Application of collective knowledge diffusion in a social network environment

ABSTRACT

We present a group dynamics model that shows knowledge integration as a process occurring over time. As each individual in the group contact others, his own knowledge changes, and over time the collective knowledge is obtained. This allows modeling knowledge diffusion in a social network and while the models presented in this paper are not competitive in that area, they approach the problem from previously unconsidered direction. We test the behavior of the model in a multi-agent simulation and we test a simple advertisement campaign in a social network. We provide discussion of elements needed for making model more competitive.     

Simulating the Evolution of the Implied Distribution

Motivated by the implied stochastic volatility literature (Britten–Jones and Neuberger, forthcoming; Derman and Kani, 1997; Ledoit and Santa–Clara, 1998) this paper proposes a new and general method for constructing smile–consistent stochastic volatility models. The method is developed by recognising that option pricing and hedging can be accomplished via the simulation of the implied risk neutral distribution. We devise an algorithm for the simulation of the implied distribution, when the first two moments change over time. The algorithm can be implemented easily, and it is based on an economic interpretation of the concept of mixture of distributions. It can also be generalised to cases where more complicated forms for the mixture are assumed.     

Government Deficit, Public Investment, and Public Capital in the Transition to an Aging Japan

This paper examines the effects of government deficits, public investment, and public capital on welfare in the transition to an aging Japan by applying a simulated general equilibrium growth model. One of the main results of this paper is that targeting only high economic growth would mislead us as to economic policies, and that a policy to reduce future government deficits is most preferable for almost all generations, even though a cut in future deficits must be followed by a decrease in public investment, thus a decrease in public capital in the future. J. Japan. Int. Econ., December 2002, 16(4), pp. 462–491. Faculty of Economics, Shiga University, Japan; and Management School, Imperial College, United Kingdom. © 2002 Elsevier Science (USA).Journal of Economic Literature Classification Numbers: H55, H54, H62, C68, J10.     

Dominance Statistics: A Simulation Study on the d Statistic

Quality &; Quantity - Cliff (1993) has proposed the use of a measure of effect size alternative to traditionalmean differences: δ {? = Pr(xi1 &;gt; xj2) - Pr(xi1 &;lt; xj2)}which,...     

面向供应链管理的库存问题与对策

以两个典型企业为例,比较研究了我国制造型企业在面向供应链管理的库存控制中的现象和企业行为特征,将所存在的问题归结为面向企业外部和内部两个层次。针对面向企业内部的问题探讨了解决对策,并讨论了用仿真作为供应链库存控制问题对策研究的基本方法的可行性和应用前景。     

Simulation driven inferences for multiply imputed longitudinal datasets*

In this article, we demonstrate by simulations that rich imputation models for incomplete longitudinal datasets produce more calibrated estimates in terms of reduced bias and higher coverage rates without duly deflating the efficiency. We argue that the use of supplementary variables that are thought to be potential causes or correlates of missingness or outcomes in the imputation process may lead to better inferential results in comparison to simpler imputation models. The liberal use of these variables is recommended as opposed to the conservative strategy.     

基于计算机仿真的堆石坝坝面流水施工方案研究

根据流水施工的基本原理和堆石坝填筑的施工特点，利用计算机仿真技术对堆石坝施工交通运输系统进行模拟，考虑了堆石坝土石方挖运对其坝面流水施工的影响，合理确定出坝面流水施工方案，使其既能够满足施工进度所要求的填筑强度，又能够保证各分区可以进行流水施工。     

Agglomeration in an innovative and differentiated industry with heterogeneous knowledge spillovers

This paper introduces an agent-based simulation model to study the technological development, the economic performance of firms and the evolution of agglomerations in a differentiated industry. The analysis is based on the interaction and behavior of firms, which might share knowledge but at the same time are competitors on the goods markets. Firms do not only compete with quantities they can also introduce process and product innovations. The level of knowledge of a firm describes the capabilities to perform innovations. Knowledge can be accumulated by investing in R&D and by knowledge spillover, which depend on geographical and technological proximity. Simulation runs show that there is an incentive to agglomerate in young industries and that geographical proximity enhances innovation, especially the number of product innovations.      

村镇连锁经营配送系统关键技术问题分析

论文充分考虑村镇连锁经营配送系统的影响因素．对村镇连锁经营配送系统中的配送中心规划仿真技术和城乡双向物流问题进行深入的技术分析．同时提出了典型的村镇连锁经营管理与配送决策模型。     

Testing equality of variances in the analysis of repeated measurements

The problem of comparing the precisions of two instruments using repeated measurements can be cast as an extension of the Pitman-Morgan problem of testing equality of variances of a bivariate normal distribution. Hawkins (1981) decomposes the hypothesis of equal variances in this model into two subhypotheses for which simple tests exist. For the overall hypothesis he proposes to combine the tests of the subhypotheses using Fisher's method and empirically compares the component tests and their combination with the likelihood ratio test. In this paper an attempt is made to resolve some discrepancies and puzzling conclusions in Hawkins's study and to propose simple modifications.
The new tests are compared to the tests discussed by Hawkins and to each other both in terms of the finite sample power (estimated by Monte Carlo simulation) and theoretically in terms of asymptotic relative efficiencies.