基于时长调整技术的低速率语音编码算法

研究并实现了一种新的低速率语音编码方案。通过将时长调整算法作为声码器的预处理和后处理,不需要修改声码器结构就能灵活地实现低速率语音编码。文中选择基于STFT的时长调整算法、SOLA算法、WSOLA算法分别与2.4kb/s和600b/s的声码器相结合,仿真结果显示,新方案进一步降低了语音编码速率,为低速率语音编码研究提供了一条有效的新思路。     

一种基于DCT和PSOLA的语音变换方法

文中提出了一种基于离散余弦变换(DCT)和基音同步叠接相加(PSOLA)的语音变换方法。此方法可以自由调整源语音的基音频率、能量分布和时长,以达到变换要求,并且变换后的语音具有较高的质量。变换方法首先对基音标记过的语音段通过DCT进行基音频率和能量分布的调整,之后再通过PSOLA法进一步对基音频率进行修正。实验表明,此方法在男女声变换中,能够使变换前、后语音的性别感觉明显变化,并且保持了较高的语音质量。     

一种基于非负矩阵分解的语音增强算法

文章提出了一种基于非负矩阵分解的语音增强算法。该算法包括两个阶段,训练阶段和增强阶段。训练阶段通过非负矩阵分解算法对纯净的噪声频谱进行训练,得到噪声字典矩阵,保存其作为增强阶段的先验信息。增强阶段首先通过非负矩阵分解算法对带噪语音的频谱进行分解,然后联合噪声字典矩阵和推导得到的相应迭代公式对语音字典矩阵和语音编码矩阵进行估计,重构增强语音。仿真结果表明,文中增强方案在抑制背景噪声,提高信噪比和减少语音失真方面要优于传统的语音增强算法。     

基于谐波加噪声模型的语音转换算法

文章分析了语音的谐波加噪声模型,给出了基于谐波加噪声模型的男/女声转换算法流程,利用高斯混合模型(GMM)分别实现了谐波分量和噪声分量特征参数的转换。文中利用Matlab进行了仿真实验,验证了算法的有效性,对转换后的语音质量进行了ABX测试,并计算其谱失真进行客观评价,测试结果表明文中所述算法,较好的实现了语音转换。     

基于语音采样点倒置的图像信息隐藏算法

为提高图像传输的安全性,将基于音频采样点倒置的算法用于基于语音的图像信息隐藏算法中,引入了静音检测(voice activity detection,VAD)技术筛选适宜隐藏信息的语音段,并采用Logistic混沌映射对秘密图像预处理。实验表明,该算法实现了盲提取,较大地降低了提取误码率,嵌入图像信息后的载体语音具有良好的透明性和鲁棒性。     

一种对丢包具有鲁棒性的语音编码算法—iLBC

文中介绍了一种适用于网络的,对丢包具有鲁棒性的语音编码算法——iLBC。iLBC在编码时先进行LPC分析,然后对LPC残差信号采用自适应码本编码,这个自适应码本与传统的CELP算法中的自适应码本不同,没有利用语音帧之间的相关性,使得iLBC算法对丢包具有鲁棒性;解码时如果有语音包丢失,则采用丢包隐藏(PLC)算法。介绍了iLBC编解码算法的基本原理;重点分析了iLBC的自适应码本编码方式以及丢包隐藏算法(PLC);比较了在丢包率相同的情况下,iLBC和ITU-T G.729A的MOS分,结果表明,iLBC更适合于有丢包的网络。     

一种基于AMDF和ACF的基音周期提取算法研究

文中提出一种基于短时平均幅度差分函数(AMDF)和短时自相关函数(ACF)的基音周期提取算法。首先,将每帧语音信号通过AMDF算法进行计算,然后把得到的AMDF数值再通过ACF算法进行计算,得出每帧信号的基音周期,最后运用动态平滑技术计算出最终语音信号的基音周期。通过仿真实现该算法,并同基于MAMDF和ACF的基音周期提取算法进行比较。     

基于α-β滤波算法的目标运动信息滤波与估计

针对目标运动量测信息的特点,通过分析α-β滤波算法,指出该算法常增益的特点影响其对机动目标的跟踪效果.为了克服这个缺点,给出了一种新的目标运动信息滤波和估计的自适应算法,该算法可直接利用构造的函数关系自适应调整α,β的值.仿真结果表明,该自适应α-β滤波算法对目标运动信息的滤波和估计具有较好的性能.     

