Papers by Keyword: Uncertainty

Abstract: According to trade development characteristics of port city between China and North Korea, the uncertain factors in economic and trade development with North Korea are analyzed in this article. Taking Ji'an city of Jilin as an example, the article analyzes the problems about city economy, urban land use, tourism development during the port construction process in Ji'an city, provides the guiding principles as "flexible plan" for construction of port city facing to North Korea, namely establishing the "321" flexible industrial layout mode, establishing elastic urban land development model with "symbiosis" philosophy, establishing "flexible space structure" of border feature land and proposing the development idea of three principles, two Expansions, one Integration for tour features.

Abstract: Based on coordinate measuring machine (CMM) the given part is measured in any orientation, and then the least square evaluation mathematical model of plane orientation tolerance is established. What’s more, the uncertainty evaluation method of orientation error is proposed according to the uncertainty theory of new geometrical product specification (GPS). The face-to-face angularity is taken as the example to present the effectiveness of the proposed uncertainty evaluation method. The result shows that the uncertainty evaluation method not only meets the requirements of new GPS standard, but also ensures the integrity of the flatness inspection results. As a result, the accuracy of the workpiece inspection can be improved.

Abstract: In order to research the uniformity and volatility of thermostatic bath used on electronic thermometer verification, a method based on thermostat technical performance specifications is presented. Including the introduction of calibration device, the choice of standard device and experiment method. In the end the uncertainty analysis on the measurement of thermostatic bath uniformity and volatility is made. Experiment results show that the uniformity and volatility of this thermostatic bath are 0.0091°C and 0.0087°C/10min with the measurement uncertainty of 0.018°C, The results meet the requirements of electronic thermometer verification. It provides guarantee for the next electronic thermometer verification.

Abstract: The presence of water in the engine lubrication system is supposed to be a significant factor, which causes engine corrosion. Atomic spectrometry method and method for water content determination were applied for the detection of corrosion. Rotating disc electrode optical emission spectrometry (RD OES) is a method used to determine the concentration of 21 chemical elements in used lubricating oil in 30 seconds. In the used oil the concentration of Fe, Cu and Sn was monitored because these elements are indicators of bearing wear. The elements were analyzed using Conostan S-21 organo metallic calibration standards. The precision of the method was verified by calculating RSD for n = 3, the values of which are for Fe, Cu and Sn less than 7 %. Accuracy of measurement was verified by measuring standard reference material NIST 1084a. Karl Fischer volumetric method was used for the determination of water content in used lubricating oils with precision less than 1 %. The obtained reference material 34849 HYDRANAL-Water Standard 10.0, which is traceable to NIST SRM 2890 for determination of water content by Karl Fischer method, was analyzed for accuracy purposes.

Abstract: According to the impact of the wind power prediction uncertainty on the power system reserve capacity, the idea of scenario is introduced to the stochastic programming model. The method of scenario is used to simulate the uncertainty model of the wind power generation, load and the conventional units. The scenario-reduction methodology is combined to reduce the large scenario set to a simpler one, then the probability statistics on these scenarios is given in order to obtain the probability density of the system power difference, and the expected energy not supplied (EENS) and expected wind waste risk (EWWR) are presented. The reserve capacity is determined by the two aspects, which are the reliability shown by EENS and EWWR, and the economy of reserve capacity cost. Finally, simulations on a ten-unit system are given to demonstrate the method is effective to reduce the cost of reserve and the abandoned wind power in the context of system reliability.

Abstract: The current method is presented to calibrate the constant of Helmholtz coils. Two measurement methods of magnetic field strength are proposed and compared. In order to improve the accuracy, the influence of geomagnetic field is eliminated by changing direction of the magnetic field of Helmholtz coils. When the magnetic field strength is measured by Guassmeter, the calibration uncertainty is 0.12% (k=2). When the magnetic field strength is measured by Fluxmeter and search coil, the calibration uncertainty is 0.30% (k=2).

Abstract: Large-scale comparators of over 30m range are traceable devices of dimensional measurement in advance large-scale manufacture domain. High precision large-scale laser comparator is an open air laser interferometric measurement device, mainly made up of length measurement system, guiding rail system and control system. The length measurement system use laser interference system to get displacements, the main source of the measurement uncertainty of displacements comes from the air temperature measurement uncertainty. This paper put forward a novel air temperature compensation method by weighting-section compensation in the large-scale laser comparator optical path. The method can improve the length measurement uncertainty of large-scale laser comparator to 2×10^-8 level with changing the hardware of air temperature measurement system.

Abstract: The article deals mainly with the risk analysis and uncertainty of a risk of renewable resources. It also mentions the importance of managing the risks associated with the uncertainty of a risk of renewable resources. Specifically, in the paper addressed the relationship between risk and uncertainty, their interdependence, and the possibilities of how to work with uncertainty at risk. The distinguishing factor between the risk and the uncertainty is that risk is seen as a measurable property and has a place in the calculation of probability, while uncertainty does not have such property. The paper deals with an approach to this situation.

Abstract: Uncertainties elevator group control systems are analyzed first in this paper according to the fuzzy control theory and characteristics of the elevator group control system. Then, simulation model of elevator group control system is built using fuzzy inference system with Matlab. Operation of elevator group control system based on fuzzy control system is shown by simulation.

Abstract: Many uncertain factors influence the assessment of voltage sag frequency (VSF), such as system operation modes, the fault rates of components and fault locations. In existing methods these factors are considered constant resulting in reasonless results. In this study, the uncertain property of fault location, system operation mode and failure rate of component are integrated to assess the VSF for the first time. The maximum entropy principle, typical operation modes and time-varying rate are used for characterizing the uncertainty of these factors. The assessing method and approaches are presented. Three cases considered different conditions are simulated on IEEE-30 standard testing system. The proposed method compared with Monte Carlo Simulation has been shown that it is reasonable and accurate and with good academic value and practical foreground.