Applied Mechanics and Materials Vols. 631-632

Abstract: With the development of grating displacement sensors towards higher precision and higher speed of dynamic responses, the traditional design structure is hard to solve the processing difficulty of the increasing number of poles for time grating sensors. In order to realize the analysis on the internal magnetic field distribution of high precision displacement sensor, the unequal pitch grating displacement sensor with two phase model is established using Ansoft Maxwell simulation environment. The feasibility of the two unequal pitch grating displacement sensor and magnetic field simulation are performed based on the proposed sensor model. In addition the detailed synthetic method is proposed for the simulation data. The analysis show the feasibility of the unequal pitch grating displacement sensor with two phase. The proposed displacement sensor decreases the difficulties of machining process technology and increase the pole number. As the result, the measuring precision is improved.

Abstract: Aims at the difficult to measure and influence serious in hydraulic impact fault, the intelligent diagnosis of hydraulic impact fault is proposed with improved EEMD and SVM in this paper. Three states of normal and sudden stop and suddenly reversing shock are set up on the hydraulic experimental bench. The improve EEMD is proposed by EEMD noise reduction, SVM extension signal, cubic spline interpolation improvement, and related pseudo components eliminating. The intelligent fault diagnosis in hydraulic system is researched by the improve EEMD to extract the IMF energy as feature vector, and the SVM training classification. Because distinguish and clear between normal state samples with the two impact fault samples, classification results are very right under a linear, polynomial kernel function, or a RBF, sigmoid and precomputed kernel function.

Abstract: To solve the poor location accuracy of wireless sensor networks using Received Signal Strength Indication (RSSI) ranging. Time Of Flight (TOF) ranging is used to ensure the accuracy based on two optional physical layer of Impulse Radio-Ultra Wide-Band (IR-UWB) and Chirp Spread Spectrum (CSS) in IEEE802.15.4a. In this paper, we designed ranging module utilizing CSS and UWB. In the Line Of Sight (LOS) and None Line Of Sight (NLOS) environments ranging accuracy test is implemented, the test results show that the IR-UWB ranging technology can achieve higher ranging accuracy and better multipath resistance compared to CSS.

Abstract: The diagnostic conclusions by IEC60599 gas ratio method cannot be directly applied to DS Evidence Theory for information fusion. In order to solve the problem, this research proposed a calculation method for transformer fault BPA based on spatial interpolation. Firstly, the fault characteristic space defined by IEC60599 gas ratio method was analyzed. Based on the analysis results, the entire fault characteristic space was divided into several rectangular units through spatial discretization. Next, the BPA function of faults in each unit was formulated by 8-node hexahedral unit interpolation. In this way, the continuous BPA function of faults in the entire space was obtained. This method not only met the requirements of BPA function but also enabled the numerical reflection of various fault possibilities in the calculation results. Thus, this method extended the application of IEC60599 gas ratio method. With example calculation, the correctness and feasibility of this method in actual engineering projects were verified.

Abstract: In order to help the blind and the visual impaired people to travel outdoor safely, a guide cane system is designed in this paper. It comprises the thin cane as well as the rich remote workstation. When travelling in outdoor environments, the blind could easily set a destination via the voice recognition interface. Meanwhile, the goal and current locations are transmitted to the remote center in real time by using GPS and GPRS modules. After planning a navigation path globally, the route information is downloaded to the guide cane. All guiding information can be expressed to the blind in both auditory and tactile modes. In addition, an RGB-D camera is used to capture dynamic visual environmental information which is uploaded to the remote center for further processing, while ultrasonic sensors are employed to help avoid obstacles around. Testing results show that the system is simple to operation, and has a good usability and reliability.

Abstract: Eye gaze trackers have numerous applications in medicine, gaming, advertising, teaching and learning, intelligent transportation, etc. In this paper, we proposed a novel approach for video based eye gaze trackers. In this approach, we apply the circumcircle of triangle principle to the limbus part of human eyes. First, an image pre-processing step is used to find three triangle vertices located on limbus. Then, we use the coordinates of these points to determine the limbus center using the circumcircle of triangle principle. Furthermore, when the proposed system fails to find the three useful points on limbus of one eye, a mirror procedure is adopted to find its limbus center based on the information extracted from the other eye. The proposed method can solve the occlusion problem caused by the eyelids that cover part of limbus. The experimental results show that the average eye detection rate is 98.39% and the average error between estimated and actual centers of limbus is only 1.99 pixels. The proposed method is simple, fast, and effective.

Abstract: The temperature change of the power transmission line and substation equipment can reflect their potential safety hazard caused by their aging and overload. Based on the nonlinear analysis of forecasting substation equipment temperature data can realize effectively early warning of equipment failure and avoid huge losses caused by the accident. This paper puts forward a method for temperature forecasting, based on the chaotic time series and BP neural network. It collects data from wireless temperature sensors to establish a time series of substation equipments’ temperature. Software simulation results showed that the prediction method has higher prediction accuracy than that of the traditional method.

Abstract: This paper mainly analyzes the principle and application conditions of temperature controlled tank-heat flow meter method in field testing the heat transfer coefficient. And according to the actual engineering examples, using temperature controlled tank-heat flow meter method to test the heat transfer coefficient of fly ash autoclaved aerated concrete building envelope. Analyzing and studying the testing data, design value and theoretical calculating value.

Abstract: Vegetation health index detector obtained by remote sensing is analyzed. Remote sensing information of wide range vegetation is complex since there are a lot of plants with their own spectral characteristics in a certain area. After absorbing the light, some light sensitive characteristics will have some change, which lead to the change of the entire vegetation health spectral curve. In traditional method, vegetation health is shown by the spectral remote sensing characteristic curve of green plant. There will be some misjudgment if the spectral remote sensing characteristic curve is distorted. Reflectance spectral characteristics analysis algorithm with classification constraint for the plant health is discussed in this paper. Traditional detection method is optimized according to the data classification theory. With the support of the optimization, wide range vegetation spectral characteristics can be distinguished and the interference of wide range of strong light is avoided. The new method can decrease the vegetation health detection fallacious rate, and it is showed in the simulation result.

Abstract: Biggish animal models were applied in perfusion system for ex vivo research. But the disadvantages is the needs for more research funding and better surgical skills to perform which many researchers lack. A minor-caliber vessel perfusion system for ex vivo was designed and constructed to simulate pulsatile situation in vivo. The parameters mimicked the physiological measures of New Zealand rabbit. Pulse is 250 beats per minute. Diastolic blood pressure is 12.666KPa, and systolic blood pressure is 14.665KPa. The vessel perfusion system can regulate pulse pressure, the state of laminar flow, and shear stress. To culture several vessels simultaneously for control, the pressures data of 4 baths was analyzed with one way analysis of variance. The results show that the perfusion system is stable, and pressure difference of 4 baths is not significant.