ACCELERATION AMBIGUITY FUNCTION OF RADAR SIGNALS AND ITS APPLICATION

High acceleration of radar targets is analyzed using Acceleration Ambiguity Function(AAF). The acceleration resolution based on AAF is defined. The AAF and acceleration resolution of rectangle pulse signal are derivated and the conclusion that its acceleration resolution is in inverse proportion with the square of its duration is drawn. In the end, these conclusions are applied to the parameter designing and performance evaluation for a certain type of pulse Doppler radar.     

基于MVC设计模式和J2EE架构的Web信息系统框架研究

介绍了MVC设计模式、J2EE架构、Struts框架和Turbine框架，分析了其优缺点，在此基础上建立了一套高效实用的应用框架AAF。该框架由AAF Application Framework，Business Beans，JSP Pages和AAF Tag Library四部分组成．实现了模型、控制和视图3部分功能。最后对该框架的实际应用效果进行了分析，提高了代码的重用率，增强了程序的可读性．可缩短开发周期、降低开发成本。     

浅议AAF和MXF文件格式及其在全台网业务系统中的应用

本文主要从AAF和MXF的主要特点、AAF和MXF的数据内容、AAF与MXF的比较、AAF和MXF的应用等方面。探讨与分析了AAF和MXF文件格式及其在电视台全台网业务系统中的应用。     

互联互通的障碍与标准化

本文通过对目前各系统间互联互通实现方式的分析,说明了阻碍互联互通实现的主要障碍,并通过描述理想的互联互通方式,提出了统一标准才是解决问题的根本出路.同时对目前得到较多支持的AVI、MXF和AAF文件格式进行了简要介绍.     

Structural characterization of N-acetyl-2-aminofluorene (AAF) adducts to guanine and deoxyguanosine via a molecular mechanics, semi-empirical, and density functional theory cascade

After hepatic activation, the carcinogen N-acetyl-2-aminofluorene (AAF) may form a major or a minor adduct with DNA, both in vivo and in vitro. The structure of the minor adduct has not been experimentally determined but is believed to be of importance due to its persistence in vivo. In the present study, four varieties of modified AAF have been studied computationally; AAF bonded to C8 of guanine or deoxyguanosine (major adduct), and AAF bonded to N² of guanine or deoxyguanosine (minor adduct). A computational cascade was employed to search for low-energy conformers of each molecule. Each adduct was subjected to a series of systematic searches of thousands of structures using molecular mechanics. After convergence with respect to the search parameters was obtained, the resulting conformers were then geometry optimized via the semi-empirical AM1 method. Subsets were then submitted to non-local Becke–Perdew density functional theory geometry optimization. The structures thus predicted of the guanine major adduct compare favorably with NMR and X-ray crystallographic data. The major adducts reveal an energetic preference for adoption of one of two orientations, with guanine or deoxyguanosine oriented either perpendicular to the fluorenyl ring moiety or approximately 45° with respect to the fluorenyl structure. Repulsion between the ribose sugar and acetyl group in deoxyguanosine disrupts the ‘ideal’ dihedral angles observed in the guanine adduct. Results for the N² structures similarly point toward two general conformer classes, one of which is characterized by hydrogen bonding between the acetyl O and the H bonded to N² of guanine, and the other by minimization of repulsion between the guanine structure and the acetyl group. In the case of deoxyguanosine, results differ somewhat from guanine due to an attractive interaction between the acetyl group and the ribose O5′. These results provide substantial motivation for further experimental work on AAF adduct complexes.     

电视制作流程中元数据应用的研究

电视制作每一个环节都涉及元数据操作,要么是收集、产生元数据,要么是使用元数据来工作,不同环节里元数据具有不同的特性。本文在最通用的层面论述了元数据在电视制作过程中如何呈现;在网络信息化的背景下,通过使用、管理元数据如何实现高效的生产管理的可能途径。     

Distributed space‐time block codes with embedded adaptive AAF/DAF elements and opportunistic listening for multihop power line communication networks

We consider the multihop power line communication (PLC) networks of one source, two repeaters, and one destination. In the previous scheme, when the repeaters receive the retransmission data from the source, they use the traditional distributed space‐time block code (DSTBC) with all decode‐and‐forward (DAF) elements to transmit the data, and they do not consider the incorrect decoding. The original contribution is that we propose a novel DSTBC scheme with embedded adaptive DAF/amplify‐and‐forward (AAF) elements for data retransmission in multihop PLC networks with existing opportunistic listening (OL) protocols. The new scheme has two types (instead of only one type as in the previous scheme), and, in the second type, the coding matrix for data retransmission can use either all DAF elements or hybrid AAF/DAF elements depending on the correctness of OL results. The advantage is to avoid a loss of diversity because of incorrectly received data at the relays. The effectiveness of the proposed scheme is shown in the simulation results. For the impulsive noise parameter δ = 0.8 and worst case background noise (narrowband interference and colored noise) at bit error rate 10⁻³, our proposed system has 1 dB gain over the previous scheme with the traditional DSTBC with all DAF elements. Copyright © 2015 John Wiley & Sons, Ltd.     

Reflective secondary optical elements for fresnel lens based concentrator modules

This paper reports on the development of secondary optics for concentrator photovoltaic (CPV) modules. It focuses on reflective secondary optics designed for high concentration modules using fresnel lenses as the primary concentrating optics. The development of the secondary optics was guided by the idea of designing an optical element suitable for cost effective mass production. The primary concentrating optics of a CPV module can direct only a limited part of the solar aureole (the immediate surroundings of the sun) onto the solar cell. The same applies to light impinging non‐perpendicular to the optical axis of the module (e.g., due to misalignment of the module). Therefore, one of the main functions of reflective secondary optics is to redirect light onto the solar cell that would otherwise not reach it. In order to analyze the performance of secondary optical elements (“secondaries”), a measurement setup is introduced that measures the angular photocurrent response of a CPV device with highly parallel light. This response is referred to as the “angular acceptance function” (AAF). The AAF is used to estimate the performance of the CPV device under various conditions with differing circumsolar radiation (CSR). A CPV test module was manufactured featuring III–V triple‐junction solar cells, a fresnel lens panel as the primary concentrator optic, and the newly developed reflective secondary. The results of a 6‐month outdoor measurement period are presented and compared to the performance of a reference module as well as to the results of the indoor AAF measurements. Copyright © 2011 John Wiley & Sons, Ltd.     

演播室制作流程网络化的探讨

随着IT设备性价比迅速提高,低成本的甚至消费级的IT产品用于电视制作成为现实。电视后期制作、播出系统网络化自动化已经开始普及,但是演播室制作、前期制作的自动化仍有很大发展空间。本文借鉴国外一个成功的例子,探讨如何在开放性标准化技术的基础上,利用低成本的IT设备实现无带化和自动化的演播室制作流程,以及如何与后期编辑系统无缝连接。相信本实例对国内许多电视台、制作机构具有启发意义。