基于改进的热惯通量模型在土壤水反演技术的研究

采用改进的热惯通量模型,结合MODIS遥感数据,对辽西某干旱半干旱区域进行土壤水时空反演分析。分析结果表明:改进的热惯通量模型可解决传统模型无法反演低温期土壤含水量的局限,在土壤水反演精度上明显好于传统模型,相比于传统模型,改进模型模拟值和实测值之间的相对误差Er从30.9%减少到19.8%,均方根误差RMS值从0.057g/cm3降低到0.033g/cm~3。土壤水反演空间变化呈现较为明显的季节性变化特点,这主要是因为地表是反演受地表温度影响较大,地表温度较高的区域,其土壤水含量相对较大,反之,地表温度较低区域,土壤水含量一般较低。     

三角高程测量成果整理中“两差”改正系数C的确定方法

本文讨论了低标(近地面)三角高程测量中如下问题:①三角高程测量成果整理中根据实测(?)合理地确定“两差”改正系数C的必要性;②C的合理确定一法——筛选法;③合理确定的C与测量成果精度的关系。     

基于水利工程GPS控制网布设与测量精度分析

通过论述GPS控制网布设和全站仪三角高程测量方法,分析了高坎子电站测量过程中应遵守的测量限差要求及高程测量、GPS控制网的计算精度;然后对GPS控制网布设于山区水利工程的可靠性进行了验证,同时对四等水准测量精度能够采用全站仪测量的规定进行检验。     

全站仪轴线误差分析与改正计算

针对全站仪的轴线(视准轴、横轴、竖轴)和反光镜轴线固有的几何关系对角度观测和距离观测具有一定的影响,找出变化规律,明确影响程度,并给出相应的补偿和改正方法,为提高全站仪测角、测距的精度提供了理论依据,对生产实践中根据精度要求合理选择补偿和改正选项具有指导意义。     

全球棉花供需状况

①包括巴西,中国(大陆)、哥伦比亚、墨西哥、土耳其和除希腊以外的长期进口商。 ②包括日本、中国(大陆)、香港、韩国、新加坡。 ③包括印度尼西亚、马来西亚、菲律宾、泰国、越南。 ④棉籽绒和损耗,运输过程中重量的改变,不同的记录时期和衡量仪器的误差,都是造成世界进出口值不等的原因。 ⑤计算出来的和实际的库存不同;预计下一季度的总合。 ⑥世界期末库存减去中国(大陆)的库存和中国的深出口除以世界消费减去中国(大陆)消费之差。 ⑦每磅棉花多少美分。     

民用汽车保有量的灰色预测模型研究

一、灰色数列预测模型建立 灰色预测指以GM(1,1)模型为基础所进行的预测。灰色模型有五种:(1)数列预测;(2)灾变与异常值预测;(3)季节灾变与季节异常值预测;(4)拓扑预测;(5)系统预测。本文对汽车保有量的预测采用灰色数列预测。 本文对传统的GM(1,1)模型的建立过程进行了改造,用线性回归来建立GM(1,1)模型,用显著性检验方法代替关联度和后验着进行精度检验和参数识别。     

螺栓连接计算精确度及可靠性的探讨

为了进一步提高螺栓连接设计计算的精确度,本文从强度设计准则、设计规范、基本计算公式等方面作了一些探讨,并着重对以屈服极限为门槛值的强度计算进行了可靠性分析。文中提出了拧紧系数和扳手误差系数是影响螺栓应力离散的重要因素。为了提高计算精度,应将这些因素的影响通过修正系数引入设计计算公式,并在可靠性计算的基础上选择合理的安全系数。     

冰区海上采油平台极端冰载下断裂的可靠性分析

我国渤海每年约有3个多月的结冰期,冰与海上采油平台的相互作用,远较波浪为甚.因此,冰区固定采油平台的设计以及对服役期平台的评估,均需进行可靠性分析,而且主要是极端冰裁作用下断裂的可靠性分析.文章首先建立了考虑温度效应的剩余强度的可靠性计算模型;然后给出了决定构件剩余强度的断裂韧性CTOD值δ_0的不同温度下的概率分布;同时还给出了取决于冰厚及海冰强度的构件上最大应力的概率分布;最后,根据计算模型,文章给出了计算平台构件可靠度的方法,并结合渤海八号平台评估的计算实例,对在役海上采油平台的整体系统,进行了安全可靠性分析.     

基于遗传算法优化ELM模型的小型水利工程沉降预测研究

为找出适用于小型水利工程沉降预测的标准方法,本文基于遗传算法GA优化极限学习机ELM模型、3种不同的ELM激活函数,得到6种计算模型,并根据输入地下水动态、降水量、气温和土质变化情况4项指标的2种输入组合形式,共计12种模型输入,得出最优沉降预测模型,结果表明:GA-ELM_(sin)模型表现出了较高的精度,同时遗传算法可提高ELM模型计算精度,地下水动态是影响沉降的主要因素。     

石家庄市大气颗粒物TSP，PM10和PM2.5主要成分研究

为了研究石家庄市大气颗粒物TSP,PM_(10)以及PM_(2.5)中的主要成分,在不同季节分别采集了该市6个点位的颗粒物样品,对其主要成分的浓度与含量进行了分析。研究表明,TSP,PM_(10)以及PM_(2.5)中的主要成分为SO~(2-)_4,NO~-_3,NH~+_4,Al,Si,Fe,OC,EC等,这些主要成分在各粒径中呈现季节性变化的特点。春季以扬尘污染为主,冬季燃煤污染显著,夏秋季为复合型污染。市区6个点位主要成分的变化规律基本一致,"西南高教"与"西北水源"的颗粒物污染较为严重,可能与其周围污染源分布有关。     

