Impact of power-supply noise on timing in high-frequency microprocessors

This paper analyzes the impact of power-supply noise on the performance of high-frequency microprocessors. First, delay models that take this noise into account are proposed for device-dominated and interconnect-dominated timing paths. For typical circuits, it is shown that the peak of the noise is largely irrelevant and that the average supply voltage during switching is more important. It is then argued that global differential noise can potentially have a greater timing impact than common-mode noise. Finally, realistic values for the model parameters are measured on a 2.53-GHz Pentium4 microprocessor using a 130-nm technology. These values imply that the power-supply noise present on the system board reduces clock frequency by 6.7%. The model suggests that the frequency penalty associated with this power-supply noise will steadily increase and reach 7.6% for the 90-nm technology generation.     

A general enthalpy method for modeling solidification processes

In the present work, a general implicit source-based enthalpy method is presented for the analysis of solidification systems. The proposed approach is both robust and efficient. The performance of the method is illustrated by application to a number of problems taken from recent metallurgical literature.     

Analysis of Caching and Replication Strategies for Web Applications

Developers often use replication and caching mechanisms to enhance Web application performance. The authors present a qualitative and quantitative analysis of state-of-the art replication and caching techniques used to host Web applications. Their analysis shows that selecting the best mechanism depends heavily on data workload and requires a careful review of the application's characteristics. They also propose a technique for Web practitioners to compare different mechanisms' performance on their own     

Energy and Trust Management Framework for MANET using Clustering Algorithm

In General, Mobile Ad-Hoc Network (MANET) has limited energy resources, and it cannot recharge itself. This research goal focuses on building a power management scheme that saves energy in the MANET. Due to power instability, there is a chance that cluster heads fail and function incorrectly in cluster-based routing. As a result, instability occurs with the cluster heads while collecting data and communicating with others effectively. This work focuses on detecting the unstable cluster heads, which are replaced by other nodes implementing the envisaged self-configurable cluster mechanism. A self-configurable cluster mechanism with a k-means protocol approach is proposed to designate cluster heads effectively. The proposed k-means procedure is based on periodic irregular cluster head rotations or altering the number of clusters. We also propose a trust management mechanism in this research to detect and avoid MANET vulnerabilities. Because of the continuously changing topology and limited resources (power, bandwidth, computing), the trust management algorithm should only use local data. Consequently, compared to traditional protocols, the proposed approach with the k-means procedure and its experimental results show lower power usage and provide an optimal system for trust management.

     

Extraction of S‐parameters from time domain reflectometry and transmission measurements using rational functions

The extraction of the broad band S‐parameter response from transient reflection and transmission measurements is discussed. The proposed method uses the generalized pencil‐of‐function method, recursive deconvolution, and calibration structures to obtain a response using rational functions. A low loss printed circuit board plane and a lossy thin film plane are characterized to capture the two‐port S‐parameters. The results are compared with network analyzer measurements. The effects of the measurement parameters such as the sampling interval, time window, and number of averages are shown. The effect of time jitter on the extracted frequency response is quantified through repeated measurements. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 74–85, 2003.     

Improvement of tea leaves fermentation with Aspergillus spp. pectinase

The pectinase enzymes isolated from Aspergillus spp., A. indicus, A. flavus and A. niveus were used for fermentation of tea leaves. The enzymes were purified and characterized. The effect of both crude enzyme preparation and purified pectinase enzymes on the improvement of tea leaf fermentation were determined in terms of theaflavin, thearubigin, high polymerized substances, total liquor colour, dry matter content and total soluble solids of the tea produced. The crude enzyme preparations obtained from ethanol precipitation were found to be more effective in improving tea leaf fermentation than the purified pectinase enzymes.     

