Identification of Chinese green tea (Camellia sinensis) marker metabolites using GC/MS and UPLC-QTOF/MS

Food Science and Biotechnology - Tea is one of the most widely consumed aromatic beverages in the world because of its taste and flavor, as well as due to many potential health beneficial...     

Spatial-temporal graph neural network for traffic forecasting: An overview and open research issues

Applied Intelligence - Traffic forecasting plays an important role of modern Intelligent Transportation Systems (ITS). With the recent rapid advancement in deep learning, graph neural networks...     

A Lane-Level Road Marking Map Using a Monocular Camera

The essential requirement for precise localization of a self-driving car is a lane-level map which includes road markings (RMs). Obviously, we can build the lane-level map by running a mobile mapping system (MMS) which is equipped with a high-end 3D LiDAR and a number of high-cost sensors. This approach, however, is highly expensive and ineffective since a single high-end MMS must visit every place for mapping. In this paper, a lane-level RM mapping system using a monocular camera is developed. The developed system can be considered as an alternative to expensive high-end MMS. The developed RM map includes the information of road lanes (RLs) and symbolic road markings (SRMs). First, to build a lane-level RM map, the RMs are segmented at pixel level through the deep learning network. The network is named RMNet. The segmented RMs are then gathered to build a lane-level RM map. Second, the lane-level map is improved through loop-closure detection and graph optimization. To train the RMNet and build a lane-level RM map, a new dataset named SeRM set is developed. The set is a large dataset for lane-level RM mapping and it includes a total of 25157 pixel-wise annotated images and 21000 position labeled images. Finally, the proposed lane-level map building method is applied to SeRM set and its validity is demonstrated through experimentation.      

韩江河底隧道预灌浆区的强度时间相关特性

作为防水、防腐和地基加固等多种目的和手段之一,灌浆技术可应用于河底隧道或者海底隧道。水泥作为灌浆的主要材料具有强度时间相关特性。可是目前在大部分河底隧道在设计中不考虑水泥的这种强度时间相关特性。据此,提出以弹性波测试方法获得河底隧道施工中预注浆的强度时间相关特性,并采用数值模拟方法将获得的强度时间相关特性用于评价河底隧道的施工。为了获得预注浆区域的强度时间相关特性,进行了弹性波试验。然后把试验获得的预注浆区域的强度时间相关特性用于隧道施工仿真。计算结果表明,预注浆区域的强度时间相关特性不会对河底隧道的安全产生太大的影响。在模拟河底隧道施工时,发现其强度可以使用2～7d的预注浆区域的强度。分析结果也表明,通过强度和刚度的折减可模拟其强度时间相关特性。通过试验和数值模拟相结合的方式,提出预注浆区域的强度时间相关特性对河底隧道影响的方法,可为隧道工程的施工提供参考。     

The adverse effects of fine particle air pollution on respiratory function in the elderly

There is increasing concern that airborne particles are critical risk factors for adverse health conditions in susceptible populations. The objective of this panel study is to investigate an association between particulate matter and the peak expiratory flow rate (PEFR) in the elderly and to compare estimated risks using PM10 or PM2.5 levels as a measure of exposure. During a 2-year longitudinal follow-up study, we contacted subjects living in an asylum for the elderly, provided them with a mini-Wright peak flow meter, and instructed to record all the flow readings, any respiratory symptoms, passive smoking activity, and hours spent outdoors for that given day. Daily levels of particulate matter were measured by two separate mini-volume air samplers (for PM10 and PM2.5) placed on the rooftop of the two-story residence asylum building. In our statistical models, we assumed that the expected response varied linearly for each participant with a slope and intercept that depended on fixed or time-varying covariates using a mixed linear model. The daily mean levels of PM10 and PM2.5 were 78 microg/m3 and 56 microg/m3, respectively. For every 10 microg/m3 increase in PM10 and PM2.5 levels, there was an estimated PEFR change of -0.39 l/min (95% CI, -0.63, -0.14) and -0.54 l/min (95% CI, -0.89, -0.19), respectively. These data also suggest that fine particles have a more adverse respiratory health impact for sensitive individuals such as the elderly and that more research and control strategies should focus on the smaller particles associated with air pollution.     

A framework for rapid local area modeling for construction automation

Rapid 3D positioning and modeling in construction can be used to more effectively plan, visualize, and communicate operations before execution. It can also help to optimize equipment operations, significantly improve safety, and enhance a remote operator's spatial perception of the workspace. A new framework for rapid local area sensing and 3D modeling for better planning and control of construction equipment operation is described and demonstrated. By combining human-assisted graphical workspace modeling with pre-stored Computer-Aided Design (CAD) models and simple sensors (such as single-axis laser rangefinders and remote video cameras), modeling time can be significantly reduced while potentially increasing modeling accuracy.     

