Relationship between knowledge sharing and performance: A survey in Xi’an,China

This paper explores the quantitative relationship between knowledge sharing and performance, with contextual factors in consideration. First, we argue that both knowledge sharing and its contextual factors should be associated with performance. Then, we analyze the multi-dimensional characteristics of knowledge sharing and propose six measures for it. Next, we model the relationship between knowledge sharing and performance, integrating various contingent factors with the model framework, some of which have significant influences on the relationship between knowledge sharing and performance. After that, we propose four alternative models and corresponding propositions for knowledge sharing-contingent variables relationship, and present a quantitative formulation of the relationship between knowledge sharing and performance. Finally, we conduct a survey of 249 organizations in Xi’an, China, and show the empirical results. Our propositions about the knowledge sharing-performance relationship and contingent factors are supported by the survey. The empirical results suggest that managers have to pay attention to some contingent factors while they commit to knowledge sharing. This study adds to the understanding of the effects of knowledge sharing on performance, and gives implications to the practice of knowledge sharing.     

Wet concrete loading of profiled trough girders

Profiled trough girders act as the permanent formwork for reinforced concrete beams, and form a member known as a composite profiled beam. During the construction phase, the pouring of wet concrete may influence the strength and stiffness of the profiled girder. The method of profiled composite construction is thus described herein and the influence of the wet concrete loading of profiled trough girders is studied. A series of three profiled trough girders were tested under wet concrete loads, and their deformations were monitored. A folded plate finite element method is then developed to model the in-plane and out-of-plane deformations that the trough wall is subjected to during this wet concrete loading.     

Fluid flow and heat transfer in an optical fiber coating process

The optical fiber coating process, using a die and applicator system, was numerically simulated. The coupled partial differential equations, governing the fluid flow and heat transfer, were solved on a transformed, non-uniform, staggered grid. A finite volume method, with conjugate heat transfer, boundary-fitted grid, and variable transport properties, was employed. The pressure was calculated using a SIMPLE-based algorithm. An isothermal case was first modeled, where the effect of the Reynolds number (Re) was studied for different geometries. Different coating fluids were considered. A conjugate boundary condition was employed at the fiber–fluid interface for the non-isothermal flow. A free surface boundary condition was used at the fiber entry into the coating fluid. The meniscus was prescribed on the basis of prior experimental work. Regardless of fiber speed, a circulating flow was observed in the applicator. High shear rates at the dynamic contact point suggest that air can be entrained with a fast moving fiber. It was also found that pressures at the coating fluid inlet did not play a major role, for typical fiber speeds, whereas the thermal conditions that affect the properties of the fluid, such as viscosity, made a significant impact on both the flow and the thermal field. This work could be used to determine the parameters that are critical for improving the quality of the coating, particularly its uniformity, and the production rate.     

Effects of tensile reinforcement ratio and compressive strength on the behaviour of over-reinforced helically confined HSC beams

The technology of high strength concrete has improved over the last decade. High strength concrete (HSC) is more brittle than normal strength concrete. The brittleness increases with the use of over-reinforced section, which fails suddenly without warning. Use of over reinforced sections is restricted in codes of practice of concrete design. This paper presents an experimental study of the behaviour of five HSC beams confined with helical reinforcement. Concrete compressive strength in the range 72–95 MPa and tensile reinforcement ratio in the range 5.24–7.86% were used. The main results indicate that as the concrete compressive strength increases the displacement ductility index decreases and the load at spalling-off the concrete cover increases. Also, the displacement ductility index increases as the longitudinal reinforcement ratio increases and the load at spalling-off the concrete cover decreases.     

影响ETM影像土地利用/覆盖分类精度因素的研究

训练样本量、辅助数据和分类法是影响土地利用/覆盖分类精度的3个主要因素,通过找到这3个因素的最佳组合方式以提高分类精度,分别在25%、50%、75%、100%样本量下,加入NDVI、DEM和纹理均值特征作为辅助数据,比较了分类回归树、支持向量机、最大似然法3种分类法的效果,探讨了训练样本、辅助数据以及分类技术对土地利用/覆盖分类精度的影响。结果表明：支持向量机总体分类精度较高,在相同样本量和没有有效辅助数据的情况下,SVM可以获得最佳的分类结果,总体分类精度在85%以上;在进行分类时,加入NDVI和纹理均值特征使分类回归树分类精度提高了2.82%,说明该方法对有效辅助数据的加入较为敏感;在获取的训练样本集有限而可获取有效的辅助数据时,应优先考虑利用分类回归树进行土地利用/覆盖分类。     

100 t伸缩臂履带式起重机臂架结构设计和优化分析

为确保100 t伸缩臂履带式起重机臂架结构设计的合理性,采用壳单元建立该起重机的有限元模型,用ANSYS计算臂架结构应力和应变,得到臂架的应力和应变分布,验证臂架的强度和稳定性.在起重机性能满足要求的情况下,以减轻结构自重为优化目标,以截面尺寸为优化设计变量,用ANSYS对臂架进行优化设计.优化设计后的臂架满足设计规范,臂架截面尺寸缩小、自重降低,整机性能得到提高.     

用于智能组卷的自适应小生境复合遗传算法

传统遗传算法的选择策略缺乏多样性保护机制,易出现早熟收敛。为解决智能组卷问题,采取小生境技术完成遗传操作中的种群进化机制。利用个体浓度的大小,设置自适应变异算子,保证种群多样性,防止种群陷入局部收敛;增加阈值以保证算法在接近最优解时回归到自适应遗传算法,简化算法计算量,加快算法的收敛速度。本文提出一种自适应与小生境技术复合遗传算法,来均衡算法的全局搜索和局部快速开发能力。最后,实例验证了所提算法的有效性。