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Measurement
Elsevier BV
Measurement

Elsevier BV

0263-2241

Measurement/Journal MeasurementISTPSCIAHCI
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    Detection of amino acid with metamaterial perfect absorbers in the terahertz band

    Zhu J.Wu C.
    9页
    查看更多>>摘要：? 2022 Elsevier LtdAt present, most amino acid detection techniques have the shortcomings of laborious equipment operation procedures, long detection periods, and low accuracy, which cannot meet the requirements of high-standard amino acid identification in the food industry. Based on the related literature, some amino acids are readily soluble in water. Therefore, a novel detection and identification method can be designed based on the different refractive indices of aqueous amino acid solutions. We introduce a terahertz metamaterial perfect absorber which component successively are a Si buffer layer, a solid metallic Au reflecting layer, a SiO2 depletion layer, a main structure array layer, and a cover layer from bottom to top. The main structure array layer composed of graphene four-opening square ring structure and a golden hemisphere. The absorber achieves perfect absorption based on the principle of impedance matching. It is innovatively applied for the detection of aqueous amino acid additives solution. The absorber has two modes with absorptivity of 99.86% and 99.99% at 5.9 THz and 8.1 THz, respectively. The sensing sensitivity of both modes can reaches 1.1 THz/RIU and 1.5 THz/RIU, respectively, which has obvious advantages in other reported sensors. Experimental results show that the proposed sensor can accurately identify the four amino acids selected by 100% in this study. The research presented this paper provides an essential reference for further development of metamaterial sensors.
      原文链接:
    • NSTL
    • Elsevier

    A new approach to derive buildings footprint from light detection and ranging data using rule-based learning techniques and decision tree

    Jifroudi H.M.Mansor S.B.Ahmad N.Abdullah A.F.B....
    13页
    查看更多>>摘要：? 2022Buildings are among the most important elements in the urban structure that can affect urban planning. Therefore, it is important to create the footprint of the buildings, especially in developing cities, which is highly time-consuming and costly. Although LiDAR technology has already been used for this purpose, the need to process voluminous amounts of noisy data and make building footprint extraction in accurate. In this study, we propose a step-by-step analysis of LiDAR data using a rule-based algorithm called DB-creator in order to automatically create building footprints. DB-creator was specifically chose as it does not require external data or region information to construct the footprints. The constructed footprints based from the algorithm was compared with manually created ground truth building footprints to assess accuracy. From experimental results, RMSE for urban and rural areas were ± 0.62 m and ± 0.28 m, respectively, which is highly accurate considering LiDAR's a 0.5 m surveying distance between two points and 0.6 m distance between rows. Moreover, the kappa coefficient were 0.948 and 0.958 for the urban and rural areas, respectively (which are confirmed by T values of 150.204 and 255.553 at p ≤ 0.01 for the urban and rural areas, respectively). The Standard Errors respectively obtained for urban and rural areas were 0.001 and 0.002, reflecting slight internal variations between the built footprint maps. This also highlights the certainty of the kappa coefficient, indicating that extraction of building footprints is highly accurate.
      原文链接:
    • NSTL
    • Elsevier

    Research on intelligent measurement and driving mechanism of influencing factors of building energy saving

    Zhao L.Zhang W.
    11页
    查看更多>>摘要：? 2022 Elsevier LtdFrom project conception, planning and design, construction to operation and maintenance, construction project covers multiple aspects (including policy, resources, materials, environment, economy, and the public) and have the characteristics of complexity, long-term, and multi-factor. Based on literature research, the relationship between the main bodies of energy conservation in construction projects is established, research hypotheses are proposed, and a theoretical model of energy conservation-driven construction projects throughout the life cycle is designed in this paper. Besides, variable measurement is developed through surveys and expert interviews, and data are obtained from questionnaire surveys. Statistical analysis software such as SPSS 19 is employed to perform descriptive statistics, reliability tests, and validity analysis on sample data. Afterward, sample data is extracted through exploratory factor analysis to obtain five factors of government policy, energy-saving technology, energy-saving awareness, facility management, and energy-saving motivation. The initial structural equation model is built using AMOS 21. Additionally, the external quality and internal fit of the initial model are evaluated, and the optimized structural equation model is obtained. Finally, the theoretical model and optimization model are adopted to test the research hypothesis, clarify the relationship and path between various influencing factors, and explore the energy-saving driving mechanism of the whole life cycle of the construction project.
      原文链接:
    • NSTL
    • Elsevier

