基于微机电系统(Micro-Electro-Mechanical System,MEMS)技术研制的MEMS强震仪具有易集成、维护成本低和低功耗等优点,在地震监测领域应用广泛.然而,MEMS强震仪集成的软、硬件资源有限,并且受仪器自身噪声等因素干扰较大,地震信号测量...基于微机电系统(Micro-Electro-Mechanical System,MEMS)技术研制的MEMS强震仪具有易集成、维护成本低和低功耗等优点,在地震监测领域应用广泛.然而,MEMS强震仪集成的软、硬件资源有限,并且受仪器自身噪声等因素干扰较大,地震信号测量结果质量较低,对嵌入算法要求更高.针对这一问题,本文提出一种更适用于MEMS强震仪的改进长短时窗均值比(Short Term Average/Long Term Average,STA/LTA)算法.首先,通过构建抗干扰(Anti-interference,AR)特征函数抑制基线漂移和低频噪声的干扰,提高STA/LTA算法拾取地震事件的抗干扰能力;其次,提出采用“延时长窗”的方式,提高STA/LTA算法的计算效率和拾取精度,减少STA/LTA算法对MEMS集成资源的占用;最后,结合时窗位置进一步探究不同时窗大小对STA/LTA算法拾取效率的影响.实际地震资料处理结果表明,本文提出的改进STA/LTA算法计算效率更高,实时性和抗干扰能力更强,更适用于集成资源有限的MEMS强震仪.展开更多
With the recent development of digital Micro Electro Mechanical System （MEMS） sensors, the cost of monitoring and detecting seismic events in real time can be greatly reduced. Ability of MEMS accelerograph to record...With the recent development of digital Micro Electro Mechanical System （MEMS） sensors, the cost of monitoring and detecting seismic events in real time can be greatly reduced. Ability of MEMS accelerograph to record a seismic event depends upon the efficiency of triggering algorithm, apart from the sensor＇s sensitivity. There are several classic triggering algorithms developed to detect seismic events, ranging from basic amplitude threshold to more sophisticated pattern recognition. Algorithms based on STA/LTA are reported to be computationally efficient for real time monitoring. In this paper, we analyzed several STA/LTA algorithms to check their efficiency and suitability using data obtained from the Quake Catcher Network （network of MEMS accelerometer stations）. We found that most of the STA/LTA algorithms are suitable for use with MEMS accelerometer data to accurately detect seismic events. However, the efficiency of any particular algorithm is found to be dependent on the parameter set used （i.e., window width of STA, LTA and threshold level）.展开更多
To reduce the potential signaling traffic in IP multimedia subsystem （IMS）, the session establishment procedures were investigated. The serving call session eontrol function （S-CSCF） is the major bottleneck in IMS...To reduce the potential signaling traffic in IP multimedia subsystem （IMS）, the session establishment procedures were investigated. The serving call session eontrol function （S-CSCF） is the major bottleneck in IMS and the existing 3GPP service triggering algorithm （STA） based on initial filter eriteria （iFC） increases the end-to-end session setup delay remarkably. To reduce the session setup delay and improve the system performanee, a SIP response message based filter criteria （rFC） was proposed. Based on the rFC, a SIP response message based STA （RSTA） was further proposed. The modeling and theoretical analysis of 3GPP STA and RSTA were presented. Simulation results show that, compared with 3GPP STA, the RSTA can avoid the additional signaling traffie load of the S-CSCF and application server （AS） effectively, reduce the session setup delay eonsiderably, increase the throughput of the S-CSCF and improve the quality of service （QoS） of IMS network.展开更多
地震波初至拾取是地震预警、地震定位等地震资料处理工作的重要基础,其实时性和准确性直接影响地震资料处理工作的效率.实际应用中,地震波初至拾取受日益增多的噪声干扰较大,传统地震波初至拾取算法很难兼顾实时性、准确性.针对上述问题...地震波初至拾取是地震预警、地震定位等地震资料处理工作的重要基础,其实时性和准确性直接影响地震资料处理工作的效率.实际应用中,地震波初至拾取受日益增多的噪声干扰较大,传统地震波初至拾取算法很难兼顾实时性、准确性.针对上述问题,本文提出一种基于Delaunay三角(简称为D三角)剖分的天然地震波初至实时拾取算法.首先,本文对STA/LTA-AIC(Short-Term Average/Long-Term Average-Akaike Information Criterion)算法特征函数进行参数分析,引用包含平方项和差分项的特征函数,增强算法的实时性;其次,通过改进时窗位置并加入取消时窗的方式,增加算法抗短时强噪声干扰的能力;最后,考虑到地震波在两台站间的最快传播速度,由台间距和地震波最大走时设置走时残差阈值,并依据D三角关系,提出D三角触发判别准则剔除部分干扰噪声.川渝地区现场数据验证表明,本文改进的STA/LTA-AIC算法提高了单台拾取地震波初至的抗短时强噪声能力,基于D三角剖分的天然地震波初至拾取算法能排除各台站误拾取信号,实时、准确、可靠拾取出实际地震波初至时刻.展开更多
文摘基于微机电系统(Micro-Electro-Mechanical System,MEMS)技术研制的MEMS强震仪具有易集成、维护成本低和低功耗等优点,在地震监测领域应用广泛.然而,MEMS强震仪集成的软、硬件资源有限,并且受仪器自身噪声等因素干扰较大,地震信号测量结果质量较低,对嵌入算法要求更高.针对这一问题,本文提出一种更适用于MEMS强震仪的改进长短时窗均值比(Short Term Average/Long Term Average,STA/LTA)算法.首先,通过构建抗干扰(Anti-interference,AR)特征函数抑制基线漂移和低频噪声的干扰,提高STA/LTA算法拾取地震事件的抗干扰能力;其次,提出采用“延时长窗”的方式,提高STA/LTA算法的计算效率和拾取精度,减少STA/LTA算法对MEMS集成资源的占用;最后,结合时窗位置进一步探究不同时窗大小对STA/LTA算法拾取效率的影响.实际地震资料处理结果表明,本文提出的改进STA/LTA算法计算效率更高,实时性和抗干扰能力更强,更适用于集成资源有限的MEMS强震仪.
