基于约束熵的复杂系统重要节点崩溃控制研究

为有效控制复杂系统崩溃,提出一种基于约束熵的复杂系统重要节点崩溃控制方法。通过概述现有事故致因理论及模型,建立分析复杂系统安全事故致因的"认知-约束"模型。针对复杂系统节点众多,关联复杂的本质,指出为预防安全事故,必须在强化安全认知能力的基础上对重要节点进行约束控制。在提取节点重要度评估参数后,设计一种改进的复杂系统节点重要度评估算法。最后,引入约束熵概念,构建抑制复杂系统重要节点崩溃的约束熵度量模型。研究结果表明,存在可量化的用于控制复杂系统崩溃的手段;预防安全事故的关键是将适量的约束熵"引入"重要节点。     

The puzzle of North America's Late Pleistocene megafaunal extinction patterns: Test of new explanation yields unexpected results

Although Late Pleistocene extinctions disproportionately affected larger mammalian species, numerous smaller species were also lost. To date, no satisfactory explanation has been presented to account for this pattern. Beginning with the assumption that human predation caused the extinctions, we offer and test the first such explanatory hypothesis, which is predicated on considering more realistic functional response forms (i.e., those that allow for predator interference or prey sharing). We then test the hypothesis via a one-predator, six-prey ecological model that maintains transparency, minimalism of design, and maximal constraint of parameters. Results indicate that altering assumptions about one cornerstone of ecological modeling (i.e., functional response) fails to produce qualitative differences in survival–extinction outcomes—even in conjunction with a wide range of capture efficiency permutations. This unexpected finding suggests that no reasonable form of predation alone is capable of producing the survival–extinction pattern observed. We conclude that the matter of causation and the conclusions of previous Late Pleistocene extinction models remain far less certain than many have assumed.     

经济发达地区水环境约束分区与产业准入研究——以无锡市区为例

随着发达地区经济社会的快速发展,水污染物排放量急剧增加,致使区域水环境不断恶化,并成为制约区域经济社会发展的重要因素。为了协调水环境与经济发展间的关系,许多国家开展水环境功能区划研究,为流域管理和调控提供科学依据,但是这些研究大多以水体为对象,较少关注水陆空间联系以及水环境承载能力对区域产业布局的限制,忽视了经济社会发展对水环境胁迫作用。为此,综合考虑水环境容量和压力两方面要素,提出水环境约束分区方法,并以无锡市区为例讨论了分区评价单元划分、指标选择与处理等技术方法,通过水环境容量和水环境压力的矩阵分析,将研究区划分为高压高容区、高压低容区、低压高容区和低压低容区等4种类型区,据此提出产业准入与布局调整导向。研究结果可为协调区域产业发展与水环境关系、制定差别化的产业准入政策提供科学依据。     

基于资源约束的装备可持续发展策略研究

随着军队现代化的高速发展,严峻的资源短缺问题日益凸显,严重制约了装备的持续发展。为缓解制约装备可持续发展的资源"瓶颈",必须改变传统的粗放式发展模式,将可持续发展理念贯穿到装备全寿命周期,走资源节约型、环境友好型装备发展道路。结合我军装备建设实际情况,以实现装备可持续发展为前提,从装备科研领域、采购管理、使用管理、维修保障及退役报废5个领域入手,确定当前我军装备发展需要的新目标、新要求,借鉴国内外先进的管理理念和技术,找出适合我军特色的装备可持续发展途径,为下一步装备建设提供参考。     

基于潜变量回归模型的城市火灾风险评估

为评估城市火灾风险等级,针对城市火灾发生的可能性与严重性2个基本问题,建立评估指标体系,提出一种基于潜变量回归的评估模型,并给出无须迭代的确定性算法。该模型和算法无需事先指定风险等级评估分数的训练样本,不必事先指定指标汇总的加权系数,利用合理的配方约束,完成潜变量回归,实现城市火灾风险按地区或者按行业的等级评估,利用现成的软件计算,同样适用于其他具有类似数据结构的评估问题。     

基于系统动力学的安全生产监管有效性研究

为改善我国安全生产监管的效果,研究引入激励性监管措施后的安全生产监管效果。运用系统动力学(SD)建模方法,对比单用约束性监管措施的效果与综合运用约束性监管措施和激励性监管措施的效果。研究结果表明:单独使用约束性监管措施时,提高检查罚金和事故赔偿额,会使企业净收益、政府与企业的净收益总和增加。然而,综合使用约束性监管措施和激励性监管措施时,企业的净收益额增加,政府的净收益额减少,而企业与政府的净收益总额变化不大,但结合对事故负外部性的考虑,通常会使社会福利额外提高。     

志绿隔声产品构建高性能隔声室

为了提高居民居住和工作环境质量,降低噪声对人们的干扰,创造社会一片安宁和谐的氛围,志绿隔声产品将复合高性能新材料形成阻尼约束结构放置在两块板中间,将透过墙板的噪音能量降低85%以上。本文结合项目工程案例,来展现志绿隔声产品的高性能,解决噪声对人们的危害。     

Safety rules: procedural freedom or action constraint?

The paper presents a partial classification of safety rules as constraints imposed from outside on the freedom of choice of individuals or companies. The classification is linked to the Reason model of skill-, rule-, and knowledge-based behaviour. The imposition of constraints is related to a number of criteria concerning the context and use of the rules to arrive at proposals for when and where to apply what type of rule. To illustrate the principles discussed an example is given of the rule from the Dutch Working Environment legislation concerning the requirement to use “current state of the art in prevention” in companies. The paper proposes providing procedural rule support to companies on how to meet the rule, in the form of a data bank of practicable solutions to health and safety problems.     

Pyrrolizidine alkaloid content in <Emphasis Type="Italic">Senecio</Emphasis>: ontogeny and developmental constraints

Summary. The ontogeny of pyrrolizidine alkaloid (PA) synthesis and constraints on defence level during the seedling stage were examined in the annual Senecio vulgaris and the monocarpic perennial Senecio jacobaea. In both species, PAs were actively synthesized from the onset of seedling growth so that juvenile stages did not go through an undefended stage. Roots are known to be the exclusive sites where PAs are produced. Root biomass was the single most important biomass parameter explaining variation in total PAs per seedling. All correlation coefficients between—relative growth rate and PA concentration were negative, but none was significant. However, a significant negative—correlation was found between shoot to root ratio and PA concentration in S. jacobaeaseedlings, suggesting a dilution effect of the PAs. Earlier studies have shown that the shoot to root ratio is positively correlated with relative growth—rate of established S. jacobaea plants. It is therefore suggested that young S. jacobaea plants with a high shoot to root ratio and hence a high growth capacity necessarily have lower PA defence levels than plants with a low shoot to root ratio. Received 10 July 2002; accepted 16 November 2002.     

水资源开发与利用科研工作的现实制约与对策建议

中国人均水资源量少、水资源时空分布不均,近年来经济社会对水资源需求日益增大。在相关领域科技成果的大力支撑下,中国走出了一条有效的水资源管理之路,实现了水资源的高效利用和有效保护。但目前在水资源开发利用的科技活动中仍存在一定的现实制约,本文进行了一定分析,并提出了对策建议。