workaround. Unless it is backwards compatible and low-overhead, it will not be deployed in production. My goal for this thesis was to take an existing system which is close to having all three properties, and add the missing property. I chose to work with SoftboundCETS an LLVM pass which is already complete and backwards compatible, but has high runtime overhead. In this thesis, I take SoftboundCETS and heavily optimize its runtimes, reducing its total overhead by half. I split the original pass into two separate passes (one to mark which instructions were to be instrumented and the second to do the actual instrumentation) and then insert several optimization passes between them. I test my results on selected benchmarks from SPEC2000 and SPEC2006, and create a virtual machine image which allows my results to be reliably reproduced. Lastly, I propose a number of further optimizations which would allow Softbound-CETS to achieve low enough overhead to be used in a mid-performance production system.
by Eli Bristol Davis.
M. Eng.
Coleman, Jesse J. "The design, construction, and implementation of an engineering software command processor and macro compiler /." Online version of thesis, 1995. http://hdl.handle.net/1850/12219.
Full textGreeley, Gregory L. (Gregory Lawrence). "The effects of voting algorithms on N-version software reliability." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14822.
Full textShi, Zhangsheng. "Strain engineering of Co-N-C catalyst toward enhancing the HER and ORR electrocatalytic activities." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/207078/8/Zhangsheng_Shi_Thesis.pdf.
Full textPevzner, Boris. "Transport and dielectric properties of thin fullerene (C₆₀) films." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/41403.
Full textParisot, Alexandre 1979. "Mode conversion current drive experiments on Alcator C-Mod." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40505.
Full textIncludes bibliographical references (p. 189-197).
In tokamak plasmas with multiple ion species, fast magnetosonic waves (FW) in the Ion Cyclotron Range of Frequency can mode convert to shorter wavelength modes at the Ion-Ion hybrid layer, leading to localized electron heating and current drive. Due to k1l upshifts associated with the poloidal magnetic field, only small net driven currents were predicted from mode converted Ion Bernstein Waves (IBW). As studied first by Perkins, and later confirmed experimentally with Phase Contrast Imaging measurements on Alcator C-Mod, poloidal field effects can also lead to mode conversion to Ion Cyclotron Waves (MCICW), on the low field side of the mode conversion layer. In this thesis, mode conversion current drive in the ICW-dominated regime is studied numerically and through experiments on Alcator C-Mod. Solving a dispersion relation for the mode converted waves in a slab geometry relevant to tokamak equilibria and in the finite Larmor radius limit, we find that mode conversion to Ion Cyclotron Waves is ubiquitous to high temperature conventional tokamaks, as a result of the central value for the safety factor qo 1. MCICWs are identified as kinetically modified Ion Cyclotron Waves in the regime w/kllVthe < 1. Full wave simulations with the TORIC code predict net currents can be driven by MCICW as a result of up-down asymmetries in the mode conversion process. Initial estimates with the Ehst-Karney parametrization indicated up to -- 100 kA could be driven for 3 MW input power in C-Mod plasmas. More accurate calculations, consistent with the polarization of MCICWs, were carried out by importing a quasilinear diffusion operator build from the TORIC fields in the Fokker-Planck code DKE, and predicted lower current drive efficiencies by a factor of 2.
(cont.) The TFTR discharges in 1996 where net MCCD currents were inferred experimentally from loop voltage differences were simulated with TORIC, which indicates mode conversion to ICW can account for the driven currents. Similar loop voltage experiments in D(3He) plasmas were attempted on Alcator C-Mod, but did not yield conclusive current drive measurements. The lack of control over Zeff in C-Mod, which is illustrative of ICRF operation in tokamaks with metallic walls, makes reaching optimal plasma conditions for MCCD difficult, and limits the range of parameters in which MCCD can be useful as a net current drive tool in C-Mod. Solving the current diffusion equation in the cylindrical limit and with sawtooth reconnection models, the large sawtooth oscillations in C-Mod plasmas were also found to complicate current relaxation and hinder the loop voltage analysis for small central driven currents inside the q = 1 surface. In separate experiments on Alcator C-Mod, sawtooth period changes were used to infer localized MCCD near the q = 1 surface. The mode conversion layer was swept outward through the q = 1 surface in D(3He) plasmas, and the sawtooth period was found to vary from 3 to 12 ms, which is consistent wih localized current drive and TORIC predictions. A similar evolution was found in heating and co-current drive phasing, which suggests net currents are driven with a symmetric antenna spectrum, as predicted by TORIC as a result of asymmetries in the mode conversion process. Simulations of the sawtooth cycle with the Porcelli trigger model indicate that TORIC currents can account for the sawtooth period evolution in heating phasing.