基金IIT Roorkee under the Faculty Initiation Grant No.100556
文摘With the recent development of digital Micro Electro Mechanical System （MEMS） sensors, the cost of monitoring and detecting seismic events in real time can be greatly reduced. Ability of MEMS accelerograph to record a seismic event depends upon the efficiency of triggering algorithm, apart from the sensor＇s sensitivity. There are several classic triggering algorithms developed to detect seismic events, ranging from basic amplitude threshold to more sophisticated pattern recognition. Algorithms based on STA/LTA are reported to be computationally efficient for real time monitoring. In this paper, we analyzed several STA/LTA algorithms to check their efficiency and suitability using data obtained from the Quake Catcher Network （network of MEMS accelerometer stations）. We found that most of the STA/LTA algorithms are suitable for use with MEMS accelerometer data to accurately detect seismic events. However, the efficiency of any particular algorithm is found to be dependent on the parameter set used （i.e., window width of STA, LTA and threshold level）.
基金Supported by National Science Fund for Distinguished Young Scholars (No. 60525110)National Basic Research Program of China (No.2007CB307100, 2007CB307103)+1 种基金Program for New Century Excellent Talents in University (No. NCET-04-0111 )Development Fund Project for Electronic and Information Industry (Mobile Service and Application System Based on 3G)
文摘To reduce the potential signaling traffic in IP multimedia subsystem （IMS）, the session establishment procedures were investigated. The serving call session eontrol function （S-CSCF） is the major bottleneck in IMS and the existing 3GPP service triggering algorithm （STA） based on initial filter eriteria （iFC） increases the end-to-end session setup delay remarkably. To reduce the session setup delay and improve the system performanee, a SIP response message based filter criteria （rFC） was proposed. Based on the rFC, a SIP response message based STA （RSTA） was further proposed. The modeling and theoretical analysis of 3GPP STA and RSTA were presented. Simulation results show that, compared with 3GPP STA, the RSTA can avoid the additional signaling traffie load of the S-CSCF and application server （AS） effectively, reduce the session setup delay eonsiderably, increase the throughput of the S-CSCF and improve the quality of service （QoS） of IMS network.
文摘地震波初至拾取是地震预警、地震定位等地震资料处理工作的重要基础,其实时性和准确性直接影响地震资料处理工作的效率.实际应用中,地震波初至拾取受日益增多的噪声干扰较大,传统地震波初至拾取算法很难兼顾实时性、准确性.针对上述问题,本文提出一种基于Delaunay三角(简称为D三角)剖分的天然地震波初至实时拾取算法.首先,本文对STA/LTA-AIC(Short-Term Average/Long-Term Average-Akaike Information Criterion)算法特征函数进行参数分析,引用包含平方项和差分项的特征函数,增强算法的实时性;其次,通过改进时窗位置并加入取消时窗的方式,增加算法抗短时强噪声干扰的能力;最后,考虑到地震波在两台站间的最快传播速度,由台间距和地震波最大走时设置走时残差阈值,并依据D三角关系,提出D三角触发判别准则剔除部分干扰噪声.川渝地区现场数据验证表明,本文改进的STA/LTA-AIC算法提高了单台拾取地震波初至的抗短时强噪声能力,基于D三角剖分的天然地震波初至拾取算法能排除各台站误拾取信号,实时、准确、可靠拾取出实际地震波初至时刻.
