技术溢出情况下企业创新模式选择的非对称博弈模型研究

讨论了技术溢出情况下的企业创新模式选择问题,对于企业处理技术专有性与溢出性的矛盾具有理论指导意义。在AJ模型的基础上,把产品替代率变量引入需求函数中,分析了两个企业在初始单位成本不同时,技术溢出对它们创新模式选择的影响。通过研究发现,企业间产品替代率越大、技术溢出临界值越大,则企业合作创新的空间越小。

拉萨宗角禄康公园健身空间满意度的非线性分析

研究针对拉萨市宗角禄康公园健身空间的满意度进行调查,梯度提升决策树分析结果表明:影响拉萨健身空间满意度的因子与内地存在差异性,其中绿化环境、宗教活动、健身器材设施是对满意度影响较大的因素。结合奖惩对比法和影响非对称分析法,探讨了相关属性对健身空间的非线性影响,研究发现餐饮服务设施、健身器材设施、无障碍设施、遮阳避雨设施是需要优先改进的,在资源允许的情况下,绿化环境、休息设施是可以进一步优化的。

比特币交易网络结构演化特征与比特币价格波动的非对称联动研究

作为当前最具影响力的数字加密货币,比特币的价格机制一直是世界各国学者们关注的焦点。本文基于异构网络分析理论,利用2015年1月1日—2018年7月31日共计1307天的比特币交易数据构建比特币交易网络,并采用序列相关分析、长期协整检验、线性回归和门限回归模型分析比特币交易网络结构演化特征与比特币价格的联动机制。研究发现:比特币交易网络中的交易节点数、地址节点数、地址节点平均余额、地址网络直径对比特币价格具有正向联动效应,网络密度对比特币价格具有负向联动效应。当比特币价格处于低于和高于4360美元两种不同情况时,网络结构演化特征对价格的联动影响具有显著的非对称性,并且当价格高于4360美元时,网络结构演化特征对价格的影响更加显著。

韧性理念下旧工业区更新改造优先级研究

在盘活存量用地和可持续发展理念不断推进的背景下,根据疫情常态下对于城市韧性提升的新要求,旧工业区(Old Industrial Zone,OIZ)更新改造项目如何发挥自身能动性,增强自身应对外界伤害的能力,并为城市在面对突发事件时提供应急响应空间是当下亟待解决的关键问题。研究在广泛查阅文献、实地调研项目以及参考相关标准的基础上,构建了旧工业区使用者满意度的基本属性,选取北京、西安和深圳典型旧工业区更新改造项目进行满意度调研,运用非对称影响绩效分析法(Asymmetric Impact-Performance Analysis,AIPA)量化旧工业区属性绩效与使用者满意度之间的非对称关系,将属性维度定位在AIPA矩阵的4个象限,讨论了为提升满意度应采取的属性绩效管理优先级顺序。结果显示:旧工业区属性可分为既有建筑、生态环境、社会韧性和政策韧性4个维度。综合考虑属性绩效水平,对改造内容进行优先级排序,并提出各属性的提升策略,最大限度提高使用者对改造项目的满意度。同时,以期为政策制定者、规划者和设计人员提供合理有效的参考借鉴,为旧工业区使用者提供一个稳健的、具备抵御风险能力的空间环境,为同类型的更新改造项目提供科学适用的参考依据。

利率市场化进程中城商行利率风险度量及应对——以浙江省为例

城商行的资产负债配置在利率对称调整的情况下具有一定的抗风险能力,但在利率非对称调整条件下,其净利息收入将受到重大冲击。新兴金融业务应成为城商行的转型着力点,可选择适合的业务发展方式和经营模式,并借助地方政府的支持。加强对存贷款定价机制的研究,采用总行集中的模式构建内部资金转移定价体系,为内部资金的合理定价和有效资产配置奠定基础。发挥城商行服务中小企业的优势,走差异化的特色发展道路。提高利率风险管理意识,投入研发银行账户利率风险管理系统,建立完善的账户利率风险管理机制,合理预测利率变化,提前安排自身的资产负债结构,有效规避风险,并运用多种利率衍生工具规避利率风险。