Comparing FTTH access networks based on P2P and PMP fibre topologies

There is an ongoing discussion in the market which Next Generation Access (NGA) architecture best suits future needs and which investment and cost differences exist. The discussion can be subsumed as P2P vs. GPON, which is somewhat misleading as this article reveals. The discussion is driven by the fact that the high capital cost and the long asset life time of fibre mean that the technology choices made today will dominate the opportunities for telecommunication business of all market players, incumbents, competitors, content providers and business and residential users for many years in the future.The paper analyzes the cost and other differences between Fibre-to-the-Home (FTTH) access network architectures and their related different wholesale approaches by using the well-known and understood steady state approach applied in other NGA analyses in the past. In addition to the steady state analysis a dynamic cost evaluation is included taking into account the different investment behaviour of the FTTH architectures over time. The results describe investment and cost differences between architectures, incumbents and wholesale based competitive operators. The analysis has been performed for different geotypes (clusters) of decreasing population density in a representative European settlement structure.     

Indigenous peoples’ nutrition transition in a right to food perspective

In indigenous communities the nutrition transition characterized by a rapid westernization of diet and lifestyle is associated with rising prevalence of chronic disease. Field work and literature reviews from two different policy environments, Argentina (Jujuy) and Canada (Nunavut), identified factors that add to indigenous peoples’ disease risk. The analytical framework was the emerging human right to adequate food approach to policies and programmes. Indigenous peoples’ chronic disease risk tends to increase as a result of government policies that infringe on indigenous peoples’ livelihoods and territories, undermining their economic system, values and solidarity networks. Policies intended to increase food security, including food aid, may also fuel the nutrition transition. There is a need to explore further the connection between well-intended policies towards indigenous peoples and the development of chronic diseases, and to broaden the understanding of the role that different forms of discrimination play in the westernization of their lifestyles, values and food habits. Food policies that take due account of indigenous peoples’ human rights, including their right to enjoy their culture, may counteract the growth of chronic disease in these communities.     

A strategic skill based model of supplier integration and its effect on supply management performance

Supplier integration is a tool to help organizations gain competitive advantage. Strategic supply management skills and the supply management function's perceived status are hypothesized as antecedents to supplier integration leading to supply management performance. The sample for this study includes 152 executive level supply management professionals. The empirical results suggest that strategic skills and perceived status are essential antecedents to supplier integration and subsequent performance. Further, the relationship between strategic skills and performance is mediated by supplier integration. Results of a dominance analysis also suggest which strategic skills are most likely to explain status integration, and performance. These findings have significant implications for supply management theory and practice.     

面向对象的程序设计

用Ｃ＋ ＋ 语言阐述面向对象程序设计中封装和继承的概念以及在实际中怎样运用这些概念提高程序设计水平。     

Cost allocation of WCDMA and wholesale pricing for mVoIP and data services

This study estimates cost-based prices for wholesale voice and data services provided to 3G (WCDMA) MVNOs according to their distinct types. For estimation, 3G MVNOs are classified into different types, and the overall cost of WCDMA facilities are separated into voice and data components based on their subscriber rates, actual traffic rates, as well as efficiency consideration of traffic rates. The study then calculates cost-based wholesale prices of voice and data services for each of the 3G MVNO types. The result of this study shows that a cost-plus pricing scheme can help achieve the policy goals of the regulator, namely, lowering telecommunications tariffs and facilitating the introduction of new convergent-type services, far more effectively than the current retail-minus pricing scheme. The findings of this study may assist firms in developing business models based on 3G networks and telecom regulators in designing policies related to interconnection, mVoIP, prepaid calls, wholesale services, and network neutrality.     

Collectivism,individualism, and outgroup cooperation in a segmented China

A consistent theme in cross-cultural management research is that collectivists are more cooperative than individualists. We use Hofstede's measure for individualism–collectivism and combine it with an experimental measure of cooperation to test this relationship in China. In contrast to the established paradigm, we find that groups with higher individualistic scores are more cooperative than those groups with higher collectivistic scores. We attribute these results to groups being composed of outgroup members. In addition, we find that subjects from the more developed coastal area are more individualistic and cooperative than are subjects from inland China.

应用CGI技术创建CAI网页计数器

:CGI( Common Gateway Interface)是应用程序与 Web服务器交互的一个标准接口 ,利用该技术可以实现 HTML不具备的交互式主页功能。本文将通过“教育窗”主页的访问 (点击 )计算器的开发应用实例 ,提出了两种使用 CGI技术实现点击计数的方案     

钻井现场H2S气体的探测及防护

在钻井生产过程中，实施HSE管理体系，预防和控制H2S，保护每一位员工不受H2S气体危害，是钻井生产过程中HSE工作的重要一环。阐述了有害气体H2S的物理特性、毒性标准，介绍了几种常用的H2S气体探测器，以及具体操作方法。     

电子产品的电磁兼容性设计

首先介绍电磁兼容性的基本概念与研究领域,然后重点阐述电子产品的电磁兼容性设计与测量。     

SPYRO在烯烃原料生产方案测算中的应用

文章对SPYRO裂解模拟软件在石化企业烯烃生产原料优化方案测算中的应用进行了比较深度的概括分析.结合该软件在上海石化的实际应用,认为在劣质化原油加工份额不断增加的趋势下,SPYRO裂解模拟软件有助于石化企业在烯烃生产原料优化选择、生产计划合理安排、原油加工生产效益比较等方面为企业相关决策者提供有效地帮助.