基于SOCP-MKRVM的区域滑坡敏感性分析研究

为了提高相关向量机（RVM）在区域滑坡敏感性评价中的预测能力,提出了基于二阶锥规划的多核相关向量机 (SOCP-MKRVM)预测模型。以四川省低山丘陵区为例,选取了8个滑坡孕灾因子训练RVM预测模型,并分别运用受试者工作特征曲线（ROC）和滑坡点密度2种方法对预测结果进行验证。通过与单核RVM模型的对比分析,结果表明:SOCP-MKRVM模型提高了对区域滑坡敏感性的评价能力,预测精度提高到71.33%,ROC曲线下面积达到0.741,滑坡点密度分布更加合理,两低敏感区之和为0.89个/100 km2,两高敏感区之和为6.54个/100 km2。     

我国餐厅食物浪费现状调查及影响因素分析

当前,伴随着餐饮业高度发展,食物浪费现象也十分严重。以2000—2010年、1960—1999年出生,餐饮消费金额低于3 000元/月的在校学生和工薪阶层为消费群体,在传统餐厅、自助餐、快餐(小吃)就餐场所进行问卷调研,分析不同类型餐厅就餐的食物浪费现状及意识因素。利用Excel、SPSS等软件结合数理统计理论,统计分析消费者食物浪费现状及原因,运用结构方程模型结合计划行为理论,针对消费者食物浪费的行为意愿进行分析及预测,并通过接受者操作特性曲线(receiver operating characteristic,ROC)验证影响消费者意识因素的预测概率模型的拟合效果。结果显示:消费者在不同类型餐厅就餐时,食物浪费程度为传统餐厅>自助餐厅>快餐(小吃),公务活动为消费者食物浪费的主要就餐场合,其主要原因为菜不合胃口、菜品分量大等;相较于女性,男性更易浪费食物;2000—2010年、1990—1999年出生的消费者食物浪费程度较高,随着年龄的增长食物浪费程度呈逐渐下降趋势;结构方程模型的分析和预测发现,个人行为态度和感知行为控制间接影响消费者食物浪费的行为意愿,可通过引导和改善消费者的意识和态度减少食物浪费。研究发现,消费者减少食物浪费的途径包括打包剩餐、选择自我偏爱的食物等,餐厅要积极引导消费者勤俭节约和剩餐打包意识,可通过提供精美礼品、建立会员制等方式减少食物浪费。     

Assessing the relative impacts of the factors affecting MIS adoption process

Micro-irrigation systems (MIS) have been at the forefront of policy-making and social research in exploring determinants that could potentially impact the adoption of MIS technologies in the field to fulfil the basic aim of enhanced agricultural productivity and enriched nutritional quality of the produce with optimal adoption of natural resources. Therefore, this study was undertaken to determine why MIS technologies have not been adopted to the extent anticipated, so that suitable policy schemes, promotional schemes and socio-technical frameworks could be formulated for their enhanced adoption to enhance the socio-economic status of the farming community in the Dahod district of Gujarat State, India. A study of 350 non-MIS (NMIS) and 350 MIS farmers was conducted to identify factors affecting the MIS adoption process. The logit model was fitted using XLSTAT software (XLSTAT 2014.1.04) to the explanatory variables (determinants) of the MIS adoption process. Type III analysis and ANOVA were conducted to test the relative significance of the explanatory variables adopted. It was found that total income had the highest weight (or beta coefficient, i.e. 0.625) followed by total land area (0.546), motor horsepower (0.499), dependency ratio (0.397), and education (0.295) and age of household head (0.207). Furthermore, to assess the efficacy of the logit model, the ROC curve was also developed and the AUC was found to be 0.881, and therefore the model was considered to discriminate well in identifying the factors affecting the MIS adoption process. The study found that higher total income and education level increase the likelihood of MIS adoption and agricultural water management, and therefore special training programmes on installation, as well as repair and maintenance, of MIS systems and agricultural water management can be planned at the institutional/organisation level. The total cultivable area is also one of the important determinants in MIS adoption, and therefore the adoption of MIS schemes should not be restricted to large farmers only, but rather should be extended to both small and marginal farmers.     

