Search

The quality of "non-landslide' samples data impacts the accuracy of geological hazard risk assessment. This research proposed a method to improve the performance of support vector machine (SVM) by perfecting the quality of `non-landslide' samples in the landslide susceptibility evaluation model through fuzzy c-means (FCM) cluster to generate more reliable susceptibility maps. Firstly, three sample selection scenarios for `non-landslide' samples include the following principles: 1) select randomly from low-slope areas (scenario-SS), 2) select randomly from areas with no hazards (scenarioRS), 3) obtain samples from the optimal FCM model (scenario-FCM), and then three sample scenarios are constructed with 10,193 landslide positive samples. Next, we have compared and evaluated the performance of three sample scenarios in the SVM models based on the statistical indicators such as the proportion of disaster points, density of disaster points precision, receiver operating characteristic (ROC) curve, and area under the ROC curve (AUC). Finally, The evaluation results show that the `non-landslide' negative samples based on the FCM model are more reasonable. Furthermore, the hybrid method supported by SVM and FCM models exhibits the highest prediction efficiency. Scenario FCM produces an overall accuracy of approximately 89.7% (AUC), followed by scenario-SS (86.7%) and scenario-RS (85.6%).

A large number of users’ microblogs and various Points of Interest (POIs) of public service facilities in social media provide abundant data resources for the emergency events detection, fusion ana...

Tailoring workshop (TW), a school-based teacher training program, has been developed in China on the basis of the Teaching Research Groups (TRGs) to better focus on teacher’s genuine needs, improve...

Indoor wayfinding is an important and complex daily activity. In this study, we aimed to explore the indoor wayfinding performance of pedestrians of different genders under time pressure. We conducted a wayfinding experiment in a real-world subway station in Beijing using eye-tracking and verbal protocol methods and analyzed wayfinding efficiency, strategies and eye movement data from 38 participants. The results indicated that both male and female participants experienced more difficulty reading maps under time pressure. We also found that males consistently had higher efficiency when they searched for information and could extract information from signage more efficiently than females when they were not under time pressure. Males were more adventurous and preferred to take risks under time pressure, while females consistently maintained a conservative strategy. These findings contribute to the understanding of gender differences in indoor wayfinding and cognition.

Landmark visual salience (characterized by features that contrast with their surroundings and visual peculiarities) and semantic salience (characterized by features with unusual or important meanin...

The postharvest performance of cut spray-type carnations (Dianthus caryophyllus L.) is often limited by the opening, longevity, and coloration of individual florets, and is apparently related to wa...

The L-band microwave has the ability for penetrating snow and sea ice, hence the potential for data retrieval of snow depth and sea ice thickness. The L-band radiometer Soil Moisture and Ocean Salinity has been applied to retrieve sea ice parameters using a L-band radiation model. Here, we improve the L-band radiation model in two ways. First, instead of a single layer, we reformulate the model to consider multiple layers for sea ice and snow to better characterize the radiative effect of vertical temperature and salinity profile within the sea ice and the snow cover. Second, we incorporate small-scale sea ice variability, sea ice leads, which are not distinguishable with the L-band satellite data but have profound impacts on the simulated brightness temperature. Small-scale features of the sea ice cover such as leads can significantly lower the overall brightness temperature (). The results show that the improved radiation model can correct sea ice type dependent biases of (R2 from 0.05 to 0.72) ...

The calculation of surface area is meaningful for a variety of space-filling phenomena, e.g., the packing of plants or animals within an area of land. With Digital Elevation Model DEM data we can calculate the surface area by using a continuous surface model, such as by the Triangulated Irregular Network TIN. However, just as the triangle-based surface area discussed in this paper, the surface area is generally biased because it is a nonlinear mapping about the DEM data which contain measurement errors. To reduce the bias in the surface area, we propose a second-order bias correction by applying nonlinear error propagation to the triangle-based surface area. This process reveals that the random errors in the DEM data result in a bias in the triangle-based surface area while the systematic errors in the DEM data can be reduced by using the height differences. The bias is theoretically given by a probability integral which can be approximated by numerical approaches including the numerical integral and the Monte Carlo method; but these approaches need a theoretical distribution assumption about the DEM measurement errors, and have a very high computational cost. In most cases, we only have variance information on the measurement errors; thus, a bias estimation based on nonlinear error propagation is proposed. Based on the second-order bias estimation proposed, the variance of the surface area can be improved immediately by removing the bias from the original variance estimation. The main results are verified by the Monte Carlo method and by the numerical integral. They show that an unbiased surface area can be obtained by removing the proposed bias estimation from the triangle-based surface area originally calculated from the DEM data.

