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Novel potentials for the simulation of polyethylene and other polymeric systems

Waksman, George
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 59 leaves; 1945360 bytes; 1946818 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
45.79%
Throughout the history of science, people have been developing models to explain reality. The advent of computer technology has made it possible to devise and implement incredibly complicated numerical models in a relatively short period of time; for example, three-body problems, impossible to solve analytically, becomes trivial to model with computers. Beyond three-body problems, computers have been instrumental in solving many-body problems, such as those encountered in the atomic interactions within materials. Since computer modeling of atomic systems does not predate computers, it is still in its childhood, requiring further investigations. In order to further the development of computer modeling and a general understanding of reality, novel model algorithms for the simulation of polymeric systems have been developed. The proposed algorithms are empirical in nature, having been derived from observed atomic and molecular behavior, owing little to subatomic theories. The algorithms were developed to model polyethylene but extensions are provided to allow possible generalization to any other polymeric system.; by George Waksman.; Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005.; Includes bibliographical references (leaf 19).

Auditory system comparisons between sand cats and other felid species : acoustic input admittance of ears and auditory brainstem responses

Chan, Howard F
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 82 leaves; 3531194 bytes; 3533557 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
45.81%
The sand cat, one species of the cat family, is found only in deserts and has unusually large ear canals and middle-ear air cavities. Recent work has shown that sand cat ears absorb acoustic power at low frequencies (<1 kHz) better than those of domestic cats (Huang et al. 2002). In this thesis, we test this hypothesis by comparing acoustic input- admittance, which determines acoustic power absorption, and thresholds of auditory- brainstem responses. In a zoo, measurements were made in 37 ears of 23 anesthetized specimens, including sand cats and five other felid species. Sand cats have lower mean thresholds at frequencies between 0.25 and 5 kHz by 6-9 dB than other felid species measured. However, the mean power absorption does not differ significantly. The results are consistent with the hypothesis that sand-cat hearing is unusually sensitive, but this specialization is not associated with increased power absorbed at the tympanic membrane.; by Howard F. Chan.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.; Includes bibliographical references (leaves 81-82).

Nanostructured Origami (TM) : stress-engineering of nanopatterned membranes to produce three-dimensional structures; Stress-engineering of nanopatterned membranes to produce three-dimensional structures

Arora, William Jay
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 127 p.
ENG
Relevância na Pesquisa
45.79%
Microdevice fabrication is done on the surface of polished flat semiconductor substrates with a series of material depositions, etches and lithography steps. These processes are inherently planar and well suited for the fabrication of billions of micrometer-thick transistors over 300 mm diameter substrates, but impractical for building vertically. This thesis presents a method of building three-dimensionally (3D) with existing planar fabrication technology: fabricate on a thin membrane, and then fold the membrane into a 3D structure. Material stresses patterned on a membrane will cause controlled bending. A simple demonstration is the bilayer, in which a stressed metal is deposited on a stress-free membrane. One challenge with this approach is to achieve very small fold radii for tight 3D packing. The solution presented here is helium ion implantation into the membrane, which creates a large localized stress that is capable of bending a 100 nm thick membrane around a 1 [mu]m radius without fracturing it. The energy and dose of the helium ions control the direction and angle of the fold, which is explained within a theoretical framework, and shown to agree with experiment. One application of stress-folding is a chemical sensor. Built as a 3D micro-switch...

Engineering the optical properties of subwavelength devices and materials

Anant, Vikas, 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 154 p.
ENG
Relevância na Pesquisa
45.83%
Many applications demand materials with seemingly incompatible optical characteristics. For example, immersion photolithography is a resolution enhancing technique used to fabricate the ever-shrinking nanostructures in integrated circuits but requires a material that has-at the same time--a large index of refraction and negligible optical loss. Other applications require devices that have optical properties that seem exorbitant given the constraints posed by the geometry, materials, and desired performance of these devices. The superconducting nanowire single-photon detector (SNSPD) is one such device that, on the one hand, needs to absorb and detect single telecom-wavelength photons (A = 1.55 pm) with near-perfect efficiency, but on the other hand, has an absorber that is subwavelength in its thickness (A/390). For both cases, it is simply not enough to look for alternative materials with the desired optical properties, because the materials may not exist in nature. In fact, it has become necessary to engineer the optical properties of these devices and materials using other means. In this thesis, we have investigated how the optical properties of materials and devices can be engineered for specific applications. In the first half of the thesis...

