Detecting process mean shift in the presence of autocorrelation: a neural-network based monitoring scheme

The main purpose of this paper is twofold: (1) to present a neural-network based methodology for monitoring process shift in the presence of autocorrelation; and (2) to demonstrate the power, the effectiveness, and the adaptability of this approach. The proposed neural network uses the effective and efficient extended delta-bar-delta learning rule and can be trained with the powerful back-propagation algorithm. The comparative study on AR(1) processes shows that the performance of this neural-network based monitoring scheme is superior to that of SCC, X, EWMA, EWMAST and ARMAST control charts in most instances. Moreover, the network output can also provide information about the shift magnitude. The study of run length distributions suggests that further improvement on designing such neural networks is possible. The adaptability of the neural-network approach is demonstrated through the flexible design of the training data set. To further improve run length properties under various shift magnitudes, alternative control heuristics are proposed.     

A new query expansion method for document retrieval based on the inference of fuzzy rules

Abstract

Automatic query expansion based on user relevance feedback techniques can improve the performance of document retrieval systems. In this paper, we present a new query expansion method based on the inference of fuzzy rules and user relevance feedback techniques to deal with document retrieval. The proposed method uses membership functions and fuzzy rules to infer relevant degrees of expansion terms and puts the expansion terms with larger relevant degrees into the original user's query. Then, the system calculates the degree of similarity of each document with respect to the expanded user's query. The proposed method gets a higher average precision rate and a higher average recall rate than the existing methods for document retrieval.     

Using the method of conservative scalars for the calculation of thermal radiation of turbulent diffusion flame

Data on laser probing of laboratory flames are used to quantitatively estimate the contribution made by turbulent fluctuations of thermodynamic parameters to thermal radiation of hydrogen diffusion flame. The coefficients in the equation of radiation transfer are averaged directly by samplings of instantaneous values of temperature and concentration; this helps eliminate errors associated with the use of model distribution functions. The obtained results are used to verify the approximate method for the calculation of thermal radiation of flame, which is based on the assumptions of thermochemical equilibrium of combustion and normal distribution of the coefficient of mixture.     

产品图样和技术文件的标准化审查

标准化审查（以下简称标审）,是指：根据国家有关技术经济政策与现行技术标准和标准化的原理、方法、要求等,对产品的图样和技术文件（包括设计文件和工艺文件）所进行的技术性审查。１．标审的依据（１）《中华人民共和国标准化法》及其实施条例;（２）国家标准、行业标准、地方标准和企业标准,以及有关的国际标准和国外先进标准;（３）有关的技术经济政策、法规、规章文件;（４）顾客（合同情况下,通常写在合同中）和社会（通过市场调查等手段）对产品的要求。２．标审的目的（１）检查督促有关标准的贯彻执行情况;（２）了解并掌…     

数值计算结合试验测定模态阻尼法

任一种分布的激励必将引起多个模态的响应,试验中要激出单一模态振动是很难的,传统阻尼比估算方法所采用的信号处理手段不能有效分离叠加模态,以致测试阻尼比往往误差较大。从多自由度叠加法动响应分析入手,指出模态混叠现象是制约精确阻尼比测试的重要因素,在阻尼较大、刚度较低时模态更密集、叠加效应更显著,提出通过数值计算进行模态截断以实现"纯模态"提取的方案,推导了共振激励下试验与数值仿真结果中频响峰值谱线表达式,找出二者间的关系,用纯模态计算结果修正测试阻尼比。通过对4块不同板单元进行前8阶试验模态分析与数值计算参数修正,结合频响函数验证了修正阻尼比的数据可靠性,得出了不同结构、材料间阻尼比差异的部分规律。结果表明,模型试验对复合材料板的阻尼比识别准确性要低于钢板,其阻尼性能往往被低估且修正幅度较大,该方法为模态参数识别的进一步研究提供了思路。     

An approximate method for the calculation of heat and mass exchange between gas and a liquid film

Using integral relations between the velocity and enthalpy of gas, we develop an engineering method for the calculation of the local and average parameters of media and the heat and mass flux without using the empirical data about contact instruments.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 53, No. 2, pp. 191–198, August, 1987.     