控制律预测的再入滑翔飞行器轨迹预测算法

针对临近空间再入滑翔飞行器巡航段轨迹预测问题,提出了控制律预测的轨迹预测算法。通过分析和推导轨迹预测中的未知量及研究归纳巡航段的飞行方式和控制律,阐明轨迹预测的可行性;研究了平衡滑翔和跳跃滑翔2类轨迹的判别方法,并在此基础上设计了控制律预测的轨迹预测算法。最后仿真验证了算法的有效性,并研究了跟踪时长和起始点对轨迹预测精度的影响。结果表明该算法针对多种类型的轨迹都具有较高的预测精度;跟踪时长对预测精度影响较大,而跟踪起始点影响较小。     

一个基于LB/IHMM的高性能汉语连接数字语音识别系统

本文使用一种ＩＨＭＭ的简化训练算法，讨论了一个基于ＬｅｖｅｌＢｕｉｌｄｉｎｇ搜索算法，参考模式基于ＩＨＭＭ模型的高性能的汉语连接数字语音识别系统。文中详细描述了系统的特征提取、ＩＨＭＭ模型、训练过程和识别过程，以及系统用于特定人、多说话人和不认人语音识别的实验，并且对实验结果进行了分析和讨论。     

Terrorism,insurgency, kidnapping,and security in Africa's energy sector

Energy continues to serve as the bedrock of modern economies and the main driver of modern society. For Africa, the production and supply of energy resources such as crude oil, natural gas, uranium, coal, biomass, biofuels and other renewables are an important source of employment, rents, taxes, royalties and profits. This sector brings in several tens of billions of dollars of revenue annually. The production and delivery of such resources, however, depend on critical infrastructures such as pipelines, refineries, processing plants, terminals, rigs, electrical energy pylons, substations, pump stations, vessels, and tankers. These infrastructures have been attacked by terrorists, insurgents, vandals and saboteurs, all of whom see them as targets against which to register their grievances and extract concessions from the state. This paper is a chronological account of some of the documented incidents of terrorism, insurgency, kidnapping, destruction, sabotage, and human casualties suffered in the oil and gas sectors in Africa between 1999 and 2012. It is based on data extracted from the databases of the RAND Database of World Terrorism Incidents and the University of Maryland's Global Terrorism Database (GTD).     

Helping hands: civil–military cooperation and Italy's military operation abroad

In the Post-Bipolar Era the growing complexity of the military operations requires a new approach for the resolution of international crises. Since the end of the Cold War, peace support operations (PSO) have become the mainstay and principal occupation of most Western armies. At the same time, Italy has been one of the most important actors in such an area. The article focuses on the cooperation between military and civil components (a process called CIMIC) as a key variable in the Italian PSOs. We will analyse in detail the main lessons learned from past military interventions as well as the general context in which new tendencies are taking place. The maintaining of a minimum security frame becomes essential to fulfil activities ‘collateral’ to the mission: reconstructing services and infrastructure, food distribution, water and medication, law and order, de-mining, training of local forces, and supporting local institutions. These are the main tasks to obtain thrust and support from the population.     

Tacit support for terrorism: The rapprochement between the USSR and Palestinian guerrilla organizations following the 1967 war

This article demonstrates the inconsistent and wavering Soviet attitude towards national liberation movements in general and the Palestinian organizations in particular. Until the late 1960s, the Soviets viewed these organizations with suspicion, hesitating to engage in political dialogue with them. However, in the 1970s, political and military events in the region, as well as modifications in the Kremlin's Cold War strategies, led to a general shift towards the Middle East in Soviet foreign policy. Soviet leaders showed increased willingness to provide certain Palestinian organizations with arms with which to conduct terrorist activities against Israeli, pro-Israeli, Jewish and Western targets. The article explores the complex relations between Palestinian organizations and the USSR in the field of international terror. The study also exposes and analyzes the nature and content of Soviet–Palestinian arms dialogues and transactions. It provides clear evidence that Soviet policymakers and other luminaries were fully informed of, and sometimes directly involved in, these transactions and dialogues at the highest levels.     

