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Industrial robots are widely used in modern factories. Robot faults lead to the inevitable suspension of production lines. The prediction of robot failure can improve production capacity. However, it is challenging due to the variations of robots in dynamic working regimes. This paper presents a methodology of fault prognosis of industrial robots, including (1) a modeling approach of remaining useful life prediction using domain-generalization-adversarial long short-term memory to reduce the robot-to-robot variations, (2) an approach of two-stage health assessment based on principal component analysis-squared prediction error and p-chart that can reduce the disturbance of outliers in normal operations, and (3) a workflow containing feature extraction using wavelet packet decomposition, feature smoothing using exponential smoothing, feature normalization using z-score and feature selection using Pearson correlation coefficient. The case study of liquid crystal display transfer robots shows the methodology can effectively reduce the variations and improve the prediction of RUL.

In a single DC-DC converter, the conversion power was faced with the problems of large input and output current, great loss and serious EMI. So the method of series connection of multiple converter modules was often used, which could reduce the stress of the power device, improve the reliability and meet the requirements of different power. In this paper, we explored the control requirements and strategies of the IPOP three-level Buck converter. Combing the systematic models of IPOP DC-DC Buck converter, we constructed the Lyapunov energy function of relevant state variable, introduced a new formula of inductance current for the reference, built a feedback loop and reached the approximate steady-error and current balance for multi-output by matching the output variable parameter. In addition, system performance was analyzed through the small signal model built by state space method. Finally, it was proved effective through the simulation experiments.

The Catsper channel is a sperm-specific, Ca2+-permeable, pH-dependent, and low voltage-dependent channel that is essential for the hyperactivity of sperm flagellum, chemotaxis towards the egg, capacitation and acrosome reaction. All of these physiological events require calcium entry into sperm cells. Remarkably, Catsper genes are exclusively expressed in the testis during spermatogenesis, and are sensitive to ion channel-induced pH change, such as NHEs, Ca2+ATPase, K+ channel, Hv1 channel and HCO3 − transporters. Furthermore, the Catsper channel is regulated by some physiological stimulants, such as progesterone, cyclic nucleotides (e.g., cAMP, cGMP), zona pellucida (ZP) glycoproteins and bovine serum albumin (BSA). All of these factors normally stimulate Ca2+ entry into sperm through the Catsper channel. In addition, the Catsper channel may be a potential target for male infertility treatment or contraception. This review will focus on the structure, functions, regulation mechanisms and medicinal targets of the Catsper channel.

SWAT (Soil and Water Assessment Tool) model is one of distributed hydrological model, based on spatial data offered by GIS and RS. This article mainly introduces the SWAT model principle, structure, and it is the application of stream flow simulation in China and other countries, then points out the deficiency existing in the process of model research. In order to service in water resources management work better, experts and scholars further research the rate constant and uncertainty of the simplification of the model parameters, and the combination of RS and GIS to use, and hydrological scale problems.

In this article, by using the daily precipitation data measured at 58 meteorological stations, spatial and temporal variability of daily precipitation including zero rainfall values (called precipitation) and without zero rainfall values (called rain) and four precipitation extrema (P0, P20, P50, and P100 representing the daily precipitation with the magnitude smaller than 0.1 mm, bigger than 20 mm, 50 mm, and 100 mm per day, respectively) in the Yangtze River Delta (YRD) during 1958-2007 were analyzed, and the effects of urbanization were further investigated. Results indicate that (i) differing from the downward trends in 1958-1985, daily precipitation and rain in 1986-2007 show slowly downward trends in the mid YRD but show upward trends in the northern and southern YRD. (ii) Spatial and temporal variability of the rain is more complex than daily precipitation. Both of them become smaller but show more obvious fluctuations in 1986-2007. (iii) Urbanizations cause not only the urban rainfall island problem but also more obvious fluctuations of rain intensity in the mid YRD, reflecting more uncertainty of daily precipitation variability. (iv) Urbanizations have little effects on the variability of P0 and P100 but cause notable increases of P20 and P50. (v) The spatial variability of daily precipitation and precipitation extrema in 1958-1985 clearly shows a breakpoint at 30 degrees 20'N latitude, but the breakpoint disappears afterward because of the effects of urbanization. Copyright (C) 2012 John Wiley & Sons, Ltd.

