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Maurizio Caciotta, Sabino Giarnetti, Fabio Leccese
HYBRID NEURAL NETWORK SYSTEM FOR ELECTRIC LOAD FORECASTING OF TELECOMUNICATION STATION

This paper describes a neural network system for power electric load forecasting of telecommunication station. Getting an accuracy useful for contractual purpose a separately daily forecast of both main load and its oscillation is proposed.
For the mean daily forecast we used a three layers multi-layer perceptron (MLP), while to the oscillation forecasting we realized a system composed by a MLP and a self organizing map (SOM): the typology information obtained by the SOM unsupervised algorithm has been utilized as binary code in MLP input.
The proposed system with hourly power load data of a big telecommunication operator has been tested.
The total forecast has been obtained combining the two components. The forecasting accuracy for a whole year test data is around 2%. Some problem exists in the forecasted load of summer time.

Petr Ježdík, Jirí Novák
CAR’S IGNITION SYSTEM DIAGNOSTICS USING CONTINUOUS WAVELET TRANSFORM

The paper describes an unusual approach to diagnose standard ignition subsystem of fuel engines. All the information about real state conditions of the ignition coils and sparks is taken from simple measurement of power consumption transient of the electric control systems of engine. The transient is processed by continuous wavelet transformation (CWT). Result of the CWT is used for a classifier. Classifier is supposed to work in learning and diagnostic modes. The main output of the classifier is two disjoint states meaning correct and incorrect functional work of the engine ignition system. The described method is going to be used as a part of standard information equipment of vehicles. The method could bring saving the costs for automobile manufacturer.

Ignacio Lira, Dieter Grientschnig
BAYESIAN ANALYSIS OF A CALIBRATION MODEL

A Bayesian analysis of a calibration model was presented in Metrologia, 43 (2006) S167-S177, wherein two approaches were considered to obtain the probability density function associated with the measurand. In one of them, Bayes' theorem was applied directly to an input quantity for which measurement data were available. In the other approach, that same input quantity was expressed in terms of the measurand and the other input quantities. Since the forms of the likelihood function used in each approach were not the same, different prior functions were needed. In this paper we show that both approaches produce the same final results if the prior function to be used in the second approach is derived from that applicable to the first approach. By following this procedure, both prior functions are assured to encode the same initial information.

Andy Robinson, Andy Knott
UK TORQUE INTERCOMPARISON - 2007

This paper gives details of a round robin torque comparison involving the National Physical Laboratory (NPL) and nine other UK laboratories. The comparison covered two ranges: 20 N·m to 100 N·m and 200 N·m to 1 kN·m. The work was an effective way of disseminating the unit of torque to industry via the UK's new national torque standard, giving assurance to laboratories and customers and identifying areas for possible improvement.

Takashi Yamamoto, Masayuki Yamamoto, Kensuke Miyahara, Tatsuya Ishibashi
INFLUENCING PARAMETERS OF EQUIVALENT INDENTATION TEST

A newly developed hardness test based on equivalent indentation depth is currently expected to be the only hardness test method that enables seamless evaluations of hardness across different hardness scales in all load ranges from nanoscopic to macroscopic in an industrial friendly manner because the new method is free from the shortcomings of the instrumented indentation method, which requires calibration of tester frame compliance and detection of true specimen surface. However, as it is still in the early days of application, extensive data have yet to be accumulated concerning the equivalent indentation test. In this report, we discuss some major factors that can influence equivalent indentation depth, including the geometrical shape of the indenter used and the load ratio "r" (preliminary-to-total test force ratio).
As a result, it is found that the results of the equivalent indentation test using a pyramidal or conical diamond indenter are mutually convertible, and that the difference in equivalent indentation depth among Vickers, Berkovich, and Modified Berkovich indenters, which are probably the most popular indenters for the test, is as small as around ±1%. From our experiments, it is also confirmed that the equivalent indentation test is less susceptible to indenter tip wear than the instrumented indentation test.
Understandably, equivalent indentation depth is influenced by load ratio r, but the conversion formula developed by introducing an appropriate model into load curves is found to be effective for mutual conversions of the values of equivalent indentation depth at different load ratios for a practical range of applications.

