Unambiguous Sine-phased BOC(kn,n) Signal Acquisition Based on Combined Correlation Functions

Galileo and GPS have been developing their new signals in recent years. Multiplexed Binary Offset Carrier (MBOC) is the final implementation of Galileo E1 and GPS L1C, which is the multiplexing of BOC(1,1) and BOC(6,1). Therefore, it is helpful to satisfy the demand that the new signals must be compatible with GPS BPSK signal. BOC(kn,n) modulation will provide better track performance and higher positioning accuracy. However, the main drawback of the BOC modulated signal is that its autocorrelation has multiple side peaks around the main peak. This paper will focus on a family of signals: sine-phased BOC(kn,n). We are trying to explore a new method to cancel the side peaks of BOC(kn,n) autocorrelation, making use of two kinds of correlation functions. One is the correlation of the incoming signal and the sine-phased BOC(kn,n) modulated spreading code(PRN code multiplied by subcarrier), and the other is the correlation of the incoming signal and the PRN code only. Two kinds of correlation function are separated into several sub-correlations. Sub-correlations have less side peaks which are in different code delays. Corresponding parts of two sub-correlations will be combined to cancel the side peaks separately, and finally the new function without side peaks will be acquired after several correlations added together. Simulation results will be given. It is shown that the proposed method is contributed to the side peaks cancellation for unambiguous sine-phased BOC (kn, n) signal acquisition

Unambiguous Acquisition for Galileo E1 OS Signal Based on Delay-And-Multiply

Galileo E1 Open Service (OS) signal is transmitted with the modulation of Composite Binary Offset Carrier (CBOC). CBOC has a main drawback that is the autocorrelation function has multiple side-peaks, which will lead to ambiguous acquisition. The high rate of data bit and secondary code makes it very difficult to increase coherent integration time. This paper will propose a new scheme based on the delay-and-multiply concept. And also this scheme combines the data channel and pilot channel. Finally, the theoretical results will be given to prove that the new scheme will accomplish unambiguous acquisition and also eliminate the influence of bit transition

Individual Building Rooftop and Tree Crown Segmentation from High-Resolution Urban Aerial Optical Images

We segment buildings and trees from aerial photographs by using superpixels, and we estimate the tree’s parameters by using a cost function proposed in this paper. A method based on image complexity is proposed to refine superpixels boundaries. In order to classify buildings from ground and classify trees from grass, the salient feature vectors that include colors, Features from Accelerated Segment Test (FAST) corners, and Gabor edges are extracted from refined superpixels. The vectors are used to train the classifier based on Naive Bayes classifier. The trained classifier is used to classify refined superpixels as object or nonobject. The properties of a tree, including its locations and radius, are estimated by minimizing the cost function. The shadow is used to calculate the tree height using sun angle and the time when the image was taken. Our segmentation algorithm is compared with other two state-of-the-art segmentation algorithms, and the tree parameters obtained in this paper are compared to the ground truth data. Experiments show that the proposed method can segment trees and buildings appropriately, yielding higher precision and better recall rates, and the tree parameters are in good agreement with the ground truth data

A frequency-offset estimation algorithm combines code and time features for the remote reception of a weak satellite signal

Remote control technology has greatly expanded the intelligence and automation of industry. Satellite signals are important to keep in contact with the facilities and devices in remote areas. However, satellite channels suffer from multi-scale attenuation to achieve reliable communications, which cannot provide sufficient accuracy and suitable complexity for the frequency-offset estimation of a weak signal. Therefore, this paper focused on a frequency-offset estimation method for a weak signal from a distant, poor satellite channel. First, we built a model of a distant satellite channel with mirror power reflection, considering large fading and multi-path fading simultaneously. Second, we described M-Walsh pilots and a signal vector matrix as they relate to satellite signals. Initially, we analysed the performance of different frequency-offset estimation methods in the satellite environment as opposed to the ground environment. We proposed compact M-Walsh pilots locking correlation to improve the estimation accuracy, which enhanced the frequency tracking. We further proposed equivalent weighting estimation allocation to help improve the balance of accuracy and complexity in the algorithm. Simulations and tests demonstrated that the new algorithm enhanced the root-mean-square-error frequency-offset estimate by 36.2% and the bit-to-error rate) performance by 29.5%

A frequency-offset estimation algorithm combines code and time features for the remote reception of a weak satellite signal

