Simultaneous hydrological prediction at multiple gauging stations using the NARX network for Kemaman catchment,Terengganu, Malaysia

ABSTRACT

This paper presents a neural network model capable of catchment-wide simultaneous prediction of river stages at multiple gauging stations. Thirteen meteorological parameters are considered in the input, which includes rainfall, temperature, mean relative humidity and evaporation. The NARX model is trained with a representative set of hourly data, with optimal time delay for both the input and output. The network trained using 120-day data is able to produce simulations that are in excellent agreement with field observations. We show that for application with one-step-ahead predictions, the loss in network performance is marginal. Inclusion of additional tidal observations does not improve predictions, suggesting that the river stage stations under consideration are not sensitive to tidal backwater effects despite the claim commonly made.

EDITOR D. Koutsoyiannis ASSOCIATE EDITOR F. Pappenberger     

物流业发展对产业结构优化的实证分析 ——基于空间面板杜宾模型

目前,我国正处于产业结构优化升级和实现经济发展方式转变的关键时期。物流业作为第三产业的重要组成部分,具有有效降低经济运行成本、提高运作效率和促进产业结构升级的作用。文章首先对省域产业结构合理化和产业结构高级化空间依赖性进行了检验。然后,基于我国1997―2010年30个省级面板数据,通过引入因变量空间滞后项和自变量空间滞后项,构建空间面板杜宾模型,从产业结构合理化和产业结构高级化2个方面分析物流业发展对产业结构优化的影响。研究结果表明：我国产业结构合理化和产业结构高级化存在着显著为正的空间溢出效应,东部、中部和西部地区存在着明显的空间差异;物流业的发展不仅能够显著促进当地产业结构合理化和产业结构高级化进程,而且对邻近地区产业结构优化具有正向的空间溢出效应。最后,文章有针对性地提出了政策建议。     

Bedload transport measurements with impact plate geophones: comparison of sensor calibration in different gravel‐bed streams

Indirect bedload transport measurements have been made with the Swiss plate geophone system in five gravel‐bed mountain streams. These geophone sensors record the motion of bedload particles transported over a steel plate mounted flush with the channel bed. To calibrate the geophone system, direct bedload transport measurements were undertaken simultaneously. At the Erlenbach in Switzerland, a moving‐basket sampler was used. At the Fischbach and Ruetz streams in Austria, a Helley–Smith type bedload sampler provided the calibration measurements. A Bunte‐type bedload trap was used at the Rofenache stream in Austria. At the Nahal Eshtemoa in Israel, Reid‐type slot bedload samplers were used. To characterize the response of the geophone signal to bedload particles impacting on the plate, geophone summary values were calculated from the raw signal and stored at one second intervals. The number of impulses, i.e. the number of peaks above a pre‐defined threshold value of the geophone output signal, correlated well with field measured gravel transport loads and was found to be a robust parameter. The relations of impulses to gravel transport loads were generally near‐linear, but the steepness of the calibration relations differed from site to site. By comparing the calibration measurements from the different field sites and utilizing insights gained during preliminary flume experiments, it has been possible to identify the main factors that are responsible for site specific differences in the calibration coefficient. The analysis of these calibration measurements indicates that the geophone signal also contains some information about the grain size distribution of bedload. Copyright © 2013 John Wiley & Sons, Ltd.     

Bedload hysteresis in a glacier‐fed mountain river

Sediment transport during flood events often reveals hysteretic patterns because flow discharge can peak before (counterclockwise hysteresis) or after (clockwise hysteresis) the peak of bedload. Hysteresis in sediment transport has been used in the literature to infer the degree of sediment availability. Counterclockwise and clockwise hysteresis have been in fact interpreted as limited and unlimited sediment supply conditions, respectively. Hysteresis has been mainly explored for the case of suspended sediment transport, but it was rarely reported for bedload transport in mountain streams. This work focuses on the temporal variability of bedload transport in an alpine catchment (Saldur basin, 18.6 km², Italian Alps) where bedload transport was monitored by means of an acoustic pipe sensor which detects the acoustic vibrations induced by particles hitting a 0.5m‐long steel pipe. Runoff dynamics are dominated by snowmelt in late spring/early summer, mostly by glacier melt in late summer/early autumn, and by a combination of the snow and glacier melt in mid‐summer. The results indicate that hysteretic patterns during daily discharge fluctuations are predominantly clockwise during the snowmelt period, likely due to the ready availability of unpacked sediments within the channel or through bank erosion in the lower part of the basin. On the contrary, counterclockwise hysteresis tend to be more frequent during late glacier melting period, possibly due to the time lag needed for sediment provided by the glacial and peri‐glacial area to be transported to the monitoring section. However, intense rainfall events occurring during the glacier melt period generated predominantly clockwise hysteresis, thus indicating the activation of different sediment sources. These results indicate that runoff generation processes play a crucial role on sediment supply and temporal availability in mountain streams. Copyright © 2014 John Wiley & Sons, Ltd.     

