The paper makes the analysis of the retrieval results with different fusion policies and shows that our method is promising in the content - based image retrieval 结果表明，所提出的新方法比基于颜色直方图的单样本检索性能好。
Machine learning and statistical modeling approach is a simple yet effective technique for image retrieval , but the retrieval performance is often dependent on a large number of training data 机器学习和统计方法是一种有效的提高检索性能的方法，但通常需要大量的训练样本才能达到满意的检索精度。
Compared with traditional text - based or content - based image retrieval system , this system not only improves the retrieval performance , but also makes the interaction between the human and computer more convenient 与基于文本或基于内容的图像检索系统相比，该系统既提高了检索性能，又使得人机交互更加便利。
The experiment shows that the retrieval accuracy of the system is above 70 % in few steps of relevant feedback ( five times in average ) , and the performance could increase steadily with it been used 经过试验测试，本文的图像检索系统可以在少量的反馈次数(平均5次)中达到进70的准确率，而且随着系统的使用次数的增多，检索性能会逐步增长。
The model constructed by this thesis based on mpeg - 7 , has standardized capability , at the same time can deal with different media formats . and its search capability has rather high level in precision and recall 本文构造的此种模型建立于国际标准mpeg - 7上,具有通用性,同时可以处理多种媒体格式,且在检索性能上达到较高水平的准确率和查全率。
In order to preprocess the text of aircraft fault , a new automatic indexing method based on n - gram is proposed . large quantities of experiments to adjust the parameters of lsi model are done so that the performance of case retrieval system is excellent 本文以系统的检索性能为依据通过大量的实验确定了潜在语义索引模型所使用的权值方案、 k值、相似度阈值等参数。
It can dynamically determine the structure information need to index according to real query loads and opti mization of index . second , to consider the effects of structural information on result relevance ranking , this dissertation proposes a ranking algorithm that consider both the frequency distribution and structural distribution of keywords in the result , and a dynamic element - oriented method to compute the weight of keywords 第二，为考虑xml数据中的结构信息对查询结果相关度值的影响，本文提出了一种综合考虑关键字频率分布特征和结构分布特征的查询结果相关度算法，以及一种基于节点的关键字权重计算法，取得了更优的检索性能。
In addition , the concept of scene centriod is introduced to represent video scene by averaging of all key frames inside a group of shots in the given video scene , which makes an audacious attempt for high - level video unit extraction and representation ; 4 ) according to the given sample video , shot and scene - based video retrieval methods are discussed respectively , and the evaluation pricinples are also discussed 进而，讨论了由场景中一组镜头的关键帧的质心表示场景关键帧，即场景质心的方法，从而为抽取高层的视频数据单元做出了大胆的尝试； d )从给定样本视频出发，分别讨论了基于镜头和场景的视频检索方法，并分析了检索性能评价的准则。
The experimental system extract the low - level features of images such as hsv histogram , the texture got from coexistence matrix , color correlogram , and according to the characteristic of our image database , design the evaluation function such as the average rank ratio to evaluate and compare the performance of different integration of different features including semantic , and validate the active effect of feedback using experiment results 该原型系统提取了hsv直方图、共生矩阵纹理、颜色相关图等底层特征，同时根据图像数据库的特点，设计了平均位置比值等评价函数对语义特征与底层特征的各种结合的检索性能进行了比较分析，并对反馈效果进行了实验验证。
The major difficulties include the following : the performance of most present retrieval methods deteriorates dramatically under noise ; it is very difficult to index audio data which is highly dimensional and of time sequence ) ; little work has been done on dynamic audio retrieval ; research in the semantic - level retrieval for audio music progresses hard and slowly due to the serious difficulties in extracting semantic information from audio music ) 主要问题有:大多数检索算法在有噪声的情况下检索性能明显下降;音频数据维数高且具有时序性,构建索引非常困难;缺少针对动态音频检索的研究;音频形式的音乐由于获取语义信息困难,语义级检索的研究难度大、进展缓慢。
