49 research outputs found

    Power allocation for D2D communications using max-min message-passing algorithm

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    The approach of factor-graphs (FGs) is applied in the context of power control and user pairing in Device-to-Device (D2D) communications as an effective underlay concept in wireless cellular networks. D2D communications can increase the spectral efficiency of wireless cellular networks by establishing a direct link between devices with limited help from the evolved node base stations (eNBs). A well-designed user pairing and power allocation scheme with low complexity can remarkably improve the system’s performance. In this paper, a simple and distributed FG based approach is utilized for power control and user pairing implementation in an underlay cellular network with D2D communications. A max-min criterion is proposed to maximize the minimum rate of all active users in the network, including the cellular and multiple D2D co-channel links in the uplink direction. An associated message-passing (MP) algorithm is presented to distributedly solve the resultant NP-hard maximization problem, with a guaranteed convergence compared to game-theoretic and Q-learning based methods. The complexity and convergence of the proposed method are analyzed and numerical results confirm that the proposed scheme outperforms alternative algorithms in terms of complexity, while keeping the sum-rate of users nearly the same as centralized counterpart methods

    Real-time Dynamic Object Detection for Autonomous Driving using Prior 3D-Maps

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    International audienceLidar has become an essential sensor for autonomous driving as it provides reliable depth estimation. Lidar is also the primary sensor used in building 3D maps which can be used even in the case of low-cost systems which do not use Lidar. Computation on Lidar point clouds is intensive as it requires processing of millions of points per second. Additionally there are many subsequent tasks such as clustering, detection, tracking and classification which makes real-time execution challenging. In this paper, we discuss real-time dynamic object detection algorithms which leverages previously mapped Lidar point clouds to reduce processing. The prior 3D maps provide a static background model and we formulate dynamic object detection as a background subtraction problem. Computation and modeling challenges in the mapping and online execution pipeline are described. We propose a rejection cascade architecture to subtract road regions and other 3D regions separately. We implemented an initial version of our proposed algorithm and evaluated the accuracy on CARLA simulator

    A rate-compatible puncturing scheme for finite-length LDPC Codes

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    In this paper, we propose a rate-compatible puncturing scheme for finite-length low-density parity-check (LDPC) codes over the additive white Gaussian noise (AWGN) channel. The proposed method is applicable to any LDPC mother code, both regular and irregular, and constructs punctured codes which perform well in both the waterfall and the error floor regions for a wide range of code rates. The scheme selects code bits to be punctured one at a time and based on a sequence of criteria. An important selection criterion is the number of short cycles with low approximate cycle extrinsic message degree (ACE) in which a candidate bit node participates. Simulation results demonstrate that the ACE measure, which is most often the determining criterion in the final selection of the puncturing candidates, plays an important role in improving the performance of the codes in both the waterfall and the error-floor regions. These results also demonstrate that the proposed scheme is superior to the existing puncturing methods, particularly when a wide range of code rates is desirable

    Expression and functional analysis of recombitant scFv and diabody fragments with specificity for human RhD

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    n an attempt to generate recombinant anti-D reagents for possible diagnostic and therapeutic use we cloned the genes encoding the variable (V) domains of a human anti-D antibody secreted by the lymphoblastoid cell line BTSN4. A single-chain Fv (scFv) fragment was constructed using a 21 amino acid linker to join the genes encoding the variable domains of the BTSN4 heavy (VH) and light chains (VL). A diabody construct was also generated by reducing the length of the scFv linker from 21 to 10 residues. The scFv and diabody constructs were cloned into the pFLAG-CTS vector, expressed in E. coli host cells and the recombinant proteins were affinity-isolated from bacterial culture medium. Analysis of the recombinant proteins indicated that they retained the D antigen binding specificity of the parental BTSN4 IgG. Furthermore, both fragments mediated agglutination of papain-treated D positive erythrocytes in the absence of a cross-linking second antibody. While the agglutinating property of BTSN4 diabody was readily explained by the noncovalent association of this protein as a bivalent dimer, oligomeric forms of BTSN4 scFv were not detected when the protein was analysed by size exclusion chromatography. Thus, the agglutinating property of the scFv is not the result of the formation of non-covalently associated multimeric forms of the antibody fragmen

    Approximation of log-likelihood ratio for wireless channels based on Taylor series

