gebhart/patrepeval huggingface dataset:
Computationally Efficient Subspace-Based Method for Direction-of-Arrival Estimation Without Eigendecomposition (2004)

A computationally simple direction-of-arrival (DOA) estimation method with good statistical performance is attractive in many practical applications of array processing. In this paper, we propose a new computationally efficient subspace-based method without eigendecomposition (SUMWE) for the coherent narrowband signals impinging on a uniform linear array (ULA) by exploiting the array geometry and its shift invariance property. The coherency of incident signals is decorrelated through subarray averaging, and the null space is obtained through a linear operation of a matrix formed from the cross-correlations between some sensor data, where the effect of additive noise is eliminated. Consequently, the DOAs can be estimated without performing eigendecomposition, and there is no need to evaluate all correlations of the array data. Furthermore, the SUMWE is also suitable for the case of partly coherent or incoherent signals, and it can be extended to the spatially correlated noise by choosing appropriate subarrays. The statistical analysis of the SUMWE is studied, and the asymptotic mean-squared-error (MSE) expression of the estimation error is derived. The performance of the SUMWE is demonstrated, and the theoretical analysis is substantiated through numerical examples. It is shown that the SUMWE is superior in resolving closely spaced coherent signals with a small number of snapshots and at low signal-to-noise ratio (SNR) and offers good estimation performance for both uncorrelated and correlated incident signals.
Fast computation of finite-length MIMO MMSE decision feedback equalizers (2005)

We present a new fast algorithm for computing multi-input-multi-output (MIMO) minimum mean-square-error decision feedback equalizer (MMSE-DFE) taps. The new algorithm is obtained by identifying the feedforward equalizer solution as a well known expression encountered in fast recursive least squares (RLS) adaptive algorithms, and the feedback equalizer as a convolution of the feedforward equalizer with the channel. The proposed method is less complex, more structured, and more stable in finite precision than known algorithms in the literature, which rely on fast methods for Cholesky decomposition.
Efficient Generation of Models of Fed-Batch Fermentations for Process Design and Control (2016)

The paper presents a fast and efficient approach to the generation of process models for fed-batch fermentation processes. Elementary Modes (EM) with kinetic terms are used as macro-react ions in the model. A method based upon dynamic metabolic flux analysis (DMFA) is used to find an optimal selection of EM based on concentration measurements instead of reaction rates that must be calculated from the measurements. A multi-objective genetic algorithm is used to investigate the tradeoff between the number of EM and the difference of the estimated concentration profiles from the available measurements. Thus the number of macro-reactions for the model is kept small but the measured data are described sufficiently well by the selected EM. The influence of the process conditions on each macro-reaction rate are identified by a statistical analysis and kinetic expressions are fitted to the estimated evolutions by solving multiple simple optimization problems instead of a multi-dimensional large-scale nonlinear parameter optimization problem. The resulting process model provides a good fit of the measurement data. Provided that the data is generated by a systematic approach, e.g., using a design of experiments strategy, the modelling procedure provides models of adequate complexity that are valid within the so-called design space of the process.
Uniform Mesopore-Donated Zeolite Y Using Carbon Aerogel Templating (2003)

Zeolite Y of mesoporous channels has been synthesized using novel mesoporous carbon aerogels as template. It was characterized with X-ray powder diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis, and nitrogen adsorption/desorption. The pore size distribution with N2 adsorption shows the presence of mesopores and micropores whose average pore widths are ca. 10 and 0.75 nm, and pore volumes are 1.37 and 0.21 cm3 g-1, respectively. FE-SEM observation supports the presence of mesopores.
Commentary on human pluripotent stem cell-based blood–brain barrier models (2020)

In 2012, we provided the first published evidence that human pluripotent stem cells could be differentiated to cells exhibiting markers and phenotypes characteristic of the blood-brain barrier (BBB). In the ensuing years, the initial protocols have been refined, and the research community has identified both positive and negative attributes of this stem cell-based BBB model system. Here, we give our perspective on the current status of these models and their use in the BBB community, as well as highlight key attributes that would benefit from improvement moving forward.
Pentacene Organic Thin-Film Transistors with Dual-Gate Structure (2007)

