Large deviations, hypotheses testing, and source coding for finite Markov chains

Let{X_{n}} n geq 1be a finite Markov chain with transition probability matrix of strictly positive entries. A large deviation theorem is proved for the empirical transition count matrix and is used to get asymptotically optimal critical regions for testing simple hypotheses about the transition matrix. As a corollary, the error exponent in the source coding theorem for{X_{n}}is obtained. These results generalize the corresponding results for the independent and identically distributed case.     

基于证据距离与不确定度的证据组合方法

Dempster-Shafer证据理论是信息融合领域中的一种重要的理论与方法.然而在实际应用中,Dempster证据组合规则无法有效处理高冲突证据组合问题,往往引发反直观结果.针对这一问题,提出一种新的加权证据组合方法.该方法同时利用证据距离和证据不确定度来生成权重进而修正待征组合证据,并取得合理的组合结果.实验结果表...     

My favorite experiment: EMP, lightning leaders, and hypotheses

The author describes his experience on electromagnetic pulse generated by a lightning bolt. The author also gained a lot of respect for the electromagnetic energy that must be released from an airborne nuclear explosion, seeing as how one blast can easily destroy all electronics within a 1,000 mi radius.     

直流小电流标准源的检定与不确定度评定

利用KEITHLEY6517静电计为测量标准,采用标准表法,实现对直流小电流标准源准确、可靠的检定。通过对其测量不确定度的评定,证明可圆满地实现最大允许误差为±0.5％及以下的直流小电流标准源的检定,从而增强了对直流小电流标准源的量值传递能力。     

The Short Message Service: Standards,infrastructure and innovation

The Short Message Service (SMS) is a teleservice developed by the Global System for Mobile Communication in the mid-1980s for second-generation mobile networks. SMS is made up of standards, protocols and infrastructure that make text messaging the most popular data service on mobile networks. The teleservice has been used in all subsequent generations of mobile telephony. This article discusses the development of the SMS teleservice standards (GSM 03.40), how it has influenced mobile telephony infrastructure, and how it remains a lasting communication innovation today. It historicizes text messaging standards and their technical realization by describing the network architecture and elements required for SMS transmission. This article illustrates how SMS standards and infrastructure represent a significant innovation to mobile telephony in the late twentieth century.     

Adoption of just-in-time manufacturing methods at US- andJapanese-owned plants: some empirical evidence

Since the early 1980s, when Japanese manufacturing firms in a number of industries-including auto, electronics, and machinery-achieved high levels of international competitiveness, Japanese manufacturing practices-particularly those associated with just-in-time manufacturing (JIT)-have attracted considerable attention in North America. Transfer to the United States of JIT is characterized by special production management practices involving inventory and quality control, industrial relations, and supplier-manufacturer relationships. Because so many different aspects of plant operation are involved, the transfer of JIT requires a substantial effort on the part of US manufacturers. Despite this barrier, anecdotal evidence suggests that substantial transfer of Japanese production methods has taken place and that this transfer has had a significant impact on the performance of US manufacturing plants. However, there is little empirical evidence of this process that is based on broad samples of plants and workers from various manufacturing industries. The purpose of this paper is to help fill this gap in the literature. Using a sample of US and Japanese-owned manufacturing plants in the United States in three different industries, we show that the implementation of JIT has improved many of the performance measures for these US manufacturing plants     

国内外激光加工产业和市场发展概况

描述了最近几年国内外激光加工产业概况、市场动向和发展前景，并进行了比较分析。介绍了几种发展迅速的新兴激光加工机的发展趋势。     

方正软件:看准市场瞄准市场

作为安全领域的一支生力军，方正软件自成立之初就清醒地认识到，只有看准市场、瞄准市场才是生存和发展的“尚方宝剑”。因此他们一开始就将自己定位于全系列安全产品解决方案供应商和服务提供商领域。公司凭借其研发实力，推出了拥有自主产权的方正方通系列防火墙和方正Sniper入侵监测系统，并在2002年3月入资控股欧洲最大的防病毒软件厂商熊猫软件(中国)有限公司，完成其全系列厂商的角色定位和周密细致的规划部署。事实证明，单一的产品和技术已无法满足用户的需求。立体防护、全面防护已经成为信息安全发展的必然趋势。显然，方正软件…     

