改进PSRK模型预测高分子溶液的活度系数

为了更好地预测高分子溶液的活度系数，结合简化的EOS／G^E混合规则，建立了改进基团贡献状态方程PSRK（Predictive Soave—Redlich—Kwong）模型，外推法得到无限稀释活度系数。考虑了自由体积效应对溶液的过量Gibbs自由能的贡献。该模型形式较为简单，其预测结果与实验值具有较好的一致性，优于其他基团贡献型模型。     

若干电解质浓溶液活度系数估算的支持向量回归算法

应用支持向量回归算法筛选出与电解质浓溶液活度系数相关的离子特性参数集：阴阳离子半径比(R．／Rm)、阴离子半径Rm、阳离子半径R．和阴阳离子电荷数比(Zx／Zm)。并以此为自变量集，用支持向量回归算法或PLS算法总结活度系数的经验规律，进而提出利用一批浓电解质溶液已知的活度系数数据“转推”其他电解质溶液的活度系数的算法。用留一法考察了这种“转推”算法的准确程度。并引用离子系的对应态理论对支持向量回归求得的经验关系的物理意义作了讨论和解释。     

UNIFAC-ZM活度系数模型预测聚合物溶液中溶剂扩散系数

根据Vrentas-Duds自由体积理论，结合基于UNIFAC活度系数模型，在较宽的浓度范围内预测了聚合物溶液中小分子的扩散行为。对某些聚合物体系，计算结果和实验数据基本一致。表明UNIFAC-ZM模型可代替Flory-Huggins方程用于预测聚合物溶液中小分子扩散系数。调节自由体积模型中的指前因子D0数值可改善预测结果。     

Entropic-FV活度系数模型预测膜的溶胀性能

根据Vrentas-Duda自由体积理论，结合基于UNIFAC活度系数模型，在较宽的浓度范围内预测了聚合物膜在溶液中溶胀行为。用UNIQUAC方程计算液相中组分的活度，考虑了温度对模型方程中二元交互作用参数的影响。对水／乙二醇(EG)／聚乙烯醇(PVA)膜体系，三个不同温度60℃、70℃和80℃下计算结果和实验数据基本一致。模型方程中自由体积部分影响较大，考虑聚合物的粘弹性贡献对预测结果有一定改进。     

电解质溶液相平衡预测系统的建立

建立了电解质溶液相平衡预测系统ＰＨＥＥＳ。该系统可预测电解质溶液的活度系数、参透系数、相对摩尔焓、蒸汽压及固液平衡、溶度积等，预测准确度符合工程要求，所有计算结果均能自动输出表格和相应图形。     

应用UNIFAC法计算非电解质溶液的活度系数

UNIFAC基团贡献法是目前流行的一种重要的推算汽液平衡的方法,可用以预测化工生产中遇到的许多非电解质液体混合物的活度系数。本文对一百三十三个体系应用UNIFAC 模型在微机上进行了计算,并对该模型的活度系数计算结果与文献实验值作了比较,从而对模型的实际应用作出了估计。     

电解质NRTL模型研究与开发

基于同种离子间相互排斥以及局部电中性这两种基本假设,根据Chen等1988年模型建立的可适用于混合溶剂电解质溶液体系热力学性质的计算模型,纯水性质采用IAPWS-97物性方法进行计算,对该电解质NRTL活度系数模型求解并开发,并采用工业中含电解质流程的相关实例进行验证,以及与Aspen plus软件在相同物性数据下的计算结果相比,开发的模型在计算单一电解质水溶液体系的活度系数、吉布斯自由能和焓值等数据方面的相对偏差低至0.0%,混合溶剂电解质溶液体系的计算结果偏差也都在0.1%以下,采用文献中的交互参数由于参数取值的差别导致相对偏差偏大,但也都在0.5%以下,从而表明该开发的模型可以应用于含电解质流程的模拟、计算和优化。     

钾离子选择电极在土壤研究中的应用

由于离子选择电极的发展，它在土壤学研究得到了广泛的应用，本文根据所在实验室近年来研究工作的进展，简要介绍了钾电极在土壤中速效钾的快速测定，钾电极作为参比电极，土壤中钾－钙活度比测定，土壤中钾－钠活度比的测定和铵离了在土壤中的扩散的研究等方面的应用。     

