Free boundary and optimal stopping problems for American Asian options

We give a complete and self-contained proof of the existence of a strong solution to the free boundary and optimal stopping problems for pricing American path-dependent options. The framework is sufficiently general to include geometric Asian options with nonconstant volatility and recent path-dependent volatility models.      

Human resource management in Chinese multinationals in the United Kingdom: The interplay of institutions,culture, and strategic choice

This is a study of the challenges faced by Chinese expatriate managers and their strategic responses in securing a workable degree of alignment in UK subsidiaries, against a backdrop of competing home‐country and host‐country pressures. Although much of the literature on home‐country and host‐country effects tends to either adopt a culture or an institutional approach, this study highlights the intermeshed nature of the two. In locating cultural dynamics within an institutional firmament, this study juxtaposes the effects of each and draws conclusions as to their intersection. It is founded on in‐depth interviews with home‐country and host‐country managers. The findings suggest, on the one hand, Chinese expatriate managers tended to see local regulations as an obstacle to efficiency, rather than as a means to access context‐specific complementarities. On the other hand, these managers recognized the need to fit in with established locally specific ways of doing things and in securing sufficient staff buy in to sustain operations, and played a key intermediary role between headquarters and subsidiary.     

混凝土水分传输及边界条件试验研究

混凝土内部水分传输是导致耐久性问题的主要原因。根据混凝土块体和薄片在水分传输方面的相似性,基于已有混凝土润湿过程水分传输模型推导了混凝土薄片中水分传输方程,研究了纯水和不同浓度盐溶液环境下混凝土润湿过程水分传输规律,并以混凝土薄片为对象模拟研究了混凝土边界层水分传输规律。研究结果表明:混凝土边界层润湿过程由毛细吸附为主导,离子的存在不改变基本规律,仅影响传输速率。通过试验数据对质量传输模型进行拟合和验证,结果表明二者相关性较好。并在此基础上推导出了混凝土边界层饱和度变化模型,较好地描述了一维传输方向上混凝土边界层的饱和度变化规律。     

数值波流水池构造方法研究

该文在FLUENT软件平台下构造了二维数值波流水池.基于不可压缩流体RANS方程建立数学模型,使用VOF方法追踪自由面位置;将水池入口取为波浪与水流相遇并产生相互作用的起始位置,给定入射静水波和水流叠加的边界条件;在水池下游设置消波区,采用动量源项消波方法对波浪进行衰减,消除波浪在水池出口边界处的反射,生成了波浪和水流共存的稳定流场.针对不同水流流速剖面和波浪条件进行了数值模拟,并通过实验数据考核数值水池模型的准确性.对Thomas的实验数据进行数值仿真,得到了不同流速的均匀逆流对波高和波长的影响;针对剪切流,模拟了Kemp等的实验数据,计算不同波幅的波浪在非均匀顺流和逆流中的变形.结果显示,数值结果与实验数据吻合良好,表明了该数值波流水池模型能够较为准确地模拟波浪和定常水流的相互作用.     

基于改进结合界面边界条件方法的矩形柱驰振数值模拟

针对流固耦合问题该文提出了一种改进结合界面边界条件方法,即通过重构界面修正公式,完全消除未经修正的拖曳力,引入新的耦合参数ω/△t以考虑时间步的影响.基于任意拉格朗日-欧拉有限元方法和弱耦合算法求解流固耦合系统.采用CBS(Characteristic-Based Split)稳定化流体有限元算法求解不可压缩Navier-Stokes方程;采用Newmark-β法求解结构运动方程;对流固耦合系统的网格更新,采用子块移动技术结合正交-半扭转弹簧近似法;在流场压力泊松方程中加入质量源项以保证几何守恒律;增加界面处的位移修正,以保持几何连续性.并运用该方法数值模拟了低雷诺数下长宽比4:1的矩形柱驰振,计算结果与已有文献结果高度吻合.     