(cont.) Based on simulations of the saw-tooth cycle with the Porcelli trigger model, localized electron heating, which could also explain the experimental results, was found not to be dominant compared to the current drive effect. The experimental results demonstrate that, while not optimal, MCCD can be used for sawtooth control.
by Alexandre Parisot.
Ph.D.
Gruhl, Daniel F. "LibDsp, an object oriented C++ digital signal processing library." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/37539.
Full textIncludes bibliographical references (leaves 194-195).
by Daniel F. Gruhl.
M.Eng.
Gilleland, Cody Lee. "Large-scale transgenesis and nerve regeneration in C. elegans." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92654.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 143-150).
Caenorhabditis elegans (C. elegans) is a widely studied model organism due to their fully mapped neural network of 302 neurons and amenable genetics. Their small size and short life cycle allows for rapid studies to be conducted; however, after decades of use the manual methods of manipulation have remained relatively unchanged. This thesis details the development of largely automated, high-throughput, optical, robotic, and microfluidic technologies for laser neurosurgery screening and transgenesis in C. elegans. Discovery of molecular mechanisms and chemical compounds that enhance neuronal regeneration can lead to development of therapeutics to combat nervous system injuries and neurodegenerative diseases. By combining high-throughput microfluidics and femtosecond laser microsurgery, we demonstrate for the first time large-scale in vivo screens for identification of compounds that affect neurite regeneration. We performed over ten thousand microsurgeries at single-axon precision in the nematode C. elegans at a rate of 20 seconds per animal. Following surgeries, we exposed the animals to a hand-curated library of approximately one hundred small-molecules and identified chemicals that significantly alter neurite regeneration. In particular, we found that the PKC kinase inhibitor staurosporine strongly modulates regeneration in a concentration- and neuronal type-specific manner. Two structurally unrelated PKC inhibitors produce similar effects. We further show that regeneration is significantly enhanced by the PKC activator prostratin. Microinjection is an essential and widely used method for C. elegans transgenesis. Traditional injections have remained low-throughput for decades due to the laborious nature of the manual procedure which prohibit large-scale transgenesis screening. This thesis details the development of the C. elegans Automated Micro-Injection (CAMI) system for high-throughput microinjection which could be broadly useful for analysis of gene function through insertion of CRISPR/Cas9, cDNA or RNAi vectors in future applications. Using the standard roller phenotype the transformation efficiency in creating transgenic lines is comparable to manual injections. We demonstrate the utility of the system by deep-phenotyping a subset of 6 mutants backgrounds selected from the million mutant project. We introduced 12 fluorescent reporters to label 38 neurons in each genetic background in order to search for defects in development.
by Cody Lee Gilleland.
Ph. D.
Dong, Jin Xiang 1961. "Effect of silicon on the kinetics of Nb(C,N) precipitation during the hot working of steels." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31048.
Full textIt was found that the rate of Nb(C,N) precipitation in hot deformed austenite increases with Si concentration. This phenomenon is attributed to the increases in both the Nb diffusivity and the activities of C and N that result from Si addition. Based on the Dutta and Sellars model, an expression for the effect of strain rate on the precipitation start time has been proposed. The present experimental results can then be extrapolated to mill conditions.
Hu, Yujie. "Magnetic Diode-From p-n Junction to Ohmic Contact." VCU Scholars Compass, 2004. http://scholarscompass.vcu.edu/etd_retro/60.
Full textDeshpande, Ajay A. "A pseudo-polynomial time O(log² n)-approximation algorithm for art gallery problems." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36243.
Full textIncludes bibliographical references (p. 55-56).
In this thesis, we give a pseudo-polynomial time O(log² n)-approximation algorithm for a variant of the art gallery problem the point-guard problem. The point-guard problem involves finding the minimum number of points and their positions so that guards located at these points cover the interior of the art gallery. Our algorithm is pseudo-polynomial in the sense that it is polynomial in the number of walls of the art gallery but is possibly exponential in the number of bits required to represent the positions of the vertices of the art gallery. Our approach involves reducing the point-guard problem to a new problem of choosing a minimum number of guard-locations from a finite set obtained by a special subdivision procedure. The new problem has the optimal solution at most three times the optional solution of the point-guard problem. We further reduce the new problem to the set cover problem and obtain an approximate solution to the set cover problem.
by Ajay A. Deshpande.
S.M.
Jovanovic, Natalija Zorana. "Microstructured tungsten thermophotovoltaic selective emitters c by Natalija (Zorana) Jovanović." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44445.