Fered-Fenton法处理石化废水反渗透浓水

以Ti金属网为阴极、Ti负载RuO2金属网为阳极,构建Fered-Fenton反应系统,处理石化废水反渗透膜法浓水.考察H2O2浓度、Fe2+浓度、初始pH值和电流密度等因素对废水处理效果的影响,并分析了废水可生化性及污染物降解规律.结果表明,在H2O2浓度为75.0 mmol/L,Fe2+浓度为7.5 mmol/L,初始pH值为3.0,电流密度为5.1 mA/cm2的条件下,反应120 min后废水TOC可由198.2 mg/L降到99.6 mg/L,有机污染物矿化率达到49.7%,BOD5/COD由0.11提高至0.31,废水可生化性明显改善.三维荧光光谱(EEM)分析结果表明,Fered-Fenton法对废水中类蛋白、类富里酸等荧光有机物去除率达到66.7%,该类大分子难降解有机物的氧化降解有利于改善废水可生化性,为进一步的生化处理创造了良好的条件.     

民航旅客行李托运差异化安检设备联合响应研究*

为提高行李托运差异化安检系统安全性,基于安检设备的依赖关系,提出行李托运安检设备联合响应研究;根据旅客风险属性对其托运行李实施差异化安检,利用二维正态分布建立安检设备的响应分布函数,进行安检设备响应值的数据融合;将系统错误率作为评价指标对比设备联合响应与设备独立响应,分析设备之间的相关系数、报警阈值对系统安全性的影响,并借助ROC曲线得到最优设备报警阈值。研究结果表明:在行李托运差异化安检系统中,设备联合响应优于设备独立响应。研究结果可为民航旅客行李托运安检提供设备支持。     

Reliability of Indicators of Decline in Abundance

Abstract: Although there are many indicators of endangerment (i.e., whether populations or species meet criteria that justify conservation action), their reliability has rarely been tested. Such indicators may fail to identify that a population or species meets criteria for conservation action (false negative) or may incorrectly show that such criteria have been met (false positive). To quantify the rate of both types of error for 20 commonly used indicators of declining abundance (threat indicators), we used receiver operating characteristic curves derived from historical (1938–2007) data for 18 sockeye salmon (Oncorhynchus nerka) populations in the Fraser River, British Columbia, Canada. We retrospectively determined each population's yearly status (reflected by change in abundance over time) on the basis of each indicator. We then compared that population's status in a given year with the status in subsequent years (determined by the magnitude of decline in abundance across those years). For each sockeye population, we calculated how often each indicator of past status matched subsequent status. No single threat indicator provided error‐free estimates of status, but indicators that reflected the extent (i.e., magnitude) of past decline in abundance (through comparison of current abundance with some historical baseline abundance) tended to better reflect status in subsequent years than the rate of decline over the previous 3 generations (a widely used indicator). We recommend that when possible, the reliability of various threat indicators be evaluated with empirical analyses before such indicators are used to determine the need for conservation action. These indicators should include estimates from the entire data set to take into account a historical baseline.     

Integrating probabilistic signed digraph and reliability analysis for alarm signal optimization in chemical plant

The alarm system given in industrial plants are massive and complex. Under such condition, critical alarms are overwhelmed by false and unnecessary alarms and thus result in severe safety issues. To address the problem, this paper proposes a probabilistic signed digraph (PSDG) based alarm signal selection method that requires achieving maximal system reliability. In this method, a PSDG model is firstly constructed to visualize the causal relations between process variables. Then the criteria of observability and identifiability are imposed to determine the candidate alarm variables that can qualitatively distinguish all assumed faults. Instead of selecting the minimum number of combinations of candidate variables, the alarm variables are optimized by a reliability formulation that takes into account the missed alarm and false alarm probabilities of the system; this formulation is solved by the receiver operating characteristic (ROC) graph. Finally, the developed methodology is illustrated using a Tennessee Eastman process.     

Evaluating Ecological Indicators: Lakes In The Northeastern United States

We use data from a survey of several hundred lakes in the northeastern United States by the U.S. Environmental Protection Agency to illustrate an approach to identifying promising indicators of lake condition. We construct a hypothetical gold standard of water quality from the first principal component of 16 chemical variables measured in the lakes, and examine its associations with 71 candidate indicators based on measurements of human activity, birds, fish and zooplankton in the lakes or their watersheds. Nonparametric summaries of these associations – based on rank correlations and receiver-operating-characteristic curves – suggest that variables summarizing the extent of human disturbance are generally the strongest indicators. To the extent that our water-quality variable is a useful proxy for ecological condition, our results suggest that easily-obtained measures of human activity are at least as predictive as many of the harder-to-measure biological indicators that have been proposed.