Errors resulting from the reflectivity of calibration targets

For a microwave total-power radiometer, we consider the error introduced by neglecting the difference in the antenna reflection coefficient between when it views a distant scene and when it views a nearby calibration target. An approximate expression is presented for the error, and measurements are described that enable one to estimate the resulting uncertainty in the measured brightness temperature. The measurement results are presented for several combinations of antenna and calibration target. The resulting uncertainty ranges from about 0.1 K to several kelvins for the representative cases considered.     

Extending ventilation duration estimations approach from adult toneonatal intensive care patients using artificial neural networks

In earlier work, the research group successfully used artificial neural networks (ANNs) to estimate ventilation duration for adult intensive care unit (ICU) patients. The ANNs performed well in terms of correct classification rate (CCR) and average squared error (ASE) classifying the outcome into two classes: whether patients were ventilated for less than/equal to or for more than 8 h (⩽ or >). The objective of new work was to apply this adult model to the estimation of ventilation with neonatal ICU (NICU) patient records. The performance obtained with the neonatal patients was comparable to that previously found with the adult database, again as measured in terms of a maximum CCR and a minimum ASE. The effectiveness of using the weight-elimination technique in controlling overfitting was again validated for the neonatal patients as it had been for our adult patients. It was concluded that the approach developed for ICU adult patients was also successfully applied to a different medical environment: neonatal ICU patients     

Emulsifier Effects on Pasting Properties of Wheat Flour Extrudates with/without Sucrose and Shortening

The objective of this study was to determine the effects of emulsifier types and concentrations, plus the addition of sucrose and shortening on wheat flour extrudates. Ground extrudate pasting properties were measured in the rapid viscoanalyser (RVA). Four pasting parameters were determined from the RVA curve: peak time (PT), peak viscosity (P), breakdown viscosity (H), and initial slope (IS). Emulsifier types and the addition of sucrose and shortening significantly affected PT, P, H, and IS. Emulsifier concentration significantly influenced PT and H. Emulsifiers significantly increased PT and H and decreased P and IS. Glyceryl monostearate had the greatest effects on these parameters. Sucrose and shortening generally enhanced the effects of emulsifiers on pasting properties.     

Quantum interference effects in semiconductors: a bibliography

The bibliography has been compiled as an introduction and study guide to this field. The papers listed describe the extensive theoretical and experimental results that have been obtained on quantum interference effects and discuss possible application areas. Works of a fundamental nature concerning phenomena that are basic to all semiconductor behavior have not been included. Articles on the properties and band structure of semiconductors, which are essential to a complete understanding of quantum interference effects, have not been included. Conference papers, though frequently very important, have not been included to conserve space. The papers are listed alphabetically according to the first author's surname. As in the compilation of any bibliography, numerous valuable and pertinent articles have probably been inadvertently omitted     

Optical determination of dental pulp vitality

In this preliminary study, we explored the feasibility of employing photoplethysmography and pulse oximetry to assess the status of the blood circulation in the dental pulp. A simple photometer that measures diffuse light transmission at 575 nm was built to record tooth plethysmograms, and the ability to distinguish vital from surgically devitalized teeth of a dog using plethysmography was demonstrated. As an extension of the photoplethysmographic technique, red-infrared pulse oximetry applied to the measurement of the oxygen saturation (SO2) of blood in the pulp was also examined using an in vitro test setup. Results suggest that the measurement of relative SO2 changes is feasible, but standard dual-wavelength pulse oximetry does not enable determination of SO2 independent of tooth geometry and sensor placement.     

Multijoule performance of the photolytically pumped XeF(C→A) laser

An XeF(C rightarrow A) laser with output up to 5.8 J/pulse has been demonstrated. The photolytic pumping scheme begins withe-beam excitation of xenon to produce Xe*2fluorescence at 172 nm. This VUV radiation is transmitted through an array of CaF2windows into the laser cell, where it photodissociates XeF2to produce primarily XeF(Bfrac{1}{2}). Collisions with N2buffer gas relax the excited states to XeF(Cfrac{3}{2}), which lases on a transition centered at 481 nm and continuously tunable over more than ±35 nm. Typical values of the experimental parameters were as follows. The 420 kV, 1 me-beam source delivered an average current of 10 A/cm²over an aperture 14 × 100 cm for pulse lengths up to 1 μs. Totale-beam energy available was 3.5 kJ, of which 2.4 kJ was deposited in the xenon. The total VUV energy radiated was 720 J, of which 115 J was coupled into the laser cell. This produced 32 J of available XeF* energy, of which up to 18 percent was extracted as laser energy. The total system efficiency was 0.2 percent. Optimized designs should achieve better than 1 percent efficiency.     

A simulation as a service cloud middleware

Many seemingly simple questions that individual users face in their daily lives may actually require substantial number of computing resources to identify the right answers. For example, a user may want to determine the right thermostat settings for different rooms of a house based on a tolerance range such that the energy consumption and costs can be maximally reduced while still offering comfortable temperatures in the house. Such answers can be determined through simulations. However, some simulation models as in this example are stochastic, which require the execution of a large number of simulation tasks and aggregation of results to ascertain if the outcomes lie within specified confidence intervals. Some other simulation models, such as the study of traffic conditions using simulations may need multiple instances to be executed for a number of different parameters. Cloud computing has opened up new avenues for individuals and organizations with limited resources to obtain answers to problems that hitherto required expensive and computationally-intensive resources. This paper presents SIMaaS, which is a cloud-based Simulation-as-a-Service to address these challenges. We demonstrate how lightweight solutions using Linux containers (e.g., Docker) are better suited to support such services instead of heavyweight hypervisor-based solutions, which are shown to incur substantial overhead in provisioning virtual machines on-demand. Empirical results validating our claims are presented in the context of two case studies.     

Characterization of a Flip-Flop Metastability Measurement Method

We characterize a proposed metastability measurement system in which asynchronous data input and sampling clock frequencies trigger metastability. We develop an equation describing the time interval between data and clock inputs for practical frequencies and show that it takes on discrete values in the absence of jitter and that the presence of jitter perturbs these values. Finally, we present experimental results supporting our characterization     

An array processor for general purpose digital image compression

A new VLSI processor (DIP chip) for image compression is presented which combines principles of multipipeline and array processing. The device is not specific to any one image compression algorithm and can be regarded as a general purpose processor. The chip has been implemented using a CMOS 1.0-μm process on a 14.4×13.5-mm² die. An internal clock frequency of 40 MHz results in 1.2×10⁹ operations/s on 8-bit data. Solutions to problems associated with the large bandwidth required, for both image data and instruction streams, is the main aim of the paper. The necessary problem of increasing the array clock frequency relative to the input/output clock frequency without the need for a large on-chip instruction cache or fast external clock speeds is also addressed     

Design and fabrication of monolithically integrated DFB laser-wavelength duplexer transceivers for TPON/BPON access links

The fabrication and characterisation of monolithically integrated OEIC transceivers for use in optical subscriber access links are reported. A design incorporating DFB lasers, wavelength duplexers and a monitor photodiode, specific to the TPON/BPON passive optical network configuration is presented.<>