One way of improving the performance of cellular networks is to build a second layer of macrocells on top of the microcell level. The system performance can further be increased by using guard channels and allowing ca...
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It is a large collection of software supporting the planning, execution and reporting of work activities, but these systems are mainly created to be run in a distributed wired network, or as standalone systems. The sy...
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ISBN:
(纸本)0889863415
It is a large collection of software supporting the planning, execution and reporting of work activities, but these systems are mainly created to be run in a distributed wired network, or as standalone systems. The systems do not directly support the mobile part of work. The cost and effort to make such systems available to mobile users are not just an issue of making adjustments to the network protocols, but also to be able to adapt the system to a heterogeneous set of hardware spanning from small mobile phones to portable PCs. This paper presents experiences from migration of a Web-based task administration system to a mobile environment. Different solutions of system adaptation are discussed, and a prototype of a system to support mobile work is presented and evaluated.
This paper investigates the effect of parameter selection for the decision feedback equalization (DFE) on communication performance through a dispersive underwater acoustic wireless channel (UAWC). A DFE based on mini...
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This paper investigates the effect of parameter selection for the decision feedback equalization (DFE) on communication performance through a dispersive underwater acoustic wireless channel (UAWC). A DFE based on minimum mean-square error (MMSE-DFE) criterion has been employed in the implementation for evaluation purposes. The output from the MMSE-DFE is input to the decoder to estimate the transmitted bit sequence. The main goal of this experimental simulation is to determine the best selection, such that the reduction in the computational overload is achieved without altering the performance of the system, where the computational complexity can be reduced by selecting an equalizer with a proper length. The system performance is tested for BPSK, QPSK, 8PSK and 16QAM modulation and a simulation for the system is carried out for Proakis channel A and real underwater wireless acoustic channel estimated during SPACE08 measurements to verify the selection.
In this paper, we obtain optimum continuous time wavelet waveforms for chip pulse shaping waveforms of DS-CDMA signals. We first derive a performance measure for a DS-CDMA system, which is the normalized interference ...
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In this paper, we obtain optimum continuous time wavelet waveforms for chip pulse shaping waveforms of DS-CDMA signals. We first derive a performance measure for a DS-CDMA system, which is the normalized interference in terms of the chip waveform. Then, we design optimum wavelet waveform to minimize the interference under a bandwidth constraint by utilizing the relationship between wavelets and FIR filter banks. We evaluate the probability of error of the optimum wavelets, and they are compared with conventional chip waveforms such as raised cosine and sinc.
Information technology (IT) is the most dynamic technology, having the greatest impact on social development, both, directly and indirectly. Its multiplier effect in creation of wealth and improving the quality of lif...
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Information technology (IT) is the most dynamic technology, having the greatest impact on social development, both, directly and indirectly. Its multiplier effect in creation of wealth and improving the quality of life is perhaps higher than any other technology known to humankind. IT is an enabling technology that can improve our productivity in almost every sector of the economy. Our societies are really being transformed into "information societies", where these new capabilities are employed so as to allow for new practices across practically the whole range of social and economic activities. This paper illustrates neatly the pathways to build the global information society with new information and communication technologies (ICTs).
In this paper bounded model checking of asynchronous concurrent systems is introduced as a promising application area for answer set programming. As the model of asynchronous systems a generalization of communicating ...
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In our society, the concept of sharing information is growing that lead to the emerging crowdsensing technology where a crowd of connected devices having sensors is used to sense and collect information. However, priv...
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It is important to model the substrate coupling for mixed-signal circuit designs today. This paper presents an improved direct boundary element method (DBEM) for substrate resistance calculation, where only the bounda...
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It is important to model the substrate coupling for mixed-signal circuit designs today. This paper presents an improved direct boundary element method (DBEM) for substrate resistance calculation, where only the boundary of substrate volumes is discretized and only the free-space Green function is used. At first, we discard some inessential unknowns to compress the linear system without accuracy loss. Then we make the coefficient matrix sparser. In this way, solving the linear system is greatly accelerated. Experiments on various substrates validate that DBEM is several to tens of times faster than DCT-accelerated Green's function methods and the eigendecomposition method, while preserving high accuracy. Besides, another experiment shows that this method is versatile for irregular substrates. Copyright 2005 ACM.
The error properties of state-feedback/observer (SFO) topologies of modern control systems is easier to study using equivalent transfer function representations (TFR's). This approach is used to study why an obser...
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In this paper, a new modified normalized least mean square (NLMS) algorithm for updating the coefficients of an adaptive FIR digital filter (ADF) is proposed. The new adaptive algorithm is modified by using the preset...
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