gebhart/patrepeval huggingface dataset:
Continuous Smartphone Authentication using Wristbands (2019)

Many users find current smartphone authentication methods (PINs, swipe patterns) to be burdensome, leading them to weaken or disable the authentication. Although some phones support methods to ease the burden (such as fingerprint readers), these methods require active participation by the user and do not verify the user's identity after the phone is unlocked. We propose CSAW, a continuous smartphone authentication method that leverages wristbands to verify that the phone is in the hands of its owner. In CSAW, users wear a wristband (a smartwatch or a fitness band) with built-in motion sensors, and by comparing the wristband's motion with the phone's motion, CSAW continuously produces a score indicating its confidence that the person holding (and using) the phone is the person wearing the wristband. This score provides the foundation for a wide range of authentication decisions (e.g., unlocking phone, deauthentication, or limiting phone access). Through two user studies (N = 27, 11) we evaluated CSAW's accuracy, usability, and security. Our experimental evaluation demonstrates that CSAW was able to conduct initial authentication with over 99% accuracy and continuous authentication with over 96.5% accuracy.
Constrained Few-shot Class-incremental Learning (2022)

Continually learning new classes from fresh data without forgetting previous knowledge of old classes is a very challenging research problem. Moreover, it is imperative that such learning must respect certain memory and computational constraints such as (i) training samples are limited to only a few per class, (ii) the computational cost of learning a novel class remains constant, and (iii) the memory footprint of the model grows at most linearly with the number of classes observed. To meet the above constraints, we propose C-FSCIL, which is architecturally composed of a frozen meta-learned feature extractor, a trainable fixed-size fully connected layer, and a rewritable dynamically growing memory that stores as many vectors as the number of encountered classes. C-FSCIL provides three update modes that offer a trade-off between accuracy and compute-memory cost of learning novel classes. C-FSCIL exploits hyperdimensional embedding that allows to continually express many more classes than the fixed dimensions in the vector space, with minimal interference. The quality of class vector representations is further improved by aligning them quasi-orthogonally to each other by means of novel loss functions. Experiments on the CIFAR100, mini-ImageNet, and Omniglot datasets show that C-FSCIL outperforms the baselines with remarkable accuracy and compression. It also scales up to the largest problem size ever tried in this few-shot setting by learning 423 novel classes on top of 1200 base classes with less than 1.6% accuracy drop. Our code is available at https://github.com/IBM/constrained-FSCIL.
Allocation by conflict: a simple, effective multilateral cache management scheme (2002)

Several schemes have been proposed that incorporate an auxiliary buffer to improve the performance of a given size cache. Victim caching, aims to reduce the impact of conflict misses in direct-mapped caches. Victim offers competitive performance benefits, but requires a costly data path for swaps and saves between the main cache and the added buffer. Several multilateral schemes (e.g. NTS, PCS) offer competitive performance with Victim across a wide range of associativities, but require no swap/save data path. While these schemes perform well overall, their overall performance lags that of Victim when the main cache is direct-mapped. Furthermore, they also require costly hardware support, but in the form of history tables for maintaining allocation decision information. The paper introduces a multilateral cache management scheme, allocation by conflict (ABC), which generally outperforms Victim, NTS, and PCS. Furthermore, ABC has the lowest hardware requirements of any multilateral scheme-only a single additional bit per block in the main cache is required to maintain usage information for the allocation decision process, and no swap/save data path is needed.
An Adaptive Projected Subgradient Approach to Learning in Diffusion Networks (2009)

We present an algorithm that minimizes asymptotically a sequence of nonnegative convex functions over diffusion networks. In the proposed algorithm, at each iteration the nodes in the network have only partial information of the cost function, but they are able to achieve consensus on a possible minimizer asymptotically. To account for possible node failures, position changes, and/or reachability problems (because of moving obstacles, jammers, etc.), the algorithm can cope with changing network topologies and cost functions, a desirable feature in online algorithms where information arrives sequentially. Many projection-based algorithms can be straightforwardly extended to (probabilistic) diffusion networks with the proposed scheme. The system identification problem in distributed networks is given as one example of a possible application.
Split to win: near-optimal sensor network synthesis via path-greedy subproblems (2021)

As lightweight networked sensing and computing becomes pervasive in military operations, we are faced with the problem of quickly determining a maximally useful network topology for sensors subject to computation and communication constraints. In this paper, we frame network synthesis as a combinatorial optimization problem. Then, leveraging tools from submodular optimization, we develop a simple greedy algorithm that produces near-optimal sensor placements satisfying these communications and computation constraints.
Convective and absolute electrokinetic instability with conductivity gradients (2005)

