Dynamic Simulation Analysis of Track Tension and the Influencing Factors of Deep-Sea Tracked Mining Vehicle

The deep-sea mining miner requires good passability to operate in complex and changeable terrain environment of the seabed. Among them, the track tension is an important factor to ensure the normal running of the vehicle. Aiming at the complex track tension problem on track link, the forces on each component of the tracked system were analyzed, and the theoretical formulas of track tension were established. The theoretical estimation and dynamic simulation of track tension in uniform speed were carried out by using the multibody dynamics model of the tracked vehicle, and the rationality of the theoretical estimation formula was verified. The influencing factors of track tension also were analyzed, and the significance of each factor on track was discussed by dynamic simulation. The results provided a theoretical basis for design of tracked vehicles.

Characteristics of Physicochemical Properties of Chalky Grains of Japonica Rice Generated by High Temperature during Ripening

Global warming has caused devastating damage to starch biosynthesis, which has led to the increase in chalky grains of rice. This study was conducted to characterize the qualities of chalky rice grains and to develop the estimation formulae for their quality damage degree. We evaluated the chalkiness of 40 Japonica rice samples harvested in 2019, in Japan. Seven samples with a high ratio of chalky rice grains were selected and divided into two groups (whole grain and chalky grain). As a results of the various physicochemical measurements, it was shown that the surface layer hardness (H1) of cooked rice grains from chalky grains was significantly lower, and their overall hardness was significantly lower than those from the whole grains. In addition, α- and β-amylase activities, and sugar contents of the chalky rice grains were significantly higher than those of the whole rice grains. The developed estimation formula for the degree of retrogradation of H1 based on the α-amylase activities and pasting properties, showed correlation coefficients of 0.84 and 0.81 in the calibration and validation tests, respectively. This result presents the formula that could be used to estimate and to characterize the cooking properties of the rice samples ripened under high temperature.

Q estimation based on the logarithmic spectral area double difference

The Q factor is an essential parameter describing the characteristics of medium absorption within a material during wave propagation. When a seismic wave propagates within the attenuating media, its amplitude decreases and frequency band narrows, resulting in a variation in its logarithmic spectral area. Based on these effects, we calculate the logarithmic spectral area difference (LSAD) before and after attenuation and set a division point to divide the LSAD into two parts. We then compute the difference between the two LSADs to derive a new Q-estimation formula based on computation of the logarithmic spectral area double difference (LSADD). To improve the noise robustness of the Q estimation, we select multiple different division points to calculate the Q factors and consider their average value as our final estimate. We then compare and analyze the noise robustness and bandwidth sensitivity of our technique with other commonly used methods. These results demonstrate that our approach is the most accurate and robust, and least sensitive to the frequency band when processing noisy synthetic seismograms. Finally, we apply our methodology to field vertical seismic profile (VSP) and seismic reflection data, further illustrating the effectiveness of this method to estimate the Q factor.

Estimation Formula of Modal Frequency of High-Rise Buildings under Different Wind Speeds during Typhoons

On 18 October 2016, the wind-induced effects of a high-rise building with square section was measured by the monitoring system in Haikou of China during Typhoon Sarika. The wind characteristics atop the building and the time-history responses of the translational and rotational accelerations on different floors were measured by the monitoring system; the first three modal parameters were identified according to the measured acceleration. The results show that the combinations of the cross spectral density function, phase spectrum, and coherence function can clearly judge the phase of the measured floors in the frequency resonance area as well as its modal frequencies at the first three orders. The modal frequencies at the first three orders decrease linearly with the growth of mean wind speed within the range of 0~20m/s. The estimation formula of the modal frequencies of high-rise buildings considering the influences of different wind speeds is put forward, which is expected to fill the gap in the existing specification for the quantitative analysis of the influences of wind-loads on the fundamental frequencies of high-rise buildings.

The Role of Athletic Self-efficacy and Athletic Perfectionism in Predicting Athletic Performance of Gazi University Student Athletes

Athletic performance is the physical and mental effort of an individual or a sports team to win and defeat the other person or team. The aim of this study was to investigate the role of athletic self-efficacy and athletic perfectionism in predicting athletic performance of athletic students of Gazi University.The method of this study is descriptive and correlational. The statistical population includes all student athletes of Gazi University, which is 360 people. To determine the sample size, Cochran’s sample size estimation formula was used and the number of samples was equivalent to 186 individuals selected by simple random sampling method. Standard questionnaires on athletic self-efficacy, athletic perfectionism and athletic performance were used to collect data. The data were analyzed using SPSS 24 software. Descriptive statistics for quantitative variables were presented as mean and standard deviation. The regression coefficient was used to determine the role of athletic self-efficacy and perfectionism in predicting students’ athletic performance.Athletic self-efficacy and athletic perfectionism play an important role in predicting athletic performance of student athletes. Athletic self-efficacy and athletic perfectionism predicted 0.54 and 0.46 (p < 0.05) of changes in athletic performance, respectively.As athletic self-efficacy and athletic perfectionism increase, so does athletic performance in student athletes. Coaches are advised to pay attention not only to physical condition but also to psychological characteristics and especially to indicators of perfectionism and self-efficacy when selecting players.