测角网间接平差中近似坐标自动概算算法设计

在对测角网进行平差计算时,网中未知点平面坐标的概算是一个关键问题。针对测角网的特点,设计了测角网近似坐标自动概算的算法,用实例验证了算法的正确性及可靠性,避免了繁琐的手工近似计算过程,提高了数据处理的效率。     

Defense by association: Sponge‐eating fishes alter the small‐scale distribution of Caribbean reef sponges

Recent studies have demonstrated that sponge‐eating fishes alter the community of sponges on coral reefs across the Caribbean. Sponge species that lack chemical defenses but grow or reproduce faster than defended species are more abundant on reefs where sponge‐eating fishes have been removed by overfishing. Does predator‐removal have an effect on the distribution of sponges at smaller spatial scales? We conducted transect surveys of sponge species that are palatable to sponge predators in proximity to refuge organisms that are chemically or physically defended (fire coral, gorgonians, hard corals) on the heavily overfished reefs of Bocas del Toro, Panama, and a reef in the Florida Keys where sponge‐eating fishes are abundant. In Panama, palatable sponge species were not distributed in close association with refuge organisms, while in the Florida Keys, palatable sponge species were strongly associated with refuge organisms. The presence of fish predators alters the meter‐scale pattern of sponge distribution, and defense by association enhances biodiversity by allowing palatable sponges to persist on reefs where sponge‐eating fishes are abundant.     

基于投入产出模型的大型活动对举办地的经济影响——以广交会为例

事件活动的经济影响评估是国外近20 年来的研究热点,然而近年来遭到很多质疑和争论,国内在该领域的理论和实证研究仍处于起步阶段。一年两届的广交会对举办城市具有持续的深远影响,是城市大型活动的典范。本研究以104 与105 届广交会为案例,采用问卷调查及深度访谈法收集广交会所有参与者的消费支出与结构,并运用投入产出模型评估广交会对广州市间接经济影响。结论表明城市定期举办的大型商务活动对举办地的许多产业部门具有很强的拉动效应,对当地经济产生明显的持续性的经济效应;一届广交会对广州市的直接与间接效应合计163.24 亿元,其中直接经济效应55.26 亿元,间接经济效应为107.98 亿元,直接与间接效应之比为1:1.95;2008 年104 届广交会的直接与间接效应总和占广州市全年GDP的1.98%;参与者对广州的经济拉动作用依次为采购商、参展企业、参展个人、承办方、交易团。此外,本文还特别就研究结论存有高估或低估倾向进行了探究。     

间接ELISA技术在病原性鳗弧菌SMP1快速检测中的应用

以大菱鲆(Scophthalmus maximus)出血症的病原菌——鳗弧菌(Vibrio anguillarum)SMP1为抗原,制备兔抗血清,测定了抗血清的工作浓度和对抗原的特异性,建立了在大菱鲆肝肾组织中检测SMP1的间接ELISA方法。SMP1人工感染大菱鲆,用建立的间接ELISA对大菱鲆肾脏和肝脏进行检测,结果肾脏的阳性检出率为87.7%,肝脏的阳性检出率为90%。该方法的建立有助于快速准确地鉴定由SMP1引起的大菱鲆疾病。     

数字化地形图对象的几何约束和平差

主要对数字化地形图对象进行几何约束平差.以房屋为例进行了直角纠正,并通过VB的程序设计来实现.     

基于投入产出方法的气象服务综合经济效益评估

如何评估气象服务带来的综合经济效益,一直是人们关注的重点和难点.以投入产出表的分配系数、消耗系数和列昂捷夫逆矩阵为核心,提出了关联经济效益、间接经济效益和完全经济效益的概念和算法,并以深圳市2012年的气象服务为例对方法进行验证,得到了一系列富于启示意义的结论.如:1)由于产业经济系统内部的关联性,气象服务带来的关联经济效益、间接经济效益和完全经济效益值较大,应引起全社会的关注和重视;2)深圳市气象服务的投入与完全经济效益比值区间约为1:134.34~1:228.378,远大于以往研究1:30~1:51的结果;3)传统的气象服务对象如农林牧渔业、建筑业等带来服务经济效益偏低,未来应重视向研究与试验发展业,综合技术服务业,租赁和商务服务业,居民服务和其他服务业,信息传输、计算机服务和软件业等服务产业提供气象服务,提高气象服务给社会带来的综合经济效益.