Full textIncludes bibliographical references (p. 71-74).
This research investigates the fabrication, modeling, characterization, and application of tungsten two-dimensional (2D) photonic crystal (PhC) structures as selective emitters and means of achieving higher efficiencies in thermophotovoltaic (TPV) energy conversion systems. Important aspects of the fabrication process are researched, developed, and rigorously characterized, focusing on dimensional reliability, precision, and repeatability of the processes. A major contribution in the form of tungsten reactive ion etch (RIE) characterization is provided with detailed parameters and second-order influences on etch rate, smoothness, and mask erosion. Optical characterization of our prototypes is found to be in excellent agreement with simulation, and has provided an experimental confirmation of selective emitter performance. We show that selective emitters can substantially increase spectral efficiency, providing as much as three times the radiative power density of planar tungsten. We include the first measurement of 96% combined efficiency of a selective emitter and a dielectric stack mirror for TPV system applications.
Sc.D.
Kemp, Charles C. (Charles Clark) 1972. "A platform for visual learning dc by Charles C. Kemp." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/47416.
Full textHolland, Wesley. "A FRAMEWORK FOR AUTOMATICALLY GENERATING OPTIMIZED DIGITAL DESIGNS FROM C-LANGUAGE LOOPS." MSSTATE, 2008. http://sun.library.msstate.edu/ETD-db/theses/available/etd-04012008-162427/.
Full textKind, Gisela, and Louise Svennberg. "En jämförelse mellan PHP och C# i .Net." Thesis, Jönköping University, JTH, Computer and Electrical Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-9555.
Full textIn this report we compare the two programming languages PHP and C# in .Net. They are both used to create dynamic websites and on the web there's a debate going on about which of these languages you're recommended to use. With this report we want to make ourselves a more scientific base of which of these languages that is the most used language and which languages that are the most suitable for creating dynamic websites. We have two purposes with this report:
1. To compare the usage of the programming languages C# in .Net and PHP at web agencies, advertising agencies and combinded agencies in Sweden today.
2. To get a better insight in the languages partly theoretical and partly through making a practical comparison of how you program in those languages.
We have chosen to use four methods to reach our purposes; interviews, survey, lite-rature study and practical work. To among else find out which of PHP and C# in .Net that are the most common language, at web agencies, advertising agencies and combined agencies in Sweden today, we created a survey which we sent out to 100 companies in five counties. The interviews were done before the survey was designed since they were the foundation for the questions in the survey. All theoretical background is built on our literature study but we also got a little help from our literature study during our practical work. During our practical work we created two similar websites, one in each language to practically to be able to compare how the both codes are written and to make ourselves an opinion about how it feels to program in the both languages.
From the survey we found out that PHP is the most common language at the different types of agencies that we studied. We also found out that the companies who answered the survey believes that PHP still will be the most common language in Sweden in year 2015 of the two studied languages PHP and C# in .Net.
The survey also showed that good qualities in PHP are among others the simplicity, open source and platform independent. Worse qualities in PHP are that it lacks in troubleshooting, has low performance and too many versions.
We think that PHP overall is the easier language to program in, in comparison with C# in .Net since the way you write the code in PHP feels more understandable and logical. Many of the advantages and disadvantages we experienced consists with the agencies opinions regarding PHP, but also with the opinions regarding C# in .Net since it's fast, compiled and a well structured language. Worse qualities in C# in .Net we experienced are that it's own by Microsoft, less spread and has complicated code.
The conclusions of this study is that PHP is the most used programming language at the web agencies, advertising agencies and the combined agencies that this study included, that the both programming languages differ from eachother more than we predicted both theoretical and programmatically and PHP is better suited for less com-plicated programming while C# in .Net is more suited for advanced programming.
Parisot, Alexandre 1979. "Design of an ICRF fast matching system on Alcator C-Mod." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30095.
Full textIncludes bibliographical references (p. 125-127).
In Ion Cyclotron Radiofrequency Heating (ICRH) for tokamaks, fast variations of the antenna loading impedance limit flexible and robust high-power operations. In this thesis, novel solutions for real-time matching and reduction of these variations are investigated and studied for implementation on the Alcator C-Mod tokamak. Load tolerant prematching networks are reviewed and a prototype configuration for E-antenna is proposed. By maintaining low voltage standing wave ratio in the network for a wide range of loading conditions, it could allow robust high power operations without the need of fast matching. However, typical conditions could create current imbalance effects ; the performance of the system could be degraded and the phasing between the antenna affected, with side-effects on the overall behavior of the antenna in plasma. Another possible option for real-time matching uses ferrite loaded transmission lines, whose electrical length could be varied over timescales as fast as a few milliseconds. A potential ferrite material is identified and experimentally characterized in a small-scale low power experiment. This leads to design guidelines for a high power ferrite phase shifter and a fast-matching network using such tuners.
by Alexandre Parisot.
