最新刊期
卷 51 ， 期 1 ， 2012
- 摘要：The optimal reinsurance-investment strategy for an insurer with an exogenous liability is considered. Assume that the aim of the insurer is to maximize the expected exponential utility of the terminal wealth; the surplus process of the insurer follows a diffusion model while the risky assets' prices and the exogenous liability are governed by geometric Brownian motions. By employing the stochastic dynamic programming, the closed form of the optimal reinsuranceinvestment strategy and the optimal value function are derived under two cases: (i) the insurer can invest in a financial market and purchase proportional reinsurance or acquire new business, (ii) the insurer can invest in a financial market and purchase proportional reinsurance, but not acquire new business. Finally, a numerical example is given to show the impact of the exogenous liability and the market parameters on the optimal strategy.关键词：portfolio;reinsurance;asset-liability management;utility maximization;exogenous liability
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发布时间：2023-12-11 - 摘要：Image inpainting is the process of filling in missing parts of damaged images based on information gleaned from surrounding areas. A new algorithm for inpainting based on the NavierStokes equation, which allows for inpainting inside of the inpainting region and denoising outside of the inpainting region, is outlined. The experimental results show the effective performance of the proposed model in restoring scratched photos, missing parts and even removal of entire objects from images.关键词：inpainting;denoising;NavierStokes equation;isophote direction
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发布时间：2023-12-11 - 摘要：The existence of positive solutions is discussed for a prey-predator model with cross-diffusion. The prior estimate to the positive solutions of the model is given by means of maximum principle and Harnack inequality. By using the integral property, the nonexistence of the nonconstant positive solutions is proved. The sufficient conditions for the existence of nonconstant positive solutions are obtained.关键词：cross-diffusion;nonconstant positive solution;degree theory
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发布时间：2023-12-11 - 摘要：The general method of constructing high-resolution schemes to solve 2D shallow water equations is studied. Using the technique of group velocity control, some high-resolution schemes are obtained, such as three-order upwind group velocity control schemes and four-order group velocity control schemes. Using the dispersion and anisotropy measurement, a criterion to evaluate approximation degree of difference operators to differential operators is obtained.关键词：high-resolution schemes;group velocity control;2D shallow water equations
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发布时间：2023-12-11 - 摘要：In order to develop and improve the theory about existence of positive solutions of fourth order boundary value problem,the following fourth order boundary value problem {u(4)关键词：fourth order boundary value problem;the existence of positive solutions;fixed point theorem;cone
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发布时间：2023-12-11 - 摘要：The oscillation for a class of higher order nonlinear variable delay functional differential equation with positive and negative coefficients and damping term is discussed. By introducing parameter function and the generalized Riccati transformation, some criteria for the oscillation of the equation are proposed. These criteria improve the restriction of the conditions for the equation. And these results improve and generalize some corresponding known results. Some examples are given to illustrate the main results.关键词：positive and negative coefficient;functional differential equation;variable delay;damping term;Riccati transformation;oscillation
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发布时间：2023-12-11 - 摘要：An easy method on fuzzy interpolative control is introduced to solve the problem of truck backerupper. Without the effect of optimal control rules, a simple and efficient automatic truck backerupper is achieved. The simulations show that the control performance has many advantages, such as rapid response and high control precision. The method is strongly universal. Under the same conditions,it is significantly better than conventional fuzzy control.关键词：interpolative;fuzzy control;truck backerupper;simulation
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发布时间：2023-12-11 - 摘要：Using the urban environment noise emission and propagation model,also considering the attenuation impact of buildings and tree belts on noise , an urban environment noise simulation and evaluation system named “Zhong Da Sheng Tu” was developed with the help of geographical information system(GIS). The noise emission，propagation model of point, line and plane source were set up in the system. As for the traffic noise of line source, GIS was used to obtain the information of roads and buildings. The road traffic noise distribution of urban area was calculated with the vehicle noise emission model. The calculation results were imported to GIS to make the traffic noise map. At last, the system was used to simulate the urban traffic noise and evaluate the effect of noise reduction measures, results show that the systems algorithm is accurate and efficient.关键词：road traffic noise;simulation and evaluation system;geographical information system;noise map
