X射线探测器是X射线成像系统的关键部件之一,对成像质量具有决定性作用。然而,随着探测器像素尺寸微缩化、阵列规模指数级扩张,传统探测器面临数据传输带宽受限、功耗激增和信号延迟累积等挑战。因此,在探测器源端引入人工智能(AI)技术...X射线探测器是X射线成像系统的关键部件之一,对成像质量具有决定性作用。然而,随着探测器像素尺寸微缩化、阵列规模指数级扩张,传统探测器面临数据传输带宽受限、功耗激增和信号延迟累积等挑战。因此,在探测器源端引入人工智能(AI)技术成为必然趋势。基于此,系统综述面向智能X射线成像探测器的感算融合架构及实现技术最新进展。首先,剖析光子计数型读出专用集成电路(Application Specific Integrated Circuit,ASIC)在架构优化与能效提升方面的技术突破;其次,探讨通过模拟神经网络实现源端信号实时处理的感内计算技术路径;最后,从算法-电路协同设计角度分析存算一体技术在突破冯·诺依曼架构瓶颈中的创新实践,为构建高能效、低延迟的智能化X射线探测系统提供理论支撑与技术路线。展开更多
Routing is a challenging task in Wireless Sensor Networks (WSNs) due to the limitation in energy and hardware capabilities in WSN nodes. This challenge prompted researchers to develop routing protocols that satisfy WS...Routing is a challenging task in Wireless Sensor Networks (WSNs) due to the limitation in energy and hardware capabilities in WSN nodes. This challenge prompted researchers to develop routing protocols that satisfy WSNs needs. The main design objectives are reliable delivery, low energy consumption, and prolonging network lifetime. In WSNs, routing is based on local information among neighboring nodes. Routing decisions are made locally;each node will select the next hop without any clue about the other nodes on the path. Although a full knowledge about the network yields better routing, that is not feasible in WSNs due to memory limitation and to the high traffic needed to collect the needed data about all the nodes in the network. As an effort to try to overcome this disadvantage, we are proposing in this paper aware diffusion routing protocol. Aware diffusion follows a semi-holistic approach by collecting data about the available paths and uses these data to enforce healthier paths using machine learning. The data gathering is done by adding a new stage called data collection stage. In this stage, the protocol designer can determine which parameters to collect then use these parameters in enforcing the best path according to certain criteria. In our implementation of this paradigm, we are collecting total energy on the path, lowest energy level on the path, and hop count. Again, the data collected is designer and application specific. The collected data will be used to compare available paths using non-incremental learning, and the outcome will be preferring paths that meet the designer criteria. In our case, healthier and shorter paths are preferred, which will result in less power consumption, higher delivery rate, and longer network life since healthier and fewer nodes will be doing the work.展开更多
A sensitive and selective zinc ion ratiometric fluorescence sensor has been synthesized and characterized. This material displays dual fluorescence. After the material was bonded to a closed-shell metal ion, such as ...A sensitive and selective zinc ion ratiometric fluorescence sensor has been synthesized and characterized. This material displays dual fluorescence. After the material was bonded to a closed-shell metal ion, such as Zn2＋, the recovery of the local excited fluorescence of the material-Zn2＋ complex, largely at the expense of the intramolecular charge transfer fluorescence, is consistent with the difference between selected orbital transitions of the free dye and the metal-chelated complex. For instance, the contribution of the πtpy→πtpy, transition becomes more prominent. This is also consistent with the results of the fluorescence decay behavior, measured via a time-correlated single photon counting setup. In contrast, the corresponding open shell Ni2＋ -bound complex quenches both kinds of photoluminescence, due to spin-orbit coupling.展开更多
文摘X射线探测器是X射线成像系统的关键部件之一,对成像质量具有决定性作用。然而,随着探测器像素尺寸微缩化、阵列规模指数级扩张,传统探测器面临数据传输带宽受限、功耗激增和信号延迟累积等挑战。因此,在探测器源端引入人工智能(AI)技术成为必然趋势。基于此,系统综述面向智能X射线成像探测器的感算融合架构及实现技术最新进展。首先,剖析光子计数型读出专用集成电路(Application Specific Integrated Circuit,ASIC)在架构优化与能效提升方面的技术突破;其次,探讨通过模拟神经网络实现源端信号实时处理的感内计算技术路径;最后,从算法-电路协同设计角度分析存算一体技术在突破冯·诺依曼架构瓶颈中的创新实践,为构建高能效、低延迟的智能化X射线探测系统提供理论支撑与技术路线。
文摘Routing is a challenging task in Wireless Sensor Networks (WSNs) due to the limitation in energy and hardware capabilities in WSN nodes. This challenge prompted researchers to develop routing protocols that satisfy WSNs needs. The main design objectives are reliable delivery, low energy consumption, and prolonging network lifetime. In WSNs, routing is based on local information among neighboring nodes. Routing decisions are made locally;each node will select the next hop without any clue about the other nodes on the path. Although a full knowledge about the network yields better routing, that is not feasible in WSNs due to memory limitation and to the high traffic needed to collect the needed data about all the nodes in the network. As an effort to try to overcome this disadvantage, we are proposing in this paper aware diffusion routing protocol. Aware diffusion follows a semi-holistic approach by collecting data about the available paths and uses these data to enforce healthier paths using machine learning. The data gathering is done by adding a new stage called data collection stage. In this stage, the protocol designer can determine which parameters to collect then use these parameters in enforcing the best path according to certain criteria. In our implementation of this paradigm, we are collecting total energy on the path, lowest energy level on the path, and hop count. Again, the data collected is designer and application specific. The collected data will be used to compare available paths using non-incremental learning, and the outcome will be preferring paths that meet the designer criteria. In our case, healthier and shorter paths are preferred, which will result in less power consumption, higher delivery rate, and longer network life since healthier and fewer nodes will be doing the work.
基金Supported by the National Natural Science Foundation of China(Nos20633070, 20833008)the National Key Basic Research Special Foundation of China(Nos2007CB815202)
文摘A sensitive and selective zinc ion ratiometric fluorescence sensor has been synthesized and characterized. This material displays dual fluorescence. After the material was bonded to a closed-shell metal ion, such as Zn2＋, the recovery of the local excited fluorescence of the material-Zn2＋ complex, largely at the expense of the intramolecular charge transfer fluorescence, is consistent with the difference between selected orbital transitions of the free dye and the metal-chelated complex. For instance, the contribution of the πtpy→πtpy, transition becomes more prominent. This is also consistent with the results of the fluorescence decay behavior, measured via a time-correlated single photon counting setup. In contrast, the corresponding open shell Ni2＋ -bound complex quenches both kinds of photoluminescence, due to spin-orbit coupling.
