curve

摘要： 为了提高夜间疲劳驾驶检测的准确率,在现有低光增强算法Zero-DCE(Zero-Reference Deep Curve Estimation)的基础上,提出改进Zero-DCE的低光增强算法。首先,引入上下采样结构,减少噪声影响。同时,引入注意力门控机制,提高网络对图像中人脸区域的敏感性,有效提高网络的检测率。然后,针对噪声相关问题,提出改进的核选择模块。进一步,使用MobileNet的深度可分离卷积替换Zero-DCE的标准卷积,提高网络的检测速度。最后,通过人脸关键点检测网络和分类网络,判断驾驶员的疲劳状态。实验表明,在夜间环境下,相比现有的疲劳驾驶检测算法,文中算法在人脸检测的准确率和眼睛状态的识别率上都有所提升,取得较令人满意的检测效果。

摘要： Incremental dynamic analysis and nonlinear static pushover analysis are carried out on a performance-based design to determine the seismic demands and capacities of an elliptic braced moment resisting frame(ELBRF).The objective is to assess ductility,overstrength and response modification factors in a modern steel-braced structural system based on incremental dynamic analysis.This integrated system is connected to a beam and column with an appropriate length while providing enough architectural space to allow for an opening without having the common problems associated with architectural spaces in braced systems.Several different classes of buildings are considered on soil type II.Linear dynamic analysis,nonlinear static pushover analysis and incremental nonlinear dynamic analysis related to 12 records from past earthquakes are carried out using OpenSees software.The factors of ductility,overstrength and response modification are calculated for this system.The values of 9.5 and 6.5 are found and suggested only for the response modification factor for ELBRF systems in allowable stress and ultimate limit state methods,respectively.The fragility curves are plotted for the first time for this type of bracing,which contributes to the assessment of building seismic damage.

摘要： 在高温环境下工作时,人们需要穿着专用服装以避免灼伤.专用服装通常由三层织物材料构成,记为I、II、III层,其中I层与外界环境接触,III层与皮肤之间还存在空隙,将此空隙记为IV层.为设计这种专用服装,将体内温度控制在37°C的假人放置在实验室的高温环境中,对环境温度为75°C、II层厚度为6mm、IV层厚度为5mm、工作时间为90min的情形开展实验,测量得到假人皮肤外侧的温度.为了降低研发成本、缩短研发周期,可以通过数学建模确定假人皮肤外侧的温度变化情况,并解决相关问题.

摘要： By taking into account the relative energy between the diquark and the quark in nucleons, the gravitational singularity in a black hole created from a collapsing neutron star can be removed;compatibility with quantum mechanics is restored. This black hole becomes a “black” neutron star. The negative relative energy identified as dark matter in the previous paper can account for the galaxy rotation curve. The positive relative energy identified as dark energy in the previous paper can explain the accelerating expansion of the universe. A possible scenario for cosmic ray generation is given.

摘要： Motivated by the search for ways of a more efficient usage of the ubiquitous, and unexploited resources of methane, recent progress in the gas-phase activation of methane by metal dication complex ion is discussed. The gas phase theoretical and experimental analysis on [Pb(Benzene)2]2+ was conducted. The [Pb(Benzene)2]2+ complex ions were prepared using a combination of the pick-up technique and high energy electron impact, and then held in a cold ion trap. Excitation with tuneable UV radiation resulted in the formation of [Pb(Benzene)2(H2O)]2+, [Pb(Benzene)2(H2O)2]2+, [Pb(Benzene)]+, Pb+ and Benzene+ ions when the experimental results were analysed. The two optimised geometries of [Pb(Benzene)2]2+ namely the C2V eclipse and C2 staggered were observed. Methane activation of [Pb(Benzene)2]2+ complex ion yielded [Pb(Benzene)2(Me)]2+. [Pb(Benzene)2(H2O)(Me)2]2+,? [Pb(Benzene)2(H2O)(Me)]2+, [PbBenzene(Me)3]2+ and [Pb(Benzene)(Me)]2+. The PEC calculated binding energy of methane to lead benzene dication complex ion was approximately 25.45% higher than the value recorded on DFT calculation. This difference was due to the charge differences on the lead metal centre. While the actual calculated charge on the Pb metal in the optimised geometry was 1.68 the charge of +2 on the Pb metal was considered in the PEC calculation.

