gebhart/patrepeval huggingface dataset:
Controlled Inter-Carrier Interference for Physical Layer Security in OFDM Systems (2016)

Performance of OFDM is known to be very sensitive to frequency synchronization errors. By exploiting this feature, a novel technique is proposed to provide secure communication against eavesdropping. The technique is based on introducing self inter-carrier interference to pre-compensate the carrier offset only for the legitimate user. This pre-compensation process depends on both the channel and the local carrier offset of the legitimate user, hence provides another degree of freedom for secrecy. Since an eavesdropper experiences an uncorrelated channel, his performance is expected to be degraded. Also our approach converts the simple one-tap frequency domain channel equalization to a very complex receiver operation for the eavesdropper. Moreover, the power aspects of this technique are discussed. By setting a threshold in the pre-compensation stage, we provide an acceptable trade-off between the transmitted power and the error performance.
Chemical and Physical Characterization of a Novel Poly(Carbonate Urea) Urethane Surface with Protein Crosslinker Sites (1997)

A major complication which occurs with implantable polyurethane biomaterials is bioincompatibility between blood and the biomaterial surface. Development of a novel biodurable polyurethane surface to which biological agents, such as growth factors or anticoagulants could be covalently bound, would be beneficial. The purpose of this study was to synthesize a novel poly(carbonate urea) urethane polymer with carboxylic acid groups which would serve as "anchor" sites for protein attachment. Physical characteristics such as tensile strength, initial modulus, ultimate elongation, tear strength, water/alcohol uptake and water vapor permeation were then evaluated and compared to other biomedical-grade polyurethanes. Covalent linkage of the blood protein albumin to this novel surface was then examined. A biodurable polycarbonate-based polyurethane containing carboxylic acid groups (cPU) was synthesized using a two step procedure incorporating the chain extender 2,2-bis(hydroxymethyl)-propionic acid (DHMPA). Tensile strength of this cPU film was 2.7 and 2.6 fold greater than both a polycarbonate-based polyurethane synthesized with a 1,4-butanediol chain extender (bdPU) and Mitrathane (Mit) controls, respectively. The cPU polymer also possessed 7.8 and 31 fold greater structural rigidity upon evaluation of initial modulus as compared to the bdPU and Mit, respectively. Ultimate elongation for the bdPU films was slightly higher than the cPU and Mit films, which had comparable elongation properties. The force required to tear the bdPU film was 1.9 and 32 fold greater than the cPU and Mit films, respectively. Alcohol solution uptake by all of the polyurethane segments increased with increasing alcohol concentrations, with the cPU having the greatest uptake. Water uptake was minimal for all the polyurethanes examined and was not affected by altering pH. Water vapor permeation was lowest for the cPU films as compared to both bdPU and Mit. Swelling the cPU in 50% ethanol prior to evaluation slightly increased water vapor permeation through the films. Covalent linkage of the radiolabelled blood protein albumin (125I-BSA) to the cPU segments incubated with the heterobifunctional crosslinker 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) was greatest in the higher percent of ethanol as compared to controls. These results serve as foundation for developing a novel poly(carbonate urea) urethane with physical characteristics comparable to other medical-grade polyurethanes while having protein binding capabilities.
Temporal characterization of CMOS circuits by time resolved emission microscopy (2002)

Directly measures the temporal behavior of fast circuits built from silicon CMOS devices using the hot electron light emission which occurs during switching. The optical technique measures the switching of individual devices separated by as little as 0.5-1.0 micron, with extension to 0.17 micron spacings possible. Temporal resolution is currently 50 psec and improvement to 20 psec is expected. The technique involves no external probes or fabrication of any special test circuits. It simultaneously measures switching waveforms on thousands of devices, giving it a unique ability to efficiently survey large arrays of devices.
A General MRI-CEST Ratiometric Approach for pH Imaging: Demonstration of<i>in Vivo</i>pH Mapping with Iobitridol (2014)

