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Due to the state trajectory-independent features of invariant extended Kalman filtering, it has attracted widespread attention in the research community for its significantly improved state estimation accuracy and convergence under disturbance. In this article, we formulate the full-state data fusion navigation problem for fixed-wing unmanned aerial vehicle (UAV) within a framework based on error-state right-invariant extended Kalman filtering (ES-RIEKF) on Lie groups. We merge measurements from a multirate onboard sensor network on UAVs to achieve a real-time estimation of pose, air flow angles, and wind speed. Detailed derivations are provided, and the algorithm’s convergence and accuracy improvements over established methods like error-state EKF (ES-EKF) and nonlinear complementary filter (NCF) are demonstrated using real-flight data from UAVs. Additionally, we introduce a semi-aerodynamic model fusion framework that relies solely on ground-measurable parameters. We design and train a long short-term memory (LSTM) network to achieve drift-free prediction of the UAV’s angle of attack (AOA) and side-slip angle (SA) using easily obtainable onboard data like control surface deflections, thereby significantly reducing dependence on global navigation satellite systems (GNSS) or complicated aerodynamic model parameters. Further, we validate the algorithm’s robust advantages under GNSS denied, where flight data show that the maximum positioning error stays within 30 m over a 130-s denial period. To the best of authors’ knowledge, this study is the first to apply ES-RIEKF to full-state navigation applications for fixed-wing UAVs, aiming to provide engineering references for designers. Our implementations using MATLAB/Simulink will be open source.

Space/air communications have been envisioned as an essential part of the next-generation mobile communication networks for providing high-quality global connectivity. However, the inherent broadcasting nature of wireless propagation environment and the broad coverage pose severe threats to the protection of private data. Emerging covert communications provides a promising solution to achieve robust communication security. Aiming at facilitating the practical implementation of covert communications in space/air networks, we present a tutorial overview of its potentials, scenarios, and key technologies. Specifically, first, the commonly used covertness constraint model, covert performance metrics, and potential application scenarios are briefly introduced. Then, several efficient methods that introduce uncertainty into the covert system are thoroughly summarized, followed by several critical enabling technologies, including joint resource allocation and deployment/trajectory design, multi-antenna and beamforming techniques, reconfigurable intelligent surface (RIS), and artificial intelligence algorithms. Finally, we highlight some open issues for future investigation.

This article presents the linear and nonlinear theory of a novel quasi-optical gyrotron traveling wave tube (gyro-TWT) at 0.34 THz. The gyro-TWT uses the HE06 mode of a confocal waveguide as its operating mode. Based on the dispersion equation, the linear analysis of confocal gyro-TWT is investigated. Meanwhile, the self-consistent nonlinear theory is developed to analyze the performances of the three-stage confocal waveguide gyro-TWTs. To improve the efficiency, the special fan-shaped electron beam is employed and the nonlinear simulation results indicate that the efficiency can be increased to 23.2%, which is significantly higher than the traditional magnetron injection gun (MIG).

With the rapid growth of the construction industry, precise and efficient monitoring of building deformation has become a crucial factor in ensuring their secure construction and stable operation. The frequent occurrence of occlusion and diffraction errors in satellite signals caused by high-rise buildings has emerged as a primary challenge that constrains the accuracy of positioning in deformation monitoring by BeiDou Navigation Satellite (BDS). To solve the problems, this study proposes an elevation mask angle modeling method of satellite signal occlusion based on azimuth rounding and applies it to real-time BDS building deformation monitoring and positioning algorithm. The proposed approach involves defining a particular subset of integer azimuth and elevation angles, followed by utilizing the minimum elevation angle from this subset to develop a model for the azimuth-dependent elevation mask angle. We aimed to develop an elevation angle mask model using a conventional approach, and the model can be utilized to focus on non-line-of-sight (NLOS) and multipath signals and attenuate their impact on positioning accuracy by reducing their weight. The experimental results show that the elevation angle mask model can be easily completed by using the observation data of BDS satellites in a single day, and its use can make the number of effective satellites involved in the calculation of real-time deformation monitoring of BDS more accurate and reliable. The root mean square (RMS) of positioning results including float solutions was increased respectively by 91.1%, 93.3%, and 72.7% in the direction of East-North-Up (ENU), and the RMS of results with fixed ambiguity was increased by 6.9%, 10.0%, and 29.5%, respectively. Therefore, it can be concluded that the elevation mask angle modeling algorithm is convenient to realize and can significantly improve the performance of deformation monitoring results by BDS.