目的地属性绩效对游客总体满意度的非对称影响——以北京为例

目的地属性绩效与游客总体满意度间的关系并非总是线性和对称的。本文依托北京入境游客问卷调查数据,利用奖惩对比分析和非对称影响绩效分析方法,检验了目的地属性绩效对游客总体满意度的非对称影响效应。结果显示:(1)城市目的地属性可划分为旅游信息、旅游交通、自然环境、娱乐活动、核心吸引物、休闲氛围、旅游安全、服务设施和通信服务共9个维度;(2)目的地属性绩效对游客总体满意度的影响存在非对称效应,核心吸引物、旅游交通、旅游安全和服务设施对游客总体满意度具有负向非对称影响,娱乐活动与旅游信息则具有正向非对称影响,仅休闲氛围对游客总体满意度的影响基本呈对称性;(3)城市目的地游客总体满意度的提升,应优先提高休闲氛围属性的绩效,其次是改善服务与设施,再进一步是改进娱乐活动与旅游信息。

乡村振兴战略实施背景下返乡农民工林业高创业绩效路径研究

随着集体林权制度改革的不断深入,引发了林业领域的创业活动。农民工返乡开展集体林业创业作为乡村振兴战略实现的重要依托,是促进乡村产业兴旺的内生性动力、提高创业绩效是激励农民工返乡创业的有效途径,因此探究对农民工创业者实现高创业绩效产生影响的组态路径具有重要意义。文章将“农民工自身和外部环境作用于创业绩效的构型”作为核心研究问题,从归因理论和因果复杂性的视角,以模糊集定性比较分析为研究方法,对江苏省13个市收集的223份返乡创业农民工问卷进行系统分析,得出了5条高创业绩效构型。结果表明:(1)农民工返乡高创业绩效的取得是多因素共同作用的结果,且存在多条实现路径。(2)不同性别的农民工返乡创业过程中,实现高创业绩效的路径组态并不相同且导致不同性别取得高创业绩效的核心条件存在差异。(3)职业培训与专业技能之间存在替代关系,代际创业与政府补贴、职业培训也存在替代关系,代际创业与家庭情感支持、政府补贴、职业培训间均呈现互补关系。基于上述研究结果,文章提出政策启示:(1)要进一步加大对返乡农民工林业创业的支持力度。(2)要进一步加强返乡农民工职业技能培训和创业培训。(3)要通过政府支持和家庭关怀提高女性创业者高创业绩效。

Learning compact binary code based on multiple heterogeneous features

A novel hashing method based on multiple heterogeneous features is proposed to improve the accuracy of the image retrieval system. First, it leverages the imbalanced distribution of the similar and dissimilar samples in the feature space to boost the performance of each weak classifier in the asymmetric boosting framework. Then, the weak classifier based on a novel linear discriminate analysis （LDA） algorithm which is learned from the subspace of heterogeneous features is integrated into the framework. Finally, the proposed method deals with each bit of the code sequentially, which utilizes the samples misclassified in each round in order to learn compact and balanced code. The heterogeneous information from different modalities can be effectively complementary to each other, which leads to much higher performance. The experimental results based on the two public benchmarks demonstrate that this method is superior to many of the state- of-the-art methods. In conclusion, the performance of the retrieval system can be improved with the help of multiple heterogeneous features and the compact hash codes which can be learned by the imbalanced learning method.

DIFFERENTIAL QUADRATURE FOR AXISYMMETRIC GEOMETRICALLY NONLINEAR ANALYSIS OF CIRCULAR PLATES

New developments have been made on the applications of the differential quadrature(DQ)method to analysis of structural problems recently.The method is used to obtain solutions of large deflections, membrane and bending stresses of circular plates with movable and immovable edges under uniform pressures or a central point load.The shortcomings existing in the earlier analysis by the DQ method have been overcome by a new approach in applying the boundary conditions. The accuracy and the efficiency of the newly developed method for solving nonlinear problems are demonstrated.

Conserved quantities from Lie symmetries for nonholonomic systems

This paper presents a new method to seek the conserved quantity from a Lie symmetry without using either Lagrangians or Hamiltonians for nonholonomic systems. The differential equations of motion of the systems are established. The definition of the Lie symmetrical transformations of the systems is given, which only depends upon the infinitesimal transformations of groups for the generalized coordinates. The conserved quantity is directly constructed in terms of the Lie symmetry of the systems. The condition under which the Lie symmetry can lead to the conserved quantity and the form of the conserved quantity are obtained. Finally, an example is given to illustrate the application of the result.

