粗糙表面电磁散射系数数字方法分析与比较

回顾了随机粗糙表面电磁散射特性计算方法的特点,分析对比了各类积分方程法和微分方程法的核心算法,着重讨论了矩阵分裂算法的计算效率,以及时域有限差分法求解色散粗糙面宽带散射特性的有关问题,指出了粗糙表面散射系数的计算和选择方法。     

输电钢管杆稳定性分析的阶梯折算法

应用一维非均质体结构的阶梯折算法理论,建立了输电钢管杆的数值分析模型,推导了钢管杆的整体稳定计算方法,算法运用计算机易于实现,解决了荷载和刚度沿杆体变化的复杂杆结构整体稳定二阶计算问题,在电网工程建设和设计中有较好的实用价值。     

未确知数减法运算的推广

本文是文献[1]定义的未确知数减法运算的推广,且给出了一个新的定义方式.     

整合技术概念及对新古典就业理论的反思

笔者提出整合技术概念，即所有的工人整合在一起操作生产系统；如果任何一名工人缺失，则生产系统不能运行。如果一种技术严格具有整合技术的性质，那么在到达能使生产系统运行之前，工人的边际产品为零。如果增加一名工人生产系统就可运行，则这名工人的边际产品等于总产品。如果再增加一名工人的边际产品为零，则边际产品曲线退化为一条垂直线。新古典边际劳动生产率理论认为，厂商雇闸工人的工资等于劳动的边际产品，但这一理论显然不适合整合技术。因此，要研究在更一般条件下厂商雇用决策的机制。采用整合技术的概念可以对很多经济学的理论问题进行重新思考。     

Nonparametric estimators of the bivariate survival function under random censoring

A large number of proposals for estimating the bivariate survival function under random censoring have been made. In this paper we discuss the most prominent estimators, where prominent is meant in the sense that they are best for practical use; Dabrowska's estimator, the Prentice–Cai estimator, Pruitt's modified EM-estimator, and the reduced data NPMLE of van der Laan. We show how these estimators are computed and present their intuitive background. The asymptotic results are summarized. Furthermore, we give a summary of the practical performance of the estimators under different levels of dependence and censoring based on extensive simulation results. This leads also to a practical advise.     

The Russian option: Finite horizon

We show that the optimal stopping boundary for the Russian option with finite horizon can be characterized as the unique solution of a nonlinear integral equation arising from the early exercise premium representation (an explicit formula for the arbitrage-free price in terms of the optimal stopping boundary having a clear economic interpretation). The results obtained stand in a complete parallel with the best known results on the American put option with finite horizon. The key argument in the proof relies upon a local time-space formula.Received: March 2004, Mathematics Subject Classification (2000): 91B28, 35R35, 45G10, 60G40, 60J60JEL Classification: G13Goran Peskir: Centre for Analytical Finance (funded by the Danish Social Science Research Council) and Network in Mathematical Physics and Stochastics (funded by the Danish National Research Foundation).The first draft of the present paper has been completed in September 2002. I am indebted to Albert Shiryaev for useful comments.     

Non‐additivity in Accounting Valuation: Theory and Applications

This paper has three objectives. First, to introduce a theoretical solution to the issue of non‐additivity between assets in place, relying on an accounting‐based valuation approach. Second, to explain how such an approach can be implemented empirically by measuring synergies between assets. Third, to present the properties of this non‐additive valuation technique. We use Choquet capacities, that is, non‐additive aggregation operators, to measure the interactions between assets and apply our methodology to a sample of US firms from the capital goods industry. To operationalize our approach we examine the relationships between synergies—captured by Choquet capacities—and the market‐to‐book ratio (proxying for growth options), and show how interactions between assets are consistently linked to a firm’s market‐to‐book ratio. We also measure firm‐specific productive efficiency relative to the industry and firm size. For large firms, efficiency, as defined by our approach, is positively associated with higher future operating cash flows. For small firms, efficiency is positively associated with higher future sales growth. We document that the non‐additive approach appears to be better able to identify expected relationships between efficiency and future performance than a simpler approach based on the market‐to‐book ratio.     

闸墩门槽二期整体式滑模施工技术

长洲水利枢纽外江泄水闸工程是整个外江工程关键性工期的保证工程,由于遭遇2006年洪水,外江工程进度严重滞后,需要对原施工方案进行优化。整体式滑模施工技术具有施工进度快,保证二期混凝土施工质量,克服了常规单边门槽滑模的缺点等优势,据此,文章阐述了整体式滑模施工的技术要点。     

The impact of a firm's make, pseudo-make, or buy strategy on product performance

The bulk of the product architecture and make-buy choice literature deals with product architecture changes from integral to modular form. This development is often associated with a firm's tendency to change from a make to a buy strategy. However, a few studies investigate the change of product architecture in the reverse direction - from modular to integral form - and the subsequent change in the firm sourcing decision from a buy to a make strategy. These studies hold to the presumption that a firm following a make strategy will outperform firms following a buy strategy in dealing with integral product architectures. Based on the knowledge-based view, we argue for the viability of a sourcing strategy between the pure make and buy strategies - a pseudo-make strategy. We also argue that as product architecture changes from a modular to integral form, firms adopting this pseudo-make strategy are likely to show better product performance than firms following a pure make or buy strategy due to the relative knowledge advantages of the pseudo-make strategy in dealing with the integral product architecture. We examine the impact of the make/pseudo-make/buy strategies on product performance in the U.S. bicycle derailleur and freewheel market from 1980 to 1992 and provide theoretical and managerial implications of our results. Our findings highlight an important distinction between the pseudo-make and make-buy strategies that has not previously been fully appreciated in the extant literature, and as a result increases our understanding of why some firms do not switch strategies from a buy to a make strategy when product architecture changes from modular to integral form as previously expected.     

MULTIFRACTIONAL STOCHASTIC VOLATILITY MODELS

The aim of this work is to advocate the use of multifractional Brownian motion (mBm) as a relevant model in financial mathematics. mBm is an extension of fractional Brownian motion where the Hurst parameter is allowed to vary in time. This enables the possibility to accommodate for varying local regularity, and to decouple it from long‐range dependence properties. While we believe that mBm is potentially useful in a variety of applications in finance, we focus here on a multifractional stochastic volatility Hull & White model that is an extension of the model studied in Comte and Renault. Using the stochastic calculus with respect to mBm developed in Lebovits and Lévy Véhel, we solve the corresponding stochastic differential equations. Since the solutions are of course not explicit, we take advantage of recently developed numerical techniques, namely functional quantization‐based cubature methods, to get accurate approximations. This allows us to test the behavior of our model (as well as the one in Comte and Renault) with respect to its parameters, and in particular its ability to explain some features of the implied volatility surface. An advantage of our model is that it is able both to fit smiles at different maturities, and to take volatility persistence into account in a more precise way than Comte and Renault.