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Abstract Background Conventional prenatal screening tests, such as maternal serum tests and ultrasound scan, have limited resolution and accuracy. Methods We developed an advanced noninvasive prenatal diagnosis method based on massively parallel sequencing. The Noninvasive Fetal Trisomy (NIFTY) test, combines an optimized Student’s t-test with a locally weighted polynomial regression and binary hypotheses. We applied the NIFTY test to 903 pregnancies and compared the diagnostic results with those of full karyotyping. Results 16 of 16 trisomy 21, 12 of 12 trisomy 18, two of two trisomy 13, three of four 45, X, one of one XYY and two of two XXY abnormalities were correctly identified. But one false positive case of trisomy 18 and one false negative case of 45, X were observed. The test performed with 100% sensitivity and 99.9% specificity for autosomal aneuploidies and 85.7% sensitivity and 99.9% specificity for sex chromosomal aneuploidies. Compared with three previously reported z-score approaches with/without GC-bias removal and with internal control, the NIFTY test was more accurate and robust for the detection of both autosomal and sex chromosomal aneuploidies in fetuses. Conclusion Our study demonstrates a powerful and reliable methodology for noninvasive prenatal diagnosis.

Sublevel caving method without bottom column and filling method were used for mining in a mine. This paper studied the change of stope ground pressure and stope stability when two mining methods were used simultaneously. FLAC3D numerical simulation technology was used to simulate the evolution law of stope ground pressure in this mine, and microseismic monitoring technology was used to verify the simulation results. The results showed that with the development of sublevel caving method, the stability of the lower consolidated backfill was significantly improved, and the force on the lower stope pillar was on the decline. After the mining of sublevel caving method, the vertical stress of the lower stope pillar decreased by about 35%. Thus, it was proved that the mining method of sublevel caving without bottom column can effectively relieve the ground pressure in the lower filling stope and is conducive to improving the stability of stope. [ABSTRACT FROM AUTHOR]

The bedding rock slope is affected by natural geological structure and its stability is relatively poor. However, under the influence of strong degradation factors such as heavy rain, blasting and earthquakes, its stability is more threatened. Therefore, based on the strength reduction theory, this paper analyzed the stability of the bedding rock slope of a mine by numerical simulation. Meanwhile, this paper studied the position of the sliding surface of the rock slope, the lateral deformation and the stress change law of the rock slope under the bedding design and two optimization schemes under the three conditions of heavy rain, blasting and earthquake. The research results indicated that: the earthquake had the greatest impact on the stability of the bedding slope of the mine; in addition, the safety factor of the slope under the conditions of the proposed design scheme was lower than the standard value, and the slope was in an unstable state. Through the optimization study of the bedding slope of the mine, the optimal design plan of the mine was obtained. [ABSTRACT FROM AUTHOR]

The pressure in the wheel cylinder plays an important role in the anti-lock braking system, but direct measurement usually needs expensive sensors. Therefore, estimation of the pressure in the wheel cylinder is of great significance to optimize the algorithm of the anti-lock braking system. There are two commonly used estimation methods: one is based on the hydraulic model, and the other is based on the equation for the tyre dynamics. Both of these, however, suffer from inadequacies. The former method is sensitive to the accuracy of the model in practical applications, and an accumulated error appears if some parameters of the process are not sufficiently accurate. In the latter method the pressure in the wheel cylinder is calculated for each cycle but, when the vehicle is running, the fluctuations in the deceleration are relatively large. To estimate the pressure more accurately, a novel method is proposed in this paper, which combines these two methods on the basis of the extended Kalman filter. The method can compensate for the inadequacies of the two methods mentioned above by using the variation in the wheel speed as the observation variable to modify the hydraulic model. It can decrease its sensitivity to the accuracy of the hydraulic model and improve the accuracy of the estimated magnitude of the pressure. The estimated results are compared with the real values which are obtained by using a pressure sensor on a typical low-friction road and on an asphalt road; in addition, the effectiveness of the novel method is validated by hardware-in-the-loop tests and vehicle tests. The results show that the proposed method can provide an accurate estimation of the pressure in the wheel cylinder during hydraulic control of the anti-lock braking system or any other brake control system. [ABSTRACT FROM AUTHOR]

As is known, estimation of the dynamic states of a vehicle plays an important role in safety control, but it is difficult to obtain the vehicle states accurately without expensive measurement instruments because of the non-linear and huge hysteretic characteristics. Nowadays, many methods have been adopted to solve this problem, the results of which are not ideal because it is assumed that the key parameters are constant, in particular in severe manoeuvres. This paper develops a novel estimation method for the vehicle states using the extended Kalman filter with a fusion algorithm. First, the optimal key parameters (the equivalent roll stiffness and the equivalent roll damping) are identified by genetic algorithms using the data from the relationship between the key parameters and the vehicle real-time states. Then, a novel non-linear observer for the side-slip angle and the roll angle is established on the basis of a four-degree-of-freedom vehicle model by utilizing the identified key parameters and the sensors mounted on normal vehicles. The performance of the observer is investigated using both simulations and real-vehicle experiments. The results demonstrate the reasonable accuracy of the estimation method proposed in this paper. [ABSTRACT FROM AUTHOR]