Research in Computer Science and Computer Engineering

Feldman, J. A. ; Merriam, C. W.
Fonte: University of Rochester. Computer Science Department. Publicador: University of Rochester. Computer Science Department.
Tipo: Relatório
ENG
Relevância na Pesquisa
65.85%
This report describes many of the computer related research efforts at the University of Rochester. The Department of Computer Science is involved in research in automatic programming, including very high level languages and data structures; machine perception; and in problem solving using combinations of traditional heuristic methods, artificial intelligence,and utility theory. The research of the Department of Electrical Engineering includes basic computer engineering research in the construction of computer systems and operating systems, research in image processing and in numerical methods, and research in production automation which is concerned with mechanical manufacturing and assembly, and is currently developing mathematical models of parts, raw materials and tools. In conjunction with other departments, Electrical Engineering is also using computers for biomedical applications including ultrasound diagnostic techniques for heart disease, and pattern recognition techniques for detection of cancer from PAP smears.

Research in Computer Science and Computer Engineering

Feldman, J. A. ; Merriam, C. W.
Fonte: University of Rochester. Computer Science Department. Publicador: University of Rochester. Computer Science Department.
Tipo: Relatório
ENG
Relevância na Pesquisa
65.85%
This report describes many of the computer related research efforts at the University of Rochester. The Department of Computer Science is involved in research in automatic programming, including very high level languages and data structures; machine perception; and in problem solving using combinations of traditional heuristic methods, artificial intelligence,and utility theory. The research of the Department of Electrical Engineering includes basic computer engineering research in the construction of computer systems and operating systems, research in image processing and in numerical methods, and research in production automation which is concerned with mechanical manufacturing and assembly, and is currently developing mathematical models of parts, raw materials and tools. In conjunction with other departments, Electrical Engineering is also using computers for biomedical applications including ultrasound diagnostic techniques for heart disease, and pattern recognition techniques for detection of cancer from PAP smears.

Research in Computer Science and Computer Engineering

Feldman, J. A. ; Merriam, C. W.
Fonte: University of Rochester. Computer Science Department. Publicador: University of Rochester. Computer Science Department.
Tipo: Relatório
ENG
Relevância na Pesquisa
55.83%
This report describes many of the computer related research efforts at the University of Rochester. The Department of Computer Science is involved in research in automatic programming, including very high level languages and data structures; machine perception; and in problem solving using combinations of traditional heuristic methods, artificial intelligence, and utility theory. The research of the Department of Electrical Engineering includes basic computer engineering research in the construction of computer systems and operating systems, research in image processing and in numerical methods, and research in production automation which is concerned with mechanical manufacturing and assembly, and is currently developing mathematical models of parts, raw materials and tools. In conjunction with other departments, Electrical Engineering is also using computers for biomedical applications including ultrasound diagnostic techniques for heart disease, and pattern recognition techniques for detection of cancer from PAP smears.

Research in Computer Science and Computer Engineering

Feldman, J. A. ; Merriam, C. W.
Fonte: University of Rochester. Computer Science Department. Publicador: University of Rochester. Computer Science Department.
Tipo: Relatório
ENG
Relevância na Pesquisa
55.83%
This report describes many of the computer related research efforts at the University of Rochester. The Department of Computer Science is involved in research in automatic programming, including very high level languages and data structures; machine perception; and in problem solving using combinations of traditional heuristic methods, artificial intelligence, and utility theory. The research of the Department of Electrical Engineering includes basic computer engineering research in the construction of computer systems and operating systems, research in image processing and in numerical methods, and research in production automation which is concerned with mechanical manufacturing and assembly, and is currently developing mathematical models of parts, raw materials and tools. In conjunction with other departments, Electrical Engineering is also using computers for biomedical applications including ultrasound diagnostic techniques for heart disease, and pattern recognition techniques for detection of cancer from PAP smears.

Research in Computer Science and Computer Engineering

Feldman, J. A. ; Merriam, C. W.
Fonte: University of Rochester. Computer Science Department. Publicador: University of Rochester. Computer Science Department.
Tipo: Relatório
ENG
Relevância na Pesquisa
55.83%
This report describes many of the computer related research efforts at the University of Rochester. The Department of Computer Science is involved in research in automatic programming, including very high level languages and data structures; machine perception; and in problem solving using combinations of traditional heuristic methods, artificial intelligence, and utility theory. The research of the Department of Electrical Engineering includes basic computer engineering research in the construction of computer systems and operating systems, research in image processing and in numerical methods, and research in production automation which is concerned with mechanical manufacturing and assembly, and is currently developing mathematical models of parts, raw materials and tools. In conjunction with other departments, Electrical Engineering is also using computers for biomedical applications including ultrasound diagnostic techniques for heart disease, and pattern recognition techniques for detection of cancer from PAP smears.

