750kV输电线路杆塔反击跳闸率分析

对输电线路进行防雷性能的评估是电力设计部门的重要任务。由于当前对雷电波在接地网传播过程中的物理过程还不清晰,因此亟需建立雷击输电线路时杆塔及接地网的准确模型,并计算出该输电线路的雷击跳闸率,从而为防雷性能的设计和评估提供较为准确的判据。所以建立输电线路杆塔和接地网的宽频等效电路对模拟杆塔在雷电冲击作用下的特性具有重要的理论意义和实用价值。提出了一种基于输电线路杆塔和接地体冲击特性的场路耦合建模方法,该方法汲取了黑箱理论建模方法与传统的物理建模方法的优点,避免了其不足。然后将该方法应用于计算多种典型线路杆塔在不同条件下的反击跳闸率,最后选取其中五种主要的影响因素进行了分析。分析的结论可用于指导750kV输电线路具体的塔基接地和施工。     

基于Node.js中间层Web开发的研究与实现——以微信图书借阅平台为例

针对Web研发领域一直面临前后端耦合问题,在充分分析传统的互联网前后端Web软件开发的基础上,提出了引入Node.js作为中间层来解除前、后端之间耦合关系的新解决方案。设计了新的架构模式指导Web软件开发,从而达到提高开发效率、提升代码灵活性、明确开发人员工作职责等目的。基于此研究,真实开发了一个基于微信的图书借阅平台,并以此作为可行性检验的依据,该图书借阅平台使用微信作为前端执行环境,提供图书借阅、图书归还、图书入库、图书浏览功能。系统采用B/S架构,Node.js中间层和后端程序在服务器中运行,用户关注微信公众号后,可以通过微信聊天窗口接收服务器端讯息,也可以通过公众号菜单导航到前端界面,完成图书借阅分享操作,交互方式高效简洁。     

Communication and knowledge as motivators: understanding Singaporean women’s perceived risks of breast cancer and intentions to engage in preventive measures

As breast cancer is the most prevalent cancer among women in Singapore, encouraging them to engage in preventive measures becomes increasingly important. This study aims to take a closer look at the influence of attention to media, interpersonal communication, news elaboration, and knowledge on women’s (aged between 30 and 70) perceived risks of breast cancer and their intentions to engage in preventive measures in Singapore. Attention to media, frequency of interpersonal communication, fatalistic belief, and knowledge structure density were found to be associated with risk perception of breast cancer among Singaporean women. Findings also showed that frequency of interpersonal communication, risk perception, elaboration, and factual knowledge were positively associated with women’s intentions to take up preventive measures such as breast self-examination, clinical breast examination, and mammography. Implications for theory and practice were discussed.     

Estimating default barriers from market information

Brockman and Turtle [J. Finan. Econ., 2003, 67, 511–529] develop a barrier option framework to show that default barriers are significantly positive. Most implied barriers are typically larger than the book value of corporate liabilities. We show theoretically and empirically that this result is biased due to the approximation of the market value of corporate assets by the sum of the market value of equity and the book value of liabilities. This approximation leads to a significant overestimation of the default barrier. To eliminate this bias, we propose a maximum likelihood (ML) estimation approach to estimate the asset values, asset volatilities, and default barriers. The proposed framework is applied to empirically examine the default barriers of a large sample of industrial firms. This paper documents that default barriers are positive, but not very significant. In our sample, most of the estimated barriers are lower than the book values of corporate liabilities. In addition to the problem with the default barriers, we find significant biases on the estimation of the asset value and the asset volatility of Brockman and Turtle.     

A closed-form solution to American options under general diffusion processes

This paper investigates American option pricing under general diffusion processes. Specifically, the underlying asset price is assumed to follow a diffusion process in which both the dividend yield and volatility are functions of time and the underlying asset price. Using the generalized homotopy analysis method, the determination of the early exercise boundary is separated from the valuation procedure of American options. Then, an exact and explicit solution for American options on a dividend-paying stock is derived as a Maclaurin series. In addition, the corresponding optimal early exercise boundary and the Greeks are obtained in closed-form solutions. A nonlinear sequence transformation, the Padé technique, is used to effectively accelerate the convergence of the partial sums of the infinite series. As the homotopy constructed in this paper is based on a generalized deformation with a shape parameter and kernel function, the error of the homotopic approximation could be reduced further for a fixed order. Numerical examples demonstrate the validity, effectiveness, and flexibility of the proposed approach.     

Valuation of Discrete Dynamic Fund Protection Under Lévy Processes

Abstract

This paper investigates the valuation of discrete dynamic fund protection (DFP) under Levy processes. Specifically, the analytical solution of discrete DFP under Lévy processes is obtained in terms of Fourier transforms. The derivation uses Spitzer’s formula and leads to a recursion on computing the characteristic function of the maximum protection-to-fund ratio using the Fourier inversion. DFP can then be valued efficiently and accurately via the fast Fourier transform. The pricing behavior of the discrete DFP is numerically examined using several Levy processes, such as geometric Brownian motion, jump-diffusion models, and variance gamma process. Numerical experiments confirm that the proposed approach produces highly accurate discrete DFP values within 1 second.     

变动成本法的实际运用

变动成本法与完全成本法在理论上各有差异,变动成本法的优点是将成本与产量密切联系,但对外编制会计报表时,现行会计制度要求按完全成本法编制,本文着重探讨完全成本法和变动成本法的综合运用,达到既满足企业内部管理的需要,又满足对外编制会计报表的要求。     

黑龙江省桦南至宝清地区金矿床特征及成矿条件

通过对本区的成矿特征,区域地质成矿条件分析,指出区域矿产分布的规律性,对寻找大型金及金属矿产具有重要的价值。     

刍议价值链成本会计与效益成本法

传统的成本管理方法存在着弊端,随着经济形势的变化,新的成本管理方法应运而生,将价值链分析法运用到成本会计中,采用效益成本法分析价值链每一环节成本,有利于降低成本,提高企业效益。     

网络环境下图书馆工作探讨

随着计算机、多媒体、通信技术的迅猛发展，计算机网络正以强大的信息提供及检索能力而风靡全球,将人类带入信息时代,改变了人们的生活和工作方式。计算机网络对图书馆工作也产生了革命性的影响,从根本上改变了图书馆收集、整理、传递和使用信息的方式。从图书的采访到流通等一系列手工作业逐渐被电脑操作所代替,并全方位实现自动化,现代检索方式也已步入以数据库为核心带动信息存储、检索等服务手段的全面电子计算机化。网络环境下的图书馆不仅包含书刊实体馆藏，还包括以网络信息资源为主的“虚拟馆藏”,主要包括存储于计算机中的电子图书和期刊、各类联机信息数据库、各类光盘、软件产品、电子出版物等。