PulseNet standardized protocol for subtyping Listeria monocytogenes by macrorestriction and pulsed-field gel electrophoresis

PulseNet is a national network of pubic health and food regulatory laboratories established in the US to detect clusters of foodborne disease and respond quickly to foodborne outbreak investigations. PulseNet laboratories currently subtype Escherichia coli O157:H7, non-typhoidal Salmonella, and Shigella isolates by a highly standardized 1-day pulsed-field gel electrophoresis (PFGE), and exchange normalized DNA "fingerprint" patterns via the Internet. We describe a standardized molecular subtyping protocol for subtyping Listeria monocytogenes that was recently added to PulseNet. The subtyping can be completed within 30 h from the time a pure culture of the bacteria is obtained.     

A Mixed Integer Stochastic Optimization Model for Settlement Risk in Retail Electric Power Markets

Recent changes in the U.S. electric power markets have contributed to volatility in hourly prices and loads. In this paper we consider the position of the electric power retailer who typically contracts with suppliers and end-users and must provide future load requirements to the suppliers. As part of this energy supply chain, the retailer is faced with great uncertainty in both market prices as well as end-user loads. Based on actual data for the PJM market covering Pennsylvania, New Jersey, and Maryland, we develop a probabilistic optimization model to optimize the net profits for the retailer for a forecast time horizon (typically one or more hours) given the cumulative performance in previous time periods (hours). The resulting model is formulated as a mixed integer linear program with binary variables due to the disjunctive nature of certain forward load estimation bandwidth tolerance constraints. In addition, we also provide an existence result to this optimization model. Lastly, we present a numerical example of the optimization model to validate its workings and provide some insight into model sensitivities.     

Process standardization for optimal virus recovery and removal of substrate DNA and bovine serum proteins in Vero cell-derived rabies vaccine

Purification of a rabies vaccine by a single zonal centrifugation run was replaced by two runs with optimal standardization of the sucrose density gradient. As a result, significant reductions in the levels of substrate DNA and bovine serum protein in the Vero cell-derived human rabies vaccine were achieved. Following many trials, for the first run, loading of the 3.2-l capacity K-3 rotor with 1800 ml of 60% sucrose solution and 1400 ml of vaccine PBS buffer solution gave a satisfactory linear gradient. However, after the first run, the substrate DNA and bovine serum contents exceeded the required levels. After protamine sulphate and Tween-80 treatment of the concentrated inactivated material, a second run using the same procedure as in the first run was tried. However, these purification procedures resulted in low virus recovery. To achieve optimal virus recovery, and removal of substrate DNA and bovine serum protein, the peak fractions from the first run as indicated by the haemagglutination, sucrose concentration, and optical density values were pooled and the sucrose concentration of the pooled fractions was increased to 60%. A second (flotation) run was then carried out. Using this method, the virus recovery rate was more than 95% that of the first run, and the levels of cellular DNA and bovine serum protein were well within the acceptable limits of less than 100 pg/dose and one part per million, respectively. The substrate DNA was quantified by both radioactive labeling and non-radioactive biotin labeling methods. For the quantification of calf serum protein, a counter-immunoelectrophoresis method was developed and effectively applied. A potency assay was performed using the National Institutes of Health (NIH) and well-standardized in vitro single radial immuno diffusion (SRD) methods. Finally, an immunogenicity study was conducted with human volunteers and the results were confirmed by a rapid fluorescent focus inhibition test (RFFIT).     

Oxygen Potential in the System UMoO6/UMoO5 by the Solid Oxide Electrolyte Emf Method

The emf of the galvanic cell Pt|UMoO₆UMoO₅|ZrO₂-Y₂O₃|O₂(air, Po₂=0.21 atm)|Pt, measured from 776 to 1127 K, was determined to be E = 751.7−0.4909 ±4.3 mV. Using the standard Gibbs energy of formation, ^fΔG°, for UMoO₆ reported in the literature from transpiration studies, the ^fΔG° for UMoO₅ is calculated to be ^fΔG°〈UMoO₅〉=−1816.9+0.3748T±6.0 U-mol⁻¹ The magnitudes of the standard entropies of formation, ^fΔS°, for UMoO₆ and UMoO₅ were evaluated from those values reported for the binary oxides which constitute the ternary compounds.