We report on the fabrication of dual-gate pentacene organic thin-film transistors (OTFTs) using a plasma-enhanced atomic layer deposited (PEALD) 150 nm thick Al2O3 as a bottom gate dielectric and a 300 nm thick parylene or a PEALD 200 nm thick Al2O3 as both a top gate dielectric and a passivation layer. The threshold voltage (Vth) of OTFT with a 300 nm thick parylene as a top gate dielectric is changed from 4.7 V to 1.3 V and that with a PEALD 200 nm thick Al2O3 as a top gate dielectric is changed from 1.95 V to -9.8 V when the voltage bias of top gate electrode is changed from -10 V to 10 V. The change of Vth of OTFT with the dual-gate structure has been successfully understood by an analysis of electrostatic potential.
Peptidomimetic β-Secretase Inhibitors Comprising a Sequence of Amyloid-β Peptide for Alzheimer’s Disease (2015)

Alzheimer's disease is a grave social problem in an aging population. A major problem is the passage of drugs through the blood-brain barrier. This work tests the hypothesis that the conjugation of peptidomimetic β-secretase inhibitors with a fragment of amyloid-β peptide facilitates entrance into the central nervous system. HVR-3 (compound 4), one of the conjugation products, was found to be as potent as OM00-3, a known peptidomimetic inhibitor, 4-fold more selective toward β-secretase 1 in relation to β-secretase 2 and 3-fold more resistant to in vitro metabolization in human serum. Its intravenous administration to mice and Wistar rats generated an active metabolite recovered from the rodent's brains.
Toward Assessing and Improving the Quality of Stereo Images (2012)

Imaging systems have incorporated numerous technological innovations such as 3-D television and handheld devices. Despite these advances, these techniques still require the human eyes to refocus until the sense of depth perception is achieved by the observer. The more time this takes, the more eye muscles become fatigued and the brain tires from confusion. However, the exact intricacies involved are far more complex. To alleviate these problems, we introduce a learning framework that aims to improve the quality of stereo images. Instead of attempting to cover all factors that affect the quality of stereo images, such as image resolution, monitor response, viewing glass response, viewing conditions, viewer differences, and compression artifacts, we first introduce a set of universally relevant geometric stereo features for anaglyph image analysis based on feature point correspondence across color channels. We then build a regression model that effectively captures the relationship between the stereo features and the quality of stereo images and show that the model performs on par with the average human judge in our study. Finally, we demonstrate the value of the proposed quality model in two proposed applications where it is used to help enhance the quality of stereo images and also to extract stereo key frames from a captured 2-D video.
A cell‐free platform for rapid synthesis and testing of active oligosaccharyltransferases (2017)

Protein glycosylation, or the attachment of sugar moieties (glycans) to proteins, is important for protein stability, activity, and immunogenicity. However, understanding the roles and regulations of site-specific glycosylation events remains a significant challenge due to several technological limitations. These limitations include a lack of available tools for biochemical characterization of enzymes involved in glycosylation. A particular challenge is the synthesis of oligosaccharyltransferases (OSTs), which catalyze the attachment of glycans to specific amino acid residues in target proteins. The difficulty arises from the fact that canonical OSTs are large (>70 kDa) and possess multiple transmembrane helices, making them difficult to overexpress in living cells. Here, we address this challenge by establishing a bacterial cell-free protein synthesis platform that enables rapid production of a variety of OSTs in their active conformations. Specifically, by using lipid nanodiscs as cellular membrane mimics, we obtained yields of up to 420 μg/ml for the single-subunit OST enzyme, "Protein glycosylation B" (PglB) from Campylobacter jejuni, as well as for three additional PglB homologs from Campylobacter coli, Campylobacter lari, and Desulfovibrio gigas. Importantly, all of these enzymes catalyzed N-glycosylation reactions in vitro with no purification or processing needed. Furthermore, we demonstrate the ability of cell-free synthesized OSTs to glycosylate multiple target proteins with varying N-glycosylation acceptor sequons. We anticipate that this broadly applicable production method will advance glycoengineering efforts by enabling preparative expression of membrane-embedded OSTs from all kingdoms of life.
Prompt gamma correction for improved quantification in 82Rb PET (2008)