An intelligent recognition algorithm was developed to identify fibers in the cross sections of blended yarn containing meta-aramid 1313 (Nomex), poly(phenylene-1,3,4-oxadiazole) (POD), flame resistant viscose, and flame-resistant vinylon. The yarn cross section image was obtained at x400 magnification. Drawing software was used to manually isolate single fiber images for training the back propagation (BP) neural network model in Matlab language image processing software. The GrabCut algorithm was used to de-noise the image and separate the target from the background. Finally, single fiber images and fiber distributions were obtained through the program. The result showed that the BP neural network model with the GrabCut algorithm can identify fiber type in a complex background more easily and more accurately than traditional algorithms.

Objective: This study aims to evaluate the effectiveness of individualized hemodialysis for unconventional hypotension in diabetic nephropathy patients.Methods: A total of 60 patients were selected and randomly divided into study group and control group. The control group used the standard dialysis model, while the study group used the individualized hemodialysis scheme, in which the dialysis was performed using an individualized dialysis machine temperature control, pattern of natrium, and pattern of step ultrafiltration in combination with dialysate-containing glucose.Results: The total occurrence rate of hypotension, dry weight standard-reaching rate, and blood quality during and after dialysis in the study group were superior to those in the control group (P< 0.05). Furthermore, the symptom scores in the study group (dizziness score, chest distress score, sweating score, muscle spasm score, gastrointestinal symptom score, and temporary mind change score) were lower than those in the control group (P< 0.05). The serum sodium, potassium, and chloride concentration in these two groups after dialysis was not statistically different (P> 0.05).Conclusion: The combined application of low temperature, pattern of natrium, pattern of step ultrafiltration, and dialysate-containing glucose individualization is safe and effective for preventing and controlling the occurrence of intradialytic hypotension (IDH), improve symptoms, and improve the dry weight standard-reaching rate.

The rapid evolution of an X-linked microRNA (miRNA) cluster in major primate lineages, including human, ape and New World monkey are studied, emphasizing on the tandem duplications and nucleotide substitutions involved. The analysis clearly indicates that the functional novelties caused during evolution are all a result of the rapid adaptive changes associated with the like protein-coding genes.

Purpose: The purpose of this paper is to investigate the internal control disclosure (ICDISC) practices in South Asia and compare those disclosure practices across enforced setting (India) versus comply or explain setting (Pakistan and Bangladesh). Further, whether the audit firm size moderates the relationship between ICDISC practices and board & audit committee effectiveness. Design/methodology/approach: To achieve these objectives, a sample of 100 non-financial companies was selected from Pakistan and India for three years’ period (2013-2015), whereas 93 companies were selected from Bangladesh based on market capitalization. The ICDISC index has been used which is based on the COSO framework. Findings: Results of univariate analysis show that public sector companies in South Asia tend to disclose significantly more internal control information as compared to private sector companies. In terms of enforcement variable, the results of Mann–Whitney test show that companies listed in enforced setting have disclosed significantly greater extent of overall as well as individual categories of ICDISC as compared to companies listed in comply or explain setting. Based on multivariate analysis results for overall sample, it was found that board and audit committee characteristics and ownership by government have positive significant effect on ICDISC except representation of female or foreigner on audit committee which was found negatively significant. In addition to this, listing on foreign stock exchange and enforcement effect emerged as significant variables to influence ICDISC. Finally, the results of additional analysis state that the role of board and audit committee for influencing ICDISC has been moderated by the external auditor size in South Asia. In addition, enforcement variable is highly positively significant for companies having non-big four audit firm. Research limitations/implications: These results imply that enforcement variable acts as an important alternative external control mechanism when companies do not have big four audit firm as their external auditors. Originality/value: This is very first study on ICDISC in South Asia which explores the effect of enforcement and governance on ICDISC practices of firms. It also contributes toward the literature that the regulation on reporting of internal control can be effective in developing country only if there is strong penalty for non-compliance by regulatory authorities.

