Research on fine tuning stabilization properties has received attention for more than a decade. This paper presents probabilistic algorithms for fault containment. We demonstrate two exercises in fault containment in a weakly stabilizing system, which expedite recovery from single failures, and confine the effect of any single fault to the constant-distance neighborhood of the faulty process. The most significant aspect of the algorithms is that the fault gap, defined as the smallest interval after which the system is ready to handle the next single fault with the same efficiency, is independent of the network size. We argue that a small fault gap increases the availability of the fault-free system. 相似文献
One strategy for alleviating excess latency (delay) in the Internet is the caching of web content at multiple locations. This
reduces the number of hops necessary to reach the desired content. This strategy is used for web content such as html pages,
images, streaming video, and Internet radio. The network of servers which store this content, and the collections of objects
stored on each server, is called a content distribution network (CDN). In order to optimally design a CDN, given a network
topology with available server storage capacity at various points in the network, one must decide which object collections
to place on each server in order to achieve performance or cost objectives. The placements must be within the storage limits
of the servers and must reflect the request patterns for each collection of objects to be cached. Researchers have suggested
formulations for the CDN problem which address performance by minimizing latency (the average number of hops is a commonly
accepted measure of latency) from client to content, or formulations that focus on minimizing cost of storage and/or bandwidth.
In this research, we develop a model which allows for the simultaneous treatment of performance and cost, present examples
to illustrate the application of the model and perform a detailed designed experiment to gain insights into cost/hops tradeoff
for a variety of network parameters. 相似文献
Indian economy has been facing the twin issues of mounting trade imbalance and persisting inflation. Oil constitutes one‐third of the country's total imports and is considered to have wide‐ranging impact on its economy. This paper empirically examines how oil price fluctuations impact Indian economy through various channels, viz. real sector, monetary policy, external trade, exchange rate and investment. The results of cyclical correlation analysis suggest that oil is pro‐cyclical to output, price level, stock market, gold, interest rate and foreign exchange reserves, while it is counter‐cyclical to money supply, net exports and exchange rate. Also, it is found that oil Granger causes output, general price level and net exports. The study employs vector auto‐regression (VAR) analysis and examines variance decomposition to capture the linear inter‐dependencies among the variables. The structural stability tests demonstrate that there is no evidence of structural break in the VAR model, confirming the reliability of estimated relationships under the VAR model. 相似文献
Imaging of iron-based nanoparticles (NPs) remains challenging because of the presence of endogenous iron in tissues that is difficult to distinguish from exogenous iron originating from the NPs. Here, an analytical cascade for characterizing the biodistribution of biomedically relevant iron-based NPs from the organ scale to the cellular and subcellular scales is introduced. The biodistribution on an organ level is assessed by elemental analysis and quantification of magnetic iron by electron paramagnetic resonance, which allowed differentiation of exogenous and endogenous iron. Complementary to these bulk analysis techniques, correlative whole-slide optical and electron microscopy provided spatially resolved insight into the biodistribution of endo- and exogenous iron accumulation in macrophages, with single-cell and single-particle resolution, revealing coaccumulation of iron NPs with endogenous iron in splenic macrophages. Subsequent transmission electron microscopy revealed two types of morphologically distinct iron-containing structures (exogenous nanoparticles and endogenous ferritin) within membrane-bound vesicles in the cytoplasm, hinting at an attempt of splenic macrophages to extract and recycle iron from exogenous nanoparticles. Overall, this strategy enables the distinction of endo- and exogenous iron across scales (from cm to nm, based on the analysis of thousands of cells) and illustrates distribution on organ, cell, and organelle levels. 相似文献
This article aims to explore the impressive impact of emerging parameters on transient fully evolved free convective flow inside a vertical cylinder containing a porous material. The mathematical formulation of the model related to the considered physical circumstance is presented under compatible boundary conditions. Closed‐form solutions are received for the velocity field, the temperature distribution, mass flux, skin friction, and the Nusselt number in terms of Bessel functions and modified Bessel functions of the first kind. Impressive effects of parameters such as the Darcy number , Prandtl number , viscosity ratio , and also time on both the velocity and temperature distribution have been explored employing graphs and tables. It is irradiated by analysis that flow erection, heat transfer rate, skin friction, and mass flux are admirably impacted by the Prandtl number, the Darcy number, viscosity ratio parameter, and time. It is found that both the velocity and temperature field profiles rise with the rising value of time and ultimately attain their steady state. Moreover, the Prandtl number and the viscosity ratio parameter reduce the velocity profiles, while the reverse phenomenon occurs with the Darcy number. 相似文献
