A meshfree-based local Galerkin method with condensation of degree of freedom for elastic dynamic analysis

Condensation technique of degree of freedom is first proposed to improve the computational efficiency of meshfree method with Galerkin weak form for elastic dy- namic analysis. In the present method, scattered nodes with- out connectivity are divided into several subsets by cells with arbitrary shape. Local discrete equation is established over each cell by using moving Kriging interpolation, in which the nodes that located in the cell are used for approxima- tion. Then local discrete equations can be simplified by con- densation of degree of freedom, which transfers equations of inner nodes to equations of boundary nodes based on cells. The global dynamic system equations are obtained by as- sembling all local discrete equations and are solved by using the standard implicit Newmark＇s time integration scheme. In the scheme of present method, the calculation of each cell is carried out by meshfree method, and local search is imple- mented in interpolation. Numerical examples show that the present method has high computational efficiency and good accuracy in solving elastic dynamic problems.

Method for Evaluating the Degrees of Land Use Sustainability of Mountainous County and its Application in Yunnan Province,China

The evaluation of sustainable land use is the key issue in the field of studying the sustainable land utilization. In general analysis, the sustainable land use is evaluated respectively from its ecological sustainability, economic sustainability and social sustainability in China and other countries in recent years. Although this evaluation is an important work, it seems insufficient and hard to comprehensively reflect the whole degree of land use sustainability. Thus, to make up this deficiency, this paper brings forward the evaluation indexes, which make it possible to quantitatively reflect the whole degree of land use sustainability, namely, the concept of "degrees of overall land use sustainability" (DOS), and research and development of the method of measurement and calculation in DOS. Taking the evaluation of the degree of land use sustainability in county regions of Yunnan Province as the actual example for analysis, results are basically as follows:1) The degree of land use sustainability (DOS) is the ration index to organically and systematically integrate the degree of ecological friendliness (DEF), the degree of economic viability (DEV) and the degree of social acceptability (DSA), able to comprehensively reflect the whole sustainability degree of regional land use. 2) Based on the value of DOS, the grading system and standard for the sustainability of land use may be established and totally divided into five grades, namely, the high-degree sustainability, middle-degree sustainability, low-degree sustainability, conditional sustainability and non-sustainability. Meanwhile, the standard for distinguishing sustainability grades has also been confirmed so as to determine the nature of sustainability degrees in different grades. This makes the possibility for the combination of nature determination with ration in research result and provides with the scientific guideline and decision-making gist for better implementation of sustainable land use strategy.3) The practice in evaluation of sustainability degree in county regional land use in Yunnan shows that the value of the degree of land use sustainability (DOS) of whole Yunnan Province is only 58.39, belonging to the grade of low-degree sustainability. Two thirds of counties in the whole province represent the grade of "conditional sustainability" and "non-sustainability" in the sustainability of land use. Among these counties, 11.11 % shows "non- sustainability". The lowest degree of land use sustainability appears especially in the middle plateau mountain region of Northeast Yunnan, where the value of DOS in most counties (districts) is below 40 %, belonging to the grade of "non-sustainability". The sustainability degree in the karst mountainous region in lower-middle plateau mountain region in Southeast Yunnan is generally low and the value of sustainability degree (DOS) in most of the counties (cities and districts) is below 55. The value of sustainability degree (DOS) in most of the counties (cities and districts) in the north, west, northwest and southwest parts of Yunnan is below 55. This article also analyzes the reasons of low degree of sustainability in land use in Yunnan and puts forward the countermeasures to increase the degree of sustainability in land use in the whole province.

Hazard degree identification of goafs based on scale effect of structure by RS-TOPSIS method

In order to precisely predict the hazard degree of goaf(HDG), the RS-TOPSIS model was built based on the results of expert investigation. To evaluate the HDG in the underground mine, five structure size factors, i.e. goaf span, exposed area, goaf height, goaf depth, and pillar width, were selected as the evaluation indexes. And based on rough dependability in rough set(RS)theory, the weights of evaluation indexes were identified by calculating rough dependability between evaluation indexes and evaluation results. Fourty goafs in some mines of western China, whose indexes parameters were measured by cavity monitoring system(CMS), were taken as evaluation objects. In addition, the characteristic parameters of five grades' typical goafs were built according to the interval limits value of single index evaluation. Then, using the technique for order preference by similarity to ideal solution(TOPSIS), five-category classification of HDG was realized based on closeness degree, and the HDG was also identified.Results show that the five-category identification of mine goafs could be realized by RS-TOPSIS method, based on the structure-scale-effect. The classification results are consistent with those of numerical simulation based on stress and displacement,while the coincidence rate is up to 92.5%. Furthermore, the results are more conservative to safety evaluation than numerical simulation, thus demonstrating that the proposed method is more easier, reasonable and more definite for HDG identification.

