基于人工免疫系统的僵尸短信入侵检测

针对移动僵尸网络日益活跃的现状,提出一种基于人工免疫的僵尸短信入侵检测模型。该模型包含两个核心模块,短信过滤模块提取短信号码与黑名单信息相匹配初步过滤垃圾短信和广告;短信识别免疫模块量化短信的签名信息生成抗原,采用实值否定选择算法生成抗体,通过抗原与抗体的亲密程度识别僵尸短信,最后根据用户反馈结果更新抗体。实验结果表明:该模型具有较高的检测率,证明了其可行性。     

Incorporating Intra‐Query Term Dependencies in an Aspect Query Language Model

Query language modeling based on relevance feedback has been widely applied to improve the effectiveness of information retrieval. However, intra‐query term dependencies (i.e., the dependencies between different query terms and term combinations) have not yet been sufficiently addressed in the existing approaches. This article aims to investigate this issue within a comprehensive framework, namely the Aspect Query Language Model (AM). We propose to extend the AM with a hidden Markov model (HMM) structure to incorporate the intra‐query term dependencies and learn the structure of a novel aspect HMM (AHMM) for query language modeling. In the proposed AHMM, the combinations of query terms are viewed as latent variables representing query aspects. They further form an ergodic HMM, where the dependencies between latent variables (nodes) are modeled as the transitional probabilities. The segmented chunks from the feedback documents are considered as observables of the HMM. Then the AHMM structure is optimized by the HMM, which can estimate the prior of the latent variables and the probability distribution of the observed chunks. Our extensive experiments on three large‐scale text retrieval conference (TREC) collections have shown that our method not only significantly outperforms a number of strong baselines in terms of both effectiveness and robustness but also achieves better results than the AM and another state‐of‐the‐art approach, namely the latent concept expansion model. © 2014 Wiley Periodicals, Inc.     

How do Individual‐Level Factors Affect the Creative Solution Formation Process of Teams?

The generation of creative solutions involves nonlinear dynamic procedures that can only be achieved through the creativity of individual team members. Thus, it is important to understand how the formation of individual‐level creativity factors influence the creative solution formation process. The creative solution formation process can be divided into four phases: idea generation, idea screening, idea development and solution verification. Prior research suggests that the creative process may be affected by motivation (intrinsic and extrinsic), knowledge stock (explicit and tacit), individual creativity (intelligence and divergent thinking), and pressure (challenge and time). We tested the effects of these eight factors on performance in the idea generation and idea development phases by conducting an experiment. Our results indicate that intrinsic motivation, intelligence and divergent thinking have a significant positive effect on both idea generation and idea development. Tacit knowledge and challenge pressure have a significant positive effect on idea generation. Time pressure has a significant negative effect on idea development. We also show that both idea generation and idea development have a significant impact on the quality of the final creative solution.     

Comparison of spherical and non-spherical particles in microchannels under dielectrophoretic force

This paper focuses on the computational and experimental study of dielectrophoretic (DEP) force based manipulation of spherical and non-spherical particles by taking into consideration of both electrokinetic effects and particle hydrodynamics. The model is first validated with conventional dipole moment theory. The movements of a spherical polystyrene particle and a rod-shape particle under a non-uniform electric field created by a pair of non-symmetrical electrodes in a microfluidic channel are studied, and a good agreement between the simulation and experimental results is obtained. Both experimental and simulation results reveal that the rod-shape particle experiences larger DEP force and moves faster than spherical particle with a similar mass. It was also interestingly found that the shape-dependent DEP force distribution on the microscale rod particle results in its unique behavior, which cannot be captured by traditional DEP theory.     

航班着陆调度的多目标优化研究

航班着陆调度问题是多目标优化问题,难以使用最优化方法求解。为了解决这一难题,以减少航班延迟时间和降低飞行延误成本为目标,提出一种整合的启发式方法。该方法使用吱呀轮算法SWO(Squeaky-Wheel Optimization)进行导向式搜索,并利用改进的GA充分扩展SWO的搜索空间,最后通过合理整合GA和SWO,取得求解效率和求解质量的提高。通过实验仿真对比表明该算法能高效求解该问题,满足了实时调度的需求,同时求解质量也优于其他启发式算法,节省了更多降落时间和成本。     

