iTunes University and the classroom: Can podcasts replace Professors?

iTunes University, a website with downloadable educational podcasts, can provide students the opportunity to obtain professors’ lectures when students are unable to attend class. To determine the effectiveness of audio lectures in higher education, undergraduate general psychology students participated in one of two conditions. In the lecture condition, participants listened to a 25-min lecture given in person by a professor using PowerPoint slides. Copies of the slides were given to aid note-taking. In the podcast condition, participants received a podcast of the same lecture along with the PowerPoint handouts. Participants in both conditions were instructed to keep a running log of study time and activities used in preparing for an exam. One week from the initial session students returned to take an exam on lecture content. Results indicated that students in the podcast condition who took notes while listening to the podcast scored significantly higher than the lecture condition. The impact of mobile learning on classroom performance is discussed.     

嵌入式MIDI文件格式解析设计与实现

建立在嵌入式系统平台上的电子乐谱阅读器可以代替传统纸质乐谱和谱架的组合成为乐谱阅读的理想方式,因此在嵌入式系统上阅读MIDI等文件格式的数字乐谱具有重要的意义。本文详细说明了从一个MIDI文件解析出五线谱信息的全过程,介绍了MIDI文件格式以及在MIDI格式读取的过程中遇到的种种问题的解决方法。     

基于音乐内容分析的音频认证算法

提出一种新颖的基于音符分割和模糊分类的音乐内容认证方法.该算法打破了传统音频认证所采用的固定长度分割方式,将音乐信号分割成一系列具有完整语义信息的不等长音符片段作为认证的基本单元,结合动态时间规整DTW(dynamic time warping)对齐技术,有效解决了大多数现有算法都存在的对同步失真脆弱的问题.在每个音符片段计算基于半阶音符类Chroma的鲁棒Hash值,根据原始音乐与待认证音乐之间Hash值差异的统计特性和时间分布特性,对3种新定义的度量指标进行模糊分类从而得到最终的认证结果.对于未通过认证的音乐信号系统还可以进行篡改区域的检测.实验结果表明,该算法能够有效区分可容许操作和恶意篡改,同时在篡改定位方面具有较高的精度.     

Semantic integration of audio content providers through the Audio Commons Ontology

A broad variety of audio content is available online through an increasing number of repositories and platforms. Resources such as music tracks, recorded sounds or instrument samples may be accessed by users for tasks ranging from customised music listening and exploration, to music making and sound design using existing sounds and samples. However, each online repository offers its own API and represents information through its own data model, making it difficult for applications to exploit the plurality of online audio and music content on the web. A crucial step toward integrating audio repositories in a flexible manner is a shared basis for modelling the data therein. This paper describes and extends the Audio Commons Ontology, a common data model designed to integrate existing repositories in the audio media domain. The ontology is designed with the involvement of users through surveys and requirements analyses, and evaluated in-use, by demonstrating how it supports the integration of four relevant repositories with heterogeneous APIs and data models. While this work proves the concept in the audio domain, our proposed methodology may transfer across a broad range of media integration tasks.     

音乐可视化研究综述

随着计算机技术的发展,音乐可视化日益得到研究机构和公司的重视,出现了各种音乐可视化系统。作为一种新的可视化技术,音乐可视化更多地关注音频和图形、图像的关系,是跨音乐、数字音频、图形学、图像处理、虚拟现实等领域的又一新的研究方向,在娱乐、教育、艺术和商业中具有广阔的应用前景。本文介绍了音乐可视化的概念和分类,探讨了音乐可视化的研究内容与国内外研究进展,分析了当前亟待解决的问题,并展望了未来的发展趋势。音乐可视化是一种新的概念系统,但也存在很多问题需要解决,其研究具有很强的理论和实用意义。     

流文件MP4文件的核心技术

在MPEG4标准中，包括场景信息、对象信息、管理控制信息等信息都是以二进制形式进行编码并存放在流文件MP4中。MP4文件包含了与媒体数据时间序列相关的时间、结构、媒体信息(例如音频／视频表达文件)，并通过轨道将它们联系在一起。本文重点介绍流文件MP4中的下列关键技术：与创建MP4文件相关的场景描述、对象描述、场景描述与对象描述之间的关系以及MP4流文件的组成机制和基于网络播放MP4流文件机制等，并基于MP4文件格式实现了汉字显示技术，这些内容有助于在实际研究中创建MPEG4流文件和应用MPEG4流技术。     

基于WAV文件的独奏乐曲信号中的乐谱识别

大多数乐谱识别工作都是在MIDI格式文件下进行的,而音乐数据大多采用音频格式存储,为此讨论一种从WAV音频文件的独奏乐曲信号中识别出乐谱的方法。采用离散余弦变换（DCT）结合能量比对的手段,并提出了一种变化音最少法则：以十六分音符对应的时值作为步长,将乐曲信号分为若干个子段;对每个子段进行一维DCT操作,提取基音频率;对相邻子段进行能量比对,查找音符的端点;利用变化音最少法则,生成乐谱。实验表明此方法具有良好的识别效果。     

