虚拟实验室的应用研究

虚拟实验室在现代教学活动中的作用越来越大,对培养学生的实际工作能力至关重要。本文通过虚拟实训室的建设和实训教学应用研究,已逐步推广到电子技术应用、仪表测量、计算机控制技术、集散控制系统(DCS)、化工操作等方面,提高了教学效果。     

How evolutionary algorithms are applied to statistical natural language processing

Statistical natural language processing (NLP) and evolutionary algorithms (EAs) are two very active areas of research which have been combined many times. In general, statistical models applied to deal with NLP tasks require designing specific algorithms to be trained and applied to process new texts. The development of such algorithms may be hard. This makes EAs attractive since they offer a general design, yet providing a high performance in particular conditions of application. In this article, we present a survey of many works which apply EAs to different NLP problems, including syntactic and semantic analysis, grammar induction, summaries and text generation, document clustering and machine translation. This review finishes extracting conclusions about which are the best suited problems or particular aspects within those problems to be solved with an evolutionary algorithm.     

On the use of different loss functions in statistical pattern recognition applied to machine translation

In pattern recognition, an elegant and powerful way to deal with classification problems is based on the minimisation of the classification risk. The risk function is defined in terms of loss functions that measure the penalty for wrong decisions. However, in practice a trivial loss function is usually adopted (the so-called 0–1 loss function) that do no make the most of this framework. This work is focused on the study of different loss functions, and specially on those loss functions that do not depend on the class proposed by the system. Loss functions of this kind have allowed us to theoretically explain heuristics that are successfully used with very complex pattern recognition problem, such as (statistical) machine translation. A comparative experimental work has also been carried out to compare different proposals of loss functions in the practical scenario of machine translation.     

Understanding indirect system use of junior employees in the context of healthcare

As digital natives, junior employees are believed to be highly tech-savvy and directly use enterprise system in daily work. However, prior literature has reported a considerable number of indirect system use by junior employees. This study aims to understand this seemly paradoxical phenomenon. We theorize indirect system use as a technology interaction behavior with delegation. Results of a survey among junior physicians show that quantitative overload, positional legitimacy power, and social legitimacy power are significant antecedents of their indirect system use. Moreover, social legitimacy power has a stronger influence than positional legitimacy power.     

Using mathematical expressions in a statistical language

Statistical models consist of mathematical expressions and algorithms. In a statistical system, such models are described in a statistical language. Therefore, a statistical language is useful if it can handle mathematical equations directly and connect them with algorithms seamlessly. This ability enables users to write and read programs intuitively and easily. The statistical language having this ability has been implemented in a statistical system Jasp using Java and MathML technologies.     

基于EPON技术的配电通信接入网的研究设计

近几年来,科学技术以及电力自动化系统的不断发展,对配电通信接入网的设计提出了更高的要求。配电自动化是智能电网建设的重要组成部分,配电通信接入网的性能以及安全性直接影响配电自动化通信的安全。本文针对EPON技术做一简单阐述,重点探讨基于EPON技术的配电通信接入网的设计方案,最后通过实例验证该方案的可行性。     

Understanding the human context in requirements elicitation

The human context within which a software system will operate is fundamental for its requirements. It may not appear to be very much related to the system, but it is very relevant in achieving its successful adoption. However, requirements engineers have usually a background in Software Engineering and are not trained to elicit this kind of information. This situation raises the need for analytical tools to deal with these features. These tools should enable collaborative work between requirements engineers, who use them in development, social practitioners, who provide the knowledge and processes underlying these tools, and the customers, who know the domain and intended application of the projects. The framework presented in this paper is based on the socio-psychological Activity Theory and its analysis of human contexts. It includes a repository of social properties and a process to perform this elicitation using it. The paper illustrates its application through a case study on the impact of a new system in the organization of a firm.     

Statistical analysis of cell directions in applied current experiments

A program has been developed to analyze cell directions sampled during the course of experiments in which uniform electrical currents are passed over cells grown in tissue culture. The program can test data sets for statistically significant orientation, i.e. clustering about a certain mean angle, and can also perform a pairs test between two data sets to determine whether there is a significant difference in orientation between them.     

电力系统维修的关键要点研究

采用先进的检测手段和分析诊断技术来检测设备状态,在任何时候都能使设备的运行状况将得到体现,这取决于设备的维修项目及维修时间合理安排,最大限度地降低维护成本,提高设备的可靠性,延长使用寿命.本文将探讨以上等问题.     

Software abstraction of elements of statistical strategy

This paper presents some general approaches to building software representations of statistical strategies. In statistics, strategy is the skilful management of data, probability models, experimental designs, and other statistical concepts. This paper addresses the representation of these concepts separately from the representation of the actions taken on them. The issue of having a credible visual interface with these representations is also raised.     

Exemplar-based statistical model for semantic parametric design of human body

This paper presents an exemplar-based method to provide intuitive way for users to generate 3D human body shape from semantic parameters. In our approach, human models and their semantic parameters are correlated as a single linear system of equations. When users input a new set of semantic parameters, a new 3D human body will be synthesized from the exemplar human bodies in the database. This approach involves simpler computation compared to non-linear methods while maintaining quality outputs. A semantic parametric design in interactive speed can be implemented easily. Furthermore, a new method is developed to quickly predict whether the parameter values is reasonable or not, with the training models in the human body database. The reconstructed human bodies in this way will all have the same topology (i.e., mesh connectivity), which facilitates the freeform design automation of human-centric products.     