标准模型下基于身份的签密密钥封装

针对随机预言模型下的签密密钥封装机制依赖现实世界无法实现的随机预言假设的问题,提出在标准模型下可证明安全的基于身份签密密钥封装机制(IBSC-KEM)。新提出的IBSC-KEM方案基于一种受到广泛研究的身份加密机制,在标准模型下被规约为求解q-ABDHE问题和判定性q-ABDHE问题,具有机密性和不可伪造性。新方案主要计算开销为5次群G上的指数运算、3次群GT上的指数运算和3次双线性对运算,与类似的签密方案比较,计算开销较低。此外,新方案还具有公开可验证性,适用于构建安全的端到端传输。     

基于速龙码的WSNs传输功率控制重编程协议

为了降低节点能耗,提高能量的利用率,提出了一种高效节能的基于速龙码（ RC）的传输功率控制（ RC-TPC）重编程协议。该协议分两个阶段完成数据传输,第一阶段各个节点更新自己的位置信息,形成最优化的拓扑结构。进入第二阶段后,根据优化的拓扑结构通过调整发送节点的传输功率和中继节点的累计选择次数,Sink节点选择适当的中继节点,使中继节点的传输功率和RC的开销达到最优化。此外,RC的编码方式使传输数据包发生的错误概率更小,减少了重编程过程中的冗余以保证网络负载的均匀分布,有效地实现了高效节能,从而提高整个网络的生存周期。理论分析与实验结果表明：与MNP协议和ATPC协议相比,RC-TPC协议用于传输的平均能量消耗降低17.2%。     

基于云模型的无线传感器网络链路质量的预测

无线传感器网络中,节点通过单跳或多跳传递信息.如能提前获知链路质量信息,为上层路由选择链路提供参考,是感知信息实时、准确地送达监控中心的基础.在分析现有基于智能学习链路质量预测方法的基础上,提出一种基于云模型的链路质量预测机制.通过收集不同场景下的链路质量样本,采用自适应高斯云变换对训练样本中的 RSSI(received signal strength indication),LQI(link quality indicator),SNR(received signal strength indication)及PRR(packet reception rate)进行链路划分;考虑到传感器节点的资源受限问题,采用 Apriori 算法对划分后的链路质量参数 RSSI,LQI,SNR 及 PRR 进行关联规则挖掘;在此基础上,基于三维云正向发生器预测链路质量.仿真结果表明,与基于 BP 神经网络的预测方法相比,提出的链路质量预测机制具有较高的预测精度.     

灰色Verhulst 模型背景值优化及其应用

鉴于背景值是影响灰色建模精度的重要因素之一, 提出一种灰色Verhulst 模型中背景值的优化方法. 基于灰色Verhulst 模型时间响应式的Logistic 函数形式和背景值的几何意义, 利用积分中值定理研究背景值与发展系数之间的数量关系; 采用最小二乘法对新参数进行估计, 还原原始参数估计值, 使得优化的背景值模型同时具备无偏性和最小误差性. 案例分析表明, 背景值优化的模型改善了模拟精度, 验证了模型的有效性和可行性.

     

NO在(Fe_2O_3)_n(2≤n≤6)团簇上吸附的密度泛函理论研究

运用广义梯度密度泛函理论(GGA)的Pcrdew-Burke-Emrnerh(PBE)方法结合团簇模型,在双数值极化函数基组DNP下,研究了(Fe_2O_3)_n(2≤n≤6)团簇的性质和NO在其上的吸附。对于(Fe_2O_3)_n团簇通过对几何构型和性质的计算发现;(Fe_2O_3)_n团簇都具有很高的稳定性并且它们的结构和成键性质都和体材料Fe_2O_3有很大的不同;NO主要以N端吸附在Fe_2O_3团簇Fe-top位。NO在(Fe_2O_3)_n团簇上吸附为化学吸附,对应于n从2~6,吸附能分别为1.792、1.976、2.799、2.963和2.536 eV。Mulliken布局分析结合NO吸附前后的态密度分析表明:吸附前后电子由NO向(Fe_2O_3)_n团簇转移,吸附时NO的5口轨道趋向于转移电子给Fd~(3+)的d轨道,使Fe位形成d~(10)稳定电子构型,同时Fe反馈电子给NO的知反键轨道,总体上为NO失去电子。