Online handwriting recognition: the NPen++ recognizer

This paper presents the online handwriting recognition system NPen++ developed at the University of Karlsruhe and Carnegie Mellon University. The NPen++ recognition engine is based on a multi-state time delay neural network and yields recognition rates from 96% for a 5,000 word dictionary to 93.4% on a 20,000 word dictionary and 91.2% for a 50,000 word dictionary. The proposed tree search and pruning technique reduces the search space considerably without losing too much recognition performance compared to an exhaustive search. This enables the NPen++ recognizer to be run in real-time with large dictionaries. Initial recognition rates for whole sentences are promising and show that the MS-TDNN architecture is suited to recognizing handwritten data ranging from single characters to whole sentences. Received September 3, 2000 / Revised October 9, 2000     

Toward the improvement of image-guided interventions for minimally invasive surgery: three factors that affect performance

OBJECTIVES: The objectives were to measure the impact of specific features of imaging devices on tasks relevant to minimally invasive surgery (MIS) and to investigate cognitive and perceptual factors in such tasks. BACKGROUND: Although image-guided interventions used in MIS provide benefits for patients, they pose drawbacks for surgeons, including degraded depth perception and reduced field of view (FOV). It is important to identify design factors that affect performance. METHOD: In two navigation experiments, observers fed a borescope through an object until it reached a target. Task completion time and object shape judgments were measured. In a motion perception experiment, observers reported the direction of a line that moved behind an aperture. A motion illusion associated with reduced FOV was measured. RESULTS: Navigation through an object was faster when a preview of the object's exterior was provided. Judgments about the object's shape were more accurate with a preview (compared with none) and with active viewing (compared with passive viewing). The motion illusion decreased with a rectangular or rotating octagonal viewing aperture (compared with circular). CONCLUSIONS: Navigation performance may be enhanced when surgeons develop a mental model of the surgical environment, when surgeons (rather than assistants) control the camera, and when the shape of the image is designed to reduce visual illusions. APPLICATION: Unintentional contact between surgical tools and healthy tissues may be reduced during MIS when (a) visual aids permit surgeons to maintain a mental model of the surgical environment, (b) images are bound by noncircular apertures, and (c) surgeons manually control the camera.     

An entropic characterization of protein interaction networks and cellular robustness.

The structure of molecular networks is believed to determine important aspects of their cellular function, such as the organismal resilience against random perturbations. Ultimately, however, cellular behaviour is determined by the dynamical processes, which are constrained by network topology. The present work is based on a fundamental relation from dynamical systems theory, which states that the macroscopic resilience of a steady state is correlated with the uncertainty in the underlying microscopic processes, a property that can be measured by entropy. Here, we use recent network data from large-scale protein interaction screens to characterize the diversity of possible pathways in terms of network entropy. This measure has its origin in statistical mechanics and amounts to a global characterization of both structural and dynamical resilience in terms of microscopic elements. We demonstrate how this approach can be used to rank network elements according to their contribution to network entropy and also investigate how this suggested ranking reflects on the functional data provided by gene knockouts and RNAi experiments in yeast and Caenorhabditis elegans. Our analysis shows that knockouts of proteins with large contribution to network entropy are preferentially lethal. This observation is robust with respect to several possible errors and biases in the experimental data. It underscores the significance of entropy as a fundamental invariant of the dynamical system, and as a measure of structural and dynamical properties of networks. Our analytical approach goes beyond the phenomenological studies of cellular robustness based on local network observables, such as connectivity. One of its principal achievements is to provide a rationale to study proxies of cellular resilience and rank proteins according to their importance within the global network context.     