Chemical exchange saturation transfer (CEST) is a novel contrast mechanism for magnetic resonance imaging (MRI). CEST MRI selectively saturates exchangeable protons that are transferred to MRI-detectable bulk water signal. MRI-CEST (pH)-responsive agents are probes able to map pH in the microenvironment in which they distribute. To minimize the confounding effects of contrast agent concentration, researchers have developed ratiometric CEST imaging, which investigates contrast agents containing multiple magnetically non-equivalent proton groups, whose prototropic exchange have different pH responses. However, conventional ratiometric CEST MRI imposes stringent requirements on the selection of CEST contrasts agents. In this study, a novel ratiometric pH MRI method based on the analysis of CEST effects under different radio frequency irradiation power levels was developed. The proposed method has been demonstrated using iobitridol, an X-ray contrast agent analog of iopamidol but containing a single set of amide protons, both in vitro and in vivo.
Expression of mouse mammary tumor virus-like env gene sequences in human breast cancer. (1998)

We have reported previously (Wang et al, Cancer Res., 55: 5173-5179, 1995) the presence of a 660-bp sequence that is 90-98% homologous to the env gene of mouse mammary tumor virus in 38% of 314 unselected breast cancer samples, in some breast cancer cell lines, and in 1.8% of the 107 normal breast specimens from reduction mammoplasties. In this communication, we have investigated whether the 660-bp sequence or a smaller 256-bp sequence within the 660 bp were expressed in breast tumors, normal breasts, and breast cancer cell lines by means of reverse transcription-PCR. The results indicated that expression of the 660-bp sequence was detected in 66% of the sequence-positive breast tumors studied and in none of the negative tumors or normal breasts and that the 256-bp sequence was expressed in all of the env-positive breast cancer cell lines tested. Sequence analysis revealed that the expressed 660-bp sequence is 98% homologous to the env gene of mouse mammary tumor virus with only one small stretch of 46 bp homologous to endogenous viral sequences. The presence and expression of this sequence is related to a group of human breast cancers in which the concept of a retroviral etiology can be entertained.
A control-theoretic system identification framework and a real-time closed-loop clinical simulation testbed for electrical brain stimulation (2018)

The system identification framework with the new BN-modulated waveform and the clinical HIL simulation testbed can help develop future model-based closed-loop electrical brain stimulation systems for treatment of neurological and neuropsychiatric disorders.
Batch-normalized recurrent highway networks (2017)

Gradient control plays an important role in feed-forward networks applied to various computer vision tasks. Previous work has shown that Recurrent Highway Networks minimize the problem of vanishing or exploding gradients. They achieve this by setting the eigenvalues of the temporal Jacobian to 1 across the time steps. In this work, batch normalized recurrent highway networks are proposed to control the gradient flow in an improved way for network convergence. Specifically, the introduced model can be formed by batch normalizing the inputs at each recurrence loop. The proposed model is tested on an image captioning task using MSCOCO dataset. Experimental results indicate that the batch normalized recurrent highway networks converge faster and performs better compared with the traditional LSTM and RHN based models.
Unsupervised Control Through Non-Parametric Discriminative Rewards (2018)

Learning to control an environment without hand-crafted rewards or expert data remains challenging and is at the frontier of reinforcement learning research. We present an unsupervised learning algorithm to train agents to achieve perceptually-specified goals using only a stream of observations and actions. Our agent simultaneously learns a goal-conditioned policy and a goal achievement reward function that measures how similar a state is to the goal state. This dual optimization leads to a co-operative game, giving rise to a learned reward function that reflects similarity in controllable aspects of the environment instead of distance in the space of observations. We demonstrate the efficacy of our agent to learn, in an unsupervised manner, to reach a diverse set of goals on three domains -- Atari, the DeepMind Control Suite and DeepMind Lab.
MEMs-based modular phased array for low earth orbiting satellite terminals (2004)