Optimization of construction machinery scheme of cast-in-situ concrete based on the improved scatter degree method

The basic requirement of mechanical construction of cast-in-situ concrete is that it could not only conduct quality qualification and safety production, but also achieve most economic benefits with less investment under the condition to meet the needs of project duration. Therefore, the selection of construction machinery scheme plays an important role. However, in the actual construction, it is usually that operators rely on their own experience and field conditions to determine the mechanics. Such a method is subjective and arbitrary, and it is not conducive to make the construction rationally. Considering the above reasons, an improved weight coefficient method was used to establish an estimation model to estimate the construction machinery scheme of cast-in-situ concrete, so as to make the procedure much rational.

Primary resonance of multiple degree-of-freedom dynamic systems with strong non-linearity using the homotopy analysis method

A homotopy analysis method（HAM）is presented for the primary resonance of multiple degree-of-freedom systems with strong non-linearity excited by harmonic forces.The validity of the HAM is independent of the existence of small parameters in the considered equation.The HAM provides a simple way to adjust and control the convergence region of the series solution by means of an auxiliary parameter.Two examples are presented to show that the HAM solutions agree well with the results of the modified Linstedt-Poincar＇e method and the incremental harmonic balance method.

Formula for calculating spatial similarity degrees between point clouds on multi-scale maps taking map scale change as the only independent variable

The degree of spatial similarity plays an important role in map generalization, yet there has been no quantitative research into it. To fill this gap, this study first defines map scale change and spatial similarity degree/relation in multi-scale map spaces and then proposes a model for calculating the degree of spatial similarity between a point cloud at one scale and its gener- alized counterpart at another scale. After validation, the new model features 16 points with map scale change as the x coordinate and the degree of spatial similarity as the y coordinate. Finally, using an application for curve fitting, the model achieves an empirical formula that can calculate the degree of spatial similarity using map scale change as the sole independent variable, and vice versa. This formula can be used to automate algorithms for point feature generalization and to determine when to terminate them during the generalization.

From Pythagoras Theorem to Fermat’s Last Theorem and the Relationship between the Equation of Degree <i>n</i>with One Unknown

The most interesting and famous problem that puzzled the mathematicians all around the world is much likely to be the Fermat’s Last Theorem. However, since the Theorem was proposed, people can’t find a way to solve the problem until Andrew Wiles proved the Fermat’s Last Theorem through a very difficult method called Modular elliptic curves in 1995. In this paper, I firstly constructed a geometric method to prove Fermat’s Last Theorem, and in this way we can easily get the conclusion below: If a and b are integer and?a = b, n ∈ Q and n > 1, the value of c satisfies the function an + bn = cn that can never be integer;if a, b and c are integer and a ≠ b, n is integer and n > 2, the function an + bn = cn cannot be established.

Graphlet Degree Vector方法的优化与并行

Graphlet Degree Vector(GDV)是一种研究生物网络的重要方法,能揭示生物网络中各节点与其局部网络结构的相关性,但随着需要挖掘的自同构轨道数量的增加以及生物网络规模的增大,GDV方法的时间复杂度会呈指数级增长。针对这个问题,在现有串行GDV方法的基础上,实现了基于消息传递接口(MPI)的GDV方法并行化;此外又将GDV方法进行了改进并将改进后的方法实现了并行优化,改进后的方法在寻找不同节点自同构轨道的过程中优化了计算过程以解决重复计算的问题,同时结合负载均衡策略合理分配任务。模拟网络数据和真实生物网络数据上的实验结果表明,并行化的GDV方法与改进后的并行化GDV方法都具有较好的并行性能,并且对不同类型不同规模的网络都具有较强的适用性,扩展性强,可有效地保持寻找网络中自同构轨道的高效率。

Quality Evaluation of Urban Pseudo Habitat Environments Based on the Degree of Public Praise from dianping.com:A Case Study of Liaoning Province

