Visualization and Representation of Physical Systems: Wavemaker as an Aid to Conceptualizing Wave Phenomena

An understanding of wave mechanics is essential to making the leap from classical to quantum systems. Wavemaker is a simulation environment developed to reveal graphically the behavior of periodic systems using a series of increasingly sophisticated visualization tools. Individual particles in a many-particle system can be instrumented for study of kinematic behavior. Parametric representations reveal time-independent behaviors. Problems dealing with propagation, reflection, and Fourier synthesis are easily studied. Use with students has revealed that many students have preconceptions about the behavior of waves and that use of this software is helpful in connecting real to simulated systems, separating holistic behaviors from those of individual elements, identifying critical parameters, and making connections between variables that are used to describe and measure periodic systems.     

皱叶忍冬的组织培养与快速繁殖初步研究

以宜州当地主要金银花品种皱叶忍冬的茎段为外植体材料,于MSt和1/2MS附加不同激素配比的基本培养基上,探讨丛生芽诱导及生根诱导的条件。试验结果表明：丛生芽诱导和继代培养的培养基为MS 6-BA0．5mg／L IBA0．05mg／L,生根培养基为1/2MS IBA1．0mg／L NAA0．05mg／L．     

Accelerate adversarial training with loss guided propagation for robust image classification

Adversarial training is effective to train robust image classification models. To improve the robustness, existing approaches often use many propagations to generate adversarial examples, which have high time consumption. In this work, we propose an efficient adversarial training method with loss guided propagation (ATLGP) to accelerate the adversarial training process. ATLGP takes the loss value of generated adversarial examples as guidance to control the number of propagations for each training instance at different training stages, which decreases the computation while keeping the strength of generated adversarial examples. In this way, our method can achieve comparable robustness with less time than traditional training methods. It also has good generalization ability and can be easily combined with other efficient training methods. We conduct comprehensive experiments on CIFAR10 and MNIST, the standard datasets for several benchmarks. The experimental results show that ATLGP reduces 30% to 60% training time compared with other baseline methods while achieving similar robustness against various adversarial attacks. The combination of ATLGP and ATTA (an efficient adversarial training method) achieves superior acceleration potential when robustness meets high requirements. The statistical propagation in different training stages and ablation studies prove the effectiveness of applying loss guided propagation for each training instance. The acceleration technique can more easily extend adversarial training methods to large-scale datasets and more diverse model architectures such as vision transformers.     

Wave motion of smoke in subway fire environment

Wave motion in subway or tunnel fire is an intrinsic property of smoke.As the pressure of smoke changes with mass of certain power,a kind of linear wave equation for smoke can be derived from the conservation equations of its mass and momentum,under nearly homogeneous zone assumption.The smoke movement of 4 subway fires was simulated with Airpak.By fitting the pressure-mass functions to the simulated data,wave equations of the smoke were derived,and wave motions of smoke were thus validated.It can be seen that smoke wave is a kind of mass wave,whose velocity is inversely proportional to smoke mass,and wave of a bigger fire propagates slower.     

新媒体探析

计算机与信息技术的革命催生了种种新媒体。新媒体是个相对的概念,指的是相对于旧的传统媒体,新近出现的种种传播媒体。目前,从手机到互联网等各种数字媒体是最为常见的新媒体形态。新媒体具有传播主体的多元化、传播内容的多样性、传播行为的主动性、交互性、异步性以及新的传播效力等新的传播特性。     

一种采用自适应机制的分层置信传播算法

提出了一种基于迭代自适应机制的改进算法,有效地缩减了分层置信传播算法(HBP)的计算时间.传统HBP计算时间随指定的迭代上限增加而线性增长.为此引入消息收敛的条件判断,在迭代上限相同情况下,减少算法的迭代次数,缩减整体迭代时间.实验表明,与传统HBP相比,该方法计算时间缩减了38%以上,计算时间对整体迭代上限不敏感.该方法可以应用于使用HBP算法的其他方法.     

突发事件网络谣言传播规律模型研究

分析突发事件网络谣言发生机制,以网民数量变化为研究对象,构建突发事件网络谣言传播规律的宏观模型和微观模型,利用MATALB数值仿真和相轨线分析,研究突发事件网络谣言的传播机理,探讨控制谣言传播的因素,并为政府控制网络谣言传播制定长期策略和近期策略。     

基于复杂网络理论的担保网络风险传播模式

担保作为企业获取贷款的一种方式,扮演着重要的角色,但也隐藏着巨大的风险.本文基于企业间担保关系构建担保网络,利用复杂网络相关理论对担保网络进行基本指标测度,并基于SI模型提出担保网络的风险传播模式,给出衡量担保网络抵御风险能力的稳态风险密度和风险传播速度的定义.利用某金融机构的真实数据对模型进行了验证,发现网络的拓扑结构决定网络抵御风险的能力,不同的风险传染源对风险的传播速度和范围影响不同.这也启示银行在发放贷款前,除做好对企业的征信工作外,还需要考虑可能会对整个担保网络造成的影响.     

基于对冲作用的社交网络中口碑传播模型及控制策略研究

[目的/意义]文章旨在探究社交网络中的口碑传播规律,为现代企业应对口碑传播提供决策参考,对完善网络传播理论具有重要意义。[方法/过程]本文在经典传播模型的基础上,考虑到口碑的时效性及正、负面口碑的对冲作用,构建一种社交网络口碑传播离散模型,分析口碑的传播规律;随后,通过仿真实验分别研究了网络拓扑结构、初始传播节点的度与比例对传播过程的影响;最后,在企业宣传成本的约束条件下,提出了社交网络中负面口碑传播的最优控制策略。[结果/结论]结果表明,在匀质网络中,企业应优先提高传播正面口碑的人群数量;而在异质网络中,选择具有强影响力的媒体或公众人物传播正面口碑是企业的最优选择。     

基于SIRT的网络谣言传播演化模型的研究

本文在传统的SIR模型的基础上加入真实信息传播者,构建了SIRT谣言传播模型,运用Matlab对模型进行仿真。模型考虑了网民对信息的辨识能力、风险认知水平、媒体发布信息透明度、媒体公信力、记忆效应等因素对谣言传播过程的影响,从网民、信息本身和外部作用力3个方面定量的分析谣言传播规律,谣言模型传播演化仿真的结果表明,网民的辨识能力、风险认知水平、媒体发布信息透明度以及媒体公信力等因素都会对谣言传播演化过程产生影响,并提出了谣言应对的建议。