Possibilities and problems with the use of models as a communication tool in water resource management

Politicians and policy-makers, as well as modellers, often nurses an expectation that model derived results is an objective source of information that can be used to support decisions. However, several prerequisites have to be dealt with in order to ensure that models can be used as legitimate and efficient tools in water resource management. Based on empirical material from recent studies on the use of models in stakeholder dialogues, mainly focusing on catchment nutrient transport, two central problems are identified: (a) Models are laden with choices and thus depend on assumptions and priorities of modellers. (b) There are several factors that influence ability and willingness of stakeholders (as information recovers) to criticize or accept results of the modelling exercise. Recognized factors likely to influence stakeholders' acceptance of model derived results include issues at stake, stakeholders' ability to criticize model derived information, and their trust in the institutions that have developed or applied the used models. Identified prerequisites for successful use of models in integrated water resource management include: consideration of user relevance, awareness of and preparedness to handle constraints linked to communication of model-based results, transparency of used models and data and of involved uncertainties, mutual respect between experts and stakeholders and between involved stakeholder groups, a robust institutional network, and sufficient time for dialogues. Development and use of strategies for participatory modelling, based on a continuous dialogue between experts and stakeholders is recommended as a way to facilitate that the prerequisites for a successful use of models in water resource management are fulfilled.     

An analytical study on the thermal characteristics of flat-plate and evacuated solar collectors

In this study, we highlighted differences in the standards used in performance tests of solar collectors. We analyzed testing results for different types of solar collectors to determine the effects of the collector area and mass flow rate, which were not necessarily consistent across all tests. Our analysis showed that the factor,F′ (τα), including collector efficiency factor (F′), could be correlated with the flow rate or area regardless of the collector type. Moreover, the collector loss coefficient (F′U _L ) per flow rate or area for an evacuated collector was less that of a flat-plate collector; this was also correlated with the flow rate or area, regardless of the type of evacuated collector. As a result of this analysis, we propose a modified heat loss coefficient that includes the effects of all parameters that can be considered in a performance test and show that this coefficient could better describe the thermal characteristics of various types of solar collectors.     

A Class of POCA Distributions For rapid fading variations

Polydorou and Capsalis [1] pioneered the concept of POCA distribution to study the statistical behavior of the fast fading characteristics in an indoor environment under the assumption of finite number of scatters. In this note, we derive a comprehensive class of formulas for the POCA distribution to help better statistical modeling of the fast fading characteristics. The calculations involve use of several special functions and their properties.     

后工业时代米兰单功能城区更新

在物化的形式上,解释米兰城市发展历史上的单功能城区的改造意义,并由此分析单功能城区更新的经验:单功能城区向混合居住模式的更新是发展方向;城区的功能重新定义对城区发展有重要意义;以新的建设为基础,发展城区自身的特色,做到城市在更新和特色之间的协调。     

川东二叠系生物礁油气藏的地震勘探技术

 生物礁油气藏是一种特殊的岩性油气藏，由于其地质特点的多样性和复杂性，使得生物礁的地震勘探难度很大。本文针对川东地区二叠系生物礁的地质特点和资料情况，以生物礁气藏为研究对象，从已知井井震响应特征分析出发，通过地震反射结构分析、神经网络波形分类处理、地震属性分析、三维可视化解释、多参数地震反演等多项地震特殊处理和解释方法，建立了生物礁和生物礁储层的判别模式，形成了有针对性的地震勘探配套技术。其中以伽马、补偿中子及声波为目标曲线的多参数地震反演技术对于预测和评价生物礁特别有效。     

碱聚二元体系黏度稳定性研究

活性碱NPS2是白色或无色粒状商品,1%溶液pH值为10.考察了由NpS-2和HPAM HTP(分子量2.85×107,水解度22.0%)组成的碱聚二元体系63℃、7.34 s-1下的黏度性能.8.0 g/L NPS-2 1.5 g/L HTP蒸馏水溶液,在63℃、曝气或无氧条件下老化印天,黏度损失分别为91%和25%.在很宽的加量范围考察外加各种阳离子对该二元溶液曝气3小时的黏度的影响,50 mg/L的Ca22 、Mg2 、Ca2 Mg2 (11)和10 mg/L的Fe2 使黏度分别下降66.9%、73.4%、76.3%和87.4%;Ca2 、Mg2 可与NPS-2反应生成沉淀;Fe2 在较低浓度时使黏度升高,较高浓度时使黏度下降.该二元溶液剪切后的黏度,随3000 1/S剪切时间延长(0.5～9.0 min)而下降,静置(4 h)后黏度恢复幅度则大体相同,剪切5 min后黏度随剪切速率增加(1000～5000 1/s)而下降,≥4000 1/s时黏度不再能恢复.含1.5g/L HTP)的二元溶液的黏度随NPS-2浓度的增加(0～15 g/L)而持续下降,不同NPS-2浓度(6.0～12.5 g/L)的二元溶液的黏度随温度升高(30～80℃)大体上呈直线下降.图8参5.     

坐标测量机激光非接触式测头的研制

本文介绍适用子精密大型测试仪器──坐标测量机的激光非接触式测头的研制。该测头采用ＰＳＤ作为敏感元件并采用单片机技术完成对测量数据的处理。     

连铸坯的液芯轧制

研究了连铸坯的液芯轧制，并结合日本川崎永岛厂的实例，证实了连铸坯液芯轧制的可行性，指出了钢锭和连铸坯液芯轧制的区别，及如何制造压应力状态，推导了坯壳应力与轧辊直径压下量，坯壳厚度的关系，并提出了用振摆式轧机实施连铸机液芯轧制的方案。     

A design and analysis of objective function-based unsupervised neural networks for fuzzy clustering

Fuzzy clustering has played an important role in solving many problems. In this paper, we design an unsupervised neural network model based on a fuzzy objective function, called OFUNN. The learning rule for the OFUNN model is a result of the formal derivation by the gradient descent method of a fuzzy objective function. The performance of the cluster analysis algorithm is often evaluated by counting the number of crisp clustering errors. However, the number of clustering errors alone is not a reliable and consistent measure for the performance of clustering, especially in the case of input data with fuzzy boundaries. We introduce two measures to evaluate the performance of the fuzzy clustering algorithm. The clustering results on three data sets, Iris data and two artificial data sets, are analyzed using the proposed measures. They show that OFUNN is very competitive in terms of speed and accuracy compared to the fuzzy c-means algorithm.     

面向对象工程数据库管理系统O2S并发事务模型

Ｏ２Ｓ是我们在ＳＵＮ工作站上开发的一面向对象工程数据库管理。本文针对工程应用域事务的嵌套性，长时性，数据库逻辑分区性和涉及数据量大的四个显著特点，阐述了Ｓ２Ｓ的事务管理模型。对工程域事务的管理，数据库的恢复和封锁技术进行了讨论。