Secondly , considering the time characteristic of data warehouse , add theory of data evolument , refer the concept of quality factor and optimize the system of quality measure 其次，考虑到数据仓库的时间特性，加入了数据演化的理论，提出了质量因子的概念，对质量评价体系进行了优化。
In time , information security " demonstrate the property of the existence of information in differefit states and time as well as the different life cycle stages of the information system 从时间上讲信息安全表现为信息存在的不同的状态和时间特性以及信息系统设施存在的不同生命期阶段特性。
Based on lots of on - the - spot investigations and surveys , this thesis studies the characteristics of domestic tourist flows and residents " perception of tourist impacts in coast resorts 本文在大量实地考察、问卷调查的基础上，研究了海滨旅游地国内旅游客流的人口学特性、空间特性、时间特性和居民对旅游影响的感知。
In order to improve the efficiency of spatio - temporal data access , spatio - temporal index mechanisms should considers both characteristics of spatial and temporal and combines both access methods of spatial and temporal 时空索引技术是空间索引技术和时间索引技术的结合，它必须兼顾了时空对象的空间特性和时间特性，才能有效地提高时空数据库的存取效率。
The researches of temporal and frequency characteristic of the output radiation field shows that : as in the linear regime , in the nonlinear regime after the field saturation , the current dominates the development of the radiation field 通过对输出辐射场的时间特性和频率特性的分析，我们得到：与线性区域一样，在饱和后的非线性区域，电流对辐射场的非线性演化起着决定性的作用。
For investigating thermal character changing of matter with shock compression , we need to measure the time character of radiating spectrum of matter with shock compression and its temperature , that is to measure transient time - resolved spectrum and its temperature 为了研究冲击加载下物质热特性的变化，需要测量冲击压缩态物质所发射脉冲热辐射光谱及温度的时间特性，即进行瞬态光谱的时间分辨测量及温度解析。
In this paper , the time property of its anode and dynode outputs has been studied and compared by using weak cherenkov light , the results show that their time resolution is dependent on the number of the electrons collected at the same conditions 为了获得多个倍增极的输出信号，对其进行了相应的改进，利用弱契伦科夫光，研究了其阳极和倍增极的时间特性，并作了比较，结果表明相同条件下它们的时间分辨与所收集的电子数有很大关系。
Abstract : the affects of crystal absorption for heat radiation on crystal growth , which include : the heat loss of the hot grower , the chara - cteristic of temperature - time of crystal growth , the pattern of fluid flow and the shape of interface , the interface inversion of crystal , the temperature distribution and the thermal stress distribution , are reviewed in this paper 文摘:本文综述了晶体对熔体热辐射吸收对晶体生长的影响，包括对热腔热耗散的影响；对晶体生长温度时间特性的影响；对液流形态和固液界面形状的影响；对晶体界面反转的影响；对晶体中温度分布和应力分布的影响。
On the base of thorough analysis of fault characters , the petri net model is introduced and changed into fault petri net ( fpn ) that can be used to settle some critical problems such as complicated faults , degradation competition and one cause with multiple consequence according to the characters of fault evolvement and spreading . in order to predicate the remained life of particular machine under special working conditions , an algorithm was also providcd to analyse the timely characters of the fpn . it is demonstrated that the method provided in this paper can simulate the dynamic evolvement process more appropriate than tranditional methods such as fault tree analysis ( fta ) and can predicate the remained life of the particular machine under special working conditions 为此，深入分析了机械设备的故障特性，把以描述离散事件动态系统见长的petri网分析技术引入到机械设备剩余寿命预测领域，并根据故障的演变和传播特点，将petri网加以改造，提出适用于对机械设备复合故障动态演变历程进行仿真的“故障petri网” ，解决了“并发故障” 、 “劣化竞争”和“一因多果”等问题，并给出故障petri网的时间特性分析算法，用于单机具体工况下的剩余寿命预测。
In this paper the train running noise level has been predicted with the theory of point sound source . the sound exposure level of a train set pass , equivalent continuous sound level and maximum sound level of a train set pass has been taken as estimate values , and some kinds of affixation attenuation on the course of noise propagation is considered , then the corresponding visual software has been developed . these make it convenient and precise to predict the noise level 本文从点声源的理论出发，对列车运行噪声进行预测计算，采用一列车通过时的单发暴露声级、时间特性的最大声压级和一定时间内的等效声级等作为噪声评价量，并考虑了噪声传播过程中的各种附加衰减，编制了相应的可视化软件，使噪声预测计算方便、准确。