Prediction of the combination of failure modes for an arch bridge system

An innovative prediction method for the combination of failure modes of an arch bridge is proposed for its probabilistic risk assessment and is compared with the conventional system reliability analysis method. The suggested method reveals various combinations of failure modes in significantly reduced time and efforts in comparison to the previous permutation method or the conventional system reliability analysis method. Additionally, the suggested method can be used for the verification of the system reliability with more specific predictions of the failure modes.Component reliabilities of girders have been evaluated by using response surfaces of the design variables at the selected critical sections, i.e. the maximum shear and negative moment locations. Response Surface Method (RSM) is successfully applied for the reliability analyses of complex structure with relatively small probability of failure. Previous methods such as Monte Carlo Simulations or First Order Second Moment method cannot easily calculate the derivative terms of implicit limit state functions. Hence, the target bridge system is modeled as a series-connection system for the analysis of its system reliability. The upper and lower bound of the probabilities of failure for the structural system have been evaluated and are compared with the suggested prediction method for all possible combination of failure modes.     

Phosphorous retention capacity of filter media for estimating the longevity of constructed wetland

The filter medium could be selected and the longevity of the filter medium by the phosphorus saturation could be predicted in the constructed wetland system, accordingly proposing the scheme to remove the phosphorus for a long period. The phosphorus adsorption capacities of various filter media were investigated in relation to the size and types of filter media to screen the optimal condition. The objective of this study was to evaluate the constructed wetland longevity by improving P adsorption capacity. The maximum P adsorption capacities of filter media A (4--10 mm), B (2--4 mm), and C (0.1--2 mm) were 7.7, 11.6, and 22.5 mg/kg, respectively, showing that they increased as the filter media size decreased. Among the experimental media, the optimal filter media size was 0.1--2 mm. When Ca, Mg, Al and Fe were added to the filter medium C, which is the optimal filter medium, the addition of Ca improved mostly the P adsorption capacity. In the alternative proposal to use these facts, the oyster shell was added to the filter medium and the P adsorption capacity was examined: adding 2% oyster shell increased the P adsorption capacity from 23 to 36 mg/kg. In the column where the oyster shell was mixed, when the oyster shell content was 5%, 10%, 20%, 40%, 60%, 80%, and 100% in the filter medium C, the respective saturation times of the P adsorption were about 6, 9, 17, 30, 43, 56, and 70 days. When the oyster shell content was 0%, 5%, 10%, 20%, 40%, 60%, 80%, and 100% after 1 month in the column, the P adsorption amount was about 180, 600, 1560, 4280, 6157, 7089, 7519, and 7925 mg/kg, respectively. The increment of the P adsorption amount was small if the oyster shell content was 60% or more, because the filter medium with more than 60% oyster shell content did not approach the saturation time by the P adsorption yet. The P adsorption amount for 60%, 80%, and 100% could be predicted as about 9702, 12,879, and 16,056 mg/kg, respectively. The largest amount of extracted P in the filter media with oyster shell after 30 days of P solution application was bound to Ca, followed by water soluble-P, Al--P, and Fe--P. Therefore, it was concluded that the adsorption amount of the phosphorus could be increased by adding the oyster shell to the filter medium. Also, it was concluded that adding the oyster shell to the filter medium in the constructed wetland was the scheme to extend the longevity of the constructed wetland by the phosphorus saturation, and using the oyster shell would be useful in aspect of economical efficiency and easiness. Especially, it would be the alternative proposal to reduce the environmental pollution in aspect of recycling wastes.     

Sorbed atrazine shifts into non-desorbable sites of soil organic matter during aging

Soil-chemical contact time (aging) is an important determinant of the sorption and desorption characteristics of the organic contaminants and pesticides in the environment. The effects of aging on mechanism-specific sorption and desorption of atrazine were studied in soil and clay slurries. Sorption isotherm and desorption kinetic experiments were performed, and soil-water distribution coefficients and desorption rate parameters were evaluated using linear and non-linear sorption equations and a three-site desorption model, respectively. Aging time for sorption of atrazine in sterilized soil and clay slurries ranged from 2 days to 8 months. Atrazine sorption isotherms were nearly linear (r(2)>0.97) and sorption coefficients were strongly correlated to soil organic carbon content. Sorption distribution coefficients (K(d)) increased with increase in age in all five soils studied, but not for K-montmorillonite. Sorption non-linearity did not increase with increase in age except for the Houghton muck soil. Desorption profiles were well described by the three-site desorption model. The equilibrium site fraction (f(eq)) decreased and the non-desorbable site fraction (f(nd)) increased as a function of aging time in all soils. For K-montmorillonite, f(nd) approximately 0 regardless of aging, showing that aging phenomena are sorbent/mechanism specific. In all soils, it was found that when normalized to soil organic matter content, the concentration of atrazine in desorbable sites was relatively constant, whereas that in non-desorbable site increased. This, and the lack of aging effects on desorption from montmorillonite, suggests that sorption into non-desorbable sites of soil organic matter is primary source of increased atrazine sorption in soils during aging.     

汉城数字媒体城市的规划与城市设计

本文介绍了位于韩国汉城“新千年城”中的“数字媒体城市”项目（以下简称DMC）的规划过程、规划概念，并分析其规划控制与城市设计。