Efficient Monitoring Algorithm for Fast News Alerts

Recently, there has been a dramatic increase in the use of XML data to deliver information over the Web. Personal Weblogs, news Web sites, and discussion forums are now publishing RSS feeds for their subscribers to retrieve new postings. As the popularity of personal Weblogs and RSS feeds grows rapidly, RSS aggregation services and blog search engines have appeared, which try to provide a central access point for simpler access and discovery of new content from a large number of diverse RSS sources. In this paper, we study how the RSS aggregation services should monitor the data sources to retrieve new content quickly using minimal resources and to provide its subscribers with fast news alerts. We believe that the change characteristics of RSS sources and the general user access behavior pose distinct requirements that make this task significantly different from the traditional index refresh problem for Web search engines. Our studies on a collection of 10,000 RSS feeds reveal some general characteristics of the RSS feeds and show that, with proper resource allocation and scheduling, the RSS aggregator provides news alerts significantly faster than the best existing approach.     

A 60-GHz-Band Analog Optical System-on-Package Transmitter for Fiber-Radio Communications

We developed an analog optical system-on-package (SoP) transmitter for a 60-GHz-band radio-over-fiber (RoF) link. The SoP transmitter consisted of an electroabsorption modulator, radio frequency amplifiers, and a bandpass filter. The 60-GHz RoF wireless link was prepared to measure the performance of the SoP transmitter. The transmission characteristics of 64-quadrature amplitude modulation (64-QAM) data of the 60-GHz RoF wireless link, including the SoP transmitter, were investigated by measuring the error vector magnitude (EVM) and signal-to-noise ratio (SNR) with a baseband frequency. The EVM of the 60-GHz RoF wireless link was between 2.25% and 2.80%, and the SNR was between 27.36 and 29.31 dB from 140 and 770 MHz, at input baseband power of -9 dBm. The noise figure had the minimum of 8.44 dB at 500 MHz. We successfully transmitted digital community antenna television (CATV) system signals through the 60-GHz RoF wireless link, including the SoP transmitter. Digital CATV signals of 86 channels could be transmitted through the 60-GHz RoF wireless link, and the total throughput was found to be 2.61 Gb/s.     

Hypoglycemic effect of standardized Chrysanthemum zawadskii ethanol extract in high-fat diet/streptozotocin-induced diabetic mice and rats

Food Science and Biotechnology - Chrysanthemum zawadskii (CZ) is a perennial herb belonging to the Asteraceae family. CZ is used medicinally to treat inflammatory and uterine diseases in Asia. CZ...     

Parametric study on the fatigue life of railways under rolling contact fatigue by three-dimensional numerical analysis

The current paper presents the results of parametric analyses on the stress intensity factor (SIF) of railways with inclined cracks under rolling contact fatigue (RCF). A 3D finite element (FE) model was proposed to demonstrate the shear mechanism in RCF. The feasibility of the suggested numerical model was verified through the SIF (K) obtained from advanced 3D FE analysis compared with existing 2D FE results. Based on the series of FE analyses, the sensitivity analysis on the cracked depth, surface/crack friction coefficients, and inclined angle, which mainly affected SIF history at the cracked tip, was examined. SIF distributions for various locations of the wheel along the cracked tip were also presented.     

Multiscale modeling and control of Kappa number and porosity in a batch-type pulp digester

This work proposes a multiscale modeling and model-based feedback control framework for the delignification process in a batch-type pulp digester. Specifically, we focus on a hardwood chip in the digester and develop a multiscale model capturing both the evolution of microscopic properties such as the pore size and shape distributions in the solid phase and the dynamic changes in the temperature and component concentrations in the liquor phase. While the macroscopic model adopts the continuum hypothesis based on the Purdue model, a novel microscopic model is developed using a kinetic Monte Carlo algorithm, accounting for the dissolution of lignin, cellulose, and hemicellulose contacting the liquor phase. A reduced-order model was built to design a Luenberger observer for state estimation, which is then used to develop a model-based control system. The simulation results demonstrated that the proposed methodology was able to regulate both the Kappa number and porosity to desired values.     

Application of offset-free Koopman-based model predictive control to a batch pulp digester

This work presents the application of a Koopman operator approach to a batch pulp digester. To manufacture paper products with desired properties, it is essential to consider both macroscopic and microscopic attributes of pulp. However, the complexity of multiscale dynamics of pulping processes hinders proper control system design. Therefore, we utilize extended dynamic mode decomposition (EDMD), which is based on Koopman operator theory, to derive a global linear representation of a pulp digester. Then, we design an offset-free Koopman-based model predictive control (KMPC) system to regulate the Kappa number and cell wall thickness (CWT) of fibers at a batch pulp digester while compensating for the influence of plant-model mismatch and disturbance during operation. The numerical experiments demonstrate that the linear state-space model, obtained via EDMD, properly predicts the behavior of a batch pulp digester, and the designed offset-free KMPC system successfully drives the Kappa number and CWT to set-point values.     