Population spatialization is the foundation for the visualization and analysis of population integrated with other information, such as environmental resources, economy, and public health. The existing population spatialization models have solved many problems for population distribution, but most of these studies have focused on a specific, single-scale approach and ignored the scale transformation for population spatialization. However, multi-scale visualization and the analysis of spatial information need multi-scale information. Meanwhile, the population distribution map as one kind of thematic map is always overlaid with the digital vector map or remote sensing map and visualized in the Web Geographic Information Systems (Web GIS), so it should adapt to the map scale showed in browser, when the user zoom in and zoom out. Hence adaptive multi-scale is necessary for population spatialization. Therefore, in this study, an adaptive multi-scale population spatialization model (APSM) is proposed with compr...

Marangoni condensation attracts much attention in recent years. This study focused on the effect of tube diameters on Marangoni condensation heat transfer in the case of ethanol–water mixture vapors. Several tube outer diameters, including 0.793 mm, 1.032 mm, 1.221 mm, 10.0 mm, and 20.0 mm, were chosen to indicate the phenomenon, as well as the vertical plate. The ranges of the tube diameters were from macroscale to microscale. The experimental results showed that for pure steam the heat transfer coefficients monotonically increased with the decrease in diameters. For the ethanol–water mixture vapors, the reduction effect of liquid thickness and the accumulation effect of condensate liquid jointly influenced the heat transfer. In the case of macrosurfaces, the promotion effect caused by diameter decrease played a dominant role, and the heat transfer coefficients increased with decreasing the diameters. In the case of microsurfaces, the negative effect of condensate liquid accumulation became active and wa...

Lignite is becoming a competitive fuel for power generation with high security of supply and a low price. But a power plant firing lignite directly always has some weaknesses, including low thermal...

Lignite is becoming a competitive fuel for power plants, offering very high security of supply and cost-effectiveness. However, power plants firing lignite face some thorny issues, such as high carbon dioxide emissions, high investment in construction, etc. Lignite pre-drying is considered an attractive way to tackle these issues, but it consumes a lot of energy and has a high risk of ignition. Thus, a combined-type fluid-bed dryer, with which lignite could be dried safely using some waste from a power-generation process, is proposed in this paper. Both boiler exhaust flue gas and steam extraction of steam turbines are used as heat sources for this kind of dryer. To analyze its thermodynamics, a theoretical model was developed with which a reference case of a 1000 MW air-condensing power plant was performed. The results show that a dryer integrated within the power plant can evidently increase the plant efficiency by approximately 2.55%. The main factors, including the degree of pre-drying, dryer thermal ...

Increasing production and recovery from the mature oil and gas fields often requires a boosting system when the gas pressure is lower than that demanded by the transportation or process system. The supersonic ejector, considered to be a cost-effective way to boost the production of a low-pressure gas well, was introduced into the industrial field. However, the exploitation of natural gas often accompanies with water. The computational fluid dynamics (CFD) technique was employed to investigate the two-phase effect (water droplets) on the performance of natural gas ejector for the motive pressure ranging from 11.0 MPa to 13.0 MPa, induced pressure from 3.0 MPa to 5.0 MPa, and backpressure from 5.1 MPa to 5.6 MPa, while the injected water flow rate was less than 0.03 kg s−1. The numerical results show that the entrainment ratio of the two-phase operation was higher than that of the single-phase operation with the variation of backpressure. Meanwhile, the entrainment ratio increased with the increase of injec...

Curcuma longa Linn. (CLL) is widely used as a traditional herbal medicine for the prevention of diabetic vascular complications, but the potential active compounds and its bioaffinity property to cells remain obscure. In this study, cell membrane chromatography (CMC) was used to screen the active components binding to human umbilical vein endothelial cells (HUVECs). Demethoxycurcumin and curcumin in CLL were identified as two cells-binding compounds. MTT and acridine orange-ethidium bromide (AO-EB) results demonstrated demethoxycurcumin and curcumin had protection activity on advanced glycation end products (AGEs)-induced HUVECs damage, including increasing cell viability and reducing apoptosis. CMC was also used to determine the bioaffinity property of these compounds to cells. The dissociation equilibrium constants (Kd) of demethoxycurcumin and curcumin were 3.173 ± 0.46 and 3.088 ± 0.51 nM. Maximum binding capacities (Bmax) were 22.61 ± 3.74 and 24.39 ± 2.11 fmol · mg−1 protein. The IC50 of demethoxycu...