S.M.
Miller, Robert C. (Robert Chisolm). "A type-checking preprocessor for Cilk 2, a multithreaded C language." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36987.
Full textIncludes bibliographical references (p. 37-38).
by Robert C. Miller.
M.Eng.
Virza, Madars. "SNARKs for C : verifying program executions succinctly and in zero knowledge." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87953.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 69-72).
We present a proof system that allows efficient verification of NP statements, given proofs produced by an untrusted yet computationally-bounded prover. Our system is publicly verifiable: after a trusted third-party has generated a proving key and a verification key, anyone can use the proving key to generate non-interactive proofs for adaptively-chosen NP statements, and the proofs can be verified by anyone using the verification key. Moreover, our system is statistically zero-knowledge and the generated public parameters are reusable. The NP-complete language we choose is the correct execution of programs on TinyRAM, a minimalistic (nondeterministic) random-access machine that we design. Together with TinyRAM port of gcc compiler this achieves the first practical realization of a zero-knowledge Succinct Non-interactive ARgument of Knowledge (zk-SNARK) for program executions, in the preprocessing model. This cryptographic primitive is a powerful solution for delegating N P computations, and enjoys many features not achieved by primitives implemented in prior works, most importantly, succinct verification and support for arbitrary computations. Our approach builds on recent theoretical work in the area of outsourced verified computation. We present efficiency improvements and implementations of the two main ingredients: 1. A transformation that, given as input a C program, outputs a circuit whose satisfiability encodes the correct execution of the program. We leverage nondeterminism to make the generated circuit's size merely quasilinear in the size of the computation; in particular, we efficiently handle arbitrary loops, control flow, and random-memory accesses. This is in contrast with existing "circuit compilers", which produce circuits of quadratic size. 2. A transformation that, given as input a linear PCP for verifying satisfiability of circuits, outputs a corresponding SNARK. Furthermore, by building on recent work about quadratic span programs, using suitable choices of finite field and FFT algorithms, we give a very efficient implementation of a zero-knowledge linear PCP: linear-time query generation and quasilinear-time prover.
by Madars Virza.
S.M.
McLeod, Bruce Daniel 1968. "Performance evaluation of N-processor Time Warp using stochastic activity networks." Thesis, The University of Arizona, 1993. http://hdl.handle.net/10150/278314.
Full textGreenberg, David Ross. "The physics and technology of the InAlAs/n⁺-InP heterostructure field-effect transistor." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/37763.
Full textIncludes bibliographical references (p. 135-140).
by David Ross Greenberg.
Ph.D.
Westman, Joakim, and Teodor Marinescu. "C, C++, Java och Python : En prestandajämförelse mellan fyra programmeringsspråk." Thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-2304.
Full textShepard, Thomas Donavon. "Fast wave ion cyclotron resonance heating experiments on the Alcator C tokamak." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14402.
Full textGriffin, Patrick (Patrick Robert). "C-Flow : a compiler for statically scheduled message passing in parallel programs." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/38329.
Full textIncludes bibliographical references (p. 95-96).
Performance improvement in future microprocessors will rely more on the exploitation of parallelism than increases in clock frequency, leading to more multi-core and tiled processor architectures. Despite continuing research into parallelizing compilers, programming multiple instruction stream architectures remains difficult. This document describes C-Flow, a compiler system enabling statically-scheduled message passing between programs running on separate processors. When combined with statically-scheduled, low-latency networks like those in the MIT Raw processor, C-Flow provides the programmer with a simple but comprehensive messaging interface that can be used from high-level languages like C. The use of statically-scheduled messaging allows for fine-grained (single-word) messages that would be quite inefficient in the more traditional message passing systems used in cluster computers. Such fine-grained parallelism is possible because, as in systolic array machines, the network provides all of the necessary synchronization between tiles. On the Raw processor, C-Flow reduces development complexity by allowing the programmer to schedule static messages from a high-level language instead of using assembly code. C-Flow programs have been developed for arrays with 64 or more processor tiles and hve demonstrated performance within twenty percent of hand-optimized assembly.
by Patrick Griffin.
M.Eng.
Chanda, Sashi Kumar. "INVESTIGATION OF DEFECTS IN N-TYPE 4H-SIC AND SEMI-INSULATING 6H-SIC USING PHOTOLUMINESCENCE SPECTROSCOPY." MSSTATE, 2005. http://sun.library.msstate.edu/ETD-db/theses/available/etd-07072005-102232/.
