AN EVALUATION OF ALTERNATIVE SLUDGE TECHNOLOGIES: A SURROGATE WORTH TRADEOFF APPROACH1

ABSTRACT: The surrogate worth tradeoff method is utilized for evaluation of alternative sewage sludge disposal systems for the Boston, Massachusetts, area. The two objectives incorporated into a decision-making framework are net economic benefit and level of environmental impact.     

Vegetation of the Northern Russian Far East in geographic information systems

The cartographic method, in combination with computer technologies and special software, was used to develop a series of projects of geographic information systems (GISs), including regional GISs (RGISs) for three administrative regions (Magadan oblast, Chukchi Autonomous Area, and Koryak Autonomous Area) and the territorial GIS Vegetation of the Northern Russian Far East.     

生物滞留系统处理水产养殖尾水的效能和机制

为探究生物滞留系统(bioretention system,BS)对水产养殖尾水的处理效能,设计并构建倒置(inverted bioretention system,IBS)和正置(control bioretention system,CBS)2组生物滞留系统,在不同进水条件下比较了2种BS构建方式的运行效能,通过胞外聚合物(EPS)、三维荧光光谱和电子传递活性(ETSA)等方法阐述了不同构建方式下BS的脱氮机制。结果表明：在不同进水条件下IBS的处理效能优于CBS,当运行间隔周期为1 d时,IBS的TN和NO₃⁻-N去除率分别达到71.79%~82.00%和68.70%~85.84%,平均去除率比CBS分别高出10.65%和15.89%。CBS和IBS的TN和NO₃⁻-N去除率随进水负荷的增加呈先升高后稳定的趋势,TP波动最小,去除率均稳定在97.04%~99.22%。构建方式对EPS的组分无明显影响,但对EPS含量和ETSA影响显著。IBS的构建方式可促进微生物分泌更多的EPS,其中EPS的多糖(PS)和蛋白质(PN)含量分别比CBS高出66.89 ug·g⁻¹和603.24 ug·g⁻¹,并且IBS的酪氨酸、色氨酸和微生物代谢产物明显高于CBS;此外,与CBS的ETSA为(0.47±0.07) ug·(g·min)⁻¹,相比IBS提高了0.35 ug·(g·min)⁻¹。以上研究结果为应用生物滞留系统技术处理养殖尾水提供参考。     

A framework for definition of logical scenarios for safety assurance of automated driving

Abstract

Objective: In order to introduce automated vehicles on public roads, it is necessary to ensure that these vehicles are safe to operate in traffic. One challenge is to prove that all physically possible variations of situations can be handled safely within the operational design domain of the vehicle. A promising approach to handling the set of possible situations is to identify a manageable number of logical scenarios, which provide an abstraction for object properties and behavior within the situations. These can then be transferred into concrete scenarios defining all parameters necessary to reproduce the situation in different test environments.

Methods: This article proposes a framework for defining safety-relevant scenarios based on the potential collision between the subject vehicle and a challenging object, which forces the subject vehicle to depart from its planned course of action to avoid a collision. This allows defining only safety-relevant scenarios, which can directly be related to accident classification. The first criterion for defining a scenario is the area of the subject vehicle with which the object would collide. As a second criterion, 8 different positions around the subject vehicle are considered. To account for other relevant objects in the scenario, factors that influence the challenge for the subject vehicle can be added to the scenario. These are grouped as action constraints, dynamic occlusions, and causal chains.

Results: By applying the proposed systematics, a catalog of base scenarios for a vehicle traveling on controlled-access highways has been generated, which can directly be linked to parameters in accident classification. The catalog serves as a basis for scenario classification within the PEGASUS project.

Conclusions: Defining a limited number of safety-relevant scenarios helps to realize a systematic safety assurance process for automated vehicles. Scenarios are defined based on the point of the potential collision of a challenging object with the subject vehicle and its initial position. This approach allows defining scenarios for different environments and different driving states of the subject vehicle using the same mechanisms. A next step is the generation of logical scenarios for other driving states of the subject vehicle and for other traffic environments.     

基于HFACS的中国特别重大煤矿事故研究

特别重大煤矿事故一直被认为是中国最严重的社会问题之一。本论文的研究目标有两个。首先,分析中国特别重大煤矿事故的致因因素;其次,定量考察事故致因因素间的相互作用关系。基于HFACS模型,在层级层面上,94起特别重大煤矿事故的实证表明:"不安全行为"的发生频率最高;在类别层面上,"监管不力"的发生频率最高;在指标层面上,"对违法行为失察或制止不力"的发生频率最高。借助OR技术,计算得出上一层级对下一层级指标的影响关系,并得到了一系列致因因素间的影响路径,这为遏制和预防特别重大煤矿事故提供了"路线图"。     

The impact of UV treatment on microbial control and DBPs formation in full-scale drinking water systems in northern China

To manage potential microbial risks and meet increasingly strict drinking water health standards,UV treatment has attracted increasing attention for use in drinking water systems in China.However,the effects of UV treatment on microbial control and disinfection byproducts(DBPs) formation in real municipal drinking water systems are poorly understood.Here,we collected water samples from three real drinking water systems in Beijing and Tianjin to investigate the impacts of UV treatment on microbia...     

基于水生生物的湖泊营养类型评价

对乌梁素海的水生生物进行了评价分析。结果表明:乌梁素海浮游动物共有4大类62种,平均生物量为3.75 mg/L,底栖动物11种,隶属3门3纲4科。底栖动物平均生物量为71.7 g/m2,属于富营养类型。     

OPTIMIZING FLOOD CONTROL ALLOCATION FOR A MULTIPURPOSE RESERVOIR1

ABSTRACT. In the last decade much research has been devoted to applying the systems analysis approach to water resources problems. A popular research goal has been determination of the “best” method of operating a multipurpose reservoir. The goal of this study was to derive the economically optimum flood control diagram for a multipurpose reservoir by systems analysis. The technique employed to optimize the flood control diagram was programmed so that the optimization process could be applied to other multipurpose reservoirs. Two computer programs developed at the U.S. Army Corps of Engineers' Hydrologic Engineering Center were utilized with modifications to simulate the operation of Folsom Reservoir in central California. Economic analyses were incorporated along with an optimization technique into the reservoir operations program; and the resultant program was capable of routing a sequence of monthly reservoir inflows, computing benefits for various flood control diagrams (as dictated by the optimization procedure), and selecting the economically optimum flood control diagram. The univariate gradient technique was the optimization procedure employed. The two computer programs are on file at the Hydrologic Engineering Center in Davis, California.     

Conceptual Design of a System for Selecting Appropriate Groundwater Models in Groundwater Protection Programs

/ An effective groundwater protection program requires understanding of water flow and contaminant transport processes in the subsurface. Although many mathematical models have been developed to simulate the processes, few actually are used in groundwater protection programs due to the difficulties in data collection, model selection, and model implementation. This study presents a conceptual design of a GIS-supported model selection system that evaluates available data and mathematical models to facilitate groundwater protection programs. Steady-state groundwater and contaminant transport models applied in isotropic aquifers are placed into four classes to simulate conservative or nonconservative contaminant transports in simple or complex geohydrological conditions. After analyzing specific study objectives, available data, and model requirements, the proposed system selects a class of models that can be used in simulation and recommends any need for additional data collection. This study initiates an effort to integrate GIS, mathematical models, and expert knowledge in one system to promote the application of appropriate groundwater models. The new technology of GIS and digital data-base management makes it possible to develop such a system in practice.KEY WORDS: Groundwater models; Geographic information systems