Extraction of text lines and text blocks on document images based on statistical modeling

In this article, we developed a Bayesian model to characterize text line and text block structures on document images using the text word bounding boxes. We posed the extraction problem as finding the text lines and text blocks that maximize the Bayesian probability of the text lines and text blocks given the text word bounding boxes. In particular, we derived the so-called probabilistic linear displacement model (PLDM) to model the text line structures from text word bounding boxes. We also developed an augmented PLDM model to characterize the text block structures from text line bounding boxes. By systematically gathering statistics from a large population of document images, we are able to validate our models through experiments and determine the proper model parameters. We designed and implemented an iterative algorithm that used these probabilistic models to extract the text lines and text blocks. The quantitative performances of the algorithm in terms of the rates of miss, false, correct, splitting, merging, and spurious detections of the text lines and text blocks are reported. © 1996 John Wiley & Sons, Inc.     

A hybrid dynamic pre-emptive and competitive neural-network approach in solving the multi-objective dispatching problem for TFT-LCD manufacturing

This research addresses a hybrid dynamic pre-emptive and competitive neural-network approach in solving the multi-objective dispatching problem. It optimises three performance criteria simultaneously, namely: cycle time, slack time, and throughput. A case study is adopted to illustrate the performance of applying the methodology. Thin film transistor-liquid crystal display (TFT-LCD) is a high-technology industry, with a growing market. The manufacturing process is complex. It involves multi-products, sequence-dependent set-ups, random breakdowns, and multiple-objectives, with bias-weighted optimisation problems. To determine appropriate dispatching strategies, under various system conditions, is a non-trivial challenge to control the complex systems. There has been little research on these problems aimed at solving them simultaneously. This paper presents an event-triggered dynamic dispatching system that combines artificial intelligence methods to archive optimum dispatching strategies under diverse shop-floor conditions. Results show this system to be superior to previous researches.     

Model for heat exchange between a well-developed fluidized bed and a surface within the bed

A physical model for heat exchange between a fluidized bed and a surface in contact with it is proposed and discussed. The heat exchange is due to heat transfer by oscillating particles.     

The effect of document types and sizes on the scaling relationship between citations and co-authorship patterns in management journals

The aim of this paper is to explore the power-law relationship between citation-based performance (CBP) and co-authorship patterns for papers in management journals by analyzing its behavior according to the type of documents (articles and reviews) and the number of pages of documents. We analyzed 36,241 papers that received 239,172 citations. The scaling exponent of CBP for article papers was larger than for reviews. Citations to articles increased 2^1.67 or 3.18 times each time the number of article papers published in a year in management journals doubled. The citations to reviews increased 2^1.29 or 2.45 times each time the number of reviews published in a year in management journals doubled. The scaling exponent for the power-law relationship of citation-based performance according to number of pages of papers was 1.44 ± 0.05 for articles and 1.25 ± 0.05 for reviews. The citations to articles increased faster than citation to reviews. The scaling exponent for the power-law of citation-based performance to co-authored articles was higher than single-authored articles. For reviews the scaling exponent was the same for the relationship between citation based performance and the number of reviews. Citations increased faster in single authored reviews than co-authored reviews.     

Generalized method of pressure drop and tube length calculation with boiling and condensing refrigerants within the entire zone of saturation

A simple and universal method of pressure drop and horizontal tube length calculation with boiling and condensing refrigerants within the entire saturation zone ranging from critical point down to the lowest temperatures, is proposed. The method can be applied for the calculation ofevaporators and condensers operating in conventional and non-conventional refrigeration, air conditioning and heat pump system, as well as in similar cases. By introducing a two-phase flow factor, β, and a liquid/vapour gradient ratio, θ, the correlation given by Müller-Steinhagen and Heck can be rearranged to a siple dimensionless form which leads to a family of universal curves that enable any dry-saturated vapour flow gradient to be transformed into an actual two-phase flow gradient, or vice versa, at any temperature and liquid/vapour mixture quality within the entire saturation zone of refrigerants. Determination of θ is a key factor in the accuracy of the calculation. Appropriate correlations and diagrams for predicting τ are presented in terms of corresponding states principle. Some practical advice and numerical examples of evaporators and condensers calculation are given.     

