2,220 research outputs found

    An integrated system for ultra-precision machine tool design in conceptual and fundamental design stage

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    This paper presents an integrated system used for ultra-precision machine tool (UPMT) design in conceptual and fundamental design stage. This system is based on the dynamic, thermodynamic, and error budget theories. The candidate configurations of the machine tool are first selected from the configuration library or a novel configuration designed by the user, according to the functions of the machine tool expected to realize. Then, the appropriate configuration is given by comparing the stiffness chain, dynamic performance, thermal performance, and the error budget of each candidate configuration. Consequently, the integrated design system enables the conceptual and fundamental of the UPMT to be designed efficiently with a theoretical foundation. The proposed system was used for several UPMT designs, which demonstrate the effectiveness of the integrated design system

    Pyrolysis gas as a carbon source for biogas production via anaerobic digestion

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    Carbon is an important resource for anaerobes to enhance biogas production. In this study, the possibility of using simulated pyrolysis gas (SPG) as a carbon source for biogas production was investigated. The effects of stirring speed (SS), gas holding time (GHT), and H2 addition on biomethanation of SPG were evaluated. The diversity and structure of microbial communities were also analyzed under an illumina MiSeq platform. Results indicated that at a GHT of 14 h and an SS at 400 rpm, SPG with up to 64.7% CH4could be bio-upgraded to biogas. Gas–liquid mass transfer is the limitation for SPG biomethanation. For the first time, it has been noticed that the addition of H2 can bioupgrade SPG to high quality biogas (with 91.1% CH4). Methanobacterium was considered as a key factor in all reactors. This study provides an idea and alternative way to convert lignocellulosic biomass and solid organic waste into energy (e.g., pyrolysis was used as a pretreatment to produce pyrolysis gas from biomass, and then, pyrolysis gas was bioupgraded to higher quality biogas via anaerobic digestion)

    L dwarfs detection from SDSS images using improved Faster R-CNN

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    We present a data-driven approach to automatically detect L dwarfs from Sloan Digital Sky Survey(SDSS) images using an improved Faster R-CNN framework based on deep learning. The established L dwarf automatic detection (LDAD) model distinguishes L dwarfs from other celestial objects and backgrounds in SDSS field images by learning the features of 387 SDSS images containing L dwarfs. Applying the LDAD model to the SDSS images containing 93 labeled L dwarfs in the test set, we successfully detected 83 known L dwarfs with a recall rate of 89.25% for known L dwarfs. Several techniques are implemented in the LDAD model to improve its detection performance for L dwarfs,including the deep residual network and the feature pyramid network. As a result, the LDAD model outperforms the model of the original Faster R-CNN, whose recall rate of known L dwarfs is 80.65% for the same test set. The LDAD model was applied to detect L dwarfs from a larger validation set including 843 labeled L dwarfs, resulting in a recall rate of 94.42% for known L dwarfs. The newly identified candidates include L dwarfs, late M and T dwarfs, which were estimated from color (i-z) and spectral type relation. The contamination rates for the test candidates and validation candidates are 8.60% and 9.27%, respectively. The detection results indicate that our model is effective to search for L dwarfs from astronomical images.Comment: 12 pages, 10 figures, accepted to be published in A

    Electric-field-induced phase transition of <001> oriented Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals

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    oriented 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 single crystals were poled under different electric fields, i.e. Epoling=4 kV/cm and Epoling=13 kV/cm. In addition to the temperature-dependent dielectric constant measurement, X-ray diffraction was also used to identify the poling-induced phase transitions. Results showed that the phase transition significantly depends on the poling intensity. A weaker field (Epoling=4 kV/cm) can overcome the effect of random internal field to perform the phase transition from rhombohedral ferroelectric state with short range ordering (microdomain) FESRO to rhombohedral ferroelectric state with long range ordering (macrodomain) FElRO. But the rhombohedral ferroelectric to tetragonal ferroelectric phase transition originating from to polarization rotation can only be induced by a stronger field (Epoling=13 kV/cm). The sample poled at Epoling=4 kV/cm showed higher piezoelectric constant, d33>1500 pC/N, than the sample poled at Epoling=13 kV/cm.Comment: 7 pages, 2 figure

