Patents Assigned to Massachusetts Institute of Technology, a Massachusetts Corporation
  • Publication number: 20040143176
    Abstract: Tracking a motion of a body by obtaining two types of measurements associated with the motion of the body, one of the types including acoustic measurement. An estimate of either an orientation or a position of the body is updated based on one of the two types of measurement, for example based on inertial measurement. The estimate is then updated based on the other of the two types of measurements, for example based on acoustic ranging. The invention also features determining range measurement to selected reference devices that are fixed in the environment of the body.
    Type: Application
    Filed: December 23, 2003
    Publication date: July 22, 2004
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventor: Eric M. Foxlin
  • Publication number: 20040093467
    Abstract: A methodology for designing a distributed shared-memory system, which can incorporate adaptation or selection of cache protocols during operation, guarantees semantically correct processing of memory instructions by the multiple processors. A set of rules includes a first subset of “mandatory” rules and a second subset of “voluntary” rules such that correct operation of the memory system is provided by application of all of the mandatory rules and selective application of the voluntary rules. A policy for enabling voluntary rules specifies a particular coherent cache protocol. The policy can include various types of adaptation and selection of different operating modes for different addresses and at different caches. A particular coherent cache protocol can make use of a limited capacity directory in which some but not necessarily all caches that hold a particular address are identified in the directory.
    Type: Application
    Filed: December 19, 2002
    Publication date: May 13, 2004
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventors: Xiaowei Shen, Arvind Mithal, Lawrence Rogel
  • Publication number: 20040083343
    Abstract: A computer architecture that includes a hierarchical memory system and one or more processors. The processors execute memory access instructions whose semantics are defined in terms of the hierarchical structure of the memory system. That is, rather than attempting to maintain the illusion that the memory system is shared by all processors such that changes made by one processor are immediately visible to other processors, the memory access instructions explicitly address access to a processor-specific memory, and data transfer between the processor-specific memory and the shared memory system. Various alternative embodiments of the memory system are compatible with these instructions. These alternative embodiments do not change the semantic meaning of a computer program which uses the memory access instructions, but allow different approaches to how and when data is actually passed from one processor to another.
    Type: Application
    Filed: October 21, 2003
    Publication date: April 29, 2004
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventors: Arvind Mithal, Xiaowei Shen, Lawrence Rogel
  • Publication number: 20040052215
    Abstract: A method for specifying and synthesizing a synchronous digital circuit by first accepting a specification of an asynchronous system in which stored values are updated according to a set of state transition rules. For instance, the state transition rules are specified as a Term Rewriting System (TRS) in which each rule specifies a number of allowable state transitions, and includes a logical precondition on the stored values and a functional specification of the stored values after a state transition in terms of the stored values prior to the state transition. The specification of the asynchronous circuit is converted into a specification of an synchronous circuit in which a number of state transitions can occur during each clock period.
    Type: Application
    Filed: July 22, 2003
    Publication date: March 18, 2004
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventors: Arvind Mithal, James C. Hoe
  • Publication number: 20040033359
    Abstract: A coated nanocrystal capable of light emission includes a substantially monodisperse nanoparticle selected from the group consisting of CdX, where x=S, Se, Te and an overcoating of ZnY, where Y=S, Se, uniformly deposited thereon, said coated nanoparticle characterized in that when irradiated the particles exhibit photoluminescence in a narrow spectral range of no greater than about 60 nm, and most preferably 40 nm, at full width half max (FWHM). The particle size of the nanocrystallite core is in the range of about 20 Å to about 125 Å, with a deviation of less than 10% in the core. The coated nanocrystal exhibits photoluminescence having quantum yields of greater than 30%.
    Type: Application
    Filed: August 19, 2003
    Publication date: February 19, 2004
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventors: Moungi Bawendi, Klaus F. Jensen, Bashir O. Dabbousi, Javier Rodriguez-Viejo, Frederic Victor Mikulec
  • Publication number: 20030209105
    Abstract: A method of manufacturing a nanocrystallite from a M-containing salt forms a nanocrystallite. The nanocrystallite can be a member of a population of nanocrystallites having a narrow size distribution and can include one or more semiconductor materials. Semiconducting nanocrystallites can photoluminesce and can have high emission quantum efficiencies.
    Type: Application
    Filed: June 6, 2003
    Publication date: November 13, 2003
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventors: Moungi Bawendi, Nathan E. Stott
  • Publication number: 20030045816
    Abstract: Tracking a motion of a body by obtaining two types of measurements associated with the motion of the body, one of the types including acoustic measurement. An estimate of either an orientation or a position of the body is updated based on one of the two types of measurement, for example based on inertial measurement. The estimate is then updated based on the other of the two types of measurements, for example based on acoustic ranging. The invention also features determining range measurement to selected reference devices that are fixed in the environment of the body.
