Other

USA As Represented by Secretary of the Navy

California Institute of Technology

The Aerospace Corporation

Hen-Geul Yeh

Babak Hassibi

Charles C Wang

Shipong Norman Yeh

Hsien-Yang Yeh

Wei-Hua Lu

Yuan-Kwei Chang

Ru-Yao Wang

Centralized controllers for a photovoltaic-enabled distribution grid are described herein. Photovoltaic cells may generate electricity that may be supplied to the distribution grid, which may experience unexpected abnormal power loads. The controllers utilize photovoltaic inverters connected to the photovoltaic cells to optimize the performance of the grid by absorbing or injecting reactive power. These controllers are particularly efficient in handling unexpected abnormal power loads.

Controllers for photovoltaic-enabled distribution grid

Real-time detection of high-impedance faults in a distribution circuit is described. The real-time detection of high-impedance faults includes two steps. First, adaptive soft denoising is employed to perform a filtering process on a healthy dataset, and to determine a threshold. This reduces the rate of false alarms. Second, faulty datasets are prefiltered via adaptive soft denoising, then the denoised signals are processed via discrete wavelet transform to perform high-impedance fault detection using the threshold.

Real-time detection of high-impedance faults

A system and method for reducing ICI in multicarrier systems is disclosed. The system uses a primary transmission path to transmit a first signal using the same techniques as conventional OFDM and a second transmission path to transmit a conjugate of the first signal. The differing transmission paths can be implemented on separate channels via a variety of multiplexing and/or diversity techniques.

Method and apparatus for canceling intercarrier interference through conjugate transmission for multicarrier communication systems

A parallel orthogonal frequency division multiplexed (OFDM) communications system includes a transmitter and receiver, the transmitter having a parallel fast Fourier transform (FFT) module operating in parallel to a conventional inverse fast Fourier transform (IFFT) module for providing respective orthogonal outputs received by the receiver. The receiver has a parallel IFFT module and a conventional FFT module for providing respective orthogonal outputs. The respective orthogonal outputs are combined to form a composite signal that provides improved insensitivity to relative frequency offsets and Doppler frequency offsets. The parallel FFT and IFFT modules in the OFDM communication system provides improved signal diversity and performance in the presence of relative frequency offsets and Doppler frequency offsets, and provides improved tracking capability for the receiver with backward compatibility.

Parallel orthogonal frequency division multiplexed communication system

A system for locating a vehicle that is parked in a parking lot, a parking garage or on a street. The system comprises two separate signal generator/processor circuits, each circuit being contained in a module, one being a hand-held locator module and the other, a receive/response module that is installed in a vehicle. Both modules, when activated by user, communicate with the other by means of specially encoded radio signals. To find a parked vehicle, a user merely presses a pushbutton on the locator module which transmits a high frequency search signal. In response, the receive/response module emits a direction indicating signal to the locator module, which then displays the direction and elevation of the vehicle with respect to the user location. Provision is made for the receive/response module to operate without a connection to a vehicle battery if necessary, allowing the module to be used portably. The system is small in size, inexpensive and easy to use.

Parked vehicle location finder

A method for nodulizing silicon crystals in casting Aluminum-(8-12%)Silicon alloys is described. An initial alloy melt is refined by addition of a master alloy containing elements of titanium, phosphorous, boron, zirconium and rare earths to the initial molten alloy, and then through conventional heat treatment and aging. Testing the alloys shows that the nodulized silicon crystals are blunted in shape and well distributed, resulting in a high resistance to wear and high ultimate tensile strength at room temperature and at 300 deg. C. Machinability of the Al-Si alloys is also greatly improved by the process.

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Cypress, CA, United States of America

Hen-Geul Yeh