Due to the continuous development of information technology, people's perception of real life is more based on the information acquired on the real environment with the help of various media, rather than intuition. Based on priority evaluation data obtained from dianping.com(Liaoning Province), and the established criteria for assessing pseudo habitat environment quality, this study uses the entropy method to calculate and rank the comprehensive score of each merchant's word-of-mouth evaluation. It analyzes the spatial pattern and differentiation characteristics of pseudo environment quality, as well. Results show that:(1) The overall quality scores of the pseudo living environment in southern, central, and northern Liaoning are higher than those in eastern and western area. The pseudo habitat environment quality score of coastal cities is relatively higher than that of inland cities; and that of cities with high resource depletion is lower.(2) Parent-child activity, learning and training, and sports & health have significant impact, whereas hotels and peripheral tours have less impact on the pseudo habitat environment quality in Liaoning province. The overall pseudo habitat environment quality score of a city is inversely proportional to the total scores of various indicators in the city.(3) The spatial distribution of pseudo habitat quality in Liaoning Province shows a "saddle" structure. The spatial heterogeneity of the pseudo habitat environment in central and northern Liaoning areas is larger than that in eastern, western, and southern areas of Liaoning. The degree of quality of the pseudo habitat environment is proportional to the size of its spatial differentiation degree in total.

Subharmonic response of single-degree-of-freedom linear vibroimpact system to narrow-band random excitation

The subharmonic response of a single-degree-of-freedom linear vibroimpact oscillator with a one-sided barrier to the narrow-band random excitation is investigated.The analysis is based on a special Zhuravlev transformation,which reduces the system to the one without impacts or velocity jumps,and thereby permits the applications of asymptotic averaging over the period for slowly varying the inphase and quadrature responses.The averaged stochastic equations are exactly solved by the method of moments for the mean square response amplitude for the case of zero offset.A perturbation-based moment closure scheme is proposed for the case of nonzero offset.The effects of damping,detuning,and bandwidth and magnitudes of the random excitations are analyzed.The theoretical analyses are verified by the numerical results.The theoretical analyses and numerical simulations show that the peak amplitudes can be strongly reduced at the large detunings.

ON THE HOMOCLINIC ORBITS IN A CLASS OF TWO-DEGREE-OF-FREEDOM SYSTEMS UNDER THE RESONANCE CONDITIONS

A class of two-degree-of-freedom systems in resonance with an external, parametric excitation is investigated, the existence of the periodic solutions locked to Omega is proved by the use of the method of multiple scales. This systems can be transformed into the systems of Wiggins under some conditions. A calculating formula which determines the existence of homoclinic orbits of the systems is given.

Study on Relation between Dynamic Imbalance Degree and Product of Inertia

Based on the study of the relation between the dynamic imbalance degree and the product of inertia,a new static test method of the dynamic imbalance degree is presented.It is theoretically proved that the essence of the imbalance degree test for projectile body is the test of its product of inertia.A more precise calculation formula of dynamic imbalance degree is also given.The experiment results show that this method can not only reduce the cost of equipment,simplify the test procedures,save human resource,but also has more reliable test precision.

区域水平衡及失衡程度度量方法

区域水平衡量化及诊断是水网工程建设优化和水资源均衡调控的基础,对提升水安全保障能力、支撑经济社会稳定发展、实现人水和谐具有重要意义。本文从空间、时间、结构、过程、总量五个维度解构了区域人水系统的四大平衡,即反映水收入项和支出项定量关系的水收支平衡、体现经济社会供水量与需水量匹配关系的经济社会供需水平衡、结合经济社会-生态系统发展与用水定量关系的经济社会与生态用水平衡、表征人水系统发展状态的人水关系和谐平衡,并提出相应的水平衡度量方法。多角度解析了区域水平衡的失衡状态,提出四大平衡的失衡程度度量方法及区域水平衡的失衡程度综合度量方法。以沁河流域为实例应用和检验了上述方法,结果表明:提出的度量方法具有科学性和适用性,能够应用于区域水平衡研究实践;2019年沁河流域水平衡的失衡度为0.327,处于蓄水量减少、水资源短缺、生态端亏水、水系统受损的中度失衡状态,后续应注重人类涉水行为的管控。研究成果可为区域水平衡评估与调控提供理论支撑,服务国家或区域水平衡策略制定和水网工程规划。

基于德尔菲法构建护理专业学位研究生与肿瘤专科护士核心能力联合培养方案

目的:构建护理专业学位研究生与肿瘤专科护士核心能力联合培养方案,为推动我国护理专业学位研究生教育的发展提供参考。方法:通过文献分析法及半结构化访谈初步形成护理专业学位研究生与肿瘤专科护士核心能力联合培养方案条目池,制定专家函询问卷,并采取德尔菲专家函询法对15名专家进行专家函询,最终形成护理专业学位研究生与肿瘤专科护士核心能力联合培养方案。结果:3轮函询专家积极性系数均为100.0%,专家权威系数分别为0.838,0.880和0.880。经过咨询最终形成包括理论知识掌握能力、临床综合实践应用能力、组织管理能力、教学及科研能力、发展能力5个一级指标、17个二级指标、96个三级指标的护理专业学位研究生与肿瘤专科护士核心能力联合培养方案。结论:构建的护理专业学位研究生与肿瘤专科护士核心能力联合培养方案具有良好的可靠性与科学性,对肿瘤护理方向专科人才培养提供参考。

