by Eric J. Mitchell.; Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.; Includes bibliographical references (leaf 57).; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
by Jack C. Kwok.; Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.; Pages 100-101 blank.; Includes bibliographical references (p. 98-99).; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Parallel shared-memory machines with hundreds or thousands of processor-memory nodes have been built; in the future we will see machines with millions or even billions of nodes. Associated with such large systems is a new set of design challenges. Many problems must be addressed by an architecture in order for it to be successful; of these, we focus on three in particular. First, a scalable memory system is required. Second, the network messaging protocol must be fault-tolerant. Third, the overheads of thread creation, thread management and synchronization must be extremely low. This thesis presents the complete system design for Hamal, a shared-memory architecture which addresses these concerns and is directly scalable to one million nodes. Virtual memory and distributed objects are implemented in a manner that requires neither inter-node synchronization nor the storage of globally coherent translations at each node. We develop a lightweight fault-tolerant messaging protocol that guarantees message delivery and idempotence across a discarding network. A number of hardware mechanisms provide efficient support for massive multithreading and fine-grained synchronization.; (cont.) Experiments are conducted in simulation, using a trace-driven network simulator to investigate the messaging protocol and a cycle-accurate simulator to evaluate the Hamal architecture. We determine implementation parameters for the messaging protocol which optimize performance. A discarding network is easier to design and can be clocked at a higher rate...
by Jeffrey Hastings Lang.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1980.; Includes bibliographical references.
by Guy Lewis Steele, Jr.; Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1980.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Bibliography: leaves 365-371.
by Thomas R. Hegg, Jr.; Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1983.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING; Bibliography: leaves 101-103.
by Deborah Lynn Estrin.; Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1985.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Bibliography: leaves 231-236.
by Christine M. Bohner.; Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1986.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING; Bibliography: leaf 74.
by Robert W. Baldwin.; Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1987.; Includes bibliographical references.; Supported by the Defense Advanced Research Projects Agency of the Department of Defense, monitored by the Office of Naval Research. N00014-83-K-0125
This thesis describes the redesign of a Byzantine-resilient, quad-redundant computer to remove proprietary hardware components. The basic architecture consists of four Commercial Off-The-Shelf (COTS) processors in a completely-connected network of point-to-point ethernet connections. In particular, the focus of this thesis is an algorithm that combines clock synchronization and communications between fault containment regions by inferring relative clock skew from the arrival time of expected messages. Both a failsafe and a fault-tolerant algorithm are discussed, though the fault-tolerant algorithm is not fully analyzed. The performance of a prototype and the failsafe synchronization algorithm are discussed.; by Reuben Marbell Sterling.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Includes bibliographical references (p. 155-156).
This thesis explores the use of entangled states in quantum computation and quantum information science. Entanglement, a quantum phenomenon with no classical counterpart, has been identified as an important and quantifiable resource in many areas of theoretical quantum information science, including quantum error correction, quantum cryptography, and quantum algorithms. We first investigate the equivalence classes of a particular class of entangled states (known as graph states due to their association with mathematical graphs) under local operations. We prove that for graph states corresponding to graphs with neither cycles of length 3 nor 4, the equivalence classes can be characterized in a very simple way. We also present software for analyzing and manipulating graph states. We then study quantum error-correcting codes whose codewords are highly entangled states. An important area of investigation concerning QECCs is to determine which resources are necessary in order to carry out any computation on the code to an arbitrary degree of accuracy, while simultaneously maintaining a high degree of resistance to noise. We prove that transversal gates, which are designed to prevent the propagation of errors through a system, are insufficient to achieve universal computation on almost all QECCs. Finally...
Medical researchers are legally required to protect patients' privacy by removing personally identifiable information from medical records before sharing the data with other researchers. Different computer-assisted methods are evaluated for removing and replacing protected health information (PHI) from free-text nursing notes collected in the hospital intensive care unit. A semi-automated method was developed to allow clinicians to highlight PHI on the screen of a tablet PC and to compare and combine the selections of different experts reading the same notes. Expert adjudication demonstrated that inter-human variability was high, with few false positives and many false negatives. A preliminary automated de-identification algorithm generated few false negatives but many false positives. A second automated algorithm was developed using the successful portions of the first algorithm and incorporating other heuristic methods to improve overall performance. A large de-identified collection of nursing notes was re-identified with realistic surrogate (but unprotected) dates, serial numbers, names, and phrases to form a "gold standard" reference database of over 2600 notes (approximately 340,000 words) with over 1800 labeled instances of PHI. This gold standard database of nursing notes and the Java source code used to evaluate algorithm performance will be made freely available on the Physionet web site in order to facilitate the development and validation of future de-identification algorithms.; by Margaret Douglass.; Thesis (M. Eng.)--Massachusetts Institute of Technology...