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发布时间：2023-12-11 - 摘要：With higher packages loss ratio channel and noise channel, improving image performance of video multicast transmission is an importance problem for communication technology. Based on compressed sensing,a decoding method of recover image was achieved as videos are suitable for multicast transmission channel. By investigating the best configuration of measurements matrix and sparse bases as well as video interframe correlation,the reweight l1-minimization decoding of video intra-frame and interframe decoding with motion estimation were realized. At random Gaussian noise and loss ratio channel model, comparing the method with Softcast, experiment results show that the method is effective.关键词：video multicast;compressed sensing;matrx;decoding
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发布时间：2023-12-11 - 摘要：Population isolation, arithmetic crossover and optimum reserved strategy are used to improve micro-genetic algorithm (mGA). Reset frequency is decreased while the global and local searching capabilities of mGA between two resets are enhanced, which makes mGA searching the parameter space intelligently as the mode recognition information is preserved as much as possible. Realcode is used to decrease the computing cost in encoding and decoding. Adaptive random mutation with existing genetic information of the current groups is used to increase efficient search. Heterogeneous strategy is used to improve the probability of convergence to global optimal solution and quicken up the convergence. Finally, standard functions testing demonstrate that the improved mGA can find better optimum solutions with less computing cost than standard genetic algorithm (SGA).关键词：micro genetic algorithm;heterogeneous strategy;adaptive random mutation;arithmetic cross;real code
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发布时间：2023-12-11 - 摘要：The software for simulating field electron emission from one dimensional nano materials, including its physical background, the algorithm and a demonstration,was developed.The field emission from individual boron nanowire was calculated and the result is consistent with experimental result reported by other group.关键词：nano material;field emission;simulation
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发布时间：2023-12-11 - 摘要：A method of gas chromatographymass (GC-MS) spectrometry was developed for the quantitative analysis of gasoline trace in fire debris. Eight compounds, such as aromatic hydrocarbons, nalkane and naphthalene, were selected as target compounds for quantitative analysis. The results showed that the linear range of eight compounds was 0.1～50 μg/mL with correlation coefficients r2more than 0.995．The relative standard deviation (n=7) was less than 5%. Fire debris analysis indicated toluene showed the highest content in fresh gasoline. Three compounds were detected in carpet residues after burning, while eight compounds were detected in cement bricks.关键词：GC-MS;gasoline;fire debris;quantitative analysis
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发布时间：2023-12-11 - 摘要：To remove copper (Ⅱ) from wastewater, the biosorption of copper (Ⅱ) by the mangrove endophytic fungusFusarium sp#ZZF51 from the South China Sea was studied in this work. The biosorption equilibrium time of copper (Ⅱ) ions onto the tested fungus powders was determined to be 90 min. The optimized condition was pH 6.5, copper (Ⅱ) initial concentration 50 mg/L, adsorption time 90 min with 82.14% of removal efficiency, and 20.53 mg/g of biosorption capacity. The experimental data were analyzed by using the Langmuir model and the Freundlich model. The result indicated that the Langmuir isotherm model provided better correlation with the experimental data. The FTIR analysis confirmed that hydroxyl and carboxyl groups both gave an important contribution to the copper (Ⅱ) adsorption process.关键词：mangrove endophytic fungus;Fusarium sp#ZZF51;biosorption;copper (Ⅱ)
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发布时间：2023-12-11 - 摘要：To control the quality of electrolyzed oxidizing water (EOW), the effects of electrolyte concentration (c(NaCl)), voltage (U) and electrolytic time (t) on available chlorine concentration (ACC) of electrolyzed oxidizing water were investigated. The results showed that when c(NaCl),U and t were in the range of 5.0~9.0 g·L-13.0V~8.0 V and 2.0~6.0 s, respectively, ACC had linear correlation with c(NaCl) and t, and exponential correlation with U. The mathematic model was built up by these relations. It was ACC = 2.753e0.1888Uc(NaCl)t- 36.82te-0.2152U- 37.23 c(NaCl)e-0.5124U+ 87.24e-0.05856U(R2=0.9945,α<0.001). This mathematic model could estimate the ACC with average relative error of 2.45%. It was useful for EOW automatic control system and the control of water quality.关键词：electrolyzed oxidizing water;preparation parameters;available chlorine concentration;mathematic model