融合多元经验模态分解与Hilbert空间填充曲线的sEMG处理方法

基于卷积神经网络(convolutional neural network, CNN)的表面肌电信号(surface electromygraphy, sEMG)手势识别算法通常将一维sEMG转换成二维肌电图作为CNN的输入。针对sEMG瞬时样本量偏少、以及一维sEMG转换成二维肌电图时带来的局部时序特征丢失等问题,提出了将多元经验模态分解(multivariate empirical mode decomposition, MEMD)算法与Hilbert空间填充曲线相结合的方法,以提升手势识别算法的准确率。采用开源数据集NinaPro-DB1作为实验数据集;通过MEMD算法对sEMG进行分解;将分解后的本征模态函数(intrinsic mode functions, IMFs)作为Hilbert曲线的填充域(Hilb-IMFs)映射成二维肌电图;选择DenseNet作为手势识别的基本网络。实验结果表明,提出的方法相对于传统信号升维方法在手势识别准确率上约有4%的性能提升,验证了该方法的有效性。     

The Effects of Message Intensity on Receiver Evaluations of Source, Message and Topic

This study investigated the consequences of increased levels of expressed message intensity on receivers' subsequent evaluations of the source and topic of the message, in addition to their perceptions of the message itself. A basic message was prepared in which a previously neutral source attacked a relatively low-salience topic. The intensity with which the source stated his attitudinal position was systematically varied by the alternative insertion of verbs and modifiers of known intensive value. This created two experimental messages, one of low intensity, the other of high intensity. Subjects read one of the messages and responded via rating scales. Obtained results provided partial support for the experimental hypotheses, in that the high intensity message was judged as clearer and its source as more dynamic than the low intensity message. A secondary analysis based solely on perceived message intensity conformed even more closely to the experimental predictions. Messages rated as being highly intense were also rated as clearer and more logical, and having sources who were judged to be more trustworthy, more qualified and more dynamic.     

平台维护类软件开源策略研究

在共享经济的影响和推动下,软件应用的开源工作也将面临新的机遇。当前,开源软件被认为源代码可以被公众使用的软件。开源软件可以降低软件研发成本,有助于降低采购成本,缩短工期,提升软件代码功能。尤其在平台型维护工作中,加大开源软件工作力度,将有益于维护工作软化,提升工作效率。文章对平台维护型软件开源工作的必要性进行了阐述,提出平台维护型软件开源工作思路、措施,以及要规避的风险。     

Conceptualizing organizational politics as a multidimensionalphenomenon: empirical evidence from a study of technological innovations

While there is a growing literature on organizational politics (OP), the phenomenon has not been operationalized in a way that can be useful for analyzing the technological innovation process. To address this gap, OP was measured along two dimensions: general innovation-related organizational politics (GIOP) and project-specific organizational politics (PSOP) at the formulation and implementation stages of the technological innovation process. Results support the authors' contention that OP is a multidimensional phenomenon     

Dilemmas,uncertainty, risks,and board performance

This paper traces the origins of the words risk, uncertainty, governance and development and argues that a deeper understanding of each allows more effective decision taking in the boardroom. It argues that the role of the board of directors is to balance and rebalance continuously their irresolvable dilemma — ‘how do we drive our enterprise forward while keeping it under prudent control?’ It argues that it is the board’s role to focus on uncertainty, rather than risk, and this requires a different set of intellectual skills from board members to be able to cope with monitoring a range of diverse scenarios. This is crucial for a board to develop stronger ways of both leading their organisation and of ensuring the connectedness of the learning within and between the board and the operational unit’s risk taking. It advocates that to achieve this a board must develop new ways of learning — especially of thinking strategically and becoming more sensitised to the dynamics of their changing external environments. This will take them well beyond the comforts of their specialist managerial disciplines and into the true world of directing. The paper demonstrates the importance of continuous learning in reducing organisational uncertainty and risk. It uses the ‘Learning Board’ process and model as the central processor of both strategic and operational learning to create an annual rhythm for the board’s year.     

