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1

Efficient learning variable impedance control for industrial robots

Li C., Zhang Z., Xia G., Xie X., Zhu Q.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2019

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Vol. 67, nr 2

201--212

EN

Compared with the robots, humans can learn to perform various contact tasks in unstructured environments by modulating arm impedance characteristics. In this article, we consider endowing this compliant ability to the industrial robots to effectively learn to perform repetitive force-sensitive tasks. Current learning impedance control methods usually suffer from inefficiency. This paper establishes an efficient variable impedance control method. To improve the learning efficiency, we employ the probabilistic Gaussian process model as the transition dynamics of the system for internal simulation, permitting long-term inference and planning in a Bayesian manner. Then, the optimal impedance regulation strategy is searched using a model-based reinforcement learning algorithm. The effectiveness and efficiency of the proposed method are verified through force control tasks using a 6-DoFs Reinovo industrial manipulator.

2

Establishment of a rapid method to quantify eight flavonol glycosides for quality assessment of red toon using UPLC

Shen Y., Xu M., Deng P., Gu Q., Yin H., Xia G., Jia X., Yang H., Tam J.

Acta Chromatographica

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2018

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Vol. 30, no. 1

31--37

EN

Red Toon is a popular vegetable of favorable health benefits over Asia and Russia regions. In this study, isolation and identification of chemical constituents were performed to assess the quality of this functional food cultivated in various origins or harvested in different months. As a result, eight flavonol glycosides including rutin (I), myricitrin (II), quercetin-3-O-β-d-galactoranoside (III), quercetin-3-O-β-d-glucopyranose (IV), quercetin-3-O-α-l-arabinopyranoside (V), astragalin (VI), quercetin-3-O-α-l-rhamopyranoside (VII), and kaempferol-3-O-α-l-rhamopyranoside (VIII) were obtained. Among these, compounds III and V were isolated from Toona genus for the first time. Importantly, a rapid and convenient ultra-performance liquid chromatography (UPLC) method was developed to quantify the flavonol glycosides in Red Toon and validated for linearity, precision, stability, repeatability, and accuracy successively. In addition, it was found that total flavonoid glycosides (about 2.6%) in the food were kept at a higher level from April to June than other months of the year. Furthermore, their content in the Red Toon collected from ten different origins was also determined and compared, and the results suggested that the total flavonoid glycosides from Shandong Yantai were the highest, followed by Shandong Ximou, supporting a well-recognized viewpoint that Red Toon cultivated in Shandong Province, China, is considered genuine due to the best health benefits and flavor.

3

Isolation of gallic acid and methyl gallate from folium Toonea Sinensis and validated method for their quantitation using LC-based technologies

Shen Y., Yang H., Xia G., Wang J., Cai B., Jia X.

Acta Chromatographica

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2013

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Vol. 25, no. 4

687--701

EN

Silica-gel column chromatography and preparative reversed-phase high-performance liquid chromatography (RP-HPLC) were sequentially employed for the isolation of two antioxidants including gallic acid and methyl gallate from Folium Toonea Sinensis. An RP-HPLC-UV method was then developed and validated to rapidly determine their content in this herb with ethyl gallate as internal standard. The quantitation was performed on an XBridge Shield RP18 column (150 mm × 4.6 mm, 5 μm) under 40°C. The mobile phase consisting of acetonitrile and 0.1% formic acid aqueous solution was driven at 1.0 mL min -1 under gradient elution, and 270 nm was selected to monitor the separation. To evaluate the fitness for purpose of the method and to investigate the difference in the content of analytes among different samples, the leaves collected from five production sites were analyzed. The newly established method is suitable for routine analysis of gallic acid and methyl gallate in the herb and, hence, can assist in its quality assessment. It was also found that not only the content of two antioxidants but also the ratio varied significantly among different geographical origins. In addition, three samples from Yantai, Zumadian, and Zhenjiang were distinguished as they have a much higher content ratio than the other two.

4

Two-Echelon Reservoir Inventory Management with Forecast Updates: Perspective from Operations of Multireservoir in Interbasin Water Diversion Projects

Xu Y., Wang L., Chen Z., Xia G., Yang Y.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 9b

84-91

EN

We consider a finite-horizon, periodic-review inventory model with inflow forecasting updates following the martingale model of forecast evolution (MMFE) in multiresevoirs. This model introduces a new method of determining an operating policy in which the policy is based on the dynamic programming (DP) model with a physical equation and a recursive equation. It adequately considers the internal relationship among multireservoirs in inter-basin water diversion projects (IBWDP) and calculates the expected benefits from future operation. The stochastic nature of the inflow is taken into account by considering the correlation between the streamflows of each pair of consecutive time intervals based on MMFE. According to interdependence, the probability of transition from a given state or stage to its succeeding ones can be calculated. Finally, to assess the effectiveness of the policies, the model is compared with other model and is applied to the Chinese South-North Water Diversion project.

PL

Analizowano model okresowej inwentaryzacji wraz z przewidywaniem nawodnienia w systemie wielu rezerwuarów. Wprowadzono programowanie dynamiczne uwzględniające wewnętrzne relacje między rezerwuarami w dywersyjnych projektach wodnych. Model sprawdzono na przykładzie chińskiego projektu systemu wodnego północ-południe.

5

Output characteristics of weak-coupling fiber grating external cavity semiconductor

Zhou H., Xia G., Fan Y., Deng T., Wu Z.

Opto-Electronics Review

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2005

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Vol. 13, No. 1

27--30

EN

After taking into account the contribution of fiber grating to the phase condition, the mode distribution of fiber grating external cavity semiconductor laser (FGESL) has been determined, and the output characteristics of weak-coupling fiber grating external cavity semiconductor laser (WCFGESL) have been investigated theoretically through solving the multi-mode rate equations numerically. The results show that with increase in the injected current, the lasing wavelength of WCFGESL appears fluctuation, whose amplitude is influenced by the external cavity length to a certain degree, the side mode suppression ratio (SMSR) increases accompanied by an oscillation, and the P-I curve distorts slightly. All these theoretical estimations accord with the reported experimental observations.

6

Theoretical study on wavelength conversion using cross-polarization modulation in a single semiconductor optical amplifier

Wang F., Xia G., Wu Z.

Optica Applicata

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2005

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Vol. 35, nr 2

365-375

EN

Wavelength conversion based on the cross-polarization modulation (XPM) in a single semiconductor optical amplifier (SOA) has been numerically investigated by using the theoretical model in which the birefringence has been taken into account. The results show that the non-inverted and inverted wavelength conversion can be realized through selecting reasonably the parameters; there exit some differences in the chirp, extinction ratio (ER), and eye diagram of the converted signal between the non-inverted and inverted conversion; with the increase of the bit rate, the chirp increases and the eye opening ratio (EOR) decreases.