    Type: Application
    Filed: June 25, 2002
    Publication date: March 6, 2003
    Applicant: Massachusetts Institute of Technology, a Massachusetts Corporation
    Inventor: Eric M. Foxlin
  • Publication number: 20030027288
    Abstract: Methods of identifying compounds that disrupt aggregation of aggregation-disposed polypeptides, such as huntingtin or beta-amyloid protein, are disclosed. Furthermore, an artificial polypeptide that contains an extended polyglutamine region and DNA that encodes the polypeptide are also disclosed.
    Type: Application
    Filed: July 12, 2002
    Publication date: February 6, 2003
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventors: David E. Housman, Elizabeth A. Preisinger, Aleksey G. Kazantsev
  • Publication number: 20020191929
    Abstract: A device having at least one dielectric inner core region in which electromagnetic radiation is confined, and at least two dielectric outer regions surrounding the inner core region, each with a distinct refractive index. The outer regions confine electromagnetic radiation within the inner core region. The refractive indices, the number of outer regions, and thickness of the outer regions result in a reflectivity for a planar geometry that is greater than 95% for angles of incidence ranging from 0° to at least 80° for all polarizations for a range of wavelengths of the electromagnetic radiation. In exemplary embodiments, the inner core region is made of a low dielectric material, and the outer regions include alternating layers of low and high dielectric materials. In one aspect of the invention, the device is a waveguide, and in another aspect the device is a microcavity.
    Type: Application
    Filed: August 1, 2002
    Publication date: December 19, 2002
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventors: Yoel Fink, Shanhui Fan, Edwin Thomas, Chiping Chen, John Joannopoulos
  • Publication number: 20020163645
    Abstract: All-optical bit phase sensors that utilize nonlinear interferometers are described. An all-optical bit phase sensor that utilizes an optical fiber and a detector optically coupled to the core of the fiber, perpendicular to the longitudinal direction of the core, is described. In addition, an electrooptic bit phase sensor that utilizes a semiconductor diode and an electrical detector electrically coupled to the active layer is described. Electrooptical and all-optical phase lock loops, optical processors, and optical networks that utilize these bit phase sensing are also described.
    Type: Application
    Filed: May 14, 2002
    Publication date: November 7, 2002
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventors: Katherine L. Hall, Kristin A. Rauschenbach
  • Publication number: 20020150326
    Abstract: A method produces a wavelength shift into an optical siqnal. The method includes producing a coherent temporal array of optical signals (CTAS) from an incoming optical siqnal and broadening the signals of the CTAS to produce a interference pattern. The broadening results from transmitting the CTAS or the incoming optical signal through a dispersive medium. The method also includes selectively transmitting a peak of the interference pattern. The transmitted peak has a selected wavelength shift with respect to the incoming optical siqnal.
    Type: Application
    Filed: May 30, 2002
    Publication date: October 17, 2002
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventors: Farhad Hakimi, Hosain Hakimi, Katherine L. Hall
  • Publication number: 20020061164
    Abstract: A method introduces variable time offsets into a stream of optical pulses. The method includes receiving a plurality of coherent optical pulses, receiving a plurality of control signals, and forming a coherent pulse array (CPA) from each pulse in response to one of the received control signals. Temporal spacings between pulses of each CPA are responsive to the associated one of the received control signals. For optical control signals, response times can be very short. The method further includes transmitting each pulse through a dispersive optical medium. The act of transmitting makes pulses of each CPA overlap to form an interference pattern.
    Type: Application
    Filed: November 8, 2001
    Publication date: May 23, 2002
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventors: Katherine L. Hall, Hosain Hakimi, Farhad Hakimi, Daniel T. Moriarty, Kristin A. Rauschenbach
  • Publication number: 20010015842
    Abstract: An optical bit rate for communication systems. The optical bit rate converter converts an ultra-high speed optical data stream to a lower rate optical data stream. In one embodiment, the optical bit rate converter converts the ultra-high speed optical data stream to a lower rate optical data stream that can be detected and processed electronically. The optical rate converter includes a buffer presenting a repeating optical data bit pattern, an optical sampler presenting an optical sampling bit stream, and an optical correlator. The optical correlator has a first input in communication with the output of the buffer and a second input in communication with the output of the optical sampler. The optical correlator produces a rate-converted optical data bit stream at its output in response to the repeating optical data bit pattern produced by the buffer and the optical sampling bit stream produced by the optical sampler.
    Type: Application
    Filed: December 18, 2000
    Publication date: August 23, 2001
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventors: Naimish S. Patel, Katherine L. Hall, John D. Moores, Kristin A. Rauschenbach, Steven G. Finn, Richard A. Barry
  • Patent number: 5366686
    Abstract: A method for producing an article including a refractory compound by infiltrating a preform with a liquid infiltrant and initiating a reaction between the preform and the liquid infiltrant to establish a reaction front which propagates in a direction opposite to the direction of flow of the liquid infiltrant is provided, as are articles prepared according to this method.
    Type: Grant
    Filed: March 19, 1993
    Date of Patent: November 22, 1994
    Assignee: Massachusetts Institute of Technology, a Massachusetts Corporation
    Inventors: Andreas Mortensen, David C. Dunand