Remote control technology has greatly expanded the intelligence and automation of industry. Satellite signals are important to keep in contact with the facilities and devices in remote areas. However, satellite channels suffer from multi-scale attenuation to achieve reliable communications, which cannot provide sufficient accuracy and suitable complexity for the frequency-offset estimation of a weak signal. Therefore, this paper focused on a frequency-offset estimation method for a weak signal from a distant, poor satellite channel. First, we built a model of a distant satellite channel with mirror power reflection, considering large fading and multi-path fading simultaneously. Second, we described M-Walsh pilots and a signal vector matrix as they relate to satellite signals. Initially, we analysed the performance of different frequency-offset estimation methods in the satellite environment as opposed to the ground environment. We proposed compact M-Walsh pilots locking correlation to improve the estimation accuracy, which enhanced the frequency tracking. We further proposed equivalent weighting estimation allocation to help improve the balance of accuracy and complexity in the algorithm. Simulations and tests demonstrated that the new algorithm enhanced the RMS (root mean square error) frequency-offset estimate by 36.2% and the Bit to Error Rate performance by 29.5%

Intelligent Multisensor Cooperative Localization Under Cooperative Redundancy Validation

Localization plays a key role in Internet of Things. This paper proposes a novel intelligent cooperative multisensor localization method called the edge cloud cooperative localization (ECCL) which has the range and angle observations from the neighbor nodes along with the location observations from an absolute coordinate localization system like global positioning system. The edge cloud structure is proposed which employs several distributed Kalman filters in sensor nodes edge and a centralized cooperative fusion unit in the cloud. For a robust fusion, a cooperative redundancy validation method is proposed to detect the outliers. The proposed ECCL scheme has the advantages of both the distributed and centralized localization, which satisfies the needs of high reliability and high accuracy, especially when sensor nodes have limited computational resources. The simulation and experimental results show that our proposed ECCL algorithm outperforms the other schemes both in outlier detection and localization accuracy

The effectiveness and safety of parathyroid hormone in fracture healing: A meta-analysis

The very large economic and social burdens of fracture-related complications make rapid fracture healing a major public health goal. The role of parathyroid hormone (PTH) in treating osteoporosis is generally accepted, but the effect of PTH on fracture healing is controversial. This meta-analysis was designed to investigate the efficacy and safety of PTH in fracture healing. The EMBASE, PubMed, and Cochrane Library databases were systematically searched from the inception dates to April 26, 2018. The primary randomized clinical trials comparing PTH treatment for fracture healing with placebo or no treatment were identified. We did not gain additional information by contacting the authors of the primary studies. Two reviewers independently extracted the data and evaluated study quality. This meta-analysis was executed to determine the odds ratio, mean difference, standardized mean difference, and 95% confidence intervals with random-effects models. In total, 8 randomized trials including 524 patients met the inclusion criteria. There were significant differences in fracture healing time, pain relief and function improvement. There were no significant differences in the fracture healing rate or adverse events, including light-headedness, hypercalcemia, nausea, sweating and headache, except for slight bruising at the injection site. We determined that the effectiveness and safety of PTH in fracture healing is reasonably well established and credible

Mycoplasma genitalium Lipoproteins Induce Human Monocytic Cell Expression of Proinflammatory Cytokines and Apoptosis by Activating Nuclear Factor κB

This study was designed to investigate the molecular mechanisms responsible for the induction of proinflammatory cytokines gene expression and apoptosis in human monocytic cell line THP-1 stimulated by lipoproteins (LPs) prepared from Mycoplasma genitalium. Cultured cells were stimulated with M. genitalium LP to analyze the production of proinflammatory cytokines and expression of their mRNA by ELISA and RT-PCR, respectively. Cell apoptosis was also detected by Annexin V-FITC-propidium iodide (PI) staining and acridine orange (AO)-ethidium bromide (EB) staining. The DNA-binding activity of nuclear factor-κB (NF-κB) was assessed by electrophoretic mobility shift assay (EMSA). Results showed that LP stimulated THP-1 cells to produce tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 in a dose-dependent manner. The mRNA levels were also upregulated in response to LP stimulation. LPs were also found to increase the DNA-binding activity of NF-κB, a possible mechanism for the induction of cytokine mRNA expression and the cell apoptosis. These effects were abrogated by PDTC, an inhibitor of NF-κB. Our results indicate that M. genitalium-derived LP may be an important etiological factor of certain diseases due to the ability of LP to produce proinflammatory cytokines and induction of apoptosis, which is probably mediated through the activation of NF-κB