有关语音识别技术的研究

语音识别是将音频数据转换成文本或者其他形式的计算机可以处理的信息。这里简单介绍语音识别技术的发展历史和现状,阐述了典型语音识别系统的基本原理,对语音识别的基本方法和识别过程进行深入分析,探讨语音识别技术发展过程中的难点问题,给出了相应对策。     

可见光通信及其关键技术研究

可见光通信系统采用白光发光二极管(LED)作为光源,因而系统具有通信与照明的双重作用,极大地节约了能源.描述了可见光通信的结构与特点,对可见光通信的一些关键技术做了简单的研究,并介绍了可见光通信的发展动态.     

基于纠错算术码的信源信道自适应联合编解码系统

对信源信道自适应联合编码方法进行了研究,提出了一种新的基于纠错算术码的联合信源信道编解码系统。该系统在编码端利用算术码内嵌禁用符号实现信源信道一体式编码,即利用马尔科夫信源模型和根据信道状态信息自适应地调整禁用符号概率大小从而调整编码码率来实现信道自适应;在解码端,推导出了基于MAP的解码测度数学公式并基于此测度公式提出了一种改进的堆栈序列估计算法。与传统的信道自适应编码算法不同,该自适应编码算法只需调整一个参数:禁用符号,且理论上可获得连续可变的编码码率。实验结果表明,与经典的Grangetto联合编码系统以及分离编码系统相比,所提出的编码系统具有明显改善的性能增益。     

大气及典型地物光学特性数据库

大气及典型地物光学特性数据库是一个集地面波谱测量数据、地物成分物理、化学参数数据和环境特征、遥感图像、实地图片数据于一体的大气及典型地物光学特性知识库,目的是为定量遥感的理论与应用研究提供一个综合化、系统化和专业化的遥感波谱科学实验平台。它将在典型地物波谱与图像数据积累的基础上,以波谱数据的知识化、定量化和实用化为目标,完成地物波谱、环境参数间的相互配套。创新点在于实现了地物波谱特性数据库与大气信息数据库以及地物偏振信息数据库的结合,不仅能为用户提供观测波谱,而且能够提供配套的地物偏振信息以及大气信息,并有助于获取和积累典型地物的偏振信息数据以及大气信息数据,有效地组织、管理这些数据,使大气及典型地物光学特性数据库能服务于多种研究目的。     

码位重叠快调频OCDMA系统的多址干扰研究

设计并制作了基于光纤光栅的光编码/解码器,实现单干扰用户、数据速率2.5Gb/s的码位重叠快跳频OCDMA(SO-FFH OCDMA)实验系统.分析SO-FFH OCDMA系统中的多址干扰,并与传统FFH OCDMA系统中的多址干扰进行比较.实验结果表明,多址干扰将恶化SO-FFH OCDMA系统性能,在单个干扰用户的条件下,该系统仍能正确解码数据速率2.5Gb/s的用户数据信息.     

On the time‐frequency symbol density of FBMC/QAM systems

Filter bank multicarrier (FBMC) systems suffer from an inherent interference, which needs to be eliminated at the detection process. Orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) is a well‐known FBMC system, which transmits real‐valued symbols. In OFDM/OQAM, the time and frequency spacing between adjacent transmitted symbols are organized such that the inherent interference becomes pure imaginary and can be removed by a real‐taking operation. Although OFDM/OQAM provides the maximal bandwidth efficiency, it falls short in handling the spatial multiplexing techniques in multi‐input multi‐output channels. In this regard, those modified FBMC systems, which transmit complex QAM symbols (FBMC/QAM) are used to support the spatial multiplexing techniques. In this article, we present a novel matrix formulation for the FBMC/QAM transmission procedure. On the basis of this presentation, we show that the maximal achievable time‐frequency symbol density of FBMC/QAM, with the ability of perfectly removing the interference, is equal to that of the primer OFDM/OQAM.     

Why Taddeo and Floridi did not solve the symbol grounding problem

The symbol grounding problem (SGP), which remains difficult for AI and philosophy of information, was recently scrutinised by Taddeo and Floridi (Solving the symbol grounding problem: A critical review of fifteen years of research. Journal of Experimental & Theoretical Artificial Intelligence, 17, 419–445, 2005; A praxical solution of the symbol grounding problem. Minds and machines, 17, 369–389, doi:10.1007/s11023-007-9081-32005, 2007). However, their own solution to SGP, underwritten by Action-based Semantics, although different from other solutions, does not seem to be satisfactory. Moreover, it does not satisfy the authors' principle, which they dub ‘Zero Semantic Commitment Condition’. In this paper, Taddeo and Floridi's solution is criticised in particular because of the excessively liberal relationship between symbols and internal states of agents, which is conceived in terms of levels of abstraction. Also, the notion of action seems to be seriously defective in their theory. Due to the lack of the possibility of symbols to misrepresent, the grounded symbols remain useless for the cognitive system itself, and it is unclear why they should be grounded in the first place, as the role of grounded symbols is not specified by the proposed solution. At the same time, it is probably one of the best-developed attempts to solve SGP and shows that naturalised semantics can benefit from taking artificial intelligence seriously.     

基于符号特征的QR码识别算法

在传统QR码识别算法基础上,提出一种利用QR码自身的符号特征进行识别定位的改进算法。对采集到的图像进行二值化处理,由符号特征定位QR码在采集图像中的位置,通过改进的双线性变换校正在采集过程中引起的图像几何形变,并通过逐模块垂直投影提取条码信息。实验结果表明,该算法具有识别时间短、识别率高等特点。     

一种新的突发OFDM传输系统定时和载波频率捕获联合算法

提出了一种新的正交频分多路(0FDM)传输系统定时和载波频率捕获联合算法．该算法仅需要一个训练符号，既用于定时恢复，也用于载波频率捕获，额外开销量小，因此，提出的算法适合于突发模式的0FDM传输系统．定时和频率捕获算法的实现均在时域进行，而且0FDM帧同步和符号同步能一次完成，简化了同步实现的复杂度．由于使用自相关处理，定时恢复对频率偏差具有较强的鲁棒性．此外，训练符号中参考符号的重复扩展了频率估计范围，频率捕获的范围完全满足突发0FDM传输系统的要求．仿真结果表明，即使在频率选择性衰落信道中，提出的算法也能快速地实现定时和频率捕获。     

计及典型日选取与源荷灵活性调节的优化调度研究

针对电网面临的反调峰特性和新能源消纳问题,提出一种计及源荷侧灵活性调节资源的电力系统优化调度模型。首先,根据负荷特点采用改进SSE-PFCM聚类算法求取负荷典型日。其次,基于负荷用户对电价变化的不同响应行为,提取出具有需求响应潜力的两类负荷,并且分别为其构建计及乐观响应隶属度的模糊负荷转移率模型以及需求价格弹性模型。然后,计及需求响应不确定性模型以及火电机组深度调峰,以系统综合运行成本最小为目标构建优化调度模型,采用引入步长弹性系数的改进粒子群算法求解。最后,以改进IEEE 30节点系统为例进行多种场景的仿真计算分析,结果表明所提策略能够有效提升系统可再生能源的消纳能力和系统运行的经济性。