FPGA Implementation of Cross Virtual Concatenation Transmitter/ Receiver for Data Transmission over Next Generation SDH Systems

Cross Virtual Concatenation is the new technique proposed for bandwidth efficient transmission of data over SDH networks. SDH networks came into existence for reliable voice transmission. As the demand of data traffic grew in wide area networks, new technologies were developed and standardized for data transmission over SDH networks. The technologies used namely, GFP (generic framing procedure), VCAT (virtual concatenation) and LCAS (link capacity adjustment scheme) enable network operator to provide integrated voice and data services over their legacy SDH infrastructure. Data packets are encapsulated using framing protocols GFP. VCAT is a process of distributing the GFP framed data payload in number of virtual channels of same capacity forming a Virtually Concatenated Group (VCG). LCAS is used for dynamic bandwidth allocation. LCAS enhances the VCAT scheme with hitless in service addition and removal of VC’s to/from the VCG.VCAT combines homogeneous virtual channels together which in some cases limits the performance of VCAT. This paper describes the implementation of new concatenation technology named cross virtual concatenation (CVC), which combines heterogeneous VC’s together to utilize the SDH bandwidth more efficiently. CVC implementation requires only end node equipments to be upgraded as VCG members travel through the link similar to the conventional VCAT. This paper proposes FPGA implementation of transmitter and receiver circuits for 100 Mbps Ethernet data transmission over next Generation SDH systems using CVC, where two types of VC’s namely VC-3 and VC-12 are used for data transmission. Total Transmission delay is calculated as 125 μs. There is no complexity added at the receiver side due to this delay. The receiver is designed for 32 ms differential delay compensation which can be increased up to maximum 256 ms by increasing the buffer size at the receiver.     

Effect of Fiber Length on Carbon Nanotube-Induced Fibrogenesis

Given their extremely small size and light weight, carbon nanotubes (CNTs) can be readily inhaled by human lungs resulting in increased rates of pulmonary disorders, particularly fibrosis. Although the fibrogenic potential of CNTs is well established, there is a lack of consensus regarding the contribution of physicochemical attributes of CNTs on the underlying fibrotic outcome. We designed an experimentally validated in vitro fibroblast culture model aimed at investigating the effect of fiber length on single-walled CNT (SWCNT)-induced pulmonary fibrosis. The fibrogenic response to short and long SWCNTs was assessed via oxidative stress generation, collagen expression and transforming growth factor-beta (TGF-β) production as potential fibrosis biomarkers. Long SWCNTs were significantly more potent than short SWCNTs in terms of reactive oxygen species (ROS) response, collagen production and TGF-β release. Furthermore, our finding on the length-dependent in vitro fibrogenic response was validated by the in vivo lung fibrosis outcome, thus supporting the predictive value of the in vitro model. Our results also demonstrated the key role of ROS in SWCNT-induced collagen expression and TGF-β activation, indicating the potential mechanisms of length-dependent SWCNT-induced fibrosis. Together, our study provides new evidence for the role of fiber length in SWCNT-induced lung fibrosis and offers a rapid cell-based assay for fibrogenicity testing of nanomaterials with the ability to predict pulmonary fibrogenic response in vivo.     

Advances in neutron imaging

Imaging techniques based on neutron beams are rapidly developing and have become versatile non-destructive analyzing tools in many research fields. Due to their intrinsic properties, neutrons differ strongly from electrons, protons or X-rays in terms of their interaction with matter: they penetrate deeply into most common metallic materials while they have a high sensitivity to light elements such as hydrogen, hydrogenous substances, or lithium. This makes neutrons perfectly suited probes for research on materials that are used for energy storage and conversion, e.g., batteries, hydrogen storage, fuel cells, etc. Moreover, their wave properties can be exploited to perform diffraction, phase-contrast and dark-field imaging experiments. Their magnetic moment allows for resolving magnetic properties in bulk samples. This review will focus on recent applications of neutron imaging techniques in both materials research and fundamental science illustrated by examples selected from different areas.     

