基于SWMM模型模拟的海绵城市建设效果评估——以北京市房山区为例

为定量评估房山区现状海绵建设情况,支撑2020年海绵城市达标考核工作,采用资料收集结合现场调研的方式获取各类海绵建设项目信息并进行校核,借助ArcGIS软件将海绵设施数字化,并以排水分区为单元完成落图.基于暴雨径流管理模型SWMM软件构建全区数值模型,将调研的海绵设施概化到模型中开展模拟评估.结果表明:截至2020年底,房山全区有效海绵项目418个,主要分布在拱辰及西潞街道、长阳镇、良乡镇、窦店镇、阎村镇、城关街道及燕山地区.模拟结果表明城市建成区达标面积为13.73 km2,达标比例20.46％.本项目研究方法可为全市其他区的海绵现状评估提供参考.     

基于GRACE的京津冀地下水储量变化

基于2003—2019年GRACE陆地水储量变化数据和全球陆地水文模型（global land data assimilation system,GLDAS）数据反演京津冀地下水储量变化,运用时空分析方法对地下水等效水高变化进行时空演变特征分析。在空间变化上,整个京津冀地下水等效水高变化速率约为-51.77 mm/a,其中：北京市变化速率最低,约为-38.15 mm/a;天津市变化速率最高,约为-62.85 mm/a;河北省变化速率与区域平均变化水平相当,约为-52.42 mm/a。基于Sen Slope和Mann-Kendall非参数检验法分析得出西部、西南部和中部地区地下水等效水高下降[JP]趋势最明显,东北部下降趋势最小。在时间变化上,地下水等效水高变化具有一定的季节性规律：夏季变化速率最大,约为-75.99 mm/a;冬季变化速率最小,约为-37.24 mm/a;春秋两季的变化速率大致相同,分别为-52.34 mm/a和-48.21 mm/a。在影响因素分析中,人类活动是引起京津冀地区地下水等效水高变化的主要因素。研究结果可为科学掌握京津冀地下水储量时空变化规律提供数据支撑。     

A novel dual-biological-community swarm intelligence algorithm with a commensal evolution strategy for multimodal problems

The Journal of Supercomputing - For sophisticated applications, engineers should always consider multi-objective, multi-task or multi-modal problems, especially in the Internet of Things, such as...     

Anomaly detection via a combination model in time series data

Since the time series data have the characteristics of a large amount of data and non-stationarity, we usually cannot obtain a satisfactory result by a single-model-based method to detect anomalies in time series data. To overcome this problem, in this paper, a combination-model-based approach is proposed by combining a similarity-measurement-based method and a model-based method for anomaly detection. First, the process of data representation is performed to generate a new data form to arrive at the purpose of reducing data volume. Furthermore, due to the anomalies being generally caused by changes in amplitude and shape, we take both the original time series data and their amplitude change data into consideration of the process of data representation to capture the shape and morphological features. Then, the results of data representation are employed to establish a model for anomaly detection. Compared with the state-of-the-art methods, experimental studies on a large number of datasets show that the proposed method can significantly improve the performance of anomaly detection with higher data anomaly resolution.

     

果园数据采集和监控的低功耗节点设计

针对果园种植密度大、障碍物多使得通信受阻的缺点,设计了一种适合果园数据采集和监控的低成本、低功耗的传感器节点;节点的微控制器采用低功耗ATmega128L,射频模块采用CC2420,并采用SHT11空气温湿度传感器、ISL29010光照传感器、FDS-100土壤水分传感器、Pt1000土壤温度传感器作为传感器模块,对节点的软件进行了详细设计,改进了操作系统任务调度方法,通过引入休眠机制设计了MAC层和网络层通信协议;通过将文中节点应用于南通海安市的大公镇果园试验基地,结果表明:文中设计的节点在采样周期为1 050 s时,能正常工作116天,具有低功耗和生命周期长的优点,同时其采样湿度的平均误差仅为0.213％,具有数据采集精度高的优点,能满足果园信息采集和监控的要求.     

基于I~2C总线的AD7745控制与读取方法

AD7745是一种响应快速兼超低功耗的高精度电容数字转换器,其采用的通信总线I2C是一种简单双向的两线制同步串行总线,它只需要一根数据线和一根时钟线即可实现连接器件之间的数据传送,但目前广泛应用的51系列单片机均不具有这种接口;文章详细研究了AD7745芯片内部的测量原理及寄存器配置方式,设计了其与单片机的硬件连接电路,使用STC89C52RC单片机的两条普通I/O线,通过软件编程模拟I2C总线所要求的操作时序,实现了对AD7745的控制与数据读取;同时,给出了其中关键程序,调试结果证明了该系统的有效性与稳定性。     

基于云自适应遗传算法的NoC路径分配研究

路径分配是NoC设计流程中的两个关键步骤之一;路径分配的结果对NoC系统的性能尤其是通讯延时有着很重要的影响;多约束条件下的NoC路径分配问题是NP完全问题,要求出其最优解比较困难,目前常用的方法是利用启发式算法求得其较优解;文中提出一种基于云自适应遗传算法的NoC路径分配解决方案,该算法利用云模型对传统遗传算法加以改进,采取新的方法自动调整遗传算法过程中的交叉概率pc和变异概率pm,将适应度与云模型的3个参数Ex、En、He相互结合,从而达到优化遗传算法的目的;将此算法应用于2D-Mesh拓扑结构的NoC中,以平衡链路负载和联合优化为实验目标,以优化静态通讯分配结果;实验证明,文章所采取的算法在平衡链路负载和联合优化方面均取得了良好的效果。     

遗传算法模糊PID测控系统在环控试验台中的应用

飞机环控试验台须模拟流量0～14000kg/h、压力0～2.5MPa和常温～500℃的空气环境;项目要求测控范围广、精度±1%且不超调;空气状态具有非线性、时变等特点,且控制参数之间存在复杂耦合;针对以上难点,设计了分布式测控系统,提出了改进的智能PID控制方案;通过遗传算法分段整定PID参数,离线建立PID数据库,使系统能够根据控制目标值选择最优PID初值;在此基础上,结合模糊推理在线调整PID参数,使系统具有了自适应性,能在具体工况和干扰下达到很好的控制效果;实际应用中完全满足了指标要求,解决了传统PID的控制难点,对类似的复杂系统有一定借鉴意义。     

Enterprise architecture,IT effectiveness and the mediating role of IT alignment in US hospitals

Despite the possible benefits of implementing healthcare information technologies, successful implementation of effective healthcare information technology is constrained by cultural and regulatory concerns and technical obstacles encountered when establishing or upgrading an organisation's enterprise infrastructure. In this paper, we advance Ross' four‐stage model of enterprise architecture maturity as a valuable IT resource for helping healthcare organisations sustain a competitive advantage. We use partial least squares (PLS) structural equation modelling to analyse survey data from 164 US hospitals at different stages of EA maturity. Our results provide evidence that enterprise architecture maturity directly influences the effectiveness of hospitals' IT resources for achieving strategic goals. Further, enterprise architecture maturity indirectly influences the effectiveness of IT resources when IT alignment is incorporated as a mediating variable. We discuss the implications of our findings for research and practice and suggest opportunities for future research.