Accurate Gate Impedance Determination on Ultraleaky MOSFETs by Fitting to a Three-Lumped-Parameter Model atFrequencies From DC to RF

We present an experimental methodology that demonstrates the suitability of the conventional three-lumped- parameter model for gate impedance of MOSFET devices at frequencies from dc to the gigahertz range, which permits accurate extraction of model parameters. The parasitic effects at a high frequency are minimized by using radio frequency techniques (i.e., short return paths and de-embedding structures), whereas a robust parameter extraction algorithm overcomes possible instrument inaccuracies. When combined, these allow simultaneous extraction of all three parameters (i.e., C_gate, R_DT and R_series) from the model. The technique is applied to conventional SiO₂ -based MOSFET devices and to ultraleaky HfO₂ devices with aggressively scaled gate dielectric thickness.     

Inverting a forest canopy reflectance model to retrieve the overstorey and understorey leaf area index for forest stands

In this article, the Kuusk–Nilson forest reflectance and transmittance (FRT) model was inverted to retrieve the overstorey and understorey leaf area index (OU-LAI) of forest stands in the Longmenhe forest nature reserve in China. Data from detailed sample sites were collected in 30 forest stands representing the typical vegetation community in the study area. An uncertainty and sensitivity matrix (USM) was used to analyse the sensitivity of the FRT model parameters based on these data. The results indicated that overstorey LAI strongly influenced stand reflectance, whereas understorey LAI had a much lower impact. To predict OU-LAI in forest stands, FRT model inversion is carried out by minimizing a merit function that provides a measure of the difference between the reflectance simulated by the FRT model and the reflectance originating from optimal band selection of Hyperion data. Various combinations of Hyperion bands were tested to evaluate the most effective wavelengths for the inversion of OU-LAI. The best estimates from 17 Hyperion bands (5 VIS, 8 NIR, 4 SWIR) by the FRT model inversion showed an R ²?=?0.41 and RMSE/mean?=?0.21 for overstorey LAI and R ²?=?0.49 and RMSE/mean?=?0.91 for understorey LAI. Advantages and disadvantages of FRT inversion for retrieval OU-LAI combined with Hyperion data are discussed.     

Digital Surface of Revolution with Hand-Drawn Generatrix

In this paper we present a simple method to create general 3D digital surfaces of revolution based on a 2D implicit curve of revolution (therefore not limited to a circle) and a hand-drawn generatrix. Our method can handle any sequence of Euclidean 2D points, which represents a curve, as generatrix. One can choose the topology of the surface that may have 1-tunnels, 0-tunnels or no tunnels with applications in 3D printing for instance. An online tool that illustrates the method is proposed.     

Color tracking with contextual switching: real-time implementation on CPU

Journal of Real-Time Image Processing - The paper proposes contributions for mean-shift (MS) and covariance tracking (CT), and makes these two complementary methods cooperate. While MS runs fast...     

Fire Department Attended and Unattended Fires: Estimates from the 2004–2005 National Sample Survey and Comparison with Previous Surveys

Previous national surveys in 1974 and 1984 have shown that although attended and unattended fires differed substantially in severity and fire losses, there were between 10 and 29 unwanted residential fires for every fire reported to, or attended by, U.S. fire departments. The study objective was to obtain new estimates of fires not attended by fire departments. Interest in unattended fires derives from the understanding that most fires begin small, then unless controlled, grow until fire department assistance is needed. To update these analyses, a national telephone survey was conducted during 2004 and 2005. The survey had 916 respondents who reported one or more residential fires during the previous 90-day period. The principal methodological issues in analyzing the survey data included: (1) determining the optimum recall period to balance sampling variance and bias, and (2) imputing incompletely specified fire dates. The resulting estimates were 7.2 million unattended residential fires per year, a 69% decrease from the 1984 survey estimate of 22.9 million fires. During the same time period, fire department attended residential fires decreased by 36%. The greater decrease in unattended fires is at variance with the conjecture in the 1984 survey that increasing availability of smoke alarms would result in more fires detected at an earlier stage when they could be controlled by residents; a conjecture that would predict a greater decrease in attended rather than unattended fires.     

Avoiding neural network fine tuning by using ensemble learning: application to ball-end milling operations

Surface roughness plays a key role in the performance of machined components??specially dies and moulds??manufactured for the aerospace and automotive industries, among others. However, roughness can only be measured off-line after the part has been machined, when cutting conditions may no longer be adjusted to surface roughness requirements. A reliable surface roughness prediction application is presented in this paper. It is based on ensemble learning for vertical high-speed milling operations with ball-end mills for finishing operations on quenched steel 1.2344 (AISI H13) that are widely used in the manufacture of moulds and dies. The new approach was validated with an experimental dataset that includes geometrical tool factors, cutting conditions, dynamic factors and lubricant type. An intensive comparison with an artificial neural network approach for the same dataset is included, to reveal the improvements of the new technique over other well-established ones for this industrial problem. This comparison shows that ensemble learning can by-pass the time-consuming task of tuning neural network parameters and can also improve prediction model accuracy, both of which are features that could lead to greater use of these kinds of prediction models in real workshops. Finally, a methodology, based on this new approach, is presented, in order to illustrate how the prediction model can be used in workshops to optimize cutting conditions in terms of their surface quality and productivity.     