International Comparative Study : Engineering Education in India

World Bank
Fonte: Washington, DC Publicador: Washington, DC
EN_US
Relevância na Pesquisa
45.79%
The central and state governments of India have been pursuing several reforms in the higher education sector. In engineering education, the government has already embarked on several reforms within the current legislative framework. Given this dynamic momentum, the engineering education sector in India is expected to receive a significant boost over the next few years. It is therefore timely to take stock and review the position of the sector internationally. This study thus aims to provide the Ministry of Human Resource Development (MHRD), the All India Council for Technical Education (AICTE), and relevant stakeholders with key facts, reliable data, and the results of relevant international comparisons to establish a common ground and to help in measuring the performance of the current engineering education system in India. The government also recognizes the importance of lessons that may be learned from the other Brazil, the Russian Federation, India, and China (BRIC) countries, and these countries were therefore selected for the comparison. This report is organized as follows: section one gives introduction; section two briefly discusses the background of both general higher education and engineering education in India. Section three reviews earlier comparative studies on international engineering education. Section four describes the scope of the study. Section five explains the methodology of data collection and identifies the data sources. Section six outlines the analysis of the collected data and the findings. Section seven presents conclusions. The appendixes describe the engineering education systems of the various countries examined in the study...

An engineering context for software engineering

Riehle, Richard D.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Relevância na Pesquisa
45.82%
New engineering disciplines are emerging in the late Twentieth and early Twenty-first Century. One such emerging discipline is software engineering. The engineering community at large has long harbored a sense of skepticism about the validity of the term software engineering. During most of the fifty-plus years of software practice, that skepticism was probably justified. Professional education of software developers often fell short of the standard expected for conventional engineers; software practice seemed to be a "hit or miss" approach; and the available knowledge, tools, and language designs were not sufficiently mature to support an engineering model for software practice. Much progress has occurred in recent years, due to improved tools and languages along with a better ways of reasoning about and designing software products. This progress has contributed to the increase in success in the way software is developed and managed. However, even with a growing number of software successes, there are still enough horror-stories to reinforce the skepticism of the larger engineering community. Those skeptics continue to ask the reasonable question, "Where is the engineering in software engineering?" The primary contribution of this dissertation is to establish a foundation for answering the question at the end of the previous paragraph. Another contribution is a foundation for answering that same question for other emerging engineering disciplines. We call this foundation a context. The context is derived from: a study of conventional engineering...

Dynamic Spectrum Allocation for Cognitive Radio Networks: A Comprehensive Optimization Approach

Sabbah, AYMAN
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
45.77%
In Cognitive Radio Networks (CRNs), the role of the Medium Access Control (MAC) layer is very important since it enables Secondary Users (SUs) to access the spectrum without affecting Primary Users' (PUs) communications. SUs' and PUs' geometry has an effect on the performance of the spectrum sharing algorithms. Also, SUs' mobility changes the topology of the network as well as interference between the PUs and SUs. The scenario of multiuser multichannel CRNs introduces new challenges such as co-channel interference. Consequently, the power budget should be allocated to the SUs subject to specific constraints. Hence, different SUs will have different power and interference limits depending on the activity of PUs and on which SUs will be causing co-channel interference to each other. In addition, enabling Energy Harvesting (EH) in CRNs is promising to extend their lifetime so that the hybrid interweave/underlay access scheme is adopted, which means that SUs can access the active and non-active PU bands. In this thesis, I propose new optimal and suboptimal Dynamic Spectrum Allocation (DSA) algorithms that employ an interweave/underlay access scheme. I also study the impact of the following factors: mobility of the SUs, spectrum mobility...

Computer-assisted de-identification of free-text nursing notes

Douglass, Margaret, 1981-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 70 leaves; 3923649 bytes; 3926254 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
45.82%
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...

Intelligence by design : principles of modularity and coordination for engineering complex adaptive agents

Bryson, Joanna Joy, 1965-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 338 p.; 27329196 bytes; 27328955 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
45.81%
All intelligence relies on search - for example, the search for an intelligent agent's next action. Search is only likely to succeed in resource-bounded agents if they have already been biased towards finding the right answer. In artificial agents, the primary source of bias is engineering. This dissertation describes an approach, Behavior-Oriented Design (BOD) for engineering complex agents. A complex agent is one that must arbitrate between potentially conflicting goals or behaviors. Behavior-oriented design builds on work in behavior-based and hybrid architectures for agents, and the object oriented approach to software engineering. The primary contributions of this dissertation are: 1. The BOD architecture: a modular architecture with each module providing specialized representations to facilitate learning. This includes one pre-specified module and representation for action selection or behavior arbitration. The specialized representation underlying BOD action selection is Parallel-rooted, Ordered, Slip-stack Hierarchical (POSH) reactive plans. 2. The BOD development process: an iterative process that alternately scales the agent's capabilities then optimizes the agent for simplicity, exploiting tradeoffs between the component representations. This ongoing process for controlling complexity not only provides bias for the behaving agent...

Design principles and patterns for computer systems that are simultaneously secure and usable

Garfinkel, Simson
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 472 p.; 29543936 bytes; 31405031 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
45.78%
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...