This paper describes a concept for a single-beam phased array for a low earth orbiting (LEO) satellite terminal. The phased array is made of a number of sub-array modules that constitute the building blocks in the array. The individual module is a highly integrated multilayer structure that contains the radiating elements, the phase shifters, polarizer circuit, and power divider/combiner circuits. The module uses micro-electro-mechanical system (MEMS) technology. The layers in the sub-array module are built with emphasis on integration techniques and choice of material. One option is to use a low temperature co-fired ceramic (LTCC) material that has been proven to have several desirable features as a substrate in microwave applications. These features include low-cost, low-loss, mechanical stability and ease of stacking or vertical integration of printed circuit layers. The sub-array modules are fed by a power dividing network for the transmit array or a power combining network for the receive array.
Emerging technology for the reduction of sulfur in FCC fuels (1993)

Passage of the Clean Air Act of 1990 and new regulations issued in California will set new limits on the sulfur content of gasoline. Because most of the sulfur in the gasoline pool comes from FCC naphtha, there is a strong incentive to reduce the sulfur content of this stream in the most cost efficient manner. This work introduces emerging catalytic technology for the direct reduction of the sulfur content of FCC gasolines, called the GSR[trademark] (Gasoline Sulfur Reduction) technology. Studies of this new technology were carried out using the Davison Circulating Riser pilot unit. The GSR technology is shown to reduce the sulfur in FCC naphtha by 15%, with two feedstocks. It is shown that this technology is selective to sulfur species in the middle of the gasoline boiling range, and converts these species to H[sub 2]S, while preserving most of the base catalyst selectivities. Various other catalytic scenarios for minimizing the gasoline sulfur content are also given.
Regulation of a human epidermal keratin gene: sequences and nuclear factors involved in keratinocyte-specific transcription. (1990)

The keratinocyte is a major cell type of the body, and in epidermis, keratinocytes have potential for future gene targeting and drug therapy. Despite the importance of keratinocytes in cell biology and medicine, little is known about the molecular mechanisms underlying keratinocyte-specific gene expression. Here, we report the first detailed characterization of the sequences and factors controlling expression of a human gene expressed specifically in keratinocytes. Using 5' upstream sequence of the human K14 keratin gene coupled to one of two reporter genes, we examined sequences necessary and sufficient for expression of K14 in both cultured human keratinocytes and in mitotically active basal keratinocytes of transgenic mouse epidermis. We demonstrated the existence of distal and proximal elements located 5' from the transcription initiation site of the hK14 gene, which when combined with a TATA box element, appear to act in concert to drive keratinocyte-specific expression. We examined the proximal region in detail. After using CAT assays to narrow a transcriptional activation element to within 110 bp, we demonstrated the existence of a keratinocyte nuclear factor which binds to a 10-bp palindrome, 5'-GCCTGCAGGC-3', within this domain. Using methylation interference analysis, we identified the G residues important for factor binding, and showed that point mutations in these G residues not only blocked factor binding but also resulted in decreased transcriptional activity of an hK14-CAT gene. The factor was most abundant in keratinocytes, was expressed at lower levels in some simple epithelial cell lines, and was not detected in fibroblasts or lymphoma cells. Moreover, the 10-bp sequence was similar to sequences found in the 5' upstream sequences of several other genes expressed in keratinocytes, and at least one of these genes, the human K1 gene, contained a sequence that competed with the hK14 proximal element for binding factor. Collectively, our data suggest that both the sequence and the nuclear factor that we have identified may be involved in controlling keratinocyte-specific expression in vitro and in vivo.
Imaging through distributed-volume aberrations using single-shot digital holography (2018)

This paper explores the use of single-shot digital holography data and a novel algorithm, referred to as multiplane iterative reconstruction (MIR), for imaging through distributed-volume aberrations. Such aberrations result in a linear, shift-varying or "anisoplanatic" physical process, where multiple-look angles give rise to different point spread functions within the field of view of the imaging system. The MIR algorithm jointly computes the maximum a posteriori estimates of the anisoplanatic phase errors and the speckle-free object reflectance from the single-shot digital holography data. Using both simulations and experiments, we show that the MIR algorithm outperforms the leading multiplane image-sharpening algorithm over a wide range of anisoplanatic conditions.
Efficient Cell-Specific Beamforming for Large Antenna Arrays (2021)