Influence of Electric Poling on Pb0.9Bi0.1Fe0.55Nb0.45O3 Multiferroic

This paper analyzes the influence of electric poling on structure, magnetism, and ferroelectricity by temperature-dependent Raman scattering (180 K–500 K), magnetic susceptibility, and ferroelectric measurements on Pb_0.9Bi_0.1Fe_0.55Nb_0.45O₃ (PBFNO) multiferroic. X-ray diffraction (XRD) has confirmed the monoclinic structure for PBFNO sample before and after poling. Rietveld refined XRD for poled and unpoled sample shows the influence of electric poling on Fe-O1, Fe-O2, Nb–O, and Bi-O modes with small variation in the lattice parameters. The unpoled PBFNO exhibits broad and overlapping 10 active modes at room temperature (100 to 1300 cm^?1) at 147, 212, 255, 431, 479, 561, 700, 795, 835, and 1112 cm^?1. In case of a poled sample, Pb–O and Nb–O-Nb modes become more active compared to the unpoled sample. Changes observed in the temperature-dependent magnetic measurements, i.e., ZFC/FC and M-H loop, evidence the poling effects on Fe–O and Nb–O active modes. By poling the improvement in ferroelectric domain, ordering occurs, and it is confirmed by P-E loops. The consequences of numerous investigations on electric poling of PBFNO will provide the foundation for future device development and design.

     

Improved mechanical and moisture resistance property of in situ polymerized transparent PMMA/Cellulose composites

This article evaluates the role of cellulosic fillers in a synthetic polymer matrix like polymethylmethacrylate (PMMA) when incorporated by in situ suspension polymerization technique. Cellulose micro/nanofibers (CNF) were extracted from jute fibers and chemically modified with maleic anhydride (MACNF) to increase their interfacial compatibility with PMMA by participation of the MA moiety in the free radical polymerization with MMA. The effect of incorporating MACNF on the physical and mechanical properties of the PMMA matrix was investigated. Optical transparency was retained in the in situ prepared PMMA/cellulose composites (IPMC) similar to that of unreinforced PMMA. Another set of PMMA/cellulose composites was prepared by dispersing MACNF in PMMA matrix by ex situ solution dispersion method (EPMC). The modification of CNF with MA significantly improved the filler/matrix interfacial compatibility and in situ polymerization technique further enhanced the properties of the composites. The high moisture absorption tendency, which is a major drawback of the cellulose filled composites, remarkably reduced in IPMC. POLYM. COMPOS., 36:1748–1758, 2015. © 2014 Society of Plastics Engineers     

Computational design of thermoset nanocomposite coatings: Methodological study on coating development and testing

Thermoset nanocomposites (TSNCs) may offer significantly improved performance over conventional thermoset materials, and thus are attractive for wide industrial applications, especially in the coating industry. Design of TSNCs via experiment, however, faces various technical challenges due to design complexity. Computational design can provide deep insights and identify superior design solutions through exploring opportunities in a usually huge design space. This paper introduces a generic computational methodology for the design, characterization, and testing of TSNC-based coatings. A distinct feature of the methodology is its capability of generating quantitative correlations among material formulation, processing condition, coating microstructure and property, coating performance, and processing efficiency. The correlations can enable a comprehensive analysis for optimal TSNC coating design. Case studies will demonstrate the methodological efficacy and attractiveness.     

Spinel-Coated Graphite for Carbon Containing Refractory Castables

Oxidation resistance and water wettability of graphite flakes have been improved by a thin sol–gel film of magnesium aluminate spinel (MgAl₂O₄) over its surface. The hydrosol has been synthesized by less expensive precursors and the spinel formation has been studied by scanning electron microscopy (SEM), supplemented with energy dispersive spectral analysis. After an easy-to-use mixing procedure, drying (110°C), and subsequent calcination (550°C), coated graphites were sieved to below 75 μm. The coating over the powder contained 1.5 wt% MgAl₂O₄, which enormously increased the oxidation resistance (performed at 600°, 900°, and 1200°C) and water wettability, as revealed by hydrophilic functional groups from infrared spectra. Defective, intermediate spinel structure of fine, lamellar Mg-doped γ-Al₂O₃ has been considered to be significant for this improvement. An approximate (1:2) stoichiometry of (Mg:Al) in the coating composition was confirmed by an X-ray photoelectron spectroscopy test. Castables prepared by this graphite remarkably improved their bulk density and apparent porosity compared with those prepared by the as-received graphite. Casting water was reduced along with the amount of antioxidants. This also enhanced the resistance toward the basic slag by retaining the graphite in the refractory.