基于互素对称阵的近场源定位

针对近场源定位中存在的孔径损失问题,该文提出了一种新的近场源定位算法。该算法采用互素对称阵列,使得阵元间距不必限制于1/4信号波长。首先构造一个特殊的四阶累积量矩阵,进而采用MUSIC算法估计信源方位角,然后在每个估计方向上搜索距离。该算法将近场源2维定位问题转化为多次1维搜索,且参数自动配对。互素对称阵的使用有效地扩展了阵列孔径,提高了空间分辨概率和参数估计性能。计算机仿真验证了该算法的有效性。     

Microsoft,Open Source and the software ecosystem: of predators and prey—the leopard can change its spots

Over the past few years, Microsoft has promoted a project called ‘Shared Source Initiative’, which allows certain customers (e.g., research institutions and independent software vendors) access to its source code on a restricted basis. As part of this initiative, Microsoft introduced some licences that appear to give unrestricted access to source code and closely resemble ‘traditional’ Open Source licences. In July 2007, two of these ‘shared source’ licenses (the Microsoft Community Licence and the Microsoft Permissive Licence) were submitted to the Open Source Initiative (OSI) and subsequently approved by the OSI as certified Open Source licences. Thus Microsoft's Shared Source Initiative and its partial embrace of Open Source appear to be a significant step towards closing the ideological rift between developers of proprietary software and the Free/Open Source software movement, and more than just another attempt to appease consumers and/or critics in terms of software transparency. By analysing the ‘evolution’ of Microsoft's Shared Source licences, this article aims to shed some light on the question what is needed for a ‘predator’ (i.e., proprietary, software developer) such as Microsoft to become ‘prey’ (i.e., be part of the Open Source community). This article concludes that, although Microsoft's efforts are to be lauded, it is highly unlikely that the company will embrace fully the Open Source philosophy in the near future.     

Seismic safety of lifelines—an optimum design method

Lifeline systems are vulnerable to two types of hazards arising from potential earthquake sources. These are the hazard of a fault-rupture strike on elements of a lifeline system and the hazard of overstress induced in different elements of the system because of the ground vibration. An optimum design method is presented in this paper for the design of a lifeline system for a maximum accepted probability of failure because of any of the two modes of failure. The method may be used to determine an optimum path between a number of fixed points which represent supply or demand stations in the system.     

Dynamical sources in information theory: Fundamental intervals and word prefixes

A quite general model of source that comes from dynamical systems theory is introduced. Within this model, some basic problems of algorithmic information theory contexts are analysed. The main tool is a new object, the generalized Ruelle operator, which can be viewed as a “generating” operator for fundamental intervals (associated to information sharing common prefixes). Its dominant spectral objects are linked with important parameters of the source, such as the entropy, and play a central rôle in all the results.     

LTE网络高价值区域识别与分析方法研究

通过对LTE网络中高价值区域的识别与分析,可有效保证网络建设投资合理性、提升网络优化效率、节约各类资源投入。同时,高价值场景是中国移动“五高一地”重点关注的场景类型,但缺乏有效识别手段。本文通过LTE网络信令数据、MR数据、工参数据、经分数据等多维数据源关联分析,充分挖掘了数据价值,建立了价值评估体系,从经济价值和社会价值两个层面对网络发展情况进行多维度评估和分析,实现了高价值区域的聚合与自动生成,开展了区域价值分析,解决了高价值场景识别和规划优化工作中的痛点和难点问题,为提高规划优化投资效率提供了理论指导和技术支撑。     

Analytical model of a superluminescent diode

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Comparison of Data from an IAQ Test House with Predictions of an IAQ Computer Model

One of the objectives of EPA's indoor air quality (IAQ) program is to provide guidance on the impact of indoor sources on IAQ. A computer model, EXPOSURE, was developed to assist in this effort. EXPOSURE calculates pollutant concentration as a function of time for each room of the building. EXPOSURE includes effects of sources, sinks, room-to-room air movement, and air exchange with the outdoors. Several experiments designed to evaluate the impact of indoor sources on IAQ are described. Measured concentrations are compared with concentrations predicted by an IAQ model. The measured concentrations are in excellent agreement with the predictions. The model predictions and the experimental data demonstrate the importance of sinks in determining long-term IAQ.     

我国核工业废放射源安全管理

废放射源易于在管理上失去控制，从而酿成事故，对人类和环境造成危害。本文分析了我国废放射源产生的原因，介绍了我国核工业废放射源的现状与安全管理的技术路线和策略，提出了当前所面临的主要问题。     

Perfluorinated alkylated substances in the aquatic environment: An Austrian case study

Perfluorinated alkylated substances (PFAS) are of global interest due to their occurrence and persistency in the environment. This study includes surface waters and sediments for the analysis of eleven PFAS. The PFAS studied can be grouped in perfluoroalkyl carboxylates (PFCAs), perfluoroalkyl sulfonates (PFS) and perfluoroalkyl sulfonamides (PFSA). The two most important compounds are perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS). These two substances showed the most significant values for surface water samples with maximum concentrations of 21 ng l⁻¹ for PFOA and 37 ng l⁻¹ for PFOS. Sediment samples from seven Austrian lakes and the river Danube were studied. Whereas PFSA and PFS were not detected in any sediment sample PFCAs were detected in most of the lake samples in concentrations up to 1.7 μg kg⁻¹ dry wt. PFOA, perfluorohexanoic acid (PFHxA) and perfluoroheptanoic acid (PFHpA) were detected in all Danube river sediment samples in concentrations varying from 0.1 up to 5.1 μg kg⁻¹ dry wt. For the various sampling points the proportional mass flows deriving from wastewater discharges were calculated. Whereas only up to 10% of the average flow is discharged wastewater up to more than 50% of the PFAS mass flows in the rivers can be attributed to wastewater discharges. Besides wastewater different other pathways as emissions from point sources, further degradation of precursor products, runoff from contaminated sites or surface runoff as well as dry and wet deposition have to be considered as relevant sources for PFAS contamination in surface waters.     

防止备自投装置动作过负荷方案的实践

根据南京地区电网的接线特点,分析了低压网络备用电源自投装置的动作所带来利弊,探讨出适合于本电网特点的防止备自投装置动作过负荷的技术方案。