To evaluate vitality principle in breast cancer rats by pharmacologically developing a model for anticancer surveillance.

A new method for synthetic aperture radar (SAR) target recognition is proposed. This method is accomplished via the combination of active contour without edges, Hu Invariant moments and support vector machine (SVM) classifier. Image segmentation is performed by using active contour without edges. Then seven Hu moments are extracted and normalized as feature vectors. Finally, the SVM classifier is employed for data training and testing by means of MSTAR SAR images. To verify the performance of the proposed method, the traditional active contour (snakes) is used for comparison. The simulation results confirm the feasibility and accuracy of the proposed method in SAR target recognition. [ABSTRACT FROM AUTHOR]

The transfer line balancing problem (TLBP) and the buffer allocation problem (BAP) are amongst the most studied problems on transfer line system. However, the two problems are usually solved separately, although they are closely interrelated. Traditional optimization of TLBP probably leads to a deviation of production rate from the actual performance which is used as the optimization objective of the following BAP, especially when the equipment reliability differences are relatively large. In this paper, an innovative approach, considering machining accessibility and machine reliability, is presented to solve the TLBP and BAP simultaneously. A polychromatic-set-based constraint model and a collaborative optimization algorithm are proposed. A group of Boolean constraint matrixes both for machining feature sets and their optional stations sets are constructed through polychromatic set theory. A new coding mode based on priority, which always keeps all schemes feasible in each iteration and suitable for GA, PSO and other intelligent algorithms, is presented to describe all the allocation information for station, process, buffer and configuration. Optimization objectives including production rate and production cost are evaluated through the COM interface with simulation software. Comparison experiments and a real case of a diesel engine block demonstrate both the validity and efficiency.

In this report, a new type of double-drive photoelastic modulation effect is studied. Two piezoelectric actuators are connected to a symmetric photoelastic crystal at an angle of 45°. The actuators and crystal have the same resonant frequency. By adjusting the amplitude and phase difference between the driving voltages of the two piezoelectric actuators, two special forms of photoelastic modulation can be realized, namely, a pure standing wave form and a pure traveling wave form. The retardation magnitude and the azimuth angle of the modulation fast axis can be regulated in the pure standing wave, and the modulation axis moves circumferentially in the pure traveling wave. We have experimentally observed the two special photoelastic modulation modes, and the test and calibration methods are also reported.

The rapid development of location-based service (LBS) drives one special kind of LBS, in which the service provider verifies user location before providing services. In distributed location proof generating schemes, preventing users from colluding with each other to create fake location proofs and protecting user's location privacy at the same time, are the main technical challenges to bring this kind of LBS into practical. Existing solutions tackle these challenges with low collusion-detecting efficiency and defected collusion-detecting method. We proposed two novel location proof generating schemes, which inversely utilized a secure secret-sharing scheme and a pseudonym scheme to settle these shortcomings. Our proposed solution resists and detects user collusion attacks in a more efficient and correct way. Meanwhile, we achieve a higher level of location privacy than that of previous work. The correctness and efficiency of our proposed solution is testified by intensive security analysis, performance analysis, as well as experiments and simulation results.

Scion wood of 'Caddo' and 'Desirable' pecan (Carya illinoinensis) was grafted onto the epicotyl of 1-month-old, open-pollinated 'Shaoxing' pecan seedlings for evaluation as a grafting technique to reduce the time to produce grafted trees. The results showed that seedlings grafted with "base scions" had higher survival than those grafted with "terminal scions" for both 'Caddo' and 'Desirable'. Also, grafting with paraffinic tape could achieve greater success rate than that with medical tape. The most ideal time to perform this grafting was late April in Nanjing, China, when pecan seedlings were about 35 days old. This study demonstrated that the technique yielded successful epicotyl grafting of >70%, and it could thus be applied in practice. [ABSTRACT FROM AUTHOR]

