In this paper, we present a novel approach to model user request patterns in the World Wide Web. Instead of focusing on the user traffic for web pages, we capture the user interaction at the object level of the web pa...In this paper, we present a novel approach to model user request patterns in the World Wide Web. Instead of focusing on the user traffic for web pages, we capture the user interaction at the object level of the web pages. Our framework model consists of three sub-models: one for user file access, one for web pages, and one for storage servers. Web pages are assumed to consist of different types and sizes of objects, which are characterized using several categories: articles, media, and mosaics. The model is implemented with a discrete event simulation and then used to investigate the performance of our system over a variety of parameters in our model. Our performance measure of choice is mean response time and by varying the composition of web pages through our categories, we find that our framework model is able to capture a wide range of conditions that serve as a basis for generating a variety of user request patterns. In addition, we are able to establish a set of parameters that can be used as base cases. One of the goals of this research is for the framework model to be general enough that the parameters can be varied such that it can serve as input for investigating other distributed applications that require the generation of user request access patterns.展开更多
High spectral efficiency is essential in design of multimedia communication systems such as L-band mobile in addition to various requirements of transmission quality.Time-interleaved A/D converter(TI-ADC)is an effecti...High spectral efficiency is essential in design of multimedia communication systems such as L-band mobile in addition to various requirements of transmission quality.Time-interleaved A/D converter(TI-ADC)is an effective candidate to implement wide-band ADC with relatively slow circuits accounting for digital spectrum management.However,practical performance of TI-ADC is largely limited because of mismatches between different channels originated from manufacturing process variations.In this paper,a blind adaptive method is proposed to correct gain mismatch errors in TI-ADC,and it is verified through simulations on a two-channel TI-ADC.In proposed method,gain mismatch error is estimated and corrected in an adaptive scheme.Proposed compensated TI-ADC architecture is structurally very simple and hence suitable for realization in integrated circuits.Besides,proposed digital compensation algorithm not only is computationally efficient but also provides an improvement of 32.7 dB in the performance of two-channel TI-ADC.展开更多
文摘In this paper, we present a novel approach to model user request patterns in the World Wide Web. Instead of focusing on the user traffic for web pages, we capture the user interaction at the object level of the web pages. Our framework model consists of three sub-models: one for user file access, one for web pages, and one for storage servers. Web pages are assumed to consist of different types and sizes of objects, which are characterized using several categories: articles, media, and mosaics. The model is implemented with a discrete event simulation and then used to investigate the performance of our system over a variety of parameters in our model. Our performance measure of choice is mean response time and by varying the composition of web pages through our categories, we find that our framework model is able to capture a wide range of conditions that serve as a basis for generating a variety of user request patterns. In addition, we are able to establish a set of parameters that can be used as base cases. One of the goals of this research is for the framework model to be general enough that the parameters can be varied such that it can serve as input for investigating other distributed applications that require the generation of user request access patterns.
基金Iran’s Telecommunication Research Center(ITRC)(No.500/3653)
文摘High spectral efficiency is essential in design of multimedia communication systems such as L-band mobile in addition to various requirements of transmission quality.Time-interleaved A/D converter(TI-ADC)is an effective candidate to implement wide-band ADC with relatively slow circuits accounting for digital spectrum management.However,practical performance of TI-ADC is largely limited because of mismatches between different channels originated from manufacturing process variations.In this paper,a blind adaptive method is proposed to correct gain mismatch errors in TI-ADC,and it is verified through simulations on a two-channel TI-ADC.In proposed method,gain mismatch error is estimated and corrected in an adaptive scheme.Proposed compensated TI-ADC architecture is structurally very simple and hence suitable for realization in integrated circuits.Besides,proposed digital compensation algorithm not only is computationally efficient but also provides an improvement of 32.7 dB in the performance of two-channel TI-ADC.
