In this paper, a robust online approach based on wavelet transform and matrix pencil (WTMP) is proposed to extract the dominant oscillation mode and parameters (frequency, damping, and mode shape) of ...a power system from wide-area measurements. For accurate and robust extraction of parameters, WTMP is verified as an effective identification algorithm for output-only modal analysis. First, singular value decomposition (SVD) is used to reduce the covariance signals obtained by natural excitation technique. Second, the orders and range of the corresponding frequency are determined by SVD from positive power spectrum matrix. Finally, the modal parameters are extracted from each mode of reduced signals using the matrix pencil algorithm in different frequency ranges. Compared with the original algorithm, the advantage of the proposed method is that it reduces computation data size and can extract mode shape. The effectiveness of the scheme, which is used for accurate extraction of the dominant oscillation mode and its parameters, is thoroughly studied and verified using the response signal data generated from 4-generator 2-area and 16-generator 5-area test systems.
State estimation is a major tool in the modern energy management systems and therefore requires well-designed measurement systems. In this paper potential applications of singular value decomposition ...on designing measurement systems are presented. It is shown that the classical problems of optimal measurement placement can be solved in a unified way by taking advantage of the decomposition properties. Furthermore, the paper also proposes the use of principal component analysis to evaluate the existing measurement systems. This analysis indicates which state variables have the worst accuracy and therefore the most effective buses to place measurements. A case study of measurement system evaluation and reinforcement with IEEE 14-bus system is presented.
Variographic characterisation has been shown to be a powerful tool to assess the performance of process measurement systems, using existing process data. Variogram interpretation enables ...decomposition of variabilities stemming from the process and measurement system, respectively, allowing to determine if measurements are able to describe the true process variability with sufficient resolution. This study evaluated 14 critical sampling locations, covering a total of 34 separate measurement systems, along the full processing value chain at Luossavaara Kiirunavaara limited company (LKAB), Sweden. A majority of the variograms show low sill levels, indicating that many sub-processes are well controlled. Many also show low nugget effect, indicating satisfactory measurement systems. However, some notable exceptions were observed, pointing to systems in the need of improvement. Even if some of these were previously recognized internally at LKAB, the use of variographic characterisation provide objective and numerical evidence of measurement system performance. The study also showed some unexpected results, for example that slurry shark-fin and spear sampling show acceptable variogram characteristics for the present materials, despite the associated incorrect sampling errors. On the other hand, the results support previous conclusions indicating that manual sampling and cross belt hammer samplers are leading to unacceptably large sampling errors and should be abandoned. Such specific findings underline the strength of comprehensive empirical studies. Based on the present compilation of results, it is possible to conduct rational enquiry of all evaluated measurement systems, enabling objective prioritization of where improvement efforts will have the largest cost–benefit effect.
Bicycling is a potential way to improve sustainable urban transportation system. However, the evaluation methods and metrics for bicycle ride quality and slow traffic pavement condition are still in ...the preliminary stages. The traditional bicycling vibration measurement used instrumented probe bicycle (IPB), which contains several independent devices and obtains scattering data. This method cannot show the detailed pavement condition. A technical challenge for monitoring real-time bicycling comfort and obtain the pavement condition in detail is to combine the intelligent transportation system (ITS) with bicycles. In this study, two schemes have been proposed to acquire the vibration data based on portable terminal measurement systems. Scheme (1) was based on the IPB using GPS, accelerometers, and sport cameras. The microcontroller was used to integrate several modules to develop scheme (2). Wavelet analysis was introduced to analyse random signal data. Then the pavement condition can be reflected in detail by vibration response. Data derived from the proposed system can be successfully applied to promote the use of bicycles as a reflecting tool for the pavement surface conditions. This method can provide a reference database for pavements’ surface maintenance and for cyclists to choose cycling routes.
Abstract Non-adherence to a drug therapy is often the reason for not achieving the therapeutic goals in patients. Measuring drug adherence is an important intervention to understand patients’ ...adherence patterns and behavior as well as to provide supportive measures to enhance the patient adherence to a prescribed drug therapy. A variety of different adherence measurement systems (AMS) exist that have been proven valid even though there is not one single AMS considered to be a gold standard. Some AMS allow through interactions with the physician or pharmacist and the patient to initiate corrective interventions, mainly in the form of alert and reminder systems. When applied to patients with several morbidities, co-morbidities and disabilities, appropriate AMS still remain a challenge.
