The Economics of Public Beta Testing

A growing number of software firms now rely on public beta testing to improve the quality of their products before commercial release. While the benefits resulting from improved software reliability are well recognized, some important market‐related benefits have not been studied. Through word‐of‐mouth, public beta testers can accelerate the diffusion of a software product after its release. Additionally, because of network effects, public beta testers can increase users’ valuation of a product. In this study, we consider both reliability‐related and market‐related benefits, and develop models to determine the optimal number of public beta testers and the optimal duration of testing. Our analyses show that public beta testing can be profitable even if word‐of‐mouth and network effects are the only benefits. Furthermore, when both benefits are considered, there is significant “economies of scope”—the net profit increases at a faster rate when both word‐of‐mouth and network effects are significant than when only one benefit is present. Finally, our sensitivity analyses demonstrate that public beta testing remains highly valuable to software firms over a wide range of testing and market conditions. In particular, firms will realize greater profits when recruiting public beta testers who are interested in the software but unable to afford it.     

西部少数民族地区承接东部地区产业转移问题研究

本文结合我国西部少数民族地区承接东部地区产业转移的现状,总结出目前我国西部少数民族地区承接产业转移的主要模式,并在此基础上剖析西部少数民族地区承接东部地区产业转移的经济效应,最后提出了若干对策建议。     

《城南旧事》改编中的散文化风格问题探析

电影《城南旧事》改编的成功,与其笼统地归功于对小说原著的忠实,不如更准确地说,是电影忠实于并强化了小说原著那种以"淡淡的哀愁,沉沉的相思"为基调的散文化风格。本文试图通过对小说文本、电影剧本和剪辑完成的电影之间的详细比较,考察从小说到电影这一改编过程中对风格问题的处理,探析散文式电影改编的艺术技巧和成功经验。     

就业迁移的人力资本差别效应——以长三角为例

随着我国城市化的快速发展,人口迁移流动在城市社会生活中的影响日益突出。人口迁移流动必然引起“人”自身所拥有的人力资本的动态配置。文章主要利用2000年全国第五次人口普查迁移数据等有关数据资料,分析长三角16城市就业迁移的人力资本差别效应。研究发现,就业迁移对长三角各城市人力资本具有显著的差别效应,并且长三角内的就业迁移与长三角外的就业迁移对长三角各城市人力资本提升或稀释效应也有明显差别。研究还发现,就业迁移导致长三角人力资本城际差异缩小,尤以上海与其他15城市的差距缩小更为明显。     

Evaluating unintended program outcomes through Ripple Effects Mapping (REM): Application of REM using grounded theory

Several evaluation models exist for investigating unintended outcomes, including goal-free and systems evaluation. Yet methods for collecting and analyzing data on unintended outcomes remain under-utilized. Ripple Effects Mapping (REM) is a promising qualitative evaluation method with a wide range of program planning and evaluation applications. In situations where program results are likely to occur over time within complex settings, this method is useful for uncovering both intended and unintended outcomes. REM applies an Appreciative Inquiry facilitation technique to engage stakeholders in visually mapping sequences of program outcomes. Although it has been used to evaluate community development and health promotion initiatives, further methodological guidance for applying REM is still needed. The purpose of this paper is to contribute to the methodological development of evaluating unintended outcomes and extend the foundations of REM by describing steps for integrating it with grounded theory.     

新型农村合作医疗制度建设绩效评价

文章以分析新农合建设模式与目标为基点,利用2009年中部四省12个县的调查数据,从农民的“主观感受”和制度实施的“客观效果”两个层面,对新农合建设绩效进行了分析和评价。研究发现,新农合的福利性得到了大多数农民的认同,但补偿率较低,农民满意率也较低;新农合的福利效应比较明显,但保障能力有待提高;新农合存在的主要问题,不是宏观制度设计而是微观运行机制的问题。提升新农合建设绩效,应合理调整起付线、封顶线和补偿比例以提高农民的受益率;加强监督管理,重点防止医疗供方道德风险;加大财政投入,在精算的基础上扩大筹资规模,重在基层医疗机构基础设施建设和人才培养等。     

宽带对中国经济增长影响的实证分析

本文运用2000年至2011年中国宽带渗透省际面板数据,研究了宽带与中国经济增长之间的关系,发现宽带引入和渗透对中国经济增长起到了显著推动作用,2000年到2011年的数据表明,宽带渗透率每增长10% 能带动人均GDP年增长率增加约0.19个百分点。分析表明宽带渗透对经济增长的贡献存在一定的网络效应,当宽带渗透率达到约10%后,宽带渗透对人均GDP年增长率的贡献率增加。此外,宽带对中国经济增长的影响具有区域差异性,宽带对于东部、中部经济发展的推动作用显著,而对西部还不明显,可能的原因是西部信息化应用水平与东、中部地区还有较大差距。截止2012年,中国宽带渗透水平以及宽带传输速率与发达国家还有明显差距,并有进一步加大的趋势,实施宽带中国战略具有现实紧迫性。     

固定效应面板线性回归模型的移动分块经验似然估计

本文针对固定效应面板线性回归模型中特意误差项为任意形式序列相关情形,提出了移动分块经验似然估计方法,并给出了大样本性质。模拟研究表明：该方法适用于特意误差项序列相关形式已知和形式未知两种情形,较Baltagi和Li（1994）以及Gon?alves（2011）提出的方法有效。本文采用该方法对CO2排放量与城市化水平之间的关系进行了实证分析,结果表明：城市化水平对CO2排放量有显著影响,不同城市化阶段对CO2排放量影响不同。     

Random balanced resampling: A new method for estimating variance components in unbalanced designs

Variance components in factorial designs with balanced data are commonly estimated by equating mean squares to expected mean squares. For unbalanced data, the usual extensions of this approach are the Henderson methods, which require formulas that are rather involved. Alternatively, maximum likelihood estimation based on normality has been proposed. Although the algorithm for maximum likelihood is computationally complex, programs exist in some statistical packages. This article introduces a simpler method, that of creating a balanced data set by resampling from the original one. Revised formulas for expected mean squares are presented for the two-way case; they are easily generalized to larger factorial designs. The results of a number of simulation studies indicate that, in certain types of designs, the proposed method has performance advantages over both the Henderson Method I and maximum likelihood estimators.     

影响外语环境下语用能力发展的非语言因素

语用能力就是正确得体地使用语言进行交际的能力。根据Verschuerenm“使用语言就是不断选择语言”的观点,本文讨论了与社会文化密切相关的认知结构和心理因素对选择语言形式得体进行交际过程产生的影响。