CVBEM and FVM Computational Model Comparison for Solving Ideal Fluid Flow in a 90-Degree Bend

While finite volume methodologies (FVM) have predominated in fluid flow computations, many flow problems, including groundwater models, would benefit from the use of boundary methods, such as the Complex Variable Boundary Element Method (CVBEM). However, to date, there has been no reporting of a comparison of computational results between the FVM and the CVBEM in the assessment of flow field characteristics. In this work, the CVBEM is used to develop a flow field vector outcome of ideal fluid flow in a 90-degree bend which is then compared to the computational results from a finite volume model of the same situation. The focus of the modelling comparison in the current work is flow field trajectory vectors of the fluid flow, with respect to vector magnitude and direction. Such a comparison is necessary to validate the development of flow field vectors from the CVBEM and is of interest to many engineering flow problems, specifically groundwater modelling. Comparison of the CVBEM and FVM flow field trajectory vectors for the target problem of ideal flow in a 90-degree bend shows good agreement between the considered methodologies.

专业学位研究生教育的数字化转型:动因、定位和变革路径

专业学位研究生教育以实践为导向,目标是培养某一职业领域中能创造性地从事实际工作的高层次复合型应用人才。数字技术的迅猛发展与创新给予了专业学位研究生教育新的动能,提供了新的机遇。数字技术的赋能、内生发展需求的赋能、国家政策的加持等推动专业学位研究生教育数字化转型。数字化转型中的专业学位研究教育目标要从对人才的认知、思维,人才的知识转化、实践能力,专业学位研究生教育生态等方面进行准确定位。实现专业学位研究生数字化转型,要推进教学方式变革,加强数字化课程建设,提升教师队伍数字化素养,创新产教融合机制。

生态农业培训效果的耦合协调度研究

为未来生态农业培训模式设计和创新实践提供理论和现实依据,进而为农业高质量发展提供政策启示,基于2012—2021年我国31个省(市、自治区)的相关统计数据,分析政策支持、市场竞争、环保意识、培训资源四个要素之间的耦合协调关系。运用耦合协调度模型,构建影响生态农业培训效果要素系统的协同度评价模型,分析政策支持、市场竞争、环保意识、培训资源四个要素之间耦合协调的时空演变特征。在此基础上,通过障碍度模型识别出制约生态农业培训效果的关键因素,探究我国生态农业培训效果影响要素耦合协调的变化趋势与制约因素。研究发现:2012—2021年全国31个省(市、自治区)四要素耦合协调度整体表现为上升趋势,由0.478增至0.565,增幅为36.61%,但耦合协调度相对较低;在空间分布方面,各省(市、自治区)四要素耦合协调度呈现显著正相关;各要素障碍度由大到小依次为:市场竞争、培训资源、政策支持、环保意识,影响各要素耦合协调的主要障碍因子为政策支持中的政府补助金额,市场竞争中的涉农院校数量,环保意识中的有机肥的投入量,培训资源中的培训场地面积。

断裂破坏区域性泥岩盖层程度研究方法的改进

为了更加准确地研究断裂破坏区域性泥岩盖层程度,基于断裂破坏区域性泥岩盖层机理及程度的影响因素,通过断层岩和区域性泥岩盖层压实成岩程度代替其排替压力,改进了断裂破坏区域性泥岩盖层程度的研究方法,并将改进前后方法分别应用于研究海拉尔盆地贝尔凹陷呼和诺仁构造F1断裂破坏大一下段区域性泥岩盖层程度。结果表明:改进前后方法研究均得到测点9处F1断裂破坏大一下段区域性泥岩盖层程度最大,测点13处最小,其余测点介于二者之间,在测点1~8和12~15处有利于南一段源岩生成油气在大一下段区域性泥岩盖层之下南二段聚集与保存,但测点1~6无油气发现,是由于其构造位置低,油气供给不足,未充满所致,与目前F1断裂处南二段已发现油气分布相吻合。改进前方法研究成果虽与改进后方法研究成果具有相同的变化规律,但其值相对较大,低估了F1断裂破坏大一下段区域性泥岩盖层程度,表明改进后方法研究结果可能更符合地下实际,而且方便易行。