254 Objectives: The positron emitter 82Rb also emits a 777 keV prompt gamma (PG) in 14% of its β+ decays. This produces a true coincidence background, distinct from scatter, which, if left uncompensated, will lead to quantitative errors in cardiac perfusion images. These errors may exist in both 2D and 3D PET and are more important the poorer the system energy resolution is. We have implemented and validated a correction for this PG background. Methods: Because the PGs are uncorrelated in angle with the annihilation photons, the 82Rb PG background has a spatial distribution similar to random coincidences. We estimate a randoms sinogram from measured single event rates. This PG model is combined with a scatter sinogram estimated by the SSS algorithm, and the total background model is scaled to fit the tails of the measured data. Results: Because the PG background differs in shape from scatter, a background correction that includes only a scatter model, when fitted to the data, can be unstable, cause over-scaling of the scatter, and result in quantitative inaccuracies in the resulting image. However, we find 82Rb thorax phantom studies with the combined PG+scatter correction show quantitative accuracy comparable to conventional 18F studies. In six 82Rb cardiac patients scans on a Siemens Biograph PET/CT, PG fractions were 6-12%, while scatter fractions were 30-42%. The PG correction (PGC) was also robust for independently reconstructed gated cardiac studies. Conclusions: PGC improves quantitative accuracy in 82Rb cardiac studies and may reduce the potential for spurious uptake variations as well. For these reasons, PGC could be important for both quantitative and semi-quantitative CAD diagnosis, and should be employed for images in the normals database as well as for the clinical patient scans. Research Support: Data courtesy of Emory Crawford Long Hospital and Cardiovascular Imaging Technologies.
Wirtinger holography for near-eye displays (2019)

Near-eye displays using holographic projection are emerging as an exciting display approach for virtual and augmented reality at high-resolution without complex optical setups --- shifting optical complexity to computation. While precise phase modulation hardware is becoming available, phase retrieval algorithms are still in their infancy, and holographic display approaches resort to heuristic encoding methods or iterative methods relying on various relaxations. In this work, we depart from such existing approximations and solve the phase retrieval problem for a hologram of a scene at a single depth at a given time by revisiting complex Wirtinger derivatives, also extending our framework to render 3D volumetric scenes. Using Wirtinger derivatives allows us to pose the phase retrieval problem as a quadratic problem which can be minimized with first-order optimization methods. The proposed Wirtinger Holography is flexible and facilitates the use of different loss functions, including learned perceptual losses parametrized by deep neural networks, as well as stochastic optimization methods. We validate this framework by demonstrating holographic reconstructions with an order of magnitude lower error, both in simulation and on an experimental hardware prototype.
Low-complexity bit-parallel canonical and normal basis multipliers for a class of finite fields (2002)

We present a new low-complexity bit-parallel canonical basis multiplier for the field GF(2/sup m/) generated by an all-one-polynomial. The proposed canonical basis multiplier requires m/sup 2/-1 XOR gates and m/sup 2/ AND gates. We also extend this canonical basis multiplier to obtain a new bit-parallel normal basis multiplier.
Accessible Mannitol‐Based Amphiphiles (MNAs) for Membrane Protein Solubilisation and Stabilisation (2016)