Metalorganic chemical vapor deposition of Sr x TiyO z thin films by using mixed metal precursorsO z thin films by using mixed metal precursors

Strontium titanate (Sr _x Ti _y O _z ) thin films were prepared by a chemical vapor deposition method using gaseous compounds, obtained by vaporizing a solid mixture of Sr(dpm)₂ and Ti(O-iPr)₂(dpm)₂ in one step, as the metal sources. The compositions of the films changed in proportion to the ratio of the precursors in the solid mixture, which is contrary to the case of films obtained from a mixture of individual precursor vapors. In the latter case, the film composition was not proportional to the mixing ratio of the precursors. The strontium titanate concentration in the film was changed by the deposition temperature even when the Sr/Ti ratio of the feed was fixed, i.e., the Sr/Ti ratio in the film decreased at high temperatures. An SrTiO₃ film, with an Sr/Ti ratio of 1/1, was obtained at 450 ‡C by using vapors from a solid mixture containing the metal precursors at a Sr/Ti of 1/1. The temperature, 450 ‡C in this case, was lower than that for producing the same film composition by a liquid injection method, 550 ‡C. The decomposition of the Ti and Sr precursors included in the solid mixture and possible reactions between them at elevated temperatures were investigated by thermogravimetry, differential scanning calorimetry, and mass spectrometry. When the solid mixture was heated, the Sr-O bond, that connected Sr to the dpm ligand, was dissociated at temperatures lower than 100 ‡C and the isopropoxide ligand of the Ti precursor was dissociated from the Ti atom at temperatures below 150 ‡C. At 162 ‡C, Ti(O-iPr)₂(dpm)₂ melted, forming an oligomer by reaction with surrounding Ti and Sr precursors. This reaction was confirmed by the presence of a mass peak at m/e=585, corresponding to a hetero-metallic compound containing Sr and Ti. The hetero-metallic compound vaporized at temperatures below 200 ‡C and eventually participated in the formation of a SrTiO₃ film.     

The modified embedded-atom method interatomic potentials and recent progress in atomistic simulations

Atomistic simulations such as molecular dynamics and Monte Carlo are widely used for understanding the material behavior at a more fundamental level, e.g., at the atomic level. However, there still exist limitations in the variety of material systems, specimen size and simulation time. This article briefly outlines the formalism and performance of the second nearest-neighbor modified embedded-atom method, an interatomic potential formalism applicable to a wide range of materials systems. Recent progresses made to overcome the inherent size and time limitations of atomistic simulations are also introduced along with the challenges still remaining in extending their applicability. Finally, the authors release all the potential parameter sets for elements and alloy systems, and relevant homemade atomistic simulation codes based on the interatomic potential formalism with a user guide.     

Formation and optimization of undercut-microholes in InGaN light emitting diodes by using wet chemical etching

We report on the formation and optimization of undercut-microholes (UM) generated by a wet etching process. GaN epilayers with 6 μm and 15 μm polygonal holes (PH) were grown by using selective metal organic chemical vapor deposition under identical growth conditions. The samples were wet etched with either a KOH solution or a mixed H₃PO₄:H₂SO₄ solution. Both kinds of etching solution produced the formation of UM. In the case of the etching produced with the mixed H₃PO₄:H₂SO₄ solution, the angle of UM was varied with an increase of H₂SO₄ in the solution. The etching produced by the KOH solution was very simple, and it formed a clear UM with an angle of 62°. This was achieved without etching the hard mask because of the selective etching and crystallographic characteristics of the GaN. UM were optimized through etching with PH structures, and the results showed formation of clear UM in a 15 μm PH structure.     

A 48 GHz 196 dB-FOM LC VCO With Double Cap-Degeneration Negative-Resistance Cell

This letter presents a 48-GHz capacitively emitter-degenerated LC voltage controlled oscillator (VCO) with double cross-coupled pair showing higher and lower input capacitance than typical cross-coupled pairs. The phase noise of the proposed LC VCO is measured as 114.5 dBc/Hz at 1 MHz offset from 48 GHz carrier, and a current of 6 mA is drawn in the VCO circuit. The proposed VCO shows an excellent figure of merit of 196 dB.