Ali Motamedi

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Recommended by Milind Buddhikot This paper addresses the problem of optimal channel selection for spectrum-agile low-powered wireless networks in unlicensed bands. The channel selection problem is formulated as a multiarmed bandit problem enabling us to derive the optimal selection rules. The model assumptions about the interfering traffic that motivates(More)
Radio Frequency Identification (RFID) based systems have been used in different applications in the Architecture, Engineering, Construction, Owner and Operator (AECOO) industry. Applications are mainly designed for specific lifecycle stage and serve the needs of only one of the stakeholders. This would increase the cost and the labor for adding and removing(More)
Photonic Analog-to-Digital Conversion (ADC) has a long history. The premise is that the superior noise performance of femtosecond lasers working at optical frequencies enables us to overcome the bottleneck set by jitter and bandwidth of electronic systems and components. We discuss and demonstrate strategies and devices that enable the implementation of(More)
—Opportunistic Spectrum Access (OSA) allows unlicensed secondary networks to share licensed spectrum in space and time, but only when licensed users are not using the spectrum. Thus this novel spectrum management technique started drawing the attention of researchers recently. Although many interesting approaches have been proposed, most techniques are(More)
Sampling rates of high-performance electronic analog-to-digital converters (ADC) are fundamentally limited by the timing jitter of the electronic clock. This limit is overcome in photonic ADC's by taking advantage of the ultra-low timing jitter of femtosecond lasers. We have developed designs and strategies for a photonic ADC that is capable of 40 GSa/s at(More)
Accurate conversion of wideband multi-GHz analog signals into the digital domain has long been a target of analog-to-digital converter (ADC) developers, driven by applications in radar systems, software radio, medical imaging, and communication systems. Aperture jitter has been a major bottleneck on the way towards higher speeds and better accuracy.(More)
Radiotherapy treatment planning requires a localization of the tumor within the patient. This is challenging to accomplish for microscopic infiltrative spread of disease that is not visible on current imaging modalities. Prime examples for infiltrative tumors are gliomas. With the help of mathematical models, common growth characteristics of gliomas, which(More)
The frequency-sampling method is widely used to accommodate nonlinear laser tuning in swept-wavelength interferometric techniques such as optical frequency domain reflectometry (OFDR) and swept-wavelength optical coherence tomography (OCT). In this paper we analyze the frequency-sampling method and identify two sources of sampling errors. One source of(More)