    Cooperative navigation for UAVs in GNSS-denied area based on optimized belief propagation

    Li J.Yang G.Cai Q.Niu H....
    10页
    查看更多>>摘要：? 2022 Elsevier LtdA multitude of individual unmanned aerial vehicle (UAV) cooperatively self-organized as a swarm attracts increasing attention for exploration and parallel tasks. Accurate position is essential for UAVs to avoid collision and implement control. Although the Global Navigation Satellite System (GNSS) has been integrated in UAV, it is susceptible to disruption. In this paper, we propose a novel cooperative navigation framework based on optimized belief propagation (BP) in the GNSS-denied area. Specifically, we derive a directional uncertainty model to characterize the position information of UAVs with different dynamic motions. With this model, we improve the navigation performance by designing a weighted uncertainty belief propagation (WUBP) based on information evaluation. Simulation and experimental results validate that in the dynamic scenarios, the proposed WUBP can make the swarm reap the benefits of more accurate positional estimate from UAVs with less maneuvers, higher-grade of INS or shorter time interval of GNSS signal lost.
      原文链接:
    • NSTL
    • Elsevier

    Pneumatic system for pressure probe measurements in transient flows of non-ideal vapors subject to line condensation

    Conti C.C.Guardone A.Fusetti A.Spinelli A....
    13页
    查看更多>>摘要：? 2022 Elsevier LtdThis paper presents the design, construction and commissioning of a pneumatic system for pressure probe measurements in flows of organic vapors in non-ideal conditions, namely in the thermodynamic region close to the liquid–vapor saturation curve and the critical point where the ideal gas law is not applicable. Experiments were carried out with fluid siloxane MM (hexamethyldisiloxane, C6H18OSi2), commonly employed in medium/high temperature Organic Rankine Cycles (ORCs), in the Test Rig for Organic VApors (TROVA), a blow-down wind tunnel at the Laboratory of Compressible fluid dynamics for Renewable Energy Applications (CREA lab) of Politecnico di Milano. TROVA operation is intrinsically transient due to its batch nature, with a low frequency content (～1Hz) related to the emptying of the high-pressure reservoir feeding the test section. The challenges linked to possible condensation in pneumatic lines, such as vapor–liquid menisci, hydrostatic head and mass-sink effects, were evaluated by means of theoretical calculation and experiments. To avoid these issues, a nitrogen-flushed pneumatic system for absolute and differential pressure measurements was designed and successfully tested with superheated MM vapor expanding in planar choked converging nozzles characterized by a portion with constant cross-sectional area yielding design Mach numbers of 0.2, 0.5 and 0.7. Commissioning of the complete system including a probe was performed with the first ever testing of an L-shaped Pitot tube in non-ideal subsonic flows of siloxane MM vapor at Mach numbers M=0.2 and 0.5. Measurement delay issues were identified and assessed through a dynamic testing procedure, and were solved by reducing the overall pneumatic lines volume including the one hidden within pressure transducers. The correct performance of the complete system was therefore verified for probe measurements of total, static and dynamic pressure in non-ideal flows of organic vapors. This sets the foundation for future directional pressure probes calibration and use in the characterization of such flows, as in direct measurement of total pressure losses across shocks and in testing of ORC turbine blade cascades.
      原文链接:
    • NSTL
    • Elsevier

    A multispectral thermometry based on multi-objective constraint optimization

    Zhang Y.Zou Z.Yan F.
    11页
    查看更多>>摘要：? 2022 Elsevier LtdMultispectral thermometry is a widely used non-contact temperature measurement method. How to obtain accurate target temperature under the unknown spectral emissivity is a difficult problem to be solved in this field. The emissivity assumption model method commonly used cannot be widely applied to the temperature measurement of various materials. Therefore, a multispectral thermometry based on multi-objective constraint optimization is proposed, which can accurately solve the true temperature and spectral emissivity without any prior knowledge of emissivity. In this method, the multi-objective function is established according to the radiation equations. The new emissivity constraint conditions are set for the objective function, and a mixed penalty function method is used to solve the constraint optimization problem. The simulation experiment results show that the relative error of temperature measurement for the method is less than 1%, and the average running time is less than 0.1 s, which prove the feasibility and reliability of the proposed method.
      原文链接:
    • NSTL
    • Elsevier

