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Real-time localization is an important mission for self-driving cars and it is difficult to achieve precise pose information in dynamic environments. In this paper, a novel localization method is proposed to estimate the pose of self-driving cars using a 3D-LiDAR sensor. First, the multi-frame curb features and laser intensity features are extracted. Meanwhile, based on the high-precision curb map generated offline, obstacles on road are detected using region segmentation methods and their features are removed. Furthermore, a map-matching method is proposed to match the features to the map, a robust iterative closest point algorithm is utilized to deal with curb features along with a probability search method dealing with intensity features. Finally, two separate Kalman filters are used to fuse the low-cost global positioning systems and map-matching results. Both offline and online experiments are carried out in dynamic environments and the results demonstrate the accuracy and robustness of the proposed method.
We study the pricing of timer options in a class of stochastic volatility models, where the volatility is driven by two diffusions—one fast mean-reverting and the other slowly varying. Employing singular and regular perturbation techniques, full second-order asymptotics of the option price are established. In addition, we investigate an implied volatility in terms of effective maturity for the timer options, and derive its second-order expansion based on our pricing asymptotics. A numerical experiment shows that the price approximation formula has a high level of accuracy, and the implied volatility in terms of its effective maturity is illustrated.
The potential relationship between service demands and remanufacturing services (RMS) is essential to make the decision of a RMS plan accurately and improve the efficiency and benefit. In the traditional association rule mining methods, a large number of candidate sets affect the mining efficiency, and the results are not easy for customers to understand. Therefore, a mining method based on binary particle swarm optimization ant colony algorithm to discover service demands and remanufacture services association rules is proposed. This method preprocesses the RMS records, converts them into a binary matrix, and uses the improved ant colony algorithm to mine the maximum frequent itemset. Because the particle swarm algorithm determines the initial pheromone concentration of the ant colony, it avoids the blindness of the ant colony, effectively enhances the searchability of the algorithm, and makes association rule mining faster and more accurate. Finally, a set of historical RMS record data of straightening machine is used to test the validity and feasibility of this method by extracting valid association rules to guide the design of RMS scheme for straightening machine parts.
Jurassic sandstones in the Xiongcun porphyry copper–gold district, southern Lhasa subterrane, Tibet, China were analysed for petrography, major oxides and trace elements, as well as detrital zircon U–Pb and Hf isotopes, to infer their depositional age, provenance, intensity of source-rock palaeo-weathering and depositional tectonic setting. This new information provides important evidence to constrain the tectonic evolution of the southern Lhasa subterrane during the Late Triassic – Jurassic period. The sandstones are exposed in the lower and upper sections of the Xiongcun Formation. Their average modal abundance (Q21F11L68) classifies them as lithic arenite, which is also supported by geochemical studies. The high chemical index of alteration values (77.19–85.36, mean 79.96) and chemical index of weathering values (86.19–95.59, mean 89.98) of the sandstones imply moderate to intensive weathering of the source rock. Discrimination diagrams based on modal abundance, geochemistry and certain elemental ratios indicate that felsic and intermediate igneous rocks constitute the source rocks, probably with a magmatic arc provenance. The detrital zircon ages (161–243 Ma) and εHf(t) values (+10.5 to +16.2) further constrain the sandstone provenance as subduction-related Triassic–Jurassic felsic and intermediate igneous rocks from the southern Lhasa subterrane. A tectonic discrimination method based on geochemical data of the sandstones, as well as detrital zircon ages from sandstones, reveals that the sandstones were most likely deposited in an oceanic island-arc setting. These results support the hypothesis that the tectonic background of the southern Lhasa subterrane was an oceanic island-arc setting, rather than a continental island-arc setting, during the Late Triassic – Jurassic period.
The reconstruction of Holocene environmental changes in lakes on the plateau region of southwest China provides an understanding of how these ecosystems may respond to climate change. Fossil diatom assemblages were investigated from an 11,000-year lake sediment core from a deep, alpine lake (Lugu Hu) in southwest China, an area strongly influenced by the southwest (or the Indian) summer monsoon. Changes in diatom assemblage composition, notably the abundance of the two dominant planktonic species, Cyclotella rhomboideo-elliptica and Cyclostephanos dubius, reflect the effects of climate variability on nutrient dynamics, mediated via thermal stratification (internal nutrient cycling) and catchment-vegetation processes. Statistical analyses of the climateediatom interactions highlight the strong effect of changing orbitally-induced solar radiation during the Holocene, presumably via its effect on the lake’s thermal budget. In a partial redundancy analysis, climate (solar insolation) and proxies reflecting catchment process (pollen percentages, C/N ratio) were the most important drivers of diatom ecological change, showing the strong effects of climateecatchmentevegetation interactions on lake functioning. This diatom record reflects long-term ontogeny of the lake-catchment ecosystem and suggests that climatic changes (both temperature and precipitation) impact lake ecology indirectly through shifts in thermal stratification and catchment nutrient exports.