The thermoeconomic behaviour of a nanoparticle seeded single effect LiBr‐H2O absorption refrigeration system (ARS) is investigated for a small scale application. In the proposed method, alumina nanoparticles with volume concentrations of 3%, 5%, and 7% are dispersed into an aqua lithium bromide solution. The multiobjective heat transfer search algorithm is employed to examine the design trade‐off between the coefficient of performance (COP) and total annualized cost (TAC). To analyze the overall performance of the system, the influence of five design parameters, namely the temperatures of the generator, absorber, evaporator, condenser and heat exchanger pipe diameter, are studied. It is found that with an increase in the COP, the TAC of the system is initially raised marginally, and after that, raised rigorously with further increment. The comparative results indicate that the COP and TAC of the nanofluid based ARS system are increased by about 7% and decreased by about 3.2%, respectively, corresponding to the Pareto points of the base ARS system. A lower break‐even point of about 2.6 years is achieved for the ARS system containing nanoparticles compared to the base ARS system. Overall, the ARS system containing 5% nanoparticles is the best solution from a thermodynamic and economic point of view. 相似文献
The influence of Newtonian heating/cooling in the presence of heat source/sink has been investigated on laminar free convective flow in a vertical annular permeable region. The mathematical model for the problem has been considered as a boundary value problem consisting of two simultaneous ordinary differential equations. The boundary value problem has been transformed to nondimensional form. This has given rise to a number of parameters representing both geometrical and physical features of the problem. Closed‐form analytical solutions of the governing equations have been obtained for two different cases of internal heat generation/absorption. To assess the effects of governing parameters on the fluid velocity and temperature, a number of profiles of these field variables have been presented. The efficacy of the distinct processes on the field variables has been discussed extensively. The main outcome obtained in this study is that the velocity as well as temperature is enhanced in the case of the Newtonian heating while the opposite behavior occurs in the Newtonian cooling for both cases of source and sink. Furthermore, the influence of the governing parameters has been shown on the skin friction, volume flow rate, and the Nusselt number. 相似文献
A convergent strategy for the synthesis of biologically relevant C4‐substituted indole scaffolds was demonstrated using Pd(II)‐catalyzed remote C−H functionalization of indoles and azaindoles. The reaction displays high regioselectivity for the C4‐position of indole‐3‐carbaldehydes using glycine as an inexpensive transient directing group. Notable features of this transformation include the selective formation of six‐membered palladacyle and excellent functional group tolerance.
Objective: Innovation in material science has made it possible to fabricate a pharmaceutical material of modifiable characteristics and utility, in delivering therapeutics at a sustained/controlled rate. The objective of this study is to design and optimize the controlled release transdermal films of S-Amlodipine besylate by intercalating hydrophilic and hydrophobic polymers.
Methods: 3(2) factorial design and response surface methodology was utilized to prepare formulations by intercalating the varied concentration of polymers(A) and penetration enhancer(B) in solvent. The effect of these independent factors on drug release and flux was investigated to substantiate the ex-vivo, stability and histological findings of the study.
Results: FTIR, DSC revealed the compatibility of drug with polymers; however, the semicrystallinity in drug was observed under PXRD. SEM micrographs showed homogeneous dispersion and entanglement of drug throughout the matrix. Results from the permeation study suggested the significant effect of factors on the ex vivo permeation of drug. It was observed that drug release was found to be increased with an increase in hydrophilic polymer concentration and PE. The formulations having polymers (EC:PVPK-30) at 7:3 showed maximum drug release with highest flux (102.60?±?1.12?µg/cm2/h) and permeability coefficient (32.78?±?1.38?cm/h). Significant effect of PE on lipid and protein framework of the skin was also observed which is responsible for increased permeation. The optimized formulation was found to be stable and showed no-sign of localized reactions, indicating safety and compatibility with the skin.
Conclusion: Thus, results indicated that the prepared intercalated transdermal matrix can be a promising nonoral carrier to deliver effective amounts of drug. 相似文献
The experimental results of an air-core pulse transformer are presented, which is very compact (<10 Kg in weight) and is primed by a capacitor bank that is fabricated in such a way that the capacitor bank with its switch takes the shape of single-turn rectangular shaped primary of the transformer. A high voltage capacitor assembly (pulse-forming-line capacitor, PFL) of 5.1 nF is connected with the secondary of transformer. The transformer output voltage is 160 kV in its second peak appearing in less than 2 μS from the beginning of the capacitor discharge. The primary capacitor bank can be charged up to a maximum of 18 kV, with the voltage delivery of 360 kV in similar capacitive loads. 相似文献