ADAM : a decentralized parallel computer architecture featuring fast thread and data migration and a uniform hardware abstraction

Huang, Andrew S. (Andrew Shane)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 256 p.; 8574353 bytes; 8574153 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
45.82%
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...

A two-year Software Engineering M.Sc. degree designed under the Bologna Declaration Principles

Fernandes, João M.; Machado, Ricardo J.
Fonte: IEEE Computer Society Press Publicador: IEEE Computer Society Press
Tipo: Conferência ou Objeto de Conferência
Publicado em /10/2006 ENG
Relevância na Pesquisa
55.81%
This paper presents and discusses the syllabus of a second cycle degree on Software Engineering in which any student that finishes any undergraduate Computing degree (Computer Engineering, Computer Science, Information Systems, Information Technology, and Software Engineering) can enroll. In the first year, the degree is composed of two 30 ECTS modules, one dedicated to software analysis and design and the other devoted to software quality and management. Each module is composed of five curricular units, being one of them dedicated to the experimental integration of the module’s topics. The second year allows two different paths to be followed by the students. The professional path includes a 30 ECTS industrial project, while in the scientific path students must write a 45 ECTS master dissertation. The degree is mainly structured to consider the Bologna Declaration that is now being used in Europe to recast all university degrees. Additionally, we also considered the Software Engineering 2004 Curriculum Guidelines and the Knowledge Areas described in the SWEBOK.

Specification and Verification of Uplink Framework for Application of Software Engineering using RM-ODP

Salahddine, Krit; Jalal, Laassiri; Said, El Hajji
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/04/2012
Relevância na Pesquisa
45.77%
This paper present a survey and discussion of the Reference Model for Open Distributed Processing (RM-ODP) viewpoints; oriented approaches to requirements engineering viewpoint and a presentation of new work in the application wireless mobile phone, this area which has been designed with practical application using the Unified Modelling Language (UML)/VHDL_AMS (VHSIC Hardware Description Language Analog and Mixed-Signal). We mainly focus on rising and fulling time, action, uplink behaviour constraints (sequentiality, non determinism and concurrency constraints).We discuss the practical problems of introducing viewpoint; oriented requirements engineering into industrial software engineering practice and why these have prevented the widespread use of existing approaches. The goal of this article is to check the uplink path using the MIC (Microphone amplifier) with all analog inputs, and check the amplifier gain. This paper provides an example of using the Uplink Framework to build a comprehensive, good solution for Application Wireless Mobile Phone. Finally, we discuss how well this approach addresses some outstanding problems in requirements engineering (RE) and the practical industrial problems of introducing new requirements engineering methods.; Comment: 6 pages

Knowledge Engineering Technique for Cluster Development

Sureephong, Pradorn; Chakpitak, Nopasit; Ouzrout, Yacine; Neubert, Gilles; Bouras, Abdelaziz
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/12/2007
Relevância na Pesquisa
45.75%
After the concept of industry cluster was tangibly applied in many countries, SMEs trended to link to each other to maintain their competitiveness in the market. The major key success factors of the cluster are knowledge sharing and collaboration between partners. This knowledge is collected in form of tacit and explicit knowledge from experts and institutions within the cluster. The objective of this study is about enhancing the industry cluster with knowledge management by using knowledge engineering which is one of the most important method for managing knowledge. This work analyzed three well known knowledge engineering methods, i.e. MOKA, SPEDE and CommonKADS, and compares the capability to be implemented in the cluster context. Then, we selected one method and proposed the adapted methodology. At the end of this paper, we validated and demonstrated the proposed methodology with some primary result by using case study of handicraft cluster in Thailand.

Role of engineers in the creation of engineering drawings - past, present and future

Castro-Cedeno, Mario
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Conferência ou Objeto de Conferência Formato: 85149 bytes; application/pdf
EN
Relevância na Pesquisa
45.8%
A change in technology can redefine roles in society. Skills that were previously considered specialties and/or optional can become required for the general population. Some recent examples include typing and drafting. Neither skill was expected from engineers before the widespread availability of personal computers. Secretaries performed the overwhelming majority of typing, and drafting technicians were available in sufficient numbers to do the drafting. Both were considered necessary support personnel in all engineering organizations. Recently, however, the adoption of personal computers has made typing and drafting expected and necessary skills for every engineer. The reason is that the number of typists and designers have decreased steadily during the last 20 years as engineering organizations reaped the benefits of the investment in personal computers that increased workforce efficiency. Some of the reduction in support personnel can be explained by increased efficiency but, in addition, today most engineering organizations expect engineers to perform tasks previously assigned to support personnel. One implication of decreasing numbers of drafting technicians is that, increasingly, recent engineering graduates are expected to perform in such a role without the benefit of lengthy on-the-job training...