Animal studies have suggested that Mn might be associated with some components of the metabolic syndrome (MetS). A few epidemiological studies have assessed dietary Mn intake and its association with the risk of the MetS and its components among Chinese adults. In this study, we assessed daily dietary Mn intake and its relationship with MetS risk among Chinese adults in Zhejiang Province using data from the 5th Chinese National Nutrition and Health Survey (2010–2012). A total of 2111 adults were included. Dietary Mn intake was assessed using 3-d 24-h dietary recalls; health-related data were obtained by questionnaire surveys, physical examinations and laboratory assessments. The mean intake of Mn was 6·07 (sd 2·94) mg/d for men (n 998) and 5·13 (sd 2·65) mg/d for women (n 1113). Rice (>42 %) was the main food source of Mn. The prevalence of the MetS was 28·0 % (590/2111). Higher Mn intake was associated with a decreased risk of the MetS in men (Q4 v. Q1 OR 0·62; 95 % CI 0·42, 0·92; Ptrend=0·043) but an increased risk in women (Q4 v. Q1 OR 1·56; 95 % CI 1·02, 2·45; Ptrend=0·078). In addition, Mn intake was inversely associated with abdominal obesity (Ptrend=0·016) and hypertriacylglycerolaemia (Ptrend=0·029) in men, but positively associated with low HDL-cholesterol in both men (Ptrend=0·003) and women (Ptrend<0·001). Our results suggest that higher Mn intakes may be protective against the MetS in men. The inverse association between Mn intake and the MetS in women might be due to the increased risk for low HDL-cholesterol.
A mass-conserving lattice Boltzmann model based on the Bhatnagar-Gross-Krook (BGK) model is proposed for non-Newtonian fluid flows. The equilibrium distribution function includes the local shear rate related with the viscosity and a variable parameter changing with the shear rate. With the additional parameter, the relaxation time in the collision can be fixed invariable to the viscosity. Through the Chapman-Enskog analysis, the macroscopic equations can be recovered from the present mass-conserving model. Two flow problems are simulated to validate the present model with a local computing scheme for the shear rate, and good agreement with analytical solutions and/or other published results are obtained. The results also indicate that the present modified model is more applicable to practical non-Newtonian fluid flows owing to its better accuracy and more robustness than previous methods.
Blue and Green long-persistent luminescence materials have been fully developed, and are well featured in production and application. However, long-wavelength emitting materials are very rare relatively. This paper presents some work from our laboratory on the recent progress in long-wavelength emitting long-persistent luminescence materials: Sr3Al2O5Cl2: Eu2+, Tm3+, Sr2SnO4: Sm3+ and Ca2BO3Cl: Eu2+, Dy3+. The initial intensity of Sr3Al2O5Cl2: Eu2+, Tm3+ can reach nearly 5000 mcd/m2 and its afterglow can last about 220 min at recognizable intensity level. Sr2SnO4: Sm3+ has a red emission and its afterglow time of which sintered in vacuum atmosphere increased substantially. With optimum doping concentration and sufficient excitation with UV light, the yellow afterglow of Ca2BO3Cl: Eu2+, Dy3+ can persist over 48 h.
The anti-inflammatory effects of two esters of α-tocopherol (α-TOH), all-rac-α-TOH acetate (dl-α-TOA) and RRR-α-TOH succinate (d-α-TOS), on broilers repeatedly challenged with lipopolysaccharide (LPS) were investigated. Three hundred and twenty 1-d-old broiler chicks were allotted into four treatment groups and fed on a control diet (30 mg/kg dl-α-TOA) or diets containing 10, 30, 50 mg/kg d-α-TOS. Half of the birds from each treatment group were challenged with 0·9 % NaCl solution or LPS (250 μg/kg body weight) at 16, 18 and 20 d of age. The results indicated that the pretreatment of birds with 50 mg/kg d-α-TOS markedly reduced serum PGE2 secretion and increased the concentrations of serum or hepatic α-TOH. When LPS-challenged birds were pretreated with 30 or 50 mg/kg d-α-TOS, the increases of plasma and splenic concentrations of interferon-γ, IL-1β, IL-2, IL-6, IL-4 and IL-10 were dramatically attenuated. Also, a significant decrease of hepatic reactive oxygen species (ROS) and hepatic or splenic phosphokinase C (PKC) activities was found in birds pretreated with 30 or 50 mg/kg d-α-TOS. Furthermore, d-α-TOS inhibited the activation of NF-κB by preventing the degradation of inhibitory-κBα. In conclusion, D-α-TOS is able to prevent LPS-induced inflammation response in vivo. The beneficial effect may depend on suppressing the secretion of various plasma and splenic inflammatory mediators through inhibiting NF-κB activation and by blocking ROS signalling, in which PKC may play an assistant role.
In this work, formation of diamond coating is studied using large-scale molecular dynamics (MD) simulation. The diamond coating is studied to explore how and to what extent the temperature and pressure affects the deposition structure. To analyze the coating results, the radial distribution function and the fraction of diamond (sp3 bonds) is calculated. It is found that the sp3 fraction in the deposition structure increases with the temperature and pressure. When the pressure becomes large enough (10 GPa), the effect of the pressure on the coating structure is quite small and the sp3 fraction tends to be constant.
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