基于移动Agent的分布式网管系统设计与实现

提出了一种运用移动Agent技术实现分布式网管的方案,它结合了Java和coRBA等分布式计算技术,并采用基于规则的方法来实现对网络的智能化管理．文中首先研究了基于移动Agent的分布式网管结构,然后深入地讨论了它的系统实现,包括移动Agent的运行环境、结构设计、通信机制以及基于Web的图形用户界面.     

PP Cramèr-von Mises统计量P值的近似计算

本文给出了PPCramer－vonMises统计量极限分布的一种近似计算方法，用一个г分布作为极限分布的近似．当总体分别服从圆周上均匀分布及二元正态分布时，通过模拟计算相应的P值，发现该近似计算办法合理可行．     

Effects of average degree of network on an order-disorder transition in opinion dynamics

We have investigated the influence of the average degree \langle k \rangle of network on the location of an order--disorder transition in opinion dynamics. For this purpose, a variant of majority rule (VMR) model is applied to Watts--Strogatz (WS) small-world networks and Barab\'{a}si--Albert (BA) scale-free networks which may describe some non-trivial properties of social systems. Using Monte Carlo simulations, we find that the order--disorder transition point of the VMR model is greatly affected by the average degree \langle k \rangle of the networks; a larger value of \langle k \rangle results in a more ordered state of the system. Comparing WS networks with BA networks, we find WS networks have better orderliness than BA networks when the average degree \langle k \rangle is small. With the increase of \langle k \rangle, BA networks have a more ordered state. By implementing finite-size scaling analysis, we also obtain critical exponents \beta/\nu, \gamma/\nu and 1/\nu for several values of average degree \langle k \rangle. Our results may be helpful to understand structural effects on order--disorder phase transition in the context of the majority rule model.     

A Modified Potential Method for Electrons Scattering Total Cross Section Calculations on Several Molecules at 30 ～ 5000 eV: CF4, CCl4, CFCl3, CF2Cl2, and CF3Cl

A complex optical model potential modified by the concept of bonded atom, which takes into consideration the overlapping effect of electron clouds between two atoms in a molecule, is employed to calculate the total cross sections (TCSs) for electrons scattering from several molecules (CF4, CCl4, CFCl3, CF2 Cl2, and CF3 Cl) over an incident energy range 30 ～ 5000 eV using the additivity rule model at Hartree-Fock level. The quantitative TCSs are compared with those obtained by experiments and other theories wherever available, and good agreement is obtained above 100 eV.It is shown that the modified potential can successfully calculate the TCSs of electron-molecule scattering over a wide energy range, especially at lower energies.     

考虑乘客取消订单的网约车平台定价策略

针对乘运市场供需不匹配的情况,考虑乘客在网约车平台预约订单后的取消行为,以平台利润最大化为目标,首先建立乘客选择模型计算乘客取消订单概率,再分别构建市场供过于求和供不应求状态下的利润模型,求解平台最优定价。研究表明:制定适当的违约规则可以有效减少乘客取消订单的概率,提高平台利润;最优定价随着服务质量的提高而增加,在打车非高峰期,平台可以通过提高服务质量来增加平台利润;非高峰期平台最优定价随着出租车费用的增加而减少,而高峰期定价策略受出租车费用影响较小。     

Quantum Theory of the Classical: Einselection,Envariance, Quantum Darwinism and Extantons