Resistance Analysis of Unsymmetrical Trimaran Model with Outboard Sidehulls Configuration

The application of multi-hull ship or trimaran vessel as a mode of transports in both river and sea environments have grown rapidly in recent years.Trimaran vessels are currently of interest for many new high speed ship projects due to the high levels of hydrodynamic efficiency that can be achieved,compared to the mono-hull and catamaran hull forms.The purpose of this study is to identify the possible effects of using an unsymmetrical trimaran ship model with configuration（S/L） 0.1-0.3 and R/L=0.1-0.2.Unsymmetrical trimaran ship model with main dimensions： L=2000mm,B=200 mm and T=45 mm.Experimental methods（towing tank） were performed in the study using speed variations at Froude number 0.1-0.6.The ship model was pulled by an electric motor whose speed could be varied and adjusted.The ship model resistance was measured precisely by using a load cell transducer.The comparison of ship resistance for each configuration with mono-hull was shown on the graph as a function of the total resistance coefficient and Froude number.The test results found that the effective drag reduction could be achieved up to 17% at Fr=0.35 with configuration S/L=0.1.

Symmetry Analysis of Nonlinear Incompressible Non-Hydrostatic Boussinesq Equations

The symmetries of the （2＋1）-dimensional nonlinear incompressible non-hydrostatic Boussinesq （INHB） equations, which describe the atmospheric gravity waves （GWs）, are researched in this paper. The Lie symmetries and the corresponding reductions are obtained by means of classical Lie group approach. Calculation shows the INHB equations are invariant under some Galilean transformations, scaling transformations, and space-time translations. The symmetry reduction equations and similar solutions of the INHB equations are proposed.

Statistical Properties of Multispecies Competition Ecosystems Subjected to Dichotomous Noises

We investigate statistical properties of multispecies competition ecosystems subjected to both symmetric and asymmetric dichotomous noises. The expression of the stationary probability distribution function （SPDF） is analytically derived by means of mean-field approximation, and verified by stochastic simulations. The results indicate that： （i） A noise amplitude （a0）, a noise autocorrelation time （τ0） and a noise symmetry parameter （k） all can affect the SPDF; （ii） There is an optimal τ0, which makes the mean value of population density be maximal, near which a transition takes place, i.e., the stationary mean value of species density （（x）st） suddenly falls to a lower constant, （iii） As k decreases, the maximum of （x）xt and the optimal 70 increase. The parameter planes of TO -- a20 and τ0- k for the transition are plotted.

Three-dimensional consolidation deformation analysis of porous layered soft soils considering asymmetric effects

Long-term settlements for underground structures, such as tunnels and pipelines, are generally observed after the completion of construction in soft clay. The soil consolidation characteristic has great influences on the long-term deformation for underground structures. A three-dimensional consolidation analysis method under the asymmetric loads is developed for porous layered soil based on Biot's classical theory. Time-displacement effects can be fully considered in this work and the analytical solutions are obtained by the state space approach in the Cartesian coordinate. The Laplace and double Fourier integral transform are applied to the state variables in order to reduce the partial differential equations into algebraic differential equations and easily obtain the state space solution. Starting from the governing equations of saturated porous soil, the basic relationship of state space variables is established between the ground surface and the arbitrary depth in the integral transform domain. Based on the continuity conditions and boundary conditions of the multi-layered pore soil model, the multi-layered pore half-space solutions are obtained by means of the transfer matrix method and the inverse integral transforms. The accuracy of proposed method is demonstrated with existing classical solutions. The results indicate that the porous homogenous soils as well as the porous non-homogenous layered soils can be considered in this proposed method. When the consolidation time factor is 0.01, the value of immediate consolidation settlement coefficient calculated by the weighted homogenous solution is 27.4% bigger than the one calculated by the non-homogeneity solution. When the consolidation time factor is 0.05, the value of excess pore water pressure for the weighted homogenous solution is 27.2% bigger than the one for the non-homogeneity solution. It is shown that the material non-homogeneity has a great influence on the long-term settlements and the dissipation process of excess pore water pressure.

