A-posteriori analysis of the relevance of a multicriteria decision-aid method for best management practice choice in urban storm drainage

The problem of the choice of best storm drainage management scenarios led to the development of a multicriteria decision-aid method based on twenty seven criteria defined in partnership with a group of experts. A validation study of the methodology showed its relevance on real cases but also that the large number of criteria hindered its use. An a-posteriori analysis of the results obtained by our methodology from three real projects was carried out in order to try to extract non-discriminating criteria, to identify those that could be removed, combined or re-formulated, and to try to understand the reasons why they failed to prove relevant. The work is based on two reduction methods: one empirical and one based on entropy calculations.     

烟台广电中心C60高抛自密实混凝土配比与施工技术

烟台广电中心大楼钢管柱采用C60高抛自密实混凝土。通过对3套材料方案的适配及优化分析,最终选用三菱P.I42.5R水泥,并确定了混凝土的水胶比0.31和矿物掺和料的掺量25%。结合现场高抛模拟试验中对混凝土强度、坍落度、扩展度等的研究,指出配制的混凝土能够满足设计和施工要求。混凝土施工过程中采用小铁锤敲击柱身和钻芯取样的检测方法,对混凝土强度、密实度等进行检测,均符合要求。     

证券分析系统在数字有线电视机顶盒中的实现

简要介绍了基于DVB的数据广播和一个实用的证券分析系统在数字有线电视机顶盒中的实现.     

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.     

日本广播电视的新动向

本文介绍了日本广播电视的发展动向!并且简要集中地介绍了日本HDTV及EDTV两种新的电视广播形式。     

基于水体自然净化的北京奥林匹克公园中心区雨水利用技术

通过设计北京奥林匹克公园中心区雨水利用系统,对雨水回收利用技术进行了大量的研究和技术攻关,在确保排水通畅的前提下,提出了"水体自然净化的雨水利用"设计新理念.将透水铺装区域、绿地、水系等各类用地统盘考虑,通过透水砖、露骨料透水混凝土、增渗设施等新型透水材料,利用透水铺装和渗滤沟内的砂砾料和增渗设施净化雨水.在收集雨水过程中,实现对水质进一步净化,使收集的水质满足灌溉、水景、回灌地下的相关标准,节省了成本,建成了高标准的公园雨水利用系统,对兑现"绿色奥运"承诺和北京的水资源的循环利用具有重要意义.     

Influence of Loss Model on Design Discharge of Homogeneous Plane

By applying the kinematic wave method to a homogeneous, rectangular overland plane, the influence of the constant and proportional-loss models on the design discharge are examined. The examination shows that with the use of the proportional-loss model, there is no partial-area effect and the design discharge is governed by the full-area contribution. On the other hand, with the use of the constant-loss model, there is no partial-area effect if the loss rate is small. For larger loss rates, there is a partial-area effect; and for this case, the design is complicated, since there is a need to search for the critical storm that governs the partial-area effect. The characteristic of the critical storm is that its rate of decrease in rainfall intensity with duration equals the corresponding rate of increase in the contributing area. The preceding findings are consistent with the design concept in the rational method that uses the proportional-loss model, and the results from earlier studies that used the constant-loss model.     

Byzantine Agreement Given Partial Broadcast

This paper considers unconditionally secure protocols for reliable broadcast among a set of n players, where up to t of the players can be corrupted by a (Byzantine) adversary but the remaining h = n - t players remain honest. In the standard model with a complete, synchronous network of bilateral authenticated communication channels among the players, broadcast is achievable if and only if 2n/h < 3. We show that, by extending this model by the existence of partial broadcast channels among subsets of b players, global broadcast can be achieved if and only if the number h of honest players satisfies 2n/h < b + 1. Achievability is demonstrated by protocols with communication and computation complexities polynomial in the size of the network, i.e., in the number of partial broadcast channels. A respective characterization for the related consensus problem is also given.     

Exact and general FT1 penultimate distributions of extreme wind speeds drawn from tail-equivalent Weibull parents

We present a contribution to the current debate on methodologies for assessing extreme wind speeds. We review long-established extreme theory in the light of recent developments and show that it is unnecessary, indeed inappropriate, to resort to asymptotic models. We develop Cramér's method for the general penultimate distribution of extremes for the case of Weibull parents into a new model for extreme wind speeds that avoids the issues of asymptotic convergence and the associated errors. We demonstrate that the 30-year record of hourly mean wind speed at Boscombe Down, UK, has right-tail equivalence to the Weibull distribution and use this record to demonstrate the new model.     

Effect of broadcast and precise ephemerides on estimates of the frequency stability of GPS Navstar clocks

Frequency stability analysis of on-orbit Navstar clocks is performed by the Naval Research Laboratory using both the broadcast and the precise post-processed ephemerides. The phase offset between the Navstar clock and the reference clock is computed from pseudorange measurements obtained by dual-frequency GPS receivers at the five GPS monitor sites and at the U.S. Naval Observatory precise-time site. The broadcast ephemerides are generated at the GPS master control station by a Kalman filter using data collected from the five GPS monitor stations. The precise post-processed ephemerides are generated by the Defense Mapping Agency (DMA) using data collected from the GPS monitor sites and from five additional DMA monitor sites. In this paper the frequency stability is estimated for two Navstar caesium clocks–a Block I caesium clock (Navstar 9) and a Block II caesium clock (Navstar 23)–using both the broadcast and the precise ephemerides. A significant improvement in the estimate of the frequency stability of the Block II clocks has been achieved using the precise ephemeris.