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Carrier-assisted differential detection

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Light(Science & Applications) 2020年第1期9卷 1835-1843页

作者： william Shieh Chuanbowen Sun Honglin Ji Department of Electrical and Electronic Engineering The University of MelbourneParkville VIC3010Australia

To overcome power fading induced by chromatic dispersion in optical fiber communications,optical field recovery is a promising solution for direct detection short-reach applications,such as fast-evolving data center interconnects(DCIs).To date,various direct detection schemes capable of optical field recovery have been proposed,including Kramers−Kronig(KK)and signal−signal beat interference(SSBI)iterative cancellation(IC)***,they are all restricted to the single sideband(SSB)modulation format,thus conspicuously losing half of the electrical spectral efficiency(SE)compared with double sideband(DSB)***,SSB suffers from the noise folding issue,requiring a precise optical filter that complicates the receiver *** such,it is highly desirable to investigate the field recovery of DSB signals via direct *** this paper,for the first time,we propose a novel receiver scheme called carrier-assisted differential detection(CADD)to realize optical field recovery of complex-valued DSB signals via direct ***,CADD doubles the electrical SE compared with the KK and SSBI IC receivers by adopting DSB modulation without sacrificing receiver ***,by using direct detection without needing a precise receiver optical filter,CADD can employ cost-effective uncooled lasers as opposed to expensive temperature-controlled lasers in coherent *** proposed receiver architecture opens a new class of direct detection schemes that are suitable for photonic integration analogous to homodyne receivers in coherent detection.

关键词： receiver precise coherent

An Overview of MODIS Radiometric Calibration and Characterization

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Advances in Atmospheric Sciences 2006年第1期23卷 69-79页

作者： Xiaoxiong XIONG william BARNES Earth Sciences Directorate NASA/Goddard Space Flight Center Greenbelt MD 20771 USA University of Maryland Baltimore County Baltimore MD 21250 USA

The Moderate Resolution Imaging Spectroradiometer （MODIS） is one of the key instruments for NASA＇s Earth Observing System （EOS）, currently operating on both the Terra and Aqua satellites. The MODIS is a major advance over the previous generation of sensors in terms of its spectral, spatial, and temporal resolutions. It has 36 spectral bands： 20 reflective solar bands （RSB） with center wavelengths from 0.41 to 2.1 μm and 16 thermal emissive bands （TEB） with center wavelengths from 3.7 to 14.4 μm, making observations at three spatial resolutions： 250 m （bands 1-2）, 500 m （bands 3-7）, and lkm （bands 8-36）. MODIS is a cross-track scanning radiometer with a wide field-of-view, providing a complete global coverage of the Earth in less than 2 days. Both Terra and Aqua MODIS went through extensive pre-launch calibration and characterization at various levels. In orbit, the calibration and characterization tasks are performed using its on-board calibrators （OBCs） that include a solar diffuser （SD） and a solar diffuser stability monitor （SDSM）, a v-grooved flat panel blackbody （BB）, and a spectro-radiometric calibration assembly （SRCA）. In this paper, we present an overview of MODIS calibration and characterization activities, methodologies, and lessons learned from pre-launch characterization and in-orbit operation. Key issues discussed in this paper include in-orbit efforts of monitoring the noise characteristics of the detectors, tracking the solar diffuser and optics degradations, and updating the sensor＇s response versus scan angle. The experiences and lessons learned through MODIS have played and will continue to play major roles in the design and characterization of future sensors.

关键词： EOS remote sensing Terra Aqua MODIS sensor calibration radiometry

EIGENFREQUENCY ANALYSIS OF CABLE STRUCTURES WITH INCLINED CABLES

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Applied Mathematics and Mechanics(English Edition) 2006年第1期27卷 37-49页

作者： william Paulsen Greg Slayton Department of Computer Science and Mathematics Arkansas State University Arkansas 72467 USA

The approximate eigenfrequencies for the in-plane vibrations of a cable structure consisting of inclined cables, together with point masses at various points were computed. It was discovered that the classical transfer matrix method was inadequate for this task, and hence the larger exterior matrices were used to determine the eigenfrequency equation. Then predictions of the dynamics of the general cable structure based on the asymptotic estimates of the exterior matrices were made.