UNIFAC法计算糠醛—抽出油系统活度系数的灵敏度分析

本文针对 UNIFAC 基团贡献法中交互作用参数变化对活度系数的影响,建立了灵敏度分析模型,根据此模型在 IBM-PC/XT 机上分别试算了大连石油七厂减二线、减三线抽出油与糠醛体系的活度系数灵敏度,从而对此模型的实际应用作出了估计。     

基于晶格理论的聚合物溶液活度模型

根据Gibbs-Helmholtz热力学基本关系式,结合溶液晶格模型推导出适合聚合物体系的活度系数模型,该模型方程含有结合项、剩余项和自由体积项。将其与Entropic-FV(EFV)、UNIFAC-FV及UNIFAC模型,同时用于预测14个由PIB、PS和PPO等聚合物与苯、甲苯和丁烷等溶剂组成的聚合物-溶剂体系中溶剂的活度,并与实验数据进行比较,活度的平均偏差分别为3．98%、6．61%、4．92%、19．19%。计算结果显示该模型的预测精度高于其它3种常用的聚合物、溶剂体系的溶剂活度模型。     

Dependability modeling of Software Defined Networking

Software Defined Networking (SDN) is a new network design paradigm that aims at simplifying the implementation of complex networking infrastructures by separating the forwarding functionalities (data plane) from the network logical control (control plane). Network devices are used only for forwarding, while decisions about where data is sent are taken by a logically centralized yet physically distributed component, i.e., the SDN controller. From a quality of service (QoS) point of view, an SDN controller is a complex system whose operation can be highly dependent on a variety of parameters, e.g., its degree of distribution, the corresponding topology, the number of network devices to control, and so on. Dependability aspects are particularly critical in this context. In this work, we present a new analytical modeling technique that allows us to represent an SDN controller whose components are organized in a hierarchical topology, focusing on reliability and availability aspects and overcoming issues and limitations of Markovian models. In particular, our approach allows to capture changes in the operating conditions (e.g., in the number of managed devices) still allowing to represent the underlying phenomena through generally distributed events. The dependability of a use case on a two-layer hierarchical SDN control plane is investigated through the proposed technique providing numerical results to demonstrate the feasibility of the approach.     

Numerical solution of nonstationary problems for a system of nernst-planck equations

The mathematical model of electricity and mass transfer is based on the equations for charged particles (ions and cations) in the electrolyte, i.e., the Nernst-Planck equations. These equations are supplemented by the equation for the electric field and the motion equations for the electrolyte as a continuum. The paper mostly focuses on the construction of the time approximation for the approximate solution of nonstationary problems. The system of Nernst-Planck equations is characterized by a quadratic nonlinearity. Special linearization schemes are proposed for taking this into account. Computational algorithms are studied on a model problem for the binary electrolyte (two kinds of charged particles).     

Nash Play Strings of Symmetric Games and Their Language Classes

Abstract

It is an interesting point of view to consider N-person games as models of human behavior and their decision making processes in the society. Bryzgalov et al. [1] have proposed a kind of N-person game in which all players are equivalent, i.e., homogeneous games. In this paper, considering one of the homogeneous games, i.e., symmetric games, and assuming the patterns of Nash play strings as a language, we determine the language classes of them.     

Context-Aware, Proactive Delivery of Task-Specific Information: The KnowMore Project

From an IT point of view, a key objective of successful knowledge management is to provide relevant and necessary information at the right time to support humans in accomplishing their tasks. This paper presents a prototypical system which meets this objective in an enterprise environment. Based on context information associated with the enterprise's business processes, an integration of workflow engine and information assistant enables active presentation of relevant information to the user. We describe the functionality of the system and elaborate (i) on necessary extensions to the business process models, (ii) the ontologies used for information modeling, and (iii) the integration of workflow engine and active information assistant. The prototype system has been developed in the KnowMore project of the DFKI Knowledge Management Group.     