In this article, organomodified montmorillonite (OMMT) was applied as synergistic agent in Polypropylene(PP)/Ammonium polyphosphate (APP)/Elastomer containing silicon(Si-E)system. The effect of OMMT on this system was investigated by thermo gravimetric. analysis (TGA), Fourier transform infrared spectrometer (FT-IR), scanning electron microscopy (SEM) and limited oxygen index (LOI). The results show that the flame-retardancy properties of PP/APP/Si-E composites enhanced in the presence of OMMT. LOI was enhanced slightly and the char residue was increased. The impact strength of the PP composite was significantly improved after adding OMMT. The weight loss difference shows that there was a synergetic interaction between OMMT and PP/APP/Si-E composite.

An experimental investigation was carried out to find the lifting-pressure performance of a steam-driven jet injector for various configuration parameters. The pressure profiles along the mixing chamber were measured with constant inlet steam and water parameters; the results indicated that the injector had a self-adaptive characteristic and the outlet water mass flow rate had an invariable characteristic. The lifting-pressure coefficient was affected significantly by the area ratio of the secondary nozzle and area ratio of the mixing chamber, and the influences were discussed. Moreover, the pressure distribution characteristic of a supersonic steam jet in water was studied under different steam pressures and water temperatures. The results indicated that the pressure distributions were affected by flow and condensation characteristics that were described by steam pressure and water temperature; the maximum axial pressure ratio was also discussed. Predictions of the distance of the maximum axial pressure ...

Considering the low efficiency and accuracy of existing straight line extraction methods from large-scale imagery, a multi-scale Hough transform HT method based on the pre-storage weight matrix is proposed. Improvements of the proposed HT include: using the pre-storage weight matrix to save storage space and improve the efficiency of the HT, applying a multi-scale method to enable the detection of smaller features from large-size images, using overlapping adjacent tiles to avoid the fragmented lines, optimizing the dimensions of the discrete transform domain, normalizing the accumulator to extract off-centred lines and using a dual threshold for distributed line detection. The experimental results show that the proposed algorithm is not only more efficient and robust but also can obtain richer and more accurate information about features, especially for large-size images.

Satellite-based sea surface temperature (SST) measurements in the Southern Hemisphere from the Advanced Very High Resolution Radiometer (AVHRR), Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) and Tropical Rainfall Measuring Mission Microwave Imager (TMI) are compared with in-situ SST measurements obtained from the Chinese National Antarctic Research Expeditions (CHINARE) for the period 1989-2005. Relative to the ship observations, which ranged from the tropics to the Southern Ocean, the AVHRR SST has a mean bias/root mean square error (RMSE) of -0.11°C/0.89°C (-0.04°C/0.93°C for daytime and -0.21°C/0.84°C for night-time), the AMSR-E SST has a mean bias/RMSE of 0.39°C/0.86°C (0.46°C/0.91°C for daytime and 0.32°C/0.80°C for night-time), and the TMI SST has a mean bias/RMSE of 0.63°C/1.28°C (0.57°C/1.23°C for daytime and 0.69°C/1.36°C for night-time). In the Southern Ocean, the AVHRR SST shows persistent cold biases during the daytime and night-time, while the opposite is the case for AMSR-E and TMI SSTs. A discussion of the dependence of the SST biases in the presence of the varying ship SST, surface wind speed and atmospheric water vapour is presented. Additionally, the consistency between microwave and infrared SST is examined to identify regimes that are associated with the observed differences.

The objectives of the present study are to investigate the effect of plasticizer type and level on the curing of cellulose acetate phthalate (CAP) coated beads with and without the presence of humidity. Theophylline beads were coated in a fluidized-bed with CAP dispersion (Aquacoat CPD) plasticized by a water-insoluble plasticizer, diethyl phthalate (DEP), or a water-soluble plasticizer, triethyl citrate (TEC), at various levels. The coated heads were cured at a heat-only condition (50 degrees C for 24 hr) and a heat-humidity condition (50 degrees C/75% RH for 24 hr). Rapid drug release in the acidic media was found for both heat-only and heat-humidity cured beads when plasticizer was not used in the coating dispersion, indicating that the heat-humidity curing is ineffective without the presence of plasticizers. When plasticizer was incorporated in the coating formulations, heat-humidity curing effectively improved the acid resistance of the coated films at all plasticizer levels investigated. The minimum plasticizer level required to obtain enteric release profiles for heat-humidity cured beads coated at an outlet coating temperature of 46 degrees C was 15%. This limit was further decreased when the beads were coated at a lower temperature due to a less plasticizer loss at the lower coating temperature. Between the two plasticizers, less TEC was lost during the coating process, and TEC was more effective compared to DEP with regards to heat-humidity curing at the 10% plasticizer level. The enteric release profiles were reproducible following a 7-day drying period at 40 degrees C for all heat-humidity cured beads that had initially passed the enteric release dissolution test. The rapid leaching of TEC and DEP into the.