We propose an efficient method for designing broad beams with spatially flat array factor and efficient power utilization for cell-specific coverage in communication systems equipped with large antenna arrays. To ensure full power efficiency, the method is restricted to phase-only weight manipulations. Our framework is based on the discovered connection between dual-polarized beamforming and polyphase Golay sequences. Exploiting this connection, we propose several methods for array expansion from smaller to larger sizes, while preserving the radiation pattern. In addition, to fill the gaps in the feasible array sizes, we introduce the concept of $ε$-complementarity that relaxes the requirement on zero side lobes of the sum aperiodic autocorrelation function of a sequence pair. Furthermore, we develop a modified Great Deluge algorithm (MGDA) that finds $ε$-complementary pairs of arbitrary length, and hence enables broad beamforming for arbitrarily-sized uniform linear arrays. We also discuss the extension of this approach to two-dimensional uniform rectangular arrays. Our numerical results demonstrate the superiority of the proposed approach with respect to existing beam-broadening methods.
High-average-power, long-pulse-length solid-state illuminator laser for high-resolution imaging (1996)

Summary form only given. We have recently reported a laser amplification technique that allows pulses of up to 1 /spl mu/s in duration to be efficiently generated from a master oscillator power amplifier (MOPA) geometry. The incorporation of very low threshold SBS phase conjugation using Brillouin-enhanced four wave mixing provides near-diffraction limited divergence and the output pulses can be frequency-doubled to 527 nm with >50% total external conversion efficiency. We have applied this technology to a high-average-power laser system designed as an illuminator for high-resolution speckle imaging (HRI) of distant objects through the turbulent atmosphere. The laser incorporates four flash lamp pumped Nd:glass zig-zag laser amplifers.
1 Multi-User Scheduling in the 3GPP LTE Cellular Uplink (2013)

Abstract—We consider resource allocation in the 3GPP Long Term Evolution (LTE) cellular uplink, which will be the most widely deployed next generation cellular uplink. The key features of the 3GPP LTE uplink (UL) are that it is based on a modified form of the orthogonal frequency division multiplexing based multiple acess (OFDMA), which enables channel dependent frequency selective scheduling, and that it allows for multi-user (MU) scheduling wherein multiple users can be assigned the same time-frequency resource. In addition to the considerable spectral efficiency improvements that are possible by exploiting these two features, the LTE UL allows for transmit antenna selection together with the possibility of employing advanced receivers at the base-station, which promise further gains. However, several practical constraints that seek to maintain a low signaling overhead, are also imposed. In this paper, we show that the resulting resource allocation problem is APX-hard and then propose a local ratio test (LRT) based constant-factor deterministic polynomial-time approximation algorithm which can accommodate all the practical constraints. Detailed evaluations reveal that the proposed algorithm together with its proposed enhancements offers significant gains. I.
The temperature dependence of key electro-optical characteristics for mid-infrared emitting quantum cascade lasers (2011)

The equations for the threshold-current density J<sub>th</sub>, differential quantum efficiency η<sub>d</sub> and maximum wallplug efficiency η<sub>wp,max</sub> for quantum-cascade lasers (QCLs) have been modified for electron leakage and backfilling. We used a thermalexcitation model of "hot" injected electrons from the upper laser state to upper active-region energy states to calculate leakage currents. Then the calculated characteristic temperature T<sub>0</sub> for J<sub>th</sub> was found to agree well with experiment for both conventional and deep-well QCLs. The characteristic temperature T<sub>1</sub> for η<sub>d</sub> was deduced to be due to both electron leakage and an increase in the waveguide-loss coefficient. For conventional mid-infrared QCLs η<sub>wp,max</sub> is found to be strongly temperature dependent which explains experimental data. By using a new concept: tapered active-region (TA), deep-well QCLs have been optimized for virtual suppression of the electron-leakage currents. In turn, at room temperature, for continuous-wave (CW)-operating, 4.5-5.0 μm-emitting TA QCLs we estimate the threshold current to decrease by ~ 25 %, the active-region temperature rise at the η<sub>wp,max</sub> point to decrease by ~ 30 %, and the single-ended, η<sub>wp,max</sub> value to become at least 22 %. Preliminary results from TA QCLs include T1 values as high as 454 K, over the 20-60 oC heatsink-temperature range.
A Novel Fiber Optic Tactile Array Sensor (1987)