    Bio-Inspired Autonomous Learning Algorithm With Application to Mobile Robot Obstacle Avoidance

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    Spiking Neural Networks (SNNs) are often considered the third generation of Artificial Neural Networks (ANNs), owing to their high information processing capability and the accurate simulation of biological neural network behaviors. Though the research for SNNs has been quite active in recent years, there are still some challenges to applying SNNs to various potential applications, especially for robot control. In this study, a biologically inspired autonomous learning algorithm based on reward modulated spike-timing-dependent plasticity is proposed, where a novel rewarding generation mechanism is used to generate the reward signals for both learning and decision-making processes. The proposed learning algorithm is evaluated by a mobile robot obstacle avoidance task and experimental results show that the mobile robot with the proposed algorithm exhibits a good learning ability. The robot can successfully avoid obstacles in the environment after some learning trials. This provides an alternative method to design and apply the bio-inspired robot with autonomous learning capability in the typical robotic task scenario

    Pengaruh Kompetensi, Pengembangan Karir, Pendidikan Dan Pelatihan (Diklat) Terhadap Knerja Pegawai Direktorat Jenderal Perimbangan Keuangan

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    . The success of the organization in achieving its goals supported by factors internaland external to the organization, where the internal side of the organization should be get firstattention to achieve maximum performance. This study aims to determine the effect ofcompetency, career development and training on employee performance of the DirectorateGeneral of Fiscal Balance, Ministry of Finance. The method used is descriptive quantitative.The data used are primary data collected by questionnaire and also secondary data. Thepopulation in this study were all employees as many as 387 people. The samples are taken byrandom sampling technique, using the Slovin‟s formula to take 80 people for samples. Thevariables in this study consisted of independent variables that are competency, careerdevelopment and training, while the dependent variable is the performance of employees. Thevariable measured with Likert Scale and hypothesis testing using multiple linear regression byusing t test and F test.Results of this study concluded that: 1) in partially competency hadpositive and significant impact on employee performance; 2) in partially career developmentprovide uneffect on employee performance; 3) in partially training had positive andsignificant impact on employee performance; and 4) in simultaneously competency, careerdevelopment and training have positive and significant impact on employee performance.Competency is the most influence variable on employee performance

    Satisfactory short-term outcomes of totally laparoscopic ileostomy reversal compared to open surgery in colorectal cancer patients

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    BackgroundRecently, totally laparoscopic (TLAP) surgery has suggested its potential on ileostomy reversal. This study aimed to compare the short-term outcomes between TLAP and traditional open ileostomy reversal.Patients and methodsFrom September 2016 to September 2021, 107 eligible patients underwent TLAP (n = 48) or open (n = 59) loop ileostomy reversal were retrospectively enrolled. Surgical parameters, postoperative recovery and complications were identified and compared between TLAP technique vs. open surgery.ResultsThe operation time and estimated blood loss showed no obvious difference between TLAP and open group. However, TLAP reversal significantly decreased the incision length (4.5cm vs. 6cm, P &lt; 0.001). Furthermore, patients underwent TLAP surgery showed quicker first ground activities (1 day vs. 2 days, P &lt; 0.001), faster first flatus passage (2 days vs. 3 days, P = 0.004) and shorter postoperative stay (5 days vs. 7 days, P = 0.007). More importantly, postoperative complications were significantly reduced after TLAP reversal (3 cases vs. 10 cases, P = 0.026). Further logistic regression analyses also indicated the TLAP technique was associated with lower incidence of complications (OR=3.316, CI, 1.118–9.835; P = 0.031).ConclusionsTLAP surgery is competitive in promoting postoperative recovery as well as reducing complications compared to the traditional open ileostomy reversal
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