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发布时间：2023-12-11 - 摘要：A novel ruthenium(Ⅱ) polypyridyl complex ［Ru(dip)2(DBHIP)］(ClO4)2(dip = 4, 7- diphenyl-1,10-phenanthroline, DBHIP = 2-(3,5-dibromo-4-hydroxyphenyl)imidazo ［4,5-f］［1,10］phenanthroline) was synthesized and characterized. The DNAbinding property of the complex was investigated by spectroscopic methods and viscosity measurement. The results indicated that the complex interacted with DNA through intercalative mode. The photocleavage of pBR322 DNA by Ru(Ⅱ) complex was investigated. The complex induced the aggregation of plasmid pGL3 DNA by Gel retardation assay.The antioxidant activity of the ligand and the complex was also performed.关键词：ruthenium complex;DNA condensation;DNAbinding
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发布时间：2023-12-11 - 摘要：Nocardiosis is a commercially important disease in cultured largemouth bass in China, causing substantial economic losses. However, the pathogen causing largemouth bass nocardiosis has not yet been isolated in China. In this study, a strain ofNocardia(designed as NH090627) was isolated from diseased largemouth bass reared in Nanhai, Guangdong. The bacteria appeared Grampositive, beadlike or long, slender, filamentous rods in shapes. The traditional physiological and biochemical methods showed that most of the phenotypes of strain NH090627 were similar toNocardia. Phylogeny analysis with 16S rDNA showed that the strain NH090627 was branched into the same cluster as that of other species ofNocardia ,and had a higher identity withNocardia seriolaeJCM 3360T(99.9%). Based on morphological, physiological, biochemical properties and phylogenetic analysis, the filamentous rod bacterial was identified asNocardia seriolae.Antimicrobial susceptibility assay showed that this strain was susceptible to chloramphenicol, streptomycin, kanamycin and tetracycline, but high resistant to sulphamethoxazole and ampicillin.关键词：largemouth bass;Nocardia seriolae;physiological and biochemical properties;16S rDNA;drug sensitivity test
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发布时间：2023-12-11 - 摘要：As a member of grouper familyEpinephelus coioidesis one of the most commonly cagecultured species in southern areas of China. Although groupers production are becoming more popular in worldwide markets, the aquaculture industry of this specie is still poorly developed when compared to other marine fish species aquacultured such as stripped bass, cobia, gilthead seabream. Despite of other factors affecting the expansion of cultured area for groupers, the price and steady provision of larvae are important determinants, which depend on effectiveness of the larval culture. Nowadays, grouper larvae for aquaculture in China are mostly from Hainan province due to its favorable conditions for larval culture such as good water quality, suitable temperature. However, mass production of grouper larvae is still encountering many difficulties, and high mortalities were often reported in grouper larvae culture, which affects its industry development. The low survival rate of grouper larvae cultured is due to the poor firstfeeding conditions such as live prey deprivation or environmental stress. The aim of this paper is to compare and discuss effects of various water cultivation regimes on plankton community in grouperEpinephelus coioideslarviculture ponds (2.5 m × 4.0 m ×1.1 m，W×L×H). Four cultivation regimes were designed. In group 1 (G1) and group 2 (G2), two different levels of prepared effective microorganisms solution (EMS) (40 mL·m-3for G1 and 80 mL·m-3 for G2, respectively) and two different levels of shrimp chip (SC) (4 g·m-3 for G1 and 8 g·m-3 for G2, respectively) were daily added one week prior to hatching. Effective Microorganisms comprised ofClostridiums, Photosynthetic bacterium, Lactobacillus, SaccharomycesandNitrobacteriaspecies. In group 3 (G3) and group 4 (G4), only preparedPlatymonusspp. solution (PS) was daily added one day prior to hatching at a level of 2.5 L·m-3 for G3 and a level of 5 L·m-3 for G4, respectively. Each group contained three replicates. Results showed that G1 and G2 had more species of phytoplankton and zooplankton than G3 and G4 did. Both phytoplankton and zooplankton populations density could be significantly improved by EMS and SC additions. G2 had a high density of zooplankton populations (1.3 × 10.5 ~2.1 × 10.5 ind·L-1) during the larval culture period. Zooplankton populations density in G1 and G2 were significantly higher than noted in G3 and G4 during the larval culture period (P≤0.05). In the present studies, high density of zooplankton populations observed in G2 indicates that effective microorganisms do have a positive role in improving zooplankton biomass of grouper experiment ponds. Additionally, a brown water environment came into being in ponds which been added shrimp chip and brown sugar. This may play a role in alleviating possible external stress to grouper larvae. Overall, abundant zooplankton biomass as live prey for grouper larvae growth would be constantly attained by additions of EMS and together with SC.关键词：grouperEpinephelus coioides;plankton community;water cultivation regime;experiment pond