Symmetry Analysis of Two Types of (2+1)-Dimensional Nonlinear Klein-Gorden Equation

By means of the classical symmetry method,we investigate two types of the(2+1)-dimensional nonlinearKlein-Gorden equation.For the wave equation,we give out its symmetry group analysis in detail.For the secondtype of the(2+1)-dimensional nonlinear Klein-Gorden equation,an optimal system of its one-dimensional subalgebrasis constructed and some corresponding two-dimensional symmetry reductions are obtained.

Conductivity of Oxalic Acid in Aqueous Solution at Low Concentration

Oxalic acid is a weak and unsymmetrical bi-basic acid. There exist dissociation and association equilibria among the species in aqueous solution. The molar conductivity of the solution is the sum of the ionic contributions.Based on this idea, a new prediction equation of ionic conductivity was proposed at low concentration. The molar conductivities of the solution and its relevant ions were calculated respectively. The results obtained were in good agreement with those from experiments and the Quint-Viallard equation.

Seismic Assessment of Asymmetric Structures Behaviour by Using Static Non-linear Analysis

The goal of this work is to investigate the seismic behaviour of plan-asymmetric structures by considering the least seismic-resistant directions and the spatial features of the seismic event. New tools for the analysis of the seismic behaviour of plan-asymmetric structures are herein presented and the concepts of ＂Polar Spectrum＂ and limit domains are discussed. In particular, the capacity of the structure is described by using the limit domains based on the Non Linear Static Procedures, while the seismic demand is analysed by introducing a new representation of the spectral response. This representation is based on the construction of a spectral surface obtained by the spectral seismic response for different in-plan directions and the in-plan projection of this surface is herein defined ＂Polar Spectrum＂. The obtained results for two benchmark structures, verified by means of non-linear incremental dynamic analyses, have pointed out that non-linear static analyses, carried out for different in-plan directions of the incoming seismic action, have allowed us to accurately evaluate the least seismic resistant directions.

Symmetry Analysis and Similarity Solutions of a Resonant Davey-Stewartson System

Lie point symmetry analysis is performed to a recently proposed(2+1)-dimensional nonlinear system,theresonant Davey-Stewartson equation.Some similarity solutions of the RDS equation are thus obtained.

Extension of Direct Displacement-Based Design to Plan-Asymmetric RC Frame Buildings

The object of this paper is the evaluation of the seismic response of reinforced concrete frames designed according to the DDBD （direct displacement-based design） approach. The great part of research works about DDBD has been dedicated to planar frames, but recently also some proposals for 3D structures have been presented, in particular for wall structures. This paper will give a further contribution to the extension of the procedure for the case of plan-asymmetric RC （reinforced concrete） frames. The extended methodology is aimed at accounting for the floor rotations on the basis of a given lateral strength distribution along the plan. The procedure was applied to two plan-asymmetric RC frames, characterized by the same geometry but different lateral strength distributions along the plan. The seismic behavior of the designed frames was studied by adopting a fiber model and by performing pushover and nonlinear dynamic analyses.

Structural Synthesis, Dynamic Modeling and Analysis of a 3-DOF Asymmetric Parallel Mechanism

Most research papers about parallel kinematic chainmechanisms investigate symmetric robot manipulators, in which all the limbs connecting the end-effector to the fixed based are composed by the same sequence of links and joints. Contrarily, in some manipulation tasks the velocity and stiffness requirements are anisotropic. In such cases, the asymmetric parallel kinematic chain mechanisms may offer advantages. This work objective is to present the synthesis, dynamic modeling and analysis of a 3-dof asymmetric parallel chain mechanism, conceived as a robot manipulator for pick-and-place operations. Firs＇t, a structural synthesis, resulting in a three translations end-effector, and a kinematic modeling are carried out. Then, the inverse dynamic modeling is developed by employing the virtual work principle. Based on the model equations and on the saturation of the mechanism actuators, a maximum acceleration analysis is performed and shows that although the mechanism has a parallel architecture its actuators influences on the 3-dof are quite decoupled.