Stress intensity factor calculation based on the work of external forces

The external forces method is a numerical method for K calculation based on the finite element method. It uses the work of the external forces W for the calculation of the energy release rate and is particularly advantageous when that forces are applied far from the crack front. The method was applied to a corner crack geometry with the objective of studying its accuracy. Good results were obtained for a wide range of virtual crack displacements (0.03% < Δa/a < 6%) considering 4 values of W along with a polynomial regression of order 3. For that choice of parameters the inaccuracy of K is mainly due to FEM errors. A great sensitivity of K to FEM errors was observed, however accurate values of K were obtained, with errors lower than 2 percent. So, the use of the external forces method for the calculation of K is recommended, considering its simplicity and accuracy. This revised version was published online in July 2006 with corrections to the Cover Date.     

Criteria and formulas for the calculation of the fluidization rate

An equation of motion is derived for individual particles in a fluidized bed of a monodisperse material in connection with the onset of fluidization. Dimensionless complexes have been derived on the basis of this equation and these are used to process the experimental data. A theoretical formula is derived.     

一种基于残周期正弦拟合的冲击峰值计算方法

针对半正弦冲击波形峰值幅度的计算,提出了一种基于残周期正弦曲线拟合的最小二乘计算方法,通过在脉冲测量波形中截取峰值附近近似于半正弦部分的峰值波形,使用残周期正弦曲线拟合方法计算获得冲击峰值幅度。它具有操作简捷易行、收敛性好的特点,并可以通过拟合残差有效值来判定拟合效果的优劣。该方法直接使用截取的峰值波形原始数据进行计算,不需要用滤波器对波形数据进行预处理,从而避免了冲击计量中常用的数字滤波给峰值计算结果带来的影响,可以获得更加客观准确的校准结果。通过在实际校准实验波形上的计算,并与以往计算方法进行了比较,验证了所述方法的有效性和切实可行性。     

螺栓与被连接件间轴向相对刚度的修正计算

螺栓连接结构的载荷分配比例和螺栓与被连接件间的轴向相对刚度密切相关。为了更准确地求解螺栓连接结构中螺栓与被连接件间的轴向相对刚度，基于被连接件垂直于螺栓轴的各受压层压应力均匀分布与非均匀分布形式下的轴向压缩变形量解析式，结合有限元仿真结果，提出了被连接件压缩变形体起始直径的修正公式及轴向压缩变形量的修正解析式。通过提取仿真应力值，对压应力理论修正方程、压应力仿真拟合方程进行积分计算。对比计算结果发现：用仿真拟合方程计算得到的被连接件压缩变形体轴向压缩变形量与用理论修正方程计算得到的变形量的误差小于2.5%，这说明用仿真拟合方程求解被连接件压缩变形体的轴向压缩变形量具有较高的精度。研究结果表明：修正起始直径与夹紧长度、螺栓头与螺母支承面直径呈线性关系。压应力非均匀分布下，用被连接件压缩变形体轴向压缩变形量的修正解析式求解螺栓与被连接件间轴向相对刚度时，误差小于2%，表明该修正解析式能够较为准确地计算螺栓与被连接件间的轴向相对刚度。在修正起始直径的基础上，基于被连接件各受压层压应力非均匀分布的轴向相对刚度计算结果比基于均匀分布的更准确。研究结果为理论研究和实际工程中准确分析螺栓的受力情况提供了一定参考。     

Microscopic calculation of the heat transfer between a granular structure and liquid3He

A recent formula for the heat transfer coefficient between ³He quasiparticles and phonons of a sintered metallic powder is evaluated using the phonon density of states of a microscopic model of a granular structure. The microscopic model describes a simple crystalline granular structure and contains extended modes only. When the dominant phonon wavelength is less than a typical grain size, possesses a low-temperature enhancement typical of a sintered metallic powder and over a limited range exhibits a linear variation with temperature.     

基于微分求积法及V-变换的大规模动力系统快速数值计算方法

针对大规模动力系统动态响应的数值计算,传统的微分求积法通常在时间域上逐步离散、整体求解,存在“维数灾”问题。在多级高阶时域微分求积法的基础上,提出了基于V-变换的大规模动力系统动态响应的快速数值计算方法。利用微分求积法的加权系数矩阵满足V-变换这一重要特性,将离散后的雅可比矩阵方程进行解耦分块,推导形成了多级分块递推计算方法。数值算例表明,即使采用相当于Newmark方法2s倍的步长,微分求积法的计算精度仍比Newmark方法要高出2~3个数量级。进一步对3个不同规模的算例系统进行了测试,结果表明：相对于传统的数值计算方法,多级分块递推计算方法可以获得较大的加速比,能够显著提高大规模动力系统动态响应的计算效率。