Electrokinetic flow instabilities occur under high electric fields in the presence of electrical conductivity gradients. Such instabilities are a key factor limiting the robust performance of complex electrokinetic bio-analytical systems, but can also be exploited for rapid mixing and flow control for microscale devices. This paper reports a representative flow instability phenomenon studied using a microfluidic T-junction with a cross-section of 11 $\umu$ m by 155 $\umu$ m. In this system, aqueous electrolytes of 10:1 conductivity ratio were electrokinetically driven into a common mixing channel by a steady electric field. Convectively unstable waves were observed with a nominal threshold field of $0.5\,\hbox{kV}\,\hbox{cm}^{-1}$ , and upstream propagating waves were observed at $1.5\,\hbox{kV}\,\hbox{cm}^{-1}$ . A physical model has been developed for this instability which captures the coupling between electric and flow fields. A linear stability analysis was performed on the governing equations in the thin-layer limit, and Briggs–Bers criteria were applied to select physically unstable modes and determine the nature of instability. The model predicts both qualitative trends and quantitative features that agree very well with experimental data, and shows that conductivity gradients and their associated bulk charge accumulation are crucial for such instabilities. Comparison between theory and experiments suggests the convective role of electro-osmotic flow. Scaling analysis and numerical results show that the instability is governed by two key controlling parameters: the ratio of dynamic to dissipative forces which governs the onset of instability, and the ratio of electroviscous to electro-osmotic velocities which governs the convective versus absolute nature of instability.
Tolerance analysis and synthesis in assemblies (1999)

info:eu-repo/semantics/published
Lunar Dust Simulant Particle Adhesion on Copolyimide Alkyl Ethers (2020)

Mitigation of lunar dust contamination is one of the greatest challenges to be overcome to realize a sustained lunar presence. Likely solutions will integrate active mitigation strategies, requiring the input of external energy, and passive materials, exhibiting an intrinsic resistance to lunar dust adhesion. In this work, a series of copolyimide alkyl ethers containing per fluorinated side-chains were generated to evaluate the influence surface modification agents have on surface chemical, topographical, and mechanical properties. An expanded testing protocol to characterize the adhesion interaction between lunar dust simulant and the copolyimide substrate was carried out. The interfacial adhesion strength was in-situ measured by a custom-built particulate adhesion instrument, utilizing a sonic wand. Surface mechanical properties were characterized by nanoindentation, utilizing the continuous stiffness measurement approach. A nominal presence of surface modifying agents, 1 wt%, resulted in a six-fold reduction in adhesion strength of the interface. A strong inverse correlation between the adhesion strength and Young’s modulus of the substrate was identified. The reduction was attributed to a synergistic interaction between the surface energy, surface roughness, and modulus of the copolyimide alkyl ethers film.
Experimental demonstration of oxide-mode influence in a dual-purpose oxide-confined vertical-cavity surface-emitting laser/resonant detector (2002)

We report on design, fabrication, and characterization of a vertical-cavity surface-emitting laser (VCSEL) used as a resonant-cavity-enhanced detector for dual-purpose application. The geometry of this oxide-confined VCSEL takes advantage of the properties of the buried oxide layer to allow both single-mode laser emission and detection on a large surface. Here, we demonstrate the presence and the influence of oxide modes in the optical sensitivity spectrum of the device through spatially localized detection measurements. The wavelength of these modes has been correlated to the dip on the reflectivity spectrum measured at the same area of the device surface.
Optimal training signals for MIMO OFDM channel estimation (2005)

This work presents general classes of optimal training signals for estimation of frequency-selective channels in MIMO OFDM systems. Basic properties of the discrete Fourier transform are used to derive the optimal training signals which minimize the channel estimation mean square error. Both single and multiple OFDM training symbols are considered. Several optimal pilot tone allocations among the transmit antennas are presented and classified as frequency division multiplexing, time division multiplexing, code division multiplexing in frequency-domain, code division multiplexing in time-domain, and combinations thereof. All existing optimal training signals in the literature are special cases of the presented optimal training signals and our designs can be applied to pilot-only schemes as well as pilot-data multiplexed schemes.
Standardization Efforts for Traditional Data Center Infrastructure Management: The Big Picture (2020)

Traditional data center infrastructure suffers from a lack of standard and ubiquitous management solutions. Despite the achieved advances, existing tools lack interoperability and are sometimes hardware dependent. Vendors are already actively participating in the specification and design of new standard software and hardware interfaces within different forums. Nevertheless, the complexity and variety of data center infrastructure components that includes servers, cooling, networking, and power hardware, coupled with the introduction of the software defined data center paradigm, led to the parallel development of a myriad of standardization efforts. In an attempt to shed light on recent works, we survey and discuss the main standardization efforts for traditional data center infrastructure management.
Multi-channel electromyography-based mapping of spontaneous smiles (2020)

