Papers by Keyword: Bias

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Authors: Zai Fang Zhang, Xiao Song Wu, Rui Miao, Bei Xin Xia
Abstract: Process capability index (PCI) has been widely applied in manufacturing industry as an effective management tool for quality evaluation and improvement, whose calculation in most existing research work is premised on the assumption that there exists no bias. In this paper, the bias of gauge which exerts an effect on the calculation of PCI is indicated inevitable. The influence on PCI caused by the bias is analyzed by constructing a comparative ratio R between the empirical process capability index and the PCI. A confidence interval estimation method is proposed to solve the underestimation problem of PCI.
Authors: Xiang Xiang Luo, Zhao Yang Guo, Zhi Liang Zhao, Feng Jie Xue, Xin An Wang
Abstract: Recently, there is a growing trend to investigate wide dynamic range compression technique with the development of hearing aids. However, existing methods used to enhance expected speech as well as the background noise and classical linear compression can’t achieve the requirements of hearing impaired individuals’ reaction to the loudness compensation flexibly. To cope with the problems, this paper proposes a new approach to suppress the enhanced background noise and to dismiss abnormal sound caused by severe jittering from high frequency signal. What’s more, a scheme of curve compression is introduced to improve the loudness amplifying flexibility instead of conventional linear compression. Both the theoretical simulation and testing on cellphone hearing aid APP based on android system prove the proposed method can improve the performance of speech enhancement and provide more choices to strength sound with the curve compression ratio.
Authors: Song Li, Xiao Feng He, Mei Ping Wu, Xiao Ping Hu
Abstract: In order to decrease the temperature error of MEMS gyroscopes, a mitigation method based on gyroscope array was proposed. Angular rate of MEMS gyroscope fluctuates dramatically with the change of gyro temperature when gyroscope starts up. The temperature characteristic error of MEMS gyroscope has become one of the major errors in the practical application. A mitigation method for temperature error was presented based on MEMS gyroscope array utilizing high correlation of temperature errors in the same batch of MEMS gyroscopes. This method was designed to improve environmental adaptability and shorten the startup time of MEMS based inertial measurement unit. Experimental results showed that the method was feasible and effective.
Authors: Rong Bin Hu, Xiang Cai
Abstract: In this paper, a novel 4-bit ADC is presented. The ADC adopts interpolated flash architecture with eight preamplifiers followed by fifteen latches. The ECL technique is used in the design of the ADC. Because of the novel design techniques adopted in the ADC, the conversion rate is very fast, up to 10Gsps, which has been proved by the stimulation results.
Authors: Rong Bin Hu, Xiang Cai, Xiao Ying Zhang
Abstract: In this paper, a novel BiCMOS current steering bandgap is presented, which includes reference core, start-up circuit, and output circuit, of which the reference core is used to produce the temperature-stable current, the start-up to start up the reference core when powered on, and the output circuit to proportionally transport the reference current to other cells on the same chip. Compared to the traditional voltage-mode bandgap reference, because of the adoption of the current-steering mode, the reference proposed in this paper, has the merits of being immune to variation of the power supply, minimum transport consumption, better matches, temperature stability, smaller area, auto-startup, and so on, which are specially needed in AD/DA application. The simulation shows that the proposed current-mode reference circuit has full temperature range coefficient of 8.9ppm, which is better than that of the traditional voltage-and current-mode reference circuits.
Authors: Hai Ping Huang, Pin Wang
Abstract: According to extensive quantity of public and factual data, this essay does tests on BIAS and W&R expert system of stock-market trading software in simulation experiment method, and compares their strength and weakness in the respect of mathematical statistics theory and Management objects, winning rate, annual return rate and net profit rate. The tests show that BIAS expert system is 2.58 times as good as W&R expert system in the items of annual return rate and net profit rate, 0.26 times in the item of the total number of trading. As a whole, BIAS expert system is superior to W&R expert system.