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发布时间：2023-12-11 - 摘要：As the continued excavation for economic benefits of bamboo resources, it has been a problem which is urgent need to solve to know the distribution and dynamic information of bamboo forest timely and accurately. However, the traditional field survey cannot meet this demand. The development of Geomatics technology has provided new approaches to seize the bamboo forest distribution information, but restricted by many factors, the extraction of bamboo information is not effective for quite a long time. On the basis of former studies, the paper took the highresolution of ALOS image as the data source and focuses on bamboo forest information extraction in Shunchang County, which is hilly area in Southern China, with the algorithm of Filmbased & Classoriented which has been put forward by us, in order to test the effectiveness of the method. In addition to using the traditional classification method of pixelbased, it introduced the objectoriented method that has been fashional in recent years, in order to compare them. What's more, it processed the nonfilm area further for higher bamboo forest information extraction accuracies. Verifying with the surveying points showed that the extraction accuracies with pixelbased and objectoriented were 84.42% and 86.46% respectively with Kappa of 0.677 3 and 0.723 4. Four results could be indicated. Firstly, both these two methods showed that the algorithm of Filmbased & Classoriented was well suitable for the bamboo forest information extraction, and could supply a significant technical reference to the image interpretation of hilly area. Secondly, from the accuracy, the method of objectoriented was a little better than the pixelbased one. Nevertheless, from the visual effect of view, there were spiced salt shapes in the figure of pixelbased, while that of objectoriented had better continuity. Although the results of these two methods were little different, the objectoriented one may be more suitable for the highresolution images such as ALOS image. Thirdly, it is hard to interpret and extract the bamboo forest information with the help of spectral features from remote sensed images single, so we have to bring in the texture information to raise the extraction accuracy. In addition to these, the terrain factors including elevation, slope and aspect are needed to regard carefully. We could infer that the bamboo forest information extraction accuracy will be raised more if the terrain combination conditions were taken to account.关键词：film;classoriented;bamboo forest;ALOS image;objectoriented;Shunchang County
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发布时间：2023-12-11 - 摘要：Using St－cindex，MD index，MFD index，FN1index，MAI index，MSHDI index，AR index and RU index，the evaluate model of eco-tourism disturbance was created. with the evaluate model, tourism disturbance of the Wuyishan Natural Heritage vegetation landscape was studied, furthermore, Cluster degree and contribution rate of 8 model indices were analyzed by using MSM-PP for the first time. The result showed that: the Dazulan，the xianfengling，the Guadun and the Shuangxikou scenery spots were disturbed lest seriously; the Taoyuanyu，the Luojiadong，the Shuangquansi，the Masu，the Xianfengling and the Huangganshan scenery spots were disturbed less seriously; the Aotou and the Sangang scenery spots were disturbed most seriously. Evaluate disturbance contribution rate of 8 model indices was list as blow：St－c index=MD index=MFD index> RU index>MSHDI index >FN1index>AR index and> MAI index.关键词：the Wuyishan Natural Heritage;eco-tourism;vegetation landscape;disturbance model;MSM-PP
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发布时间：2023-12-11 - 摘要：Four probability distribution models, generalized extreme value distribution, Weibull distribution, loglogistic distribution and Pearson typeIII distribution, were used to calculate the different return levels of maximum daily precipitation for 85 stations in Guangdong province. The main results are as follows: 1) The results of parameter estimation indicate that there is no universally applicable extreme precipitation probability distribution model; 2) The extreme precipitation occurs more frequently in the Pearl River Delta and the coastal areas of Guangdong among which Qingyuan, Shanwei and Yangjiang are three extreme precipitation centers; 3) The return levels of extreme precipitation differ greatly between the calculations of four probability distribution models.关键词：threeparameter probability distribution models;extreme precipitation;goodnessoffit test;return levels;Guangdong