Nitroxide‐mediated synthesis of styrenic‐based segmented and tapered block copolymers using poly(lactide)‐functionalized TEMPO macromediators

Poly(styrene)‐poly(lactide) (PS‐PLA), poly (tert‐butyl styrene)‐poly(lactide) (PtBuS‐PLA) diblocks, and poly(tert‐butyl styrene)‐poly(styrene)‐poly(lactide) (PtBuS‐PS‐PLA) segmented and tapered triblocks of controlled segment lengths were synthesized using nitroxide‐mediated controlled radical polymerization. Well‐defined PLA‐functionalized macromediators derived from hydroxyl terminated TEMPO (PLA_T) of various molecular weights mediated polymerizations of the styrenic monomers in bulk and in dimethylformamide (DMF) solution at 120–130°C. PS‐PLA and PtBuS‐PLA diblocks were characterized by narrow molecular weight distributions (polydispersity index (M_w/M_n) < 1.3) when using the PLA_T mediator with the lowest number average molecular weight M_n= 6.1 kg/mol while broader molecular weight distributions were exhibited (M_w/M_n = 1.47‐1.65) when using higher molecular weight mediators (M_n = 7.4 kg/mol and 11.3 kg/mol). Segmented PtBuS‐PS‐PLA triblocks were initiated cleanly from PtBuS‐PLA diblocks although polymerizations were very rapid with PS segments ～ 5–10 kg/mol added within 3–10 min of polymerization at 130°C in 50 wt % DMF solution. Tapering from the PtBuS to the PS segment in semibatch mode at a lower temperature of 120°C and in 50 wt % DMF solution was effective in incorporating a short random segment of PtBuS‐ran‐PS while maintaining a relatively narrow monomodal molecular weight distribution (M_w/M_n ≈ 1.5). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Recombinant fusion proteins for the industrial production of disulfide bridge containing peptides: purification, oxidation without concatamer formation, and selective cleavage

The relative contributions of protein tyrosine kinases (PTKs) and protein kinase C isoenzymes (PKCs), a family of serine/threonine kinases, in integrin alpha(IIb)beta3 (glycoprotein IIb/IIIa) exposure are the subject of much controversy. In the present study we measured the effect of the PTK inhibitor herbimycin A and the PKC inhibitor bisindolylmaleimide I on 125I-fibrinogen binding to alpha(IIb)beta3 and on aggregation/secretion induced by different agonists. Dose-response studies showed complete inhibition of alpha(IIb)beta3 exposure by 30 micromol/L (ADP stimulation) and 35 to 40 micromol/L (alpha-thrombin stimulation) herbimycin A. In contrast, inhibition of exposure by bisindolylmaleimide I varied from none (for ADP and epinephrine), to 30% (for platelet-activating factor), and to approximately 80% (for alpha-thrombin). Studies with a submaximal dose of herbimycin A (approximately 50% inhibition of the ADP-response) and a maximal dose of bisindolylmaleimide I showed that optical aggregation had a similar sensitivity to the inhibitors as alpha(IIb)beta3 exposure with minimal interference by secreted ADP. Thus, the relative contributions of tyrosine and serine/threonine kinases in alpha(IIb)beta3 exposure and aggregation differ among the different agonists, with an exclusive role for PTKs in ADP- and epinephrine-induced responses and a role for both PTKs and PKCs in responses induced by platelet-activating factor and alpha-thrombin.     

Effects of Fluid Inertia on Finite-Length Squeeze-Film Dampers

The influence of fluid inertia on the SFD force response to circular-centered motions of arbitrary amplitude is analyzed in detail, For finite length, locally sealed SFDs, integro-differential equations are derived in terms of the mean flow components. Numerical predictions, using the finite-element method, show that the damping and added mass coefficients remain invariant as the Reynolds number increases from small values to a moderate Reynolds number equal to 10. An approximate, finite-length, solution for the fluid-film forces has been analytically obtained which accounts for the fluid-inertia effect as well as local end seal effects in symmetric SFD configurations. The approximate solution, strictly valid for small Reynold numbers (Re < 1), agrees well with the results from the numerical solution for most SFD configurations and orbit radii considered.