This thesis proposes a programmable toolkit for building image filters to make the concepts of basic image processing accessible and engaging to children. The toolkit was developed in the context of Scratch, a media-centric programming environment intended for children. For this thesis, I redesigned the image manipulation framework in Scratch to 'open the black box' of image processing. Through user testing done with children, it was shown that the new framework sufficiently exposed the image-processing concepts so that children were able to create their own compelling image-processing algorithms. Although this framework was not ideal for the Scratch programming environment, the concepts explored in this work can be used in classrooms that teach introductory computer programming through media computation, or in a separate programming environment for novices which focuses on basic image processing.; by Evelyn Eastmond.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.; Includes bibliographical references (p. 55).
Fonte: Electronic Systems Laboratory, Dept. of Electrical Engineering and Computer Science, Massachusetts Institute of TechnologyPublicador: Electronic Systems Laboratory, Dept. of Electrical Engineering and Computer Science, Massachusetts Institute of Technology
by Francisco de As?Ros Per?; Bibliography: p.175-176.; Prepared under Advanced Research Project Agency Contract N00014-75-C-1183. Originally presented as the author's thesis, (M.S.) in the M.I.T. Dept. of Electrical Engineering and Computer Science, 1976.
It is widely believed that security and usability are two antagonistic goals in system design. This thesis argues that there are many instances in which security and usability can be synergistically improved by revising the way that specific functionality is implemented in many of today's operating systems and applications. Specific design principles and patterns are presented that can accomplish this goal. Patterns are presented that minimize the release of confidential information through remnant and remanent data left on hard drives, in web browsers, and in documents. These patterns are based on a study involving the purchase of 236 hard drives on the secondary market, interviews conducted with organizations whose drives had been acquired, and through a detailed examination of modern web browsers and reports of information leakage in documents. Patterns are presented that enable secure messaging through the adoption of new key management techniques. These patterns are supported through an analysis of S/MIME handling in modern email clients, a survey of 469 Amazon.com merchants, and a user study of 43 individuals. Patterns are presented for promoting secure operation and for reducing the danger of covert monitoring. These patterns are supported by the literature review and an analysis of current systems.; (cont.) In every case considered...
The furious pace of Moore's Law is driving computer architecture into a realm where the the speed of light is the dominant factor in system latencies. The number of clock cycles to span a chip are increasing, while the number of bits that can be accessed within a clock cycle is decreasing. Hence, it is becoming more difficult to hide latency. One alternative solution is to reduce latency by migrating threads and data, but the overhead of existing implementations has previously made migration an unserviceable solution so far. I present an architecture, implementation, and mechanisms that reduces the overhead of migration to the point where migration is a viable supplement to other latency hiding mechanisms, such as multithreading. The architecture is abstract, and presents programmers with a simple, uniform fine-grained multithreaded parallel programming model with implicit memory management. In other words, the spatial nature and implementation details (such as the number of processors) of a parallel machine are entirely hidden from the programmer. Compiler writers are encouraged to devise programming languages for the machine that guide a programmer to express their ideas in terms of objects, since objects exhibit an inherent physical locality of data and code. The machine implementation can then leverage this locality to automatically distribute data and threads across the physical machine by using a set of high performance migration mechanisms.; (cont.) An implementation of this architecture could migrate a null thread in 66 cycles - over a factor of 1000 improvement over previous work. Performance also scales well; the time required to move a typical thread is only 4 to 5 times that of a null thread. Data migration performance is similar...
In this work a system that automates the process of people counting to determine what effects "just-in-time" messages have on motivating behavior is described. The system is designed to permit automatic study of the impact of motivational messages on people's stair use. A projector presents a point-of-decision message to passers-by choosing between a set of stairs and an escalator while a computer vision algorithm counts each type of traffic. Preliminary results of the effects of messages displayed in a Boston area subway station are discussed. The system is designed to be easily moved to different locations with minimal change to the setup and algorithm. Results from an initial trail showed a 4.3% increase in stair usage (p < .001), demonstrating both the viability of the measurement technology and the potential of point-of-decision messaging to change behavior.; by Jacob A. Hyman.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.; Includes bibliographical references (p. 121-125).