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发布时间：2023-12-11 - 摘要：The effects of different culture conditions including temperature, pH, initial phenanthrene concentration and cosubstrates on the growth of a phenanthrenedegrading strain PE15011 affiliated to the genus 〖WTBX〗Azospirillum〖WTBZ〗 were studied. The potential degradation of fluoranthene and pyrene by strain PE15011 in liquid culture medium or soil microcosm were investigated. The strain shows better growth under slightly acid culture conditions. Optimal temperature and pH are as 30 °C and 5.0 respectively in a mineral salts liquid medium with phenanthrene at 50 mg/L as the sole substrate. The strain is able to tolerate higher initial phenanthrene concentration than 200 mg/L, while an obvious lag phase is observed when the strain is exposed to high initial phenanthrene concentration. The growth of strain PE15011 is transitorily enhanced by the individual addition of acetic acid, dissolved fulvic acid or dissolved humic acid as the cosubstrate of phenanthrene. Strain PE15011 is able to grow in liquid culture media by utilizing phenanthrene or fluorenthene as the sole carbon and energy source with the potential to degrade fluorenthene but not pyrene. The removal of phenanthrene, fluorenthene or pyrene is enhanced by adding strain PE15011 in sterile soils.关键词：phenanthrenedegrading strain;culture conditions;biodegradation;fluoranthene;pyrene
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发布时间：2023-12-11 - 摘要：The interannual variability of heavy rainfall during the first rainy season in Huizhou and its circulation characteristics are investigated by using the daily precipitation data and NCEP/NCAR reanalysis data from 1967 to 2009. The results show that Huizhou is characterized by large amounts of total precipitation, heavy precipitation amount and rainstorm days. Heavy precipitation and rainstorm days are basically in agreement with the time series of the total precipitation. All of their tendency have little change. However, the anomalous heavy rainfall events tend to increase and intensify from middle 1990s up to the present. Coherent changes in atmospheric circulation are identified in tropical and midlatitude systems. Southerly (northeasterly) anomalies prevail over the low latitude region before and after the climate jump when heavy rainfall events increase (decrease) and intensify (weaken). However, northerly anomalies and cold air are responsable for the increase and intensification in heavy rainfall after middle 1990s. Moreover, with stronger updraft, convective instability, the heavy rainfall is favorable to form and increase after middle 1990s in Huizhou. The situation of decrease and weakening in heavy rainfall is accompanied by stronger northerly anomalies, weaker updraft and convective instability after middle 1990s.关键词：climatology;heavy rainfall;climate jump;circulation characteristics
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发布时间：2023-12-11 - 摘要：Based on the physical mechanism of light transmission in water, the concept of water optical thickness is introduced into the transmission study, and then an integrated model for quantitatively calculating water depth by using remote sensing techniques was presented in this paper. Take Felaixia reservoir in Guangdong as a case study in this paper. Firstly, SPOT5 remote sensing data through radiation correction and atmospheric correction were converted into reflectance image in accordance with actual surface reflectance. Secondly, the information of waters was extracted by comparing the spectra of waters and lands, and then optical parameters of waters were substituted into the integrated models, selecting the appropriate bands of remote sensing, for calculating the water depths. Finally, the calculated water depths were input drawing software to generate the remote sensing map of water depths. The influence of sand mining and cage culture, such as turning muddy and high chlorophyll concentration of the reservoir waters, on the precision of water depth information has been considered in the model building in this paper, and hence multispectral remote sensing data were successfully applied to improve the calculation accuracy．关键词：water depth;physical model;feilaixia reservoir;SPOT5
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发布时间：2023-12-11 - 摘要：Based on a 3D hydrodynamic model developed on SELFE, the tidal energy fluxes and dissipation of the Pearl River estuary were discussed. The results showed that the tidal energy flux distribution corresponded to the topography beneath water in the estuary, and the Pearl River estuary can be divided into four zones: LingdingyangHumen zone, Modaomen estuary zone, HuangmaohaiTanjiang zone, and river net zone. There existed a hot spot zone (called “men” in Chinese) with high energy dissipation, about 1~2 order magnitude higher than the nearby water area, in these zones.
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发布时间：2023-12-11
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