一种新型的喷泉编码技术研究

喷泉编码是一种新颖的编码技术,核心算法使用简单的同位及线性方程式,编译码只需要很低的处理功能,随着其学术理论的日益完善,获得了越来越多的应用;文章介绍了喷泉编码的基本概念和特点,详细地分析了LT码的编译码过程,介绍了两种良好的度分布函数,并对度分布函数的优缺点进行了讨论,最后简述了喷泉编码的应用前景。     

基于Android的多媒体应用开发

为了开发出丰富多彩的移动多媒体应用程序,借助Android平台提供的良好API接口,通过程序设计开发实现了多媒体应用程序——音乐播放器。首先对Android的系统架构进行了简要的概述,随后在此基础上对Android应用程序的特点及开发组件分别进行了介绍,最后通过设计实现一个音乐播放器对Android多媒体应用程序开发方法进行了说明演示。该设计实现的音乐播放器既可以播放资源文件中的音乐文件,也可以选择手机SD卡中的本地音乐文件进行播放。     

融合内容表示的度量排序学习推荐模型

融合内容语义信息的推荐模型可以有效缓解音乐推荐系统中的数据稀疏性和冷启动问题.然而,这些模型是通过最小化预测评分误差学习用户与音乐的全局关系,忽略了用户和音乐隐式特征的细粒度差异.此外,内容语义特征是以推荐任务无关的无监督学习方式提取的,从而导致不精确推荐.为此,本文提出了融合内容表示的度量排序学习推荐模型,该模型是以个性化排序最优化为目标的概率图模型,利用度量学习从全局和细粒度层面挖掘用户音乐偏好.为了解决冷启动推荐问题,本文建立了与推荐任务相关的监督学习策略训练内容语义特征提取模型.在KKBOX和MIGU数据集上的实验结果表明,提出的模型显著提升了冷启动音乐推荐的效果,在不同稀疏度数据集上的鲁棒性得到了显著增强.     

改善LT码性能的预译码集优化方法研究

喷泉码是第一种与码率无关的编码方式.LT码是在删除信道下性能优异的稀疏随机线性喷泉码.与传统编码相比,大大降低了编译码的复杂度.通过分析影响LT码性能的预译码集,提出了优化LT码预译码集的方法.主要在编码端改变初始预译码集大小以及修改度为2的生成矩阵,在译码端利用编码冗余情况来破解译码停止集,同时消除短环.大量的数据仿真结果表明本文方法对译码性能有明显的改善.     

基于最小统计与MMSE-LSA的语音增强

提出了一种基于最小统计及短时对数谱幅度最小均方误差估计单通道语音增强算法,并在此基础上对其进行了修正。噪声功率谱估计不需要VAD进行有无语音的检测,并在每帧数据都进行更新,可跟踪变电平噪声。该算法在MMSE—LsA准则下得到谱增益函数,并考虑到纯净声音信号频谱特性,对增益函数进行了修正。实验结果表明,该算法可有效去除噪声,在消除音乐噪声的同时对语音信号产生很小的失真,并易于实时处理。     

基于度分布合并和可译集优化的LT码度分布设计方案

喷泉码的度分布对喷泉码的编译码性能有着十分重要的影响.目前常用的度分布在源数据码长较长时具有较好的性能,但在码长较短时,性能有明显下降.本文给出一种LT码度分布的构造方法.该方法先对二进制度分布进行调整,然后将其与鲁棒孤子度分布进行有机结合,再通过优化可译集合值来进一步优化度分布函数,得到一种当源数据为短码长时也有较好性能的度分布,即修正二进制-鲁棒孤子度分布.仿真结果证明,采用这种度分布对源数据进行LT编码时,相比较二进制度分布和鲁棒孤子度分布,其译码性能得到了明显提高,并且码长越短,性能提高越明显.     

Emerging Scanning Probe–Based Setups for Advanced Nanoelectronic Research

Scanning probe microscopy (SPM) refers to a family of techniques that have become essential to study many different properties of materials and devices at the nanoscale. All of them have in common that they use an ultrasharp probe tip to scan the surface of a sample. However, although many of these techniques are interrelated, some of them have become very sophisticated and require specific and deep study. While there are plenty of review articles available for most of these techniques, newer developments need to be carefully analyzed in a critical manner in order to promote their development. In this progress report, some of the newest SPM‐based developments that are expected to generate a larger impact in the field of nanoelectronics are discussed, and critical advice on how to improve each of them is provided. In particular, the combination of wear and electrical tests; scanning gate microscopy; the integration of conductive atomic force microscopy into scanning electron microscopy; and the integration of a scanning probe into transmission electron microscopy, multiprobe scanning tunneling microscopy, multiprobe atomic force microscopy, and fountain‐pen nanolithography are focused on.     

现代信息技术下的音乐传播

现代信息技术传播的世界被音乐进入,并在与音乐的互动过程中发生了一系列变化,从经验素材与逻辑规律相结合的角度来分析,这在一定程度上成为一件必然之事。本文在现代信息技术的视角下观察音乐特性对其的接驳与碰撞,并对“联购信息”在音乐与现代信息技术互动融合过程中发挥的价值进行思考。     

图书馆背景音乐广播系统的设计

以重庆工学院图书馆工程建设为背景,设计了一种背景音乐广播系统。该系统已在重庆工学院图书馆成功使用,具有智能化控制程度高,使用可靠,工作稳定等特点。     

The convergence of mobile data phones,consumer electronics,and wallets: Lessons from Japan

Japan is leading the world with the adoption of new mobile data services such as Internet services and with a resulting boost in data ARPU (average revenue per user). In the development of these services, many functions have been integrated into mobile handsets, which has resulted in a convergence of, so far, separate consumer electronic devices. This article addresses the following questions: What are the drivers of this process? What could European players, in particular the European policymakers do to catch up? According to our research, a major driver of the process in Japan is tough competition among operators, which in turn is driven by factors such as competition in mobile radio infrastructure. The author arrives at the following conclusions for European policies: (1) There should be more awareness of the Japanese lead, e.g., of the crucial role of Internet push e-mail. (2) Europe could benefit from more operators willing to bear the risk of introducing new technologies. (3) For a successful introduction of infrastructure competition, it could make sense to make spectrum bands available with European-wide licenses.