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At present, further reducing the mass of permanent magnet brushless dc motor has become a new demand for the development of humanoid robots. In order to achieve this goal, this paper presents a new design idea of motor. Compared with the motor currently used in robots, the new method will reduce the mass of the motor and improve the torque density as well, while ensuring the same torque output. This design method mainly uses HALBACH array for excitation. Through finite element analysis, the distribution rules of magnetic field, back electromotive force, torque and cogging torque of the motor are obtained. Experimental result shows that the actual torque of the motor reaches the goal of our design, and the rotor weight is reduced by 30%.

The high power capacity of humanoid robot is desired for application of running or jumping motions, and the new generation robot formulate the need for a low-mass high-torque motor. A frameless motor has been designed by the group, it is very important to calculate the thermal field of the motor and get the conclusion for the choice of the motor parameters. The magneto-thermal coupling analysis of the motor was carried out based on the thermal network by the iterative calculation. By using the equivalent thermal network method, the elements copper loss and core loss is coupled into elements in thermal analysis by keeping the same mesh structure between magnetic and thermal analysis. Other losses such as air friction loss, rotor loss are included in the model. A temperature rise calculation program was written and different position temperature distribution was obtained. In the meantime, the steady-state temperature of BLDC was calculated by using the finite element method (FEM). The experimental results show that, the actual torque performance of the motor can reach the target of our design, at last, temperature calculation results obtained from two different methods were compared with experimental data, and the correctness of the calculation model is verified.

The fixture that supports the binocular telescope should be highly precise. However, its thin and aluminum-alloy-made structure will reduce the strength and stiffness, which may result in deformations during the machining process. This, together with the complicated structure of the body, makes it difficult to determine the concrete positions of maximum stress and maximum deformation through traditional calculation methods. Therefore, Patran software is employed in the paper for pre-treatment and post-treatment, and Nastran software employed for analysis and calculation so as to analyze and optimize the stressed deformation of the workpiece in the fixture.

One very popular IoT system is characterized by the very bursty traffic in which the transmission occurrence can be as lower as just 200 milliseconds in multiple hours. The traditional Monte Carlo behavioral simulation is very time-consuming for a usual IoT system where the traffic burst is significantly smaller than the hibernation time and the number of terminals is big. Alternatives are analytical approaches using random probability and stochastic process theory, and there have been numerous papers on Slotted ALOHA (S-ALOHA) system. Unfortunately almost all the results obtained so far are based on full buffer traffic model so there is not an efficient approach to evaluate the system performance of an IoT system supporting massive number of terminals with very bursty traffic patterns. Two analytic methodologies are proposed and studied in this paper for very bursty traffic pattern in a contention based access system employing S-ALOHA access with Binary Exponential Back-off (BEB), and a set of closed-form formulae are derived. The first method is based on the probability modeling and the second method is a Markov chain based 2-D analytical model. The fundamental parameter in both methods is the expression for packet transmission probability, and the close-form expressions are derived for both methods. It was verified that the two expressions agree with each other very well. Based on the packet transmission probability, the close form expressions for other system performance indicators are also derived, which includes packet loss rate, transmission time, transmission delay, re-transmission times, collision possibility, and channel utilization efficiency. The proposed methods were verified to match real system performance very well, and they can be the efficient and accurate analytical tools for IoT system performance evaluation and optimization supporting very bursty traffic.

The limitations in achieving the goal of building the faster biomimetic robot are the torque produced from motors used to power the robot, as well as the mass and power dissipation of these motors. These limitations formulate the need for a low-mass high-torque motor. In order to improve the torque density of the motor, this paper outlines the electromagnetic design of a permanent magnet brushless DC motor with fractional slot concentrated winding that meet the goals of the robot while minimizing the total mass. The basis of the pole-slot numbers combination of the motor with fractional-slot concentrated windings is analyzed, and the magnetic fields of the motor which produced by permanent magnet and windings current are calculated on the basis of the permanent magnet field and airgap field. Moreover, finite element analysis for the motor is carried out to investigate the distribution of the magnetic field, back electromotive force, core loss, steady torque and cogging torque. The results prove the feasibility of the design method, and the torque density of the motor is 3.47Nm/kg.

When the dump is in lifting process, its cylinder bracket bear the whole lifting weight, so the bracket's rigidity and strength is very important, it has to be taken into consideration about the structure type in design in order to meet the requirements. It is very difficult to calculate the rigidity and strength of bracket by the traditional methods. The advanced method-finite element method is adopted in this paper, and the more simple and more reliable and higher quality products can be gotten by using multi-point constrained method of the finite-elements method.