Authors: Guo Feng Sun
Abstract: Transformer inrush current generated has been plagued by engineering and technical personnel, is also a hot topic in the industry. Electro slag furnace is a common metallurgical industry furnace, used in the metal crystal more closely requirements, performance requirements and a variety of high quality roll alloys, high temperature alloys, nonferrous alloys. Electro slag furnace transformer is the core component, have a great no-load closing inrush current protection trip often makes itself affect the product quality and production efficiency or to expand on a power trip protection range. In order to suppress inrush current, with the primary winding series resistance speed-load closing the attenuation of inrush current, inrush current generated from the theoretical reasons to be discussed and a simple series resistance deduce the resistance of this method. Theoretical basis for comparison with other methods are not subject to a number of objective factors sufficient interference, the results demonstrate the practical application of this method is simple and inrush current suppression effect is very significant. Thus, the series resistance ESR furnace transformer inrush current suppression is a method of high cost.
Authors: Zhuo Shi Chen, Xiao Ming Yuan, Shang Jiu Meng
Abstract: The main causes of the ground motion blind prediction bias are the variability of the adopted program, the shear-wave velocity of the site, and the soil nonlinear dynamic parameters. By considering the variability of shear-wave velocity and the dynamic parameters, this essay used LSSRLI-1 Codes and Mw6.0 seismic record of Parkfield earthquake to calculate ground responses of 9 different conditions at Turkey Flat site. The authors believe that the variability of shear-wave velocity caused the dominant impact to the blind prediction of this shallow stiff-soil site. That impact is much greater than that of the dynamic parameters. LSSRLI-1 program may either underestimate the ground response of the shallow stiff-soil site or may overestimate it, so we should combine the specific site conditions and a large amounts of data to do the further analysis.
Authors: Carmen Simion
Abstract: Product and process conformance are determined by measurements that are taken by a measurement system. A clear understanding of the results of any measurement system requires an understanding of the possible errors within this system. Measurement system errors can be classified into two categories: accuracy and precision. The accuracy of a measurement system is usually broken into three components: bias, linearity and stability and the precision into repeatability and reproducibility. There are a number of procedures which are used, in the automotive and other industries to assess these statistical properties of any measurement system. Usually, companies use repeatability & reproducibility procedures but, according to a measurement systems analysis study, these may not be enough for a company that wants to meet current worldwide quality system standards. Lack of measurement equipment bias and linearity generally is not as predominant error as repeatability and reproducibility, nevertheless, it should be identified because each person that have direct responsibility for measurement evaluation, selection, and control must hand on experience in how to produce a bias and linearity study. A bias study examines the difference between the observed average of the measurements and a reference value. It answers the question “How accurate is my measurement equipment when compared to a master value ?”. A linearity study tells one how accurate the measurements are through the expected range of the measurements. It answers the question “Does my measurement equipment have the same accuracy for all sizes of objects being measured ?”. Determining the bias and linearity of the measuring equipments and understanding their impact on the measured values will contribute to the effectiveness of the measurement system. In this context, conception and method of bias and linearity analysis of measurement systems are introduced in this paper followed by a real world application done in a major local automotive company. The analysis had ensured consistency of measurements and provided evidence that the measurement system is functioning properly. Minitab software was used to study bias and linearity of the analyzed measurement system.
Authors: Si Yuan Frank Yang
Abstract: Measurement systems play important roles in producing consistent, high quality products in manufacturing industries. An important requirement for a measurement system is the consistency or stability of its measurement results. The measurement bias needs to be checked periodically in production to decide whether the measurement system needs to be recalibrated timely to maintain the consistency. A very popular conventional method of statistical bias test recommended by ISO/TS16949 for manufacturing industries has been reviewed. Its flaws and problems are pointed out and illustrated with special examples. A new method of engineering bias test and its equivalent accuracy test have been proposed to correct the problems of the conventional statistical bias test.
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