关键词： eigenfrequencies transfer matrices exterior matrices cable structures

Modelling sediment transport processes in macro-tidal estuary

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Science China(Technological Sciences) 2009年第11期52卷 3368-3375页

作者： Rauen william B. Hydro-environmental Research Centre School of Engineering Cardiff University Parade Cardiff CF24 3AA UK

This paper outlines a numerical modeling study to predict the sediment transport processes in a macro-tidal estuary, namely the Mersey Estuary, UK. An integrated numerical model study is conducted to investigate the interaction between the hydrodynamic, morphological and sediment transport processes occurring in the estuary. The numerical model widely used in environmental sediment transport studies worldwide, namely ECOMSED is used to simulate flow and sediment transport in estuary. A wetting and drying scheme is proposed and applied to the model, which defines "dry" cells as regions with a thin film of fluid O (cm). The primitive equations are solved in the thin film as well as in other regular wet cells. A model for the bed load transport is included in the code to account for the dynamics of the mobile bed boundary. The bed evolution due to bed load transport which is calculated according to van Rijn (1984a) is obtained by solving the sediment mass-balance equation. An estuary-related laboratory flume experiment is used to verify the model. Six sets of field measured hydrodynamic data are used to verify the corresponding predictions of the model, with the model-predicted water elevations and salinity levels generally agreeing well with the field measurements. The numerical model results show that in the Mersey Estuary both the tidal level and river discharge affect significantly the sediment transport. Reasonable agreement between the model results and field data has been obtained, indicating that the model can be used as computer-based tool for the environment management of estuarine system.

关键词： hydraulic modelling sediment transport estuary ECOMSED flooding and drying

Best Constants for Moser-Trudinger Inequalities,Fundamental Solutions and One-Parameter Representation Formulas on Groups of Heisenberg Type

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Acta Mathematica Sinica,English Series 2002年第2期18卷 375-390页

作者： COHN william S. Department of Mathematics.Wayne State University.Detroit.MI 48202 USA

We derive the explicit fundamental solutions for a class of degenerate(or singular)one- parameter subelliptic differential operators on groups of Heisenberg(H)*** extends the result of Kaplan for the sub-Laplacian on H-type groups,which in turn generalizes Folland's result on the Heisenberg *** an application,we obtain a one-parameter representation formula for Sobolev functions of compact support on H-type *** choosing the parameter equal to the homogeneous dimension Q and using the Mose-Trudinger inequality for the convolutional type operator on stratified groups obtained in[18].we get the following theorem which gives the best constant for the Moser- Trudiuger inequality for Sobolev functions on H-type groups. Let G be any group of Heisenberg type whose Lie algebra is generated by m left invariant vector fields and with a q-dimensional *** Q=m+2q.Q'=Q-1/Q and Then. with A_Q as the sharp constant,where ▽G denotes the subelliptic gradient on G. This continues the research originated in our earlier study of the best constants in Moser-Trudinger inequalities and fundamental solutions for one-parameter subelliptic operators on the Heisenberg group [18].

关键词： Heisenberg group Groups of Heisenberg type Sobolev inequalities Moser-Trudinger inequalities Best constants One-Parameter representation formulas Fundamental solutions

Current progress in innovative engineerec antibodies

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Protein & Cell 2018年第1期9卷 86-120页

作者： william R. Strohl BiStro Biotech Consulting Bridgewater NJ 08807 USA

As of May 1, 2017, 74 antibody-based molecules have been approved by a regulatory authority in a major market. Additionally, there are 70 and 575 antibody- based molecules in phase III and phase 1/11 clinical trials, respectively. These total 719 antibody-based clinical stage molecules include 493 naked IgGs, 87 antibody- drug conjugates, 61 bispecific antibodies, 37 total Fc fusion proteins, 17 radioimmunoglobulins, 13 antibody fragments, and 11 immunocytokines. New uses for these antibodies are being discovered each year. For oncol- ogy, many of the exciting new approaches involve anti- body modulation of T-cells. There are over 80 antibodies in clinical trials targeting T cell checkpoints, 26 T-cell- redirected bispecific antibodies, and 145 chimeric anti- gen receptor （CAR） cell-based candidates （all currently in phase I or II clinical trials）, totaling more than 250 T cell interacting clinical stage antibody-based candi- dates. Finally, significant progress has been made recently on routes of delivery, including delivery of proteins across the blood-brain barrier, oral delivery to the gut, delivery to the cellular cytosol, and gene- and viral-based delivery of antibodies. Thus, there are cur- rently at least 864 antibody-based clinical stage mole- cules or cells, with incredible diversity in how they are constructed and what activities they impart. These are followed by a next wave of novel molecules, approa- ches, and new methods and routes of delivery, demon- strating that the field of antibody-based biologics is very innovative and diverse in its approaches to fulfill their promise to treat unmet medical needs.