The effect of variable viscosity on the flow and heat transfer of a viscous Agwater and Cu-water nanofluids

A numerical study is carried out to study the effects of the temperature dependent viscosity on the flow and heat transfer of a nanofluid over a flat surface in the presence of viscous dissipation. The governing nonlinear partial differential equations are transformed into nonlinear ordinary differential equations, and are solved numerically by the Keller-box method. The numerical results indicate that the effect of nanoparticle volume fraction is to increase the heat transfer and hence enhance the thermal boundary layer thickness. This is true even in the presence of variable viscosity and the viscous dissipation. Furthermore, the results obtained for heat transfer characteristics with nanoparticles reveal many interesting behaviors that warrant further study on the effects of the "nano-solid-particles".     

Experimental hydrodynamic study of the Qiantang River tidal bore

To study the hydrodynamics of tidal bore, a physical modeling study is carried out in a rectangular flume with considerations of the tidal bore heights, the propagation speeds, the tidal current velocities, the front steepness, and the bore shapes. After the validation with the field observations, the experimental results are analyzed, and it is shown that: (1) the greater initial ebb velocity or the larger initial water depth impedes the tidal bore propagation, (2) the maximum bore height appears at an initial ebb velocity in the range of 0.5 m/s-1.5 m/s, (3) when the Froude number exceeds 1.2, an undular bore appears, after it exceeds 1.3, a breaking bore occurs, and after it exceeds 1.7, the bore is broken.     

Exploring necessary conditions in HRM research: Fundamental issues and methodological implications

Although the notion that HRM activities are necessary conditions for achieving certain outcomes is widespread in HRM research, most empirical studies follow an additive sufficiency logic. That is, they analyse whether HRM activities increase an outcome, assuming that they can compensate for one another. However, this does not correspond to the idea of necessity where single HRM activities are required for an outcome to occur and cannot be compensated when absent. We discuss the differences between sufficiency and necessity logics in terms of theory, methodology, and practical relevance. Also, we suggest using a new approach and analysis technique in HRM research: necessary condition analysis. We illustrate the application of the method by analysing data on the relationship between ability‐, motivation‐, and opportunity‐enhancing HRM practices (i.e., high‐performance work practices) and employee performance. This illustrative example highlights that necessary conditions require particular theoretical attention and suitable empirical methods. The paper concludes by showing the value of studying necessary conditions, because such analyses allow straightforward recommendations to be given of high relevance for HRM practice, which differ from and add to recommendations based on additive sufficiency logic and analyses.     

Performance assessment of airlines using range-adjusted measure,strong complementary slackness condition,and discriminant analysis

This study integrates RAM (range-adjusted measure), SCSC (strong complementary slackness condition), and DEA–DA (data envelopment analysis–discriminant analysis) to rank airlines. As conventional DEA models do not fully use all inputs and outputs, they result zero in many multipliers. These sorts of DEA models may yield many efficient decision-making units (DMUs). This decreases the discrimination power of DEA. To overcome this limitation, this study proposes a novel application of RAM–DEA/SCSC along with DA. A case study demonstrates the applicability of our proposed approach.     

在整体结构关系中把握文本的意义--以杜甫《登高》的重新解读为例

《登高》表现的两类意象是由诗的内部结构决定的，即表现生存状态中的生命感受。这种结构关系正是由诗人的情感结构决定的。诗人“登高”时感受到的，就是他一生坎坷、风烛残年生存状态中的一种飘零感、孤独感、凄凉感、无所归依感，甚至是绝望感。而把这两种感受转化成诗的意象表现出来，就自然成了两种意象，而两种意象之间自然也就构成了一种因果性的内在结构关系。从生存状态和生命感受的因果关系中解释《登高》的意象意义，既可以在整体结构中解释每一联诗句的意义，又可以在结构关系中解释每一个意象的意义。这种结构、关系、整体的解释就超越了那种一句一句累加式的解释。