Core quantum postulates including the superposition principle and the unitarity of evolutions are natural and strikingly simple. I show that—when supplemented with a limited version of predictability (captured in the textbook accounts by the repeatability postulate)—these core postulates can account for all the symptoms of classicality. In particular, both objective classical reality and elusive information about reality arise, via quantum Darwinism, from the quantum substrate. This approach shares with the Relative State Interpretation of Everett the view that collapse of the wavepacket reflects perception of the state of the rest of the Universe relative to the state of observer’s records. However, our “let quantum be quantum” approach poses questions absent in Bohr’s Copenhagen Interpretation that relied on the preexisting classical domain. Thus, one is now forced to seek preferred, predictable, hence effectively classical but ultimately quantum states that allow observers keep reliable records. Without such (i) preferred basis relative states are simply “too relative”, and the ensuing basis ambiguity makes it difficult to identify events (e.g., measurement outcomes). Moreover, universal validity of quantum theory raises the issue of (ii) the origin of Born’s rule, pk=|ψk|2, relating probabilities and amplitudes (that is simply postulated in textbooks). Last not least, even preferred pointer states (defined by einselection—environment—induced superselection)—are still quantum. Therefore, unlike classical states that exist objectively, quantum states of an individual system cannot be found out by an initially ignorant observer through direct measurement without being disrupted. So, to complete the ‘quantum theory of the classical’ one must identify (iii) quantum origin of objective existence and explain how the information about objectively existing states can appear to be essentially inconsequential for them (as it does for states in Newtonian physics) and yet matter in other settings (e.g., thermodynamics). I show how the mathematical structure of quantum theory supplemented by the only uncontroversial measurement postulate (that demands immediate repeatability—hence, predictability) leads to preferred states. These (i) pointer states correspond to measurement outcomes. Their stability is a prerequisite for objective existence of effectively classical states and for events such as quantum jumps. Events at hand, one can now enquire about their probability—the probability of a pointer state (or of a measurement record). I show that the symmetry of entangled states—(ii) entanglement—assisted invariance or envariance—implies Born’s rule. Envariance also accounts for the loss of phase coherence between pointer states. Thus, decoherence can be traced to symmetries of entanglement and understood without its usual tool—reduced density matrices. A simple and manifestly noncircular derivation of pk=|ψk|2 follows. Monitoring of the system by its environment in course of decoherence typically leaves behind multiple copies of its pointer states in the environment. Only pointer states can survive decoherence and can spawn such plentiful information-theoretic progeny. This (iii) quantum Darwinism allows observers to use environment as a witness—to find out pointer states indirectly, leaving systems of interest untouched. Quantum Darwinism shows how epistemic and ontic (coexisting in epiontic quantum state) separate into robust objective existence of pointer states and detached information about them, giving rise to extantons—composite objects with system of interest in the core and multiple records of its pointer states in the halo comprising of environment subsystems (e.g., photons) which disseminates that information throughout the Universe.     

History and Future of Dative Bonds

Dative Bond (IUPAC): “The coordination bond formed upon interaction between molecular species, one of which serves as a donor and the other as an acceptor of the electron pair to be shared in the complex formed… The distinctive feature of dative bonds is that their minimum-energy rupture in the gas phase or in inert solvent follows the heterolytic bond cleavage path.” This definition encompasses an immense number of molecules such as Lewis adducts, transition-metal complexes, supposedly hypervalent or hypovalent systems, and many molecules with multifaceted Lewis structures. Still, there is a large reticence to include dative bonds in the regular depiction of molecules, and even a larger unawareness of the dative bond arrow in many chemical circles. Herein we will discuss in simple chemical terms the past, present and future of such bonds. In addition, we will try to provide cleaner options to represent intricate molecules without sacrificing physical accuracy.     

高二学生掌握化学平衡命题的潜在类别分析和Apriori算法研究*

高中生对化学平衡的理解是重要且仍待深入探索的研究问题。潜在变量模型和数据挖掘有助于研究者从新角度了解学生的化学平衡概念学习情况。本研究使用自编的化学平衡命题测验,应用潜在类别分析和Apriori算法呈现722名高二年级学生对化学平衡命题的掌握情况。研究发现:(1)学生适合被分为3个组别,分别为高掌握水平组、中掌握水平组和低掌握水平组;(2)根据本研究设定的参数条件,未在高掌握水平组学生的作答中获得关联规则,在中掌握水平组和低掌握水平组学生的作答中获得了一些关联规则。潜在类别分析和Apriori算法可被用于化学概念学习和其他主题的研究。