488 research outputs found

    CCD photometric study of the W UMa-type binary II CMa in the field of Berkeley 33

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    The CCD photometric data of the EW-type binary, II CMa, which is a contact star in the field of the middle-aged open cluster Berkeley 33, are presented. The complete R light curve was obtained. In the present paper, using the five CCD epochs of light minimum (three of them are calculated from Mazur et al. (1993)'s data and two from our new data), the orbital period P was revised to 0.22919704 days. The complete R light curve was analyzed by using the 2003 version of W-D (Wilson-Devinney) program. It is found that this is a contact system with a mass ratio q=0.9q=0.9 and a contact factor f=4.1f=4.1%. The high mass ratio (q=0.9q=0.9) and the low contact factor (f=4.1f=4.1%) indicate that the system just evolved into the marginal contact stage

    Design and test of a pneumatic precision metering device for wheat

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    The objective of this study was to apply the precision metering on wheat seeding to overcome seed damage, seed loss and non-uniform distribution.  Accordingly, a prototype of the pneumatic precision metering device for wheat was developed.  The performance of the device, including quality of feed index (QFI), multiple index (MULI), miss index (MISI) and seed rate expressed in number of kernels per meter length (KPM), was investigated under laboratory conditions in Wuhan using a test stand with camera system.  The results revealed that the rotating speed (RS) and negative pressure (NP) and their interactions had a significant effect on these variables.  The maximum QFI (92.98%) was obtained at rotating speed of 19.0 rpm and negative pressures of 2.5 kPa with MULI and MISI of 2.01% and 5.09%, respectively.  However, the seed rate (KPM) was less than the recommended compared to previous hypothesis.  The best seed rate was 53 KPM producing QFI of 89.11% with MULI and MISI of 9.00% and 1.88%, respectively at rotating speed of 34 rpm and negative pressure of 4.5 kPa.  The recommended seed rates estimated at 40 KPM and 53 KPM for 12 cm and 15 cm row spacing respectively were achieved at a range of RS and NP with QFI ranging between 84.57 to 89.11%.  The study demonstrated that wheat could be seeding within an acceptable precisely range by pneumatic precision metering device. Keywords: wheat, experiments, performance indices, pneumatic precision metering device

    Dynamic analysis for kernel picking up and transporting on a pneumatic precision metering device for wheat

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    The objective of this study was to theoretically investigate the factors affecting kernels during picking up and transporting stage using a pneumatic precision metering device designed especially for wheat precision seeding and correlates findings with the results from practical testing under laboratory conditions using a test stand with camera system.  The results from dynamic analysis were found to be corresponding with that of the laboratory testing.  The findings revealed that the performance indices, such as quality of feed index (QFI), multiple index (MULI) and miss index (MISI), were obviously influenced by changing the negative pressure force FQ and rotating speed ω.  The result from test stand highlighted that when the negative pressure increased the QFI increased, MULI increased and MISI decreased, however, the QFI decreased and MISI increased with increasing the rotating speed.  The dynamic analysis likewise revealed that increasing the friction index tanαg by choosing a suitable material with high friction angle αg for seed plate as well as enlarging the seed hole diameter could improve the efficiency of the negative pressure force FQ.   Keywords: wheat, kernel, picking up, transportation, dynamic model, precision metering devic

    Power allocation for D2D communications in heterogeneous networks

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    In this paper, we study power allocation for D2D communications in heterogeneous networks utilizing game theory approach to improve the performance of the whole system. Given D2D's underlay status in the system, Stackelberg game framework is well suited for the situation. In our scheme, macrocell system and femtocell system are considered as two leaders and D2D pairs are considered as the follower, forming a two-leader-one-follower Stackelberg game. The leaders act first, charging some fees from the follower for using the channel and causing interference to jeopardize their communication equality. The follower observes the leaders' behavior and develops its strategy based on the prices offered by the leaders. We analyse the procedure and obtain the Stackeberg equilibrium, which determines the optimal prices for the leaders and optimal transmit power for the follower. In the end, simulations are executed to validate the proposed allocation method, which significantly improves data rate of user equipments. ? 2014 Global IT Research Institute (GIRI).EICPCI-S(ISTP)

    Integrating the Symmetry Image and Improved Sparse Representation for Railway Fastener Classification and Defect Recognition

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    The detection of fastener defects is an important task for ensuring the safety of railway traffic. The earlier automatic inspection systems based on computer vision can detect effectively the completely missing fasteners, but they have weaker ability to recognize the partially worn ones. In this paper, we propose a method for detecting both partly worn and completely missing fasteners, the proposed algorithm exploits the first and second symmetry sample of original testing fastener image and integrates them for improved representation-based fastener recognition. This scheme is simple and computationally efficient. The underlying rationales of the scheme are as follows: First, the new virtual symmetrical images really reflect some possible appearance of the fastener; then the integration of two judgments of the symmetrical sample for fastener recognition can somewhat overcome the misclassification problem. Second, the improved sparse representation method discarding the training samples that are “far” from the test sample and uses a small number of samples that are “near” to the test sample to represent the test sample, so as to perform classification and it is able to reduce the side-effect of the error identification problem of the original fastener image. The experimental results show that the proposed method outperforms state-of-the-art fastener recognition methods
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