Statistics with fuzzy data in statistical quality control

Statistical quality control (SQC) is an important field where both theory of probability and theory of fuzzy sets may be used. In the paper we give a short overview of basic problems of SQC that have been solved using both these theories simultaneously. Some new results on the applications of fuzzy sets in SQC are presented in details. We also present problems which are still open, and whose solution should definitely increase the applicability of fuzzy sets in quality control.     

Genetic evolving ant direction particle swarm optimization algorithm for optimal power flow with non-smooth cost functions and statistical analysis

This paper presents an evolving ant direction particle swarm optimization algorithm for solving the optimal power flow problem with non-smooth and non-convex generator cost characteristics. In this method, ant colony search is used to find a suitable velocity updating operator for particle swarm optimization and the ant colony parameters are evolved using genetic algorithm approach. To update the velocities for particle swarm optimization, five velocity updating operators are used in this method. The power flow problem is solved by the Newton–Raphson method. The feasibility of the proposed method was tested on IEEE 30-bus, IEEE 39-bus and IEEE-57 bus systems with three different objective functions. Several cases were investigated to test and validate the effectiveness of the proposed method in finding the optimal solution. Simulation results prove that the proposed method provides better results compared to classical particle swarm optimization and other methods recently reported in the literature. An innovative statistical analysis based on central tendency measures and dispersion measures was carried out on the bus voltage profiles and voltage stability indices.     

Low power DCVSL circuits employing AC power supply

In view of changing the type of energy conversion in CMOS circuits, this paper investigates low power CMOS circuit design, which adopts a gradually changing power clock. First, we discuss the algebraic expressions and the corresponding properties of clocked power signals. Then the design procedure is summed up for converting complementary CMOS logic gates employing DC power to the power-clocked CMOS gates employing AC power. On this basis, the design of differential cas-code voltage switch logic (DCVSL) circuits employing AC power clocks is proposed. The PSPICE simulations using a sinusoidal power-clock demonstrate that the designed power-clocked DCVSL circuit has a correct logic function and low power characteristics. Finally, an interface circuit to convert clocked signals into the standard logic levels of a CMOS circuit is proposed, and its validity is verified by computer simulations.     

隧道大型轴流风机变频技术的应用研究

依托秦岭终南山隧道工程,对隧道的基本情况进行了统计,并依据统计数据详细计算了隧道的通风需求,然后在此基础上对变频器进行了设计,最终得出节能环保的通风运行方案。结果表明：大型轴流风机加入变频技术后,隧道通风运营中的节能效果明显提高。     

Decision making on the sole basis of statistical likelihood

This paper presents a new axiomatic decision theory for choice under uncertainty. Unlike Bayesian decision theory where uncertainty is represented by a probability function, in our theory, uncertainty is given in the form of a likelihood function extracted from statistical evidence. The likelihood principle in statistics stipulates that likelihood functions encode all relevant information obtainable from experimental data. In particular, we do not assume any knowledge of prior probabilities. Consequently, a Bayesian conversion of likelihoods to posterior probabilities is not possible in our setting. We make an assumption that defines the likelihood of a set of hypotheses as the maximum likelihood over the elements of the set. We justify an axiomatic system similar to that used by von Neumann and Morgenstern for choice under risk. Our main result is a representation theorem using the new concept of binary utility. We also discuss how ambiguity attitudes are handled. Applied to the statistical inference problem, our theory suggests a novel solution. The results in this paper could be useful for probabilistic model selection.     

Internet mapping for dissemination of statistical information

City and regional administrations find increasing interest in providing mapping services to their customers: citizens, businesses, non-governmental organizations, etc. The paper discusses possible architectures of implementing such services on the Internet, and then describes our own system, Descartes, in more detail. Descartes can be used in client–server mode, where the interactive client interface can be downloaded as a Java applet. Descartes is particularly suited for Web-based analysis and publication of geo-referenced statistical data. The functionality and user interface of Descartes is illustrated by some example applications of the cities of Bonn and Tilburg and of the UK Census of Population.     

基于模糊神经和局部统计的变压器故障研究

为了实现电网运行状态的在线监测和故障诊断隔离,提出了基于模糊神经模型和局部统计方法的故障诊断隔离机制。首先在分析电力变压器故障的基础上,利用模糊神经网络建立无故障状态时电力变压器的温度模型,得到模糊神经模型和实际电力变压器输出的温度偏差,然后结合优化的全局检验和最小最大检验的局部统计方法计算对应故障诊断和隔离指标。当其超过设定的故障阈值时,该评估系统可早期发现故障和启动警报,并根据具体参数变化将故障定位在变压器具体元件。仿真试验表明,提出的故障诊断和隔离方法在实际系统中表现出优越的性能,能够提前发现故障原因,维护电网高效运营,具有重要的理论意义和应用价值。     

大功率白光LED恒流驱动芯片的设计研究

介绍一种串联饱和型白光LED照明恒流驱动芯片的设计,电路包括带隙基准电压源、反馈电路、电流传感取样电路、LDO电路、大功率驱动电路五部分。