Marine in situ testing is a necessary step for stereotyping newly developed marine sensors. The use of test sites in the Yangtze Estuary area, which has high turbidity and abundant nutrients, can effectively reduce th...Marine in situ testing is a necessary step for stereotyping newly developed marine sensors. The use of test sites in the Yangtze Estuary area, which has high turbidity and abundant nutrients, can effectively reduce the needed testing time owing to its harsh conditions. Five test stations were established, and a floating buoy and fixed test equipment were designed. A control system, including a sensor connection, data processor, video remote transmission, and corresponding control algorithm, was developed. The control system enabled the nondestructive monitoring of biological attachments and bidirectional, real-time communication between an upper server on land and the control system at the test sites. The dissolved oxygen(DO), temperature, and pH data of DOS600 and DPS600 sensors were compared with those of AP2000 sensors. Temperature recording using the DOS600 sensor was performed nearly as well as that of the AP2000 sensor. The mean DO values(standard deviations) were 8.414 mg L-1(2.068) and 6.896 mg L-1(1.235) for the DOS600 and AP2000 sensors, respectively, indicating that the DOS600 performance was unsatisfactory. The pH recording of the DPS600 was slightly worse than that of the AP2000 sensor. Experimental results showed that the DO value was more easily affected by the buoy movement of waves compared to the pH and temperature. Moreover, data fluctuations showed that the DO and pH parameters were more vulnerable to biofouling than temperature. Waves and biofouling create a harsh test environment, and the performance difference between the developed sensors and a standard sensor can be obtained in a short time period.展开更多
The need for efficient and reproducible development processes for sensor and perception systems is growing with their increased use in modern vehicles. Such processes can be achieved by using virtual test environments...The need for efficient and reproducible development processes for sensor and perception systems is growing with their increased use in modern vehicles. Such processes can be achieved by using virtual test environments and virtual sensor models. In the context of this, the present paper documents the development of a sensor model for depth estimation of virtual three-dimensional scenarios. For this purpose, the geometric and algorithmic principles of stereoscopic camera systems are recreated in a virtual form. The model is implemented as a subroutine in the Epic Games Unreal Engine, which is one of the most common Game Engines. Its architecture consists of several independent procedures that enable a local depth estimation, but also a reconstruction of a whole three-dimensional scenery. In addition, a separate programme for calibrating the model is presented. In addition to the basic principles, the architecture and the implementation, this work also documents the evaluation of the model created. It is shown that the model meets specifically defined requirements for real-time capability and the accuracy of the evaluation. Thus, it is suitable for the virtual testing of common algorithms and highly automated driving functions.展开更多
For our research,a new hybrid experimental-computational method is presented.We applied a least squares fitting method(LSFM) to reconstruct the wood moisture content(WMC) from the data measured with a planar capacitan...For our research,a new hybrid experimental-computational method is presented.We applied a least squares fitting method(LSFM) to reconstruct the wood moisture content(WMC) from the data measured with a planar capacitance sensor.A boundary element method(BEM) was used to compute the relationship between capacitance and the dielectric constant.A functional relationship between MC and the dielectric constant was identified by LSFM.The agreement of this final computation result with the experimental data indicates that this method can be used to estimate the WMC quickly and effectively with engineering analysis.Compared with popular statistical methods,a large number of experiments are avoided,some costs of testing are reduced and the efficiency of testing is enhanced.展开更多
In this paper, an optical fiber sensor is designed by using optical Faraday effect. It is composed of fiber collimator, polarizer, magneto-optical crystal and mirror. Based on the magnetic flux leakage (MFL) theory, T...In this paper, an optical fiber sensor is designed by using optical Faraday effect. It is composed of fiber collimator, polarizer, magneto-optical crystal and mirror. Based on the magnetic flux leakage (MFL) theory, The optical fiber sensor was placed between two permanent magnets with the N-pole. Therefore, the optical fiber sensing system was built to detect the defective ferromagnetic objects. Theoretical and experimental studies shown that the system can identify a little defects, such as irons’ blind hole (diameter φ =?3mm , depth t = 4mm?), irons’ grooves (length l= 30mm , width?ω = 10mm ), hole (φ?=?3mm ) and crackle etc. The system has the characteristics of small size, high sensitivity, fast signal response and high resolution. In terms of the defective oil and gas pipelines detection, The optical fiber sensing system is used in non-destructive testing, which will be valuable and meaningful.展开更多
