scholarly journals An Information Entropy-Based Modeling Method for the Measurement System

Entropy ◽  
2019 ◽  
Vol 21 (7) ◽  
pp. 691 ◽  
Author(s):  
Li Kong ◽  
Hao Pan ◽  
Xuewei Li ◽  
Shuangbao Ma ◽  
Qi Xu ◽  
...  

Measurement is a key method to obtain information from the real world and is widely used in human life. A unified model of measurement systems is critical to the design and optimization of measurement systems. However, the existing models of measurement systems are too abstract. To a certain extent, this makes it difficult to have a clear overall understanding of measurement systems and how to implement information acquisition. Meanwhile, this also leads to limitations in the application of these models. Information entropy is a measure of information or uncertainty of a random variable and has strong representation ability. In this paper, an information entropy-based modeling method for measurement system is proposed. First, a modeling idea based on the viewpoint of information and uncertainty is described. Second, an entropy balance equation based on the chain rule for entropy is proposed for system modeling. Then, the entropy balance equation is used to establish the information entropy-based model of the measurement system. Finally, three cases of typical measurement units or processes are analyzed using the proposed method. Compared with the existing modeling approaches, the proposed method considers the modeling problem from the perspective of information and uncertainty. It focuses on the information loss of the measurand in the transmission process and the characterization of the specific role of the measurement unit. The proposed model can intuitively describe the processing and changes of information in the measurement system. It does not conflict with the existing models of the measurement system, but can complement the existing models of measurement systems, thus further enriching the existing measurement theory.

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 588
Author(s):  
Benjamin C. Smith ◽  
Brett C. Ramirez ◽  
Steven J. Hoff

Many climate-controlled agricultural buildings use direct gas-fired circulating heaters (DGFCH) for supplement heat. There is no standardized test to calculate thermal efficiency for these heaters. This study aimed to develop a measurement system and analytical analysis for thermal efficiency, quantify the measurement uncertainty, and assess economics of DGFCH efficiency. The measurement system developed was similar to the ASHRAE 103 standard test stand with adaptations to connect the apparatus to the DGFCH. Two different propane measurement systems were used: input ratings < 30 kW used a mass flow system and input ratings > 30 kW used a volumetric gas meter. Three DGFCHs (21.9, 29.3, 73.3 kW) were tested to evaluate the system. Thermal efficiencies ranged from 92.4% to 100.9%. The resulting uncertainty (coverage factor of 2; ~95% Confidence Interval) ranged from 13.1% to 30.7% for input ratings of 56.3 to 11.4 kW. Key sources of uncertainty were propane and mass flow of air measurement. The economic impact of 1% difference in thermal efficiency ranged from USD $61.3 to $72.0 per heating season. Refinement of the testing system and procedures are needed to reduce the uncertainty. The application of this system will aid building designers in selection of DGFCHs for various applications.


Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 2896
Author(s):  
Pratham Singh ◽  
Michael Esposito ◽  
Zach Barrons ◽  
Christian A. Clermont ◽  
John Wannop ◽  
...  

One possible modality to profile gait speed and stride length includes using wearable technologies. Wearable technology using global positioning system (GPS) receivers may not be a feasible means to measure gait speed. An alternative may include a local positioning system (LPS). Considering that LPS wearables are not good at determining gait events such as heel strikes, applying sensor fusion with an inertial measurement unit (IMU) may be beneficial. Speed and stride length determined from an ultrawide bandwidth LPS equipped with an IMU were compared to video motion capture (i.e., the “gold standard”) as the criterion standard. Ninety participants performed trials at three self-selected walk, run and sprint speeds. After processing location, speed and acceleration data from the measurement systems, speed between the last five meters and stride length in the last stride of the trial were analyzed. Small biases and strong positive intraclass correlations (0.9–1.0) between the LPS and “the gold standard” were found. The significance of the study is that the LPS can be a valid method to determine speed and stride length. Variability of speed and stride length can be reduced when exploring data processing methods that can better extract speed and stride length measurements.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Lei Xu ◽  
Ning Zhang ◽  
Liqing Fang ◽  
Huadong Chen ◽  
Pengfei Lin ◽  
...  

The magnetic gradient full-tensor measurement system is diverse, and the magnetometer array structure is complex. Aimed at the problem, seven magnetic gradient full-tensor measurement system models are studied in detail. The full-tensor measurement theories of the tensor measurement arrays are analyzed. Under the same baseline distance, the magnetic dipole model is used to simulate the measurement system. Based on different measurement systems, the paper quantitatively compares and analyzes the error of the structure. A more optimized magnetic gradient full-tensor measurement system is suggested. The simulation results show that the measurement accuracy of the planar measurement system is slightly higher than that of the stereo measurement system. Among them, the cross-shaped and square measurement systems have relatively smaller structural errors and higher measurement accuracy.