Estimation of Internal Maximum Thermal Stress of Tunnel Side Wall Lining Concrete During Construction Period

Thermal cracks in lining concrete of large section hydraulic tunnel usually occur in side walls during construction, and most of them are harmful penetrating cracks. In order to meet the needs of real-time rapid control for engineering design in construction period, nine influencing factors of maximum tensile of side wall lining concrete σmax during construction period are determined on the basis of comprehensive analysis of temperature stress effects and finite element simulations, and their influencing regularities are analyzed. Then the estimation formula of σmax and real-time control method of thermal crack are put forward. Through the application of real-time temperature control and crack prevention control of lining concrete in flood discharge tunnel, the estimation formula of σmax and the real-time thermal crack control method are proved to be correct and applicable.

A Convenient Way to Determine the Optimum Angle of Incidence of Fizeau Interferometer

In a Fizeau interferometer, off-axis illumination will lead to fringe optimization. Primarily due to the unique structure of our interferometer, we first analyze the influence of the optical properties of the parallel plate as a part of the interferometer on the optimal incident angle. Generally, the incident angle determination is mainly based on the graphing method proposed by Langenbeck and the estimation formula proposed by Kajava. However, Langenbeck’s method is cumbersome, and the error of Kajava’s estimation formula is large. Based on the predecessors, this paper proposes a modified method of determining the optimal angle of incidence and further derives more accurate optimal angle expressions than Kajava’s. By simply substituting the wedge angle of the wedge cavity and the reflectivity of the cavity, the optimum incidence angle can be obtained immediately. Thus, it eliminates the tedious and complex process of finding the optimum incident angle by graphing method and makes the formula method the simplest method to find the optimum incident angle. Finally, the comparison of the interference intensity at the optimum incidence angle calculated by the improved method and normal incidence is given. It is found that the beam has a good suppression effect on the sub-peak when it is incident at the optimum incident angle calculated by the method in this paper.

The One Standard Error Rule for Model Selection: Does It Work?

Previous research provided a lot of discussion on the selection of regularization parameters when it comes to the application of regularization methods for high-dimensional regression. The popular “One Standard Error Rule” (1se rule) used with cross validation (CV) is to select the most parsimonious model whose prediction error is not much worse than the minimum CV error. This paper examines the validity of the 1se rule from a theoretical angle and also studies its estimation accuracy and performances in applications of regression estimation and variable selection, particularly for Lasso in a regression framework. Our theoretical result shows that when a regression procedure produces the regression estimator converging relatively fast to the true regression function, the standard error estimation formula in the 1se rule is justified asymptotically. The numerical results show the following: 1. the 1se rule in general does not necessarily provide a good estimation for the intended standard deviation of the cross validation error. The estimation bias can be 50–100% upwards or downwards in various situations; 2. the results tend to support that 1se rule usually outperforms the regular CV in sparse variable selection and alleviates the over-selection tendency of Lasso; 3. in regression estimation or prediction, the 1se rule often performs worse. In addition, comparisons are made over two real data sets: Boston Housing Prices (large sample size n, small/moderate number of variables p) and Bardet–Biedl data (large p, small n). Data guided simulations are done to provide insight on the relative performances of the 1se rule and the regular CV.

Répartition jointe dans les classes de résidus de la somme des chiffres pour deux représentations d’Ostrowski

Résumé. Pour deux entiers [Formula: see text], nous posons [Formula: see text] et [Formula: see text] (où [Formula: see text]) et nous notons respectivement [Formula: see text] et [Formula: see text] les fonctions sommes des chiffres dans les [Formula: see text] et [Formula: see text]-représentations d’Ostrowski de [Formula: see text]. Soient [Formula: see text] des entiers positifs tels que [Formula: see text] et [Formula: see text], nous obtenons une estimation en [Formula: see text] avec un terme d’erreur [Formula: see text] pour le cardinal de l’ensemble suivant [Formula: see text] pour tous les entiers [Formula: see text] et [Formula: see text] Notre résultat peut être comparé à celui de Bésineau et Kim qui ont traité le cas des [Formula: see text]-représentations dans différentes bases (qui sont premières entre elles). For two distinct integers [Formula: see text], we set [Formula: see text] and [Formula: see text] (where [Formula: see text] is the continued fraction [Formula: see text]) and we let [Formula: see text] and [Formula: see text] denote respectively, the sum of digits functions in the Ostrowski [Formula: see text] and [Formula: see text]-representations of [Formula: see text]. Let [Formula: see text] be positive integers satisfying [Formula: see text] and [Formula: see text], we obtain an estimation [Formula: see text] with an error term [Formula: see text] for the cardinality of the following set [Formula: see text] for all integers [Formula: see text] and [Formula: see text] Our result should be compared to that of Bésineau and Kim who addressed the case of the [Formula: see text]-representations in different bases (that are coprime).