基于数据库的PMP估算软件系统开发及应用

任何水工建筑物的修建都需要根据一定大小的洪水作为标准来进行设计,水文气象法是计算设计洪水的途径之一,它是将PMP转化为PMF,从而得到所需要的洪水。在推求PMP时需要用到水文气象数据,而传统的水文数据通常以年鉴的形式刊印、存储的,数据难获得且不易查询。数据库是将数据按照一定的数据模型进行组织、描述和存储,数据库中的数据是为众多用户所共享信息而建立的,数据库的数据共享性不仅满足了各用户对信息内容的要求,同时也满足了各用户之间信息通求。本文将数据库技术与PMP估算相结合,利用数据库进行统一的标准计算,避免人为因素的误差,也简化了计算过程。     

Storm环境下基于拓扑结构的任务调度策略

针对Storm流式计算平台中默认轮询调度策略存在通信开销大、负载不均衡的问题,提出基于拓扑结构的任务调度策略（TS²）。首先,选取CPU资源充足且可用的工作节点并各分配一个进程,消除节点内进程间通信开销,优化进程部署;然后,分析拓扑结构,找出拓扑中度最大的组件,优先分配该组件的线程;最后,在满足节点可承载最大线程数的条件下,尽可能将关联任务部署到同一个节点来减少节点间通信开销,改善集群负载均衡,优化线程部署。实验结果表明：在系统延迟方面,与Storm默认调度策略和离线调度策略相比,TS²的平均优化率分别为16.91%和5.69%,有效提高了系统的实时性;在节点间通信开销方面,TS²相比于Storm默认调度策略平均降低了15.75%;在平均吞吐量方面,TS²相比于Storm默认调度策略平均提升了14.21%。     

机器人直赛道赛跑方案和走直线控制策略的设计与实现

提出了用能力风暴机器人进行直赛道赛跑的一种方案。设计了直赛道竞赛台,确定了比赛规则。为了机器人具有快速性和走直线的能力,专门讨论了两轮分别驱动式机器人如何实现走直线的问题。分析和使用了已有走直线控制策略后提出了新的控制策略,所设计控制策略已通过试验验证,验证结果表明新策略比旧策略优越。     

Modeling Storm Water Mass Emissions to the Southern California Bight

Storm water runoff is perceived as a major source of pollutants that results in adverse environmental effects, but large-scale assessments are rarely conducted. The problem is particularly pronounced in southern California where 17 million people have rapidly developed coastal watersheds. The goal of this study was to make regionwide estimates of mass emissions, assess the relative contribution from urbanized watersheds, and compare pollutant flux from different land uses. A geographic information system-based storm water runoff model was used to estimate pollutant mass emissions based on land use, rainfall, runoff volume, and local water-quality information. Local monitoring data were used to derive runoff coefficients; over 1,700 storm water sampling events were used to calibrate and validate annual loadings. An average rainfall year produced 1,073×109?L of runoff, 118,000 metric tons (MT) of suspended solids, 1,940 MT of nitrate-N, 108 MT of zinc, and 15 kg of diazinon. The majority of mass emissions were from urbanized watersheds except for suspended solids, total DDT, and chlorpyrifos. Agricultural areas had the greatest fluxes for pesticides, including total DDT and chlorpyrifos while open areas typically had the smallest.     

吉安市“2010·6”暴雨洪水分析

2010年6月,吉安市发生了大范围的持续暴雨洪水过程,由于本次暴雨洪水的特殊性,曾引发了一系列的洪涝灾害甚至溃堤.本文分析了该次暴雨洪水特性及重现期,有利于掌握该地区暴雨洪水的特点,为防汛减灾提供依据.     

An efficient reliable broadcasting protocol for wireless mobile ad hoc networks

The mobile ad hoc network (MANET) has recently been recognized as an attractive network architecture for wireless communication. Reliable broadcast is an important operation in MANET (e.g., giving orders, searching routes, and notifying important signals). However, using a naive flooding to achieve reliable broadcasting may be very costly, causing a lot of contention, collision, and congestion, to which we refer as the broadcast storm problem. This paper proposes an efficient reliable broadcasting protocol by taking care of the potential broadcast storm problem that could occur in the medium-access level. Existing protocols are either unreliable, or reliable but based on a too costly approach. Our protocol differs from existing protocols by adopting a low-cost broadcast, which does not guarantee reliability, as a basic operation. The reliability is ensured by additional acknowledgement and handshaking. Simulation results do justify the efficiency of the proposed protocol.     

Activated soil filters (bio filters) for the elimination of xenobiotics (micro-pollutants) from storm- and waste waters

A technical scale (0.12 m³) activated soil filter (bio filter) has been used to eliminate diverse xenobiotics (organic micro-pollutants) such as organophosphate flame retardants, and -plasticisers, musk fragrances, DEHP, benzothiazoles and triclosan from water. Model experiments to treat combined sewer overflow, storm water and a post treatment of waste water were performed in controlled laboratory experiments. The indicator compounds were typical for waste water. Diverse chemical compound groups and a wide spectrum from the lipophilic (pK_ow = 5.9) to the hydrophilic (pK_ow = 2.6) were included. The system consisted of a layer with high organic content (with vegetation to prevent clogging), a sand filter and a gravel drainage layer. The organic layer was spiked with activated sludge to enhance biomass and biodegradation potential. Usually the elimination rates varied from 64% to 99%, with only one compound reaching as little as 17%. For a technical suitability assessment it was calculated how long these filters would be stable in eliminating organic compounds from water. The estimated operating times for such systems was found to be about 100 years for a stack height of 2 m a year in regard to most compounds in this study.     

Laboratory Simulation of Urban Runoff and Estimation of Runoff Hydrographs with Experimental Curve Numbers Implemented in USEPA SWMM

The prognostic capabilities of a lumped hydrologic modeling approach may be complicated by routing and connectivity among infiltrative and impervious surfaces. We used artificial rainfall to generate runoff from impervious and bare soil boxes arranged in series to simulate different extents and connectivity of impervious surfaces under different moisture conditions for pervious areas. Curve numbers were calculated from observed rainfall and runoff data, compared with published values, and used in the curve number infiltration algorithm in the U.S. EPA Storm Water Management Model 5 (USEPA SWMM5) to generate runoff hydrographs. Experimental curve numbers were higher than tabular USDA values, ranging from 91 to 96. Simulations of infiltration and runoff response with experimental curve numbers showed overall good agreement with observed data, although SWMM5 was unable to re-create early term infiltration patterns, and simulated runoff lagged observed, which is attributed to implicit accounting for soil moisture and other assumptions of the SWMM5 curve number application. Our results highlight some prospects for the use of curve numbers in modeling infiltration and runoff.     

Hydrodynamic numerical modelling of storm surges — Application to the Bay of Bengal

A hydrodynamic numerical model and a tide-surge interaction model are described for the evaluation of storm surges and their interaction with the tides in the Bay of Bengal. Numerical experiments are performed with the help of these models to simulate the surges generated by three recent severe cyclonic storms which struck the east coast of India and Bangladesh. The predicted peak sea-surface elevations compare well with the limited observed values.     

试论FM立体声广播发射机中锁相调频环路参数对立体声分离度的影响

本文分析了FM立体声广播发射机中锁相调频环路参数与立体声分离度的关系,给出了环路参数的设计原则。