一个加密方案的选择密文安全性的证明

由带Hash的ElGamal加密与Schnorr签名构成的加密方案尽管从直观上看是抗选择密文攻击的,但以前的证明中或者需要在线知识提取假设,或者只能在更受限制的GenericGroup模型中得以证明,因此,其严格的归约化证明仍然是一个公开问题.作者在Gap Diffie-Hellman(GDH)假设下,在Random Oracle模型中,利用了Random Oracle Hash函数的特点模仿解密而严格证明了该方案确实达到了这个强安全级别.     

基于碳排放约束的山东省沿海城镇带能源发展多目标优化决策

针对能源发展中的高能耗问题和碳排放问题,以山东省沿海城镇带为研究区域,将二氧化碳排放因子纳入能源消费结构优化之中,采用多目标规划的方法构建了以碳排放成本最小、能源消费产生的污染物治理费用最小为目标函数,以经济发展规划、能源消费总量、能源消费结构及碳排放量为约束函数的山东省沿海城镇带能源消费结构多目标优化模型。研究区2035年的能源发展多目标优化结果为:煤炭消费量占能源消费总数下降为36%;油类能源消费量占能源消费总数的17%;天然气消费量占能源消费总数的25%;清洁能源占能源消费总数的比例提高到22%,各项指标均满足山东省能源消费的多个目标和约束。同时,针对山东省沿海城镇带低碳情景下的未来发展,提出了加快能源供给侧和能源消费侧的结构性改革、实施清洁能源和电能替代等建议,以加快转变高耗能生产方式,促进经济结构优化升级,实现节能减排、低碳环保的可持续发展。     

基于轮轨定位数据的有轨电车区间驾驶特征分析

为分析人工驾驶条件下有轨电车区间速度及可靠性特征,基于轮轨定位数据,计算有轨电车在加速段、巡航段、制动段和交叉口的运行特征指标,分析人工驾驶决策对各指标的影响机制;并建立区间运行速度的多因素回归分析模型及概率分布模型。结果表明：由于人工驾驶的模糊控制特点,司机无法实现充分加减速;终点速度和制动系数对区间运行速度贡献度总占比达57%,是驾驶行为优化的重点;区间运行速度呈高斯混合分布（Gaussian Mixture Model, GMM）,对常见绿波带宽有较高的偏出率,是造成线路时间可靠性低的重要原因。     

Modelling gene regulation: (De)compositional and template-based strategies

Although the interdisciplinary nature of contemporary biological sciences has been addressed by philosophers, historians, and sociologists of science, the different ways in which engineering concepts and methods have been applied in biology have been somewhat neglected. We examine – using the mechanistic philosophy of science as an analytic springboard – the transfer of network methods from engineering to biology through the cases of two biology laboratories operating at the California Institute of Technology. The two laboratories study gene regulatory networks, but in remarkably different ways. The research strategy of the Davidson lab fits squarely into the traditional mechanist philosophy in its aim to decompose and reconstruct, in detail, gene regulatory networks of a chosen model organism. In contrast, the Elowitz lab constructs minimal models that do not attempt to represent any particular naturally evolved genetic circuits. Instead, it studies the principles of gene regulation through a template-based approach that is applicable to any kinds of networks, whether biological or not. We call for the mechanists to consider whether the latter approach can be accommodated by the mechanistic approach, and what kinds of modifications it would imply for the mechanistic paradigm of explanation, if it were to address modelling more generally.     

Modelling and knowledge transfer in complexity science

I analyse the construction and transfer of models in complexity science. Thereby, I introduce a distinction between (i) vertical model construction, which is based on knowledge about a specific target system, (ii) horizontal model construction, which is based on the alteration of an existing model and therefore does not require any references to a specific target system; and (iii) the transfer of models, which consists of the assignment of an existing model to a new target system. I argue that, in complexity science, all three of those modelling activities take place. Furthermore, I show that these activities can be divided into two general categories: (i) the creation of a repository of models without specific target systems, which have been created by large-scale horizontal construction; and (ii) the transfer of these models to particular target systems in the natural sciences, which can also be followed by an extension of the transferred model through vertical construction of adaptions and additions to its dynamics. I then argue that this interplay of different modelling activities in complexity science provides a mechanism for the transfer of knowledge between different scientific fields. It is also crucial to the interdisciplinary nature of complexity science.     

Explanation,understanding, and unrealistic models

How can false models be explanatory? And how can they help us to understand the way the world works? Sometimes scientists have little hope of building models that approximate the world they observe. Even in such cases, I argue, the models they build can have explanatory import. The basic idea is that scientists provide causal explanations of why the regularity entailed by an abstract and idealized model fails to obtain. They do so by relaxing some of its unrealistic assumptions. This method of ‘explanation by relaxation’ captures the explanatory import of some important models in economics. I contrast this method with the accounts that Daniel Hausman and Nancy Cartwright have provided of explanation in economics. Their accounts are unsatisfactory because they require that the economic model regularities obtain, which is rarely the case. I go on to argue that counterfactual regularities play a central role in achieving ‘understanding by relaxation.’ This has a surprising implication for the relation between explanation and understanding: Achieving scientific understanding does not require the ability to explain observed regularities.     

在实际建筑工程造价管理中运用工程量清单计价模式的一点思考

正确认识工程量清单计价模式,分析在实际建筑工程造价管理中运用该模式可能出现的问提,大力推行工程量清单计价模式,实现市场经济体制下建筑行业的公平竞争。     

多层屏蔽共面波导模型及其实验

提出了一个屏蔽多层共面波导模型.由这个模型可以演变出20种非对称共面波导.为了获得特性阻抗和相对有效介电常数的封闭解析表达式,采用保角交换方法对所提出的模型进行了分析.然后利用该模型分析了一个共面波导的特例,对这个特例进行了计算并制作了这个特例的样品.采用时域反射法对样品的特性阻抗和相对有效介电常数进行了测试.通过比较理论计算与实验结果,说明了这个模型是准确和有效的.     

新股价值低估的随机前沿分析

把新股价值低估作为新股发行的间接成本，综合考虑1999至2001年在沪深两市首次公开发行、外资股增发和A股增发共341只新股．应用随机前沿成本函数，从整体上测度新股间接发行成本的合理性。研究发现，新股价值低估程度远高于随机前沿成本函数决定的成本前沿，说明新股发行过程中有较多的不合理间接发行成本，效率损失比较严重。     

基于Choquet积分的HMM商品信息抽取方法

电子商务网站使用不同的网页编码技术和页面布局为比较购物信息获取带来了很大的难度.基于隐马尔可夫模型(HMM)的信息抽取模型有着易于建立、适应性强等优点,被视为一种有效的信息抽取方法.但是这种算法存在状态序列计算复杂、难以训练优化抽取模型等缺点.本文应用模糊积分单调性建立基于Choquet积分的隐马尔可夫模型(CI-HMM),解决HMM观察序列概率计算所需的条件独立性假设,优化HMM观察序列的计算.本文以网上书店商品数据进行实证,实验证明CI-HMM比HMM有更好适用性和精确度.