Integral membrane proteins are amphipathic molecules crucial for all cellular life. The structural study of these macromolecules starts with protein extraction from the native membranes, followed by purification and crystallisation. Detergents are essential tools for these processes, but detergent-solubilised membrane proteins often denature and aggregate, resulting in loss of both structure and function. In this study, a novel class of agents, designated mannitol-based amphiphiles (MNAs), were prepared and characterised for their ability to solubilise and stabilise membrane proteins. Some of MNAs conferred enhanced stability to four membrane proteins including a G protein-coupled receptor (GPCR), the β2 adrenergic receptor (β2 AR), compared to both n-dodecyl-d-maltoside (DDM) and the other MNAs. These agents were also better than DDM for electron microscopy analysis of the β2 AR. The ease of preparation together with the enhanced membrane protein stabilisation efficacy demonstrates the value of these agents for future membrane protein research.
Performance of resonator fiber optic gyroscope using external-cavity laser stabilization and optical filtering (2014)

A bench-top resonator fiber optic gyroscope (RFOG) was assembled and tested, showing encouraging progress toward navigation grade performance. The gyro employed a fiber length of 19 meters of polarizing fiber for the sensing coil which was wound on an 11.5 cm diameter PZT cylinder. A bias stability of approximately 0.1 deg/hr was observed over a 2 hour timeframe, which is the best bias stability reported to date in an RFOG to our knowledge. Special care was taken to minimize laser phase noise, including stabilization to an optical cavity which was also used for optical filtering, giving angle random walk (ARW) values in the range of 0.008 deg/rt-hr. The ARW performance and bias stability are within 2x and 10x, respectively, of many civil inertial navigation grade requirements.
Dynamic Simulation Study on a Coal-Fired Power Plant Aided With Low-Temperature Solar Energy (2019)

Abstract The concept of coal-fired power generation aided with solar energy uses stable fossil energy to compensate the instability and intermittently of solar power and reduces the cost of concentrated solar power (CSP) by decreasing the large-scale heat storage and turbine systems of CSP. In this study, trough solar collector system (TSCS) was integrated into the low-pressure heater side of a 660 MW coal-fired power generation system. In the system in which the 6# LP heater is completely replaced by TSCS, the variation value of the steam extraction flowrate of the LP heaters and the turbine output power decrease with the reduction in loads from 100% to 60% THA, and the output power increases by approximately 1 MW under 100% THA. When TSCS completely replaces the 6# LP heater under the load of 75%, the effects of direct normal irradiance (DNI) increase and flow ratio decrease on the main operating parameters of solar-aided coal-fired power plant (SCPP) were studied. Results show that the step increase of DNI decreases the 5# steam extraction flowrate and increases the output power by nearly 3 MW. When the flow ratio decreases by 139.87 kg/s, the output power decreases by around 0.35 MW. The dynamic characteristics of SCPP under different parallel situations with the load of 75% were also studied. As the number of parallel stage increases, the decrement in 5# steam extraction flowrate and the increment in output power decrease. The response time also decreases. Our study aims to provide detailed references for the control system design and optimization of coal-fired power units aided with solar energy.
Optimal Random Sampling from Distributed Streams Revisited (2019)

We give an improved algorithm for drawing a random sample from a large data stream when the input elements are distributed across multiple sites which communicate via a central coordinator. At any point in time the set of elements held by the coordinator represent a uniform random sample from the set of all the elements observed so far. When compared with prior work, our algorithms asymptotically improve the total number of messages sent in the system as well as the computation required of the coordinator. We also present a matching lower bound, showing that our protocol sends the optimal number of messages up to a constant factor with large probability. As a byproduct, we obtain an improved algorithm for finding the heavy hitters across multiple distributed sites.
Search strategies for optimal multi-way number partitioning (2013)

The number partitioning problem seeks to divide a set of n numbers across k distinct subsets so as to minimize the sum of the largest partition. In this work, we develop a new optimal algorithm for multi-way number partitioning. A critical observation motivating our methodology is that a globally optimal k-way partition may be recursively constructed by obtaining suboptimal solutions to subproblems of size k − 1. We introduce a new principle of optimality that provides necessary and sufficient conditions for this construction, and use it to strengthen the relationship between sequential decompositions by enforcing upper and lower bounds on intermediate solutions. We also demonstrate how to further prune unpromising partial assignments by detecting and eliminating dominated solutions. Our approach outperforms the previous state-of-the-art by up to four orders of magnitude, reducing average runtime on the largest benchmarks from several hours to less than a second.
Exceeding Drilling Performance and Environmental Requirements with Potassium Silicate Based Drilling Fluid (2004)