This study examined the ability to vegetatively propagate 1-year-old pecan (Carya illinoinensis) through the rooting of hardwood cuttings. Cuttings were treated with varying concentrations of different auxins and different combinations of media and ambient temperatures. Under different temperature conditions, all auxin treatments induced the rooting of cuttings but did not promote sprouting. The effectiveness of the induction of adventitious roots was as follows: 1-naphthalene acetic acid (NAA) > indole 3-butyric acid > indole 3-acetic acid. The base of the parent shoot treated by NAA at a concentration of 0.09%, planted in substrate with bottom heat was the most effective, with 82% rooting, 8.3 roots/cutting and root lengths of 7.3 cm. These findings suggested that auxin and substrate/air temperature differences are both indispensable in the process of adventitious roots formation in pecan. This study revealed that the propagation of hardwood cuttings derived from branches of 1-year-old pecan is possible. [ABSTRACT FROM AUTHOR]

The outage probability of a composite microscopic and macroscopic diversity system is evaluated over correlated shadowed fading channels. The correlations on both a microlevel and macrolevel are taken into account for the evaluations. The expression of the desired outage probability is explicitly presented, and two evaluation approaches, i.e. a compact Gaussian-Hermite quadrature method and an effective iterative algorithm, are proposed. The accuracy and efficiency of the proposed approaches are analysed, and a guideline is provided for their application. By employing the proposed evaluation approaches, results and demonstrations are presented, which display the implied effects of the corresponding parameters on the system outage performance, and reveal the potential to facilitate the design and analysis of such composite diversity systems.

Clematichinenoside is a triterpenoid saponin isolated from the roots of Clematis chinensis. Oxidative stress and excessive nitric oxide production are thought to play considerable roles in ischemia/reperfusion injury that impairs cardiac function. The present study investigated the protective effect of clematichinenoside on regional and global ischemia/reperfusion injury and ventricular myocytes. In vivo, regional myocardial ischemia/reperfusion injury of rats was induced by the occlusion of the left anterior descending coronary artery, and isolated guinea pigs heart using Langendorff apparatus served as a global ischemia/reperfusion injury model ex vivo. Primary cultured neonatal ventricular myocytes were further applied to explore the anti-ischemia/reperfusion injury property in vitro. Infarct size was measured with TTC stain; enzyme activities such as lactate dehydrogenase, creatine kinase, superoxide dismutase, malondialdehyde, and nitric oxide were analyzed with assay kits; inducible nitric oxide synthase and endothelial nitric oxide synthase expressions were determined by Western blot. Clematichinenoside attenuated infarct size, decreased lactate dehydrogenase, creatine kinase, and malondialdehyde levels and enhanced superoxide dismutase activity. Clematichinenoside improved hemodynamics indexes, such as left ventricular developed pressure, maximum left ventricular developed pressure, and increase/decrease rate (± dp/dtmax) in the isolated guinea pig heart after reperfusion. Clematichinenoside also inhibited excessive production of nitric oxide through downregulating inducible nitric oxide synthase as well as upregulating endothelial nitric oxide synthase during ischemia/reperfusion injury. Clematichinenoside attenuates ischemia/reperfusion injury in vivo, ex vivo, and in vitro via an antioxidant effect and by restoring the balance between inducible nitric oxide synthase and endothelial nitric oxide synthase. [ABSTRACT FROM AUTHOR]

The April 20, 2013, Ms7. 0 Lushan earthquake was successfully recorded by closely spaced Continuous Global Positioning System (CGPS) stations owned by the Crustal Movement Observation Network of China (CMONC). The 1-Hz GNSS data from eight CGPS stations, which are located between 30km and 200km from the hypocenter, were processed within quasi-real-time. The near-field surface deformation indicated the following characteristics: the near-field movements were limited to several centimeters; the peak of the deformation wave was significantly larger than the static permanent offset; at the beginning of the event, the north wall of the fault moved to the southeast as the south wall moved to the southwest; station SCTQ, which was the closest station to the hypocenter at 30km, had the largest static permanent displacement of 2cm; the peaks of the deformation waves were 1. 5cm, 5cm and 3cm, to the east, the south and vertically upward, respectively ; and the peaks of velocity and acceleration, derived from the deformation, were 3. 4cm/s and 5. 3cm/s2, respectively.