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    A new approach for the approximation of the channel log-likelihood ratio (LLR) for wireless channels based on Taylor series is proposed. The approximation is applied to the uncorrelated flat Rayleigh fading channel with unknown channel side information at the receiver. It is shown that the proposed approximation greatly simplifies the calculation of channel LLRs, and yet provides results almost identical to those based on the exact calculation of channel LLRs. The results are obtained in the context of iterative decoding of low-density parity-check (LDPC) codes and include threshold calculations and error rate performance of finite-length codes. Compared to the existing approximations, the proposed method is either significantly less complex, or considerably more accurate

    Lowering the error floor of LDPC codes using cyclic liftings

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    Cyclic liftings are proposed to lower the error floor of low-density parity-check (LDPC) codes. The liftings are designed to eliminate dominant trapping sets of the base code by removing the short cycles which are part of the trapping sets. We derive a necessary and sufficient condition for the cyclic permutations assigned to the edges of a cycle ξ of length ℓ(ξ) in the base graph such that the inverse image of ξ in the lifted graph consists of only cycles of length strictly larger than ℓ(ξ). The proposed method is universal in the sense that it can be applied to any LDPC code over any channel and for any iterative decoding algorithm. It also preserves important properties of the base code such as degree distributions, and in some cases, the code rate. The constructed codes are quasi-cyclic and thus attractive from a practical point of view. The proposed method is applied to both structured and random codes over the binary symmetric channel (BSC). The error floor improves consistently by increasing the lifting degree, and the results show significant improvements in the error floor compared to the base code, a random code of the same degree distribution and block length, and a random lifting of the same degree. Similar improvements are also observed when the codes designed for the BSC are applied to the additive white Gaussian noise (AWGN) channel

    High-intensity interval training lowers blood pressure and improves apelin and NOx plasma levels in older treated hypertensive individuals

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    Hypertension is the major risk factor for cardiovascular diseases and is one of the primary causes of morbidity and mortality worldwide. Apelin levels and NO bioavailability are impaired in older hypertensive patients. Exercise is an effective intervention for treating hypertension. Our purpose was to evaluate the effect of high-intensity interval training on blood pressure, apelin, and NOx plasma levels in older treated hypertensive individuals. Thirty treated hypertensive subjects (61.70 ± 5.78 years, 17 males, 13 females) were randomly divided into 6 weeks of high-intensity interval training (n = 15) and control (n = 15). The exercise training was conducted for three 35-min sessions a week (1.5-min interval at 85�90 of heart rate reserve HRR and 2 min active phase at 50�55% of HRR). Assessment of plasma apelin, nitrite/nitrate (NOx), and endothelin-1 (ET-1) was performed before and after the intervention. At the end of the study, apelin, and NOx plasma levels increased significantly in the high-intensity interval training (HIIT) group (P = 0.021, P = 0.003, respectively). Conversely, ET-1 plasma levels significantly decreased in the training group after the intervention (P = 0.015). Moreover, there was a positive correlation between the change of plasma apelin and change of plasma NOx (r = 0. 771, P = 0.0008). In addition, there was a negative correlation between the change of plasma ET-1, change of plasma apelin (r = � 0.595, P = 0.019), and variation of NOx (r = � 0.572, P = 0.025). This study indicates that, by increasing of apelin and NOx plasma levels, HIIT may be effective in reducing blood pressure. © 2017, University of Navarra

    Life quality of cancer patient with or without self awareness

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    Background and Objective: Disclosure of cancer is one the main challenges in caring of patients with cancer, since it may have adverse effects on the patients quality of life. This study was done to determine life quality of cancer patient with or without self awareness. Materials and Methods: This case – control study was conducted on 300 cancer patients in Shahid Ghazi-Tabatabaei hospital in Tabriz, Iran during 2009. The cancer patients included 150 subjects aware of their cancer diagnosis as cases and 150 unaware patients as controls. The patient's quality of life was assessed Using EORTC QLQ-C30 questionnaire. Data were analyzed using SPSS-17 and student’s t-test. Results: The mean±SD of quality of life among aware and unaware patients were 64.18±18.85 and 65.16±19.02, respectively. There was no significant difference of quality of life between two groups. Life social dimension in unaware patients significantly was more than aware patients (P<0.05). Conclusion: Patients awareness of cancer have no effect on their quality of life
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