基金supported by the National Key Research and Development Plan(No.2019YFD0901300)the Shanghai Science and Technology Innovation Action Plan(No.16DZ1205100)the Shanghai Agriculture Applied Technology Development Program(No.T20180303)。
文摘Marine in situ testing is a necessary step for stereotyping newly developed marine sensors. The use of test sites in the Yangtze Estuary area, which has high turbidity and abundant nutrients, can effectively reduce the needed testing time owing to its harsh conditions. Five test stations were established, and a floating buoy and fixed test equipment were designed. A control system, including a sensor connection, data processor, video remote transmission, and corresponding control algorithm, was developed. The control system enabled the nondestructive monitoring of biological attachments and bidirectional, real-time communication between an upper server on land and the control system at the test sites. The dissolved oxygen(DO), temperature, and pH data of DOS600 and DPS600 sensors were compared with those of AP2000 sensors. Temperature recording using the DOS600 sensor was performed nearly as well as that of the AP2000 sensor. The mean DO values(standard deviations) were 8.414 mg L-1(2.068) and 6.896 mg L-1(1.235) for the DOS600 and AP2000 sensors, respectively, indicating that the DOS600 performance was unsatisfactory. The pH recording of the DPS600 was slightly worse than that of the AP2000 sensor. Experimental results showed that the DO value was more easily affected by the buoy movement of waves compared to the pH and temperature. Moreover, data fluctuations showed that the DO and pH parameters were more vulnerable to biofouling than temperature. Waves and biofouling create a harsh test environment, and the performance difference between the developed sensors and a standard sensor can be obtained in a short time period.
文摘The need for efficient and reproducible development processes for sensor and perception systems is growing with their increased use in modern vehicles. Such processes can be achieved by using virtual test environments and virtual sensor models. In the context of this, the present paper documents the development of a sensor model for depth estimation of virtual three-dimensional scenarios. For this purpose, the geometric and algorithmic principles of stereoscopic camera systems are recreated in a virtual form. The model is implemented as a subroutine in the Epic Games Unreal Engine, which is one of the most common Game Engines. Its architecture consists of several independent procedures that enable a local depth estimation, but also a reconstruction of a whole three-dimensional scenery. In addition, a separate programme for calibrating the model is presented. In addition to the basic principles, the architecture and the implementation, this work also documents the evaluation of the model created. It is shown that the model meets specifically defined requirements for real-time capability and the accuracy of the evaluation. Thus, it is suitable for the virtual testing of common algorithms and highly automated driving functions.
基金supported by the Central University Basic Research Professional Expenses Special Foundation of Harbin Engineering University (Grant No. HEUCFL10101109)
文摘For our research,a new hybrid experimental-computational method is presented.We applied a least squares fitting method(LSFM) to reconstruct the wood moisture content(WMC) from the data measured with a planar capacitance sensor.A boundary element method(BEM) was used to compute the relationship between capacitance and the dielectric constant.A functional relationship between MC and the dielectric constant was identified by LSFM.The agreement of this final computation result with the experimental data indicates that this method can be used to estimate the WMC quickly and effectively with engineering analysis.Compared with popular statistical methods,a large number of experiments are avoided,some costs of testing are reduced and the efficiency of testing is enhanced.
文摘In this paper, an optical fiber sensor is designed by using optical Faraday effect. It is composed of fiber collimator, polarizer, magneto-optical crystal and mirror. Based on the magnetic flux leakage (MFL) theory, The optical fiber sensor was placed between two permanent magnets with the N-pole. Therefore, the optical fiber sensing system was built to detect the defective ferromagnetic objects. Theoretical and experimental studies shown that the system can identify a little defects, such as irons’ blind hole (diameter φ =?3mm , depth t = 4mm?), irons’ grooves (length l= 30mm , width?ω = 10mm ), hole (φ?=?3mm ) and crackle etc. The system has the characteristics of small size, high sensitivity, fast signal response and high resolution. In terms of the defective oil and gas pipelines detection, The optical fiber sensing system is used in non-destructive testing, which will be valuable and meaningful.