Human factors in color-based image retrieval: an empirical study on size estimate accuracies

In color histogram based image retrieval, a user query specification forms a histogram to be matched with those of the images in the database. The accuracy of this specification determines the matching latitude and affects directly the effectiveness of the retrieval process. The retrieval process suggests some relevant human factors, such as people’s ability to estimate percentages and individual characteristics such as training, experience, and background. A two-part laboratory study was made to understand people’s ability to estimate percentages of single-block and multiple-block color. The results can be applied to enhance image retrieval systems. For example, the results provide different ranges of estimates, based on statistical percentiles. Retrieval systems can use these to determine appropriate values for retrieval control parameters. The statistics can be used to help determine likely recall and precision performance. Overall, the study provides deeper understanding of people’s estimate of color percentages in images.     

The uncertainty principle: global, local, or both?

We address the issue of the relation between local quantities and the uncertainty principle. We approach the problem by defining local quantities as conditional standard deviations, and we relate these to the uncertainty product appearing in the standard uncertainty principle. We show that the uncertainty product for the average local standard deviations is always less than or equal to the standard uncertainty product and that it can be arbitrarily small. We apply these results to the short-time Fourier transform/spectrogram to explore the commonly held notion that the uncertainty principle somehow limits local quantities. We show that, indeed, for the spectrogram, there is a lower bound on the local uncertainty product of the spectrogram due to the windowing operation of this method. This limitation is an inherent property of the spectrogram and is not a property of the signal or a fundamental limit. We also examine the local uncertainty product for a large class of time-frequency distributions that satisfy the usual uncertainty principle, including the Wigner distribution, the Choi-Williams distribution, and many other commonly used distributions. We obtain an expression for the local uncertainty product in terms of the signal and show that for these distributions, the local uncertainty product is less than that of the spectrogram and can be arbitrarily small. Extension of our approach to an entropy formulation of the uncertainty principle is also considered.     

基于证据源和组合规则双修正的证据合成

针对冲突证据合成时传统证据合成和单一修正改进方法存在的问题,提出了新的证据源预处理和组合规则双修正的证据合成方法.利用夹角余弦理论,计算证据向量距离后转化得到权重系数,依据权重系数对证据进行重新概率分配,完成证据源修正;之后用修正的动态合成规则,进行修正证据的合成;同时提出了算法分析模型.实例结果验证了算法在证据合成时具有最优结果、较强通用性和稳定性,可应用于信息融合、不确定信息决策等领域.     

Key-Dependent Message Security: Generic Amplification and Completeness

Key-dependent message (KDM) secure encryption schemes provide secrecy even when the attacker sees encryptions of messages related to the secret-key sk. Namely, the scheme should remain secure even when messages of the form f(sk) are encrypted, where f is taken from some function class $\mathcal{F}$ . A KDM amplification procedure takes an encryption scheme which satisfies $\mathcal{F}$ -KDM security, and boosts it into a $\mathcal{G}$ -KDM secure scheme, where the function class $\mathcal{G}$ should be richer than $\mathcal{F}$ . It was recently shown by Brakerski et al. (TCC 2011) and Barak et al. (EUROCRYPT 2010) that a strong form of amplification is possible, provided that the underlying encryption scheme satisfies some special additional properties. In this work, we prove the first generic KDM amplification theorem which relies solely on the KDM security of the underlying scheme without making any other assumptions. Specifically, we show that an elementary form of KDM security against functions in which each output bit either copies or flips a single bit of the key (a.k.a. projections) can be amplified into KDM security with respect to any function family that can be computed in arbitrary fixed polynomial-time. Furthermore, our amplification theorem and its proof are insensitive to the exact setting of KDM security, and they hold in the presence of multiple-keys and in the symmetric-key/public-key and the CPA/CCA cases. As a result, we can amplify the security of most known KDM constructions, including ones that could not be amplified before. Finally, we study the minimal conditions under which full-KDM security (with respect to all functions) can be achieved. We show that under strong notion of KDM security, the existence of fully homomorphic encryption which allows to encrypt the secret-key (i.e., “cyclic-secure”) is not only sufficient for full-KDM security, as shown by Barak et al., but also necessary. On the other hand, we observe that for standard KDM security, this condition can be relaxed by adopting Gentry’s bootstrapping technique (STOC 2009) to the KDM setting.