A new robotic tactile sensor based on fiber optics is described. The sensor array is based on a matrix of optical fibers in perpendicular rows and columns separated by an elastomeric pad. The elastomer provides compliant response to normal force applied to the structure, and the magnitude of the force is measured by a change in transmitted light coupling across a gap between the fibers. Spatial structure of the force applied to the pad is obtained by the matrix addressing of rows of fibers individually excited by light emitting diodes (LEDs) and orthogonally arranged columns of signal pickup fibers conducting the sensed light to photodetectors. The structure can be made thin enough to wrap conformally over a curved surface. The sensor array lends itself to sensing and control applications in robotic end effectors and as a tactile imaging platform for part identification and orientation to complement or replace optical vision systems.
V(D)J Recombination and DNA Double-Strand-Break Repair (2004)

The vertebrate immune system encounters an almost limitless number and variety of foreign antigens. Innate immunity provides the first line of defense against infection. Adaptive immune responses also play a crucial role in defense against pathogens and depend on the generation of a vast repertoire of soluble and membrane-bound antigen receptors expressed on B- and T-lymphocytes respectively. The variable regions of the Immunoglobulin (Ig) and the T-cell receptor (TCR) are encoded by a modest number of gene segments. Immunological diversity is achieved through a series of programmed DNA rearrangements, termed V(D)J recombination, the only known form of site-specific DNA rearrangement in vertebrates. This assembly process is highly conserved throughout evolution and present in most of the vertebrates analyzed so far.
Prospects for x-ray holography with free-electron lasers (1990)

We review the technical advantages offered by x-ray holographic microscopy for imaging the structure of living biological specimens. We discuss the wavelength, coherence, energy, and pulse-length requirements and conclude that these could be met by free-electron laser architectures of the near future. We also show that Fourier-transform holography using a reference scattering sphere is the best optical configuration for a practical instrument.
Resonant cavity mode enabled wireless power transfer (2014)

This letter proposes using the electromagnetic resonant modes of a hollow metallic structure to provide wireless power to small receivers contained anywhere inside. The coupling between a large chamber (used as a cavity resonator) and a small wire loop (used as a receiver) is studied. An analytic expression for the coupling coefficient between the fields in the cavity and a loop receiver is derived. This model is validated against simulation and experimental results. Finally, wireless power transfer is demonstrated at an efficiency of over 60% for large volumes in the structure, even though the receiver is a small 7.6 cm square shaped loop and the distance to the source probe is greater than 1 m. This technique for wireless power transfer has thus far been unexplored, and the results here serve as a starting point for resonant cavity mode wireless power systems with many receivers having arbitrary locations and orientations.
Cyclization of pyrrhocoricin retains structural elements crucial for the antimicrobial activity of the native peptide (2004)

Pyrrhocoricin is a naturally occurring antimicrobial peptide from the European fire bug Pyrrhocoris apterus. It has submicromolar activity against a range of Gram-negative bacterial strains and has created recent interest as a lead for the development of novel antibiotic compounds. In this study, we have used NMR spectroscopy to determine the solution structures of pyrrhocoricin and a synthetic macrocyclic derivative that has improved in vivo pharmaceutical properties. Native pyrrhocoricin is largely disordered in solution, but there is evidence of a subpopulation with ordered turn regions over residues 2-5, 4-7, and 16-19. The macrocyclic derivative incorporates a nine amino acid linker joining the N- and C-termini, which does not adversely affect the antimicrobial potency but leads to a broader spectrum of activity. The NMR data suggest that the turn conformations in the cyclic derivative are similar to those in the native form, thus implicating them in the biological function.