Portable emission measurement systems (PEMS) 1 are used by the US Environmental Protection Agency (EPA) to measure gaseous and particulate matter mass emissions from vehicles in normal, in-use, ...on-the-road, and “real-world” operations to support many of its programs. These programs include vehicle modeling, emissions compliance, regulatory development, emissions inventory development, and investigations of the effects of real, in-use driving conditions on NOx, CO₂, and other regulated pollutants.
This article discusses EPA’s analytical methodology for evaluating light-duty vehicle energy and EU Real Driving Emissions (RDE). A simple, data-driven model was developed and validated using measured PEMS emissions test data. The work also included application of the EU RDE procedures and comparison to the PEMS test methodologies and FTP and other chassis dynamometer test data used by EPA for characterizing in-use light– and heavy-duty vehicle emissions. This work was conducted as part of EPA’s participation in the development of UNECE Global Technical Regulations and also supports EPA mobile source emission inventory development. This article discusses the real-world emissions of light-duty vehicles with 12V Start-Stop technology and light-duty vehicles using both gasoline and diesel fuels.
The article presents verification of robustness of contactless method based on 2D image camera, which is used to measure catenary contact wire position in changeable ambient lighting conditions. ...Robustness in changeable lighting conditions is ensured through the combination of advanced image processing for background information removal and the algorithm of error correction. This algorithm detects incorrect images and substitutes information from these images with proper measurement data obtained from correct images which precede and follow the incorrect one. The paper presents and discusses the processing algorithms used, as well as shows examples of measurement results obtained on a full scale laboratory stand.
During industrial forging of hot metallic shells, it is necessary to regularly measure the dimensions of the parts, especially the inner and outer diameters and the thickness of the walls. A forging ...sequence lasts 2 h or more during which the diameter of the shell is regularly measured in order to decide when to stop the forging process. For better working conditions, for the safety of the blacksmiths, and for a faster and more accurate measurement, we have developed a novel system based on two commercially available time of flight laser scanners for the measurement of the diameters of hot cylindrical metallic shells during the forging process. The advantages of using laser scanners are that they can be placed very far from the hot shell, more than 15 m, while at the same time giving an accurate point cloud from which three-dimensional views of the shell can be reconstructed and diameter measurements done. Moreover, more accurate measurement is achieved in less time with the laser system than with the conventional method using a large ruler. The system has been successfully used to measure the diameters of hot cylindrical metallic shells.
In this paper, we report on the advance and application of our DAICOX system conceived for
the automated and transparent design of integrated intelligent multi-sensor measurement
applications. The ...current implementation allows the front to back design from raw sensory
data to decision making. In particular, novelty or One-Class Classification (OCC) methods,
improved assessment functionality, and automated design of feature computation by
multi-objective optimization techniques to complete the processing chain complement the
system. Two representative applications, i. e., basic food analysis and magnetic
localization, have been selected as case studies with existing manual solutions to
demonstrate and assess the applicability of the conceived architecture and its
implementation. DAICOX reduced the design time by 98.62%, while increasing the
recognition rate by 5.21% in the first case study and 0.71% in the second
case study. The optimized solution can now be deployed to a run time system. In future work,
extension of the method portfolio, self-x functionality, and public-domain availability are
aspired.
Validation of instrumental evaluation methods or measurement systems plays an important role in both pharmaceutical and cosmetic research and development. In practice, it is suggested that validation ...should be performed according to performance characteristics as described in the United States Pharmacopedia and National Formulary (USP/NF, 2000) for analytical methods validation. A validated method or measurement system is expected to achieve a certain degree of accuracy and reliability. However, it is a concern whether the test results obtained are repeatable (with similar test samples) and/or reproducible (under similar but slightly different experimental conditions). In this article, reliability and repeatability/reproducibility of a measurement system estimated within a mixed-effects nested design are monitored by relevant variability acceptance limits. A method based on the concept of empirical power (reproducibility) is used to determine these acceptance limits and thus ensure that there is a high probability of repeatability/reproducibility of the tests results. Formulas or procedures for sample size requirements for comparing the variabilities between products are derived. An example is presented to illustrate the use of the proposed method.
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