New energy vehicles have bright prospect in the near future. In new energy vehicles some parts which are driven by engine through transmission will be replaced by electric drive, such as refrigeration compressor used for air conditioning and air compressor used for air brake system. Because of advantages, such as high efficiency, low friction, compact structure, and so on, linear compressor is suitable to solve above problems. In this paper a novel electric linear compressor is presented. Research work, such as simulation, structure design, control design, has been done. Further experiments are being done by my research team. We believe that electric linear compressor is worthy of being researched to popularize new energy vehicles.

Detection of abrupt change is a key issue for understanding the facts and trends of climate change, but it is also a difficult task in practice. The Mann-Kendall (MK) test is commonly used for treating the issue, while the results are usually affected by the correlation and seasonal characters and sample size of series. This paper proposes a discrete wavelet entropy-aided approach for abrupt change detection, with the temperature analyses in the Haihe River Basin (HRB) as an example. The results show some obviously abrupt temperature changes in the study area in the 1960s-1990s. The MK test results do not reflect those abrupt temperature changes after the 1980s. Comparatively, the proposed approach can detect all main abrupt temperature changes in HRB, so it is more effective than the MK test. Differing from the MK test which only considers series' value order or the conventional entropy which mainly considers series' statistical random characters, the proposed approach is to describe the complexity and disorderliness of series using wavelet entropy theories, and it can fairly consider series' composition and characteristics under different scales, so the results can more accurately reflect not only the abrupt changes, but also the complexity variation of a series over time. However, since it is based on the entropy theories, the series analyzed must have big sample size enough and the sampling rates being smaller than the concerned scale for the accurate computation of entropy values.

The focus of this paper is dynamic link allocation algorithms for sharing the limited link resources of the tracking and data relay satellites (TDRS) system among many burst users with varying quality of service (QoS) requirements. The task of scheduling communications between TDRS link and spacecraft is getting more and more critical since an increasing number of spacecraft must communicate with ground station by the TDRS. In such a congested scenario, the current practice, in which experts build hand-made schedules, often leaves a large number of communication requests un-served. This paper proposes a tight time-indexed formulation of the problem to include several complex technological constraints. A genetic algorithm is then devised which provides near-optimal solutions of a set of large-scale test problems arising in the TDRS-spacecraft constellation. As the simulation result, the genetic algorithm shows numerical stability and robustness adequate for practical implementation.

Space network are now become a very important and necessary complementary to the ground networks, it will extend the terrestrial Internet networks to space. However, there are still many challenges exist before the space-ground integrated networks come true, and how to transport data reliably in space networks is the very difficult one among these challenges. TCP has been a robust and efficient transport layer protocol for terrestrial networks, but it does not fare very well in the space environment because of the long-link delay, high bit-error-rate, etc, compare with the terrestrial networks. However, it does provide an excellent base for extension. One of the attempts to improve transport layer performance in space networks has been the development of SCPS-TP, which is a popular modification of TCP that is very efficient for space environments. In this paper we compare the performance of TCP and our implementation of SCPS-TP SNACK (Selective Negative Acknowledgement) over paths with different BER and different delays. Our goal is to determine the improvement in throughput and link utilization when the SCPS-TP SNACK instead of standardized TCP mechanisms are used. The results show that SCPS-TP has a better performance than the regular TCP in space communication.

The design and development of future ground-space integrated networks is one of the hot issues in space technology nowadays because of the long-link delay, high bit-error-rate, asymmetric bandwidth, intermittent links compare with the terrestrial networks. The focus of this paper is to design topology for this hybrid networks with space segments, select appropriate protocols for it and analyze its performance at the same time. The paper does research on these problems based on IP technology of the ground network and CCSDS protocol that special for space communication, proposes an topology to integrate the space network and the ground network using a new mode, that is IP over CCSDS AOS mode; then it designs a data transmission configuration and protocol stack model for the ground/space hybrid network, in the end, the paper analyses the performance of this configuration in the hybrid networks. The results show that the topology and the transmission configuration proposed by the paper have a better performance than the regular configuration and worth to be applied.

The peculiar nova-like star PU Vul was observed spectroscopically from 1981 Sept 12 to 1983 Dec 11 at Yunnan Observatory and Beijing Observatory. In 1981 Sept, the star showed an absorption spectrum of the Balmer lines, the H,K and D lines, and some FeII, SrII and TiII lines. Hα was seen in emission in 1982 Oct and Hβ, in 1983 Sept. Both emissions were enhanced in 1983 Oct. and then dimmed since 1983 Nov. On 1983 Dec 11, Hβ might be absent, but the Hα was still visible. The spectral type was similar to that of an F giant during this period. This object may be an exceptionally slow nova and a binary consisting of an M giant and a hot companion.