Full textLe, Quang H. M. Eng (Quang Huy)Massachusetts Institute of Technology. "G A N mask R-CNN : instance semantic segmentation benefits from generative adversarial networks." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/129896.
Full textCataloged from student-submitted PDF of thesis.
Includes bibliographical references (pages 33-35).
In designing instance segmentation ConvNets that reconstruct masks, segmentation is often taken as its literal definition -assigning label to every pixel- for defining the loss functions. That is, using losses that compute the difference between pixels in the predicted (reconstructed) mask and the ground truth mask -a template matching mechanism. However, any such instance segmentation ConvNet is a generator, so we can lay the problem of predicting masks as a GANs game framework: We can think the ground truth mask is drawn from the true distribution, and a ConvNet like Mask R-CNN is an implicit model that infers the true distribution. In GANs terms, Mask R-CNN is the generator who reconstructs a mask as the fake one. We then send the fake mask and the real (ground truth) one to a discriminator (critic). By playing a min-max game, we want Mask R-CNN to fool the critic, and the critic to distinguish between real and fake masks. In this way, we take the advantage of a region proposal network (implemented in Mask R-CNN) to design a generator, and the benefit of a critic network to design a better loss function as opposed to a template matching one. We discuss how we utilize the GANs training stability regiments in practice to make this concept works. We show this GANs framework performs better than the original Mask R-CNN. Furthermore, we show the results give crisper boundaries - a traditional challenge of ConvNets where there is a trade-off between having higher level of semantics and finer boundaries.
by Quang H. Le.
M. Eng.
M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
Xia, Guangrui 1976. "Investigation of mechanisms and influencing processing factors on mobility enhancement in strained Si n-MOSFETs." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/87898.
Full textPerrott, Michael H. (Michael Henderson). "Techniques for high data rate modulation and low power operation of fractional-N frequency synthesizers." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10187.
Full textIncludes bibliographical references (p. 183-188).
by Michael Henderson Perrott.
Ph.D.
Agarwal, Abhinav. "Comparison of high level design methodologies for algorithmic IPs : Bluespec and C-based synthesis." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/46612.
Full textIncludes bibliographical references (leaves 37-39).
High level hardware design of Digital Signal Processing algorithms is an important design problem for decreasing design time and allowing more algorithmic exploration. Bluespec is a Hardware Design Language (HDL) that allows designers to express intended microarchitecture through high-level constructs. C-based design tools directly generate hardware from algorithms expressed in C/C++. This research compares these two design methodologies in developing hardware for Reed-Solomon decoding algorithm under area and performance metrics. This work illustrates that C-based design flow may be effective in early stages of the design development for fast prototyping. However, the Bluespec design flow produces hardware that is more customized for performance and resource constraints. This is because in later stages, designers need to have close control over the hardware structure generated that is a part of HDLs like Bluespec, but is difficult to express under the constraints of sequential C semantics.
by Abhinav Agarwal.
S.M.
Hutchison, Luke A. D. (Luke Alexander Daysh) 1976. "Whole-organism integrative expressome for C. elegans enables in silico study of developmental regulation." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/66005.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (p. 117-119).
The C. elegans nematode has been extensively studied as a model organism since the 1970s, and is the only organism for which the complete cell division tree and the genome are both available. These two datasets were integrated with a number of other datasets available at WormBase.org, such as the anatomy ontology, gene expression profiles extracted from 8ooo peer-reviewed papers, and metadata about each gene, to produce the first ever whole-organism, cell-resolution map of gene expression across the entire developmental timeline of the organism, with the goal to find genomic features that regulate cell division and tissue differentiation. Contingency testing was performed to find correlations between thousands of gene attributes (e.g. the presence or absence of a specific 8-mer in the 3' UTR, the CG-content of the sequence upstream of the transcriptional start site, etc.) and thousands of cell attributes (e.g. whether cells that express specific genes die through apoptosis, whether cells become neurons or not, whether cells move in the anterior or posterior direction after division). The resulting database of contingency test scores allow us to quickly ask a large number of biologically-interesting questions, like, "Does the length of introns of expressed genes increase across the developmental timeline?"; "Across what period of development and in which cell types is this specific gene most active?"; "Do regulatory motifs exist that switch on or off genes in whole subtrees of the cell pedigree?"; "Which genes are most strongly implicated in apoptosis?", etc. This whole-organism expressome enables direct and powerful in silico analysis of development.
by Luke A. D. Hutchison.
Ph.D.