The herein described approach can be readily used for automated and objective mapping of facial expressions in general and in the assessment of normal and abnormal smiling in particular.
Comparison of Acoustoelastic Methods to Evaluate Stresses in Steel Plates and Bars (2002)

Most of the methods for determining residual stresses inside metallic solids are destructive, which is undesirable. The ultrasonic technique provides a useful nondestructive tool in the evaluation of stresses. This work presents the application of shear and longitudinal waves in the determination of stress state in a steel bar. A bar stressed by a hydraulic system is used to simulate the effect of the tensile stress. The stresses are recorded and compared with the real value calculated using the force and the bar cross-sectional area. The comparison between the theoretical and experimental results shows that it is possible to correlate tensile stresses and velocity with both methods, although the longitudinal critically refracted LCR waves have greater sensitivity to the stress.
Mutual Sliding Motion of Wrapped Filaments for Biomedical and Engineering Applications (2020)

Here we aim at understanding and modeling of macroscopic interactions and sliding motion of curved filaments during muscles' isometric action in which tension is developed without overall contraction. A generic dynamic model of a curved elastic filament undergoing sliding, twisting, and unraveling around a cylindrical filament affected by the interfilament friction force is developed in full detail. In particular, the dynamic equations describing the general sliding motion of a curved filament wrapped around a cylindrical filament and pulled by a constant force applied to a free end are derived and solved numerically; the other end of the curved filament is considered to be fixed at the cylindrical one. The model predicts propagation of an elastic wave over the wrapped filament determined by the filament stiffness and the interfilament friction. The wrapped filament deformation and its ultimate arrest are predicted, and the final configurations of such filaments are revealed. Accordingly, the wrapped filament strain is predicted as a function of time for different values of the friction coefficient. The potential applications and possible biomechanical links of the proposed generic model are also discussed.
Oncostatin M induces tyrosine phosphorylation in endothelial cells and activation of p62yes tyrosine kinase (1992)

Oncostatin M is a polypeptide cytokine produced by activated and transformed T lymphocytes that has diverse biologic effects, including growth inhibition of tumor cells and induction of IL-6 expression in cultured human endothelial cells (HEC). HEC are highly responsive to oncostatin M and express high levels of oncostatin M receptors relative to other cell types. Oncostatin M has previously been found to bind a specific receptor of 150 to 160 kDa. We have found through the use of anti-phosphotyrosine immunoblotting that oncostatin M induces tyrosine phosphorylation in HEC. Anti-phosphotyrosine antibodies specifically immunoprecipitated labeled oncostatin M cross-linked to its receptor, demonstrating that the oncostatin M receptor is either directly phosphorylated on tyrosine after ligand binding or is tightly associated with a phosphotyrosyl protein in these cells. The tyrosine kinase inhibitor herbimycin A blocked the induction of IL-6 by oncostatin M in HEC. In addition, immune complex kinase assays showed that oncostatin M markedly increased the activity of the p62yes tyrosine kinase with a small increase in p59fyn but no increase in p56lyn tyrosine kinase activity in HEC. We conclude that oncostatin M utilizes a tyrosine phosphorylation signal transduction pathway in HEC involving the activation of the p62yes tyrosine kinase, and that this tyrosine phosphorylation pathway leads to the induction of IL-6 expression.
34‐2: Invited Paper : Novel Four‐Transistor Pixel Circuit Using Source‐Follower Structure for Field‐Sequential‐Color Blue‐Phase Liquid Crystal Displays (2017)

We propose a novel pixel circuit using source‐follower structure to be independent of frequency effect of blue‐phase liquid crystal displays (BPLCDs). Simulation results indicated that required gray‐level‐voltages across the BPLC could be achieved accurately when a proper threshold voltage of the driving TFT was chosen. We also successfully fabricated a 12.7‐inch prototype BPLCD using the proposed pixel circuit driven with a field‐sequential‐color method of 240 Hz.
Abstract B27: Correlation between TNFα and LCL161 anti-tumor activity in patient derived xenograft models of human cancer (2009)

