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Use of signal quality measurements to gain efficiency in the analysis of cDNA microarray data

Journal of Genetics and Genomics 2010年第4期37卷 265-279页

作者： Tracy L Bergemann Division of Biostatistics University of Minnesota

This research provides a new way to measure error in microarray data in order to improve gene expression analysis. Microarray data contains many sources of error. In order to glean information about mRNA expression levels, the true signal must first be segregated from noise. This research focuses on the variation that can be captured at the spot level in cDNA microarray images. Variation at other levels, due to differences at the array, dye, and block levels, can be corrected for by a variety of existing normalization procedures. Two signal quality estimates that capture the reliability of each spot printed on a microarray are described. A parametric estimate of within-spot vari ance, referred to here as σ^2spot, assumes that pixels follow a normal distribution and are spatially correlated. A non-parametric estimate of error, called the mean square prediction error （MSPE）, assumes that spots of high quality possess pixels that are similar to their neighbors. This paper will provide a framework to use either spot quality measure in downstream analysis, specifically as weights in regression models. Using these spot quality estimates as weights can result in greater efficiency, in a statistical sense, when modeling mi- croarray data.

关键词： microarrays signal quality prediction measurement error models

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Analysis Method for GNSS signal quality Based on Constellation Diagram

Analysis Method for GNSS Signal Quality Based on Constellati...

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第五届中国卫星导航学术年会

作者： Wang Ying Su Zhe Meng Yansong Tao Xiaoxia China Academy of Space Technology（Xi’an）

ISBN: (纸本)9783642547362

Modern Global Navigation Satellite System（GNSS） signals commonly use very complex modulation and combining method to get diversified and high quality service of navigation,positioning and *** that reason,analysis methods of communication signal are not sufficient to reflect navigation signal *** on the analysis of differences between navigation signal and general communication signal,this paper noted concerns and research method of constellation diagram,through real signal generation system,analysed the differences between real signal and ideal signal,proved the method is intuitive and credible through other signal quality analysis methods,and can display more problems of signal generation system and signal quality.

关键词： constellation diagram satellite navigation signal quality

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Array (Smart) Antennas Improve GSM Performance

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International Journal of Communications, Network and System Sciences 2024年第1期17卷 1-10页

作者： Cornelius A. D. Pahalson Nuhu Habila Hyat Markus Gaga Department of Science School of Science and Technology Plateau State Polytechnic Barkin Ladi Nigeria

As wireless data applications over cellular networks become more widespread, the pressure to increase capacity will become even more intense. Capacity in the 800 and 900 MHz bands, where bandwidth is restricted, is already becoming a limiting factor. This paper attempts to address how the application of smart antenna systems has brought about improvements in call quality and increased capacity through reduced Interference in Mobile Communication. The smart antenna may be in a variety of ways to improve the performance of a communications system. Perhaps most importantly is its capability to cancel co-channel interference. It helps in improving the system performance by increasing the channel capacity, spectrum efficiency, extending range coverage, speech quality, enabling tighter reuse of frequencies within a cellular network and economically, feasible increased signal gain, greater, reduced multipath reflection. It has been argued that Smart antennas and the Algorithms to control them are vital to a high-capacity communication system development.

关键词： GSM signal quality Smart Antenna Carrier-to-Interference Ratio Co-Channel Interference

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Research on the Influence of Satellite signal Transmission Channel’s Non-Ideal Characteristics on the quality of Different Envelope signals

Research on the Influence of Satellite Signal Transmission C...

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第十三届中国卫星导航年会

作者： Qianqian Yang Chengyan He Zhigang Hu Zibin Han National Time Service Center Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Precise Positioning and Timing Technology Chinese Academy of Sciences Wuhan University

At present, most satellite navigation systems use constant envelope multiplexed signals, in order to reduce the non-linear influence of the power amplifier as much as possible. However, the actual signal transmission channel cannot be purely ideal. Various amplitude-frequency or phase-frequency distortions that may occur will affect the signal envelope characteristics and ranging performance, resulting in a certain difference between the actual signal received by the user and its theoretical design. Research has shown that the performance of the constant envelope signal after passing through the non-ideal channel may not be better than the corresponding non-constant envelope signal. In order to fully understand the specific effects of various non-ideal characteristics of the channel on the non-constant envelope signal and to judge under which non-ideal characteristics the non-constant envelope signal can show better performance, so as to provide new ideas for the design of navigation signals. This article first studies the non-ideal characteristics of the satellite signal transmission channel and establishes five channel distortion models. The BDS-3 B1 constant envelope and nonconstant envelope simulation ideal signals are used as the research signals of this article, use the software receiver to evaluate the signal quality of the ideal signal after the distortion model, and use the evaluation index S-curve zero-crossing deviation to express the signal’s ranging performance. Finally, the quantitative analysis and comparison of the ranging performance of different envelope signalsunder the influence of various distortions are realized. The results show that: Inaddition to amplitude ripple distortion, non-constant envelope signals show better ranging performance overall under the same distortion conditions. The research results of this paper have certain reference value for signal design and signal quality evaluation.

关键词： Navigation signal Transmission channel Non-ideal characteristics Constant envelope Non-constant envelope signal quality

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Influence of B1 code correlation loop for vector tracking structures under complicated environment

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Journal of Systems Engineering and Electronics 2019年第6期30卷 1053-1063页

作者： WANG Qian SHANG Feng DU Liming ZHOU Wenjia School of Electronic Engineering Xi’an University of Posts and Telecommunications Qingdao Huatong Intelligent Research Institute

The code tracking loop is a key component for user positioning. The pseudorange information of Bei Dou B1 signals has been fused and changed for vector tracking, so a correlation output model for complex scenarios is designed to prevent the propagation of error and valuate the signal performance. The relevant software and hardware factors that affect the output are analyzed.A single channel time-division multiplexing(TDM) method for multicorrelation data extraction is proposed. Statistical characteristics of the correlation output data for both vector and scalar structures are evaluated. Simulation results show that correlation outputs for both structures follow normal or Chi-squared distributions in normal conditions, and the Gamma distribution in harsh conditions. It is shown that a tracking model based on the multi-channel fusion hardly changes the probability distribution of the correlation output in the normal case, but it reduces the ranging error of the code loop, and hence the tracking ability of the code loop for weak signals is improved. Furthermore, vector tracking changes the pseudorange characteristics of channels anytime, and affects the mutual correlation outputs of the code loops in the abnormal case. This study provides a basis for the subsequent design of autonomous integrity algorithms for vector tracking.

关键词： vector tracking signal quality code correlation pseu dorange error scalar tracking correlation peak loss.

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