    5G multi-tier radio access network planning based on voronoi diagram

    Su J.Kochan O.Beshley M.Yaremko O....
    17页
    查看更多>>摘要：? 2022 The AuthorsNetwork planning of multi-layer heterogeneous mobile networks with complex topology is an important task. In this paper the spectral and energy efficiency of integrated LTE/Wi-Fi technologies for 5G are improved. A method of adaptive formation of the structure of radio access level (RAL) with the provision of the required quality of service (QoS) and the possibility of broadband data transmission is proposed. The Voronoi tessellation is used for designing the RAL of 5G mobile networks for the placement of base stations, which allowed optimum delimiting the coverage area for each base station and provide users the cell interface services. To minimize interference there was proposed a method of dynamic frequency reuse for different sizes of Voronoi cells. Modelling shows the developed method is effective both at low and at high network load, however, at high load there is a slightly smaller gain in energy efficiency than at low load.
      原文链接:
    • NSTL
    • Elsevier

    A fast automatic detection and classification of voltage magnitude anomalies in distribution network systems using PMU data

    Fuentes-Velazquez J.Angeles-Camacho C.Beltran E.Barocio E....
    15页
    查看更多>>摘要：? 2022 Elsevier LtdTimely anomaly detection and classification in voltage signals for distribution systems allows the design of preventive and corrective actions to avoid damage or loss of equipment. In this paper, an approach that combines a robust recurrence quantification analysis (RRQA) for features’ extraction that allows anomaly detection and classification through a multiclass support vector machine (SVM) algorithm is proposed. This approach is robust to noise, is free a filtering stage, has a low computational burden and is easy to interpret, becoming viable for online monitoring of distribution systems. For its validation, case studies with the presence of voltage magnitude anomalies (VMA) events that occur during normal operation conditions are analyzed. Thus, synthetic records generated through a Monte Carlo model are compared with other algorithms based on similar strategies. Finally, the proposed approach is assessed using PMU records installed in a distribution system to show its performance in a real world environment.
      原文链接:
    • NSTL
    • Elsevier

    Design and analysis of monolithic integrated MEMS vector hydrophone micro-array

    Shang Z.Zhang X.Zhang G.Zhang W....
    10页
    查看更多>>摘要：? 2022Based on the high sensitivity and miniaturization advantages of MEMS vector hydrophone, we proposed and designed a monolithic integrated micro-array vector hydrophone composed of multiple sensor units. The theoretical model shows that the micro-array can improve the structural sensitivity and output signal-to-noise ratio while eliminating the problem of port and starboard ambiguity. Meanwhile, the micro-array structure clearly reduces the installation error of conventional vector array and improve the directional accuracy. Taking 5-element micro-array as an example, the resonance frequency in wet mode reaches 956 Hz that meets the requirement of test frequency band. Through theoretical and computational analysis, the sensitivity of micro-array is increased 14 dB and the SNR is increased 3.1 dB compared with that of the single vector hydrophone. The standing-wave tube experiment verified the directional effect of vector micro-array. The research of vector hydrophone micro-array is helpful to the application of underwater acoustic engineering.
      原文链接:
    • NSTL
    • Elsevier

    In-process detection of hot-embossed two-level microstructures by the green light sensing

    Xie J.Wang R.Li L.
    8页
    查看更多>>摘要：? 2022 Elsevier LtdThe microlens distributed on microprism surface is applied in high value-added optical products. During hot-embossing, it, however, is difficult to detect the microprism and microlens heights on macro surface. Hence, an optical sensing is proposed according to energy consumption as light passing through the hot-embossed two-level microstructures. The objective is to in-process recognize the two-level micro-formed sizes. In order to depict the nonlinearity between optical-sensing and micro-forming heights, the Na?ve Bayes method (NB) and artificial neural network (ANN) were employed to distinguish the two-level heights based on the processed experiments. It is shown that the green light responds to micro-forming heights best by illumination gradients. Theoretically and experimentally, the denser microlens array is more sensitive than the microprism array. By rapidly updating the database with illumination, process variables and micro-forming heights in the small volume, the NB recognizes two-level microstructure sizes more accurately than the ANNs for efficient production.
      原文链接:
    • NSTL
    • Elsevier