In this paper, we consider the monotone measure identification issue from the perspective of the Shapley importance and interaction index, and propose Shapely importance and interaction index oriented monotone measure identification methods. We investigate some properties of the probabilistic interaction indices of the empty set, analyze the meaning of the Shapely interaction index of the empty set in the context of multicriteria decision analysis, and propose the maximum and minimum empty set interaction principles based monotone easure identification methods.

Online reputation has been proved to build trust and decrease uncertainty by prior studies with survey, panel, and experiment data. Aiming to directly measure reputation value, we adopted famous Becker-DeGroot-Marschack (BDM) auction procedure in economics to elicit subject's true willingness to pay (WTP) for product in a three-stage behavior experiment. The image of five-crown and five-heart, neither rating nor reviews, was extracted from Taobao.com to symbolize seller reputation. Data were analyzed in both behavioral and cognitive level. Bidding price and response time provided strong behavioral support to the relationship between seller symbol and reputation value. Data further indicated cognitive perception on seller symbol, which was measured by a psychometric scale of perceived reputation, impacted individual's WTP. Both behavior and cognitive results extended our understanding of reputation value.

This paper aims at the ineffective cases of HF radio interference within the operational distance from the sky-wave interference equipment, to put forward a conclusion that the Sporadic E-layer in the ionosphere can stop waves from arriving at the target radio by means of analysis of sky-wave propagation principles and the influencing factors between interference effects. Meanwhile, this paper puts forward ways to interfere the antenna due to different options of different distances and different heights of ionospheres, when the sky-wave interferes of the antenna radiation direction thus resolves the bad interference results caused by Sporadic E layer and testifies the conclusions through experiments as well through the study.

This paper contraposes issues related to modeling and control for swing nozzle, uses the methods of modeling and analysis, elaborates the research on fuzzy PID robust control for swing nozzle. In addition, swing nozzle servo system installation and other related issues, the influence of load torque and the analysis of the related processing on the swing nozzle are given. The computer simulation results show that the control scheme proposed in this paper fuzzy PID robust control can achieve a good result for swing nozzle servo system.

A completely scalable parallel algorithm, the Parallel Multi-Layer Hybrid Block (PMHB) method, is proposed to solve block-tridiagonal equations on parallel computers. PMHB has multi-layers of parallelism. The different parallel tridiagonal solvers can be choused on different layers for different applications. By choosing different solvers on different layers and controlling its multi-layer partition, PMHB can deliver better performance for different applications on different machine ensembles and problem sizes. Theoretical analyses and numerical experiments indicate that PMHB is an efficient and arbitrarily extensible method with multi-layer hybrid cycle reduction calculation. The method has been implemented on the “Zi-Qiang 3000” supercomputer of Shanghai University. The numerical results are the same with the theoretical analysis. Given the accuracy, the linear speedup rate is obtained, and parallel efficiency over 90 % is reached.

While the np chart is powerful for detecting large shifts in fraction nonconforming p, the synthetic chart is more effective for detecting small p shifts. In this article, the salient features of the np chart and synthetic chart are hybridized to produce the Syn-np chart. The results of the performance studies indicate that the new Syn-np chart significantly outperforms the np chart and synthetic chart by 73% and 31%, respectively, in terms of Average Number of Defectives (AND) across a wide range of p shifts under different circumstances.

Failure models with stochastic hazard rates provide more realistic and accurate characterization of systems failure behavior under dynamic and heterogeneous working environments. However, incorporation of stochastic hazard rates results in compound distribution involving integration over random variables, which generally does not have closed form solutions. Using Weibull models with gamma-distributed shape parameters as an example, this paper proposes a simulation-assisted method for estimation of failure models with stochastic hazard rates. A simulated log-likelihood function is constructed by approximating the compound failure distribution with statistical sampling. An algorithm based on differential evolution is subsequently developed to implement maximum likelihood estimation through optimization via simulation. The proposed simulation-assisted method has been tested to be accurate in model estimation based on numerical experiments using simulated data.

This paper proposes a novel way to incorporate the analytical hierarchy analysis into the genetic algorithm to solve the flow shop scheduling problem with reentrant jobs. The proposed approach allows the manufacturers take many criteria into consideration genetic algorithm gets the near-optimal sequence while the analytical hierarchy analysis assists to fulfill the multiple criteria as well as fasten the convergence that nested in the selection procedure. Initial population given by the genetic algorithm is filtered by the AHP so that the preferred chromosomes are kept as parents to generate the offspring. To demonstrate how the proposed approach works for the re-entrant flow shop scheduling, a case study of a repairing company whose jobs with dynamic re-entrant characteristic have been conducted. The experiments simulate the case scenario and the results indicate the superiority of proposed method over the practical approach. This finding is able to provide a solid foundation on which the scheduler can enhance the efficiency and accuracy of the re-entrant scheduling.