2021 ◽  
Vol 2090 (1) ◽  
pp. 012138
Author(s):  
I M Indrupskiy ◽  
P A Chageeva

Abstract Mathematical models of phase behavior are widely used to describe multiphase oil and gas-condensate systems during hydrocarbon recovery from natural petroleum reservoirs. Previously a non-equilibrium phase behavior model was proposed as an extension over generally adopted equilibrium models. It is based on relaxation of component chemical potentials difference between phases and provides accurate calculations in some typical situations when non-instantaneous changing of phase fractions and compositions in response to variations of pressure or total composition is to be considered. In this paper we present a thermodynamic analysis of the relaxation model. General equations of non-equilibrium thermodynamics for multiphase flows in porous media are considered, and reduced entropy balance equation for the relaxation process is obtained. Isotropic relaxation process is simulated for a real multicomponent hydrocarbon system with different values of characteristic relaxation time using the non-equilibrium model implemented in the PVT Designer module of the RFD tNavigator simulation software. The results are processed with a special algorithm implemented in Matlab to calculate graphs of the total entropy time derivative and its constituents in the entropy balance equation. It is shown that the constituents have different signs, and the greatest influence on the entropy is associated with the interphase flow of the major component of the mixture and the change of the total system volume in the isotropic process. The characteristic relaxation time affects the rate at which the entropy is approaching its maximum value.


Author(s):  
Алексей Николаевич Самойлов ◽  
Юрий Михайлович Бородянский ◽  
Александр Валерьевич Волошин

В процессе автоматизации решения прикладных измерительных задач, в том числе на базе фотограмметрических методов, возникает проблема соответствия измерительной системы объекту и условиям измерения. Для того чтобы измерительная система позволяла заранее оценить возможность получения достоверных результатов, а также наилучшим образом подстраивалась под условия измерения, необходимо наличие специализированных алгоритмов и моделей. В общем случае такие модели ориентированы на квалифицированных технических специалистов, обладающих необходимыми знаниями в области информационных технологий. Особенностью применения фотограмметрических измерительных систем в лесной и металлургической промышленности является низкая квалификация пользователей в сфере информационных технологий, что обуславливается характером выполняемых работ и условиями привлечения. Данный фактор не позволяет решить задачу подстройки системы традиционными методами, в которых процессом настройки управляет пользователь. В этой связи в статье предлагается модель и алгоритм формирования измерительной системы по первичным входным данным, в котором процессом настройки управляет сама система. In the process of automating the solution of applied measurement tasks, including on the basis of photogrammetric methods, there is a problem of compliance of the measurement system with the object and measurement conditions. In order for the measuring system to assess in advance the possibility of obtaining reliable results, as well as to best adapt to the conditions of measurement, it is necessary to have specialized algorithms and models. In general, such models are aimed at qualified technicians with the necessary knowledge in the field of information technology. A feature of the application of photogrammetric measurement systems in the forestry and metallurgical industry is the low qualification of users in the field of information technology, which is determined by the nature of the work performed and the conditions of attraction. This factor does not solve the problem of adjusting the system by traditional methods in which the user controls the configuration process. In this regard, the article proposes a model and algorithm for forming a measuring system from primary input data, in which the system itself controls the adjustment process.


2014 ◽  
Vol 952 ◽  
pp. 307-310
Author(s):  
Yan Ming Wei ◽  
Hua Ping Li ◽  
Hai Long Gao

In order to improve the modeling ability for nonlinear system, an Elman modeling method based on Particle Swarm Optimization (PSO) algorithm is proposed. It uses PSO algorithm to optimize the parameters of Elman network. The simulation result shows that the proposed hybrid method combined Elman with PSO algorithm has a good modeling performance with fast training rate for complex nonlinear system.


Author(s):  
Liu Yue ◽  
Zhao Chun ◽  
Zhang Lin

In the process of complex product design, modeling in different fields and different disciplines is often involved. Designers often face many different development kits, platforms, and theories, among which significant differences exist. Especially in the process of algorithm-hardware implementation, it is necessary to have mastery of the knowledge including algorithm, hardware, circuit, and system engineering. In this paper, a modeling method of algorithm-hardware based on SysML is proposed to reduce the difficulty of algorithm-hardware modeling. By using the method, the designers who do not know the knowledge of hardware can also easily build the algorithm-hardware model. In this method, a method of graphical system modeling based on SysML is used, where the elements of the algorithm-hardware model are described by SysML graphical models. Then, the SysML graphical models are converted to Very-High-Speed Integrated Circuit Hardware Description Language. At last, a detecting algorithm of random number is complemented by the modeling method in this paper and the simulation results are presented at the conclusion.


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