Abstract Since the re-introduction of silicate based drilling fluids, the vast majority of wells have been formulated around sodium silicate. Somewhat surprising, it is only recently that potassium silicate has become the alkali silicate of choice for use on-land. Described are the chemistry, drilling and environmental performance of potassium silicate. Field results are presented for a series of wells drilled in British Columbia, Canada using a potassium silicate based drilling fluid. These results show that drilling objectives were exceeded and further demonstrated ease of disposal with minimum impact on the environment.
Photonic thermometry: upending 100 year-old paradigm in temperature metrology (2019)

For the past century, industrial temperature measurements have relied on resistance measurement of a thin metal wire or thin metal film whose resistance varies with temperature. Today’s resistance thermometers can routinely measure temperatures with uncertainties of 10 mK to 100 mK over a broad range of temperatures in varied settings ranging from a stove top to an industrial broiler to a nuclear power plant. However, for all their utility, resistance thermometers remain vulnerable to mechanical and thermal shock and attack from harsh chemicals. The resultant drift in sensor resistance necessitates frequent off-line, expensive, and time-consuming calibrations. These fundamental limitations of resistance thermometry, born of material properties, have generated considerable interest in developing photonic temperature sensors. Photonic approaches hold the promise of leveraging recent advances in frequency metrology and of achieving greater mechanical and environmental robustness. In recent years many groups including ours have demonstrated a suite of photonic devices including silicon photonic devices that can not only meet but exceed the state of art in temperature metrology
Reduction of NOx emissions using carbon and/or carbon containing species (1998)

Nitric oxide (NO) reduction by activated carbon at low temperatures (25--225 C) is investigated in this work. The experiments were carried out in a fixed bed reactor consisting of carbon particles (1--1.4 mm) through which a gaseous mixture containing a known concentration of NO in helium is passed through. It is observed that the pretreatment of the carbon at high temperatures (900--1,000 C) in an inert atmosphere enhances the amount of NO sorbed on the surface of carbon. Results indicate that NO is physically adsorbed at ambient temperatures and that the amount of physisorbed NO decreases with an increase in the temperature of isothermal sorption. Above ambient temperatures, sorption of NO by activated carbon involves both physical and chemical means with chemical sorption dominating at higher temperatures. These results indicate that chemical interaction between NO and carbon can also take place at low temperatures and activated carbon does show potential for NO reduction from flue gases at low temperatures (dust region). Temperature programmed desorption (TPD) was conducted on post-sorption carbon samples and it was observed that by heating the carbon bed up to a temperature of 400 C, nearly all physically adsorbed NO could be desorbed from the carbon surface.
Quantum Interference of Single Photons from Remote Nitrogen-Vacancy Centers in Diamond (2012)

We demonstrate quantum interference between indistinguishable photons emitted by two nitrogen-vacancy centers in distinct diamond samples separated by two meters. Macroscopic solid immersion lenses are used to enhance photon collection efficiency. Quantum interference is verified by measuring a value of the second-order cross-correlation function g((2))(0)=0.35±0.04<0.5. In addition, optical transition frequencies of two separated nitrogen-vacancy centers are tuned into resonance with each other by applying external electric fields. An extension of the present approach to generate entanglement of remote solid-state qubits is discussed.
CIT-5: a high-silica zeolite with 14-ring pores (1997)

The synthesis and structure of a new zeolite, CIT-5 (California Institute of Technology Number Five), is described, which possesses one-dimensional pores comprised of 14 T-atoms (tetrahedrally coordinated silicon or aluminium atoms).