Short-term and long-term competition between providers of shrink-wrap software and software as a service

Software as a service (SaaS) has moved quickly from a peripheral idea to a mainstream phenomenon. By bundling a software product with delivery and maintenance service, SaaS providers can effectively differentiate their products with traditional shrink-wrap software (SWS). This research uses a game theoretical approach to examine short- and long-term competition between SaaS and SWS providers. We analyze the factors that affect equilibrium outcomes, including user implementation costs, SaaS provider’s operation efficiency, and quality improvement over time. Bundling software with service lowers software implementation cost for users, and our results suggest that it increases equilibrium prices. In providing software services, SaaS providers have to incur significant operation cost. In the long run, service operation cost may significantly affect SaaS firm’s ability to improve its software quality.     

Dual-thread parallel control strategy for ophthalmic adaptive optics

To improve ophthalmic adaptive optics （AO） speed and compensate for ocular wavefront aberration of high temporal frequency, the AO wavefront correction is implemented with a control scheme including two parallel threads： one is dedicated to wavefront detection and the other conducts wavefront reconstruction and compensation. With a custom Shack-Hartmann wavefront sensor that measures the ocular wave aber-ration with 193 subapertures across the pupil, AO achieves a closed-loop updating frequency up to 110 Hz, and demonstrates robust compensation for ocular wave aberration up to 50 Hz in an AO scanning laser ophthalmoscope.     

激光自外差相干测量中分布反馈半导体激光器电流调谐非线性的补偿方法

半导体激光器的电流调谐非线性对自外差相干测量的精度影响很大.研究了分布反馈半导体(DFB) 激光器的电流调谐特性,据此提出一种数学模型补偿方法.利用已知光程差下的差拍频率,建立了动态调频 系数的数学模型.以此模型对DFB激光器的电流调谐非线性进行补偿,可以将差拍信号频率预测值的相对误差 减小约3%,提高了系统的测量精度.数学模型补偿方法简化了测量系统的结构,适用于高精度的电流调谐 激光在线测量系统.     

Extensible Software Systems in Oberon

Abstract

Extensible software systems play an important role in prototyping environments where a fast compile-and-test turnaround is required. Typically, extensible software systems combine ways to reuse code, an approach to object-oriented programming, and ways to preserve state from one session to another. In this article we introduce the Oberon system from the perspective of an extensible system. In Oberon, the stated requirements manifest themselves as separate hierarchies related to modularity, the type system, runtime system organization, and persistency. We discuss issues related to these hierarchies and the approaches selected in Oberon for their implementation. The article is mainly a short introduction to Oberon and a summary of what has been accomplished with this system.     

An empirical study of ICASE learning curves and probability bounds for software development effort

In this paper, we investigate the existence of learning curves in software development. Under the assumption of independent and identical distribution (iid) of programmer’s experience and identical effort-experience learning curve relationship for different programmers, we illustrate the existence of an exponentially decreasing learning curve relationship between a programmer’s effort and his/her ICASE tool experience, and show that the effort-experience relationship is inelastic when a programmer’s ICASE tool experience is low. We analyze the impact of our assumptions on actual software development effort, and propose a tight probability upper bound and a central-limit theorem based probability estimator for estimating the approximate probability that the software development effort will be less than or equal to a certain number. Examples to illustrate the use of the probability estimator are also provided.     

球对称带电时空中Dirac粒子的Hawking效应

该文避开求解能－动张量的困难，在视界附近直接求解Ｄｉｒａｃ方程，得到球对称带电黑洞的事件视界位置和Ｈａｗｋｉｎｇ辐射温度．进一步分析表明Ｈａｗｋｉｎｇ辐射温度是时间坐标尺度变换下的补偿效应．     

记数抽样检查方案设计与分析软件研制

利用VisualC++6.0Windows开发设计了抽样方案分析与设计软件。软件集成多种功能于一窗口,直观性强,操作方便,计算速度快,不仅可对现行抽样方案检索与分析,而且还可对一次、二次、五次和序贯抽样方案进行设计与分析,并作计算机模拟,可供抽样检查和抽样方案设计人员使用。     

Four Kinds of Microwave Measurements to Make Use of an Automatic Slotted-Line System

An automatic slotted line system controlled with the micro-computer IBM 80486 which we have developed had been reported. In this paper, the measuring principles and the software designs of impedance, attenuation, phase shift and detection law of diode measurement to make use of this system will be described, some typical measurement results will be given. This method is adaptable for MM-Wave band and other Micro-wave band.     

真空热试验通用软件平台工作模式与关键技术

为了改善试验测控软件在通用化、模块化设计、控制算法、试验过程信息化管理等方面的诸多不足,研制航天器热试验通用软件平台。该平台融合了计算机技术、虚拟仪器技术和网络技术,不仅实现从试验准备、试验工况运行、试验数据显示到实验结果分析等工作的自动化,而且应用多项关键技术使该平台成为一个有机整体并具备广泛的通用性、灵活的配置能力、便捷的人机接口。文中重点介绍了该平台的4中工作模式,分别为单机模式、分布式模式、云计算模式、集中控制模式。通过工作模式的介绍说明该平台如何在各种规模真空热试验设备上应用。热试验通用软件平台能够提高热试验的自动化程度、提高热试验的可靠性、有利于热试验技术经验的积累。