关键词： antibody clinical candidates engineered antibodies chimeric antigen receptors

Weak Gravity Conjecture and extremal black holes

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Science China(Physics,Mechanics & Astronomy) 2019年第11期62卷 69-86页

作者： william Cottrell Gary Shiu Pablo Soler Department of Physics University of WisconsinMadison WI53706USA Institut fur Theoretische Physik Universitat HeidelbergPhilosophenweg19Heidelberg D-69120Germany

Motivated by the desire to improve our understanding of the Weak Gravity Conjecture, we compute the one-loop correction of charged particles to the geometry and entropy of extremal black holes in 4D. We use the entropy function formalism to extend previous analysis that dealt with neutral particles, and obtain the corrections to the horizon entropy for different regimes of black hole masses. These corrections are small in general. They are furthermore reduced when supersymmetry is present, and disappear in N = 4 supergravity. We provide some speculative arguments that in a theory with only sub-extremal particles, classical Reissner-Nordstrom black holes actually possess an infinite microcanonical entropy, though only a finite amount is visible to an external observer, as shown by the horizon entropy computation.

关键词： black holes string theory entropy

A Dialectal Chinese Speech Recognition Framework

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Journal of Computer Science & Technology 2006年第1期21卷 106-115页

作者：李净郑方 william Byrne Dan Jurafsky Center for Speech Technology State Key Laboratory of Intelligent Technology and Systems Department of Computer Science and Technology Tsinghua University Beijing 100084 P.R. China Machine Intelligence Laboratory Cambridge University U.K. Center for Language and Speech Processing The Johns Hopkins University U.S.A. Department of Linguistics Stanford University U.S.A.

A framework for dialectal Chinese speech recognition is proposed and studied, in which a relatively small dialectal Chinese （or in other words Chinese influenced by the native dialect） speech corpus and dialect-related knowledge are adopted to transform a standard Chinese （or Putonghua, abbreviated as PTH） speech recognizer into a dialectal Chinese speech recognizer. Two kinds of knowledge sources are explored： one is expert knowledge and the other is a small dialectal Chinese corpus. These knowledge sources provide information at four levels： phonetic level, lexicon level, language level, and acoustic decoder level. This paper takes Wu dialectal Chinese （WDC） as an example target language. The goal is to establish a WDC speech recognizer from an existing PTH speech recognizer based on the Initial-Final structure of the Chinese language and a study of how dialectal Chinese speakers speak Putonghua. The authors propose to use contextindependent PTH-IF mappings （where IF means either a Chinese Initial or a Chinese Final）, context-independent WDC-IF mappings, and syllable-dependent WDC-IF mappings （obtained from either experts or data）, and combine them with the supervised maximum likelihood linear regression （MLLR） acoustic model adaptation method. To reduce the size of the multipronunciation lexicon introduced by the IF mappings, which might also enlarge the lexicon confusion and hence lead to the performance degradation, a Multi-Pronunciation Expansion （MPE） method based on the accumulated uni-gram probability （AUP） is proposed. In addition, some commonly used WDC words are selected and added to the lexicon. Compared with the original PTH speech recognizer, the resulting WDC speech recognizer achieves 10-18% absolute Character Error Rate （CER） reduction when recognizing WDC, with only a 0.62% CER increase when recognizing PTH. The proposed framework and methods are expected to work not only for Wu dialectal Chinese but also for other dialectal Chinese languages and

关键词： dialectal Chinese speech recognition initial or final (IF) IF-mapping rule pronunciation modeling small quantity of speech data

Preliminary study on the influence of in situ filter size in CFD-DEM transfer kernel

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Particuology 2020年第4期18卷 205-209页

作者： william D.Fullmer Jordan Musser National Energy Technology Laboratory MorgantownWV26507USA Leidos Research Support Team MorgantownWV26507USA

An unknown in coupled Eulerian-Lagrangian models for particle flow,such as CFD-DEM,which has received fairly little attention in the literature to date is the size of the filter width in the transfer *** work provides a preliminary glimpse at how this parameter can influence the solution in cold-flow,unbounded *** to previously published direct numerical simulation data is used to suggest an appropriate range for this parameter.

关键词： CFD-DEM High-resolution Lagrangian-Eulerian kernel