基于遗传算法的智能作曲技术研究

为了利用遗传算法进行智能作曲,对由计算机自动生成音符序列和音频文件的具体问题进行了讨论。计算机根据预先设定的参数生成初始乐段群体,将对各乐段的人工评估结果作为适应度函数值,分别设定选择、交换和突变规则,通过时值修正来解决进化过程中乐曲每小节各音符的时值之和的不稳定问题,完成了音符序列的计算机生成问题。音频文件的产生通过建模和编码的方法实现。建立表示振幅与频率、时值之间关系的振动模型,其频率因子和时值因子分别取自音符编码中音高分量所映射的频率值和时值分量所映射的时间,根据此模型,结合数字音频技术,最终生成WAV音频文件,从而完成了音符到音频文件的转换。与目前MIDI形态的计算机音乐相比,WAV形态的计算机音乐具有很强的丰富性、灵活性和稳定性。实验表明,利用这种交互式遗传算法所创作的乐曲能基本满足部分人的情感表达需要和审美标准,对促进计算机音乐技术的发展有重要的科学意义。     

基于非功能语义的语义Web服务匹配方法研究

目前,语义Web服务匹配方面的研究主要集中在基于服务功能性信息的语义匹配上,但是,充分利用非功能语义信息有助于提高服务匹配的精度。非功能语义信息主要是文本描述,因此,基于非功能语义的服务匹配转化为文本相似度的问题。为了支持中文,本文根据《知网》来计算文本相似度,详细介绍了词语相似度、概念相似度和义原相似度的计算方法,并进行了实验,实验结果显示加入非功能语义虽然查全率有所下降,但查准率有很大的提高,进而证明非功能语义可以提高服务匹配的精度。     

User feedback based enhancement in web search quality

Of late, there has been a paradigm shift in web searching from the content based searching to the connectivity based or more commonly known as hyperlink based (or simply link based) searching. But, both the content based approach as well as the link based approach are objective ones, which are totally dependent on the effectiveness of their “feature extraction” mechanisms, with no apparent consideration to the preference of the searcher. In this work, a “user satisfaction” guided web search procedure is proposed. We calculate the importance weight of each document viewed by the user based on the feedback vector obtained from his actions. This document weight is then used to update the index database in such a way that the documents being consistently preferred go up the ranking, while the ones being neglected go down. Our simulation results show a steady rise in the satisfaction levels of the modeled users as more and more learning goes into our system. We also propose a couple of novel additions to the web search querying techniques.     

Personal orchestra: a real-time audio/video system for interactive conducting

We present the first multimedia system to conduct a realistic electronic orchestra. Users can control tempo, dynamics, and instrument emphasis of the orchestra through natural conducting gestures with an infrared baton. Using gesture recognition and tempo adjustment algorithms, the system plays back an audio and video recording of an actual orchestra that follows the users conducting in real time. A major achievement of this system is its ability to vary playback speed in real time while avoiding audio artifacts such as pitch changes. The system has been deployed as an exhibit and has become a major attraction of a large Vienna-based music exhibition center.An erratum to this article can be found at     

Implementing situation-aware and user-adaptive music recommendation service in semantic web and real-time multimedia computing environment

With the advent of the ubiquitous era, many studies have been devoted to various situation-aware services in the semantic web environment. One of the most challenging studies involves implementing a situation-aware personalized music recommendation service which considers the user’s situation and preferences. Situation-aware music recommendation requires multidisciplinary efforts including low-level feature extraction and analysis, music mood classification and human emotion prediction. In this paper, we propose a new scheme for a situation-aware/user-adaptive music recommendation service in the semantic web environment. To do this, we first discuss utilizing knowledge for analyzing and retrieving music contents semantically, and a user adaptive music recommendation scheme based on semantic web technologies that facilitates the development of domain knowledge and a rule set. Based on this discussion, we describe our Context-based Music Recommendation (COMUS) ontology for modeling the user’s musical preferences and contexts, and supporting reasoning about the user’s desired emotions and preferences. Basically, COMUS defines an upper music ontology that captures concepts on the general properties of music such as titles, artists and genres. In addition, it provides functionality for adding domain-specific ontologies, such as music features, moods and situations, in a hierarchical manner, for extensibility. Using this context ontology, we believe that logical reasoning rules can be inferred based on high-level (implicit) knowledge such as situations from low-level (explicit) knowledge. As an innovation, our ontology can express detailed and complicated relations among music clips, moods and situations, which enables users to find appropriate music. We present some of the experiments we performed as a case-study for music recommendation.     

New sites,new sounds: An internet resource on the music and musicians of free improvisation 1

The Internet is seen as providing information services and products discrete and separate from print‐based media, but so far there have been few manifestations of actually useful services, though this is changing. This paper describes one such multimedia resource that has been running for thirty months, on a specific aspect of music: European Free Improvisation. After an overview of free improvisation, the content of the web site is described — audio, video, and collaborative full text material ‐ as well as involvement in a current EU‐funded ACT project, GAIA.     

Mobile audio distribution

This paper presents a new concept for future audio entertainment distribution. The idea is to make music a service, not a product. All the music in the world will be available to the users wherever they are with an enhanced mobile telephone. The system has push and pull services. The push services send content that suits the users' profiles to a device without any user interaction. Thus there are no real-time demands and content can be sent with low priority or scheduled for a period with spare capacity. The pull services require user interaction and need more bandwidth, since users expect a reasonable response time. This approach solves the extensive problems with copyright infringement. The content is encrypted and can only be accessed via a key. Since users will have access to unlimited music resources for a reasonable price, they will not bother to copy music illegally.