摘要： In this paper, we use a Circle Restricted Three-Body Problem (CRTBP) to simulate the motion of a satellite. Then we reformulate this problem with the controller into the description using Koopman eigenfunction. Although the original dynamical system is nonlinear, the Koopman eigenfunction behaves linearly. Choosing Jacobi integral as the Koopman eigenfunction and using the zero velocity curve as the reference for control, we are allowed to combine well-developed Linear Quadratic Regulator (LQR) controller to design a nonlinear controller. Using this approach, we design the low thrust orbit transfer strategy for the satellite flying from the earth to the moon or from the earth to the sun.

摘要： The proof of the Jordan Curve Theorem (JCT) in this paper is focused on a graphic illustration and analysis ways so as to make the topological proof more understandable, and is based on the Tverberg’s method, which is acknowledged as being quite esoteric with no graphic explanations. The preliminary constructs a parametrisation model for Jordan Polygons. It takes quite a length to introduce four lemmas since the proof by Jordan Polygon is the approach we want to concern about. Lemmas show that JCT holds for Jordan polygon and Jordan curve could be approximated uniformly by a sequence of Jordan polygons. Also, lemmas provide a certain metric description of Jordan polygons to help evaluate the limit. The final part is the proof of the theorem on the premise of introduced preliminary and lemmas.

摘要： Nutrient loads into water resources continues to be a major problem in Southern Africa. This has resulted in significant compromises in the ecological integrity of freshwater resources. The study aimed to assess the pollution load into the Elands River in terms of nitrates and orthophosphates. These variables were compared against the Crocodile Catchment Interim Resource Quality Objectives to determine compliances or non-compliance of the Waterval Boven wastewater treatment plant. Generally upstream nitrate levels did not exceed the ideal limit of 0.5 mg·l-1 as indicated in the 2015 to 2016 samples where values ranged between 0.32 mg·l -1 and 0.27 mg·l-1, respectively. Similarly, observed upstream orthophosphates levels were below the ideal limit of 0.03 mg·l-1. However, downstream values of both nutrients exceeded the respective set limits. The nutrient load contribution from the sewage plant was characterised by a simple point-source model. Patterns of the loads into the river were demonstrated on a load duration curve based on the river which equalled or exceed 0.18 m3/s upstream and 1.31 m3/s downstream at 90% of the time. However, the flows were regarded as significantly low to deal with uncontrolled pollution loads. Most of the observed loads fell below the ideal limit of 0.05 mg·l-1 for nitrates both upstream and downstream of the sewage plant. For orthophosphates, most of the upstream loads were below the tolerable limit of 0.1 mg·l-1 whilst the downstream loads were exceeding the tolerable limits. The higher loads downstream in the river were attributed to the sewage discharge from the Waterval Boven wastewater treatment plant and the low river flows. Hence it could be concluded that river water quality should be interpreted based on the river flow regime in a given season.

摘要： Background: The multiple sequence alignment (MSA) algorithms are the traditional ways to compare and analyze DNA sequences. However, for large DNA sequences, these algorithms require a long time computationally. Objective: Here we will propose a new numerical method to characterize and compare DNA sequences quickly. Method: Based on a new 2-dimensional (2D) graphical representation of DNA sequences, we can obtain an 8-dimensional vector using two basic concepts of probability, the mean and the variance. Results: We perform similarity/dissimilarity analyses among two real DNA data sets, the coding sequences of the first exon of beta-globin gene of 11 species and 31 mammalian mitochondrial genomes, respectively. Conclusion: Our results are in agreement with the existing analyses in our literatures. We also compare our approach with other methods and find that ours is more effective.

摘要： The non-rectangular hyperbola(NRH)equation is the most popular method that plots the photosynthetic light-response(PLR)curve and helps to identify plant photosynthetic capability.However,the PLR curve can't be plotted well by the NRH equation at different plant growth phases due to the variations of plant development.Recently,plant physiological parameters have been considered into the NRH equation to establish the modified NRH equation,but plant height(H),an important parameter in plant growth phases,is not taken into account.In this study,H was incorporated into the NRH equation to establish the modified NRH equation,which could be used to estimate photosynthetic capability of herbage at different growth phases.To explore photosynthetic capability of herbage,we selected the dominant herbage species Potentilla anserina L.and Elymus nutans Griseb.in the Heihe River Basin,Northwest China as the research materials.Totally,twenty-four PLR curves and H at different growth phases were measured during the growing season in 2016.Results showed that the maximum net photosynthetic rate and the initial slope of PLR curve linearly increased with H.The modified NRH equation,which is established by introducing H and an H-based adjustment factor into the NRH equation,described better the PLR curves of P.anserina and E.nutans than the original ones.The results may provide an effective method to estimate the net primary productivity of grasslands in the study area.