The training of distribution operators is an important link to ensure the safe operation to effectively enhance the training effect,the paper put forward a new teaching form that combining the line operation and simulation training. It firstly analyzes the distribution network simulation training function demand, then designs training simulation system structure,extracts simulation training process,introduces the key technology:three-dimensional simulation technology,then simulation training process,finally gives the system development example. The application result shows the power line operation simulation training system can effectively guarantee the operation training effect,has a great practical significance.

AbstractThe paper demonstrates the flow behavior in a high specific speed axial-flow pump at part-load condition by numerical methods. The unsteady Reynolds averaged NavierStokes equations (URANS) with the filter-based model were solved by using the computational fluid dynamics code ANSYS CFX and the hydraulic performance of axial-flow pump was estimated. At part-load condition numerical results show that parameters of hydraulic performance predicted by the filter-based model are proved to match with the experiment results better than that of the standard k-εmodel. Furthermore, we analyzed the internal flow field within the axial-flow pump in fully developed stall and in deep stall, respectively, and compared the obtained typical flow features with the flow visualization experimental results in (I. Goltz, 2003). The boundary vorticity flux (BVF) was introduced to diagnose the internal flow field inside blade passage at part-load condition and to find out the root of the instability vortices. Based on the BVF diagnosis, the differences about the numerical results of flow fields in deep stall were further analyzed between the standard k-εmodel and the filter-based model. It show that the filter-based model is more practical to capture the unsteady flow structures than the standard k-εmodel.

This article analyzes the causes of "longevity building" and "ephemeral building" in architectural design practice. From the perspective of system theory proposed that the essence of architectural design is dynamic and dynamic process. Static factors only as a carrier of the existence of dynamic factors, establish framework for wisdom architectural design, provide new approach for architectural design.

Three new limonoids (toonaciliatins N-P, 1-3) and four new pimaradiene-type diterpenoids (toonacilidins A-D, 4-7) were isolated from the leaves and twigs of Toona ciliata Roem. var. yunnanensis. Their structures were elucidated on the basis of spectroscopic methods. Toonacilidin B (5) showed moderate inhibitory activity against H. pylori-SS1 with an MIC of 50 μg/mL. [ABSTRACT FROM AUTHOR]

Experimental research was conducted on the transverse stress of 32m post-tensioned precast simply supported concrete box girder with ballastless track. Vibrating wire strain gauges were embedded in the key sections to monitor the concrete transverse strain. The concrete strain development law was analyzed. The monitored results showed that there were low transverse tensile stresses and the cracking resistance of the girder was enough during pre-tensioning stage. The research findings provided effective experimental data for design and construction quality control.

The research on data streams clustering has become a focus in the field of data streams mining. Because the number of data streams is too large, and CPU of the computer has limited memory and time, it’s difficult to carry out clustering quickly and effectively. For that problem, we design an improved clustering algorithm for dynamic data streams based on principal component analysis and density. The PDStream algorithm effectively overcomes the shortcomings of the STREAM algorithm controlled by historical data and the CluStream algorithm is difficult to describe non-spherical and out "old data", resulting in huge amount of data. In the course of the experiment, we compare with the STREAM algorithm, the PDStream algorithm shows the superiority of handling mass data and the characteristics of high-quality clustering.

C22H32N4O13S2Zn, triclinic, P1̅ (no. 2), a= 9.496(1) Å, b= 10.016(1) Å, c= 16.334(2) Å, α= 102.297(10)°, β= 93.625(10)°, γ= 111.313(10)°, V= 1397.1 Å3, Z= 2, Rgt(F)= 0.0383, wRref(F2)= 0.1020, T= 296 K.

We present the first lattice-QCD calculation of the unpolarized strange and charm parton distribution functions using large-momentum effective theory. We use a lattice ensemble with (2+1+1) flavors of highly improved staggered quarks generated by the MILC Collaboration, with lattice spacing a≈0.12 fm and Mπ≈310 MeV, and clover valence fermions with two valence pion masses: 310 and 690 MeV. We use momentum-smeared sources to improve the signal up to nucleon boost momentum Pz=2.15 GeV, and determine nonperturbative renormalization factors in regularization independent momentum subtraction scheme. We compare our lattice results with the matrix elements obtained from matching the parton distribution functions (PDFs) from CT18NNLO and NNPDF3.1NNLO global fits. Our data support the assumptions of strange-antistrange and charm-anticharm symmetry that are commonly used in global PDF fits. [ABSTRACT FROM AUTHOR]

A new coupling method is proposed for high-power laser-diode-array (LDA) end-pumped large-aperture amplifiers. In this method, stacks in the LDA are distributed on a spherical surface, and a hollow duct is placed after them. Both numerical simulations and experimental research have been done for this method. All results show that high coupling efficiency and uniform pumping field can be obtained simultaneously using this method.