A1 Qaeda and the radical Islamic challenge to western strategy

The September 11 global crisis prompted by the attacks on the World Trade Center and the Pentagon raises major questions concerning the nature and trajectory of terrorism in the post-Cold War global order. Hitherto, terrorism has been largely debated by analysts at the level of nation states. Terrorist and insurgent movements have also been largely anchored in nationalist and ethnic power bases even when they have sought to mobilise a transnational ideological appeal on religious or class grounds. There have been a few exceptions to this pattern such as the alliance between the German Baader-Meinhof group and the Japanese Red Army Faction, but even such international alliances as this did not, until at least the 1980s, presage anything like a global terrorist network necessitating a global strategic response. This study examines terrorism and global strategic responses.     

Helping hands: external support for the KNU insurgency in Burma

This article analyses to what extent the Burmese KNU insurgency made use of external support from states, refugees, and diasporas. Based on extensive fieldwork it is concluded that support from neighbouring states and refugees has for years kept the Karen rebellion alive. Western countries perceived forms of resistance to the illegitimate Burmese regime as just and have therefore played a crucial role in the continuation of conflict in Karen State. It is important that policymakers and donors as well as executing organizations continue to reflect critically on the way they exercise their work.     

基于GTST-DMLD-ESD的装备RMS建模仿真

装备的RMS是装备的重要设计参数,是影响战备完好和保障能力的关键因素.引入GTST-DMLD作为主要建模工具,建立起装备系统的RMS描述模型,以ESD为补充和扩展,对维修过程进行建模.并以GTST-DMLD-ESD模型作为装备RMS仿真的核心,对装备RMS仿真模型的总体框架进行了研究,并对各模块进行了较为详细的探讨.     

The UK,interrogation and Iraq, 2003–2008

The UK’s interrogation operations during the conflict in Iraq (2003–2008) are often portrayed by the media as involving significant amounts of mistreatment. This article demonstrates that these practices are not necessarily representative of the UK’s interrogation operations across this conflict. In doing so it contributes to the limited literature on the practice of interrogation and on the UK’s combat operations in Iraq. The UK’s interrogation capability, and therefore its intelligence-gathering capability, is shown to have rested primarily with the military’s Joint Forward Interrogation Team (JFIT). The JFIT suffered from limitations to the number, training and experience of its interrogators and interpreters. It is argued that maintaining a permanent, higher level of preparedness for interrogation by the British armed forces is desirable.     

Remembering and forgetting Mirambo: Histories of war in modern Africa

ABSTRACT

While the study of organised violence is considered essential to understanding the history of the West, and accordingly imbued with various layers of meaning and remembrance, war is widely regarded as inimical to the modern nation in Africa and stable development more broadly. Using examples drawn from primarily from East Africa, this paper considers the ways in which warfare in the deeper (‘precolonial’) past has been framed and envisioned in recent decades, in particular by governments whose own roots lie in revolutionary armed struggle and who began life as guerrilla movements. While in some cases particular elements of the deeper past were indeed mobilised in pursuit of contemporary political goals, in many other scenarios histories of precolonial violence were beheld as problematic and unworthy of remembrance. This paper highlights the paradox and ambiguity which has attended the memory of key aspects of Africa’s deeper past.     

Cyber sheiks and grassroots jihadis: the war in Syria and the devolution of the Bosnian Salafi communities

ABSTRACT

What was the scope of the Bosnian jihadi participation in the war in Syria? Did the Bosnian volunteers tend to join one particular faction? Why did the Bosnian youngsters decide to join the holy war in the Levant? Was this an organized and hierarchical process or was this a grassroots movement? Last, were all the Salafis in Bosnia supportive of this dynamic or did this process cause internal frictions? These are some of the questions that this research will try to answer.