Abstract LCL161, a small molecule antagonist of inhibitor of apoptosis proteins (IAPs), induces TNF -mediated apoptosis in a subset of tumor cell lines including the MDA-MB-231 breast cancer line. To investigate the in vivo activity of LCL161, MDA-MB-231 tumor bearing mice were treated with a once weekly oral dose. We observed anti-tumor activity that was associated with pharmacodynamic responses including degradation of CIAP1 and induction of cleaved caspase 3. The loss of CIAP1, specifically the E3 ligase activity of this protein, has been shown to directly impact the stability of a number of client proteins including NIK (NF-κB inducing kinase), Mad1 (MAX-binding protein), and others. Gene expression analysis on LCL161 treated MDA-MB-231 tumors revealed a striking upregulation of NF-κB regulated target genes. These data were further supported by the observation that TNFα, a direct target of NF-κB, was induced in LCL161 treated MDAMB-231 tumor lysates. To explore whether TNFα expression levels could be used to predict single agent efficacy in a more clinically relevant context, a series of human primary tumor xenografts were profiled for baseline TNFα mRNA levels and evaluated for response to LCL161 in vivo. We observed that tumors with the highest TNFα expression levels showed the greatest sensitivity to LCL161. These studies demonstrate an essential role of the NF-κB pathway in IAP antagonist anti-tumor activity. Ongoing efforts focus on delineating the contribution of the canonical and non-canonical NF-κB pathways to efficacy and on leveraging this mechanism for LCL161 patient selection. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B27.
Empilement de cavités de Pérot-Fabry de taille réduite pour applications de type réseau focal (2009)

National audience
Microdispersive interfacial mixing in fast polymerizations (1988)

Abstract Interfacial activity between liquid reaction injection molding (RIM) reactants was observed using light microscopy. Diisocyanates were brought into contact with various diols and diamines in a thin (250 μm) gap. A dynamic phenomenon, rapidly producing a well‐mixed, intermaterial phase, was discovered. It was revealed that the rate of growth of this newly formed region was dependent on both the rate of reaction and the physical properties of the initially formed product species at the reaction interface. Spontaneous interfacial mixing also occurred without chemical reaction when a reaction product was dissolved in “capped” contacting reactant liquids. It is believed that strong interfacial intermolecular forces, inducing flow through the polymerization product layer formed immediately upon reactant contact, are responsible for the initial explosiveness of this microscopic process. The range of eventual thicknesses of the mixed, interfacial region (100–800 μm) for various typical RIM systems indicates that this microscopic subprocess may be significant to the fate of the overall process.
Resolving the Triexciton Recombination Pathway in CdSe/CdS Nanocrystals through State-Specific Correlation Measurements (2021)

As luminescence applications of colloidal semiconductor nanocrystals push toward higher excitation flux conditions, there is an increased need to both understand and potentially control emission from multiexciton states. We develop a spectrally resolved correlation method to study the triply excited state that enables direct measurements of the recombination pathway for the triexciton, rather than relying on indirect extraction of rates. We demonstrate that, for core-shell CdSe-CdS nanocrystals, triexciton emission arises exclusively from the band-edge S-like state. Time-dependent density functional theory and extended particle-in-a-sphere calculations demonstrate that reduced carrier overlap induced by the core-shell heterostructure can account for the lack of emission observed from the P-like state. These results provide a potential avenue for the control of nanocrystal luminescence, where core-shell heterostructures can be leveraged to control carrier separation and therefore maintain emission color purity over a broader range of excitation fluxes.
Porous Silicon as an Educational Vehicle for Introducing Nanotechnology and Interdisciplinary Materials Science (2000)

This paper describes why the authors view porous silicon (PSi) as an excellent vehicle for introducing university students to both basic and advanced materials science and engineering. Its ease of fabrication offers unique possibilities for university teachers to demonstrate nanoscale phenomena. Mechanical, physical, chemical and biological properties of PSi are amenable to laboratory tests employing a variety of modern but fairly standard characterization techniques. Its radically different behaviour from bulk silicon, but compatibility with VLSI technology, can be used to give students a taste of not only materials issues in electronics, but also optoelectronics, micro-optics, sensors, solar cells, micromachining, acoustics, medicine, biotechnology and even astrophysics! By way of an example, we analyze practical experience accumulated at the Technical University of Valencia during four years of teaching courses related with materials science. The introduction of PSi research into the curriculum has led to good synergy between theoretical aspects and practical studies, and has also improved personalization of studies where each student realizes their own nanostructure, and then has a choice of which material property and application area to delve into. Some prospects for future educational developments are then suggested.
Ring-Based Stiffening Flexure Applied as a Load Cell With High Resolution and Large Force Range (2017)

This paper applies linear elastic theory and Castigliano's first theorem to design nonlinear (stiffening) flexures used as load cells with both large force range and large resolution. Low stiffness at small forces causes high sensitivity, while high stiffness at large forces prevents over-straining. With a standard 0.1 μm deflection sensor, the nonlinear load cell may detect 1% changes in force over five orders of force magnitude. In comparison, a traditional linear load cell functions over only three orders of magnitude. We physically implement the nonlinear flexure as a ring that increasingly contacts rigid surfaces with carefully chosen curvatures as more force is applied. We analytically describe the load cell performance as a function of its geometry. We describe methods for manufacturing the flexure from a monolithic part or multiple parts. We experimentally verify the theory for two load cells with different parameters.