In this article, a new copolymer of L‐aspartic acid and L‐glutamic acid, which may be a biodegradable high molecular polymer and can be used more widely in many areas, was synthesized. The conditions of preparation, such as catalyst, reaction time, reaction temperature, the amount of catalyst, the times of adding catalyst, and the molar ratio of L‐aspartic acid to L‐glutamic acid, were optimized. The copolymer was characterized by 13C NMR, infrared spectroscopy, and X‐ray diffractometer. The molecular weight was determined by GPC. The result indicated that production yield, purity of product, and molecular weight of product increased with amount of catalyst and molar ratio of L‐aspartic acid to L‐glutamic acid increasing. The best condition of preparation was the following: reacting 2–4 h at the temperature of 180–200°C. The product yield with the molecular weight 13,000.00 reached 63.2% and the purity of product was 96.33% when the copolymerization was carried out at the temperature of 200°C under vacuum for 2 h. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3626–3633, 2006

The atmospheric pressure surface barrier discharge (APSBD) in air has been used in killing Escherichia coli (E. coli). There is almost no bacterial colony in the sample after treatment by discharge plasma for 2 min. A diagnostic technique based on mass spectrum has been applied to the discharge gas and the mechanism of killing is discussed. Ozone and monatomic oxide are considered to be the major antimicrobial active species. There is almost no harmful by-product. The experiment proves that APSBD plasma is a very simple, effective and innocuous tool for sterilization.

A layered superlattice PMo123-DODA+self-assembled composite film has been successfully prepared. Infrared (IR) spectra revealed that the Keggin structure characteristic of the PMo12O403-anion was preserved in the composite film. A well-ordered superlattice structure, d spacing of 2.945 nm, was identified by X-ray diffraction (XRD). The superlattice film showed good photochromic properties. On irradiation with UV light, the transparent film changed from light yellow to blue. Then, bleaching occurred when the film was in contact with ambient air or O2in the dark. The photochromic mechanism was studied by electron spin resonance (ESR), IR spectra, and UV-Vis spectra.

In 1984, 40 mature and 100 immature signal crayfish, Pacifastacus leniusculus(Dana), were introduced into the River Great Ouse, England. By 1994, the population had spread up and down stream to occupy an 11.4 km river section. The estimated density and biomass (wet weight) of the population in 1993 were highest in summer at 4.0 m−2and 133 g m−2respectively, with annual means of 2.2 m−2and 82 g m−2for crayfish of >30 mm carapace length (CL) in the pool (P2) where the crayfish were originally introduced. Density and biomass were 15 m−2and 78 g m−2, with annual means of 6.1 m−2and 33 g m−2for crayfish of all sizes in a riffle 300 m downstream from P2. An annual survival rate of 14% was estimated for crayfish >30 mm CL in P2 in 1993. The relative abundance estimated for six riffles and six pools in 1994 showed that crayfish abundance decreased gradually from the original site of introduction both up and down the river. Estimated annual production of crayfish >35 mm CL in P2 for 1993 was 52.58 g m−2WW, with a turnover ratio (production/biomass) of 0.44.

In recent years, the number of young teachers in the colleges and universities at the capital (Beijing) has rapidly increased. Today, the number of young faculty members under the age of thirty-five has already reached approximately one-third of the total number of teachers. These teachers make up the future, and the hope, of our country's higher education. Their political and professional quality will to a certain degree determine the quality and standards of China's higher education for the next ten to twenty years. The "fault" in the ranks of teachers and professors created by the ten years of chaos and turmoil, and the invasion of the wave of bourgeois liberalization, have made the task of grasping the construction of the ranks of young teachers and professors a major lesson that requires urgent attention and resolution.