基于隐含导频的长距离IM/DD DFT-S-OFDM无源光网络的实验系统研究

基于隐含导频、超奈奎斯特镜像混叠和直接检测,首次在IM/DD光通信系统中使用基于隐含导频（ST）的信道估计和均衡方式,通过实验实现了速率为20 Gb/s的正交相移键控（QPSK）离散傅里叶变换扩展正交频分复用（DFT-S-OFDM）信号传输832 km的光通信系统.使用隐含导频信道估计（ST-CE）方法来均衡信道的线性损伤,关键是把隐含导频（ST）算术叠加在数据信号上,而不占用单独的时隙. 通过对接收到的信号进行1阶统计分析估计出精确的信道. 为了增加传输距离,根据超奈奎斯特镜像混叠的方法增加接收机带宽来补偿色散引起的功率衰落. 结果显示,在长距离强度调制/直接检测（IM/DD）DFT-S-OFDM无源光网络（PON）系统中,采用ST-CE能得到更高的频谱效率,且其信道估计性能与TA-CE相当. 该方法节省了带宽,提高了频谱利用率.     

论管理过程中的柔性化领导

随着科学管理的不断发展,传统的发号施令的领导方式越来越不适应当今社会各种组织发展的需要,柔性化的领导逐渐兴起并占据重要地位。这种以人为本的领导方式,要求领导者自身要有较强的亲和力和协调能力、较高的耐心和责任感、善于进行共情式领导。在管理中领导者要有效地实施柔性化管理,就必须以人为本,建立有效的激励机制;重视调控组织成员的情绪情感;加强人际沟通与协调,团结合作;提高非权力因素的影响力。     

物联网中区块链技术的应用与挑战

随着物联网技术的快速发展和广泛应用,分布式网络环境下的身份验证、数据隐私、网络安全等问题变得更加重要,而这些问题可以通过引入区块链技术来得到有效解决.该文简述了区块链的基本概念,介绍了区块链在物联网中的应用场景,并对当前一些相关工作的成果进行了综述;介绍了针对物联网场景下区块链底层技术的研究以及区块链物联网所面临的问题与挑战,希望能对未来区块链物联网的研究有一定的参考价值.     

多元函数可微性研究

从降低偏导连续的条件和利用高阶偏导来判别多元函数可微性,并把相应结果推广到n元函数中。     

《多高层建筑结构设计》多媒体CAI系统开发

介绍了利用Visual Basic语言和Authorware作工具开发《多高层建筑结构设计》多媒体CAI系统的全过程,并介绍了该系统的主要功能,同时讨论了开发过程中的一些关键技术及其实现方法．     

VB6.0下利用PC机串口实现导弹整流罩壁厚的测量

为实现导弹整流罩壁厚的测量,介绍了在VB6．0环境下发挥PC机RS-232串口的作用,使用串行通讯控件MSCornm构成数据采集时间间隔为0．1秒的测量控制系统,介绍了控制系统软件中一些关键环节的处理过程。     

Countering medical nihilism by reconnecting facts and values

A pessimistic strain of thought is fomenting in the health studies literature regarding the status of medicine. Ioannidis’s (2005) now famous finding that “most published research findings are false” and Stegenga’s (2018) book-length argument for medical nihilism are examples of this. In this paper, we argue that these positions are incorrect insofar as they rest on an untenable account of the nature of facts. Proper attention to fallibilism and the social organization of knowledge, as well as Bayesian probabilities in medical reasoning, prompt us to ask why the cynics expect the results of quantitative studies to be incontrovertibly true in the first place. While we agree with Ioannidis and others’ identified flaws in the medical research enterprise, and encourage rectification, we conclude that medical nihilism is not the natural outcome of the current state of research.     

Epistemic benefits of the material theory of induction

C. D. Broad famously labelled the problem of providing our inductive practices with a proper justification “the scandal of philosophy” (Broad, 1952). Recently, John Norton has provided a dissolution of this problem (2014). According to Norton, inductive inference is grounded in particular facts obtaining within particular domains (J. Norton, 2003b, 2010, 2014). Because the material theory does not involve a universal schema of induction, Norton claims it dissolves the problem of induction (which implies that such universal schemas cannot be justified).In this paper, I critically evaluate Norton's dissolution. In particular, I argue that the problem of induction is an epistemological problem, that Norton's material theory entails an externalist epistemology, and that it is a common feature of such epistemologies that they dissolve the problem of induction. The upshot is that the material theory is not unique in its ability to reap the specifically epistemic benefits of dissolving the problem of induction, and thus that the epistemic advantages of the material theory over extant alternatives in this regard are fewer than it may appear at first sight.     

The total cost of misclassification in credit scoring: A comparison of generalized linear models and generalized additive models

This study examines whether the evaluation of a bankruptcy prediction model should take into account the total cost of misclassification. For this purpose, we introduce and apply a validity measure in credit scoring that is based on the total cost of misclassification. Specifically, we use comprehensive data from the annual financial statements of a sample of German companies and analyze the total cost of misclassification by comparing a generalized linear model and a generalized additive model with regard to their ability to predict a company's probability of default. On the basis of these data, the validity measure we introduce shows that, compared to generalized linear models, generalized additive models can reduce substantially the extent of misclassification and the total cost that this entails. The validity measure we introduce is informative and justifies the argument that generalized additive models should be preferred, although such models are more complex than generalized linear models. We conclude that to balance a model's validity and complexity, it is necessary to take into account the total cost of misclassification.     

A structural interpretation of measurement and some related epistemological issues

Measurement is widely applied because its results are assumed to be more reliable than opinions and guesses, but this reliability is sometimes justified in a stereotyped way. After a critical analysis of such stereotypes, a structural characterization of measurement is proposed, as partly empirical and partly theoretical process, by showing that it is in fact the structure of the process that guarantees the reliability of its results. On this basis the role and the structure of background knowledge in measurement and the justification of the conditions of object-relatedness (“objectivity”) and subject-independence (“intersubjectivity”) of measurement are specifically discussed.