ON THE NATURE OF CULTURE AND COMMUNICATION: A COMPLEX SYSTEMS PERSPECTIVE

ABSTRACT

This article describes the foundations of a new theory of communication as the generative core of cultural systems. We define the concepts of meaning and information in terms of complex systems theory; communication is considered as the interplay of social and cognitive dynamics, i.e., interactions between speakers and receivers, which are determined by social and cognitive rules. The theory is validated by several computational models developed to analyze some important aspects of the theoretical foundations. The computational models themselves are validated by some empirical social experiments with student groups.     

A different paradigm for expert systems: an introduction to logic programming and related knowledge representation issues

Abstract: Current expert system technology is 30 years old. Expert system shells find their origins in the work of early expert systems, most notably MYCIN which was developed at Stanford in the mid-1970s. Even Prolog programmers are settling for less robust reasoning power. The logic programming community (from which both expert systems and Prolog arose) has made notable advances since those times. These advances are lacking from current expert system technology. The advances include a well-developed theory of multiple forms of negation, an understanding of open domains and the closed world assumption, default reasoning with exceptions, reasoning with respect to time (i.e. a solution to the frame problem, and introspection with regard to previous beliefs), reasoning about actions, introspection, and maintaining multiple views of the world simultaneously.
The contribution of this paper is to discuss these developments in a singular, integrated, practical, digestible manner. Some of these ideas exist in a variety of papers spread across decades. They also exist in the minds of a very small community of researchers. Some of these ideas are unpublished. The presentation in this paper is from a different point of view, and intended to be more comprehensive and pedagogical. The presentation is also intended to be accessible to a much wider audience. Both the synthesis and the simplicity of this presentation are absent from the literature.     

New local composition model for modeling of thermodynamic and transport properties of binary aqueous electrolyte solutions

A new local composition model, which is an NRF-modified-NRTL (NRF-mNRTL) model, is developed for the representation of the excess Gibbs energy of electrolyte solutions. In this model for excess Gibbs energy the sum of a long-range and a short-range term is used. The contribution of the long-range excess Gibbs energy is represented by the Pitzer-Debye-Hückel model. A new expression based on the local composition concept has been developed to account for the contribution of the short range excess Gibbs energy. The model is applied to correlate the mean ionic activity coefficients and osmotic coefficients of more than respectively 150 and 290 binary aqueous electrolyte solutions at 25 °C. The fitting quality of the new model has been favorably compared with the electrolyte NRTL, Wilson, modified NRTL, NRTL-NRF, NRF-Wilson, UNIQUAC-NRF, Pitzer and TCPC models. Viscosity values of the binary aqueous solution of electrolytes have also successfully been correlated with the proposed local composition model by considering the Eyring absolute rate theory. The validity of the proposed model is specially demonstrated for multivalent electrolyte binary solutions encompassing the entire range of composition.     

A multilevel multilayer framework for manufacturing control

As a contribution to the debate on CAPM reference models derived from control theory concepts, we formulate the basic computer-aided production management problem from a control theoretic point of view and examine the main difficulties in using this crude framework as a basis for decision-making. Next, different hierarchical approaches are shown to be potentially of value in overcoming the two main difficulties highlighted by the control theoretic paradigm, i.e. dimensionality and the discrete event nature of manufacturing systems. In this context, we examine the literature concerned with both multilevel control as well as multilayer control where the notion of aggregation plays a key role. Next, a mixture of multilevel and multilayer control is used to provide a framework for production planning and scheduling for multiline batch manufacture with application to detergents plants. This framework would appear to be of values also in discrete parts manufacture and this is also highlighted.     

Global exponential stability of competitive neural networks with different time scales

The dynamics of cortical cognitive maps developed by self-organization must include the aspects of long and short-term memory. The behavior of such a neural network is characterized by an equation of neural activity as a fast phenomenon and an equation of synaptic modification as a slow part of the neural system. We present a new method of analyzing the dynamics of a biological relevant system with different time scales based on the theory of flow invariance. We are able to show the conditions under which the solutions of such a system are bounded being less restrictive than with the K-monotone theory, singular perturbation theory, or those based on supervised synaptic learning. We prove the existence and the uniqueness of the equilibrium. A strict Lyapunov function for the flow of a competitive neural system with different time scales is given and based on it we are able to prove the global exponential stability of the equilibrium point.