Takashi Yamamoto, Masayuki Yamamoto, Kensuke Miyahara
ACCURACY OF STANDARD BLOCKS FOR HARDNESS AND UNCERTAINTY OF HARDNESS

The authors numerically discuss the accuracy of the hardness values of standard hardness blocks by evaluating the uniformity of hardness blocks and the resolution of hardness values according to test method. As a result of reviewing the results of this evaluation and the reasonability of the currently proposed method for evaluating the uncertainty of hardness values, it is revealed that the variance of hardness values of popular standard blocks for hardness - Rockwell and Vickers - is extremely small (σ ≤ 0.05 HRC, including the variance attributable to the tester). It is also found that the depth-measuring Rockwell test method shows higher resolution of hardness values than the Vickers test method using microscopic measurements.
Regarding the uncertainty of hardness, it is technically impossible to have discussions on the accuracy of uncertainty. Prior to discussing the uncertainty of hardness testing, we believe more efforts should be directed to studying ways to improve the accuracy and reliability of the testing method itself.

Christian Schlegel, Michael Gläser, Frank Schlolz, Gabriela Bethke, Michael Mecke
DETERMINATION OF THE ATOMIC MASS CONSTANT BY ION ACCUMULATION

An experiment for the direct measurement of the atomic mass constant was performed by accumulating ions from an ion beam up to a weighable mass. The aim of this experiment was to develop an alternative approach for the redefinition of the SI unit kilogram. In a recent experiment a mass of about 300 mg bismuth was accumulated and the atomic mass unit could be determined with a relative uncertainty better than 1.0 × 10-4.

Stephanie Enz
ASSESSMENT OF THE APPLICABILITY OF THE WEIGHT VECTOR THEORY FOR CORIOLIS FLOWMETERS

The weight vector theory for Coriolis flow meters has been the subject of research presented by Hemp and co-workers in various articles. The underlying theory may not be easily understood. This paper explains the application of the weight vector theory for Coriolis flowmeters. The theory is applied to simple theoretical meter configurations consisting of a single straight pipe. The application of the weight vector approach is of relevance when investigating velocity profile effects, e.g., in Coriolis flow meters. Promising results have been found in recent literature showing the vulnerability of straight pipe Coriolis flowmeter configurations to velocity profile effects. The application of the weight vector theory is shown to be either limited to the investigation of few parameters or employs unrealistic boundary conditions and lacks comparative studies, making a more comprehensive study desirable. The usefulness of the weight vector theory to predict velocity profile effects for bended tube is not apparent from today's state-of-the-art literature, but of great interest for flowmeter manufacturers since bended tubes designs are frequently used in today's Coriolis flowmeters.

Kyu-Tae Kim, Kwang-Min Yu
A NEW METHOD FOR INSULATION RESISTANCE MEASUREMENT AT LOW VOLTAGE LEVEL USING CHANGE OF EFFECTIVE RESISTANCE

Test of insulation resistance is pre-requisite for leakage effect evaluation in many electrical measurements. Especially high resistance measurement at low working voltage is often required for evaluation of high precision measurement system. The high resistance measurement at low voltage level with portable hand-set is a challenging task. Here we suggest a simple and convenient method to measure the insulation resistance of up to 10 TΩ order using the principle that effective resistance changes when insulation resistor under test is connected to a reference resistor. A prototype demonstration shows 10 % accuracy level can be easily achieved for 10 TΩ measurement with 10 V test voltage.

Dan Sporea, Adelina Sporea, Constantin Oproiu, Rodica Georgescu, Ion Vata
MEASUREMENT OF RADIATION EFFECTS ON ACTIVE AND PASSIVE OPTICAL FIBER COMPONENTS

The present contribution is focused on the measurement of the degradation induced in the case of two splitters and two attenuators used in optical fiber communication systems, under gamma and neutron irradiation. The measurements were carried out at specific wavelengths (λ = 1310 nm and λ = 1550 nm) or over a spectral band (λ = 1510 - 1620 nm), in order to evaluate the wavelength dependence of the phenomena. These components were also tested as it concerns the changes of the polarization state of optical radiation they guide. A second investigation was performed on the degradation of the operational parameters for a laser diode driving circuit and a Peltier TEC (thermoelectric cooler), under gamma-ray, neutron and electron beam irradiation. No significant changes were noticed in the spectral transmission of the two passive components, but the degradation of the light polarization parameters was a significant one under gamma-ray irradiation. In the case of the laser diode drivers a drop of 80 % of the laser diode optical power and the embedded photodiode responsivity was observed under gamma-ray and neutron irradiation.

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